AJDRAJNR - American Journal of Neuroradiology

This Article
Right arrow Abstract Freely available
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Toyoda, K.
Right arrow Articles by Fukuda, K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Toyoda, K.
Right arrow Articles by Fukuda, K.

Fluid-attenuated Inversion Recovery Intraarterial Signal: An Early Sign of Hyperacute Cerebral Ischemia

Keiko Toyodaa, Masahiro Idaa and Kunihiko Fukudaa

a From the Department of Radiology (K.T., K.F.), Jikei University School of Medicine, and the Department of Radiology (M.I.), Tokyo Metropolitan Ebara Hospital.



View larger version (150K):

[in a new window]
  		FIG 1. A 78-year-old woman who underwent imaging 35 minutes after onset of right hemiparesis and aphasia.

A and B, FLAIR images (8000/10/1 [TR/TE/excitation]), TI = 2000) show contiguous intraarterial signal, which is hyperintense to cerebral parenchyma in M1, M2, and M3 segments of the left middle cerebral artery (arrows).

C, MR angiogram (32/6.8, flip angle = 15 degrees) shows corresponding lack of TOF effect in M1, M2, and M3 segments of the left middle cerebral artery.

D, Diffusion-weighted image (500/123/1, b = 1200) shows faintly hyperintense lesion localized in the area fed by left lateral lenticulostriate artery (arrow); however, there is no change in the hemispheric territory of the left middle cerebral artery.

E, Postcontrast MR angiogram (32/6.8, flip angle = 15 degrees) shows intraluminal enhancement in the left middle cerebral artery except for in the distal potion of the M1 segment. Arrow indicates complete obstruction in distal portion of left M1 segment.

F, T2-weighted image (4500/96/1) obtained 7 days after onset confirmed final infarction is in the entire territory of the left middle cerebral artery. Note the diffusion-weighted lesion is still smaller than the area of intraarterial signal distribution. Intraarterial signal consists of not only complete obstruction but also slow flow. The area of final infarct corresponds to the area of intraarterial signal distribution.



View larger version (174K):

[in a new window]
  		FIG 2. A 71-year-old woman who underwent imaging 7 hours after onset of right hemiparesis and aphasia.

A and B, FLAIR images (8000/10/1, TI = 2000) show intraarterial signal in M1, M2, and M3 segments of the left middle cerebral artery (arrows).

C, MR angiogram (32/6.8, flip angle = 15 degree) demonstrates lack of TOF in the left internal carotid and middle cerebral arteries.

Perfusion imaging (not shown) showed a hypoperfused area with increased time-to-peak and mean transit time values in the left middle cerebral artery territory as large as the area of intraarterial signal distribution and lack of TOF.

D, Diffusion-weighted image (500/123/1, b = 1200) shows hyperintense lesion in the left basal ganglia and insular cortex.

E, Postcontrast MR angiogram (32/6.8, flip angle = 15 degrees) shows intraluminal enhancement in the left middle cerebral artery except for in the M1 segment. Arrow indicates complete obstruction in the left M1 segment.

F, Final infarction is confirmed in the basal ganglia and insular cortex by CT performed 9 days after stroke symptom onset, corresponding to the initial lesion seen on diffusion-weighted images.

Note lesion in D is smaller than the area of intraarterial signal distribution. Intraarterial signal consists of not only complete obstruction but also slow collateral circulation. The area of final infarct is smaller than that of intraarterial signal distribution. Ischemic penumbra may be present in the mismatch between the intraarterial signal distribution and the diffusion-weighted lesion.



View larger version (98K):

[in a new window]
  		FIG 3. A 59-year-old man who presented with homonymous hemianopsia. MR imaging was performed 13 hours after stroke symptom onset.

A, MR angiogram (32/6.8, flip angle = 15 degrees) shows lack of TOF in the right posterior communicating artery.

B, On FLAIR images (8000/10/1, TI= 2000), intraarterial signal is visible in the right posterior cerebral artery (arrow); however, signal is discontinuous and isointense to cerebral parenchyma. Final infarction was confirmed in the posterior cerebral territory on T2-weighted image (not shown) obtained 14 days after stroke symptom onset. Note that FLAIR is inferior to MR angiography in detecting occluded artery.



View larger version (94K):

[in a new window]
  		FIG 4. An 83-year-old woman who underwent imaging 23.5 hours after onset of loss of consciousness.

A, MR angiogram (32/6.8, flip angle = 15 degree) shows occlusion in distal portion of M1 segment of the right middle cerebral artery.

B, FLAIR image (8000/10/1, TI = 2000) already shows hyperintense lesion and cortical swelling in the right middle cerebral artery territory. Intraarterial signal (arrows) is shown in the right middle cerebral artery corresponding to lack of TOF; however, signal is hampered by narrowed sulci owing to vasogenic edema.



View larger version (102K):

[in a new window]
  		FIG 5. A 62-year-old man who underwent imaging 2.5 hours after onset of loss of consciousness and left hemiparesis.

A and B, FLAIR images (8000/10/1, TI = 2000) show intraarterial signal in the M1 (arrows), M2 (arrowheads), and M3 (thin long arrows) segments of the right middle cerebral artery. Old infarction proceeds in the right insular cortex.

C and D (same level as in A and B), T2-weighted images (4500/96/1) show lack of flow void in M1 (arrows) and M2 (arrowheads) segments; however, evidence of flow void is visible in the M3 segment (thin long arrows).

MR angiogram (not shown) shows lack of TOF in the right middle cerebral artery. CT confirmed final infarction in both perforator and hemispheric-branch territories of the right middle cerebral artery.





Copyright © 2009 by the American Society of Neuroradiology. Print ISSN: 0195-6108 Online ISSN: 1936-959X