Intracranial vessel wall magnetic resonance imaging features of infectious vasculitis.

Vasculitis is a complication of several infectious diseases affecting the central nervous system, which may result in ischemic and/or hemorrhagic stroke, transient ischemic attack, and aneurysm formation. The infectious agent may directly infect the endothelium, causing vasculitis, or indirectly affect the vessel wall through an immunological mechanism. The clinical manifestations of these complications usually overlap with those of non-infectious vascular diseases, making diagnosis challenging. Intracranial vessel wall magnetic resonance imaging (VWI) enables the evaluation of the vessel wall and the diseases that affect it, providing diagnostic data beyond luminal changes and enabling the identification of inflammatory changes in cerebral vasculitis. This technique demonstrates concentric vessel wall thickening and gadolinium enhancement, associated or not with adjacent brain parenchymal enhancement, in patients with vasculitis of any origin. It permits the detection of early alterations, even before a stenosis occurs. In this article, we review the intracranial vessel wall imaging features of infectious vasculitis of bacterial, viral, and fungal etiologies.

Magnetic resonance imaging of the fetal brain at 3 Tesla: Preliminary experience from a single series.

To report our preliminary experience with cerebral fetal magnetic resonance imaging (MRI) with a 3 Tesla (3T) scanner. We assessed feasibility, time of acquisition, and possibility to establish a diagnosis.Fifty-nine pregnant women had fetal MRI performed during the third trimester of pregnancy due to clinical or sonography concern of a central nervous system anomaly. No fetal or maternal sedation was used. The MRI protocol consisted of T2 turbo-spin-echo images in 3 planes of space. No T1-weighted images were performed. All images were analyzed by 2 pediatric neuroradiologists, who evaluated spatial resolution, artifacts, time of acquisition, and possibility to establish a diagnosis suspected by sonography.Examinations were performed safely for all patients. The images required longer time of acquisition (approximately 75 seconds for each plane in the space). The specific absorption rate was not exceeded in any fetus. Cerebral fetal MRI was normal in 22 cases. The spectrum of diagnostics included isolated ventriculomegaly, posterior fossa malformation, corpus callosum malformation, gyration anomalies, craniosynostosis, tuberous sclerosis, microcephaly, external hydrocephaly, midline arachnoid cyst, cerebral lesions, and persistent hyperplastic primitive vitreous.In our series, 3 T MRI of fetal brain was feasible and able to establish a diagnosis but required longer time of acquisition.

Discovery of human immunodeficiency virus infection by immunohistochemistry on lymph node biopsies from patients with unexplained follicular hyperplasia.

Over the last 10 years, 240 cases of hyperplasic lymphadenitis have been systematically tested in our institution for the presence of the human immunodeficiency virus (HIV). This series comprised patients between 15 and 90 years (median of age: 38.51) without a past history of HIV infection. The technical approach consisted in an immunohistochemical procedure with a monoclonal antibody against the p24-gag protein of HIV. Among the 240 cases, 105 had a true follicular hyperplasia. Overall, this survey found that 4 cases (3 males and 1 female) were positive for p24-gag without previous knowledge of HIV infection (4/240=1.66%). HIV infection was further confirmed by serologic and molecular investigations in all cases. These results were seen exclusively in those cases with prominent follicular hyperplasia (4/105=3.80%). Staining with the anti-p24 antibody was intense and restricted to the follicular dendritic cell networks. In one case, beside hyperplasic germinal centers, one could see a regressed onion bulblike structure. One important conclusion can be drawn from this study. A systematic research of HIV proteins should be performed in all lymph node biopsies with marked follicular hyperplasia, in a context of polyadenopathy, fever, and general status alteration. Besides giving an accurate diagnosis, this approach may be helpful in cases of recent infection in which anti-p24 antibodies are not yet detectable in the serum.