Comparability of Echographic and Tomographic Assessments of Body Fat Changes Related to the HIV Associated Adipose Redistribution Syndrome (HARS) in Antiretroviral Treated Patients

Abstract 

To assess the comparability of ultrasonographic (US) subcutaneous fat thickness (SFT) measurements in comparison with computed tomography (CT) at reference points (RPs) representative of HIV related adipose redistribution syndrome (HARS) in patients treated with antiretrovirals. US and CT measurements were compared in nine patients with clinical reports of HARS. We obtained the best resolution of facial (at deepest point of Bichat pad), brachial (in the dorsal face of arm) and crural SFT (at mid thigh) by means of minimal transducer pressures avoiding potential biases such as stand off pads pressure on the skin and artefacts due to too abundant quantity of gel. CT scans were obtained in the same RP where US measurements were performed such as identified by means of metallic skin markers. Median US measurement of facial SFT was 8.8 mm (95% CI: 3.1 to 13.4), 3.95 mm (95% CI: 2.62 to 5.84) for brachial SFT and 4 mm (95% CI: 3.4 to 9.4) for crural SFT. Median CT assessments of facial SFT was 8.7 mm (95% CI: 3.5 to 13.5), 4.2 mm (95% CI: 2.6 to 5.88) for brachial SFT and 5 mm (95% CI: 3.9 to 10.3) for crural SFT, with no significant difference at each RP. A linear regression showed good CT/US comparability at each RP, with no significant deviation from linearity (p > 0.10). US shows to be highly comparable with CT, excluding invaliding biases as the transducer pressure on the skin. Given the proven efficacy on the HARS assessments, if well standardized, US could be a reliable method, simpler than CT in the management of body fat changes related to HARS. (E-mail: steinman@imaging.robarts.ca)

Key Words: Ultrasonography, Lipodystrophy, HIV infection, Antiretrovirals, Body fat changes