Stability of large diffusion/perfusion mismatch in anterior circulation strokes for 4 or more hours.
BACKGROUND
The stability of hypoperfused brain tissue in stroke patients with major artery occlusions is unknown. The purpose of this study was to determine the persistence of a diffusion/perfusion mismatch in patients with ICA or proximal MCA occlusions.


METHODS
Fourteen patients with ICA and/or proximal MCA occlusion and a diffusion/perfusion mismatch at presentation were studied. All were enrolled in a pilot randomized study of normobaric oxygen therapy. None received thrombolytic therapy; 8 received normobaric oxygen and 6 room air. Diffusion/perfusion MRI was performed at baseline, 4 hours, 24 hours, and 1 week. Abnormal DWI, ADC, and MTT volumes were determined using standard image analysis methods.


RESULTS
The mean time from symptom onset to baseline MRI was 7.5 +/- 1 hours. Across all 4 time points there was a significant difference in DWI lesion (ANOVA, P < 0.0001) and abnormal MTT volumes (ANOVA, P < 0.01) with the 24 hour and 1 week abnormal volumes different from the earlier studies. However, comparing baseline and 4 hour scans, there was no significant interval change in the mean abnormal DWI volume (29.4 +/- 8.2 ml vs. 28.1 +/- 7.4 ml) or abnormal MTT volumes (137 +/- 17.7 ml vs. 130.9 +/- 13.8). By 24 hours, only 2 patients did not maintain a mismatch of 20% or greater.


CONCLUSIONS
Patients who present outside the time window for thrombolytic therapy, and who have a large diffusion/perfusion mismatch on MRI may have a stable mismatch for 4 or more hours.
Neuroradiology Division, Department of Radiology, Massachusetts General Hospital, Boston, Harvard Medical School, Boston, MA 02114, USA. rggonzalez@partners.org
R Gilberto
RG
González
Reza
R
Hakimelahi
Pamela W
PW
Schaefer
Luca
L
Roccatagliata
A Gregory
AG
Sorensen
Aneesh B
AB
Singhal
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001921:Brain / Q000098:blood supply / Q000473:pathology*; D002340:Carotid Artery Diseases / Q000150:complications / Q000473:pathology / Q000628:therapy; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010102:Oxygen Inhalation Therapy; D010291:Paresis / Q000209:etiology / Q000473:pathology / Q000628:therapy; D010865:Pilot Projects; D012720:Severity of Illness Index; D020521:Stroke / Q000150:complications / Q000473:pathology* / Q000628:therapy; D013997:Time Factors