MRI Study On Amyotrophic Lateral Sclerosis

Part Ⅰ : Study of FLAIR imaging on amyotrophic lateralsclerosisPurposes: To study the MR FLAIR T2WI features in patients with amyotrophic lateral sclerosis and its possible correlation with duration and clinical dyration and clinical scale.Materials and Methods: 28 patients (14 males and 14 females;age range 28~66 years, mean age 48.56±10.47 years, duration range 3 ~ 48 months, mean duration 14.85±10.87 months) with definite or probable ALS (defined by the diagnostic criteria of El Escorial World Federation of Neurology, and evaluated by Norris Scale and Amyotrophic Lateral Sclerosis Functional Rating Scale) and 25 age and gender matched normal controls (15 males, 10 females, age range 36~62 years, mean age 50.64±7.96 years) were enrolled, all the participants have no other diseases or any recent medicine treatment. MRI was performed using 1.5 T and 3.0 T GE scanner (GE Medical System, Milwaukee, Wisconsin, USA) (axial T1WI, T2WI, FLAIR T2WI, and coronal FLAIR T2WL). FLAIR T2 signals of corticospinal tracts (CST) at the level of posterior limb of the internal capsule, subcortical white matter in precentral cortex (SWM), and primary motor cortex (PMC) were acquired and graded by signal intensity. The patients were divided into 3 groups by the disease duration.Results: Compared with those in normal subjects, ALS patients had higher incidency of hyperintense signal on FLAIR T2WI in CST (57.14% vs 44.00%, P>0.05), obvious high signal in CST (17.86% vs 0.00%, P<0.05), SWM at precentral gyri (85.71% vs 12.00%, P<0.01), and motor dark line (MDL) in precentral gyri (82.14% vs 16.00%, P<0.01). CST signal change showed difference among various disease duration groups (x2=10.10, P=0.03). The duration group 2 had highest incidence of hyperintensity signal in CST (76.47 %, 13/17).Conclusions: The symmetric slight hyperintense signal on FLAIR T2WI in CST is less specific, but ALS is suggested when obvious T2 high signal is present.Hyperintense signal in SWM and MDL on FLAIR T2WI are relatively special changes in ALS patients. Symmetric hyperintense signal in CST is seen most frequently during 6-20 months in ALS patient, but signal grade can not reflect the clinical scale.Part II: Study of blood oxygenation level dependent fMRI onamyotrophic lateral sclerosisPurposes: To study the blood oxygenation level dependent fMRI (BOLD-fMRI) features of amyotrophic lateral sclerosis patients while executeing thumb-finger opposition movement.Materials and Methods: 15 patients (6 males and 9 females;age range 30~ 62 years, mean age 51.33±10.12 years) with definite or probable ALS (defined by the diagnostic criteria of El Escorial World Federation of Neurology) and 15 age and gender matched normal controls (7 males, 8 females, age range 37~60 years, mean age 49.47±7.37 years) were enrolled, all the participants are right-handed with no other diseases or any recent medicine treament. Subjects executed thumb-finger opposition movement with the frequency 1-2 Hz during a 3 blocks motor task: move 30s, then rest 30s, repeat 3time. The subjects were scanned in a 3.0 Tesla scanner (GE Medical System, Milwaukee, Wisconsin, USA) with a standard GE headcoil. The functional images were acquired using a gradient echo single shot EPI sequence with TE/TR/flip angle=35ms/3s/90°. Thirty-six slices (3mm thickness, 0.5 mm gap, field of view 220mm and matrix 64><64) parallel to the AC-PC line covering the full brain were examined. Structural MRI was acquired using a 3D-FSPGR sequence. The fMRI data were analyzed using SPM2.Results: Bilateral primary sensorimotor cortex (PSM), bilateral premotor area (PA), bilateral supplementary motor area (SMA), bilateral parietal region (PAR), contralateral inferior lateral premotor area (ILPA) and ipsilateral cerebellum showed activation in both ALS patients and normal contrals when executing the same motor task. The activation areas in bilateral PSM, bilateral PA,bilateral SMA, and ipsilateral cerebellum were significantly larger in ALS patients than in normal controls (PO.05), ipsilateral ILPA, bilateral posterior limb of internal capsule and contralateral cerebellum were extra activation areas, only in ALS patients.Conclusions: The similer activation areas were activated in both groups while executing same motor task. The increased activation areas in ALS patients in these areas may represent neural reorganization, but the extra activation areas in ALS patients may indicate functional compensation.Part HJ: Study of proton magnetic resonance spectroscopy('H-MRS) on amyotrophic lateral sclerosisPueposes: To study the proton magnetic resonance spectroscopy ('H-MRS) features of amyotrophic lateral sclerosis and its relation with clinical scale and to provide references for clinical diagnosis.Materials and Methods: 15 patients (6 males and 9 females;age range 30~ 62 years, mean age 51.33±10.12 years) with definite or probable ALS (defined by the diagnostic criteria of El Escorial World Federation of Neurology, and evaluated by Norris Scale and Amyotrophic Lateral Sclerosis Functional Rating Scale) and 15 age and gender matched normal controls (7 males, 8 females, age range 37 ~ 60 years, mean age 49.47±7.37 years) were enrolled, all the participants had no other diseases or any recent medicine treament. 'H-MRS was performed on a 3.0 T GE imaging system (GE Medical System, Milwaukee, Wisconsin, USA). FSE T2-weighted MR images of the brain were acquired in axial, sagital and coronal plane of the subcortex motor area, posterior limb of the internal capsule for localization of the spectroscopic acquisition. TE-Averaged Point Resolved Selective Spectroscopy was used. N-acetylaspartate (NAA), creatine (Cr), Glu and Glx (glutamate + glutamine) values of subcortex motor area and posterior limb of the internal capsule were acquired, Mest was used to compare differences between groups, the correlations between the above values and clinical scale were analysed.Results: The primary motor cortex and posterior limb of the internal capsule of ALS patients had lower NAA/Cr (1.91±0.34,1.53±0.17) compared with normal subjects (2.23±0.33, 1.66±0.07), the differences between groups were statistically significant (p=0.00,0.01). ALS patients had higher Glu/Cr (0.34±0.05,0.29±0.06) and Glx/Cr (0.40±0.04, 0.33±0.06), compared with normal subjects (0.30±0.03, 0.25±0.04) and (0.32±0.05, 0.26±0.03), the differences between groups were statistically significant (p=O.00, 0.00). The Norris Scale was negatively correlated with Glx/Cr of primary motor cortex by lineal correlation analysis (r=-0.75), and this correlation had statistically significant (F=16.6, P=0.00).Conclusion: Neuronal loss and Glu+Gln increase can be detected by using proton MRS in ALS patients. 'H-MRS is an useful tool in reflecting the characteristic changes of metabolite in ALS.