The evaluation of tumor response after systemic and locoregional therapies is essential in directing management for HCC. An understanding of the various therapeutic strategies and of their posttherapy imaging appearances is essential for accurately assessing treatment response. The evaluation of tumor response should include not only anatomic imaging biomarkers, such as reduction in tumor size, but also tumor enhancement and necrosis.

We report the case of a 35 year old African American female who developed hypertrophic olivary degeneration secondary to resection of a pontine cavernous malformation. The patient initially complained of headaches and diplopia. Unenhanced computed tomography (CT) and magnetic resonance images (MRI) of the brain revealed a left pontine cavernous malformation with scattered foci of recent and remote hemorrhage. The patient subsequently underwent surgical resection of the lesion. Follow up MRI 7 months post surgery demonstrated hypertrophy and T2 signal hyperintensity in the ipsilateral inferior olivary nucleus secondary to hypertrophic olivary degeneration. Familiarity with this diagnosis and its imaging characteristics is required of the radiologist to prevent erroneous diagnoses of other pathology.

In order to examine the accuracy of magnetic resonance imaging (MRI)-based diagnosis of neuromyelitis optica (NMO) versus multiple sclerosis (MS), we performed a retrospective, rater-blinded review of 29 cases of NMO and 30 cases of MS using the criteria of long (more than three vertebral levels), continuous lesions with a central cord location for NMO and more peripheral and patchy lesions for MS. Using these criteria, two raters were able to distinguish the two conditions with a good degree of confidence, particularly when the imaging was performed at the time of an acute cord attack. The sensitivity and specificity for diagnosis of NMO were 86.2% and 93.3%, respectively, for Rater A and 96.4% and 78.6%, respectively, for Rater B, with a kappa value of 0.72. Thus there are significant differences in lesion characteristics that allow the distinction on spinal cord imaging between MS and NMO with a moderately high degree of confidence. The location of the lesion as evident on MRI of the spine can be regarded as a distinguishing diagnostic feature between MS and NMO.

Dermatofibrosarcoma protuberans is a rare locally aggressive cutaneous tumor of intermediate malignancy. It is a slow-growing neoplasm with a marked propensity to recur after resection. Head and neck involvement is unusual and distant metastases are quite rare but tend to be more frequent in tumors that undergo fibrosarcomatous degeneration. We present the imaging and corresponding histopathology in a case of dermatofibrosarcoma protuberans of the scalp demonstrating fibrosarcomatous degeneration and lung metastasis.

Perfusion-computed tomography can successfully be used to define cerebral ischemia and infarction within the posterior fossa and aid in decisions to proceed with neurointervention.