Image quality of low-dose CCTA in obese patients: impact of high-definition computed tomography and adaptive statistical iterative reconstruction

The accuracy of coronary computed tomography angiography (CCTA) in obese persons is compromised by increased image noise. We investigated CCTA image quality acquired on a high-definition 64-slice CT scanner using modern adaptive statistical iterative reconstruction (ASIR). Seventy overweight and obese patients (24 males; mean age 57years, mean body mass index 33kg/m2) were studied with clinically-indicated contrast enhanced CCTA. Thirty-five patients underwent a standard definition protocol with filtered backprojection reconstruction (SD-FBP) while 35 patients matched for gender, age, body mass index and coronary artery calcifications underwent a novel high definition protocol with ASIR (HD-ASIR). Segment by segment image quality was assessed using a four-point scale (1=excellent, 2=good, 3=moderate, 4=non-diagnostic) and revealed better scores for HD-ASIR compared to SD-FBP (1.5±0.43 vs. 1.8±0.48; p<0.05). The smallest detectable vessel diameter was also improved, 1.0±0.5mm for HD-ASIR as compared to 1.4±0.4mm for SD-FBP (p<0.001). Average vessel attenuation was higher for HD-ASIR (388.3±109.6 versus 350.6±90.3 Hounsfield Units, HU; p