Renal angiomyolipoma: comparison of MRI and CT results for diagnosis

The aim of this study was to compare the potentials of MRI and CT for characterising renal angiomyolipomas. MRI and CT examinations of 13 adult patients with renal angiomyolipoma were reviewed. Pathological correlation was available for ten patients who underwent nephrectomy or tumourectomy. Negative CT density numbers were demonstrated in 10 cases. MRI depicted high signal intensity areas suggesting fat in 11 cases. A haemorrhagic component was suggested by both CT and MRI in 4 cases and was confirmed by surgery. Fat suppression imaging was performed in 3 cases and confirmed the presence of fat. We conclude that identification of angiomyolipomas can be achieved by MRI, but compared with CT, MRI is more expensive and less available. Therefore MRI should be performed when CT results are equivocal and when direct multiplanar images are necessary for a precise tumour localisation of multiple angiomyolipomas. (orig.)