ABSTRACT
BACKGROUND: Few studies with a limited number of patients focused on the outcomes of patients with diffusion-weighted imaging (DWI)-negative acute ischemic stroke (AIS) after intravenous thrombolysis (IVT) and/or endovascular treatment (EVT). METHODS: This retrospective observational, single-center study included all consecutive patients admitted for AIS involving the anterior circulation and treated with IVT and/or EVT between January 1, 2015 and December 31, 2023. The collected data were used to identify the characteristics of patients with negative DWI and to compare outcomes in patients with negative and positive DWI. RESULTS: Among the 1210 patients included, 47 (3.9â¯%) had negative (DWI-negative group) and 1163 had increased DWI signal (DWI-positive group). In the DWI-negative group, the mean age was 69 years (SD=19.4), 55.3â¯% were men, and 27 (57.4â¯%) had a large vessel occlusion. Thirty eight (80.9â¯%) were treated with IVT alone, 7 (14.9â¯%) with EVT alone, and 2 (4.3â¯%) with both. Fluid attenuated inversion recovery (FLAIR) sequences were the most sensitive to detect predictive factors of cerebral ischemia, such as vessel thrombosis and the spaghetti sign that were found in 68.1â¯% and 83â¯%, of patients, respectively. Oxyhemoglobin-sensitive (T2*) and susceptibility-weighted angiography (SWAN) sequences were less sensitive: vessel thrombosis and the brush sign were detected in 55.3â¯% and 19.1â¯% of patients, respectively. Comparison of the two DWI groups showed that M2 occlusion was more frequent (31.9â¯% vs 13â¯%, p<0.001) and M1 occlusion rarer (19.1â¯% vs 36â¯%, p<0.02) in the DWI-negative than DWI-positive group. At admission, the median National Institutes of Health Stroke Scale score was lower in the DWI-negative than DWI-positive group (2 vs 6, p=0.0001), but the median symptom onset-to-MRI time was similar in both groups (108 vs 111 min, p=0.88). CONCLUSIONS: In patients with DWI-negative AIS, symptoms are less severe. Large vessel occlusions, notably in the M2 segment, are more distal at the expense of the M1 segment of MCA. The spaghetti sign remains the most predictive feature of AIS that should be specifically searched in the absence of DWI lesions.
ABSTRACT
BACKGROUND AND OBJECTIVES: Intraluminal thrombus (ILT) is a relatively rare cause of stroke. MRI/MRA is increasingly used for stroke patients eligible for acute treatment. Radiological ILT characteristics have never been studied systematically on MRA. We aimed to analyse signal changes and other radiological characteristics of ILT in the acute phase on MRA in a case series of ILT patients. MATERIALS AND METHODS: Consecutive stroke patients registered in our stroke database between January 2013 and September 2022 were screened for supra-aortic ILT on MRA, in whom MRA was the first supra-aortic vessel imaging performed. Twelve patients were included for analysis. Radiological analysis on MRA included ILT localisation, diameter of the free-floating ILT component, total ITL length, degree of stenosis caused by ILT, and ILT signal intensity. RESULTS: Median age was 65 years and 92% were men. Median time interval between stroke onset and MRA was 0.5 days. Atherosclerosis was the underlying ILT aetiology in half of the patients. The most frequent ILT localisation was the internal carotid artery, always involving the C1 segment. Median ILT diameter was 4.35 mm, median length 20.9 mm, median stenosis 65%, and with a homogeneous hypointensity of the ILT in 67% and a mixed hypo-hyperintensity in 33% (with ILT showing central hyperintensity surrounded by peripheral hypointensity). DISCUSSION: When observed on MRA, ILT showed a homogeneous hypointensity in two-thirds and a mixed hypo-hyperintensity in one third of patients. In future studies, follow-up MRA scans should be performed to analyse whether these signal changes are time-related or influenced by antithrombotic treatment for ILT.