Effects of Test-Bolus and Low-Dose Scan on Ct Pulmonary Angiography Image Quality in Patients With Different Body Mass Indexes

Abstract

This study aimed to investigate different methods of obtaining high-quality Computed Tomography pulmonary angiography (CTPA) images using low-dose scanning in patients with different body mass index (BMI) values. Sixty patients with suspected pulmonary embolism were grouped based on their BMI values (BMI < 25, designated N, and BMI ≥ 25, designated O) and were assigned to receive either test bolus (TB) or bolus tracking (BT) at conventional (C) or low (L) dose. The effective dose (ED) in the N–TB–L group was lower than in the group N–TB–C (0.56 ± 0.05 vs. 3.78 ± 1.16, p < 0.001), with similar image quality (4.90 ± 0.31 vs. 4.70 ± 0.47, p = 0.120). The ED in the O–TB–L group was lower than in the O–TB–C group (0.54 ± 0.03 vs. 5.14 ± 1.34, p < 0.001), but the group O–TB–C’s image quality was higher (4.65 ± 0.59 vs. 3.95 ± 0.89, p = 0.006). Groups N–TB–L versus O–TB–L, groups N-TB-L versus N–BT-L and groups O–TB–C versus O–BT–C had similar EDs (all ps > 0.05), but the image quality was different (all ps < 0.05). In conclusion, the results showed that the image quality of low-dose CTPA scanning using TB was similar to that of the conventional-dose CTPA in patients with BMI < 25 but was lower in patients with BMI ≥ 25. TB was better than BT for all patients, regardless of BMI, when receiving the same ED.