OBJECTIVE: The objective of our study was to compare the spatial resolution and effective dose from 64-MDCT with several published CT urography protocols. MATERIALS AND METHODS: A phantom containing 1-, 2-, or 4-mm cylindric channels to simulate ureters with 0.25- to 3-mm plugs to simulate ureteral filling defects or ureteral diverticula was imaged using eight helical CT urography protocols. Computed radiography (CR) was also performed. Coronal maximum-intensity-projection images were created and, with the CR image, were evaluated independently by two genitourinary radiologists. Spatial resolution was evaluated by scoring each abnormality as present, visible; or as absent, not visible. Effective dose estimates for 11 CT urography protocols, including the radiographs obtained in the CT urography protocol, were calculated using published Monte Carlo organ dose coefficients. RESULTS: All ureteral abnormalities detected on CR were detected on the highest-spatial-resolution reconstruction using the evaluated 64-MDCT system. The smallest filling defect identified by both was 0.25 mm. Three 0.25-mm filling defects were not detected using the evaluated 16-MDCT system. The 4-MDCT system protocols showed the poorest performance. The range of effective doses for the evaluated CT urography protocols was 20.1-66.3 mSv. The number of phases, anatomic coverage per phase, and scanning parameters all contributed to this variation in dose. CONCLUSION: The evaluated 64-MDCT system showed detection accuracy identical to that of CR. Limiting anatomic coverage for specific phases and combining phases can reduce dose for multiphase protocols by up to a factor of 2 relative to early (circa 2000) 4-MDCT.
OBJECTIVE: The objective of our study was to compare the spatial resolution and effective dose from 64-MDCT with several published CT urography protocols. MATERIALS AND METHODS: A phantom containing 1-, 2-, or 4-mm cylindric channels to simulate ureters with 0.25- to 3-mm plugs to simulate ureteral filling defects or ureteral diverticula was imaged using eight helical CT urography protocols. Computed radiography (CR) was also performed. Coronal maximum-intensity-projection images were created and, with the CR image, were evaluated independently by two genitourinary radiologists. Spatial resolution was evaluated by scoring each abnormality as present, visible; or as absent, not visible. Effective dose estimates for 11 CT urography protocols, including the radiographs obtained in the CT urography protocol, were calculated using published Monte Carlo organ dose coefficients. RESULTS: All ureteral abnormalities detected on CR were detected on the highest-spatial-resolution reconstruction using the evaluated 64-MDCT system. The smallest filling defect identified by both was 0.25 mm. Three 0.25-mm filling defects were not detected using the evaluated 16-MDCT system. The 4-MDCT system protocols showed the poorest performance. The range of effective doses for the evaluated CT urography protocols was 20.1-66.3 mSv. The number of phases, anatomic coverage per phase, and scanning parameters all contributed to this variation in dose. CONCLUSION: The evaluated 64-MDCT system showed detection accuracy identical to that of CR. Limiting anatomic coverage for specific phases and combining phases can reduce dose for multiphase protocols by up to a factor of 2 relative to early (circa 2000) 4-MDCT.
Authors: M R K Mookiah; A Rohrmeier; M Dieckmeyer; K Mei; F K Kopp; P B Noel; J S Kirschke; T Baum; K Subburaj Journal: Osteoporos Int Date: 2018-01-10 Impact factor: 4.507
Authors: Naoki Takahashi; Terri J Vrtiska; Akira Kawashima; Robert P Hartman; Andrew N Primak; Joel G Fletcher; Cynthia H McCollough Journal: Radiology Date: 2010-07 Impact factor: 11.105
Authors: Amy E Krambeck; John C Lieske; Xujian Li; Eric J Bergstralh; Andrew D Rule; David Holmes; Cynthia M McCollough; Terri J Vrtiska Journal: Urology Date: 2013-06-20 Impact factor: 2.649