Hyperintense vessels on FLAIR: A useful non-invasive method for assessing intracerebral collaterals
Introduction
Hyperintense vessels (HV) on fluid-attenuated inversion recovery (FLAIR) MR images refer to focal hyperintension. HV can be frequently observed near the cerebral surface along the cortical sulci in patients with ischemic stroke [1], [2], [3], [4]. Although HV have non-invasively diagnostic value for intracerebral artery steno-occlusive lesion [2], the influence of degree of stenosis on the presence of HV is unclear. A recent study revealed that HV are associated with slow collateral blood flow in the setting of acute ischemic stroke [5], though the correlation of the location of HV with the patterns of collaterals is still unclear.
Atherosclerotic steno-occlusive disease in the M1 segment of the middle cerebral artery (MCA) can recruit the different patterns of collaterals, including the low grade of leptomeningeal retrograde collateral from anterior cerebral artery (ACA) to MCA and the high grade of leptomeningeal retrograde collateral from posterior cerebral artery (PCA) to MCA [6], [7]. These patterns of collaterals may provide a setting helping to understand the underlying mechanism of HV. In this study, we aimed to investigate the relationship between the location of HV and these patterns of collaterals by contemporaneously comparing findings on FLAIR images with digital subtraction angiography (DSA) in the setting of patients with atherosclerotic steno-occlusive disease in M1 segment of MCA.
Section snippets
Subjects
A total of 233 consecutive patients with atherosclerotic steno-occlusive lesions in M1 segment of the MCA were inclused as subjects, of which 57 were diagnosed with transient ischemic attacks (TIA), and 176 with cerebral infarctions (CI). These patients were retrieved from the Nanjing Stroke Registry Program (NSRP) between January 2004 and April 2010. The detailed profile of NSRP has been previously published elsewhere [8]. Inclusion criteria included: (1) initial presence of transient or
Results
A total of 233 patients (age, 59.4 ± 10.8 years) with symptomatic atherosclerotic steno-occlusive lesions of the M1 segment were included. There were 16 of these patients presented with ischemic lesions in bilateral hemispheres, so the total number of the symptomatic hemispheres were 249 (TIA, n = 59; CI, n = 190). There were 11 asymptomatic steno-occlusive lesions in the M1 segment, number of M1 steno-occlusive lesions were 260. Because 8 patients were observed the HV in the bilateral territories of
Discussion
In this study, we retrospectively selected patients, who were initially diagnosed as atherosclerotic steno-occlusive lesions in the M1 segment according to patients’ clinical characteristics, magnetic resonance angiogram and/or T2 weighted MR imaging (detecting the steno-occlusive lesions of the horizontal portion of MCA at the level of basal cistern). To achieve revascularization of the M1 segment by angioplasty and stenting, these patients were further performed with standard DAS.
This study
Conclusion
This study indicated that the HV show up at a degree of M1 stenosis of greater than or equal to 90%, and more importantly, the location of HV are indicators of the different patterns of collaterals. The HV could assess non-invasively the patterns of collaterals in patients with steno-occlusive lesions in the M1 segment of MCA.
Acknowledgements
This study was supported by Natural Science Foundation of China (NSFC #30870848 to GX and NSFC #30870847 to XL).
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These two authors contributed equally to this work.