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Rau A, Reisert M, Stein T, Mueller-Peltzer K, Rau S, Bamberg F, Taschner CA, Urbach H, Kellner E. Impact of temporal resolution on perfusion metrics, therapy decision, and radiation dose reduction in brain CT perfusion in patients with suspected stroke. Neuroradiology 2024; 66:749-759. [PMID: 38498208 PMCID: PMC11031466 DOI: 10.1007/s00234-024-03335-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 03/11/2024] [Indexed: 03/20/2024]
Abstract
PURPOSE CT perfusion of the brain is a powerful tool in stroke imaging, though the radiation dose is rather high. Several strategies for dose reduction have been proposed, including increasing the intervals between the dynamic scans. We determined the impact of temporal resolution on perfusion metrics, therapy decision, and radiation dose reduction in brain CT perfusion from a large dataset of patients with suspected stroke. METHODS We retrospectively included 3555 perfusion scans from our clinical routine dataset. All cases were processed using the perfusion software VEOcore with a standard sampling of 1.5 s, as well as simulated reduced temporal resolution of 3.0, 4.5, and 6.0 s by leaving out respective time points. The resulting perfusion maps and calculated volumes of infarct core and mismatch were compared quantitatively. Finally, hypothetical decisions for mechanical thrombectomy following the DEFUSE-3 criteria were compared. RESULTS The agreement between calculated volumes for core (ICC = 0.99, 0.99, and 0.98) and hypoperfusion (ICC = 0.99, 0.99, and 0.97) was excellent for all temporal sampling schemes. Of the 1226 cases with vascular occlusion, 14 (1%) for 3.0 s sampling, 23 (2%) for 4.5 s sampling, and 63 (5%) for 6.0 s sampling would have been treated differently if the DEFUSE-3 criteria had been applied. Reduction of temporal resolution to 3.0 s, 4.5 s, and 6.0 s reduced the radiation dose by a factor of 2, 3, or 4. CONCLUSION Reducing the temporal sampling of brain perfusion CT has only a minor impact on image quality and treatment decision, but significantly reduces the radiation dose to that of standard non-contrast CT.
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Affiliation(s)
- Alexander Rau
- Department of Neurology and Clinical Neuroscience, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
- Department of Diagnostic and Interventional Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Marco Reisert
- Department of Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Stereotactic and Functional Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Thomas Stein
- Department of Diagnostic and Interventional Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Katharina Mueller-Peltzer
- Department of Diagnostic and Interventional Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Stephan Rau
- Department of Diagnostic and Interventional Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Fabian Bamberg
- Department of Diagnostic and Interventional Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christian A Taschner
- Department of Neurology and Clinical Neuroscience, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Horst Urbach
- Department of Neurology and Clinical Neuroscience, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Elias Kellner
- Department of Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Lei L, Zhou Y, Guo X, Wang L, Zhao X, Wang H, Ma J, Yue S. The value of a deep learning image reconstruction algorithm in whole-brain computed tomography perfusion in patients with acute ischemic stroke. Quant Imaging Med Surg 2023; 13:8173-8189. [PMID: 38106310 PMCID: PMC10722072 DOI: 10.21037/qims-23-547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 09/19/2023] [Indexed: 12/19/2023]
Abstract
Background Computed tomography perfusion (CTP) and computed tomography angiography (CTA) are valuable tools for diagnosing acute ischemic stroke (AIS). It is essential to obtain high-quality CTP and CTA images in short time. This study aimed to evaluate the image quality and diagnostic performance of brain CTP and CTA images generated from CTP reconstructed by a deep learning image reconstruction (DLIR) algorithm on patients with AIS. Methods The study prospectively enrolled 54 patients with suspected AIS undergoing non-contrast CT and CTP within 24 hours. CTP datasets were reconstructed with three levels of adaptive statistical iterative reconstruction-Veo algorithm [ASIR-V 0% with filtered back projection (FBP), ASIR-V 40%, and ASIR-V 80%] and three levels of DLIR, including low (DLIR-L), medium (DLIR-M), and high (DLIR-H). CTA images were generated using the CTP datasets at the peak arterial phase. Objective parameters including signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and noise reduction rate. Subjective evaluation was assessed according to Abels scoring system. Perfusion parameters and detection accuracy for infarction core lesions were evaluated. The objective and subjective image quality of CTA images were also evaluated. Results All reconstructions produced similar CT values (P>0.05). With the increase of ASIR-V and DLIR reconstruction strength, image noise decreased, while SNR and CNR increased for CTP images, especially in white matter. DLIR-H, DLIR-M, and ASIR-V80% yielded higher subjective scores than did ASIR-V40% and FBP. DLIR-H provided the highest noise reduction rate and detection accuracy. No significant difference was found in conventional parameters, the volume of infarct core, or ischemic penumbra among the 6 groups (P>0.05). The objective evaluation of reconstructed CTA images was comparable in DLIR-H, DLIR-M, and ASIR-V80% (P>0.05). The subjective scores of the DLIR-H and DLIR-M images were higher than those of the other groups, especially ASIR-V40% and FBP (P<0.05). Conclusions Compared with FBP and ASIR-V40%, DLIR-H, DLIR-M, and ASIR-V80% improved the overall image quality of CTP and CTA images to varying degrees. Furthermore, DLIR-H and DLIR-M showed the best performance. DLIR-H is the best choice in diagnosing AIS with improved detection accuracy for cerebral infarction. Reconstructing CTA images using CTP datasets could reduce contrast agent and radiation dose.
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Affiliation(s)
- Limin Lei
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yuhan Zhou
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaoxu Guo
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | | | - Xitong Zhao
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Hui Wang
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jinping Ma
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Songwei Yue
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Zaid Al-Kaylani AHA, Schuurmann RCL, Maathuis WD, Slart RHJA, de Vries JPPM, Bokkers RPH. Clinical Applications of Conebeam CTP Imaging in Cerebral Disease: A Systematic Review. AJNR Am J Neuroradiol 2023; 44:922-927. [PMID: 37414451 PMCID: PMC10411850 DOI: 10.3174/ajnr.a7930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 06/11/2023] [Indexed: 07/08/2023]
Abstract
BACKGROUND Perfusion imaging with multidetector CT is integral to the evaluation of patients presenting with ischemic stroke due to large-vessel occlusion. Using conebeam CT perfusion in a direct-to-angio approach could reduce workflow times and improve functional outcome. PURPOSE Our aim was to provide an overview of conebeam CT techniques for quantifying cerebral perfusion, their clinical applications, and validation. DATA SOURCES A systematic search was performed for articles published between January 2000 and October 2022 in which a conebeam CT imaging technique for quantifying cerebral perfusion in human subjects was compared against a reference technique. STUDY SELECTION Eleven articles were retrieved describing 2 techniques: dual-phase (n = 6) and multiphase (n = 5) conebeam CTP. DATA ANALYSIS Descriptions of the conebeam CT techniques and the correlations between them and the reference techniques were retrieved. DATA SYNTHESIS Appraisal of the quality and risk of bias of the included studies revealed little concern about bias and applicability. Good correlations were reported for dual-phase conebeam CTP; however, the comprehensiveness of its parameter is unclear. Multiphase conebeam CTP demonstrated the potential for clinical implementation due to its ability to produce conventional stroke protocols. However, it did not consistently correlate with the reference techniques. LIMITATIONS The heterogeneity within the available literature made it impossible to apply meta-analysis to the data. CONCLUSIONS The reviewed techniques show promise for clinical use. Beyond evaluating their diagnostic accuracy, future studies should address the practical challenges associated with implementing these techniques and the potential benefits for different ischemic diseases.
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Affiliation(s)
- A H A Zaid Al-Kaylani
- Department of Radiology (A.H.A.Z.A., R.H.J.A.S., R.P.H.B.), Medical Imaging Center
- Department of Surgery (A.H.A.Z.A., R.C.L.S., J.-P.M.P.d.V.), Division of Vascular Surgery
| | - R C L Schuurmann
- Department of Surgery (A.H.A.Z.A., R.C.L.S., J.-P.M.P.d.V.), Division of Vascular Surgery
| | - W D Maathuis
- Department of Biomedical Photonic Imaging (W.D.M., R.H.J.A.S.), Faculty of Science and Technology, University of Twente, Enschede, the Netherlands
| | - R H J A Slart
- Department of Radiology (A.H.A.Z.A., R.H.J.A.S., R.P.H.B.), Medical Imaging Center
- Department of Nuclear Medicine and Molecular Imaging (R.H.J.A.S.), University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
- Department of Biomedical Photonic Imaging (W.D.M., R.H.J.A.S.), Faculty of Science and Technology, University of Twente, Enschede, the Netherlands
| | - J-P P M de Vries
- Department of Surgery (A.H.A.Z.A., R.C.L.S., J.-P.M.P.d.V.), Division of Vascular Surgery
| | - R P H Bokkers
- Department of Radiology (A.H.A.Z.A., R.H.J.A.S., R.P.H.B.), Medical Imaging Center
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Takamura T, Hara S, Nariai T, Ikenouchi Y, Suzuki M, Taoka T, Ida M, Ishigame K, Hori M, Sato K, Kamagata K, Kumamaru K, Oishi H, Okamoto S, Araki Y, Uda K, Miyajima M, Maehara T, Inaji M, Tanaka Y, Naganawa S, Kawai H, Nakane T, Tsurushima Y, Onodera T, Nojiri S, Aoki S. Effect of Temporal Sampling Rate on Estimates of the Perfusion Parameters for Patients with Moyamoya Disease Assessed with Simultaneous Multislice Dynamic Susceptibility Contrast-enhanced MR Imaging. Magn Reson Med Sci 2023; 22:301-312. [PMID: 35296610 PMCID: PMC10449549 DOI: 10.2463/mrms.mp.2021-0162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 02/19/2022] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The effect of temporal sampling rate (TSR) on perfusion parameters has not been fully investigated in Moyamoya disease (MMD); therefore, this study evaluated the influence of different TSRs on perfusion parameters quantitatively and qualitatively by applying simultaneous multi-slice (SMS) dynamic susceptibility contrast-enhanced MR imaging (DSC-MRI). METHODS DSC-MRI datasets were acquired from 28 patients with MMD with a TSR of 0.5 s. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and time to maximum tissue residue function (Tmax) were calculated for eight TSRs ranging from 0.5 to 4.0 s in 0.5-s increments that were subsampled from a TSR of 0.5 s datasets. Perfusion measurements and volume for chronic ischemic (Tmax ≥ 2 s) and non-ischemic (Tmax < 2 s) areas for each TSR were compared to measurements with a TSR of 0.5 s, as was visual perfusion map analysis. RESULTS CBF, CBV, and Tmax values tended to be underestimated, whereas MTT and TTP values were less influenced, with a longer TSR. Although Tmax values were overestimated in the TSR of 1.0 s in non-ischemic areas, differences in perfusion measurements between the TSRs of 0.5 and 1.0 s were generally minimal. The volumes of the chronic ischemic areas with a TSR ≥ 3.0 s were significantly underestimated. In CBF and CBV maps, no significant deterioration was noted in image quality up to 3.0 and 2.5 s, respectively. The image quality of MTT, TTP, and Tmax maps for the TSR of 1.0 s was similar to that for the TSR of 0.5 s but was significantly deteriorated for the TSRs of ≥ 1.5 s. CONCLUSION In the assessment of MMD by SMS DSC-MRI, application of TSRs of ≥ 1.5 s may lead to deterioration of the perfusion measurements; however, that was less influenced in TSRs of ≤ 1.0 s.
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Affiliation(s)
- Tomohiro Takamura
- Department of Radiology, Shizuoka General Hospital, Shizuoka, Shizuoka, Japan
- Department of Radiology, Juntendo University, Tokyo, Japan
| | - Shoko Hara
- Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tadashi Nariai
- Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan
| | | | | | - Toshiaki Taoka
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Masahiro Ida
- Department of Radiology, Mito Medical Center, Higashiibaraki, Ibaraki, Japan
| | - Keiichi Ishigame
- Department of Radiology, Kenshinkai Tokyo Medical Clinic, Tokyo, Japan
| | - Masaaki Hori
- Department of Radiology, Juntendo University, Tokyo, Japan
- Department of Radiology, Toho University Omori Medical Center, Tokyo, Japan
| | - Kanako Sato
- Department of Radiology, Juntendo University, Tokyo, Japan
| | - Koji Kamagata
- Department of Radiology, Juntendo University, Tokyo, Japan
| | | | - Hidenori Oishi
- Department of Neurosurgery, Juntendo University, Tokyo, Japan
| | - Sho Okamoto
- Department of Neurosurgery, Nagoya University, Nagoya, Aichi, Japan
| | - Yoshio Araki
- Department of Neurosurgery, Nagoya University, Nagoya, Aichi, Japan
| | - Kenji Uda
- Department of Neurosurgery, Nagoya University, Nagoya, Aichi, Japan
| | - Masakazu Miyajima
- Department of Neurosurgery, Juntendo Tokyo Koto Geriatric Medical Center, Tokyo, Japan
| | - Taketoshi Maehara
- Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan
| | - Motoki Inaji
- Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yoji Tanaka
- Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shinji Naganawa
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Hisashi Kawai
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Toshiki Nakane
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | | | - Toshiyuki Onodera
- Department of Radiology, Tokyo Metropolitan Cancer Detection Center, Tokyo, Japan
| | - Shuko Nojiri
- Clinical Research and Trial Center, Juntendo Hospital, Tokyo, Japan
| | - Shigeki Aoki
- Department of Radiology, Juntendo University, Tokyo, Japan
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Ma G, Cao YZ, Shen GC, Lu SS, Zhang YX, Zhang Y, Shi HB, Xu XQ, Wu FY. CT perfusion with increased temporal sampling interval to predict target mismatch status in patients with acute ischemic stroke. Neuroradiology 2023; 65:105-111. [PMID: 35925438 DOI: 10.1007/s00234-022-03026-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/22/2022] [Indexed: 01/12/2023]
Abstract
PURPOSE To evaluate the feasibility of using CT perfusion (CTP) with increased temporal sampling interval to predict the target mismatch status in acute ischemic stroke (AIS) patients with anterior circular large-vessel occlusion (LVO). METHODS CTP with a sampling interval of 1.7 s (CTP1.7 s) was scanned in 77 AIS patients for pre-treatment evaluation. Simulated CTP data with sampling interval of 3.4 s (CTP3.4 s) or 5.1 s (CTP5.1 s) were reconstructed, respectively. Target mismatch was defined according to the EXTEND-IA (Extending the Time for Thrombolysis in Emergency Neurological Deficits-Intra-Arterial) and DEFUSE 3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke) trial criteria, respectively. Pearson correlation analysis, Mann-Whitney U test, Bland-Altman analysis, and chi-square test were used for statistical analysis as appropriate. RESULTS Significant correlations were found on the volume of ischemic core, hypo-perfused area, mismatch area, and ratio between CTP1.7 s and CTP3.4 s or CTP5.1 s (all p < 0.001). There was no significant difference on the volume of ischemic core, hypo-perfused area, mismatch area, and mismatch ratio between CTP1.7 s and CTP3.4 s or CTP5.1 s (all p > 0.05). Compared with CTP1.7 s, CTP3.4 s or CTP5.1 s showed comparable performance in predicting the target mismatch status in the AIS patients with LVO (both p > 0.05). CONCLUSIONS CTPs with increased temporal sampling intervals that lead to reduced radiation doses are feasible and may provide comparable performance in predicting target mismatch status in AIS patients with LVO.
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Affiliation(s)
- Gao Ma
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, No. 300, Guangzhou Rd., Nanjing, China
| | - Yue-Zhou Cao
- Department of Interventional Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Guang-Chen Shen
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, No. 300, Guangzhou Rd., Nanjing, China
| | - Shan-Shan Lu
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, No. 300, Guangzhou Rd., Nanjing, China
| | - Ya-Xi Zhang
- Shukun Network Technology Co., Ltd, Beijing, China
| | - Yu Zhang
- Shukun Network Technology Co., Ltd, Beijing, China
| | - Hai-Bin Shi
- Department of Interventional Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Xiao-Quan Xu
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, No. 300, Guangzhou Rd., Nanjing, China.
| | - Fei-Yun Wu
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, No. 300, Guangzhou Rd., Nanjing, China.
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Chung KJ, Khaw AV, Lee DH, Pandey S, Mandzia J, Lee TY. Low-dose CT Perfusion with Sparse-view Filtered Back Projection in Acute Ischemic Stroke. Acad Radiol 2022; 29:1502-1511. [PMID: 35300907 DOI: 10.1016/j.acra.2022.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 01/15/2022] [Accepted: 01/24/2022] [Indexed: 12/30/2022]
Abstract
RATIONALE AND OBJECTIVES Radiation dose associated with computed tomography (CT) perfusion (CTP) may discourage its use despite its added diagnostic benefit in quantifying ischemic lesion volume. Sparse-view CT reduces scan dose by acquiring fewer X-ray projections per gantry rotation but is contaminated by streaking artifacts using filtered back projection (FBP). We investigated the achievable dose reduction by sparse-view CTP with FBP without affecting CTP lesion volume estimations. MATERIALS AND METHODS Thirty-eight consecutive patients with acute ischemic stroke and CTP were included in this simulation study. CTP projection data was simulated by forward projecting original reconstructions with 984 views and adding Gaussian noise. Full-view (984 views) and sparse-view (492, 328, 246, and 164 views) CTP studies were simulated by FBP of simulated projection data. Cerebral blood flow (CBF) and time-to-maximum of the impulse residue function (Tmax) maps were generated by deconvolution for each simulated CTP study. Ischemic volumes were measured by CBF<30% relative to the contralateral hemisphere and Tmax > 6 s. Volume accuracy was evaluated with respect to the full-view CTP study by the Friedman test with post hoc multiplicity-adjusted pairwise tests and Bland-Altman analysis. RESULTS Friedman and multiplicity-adjusted pairwise tests indicated that 164-view CBF < 30%, 246- and 164-view Tmax > 6 s volumes were significantly different to full-view volumes (p < 0.001). Mean difference ± standard deviation (sparse minus full-view lesion volume) ranged from -1.0 ± 2.8 ml to -4.1 ± 11.7 ml for CBF < 30% and -2.9 ± 3.8 ml to -12.5 ± 19.9 ml for Tmax > 6 s from 492 to 164 views, respectively. CONCLUSION By ischemic volume accuracy, our study indicates that sparse-view CTP may allow dose reduction by up to a factor of 3.
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Affiliation(s)
- Kevin J Chung
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada; Robarts Research Institute and Lawson Health Research Institute, University of Western Ontario, 1151 Richmond Street N, London, ON N6A 5B7, Canada
| | - Alexander V Khaw
- Department of Clinical Neurological Sciences, University of Western Ontario, London, ON, Canada
| | - Donald H Lee
- Department of Medical Imaging, University of Western Ontario, London, ON, Canada
| | - Sachin Pandey
- Department of Medical Imaging, University of Western Ontario, London, ON, Canada
| | - Jennifer Mandzia
- Department of Clinical Neurological Sciences, University of Western Ontario, London, ON, Canada
| | - Ting-Yim Lee
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada; Robarts Research Institute and Lawson Health Research Institute, University of Western Ontario, 1151 Richmond Street N, London, ON N6A 5B7, Canada; Department of Medical Imaging, University of Western Ontario, London, ON, Canada.
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Zeng D, Zeng C, Zeng Z, Li S, Deng Z, Chen S, Bian Z, Ma J. Basis and current state of computed tomography perfusion imaging: a review. Phys Med Biol 2022; 67. [PMID: 35926503 DOI: 10.1088/1361-6560/ac8717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 08/04/2022] [Indexed: 12/30/2022]
Abstract
Computed tomography perfusion (CTP) is a functional imaging that allows for providing capillary-level hemodynamics information of the desired tissue in clinics. In this paper, we aim to offer insight into CTP imaging which covers the basics and current state of CTP imaging, then summarize the technical applications in the CTP imaging as well as the future technological potential. At first, we focus on the fundamentals of CTP imaging including systematically summarized CTP image acquisition and hemodynamic parameter map estimation techniques. A short assessment is presented to outline the clinical applications with CTP imaging, and then a review of radiation dose effect of the CTP imaging on the different applications is presented. We present a categorized methodology review on known and potential solvable challenges of radiation dose reduction in CTP imaging. To evaluate the quality of CTP images, we list various standardized performance metrics. Moreover, we present a review on the determination of infarct and penumbra. Finally, we reveal the popularity and future trend of CTP imaging.
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Affiliation(s)
- Dong Zeng
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Cuidie Zeng
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Zhixiong Zeng
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Sui Li
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Zhen Deng
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Sijin Chen
- Department of Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Zhaoying Bian
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Jianhua Ma
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
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Zhao C, Martin T, Shao X, Alger JR, Duddalwar V, Wang DJJ. Low Dose CT Perfusion With K-Space Weighted Image Average (KWIA). IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:3879-3890. [PMID: 32746131 PMCID: PMC7704693 DOI: 10.1109/tmi.2020.3006461] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
CTP (Computed Tomography Perfusion) is widely used in clinical practice for the evaluation of cerebrovascular disorders. However, CTP involves high radiation dose (≥~200mGy) as the X-ray source remains continuously on during the passage of contrast media. The purpose of this study is to present a low dose CTP technique termed K-space Weighted Image Average (KWIA) using a novel projection view-shared averaging algorithm with reduced tube current. KWIA takes advantage of k-space signal property that the image contrast is primarily determined by the k-space center with low spatial frequencies and oversampled projections. KWIA divides each 2D Fourier transform (FT) or k-space CTP data into multiple rings. The outer rings are averaged with neighboring time frames to achieve adequate signal-to-noise ratio (SNR), while the center region of k-space remains unchanged to preserve high temporal resolution. Reduced dose sinogram data were simulated by adding Poisson distributed noise with zero mean on digital phantom and clinical CTP scans. A physical CTP phantom study was also performed with different X-ray tube currents. The sinogram data with simulated and real low doses were then reconstructed with KWIA, and compared with those reconstructed by standard filtered back projection (FBP) and simultaneous algebraic reconstruction with regularization of total variation (SART-TV). Evaluation of image quality and perfusion metrics using parameters including SNR, CNR (contrast-to-noise ratio), AUC (area-under-the-curve), and CBF (cerebral blood flow) demonstrated that KWIA is able to preserve the image quality, spatial and temporal resolution, as well as the accuracy of perfusion quantification of CTP scans with considerable (50-75%) dose-savings.
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Zhang Y, Peng J, Zeng D, Xie Q, Li S, Bian Z, Wang Y, Zhang Y, Zhao Q, Zhang H, Liang Z, Lu H, Meng D, Ma J. Contrast-Medium Anisotropy-Aware Tensor Total Variation Model for Robust Cerebral Perfusion CT Reconstruction with Low-Dose Scans. IEEE TRANSACTIONS ON COMPUTATIONAL IMAGING 2020; 6:1375-1388. [PMID: 33313342 PMCID: PMC7731921 DOI: 10.1109/tci.2020.3023598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Perfusion computed tomography (PCT) is critical in detecting cerebral ischemic lesions. PCT examination with low-dose scans can effectively reduce radiation exposure to patients at the cost of degraded images with severe noise and artifacts. Tensor total variation (TTV) models are powerful tools that can encode the regional continuous structures underlying a PCT object. In a TTV model, the sparsity structures of the contrast-medium concentration (CMC) across PCT frames are assumed to be isotropic with identical and independent distribution. However, this assumption is inconsistent with practical PCT tasks wherein the sparsity has evident variations and correlations. Such modeling deviation hampers the performance of TTV-based PCT reconstructions. To address this issue, we developed a novel contrast-medium anisotropy-aware tensor total variation (CMAA-TTV) model to describe the intrinsic anisotropy sparsity of the CMC in PCT imaging tasks. Instead of directly on the difference matrices, the CMAA-TTV model characterizes sparsity on a low-rank subspace of the difference matrices which are calculated from the input data adaptively, thus naturally encoding the intrinsic variant and correlated anisotropy sparsity structures of the CMC. We further proposed a robust and efficient PCT reconstruction algorithm to improve low-dose PCT reconstruction performance using the CMAA-TTV model. Experimental studies using a digital brain perfusion phantom, patient data with low-dose simulation and clinical patient data were performed to validate the effectiveness of the presented algorithm. The results demonstrate that the CMAA-TTV algorithm can achieve noticeable improvements over state-of-the-art methods in low-dose PCT reconstruction tasks.
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Affiliation(s)
- Yuanke Zhang
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China, and also with the School of Information Science and Engineering, Qufu Normal University, Rizhao 276826, China
| | - Jiangjun Peng
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Dong Zeng
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
| | - Qi Xie
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Sui Li
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
| | - Zhaoying Bian
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
| | - Yongbo Wang
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
| | - Yong Zhang
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Qian Zhao
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Hao Zhang
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Zhengrong Liang
- Departments of Radiology and Biomedical Engineering, State University of New York at Stony Brook, NY 11794, USA
| | - Hongbing Lu
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China
| | - Deyu Meng
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jianhua Ma
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
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Rotkopf LT, Wiestler B, Preibisch C, Liesche-Starnecker F, Pyka T, Nörenberg D, Bette S, Gempt J, Thierfelder KM, Zimmer C, Huber T. The wavelet power spectrum of perfusion weighted MRI correlates with tumor vascularity in biopsy-proven glioblastoma samples. PLoS One 2020; 15:e0228030. [PMID: 31971966 PMCID: PMC6977746 DOI: 10.1371/journal.pone.0228030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 01/06/2020] [Indexed: 01/16/2023] Open
Abstract
Background Wavelet transformed reconstructions of dynamic susceptibility contrast (DSC) MR perfusion (wavelet-MRP) are a new and elegant way of visualizing vascularization. Wavelet-MRP maps yield a clear depiction of hypervascular tumor regions, as recently shown. Objective The aim of this study was to elucidate a possible connection of the wavelet-MRP power spectrum in glioblastoma (GBM) with local vascularity and cell proliferation. Methods For this IRB-approved study 12 patients (63.0+/-14.9y; 7m) with histologically confirmed IDH-wildtype GBM were included. Target regions for biopsies were prospectively marked on tumor regions as seen on preoperative 3T MRI. During subsequent neurosurgical tumor resection 43 targeted biopsies were taken from these target regions, of which all 27 matching samples were analyzed. All specimens were immunohistochemically analyzed for endothelial cell marker CD31 and proliferation marker Ki67 and correlated to the wavelet-MRP power spectrum as derived from DSC perfusion weighted imaging. Results There was a strong correlation between wavelet-MRP power spectrum (median = 4.41) and conventional relative cerebral blood volume (median = 5.97 ml/100g) in Spearman's rank-order correlation (κ = .83, p < .05). In a logistic regression model, the wavelet-MRP power spectrum showed a significant correlation to CD31 dichotomized to no or present staining (p = .04), while rCBV did not show a significant correlation to CD31 (p = .30). No significant association between Ki67 and rCBV or wavelet-MRP was found (p = .62 and p = .70, respectively). Conclusion The wavelet-MRP power spectrum derived from existing DSC-MRI data might be a promising new surrogate for tumor vascularity in GBM.
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Affiliation(s)
- Lukas T. Rotkopf
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
- * E-mail:
| | - Benedikt Wiestler
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Christine Preibisch
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | | | - Thomas Pyka
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Dominik Nörenberg
- Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Stefanie Bette
- Department of Diagnostic and Interventional Radiology and Neuroradiology, Universitaetsklinikum Augsburg, Augsburg, Germany
| | - Jens Gempt
- Department of Neurosurgery, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Kolja M. Thierfelder
- Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany
| | - Claus Zimmer
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Thomas Huber
- Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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11
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Diagnostic accuracy of flat-panel computed tomography in assessing cerebral perfusion in comparison with perfusion computed tomography and perfusion magnetic resonance: a systematic review. Neuroradiology 2019; 61:1457-1468. [PMID: 31523757 PMCID: PMC6848034 DOI: 10.1007/s00234-019-02285-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/26/2019] [Indexed: 12/09/2022]
Abstract
Purpose Flat-panel computed tomography (FP-CT) is increasingly available in angiographic rooms and hybrid OR’s. Considering its easy access, cerebral imaging using FP-CT is an appealing modality for intra-procedural applications. The purpose of this systematic review is to assess the diagnostic accuracy of FP-CT compared with perfusion computed tomography (CTP) and perfusion magnetic resonance (MRP) in cerebral perfusion imaging. Methods We performed a systematic literature search in the Cochrane Library, MEDLINE, Embase, and Web of Science up to June 2019 for studies directly comparing FP-CT with either CTP or MRP in vivo. Methodological quality was assessed using the QUADAS-2 tool. Data on diagnostic accuracy was extracted and pooled if possible. Results We found 11 studies comparing FP-CT with CTP and 5 studies comparing FP-CT with MRP. Most articles were pilot or feasibility studies, focusing on scanning and contrast protocols. All patients studied showed signs of cerebrovascular disease. Half of the studies were animal trials. Quality assessment showed unclear to high risks of bias and low concerns regarding applicability. Five studies reported on diagnostic accuracy; FP-CT shows good sensitivity (range 0.84–1.00) and moderate specificity (range 0.63–0.88) in detecting cerebral blood volume (CBV) lesions. Conclusions Even though FP-CT provides similar CBV values and reconstructed blood volume maps as CTP in cerebrovascular disease, additional studies are required in order to reliably compare its diagnostic accuracy with cerebral perfusion imaging. Electronic supplementary material The online version of this article (10.1007/s00234-019-02285-y) contains supplementary material, which is available to authorized users.
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12
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van Ommen F, Kauw F, Bennink E, Dankbaar JW, Viergever MA, de Jong HWAM. Effect of prolonged acquisition intervals for CT-perfusion analysis methods in patients with ischemic stroke. Med Phys 2019; 46:3156-3164. [PMID: 31049968 PMCID: PMC6851872 DOI: 10.1002/mp.13559] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 04/11/2019] [Accepted: 04/24/2019] [Indexed: 12/16/2022] Open
Abstract
Introduction The limited axial coverage of many computed tomography (CT) scanners poses a high risk on false negative findings in cerebral CT‐perfusion (CTP) imaging. Axial coverage may be increased by moving the table back and forth during image acquisition. However, this method often increases the acquisition interval between CT frames, which may influence the CTP analysis. In this study, we evaluated the influence of different acquisition intervals on quantitative perfusion maps and infarct volumes by analyzing patient data with three CTP analysis methods. Methods CT‐perfusion data from 25 patients with ischemic stroke were used for this study. The acquisition interval was synthetically reduced from 1 to 5 s before calculating perfusion values, which included cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). The color scaling of the perfusion was scaled such that the mean perfusion value had the same color‐coding as the mean perfusion in the 1 s reference. Also, infarct core and penumbra volumes (summary map) were calculated using default thresholds of CBV and relative MTT (rMTT). The original, 1 s acquisition interval scan served as the reference standard. A commercial block‐circulant singular value decomposition (bSVD) based method (ISP; Philips Healthcare), a non‐commercial bSVD method, and a non‐linear regression (NLR) model‐based method were evaluated. Results Cerebral blood volume values generated with bSVD and NLR were not significantly different from the reference standard, while ISP showed significant differences for acquisition intervals of 3 and 4 s. MTT and CBF values generated with bSVD and ISP were significantly different for all acquisition intervals, whereas NLR did not show any significant differences. Calibrated perfusion maps were able to distinguish healthy from infarcted tissue up to an acquisition interval of 5 s for all methods. The infarct core volumes were significantly different for acquisition intervals of 2 (NLR) and 3 s (bSVD and ISP) or greater. For the penumbra volumes, NLR showed no significant differences, while bSVD and ISP showed significant differences for the 5 s interval and for all intervals, respectively. Visual inspection of the summary maps indicated minor differences between the reference standard and acquisition intervals of 4 s or less (ISP) and 5 s or less (bSVD and NLR). Conclusion Altering the acquisition interval may introduce a bias in the perfusion parameters. Calibration of the visualization of the perfusion maps with increasing acquisition intervals allowed distinction between healthy and infarcted tissue. Infarct volumes based on relative MTT can be influenced by the acquisition interval, but visual inspection of the summary maps indicated minor differences between the reference standard and acquisition intervals up to 4 (ISP) and 5 s (bSVD and NLR). Taken together, axial coverage can be increased by prolonging the acquisition interval up to 5 s depending on the perfusion analysis.
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Affiliation(s)
- Fasco van Ommen
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, the Netherlands.,Image Sciences Institute, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Frans Kauw
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Edwin Bennink
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, the Netherlands.,Image Sciences Institute, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Jan Willem Dankbaar
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Max A Viergever
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Hugo W A M de Jong
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, the Netherlands.,Image Sciences Institute, University Medical Center Utrecht, Utrecht, the Netherlands
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13
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Xiao Y, Liu P, Liang Y, Stolte S, Sanelli P, Gupta A, Ivanidze J, Fang R. STIR-Net: Deep Spatial-Temporal Image Restoration Net for Radiation Reduction in CT Perfusion. Front Neurol 2019; 10:647. [PMID: 31297079 PMCID: PMC6607281 DOI: 10.3389/fneur.2019.00647] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 06/03/2019] [Indexed: 02/04/2023] Open
Abstract
Computed Tomography Perfusion (CTP) imaging is a cost-effective and fast approach to provide diagnostic images for acute stroke treatment. Its cine scanning mode allows the visualization of anatomic brain structures and blood flow; however, it requires contrast agent injection and continuous CT scanning over an extended time. In fact, the accumulative radiation dose to patients will increase health risks such as skin irritation, hair loss, cataract formation, and even cancer. Solutions for reducing radiation exposure include reducing the tube current and/or shortening the X-ray radiation exposure time. However, images scanned at lower tube currents are usually accompanied by higher levels of noise and artifacts. On the other hand, shorter X-ray radiation exposure time with longer scanning intervals will lead to image information that is insufficient to capture the blood flow dynamics between frames. Thus, it is critical for us to seek a solution that can preserve the image quality when the tube current and the temporal frequency are both low. We propose STIR-Net in this paper, an end-to-end spatial-temporal convolutional neural network structure, which exploits multi-directional automatic feature extraction and image reconstruction schema to recover high-quality CT slices effectively. With the inputs of low-dose and low-resolution patches at different cross-sections of the spatio-temporal data, STIR-Net blends the features from both spatial and temporal domains to reconstruct high-quality CT volumes. In this study, we finalize extensive experiments to appraise the image restoration performance at different levels of tube current and spatial and temporal resolution scales.The results demonstrate the capability of our STIR-Net to restore high-quality scans at as low as 11% of absorbed radiation dose of the current imaging protocol, yielding an average of 10% improvement for perfusion maps compared to the patch-based log likelihood method.
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Affiliation(s)
- Yao Xiao
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Peng Liu
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Yun Liang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Skylar Stolte
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Pina Sanelli
- Department of Radiology, Weill Cornell Medical College, New York, NY, United States
- Imaging Clinical Effectiveness and Outcomes Research, Department of Radiology, Northwell Health, Manhasset, NY, United States
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, United States
- Center for Health Innovations and Outcomes Research, Feinstein Institute for Medical Research, Manhasset, NY, United States
| | - Ajay Gupta
- Department of Radiology, Weill Cornell Medical College, New York, NY, United States
| | - Jana Ivanidze
- Department of Radiology, Weill Cornell Medical College, New York, NY, United States
| | - Ruogu Fang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
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14
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Karwacki GM, Vögele S, Blackham KA. Dose reduction in perfusion CT in stroke patients by lowering scan frequency does not affect automatically calculated infarct core volumes. J Neuroradiol 2019; 46:351-358. [PMID: 31034899 DOI: 10.1016/j.neurad.2019.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 04/04/2019] [Accepted: 04/09/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND AND PURPOSE CT Perfusion technique (CTP) is a quantitative, easily performed, accepted and reliable method for detection of ischemic brain changes. Based on calculated parameters, the size of ischemic penumbra and irreversibly damaged infarct core can be determined which helps guide treatment decisions. However, due to the dynamic nature of the CTP study, it is dose intensive. This study determines the consequences of retrospectively reducing the number of scans in the dynamic acquisition by half on the volume of the automatically calculated infarct core (non-viable tissue) and penumbra (tissue at risk) volumes. Our hypothesis was that equivalent volumetric information could be obtained at a substantial dose savings. MATERIALS AND METHODS Fifty one consecutive patients with occlusion of M1 and/or M2 segment of the middle cerebral artery and ischemic stroke proven by follow-up MRI were included. CTP scans were first analyzed in a standard fashion and automatically generated volumes measured in milliliters were recorded in a database. A second analysis was conducted after removing every second data acquisition from the sequential CTP scans. Automatic volume measurements were repeated, recorded and compared to the initial values obtained using the full dataset. RESULTS The two CTP protocols were statistically equivalent pertaining to automatic infarct core volume calculation but a case-by-case analysis revealed substantial overestimation in some cases. CONCLUSION Reduction of radiation exposure in CTP without objective loss of accuracy of automatically calculated infarct core volume is feasible but might lead to clinically relevant infarct core overestimation in individual cases.
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Affiliation(s)
- Grzegorz Marek Karwacki
- University Hospital Basel, University of Basel, clinic of radiology and nuclear medicine, Basel, Switzerland.
| | - Stephan Vögele
- University Hospital Basel, University of Basel, clinic of radiology and nuclear medicine, Basel, Switzerland
| | - Kristine Ann Blackham
- University Hospital Basel, University of Basel, clinic of radiology and nuclear medicine, Basel, Switzerland
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15
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Radiation dose reduction in perfusion CT imaging of the brain using a 256-slice CT: 80 mAs versus 160 mAs. Clin Imaging 2018; 50:188-193. [DOI: 10.1016/j.clinimag.2018.03.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 03/12/2018] [Accepted: 03/29/2018] [Indexed: 11/21/2022]
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16
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Afat S, Brockmann C, Nikoubashman O, Müller M, Thierfelder KM, Kunz WG, Haberland U, Brockmann MA, Nikolaou K, Wiesmann M, Othman AE. Diagnostic performance of different perfusion algorithms for the detection of angiographical spasm. J Neuroradiol 2018; 45:290-294. [PMID: 29412162 DOI: 10.1016/j.neurad.2017.12.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 06/16/2017] [Accepted: 12/14/2017] [Indexed: 10/18/2022]
Abstract
PURPOSE To assess the diagnostic utility of different perfusion algorithms for the detection of angiographical terial spasm. METHOD During a 2-year period, 45 datasets from 29 patients (54.2±10,75y, 20F) with suspected cerebral vasospasm after aneurysmal subarachnoid hemorrhage were included. Volume Perfusion CT (VPCT), Non-enhanced CT (NCT) and angiography were performed within 6hours post-ictus. Perfusion maps were generated using a maximum slope (MS) and a deconvolution-based approach (DC). Two blinded neuroradiologists independently evaluated MS and DC maps regarding vasospasm-related perfusion impairment on a 3-point Likert-scale (0=no impairment, 1=impairment affecting <50%, 2=impairment affecting >50% of vascular territory). A third independent neuroradiologist assessed angiography for presence and severity of arterial narrowing on a 3-point Likert scale (0=no narrowing, 1=narrowing affecting <50%, 2=narrowing affecting>50% of artery diameter). MS and DC perfusion maps were evaluated regarding diagnostic accuracy for angiographical arterial spasm with angiography as reference standard. Correlation analysis of angiography findings with both MS and DC perfusion maps was additionally performed. Furthermor, the agreement between MS and DC and inter-reader agreement was assessed. RESULTS DC maps yielded significantly higher diagnostic accuracy than MS perfusion maps (DC:AUC=.870; MS:AUC=.805; P=0.007) with higher sensitivity for DC compared to MS (DC:sensitivity=.758; MS:sensitivity=.625). DC maps revealed stronger correlation with angiography than MS (DC: R=.788; MS: R=694;=<0.001). MS and DC showed substantial agreement (Kappa=.626). Regarding inter-reader analysis, (almost) perfect inter-reader agreement was observed for both MS and DC maps (Kappa≥981). CONCLUSION DC yields significantly higher diagnostic accuracy for the detection of angiographic arterial spasm and higher correlation with angiographic findings compared to MS.
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Affiliation(s)
- Saif Afat
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074 Aachen, Germany
| | - Carolin Brockmann
- Department of Neuroradiology, University Hospital Mainz, 55131 Mainz, Germany
| | - Omid Nikoubashman
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074 Aachen, Germany; Department of Diagnostic and Interventional Radiology, RWTH Aachen University, 52074 Aachen, Germany
| | - Marguerite Müller
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074 Aachen, Germany
| | - Kolja M Thierfelder
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - Wolfgang G Kunz
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 Munich, Germany
| | | | - Marc A Brockmann
- Department of Neuroradiology, University Hospital Mainz, 55131 Mainz, Germany
| | - Konstantin Nikolaou
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076 Tübingen, Germany
| | - Martin Wiesmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074 Aachen, Germany
| | - Ahmed E Othman
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074 Aachen, Germany; Siemens Healthcare GmbH, 91052 Forchheim, Germany.
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17
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Quantification of the Effect of Shuttling on Computed Tomography Perfusion Parameters by Investigation of Aortic Inputs on Different Table Positions From Shuttle-Mode Scans of Lung and Liver Tumors. J Comput Assist Tomogr 2017; 42:357-364. [PMID: 29189398 DOI: 10.1097/rct.0000000000000686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The aim of this study was to quantify the effect of shuttling on computed tomography perfusion (CTp) parameters derived from shuttle-mode body CT images using aortic inputs from different table positions. METHODS Axial shuttle-mode CT scans were acquired from 6 patients (10 phases, 2 nonoverlapping table positions 1.4 seconds apart) after contrast agent administration. Artifacts resulting from the shuttling motion were corrected with nonrigid registration before computing CTp maps from 4 aortic levels chosen from the most superior and inferior slices of each table position scan. The effect of shuttling on CTp parameters was estimated by mean differences in mappings obtained from aortic inputs in different table positions. Shuttling effect was also quantified using 95% limits of agreement of CTp parameter differences within-table and between-table aortic positions from the interaortic mean CTp values. RESULTS Blood flow, permeability surface, and hepatic arterial fraction differences were insignificant (P > 0.05) for both within-table and between-table comparisons. The 95% limits of agreement for within-table blood volume (BV) value deviations obtained from lung tumor regions were less than 4.7% (P = 0.18) compared with less than 12.2% (P = 0.003) for between-table BV value deviations. The 95% limits of agreement of within-table deviations for liver tumor regions were less than 1.9% (P = 0.55) for BV and less than 3.2% (P = 0.23) for mean transit time, whereas between-table BV and mean transit time deviations were less than 11.7% (P < 0.01) and less than 14.6% (P < 0.01), respectively. Values for normal liver tissue regions were concordant. CONCLUSIONS Computed tomography perfusion parameters acquired from aortic levels within-table positions generally yielded higher agreement than mappings obtained from aortic levels between-table positions indicating differences due to shuttling effect.
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18
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Takamura T, Hori M, Kamagata K, Kumamaru KK, Irie R, Hagiwara A, Hamasaki N, Aoki S. Slice-accelerated gradient-echo echo planar imaging dynamic susceptibility contrast-enhanced MRI with blipped CAIPI: effect of increasing temporal resolution. Jpn J Radiol 2017; 36:40-50. [PMID: 29086345 DOI: 10.1007/s11604-017-0695-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 10/13/2017] [Indexed: 01/02/2023]
Abstract
PURPOSE To assess the influence of high temporal resolution on the perfusion measurements and image quality of perfusion maps, by applying simultaneous-multi-slice acquisition (SMS) dynamic susceptibility contrast-enhanced (DSC) magnetic resonance imaging (MRI). MATERIALS AND METHODS DSC-MRI data using SMS gradient-echo echo planar imaging sequences in 10 subjects with no intracranial abnormalities were retrospectively analyzed. Three additional data sets with temporal resolution of 1.0, 1.5, and 2.0 s were created from the raw data sets of 0.5 s. Cerebral blood flow (CBF), cerebral blood volume, mean transit time (MTT), time to peak (TTP), and time to maximum tissue residue function (T max) measurements were performed, as was visual perfusion map analysis. The perfusion parameter for temporal resolution of 0.5 s (reference) was compared with each synthesized perfusion parameter. RESULTS CBF, MTT, and TTP values at temporal resolutions of 1.5 and 2.0 s differed significantly from the reference. The image quality of MTT, TTP, and T max maps deteriorated with decreasing temporal resolution. CONCLUSION The temporal resolution of DSC-MRI influences perfusion parameters and SMS DSC-MRI provides better image quality for MTT, TTP, and T max maps.
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Affiliation(s)
- Tomohiro Takamura
- Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Masaaki Hori
- Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Koji Kamagata
- Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Kanako K Kumamaru
- Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Ryusuke Irie
- Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Akifumi Hagiwara
- Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
- Department of Radiology, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Nozomi Hamasaki
- Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Shigeki Aoki
- Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
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Kasasbeh AS, Christensen S, Straka M, Mishra N, Mlynash M, Bammer R, Albers GW, Lansberg MG. Optimal Computed Tomographic Perfusion Scan Duration for Assessment of Acute Stroke Lesion Volumes. Stroke 2016; 47:2966-2971. [PMID: 27895299 DOI: 10.1161/strokeaha.116.014177] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/18/2016] [Accepted: 09/06/2016] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE The minimal scan duration needed to obtain reliable lesion volumes with computed tomographic perfusion (CTP) has not been well established in the literature. METHODS We retrospectively assessed the impact of gradual truncation of the scan duration on acute ischemic lesion volume measurements. For each scan, we identified its optimal scan time, defined as the shortest scan duration that yields measurements of the ischemic lesion volumes similar to those obtained with longer scanning, and the relative height of the fitted venous output function at its optimal scan time. RESULTS We analyzed 70 computed tomographic perfusion scans of acute stroke patients. An optimal scan time could not be determined in 11 scans (16%). For the other 59 scans, the median optimal scan time was 32.7 seconds (90th percentile 52.6 seconds; 100th percentile 68.9 seconds), and the median relative height of the fitted venous output function at the optimal scan times was 0.39 (90th percentile 0.02; 100th percentile 0.00). On the basis of a linear model, the optimal scan time was T0 plus 1.6 times the width of the venous output function (P<0.001; R2=0.49). CONCLUSIONS This study shows how the optimal duration of a computed tomographic perfusion scan relates to the arrival time and width of the contrast bolus. This knowledge can be used to optimize computed tomographic perfusion scan protocols and to determine whether a scan is of sufficient duration. Provided a baseline (T0) of 10 seconds, a total scan duration of 60 to 70 seconds, which includes the entire downslope of the venous output function in most patients, is recommended.
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Affiliation(s)
- Aimen S Kasasbeh
- From the Stanford Stroke Center, Stanford University Medical Center, Palo Alto, CA
| | - Søren Christensen
- From the Stanford Stroke Center, Stanford University Medical Center, Palo Alto, CA
| | - Matus Straka
- From the Stanford Stroke Center, Stanford University Medical Center, Palo Alto, CA
| | - Nishant Mishra
- From the Stanford Stroke Center, Stanford University Medical Center, Palo Alto, CA
| | - Michael Mlynash
- From the Stanford Stroke Center, Stanford University Medical Center, Palo Alto, CA
| | - Roland Bammer
- From the Stanford Stroke Center, Stanford University Medical Center, Palo Alto, CA
| | - Gregory W Albers
- From the Stanford Stroke Center, Stanford University Medical Center, Palo Alto, CA
| | - Maarten G Lansberg
- From the Stanford Stroke Center, Stanford University Medical Center, Palo Alto, CA.
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Othman AE, Afat S, Nikoubashman O, Müller M, Schubert GA, Bier G, Brockmann MA, Wiesmann M, Brockmann C. Volume perfusion CT imaging of cerebral vasospasm: diagnostic performance of different perfusion maps. Neuroradiology 2016; 58:787-92. [PMID: 27194077 DOI: 10.1007/s00234-016-1695-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/03/2016] [Indexed: 10/21/2022]
Abstract
INTRODUCTION In this study, we aimed to evaluate the diagnostic performance of different volume perfusion CT (VPCT) maps regarding the detection of cerebral vasospasm compared to angiographic findings. METHODS Forty-one datasets of 26 patients (57.5 ± 10.8 years, 18 F) with subarachnoid hemorrhage and suspected cerebral vasospasm, who underwent VPCT and angiography within 6 h, were included. Two neuroradiologists independently evaluated the presence and severity of vasospasm on perfusion maps on a 3-point Likert scale (0-no vasospasm, 1-vasospasm affecting <50 %, 2-vasospasm affecting >50 % of vascular territory). A third neuroradiologist independently assessed angiography for the presence and severity of vasospasm on a 3-point Likert scale (0-no vasospasm, 1-vasospasm affecting < 50 %, 2-vasospasm affecting > 50 % of vessel diameter). Perfusion maps of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time to drain (TTD) were evaluated regarding diagnostic accuracy for cerebral vasospasm with angiography as reference standard. Correlation analysis of vasospasm severity on perfusion maps and angiographic images was performed. Furthermore, inter-reader agreement was assessed regarding findings on perfusion maps. RESULTS Diagnostic accuracy for TTD and MTT was significantly higher than for all other perfusion maps (TTD, AUC = 0.832; MTT, AUC = 0.791; p < 0.001). TTD revealed higher sensitivity than MTT (p = 0.007). The severity of vasospasm on TTD maps showed significantly higher correlation levels with angiography than all other perfusion maps (p ≤ 0.048). Inter-reader agreement was (almost) perfect for all perfusion maps (kappa ≥ 0.927). CONCLUSION The results of this study indicate that TTD maps have the highest sensitivity for the detection of cerebral vasospasm and highest correlation with angiography regarding the severity of vasospasm.
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Affiliation(s)
- Ahmed E Othman
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany. .,Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany.
| | - Saif Afat
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
| | - Omid Nikoubashman
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
| | - Marguerite Müller
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
| | | | - Georg Bier
- Department for Diagnostic and Interventional Neuroradiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Tübingen, Germany
| | - Marc A Brockmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany.,Department of Neuroradiology, University Hospital Mainz, Mainz, Germany
| | - Martin Wiesmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
| | - Carolin Brockmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
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Lin CF, Hsu SPC, Lin CJ, Guo WY, Liao CH, Chu WF, Hung SC, Shih YS, Lin YT. Prolonged Cerebral Circulation Time Is the Best Parameter for Predicting Vasospasm during Initial CT Perfusion in Subarachnoid Hemorrhagic Patients. PLoS One 2016; 11:e0151772. [PMID: 26986626 PMCID: PMC4795708 DOI: 10.1371/journal.pone.0151772] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 03/03/2016] [Indexed: 12/03/2022] Open
Abstract
Purpose We sought to imitate angiographic cerebral circulation time (CCT) and create a similar index from baseline CT perfusion (CTP) to better predict vasospasm in patients with subarachnoid hemorrhage (SAH). Methods Forty-one SAH patients with available DSA and CTP were retrospectively included. The vasospasm group was comprised of patients with deterioration in conscious functioning and newly developed luminal narrowing; remaining cases were classified as the control group. The angiography CCT (XA-CCT) was defined as the difference in TTP (time to peak) between the selected arterial ROIs and the superior sagittal sinus (SSS). Four arterial ROIs were selected to generate four corresponding XA-CCTs: the right and left anterior cerebral arteries (XA-CCTRA2 and XA-CCTLA2) and right- and left-middle cerebral arteries (XA-CCTRM2 and XA-CCTLM2). The CCTs from CTP (CT-CCT) were defined as the differences in TTP from the corresponding arterial ROIs and the SSS. Correlations of the different CCTs were calculated and diagnostic accuracy in predicting vasospasm was evaluated. Results Intra-class correlations ranged from 0.96 to 0.98. The correlations of XA-CCTRA2, XA-CCTRM2, XA-CCTLA2, and XA-CCTLM2 with the corresponding CT-CCTs were 0.64, 0.65, 0.53, and 0.68, respectively. All CCTs were significantly prolonged in the vasospasm group (5.8–6.4 s) except for XA-CCTLA2. CT-CCTA2 of 5.62 was the optimal cut-off value for detecting vasospasm with a sensitivity of 84.2% and specificity 82.4% Conclusion CT-CCTs can be used to interpret cerebral flow without deconvolution algorithms, and outperform both MTT and TTP in predicting vasospasm risk. This finding may help facilitate management of patients with SAH.
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Affiliation(s)
- Chun Fu Lin
- Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Sanford P. C. Hsu
- Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chung Jung Lin
- Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Wan Yuo Guo
- Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
| | - Chih Hsiang Liao
- Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Wei Fa Chu
- Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Sheng Che Hung
- Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yang Shin Shih
- Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yen Tzu Lin
- Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
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Image quality, radiation dose and diagnostic accuracy of 70 kVp whole brain volumetric CT perfusion imaging: a preliminary study. Eur Radiol 2016; 26:4184-4193. [DOI: 10.1007/s00330-016-4225-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 01/02/2016] [Accepted: 01/15/2016] [Indexed: 11/30/2022]
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Radiation dose reduction in perfusion CT imaging of the brain: A review of the literature. J Neuroradiol 2016; 43:1-5. [DOI: 10.1016/j.neurad.2015.06.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 06/04/2015] [Accepted: 06/10/2015] [Indexed: 11/30/2022]
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Othman AE, Afat S, Brockmann C, Nikoubashman O, Bier G, Brockmann MA, Nikolaou K, Tai JH, Yang ZP, Kim JH, Wiesmann M. Low-Dose Volume-Perfusion CT of the Brain: Effects of Radiation Dose Reduction on Performance of Perfusion CT Algorithms. Clin Neuroradiol 2015; 27:311-318. [PMID: 26669592 DOI: 10.1007/s00062-015-0489-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/30/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE We aimed to compare different computed tomography (CT) perfusion post-processing algorithms regarding image quality of perfusion maps from low-dose volume perfusion CT (VPCT) and their diagnostic performance regarding the detection of ischemic brain lesions. METHODS AND MATERIALS We included VPCT data of 21 patients with acute stroke (onset < 6h), which were acquired at 80 kV and 180 mAs. Low-dose VPCT datasets with 72 mAs (40 % of original dose) were generated using realistic low-dose simulation. Perfusion maps (cerebral blood volume (CBV); cerebral blood flow (CBF) from original and low-dose datasets were generated using two different commercially available post-processing methods: deconvolution-based method (DC) and maximum slope algorithm (MS). The resulting DC and MS perfusion maps were compared regarding perfusion values, signal-to-noise ratio (SNR) as well as image quality and diagnostic accuracy as rated by two blinded neuroradiologists. RESULTS Quantitative perfusion parameters highly correlated for both algorithms and both dose levels (r ≥ 0.613, p < 0.001). Regarding SNR levels and image quality of the CBV maps, no significant differences between DC and MS were found (p ≥ 0.683). Low-dose MS CBF maps yielded significantly higher SNR levels (p < 0.001) and quality scores (p = 0.014) than those of DC. Low-dose CBF and CBV maps from both DC and MS yielded high sensitivity and specificity for the detection of ischemic lesions (sensitivity ≥ 0.82, specificity ≥ 0.90). CONCLUSION Our results indicate that both methods produce diagnostically sufficient perfusion maps from simulated low-dose VPCT. However, MS produced CBF maps with significantly higher image quality and SNR than DC, indicating that MS might be more suitable for low-dose VPCT imaging.
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Affiliation(s)
- A E Othman
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany.,Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - S Afat
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - C Brockmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - O Nikoubashman
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - G Bier
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - M A Brockmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - K Nikolaou
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - J H Tai
- Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, 433-270, Suwon, South Korea
| | - Z P Yang
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, 433-270, Suwon, South Korea
| | - J H Kim
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, 433-270, Suwon, South Korea. .,Department of Radiology, Seoul National University College of Medicine, 101 Daehak-Ro, Chongno-gu, 110-744, Seoul, South Korea. .,Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, 433-270, Suwon, South Korea.
| | - M Wiesmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
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Comparison of Imaging Selection Criteria for Intra-Arterial Thrombectomy in Acute Ischemic Stroke with Advanced CT. Eur Radiol 2015; 26:2974-81. [DOI: 10.1007/s00330-015-4141-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/30/2015] [Accepted: 11/24/2015] [Indexed: 10/22/2022]
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26
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Bricout N, Estrade L, Boustia F, Kalsoum E, Pruvo JP, Leclerc X. Reduced-dose CT protocol for the assessment of cerebral vasospasm. Neuroradiology 2015; 57:1211-8. [PMID: 26315026 DOI: 10.1007/s00234-015-1585-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 08/19/2015] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Despite the increased radiation dose, multimodal CT including noncontrast CT (NCT), CT angiography (CTA), and perfusion CT (PCT) remains a useful tool for the diagnosis of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH). The aim of this study was to assess the radiation dose and the image quality between a standard-dose and a reduced-dose multimodal CT protocol. METHODS The study group consisted of 26 aSAH patients with a suspicion of DCI on clinical examination and transcranial doppler. Two different CT protocols were used: a standard-dose protocol (NCT 120 kV, 350 mAs; CTA 100 kV, 250 mAs; PCT 80 kV, 200 mAs) from August 2011 to October 2013 (n = 13) and a reduced-dose protocol (NCT 100 kV, 400 mAs; CTA 100 kV, 220 mAs; PCT 80 kV, 180 mAs) from November 2013 to May 2014 (n = 13). Dose-length product (DLP), effective dose, volume CT dose index (CTDI), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and overall image quality were determined for each examination. RESULTS The overall image quality was judged as good or excellent in all cases. The reduced-dose protocol allowed a 15 % decrease in both the median total DLP (2438 vs 2898 mGy cm, p < 0.0001) and the effective dose as well as a significant decrease in median CTDI of 23, 31, and 10 % for NCT, CTA, and CTP, respectively. This dose reduction did not result in significant alteration of SNR (except for NCT) or CNR between groups. CONCLUSION The present study showed that the reduced-dose multimodal CT protocol enabled a significant reduction of radiation dose without image quality impairment.
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Affiliation(s)
- N Bricout
- Department of Neuroradiology, Université Lille Nord de France, Hôpital Roger Salengro, CHRU de Lille, Avenue Emile-Laine, 59037, Lille cedex, France.
| | - L Estrade
- Department of Neuroradiology, Université Lille Nord de France, Hôpital Roger Salengro, CHRU de Lille, Avenue Emile-Laine, 59037, Lille cedex, France
| | - F Boustia
- Department of Neuroradiology, Université Lille Nord de France, Hôpital Roger Salengro, CHRU de Lille, Avenue Emile-Laine, 59037, Lille cedex, France
| | - E Kalsoum
- Department of Neuroradiology, Université Lille Nord de France, Hôpital Roger Salengro, CHRU de Lille, Avenue Emile-Laine, 59037, Lille cedex, France
| | - J P Pruvo
- Department of Neuroradiology, Université Lille Nord de France, Hôpital Roger Salengro, CHRU de Lille, Avenue Emile-Laine, 59037, Lille cedex, France
| | - X Leclerc
- Department of Neuroradiology, Université Lille Nord de France, Hôpital Roger Salengro, CHRU de Lille, Avenue Emile-Laine, 59037, Lille cedex, France
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Ng CS, Hobbs BP, Wei W, Anderson EF, Herron DH, Yao JC, Chandler AG. Effect on perfusion values of sampling interval of computed tomographic perfusion acquisitions in neuroendocrine liver metastases and normal liver. J Comput Assist Tomogr 2015; 39:373-82. [PMID: 25626401 DOI: 10.1097/rct.0000000000000212] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study aimed to assess the effects of sampling interval (SI) of computed tomographic (CT) perfusion acquisitions on CT perfusion values in normal liver and liver metastases from neuroendocrine tumors. METHODS Computed tomographic perfusion in 16 patients with neuroendocrine liver metastases was analyzed using distributed-parameter modeling to yield tissue blood flow, blood volume, mean transit time, permeability, and hepatic arterial fraction for tumor and normal liver. Computed tomographic perfusion values for the reference SI of 0.5 s (SI0.5) were compared with those of SI data sets of 1 second, 2 seconds, 3 seconds, and 4 seconds using mixed-effects model analyses. RESULTS Increases in SI beyond 1 second were associated with significant and increasing departures of CT perfusion parameters from the reference values at SI0.5 (P ≤ 0.0009). Computed tomographic perfusion values deviated from the reference with increasing uncertainty with increasing SIs. Findings for normal liver were concordant. CONCLUSIONS Increasing SIs beyond 1 second yield significantly different CT perfusion parameter values compared with the reference values at SI0.5.
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Affiliation(s)
- Chaan S Ng
- From the Departments of *Diagnostic Radiology, †Biostatistics, ‡Gastrointestinal Medical Oncology, and §Imaging Physics, The University of Texas, MD Anderson Cancer Center, Houston, TX; and ∥CT Research, GE Healthcare, Waukesha, WI
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Impact of image denoising on image quality, quantitative parameters and sensitivity of ultra-low-dose volume perfusion CT imaging. Eur Radiol 2015; 26:167-74. [DOI: 10.1007/s00330-015-3853-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/20/2015] [Accepted: 05/13/2015] [Indexed: 10/23/2022]
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Othman AE, Brockmann C, Yang Z, Kim C, Afat S, Pjontek R, Nikoubashman O, Brockmann MA, Kim JH, Wiesmann M. Effects of radiation dose reduction in Volume Perfusion CT imaging of acute ischemic stroke. Eur Radiol 2015; 25:3415-22. [PMID: 25903716 DOI: 10.1007/s00330-015-3763-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 03/11/2015] [Accepted: 04/01/2015] [Indexed: 11/25/2022]
Abstract
PURPOSE To examine the influence of radiation dose reduction on image quality and sensitivity of Volume Perfusion CT (VPCT) maps regarding the detection of ischemic brain lesions. METHODS AND MATERIALS VPCT data of 20 patients with suspected ischemic stroke acquired at 80 kV and 180 mAs were included. Using realistic reduced-dose simulation, low-dose VPCT datasets with 144 mAs, 108 mAs, 72 mAs and 36 mAs (80 %, 60 %, 40 % and 20 % of the original levels) were generated, resulting in a total of 100 datasets. Perfusion maps were created and signal-to-noise-ratio (SNR) measurements were performed. Qualitative analyses were conducted by two blinded readers, who also assessed the presence/absence of ischemic lesions and scored CBV and CBF maps using a modified ASPECTS-score. RESULTS SNR of all low-dose datasets were significantly lower than those of the original datasets (p < .05). All datasets down to 72 mAs (40 %) yielded sufficient image quality and high sensitivity with excellent inter-observer-agreements, whereas 36 mAs datasets (20 %) yielded poor image quality in 15 % of the cases with lower sensitivity and inter-observer-agreements. CONCLUSION Low-dose VPCT using decreased tube currents down to 72 mAs (40 % of original radiation dose) produces sufficient perfusion maps for the detection of ischemic brain lesions. KEY POINTS • Perfusion CT is highly accurate for the detection of ischemic brain lesions • Perfusion CT results in high radiation exposure, therefore low-dose protocols are required • Reduction of tube current down to 72 mAs produces sufficient perfusion maps.
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Affiliation(s)
- Ahmed E Othman
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany.
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
| | - Carolin Brockmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - Zepa Yang
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, 433-270, South Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, 110-744, South Korea
| | - Changwon Kim
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, 433-270, South Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, 110-744, South Korea
| | - Saif Afat
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - Rastislav Pjontek
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - Omid Nikoubashman
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - Marc A Brockmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - Jong Hyo Kim
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, 433-270, South Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, 110-744, South Korea
- Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, 433-270, South Korea
| | - Martin Wiesmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
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Borst J, Marquering HA, Beenen LFM, Berkhemer OA, Dankbaar JW, Riordan AJ, Majoie CBLM. Effect of extended CT perfusion acquisition time on ischemic core and penumbra volume estimation in patients with acute ischemic stroke due to a large vessel occlusion. PLoS One 2015; 10:e0119409. [PMID: 25789631 PMCID: PMC4366202 DOI: 10.1371/journal.pone.0119409] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 01/13/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND AND PURPOSE It has been suggested that CT Perfusion acquisition times <60 seconds are too short to capture the complete in and out-wash of contrast in the tissue, resulting in incomplete time attenuation curves. Yet, these short acquisitions times are not uncommon in clinical practice. The purpose of this study was to investigate the occurrence of time attenuation curve truncation in 48 seconds CT Perfusion acquisition and to quantify its effect on ischemic core and penumbra estimation in patients with acute ischemic stroke due to a proximal intracranial arterial occlusion of the anterior circulation. MATERIALS AND METHODS We analyzed CT Perfusion data with 48 seconds and extended acquisition times, assuring full time attenuation curves, of 36 patients. Time attenuation curves were classified as complete or truncated. Ischemic core and penumbra volumes resulting from both data sets were compared by median paired differences and interquartile ranges. Controlled experiments were performed using a digital CT Perfusion phantom to investigate the effect of time attenuation curve truncation on ischemic core and penumbra estimation. RESULTS In 48 seconds acquisition data, truncation was observed in 24 (67%) cases for the time attenuation curves in the ischemic core, in 2 cases for the arterial input function and in 5 cases for the venous output function. Analysis of extended data resulted in smaller ischemic cores and larger penumbras with a median difference of 13.2 (IQR: 4.3-26.0) ml (P<0.001) and; 12.4 (IQR: 4.1-25.7) ml (P<0.001), respectively. The phantom data showed increasing ischemic core overestimation with increasing tissue time attenuation curve truncation. CONCLUSIONS Truncation is common in patients with large vessel occlusion and results in repartitioning of the area of hypoperfusion into larger ischemic core and smaller penumbra estimations. Phantom experiments confirmed that truncation results in overestimation of the ischemic core.
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Affiliation(s)
- Jordi Borst
- Department of Radiology, Academic Medical Center, Amsterdam, the Netherlands
- * E-mail:
| | - Henk A. Marquering
- Department of Radiology, Academic Medical Center, Amsterdam, the Netherlands
- Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, the Netherlands
| | - Ludo F. M. Beenen
- Department of Radiology, Academic Medical Center, Amsterdam, the Netherlands
| | - Olvert A. Berkhemer
- Department of Radiology, Academic Medical Center, Amsterdam, the Netherlands
| | | | - Alan J. Riordan
- Department of Radiology, University Medical Center Utrecht, the Netherlands
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Perfusion CT and acute stroke imaging: Foundations, applications, and literature review. J Neuroradiol 2015; 42:21-9. [DOI: 10.1016/j.neurad.2014.11.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 11/11/2014] [Indexed: 11/21/2022]
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Copen WA, Deipolyi AR, Schaefer PW, Schwamm LH, González RG, Wu O. Exposing hidden truncation-related errors in acute stroke perfusion imaging. AJNR Am J Neuroradiol 2014; 36:638-45. [PMID: 25500309 DOI: 10.3174/ajnr.a4186] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 09/22/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The durations of acute ischemic stroke patients' CT or MR perfusion scans may be too short to fully sample the passage of the injected contrast agent through the brain. We tested the potential magnitude of hidden errors related to the truncation of data by short perfusion scans. MATERIALS AND METHODS Fifty-seven patients with acute ischemic stroke underwent perfusion MR imaging within 12 hours of symptom onset, using a relatively long scan duration (110 seconds). Shorter scan durations (39.5-108.5 seconds) were simulated by progressively deleting the last-acquired images. CBV, CBF, MTT, and time to response function maximum (Tmax) were measured within DWI-identified acute infarcts, with commonly used postprocessing algorithms. All measurements except Tmax were normalized by dividing by the contralateral hemisphere values. The effects of the scan duration on these hemodynamic measurements and on the volumes of lesions with Tmax of >6 seconds were tested using regression. RESULTS Decreasing scan duration from 110 seconds to 40 seconds falsely reduced perfusion estimates by 47.6%-64.2% of normal for CBV, 1.96%-4.10% for CBF, 133%-205% for MTT, and 6.2-8.0 seconds for Tmax, depending on the postprocessing method. This truncation falsely reduced estimated Tmax lesion volume by 71.5 or 93.8 mL, depending on the deconvolution method. "Lesion reversal" (ie, change from above-normal to apparently normal, or from >6 seconds to ≤6 seconds for the time to response function maximum) with increasing truncation occurred in 37%-46% of lesions for CBV, 2%-4% for CBF, 28%-54% for MTT, and 42%-44% for Tmax, depending on the postprocessing method. CONCLUSIONS Hidden truncation-related errors in perfusion images may be large enough to alter patient management or affect outcomes of clinical trials.
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Affiliation(s)
- W A Copen
- From the Departments of Radiology (W.A.C., A.R.D., P.W.S., R.G.G., O.W.)
| | - A R Deipolyi
- From the Departments of Radiology (W.A.C., A.R.D., P.W.S., R.G.G., O.W.)
| | - P W Schaefer
- From the Departments of Radiology (W.A.C., A.R.D., P.W.S., R.G.G., O.W.)
| | - L H Schwamm
- Neurology (L.H.S.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - R G González
- From the Departments of Radiology (W.A.C., A.R.D., P.W.S., R.G.G., O.W.)
| | - O Wu
- From the Departments of Radiology (W.A.C., A.R.D., P.W.S., R.G.G., O.W.)
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Low dose CT perfusion in acute ischemic stroke. Neuroradiology 2014; 56:1055-62. [PMID: 25252738 DOI: 10.1007/s00234-014-1434-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 09/16/2014] [Indexed: 02/04/2023]
Abstract
INTRODUCTION The purpose of this investigation is to determine if CT perfusion (CTP) measurements at low doses (LD = 20 or 50 mAs) are similar to those obtained at regular doses (RD = 100 mAs), with and without the addition of adaptive statistical iterative reconstruction (ASIR). METHODS A single-center, prospective study was performed in patients with acute ischemic stroke (n = 37; 54% male; age = 74 ± 15 years). Two CTP scans were performed on each subject: one at 100 mAs (RD) and one at either 50 or 20 mAs (LD). CTP parameters were compared between the RD and LD scans in regions of ischemia, infarction, and normal tissue. Differences were determined using a within-subjects ANOVA (p < 0.05) followed by a paired t test post hoc analysis (p < 0.01). RESULTS At 50 mAs, there was no significant difference between cerebral blood flow (CBF), cerebral blood volume (CBV), or time to maximum enhancement (Tmax) values for the RD and LD scans in the ischemic, infarcted, or normal contralateral regions (p < 0.05). At 20 mAs, there were significant differences between the RD and LD scans for all parameters in the ischemic and normal tissue regions (p > 0.05). CONCLUSION CTP-derived CBF and CBV are not different at 50 mAs compared to 100 mAs, even without the addition of ASIR. Current CTP protocols can be modified to reduce the effective dose by 50 % without altering CTP measurements.
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Penumbra pattern assessment in acute stroke patients: comparison of quantitative and non-quantitative methods in whole brain CT perfusion. PLoS One 2014; 9:e105413. [PMID: 25144396 PMCID: PMC4140765 DOI: 10.1371/journal.pone.0105413] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 07/21/2014] [Indexed: 11/19/2022] Open
Abstract
Background And Purpose While penumbra assessment has become an important part of the clinical decision making for acute stroke patients, there is a lack of studies measuring the reliability and reproducibility of defined assessment techniques in the clinical setting. Our aim was to determine reliability and reproducibility of different types of three-dimensional penumbra assessment methods in stroke patients who underwent whole brain CT perfusion imaging (WB-CTP). Materials And Methods We included 29 patients with a confirmed MCA infarction who underwent initial WB-CTP with a scan coverage of 100 mm in the z-axis. Two blinded and experienced readers assessed the flow-volume-mismatch twice and in two quantitative ways: Performing a volumetric mismatch analysis using OsiriX imaging software (MMVOL) and visual estimation of mismatch (MMEST). Complementarily, the semiquantitative Alberta Stroke Programme Early CT Score for CT perfusion was used to define mismatch (MMASPECTS). A favorable penumbral pattern was defined by a mismatch of ≥30% in combination with a cerebral blood flow deficit of ≤90 ml and an MMASPECTS score of ≥1, respectively. Inter- and intrareader agreement was determined by Kappa-values and ICCs. Results Overall, MMVOL showed considerably higher inter-/intrareader agreement (ICCs: 0.751/0.843) compared to MMEST (0.292/0.749). In the subgroup of large (≥50 mL) perfusion deficits, inter- and intrareader agreement of MMVOL was excellent (ICCs: 0.961/0.942), while MMEST interreader agreement was poor (0.415) and intrareader agreement was good (0.919). With respect to penumbra classification, MMVOL showed the highest agreement (interreader agreement: 25 agreements/4 non-agreements/κ: 0.595; intrareader agreement 27/2/0.833), followed by MMEST (22/7/0.471; 23/6/0.577), and MMASPECTS (18/11/0.133; 21/8/0.340). Conclusion The evaluated approach of volumetric mismatch assessment is superior to pure visual and ASPECTS penumbra pattern assessment in WB-CTP and helps to precisely judge the extent of 3-dimensional mismatch in acute stroke patients.
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Corcuera-Solano I, McLellan AM, Doshi AH, Pawha PS, Tanenbaum LN. Whole-brain adaptive 70-kVp perfusion imaging with variable and extended sampling improves quality and consistency while reducing dose. AJNR Am J Neuroradiol 2014; 35:2045-51. [PMID: 25034777 DOI: 10.3174/ajnr.a4043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Despite common use of CTP to assess cerebral hemodynamics in the setting of ischemia, concerns over radiation exposure remain. Our aim was to evaluate the efficacy of an adaptive 70-kVp (peak) whole-brain CTP protocol with variable sampling intervals and extended duration against an established fixed-sampling, limited-period protocol at 80 kVp. MATERIALS AND METHODS A retrospective analysis of 37 patients with stroke scanned with conventional (n = 17) and variant-protocol (n = 20) whole-brain CTP was performed. We compared radiation dose, parametric map quality, and consistency of full-contrast circulation capture between a modified 70-kVp protocol, with 20 whole-brain passes at variable sampling intervals over an extended sampling period, and a conventional 80-kVp CTP examination with 24 passes at fixed-sampling intervals and a more limited scanning window. Mann-Whitney U test analysis was used to compare both protocols. RESULTS The 70-kVp CTP scan provided superior image quality at a 45% lower CT dose index volume and 13% lower dose-length product/effective dose compared with the conventional 80-kVp scan. With respect to the consistency of contrast-passage capture, 95% of the adaptive, extended protocol continued through the venous return to baseline, compared with only 47% by using the conventional limited-length protocol. Rapid sampling during the critical arterial arrival and washout period was accomplished in nearly 95% with both the variable and fixed-sampling-interval protocols. CONCLUSIONS Seventy-kilovolt (peak) CTP with variable and extended sampling produces improved image quality at lower radiation doses with greater consistency of full contrast passage capture.
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Affiliation(s)
- I Corcuera-Solano
- From the Department of Neuroradiology, Mount Sinai Medical Center, One Gustave L. Levy Place, New York, New York
| | - A M McLellan
- From the Department of Neuroradiology, Mount Sinai Medical Center, One Gustave L. Levy Place, New York, New York
| | - A H Doshi
- From the Department of Neuroradiology, Mount Sinai Medical Center, One Gustave L. Levy Place, New York, New York
| | - P S Pawha
- From the Department of Neuroradiology, Mount Sinai Medical Center, One Gustave L. Levy Place, New York, New York
| | - L N Tanenbaum
- From the Department of Neuroradiology, Mount Sinai Medical Center, One Gustave L. Levy Place, New York, New York.
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Effect of increasing the sampling interval to 2 seconds on the radiation dose and accuracy of CT perfusion of the head and neck. J Comput Assist Tomogr 2014; 38:469-73. [PMID: 24651742 DOI: 10.1097/rct.0000000000000066] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the effect of increasing the sampling interval from 1 second (1 image per second) to 2 seconds (1 image every 2 seconds) on computed tomographic (CT) perfusion (CTP) of head and neck tumors. MATERIALS AND METHODS Twenty patients underwent CTP studies of head and neck tumors with images acquired in cine mode for 50 seconds using sampling interval of 1 second. Using deconvolution-based software, analysis of CTP was done with sampling interval of 1 second and then 2 seconds. Perfusion maps representing blood flow, blood volume, mean transit time, and permeability surface area product (PS) were obtained. Quantitative tumor CTP values were compared between the 2 sampling intervals. Two blinded radiologists compared the subjective quality of CTP maps using a 3-point scale between the 2 sampling intervals. Radiation dose parameters were recorded for the 2 sampling interval rates. RESULTS No significant differences were observed between the means of the 4 perfusion parameters generated using both sampling intervals; all P >0.05. The 95% limits of agreement between the 2 sampling intervals were -65.9 to 48.1) mL/min per 100 g for blood flow, -3.6 to 3.1 mL/100 g for blood volume, -2.9 to 3.8 seconds for mean transit time, and -10.0 to 12.5 mL/min per 100 g for PS. There was no significant difference between the subjective quality scores of CTP maps obtained using the 2 sampling intervals; all P > 0.05. Radiation dose was halved when sampling interval increased from 1 to 2 seconds. CONCLUSIONS Increasing the sampling interval rate to 1 image every 2 seconds does not compromise the image quality and has no significant effect on quantitative perfusion parameters of head and neck tumors. The radiation dose is halved.
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Chu WF, Lin CJ, Chen WS, Hung SC, Chiu CF, Wu TH, Guo WY. Radiation doses of cerebral blood volume measurements using C-arm CT: A phantom study. AJNR Am J Neuroradiol 2014; 35:1073-7. [PMID: 24371024 PMCID: PMC7965136 DOI: 10.3174/ajnr.a3822] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/12/2013] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND PURPOSE Parenchymal blood volume measurement by C-arm CT facilitates in-room peritherapeutic perfusion evaluation. However, the radiation dose remains a major concern. This study aimed to compare the radiation dose of parenchymal blood volume measurement using C-arm CT with that of conventional CTP using multidetector CT. MATERIALS AND METHODS A biplane DSA equipped with C-arm CT and a Rando-Alderson phantom were used. Slab parenchymal blood volume (8-cm scanning range in a craniocaudal direction) and whole-brain parenchymal blood volume with identical scanning parameters, except for scanning ranges, were undertaken on DSA. Eighty thermoluminescent dosimeters were embedded into 22 organ sites of the phantom. We followed the guidelines of the International Commission on Radiation Protection number 103 to calculate the effective doses. For comparison, 8-cm CTP with the same phantom and thermoluminescent dosimeter distribution was performed on a multidetector CT. Two repeat dose experiments with the same scanning parameters and phantom and thermoluminescent dosimeter settings were conducted. RESULTS Brain-equivalent dose in slab parenchymal blood volume, whole-brain parenchymal blood volume, and CTP were 52.29 ± 35.31, 107.51 ± 31.20, and 163.55 ± 89.45 mSv, respectively. Variations in the measurement of an equivalent dose for the lens were highest in slab parenchymal blood volume (64.5%), followed by CTP (54.6%) and whole-brain parenchymal blood volume (29.0%). The effective doses of slab parenchymal blood volume, whole-brain parenchymal blood volume, and CTP were 0.87 ± 0.55, 3.91 ± 0.78, and 2.77 ± 1.59 mSv, respectively. CONCLUSIONS The dose measurement conducted in the current study was reliable and reproducible. The effective dose of slab parenchymal blood volume is about one-third that of CTP. With the advantages of on-site and immediate imaging availability and saving procedural time and patient transportation, slab parenchymal blood volume measurement using C-arm CT can be recommended for clinical application.
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Affiliation(s)
- W F Chu
- From the Department of Radiology (W.F.C., C.J.L., S.C.H., C.F.C., W.Y.G.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (W.F.C., C.J.L., S.C.H., C.F.C., W.Y.G.)
| | - C J Lin
- From the Department of Radiology (W.F.C., C.J.L., S.C.H., C.F.C., W.Y.G.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (W.F.C., C.J.L., S.C.H., C.F.C., W.Y.G.)
| | - W S Chen
- Department of Biomedical Imaging and Radiological Sciences (W.S.C., T.H.W.), National Yang-Ming University, Taipei, Taiwan
| | - S C Hung
- From the Department of Radiology (W.F.C., C.J.L., S.C.H., C.F.C., W.Y.G.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (W.F.C., C.J.L., S.C.H., C.F.C., W.Y.G.)
| | - C F Chiu
- From the Department of Radiology (W.F.C., C.J.L., S.C.H., C.F.C., W.Y.G.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (W.F.C., C.J.L., S.C.H., C.F.C., W.Y.G.)
| | - T H Wu
- Department of Biomedical Imaging and Radiological Sciences (W.S.C., T.H.W.), National Yang-Ming University, Taipei, Taiwan.
| | - W Y Guo
- From the Department of Radiology (W.F.C., C.J.L., S.C.H., C.F.C., W.Y.G.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (W.F.C., C.J.L., S.C.H., C.F.C., W.Y.G.)
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Thierfelder KM, Baumann AB, Sommer WH, Armbruster M, Opherk C, Janssen H, Reiser MF, Straube A, von Baumgarten L. Vertebral artery hypoplasia: frequency and effect on cerebellar blood flow characteristics. Stroke 2014; 45:1363-8. [PMID: 24699051 DOI: 10.1161/strokeaha.113.004188] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Vertebral artery hypoplasia (VAH) is supposed to be a risk factor for posterior circulation ischemia (PCI), particularly in the territory of the posterior inferior cerebellar artery (PICA). The aim of our study was to determine whether VAH impedes perfusion in the dependent PICA territory even in the absence of manifest PCI. METHODS VA diameter was retrospectively measured in 934 consecutive patients who underwent whole-brain multimodal computed tomography because of suspected stroke. VAH was defined by a diameter of ≤2 mm and an asymmetry ratio of ≤1:1.7 of both VAs. We performed blinded computed tomography perfusion reading in patients with VAH without PCI (MRI-confirmed) and in control patients (ratio 1:2) with normal VAs. Four different perfusion maps were evaluated for a relative hypoperfusion in the PICA territory. RESULTS VAH was found in 146 of 934 patients (15.6%). It was more frequent on the right side (66.1%). Of 146 patients, 59 without PCI qualified for computed tomography perfusion analysis. Depending on the perfusion map, ≤42.4% (25/59) of patients with VAH, but only 7.6% (9/118) without VAH, showed an ipsilateral PICA hypoperfusion (P<0.001). Sensitivities in patients with VAH were as follows: time to drain 42.4% (25/59)>mean transit time 39.0% (23/59)>cerebral blood flow 25.4% (15/59). Cerebral blood volume was never affected. CONCLUSIONS VAH is a frequent vascular variant that can lead to a relative regional hypoperfusion in the PICA territory. Additional research should clarify the pathophysiological role of VAH in PCI.
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Affiliation(s)
- Kolja M Thierfelder
- From the Department of Clinical Radiology (K.M.T., A.B.B., W.H.S., M.A., M.F.R.), Department of Neurology (C.O., A.S., L.v.B.), Institute for Stroke and Dementia Research (C.O.), and Department of Neuroradiology (H.J.), Ludwig-Maximilians-University of Munich Hospitals, Munich, Germany
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Radiation dose reduction in cerebral CT perfusion imaging using iterative reconstruction. Eur Radiol 2013; 24:484-93. [DOI: 10.1007/s00330-013-3042-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 09/02/2013] [Accepted: 09/25/2013] [Indexed: 10/26/2022]
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Lin CJ, Wu TH, Lin CH, Hung SC, Chiu CF, Liu MJ, Teng MMH, Chang FC, Guo WY, Chang CY. Can iterative reconstruction improve imaging quality for lower radiation CT perfusion? Initial experience. AJNR Am J Neuroradiol 2013; 34:1516-21. [PMID: 23578678 DOI: 10.3174/ajnr.a3436] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Initial results using IR for CT of the head showed satisfactory subjective and objective imaging quality with a 20-40% radiation dose reduction. The aim of our study was to compare the influence of IR and FBP algorithms on perfusion parameters at standard and lowered doses of CTP. MATERIALS AND METHODS Forty patients with unilateral carotid stenosis post-carotid stent placement referred for follow-up CTP were divided into 2 groups (tube currents were 100 mAs in group A and 80 mAs in group B). Datasets were reconstructed with IR and FBP algorithms; and SNRs of gray matter, white matter, and arterial and venous ROIs were compared. CBF, CBV, and MTT means and SNRs were evaluated by using linear regression, and qualitative imaging scores were compared across the 2 algorithms. RESULTS The mean effective radiation dose of group B (2.06 mSv) was approximately 20% lower than that of group A (2.56 mSv). SNRs for ROIs in the dynamic contrast-enhanced images were significantly higher than those for the FBP images. Correlations of the SNRs for CBF, CBV, and MTT across the 2 algorithms were moderate (R² = 0.46, 0.23, and 0.44, respectively). ROIs in gray matter rather than the IR algorithm predicted increasing SNRs in all CBF, CBV, and MTT maps. Two cases of significant restenosis were confirmed in both algorithms. CBV, CBF, and MTT imaging scores did not differ significantly across algorithms or groups. CONCLUSIONS Lower dose CTP (20% below normal dose) without IR can effectively identify oligemic tissue in poststenting follow-up. IR does not alter the absolute values or increase the SNRs of perfusion parameters. Other methods should be attempted to improve SNRs in settings with low tube currents.
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Affiliation(s)
- C J Lin
- Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan
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Whole-brain CT perfusion: reliability and reproducibility of volumetric perfusion deficit assessment in patients with acute ischemic stroke. Neuroradiology 2013; 55:827-35. [DOI: 10.1007/s00234-013-1179-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Accepted: 03/21/2013] [Indexed: 10/27/2022]
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Flohr T. Multi-Detector Row CT–Recent Developments, Radiation Dose and Dose Reduction Technologies. RADIATION DOSE FROM MULTIDETECTOR CT 2012. [DOI: 10.1007/174_2011_499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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