The incremental value of histogram analysis in the differentiation between hyperdense cysts and solid renal masses on unenhanced CT images.

The article investigates the utility of voxel histogram analysis (HA) in differentiating hyperdense renal cysts from small solid malignant renal masses on unenhanced CT scans. In a retrospective study of 99 hyperdense cystic lesions and 28 solid malignant lesions, HA using the 75th and 90th percentiles of voxel attenuation values demonstrated significantly higher diagnostic accuracy (77.2% and 68.5%, respectively) compared to the conventional mean attenuation threshold of 70 Hounsfield Units (HU) (37.0%). Most lesions exhibited a Gaussian distribution of voxel attenuation, allowing percentile calculations from a single region of interest (ROI) measurement. The findings suggest that HA, particularly using a 75th percentile cutoff of 65 HU, could improve sensitivity in characterizing hyperdense cysts without compromising specificity, though external multi-institutional validation is needed.