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Abstract
Background Post-stroke diffusion weighted imaging (DWI) signal transformation of the infarct core, which results in high apparent diffusion coefficient (ADC) values and variable DWI signal intensity, is completed no later than 1 month after onset of ischemia. We observed frequent exceptions to this timeline of change in DWI signal, which led to uncertainties in further clinical patient management.
Methods A prospective single-center study of patients treated with mechanical thrombectomy of a large vessel occlusion in the anterior circulation was conducted. Patients received high-resolution MRI at 3T, including DWI, in the acute post-stroke phase and in the follow-up after 3–12 months.
Results Overall, 78 patients (45 men) of mean age 63.6 years were evaluated. We identified persisting or new diffusion restriction in 29 of the 78 patients (37.2%) on follow-up imaging. Diffusion restrictions in a different location from the infarct core, representing new (sub-)acute ischemia, were observed in four patients (5.1%). Smaller areas of persisting diffusion restriction (pDWI lesions with high DWI signal and reduced ADC values) within the former infarct core were observed in 25 patients (32.1%) without clinical evidence of recurrent stroke, but with worse outcome scores at follow-up compared with patients without pDWI lesions. The presence of pDWI lesions is associated with a large primary infarct core (multivariate regression OR 1.03 (95% CI 1.01 to 1.05); p<0.01), mediating the relationship between pDWI lesions and clinical outcome.
Conclusion Smaller foci of persisting diffusion restriction (pDWI lesions) in the follow-up after endovascular treatment for stroke are frequent and likely represent a slowed ADC signal progression within a formerly large infarct core.
- Stroke
- MRI
- Brain
- Lesion
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information.
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Footnotes
Contributors Study conception and design: MRHP, TB-B, MTB with substantial contributions from all authors. Data collection: MRHP, TB-B, CM, KB, SH, BI, DS, SW, CZ, MTB. Analysis and interpretation of results: MRHP, TB-B, MTB with substantial contributions from all authors. Manuscript preparation: MRHP, MTB. All authors critically revised the manuscript for important intellectual content and approved the final version of the manuscript. All authors agree to be accountable for all aspects of the work. MTB acts as the guarantor of this work.
Funding This work is supported by a KKF grant from the Technical University of Munich to MRHP.
Competing interests Outside the submitted work, CZ has received speaker honoraria from Bayer-Schering. He serves as a co-editor on the advisory board of Clinical Neuroradiology and is president of the German Society of Neuroradiology (DGNR). All the other authors declare no conflict of interest.
Provenance and peer review Not commissioned; externally peer reviewed.
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