View clinical trials related to Magnetic Resonance Imaging.
Filter by:The Philips 3T imager installed on the Pavillon Baudot site is an imager dedicated solely to research. It is not located in hospital premises but in INSERM premises for which an authorization for biomedical research has been granted. This equipment is part of the Technical Platform of the UMR 1214 ToNIC whose main objective is the study of the human brain and the main pathologies that affect it. MRI is an evolving technique, which is used in many research projects. Our technical platform must follow these developments and remain at the cutting edge. One of the essential services of our technical platform is to help set up research protocols and validate acquisition sequences. This development activity is therefore located upstream of research projects involving clinical or fundamental applications. The fact that we can provide our users with a regulatory framework to carry out these development tests for their Research Involving Human Subjects project is a necessity for our research support activity. This study aims to provide a generic framework to test the feasibility of MRI sequences requested within the framework of protocols, but also to optimize MRI acquisition sequences already in place, to improve image quality and reduce artifacts that can degrade the quality of the images obtained. In France, there are just over 35 centers with MRI dedicated to research and therefore with a validation protocol allowing them to validate their sequences.
To investigate the cognitive decline after standard medical treatment without stenting in Asymptomatic Intracranial Stenosis patients and the underlying neural mechanism by fMRI.
Rationale: Chordomas and chondrosarcomas located in the axial skeleton are malignant neoplasms of bone. These tumors share the same clinical challenges, as the effect of the disease is more a function of their local aggressiveness than their tendency to metastasize (20% metastasize). The local aggressive behavior can cause debilitating morbidity and mortality by destruction of nearby located critical neurovascular structures. Imaging has, in addition to histopathology, a role in diagnosis and in guiding (neo)adjuvant and definitive treatment. Despite the low sensitivity to radiotherapy, proton radiotherapy has been successfully used as an adjunct to resection or as definitive treatment for aggressive chordomas and chondrosarcomas, making it a standard indication for proton therapy in the Netherlands. Chordomas and chondrosarcomas consist, especially after previous therapy, of non-viable and viable tumor components. Identification of these viable components by functional imaging is important to determine the effect of previous therapy, as change in total tumor volume occurs more than 200 days after change of functional imaging parameters. Objective: The main objective of this study is to determine if functional MRI parameters change within 6 months, and earlier than volumetric changes after start of proton beam therapy. This would allow timely differentiation between affected and unaffected (viable) tumor components, which can be used for therapy adjustment. Secondary objectives: Determine which set of parameters (PET-CT and secondary MRI) can predict clinical outcome (tumor specific mortality, development of metastases, morbidity secondary to tumor activity and morbidity secondary to treatment); determine what type of imaging can accurately identify viable tumor nodules relative to critical anatomical structures; improving understanding of relevance of changing imaging parameters by correlating these with resected tumor. Study design: Prospective cohort study Study population: LUMC patients diagnosed with primary or recurrent chordoma or chondrosarcoma in the axial skeleton. A number of 20 new patients per year is expected. Main study parameters: Volumetric and functional MR imaging parameters including permeability parameters. Secondary parameters are generated by PET-CT (SUV, MTV and TLG), MR (perfusion, permeability and diffusion), therapy (proton beam dose mapping, surgery) and clinical outcome. End points are disease specific survival, progression free survival (including development of metastases), side effects of treatment, and functional outcome (see CRF). In patients who are treated with surgical resection following neo-adjuvant therapy, the surgical specimen will be correlated with imaging findings. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Treatment and clinical management will not be affected in this study, thus the additional burden, risks, and benefits associated with participation in this study are minimal. Two extra MRI and one PET-CT examination will be planned during proton therapy.
Diabetic pregnancies are often complicated by placental dysfunction with reduced transfer of oxygen from the mother to the fetus, which may compromise fetal growth and organ development. In diabetic pregnancies, hyperinsulinemia and hyperglycemia very often leads to fetal macrosomia. The combination of reduced placental oxygen transfer and increasing fetal demand due to fetal overgrowth may possess a particular risk of adverse pregnancy outcome. Current methods in the antenatal identification of placental dysfunction relies on estimates of fetal size and fetal wellbeing using ultrasound including Doppler flows measurements. These measurements are only indirect estimates of placental function, as no clinical method exists to assess placental function directly. In diabetic pregnancies, the estimates are further limited due to fetal overgrowth and unreliable Doppler. In addition, in diabetic pregnancies, intrauterine fetal weight estimates by ultrasound are inaccurate because of asymmetric fetal growth. Therefore, new accurate methods to assess placental function, fetal oxygenation and fetal growth in this particular group of high-risk pregnancies is highly needed. Early and precise identification of pathology in diabetes pregnancy may lead to an improved outcome in the offspring, as precise identification of pathology facilitates important obstetric decisions in regards to maternal antidiabetic treatment and timing of delivery. Resent research indicates that MRI is useful for this purpose. It is well described, that preeclampsia is associated with an increased maternal risk of cardiovascular disease later in life. Recent studies suggest, that pregestational subclinical cardiovascular dysfunction, in particular left ventricular dysfunction, may increase the risk of preeclampsia and fetal growth restriction during pregnancy. Cardiac MRI is a sensitive method to detect subclinical maternal cardiac dysfunction, which may be used in identification of high-risk pregnancies. In addition, the longitudinal design of this study allows for the investigation of cardiovascular changes during pregnancies in normal pregnancies and pregnancies complicated by diabetes. The overall aim of this study is to improve the antenatal fetal and maternal monitoring in diabetes pregnancies. Early and precise identification of pregnancy pathology provides a better basis for important obstetric decisions regarding antidiabetic treatment, monitoring intervals and timing of delivery, which leads to a better outcome for the mother and offspring. Hypothesis Project A: Placental function and fetal oxygenation in diabetic pregnancies estimated by T2* weighted placental and fetal MRI Aim: To investigate placental function and fetal oxygenation by longitudinal T2* weighted placental MRI and the association with pregnancy complications. Hypothesis: - Diabetic pregnancies are characterized by placental hypoxia (low T2* value) - Diabetic pregnancies are characterized by fetal hypoxia (low T2* value) - Fetal and placental hypoxia is a risk factor of placental related complications in pregnancy such as low birth weight, preterm delivery, acute cesarean sections and preeclampsia. Project B: Fetal growth and the growth of selected fetal organs in diabetic pregnancies estimated by longitudinal MRI volumetry Aim: To investigate growth velocity of the fetus and selected fetal organs and the correlation with pregnancy complications. Hypothesis: - Diabetic pregnancies are characterized by accelerated fetal growth in the third trimester - Diabetic pregnancies are characterized by asymmetric growth (reduced brain/liver-volume ratio) - Abnormal fetal growth is associated with dysregulated maternal diabetes. - Abnormal fetal growth is a risk factor of pregnancy complications such as; macrosomia, preterm delivery and acute cesarean sections. Project C: Maternal cardiac function in diabetic pregnancies estimated by MRI Aim: To investigate maternal cardiac function and the correlation with pregnancy complications such as preeclampsia and fetal growth restriction. Hypothesis: - Maternal cardiac function is altered in diabetes pregnancies when compared to normal pregnancies. - Impaired cardiac function (left ventricular dysfunction) is a risk factor of preeclampsia and fetal growth restriction.
1. Normal diet：Starting from May 20, 2018, the subjects will eat a normal diet for 4 days, with no restriction on calories and food types. The subjects are required to record their daily diet and dietary intake of calories. 2. Fast diet of High control ：From May 24, 2018, the method of fast diet was adopted on alternate days. According to the dietary records of normal diet, the normal caloric intake of each subject was calculated. Fast diet was carried out according to 2/3, 1/2, 1/3 and 1/4 of the original normal caloric intake.Each caloric stage last for 4 days, and the total cycle of fast diet was 31 days. 3. Fast diet of Low control ：After the intervention of fast diet of high control, the subjects were allowed to continue the diet fast diet every other day. It was suggested that the daily caloric intake was 600kal/ day for males and 500kal/ day for females.
Magnetic resonance imaging (MRI) is a diagnostic tool in medicine that generates high quality images of the human body without the use of x-rays. Volunteers will be asked to participate in a study to evaluate improved MRI hardware that can be used to enhance the ability of MRI as a diagnostic tool. Specifically, this hardware is designed to acquire high quality images of the brain. This MRI hardware will eventually be integrated into a positron emission tomography (PET) system, which will be able to detect trace amounts of brain disease and/or brain function simultaneously with MRI. The combined system is known as a PET/MRI. For the purposes of this test, the investigators are just evaluating the MRI hardware, which will be installed in a plastic mockup of the PET system.
The investigators hypothesize that preventive VT substrate ablation in patients with chronic ICM, previously selected based on imaging criteria (BZC mass) for their likely high arrhythmic risk, is safe and effective in preventing clinical VT events.
Up to now, multiplanar reconstruction (MPR) has been widely used to detect the neurovascular compressions (NVC) on the patients with hemifacial spasm (HFS). However, due to lack of stereoscopic vision, this traditional method sometimes can not meet the requirement on identifying the details of NVC, especially when the aberrant vessels turn out to be veins not arteries. The three dimensional analytic techniques, such as curved planar reconstruction (CPR) and magnetic resonance virtual endoscopy (MRVE), may be helpful to improve the sensitivity and specificity on the demonstration of NVC with stereo and dynamic views, so as to assist the design of the surgical plan. Furthermore, the frequent finding of NVC on MRI studies of asymptomatic patients incited the creation of several strict criteria for the imaging diagnosis of NVC: the vessel must cross perpendicular to the long axis of the nerve, the nerve must be deviated or indented at the root entry zoon (REZ) by the vessel. Alternatively, morphological measurement of the nerve may correlate with the severity of facial spasm due to atrophy of the nerve in most cases of HFS, and is likely secondary to the micro-structural abnormalities, such as axonal loss, demyelination, collagen deposition, etc. In this study, cross-sectional area (CSA) and volume (V) of the cisternal facial nerve will be assessed to determine whether it can be a useful biomarker for predicting the degree of HFS.
Positron Emission Tomography (PET) provides a valuable tool for the diagnosis and staging of liver fibrosis. Activation of hepatic stellate cell (HSC) is a key link in the pathophysiological development of liver fibrosis. In human liver tissue, fibroblast activation protein (FAP) was only expressed in active HSCs and fibroblasts, but not in static HSCs. Therefore, FAP has become an excellent target for diagnosis and treatment of liver fibrosis. Recently, radionuclide-labeled fibroblast activation protein inhibitors (FAPI) as a new novel positron tracer has shown to be effective to detect various cancers. In this prospective study, the investigators will use the most advanced imaging equipments, integrated PET/MR, and PET/CT with gallium-68 (68Ga) -FAPI to image patients with or suspected of liver fibrosis, the aim is to explore the value of 68Ga-FAPI hybrid PET/MR and PET/CT in liver fibrosis.
Using Multi-tracer to early diagnosis of therapy-associated cardiotoxicity using multimodality PET/MRI.