Objective: The aim of our study was to assess the impact of body mass index (BMI) on image quality and diagnostic accuracy using dual-source computed tomography.
Subjects and Methods
Dual-source computed tomography and invasive coronary angiography were performed in 125 consecutive patients. Coronary segments were assessed for both image quality (1: excellent; 4: poor) and presence of significant vessel stenosis (_50%). Accuracy of lesion detection was calculated using invasive
coronary angiography as the standard of reference. The impact of BMI on image quality and accuracy was assessed by multivariate regression and between subgroups of BMI.
Results
Mean BMI in our study was 28.4 ±4.1 kg/m2. In multivariate regression, BMI was proved to have a significant and independent impact on image quality (P = 0.009). Similarly, the latter was significantly degraded in a subgroup of patients with BMI≥30 kg/m2 (P < 0.05). Although the proportion of segments with diagnostic image quality was equal in all BMI subgroups, linear regression suggested 25 kg/m2 as the cut-off until which excellent or good image quality can be achieved. Sensitivity, specificity, positive, and negative predictive values were 91.6%, 93%, 75.2%, and 97.9% on a per-segment and 100%, 77.5%, 90.4%, and 100% on a per-patient level. In both multivariate analysis and comparison of subgroups, there was no significant effect of BMI on the persegment diagnostic accuracy.
Invest Radiol 2008;43: 712–718
One of the most important prerequisites for a diagnostic image quality in non-invasive CT imaging of the heart is the accurate patient selection. It is well know, that obesity has an impact of image quality, due to an impaired signal- to noise ratio.
Brodoevel et al could show in this study, that image quality is best in thinner patients (BMI < 25 kg/m²). However, diagnostic image quality can also be achieved in pts with a body mass index > 30 kg/m².