ABSTRACT: Functional magnetic resonance imaging (fMRI) is used to assess language laterality in preoperative brain tumor patients. In postsurgical patients, susceptibility artifacts can potentially alter ipsilateral fMRI activation volumes and the assessment of language laterality. The purpose of this study was to investigate the ability of fMRI to correctly measure language dominance in brain tumor patients with previous surgery because this patient cohort is vulnerable to type II statistical errors and subsequent misjudgment of laterality.
Twenty-six right-handed patients with left-hemisphere gliomas (16 with and 10 without previous surgery) underwent preoperative language fMRI. Language laterality was measured using hemispheric and Broca's area regions of interest (ROIs). Hemisphere dominance, as established by laterality measurements, was compared with that determined by intraoperative electrocorticography and behavioral assessments.
Localization of primary language cortices was achieved in 24 of 26 patients studied. The hemisphere dominance evaluated by fMRI was verified by intraoperative corticography in only 14 patients (10 with and 4 without previous surgery), and only 12 of them had complete neuropsychological testing. Complete concordance of the laterality with intraoperative electrocorticography and behavioral assessments was found in patients without previous surgery. In patients with previous surgery, concordance was 75% using Broca's area ROI and 88% using hemispheric ROI, notwithstanding susceptibility artifacts. Differences in laterality between pre- and postsurgical patients, based on either hemispheric (P = 0.81) or Broca's area (P = 0.19) ROI measurements were not statistically significant. However, hemispheric ROI analyses were found to be less affected by postsurgical artifacts and may be more suitable for establishing hemisphere dominance.
fMRI mapping of eloquent language cortices in brain tumor patients after surgery is feasible and can serve as a useful baseline evaluation for preoperative neurosurgical planning. However, findings should be interpreted with caution in the presence of postsurgical artifacts.
Neurosurgery 03/2009; 64(4):644-52; discussion 652-3. · 2.79 Impact Factor
ABSTRACT: The purpose of this work was to study the feasibility of incorporating functional magnetic resonance imaging (fMRI) information for intensity modulated radiotherapy (IMRT) treatment planning of brain tumors. Three glioma patients were retrospectively replanned for radiotherapy (RT) with additional fMRI information. The fMRI of each patient was acquired using a bilateral finger-tapping paradigm with a gradient echo EPI (Echo Planer Imaging) sequence. The fMRI data were processed using the Analysis of Functional Neuroimaging (AFNI) software package for determining activation volumes, and the volumes were fused with the simulation computed tomography (CT) scan. The actived pixels in left and right primary motor cortexes (PMCs) were contoured as critical structures for IMRT planning. The goal of replanning was to minimize the RT dose to the activation volumes in the PMC regions, while maintaining a similar coverage to the planning target volume (PTV) and keeping critical structures within accepted dose tolerance. Dose-volume histograms of the treatment plans with and without considering the fMRI information were compared. Beam angles adjustment or additional beams were needed for 2 cases to meet the planning criteria. Mean dose to the contralateral and ipsilateral PMC was significantly reduced by 66% and 55%, respectively, for 1 patient. For the other 2 patients, mean dose to contralateral PMC region was lowered by 73% and 69%. In general, IMRT optimization can reduce the RT dose to the PMC regions without compromising the PTV coverage or sparing of other critical organs. In conclusion, it is feasible to incorporate the fMRI information into the RT treatment planning. IMRT planning allows a significant reduction in RT dose to the PMC regions, especially if the region does not lie within the PTV.
Medical dosimetry: official journal of the American Association of Medical Dosimetrists 02/2008; 33(1):42-7. · 1.26 Impact Factor
Clinical studies suggest that acupuncture can stimulate saliva production and reduce xerostomia (dry mouth). We were interested in exploring the neuronal substrates involved in such responses.
In a randomized, sham acupuncture controlled, subject blinded trial, twenty healthy volunteers received true and sham acupuncture in random order. Cortical regions that were activated or deactivated during the interventions were evaluated by functional magnetic resonance imaging (fMRI). Saliva production was also measured.
Unilateral manual acupuncture stimulation at LI-2, a point commonly used in clinical practice to treat xerostomia, was associated with bilateral activation of the insula and adjacent operculum. Sham acupuncture at an adjacent site induced neither activation nor deactivation. True acupuncture induced more saliva production than sham acupuncture.
Acupuncture at LI-2 was associated with neuronal activations absent during sham acupuncture stimulation. Neuroimaging signal changes appear correlated to saliva production.
BMC Complementary and Alternative Medicine. 01/2008;