Michael Knauth MD, PhD, Presenter: Nothing to Disclose

Kai Kallenberg MD, Abstract Co-Author: Nothing to Disclose

Christoph Dehnert MD, Abstract Co-Author: Nothing to Disclose

Arnd R. Doerfler MD, Abstract Co-Author: Nothing to Disclose

Damian Miles Bailey PhD, Abstract Co-Author: Nothing to Disclose

Peter Bartsch MD, Abstract Co-Author: Nothing to Disclose

In post-mortem exams multiple micro-hemorrhages were found in the brain of HACE victims, suggesting a disruption of the blood brain barrier (BBB) in lethal HACE .We hypothesized that micro-hemorrhages may also occur in severe non-lethal HACE and that therefore accumulation of hemosiderin indicative of micro-hemorrhage can be found in HACE survivors. Subjects with severe AMS (acute mountain sickness) were to serve as controls.

In 3 individuals with HACE within the past 3 years a brain MRI with a focus on micro-hemorrhages was performed. Three individuals with comparable altitude exposure who had developed AMS but without signs of HACE served as controls. MRI protocol consisted of  T2w, T2* and SW (susceptibility weighted) images. MRI was performed with a clinical 3-Tesla scanner. Scans were independently evaluated by two neuroradiologists blinded to the medical history and clinical data.  

T2w images revealed microbleeds only in the most severely affected HACE subject. T2* showed blood remnants in the corpus callosum (CC) in all 3 HACE-subjects whereas the control (AMS) subjects were not affected. Additionally, in one HACE subject there were post-hemorrhagic lesions in the white matter of the frontal, parietal and occipital lobes and in the insular region. The SWI data confirmed the results of the T2*w with the exception that more micro-hemorrhages in additional localizations were detected and their delineation was clearer.

The new finding of this study is that hemoglobin degradation products are detectable in the brain of HACE survivors whereas cerebral microhemorrhages were not detected in individuals with comparable altitude exposure who only suffered from severe AMS. Our observations are consistent with vasogenic edema previously documented in HACE (Hackett et al. 1998). The disruption of the BBB and micro-hemorrhages in the CC may be a distinct morphologic characteristic that distinguishes HACE from AMS. The micro-hemorrhages in HACE remain detectable over several years. Thus these microbleeds in the CC may prove to be a novel diagnostic feature of HACE and provide an exciting opportunity for retrospective diagnosis.

Microhemorrhages in the corpus callosum may be a distinct morphologic characteristic distinguishing HACE from AMS. This may provide an exciting new opportunity for retrospective (MR)diagnosis of HACE.

Knauth, M, Kallenberg, K, Dehnert, C, Doerfler, A, Bailey, D, Bartsch, P, Microhemorrhages in the Splenium of the Corpus Callosum (CC) Are a New MRI Sign of High Altitude Cerebral Edema (HACE).  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6006703.html