Titel Deelnemers "Korte inhoud" "Alternative Neuropsychological and Magnetic Resonance Imaging Measures in Multiple Sclerosis: Exploring the relation between brain lesion measured by diffusion tensor magnetic resonance imaging and interhemispheric communication and processing speed in mu" "Nele Warlop" "Multiple sclerosis (MS) is a chronic neurological disease of the central nerve system that affects young adults with a higher prevalence in women (ratio 3:2). The neuropathology of the disease is characterised by demyelination of the white matter in the brain and central cord. MS may involve degeneration of white matter throughout the nervous system, with a predilection for specific target zones that includes the corpus callosum. The pathologic process may lead to motor problems, but halve of the patients has cognitive problems associated with MS. In this thesis, we focus on the cognitive problems and the relation with neuropathological brain damage. One of the brain areas preferentially involved in MS, is the corpus callosum. This brain structure is the largest white matter tract connecting both hemispheres. Research in callosotomy patients, acallosal patients and callosal section patients indicates that robust callosal damage may lead to interhemispheric transfer dysfunctions. In the first part of this thesis callosal problems in MS are explored. Damage to the corpus callosum in this patient group is subtler than in callosotomy patients. Moreover, the callosal damage strongly varies from patient to patient. In this thesis the redundancy gain paradigm, a behavioural measure to investigate interhemispheric communication is used. In this task, flashes of light are presented to the left, right or bilateral (left and right simultaneously) visual hemifield while the subject fixates to the middle of the screen. As soon as the subject detects a flash, he presses the response button with the left or right hand (detection task). An effect that is typically observed in healthy subjects is that reaction times to bilateral stimuli are faster than to unilateral stimuli. This effect is referred to as the redundancy gain effect. Previous research shows that the redundancy gain effect is enlarged in patients with callosal problems (acallosal patients or patients with callosal section). The results in this thesis show, in analogy with the results in patients with robust callosal damage, an enlarged redundancy gain effect for MS patients. These results demonstrate the sensitiveness of the redundancy gain paradigm to investigate callosal problems in MS. To explore the effect of the amount of callosal brain damage on the redundancy gain effect, the callosal damage needs to be quantified. For this purpose diffusion tensor imaging was used. With this technique, water diffusion in the white matter can be investigated. Water in the brain spreads preferentially along the direction of the axonal fibers. Intact myelin sheets are effective barriers for the water. Demyelination, an important pathological aspect of MS, leads to decreased delineation of the tracts along which the water spreads. This results in changed diffusion derived measures. Fractional anisotropy is an important diffusion derived measure for inter- and intravoxel fiber coherence. Previous research shows that fractional anisotropy is decreased in MS patients compared to healthy controls. To calculate the fractional anisotropy, diffusion measures along three directions are defined, more specific along the principal direction, along the direction of minimal diffusion and along a third Alternative Neuropsychological and MRI Measures in MS 89 Summary direction that is orthogonal to the previous two. With this information, the longitudinal and transverse diffusivity can be calculated. Longitudinal diffusivity is the diffusion eigenvalue along the principal direction, whereas the transverse diffusivity is the mean of the eigenvalues along the other two directions. Recent research shows that demyelination and axonal loss, specific for MS pathology, is characterised by increased transverse diffusivity. Hence, transverse diffusivity is a unique marker for MS. The results of this thesis confirm this and show that transverse diffusivity is significantly more increased than longitudinal diffusivity in MS patients compared to healthy matched controls. Thirdly, a correlation between the behavioural results, the redundancy gain effect, and the brain imaging measures, the diffusion derived measures, was found: the larger the transverse diffusivity, or in other words, the MS related callosal damage, the larger the redundancy gain effect in MS patients. Moreover, neither longitudinal diffusivity, nor callosal lesion load as defined on conventional T2 images were additional factors in explaining this correlation. The results of the first part of this thesis show a) that the redundancy gain paradigm is a sensitive measure to investigate callosal brain damage in MS, b) that diffusion derived parameters are subtle measures to indicate MS related brain damage and c) that a significant correlation between callosal brain damage and the redundancy gain effect could be found in MS patients. In the second part of this thesis the focus was on the relation between cerebral brain damage as defined by diffusion derived measures and information processing speed in MS. Information processing speed is a cognitive measure tested by the Paced Serial Addition Test (PASAT) and the Symbol Digit Modalities Test (SDMT), two commonly used neuropsychological tests in MS. A significant correlation between the performance on the SDMT and transverse diffusivity in the whole brain was found in MS patients, indicating that demyelination and axonal damage, characteristic for MS pathology, are important factors for explaining the slowed information processing speed in MS. No correlation was found with the performance on the PASAT, which can be explained by the weaker psychometric qualities of the PASAT compared to the SDMT. First of all, the results of this thesis corroborate the heterogeneous pathological condition in MS. Research on callosal problems in MS can not be done without considering these individual differences. Based on our results, diffusion weighted imaging seems to offer a promising technique to determine cerebral damage in MS. Transverse diffusivity, considered to be a unique benchmark of white matter demyelination as seen in MS, is of special interest. Moreover, this diffusion derived measures correlate with cognitive (dys)function in MS, a correlation not consistently found for conventional imaging (lesion load on T2 of T1 images)." "Magnetic resonance imaging: value of diffusion-weighted imaging in differentiating benign from malignant breast lesions" "Sandra Stijven, Ellen GIELEN, Charlotte Bevernage, Monique HORVATH, Liesbeth MEYLAERTS" "Objectives: Although magnetic resonance imaging (MRI) has a high sensitivity in the detection of tumours, there is still much discussion about its role in breast cancer detection. MRI is not yet routinely used to further characterize lesions in patients diagnosed with breast cancer. This study investigated the impact of preoperative MRI on the surgical treatment of women with biopsy proven breast cancer. The diagnostic value of preoperative MRI was compared with that of conventional imaging (mammography and ultrasonography), and the diffusion-weighted imaging technique was also evaluated. Study design: 40 women underwent conventional imaging and biopsy as part of the clinical workup. In addition, preoperative MRI was performed in each patient. The kinetics of contrast captation were monitored and apparent diffusion coefficients were calculated. All imaging findings were compared with the histopathologic results, which were used as the gold standard. Differences in tumour extent, as determined by ultrasonography, MRI and histopathology, were evaluated. Results: Contrast captation kinetics curves are mostly aspecific, while apparent diffusion coefficient values seem to correlate much better with tumour malignancy. MRI correlated more accurately with histopathological findings than ultrasonography and even revealed unsuspected multifocal and multicentric breast carcinoma in 20 patients (50%). The surgical plan of seven patients (18%) was changed as a result of the additional information provided by MRI. Conclusion: Diffusion-weighted imaging as a complementary tool to contrast captation kinetics and morphologic measurements may increase the specificity of MRI and help in differentiating between benign and malignant breast lesions. In addition, MRI yields more precise information than mammography and ultrasonography about the exact location, the extent, the multifocality or multicentricity of the tumour and can also detect possible additional tumours. Although MRI will never replace mammography (screening) or ultrasonography as a test for breast cancer in women with no high risk (e.g. BRCA 1 or 2 carriers), its use in a preoperative setting may allow more accurate staging of the disease, which in turn could result in a change in the treatment planning. (C) 2012 Elsevier Ireland Ltd. All rights reserved." "Effect of mechanical stress on magnetic resonance imaging of the sacroiliac joints: assessment of military recruits by magnetic resonance imaging study" "Gaëlle Varkas, Manouk de Hooge, Philippe Carron, Dirk Elewaut, van den Bosch Filip" "Is the flexion-abduction-supination magnetic resonance imaging view more accurate than standard magnetic resonance imaging in detecting distal biceps pathology?" "Eva Schenkels, Pieter Caekebeke, Linus Swinnen, Jef Peeters" "Background and hypothesis: Partial biceps tendon pathology is difficult to diagnose. The flexion-abduction-supination (FABS) magnetic resonance imaging (MRI) view has been advocated to improve the accuracy of MRI investigation. The purpose of this study was to evaluate the accuracy of the FABS view MRI in the diagnosis of distal biceps tendon pathology. Methods: The study included 50 patients with surgically confirmed distal biceps tendon pathology and 50 patients with other elbow disorders. In both groups, standard elbow MRI (retrospective review of previously obtained MRI data) was performed in half of the patients whereas FABS views MRI were obtained in the other half. These were evaluated by 2 independent musculoskeletal radiologists. The sensitivity and specificity of both MRI views were determined. Tendinosis and grade of rupture were reported from MRI and then compared with surgical findings. Results: There were no significant differences in sensitivity and specificity in detecting partial distal biceps injuries when the FABS view MRI (sensitivity, 84%; specificity, 86%) and standard MRI (sensitivity, 76%; specificity, 98%) were compared. The interobserver reliability was 92% for the FABS view MRI with biceps pathology and 68% for standard MRI. In the control group, the interobserver reliability was 88% for the FABS view MRI and 96% for standard MRI. FABS MRI was significantly better regarding grade of injury. Conclusions: No significant differences in sensitivity and specificity were found between the FABS view and standard elbow MRI in the diagnosis of partial distal biceps tendon injuries, with high sensitivity and specificity for both views. Inter-rater reliability was better for FABS views, and FABS views were significantly more accurate than surgical findings in grading the extent of pathology. (C) 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved." "Magnetic Resonance Imaging for Noninvasive Assessment of Lung Fibrosis Onset and Progression: Cross-Validation and Comparison of Different Magnetic Resonance Imaging Protocols With Micro-Computed Tomography and Histology in the Bleomycin-Induced Mouse Mod" "Greetje Vande Velde, Ellen De Langhe, Jennifer Poelmans, Tom Dresselaers, Rik Lories, Uwe Himmelreich" "Bleomycin instillation is frequently used to model lung fibrosis, although the onset and severity of pathology varies highly between mice. This makes non-invasive fibrosis detection and quantification essential to obtain a comprehensive analysis of the disease course and to validate novel therapies. Magnetic resonance imaging (MRI) of lung disease progression and therapy may provide such a sensitive in vivo readout of lung fibrosis, bypassing radiotoxicity concerns (when using micro-CT [μCT]) and elaborate invasive end point measurements (histology). We aimed to optimize and evaluate 3 different lung MRI contrast and acquisition methods to visualize disease onset and progression in the bleomycin-induced mouse model of lung fibrosis using a small-animal MRI scanner. For validation, we compared the MRI results with established μCT and histological measures of lung fibrosis." "Intracranial Vessel Wall Imaging with Magnetic Resonance Imaging: Current Techniques and Applications" "Vincent Thijs" "Vessel wall magnetic resonance imaging (VW-MRI) is a modern imaging technique with expanding applications in the characterization of intracranial vessel wall pathology. VW-MRI provides added diagnostic capacity compared with conventional luminal imaging methods. This review explores the principles of VW-MRI and typical imaging features of various vessel wall pathologies, such as atherosclerosis, dissection, and vasculitis. Radiologists should be familiar with this important imaging technique, given its increasing use and future relevance to everyday practice." "Minimal invasive imaging of the tumoral micro-environment in squamous cell carcinoma of the head and neck: value of diffusion-weighted and dynamic contrast-enhanced magnetic resonance imaging for tumour detection, regional staging and treatment follow-up" "Vincent Vandecaveye" "Het globale doel van de thesis was om de waarde te evalueren van dynamis che contrast- (DCE-MRI) en diffusiegewogen magnetische resonantie (DWI) in de karakterisatie van lymfeklieren, de differentiatie van post-radiot herapie necrose en inflammatie van tumorrecidief en de vroegtijdige voor spelling van het therapieresultaat in het spinocellulair carcinoom van h et hoofd-halsgebied. Terwijl DWI onderzocht werd voor lymfeklierstadiëring, differentiatie va n het post-radiotherapie tumorrecidief en therapiepredictie, werd voor D CE-MRI de nadruk gelegd op therapie follow-up en -predictie. Voor de pretherapeutische studie met betrekking tot lymfeklierdifferenti atie werden 33 patiënten geïncludeerd, voor wie DWI in de eerste plaats werd vergeleken met conventionele MRI. DWI, gekwantificeerd door de appa rent diffusion coefficient (ADC), toonde een significant hogere sensitiv iteit dan conventionele MRI voor de detectie van lymfeklier-metastasen ( per nekzone: 94% vs. 57%, p" "Magnetic resonance imaging in diagnosis, staging and radiotherapy planning for prostate cancer" "Pieter De Visschere, Valérie Fonteyne, Nicolaas Lumen, Gert De Meerleer" "Forensic age estimation based on development of third molars : a staging technique for magnetic resonance imaging" "Jannick De Tobel, Inès Phlypo, Steffen Fieuws, Constantinus Politis, Patrick W Thevissen" "Skeletal age estimation of living adolescents and young adults : a pilot study on conventional radiography versus magnetic resonance imaging and staging technique versus atlas method" "Heleen Coreelman, Elke Hillewig, Koenraad Verstraete, Michiel Bart de Haas, Patrick Werner Thevissen, Jannick De Tobel" "Objective: To compare conventional radiography (CR) and magnetic resonance imaging (MRI) of the left hand/ wrist and both clavicles for forensic age estimation of adolescents and young adults. Materials and Methods: CR and MRI were prospectively conducted in 108 healthy Caucasian volunteers (52 males, 56 females) aged 16 to 21 years. Skeletal development was assessed by allocating stages (wrist, clavicles) and atlas standards (hand/wrist). Inter-and intra-observer agreements were quantified using linear weighted Cohen's kappa, and descriptive statistics regarding within-stage/standard age distributions were reported.Results: Inter-and intra-observer agreements for hand/wrist CR (staging technique: 0.840-0.871 and 0.877-0.897, respectively; atlas method: 0.636-0.947 and 0.853-0.987, respectively) and MRI (staging technique: 0.890-0.932 and 0.897-0.952, respectively; atlas method: 0.854-0.941 and 0.775-0.978, respectively) were rather similar. The CR atlas method was less reproducible than the staging technique. Inter-and intraobserver agreements for clavicle CR (0.590-0.643 and 0.656-0.770, respectively) were lower than those for MRI (0.844-0.852 and 0.866-0.931, respectively). Furthermore, although shifted, wrist CR and MRI within-stage age distribution spread were similar, as were those between staging techniques and atlas methods. The possibility to apply (profound) substages to clavicle MRI rendered a more gradual increase of age distributions with increasing stages, compared to CR.Conclusions: For age estimation based on the left hand/wrist and both clavicles, reference data should be considered anatomical structure-and imaging modality-specific. Moreover, CR is adequate for hand/wrist evaluation and a wrist staging technique seems to be more useful than an atlas method. By contrast, MRI is of added value for clavicle evaluation."