Anatomical and CT approach of the adipose tissue: application in morbid obesity

The importance and proportion of visceral adipose tissue (VAT) represent the best criterion to define obesity. Because VAT value is difficult to obtain in clinical practice, the indication for bariatric surgery is still based at present on Body Mass index (BMI), even though BMI is a poor predictor of obesity-related morbid complications. This correlation study aimed at determining a simple and accurate computed tomography (CT) anatomic marker, which can be easily used clinically, well correlated with the volume of VAT and consequently with morbid complications.

We studied 108 CT scans of patients presenting with morbid obesity. Several simplified measures (external and internal abdominal diameters and circumferences) were conducted on CT scan view, going through the fourth lumbar vertebra (L4), in addition to various vertebral measurements (area of the vertebra, sagittal and transversal diameters), VAT and subcutaneous adipose tissue (SAT). Then, we reported the simplified measures values on the vertebral areas, and we calculated the Bertin index. Finally, we conducted a correlation study between all variables to obtain accurate VAT measurements.

The internal abdominal circumference and the Bertin index showed the best correlations with VAT in morbidly obese patients (r = 0.84 and 0.85, respectively). BMI and anthropometric measures were not correlated with VAT.

CT scan study allows to simply approximate VAT value in morbidly obese patients. An abdominal CT scan could be part of the tests used in the evaluation of obese patients to base therapeutic strategies on VAT values and not on BMI as it is the case today.