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Figure 4. A 54-year-old female with hepatitis C cirrhosis presenting with an LR 5 observation in segment 2 of the liver on arterial phase contrast-enhanced CT (A). After a multidisciplinary discussion, the patient was treated with TACE. CT performed 1 month post TACE shows partial necrosis of the tumor with residual mass-like nodular enhancement along the margin of the lesion, LR-TR Viable (B). The patient was again presented at a multidisciplinary liver tumor board, and the decision was made for SBRT. Arterial phase MRI 3 months post SBRT reveals a decrease in the size of the targeted lesion with residual linear areas of intralesional enhancement, LR-TR Nonprogressing (C). Note that since SBRT was performed after TACE, the post-treatment imaging findings after radiation should dominate treatment response assessment. Therefore, the presence of mass-like intralesional enhancement, although a small septation, with decreasing size, is considered LR-TR Nonprogressing. Arterial phase MRI 6 months post SBRT shows an increasing area of intralesional enhancement (D). Because this was not mass-like or nodular, the reader believed it was "Equivocal"; however, since Equivocal is no longer terminology for radiation-treated HCC, LR-TR Nonprogressing category should be given instead. Arterial phase MRI performed 12 months post SBRT (E) demonstrates increasing size of mass-like enhancement along the margin of the treated lesion, LR-TR Viable. The patient was presented at a multidisciplinary liver tumor board again, with the decision for repeat SBRT. Arterial phase CT 3-, 6-, and 12 months (F, G, and H, receptively) post repeat SBRT demonstrates no intralesional enhancement, LR-TR Nonviable. Note the surrounding parenchymal enhancement from the nontarget effects of radiation. Over time, there is progressive atrophy of the left lobe of the liver secondary to radiation fibrosis.