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The present study reported a significant CCT (cerebral circulation time) increase in MS patients compared to control subjects, indicating a consistent condition of cerebral hypoperfusion. Increase of CCT, and the fol- lowing cerebral hypoperfusion, vary with blood in-flow reduction due to stenosis and/or parenchymal high resistance, changing PaCO2, or alteration of the cerebral perfusion pressure.
cheerThe strong CCT value difference between control group and MS patients explains hypoperfusion, which preempts myelin breakdown and MRI detectable white matter lesions.
The absence of a significant association between CCT and disease duration, disease onset, lesion and brain volume, EDSS and age could suggest that the high intravascular resistance is a constant finding in MS patients, possibly taking place at an early stage of the disease. Therefore, cerebrovascular changes are not solely the result of a late chronic inflammatory process. Indeed, if the microvascular dysfunction was a consequence of lesion load or brain atrophy, high CCT values would be expected to increase with EDSS and disease duration.
In conclusion, the absence of a correlation between lesion volume and CCT confirms that hemodynamic alteration is not related to parenchymal lesion and other MS-linked clinical fea- tures, but rather, is a pathognomonic feature of disease.