View clinical trials related to Magnetic Resonance Imaging.
Filter by:Adult soft tissue sarcomas (STS) are rare tumours with an estimated incidence averaging 5/100 000/year in Europe. The prognosis of soft tissue sarcomas is dominated by local recurrence and distant metastasis. A link seems to exist between local recurrence and overall survival. Local recurrence occurs in approximately 16-29% of STS of the limbs. A combination of resection and radiotherapy is the optimal treatment of primary tumours according to histological grade and surgical result. Modern imaging techniques such as ultrasound (US), magnetic resonance (MR) and computed tomography (CT) are normally used to rule-out a recurrence in patients operated on for STS. However, none of this technique is perfect and different advantages and drawbacks have to be considered in choosing one or another technique. In the past, US was used in tumour follow-up to detect tumour recurrences, however these studies didn't use high-resolution transducers and the timing of imaging respect to surgery was not defined. The recent advances in transducer technology improved the diagnostic capabilities of US. For the evaluation of limbs soft-tissue masses, US is widely used as a first level modality. The reasons are that US is widely available, fast, easily repeatable and often more accessible than CT and MR Imaging. In addition, US equipped with high-frequency transducers have a spatial resolution that may be comparable or higher than that of MR Imaging and CT in the evaluation of superficial soft-tissues. US and MR Imaging are often not able to differentiate benign from malignant tumours, therefore several lesions detected with US or MR Imaging warrant biopsy. The clinical practice guidelines of the ESMO (European Society of Medical Oncology) published in 2010 found that there are no published data to indicate the optimal routine follow-up policy of surgically treated patients with localized disease. Moreover, it has not been demonstrated that, for limb sarcomas recurrences, MR Imaging is superior and cost-effective compared to US for the assessment of the primary site. Considering that surgically treated intermediate-/high-grade patient may be followed frequently, even every 3-4 months in the first 2-3 years and considering that performing US is easier than having MR Imaging, the purpose of this study is to evaluate the diagnostic performance of US in the detection of local recurrences of adults patients with soft tissue sarcomas of the limb.
Diagnostic Magnetic Resonance (MR) imaging procedures can be stressful for children and parents. Patients must lie still during the procedure to provide diagnostic quality images. Children <7 years are often sedated or given general anesthesia (GA) for imaging procedures. The high cost of GA and its associated risks motivate the search for alternatives. The overall goal of this study is to systematically investigate whether training on the mock MR scanner reduces the need for GA during Magnetic Resonance Imaging (MRI) scans in children. 160 participants scheduled for diagnostic MRI scans at Alberta Children's Hospital (ACH) will be recruited to undergo different training methods for MRI scanning. Group 1 will be sent links to online videos about MRI, audio files with scanner noises, and a children's book about MR scans, to prepare at home. Group 2 will receive training materials and visit the ACH to review them with the research team, but will not use the mock scanner. Group 3 will receive training materials and visit the ACH for training on the mock MR scanner. Visits to the mock scanner for Group 3 will include practice lying down, staying still, wearing headphones, and watching a movie on the mirror system. During and after training sessions, the investigators will collect data on total time spent preparing (mock scanner or other), the child's feelings of stress/worry before and after visit, and head motion during mock MRI session (if applicable). Subjects will be scheduled for a clinical scan without GA and a follow-up clinical scan with GA (to be cancelled if the first scan is successful). Scan success will be determined by a radiologist. Measures of scan success, quality ratings for each scan, children's feelings of stress/worry related to the MRI, and saliva samples to measure cortisol and salivary alpha amylase, will be gathered at the clinical scan. An ANOVA will be used to compare different training groups. A clinical group of 35 neuro-oncology patients aged 3-7 years of age that undergo frequent MRI scans will also undergo staged preparation by child life specialists using the mock scanner. The age at which they are able to complete MRI without general anesthesia will be compared with a retrospective control group in the 3 years prior. Measures to be used for this group are the same (with the exception of saliva samples). T test and Kaplan- Meier analysis will be used to compare age at which MRI can be performed awake.
What is the optimal maintenance dose of remifentanil to ensure apnoea, during breath hold episodes in children having cardiac MR imaging with general anaesthesia?
Patients with suspected or proven sigmoid colon adenocarcinoma, eligible for curative treatment whose MRI can be reviewed prior to surgery and has no decision regarding radical treatment are eligible. Patient are randomised to the control arm which the standard care of preoperative CT imaging and subsequent discussion by the Multidisciplinary Team or the interventional arm which has the additional use of MRI imaging and subsequent discussion by the Multidisciplinary Team. Patients are followed up at 1 and 3 years together with QoL questionnaires.
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.
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
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.
Young women with breast cancer have an increased breast tissue density and conventional imaging tests such as mammography and breast ultrasound are less sensitive and specific for detecting breast cancer than in older breast cancer patients. Breast MRI is an emerging tool that has been proven to improve the ability to identify breast cancers by determining the extent of disease and also detect multifocal, multicentric and bilateral breast cancers. To date, the role of pre-operative breast MRI is not clearly defined. The investigators are proposing a study to evaluate the impact of preoperative breast MRI on surgical decision-making in breast cancer patients <= 50 years. This may lead to improved characterization of breast cancers in these younger patients that may ultimately result in lower local recurrence rates in the future. The additional information attained through the breast MRI may also guide the use of radiation, chemotherapy and/or hormonal therapy in these patients.
The purposes of this study is to integrate the objective tests into the subjective test, visual analog score (VAS), for evaluation and further understanding of relieving labor pain by TENS application on acupuncture points in the first stage of labor.
The purpose of this investigation is to develop improved magnetic resonance imaging (MRI) techniques and hardware for studying brain function. MRI is a diagnostic tool that provides information about brain chemistry and physiology. This study will evaluate new MRI methods for monitoring blood flow to regions of the brain in response to simple tasks. The MRI machine used in this study is more powerful than those in most hospitals, permitting a higher visual resolution. Normal healthy volunteers over 18 years old may be eligible for this study. Candidates will be screened with a medical history and questionnaire, and a neurological examination. Study participants will have a yearly MRI scan. For this procedure, the subject lies on a stretcher that is moved into a donut-shaped machine with a strong magnetic field. A lightweight circular or rectangular coil a device that improves the quality of the images may be placed on the head. The scan time varies from 20 minutes to 3 hours; most scans last between 45 and 90 minutes. During the scan, the subject may perform simple tasks, such as listening to tapes, tapping a finger, moving a hand, watching a screen, or smelling a fragrance. More complex tasks may require thinking about tones or pictures and responding to them by pressing buttons. Information from this study will be used to develop better imaging methods that will, in turn, permit a greater understanding of normal and abnormal brain behaviors.