Nonenhancing Tissue on MR Imaging of Pedal Infection

Abstract
OBJECTIVE. We studied the frequency, location, extent, and signal characteristics of nonenhancing tissue in pedal infections and correlated those areas with surgical and histologic findings.MATERIALS AND METHODS. One hundred ten contrast-enhanced 1.5-T MR imaging foot examinations in 102 patients (28 women, 74 men; mean age, 59 years), 82% of whom had diabetes mellitus, were reviewed by two musculoskeletal radiologists for the presence of areas without recognizable enhancement. The number, size, location, signal characteristics, and enhancement ratio of nonenhancing regions were noted. MR imaging findings were compared with surgical and histology reports.RESULTS. Nonenhancing regions were found in 27 feet (24.5%, 96.3% in diabetic patients, p = 0.032) at the forefoot (n = 16), toes (n = 8), and heel (n = 3). The mean size of the nonenhancing regions was 4.1 × 2.7 × 1.4 cm. Signal characteristics on T1-weighted images were isointense to muscle (n = 21, 77.8%), hypointense to muscle (n = 3, 11.1%), heteroge...