Arteriography Kidney Cross-sectional imaging has replaced arteriography for the evaluation of indeterminate renal masses. There is no relevant literature regarding the use of arteriography in the evaluation of indeterminate renal masses. CT Abdomen Iodinated CT contrast is contraindicated in some patients with severe allergy to the CT contrast or in patients who are at high risk for contrast-induced nephropathy. For more details, please refer to the ACR Manual on Contrast Media [71]. The inability to utilize IV contrast to evaluate a renal mass markedly limits whether it can be classified as benign or malignant on CT, but it can provide some information. Homogenous renal masses measuring <20 HU or >70 HU [1,2] or lesions containing macroscopic fat can be characterized as benign lesions, but all other small lesions cannot be characterized using CT without IV contrast. Large lesions with calcifications and necrosis may not need further characterization, but detection of venous invasion and metastases is also limited. CTU There is no relevant literature regarding the use of CTU in the evaluation of indeterminate renal masses. Indeterminate Renal Mass Ho et al [51] showed that the optimal percentage of enhancement threshold for distinguishing cysts from solid tumors on MRI was 15%. Hecht et al [52] reported that both quantitative and qualitative methods are sensitive in the detection of enhancement in a renal lesion on MRI and that subtracted images enables accurate assessment of tumor enhancement for intrinsically hyperintense lesions using qualitative methods. Although MRI without and with IV contrast is optimal for renal lesion characterization, MRI without IV contrast can also provide diagnostic information. For example, simple cystic lesions or even those with thin septations can often be characterized on noncontrast T2-weighted imaging based on their homogeneous and very high T2 signal intensity.
Indeterminate Renal Mass. Arteriography Kidney Cross-sectional imaging has replaced arteriography for the evaluation of indeterminate renal masses. There is no relevant literature regarding the use of arteriography in the evaluation of indeterminate renal masses. CT Abdomen Iodinated CT contrast is contraindicated in some patients with severe allergy to the CT contrast or in patients who are at high risk for contrast-induced nephropathy. For more details, please refer to the ACR Manual on Contrast Media [71]. The inability to utilize IV contrast to evaluate a renal mass markedly limits whether it can be classified as benign or malignant on CT, but it can provide some information. Homogenous renal masses measuring <20 HU or >70 HU [1,2] or lesions containing macroscopic fat can be characterized as benign lesions, but all other small lesions cannot be characterized using CT without IV contrast. Large lesions with calcifications and necrosis may not need further characterization, but detection of venous invasion and metastases is also limited. CTU There is no relevant literature regarding the use of CTU in the evaluation of indeterminate renal masses. Indeterminate Renal Mass Ho et al [51] showed that the optimal percentage of enhancement threshold for distinguishing cysts from solid tumors on MRI was 15%. Hecht et al [52] reported that both quantitative and qualitative methods are sensitive in the detection of enhancement in a renal lesion on MRI and that subtracted images enables accurate assessment of tumor enhancement for intrinsically hyperintense lesions using qualitative methods. Although MRI without and with IV contrast is optimal for renal lesion characterization, MRI without IV contrast can also provide diagnostic information. For example, simple cystic lesions or even those with thin septations can often be characterized on noncontrast T2-weighted imaging based on their homogeneous and very high T2 signal intensity.