CLINICAL APPLICATION OF MAGNETIC RESONANCE IMAGING (MRI) FOR DIAGNOSIS OF ANGIOMYOLIPOMA

The purpose of this study was to evaluate the MRI in angiomyolipoma. MRI was performed in five cases of angiomyolipoma and compared with X-ray computed tomography. The MRI, Toshiba model MRT 15A with resistive magnet of 0.15 Tesla, was used and images were produced in transvers and coronal directions with different repetition times, delay times and echo times. The characteristic images associated with angiomyolipoma were demonstrated. Angiomyolipoma is a hamartoma that contains vascular, smooth muscle and mature fatty elements. Generally the attenuation values on X-ray CT scans are low and are one of the most important points for diagnosis of angiomyolipoma. Since the fat cells are normal in appearance and resemble the cells found in the retroperitoneal fat and subcutaneous fat, the NMR signal intensity from angiomyolipoma is very high on MRI using T1-weighted images; such as short SE image or IR image. Four of five cases of angiomyolipoma demonstrated this characteristic and actual T1 values of these cases are rather shorter than the parenchyma of the kidney. One case of angiomyolopoma can be followed by MRI without operation in one year. Magnetic resonance imaging appears to be an accurate way of detecting, identifying angiomyolipoma.