Successful Intravascular Treatment of an Intraosseous Arteriovenous Fistula in Fibrous Dysplasia.

Fibrous dysplasia (FD) is a benign bone disease characterized by expansile lesions that typically stabilize with age. Rarely, FD can undergo malignant transformation, presenting with atypical, rapid growth and destruction of adjacent bone. Other potential causes of rapid FD expansion include secondary lesions, such as aneurysmal bone cysts. We describe a case of an aggressive occipital lesion that presented with pain associated with diplopia and tinnitus, raising concern for malignant transformation. A massive intraosseous arteriovenous fistula was identified giving rise to an anomalous vein coursing to the cavernous sinus with compression of the abducens nerve. The vascular anomaly was mapped and after embolization symptoms resolved; a biopsy with extensive genetic analyses excluded malignancy. The differential diagnosis for expanding FD lesions includes aggressive FD, malignant transformation, and secondary vascular anomalies. In cases when traditional radiographic and histologic assessments are nondescript, use of additional radiographic modalities and genetic analyses are required to make an accurate diagnosis and guide treatment. When vascular anomalies are suspected, detailed angiography with embolization is necessary to define and treat the lesion. However, to rule out malignant transformation, genetic screening is recommended.

Migration and differentiation of neural precursors derived from human embryonic stem cells in the rat brain.

Human embryonic stem (hES) cells provide a potentially unlimited cell source for regenerative medicine. Recently, differentiation strategies were developed to direct hES cells towards neural fates in vitro. However, the interaction of hES cell progeny with the adult brain environment remains unexplored. Here we report that hES cell-derived neural precursors differentiate into neurons, astrocytes and oligodendrocytes in the normal and lesioned brain of young adult rats and migrate extensively along white matter tracts. The differentiation and migration behavior of hES cell progeny was region specific. The hES cell-derived neural precursors integrated into the endogenous precursor pool in the subventricular zone, a site of persistent neurogenesis. Like adult neural stem cells, hES cell-derived precursors traveled along the rostral migratory stream to the olfactory bulb, where they contributed to neurogenesis. We found no evidence of cell fusion, suggesting that hES cell progeny are capable of responding appropriately to host cues in the subventricular zone.

Role of CT perfusion imaging in the diagnosis and treatment of vasospasm.

The current role of CT perfusion (CTP) imaging in the diagnosis and treatment of vasospasm in the setting of aneurysmal subarachnoid hemorrhage is discussed in this article, with specific attention directed towards defining the terminology of vasospasm and delayed cerebral ischemia. A commonly used CTP technique in clinical practice is described. A review of the literature regarding the usefulness of CTP for the diagnosis of vasospasm and its role in guiding treatment are discussed. Recent research advances in the utilization of CTP and associated ongoing challenges are also presented.

Work-in-progress toward incorporating patients' preferences in practice guidelines for imaging aneurysmal subarachnoid hemorrhage.

RATIONALE AND OBJECTIVES: Patient-centered care has become a primary focus in clinical practice. In developing practice guidelines for clinical care, the patients' perspective is an important component. MATERIALS AND METHODS: Patients' preferences are represented in a decision analytic model as quality-of-life weights for different health states associated with the aneurysmal subarachnoid hemorrhage population. The time-tradeoff method is used to obtain the individual patients' preferences, which are directly measured in quality-adjusted life years. An individualized care model is explained as a means of implementing a patient-centered approach into practice guidelines for clinical care. A method for calculating the expected value for societal benefit from improved decision making using an individualized care model is reviewed. RESULTS: We discuss our work-in-progress towards incorporating patients' preferences in a decision analytic model for aneurysmal subarachnoid hemorrhage patients. The main methodologic concerns for using patients' preferences in cost-effectiveness analyses for developing practice guidelines are discussed. CONCLUSION: Emphasis is placed on using patients' preferences and patient-centered outcome measures in cost-effectiveness analyses.