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J Neurosci Res. 2010 Feb 1. [Epub ahead of print]
Reinterpreting the magnetic resonance signs of hemodynamic impairment in the brains of multiple sclerosis patients from the perspective of a recent discovery of outflow block in the extracranial veins.
Simka M, Zaniewski M.

Private Healthcare Institution SANA, Department of Angiology, Pszczyna, Poland.

Multiple sclerosis patients examined with perfusion magnetic resonance (MR) imaging techniques have been found to have patterns of abnormal blood flow. These include prolonged mean transit time, a trend toward decreased cerebral blood flow in the area of plaques, and decreased cerebral blood flow and prolonged mean transit time within normal-appearing white matter. Increased cerebral blood flow and volume and decreased mean transit time (compared with the baseline values before the relapse) were found to precede the development of plaques. In addition, susceptibility-weighted imaging utilizing deoxyhemoglobin as the contrast has revealed that venous blood in cerebral veins of multiple sclerosis patients is less deoxygenated compared with healthy controls. All these findings were traditionally interpreted as a sign of local flow disturbances mediated by inflammatory and neurodegenerative processes. However, recent findings of significant stenoses in the extracranial veins that drain the brain and spinal cord shed new light on these MR results. With the assumption that a majority, if not all, of multiple sclerosis patients exhibit such extracranial venous obstacles, the perfusion MR images of multiple sclerosis patients should be reinterpreted. Perhaps ongoing MR studies with respect to extracranial venous hemodynamics may decipher some of the unsolved puzzles related to this neurologic disease. (c) 2010 Wiley-Liss, Inc.

With the assumption that a majority, if not all, of multiple sclerosis patients exhibit such extracranial venous obstacles, the perfusion MR images of multiple sclerosis patients should be reinterpreted.

In addition, susceptibility-weighted imaging utilizing deoxyhemoglobin as the contrast has revealed that venous blood in cerebral veins of multiple sclerosis patients is less deoxygenated compared with healthy controls.

Clin Exp Hypertens. 2008 Nov;30(8):711-9.

Cognitive decline and low blood pressure: the other side of the coin.
Maule S, Caserta M, Bertello C, Verhovez A, Naso D, Bisbocci D, Veglio F.

Division of Medicine and Hypertension, Department of Medicine and Experimental Oncology, S. Giovanni Battista Hospital, University of Torino, Torino, Italy. simmaule@tin.it

Low blood pressure has been found to be associated with cognitive decline and dementia in cross-sectional studies. Two mechanisms have been proposed to interpret this association: blood pressure levels decrease during the course of the dementia process, and low blood pressure induces or accelerates cognitive decline by lowering cerebral blood flow. Results of the prospective studies are contradictory. Low blood pressure and orthostatic hypotension have been found to predict cognitive impairment in the elderly population in some studies only. While hypotension may play a protective role in healthy elderly people, low blood pressure levels in frail elderly patients with associated diseases may cause cerebral hypoperfusion and accelerate cognitive decline.

PMID: 19021022 [PubMed - indexed for MEDLINE]

. However, recent findings of significant stenoses in the extracranial veins that drain the brain and spinal cord shed new light on these MR results. With the assumption that a majority, if not all, of multiple sclerosis patients exhibit such extracranial venous obstacles, the perfusion MR images of multiple sclerosis patients should be reinterpreted. Perhaps ongoing MR studies with respect to extracranial venous hemodynamics may decipher some of the unsolved puzzles related to this neurologic disease. (c) 2010 Wiley-Liss, Inc.