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.