Rolf Symons1, Yves De Bruecker2, John Roosen3, Laurent Van Camp4, Tyler E Cork5, Steffen Kappler6, Stefan Ulzheimer6, Veit Sandfort7, David A Bluemke8, Amir Pourmorteza9. 1. Radiology and Imaging Sciences - National Institutes of Health Clinical Center, Bethesda, MD, USA; Department of Imaging & Pathology, University Hospitals Leuven, Leuven, Belgium. 2. Department of Radiology, Imelda Hospital, Bonheiden, Belgium. 3. Department of Cardiology, Imelda Hospital, Bonheiden, Belgium. 4. Department of Imaging & Pathology, University Hospitals Leuven, Leuven, Belgium. 5. Radiology and Imaging Sciences - National Institutes of Health Clinical Center, Bethesda, MD, USA; Departments of Radiological Sciences and Bioengineering, University of California, Los Angeles, CA, USA. 6. Siemens Healthcare GmbH, Forchheim, Germany. 7. Radiology and Imaging Sciences - National Institutes of Health Clinical Center, Bethesda, MD, USA. 8. Radiology and Imaging Sciences - National Institutes of Health Clinical Center, Bethesda, MD, USA; Department of Radiology, University of Wisconsin Madison, Madison, WI, USA. 9. Radiology and Imaging Sciences - National Institutes of Health Clinical Center, Bethesda, MD, USA; Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA. Electronic address: amir.pourmorteza@emory.edu.
Abstract
PURPOSE: To evaluate the performance and clinical feasibility of 0.25 mm resolution mode of a dual-energy photon-counting detector (PCD) computed tomography (CT) system for coronary stent imaging and to compare the results to state-of-the-art dual-energy energy-integrating detector (EID) CT. MATERIALS AND METHODS: Coronary stents with different diameters (2.0-4.0 mm) were examined inside a coronary artery phantom consisting of plastic tubes filled with iodine-based and gadolinium-based contrast material diluted to approximate clinical concentrations (n = 18). EID images were acquired using 2nd and 3rd generation dual-source CT systems (SOMATOM Flash and SOMATOM Force, Siemens Healthcare) at 0.60 mm (defined as standard-resolution (SR)) isotropic voxel size. Radiation-dose matched PCD images were acquired using a human prototype PCD system (Siemens Healthcare) at 0.50 mm (SR) and 0.25 mm (HR) imaging modes. Images were reconstructed using optimized convolution kernels. RESULTS: Dual-energy HR PCD images significantly better stent lumen visualization (median: 69.5%, IQR: 61.2-78.9%) over dual-energy EID, and standard-resolution PCD images (median: 53.2-57.4%, all P < 0.01). HR PCD acquisitions reconstructed at SR image voxel size showed 25.3% lower image noise compared to SR PCD acquisitions (P < 0.001). High-resolution iodine and gadolinium maps, as well as virtual monoenergetic images, were calculated from the PCD data and enabled estimation of contrast agent concentration in the lumen without interference from the coronary stent. CONCLUSION: HR spectral PCD imaging significantly improves coronary stent lumen visibility over dual-energy EID. When the PCD-HR data was reconstructed into standard voxel sizes (0.5 mm isotropic) the image noise decreased by 25% compared to SR acquisition of PCD. Both dual-energy systems were consistent in estimating contrast agent concentrations.
PURPOSE: To evaluate the performance and clinical feasibility of 0.25 mm resolution mode of a dual-energy photon-counting detector (PCD) computed tomography (CT) system for coronary stent imaging and to compare the results to state-of-the-art dual-energy energy-integrating detector (EID) CT. MATERIALS AND METHODS: Coronary stents with different diameters (2.0-4.0 mm) were examined inside a coronary artery phantom consisting of plastic tubes filled with iodine-based and gadolinium-based contrast material diluted to approximate clinical concentrations (n = 18). EID images were acquired using 2nd and 3rd generation dual-source CT systems (SOMATOM Flash and SOMATOM Force, Siemens Healthcare) at 0.60 mm (defined as standard-resolution (SR)) isotropic voxel size. Radiation-dose matched PCD images were acquired using a human prototype PCD system (Siemens Healthcare) at 0.50 mm (SR) and 0.25 mm (HR) imaging modes. Images were reconstructed using optimized convolution kernels. RESULTS: Dual-energy HR PCD images significantly better stent lumen visualization (median: 69.5%, IQR: 61.2-78.9%) over dual-energy EID, and standard-resolution PCD images (median: 53.2-57.4%, all P < 0.01). HR PCD acquisitions reconstructed at SR image voxel size showed 25.3% lower image noise compared to SR PCD acquisitions (P < 0.001). High-resolution iodine and gadolinium maps, as well as virtual monoenergetic images, were calculated from the PCD data and enabled estimation of contrast agent concentration in the lumen without interference from the coronary stent. CONCLUSION: HR spectral PCD imaging significantly improves coronary stent lumen visibility over dual-energy EID. When the PCD-HR data was reconstructed into standard voxel sizes (0.5 mm isotropic) the image noise decreased by 25% compared to SR acquisition of PCD. Both dual-energy systems were consistent in estimating contrast agent concentrations.
Authors: Joakim da Silva; Fredrik Grönberg; Björn Cederström; Mats Persson; Martin Sjölin; Zlatan Alagic; Robert Bujila; Mats Danielsson Journal: J Med Imaging (Bellingham) Date: 2019-10-15
Authors: Jayasai R Rajagopal; Faraz Farhadi; Taylor Richards; Moozhan Nikpanah; Pooyan Sahbaee; Sujata M Shanbhag; W Patricia Bandettini; Babak Saboury; Ashkan A Malayeri; William F Pritchard; Elizabeth C Jones; Ehsan Samei; Marcus Y Chen Journal: Radiol Cardiothorac Imaging Date: 2021-10-28