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Rationale and Objectives: This study's aims were to depict changes in cartilage quality after surgical intervention using magnetic resonance (MR) examination and in content of glycosaminoglycans chains (GAGs) after two types of surgeries - chondral defect treatment by microfractures and scaffold implantation in combination with microfractures.Materials and Methods: Twenty-five patients were studied: 14 with implants, 11 with microfractures. MR examination was made before surgery and 6, 12, and 18 months thereafter. Qualitative changes in cartilage were observed by means of delayed gadolinium enhanced magnetic resonance imaging of cartilage sequence using Gd-DTPA2- and Gd-DOTA. In each examination, GAGs content was determined at three locations: the defect, its surroundings, and a non-load-bearing reference area.Results: Measured indices showed no statistically significant differences in changes within the defect area when comparing the two treatment types at individual time points of 6, 12, and 18 months. In the case of microfracture treatment, more substantial decrease in GAGs concentration occurred at month 6, whereas the greatest decline occurred at month 12 when using an implant. Change in GAGs content and decline in cartilage quality were substantial also in the reference area and close surroundings.Conclusions: Hyaline cartilage behaves as a unified whole, and change in GAGs content was marked also in locations with no morphological damage. Over the monitored period, no statistically significant difference between treatment types was noted as measured by GAGs content in the defect or its close surroundings. dGEMRIC is suitable for monitoring cartilage quality even if use of Gd-DTPA2- is not possible, because comparable results were achieved using Gd-DOTA. [ABSTRACT FROM AUTHOR]

The necessity of using non-Newtonian models for hemodynamics in geometries mimicking large vessels is investigated. Phase-contrast magnetic resonance imaging (PC-MRI) measurements are performed on a specially-designed phantom representing the aorta while using several types of fluids. These measurements are compared against the results of the lattice Boltzmann method (LBM) computational fluid dynamics (CFD) simulator in 3D. On the phantom side, two types of non-Newtonian fluids (water-based solutions of glycerine with xanthan gum and sucrose with xanthan gum) and Newtonian fluid (clear water) are used in the experiments; three different acrylic plates are inserted to represent aortic stenosis of varying degrees; and two constant flow regimes with high and low flow rates are used. The CFD simulations in the geometry and inflow boundary conditions corresponding to each experiment are performed both with non-Newtonian and Newtonian approaches. Additionally, the accuracy of the PC-MRI flow measurements is assessed and discussed with respect to the known PC-MRI flow underestimation due to turbulence. Based on the type of stenosis and inflow rate, the results indicate that the Newtonian models produce comparable results with the experimentally acquired data, which is in favor of overall less expensive Newtonian models. [ABSTRACT FROM AUTHOR]

We evaluated the clinical utility of cardiac magnetic resonance imaging (CMR) combined with a novel high-sensitivity troponin T assay (hs-cTnT) in the diagnosis of inflammatory cardiomyopathy. CMR, measurement of hs-cTnT, and endomyocardial biopsy were performed in 42 patients with dilated cardiomyopathy and a short-term history of heart failure (median 2 months, interquartile range 1 to 3.5). The patients were followed up for 25 ± 9 months for events. Endomyocardial biopsy revealed myocarditis in 15 subjects (36%). The sensitivity, specificity, and diagnostic accuracy of the individual CMR tissue parameters for myocardial inflammation was 40%, 96%, and 76% for early gadolinium enhancement, 87%, 44%, and 60% for late gadolinium enhancement, 47%, 89%, and 74% for pericardial effusion, and 67%, 85%, and 79% for any 2 of the criteria simultaneously, respectively. An assessment of myocardial edema on T2-weighted imaging and/or hs-cTnT assay were inadequate for the diagnosis. The extent of late gadolinium enhancement and increased hscTnT concentration were significant predictors of a composite end point of cardiac death, urgent heart transplantation, and hospitalization for worsening heart failure (hazard ratio 1.1, 95% confidence interval 1.0 to 1.2, per percentage of left ventricular mass; and hazard ratio 2.2, 95% confidence interval 1.4 to 3.5, per ln ng/L; p = 0.008 and p = 0.001, respectively). In conclusion, the results of the present study have demonstrated a modest performance for CMR and a limited use of the hs-cTnT assay in the diagnosis of inflammatory cardiomyopathy. Nonetheless, in these patients, CMR and/or hs-cTnT assessment seems to be useful for the prediction of the clinical outcome [ABSTRACT FROM AUTHOR]

Abstract: FOXP2, the first gene known to be involved in the development of speech and language, can be considered to be, a priori, a candidate gene in schizophrenia, given the mounting evidence that the underlying core deficit in this disease could be a failure of structures relevant to normal language processing. To investigate the potential link between grey matter concentration (GMC) changes in patients with schizophrenia and the FOXP2 rs2396753 polymorphism previously reported to be associated with hallucinations in schizophrenia, we analysed high-resolution anatomical magnetic resonance images of 40 genotyped patients with schizophrenia and 36 healthy controls, using optimised voxel-based morphometry (VBM). Here we show that the common SNP rs2396753 (C>A) gene variant of the FOXP2 gene has significant effects on GMC in patients with schizophrenia, within regions of the brain known to be affected by this disease. Our data suggest that GMC reductions in schizophrenia may be driven by C allele carriers of the FOXP2 gene variant. [Copyright &y& Elsevier]

Abstract: Whole-brain voxel-based morphometry (VBM) studies provide support for orbitofrontal, medial frontal as well as for dorsal cortical volumetric alteration in obsessive-compulsive disorder (OCD). However, there is still a need to replicate a priori unpredicted findings and to elucidate white matter volumetric abnormalities and relationships between grey (GM) and white (WM) matter volume and clinical characteristics of OCD. We compared GM and WM volume in a group of 14 patients with OCD and 15 healthy controls using a 3T MRI scanner and an optimized VBM protocol. Regression analysis was used to examine relationships between GM and WM volume and clinical variables. In OCD we have found total WM volume reduction and marked mediofrontal, right temporo-parieto-occipital, right precentral, left middle temporal, left cerebellar and bilateral pons and mesencephalon GM volume reduction in the voxel-based analysis (p ≤0.05, FDR corrected, extent threshold 100 voxels). Regression analysis indicated a positive relationship between left orbitofrontal GM volume and severity of obsessive-compulsive symptoms and a negative relationship between symptom severity and GM volume in supramarginal gyri. Earlier age of OCD onset and longer illness duration were associated with smaller left occipital GM and right parietal WM and with greater left medial frontal GM and left frontal WM (p ≤0.001, uncorrected, extent threshold 50 voxels). Our results confirm volumetric abnormalities in the medial frontal and dorsal cortical areas in OCD. The relationships between OCD and clinical variables provide further evidence that frontal, parietal and occipital structures play a role in the disorder. [Copyright &y& Elsevier]

Purpose: To assess the entire geometric and dosimetric (relative) uncertainties of the radiosurgery procedure with the Leksell gamma knife.Materials and methods: The entire Leksell gamma knife stereotactic radiosurgery treatment procedure was simulated with the use of a special water filled head phantom and polymer-gel dosimeter evaluated by nuclear magnetic resonance (NMR). A test vessel filled with the polymer-gel dosimeter was fixed in the head phantom. The phantom underwent stereotactic NMR imaging, treatment planning and then irradiation according to the treatment plan prepared exactly the same way as in the ordinary treatment procedure for a patient. The treatment plan was represented by one isocenter positioned approximately centrally in the head phantom. This procedure was subsequently repeated for all four collimators (4, 8, 14, 18 mm) used on the Leksell gamma knife. Evaluation of dosimeters was performed on a Siemens EXPERT 1 T NMR scanner. Dose profiles in X, Y and Z axes through the ellipsoidal shaped dose distribution were obtained to compare experimental results from the irradiated phantom with the treatment planning system calculations.Results: Reasonable agreement was observed between the treatment planning system calculations of relative dose distribution and the measured data. The maximum observed deviation in the spatial position between the center of the measured and calculated dose profiles was 0.6 mm. The maximum observed difference in full width of half maximum between calculated and measured profiles was 1.2 mm.Conclusions: The use of polymer-gel dosimetry for a verification of stereotactic procedures has some unique advantages that can be summarized as follows: the dosimeter itself is tissue equivalent, three-dimensional dose distributions can be measured and the dosimeter allows simulation of the patient''s procedures without any limitations. [Copyright &y& Elsevier]