Hippocampal calcification prevalence at CT: a retrospective review.

PURPOSE: To determine the prevalence of intrahippocampal calcification at brain computed tomography (CT), evaluate any association with calcification involving the intracranial arteries or lentiform nuclei, and assess the clinical importance of intrahippocampal calcification. MATERIALS AND METHODS: Study approval was obtained by the Southern Health Human Research Ethics Committee, which waived the requirement for informed consent because of the retrospective nature of the study. The presence of intrahippocampal calcification was assessed by four readers through retrospective review of 300 randomly selected nonenhanced brain CT scans. In addition, the presence of calcification involving the intracranial arteries and lentiform nuclei was assessed, and the clinical histories were reviewed in those patients with intrahippocampal calcifications and a matched control cohort without intrahippocampal calcification. Differences in proportion of patients with intrahippocampal calcifications across different age groups were assessed by using χ2 analysis. Interrater agreement and intrarater agreement were assessed by using κ analysis. RESULTS: Intrahippocampal calcification was demonstrated in 47 (15.7%) of 300 patients, and 47 (21.7%) of 217 patients older than 50 years of age. Its prevalence increased with age (P=.008). All patients with intrahippocampal calcification and the control cohort demonstrated calcification involving the intracranial arteries. Eleven (23.4%) of 47 patients with intrahippocampal calcification had calcification within the lentiform nuclei compared with 14 (29.8%) of 47 in the control cohort (P=.67). The anatomic distribution of intrahippocampal calcification was similar to that described in vascular fibrosis and calcification. CONCLUSION: The prevalence of intrahippocampal calcification appears to increase with age and is a relatively common finding in patients older than 50 years. It has a similar anatomic distribution to microscopic vascular fibrosis and calcification and likely reflects its latter stages.

MR imaging of meniscal and cartilage injuries of the knee.

This article addresses the role of MR imaging in the evaluation of meniscal injuries, with emphasis placed on the common meniscal injuries, including horizontal, longitudinal, radial, and flap tears. An understanding of typical meniscal postoperative findings, together with those factors responsible for the misinterpretation of meniscal abnormalities, is essential for the accurate assessment of MR imaging in the athlete. This article also reviews the common articular cartilage injuries identified in the knee. MR imaging is the imaging modality of choice for the assessment of the menisci and articular cartilage, with the ready availability of MR imaging allowing for the rapid assessment of the injured athlete.

CT-demonstrated transcalvarial channels diagnostic of dural arteriovenous fistula.

MR imaging-evident intraosseous channels associated with the presence of a dural arteriovenous fistula have been described in the literature. We describe these channels in relation to a case of dural arteriovenous fistula seen on CT. The presence of this subtle sign should be sought, and the area reviewed in all CT evaluations of patients with pulsatile tinnitus.

Gliosarcoma with osteosarcomatous differentiation: review of radiological and pathological features.

Gliosarcoma is a rare tumor of the central nervous system, consisting of gliomatous and sarcomatous elements. We present an unusual case of gliosarcoma which demonstrated a variation in phenotype over a six month period, changing from a gliosarcoma with osteosarcomatous differentiation, to a gliosarcoma with no osteosarcomatous component. The initial histological diagnosis was glioblastoma multiforme. Fifteen months later the tumor had transformed into a gliosarcoma demonstrating osteosarcomatous differentiation, with the majority of the tumor consisting of osteoid matrix. Further samples taken six months later revealed gliosarcoma with almost no osteosarcomatous component. It is recognized that glioblastoma can undergo a change in phenotype, transforming into a gliosarcoma. This case demonstrates that ongoing changes in phenotype can occur, especially when the tumor has been treated with chemotherapy and radiotherapy. An understanding of the pathological progression of gliosarcoma will become increasingly important as novel treatments for gliosarcoma and glioblastoma become available.