The Role of the Signal Intensity Ratio on Fluid-Attenuated Inversion Recovery in Stroke Patients Achieving Successful Recanalization with Endovascular Treatment.
BACKGROUND
This study aimed to investigate whether fluid-attenuated inversion recovery (FLAIR) imaging hyperintensity can be used as a surrogate marker for the severity of ischemic insult and predict lesion growth.


METHODS
Based on a prospective stroke registry database, we identified patients with ischemic stroke who were treated with endovascular treatment (EVT) within 8 hours of onset and achieved successful recanalization (modified thrombolysis in cerebral infarction ≥2B). FLAIR hyperintensity was measured using the signal intensity ratio (SIR), defined as the mean SIR of diffusion-restricted lesions to the corresponding areas in the contralateral hemisphere. Lesion growth was defined as the ratio of final infarct volume on follow-up FLAIR to initial infarct volume on diffusion-weighted imaging.


RESULTS
For 69 patients meeting the eligibility criteria, the median FLAIR SIR was 1.17 (interquartile range, 1.08-1.23) and the median lesion growth ratio was 1.70 (interquartile range, 1.35-2.79) (Pearson's r = -.146, P = .231). In multiple linear regression models, the FLAIR SIR was not significantly correlated with the lesion growth ratio. Interestingly, the time interval from initial magnetic resonance imaging (MRI) to successful recanalization was independently correlated with the lesion growth ratio (β = .072, P < .001). With respect to clinical outcomes, the FLAIR SIR was not associated with either discharge modified Rankin scale score ≤2 (β = -3.41, P = .30) or symptomatic hemorrhagic transformation (β = 2.75; P = .63).


CONCLUSIONS
Contrary to our hypothesis, FLAIR hyperintensity on initial MRI before EVT was not associated with lesion growth in patients who were recanalized successfully with EVT. Instead, our results suggest that time interval from MRI acquisition to recanalization is an independent predictor of lesion growth.
College of Medicine, Seoul National University, Seoul, Republic of Korea.
Taehoon
T
Kim
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Jong-Won
JW
Chung
Department of Neurology, Stroke Center, Seoul National University Bundang Hospital, College of Medicine, Seoul National University, Seongnam, Republic of Korea.
Myung Suk
MS
Jang
Department of Neurology, Stroke Center, Seoul National University Bundang Hospital, College of Medicine, Seoul National University, Seongnam, Republic of Korea.
Mi Hwa
MH
Yang
Department of Neurology, Stroke Center, Seoul National University Bundang Hospital, College of Medicine, Seoul National University, Seongnam, Republic of Korea.
Sang-Hwa
SH
Lee
Department of Neurology, Stroke Center, Seoul National University Bundang Hospital, College of Medicine, Seoul National University, Seongnam, Republic of Korea.
Beom Joon
BJ
Kim
Department of Neurology, Stroke Center, Seoul National University Bundang Hospital, College of Medicine, Seoul National University, Seongnam, Republic of Korea.
Moon-Ku
MK
Han
Department of Radiology, Stroke Center, Seoul National University Bundang Hospital, College of Medicine, Seoul National University, Seongnam, Republic of Korea.
Jae Hyoung
JH
Kim
Department of Radiology, Stroke Center, Seoul National University Bundang Hospital, College of Medicine, Seoul National University, Seongnam, Republic of Korea.
Cheolkyu
C
Jung
Department of Neurology, Seoul National University Boramae Medical Center, Seoul, Republic of Korea.
Jae-Sung
JS
Lim
Department of Neurology, Stroke Center, Seoul National University Bundang Hospital, College of Medicine, Seoul National University, Seongnam, Republic of Korea. Electronic address: braindoc@snu.ac.kr.
Hee-Joon
HJ
Bae
D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D016009:Chi-Square Distribution; D016208:Databases, Factual; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004185:Disability Evaluation; D018450:Disease Progression; D057510:Endovascular Procedures / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012042:Registries; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020521:Stroke / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D061665:Time-to-Treatment; D016896:Treatment Outcome
Ischemic stroke; endovascular treatment; fluid-attenuated inversion recovery; infarct volume; magnetic resonance imaging