Leptomeningeal collateral flow (LMF) is associated with infarct area and clinical outcome for ischemic stroke patients. Although LMF can be detected by multiple imaging methods, but their diagnostic performance is uncertain. The aim of this study was to evaluate the diagnostic validity or reliability of noninvasive image methods in assessing LMF. Databases included PubMed, Web of Science, Embase, and Cochrane Library. Original observational cohort studies. Ischemic stroke patients. Different noninvasive image methods to assess LMF. Newcastle–Ottawa Scale to evaluate the quality of the studies; forest plot to show pooled results; I 2 and Egger test to evaluate the heterogeneity and publication bias. Thirty of the 126 selected studies were eligible. For CT angiography, the interobserver agreement ranged from 0.494 to 0.93 and weighted kappa was 0.888; for patients receiving thrombolysis or endovascular treatment, 0.68 to 0.91; 0.494 to 0.89 for the 2-point system, 0.60 to 0.93 for the 3-point system, 0.68 to 0.87 for the system of >4 points; area under the curve (AUC) was 0.78. For perfusion computed tomography (CTP), the interobserver agreement ranged from 0.724 to 0.872; for patients receiving thrombolysis or endovascular treatment, 0.74 to 0.872; 0.724 for the 2-point system, 0.783 to 0.953 for the 3-point system; the intraobserver agreement was 0.884; AUC was 0.826. For MRI-fluid attenuated inversion recovery (FLAIR), the interobserver agreement ranged from 0.58 to 0.86; for patients receiving thrombolysis or endovascular treatment, 0.75 to 0.86; 0.86 for the two-point system, 0.77 to 0.87 for the system of more than 5 points; AUC was 0.82. No pooled data of CTP and FLAIR. The difference cohort study had difference bias. The unpublished data were not included. CT angiography is a good tool for assessing LMF. CTP shows a good validity and reliability, but its diagnostic value needs more evidence. FLAIR is a good modality to assess LMF. These image methods had better validity and reliability to evaluate LMF of patients receiving thrombolysis or endovascular treatment than all ischemic stroke patients.

To evaluate the clinical potential of a non-contrast-enhanced magnetic resonance angiography (NCE-MRA) technique using flow-sensitive dephasing (FSD)-prepared steady-state free precession (SSFP), FSD-NCE-MRA, for hand arterial angiography in patients with rheumatoid arthritis. Twenty-four patients were recruited and underwent FSD-NCE-MRA on a 1.5T MR system. For comparison, conventional dynamic CE-MRA was also conducted after the FSD-NCE-MRA scan. Images obtained by both FSD-NCE-MRA and CE-MRA were independently evaluated by two experienced radiologists using a four-point scale and the hand arteries were divided into wrist, palm and finger segments for image quality assessment. Signal-to-noise ratio (SNR), artery-to-muscle contrast-to-noise ratio (CNR), and vessel sharpness of superficial/deep palmar arch and common digital artery were also measured by a physician. Experimental results demonstrated that FSD-NCE-MRA yielded a higher percentage of diagnostic value arterial segments than CE-MRA (96 vs. 83 %, P \ 0.05). Besides, average SNR, CNR, and vessel sharpness were also higher on FSD-NCE-MRA images than CE-MRA ones (SNR: 57 ± 13 vs. 15 ± 4; CNR: 54 ± 13 vs. 13 ± 4; sharpness: 1.1 ± 0.1 vs. 0.9 ± 0.1; all P \ 0.05). Thus, FSD-NCE-MRA allows a higher image quality in the depiction of the hand arterial tree for the patients with rheumatoid arthritis compared to CE-MRA. The technique, FSD-NCE-MRA, may be a safe and improved clinical