Magnetic resonance imaging of the shoulder

MRI has rapidly become a commonly used technique for evaluation of the shoulder. It provides a wealth of information regarding the entire shoulder girdle, and it is the most accurate noninvasive method available for imaging the rotator cuff. There have been numerous technical improvements in MRI in the relatively short time that clinical MRI has been in existence. Further refinements in design, new imaging sequences, and additional clinical experience should help to increase the accuracy and flexibility of this imaging modality.     

Magnetic resonance imaging of the wrist

MR imaging of the wrist has the unique capability of simultaneously demonstrating bone and soft tissue structures. Its exquisite sensitivity for detecting bone marrow edema makes it and ideal screening tool for diagnosing radiographically occult osseous injuries and areas of AVN. This, together with its ability to provide a comprehensive, non-invasive assessment of the ligaments, tendons, nerves, and components of the TFC make MRI a very powerful tool for evaluating patients with wrist pain of uncertain etiology. Its exact role in the work-up of these patients has not been entirely established, but with further advances in technology and the radiologist's understanding of wrist anatomy and pathology, MRI is assuming a more central role in this clinical setting.     

Magnetic resonance imaging]

During the last ten years substantial improvement of hardware and software used for the construction of MRI scanners has made available MRI sequences with high temporal and spatial image resolution. Therefore, MR imaging has become an excellent tool and in certain cases the gold standard for the evaluation of cardiovascular diseases. Primary indications for cardiovascular MRI include the assessment of aortic diseases, the arrhythmogenic right ventricle, surgically corrected congenital heart diseases, pericardial disease, intra- and paracardiac tumors and quantification of ventricular function and volumes and myocardial mass. Secondary indications include hypertrophic and dilative cardiomyopathies, valvular and ischemic heart disease. MRI is a totally noninvasive diagnostic technique which is safe and without known harmful potential to biological tissue. The wide diagnostic spectrum providing anatomical, geometrical functional and biochemical information cannot be accomplished by any other diagnostic method.     

Magnetic resonance imaging arthrography of the ankle

Magnetic resonance imaging (MRI) arthrography of the ankle is a useful diagnostic modality in the detection and staging of lateral ankle ligament tears, particularly in patients who fail to respond to conservative management. MRI arthrography also may be helpful in determining the extent of ligamentous injury in professional athletes, for whom immediate surgical repair may be the initial treatment. Preoperative planning is optimized with MRI arthrography. Frequently, alternative diagnoses may be made for conditions that can simulate lateral ligamentous injury, thus obviating the need for diagnostic arthroscopy.     

Magnetic resonance imaging of the female pelvis

Evaluation of pelvic pathology is an important part of most radiology practices. Magnetic resonance imaging (MRI) has proven itself to be a useful and cost-effective method in evaluating many of these diseases. This article reviews appropriate MR imaging techniques and findings of common gynecologic disorders. Uterine pathology is categorized into congenital anomalies, benign lesions (leiomyomas, adenomyosis, endometrial polyps, and nabothian cysts), and malignancies (endometrial and cervical carcinoma). Adnexal pathology reviewed includes endometriosis, polycystic ovaries, teratomas, and benign and malignant ovarian epithelial tumors.     

Magnetic resonance imaging of the olfactory apparatus

The magnetic resonance imaging visualization of the olfactory apparatus is reported in this article. We used a superconductor-type magnetic resonance device (Siemens Magnetom H15 (1.5 T) with a surface coil. The subjects were patients with posttraumatic anosmia. The olfactory bulbs were clearly visualized in the frontal plane magnetic resonance images, the olfactory bulbs and the foramina of the cribriform plate were visualized in the sagittal section, and the olfactory bulbs, tracts, and other structures were visualized in the coronal sections. The olfactory nerves could not be seen.     

Magnetic resonance imaging of acute stroke

In the investigation of ischemic stroke, conventional structural magnetic resonance (MR) techniques (e.g., T1-weighted imaging, T2-weighted imaging, and proton density-weighted imaging) are valuable for the assessment of infarct extent and location beyond the first 12 to 24 hours after onset, and can be combined with MR angiography to noninvasively assess the intracranial and extracranial vasculature. However, during the critical first 6 to 12 hours, the probable period of greatest therapeutic opportunity, these methods do not adequately assess the extent and severity of ischemia. Recent developments in functional MR imaging are showing great promise for the detection of developing focal cerebral ischemic lesions within the first hours. These include (1) diffusion-weighted imaging, which provides physiologic information about the self-diffusion of water, thereby detecting one of the first elements in the pathophysiologic cascade leading to ischemic injury; and (2) perfusion imaging. The detection of acute intraparenchymal hemorrhagic stroke by susceptibility weighted MR has also been reported. In combination with MR angiography, these methods may allow the detection of the site, extent, mechanism, and tissue viability of acute stroke lesions in one imaging study. Imaging of cerebral metabolites with MR spectroscopy along with diffusion-weighted imaging and perfusion imaging may also provide new insights into ischemic stroke pathophysiology. In light of these advances in structural and functional MR, their potential uses in the study of the cerebral ischemic pathophysiology and in clinical practice are described, along with their advantages and limitations.     

Magnetic resonance imaging of disseminated sclerosis

Multiple sclerosis is a chronic demyelinating disease. Paraclinical examinations may contribute to the diagnosis of multiple sclerosis. Magnetic resonance imaging (MRI) has a very high sensitivity concerning multiple sclerosis, and has made it possible to visualize multiple sclerosis plaques in vivo, to follow each plaque over the course of time and in this way to obtain information about the pathogenesis. MRI has shown that the size of plaques may vary considerably, and that plaques are dynamic structures with the ability to change in size over few weeks. By using MRI and the contrast agent Gadolinium-DTPA, it is possible to distinguish a newly developed plaque from an older one. Therefore, MRI has become an important examination in therapeutic trials. Just now, MRI with Gadolinium-DTPA is being used to evaluate the efficacy of plasmapheresis and immunoglobulin treatment in a joint study between Rigshospitalet and Hvidovre Hospital.     

Magnetic resonance imaging of primary cardiomyopathies

Cardiomyopathies are diseases of the myocardium of unknown etiology associated with cardiac dysfunction. On the grounds of their morphology and pathophysiology, primary or idiopathic cardiomyopathies may be classified into a number of disorders; namely, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy, and restrictive cardiomyopathy. The term "secondary cardiomyopathies" is reserved to specific heart muscle diseases clinically very similar to primary cardiomyopathies. Cardiac magnetic resonance imaging has long been used to study cardiac morphology and, more recently, to assess blood flow, perfusion, and contractile function. The emerging role of magnetic resonance imaging for the understanding and treatment of primary cardiomyopathies cannot be underestimated. From a clinical point of view, an examination based on a single, efficient, and noninvasive MR study focusing on the clinically relevant features of cardiomyopathies is an objective and reproducible means for diagnosing and monitoring hypertrophic, arrhythmogenic, dilated, and restrictive cardiomyopathies.     

Magnetic resonance imaging of elephantiasis neuromatosa

We present the case of a 43-year-old man with neurofibromatosis type 1 who developed elephantiasis neuromatosa of his left leg. The gross limb enlargement was extremely disfiguring, and resulted in such severe disability that he was only able to walk a very short distance using crutches. Previous debulking procedures had resulted in massive blood loss, and prior to attempting further surgical intervention MRI studies were requested. Taking advantage of the excellent tissue characterisation and multiplanar imaging capabilities of MRI, we were able to assess the extent of soft tissue and osseous involvement. The use of recently developed MR angiographic sequences enabled us to non-invasively provide detailed images to assess the relationship of the lesions to the major vessels, as well as the vascular supply and angiographic features of the lesions themselves. This article describes our MRI-based findings, which precluded debulking surgery in this unusual manifestation of neurofibromatosis.     

Magnetic resonance imaging of thyroid swellings

The preoperative diagnosis of some thyroid neoplasms remains difficult even with the routine use of fine-needle aspiration cytology. The potential of nuclear magnetic resonance imaging (MRI) to discriminate between different thyroid pathologies was explored prospectively and compared with the final pathology in a series of 37 patients. MRI yielded high-quality images of the thyroid swelling but did not provide additional information to differentiate benign from neoplastic lesions. MRI does not contribute to the routine management of thyroid swellings.     

Magnetic resonance imaging of intracerebral hemorrhage

Computerized tomography (CT) followed with magnetic resonance imaging (MRI) several years later enabled first the direct visualization of extravascular blood and products of it's degradation. Protein component of hemoglobin is from over 90% responsible for the hyperdensity of CT image in case of a hemorrhage, whereas paramagnetic properties of hemoglobin derivates are responsible for signal changes in MRI. CT is capable to diagnose accurately just an acute hemorrhage. It changes towards hypodensity in 3 weeks with posthemorrhagic pseudocyst as a final result that has rather low specificity. Differentiation from contusion, ischemic lesion or even astrocytoma may be difficult. CT has thus "short memory" for hemorrhage. MRI can differentiate 5 stages of hemorrhage according to the time schedule: hyperacute, acute, subacute stage I, subacute stage II and chronic. Sequel of a hemorrhage is detectable even years after the hemorrhagic event. The development of intracranial hemorrhage in daily routine MR imaging is described and documented to serve as a guide of model situation for the use of physician.     

Magnetic resonance imaging of seronegative sacroiliitis

A total of 27 patients with advanced previously untreated non-small-cell lung cancer were treated with paclitaxel and ifosfamide. The starting dose of paclitaxel was 175 mg/m2 given for 3 h by intravenous infusion on day 1. Ifosfamide 4 g/m2 was given for 4 h by intravenous infusion on day 2. Dosage of the two drugs was modified according to nadir white blood count after each cycle. Involved in the treatment were 17 males and 10 female patients. The median age was 61 years (range 47-71 years) and the median Karnofsky performance status was 70% (range 60-90%), 13 cases were stage IIIb and 14 cases were stage IV. One case was not evaluable due to lost follow-up after a single dose of chemotherapy. There were five cases not determined due to a timing error. Of 21 evaluable cases, eight achieved partial response (PR 38%, confidence interval 18.1-61.5%), seven achieved stable disease, two had a minor response. The median survival time of the whole group was 255 days (range from 38 to 567 days). The major toxicities were myalgia; arthralgia and neuropathies. Throughout the study, only three cases (15%) were treated at dose level 0. After the first cycle, 18 cases were treated at dose level 1, after a second cycle, 13 cases were treated at dose level 2. Three cases with grade 3 leukopenia were seen at dose level 0. At dose level 1, two cases had grade 3 leukopenia. At dose level 2, four episodes of grade 3 leukopenia were noted. It is concluded that paclitaxel can be combined safely with ifosfamide at these dosage levels. The response rates were comparable to the other chemotherapy combination in advanced non-small-cell lung cancer. The survival results were acceptable and comparable to the cisplatin-containing regimen. This study indicates that combinations of paclitaxel and/or ifosfamide with other agents, such as gemcitabine and vinorelbine, should be explored.     

Magnetic resonance imaging of brain death

The db/db mutant mouse is a rodent model of genetic diabetes that develops renal glomerular lesions with striking mesangial matrix accumulation by the age of 16 weeks, after 8-10 weeks of sustained hyperglycemia. However, abnormalities in renal function that antedate or accompany the appearance of these pathologic changes, which resemble those found in human diabetes, have not been delineated. We therefore examined renal function in young db/ db mice and their nondiabetic db/m littermates from the age of 8 through 15 weeks. Serum creatinine and blood urea nitrogen concentrations at the onset of diabetes in db/db mice did not differ significantly from mean concentrations in db/m controls. An elevated creatinine clearance, due in large part to increased body weight, and increased urinary albumin excretion were observed in db/db compared with db/m mice soon after establishment of sustained hyperglycemia. A relative reduction in creatinine clearance was demonstrable in db/db mice at the age of 15 weeks, coincident with the appearance of overt compromise in renal function manifested by frank increases in the serum creatinine and blood urea nitrogen. The findings indicate that the well-documented glomerular pathology in db/db mice is accompanied by definable alterations in renal function, which are similar in chronology and nature to those found in human diabetes.     

Magnetic resonance imaging of the UroLume urethral stent

We discuss the use of magnetic resonance imaging of the pelvis in a patient with the UroLume urethral stent. This case demonstrates that magnetic resonance imaging is a safe and effective modality for imaging tissue surrounding the stent.