A Qurashi1, L Rainford2, A Ajlan3, K Khashoggi3, L Ashkar3, M Al-Raddadi4, M Al-Ghamdi5, M Al-Thobaiti6, S Foley2. 1. Radiography and Diagnostic Imaging, School of Medicine, University College Dublin, Ireland; Faculty of Applied Medical Sciences, Taibah University, Madinah, Saudi Arabia. Electronic address: abdulazizqurashi1@gmail.com. 2. Radiography and Diagnostic Imaging, School of Medicine, University College Dublin, Ireland. 3. King Abdulaziz University, Jeddah, Saudi Arabia. 4. King Fahad Hospital, Madinah, Saudi Arabia. 5. King Abdulaziz Hospital, Jeddah, Saudi Arabia. 6. King Abdulaziz Medical City, Jeddah, Saudi Arabia.
Abstract
INTRODUCTION: This study investigated the impact of different protocols on radiation dose and image quality for obese patients undergoing abdominal CT examinations. METHODS: Five abdominal/pelvis CT protocols employed across three scanners from a single manufacturer in a single centre used a variety of parameters (kV: 100/120, reference mAs: 150/190/218/250/300, image reconstruction: filtered back projection (FBP)/iterative (IR)). The routine protocol employed 300 reference mAs and 120 kV. Data sets resulting from obese patient examinations (n = 42) were assessed for image quality using visual grading analysis by three experienced radiologists. Objective assessment (noise, signal/contrast-noise ratios) and radiation dose was compared to determine optimal protocols for prospective testing on a further sample of patients (n = 47) for scanners using FBP and IR techniques. RESULTS: Compared to the routine protocol, mean radiation dose was reduced by 60% when using 100 kV and SAFIRE technique strength 3 (p = 0.001). Reduction of up to 30% in radiation dose was noted for the FBP protocol: 120 kV and 190 reference mAs (p = 0.008). Subjective and objective image quality for both protocols were comparable to that of the routine protocol (p > 0.05). An overall improvement in image quality with increasing strength of SAFIRE was noted. Upon clinical implementation of the optimal dose protocols, local radiology consensus deemed image quality to be acceptable for the participating obese patient cohort. CONCLUSION: Radiation dose for obese patients can be optimised whilst maintaining image quality. Where iterative reconstruction is available relatively low kV and quality reference mAs are also viable for imaging obese patients at 30-60% lower radiation doses.
INTRODUCTION: This study investigated the impact of different protocols on radiation dose and image quality for obesepatients undergoing abdominal CT examinations. METHODS: Five abdominal/pelvis CT protocols employed across three scanners from a single manufacturer in a single centre used a variety of parameters (kV: 100/120, reference mAs: 150/190/218/250/300, image reconstruction: filtered back projection (FBP)/iterative (IR)). The routine protocol employed 300 reference mAs and 120 kV. Data sets resulting from obesepatient examinations (n = 42) were assessed for image quality using visual grading analysis by three experienced radiologists. Objective assessment (noise, signal/contrast-noise ratios) and radiation dose was compared to determine optimal protocols for prospective testing on a further sample of patients (n = 47) for scanners using FBP and IR techniques. RESULTS: Compared to the routine protocol, mean radiation dose was reduced by 60% when using 100 kV and SAFIRE technique strength 3 (p = 0.001). Reduction of up to 30% in radiation dose was noted for the FBP protocol: 120 kV and 190 reference mAs (p = 0.008). Subjective and objective image quality for both protocols were comparable to that of the routine protocol (p > 0.05). An overall improvement in image quality with increasing strength of SAFIRE was noted. Upon clinical implementation of the optimal dose protocols, local radiology consensus deemed image quality to be acceptable for the participating obesepatient cohort. CONCLUSION: Radiation dose for obesepatients can be optimised whilst maintaining image quality. Where iterative reconstruction is available relatively low kV and quality reference mAs are also viable for imaging obesepatients at 30-60% lower radiation doses.