INTRODUCTION In our experience, tools as fMRI and H1-MRI spectroscopy may add valuable information to the standard clinical assessment and prognosis in patients characterized vegetative state (VS), minimally conscious state (MCS) and severe disability (SD). Such information could have an impact on clinical decision making, may guide therapeutic options and could be used to stream rehabilitation programs. AIM We used fMRI to study both the presence and the degree of functional activation in VS and MCS and SD patients and tried to discover any possible changes in the markers of neuronal turn-over by H1-MRI spectroscopy. MATERIALS & METHODS We enrolled 24 patients (age comprised between 17 and 58) with outcome of comas: 20 of them had polytrauma outcomes, 3 of them had cerebral anoxia, 1 of them had encephalitis outcome. Each patient underwent morphological, fMRI and H1-MRS spectroscopy analysis. A 3T Signa Excite system and an 8 channel phased array coil were used to acquire morphological sequences fMRI and H1-MRS spectroscopy. fMRI. Functional (Axial Single Shot, SS, EchoPlanar Image, EPI, Gradient Echo, GE), and morphological (isovolumetric SPoiled GRass - Inversion Recovery, SPGR-IR) sequences were acquired. We used a block paradigm of the kind: 30 s stimulus vs 30 s rest, for a total length of 5 min. Three different paradigms were applied: 1) in the stimulus phase, the patient heard the voice of a relative telling an emotionally significant episode, vs silence; 2) in the stimulus phase, the patient heard the same voice telling the same episode as in point 1), but the voice was played in the reverse order, vs silence; 3) in the stimulus phase, the patient heard the same voice as in 1), whereas in the rest phase the patient heard the same reverse voice as in point 2). fMRI analysis was performed off-line by using BrainWave GE proprietary software. Briefly, the processing of this software is semi-automatic and consists in segmentation and coregistration of the morphologic sequence to the fMRI sequence, after the appropriate corrections (motion correction, smoothing, etc.). The final parametric maps were calculated at a p<0.01 threshold and superimposed to the morphological coregistered segmented images. Spectroscopy (Single voxel, Point-Resolved Spectroscopy Sequence, PRESS). We analyzed the following metabolite ratios: mI/Cr, Cho/Cr, NAA/Cr, NAA/Cho. Resulting spectra were processed by SAGE Software (Spectral Analysis, GE Medical System). Particularly, we focused on NAA/Cho ratio, because it has been showed that a reduction of this ratio has a negative prognostic value. We compared the NAA/Cho values obtained in VS/MCS/SD patients with the corresponding values obtained in 16 healthy volunteers (age comprised between 25 and 57), by placing the voxel in the left frontal white matter. Normal NAA/Cho reference values were in the range of 2.0 ± 0.3. RESULTS fMRI. When present, activations were located in the temporal lobes, mono or bilaterally depending of the characteristics of the cerebral lesions. Patients were divided in two groups: the ones showing clear-cut activations (15 patients, 65%) and the ones showing no activation (8 patients, 35%). H1-MRS spectroscopy. Considering the NAA/Cho ratios, we divided patients in three groups: NAA/Cho ratios ≤ 1 (undoubtedly pathologic), NAA/Cho ratios in the range between 1.1 and 1.6 (moderately pathologic), and NAA/Cho ratios ≥ 1.7 (normal). Considering the NAA/Cho ratio of the 15 activated patients, five (33%) of them showed a NAA/Cho ratio ≤ 1, six (40%) of them showed a NAA/Cho ratio in the range between 1.1 and 1.6, and four (27%) of them showed a NAA/ Cho ratio ≥ 1.7. Considering the NAA/Cho ratio of the 8 patients showing no activation, three (38%) of them showed a NAA/Cho ratio ≤ 1, five (62%) of them showed a NAA/Cho ratio in the range between 1.1 and 1.6, and no one (0%) showed a NAA/Cho ratio ≥ 1.7. DISCUSSION When taking...

The prognostic value of fMRI and H1-MRS spectroscopy in the study of patients in vegetative state.

CEVOLANI, DANIELA;AGATI, RAFFAELE;BATTISTINI, ALBERTO;PIPERNO, ROBERTO;LEONARDI, MARCO
2010

Abstract

INTRODUCTION In our experience, tools as fMRI and H1-MRI spectroscopy may add valuable information to the standard clinical assessment and prognosis in patients characterized vegetative state (VS), minimally conscious state (MCS) and severe disability (SD). Such information could have an impact on clinical decision making, may guide therapeutic options and could be used to stream rehabilitation programs. AIM We used fMRI to study both the presence and the degree of functional activation in VS and MCS and SD patients and tried to discover any possible changes in the markers of neuronal turn-over by H1-MRI spectroscopy. MATERIALS & METHODS We enrolled 24 patients (age comprised between 17 and 58) with outcome of comas: 20 of them had polytrauma outcomes, 3 of them had cerebral anoxia, 1 of them had encephalitis outcome. Each patient underwent morphological, fMRI and H1-MRS spectroscopy analysis. A 3T Signa Excite system and an 8 channel phased array coil were used to acquire morphological sequences fMRI and H1-MRS spectroscopy. fMRI. Functional (Axial Single Shot, SS, EchoPlanar Image, EPI, Gradient Echo, GE), and morphological (isovolumetric SPoiled GRass - Inversion Recovery, SPGR-IR) sequences were acquired. We used a block paradigm of the kind: 30 s stimulus vs 30 s rest, for a total length of 5 min. Three different paradigms were applied: 1) in the stimulus phase, the patient heard the voice of a relative telling an emotionally significant episode, vs silence; 2) in the stimulus phase, the patient heard the same voice telling the same episode as in point 1), but the voice was played in the reverse order, vs silence; 3) in the stimulus phase, the patient heard the same voice as in 1), whereas in the rest phase the patient heard the same reverse voice as in point 2). fMRI analysis was performed off-line by using BrainWave GE proprietary software. Briefly, the processing of this software is semi-automatic and consists in segmentation and coregistration of the morphologic sequence to the fMRI sequence, after the appropriate corrections (motion correction, smoothing, etc.). The final parametric maps were calculated at a p<0.01 threshold and superimposed to the morphological coregistered segmented images. Spectroscopy (Single voxel, Point-Resolved Spectroscopy Sequence, PRESS). We analyzed the following metabolite ratios: mI/Cr, Cho/Cr, NAA/Cr, NAA/Cho. Resulting spectra were processed by SAGE Software (Spectral Analysis, GE Medical System). Particularly, we focused on NAA/Cho ratio, because it has been showed that a reduction of this ratio has a negative prognostic value. We compared the NAA/Cho values obtained in VS/MCS/SD patients with the corresponding values obtained in 16 healthy volunteers (age comprised between 25 and 57), by placing the voxel in the left frontal white matter. Normal NAA/Cho reference values were in the range of 2.0 ± 0.3. RESULTS fMRI. When present, activations were located in the temporal lobes, mono or bilaterally depending of the characteristics of the cerebral lesions. Patients were divided in two groups: the ones showing clear-cut activations (15 patients, 65%) and the ones showing no activation (8 patients, 35%). H1-MRS spectroscopy. Considering the NAA/Cho ratios, we divided patients in three groups: NAA/Cho ratios ≤ 1 (undoubtedly pathologic), NAA/Cho ratios in the range between 1.1 and 1.6 (moderately pathologic), and NAA/Cho ratios ≥ 1.7 (normal). Considering the NAA/Cho ratio of the 15 activated patients, five (33%) of them showed a NAA/Cho ratio ≤ 1, six (40%) of them showed a NAA/Cho ratio in the range between 1.1 and 1.6, and four (27%) of them showed a NAA/ Cho ratio ≥ 1.7. Considering the NAA/Cho ratio of the 8 patients showing no activation, three (38%) of them showed a NAA/Cho ratio ≤ 1, five (62%) of them showed a NAA/Cho ratio in the range between 1.1 and 1.6, and no one (0%) showed a NAA/Cho ratio ≥ 1.7. DISCUSSION When taking...
2010
340
340
Cevolani D.; Maffei M.; Agati R.; Battistini A.; Piperno R.; Leonardi M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/101626
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