Infarct volume on apparent diffusion coefficient maps correlates with length of stay and outcome after middle cerebral artery stroke.
BACKGROUND
Diffusion-weighted MRI (DWI) can depict acute ischemia based on decreased apparent diffusion coefficient (ADC) values. ADC maps, unlike DWI (which have contributions from T2 properties), solely reflect diffusion properties. Recent studies indicate that severity of neurological deficit corresponds with degree of ADC alteration.


OBJECTIVE
To determine whether infarct volume on ADC maps correlates with length of hospitalization and clinical outcome in patients with acute ischemic middle cerebral artery (MCA) stroke.


METHODS
Forty-five consecutive patients with acute (<or=72 h) MCA infarcts seen on DWI.


METHODS
Infarct volume was determined by counting pixels with ADC values >3 SDs below the average ADC value of a contralateral control region. Infarct volume was correlated with length of hospitalization and 6-month outcome assessed with Glasgow Outcome Scale (GOS), Modified Rankin Score (mRS), Barthel Index (BI) and a dichotomized outcome status with favorable outcome defined as GOS 1, mRS <or=1 and BI >or=95.


RESULTS
Infarct volume on ADC maps ranged from 0.2 to 187 cm(3) and was significantly correlated with length of hospitalization (p < 0.001, r = 0.67). Furthermore, ADC infarct volume was significantly correlated with GOS (r = 0.73), mRS (r = 0.68), BI (r = 0.67) and outcome status (r = 0.65) (each p < 0.001). Multiple logistic regression revealed a statistically significant correlation between ADC infarct volume and outcome status (p < 0.05), but none for Canadian Neurological Scale score, age and gender (p >0.05 each).


CONCLUSIONS
Infarct volume measured by using a quantitative definition for infarcted tissue on ADC maps correlated significantly with length of hospitalization (as a possible surrogate marker for short-term outcome) and functional outcome after 6 months. ADC infarct volume may provide prognostic information for patients with acute ischemic MCA stroke.
Engelter
Stefan T
ST
Department of Radiology, Duke University Medical Center, Durham, NC, USA. sengelter@uhbs.ch
Provenzale
James  M
J
Petrella
Jeffrey R
JR
DeLong
David M
DM
Alberts
Mark J
MJ
D000368:Aged; D001931:Brain Mapping; D004058:Diffusion; D005260:Female; D023261:Glasgow Outcome Scale; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology*; D007902:Length of Stay; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000209:etiology / Q000473:pathology* / Q000628:therapy*; D016896:Treatment Outcome