Objectives: To compare native aortic (AV) and mitral valve (MV) image quality on limited-dose retrospectively ECG-gated CTA of the thoracoabdominal aorta reconstructed with iterative reconstruction (IR) and filtered back projection (FBP).
Methods: Fifty patients underwent routine care retrospectively ECG-gated thoracoabdominal limited-dose 256-slice CTA. At 30 % (systole) and 75 % (diastole) of the R-R interval AV and MV were reconstructed using FBP and IR. Objective image quality [density and noise (SD of density measurement)] was measured. Two independent observers scored subjective valve image quality using four-point Likert scales.
Results: IR significantly decreased image noise, but did not alter the aorta and interventricular septum density. Interobserver variability was moderate to good. Valve image quality was scored at least moderate in most cases. IR scored one or two Likert scale points higher than FBP in 10 (first observer) and 27 (second observer) scores. Conversely, IR scored one Likert scale point lower than FBP in 1 (first observer) and 4 (second observer) scores.
Conclusions: Limited-dose retrospectively ECG-gated thoracoabdominal CTA enables moderate to excellent evaluation of AV and MV in most patients, in addition to the primary diagnostic question. Image quality is further improved by IR.