Radiology
All radiological measurements were performed by the same radiologist(MK). Perirenal fat thickness was measured at the level of the renal vein, from the posterior renal capsule to the posterior abdominal wall using CT images. These measurements from CT images are referred to as perirenal fat depth to eliminate confusion. The perirenal field Hounsfield unit(HU) and subcutaneous fat HU(at the level of the hilus) were recorded according to a circular region of interest measuring 1 cm in diameter, using a PACS workstation and pre-operative CT images.