Arteriovenous brain malformations: is functional MR imaging reliable for studying language reorganization in patients? Initial observations.
OBJECTIVE
To determine whether the blood flow abnormalities frequently associated with arteriovenous malformations (AVMs) can alter functional magnetic resonance (MR) imaging evaluation of language lateralization and whether reorganization of language function occurs in patients with brain AVMs.


METHODS
Eleven patients with left-hemisphere brain AVMs and 10 age-matched control subjects were examined with 1.5-T blood oxygen level-dependent (BOLD) functional MR imaging. Verbal fluency, sentence repetition, and story listening tasks were performed. The functional MR imaging laterality index in the frontal and temporal lobes was defined as the (L - R)/(L + R) ratio, where L and R are the numbers of activated pixels in the left and right hemispheres, respectively. Statistical analyses were performed with Wilcoxon signed rank, Fisher exact, and Kruskal-Wallis tests.


RESULTS
Control subjects had left-sided language dominance, although symmetric pixel counts were observed in the frontal lobes in two subjects and in the temporal lobes in one subject. Six patients had left-sided language dominance similar to that observed in control subjects. Five of these patients had AVMs outside frontal or temporal language areas, without flow abnormalities. Five patients had abnormally right-sided asymmetric indexes (below mean control subject value - 2 SDs), which suggested language reorganization (P <.05). Results of Wada examination and/or postembolization functional MR imaging performed in two of these patients showed that the abnormal laterality indexes were at least partly due to severe flow abnormalities that impaired detection of BOLD MR imaging signal intensity.


CONCLUSIONS
These data suggest that flow abnormalities may interfere with language lateralization assessment with functional MR imaging.
Lehéricy
Stéphane
S
Department of Neuroradiology, Hôpital de la Salpêtrière, 47 Boulevard de l'Hôpital, 75013 Paris, France. stephane.lehericy@psl.ap-hop-paris.fr
Biondi
Alessandra
A
Sourour
Nader
N
Vlaicu
Michaela
M
du Montcel
Sophie Tézenas
ST
Cohen
Laurent
L
Vivas
Elio
E
Capelle
Laurent
L
Faillot
Thierry
T
Casasco
Alfredo
A
Le Bihan
Denis
D
Marsault
Claude
C
D000328:Adult; D015901:Angiography, Digital Subtraction; D001931:Brain Mapping; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D004292:Dominance, Cerebral; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002538:Intracranial Arteriovenous Malformations / Q000503:physiopathology*; D007807:Language Tests; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D013067:Speech Perception; D018709:Statistics, Nonparametric; D013702:Temporal Lobe / Q000503:physiopathology*