Evaluating CMR

Measuring Intra-abdominal Fat Using MRI and CT

MRI and CT are the only in vivo methods available to directly and accurately quantify intra-abdominal fat. Intra-abdominal fat is the fat located within the abdominal muscle wall that surrounds the organs (or viscera). On average, it accounts for only 12% and 5% of total body fat in men and women, respectively (Figure 3). As with skeletal muscle, measuring intra-abdominal fat with multiple images is costly, labour intensive, and in the case of CT, involves substantial radiation exposure. Consequently, intra-abdominal fat is normally assessed using a single MRI or CT image at L4-L5. However, it is important to note that intra-abdominal fat values obtained through CT are not necessarily comparable to those obtained through MRI (16, 17).