Acute-stage evolution of watershed infarction assessed on diffusion-weighted MR imaging.
BACKGROUND
To investigate acute stage (<5 days) evolution of the watershed infarction (WI) on diffusion-weighted (DW) magnetic resonance (MR) imaging and to evaluate the role of perfusion MR imaging in predicting the progression of watershed infarction.


METHODS
Twenty-eight patients with acute WI within 24 h after symptom onset were selected for this study. Criterion for WI was based on DW images. We assessed the infarct volume changes between the initial and follow-up (mean: 2.2 days) DW images. Perfusion images were obtained in 20 patients at the initial work-up and sensitivity, specificity, and accuracy of perfusion-diffusion mismatch in predicting severe infarct progression were evaluated. Clinical outcome was assessed by using National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS).


RESULTS
Infarct volumes on initial and follow-up DW images were 8.6+/-7.7 cm3 and 20.2+/-27.0 cm3, respectively. Twenty-one cases showed no or slight increment (<15 cm3) of infarct volume on follow-up MR imaging and seven cases showed severe progression (>15 cm3 increment). Among 20 cases in which perfusion maps were obtained, 5 cases showed perfusion-diffusion mismatch: among those, 4 developed severe progression of infarction. Severe progression group showed higher follow-up NIHSS score and poor outcome by 90-day mRS score.


CONCLUSIONS
WI usually begins as a small volume lesion, and progression of infarction during the acute stage is usually limited in most cases. Perfusion imaging may have an important role in predicting severe infarct progression in WI.
Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. sjkimjb@amc.seoul.kr
Sang Joon
SJ
Kim
Choong Wook
CW
Lee
Hyun Jeong
HJ
Kim
Jeong Hyun
JH
Lee
Deok Hee
DH
Lee
Choong Gon
CG
Choi
Dae Chul
DC
Suh
Dong-Wha
DW
Kang
D000368:Aged; D000369:Aged, 80 and over; D020520:Brain Infarction / Q000473:pathology* / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013997:Time Factors