Capillary Transit Time Heterogeneity Is Associated with Modified Rankin Scale Score at Discharge in Patients with Bilateral High Grade Internal Carotid Artery Stenosis.

Sibu Mundiyanapurath,Sascha Diatschuk,Kim Mouridsen,Mikkel Bo Hansen,Peter Arthur Ringleb,Alexander Radbruch,Leif Østergaard,Martin Bendszus,Wolfgang Wick

doi:10.1371/journal.pone.0158148

Abstract

Background and PurposePerfusion weighted imaging (PWI) is inherently unreliable in patients with severe perfusion abnormalities. We compared the diagnostic accuracy of a novel index of microvascular flow-patterns, so-called capillary transit time heterogeneity (CTH) to that of the commonly used delay parameter Tmax in patients with bilateral high grade internal carotid artery stenosis (ICAS).MethodsConsecutive patients with bilateral ICAS ≥ 70%NASCET who underwent PWI were retrospectively examined. Maps of CTH and Tmax were analyzed with a volumetric approach using several thresholds. Predictors of favorable outcome (modified Rankin scale at discharge 0–2) were identified using univariate and receiver operating characteristic (ROC) curve analysis.ResultsEighteen patients were included. CTH ≥ 30s differentiated best between patients with favorable and unfavorable outcome when both hemispheres were taken into account (sensitivity 83%, specificity 73%, area under the curve [AUC] 0.833 [confidence interval (CI) 0.635; 1.000]; p = 0.027). The best discrimination using Tmax was achieved with a threshold of ≥ 4s (sensitivity 83%, specificity 64%, AUC 0.803 [CI 0.585;1.000]; p = 0.044). The highest AUC was found for left sided volume with CTH ≥ 15s (sensitivity 83%, specificity 91%, AUC 0.924 [CI 0.791;1.000]; p = 0.005).ConclusionThe study suggests that CTH is superior to Tmax in discriminating ICAS patients with favorable from non-favorable outcome. This finding may reflect the simultaneous involvement of large vessels and microvessels in ICAS and underscore the need to diagnose and manage both aspects of the disease.

Highlights

In ischemic stroke, brain tissue is damaged by hypoxia resulting from severe hypoperfusion
capillary transit time heterogeneity (CTH) 30s differentiated best between patients with favorable and unfavorable outcome when both hemispheres were taken into account (sensitivity 83%, specificity 73%, area under the curve [Area under the curve (AUC)] 0.833 [confidence interval (CI) 0.635; 1.000]; p = 0.027)
The best discrimination using Tmax was achieved with a threshold of 4s

Summary

Introduction

Brain tissue is damaged by hypoxia resulting from severe hypoperfusion This perfusion deficit has been studied using perfusion weighted imaging (PWI) for many years [1,2]. Measurement of cerebral blood flow (CBF), cerebral blood volume, mean transit time (MTT) and time-to-peak have been used to characterize perfusion in stroke [2], and more recently, the time to the maximum of the residue curve (Tmax) has been introduced as a surrogate of hypoperfused tissue [6,7]. We compared the diagnostic accuracy of a novel index of microvascular flow-patterns, so-called capillary transit time heterogeneity (CTH) to that of the commonly used delay parameter Tmax in patients with bilateral high grade internal carotid artery stenosis (ICAS)

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Conclusion