CT diagnostics of pulmonary embolism: Does iodine delivery rate still affect image quality in iterative reconstruction?

Abstract

BACKGROUND\nComputed tomographic (CT) imaging in suspected pulmonary artery embolism represents the standard procedure. Studies without iterative reconstruction proved beneficial using increased iodine delivery rate (IDR). This study compares image quality in pulmonary arteries on iteratively reconstructed CT images of patients with suspected pulmonary embolism using different IDR.\n\n\nMATERIAL AND METHODS\n1065 patients were included in the study. Patients in group A (n\u200a=\u200a493) received an iodine concentration of 40\u200ag/100\u200aml (IDR 1.6\u200ag/s) and patients in group B (n\u200a=\u200a572) an iodine concentration of 35\u200ag/100\u200aml (IDR 1.4\u200ag/s) at a flow rate of 4\u200aml/s. Two 80-detector spiral CT scanners with iterative reconstruction were used. We measured mean density values in truncus pulmonalis, both pulmonary arteries and segmental pulmonary arteries. Subjectively, the contrast of apical and basal pulmonary arteries was determined on a 4-point Likert scale.\n\n\nRESULTS\nRadiodensity was significantly higher in all measured pulmonary arteries using the increased IDR (p\u200a< \u200a0.001). TP: 483.0 HU vs. 393.4 HU; APD: 452.1 HU vs. 372.1 HU; APS: 448.2 HU vs. 374.4 HU; ASP: 443.9 vs. 374.4 HU. Subjectively assessed contrast enhancement in apical (p\u200a=\u200a0.077) and basal (p\u200a=\u200a0.429) lung sections showed no significant differences.\n\n\nCONCLUSION\nHigher IDR improves objective image quality in all patients with significantly higher radiodensities by iterative reconstruction. Subjective contrast of apical and basal lung sections did not differ. The number of non-sufficient scans decreased with high IDR.