Methodik und was kann die MR-Neurografie?

Zusammenfassung

Die MR-Neurografie kann in vielen Fällen durch die Möglichkeit der direkten, visualisierenden Läsionslokalisation und der Bestimmung räumlicher Läsionsmuster den klinisch-elektrophysiologischen Befund sinnvoll ergänzen und nicht selten therapierelevante zusätzliche Befunde erheben. Die sehr genaue Lokalisationsdiagnostik kann mit der MR-Neurografie auch an Stellen erfolgen, die der elektrophysiologischen, neurosonografischden oder bioptischen Untersuchung nicht oder nur sehr schwer zugänglich sind (bspw. proximale Extremitäten oder Plexusregionen). Der bildgebende Kontrast von Nervenläsionen, auch bei nicht traumatischen, intrinsischen Neuropathien und Polyneuropathien ist in der MR-Neurografie in der Regel stark und deutlich (im T2w oder PDw Bild) und es gibt erste Hinweis dass dieser Läsionskontrast (hyperintense Nervenfaszikelläsion) dem sonografischen Nervenläsionskontrast überlegen ist. Neben der reinen Lokalisationsdiagnostik können bereits mit erweiterten Verfahren der MR-Neurografie mikrostrukturelle und pathophysiologische Informationen zur Faserdichte, Myelinisierung, Nervendurchblutung und auch Schrankenstörungen zw. Nerven-Blut-Gewebeschranke nicht-invasiv detektiert und quantifiziert werden.

Abstract

In many clinical situations where patients are suspected to suffer from peripheral neuropathy MR neurography can aid in improving diagnostic decisions by precisely determining lesion localisation and spatial patterns of lesion dispersion. Even in anatomic regions difficult to be examined by NCS/EMG, sonography or impossible to be sampled by obtaining biopsy specimens, such as the proximal extremities or plexus regions, MR neurography can accurately determine and localise nerve lesions not only in extrinsic, mechanically induced or traumatic neuropathies but also in the large group of intrinsic spontaneously occurring neuropathies and polyneuropathies. The nerve lesion contrast on MR neurography images in symptomatic patients typically is strong and unambiguous (in T2w or PDw images) and first reports indicate that nerve fascicle lesion contrast of MR neurography is superior to the lesser hypoechogenic contrast of nerve high-resolution ultrasonography. In addition to spatial lesion determination and localisation, MR neurography offers techniques giving quantitative insight into pathological alterations of nerve microstructure and pathophysiology such as axon density, integrity of myelinisation, nerve perfusion and disturbances of the nerve-blood barrier.

Schlüsselwörter

periphere Nervensystem - MRT - MR-Neurografie - periphere Neuropathien - klinischen Neurophysiologie - neurographischen Untersuchungen - Läsionslokalisation

Key words

peripheral nervous system - MRI - MR neurography - peripheral neuropathy - clinical neurophysiology - nerve conduction studies - lesion localisation

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