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Objectives: To study the incompletely understood sympathoexcitatory pathway through the human brain stem, using a new method of three dimensional brain stem mapping on the basis of digitally postprocessed magnetic resonance imaging (MRI).Methods: 258 consecutive patients presenting with acute signs of brain stem ischaemia underwent biplane T2 and EPI diffusion weighted MRI, with slice orientation parallel and perpendicular to a transversal slice selection of the stereotactic anatomical atlas of Schaltenbrand and Wahren, 1977. The individual slices were digitally normalised and projected onto the appropriate slices of the anatomical atlas. For correlation analysis lesions were imported into a three dimensional model of the human brain stem.Results: 31 of the 258 patients had Horner's syndrome caused by acute brain stem ischaemia. Only four of the patients with Horner's syndrome had pontine infarctions, 12 had pontomedullary lesions, and 15 had medullary lesions. Correlation analysis showed significantly affected voxels in the dorsolateral medulla but not in the pons. A statistical comparison with infarct topology in patients with medullary lesions but without Horner's syndrome indicated that involvement of the medial and ventral part of affected voxels located in the ventrolateral medullary tegmentum was specific for Horner's syndrome.Conclusions: Based on this first in vivo topodiagnostic study, the central sympathoexcitatory pathway probably descends through the dorsal pons before converging on specific generators in the ventrolateral medullary tegmentum at a level below the IX and X nerve exits. [ABSTRACT FROM AUTHOR]

Zusammenfassung Ziel der Untersuchung war die Evaluierung der Anwendbarkeit, Sensitivität und möglichen prädiktiven Aussagekraft der diffusionsgewichteten Sequenzen der Magnetresonanztomographie ( DWI diffusion weighted imaging) bei Patienten mit akuten vertebrobasilären Infarkten. Zwischen 1997 und 2002 wurden prospektiv 268 konsekutive Patienten mit akuten, auf eine vertebrobasiläre Ischämie verdächtigen Symptomen rekrutiert. Die Patienten erhielten eine echoplanare (EPI) T2- und EPI-diffusionsgewichtete MRT innerhalb von 24 h nach Beginn der Symptomatik und hochauflösende MRT innerhalb von 7 Tagen, davon 121 Patienten zusätzliche CT-Bildgebung. Im DWI ließ sich ein akuter vertebrobasilärer Infarkt bei 71,0% der Patienten nachweisen. Die mittlere Dauer für die DWI-Untersuchung betrug mit 8 min nicht länger als für eine CCT. In DW-Sequenzen zeigten sich signifikant mehr akute Läsionen als im CT (28,0%), im hochauflösenden MRT jedoch nicht mehr als im DWI alleine. Bei 42 Patienten mit TIA oder PRIND zeigten sich im DWI bei 41,8% akute Diffusionsstörungen. Bei 63 Patienten mit der wahrscheinlichsten Diagnose vertebrobasiläre Ischämie war das DWI unauffällig. Eine Woche nach dem Ereignis zeigten 88,9% dieser Patienten eine vollständige Remission oder nur minimale Restsymptomatik. DWI ist damit ein sensitiver Indikator für akute Infarkte im Versorgungsgebiet des hinteren Kreislaufs. Der zeitliche Aufwand ist vergleichbar dem einer CT und ein unauffälliges DWI kann als Prädiktor eines guten klinischen Outcomes bei Patienten mit Ischämien im Hirnstamm und Zerebellum gewertet werden. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the sensitivity of multimodal electrophysiological brainstem testing in the diagnosis of clinically suspected reversible ischemic deficits of the brainstem compared with diffusion weighted MR imaging. We investigated 158 consecutive patients presenting with signs of acute brainstem dysfunction. Serial electrophysiological brainstem tests including masseter reflex, blink reflex, masseter inhibitory reflex, AEP, MEP, EOG and the oculoauricular phenomenon were applied. In 14 of the 158 patients neurological deficits resolved in less than 24 hours, which was suggestive of a transitory ischemic attack (TIA), 19 patients had brainstem signs for more than 24 hours but less than 1 week, suggestive of a reversible ischemic neurological deficit (RIND). Electrophysiological data indicated acute functional brainstem lesions in 54,5 % of patients with transient clinical brainstem impairment. Lesion detection rate was significantly higher when combining electrophysiological data and MRI (60,4 %) than using acute brainstem abnormalities in diffusion weighted MRI alone (39,4 %). We conclude that diffusion weighted MRI and electrophysiological brainstem testing are complimentary sensitive indicators of acute brainstem lesions in patients with reversible neurological deficits. Correct identification of brainstem ischemia influences the therapeutic regimen and may improve patient outcome. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the sensitivity of diffusion weighted magnetic resonance imaging (MRI) for the diagnosis of clinically suspected reversible ischaemic deficits of the brainstem.Methods: A total of 158 consecutive patients presenting with acute signs of brainstem dysfunction were investigated using EPI diffusion weighted MRI within 24 hours of the onset of symptoms. High resolution T1 and T2 weighted imaging was performed as a follow up after a median of six days.Results: Fourteen of the 158 patients had a complete clinical recovery within 24 hours (transitory ischaemic attack (TIA)), and 19 patients recovered in less than one week (prolonged reversible neurological deficit (RIND)). Diffusion weighted MRI showed acute ischaemic deficits in 39% of patients with transient neurological deficits. The detection rate seemed to be higher in patients with longer lasting symptoms, but the difference between patients with TIA (29%) and RIND (47%) was not significant.Conclusions: Diffusion weighted MRI is a sensitive indicator of acute ischaemic brainstem deficits even in patients with reversible neurological deficit. Early identification of patients with TIA and increased risk of stroke may influence acute management and improve patient outcome. [ABSTRACT FROM AUTHOR]

We investigated the reliability of a new digital post-processing magnetic resonance imaging (MRI) technique in ischemic brain stem lesions to identify relations of the lesion to anatomical brain stem structures. The target was a medial longitudinal fasciculus (MLF) lesion, which was evident from ipsilateral internuclear ophthalmoplegia (INO). Sixteen patients with acute unilateral INO and an isolated acute brain stem lesion in T2- and EPI-diffusion weighted MRI within 2 days after the onset of symptoms were studied. The MRI slice direction was parallel and perpendicular to a slice selection of a stereotactic anatomical atlas. The individual slices were normalized and projected in the digitalized atlas. The eye movement disorder was monitored by electro-oculography. In all patients with clinical or subclinical electro-oculographically documented INO and MRI proven brain stem infarction the lesion covered or at least partially overlapped the ipsilateral MLF at one or more atlas levels. We conclude that digital post-processing MRI with normalizing and projecting brain stem lesions in an anatomical atlas is a reliable method to demonstrate the anatomical structures involved by the lesion. Combined with electrophysiological brain stem testing, this method may be a useful tool to identify incompletely understood pathways mediating brain stem reflexes or the generators of evoked potentials. [ABSTRACT FROM AUTHOR]