Michal Bittšanský

PURPOSE: To investigate the apparent diffusion constant (ADC) as a prospective magnetic resonance imaging (MRI) marker of early degeneration in articular cartilage. MATERIALS AND METHODS: Early degenerative changes were studied using in vitro MRI on cartilage-bone specimens excised from human femoral condyles. The loss of proteoglycans developed in vivo due to a degenerative process was compared with a gadolinium diethylenetriamine pentaacetate anion (Gd-DTPA(2-)) enhanced decrease of T(1) relaxation times, and with an increase of ADCs and T(2) relaxation times. RESULTS: Contrast enhanced T(1) values decreased and the diffusion constants increased in cartilage regions with depleted proteoglycans. The relative changes in diffusion constants were smaller than those of Gd-DTPA(2-) enhanced T(1), and in some proteoglycan-depleted regions no changes in the diffusion constants were detected. T(2) relaxation times showed considerable spatial variability that did not correlate with proteoglycan concentration. CONCLUSION: In contrast to Gd-DTPA(2-) enhanced T(1), which reflects changes in chemical composition, diffusion constants may reflect structural degradation of the cartilage matrix.

The objectives of this work were to compare concentrations of N-acetylaspartate (NAA), glutamate (Glu), glutamine (Gln), Glx (=Glu + Gln), myo-inositol (mI), total creatine (Cre) and other metabolites in the temporal lobes of patients with mesial temporal lobe epilepsy (mTLE), cryptogenic TLE (cTLE), who show no abnormalities in high-resolution MRI, and healthy controls using single voxel (1)H MRS at 3 T. Twelve patients with mTLE, nine with cTLE and 22 controls were investigated using a short echo time STEAM protocol. Voxels were positioned bilaterally in the medial and lateral temporal lobes. Spectra were processed with LCModel. Significantly lower mean NAA were detected in mTLE patients (P < 0.001) and a trend towards lower NAA in cTLE patients compared to controls (P = 0.053). Glx was not different between groups. Estimates of Glu showed a different metabolic pattern in mTLE with elevated Glu in lateral compared with medial voxels on the ipsilateral side to seizure onset (P = 0.019). MI concentrations were significantly lower in cTLE (P < 0.001) and in mTLE patients (P = 0.005) compared with healthy controls. MI/Cre was significantly reduced in cTLE patients only (P = 0.004). The results confirm low NAA in mTLE and to a lesser extent in cTLE patients. MI and mI/Cre were identified as potential metabolic indicators of the epileptogenic area in cTLE.

OBJECTIVES: Disturbances in the hypothalamo-pituitary axis are supposed to modulate activity of multiple sclerosis (MS). We hypothesised that the extent of HYP damage may determine severity of MS and may be associated with the disease evolution. We suggested fatigue and depression may depend on the degree of damage of the area. METHOD: 33 MS patients with relapsing-remitting and secondary progressive disease, and 24 age and sex-related healthy individuals (CON) underwent 1H-MR spectroscopy (1H-MRS) of the hypothalamus. Concentrations of glutamate + glutamin (Glx), cholin (Cho), myoinositol (mIns), N-acetyl aspartate (NAA) expressed as ratio with creatine (Cr) and NAA were correlated with markers of disease activity (RIO score), Multiple Sclerosis Severity Scale (MSSS), Depressive-Severity Status Scale and Simple Numerical Fatigue Scale. RESULTS: Cho/Cr and NAA/Cr ratios were decreased and Glx/NAA ratio increased in MS patients vs CON. Glx/NAA, Glx/Cr, and mIns/NAA were significantly higher in active (RIO 1-2) vs non-active MS patients (RIO 0). Glx/NAA and Glx/Cr correlated with MSSS and fatigue score, and Glx/Cr with depressive score of MS patients. In CON, relationships between Glx/Cr and age, and Glx/NAA and fatigue score were inverse. CONCLUSION: Our study provides the first evidence about significant hypothalamic alterations correlating with clinical outcomes of MS, using 1H-MRS. The combination of increased Glu or mIns with reduced NAA in HYP reflects whole-brain activity of MS. In addition, excess of Glu is linked to severe disease course, depressive mood and fatigue in MS patients, suggesting superiority of Glu over other metabolites in determining MS burden.