Abstract
Digital subtraction angiography (DSA) is often used to evaluate the morphological and pathological changes of cerebral arteries in clinical practice. This study aims to explore the possibility of assessing cerebral hypoperfusion with DSA in patients with carotid stenosis. Thirty patients with a mild to severe stenosis on one side, and a mild stenosis on the other side of the carotid artery were recruited. Frontal, parietal, temporal and occipital lobes were chosen as regions of interest for measuring the quantitative perfusion parameters from their time-density curves (TDCs) of DSA images. The perfusion parameters were compared between the two hemispheres by using paired t-test. In addition, the bilateral asymmetry of these parameters was calculated and its correlation with the bilateral asymmetry in stenosis was analyzed. The parameters included mean transit time (MTT), time of contrast uptake (TU), time taken to the half peak value (1/2TMAX), area under the curve (AUC) were significantly prolonged at the severe stenosis side than those at the mild stenosis side in frontal lobe (P=0.013; P=0.041; P=0.009; P=0.027) and parietal lobe (P=0.008; P=0.041; P=0.002; P=0.012). The asymmetric ratios of MTT and AUC showed statistically significant correlations with stenosis asymmetry in all four lobes. MTT, TU, 1/2TMAX and AUC could reflect the bilateral asymmetry of the cerebral perfusion. These DSA parameters, therefore, may be used for the evaluation of cerebral hypoperfusion caused by carotid stenosis.
Highlights
Atherosclerotic stenosis in carotid artery is a major etiology of ischemic stroke [Zaidat, Alexander, Suarez et al (2004); Taussky, Sangala, Meyer et al (2011)]
Previous studies indicate that time-density curve (TDC) calculated from digital subtraction angiography (DSA) parametric imaging could represent the dynamic density changes of contrast passing a region of interest (ROI) [Hunter, Hunter and Brown (1985); Bürsch (1983)]
time of enhancing duration (TD) of frontal, temporal and occipital lobes (ICC=0.512; intraclass correlation coefficient (ICC)=0.528; ICC=0.528), average fitting slope (AFS) of all four lobes (ICC=0.507; ICC=0.530; ICC=0.516; ICC=0.573) as well as maximum slope (MS) of the temporal lobe (ICC=0.495), showed moderate agreements (Tab. 2). This result demonstrates that the DSA perfusion parameters calculated from the two groups of ROIs by different observers show good consistency with each other
Summary
Atherosclerotic stenosis in carotid artery is a major etiology of ischemic stroke [Zaidat, Alexander, Suarez et al (2004); Taussky, Sangala, Meyer et al (2011)]. Certain quantitative parameters extracted from TDC, such as cerebral circulation time (CCT) was verified to reflect hemodynamic changes within the ROIs and had good correlations with CT/MR perfusion parameters [Lin, Hung, Chang et al (2016); Lin, Hsu, Lin et al (2016)]. The main objective of this study is to investigate the feasibility of using DSA to quantify cerebral perfusion in patients with carotid stenosis. Eleven quantitative parameters were extracted from the TDCs within ROIs of frontal, parietal, temporal and occipital lobes. The differences of these parameters between two sides of the different lobes within each group were compared and the correlations between the stenosis asymmetry and the asymmetry ratios of these parameters were investigated
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