Magnetic resonance spectroscopy

Life-time diagnosis of the initial pathological shifts in the organism remains an and still unsolved important problem of modern medicine. Magnetic resonance spectroscopy based on the nuclear magnetic resonance phenomenon is one of the methods which can help to solve this problem. Modern reports about the use of magnetic resonance spectroscopy in the diagnosis of various diseases are reviewed.     

Magnetic resonance cholangiography

Magnetic resonance cholangiography (MRC) can be performed with data from a routine imaging protocol, without the need for additional pulse sequences or special equipment. We studied three patients with obstructive jaundice who underwent magnetic resonance imaging (MRI) of the liver. T2-weighted fat suppressed fast spin-echo sequences were processed with a maximum intensity projection algorithm to create three-di-mensional images of the dilated portions of the biliary tree. Results were correlated with endoscopic retrograde cholangiopancreatography and computed tomography. These images compare favorably with those acquired on scanners in which special breath-holding gradient echo protocols are used.     

Magnetic resonance urography

Excellent contrast resolution and lack of ionizing radiation make magnetic resonance urography (MRU) a promising technique for noninvasively evaluating the entire urinary tract. While MRU currently lags behind CT urography (CTU) in spatial resolution and efficiency, new hardware and sequence developments have contributed to a resurgence of interest in MRU techniques. By combining unenhanced sequences with multiphase contrast-enhanced and excretory phase imaging, a comprehensive assessment of the kidneys, ureters, bladder, and surrounding structures is possible with image quality rivaling that obtained with other techniques. At the same time, formidable challenges remain to be overcome and further clinical validation is necessary before MRU can replace other forms of urography. In this article, we demonstrate the current potential of MRU to demonstrate a spectrum of urologic pathology involving the kidneys, ureters, and bladder while discussing the limitations and current status of this evolving technique.     

Magnetic resonance imaging.

Magnetic Resonance Imaging is the latest diagnostic tool to have a significant impact on patient management. Magnetic Resonance Imaging, or MRI, has been available for over six years but has only in the last 18 months become readily available to many more hospitals in Great Britain. MRI scanners have been purchased by large specialist hospitals but the arrival of mobile MRI scanners has made the technology available to smaller hospitals and groups. The impact of MRI for all clinicians and especially surgeons is great and the following text will outline the advantages of MRI and mobile MRI.     

Magnetic resonance imaging--guided breast interventions

The use of breast magnetic resonance imaging (MRI) for screening, diagnosis, staging, and management of breast cancer is rapidly increasing. MRI is highly sensitive for the detection of benign and malignant abnormalities that are occult to physical examination, ultrasound, and mammography. However, the specificity of MRI is moderate. These attributes necessitate methods for MR-guided tissue sampling to determine the histology of MRI detected lesions. This article will review appropriate peer-reviewed data and currently accepted methods for MR-guided tissue sampling. A detailed step-by-step technique for vacuum-assisted MR-guided breast biopsy is included. We also review emerging data for percutaneous and transcutaneous MR-guided breast interventions such as tissue ablation for benign and malignant disease.     

Magnetic resonance image-guided thermal ablations

Magnetic resonance imaging (MRI)-based monitoring has been shown in recent years to enhance the effectiveness of minimally or noninvasive thermal therapy techniques, such as laser, radiofrequency, microwave, ultrasound, and cryosurgery. MRI's unique soft-tissue contrast and ability to image in three dimensions and in any orientation make it extremely useful for treatment planning and probe localization. The temperature sensitivity of several intrinsic parameters enables MRI to visualize and quantify the progress of ongoing thermal treatment. MRI is sensitive to thermally induced tissue changes resulting from the therapies, giving the physician a method to determine the success or failure of the treatment. These methods of using MRI for planning, guiding, and monitoring thermal therapies are reviewed.     

Magnetic resonance images in hanging

Hanging is a devastating method of suicide and unfortunately is common in Japan. Although several CT findings of the head have been reported, there have not been any reports about magnetic resonance imaging (MRI) in hanging. We report here interesting MRI findings in a patient after hanging. A 39-year-old woman was transferred to our department after attempting suicide by hanging. Respiration had probably ceased for about three minutes but heart had not stopped when she was pulled down by her father. After her father performed cardiopulmonary resuscitation, she started to breathe immediately. She was treated conservatively in our intensive care unit for 14 days, her condition became stable. Ten days after admission, MRI demonstrated symmetrical hyperintensity on T1-weighted images and relative hyperintensity on T2 weighted images in bilateral lentiform nuclei and medial thalami. There have been several reports about characteristic MRI findings in the case of acute global cerebral ischaemia caused by severe hypoglycaemia or longstanding cardiopulmonary arrest. It was postulated that these specific findings reflected tissue degeneration, deposition of mineral substances, or lipid accumulation. These MRI findings suggest that severe acute global cerebral hypoperfusion also occurs in hanging in the same way as in long-standing cardiopulmonary arrest and that hanging has devastating sequelae.     

Magnetic resonance of vascular anomalies

More than half of the patients with vascular anomalies referred to the Vascular Anomalies Clinic at Children's Hospital, Boston, have been misdiagnosed. A major consequence of misdiagnosis is inappropriate treatment, including deferral of necessary treatment and inappropriate use of pharmacotherapy, radiation, surgery, and embolotherapy. Hemangiomas and vascular malformations are distinct categories with completely different biologic and clinical behavior, therapeutic requirements, and imaging features. This article reviews the biologic classification of vascular anomalies and corresponding MR imaging features, and presents a simplified guide to diagnosis.     

Magnetic resonance urography in children

Magnetic resonance (MR) urography is a powerful tool that fuses anatomic information with functional data in a single test without the use of ionizing radiation. This article provides an overview of the technical aspects of MR urography and common clinical applications, such as the evaluation of hydronephrosis, reflux nephropathy, and renal dysplasia.     

Magnetic resonance imaging-guided vascular interventions

Magnetic resonance imaging (MRI), which provides superior soft-tissue imaging and no known harmful effects, has the potential as an alternative modality to guide various medical interventions. This review will focus on MR-guided endovascular interventions and present its current state and future outlook. In the first technical part, enabling technologies such as developments in fast imaging, catheter devices, and visualization techniques are examined. This is followed by a clinical survey that includes proof-of-concept procedures in animals and initial experience in human subjects. In preclinical experiments, MRI has already proven to be valuable. For example, MRI has been used to guide and track targeted cell delivery into or around myocardial infarctions, to guide atrial septal puncture, and to guide the connection of portal and systemic venous circulations. Several investigational MR-guided procedures have already been reported in patients, such as MR-guided cardiac catheterization, invasive imaging of peripheral artery atheromata, selective intraarterial MR angiography, and preliminary angioplasty and stent placement. In addition, MR-assisted transjugular intrahepatic portosystemic shunt procedures in patients have been shown in a novel hybrid double-doughnut x-ray/MRI system. Numerous additional investigational human MR-guided endovascular procedures are now underway in several medical centers around the world. There are also significant hurdles: availability of clinical-grade devices, device-related safety issues, challenges to patient monitoring, and acoustic noise during imaging. The potential of endovascular interventional MRI is great because as a single modality, it combines 3-dimensional anatomic imaging, device localization, hemodynamics, tissue composition, and function.     

Magnetic resonance, an introduction

What would you explain to a patient if he/she had to undergo a magnetic resonance imagery session? Do you know if a person wearing a pacemaker can undergo an MRI? These and many other questions are answered in the following article since magnetic resonance imagery is a very useful diagnostic medium; however, it is one which not everyone has been able to get to know and use. The authors shed light on this diagnostic technique for nurses starting with its physical foundations; since knowing these aids professionals to correctly plan our treatments and improves the attention provided to patients who undergo this test. The authors also list the specific components in this device, the possible biological effects, the detractions and some basic recommendations.     

Magnetic resonance spectroscopy in migraine

31-phosphorus Magnetic Resonance Spectroscopy (MRS) is a technique developed for the non-invasive study of energy metabolism in living subjects. It determines the concentrations of high and low energy phosphates in resting and activated conditions, and of intracellular pH. 31P-MRS has been applied to the study of migraine, both during and in between attacks. Intracellular brain pH remains unchanged during the migraine attack, suggesting that ischemia does not play a relevant role in the origin of the neuro-logical signs. During and in-between attacks, migraineurs display abnormalities in energy metabolism of brain and muscle, consisting of reduced levels of phosphocreatine, reduced cellular-free energy and increased rate of ATP biosynthesis. We suggest that these abnormalities in energy metabolism predispose migraineurs to develop an attack under conditions of increased brain energy demand.