Diagnostic confidence and image quality of CT pulmonary angiography at 100 kVp in overweight and obese patients

•We assessed quality and diagnostic confidence with 100 kVp CTPA at high body weight•Results in 75–99 kg, 100–125 kg and >125 kg groups were compared (216 patients)•Subjective quality and confidence did not differ between the body weight groups•Diagnostic confidence in non-obese and obese patients was not different either•CTPA at 100 kVp provides good quality and diagnostic confidence in patients <125kg; >125kg is unknown

AimTo compare image quality and diagnostic confidence of 100 kVp CT pulmonary angiography (CTPA) in patients with body weights (BWs) below and above 100 kg.Materials and methodsThe present retrospective study comprised 216 patients (BWs of 75–99 kg, 114 patients; 100–125 kg, 88 patients; >125 kg, 14 patients), who received 100 kVp CTPA to exclude pulmonary embolism. The attenuation was measured and the contrast-to-noise ratio (CNR) was calculated in the pulmonary trunk. Size-specific dose estimates (SSDEs) were evaluated. Three blinded radiologists rated subjective image quality and diagnostic confidence. Results between the BW groups and between three body mass index (BMI) groups (BMI <25 kg/m2, BMI = 25–29.9 kg/m2, and BMI ≥30 kg/m2, i.e., normal weight, overweight, and obese patients) were compared using the Kruskal–Wallis test.ResultsVessel attenuation was higher and SDDE was lower in the 75–99 kg group than at higher BWs (p-values between <0.001 and 0.03), with no difference between the 100–125 and >125 kg groups (p = 0.892 and 1). Subjective image quality and diagnostic confidence were not different among the BW groups (p = 0.225 and 1). CNR was lower (p < 0.006) in obese patients than in normal weight or overweight subjects. Diagnostic confidence was not different in the BMI groups (p = 0.105).ConclusionCTPA at 100 kVp tube voltage can be used in patients weighing up to 125 kg with no significant deterioration of subjective image quality and confidence. The applicability of 100 kVp in the 125–150 kg BW range needs further testing in larger collectives.