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Wake-up stroke and stroke of unknown onset: a critical review.

Wouters A, Lemmens R, Dupont P, Thijs V - Front Neurol (2014)

Bottom Line: Currently, this subset of patients is excluded from revascularization-therapy since no exact time of onset is known.The different imaging-selection criteria that can be used to treat these patients are discussed.Additional research on imaging findings associated with recent stroke and penumbral imaging will eventually lead to a shift from a rigid time-frame based therapy to a tissue-based individualized treatment approach.

View Article: PubMed Central - PubMed

Affiliation: KU Leuven Department of Neurosciences and Experimental Neurology, KU Leuven , Leuven , Belgium ; Department of Neurology, University Hospital Leuven , Leuven , Belgium ; Medical Imaging Research Center, UZ Leuven , Leuven , Belgium.

ABSTRACT
Patients, who wake up with an ischemic stroke, account for a large number of the total stroke population, due to circadian morning predominance of stroke. Currently, this subset of patients is excluded from revascularization-therapy since no exact time of onset is known. A large group of these patients might be eligible for therapy. In this review, we assessed the current literature about the hypothesis that wake-up-strokes occur just prior on awakening and if this subgroup differs in characteristics compared to the overall stroke population. We looked at the safety and efficacy of thrombolysis and interventional techniques in the group of patients with unknown stroke-onset. We performed a meta-analysis of the diagnostic accuracy of the diffusion-FLAIR mismatch in identifying stroke within 3 and 4.5 h. The different imaging-selection criteria that can be used to treat these patients are discussed. Additional research on imaging findings associated with recent stroke and penumbral imaging will eventually lead to a shift from a rigid time-frame based therapy to a tissue-based individualized treatment approach.

No MeSH data available.


Related in: MedlinePlus

Meta-analysis (47, 49–52) of the “strict” DWI/FLAIR mismatch pattern predicting stroke onset before 3 and 4 h. (A) shows the sensitivity and specificity for predicting stroke-onset before 3 h and (B) shows these values for stroke-onset before 4.5 h. *To predict stroke onset before 4.5 h the “liberal” method of DWI/FLAIR mismatch was used in the study of Petkova et al. (49).
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Figure 3: Meta-analysis (47, 49–52) of the “strict” DWI/FLAIR mismatch pattern predicting stroke onset before 3 and 4 h. (A) shows the sensitivity and specificity for predicting stroke-onset before 3 h and (B) shows these values for stroke-onset before 4.5 h. *To predict stroke onset before 4.5 h the “liberal” method of DWI/FLAIR mismatch was used in the study of Petkova et al. (49).

Mentions: A large multicenter observational study showed that the pattern of an acute ischemic lesion seen with DWI but not with FLAIR-imaging, decreases with longer time between onset of symptoms and MRI scanning (47). DWI/FLAIR mismatch had a sensitivity of 62%, a specificity of 78%, and a positive likelihood ratio of 3.6, for the detection of stroke patients within 4.5 h of stroke onset. In that study, a visual analysis was used that required complete absence of even subtle FLAIR lesions. In a later substudy (48), a more liberal visual rating system was used, in which subtle FLAIR lesions were still considered as DWI/FLAIR mismatch. This improved the sensitivity (0.86), but decreased the specificity (0.48) of this pattern to detect lesions within 4.5 h. The positive likelihood ratio for the liberal rating system was 2.6. The disadvantage of the liberal rating system is an increase in the interrater-variability for “subtle” FLAIR lesions. Figure 3 shows a meta-analysis of reported diagnostic studies that assessed the DWI/FLAIR mismatch pattern in relationship to time since onset in patients with precisely known symptom onset. The overall sensitivity of the DWI/FLAIR mismatch for detecting stroke within 3 h is 74% and within 4.5 h is 62%, with a specificity of 82% at both time points. The diagnostic accuracy is quite heterogeneous and may reflect differences in inclusion criteria, definitions of FLAIR/DWI mismatch, acquisition techniques, proportions of small, and infratentorial lesions between the studies.


Wake-up stroke and stroke of unknown onset: a critical review.

Wouters A, Lemmens R, Dupont P, Thijs V - Front Neurol (2014)

Meta-analysis (47, 49–52) of the “strict” DWI/FLAIR mismatch pattern predicting stroke onset before 3 and 4 h. (A) shows the sensitivity and specificity for predicting stroke-onset before 3 h and (B) shows these values for stroke-onset before 4.5 h. *To predict stroke onset before 4.5 h the “liberal” method of DWI/FLAIR mismatch was used in the study of Petkova et al. (49).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4129498&req=5

Figure 3: Meta-analysis (47, 49–52) of the “strict” DWI/FLAIR mismatch pattern predicting stroke onset before 3 and 4 h. (A) shows the sensitivity and specificity for predicting stroke-onset before 3 h and (B) shows these values for stroke-onset before 4.5 h. *To predict stroke onset before 4.5 h the “liberal” method of DWI/FLAIR mismatch was used in the study of Petkova et al. (49).
Mentions: A large multicenter observational study showed that the pattern of an acute ischemic lesion seen with DWI but not with FLAIR-imaging, decreases with longer time between onset of symptoms and MRI scanning (47). DWI/FLAIR mismatch had a sensitivity of 62%, a specificity of 78%, and a positive likelihood ratio of 3.6, for the detection of stroke patients within 4.5 h of stroke onset. In that study, a visual analysis was used that required complete absence of even subtle FLAIR lesions. In a later substudy (48), a more liberal visual rating system was used, in which subtle FLAIR lesions were still considered as DWI/FLAIR mismatch. This improved the sensitivity (0.86), but decreased the specificity (0.48) of this pattern to detect lesions within 4.5 h. The positive likelihood ratio for the liberal rating system was 2.6. The disadvantage of the liberal rating system is an increase in the interrater-variability for “subtle” FLAIR lesions. Figure 3 shows a meta-analysis of reported diagnostic studies that assessed the DWI/FLAIR mismatch pattern in relationship to time since onset in patients with precisely known symptom onset. The overall sensitivity of the DWI/FLAIR mismatch for detecting stroke within 3 h is 74% and within 4.5 h is 62%, with a specificity of 82% at both time points. The diagnostic accuracy is quite heterogeneous and may reflect differences in inclusion criteria, definitions of FLAIR/DWI mismatch, acquisition techniques, proportions of small, and infratentorial lesions between the studies.

Bottom Line: Currently, this subset of patients is excluded from revascularization-therapy since no exact time of onset is known.The different imaging-selection criteria that can be used to treat these patients are discussed.Additional research on imaging findings associated with recent stroke and penumbral imaging will eventually lead to a shift from a rigid time-frame based therapy to a tissue-based individualized treatment approach.

View Article: PubMed Central - PubMed

Affiliation: KU Leuven Department of Neurosciences and Experimental Neurology, KU Leuven , Leuven , Belgium ; Department of Neurology, University Hospital Leuven , Leuven , Belgium ; Medical Imaging Research Center, UZ Leuven , Leuven , Belgium.

ABSTRACT
Patients, who wake up with an ischemic stroke, account for a large number of the total stroke population, due to circadian morning predominance of stroke. Currently, this subset of patients is excluded from revascularization-therapy since no exact time of onset is known. A large group of these patients might be eligible for therapy. In this review, we assessed the current literature about the hypothesis that wake-up-strokes occur just prior on awakening and if this subgroup differs in characteristics compared to the overall stroke population. We looked at the safety and efficacy of thrombolysis and interventional techniques in the group of patients with unknown stroke-onset. We performed a meta-analysis of the diagnostic accuracy of the diffusion-FLAIR mismatch in identifying stroke within 3 and 4.5 h. The different imaging-selection criteria that can be used to treat these patients are discussed. Additional research on imaging findings associated with recent stroke and penumbral imaging will eventually lead to a shift from a rigid time-frame based therapy to a tissue-based individualized treatment approach.

No MeSH data available.


Related in: MedlinePlus