Improved noninvasive coronary angiography in morbidly obese patients with dual-source computed tomography

Background

Morbidly obese persons (body mass index [BMI; in kg/m²] ≥ 40) have an increased risk of cardiovascular morbidity and mortality but have reduced accuracy with conventional cardiac testing and coronary CT angiography (CCTA).

Objective

This study investigated a novel dual-source computed tomography (DSCT) acquisition and reconstruction method for coronary imaging in morbidly obese patients.

Methods

This was a observational study in which each patient served as his or her own control. After a single DSCT acquisition using a novel method, standard quarter-scan image reconstructions at a temporal resolution of 83 milliseconds were compared with temporal resolution reconstructions at 105, 125, and 165 milliseconds. Images were evaluated for diagnostic adequacy score and for image noise, signal-to-noise ratio, and contrast-to-noise ratio. In each patient, the image reconstruction with the best visual diagnostic score was compared with the control image for quantitative measures.

Results

Fifty patients (32 female; mean ± SD age, 51 ± 10 y; mean BMI, 44.8 ± 5.6) were enrolled. Scans were of diagnostic quality in 47 (94%) patients using the “best reconstruction” compared with 38 (76%) patients using quarter-scan reconstruction. Significant improvements were observed in noise (42 ± 16 HU versus 56 ± 19 HU; P < 0.0001), contrast-to-noise ratio (8.4 ± 3.3 HU versus 7.0 ± 2.2 HU; P = 0.0038), and signal-to-noise ratio (7.6 ± 2.9 HU versus 6.5 ± 3.5 HU; P = 0.030).

Conclusions

CCTA with DSCT using a modified scan protocol and adjustable temporal reconstructions provides diagnostic image quality in >90% of morbidly obese patients.

Keywords: Coronary CT angiography, Dual-source CT, Morbidly obese, Reconstruction