Improved CT fat detection in small kidney angiomyolipomas using thin sections and single voxel measurements.

OBJECTIVE AND METHODS: Seven echogenic renal masses < 1.0 cm in size were studied by CT to make the diagnosis of angiomyolipoma by identifying the presence of fat.

RESULTS: In four of six lesions, initial 5 mm section CT failed to detect fat, although repeat 3 and/or 1.5 mm section CT was successful in demonstrating fat. In one patient who underwent 3 and 1.5 mm section CT, attenuation values of four voxels were low enough to indicate the presence of fat only on the 1.5 mm sections.

CONCLUSION: Measuring single voxel values in the hypoattenuating areas on nonenhanced thin (3 or 1.5 mm) sections is essential for CT diagnosis of small (< 1.0 cm) renal angiomyolipomas.