Evaluation of a bolus-tracking method based on a pitch-correction formula for lower-extremity CT angiography

To assess the clinical utility of a novel scan-timing protocol Pitch Optimized Bolus Tracking (POBT) for lower-extremity CT angiography (CTA). The POBT method individualizes the helical pitch on the basis of patient-specific cardiac output, thereby maximizing arterial enhancement and limiting venous contamination. In this retrospective study, 75 patients who underwent lower-extremity CTA were divided into two groups. The POBT group (n = 39) employed a patient-specific pitch factor derived from echocardiographic stroke volume and heart rate, whereas the conventional bolus-tracking (BT) group (n = 36) used a fixed pitch. Quantitative and qualitative evaluations of arterial and venous contrast enhancement were performed at predefined anatomical levels. Relative to the conventional BT group, the POBT group exhibited significantly greater distal arterial enhancement (median, 302 HU vs. 265 HU; p < 0.05) and substantially lower venous contamination (5.1% vs. 31%; p < 0.05). Arterial image quality was rated "excellent" more frequently in the POBT group, with pronounced suppression of venous overlap. Contrast-medium volume did not differ between groups. The POBT method improves diagnostic performance in lower-extremity CTA by adapting the helical pitch to individual hemodynamics, thereby enhancing distal arterial visualization and mitigating venous contamination without increasing patient dose or contrast load.