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For: van der Werf NR, Booij R, Greuter MJW, Bos D, van der Lugt A, Budde RPJ, van Straten M. Reproducibility of coronary artery calcium quantification on dual-source CT and dual-source photon-counting CT: a dynamic phantom study. Int J Cardiovasc Imaging 2022;38:1613-1619. [PMID: 35113282 PMCID: PMC11142942 DOI: 10.1007/s10554-022-02540-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/24/2022] [Indexed: 12/19/2022]

For:	van der Werf NR, Booij R, Greuter MJW, Bos D, van der Lugt A, Budde RPJ, van Straten M. Reproducibility of coronary artery calcium quantification on dual-source CT and dual-source photon-counting CT: a dynamic phantom study. Int J Cardiovasc Imaging 2022;38:1613-1619. [PMID: 35113282 PMCID: PMC11142942 DOI: 10.1007/s10554-022-02540-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/24/2022] [Indexed: 12/19/2022]

Number

Cited by Other Article(s)

Meloni A, Maffei E, Positano V, Clemente A, De Gori C, Berti S, La Grutta L, Saba L, Bossone E, Mantini C, Cavaliere C, Punzo B, Celi S, Cademartiri F. Technical principles, benefits, challenges, and applications of photon counting computed tomography in coronary imaging: a narrative review. Cardiovasc Diagn Ther 2024;14:698-724. [PMID: 39263472 PMCID: PMC11384460 DOI: 10.21037/cdt-24-52] [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: 01/29/2024] [Accepted: 06/27/2024] [Indexed: 09/13/2024]

Fink N, Emrich T, Schoepf UJ, Zsarnoczay E, O’Doherty J, Halfmann MC, Griffith JP, Pinos D, Suranyi P, Baruah D, Kabakus IM, Ricke J, Varga-Szemes A. Improved Detection of Small and Low-Density Plaques in Virtual Noncontrast Imaging-based Calcium Scoring at Photon-Counting Detector CT. Radiol Cardiothorac Imaging 2024;6:e230328. [PMID: 39023373 PMCID: PMC11369658 DOI: 10.1148/ryct.230328] [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: 06/09/2023] [Revised: 03/26/2024] [Accepted: 05/30/2024] [Indexed: 07/20/2024]

Abstract

Purpose To investigate the impact of plaque size and density on virtual noncontrast (VNC)-based coronary artery calcium scoring (CACS) using photon-counting detector CT and to provide safety net reconstructions for improved detection of subtle plaques in patients whose VNC-based CACS would otherwise be erroneously zero when compared with true noncontrast (TNC)-based CACS. Materials and Methods In this prospective study, CACS was evaluated in a phantom containing calcifications with different diameters (5, 3, and 1 mm) and densities (800, 400, and 200 mg/cm3) and in participants who underwent TNC and contrast-enhanced cardiac photon-counting detector CT (July 2021-March 2022). VNC images were reconstructed at different virtual monoenergetic imaging (55-80 keV) and quantum iterative reconstruction (QIR) levels (QIR,1-4). TNC scans at 70 keV with QIR off served as the reference standard. In vitro CACS was analyzed using standard settings (3.0-mm sections, kernel Qr36, 130-HU threshold). Calcification detectability and CACS of small and low-density plaques were also evaluated using 1.0-mm sections, kernel Qr44, and 120- or 110-HU thresholds. Safety net reconstructions were defined based on background Agatston scores and evaluated in vivo in TNC plaques initially nondetectable using standard VNC reconstructions. Results The in vivo cohort included 63 participants (57.8 years ± 15.5 [SD]; 37 [59%] male, 26 [41%] female). Correlation and agreement between standard CACSVNC and CACSTNC were higher in large- and medium-sized and high- and medium-density than in low-density plaques (in vitro: intraclass correlation coefficient [ICC] ≥ 0.90; r > 0.9 vs ICC = 0.20-0.48; r = 0.5-0.6). Small plaques were not detectable using standard VNC reconstructions. Calcification detectability was highest using 1.0-mm sections, kernel Qr44, 120- and 110-HU thresholds, and QIR level of 2 or less VNC reconstructions. Compared with standard VNC, using safety net reconstructions (55 keV, QIR 2, 110-HU threshold) for in vivo subtle plaque detection led to higher detection (increased by 89% [50 of 56]) and improved correlation and agreement of CACSVNC with CACSTNC (in vivo: ICC = 0.51-0.61; r = 0.6). Conclusion Compared with TNC-based calcium scoring, VNC-based calcium scoring was limited for small and low-density plaques but improved using safety net reconstructions, which may be particularly useful in patients with low calcium scores who would otherwise be treated based on potentially false-negative results. Keywords: Coronary Artery Calcium CT, Photon-Counting Detector CT, Virtual Noncontrast, Plaque Size, Plaque Density Supplemental material is available for this article. © RSNA, 2024.

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Affiliation(s)

Nicola Fink From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Tilman Emrich From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
U. Joseph Schoepf From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Emese Zsarnoczay From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Jim O’Doherty From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Moritz C. Halfmann From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Joseph P. Griffith From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Daniel Pinos From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Pal Suranyi From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Dhiraj Baruah From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Ismail M. Kabakus From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Jens Ricke From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)
Akos Varga-Szemes From the Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Dr, MUSC 226, Charleston, SC 29425-2260 (N.F., T.E., U.J.S., E.Z., J.O., J.P.G., D.P., P.S., D.B., I.M.K., A.V.S.); Department of Radiology, University Hospital, LMU Munich, Munich, Germany (N.F., J.R.); Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg-University, Mainz, Germany (T.E., M.C.H.); German Centre for Cardiovascular Research, Mainz, Germany (T.E.); Medical Imaging Center, Semmelweis University, Budapest, Hungary (E.Z.); and Siemens Medical Solutions, Malvern, Pa (J.O.)

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Risch F, Schwarz F, Kroencke T, Decker JA. Heart rate sensitivity of virtual non-contrast calcium scores derived from photon counting detector CT data: a phantom study. LA RADIOLOGIA MEDICA 2024;129:401-410. [PMID: 38319495 PMCID: PMC10943147 DOI: 10.1007/s11547-024-01773-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 01/03/2024] [Indexed: 02/07/2024]

Abstract

PURPOSE

To assess the reliability of virtual non-contrast (VNC) derived coronary artery calcium quantities in relation to heart rate and the VNC algorithm used compared to reference true non-contrast (TNC), considering several clinically established acquisition modes.

MATERIAL AND METHODS

An ad hoc built coronary phantom containing four calcified lesions and an iodinated lumen was scanned using three cardiac acquisition modes three times within an anthropomorphic cardiac motion phantom simulating different heart rates (0, 60, 80, 100 bpm) and reconstructed with a conventional (VNCconv) and a calcium-sensitive (VNCpc) VNC algorithm. TNC reference was scanned at 0 bpm with non-iodinated lumen. Calcium scores were assessed in terms of number of lesions detected, Agatston and volume scores and global noise was measured. Paired t-test and Wilcoxon test were performed to test measurements for significant difference.

RESULTS

For both VNC algorithms used, calcium levels or noise were not significantly affected by heart rate. Measurements on VNCpc reconstructions best reproduced TNC results, but with increased variability (Agatston scores at 0 bpm for TNC, VNCconv, and VNCpc were 47.1 ± 1.1, 6.7 ± 2.8 (p < 0.001), and 45.3 ± 7.6 (p > 0.05), respectively). VNC reconstructions showed lower noise levels compared to TNC, especially for VNCpc (noiseheart on TNC, VNCconv and VNCpc at 0 bpm was 5.0 ± 0.4, 4.5 ± 0.2, 4.2 ± 0.2).

CONCLUSION

No significant heart rate dependence of VNC-based calcium scores was observed in an intra-reconstruction comparison. VNCpc reproduces TNC scores better than VNCconv without significant differences and decreased noise, however, with an increasing average deviation with rising heart rates. VNC-based CACS should be used with caution as the measures show higher variability compared to reference TNC and therefore hold the potential of incorrect risk categorization.

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Sartoretti T, Mergen V, Dzaferi A, Allmendinger T, Manka R, Alkadhi H, Eberhard M. Effect of temporal resolution on calcium scoring: insights from photon-counting detector CT. THE INTERNATIONAL JOURNAL OF CARDIOVASCULAR IMAGING 2024:10.1007/s10554-024-03070-6. [PMID: 38389028 DOI: 10.1007/s10554-024-03070-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 02/13/2024] [Indexed: 02/24/2024]

Abstract

To intra-individually investigate the variation of coronary artery calcium (CAC), aortic valve calcium (AVC), and mitral annular calcium (MAC) scores and the presence of blur artifacts as a function of temporal resolution in patients undergoing non-contrast cardiac CT on a dual-source photon counting detector (PCD) CT. This retrospective, IRB-approved study included 70 patients (30 women, 40 men, mean age 78 ± 9 years) who underwent ECG-gated cardiac non-contrast CT with PCD-CT (gantry rotation time 0.25 s) prior to transcatheter aortic valve replacement. Each scan was reconstructed at a temporal resolution of 66 ms using the dual-source information and at 125 ms using the single-source information. Average heart rate and heart rate variability were calculated from the recorded ECG. CAC, AVC, and MAC were quantified according to the Agatston method on images with both temporal resolutions. Two readers assessed blur artifacts using a 4-point visual grading scale. The influence of average heart rate and heart rate variability on calcium quantification and blur artifacts of the respective structures were analyzed by linear regression analysis. Mean heart rate and heart rate variability during data acquisition were 76 ± 17 beats per minute (bpm) and 4 ± 6 bpm, respectively. CAC scores were smaller on 66 ms (median, 511; interquartile range, 220-978) than on 125 ms reconstructions (538; 203-1050, p < 0.001). Median AVC scores [2809 (2009-3952) versus 3177 (2158-4273)] and median MAC scores [226 (0-1284) versus 251 (0-1574)] were also significantly smaller on 66ms than on 125ms reconstructions (p < 0.001). Reclassification of CAC and AVC risk categories occurred in 4% and 11% of cases, respectively, whereby the risk category was always overestimated on 125ms reconstructions. Image blur artifacts were significantly less on 66ms as opposed to 125 ms reconstructions (p < 0.001). Intra-individual analyses indicate that temporal resolution significantly impacts on calcium scoring with cardiac CT, with CAC, MAC, and AVC being overestimated at lower temporal resolution because of increased motion artifacts eventually leading to an overestimation of patient risk.

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Fink N, Zsarnoczay E, Schoepf UJ, O'Doherty J, Halfmann MC, Allmendinger T, Hagenauer J, Griffith JP, Vecsey-Nagy M, Pinos D, Ebersberger U, Ricke J, Varga-Szemes A, Emrich T. Impact of Cardiac Motion on coronary artery calcium scoring using a virtual non-iodine algorithm on photon-counting detector CT: a dynamic phantom study. THE INTERNATIONAL JOURNAL OF CARDIOVASCULAR IMAGING 2023;39:2083-2092. [PMID: 37452987 DOI: 10.1007/s10554-023-02912-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/27/2023] [Indexed: 07/18/2023]

Affiliation(s)

Nicola Fink Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Dr, Charleston, SC, 29425, USA Department of Radiology, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
Emese Zsarnoczay Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Dr, Charleston, SC, 29425, USA Medical Imaging Center, Semmelweis University, Korányi Sándor utca 2, Budapest, 1083, Hungary
U Joseph Schoepf Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Dr, Charleston, SC, 29425, USA.
Jim O'Doherty Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Dr, Charleston, SC, 29425, USA Siemens Medical Solutions, Malvern, PA, 19355, USA
Moritz C Halfmann Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg- University, Langenbeckstr. 1, Mainz, 55131, Germany
Thomas Allmendinger Siemens Healthcare GmbH, Siemensstr. 1, Forchheim, 91301, Germany
Junia Hagenauer Siemens Healthcare GmbH, Siemensstr. 1, Forchheim, 91301, Germany Faculty of Medicine, Friedrich Alexander University of Erlangen-Nuremberg, Krankenhausstr. 12, Erlangen, 91054, Germany
Joseph P Griffith Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Dr, Charleston, SC, 29425, USA
Milán Vecsey-Nagy Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Dr, Charleston, SC, 29425, USA MTA-SE Cardiovascular Imaging Research Group, Heart and Vascular Center, Semmelweis University, Varosmajor utca 68, Budapest, 1122, Hungary
Daniel Pinos Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Dr, Charleston, SC, 29425, USA
Ullrich Ebersberger Department of Cardiology, Munich University Clinic, Ludwig-Maximilians-University, Munich, 80636, Germany
Jens Ricke Department of Radiology, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
Akos Varga-Szemes Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Dr, Charleston, SC, 29425, USA
Tilman Emrich Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Dr, Charleston, SC, 29425, USA Department of Diagnostic and Interventional Radiology, University Medical Center of Johannes Gutenberg- University, Langenbeckstr. 1, Mainz, 55131, Germany German Centre for Cardiovascular Research, Mainz, 55131, Germany

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Marsh JF, VanMeter PD, Rajendran K, Leng S, McCollough CH. Ex vivo coronary calcium volume quantification using a high-spatial-resolution clinical photon-counting-detector computed tomography. J Med Imaging (Bellingham) 2023;10:043501. [PMID: 37408984 PMCID: PMC10319293 DOI: 10.1117/1.jmi.10.4.043501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 04/17/2023] [Accepted: 06/20/2023] [Indexed: 07/07/2023] Open

Abstract

Purpose

Coronary artery calcification (CAC) is an important indicator of coronary disease. Accurate volume quantification of CAC is challenging using computed tomography (CT) due to calcium blooming, which is a consequence of limited spatial resolution. Ex vivo coronary specimens were scanned on an ultra-high-resolution (UHR) clinical photon-counting detector (PCD) CT scanner, and the accuracy of CAC volume estimation was compared with a state-of-the-art conventional energy-integrating detector (EID) CT, a previous-generation investigational PCD-CT, and micro-CT.

Approach

CAC specimens (n = 13 ) were scanned on EID-CT and PCD-CT using matched parameters (120 kV, 9.3 mGy CTDI vol ). EID-CT images were reconstructed using our institutional routine clinical protocol for CAC quantification. UHR PCD-CT data were reconstructed using a sharper kernel. An image-based denoising algorithm was applied to the PCD-CT images to achieve similar noise levels as EID-CT. Micro-CT images served as the volume reference standard. Calcification images were segmented, and their volume estimates were compared. The CT data were further compared with previous work using an investigational PCD-CT.

Results

Compared with micro-CT, CT volume estimates had a mean absolute percent error of 24.1 % ± 25.6 % for clinical PCD-CT, 60.1 % ± 48.2 % for EID-CT, and 51.1 % ± 41.7 % for previous-generation PCD-CT. Clinical PCD-CT absolute percent error was significantly (p < 0.01 ) lower than both EID-CT and previous generation PCD-CT. The mean calcification CT number and contrast-to-noise ratio were both significantly (p < 0.01 ) higher in clinical PCD-CT relative to EID-CT.

Conclusions

UHR clinical PCD-CT showed reduced calcium blooming artifacts and further enabled improved accuracy of CAC quantification beyond that of conventional EID-CT and previous generation PCD-CT systems.

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Flohr T, Schmidt B. Technical Basics and Clinical Benefits of Photon-Counting CT. Invest Radiol 2023;58:441-450. [PMID: 37185302 PMCID: PMC10259209 DOI: 10.1097/rli.0000000000000980] [Citation(s) in RCA: 39] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 03/05/2023] [Indexed: 05/17/2023]

Mergen V, Ghouse S, Sartoretti T, Manka R, Euler A, Kasel AM, Alkadhi H, Eberhard M. Cardiac Virtual Noncontrast Images for Calcium Quantification with Photon-counting Detector CT. Radiol Cardiothorac Imaging 2023;5:e220307. [PMID: 37404795 PMCID: PMC10316300 DOI: 10.1148/ryct.220307] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/29/2023] [Accepted: 05/08/2023] [Indexed: 07/06/2023]

Abstract

Purpose

To assess the accuracy of aortic valve calcium (AVC), mitral annular calcium (MAC), and coronary artery calcium (CAC) quantification and risk stratification using virtual noncontrast (VNC) images from late enhancement photon-counting detector CT as compared with true noncontrast images.

Materials and Methods

This retrospective, institutional review board-approved study evaluated patients undergoing photon-counting detector CT between January and September 2022. VNC images were reconstructed from late enhancement cardiac scans at 60, 70, 80, and 90 keV using quantum iterative reconstruction (QIR) strengths of 2-4. AVC, MAC, and CAC were quantified on VNC images and compared with quantification of AVC, MAC, and CAC on true noncontrast images using Bland-Altman analyses, regression models, intraclass correlation coefficients (ICC), and Wilcoxon tests. Agreement between severe aortic stenosis likelihood categories and CAC risk categories determined from VNC and true noncontrast images was assessed by weighted κ analysis.

Results

Ninety patients were included (mean age, 80 years ± 8 [SD]; 49 male patients). Scores were similar on true noncontrast images and VNC images at 80 keV for AVC and MAC, regardless of QIR strengths, and VNC images at 70 keV with QIR 4 for CAC (all P > .05). The best results were achieved using VNC images at 80 keV with QIR 4 for AVC (mean difference, 3; ICC = 0.992; r = 0.98) and MAC (mean difference, 6; ICC = 0.998; r = 0.99), and VNC images at 70 keV with QIR 4 for CAC (mean difference, 28; ICC = 0.996; r = 0.99). Agreement between calcification categories was excellent on VNC images at 80 keV for AVC (κ = 0.974) and on VNC images at 70 keV for CAC (κ = 0.967).

Conclusion

VNC images from cardiac photon-counting detector CT enables patient risk stratification and accurate quantification of AVC, MAC, and CAC.Keywords: Coronary Arteries, Aortic Valve, Mitral Valve, Aortic Stenosis, Calcifications, Photon-counting Detector CT Supplemental material is available for this article © RSNA, 2023.

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Sonnow L, Salimova N, Behrendt L, Wacker FK, Örgel M, Plagge J, Weidemann F. Photon-counting CT of elbow joint fractures: image quality in a simulated post-trauma setting with off-center positioning. Eur Radiol Exp 2023;7:15. [PMID: 36967394 PMCID: PMC10040392 DOI: 10.1186/s41747-023-00329-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/30/2023] [Indexed: 03/28/2023] Open

Abstract

BACKGROUND

Photon-counting detector computed tomography (PCD-CT) has the potential to provide superior image quality compared to energy-integrating detector computed tomography (EID-CT). We compared the two systems for elbow imaging in off-center arm positioning, 90° flexion, and cast fixation in a simulated post-trauma setting.

METHODS

The institutional review board approved the study protocol. In a cadaver study, an olecranon fracture was artificially created in ten whole arm specimens. Two different scanning positions were evaluated: (a) arm overhead; and (b) arm on top of the abdomen of a whole-body phantom. The ultra-high resolution mode with three dose protocols and two reconstruction kernels was applied. Two blinded radiologists independently evaluated fracture and trabecular bone delineation. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and cortical sharpness measurements were performed. Cohen κ correlations, Mann-Whitney U and Wilcoxon signed rank tests were used. A p value lower than 0.05 was considered statistically significant.

RESULTS

Dose-equivalent PCD-CT scans were rated better for fracture and trabecular bone evaluation (p < 0.001). SNR, CNR, and cortical sharpness were higher for all diagnostic (Br76) PCD-CT images (p < 0.001). The arm position had less effect on image quality in the PCD-CT compared to the EID-CT. The use of a sharp bone kernel (Br89) improved image quality ratings for PCD-CT. In the low-dose scan mode, PCD-CT resulted in more diagnostic scans (75%) compared to EID-CT (19%).

CONCLUSIONS

PCD-CT provided superior objective and subjective image quality for fracture and trabecular bone structures delineation of the elbow compared to EID-CT in a typical post-trauma setting.

KEY POINTS

• Photon-counting detector computed tomography (PCD-CT) preserved high image quality in elbow imaging with off-center positions. • PCD-CT was advantageous for bone evaluation in trauma elbows. • PCD-CT ultra-high-resolution mode and very sharp reconstruction kernels facilitated higher image quality.

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Photon Counting Detector CT-Based Virtual Noniodine Reconstruction Algorithm for In Vitro and In Vivo Coronary Artery Calcium Scoring: Impact of Virtual Monoenergetic and Quantum Iterative Reconstructions. Invest Radiol 2023:00004424-990000000-00091. [PMID: 36822677 DOI: 10.1097/rli.0000000000000959] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]

Abstract

OBJECTIVES

The aim of this study was to evaluate the impact of virtual monoenergetic imaging (VMI) and quantum iterative reconstruction (QIR) on the accuracy of coronary artery calcium scoring (CACS) using a virtual noniodine (VNI) reconstruction algorithm on a first-generation, clinical, photon counting detector computed tomography system.

MATERIALS AND METHODS

Coronary artery calcium scoring was evaluated in an anthropomorphic chest phantom simulating 3 different patient sizes by using 2 extension rings (small: 300 × 200 mm, medium: 350 × 250 mm, large: 400 × 300 mm) and in patients (n = 61; final analyses only in patients with coronary calcifications [n = 34; 65.4 ± 10.0 years; 73.5% male]), who underwent nonenhanced and contrast-enhanced, electrocardiogram-gated, cardiac computed tomography on a photon counting detector system. Phantom and patient data were reconstructed using a VNI reconstruction algorithm at different VMI (55-80 keV) and QIR (strength 1-4) levels (CACSVNI). True noncontrast (TNC) scans at 70 keV and QIR "off" were used as reference for phantom and patient studies (CACSTNC).

RESULTS

In vitro and in vivo CACSVNI showed strong correlation (r > 0.9, P < 0.001 for all) and excellent agreement (intraclass correlation coefficient > 0.9 for all) with CACSTNC at all investigated VMI and QIR levels. Phantom and patient CACSVNI significantly increased with decreasing keV levels (in vitro: from 475.2 ± 26.3 at 80 keV up to 652.5 ± 42.2 at 55 keV; in vivo: from 142.5 [7.4/737.7] at 80 keV up to 248.1 [31.2/1144] at 55 keV; P < 0.001 for all), resulting in an overestimation of CACSVNI at 55 keV compared with CACSTNC at 70 keV in some cases (in vitro: 625.8 ± 24.4; in vivo: 225.4 [35.1/959.7]). In vitro CACS increased with rising QIR at low keV. In vivo scores were significantly higher at QIR 1 compared with QIR 4 only at 60 and 80 keV (60 keV: 220.3 [29.6-1060] vs 219.5 [23.7/1048]; 80 keV: 152.0 [12.0/735.6] vs 142.5 [7.4/737.7]; P < 0.001). CACSVNI was closest to CACSTNC at 60 keV, QIR 2 (+0.1%) in the small; 55 keV, QIR 1 (±0%) in the medium; 55 keV, QIR 4 (-0.1%) in the large phantom; and at 60 keV, QIR 1 (-2.3%) in patients.

CONCLUSIONS

Virtual monoenergetic imaging reconstructions have a significant impact on CACSVNI. The effects of different QIR levels are less consistent and seem to depend on several individual conditions, which should be further investigated.

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An introduction to photon-counting detector CT (PCD CT) for radiologists. Jpn J Radiol 2023;41:266-282. [PMID: 36255601 PMCID: PMC9974724 DOI: 10.1007/s11604-022-01350-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 10/01/2022] [Indexed: 10/24/2022]

Cademartiri F, Maurovich-Horvat P. Current role of coronary calcium in younger population and future prospects with photon counting technology. Eur Heart J Cardiovasc Imaging 2022;24:25-26. [PMID: 36394362 PMCID: PMC9762930 DOI: 10.1093/ehjci/jeac214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open