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Horst KK, Yu L, McCollough CH, Esquivel A, Thorne JE, Rajiah PS, Baffour F, Hull NC, Weber NM, Thacker PG, Thomas KB, Binkovitz LA, Guerin JB, Fletcher JG. Potential benefits of photon counting detector computed tomography in pediatric imaging. Br J Radiol 2023; 96:20230189. [PMID: 37750939 PMCID: PMC10646626 DOI: 10.1259/bjr.20230189] [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: 02/21/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/27/2023] Open
Abstract
Photon counting detector (PCD) CT represents the newest advance in CT technology, with improved radiation dose efficiency, increased spatial resolution, inherent spectral imaging capabilities, and the ability to eliminate electronic noise. Its design fundamentally differs from conventional energy integrating detector CT because photons are directly converted to electrical signal in a single step. Rather than converting X-rays to visible light and having an output signal that is a summation of energies, PCD directly counts each photon and records its individual energy information. The current commercially available PCD-CT utilizes a dual-source CT geometry, which allows 66 ms cardiac temporal resolution and high-pitch (up to 3.2) scanning. This can greatly benefit pediatric patients by facilitating high quality fast scanning to allow sedation-free imaging. The energy-resolving nature of the utilized PCDs allows "always-on" dual-energy imaging capabilities, such as the creation of virtual monoenergetic, virtual non-contrast, virtual non-calcium, and other material-specific images. These features may be combined with high-resolution imaging, made possible by the decreased size of individual detector elements and the absence of interelement septa. This work reviews the foundational concepts associated with PCD-CT and presents examples to highlight the benefits of PCD-CT in the pediatric population.
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Affiliation(s)
- Kelly K. Horst
- Pediatric Radiology Division, Department of Radiology, Mayo Clinic, Rochester, United States
| | - Lifeng Yu
- Department of Radiology, Mayo Clinic, Rochester, United States
| | | | - Andrea Esquivel
- Department of Radiology, Mayo Clinic, Rochester, United States
| | | | | | - Francis Baffour
- Department of Radiology, Mayo Clinic, Rochester, United States
| | - Nathan C. Hull
- Pediatric Radiology Division, Department of Radiology, Mayo Clinic, Rochester, United States
| | | | - Paul G. Thacker
- Pediatric Radiology Division, Department of Radiology, Mayo Clinic, Rochester, United States
| | - Kristen B. Thomas
- Pediatric Radiology Division, Department of Radiology, Mayo Clinic, Rochester, United States
| | - Larry A. Binkovitz
- Pediatric Radiology Division, Department of Radiology, Mayo Clinic, Rochester, United States
| | - Julie B. Guerin
- Department of Radiology, Mayo Clinic, Rochester, United States
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Ultrahigh-Resolution Photon-Counting Detector CT of the Lungs: Association of Reconstruction Kernel and Slice Thickness With Image Quality. AJR Am J Roentgenol 2023; 220:672-680. [PMID: 36475813 DOI: 10.2214/ajr.22.28515] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND. Prior work has shown improved image quality for photon-counting detector (PCD) CT of the lungs compared with energy-integrating detector CT. A paucity of the literature has compared PCD CT of the lungs using different reconstruction parameters. OBJECTIVE. The purpose of this study is to the compare the image quality of ultra-high-resolution (UHR) PCD CT image sets of the lungs that were reconstructed using different kernels and slice thicknesses. METHODS. This retrospective study included 29 patients (17 women and 12 men; median age, 56 years) who underwent noncontrast chest CT from February 15, 2022, to March 15, 2022, by use of a commercially available PCD CT scanner. All acquisitions used UHR mode (1024 × 1024 matrix). Nine image sets were reconstructed for all combinations of three sharp kernels (BI56, BI60, and BI64) and three slice thicknesses (0.2, 0.4, and 1.0 mm). Three radiologists independently reviewed reconstructions for measures of visualization of pulmonary anatomic structures and pathologies; reader assessments were pooled. Reconstructions were compared with the clinical reference reconstruction (obtained using the BI64 kernel and a 1.0-mm slice thickness [BI641.0-mm]). RESULTS. The median difference in the number of bronchial divisions identified versus the clinical reference reconstruction was higher for reconstructions with BI640.4-mm (0.5), BI600.4-mm (0.3), BI640.2-mm (0.5), and BI600.2-mm (0.2) (all p < .05). The median bronchial wall sharpness versus the clinical reference reconstruction was higher for reconstructions with BI640.4-mm (0.3) and BI640.2-mm (0.3) and was lower for BI561.0-mm (-0.7) and BI560.4-mm (-0.3) (all p < .05). Median pulmonary fissure sharpness versus the clinical reference reconstruction was higher for reconstructions with BI640.4-mm (0.3), BI600.4-mm (0.3), BI560.4-mm (0.5), BI640.2-mm (0.5), BI600.2-mm (0.5), and BI560.2-mm (0.3) (all p < .05). Median pulmonary vessel sharpness versus the clinical reference reconstruction was lower for reconstructions with BI561.0-mm (-0.3), BI60 0.4-mm (-0.3), BI560.4-mm (-0.7), BI640.2-mm (-0.7), BI600.2-mm (-0.7), and BI560.2-mm (-0.7). Median lung nodule conspicuity versus the clinical reference reconstruction was lower for reconstructions with BI561.0-mm (-0.3) and BI560.4-mm (-0.3) (both p < .05). Median conspicuity of all other pathologies versus the clinical reference reconstruction was lower for reconstructions with BI561.0 mm (-0.3), BI560.4-mm (-0.3), BI640.2-mm (-0.3), BI600.2-mm (-0.3), and BI560.2-mm (-0.3). Other comparisons among reconstructions were not significant (all p > .05). CONCLUSION. Only the reconstruction using BI640.4-mm yielded improved bronchial division identification and bronchial wall and pulmonary fissure sharpness without a loss in pulmonary vessel sharpness or conspicuity of nodules or other pathologies. CLINICAL IMPACT. The findings of this study may guide protocol optimization for UHR PCD CT of the lungs.
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Spectral Photon-Counting CT Technology in Chest Imaging. J Clin Med 2021; 10:jcm10245757. [PMID: 34945053 PMCID: PMC8704215 DOI: 10.3390/jcm10245757] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 12/17/2022] Open
Abstract
The X-ray imaging field is currently undergoing a period of rapid technological innovation in diagnostic imaging equipment. An important recent development is the advent of new X-ray detectors, i.e., photon-counting detectors (PCD), which have been introduced in recent clinical prototype systems, called PCD computed tomography (PCD-CT) or photon-counting CT (PCCT) or spectral photon-counting CT (SPCCT) systems. PCD allows a pixel up to 200 microns pixels at iso-center, which is much smaller than that can be obtained with conventional energy integrating detectors (EID). PCDs have also a higher dose efficiency than EID mainly because of electronic noise suppression. In addition, the energy-resolving capabilities of these detectors allow generating spectral basis imaging, such as the mono-energetic images or the water/iodine material images as well as the K-edge imaging of a contrast agent based on atoms of high atomic number. In recent years, studies have therefore been conducted to determine the potential of PCD-CT as an alternative to conventional CT for chest imaging.
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Kopp FK, Daerr H, Si-Mohamed S, Sauter AP, Ehn S, Fingerle AA, Brendel B, Pfeiffer F, Roessl E, Rummeny EJ, Pfeiffer D, Proksa R, Douek P, Noël PB. Evaluation of a preclinical photon-counting CT prototype for pulmonary imaging. Sci Rep 2018; 8:17386. [PMID: 30478300 PMCID: PMC6255779 DOI: 10.1038/s41598-018-35888-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/09/2018] [Indexed: 12/19/2022] Open
Abstract
The purpose of this study was to investigate a preclinical spectral photon-counting CT (SPCCT) prototype compared to conventional CT for pulmonary imaging. A custom-made lung phantom, including nodules of different sizes and shapes, was scanned with a preclinical SPCCT and a conventional CT in standard and high-resolution (HR-CT) mode. Volume estimation was evaluated by linear regression. Shape similarity was evaluated with the Dice similarity coefficient. Spatial resolution was investigated via MTF for each imaging system. In-vivo rabbit lung images from the SPCCT system were subjectively reviewed. Evaluating the volume estimation, linear regression showed best results for the SPCCT compared to CT and HR-CT with a root mean squared error of 21.3 mm3, 28.5 mm3 and 26.4 mm3 for SPCCT, CT and HR-CT, respectively. The Dice similarity coefficient was superior for SPCCT throughout nodule shapes and all nodule sizes (mean, SPCCT: 0.90; CT: 0.85; HR-CT: 0.85). 10% MTF improved from 10.1 LP/cm for HR-CT to 21.7 LP/cm for SPCCT. Visual investigation of small pulmonary structures was superior for SPCCT in the animal study. In conclusion, the SPCCT prototype has the potential to improve the assessment of lung structures due to higher resolution compared to conventional CT.
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Affiliation(s)
- Felix K Kopp
- Department of diagnostic and interventional Radiology, Technische Universität München, Munich, Germany.
| | - Heiner Daerr
- Philips GmbH Innovative Technologies, Research Laboratories, Hamburg, Germany
| | - Salim Si-Mohamed
- Department of Interventional Radiology and Cardio-vascular and Thoracic Diagnostic Imaging, Louis Pradel University Hospital, Bron, France.,CREATIS, CNRS UMR 5220, INSERM U1206, INSA-Lyon, France
| | - Andreas P Sauter
- Department of diagnostic and interventional Radiology, Technische Universität München, Munich, Germany
| | - Sebastian Ehn
- Chair of Biomedical Physics, Department of Physics & Munich School of BioEngineering, Technische Universität München, 85748, Garching, Germany
| | - Alexander A Fingerle
- Department of diagnostic and interventional Radiology, Technische Universität München, Munich, Germany
| | - Bernhard Brendel
- Philips GmbH Innovative Technologies, Research Laboratories, Hamburg, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics & Munich School of BioEngineering, Technische Universität München, 85748, Garching, Germany
| | - Ewald Roessl
- Philips GmbH Innovative Technologies, Research Laboratories, Hamburg, Germany
| | - Ernst J Rummeny
- Department of diagnostic and interventional Radiology, Technische Universität München, Munich, Germany
| | - Daniela Pfeiffer
- Department of diagnostic and interventional Radiology, Technische Universität München, Munich, Germany
| | - Roland Proksa
- Philips GmbH Innovative Technologies, Research Laboratories, Hamburg, Germany
| | - Philippe Douek
- Department of Interventional Radiology and Cardio-vascular and Thoracic Diagnostic Imaging, Louis Pradel University Hospital, Bron, France.,CREATIS, CNRS UMR 5220, INSERM U1206, INSA-Lyon, France
| | - Peter B Noël
- Department of diagnostic and interventional Radiology, Technische Universität München, Munich, Germany.,Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
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Zhou W, Lane JI, Carlson ML, Bruesewitz MR, Witte RJ, Koeller KK, Eckel LJ, Carter RE, McCollough CH, Leng S. Comparison of a Photon-Counting-Detector CT with an Energy-Integrating-Detector CT for Temporal Bone Imaging: A Cadaveric Study. AJNR Am J Neuroradiol 2018; 39:1733-1738. [PMID: 30093479 DOI: 10.3174/ajnr.a5768] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/19/2018] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND PURPOSE Evaluating abnormalities of the temporal bone requires high-spatial-resolution CT imaging. Our aim was to assess the performance of photon-counting-detector ultra-high-resolution acquisitions for temporal bone imaging and compare the results with those of energy-integrating-detector ultra-high-resolution acquisitions. MATERIALS AND METHODS Phantom studies were conducted to quantify spatial resolution of the ultra-high-resolution mode on a prototype photon-counting-detector CT scanner and an energy-integrating-detector CT scanner that uses a comb filter. Ten cadaveric temporal bones were scanned on both systems with the radiation dose matched to that of the clinical examinations. Images were reconstructed using a sharp kernel, 0.6-mm (minimum) thickness for energy-integrating-detector CT, and 0.6- and 0.25-mm (minimum) thicknesses for photon-counting-detector CT. Image noise was measured and compared using adjusted 1-way ANOVA. Images were reviewed blindly by 3 neuroradiologists to assess the incudomallear joint, stapes footplate, modiolus, and overall image quality. The ranking results for each specimen and protocol were compared using the Friedman test. The Krippendorff α was used for interreader agreement. RESULTS Photon-counting-detector CT showed an increase of in-plane resolution compared with energy-integrating-detector CT. At the same thickness (0.6 mm), images from photon-counting-detector CT had significantly lower (P < .001) image noise compared with energy-integrating-detector CT. Readers preferred the photon-counting-detector CT images to the energy-integrating-detector images for all 3 temporal bone structures. A moderate interreader agreement was observed with the Krippendorff α = 0.50. For overall image quality, photon-counting-detector CT image sets were ranked significantly higher than images from energy-integrating-detector CT (P < .001). CONCLUSIONS This study demonstrated substantially better delineation of fine anatomy for the temporal bones scanned with the ultra-high-resolution mode of photon-counting-detector CT compared with the ultra-high-resolution mode of a commercial energy-integrating-detector CT scanner.
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Affiliation(s)
- W Zhou
- From the Departments of Radiology (W.Z., J.I.L., M.R.B., R.J.W., K.K.K., L.J.E., C.H.M., S.L.)
| | - J I Lane
- From the Departments of Radiology (W.Z., J.I.L., M.R.B., R.J.W., K.K.K., L.J.E., C.H.M., S.L.)
| | - M L Carlson
- Otolaryngology-Head and Neck Surgery (M.L.C.)
| | - M R Bruesewitz
- From the Departments of Radiology (W.Z., J.I.L., M.R.B., R.J.W., K.K.K., L.J.E., C.H.M., S.L.)
| | - R J Witte
- From the Departments of Radiology (W.Z., J.I.L., M.R.B., R.J.W., K.K.K., L.J.E., C.H.M., S.L.)
| | - K K Koeller
- From the Departments of Radiology (W.Z., J.I.L., M.R.B., R.J.W., K.K.K., L.J.E., C.H.M., S.L.)
| | - L J Eckel
- From the Departments of Radiology (W.Z., J.I.L., M.R.B., R.J.W., K.K.K., L.J.E., C.H.M., S.L.)
| | - R E Carter
- Division of Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, Rochester, Minnesota
| | - C H McCollough
- From the Departments of Radiology (W.Z., J.I.L., M.R.B., R.J.W., K.K.K., L.J.E., C.H.M., S.L.)
| | - S Leng
- From the Departments of Radiology (W.Z., J.I.L., M.R.B., R.J.W., K.K.K., L.J.E., C.H.M., S.L.)
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