Vessel Wall MRI for Targeting Biopsies of Intracranial Vasculitis.

Central nervous system vasculitides are elusive diseases that are challenging to diagnose because brain biopsies have high false-negative rates. We sought to test the ability of contrast-enhanced, high-resolution 3D vessel wall MR imaging to identify vascular inflammation and direct open biopsies of intracranial target vessels and adjacent brain parenchyma. Eight of 9 specimens revealed vascular inflammation. We conclude that vessel wall MR imaging can identify inflamed intracranial vessels, enabling precise localization of biopsy targets.

Carotid plaque neovascularization and hemorrhage detected by MR imaging are associated with recent cerebrovascular ischemic events.

BACKGROUND AND PURPOSE: Pathologic studies suggest that neovascularization and hemorrhage are important features of plaque vulnerability for disruption. Our aim was to determine the associations of these features in carotid plaques with previous cerebrovascular ischemic events by using high-resolution CE-MRI. MATERIALS AND METHODS: Forty-seven patients (36 men; mean age 72.5 ± 10 years) underwent CE-MRI and MRA examinations for carotid plaque at 3T. IPH presence was recorded. Neovascularity was categorized by the degree of adventitial enhancement (0, absent; 1, <50%; 2, ≥50%). Reader variability was assessed by using weighted κ. Associations with events were determined by using multivariable logistic regression. RESULTS: Intra- and inter-reader agreement for grading adventitial enhancement were good to excellent. IPH was present in 49% of patients and was associated with events (P = .03). Patients grouped by categories 0, 1, and 2 adventitial enhancement had increasing frequencies of events (14% category 0, 48% category 1, 65% category 2; P = .02). Events were associated with IPH (OR, 10.18; 95% CI, 1.42-72.21) and adventitial enhancement (compared with category 0: OR, 14.90, 95% CI, 0.98-225.93 for category 1; OR, 51.17, 95% CI, 3.4-469.8 for category 2) after controlling for age, sex, cardiovascular risk factors, wall thickness, and stenosis. Stenosis was not associated with events. CONCLUSIONS: Adventitial enhancement and IPH are independently associated with previous events and may provide important insight into stroke risk not achievable by stenosis.

Patterned expression of BDNF and NT-3 in the retina and anterior segment of the developing mammalian eye.

PURPOSE: The neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) are hypothesized to play an important role in vertebrate eye development because of their patterned expression in the developing and adult neuroretina, their regulated response to retinal and optic nerve injury, and the effects of altered neurotrophin signaling on retinal development. To further characterize the role of these neurotrophins in mammalian eye development and maintenance, the pattern of expression of BDNF and NT-3 was analyzed in the developing and mature mouse eye. METHODS: Using mouse strains in which the reporter gene lacZ, encoding the enzyme beta-galactosidase, was targeted to either the BDNF or NT-3 locus, the expression of BDNF and NT-3 in the eyes of mice heterozygous for these mutations was analyzed by enzyme histochemistry during embryogenesis, postnatal development, and adulthood. RESULTS: BDNF and NT-3 expression were first observed in the inner and outer segments of the developing optic cup at embryonic days 10.5 to 11.5. As the retina matured, BDNF expression was restricted to retinal ganglion cells and a subset of cells in the inner nuclear layer (INL), whereas NT-3 expression was confined to a small subset of cells in the INL and ganglion cell layer. Both neurotrophins were expressed within the developing retinal pigment epithelium. In the anterior segment, BDNF and NT-3 were expressed at high levels in the developing and mature ciliary epithelium. In the lens and cornea, however, these neurotrophins displayed distinct patterns of expression during development and adulthood. BDNF expression was found in the lens epithelium, immature trabecular meshwork, corneal endothelium, and corneal epithelium, whereas NT-3 expression was confined to the corneal epithelium. CONCLUSIONS: BDNF and NT-3 exhibit different, yet overlapping, patterns of expression during the development and differentiation of the mouse eye. In addition to the neuroretina, the spatiotemporal expression of BDNF and NT-3 may play an important role in the development and maintenance of the lens, ciliary body, trabecular meshwork, and cornea.