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Published on: September 25, 2019
Hippocampal lesion patterns in acute posterior cerebral artery stroke: clinical and MRI findings
Kristina Szabo1, Alex Förster, Theodor Jäger
1Department of Neurology, Universitätsklinikum Mannheim, Theodor-Kutzer-Ufer, 68137 Mannheim, Germany. szabo@neuro.ma.uni-heidelberg.de
Background And Purpose:
Reports of ischemic stroke affecting the hippocampus are rare. In this study we used diffusion-weighted MRI (DWI) to characterize patients with posterior circulation stroke involving the hippocampus.
Methods:
Fifty-seven consecutive acute stroke patients with hippocampal infarct (HI) on DWI were analyzed with regard to clinical features and ischemic lesion patterns. The last 20 of these underwent additional neuropsychological testing of short-term, working, and episodic long-term memory.
Results:
We found unilateral HI in 54 and bilateral HI in 3 patients. Visual analysis identified 4 patterns of DWI lesion affecting (1) the complete hippocampus (15/60), (2) the lateral (19/60) or (3) dorsal (22/60) parts of the hippocampal body and tail, and (4) circumscribed lesions in the lateral hippocampus (4/60), corresponding well to hippocampal vascular anatomy. In all cases DWI showed further ischemic lesions in the posterior circulation. Symptoms from lesions outside the hippocampus were the common leading clinical signs. Whereas mnestic deficits were prominent in only 11/57 patients, neuropsychological examination in 20 patients showed deficits of verbal episodic long-term memory in left and of nonverbal episodic long-term memory in right HI.
Conclusions:
Several phenotypic lesion patterns can be distinguished in HI that usually occur as part of multifocal PCA ischemia. A careful neuropsychological examination is necessary to detect resulting memory deficits.
Insights
Diffusion-weighted MRI (DWI) revealed distinct patterns of hippocampal infarct (HI) in posterior circulation stroke. Neuropsychological testing is crucial for detecting memory deficits resulting from these rare but significant brain injuries.
Area of Science:
- Neurology
- Neuroimaging
- Neuropsychology
Background:
- Ischemic stroke affecting the hippocampus is uncommon.
- Diffusion-weighted MRI (DWI) is utilized to study these rare cases.
Purpose of the Study:
- To characterize patients with posterior circulation stroke involving the hippocampus using DWI.
- To identify patterns of hippocampal infarct (HI) and associated clinical and cognitive deficits.
Main Methods:
- Analysis of 57 acute stroke patients with hippocampal infarct on DWI.
- Clinical features and ischemic lesion patterns were assessed.
- Neuropsychological testing of memory functions in 20 patients.
Main Results:
- Four distinct DWI lesion patterns were identified, correlating with hippocampal vascular anatomy.
- Unilateral HI was observed in 54 patients, bilateral in 3.
- While overt memory deficits were infrequent, neuropsychological testing revealed specific verbal and nonverbal episodic long-term memory impairments.
Conclusions:
- Phenotypic lesion patterns in hippocampal infarcts can be distinguished.
- These infarcts typically occur as part of multifocal posterior cerebral artery (PCA) ischemia.
- Thorough neuropsychological examination is essential for identifying memory deficits.
