Arterial Hyperintensity on Fast Fluid-attenuated Inversion Recovery Images: A Subtle Finding for Hyperacute Stroke Undetected by Diffusion-weighted MR Imaging
Masayuki Maeda
,a,
Tatsuya Yamamotoa,
Shouichiro Daimona,
Hajime Sakumaa and
Kan Takedaa
a From the Department of Radiology, Mie University School of Medicine (M.M., H.S., K.T.), and the Departments of Radiology (T.Y.) and Internal Medicine (S.D.), Maizuru Kyosai Hospital.

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FIG 1. Case 10. MR images of 75-year-old man, with right hemiparesis, scanned 3 hours (AC) and 3 days (D) after symptom onset.
A, Diffusion-weighted (4999/126/1, b = 1000) MR image shows high signal intensity in the left MCA territory (arrows), suggesting the infarction pertinent to this episode.
B, Fast-FLAIR (8000/110/1, TI = 1800) image shows arterial hyperintensity in the left sylvian fissure (arrow). Note that there is chronic infarction that occurred 7 weeks before this stroke (arrowhead).
C, Contrast-enhanced T1-weighted (500/12/2) image shows arterial enhancement more extensively than does the arterial hyperintensity exhibited in B (arrows).
D, Fast-FLAIR (8000/110/1, TI = 1800) image shows a hyperintense area of acute infarction at 3 days after onset (arrowhead). Note that the arterial hyperintensity seen at 3 hours disappears at this time.
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FIG 2. Case 11. MR images of a 65-year-old man, with right-arm weakness, scanned 3 hours (AC) and 3 days (D and E) after symptom onset.
A and B, Diffusion-weighted MR images (4999/126/1, b = 1000) are negative for stroke 3 hours after onset.
C, Fast-FLAIR (8000/110/1, TI = 1800) image shows arterial hyperintensity in the left MCA territory (arrow). This is the only abnormal finding pertinent to the patient's symptoms at the initial MR examination.
D and E, Fast-FLAIR (8000/110/1, TI = 1800) images show extensive acute infarction in the left MCA territory 3 days after onset (arrows).
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