Optimization of wrist tendon detection in virtual monochromatic images using dual energy-computed tomography.

Abstract

To evaluate the depiction of wrist tendons in virtual monochromatic images (VMIs) during a dual-energy CT (DE-CT) with the VMI image of conventional equivalent to 120kVp. Using Catphan600 and phantom analysis software for CT evaluation, measurements of VMI in a DE-CT were performed corresponding to the tube voltages of single-energy CT at 120kVp. Using a Discovery CT750 HD CT scanner (GE Healthcare) with DE-CT technology, 73 patients were scanned. We calculated the CT number, image noise, visual score, and contrast noise ratio (CNR) at the extensor pollicis tendon, extensor digitorum tendon, and flexor tendon in 11 VMIs from the DE-CT and VMI image of conventional equivalent to 120kVp. The results from the optimal VMIs were then compared with that of the VMI image of the conventional equivalent to 120kVp. The highest CT number and CNR for the tendon were for the 140keV VMI in the DE-CT compared to the other energy levels. There were significantly higher CT numbers, CNR values, and visual scores for each tendon at 140keV VMI with the DE-CT (p < 0.01) compared with a VMI image of conventional equivalent to 120kVp. Energy level of the VMIs during DE-CT for the best wrist tendon delineation was 140keV. This value of 140keV for the DE-CT was significantly higher than the CT number and CNR for the extensor pollicis, extensor digitorum, and flexor tendon compared with a VMI image of conventional equivalent to 120kVp.