Lumbosacral plexus and pudendal nerve magnetic resonance tractography: A systematic review of the clinical applications for pudendal neuralgia.

Diffusion tensor imaging (DTI) is commonly used to establish three-dimensional mapping of white-matter bundles in the supraspinal central nervous system. DTI has also been the subject of many studies on cranial and peripheral nerves. This non-invasive imaging technique enables virtual dissection of nerves in vivo and provides specific measurements of microstructural integrity. Adverse effects on the lumbosacral plexus may be traumatic, compressive, tumoral, or malformative and thus require dedicated treatment. DTI could lead to new perspectives in pudendal neuralgia diagnosis and management. We performed a systematic review of all articles or posters reporting results and protocols for lumbosacral plexus mapping using the DTI technique between January 2011 and December 2023. Twenty-nine articles published were included. Ten studies with a total of 351 participants were able to track the lumbosacral plexus in a physiological context and 19 studies with a total of 402 subjects tracked lumbosacral plexus in a pathological context. Tractography was performed on a 1.5T or 3T MRI system. DTI applied to the lumbosacral plexus and pudendal nerve is feasible but no microstructural normative value has been proposed for the pudendal nerve. The most frequently tracking parameters used in our review are: 3T MRI, b-value of 800 s/mm2, 33 directions, 3 × 3 × 3 mm3, AF threshold of 0.1, minimum fiber length of 10 mm, bending angle of 30°, and 3DT2 TSE anatomical resolution. Increased use of DTI could lead to new perspectives in the management of pudendal neuralgia due to entrapment syndrome, whether at the diagnostic, prognostic, or preoperative planning level. Prospective studies of healthy subjects and patients with the optimal acquisition parameters described above are needed to establish the accuracy of MR tractography for diagnosing pudendal neuralgia and other intrapelvic nerve entrapments.

[Antibodies against hepatitis B virus core antigen among blood donors]. / Anticorps dirigés contre l'antigène de core du virus de l'hépatite B chez les donneurs de sang.

The prevalence of antibodies to the hepatitis B virus (HBV) core antigen (anti-HBc) and the risk factors are evaluated in different blood donor groups. In 1998, on 12,456 first donations, 163 (1.31%) were positive with the two anti-HBc screening tests. Samples were from 69 women (42.3%) and 94 men (57.7%). Three subjects had no anti-HBs but were anti-HBc IgM negative. Forty (24.5%) donors were born in another country than France, and the majority (25 donors, 62.5%) were from North Africa. HBV vaccine had been previously given in 14 subjects (8.6%). Eight (4.9%) had hepatitis before the first donation. Trips in endemic areas (Africa and Asia) were taken by 26 subjects out of 76 donors with follow-up. Two (2.6%) had been previously transfused and six (7.9%) had contact with HBV-infected people. Among 78,033 repeat donations, 26 were positive with the two Anti-HBc screening tests (0.033%). Sixteen were negative after a second test and were probably false positive. Among the ten last donors, nine were Anti-HBs positive. One had anti-HBc IgM and had been recently infected by HBV. The prevalence of Anti-HBc in first-donation persons remains low. Trips in endemic areas and contact with an HBV-infected subject are the most frequent risk factors. Lastly, HBV seroconversion in repeat blood donors is a rare event. Anti-HBc screening in transfusion remains limited.