Peripheral nerve involvement in multiple sclerosis: Demonstration by magnetic resonance neurography.

OBJECTIVE: To detect and quantify peripheral nerve lesions in multiple sclerosis (MS) by magnetic resonance neurography (MRN). METHODS: Thirty-six patients diagnosed with MS based on the 2010 McDonald criteria (34 with the relapsing-remitting form, 2 with clinically isolated syndrome) with and without disease-modifying treatment were compared to 35 healthy age-/sex-matched volunteers. All patients underwent detailed neurological and electrophysiological examinations. Three Tesla MRN with large anatomical coverage of both legs and the lumbosacral plexus was performed by using 2-dimensional (2D) fat-saturated, T2-weighted (T2w) and dual echo turbo spin echo sequences as well as a 3D T2-weighted, fat-saturated SPACE sequence. Besides qualitative visual nerve assessment, a T2w signal quantification was performed by calculation of proton spin density and T2 relaxation time. Nerve diameter was measured as a morphometric criterion. RESULTS: T2w hyperintense nerve lesions were detectable in all MS patients, with a mean lesion number at thigh level of 151.5 ± 5.7 versus 19.1 ± 2.4 in controls (p < 0.0001). Nerve proton spin density was higher in MS (tibial/peroneal: 371.8 ± 7.7/368.9 ± 8.2) versus controls (tibial/peroneal: 266.0 ± 11.0/276.8 ± 9.7, p < 0.0001). In contrast, T2 relaxation time was significantly higher in controls (tibial/peroneal: 82.0 ± 2.1/78.3 ± 1.7) versus MS (tibial/peroneal: 64.3 ± 1.0/61.2 ± 0.9, p < 0.0001). Proximal tibial and peroneal nerve caliber was higher in MS (tibial: 52.4 ± 2.1mm2 , peroneal: 25.4 ± 1.3mm2 ) versus controls (tibial: 45.2 ± 1.4mm2 , p < 0.0015; peroneal: 21.3 ± 0.7mm2 , p = 0.0049). INTERPRETATION: Peripheral nerve lesions could be visualized and quantified in MS in vivo by high-resolution MRN. Lesions are defined by an increase of proton spin density and a decrease of T2 relaxation time, indicating changes in the microstructural organization of the extracellular matrix in peripheral nerve tissue in MS. By showing involvement of the peripheral nervous system in MS, this proof-of-concept study may offer new insights into the pathophysiology and treatment of MS. Ann Neurol 2017;82:676-685.

Transradial access or Simmons shaped 8F guide enables delivery of flow diverters in patients with large intracranial aneurysms and type III aortic arch: technical case report.

BACKGROUND AND IMPORTANCE: Flow diversion with the pipeline embolization device (PED) is an emerging endovascular technology allowing curative embolization of very large and giant intracranial aneurysms. Many patients with these complex aneurysms are older. The presence of a tortuous type III aortic arch reduces the chances of successful PED delivery and increases the risk of complications. We report 2 technical nuances regarding the delivery of the PED in older patients with a complex aortic arch. CLINICAL PRESENTATION: In case 1, an 87-year-old woman presented with acute-onset left third nerve palsy. Workup demonstrated an 18-mm left posterior carotid wall aneurysm with a large daughter aneurysm on its dome. Endovascular access was complicated by a type III aortic arch with a hyperacute angle at the origin of the left common carotid artery. An 8F Simmons II shaped guide formed a stable platform, allowing successful PED delivery. In case 2, a 76-year-old woman experienced a transient ischemic attack. She harbored a right-sided 20-mm cavernous internal carotid artery aneurysm. She was treated with 2 PEDs deployed via a transradial approach. CONCLUSION: Transradial access or guide support with the 8F Simmons II catheter grants stable access for curative embolization with the PED in elderly patients with a large intracranial aneurysm and a complex aortic arch.