Florian André1, Philipp Fortner2, Mani Vembar3, Dirk Mueller4, Wolfram Stiller5, Sebastian J Buss6, Hans-Ulrich Kauczor5, Hugo A Katus2, Grigorios Korosoglou2. 1. University of Heidelberg, Department of Cardiology, Angiology and Pneumology, Im Neuenheimer Feld 410, Heidelberg, 69120, Germany. Electronic address: florian.andre@med.uni-heidelberg.de. 2. University of Heidelberg, Department of Cardiology, Angiology and Pneumology, Im Neuenheimer Feld 410, Heidelberg, 69120, Germany. 3. CT Clinical Science, Philips Healthcare, c595 Miner Road, Cleveland, OH 44143, USA. 4. CT Clinical Science, Philips Healthcare, Luebeckertordamm 5, Hamburg, 20099, Germany. 5. University of Heidelberg, Department of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 410, Heidelberg, 69120, Germany. 6. University of Heidelberg, Department of Cardiology, Angiology and Pneumology, Im Neuenheimer Feld 410, Heidelberg, 69120, Germany; Das Radiologische Zentrum - Radiology Center, Sinsheim-Eberbach-Erbach-Walldorf-Heidelberg, Rohrbacher Straße 149, Heidelberg, 69126, Germany.
Abstract
BACKGROUND: The aim of this study was to assess the potential for radiation dose reduction using knowledge-based iterative model reconstruction (K-IMR) algorithms in combination with ultra-low dose body mass index (BMI)-adapted protocols in coronary CT angiography (coronary CTA). METHODS:Forty patients undergoing clinically indicated coronary CTA were randomly assigned to two groups with BMI-adapted (I: <25.0 kg/m2, II: <28.0 kg/m2, III: <30.0 kg/m2, IV: ≥30.0 kg/m2) low dose (LD, I: 100kVp/75 mAs, II: 100kVp/100 mAs, III: 100kVp/150 mAs, IV: 120kVp/150 mAs, n = 20) or ultra-low dose (ULD, I: 100kVp/50 mAs, II: 100kVp/75 mAs, III: 100kVp/100 mAs, IV: 120kVp/100 mAs, n = 20) protocols. Prospectively-triggered coronary CTA was performed using a 256-MDCT with the lowest reasonable scan length. Images were generated with filtered back projection (FBP), a noise-reducing hybrid iterative algorithm (iD, levels 2/5) and K-IMR using cardiac routine (CR) and cardiac sharp settings, levels 1-3. RESULTS: Groups were comparable regarding anthropometric parameters, heart rate, and scan length. The use of ULD protocols resulted in a significant reduction of radiation exposure (0.7 (0.6-0.9) mSv vs. 1.1 (0.9-1.7) mSv; p < 0.02). Image quality was significantly better in the ULD group using K-IMR CR 1 compared to FBP, iD 2 and iD 5 in the LD group, resulting in fewer non-diagnostic coronary segments (2.4% vs. 11.6%, 9.2% and 6.1%; p < 0.05). CONCLUSIONS: The combination of K-IMR with BMI-adapted ULD protocols results in significant radiation dose savings while simultaneously improving image quality compared to LD protocols with FBP or hybrid iterative algorithms. Therefore, K-IMR allows for coronary CTA examinations with high diagnostic value and very low radiation exposure in clinical routine.
RCT Entities:
BACKGROUND: The aim of this study was to assess the potential for radiation dose reduction using knowledge-based iterative model reconstruction (K-IMR) algorithms in combination with ultra-low dose body mass index (BMI)-adapted protocols in coronary CT angiography (coronary CTA). METHODS: Forty patients undergoing clinically indicated coronary CTA were randomly assigned to two groups with BMI-adapted (I: <25.0 kg/m2, II: <28.0 kg/m2, III: <30.0 kg/m2, IV: ≥30.0 kg/m2) low dose (LD, I: 100kVp/75 mAs, II: 100kVp/100 mAs, III: 100kVp/150 mAs, IV: 120kVp/150 mAs, n = 20) or ultra-low dose (ULD, I: 100kVp/50 mAs, II: 100kVp/75 mAs, III: 100kVp/100 mAs, IV: 120kVp/100 mAs, n = 20) protocols. Prospectively-triggered coronary CTA was performed using a 256-MDCT with the lowest reasonable scan length. Images were generated with filtered back projection (FBP), a noise-reducing hybrid iterative algorithm (iD, levels 2/5) and K-IMR using cardiac routine (CR) and cardiac sharp settings, levels 1-3. RESULTS: Groups were comparable regarding anthropometric parameters, heart rate, and scan length. The use of ULD protocols resulted in a significant reduction of radiation exposure (0.7 (0.6-0.9) mSv vs. 1.1 (0.9-1.7) mSv; p < 0.02). Image quality was significantly better in the ULD group using K-IMR CR 1 compared to FBP, iD 2 and iD 5 in the LD group, resulting in fewer non-diagnostic coronary segments (2.4% vs. 11.6%, 9.2% and 6.1%; p < 0.05). CONCLUSIONS: The combination of K-IMR with BMI-adapted ULD protocols results in significant radiation dose savings while simultaneously improving image quality compared to LD protocols with FBP or hybrid iterative algorithms. Therefore, K-IMR allows for coronary CTA examinations with high diagnostic value and very low radiation exposure in clinical routine.