RELATIONSHIP BETWEEN VOLUMES AND AREAS FROM SINGLE TRANSVERSE SCANS OF INTRAABDOMINAL FAT MEASURED BY MAGNETIC-RESONANCE-IMAGING

OBJECTIVE: To determine the level of a single transverse scan of intra -abdominal fat between L1 and L5 vertebrae that best predicts intra-ab dominal fat volumes. SUBJECTS: Sixteen male and seven female patients with non-insulin-dependent diabetes mellitus, aged 44-74 y. OUTCOME ME ASURES: Volumes and areas from single scans of intra-abdominal fat mea sured by magnetic resonance imaging with a 1.5 Tesla magnetic field st rength. RESULTS: Intra-abdominal fat volumes and masses were calculate d from fat areas from eight cross-sectional transverse single scans (n ine scans in eight men) of 20 mm thickness. Men and women, respectivel y, had mean body mass index (BMI) of 27.9 (s.d. 3.0) and 31.6 (s.d. 4. 7) kg/m(2), and intra-abdominal fat of 2.3 (s.d. 0.5) and 2.5 (s.d. 0. 6) kg. Intra-abdominal fat area of the fourth scan (in the direction o f L1 to L5) gave the highest prediction of total intra-abdominal fat b oth in men (r = 0.959, P < 0.001) and in women (r = 0.973, P < 0.001). The intra-abdominal fat area of the third scan gave almost as good a prediction. These third and fourth scans corresponded to L2 and L3 ver tebrae. The intra-abdominal fat areas from the sixth and seventh scans , corresponded to the frequently used L4-L5 and had lower correlations with intra-abdominal fat. There were no gender differences in the pre diction of volumes from areas of intra-abdominal fat. Intra-abdominal fat areas of the fourth scan explained 93% of variance (SEE = 0.14 kg) of total intra-abdominal fat for both genders: intra-abdominal fat (k g) = 0.0108 x intra-abdominal fat area of the fourth scan (cm(2)) + 0. 244. CONCLUSIONS: In large studies of intra-abdominal fat, using magne tic resonance imaging (MR() or computerised tomography scanning, a sin gle intra-abdominal fat area at the intervertebral disc between L2 and L3 vertebrae offers a cheaper, faster and safer method, with high pre diction of total intra-abdominal fat volumes and masses.