Diffusion-Weighted-Imaging Negative Stroke Syndromes

Abstract

Objective: Normal diffusion-weighted imaging (DWI) during the acute symptomatic phase of an ischemic stroke is a rare, but a well-known phenomenon. The exact rate and the clinical correlates of this phenomenon are not satisfactorily elucidated.

Materials and Methods: Consecutive patients who were hospitalized with the diagnosis of acute ischemic stroke in the last 10 years and who had DWI (with a bmax of 1000 s/mm²) in the first 12 hours were included. A systematic review of published DWI-negative stroke cases and case series was performed. Alternate diagnoses including transient ischemic attack or stroke mimics such as seizure, migraine, functional disorders, and post-stroke recrudescence were excluded.

Results: The diagnosis of DWI-negative stroke syndrome was made in 20 (1.3%) of 1.506 patients hospitalized in Hacettepe Hospitals. A literature search disclosed another 535 (6.6%) DWI-negative strokes out of 8.101 cases. A total of 115, identified in case reports and cohort (n=19) articles, were combined with our cases to delineate further characteristics of DWI-negative clinical stroke syndromes. DWI-negative syndromes (n=135) were “brainstem mini-strokes” (31.1%), “cortical small embolic infarcts” (5.2%), “pure penumbral stroke” (normal DWI with magnetic resonance perfusion deficit) (34.8%); “aborted stroke” (early and fully recanalized stroke, only diagnosable in patients with documented acute vessel occlusion) (5.2%); and “miscellaneous” (23.7%). Corresponding clinical stroke syndromes include partial hemispheric deficits (36.1%), focal cortical syndromes (4.3%), caudal brainstem syndromes (9.3%), acute isolated vertigo (9.3%), vertigo-plus syndromes (10.1%), ocular syndromes (7.4%), movement disorders (1.9%), typical lacunar syndromes (11.1%), and atypical lacunar syndromes such as ataxia ± dysatrhria (9.3%).

Conclusion: In clinical practice of acute ischemic stroke, early DWI imaging can be negative in various clinical syndromes. Imaging repetition is necessary for the diagnosis and management plan of these patients.

Approval was obtained from Hacettepe University Non-Interventional Clinical Research Ethics Committee for this study (decision number: 2020/16-25, date: 06/10/2020)

Due to the retrospective nature of the study no informed consent was obtained from patients. Only ethics committee board approval was gathered.

Externally and internally peer-reviewed.

Surgical and Medical Practices: M.Y.P., E.M.A., R.G., K.K.O., M.A.T., Concept: M.Y.P., E.M.A., R.G., K.K.O., M.A.T., Design: M.Y.P., E.M.A., M.A.T., Data Collection or Processing: M.Y.P., M.A.T., Analysis or Interpretation: M.Y.P., E.M.A., R.G., K.K.O., M.A.T., Literature Search: M.Y.P., M.A.T., Writing: M.Y.P., E.M.A., R.G., K.K.O., M.A.T.

No conflict of interest was declared by the authors.

The authors declared that this study received no financial support.