Intravertebral fat measurement with quantitative CT in patients with Cushing disease and anorexia nervosa.

Dual-energy quantitative computed tomography can be used to calculate the intravertebral fat content as well as to correct the effect of intravertebral fat on bone density measurements. The authors studied seven female patients with Cushing syndrome and 15 female patients with anorexia nervosa--conditions known to result in abnormalities of somatic fat distribution--to determine whether the intravertebral fat content was normal and whether it reflected somatic fat quantities. Intravertebral fat content could not be predicted on the basis of somatic fat, weight, or bone mineral content. Intravertebral fat content was elevated in patients with anorexia nervosa (compared with normal values in young female volunteers). In patients with anorexia, the amount of fat increase was disproportionately large for the severity of osteopenia. In patients with Cushing syndrome, the intravertebral fat content did not differ from that in the volunteers. Intravertebral fat does not correlate well with bone mineral content within any group and appears to be related to other factors.