Vessel Size Imaging Reveals Pathological Changes of Microvessel Density and Size in Acute Ischemia

Abstract

The aim of this study was to test the feasibility of vessel size imaging with precise evaluation of apparent diffusion coefficient and cerebral blood volume and to apply this novel technique in acute stroke patients within a pilot group to observe the microvascular responses in acute ischemic tissue. Microvessel density-related quantity Q and mean vessel size index (VSI) were assessed in 9 healthy volunteers and 13 acute stroke patients with vessel occlusion within 6 hours after symptom onset. Our results in healthy volunteers matched with general anatomical observations. Given the limitation of a small patient cohort, the median VSI in the ischemic area was higher than that in the mirrored region in the contralateral hemisphere (P < 0.05). Decreased Q was observed in the ischemic region in 2 patients, whereas no obvious changes of Q were found in the remaining 11 patients. In a patient without recanalization, the VSI hyperintensity in the subcortical area matched well with the final infarct. These data reveal that different observations of microvascular response in the acute ischemic tissue seem to emerge and vessel size imaging may provide useful information for the definition of ischemic penumbra and have an impact on future therapeutic approaches.

The Potential of Microvessel Density in Prediction of Infarct Growth: A Two-Month Experimental Study in Vessel Size Imaging

“…The result of the study (with a large patient cohort, a broader time window of 24 h and a presence of PI-DWI mismatch) coincided with our previous pilot study [11] and a rat study [13]: the reduced microvessel density and increased mean vessel radius were observed in IPE compared to the HEA (fig. 2).…”

“…Differences in vessel density between gray and white matter have been showed in healthy volunteers in our feasibility study [11]. This explains the broad range of the voxel-wise histograms in figure 3a.…”

“…The calculation of the quantitative VSI is based on the combined estimations of cerebral blood volume (CBV), apparent diffusion coefficient (ADC) and Q [7]. So far, this technique has been reported to characterize cerebral tumor vascularization [7,8,9,10] and recently also showed great potentials when applied to ischemic stroke [11]. Two animal studies have reported the changes of microvessel density and size during vascular remodeling after experimental stroke [12,13].…”

Advances in Stroke

“…Ультразвуковые методы исследования [34,35] и МРТ с высоким разреше-нием позволяют обнаружить бляшки, ассоцииро-ванные с высоким риском развития инсульта [36]. Новая методика "визуализации размера сосуда" имеет достаточно возможностей для демонстрации патологических изменений в микроциркуляторном русле на фоне ишемии [37]. Воспаление в атеро-склеротических бляшках можно определить с помо-щью [18F]-2-фтор-2-дезокси-d-глюкоза позитронно-эмиссионной томографии и МР-методов диагности-ки [38].…”

“…36 A new technique of "vessel size imaging" has the potential to demonstrate pathological changes in the microvasculature during ischemia. 37 Inflammation in atherosclerotic plaques can be identified by both [18F]-2-fluoro-2-deoxy-d-glucose positron emission tomography and MRI techniques. 38 [18F]-2-Fluoro-2-deoxy-dglucose selectively detects inflammatory portions of arteriosclerotic plaques, which is an indicator of macrophage load, inflammatory activity, and collagenolytic plaque destabilization 39 as the source of microemboli and vessel wall inflammation as the cause of spontaneous cervical artery dissection.…”