Acute Corticonuclear Tract Ischemic Stroke with Isolated Central Facial Palsy.

OBJECTIVE: The clinical distinction between habitual facial asymmetry, early stage peripheral facial palsy, and isolated central facial palsy is sometimes difficult. The diagnosis of acute central facial palsy is of importance to identify patients for stroke work-up and appropriate treatment. We aimed to evaluate the prevalence and localization of acute ischemic lesions associated with isolated central facial palsy. METHODS: We screened our stroke database for patients presenting with isolated central facial palsy related to ischemic stroke between 2012 and 2017. All identified patients were comprehensively characterized including magnetic resonance (MR) diffusion-weighted imaging (DWI). RESULTS: We identified four out of 5169 patients (one male; 62-83 years) with isolated facial palsy as a result of acute ischemic stroke (NIHSS 1-2). All four had circumscribed DWI lesions in different regions of the corticonuclear tract in different areas with different etiologies. CONCLUSION: Isolated central facial palsy is a rare manifestation of acute ischemic stroke and may be missed if clinical suspicion is not raised. MR-DWI identifies small ischemic lesions in the corticonuclear tract, which results in appropriate diagnostic work-up and secondary prophylaxis.

FLAIR vascular hyperintensities and dynamic 4D angiograms for the estimation of collateral blood flow in posterior circulation occlusion.

INTRODUCTION: The objectives of this paper are to assess collateral blood flow in posterior circulation occlusion by MRI-based approaches (fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVHs), collateralization on dynamic 4D angiograms) and investigate its relation to ischemic lesion size and growth. METHODS: In 28 patients with posterior cerebral artery (PCA) and 10 patients with basilar artery (BA) occlusion, MRI findings were analyzed, with emphasis on distal FVH and collateralization on dynamic 4D angiograms. RESULTS: In PCA occlusion, distal FVH was observed in 18/29 (62.1%), in BA occlusion, in 8/10 (80%) cases. Collateralization on dynamic 4D angiograms was graded 1 in 8 (27.6%) patients, 2 in 1 (3.4%) patient, 3 in 12 (41.4%) patients, and 4 in 8 (27.6%) patients with PCA occlusion and 0 in 1 (10%) patient, 2 in 3 (30%) patients, 3 in 1 (10%) patient, and 4 in 5 (50%) patients with BA occlusion. FVH grade showed neither correlation with initial or follow-up diffusion-weighted image (DWI) lesion size nor DWI-perfusion-weighted imaging (PWI) mismatch ratio. Collateralization on dynamic 4D angiograms correlated inversely with initial DWI lesion size and moderately with the DWI-(PWI) mismatch ratio. The combination of distal FVH and collateralization grade on dynamic 4D angiograms correlated inversely with initial as well as follow-up DWI lesion size and highly with the DWI-PWI mismatch ratio. CONCLUSIONS: In posterior circulation occlusion, FVH is a frequent finding, but its prognostic value is limited. Dynamic 4D angiograms are advantageous to examine and graduate collateral blood flow. The combination of both parameters results in an improved characterization of collateral blood flow and might have prognostic relevance.

Sparing of the hippocampus indicates better collateral blood flow in acute posterior cerebral artery occlusion.

BACKGROUND: In acute posterior cerebral artery, occlusion involvement of the hippocampus is a common finding. Nevertheless, until today, infarction and ischemic lesion evolution in the hippocampus has not been studied systematically. AIM: Evaluation of hippocampal infarction patterns in posterior cerebral artery occlusion in the very early phase (≤six-hours) and ischemic lesion evolution on follow-up magnetic resonance imaging in relation to collateral blood flow assessed by a magnetic resonance imaging-based approach was conducted. METHODS: In 28 patients [mean age 69·4 ± 13·8 years, 19 (67·9%) males, 10 (32·1%) females] with proximal posterior cerebral artery occlusion, magnetic resonance imaging findings were analyzed, with emphasis on hippocampal infarction patterns on diffusion-weighted images and collateralization on dynamic 4D angiograms derived from perfusion-weighted raw images. RESULTS: On initial diffusion-weighted images, we identified all known hippocampal infarction patterns: type 1 (complete) in 6/18 (33·3%) patients, type 2 (lateral) in 10/18 (55·6%) patients, and type 3 (dorsal) and type 4 (circumscribed) in 1/18 (5·6%) patient respectively. On dynamic 4D angiograms, the grade of collateralization was classified as 1 in 9 (32·1%), 2 in 1 (3·6%), 3 in 10 (35·7%), and 4 in 8 (28·6%) patients. On follow-up diffusion-weighted images, we found new ischemic lesions in three and infarction growth in the hippocampus in five patients. Patients with better collateralization (grades 3 and 4) less often had hippocampal infarctions on initial (P = 0·003)/follow-up diffusion-weighted images (P = 0·046) as well as type 1 on initial (P = 0·007)/follow-up diffusion-weighted images (P = 0·005). CONCLUSIONS: Involvement of the hippocampus in proximal posterior cerebral artery occlusion is frequently but not obligatorily observed and highly dependent on the extent of collateralization. The same holds true for hippocampal infarction patterns.

Fluid Attenuated Inversion Recovery Vascular Hyperintensities Possibly Indicate Slow Arterial Blood Flow in Vertebrobasilar Dolichoectasia.

BACKGROUND AND PURPOSE: Vertebrobasilar dolichoectasia (VBD) is a dilatative arteriopathy associated with a decreased blood flow velocity. Fluid attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) is a phenomenon most likely representing slow arterial blood flow. We sought to examine the frequency and extent of FVH in VBD. METHODS: We analyzed magnetic resonance imaging (MRI) findings in 77 VBD patients with special emphasis on FVH in relation to the diagnostic MRI criteria of VBD and the etiology in symptomatic patients. RESULTS: In 49 (63.6%) VBD patients, FVH could be detected: in 22 (44.9%) a small hyperintense rim near the vessel wall (grade 1), in 20 (40.8%) a strong hyperintense rim near the vessel wall (grade 2), and in 7 (14.3%) the hyperintense signal filled the complete vessel lumen (grade 3). The diameter of the basilar artery moderately correlated with the extent of FVH. A higher FVH grade (2 and 3) was more common in patients with TIA/stroke related to VBD (9/16 [56.3%]) in comparison to patients with other etiology and asymptomatic patients (18/61 [29.5%]; P = .046). CONCLUSIONS: FVH may be useful to demonstrate the decreased blood flow velocity in VBD. More pronounced FVH in patients with posterior circulation TIA/stroke might reflect the underlying stroke pathomechanism.