View clinical trials related to Magnetic Resonance Imaging.
Filter by:A single subanesthetic dose infusion of the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine has rapid and robust antidepressant effects in patients with treatment-refractory major depressive disorder (TRD). A family history of an alcohol use disorder (Family History Positive, FHP) is one of the strongest identified predictors of an improved antidepressant response to ketamine. Like ketamine, alcohol is a functional NMDA receptor antagonist. FHP is associated with differential response to ketamine, e.g. blunted psychotomimetic side effects. One of the primary mechanistic hypotheses for ketamine's antidepressant action is the acute intrasynaptic release of glutamate from major output neurons, e.g. cortical pyramidal cells. Preliminary clinical studies have demonstrated this acute glutamate "surge" in response to subanesthetic dose ketamine. Based on these findings, the investigators hypothesize that ketamine's enhanced antidepressant efficacy in FHP TRD subjects is, at least in part, attributable to increased glutamate release relative to TRD subjects without a family history of alcohol use disorder (Family History Negative, FHN). To test this hypothesis, the investigators have designed a now two-site, open-label study of 18-55-year-old medically and neurologically healthy, currently moderately-to-severely depressed TRD patients. In total, the investigators plan to recruit 25 FHP and 25 FHN TRD subjects. All subjects must not have a lifetime substance use disorder (except nicotine or caffeine) and no lifetime history of an alcohol use disorder. The experimental portion consists of two phases. The preliminary first phase is a medication taper (if needed) and psychotropic medication-free period. The experimental second phase comprises one subanesthetic dose (0.5mg/kg x 40 minute) ketamine infusion. The ketamine infusion will occur during 7T-magnetic resonance imaging (MRI), both resting-state functional MRI (rs-fMRI) and magnetic resonance spectroscopy (MRS) to detect glutamate in the ventromedial prefrontal cortex/ventral anterior cingulate cortex (vmPFC/vACC). The primary outcome measure is group mean change in Montgomery-Åsberg Depression Rating Scale (MADRS) score from pre-ketamine infusion (baseline) to one-week post-infusion, where the investigators observed ketamine's greatest antidepressant effect in FHP TRD. Additional outcome measures are vmPFC/vACC glutamate change in response to ketamine based on family history status. In summary, this study will provide key mechanistic information on ketamine's improved antidepressant efficacy in a biologically-enriched subgroup. This will contribute to the systematic development of more efficacious, personalized treatments for major depression in an effort to reduce its enormous public health burden.
This is an open-label, multi-center study involving babies 0-2 months of age who have liver problems (pathology) and need to have their liver and possibly, the bile ducts imaged using magnetic resonance imaging and injection of a contrast agent (dye). This agent is called Eovist. It has been marketed since 2004 and used in many countries all over the world. The baby will have blood tests before and after the imaging is done to make sure that there are no unexpected findings before and after the imaging. Also 3 blood samples up to 8 hours after the injection will be obtained in order to measure how much of the dye is in the blood. The baby will have an intravenous line which can be used for the blood samples and will not need to be stick for the blood samples. Several radiologists will evaluate the images. The family doctor will be contacted to find out what was the diagnosis and treatment after the results of the MRI were known. Six months after the study, the parent(s)/legal guardian(s) will be contacted to make sure the that baby did not have any problems, especially with the skin, joints and eyes.
The application of FCH PET in breast cancer diagnosis has not been reported. We hypothesize that FCH reveals choline metabolic profiles of breast cancers, and shows the similar pathophysiological mechanism to choline on proton MRS, and our study goals are: 1. To investigate and compare the diagnostic performance of proton MRS and FCH PET for localized findings on mammography and breast ultrasound. 2. To investigate whether FCH PET findings are correlated with choline signals on proton MRS. 3. To evaluate if choline, water and lipid signals on proton MRS, FCH PET are associated with factors related to clinical outcome and prognosis- that is, molecular markers, tumor staging, histologic grade of breast cancers. 4. For localized advanced breast cancer, to investigate the treatment response to NAC using proton MRS and FCH PET, and to evaluate which modality is more sensitive. 5. To investigate the usefulness of FCH PET for whole body staging for breast cancer patients.
In this study, the investigators will develop and evaluate a novel intervention using standardized patients (SPs) -- or actors playing the roles of patients -- to enhance physicians' patient-centered counseling skills regarding two frequently overused, potentially inappropriate services in primary care: magnetic resonance imaging (MRI) for acute low back pain and bone densitometry in women at low-risk for osteoporosis. The investigators will further evaluate whether intervention effects on physician patient-centeredness generalize to counseling regarding other costly, unnecessary diagnostic tests.
The purpose of the present study is to make medically indicated state of the art/high end magnetic resonance imaging (MRI) exams available to all infants in the Cincinnati Children's Hospital Medical Center (CCHMC) Neonatal Intensive Care Unit (NICU).
Whole body MRI will be performed in patients with neurofibromatosis Type 1 PURPOSE 1: To determine the total tumor load (neurofibroma) and to diagnose plexiform neurofibromas or malignant peripheral nerve sheath tumors. All patients will be scanned two years after the baseline whole body MRI to investigate to investigate the changes of total tumor load. PURPOSE 2: added value of diffusion weighted imaging in diagnosis of high-risk neurofibromas PURPOSE 3 : to determine the apparent diffusion coefficient of the malignant nerve sheath tumors and neurofibroma. PURPOSE 4 : correlation between histopathology of the surgically resected neurofibroma/malignant nerve sheath tumors and MRI findings
The purpose of this study is to determine the clinical value of the novel MRI-techniques DWI and gadofosveset-enhanced MRI for the management of rectal cancer patients.
Purpose of the study is to look at the safety (what are the side effects) and efficacy (how well does it work) of gadobutrol when used for taking images of the brain and spine. The results of the Magnetic Resonance Imaging (MRI) will be compared to the results of images taken without contrast (gadobutrol).
Objective: In this study we will develop and apply imaging techniques to perform the first three-dimensional (3-D) measurements of brain biomechanics during mild head movement in healthy human subjects. Biomechanics is the application of mechanics, or the physical principles in action when force is applied to an object, to the anatomical structure and/or function of organisms. Such techniques will be invaluable for building computational models of brain biomechanics, understanding variability of brain biomechanics across individual characteristics, such as age and sex, and determining brain sub-structures at risk for damage when movement of the head is accelerated, such as during a traumatic event. Study Population: Measurements will be performed on 90 healthy men and women aged 18-65. Design: We will build upon the model pioneered by our collaborator, Dr. Philip Bayly. The model places a human subject in a magnetic resonance (MR) scanner with one of two head support units that allows a specific range of motion. Each head support is latched such that it can be released by the subject, and results in either a rotation of the head of approximately 30 degrees or a flexion-extension of the head of approximately 4 degrees. Although both supports are weighted so that the motion is repeatable if the subject is relaxed, the subject can easily counteract the weight. The resulting acceleration/deceleration is small (in the range of normal activities, such as turning one's head during swimming) and has been validated and used in other human investigations of brain biomechanics. The subject repeats the motion multiple times during the MR scan under their own volition and desired pace to measure motion of the head and brain. Outcome measures: This project is a pilot study evaluating the potential of extracting three-dimensional estimates of brain deformation, such as strain measurements, using MR imaging. A primary outcome of this project will be a fast MR acquisition sequence for measuring 3-D brain deformation. The sequence will be evaluated by applying the protocol to human subjects, followed by preliminary quantification of the reproducibility and stability of deformation measurements.
The main purpose of this study is to collect data on the way gadobutrol is taken into, moves around, and is eliminated from, the body of children aged 0 to less than 2 years. The study will also evaluate safety and tolerability, and efficacy of gadobutrol. A maximum total amount of approximately 5 ml of blood will be needed for these analyses which will be drawn within 2-3 days. Gadobutrol is a contrast agent used for enhancement of Magnetic Resonance Imaging (MRI), potentially allowing better visibility of tissues in the body. Children aged under 2 years scheduled for a routine contrast-enhanced MRI examination of any body region may take part in this study, in which case they will receive gadobutrol as contrast agent intravenously at the standard dose of 0.1 mmol/kg (0.1 ml/Kg) of body weight. Only subjects without renal insufficiency of any intensity (i.e. estimated Glomerular Filtration Rate <80% of age adjusted normal value calculated based on the Schwartz formula) will be included in the trial. The duration of this study as a whole is around 1 year and the total number of children to be enrolled is 50. A child will be expected to take part in the study for around 7 days.