To assess intravascular density, overall image quality, and contrast medium (CM) injection pressure of CT coronary angiography (CTCA) examinations performed using iterative image reconstructionand an iodine concentration as low as 270mgI/mL in comparisonwith standard (320mgI/mL) iodine concentration CM.

Seventy­-three nonobese patients (body mass index <30kg/m2) underwent CTCA on a high definition 64­-row CT scanner (CT750 HD, General Electric, Milwaukee, WI). Out of them, in 38 patients (52%) 80-­90 of iodixanol270mgI/mLwere injected intravenously at 6.7mL/s flow rate,while in the remaining 35 (48%) the same volume of iodixanol320mgI/mLwas administered at 5.6mL/s flow rate, thusensuring an iodine delivery rate of 1.8gI/s in all cases ( Table 1 ).CM injection was followed by administration of 40mL of saline flush at the same flow rate to achieveoptimal bolus...

Mean arterial density and SNR were comparable between iodixanol 270mgI/mL and 320mgI/mL (508±86 vs 510±105, p=0.86 and 12.8±3.3 vs 14.1±6.0, p=0.71, respectively). Overall image quality was good and comparable with either iodixanol 270mgI/mL or 320mgI/mL (2.9±0.3 vs 2.8±0.2, p=0.89) ( Fig. 2 , Fig. 3 , Fig. 4 , Fig. 5 , Fig. 6 , Fig. 7 , Fig. 8 , Fig. 9 , Fig. 10 ). Injection pressure was significantly lower with iodixanol 270mgI/mL than with iodixanol 320mgI/mL (130±80 vs 221±58 psi, p<0.002). No...

CTCA with iterative image reconstruction can be successfully performed using an iodine concentration as low as 270mgI/mL with the advantage of a significantly lower injection pressure compared with standard (320mgI/mL) iodine CM. The combination of low iodine concentration, low tube voltage and adaptive statistical iterative image reconstruction allows reducing CM injection pressure,iodine load,and radiation exposure in CTCA of nonobesepatients.

Dr. Michela Gabelloni Department of Diagnostic and Interventional Radiology -University of Pisa Via Paradisa, 2 - 56100 Pisa, IT Email:[email protected]

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