Magnetic resonance in AIDS-related encephalopathy

Fifty-eight patients with AIDS disease were studied with MR imaging in the aim of detecting the grade of brain involvement. The examinations were performed with a 1.5 Tesla magnet. Thirty-seven showed white matter lesion (63.5%), twenty-five patients showed cerebral atrophy (43%), in eight patients the MR appearance was consistent with toxoplasmosis infection (13.5%), two patients showed a linfoma (3.4%) and two patients micrococcosis (3.4%). Seventeen out of the thirty-seven patients with white matter disease showed focal well circumscribed lesion (46%), while twenty showed diffuse involvement. Between the twenty-five patients with cerebral atrophy, twelve showed a prevalence of the cortical involvement and eight a subcortical atrophy. In five patients a concomitant, cortical and subcortical atrophy was found. Between the eight patients with neurotoxolesion and two of them a widespread encephalitis picture. The MR appearance of the two limphomas was that of periventricular, space occupying, masses. In two patients with micrococcis a nodular aspect of leptomeningeal lesions was found.     

Magnetic resonance angiography in trauma

The heavy and light chain genes (mu and lambda) of the human anti-adenocarcinoma monoclonal antibody HB4C5 (MAb-C5) were cloned from the human-human hybridoma cell line HB4C5 and co-expressed in Chinese hamster ovary (CHO) and COS-7 cells. ELISA assay and the RI imaging of the cancer tissue xenografted into nude mice showed that the recombinant MAb-C5 retained the original antigen binding activity. We then replaced the IgM constant region of the MAb-C5 heavy chain gene with the human IgG1 constant region gene and co-expressed it with the light chain gene. This recombination was confirmed by a complete DNA sequencing and Western-blot analysis. Despite the fact that the DNA sequence, the expressed protein size, and the assembly of heavy and light chains were indicated to be normal, the IgG1 type MAb-C5 could not bind to the original antigen. This result suggest that this antibody alters its antigen binding property upon class-switching.     

Magnetic resonance in Hallevorden-Spatz disease

The Hallevorden-Spatz disease should be suspected in children or young people with motor, pyramidal or extrapyramidal symptomatology and deterioration of superior functions specially upon the existence of family history. Pathognomonic diagnosis may only be obtained by necropsy but magnetic resonance images, although not pathognomic, are sufficiently characteristics to strongly support the diagnosis. Four cases of Hallevorden-Spatz disease are presented with special emphasis on the MR images characteristic of this disease.     

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 in optic neuropathy

Magnetic resonance imaging has revolutionised the ability to investigate intrinsic disease of the anterior optic pathways. We review the data accumulated from this technique not only in the conditions, such as neoplasia, which have traditionally been the domain of neuroimaging, but also in inflammatory, metabolic and degenerative diseases.     

Magnetic resonance imaging in lactic acidosis

Mitochondrial defects, defects in gluconeogenesis, and biotin-responsive multiple carboxylase deficiency are disorders characterized by primary lactic acidosis. In this review, characteristic findings in magnetic resonance imaging (MRI) of the brain, as related to histopathological abnormalities, are described for the different disorders and the diagnostic value of the MRI findings is discussed. Inborn errors of metabolism with primary lactic acidosis should be considered in particular when MRI shows lesions similar to or reminiscent of effects of focal or generalized hypoxia-ischaemia, or when MRI shows signs of chronic neurodegeneration, but rarely in cases with predominantly white-matter changes.     

Magnetic resonance imaging in coccidioidal arthritis

Aortic pseudoaneurysm starts as small disruption of the aortic wall with an extravasation of blood into the mediastinum, contained only by fibrous tissue and by parietal pericardium. The most common cause of this condition is dehiscence or inflammatory processes of suture stitches after surgical interventions on aortic value or ascending sorts. Pseudoaneurysm represents about 40% of complications of cardiac surgery involving the ascending sorts. This complication occurs in about 1% of cases of aortic valve or ascending tract replacement. In this study, we evaluated, with different diagnostic techniques, 4 patients (all males, mean age 48 +/- 23 years, range 17-74) affected by aortic pseudoaneurysm occurring at different times after surgical intervention on the sorts. Clinically only 1 of the 4 patients referred chest pain. Repeated chest radiography and cardiac magnetic resonance were performed in every patient; 3 subjects were evaluated by transthoracic and transesophageal echocardiography; contrast-enhanced computed tomography was performed in 1 patients. Pseudoaneurysm diagnosis obtained by non invasive methods was later confirmed and better described by angiography. Our study demonstrated that transesophageal echocardiography and magnetic resonance are useful and reliable methods in the diagnosis of aortic pseudoaneurysm. However, in case of mediastinal he or pericardial effusion (suggestive of aortic pseudoaneurysm) by transesophageal echocardiography or magnetic resonance, angiography is necessary and may show the exact rupture site on the aortic wall. This diagnostic approach yields enough information for both diagnosis and surgical correction of this rare but high-risk pathological condition.     

Magnetic resonance tomography in neurocutaneous melanosis

Beef lean, fat, and connective tissues were inoculated with Escherichia coli O157:H7 before and after a prewashing procedure to compare the efficacy of prewashing and no prewashing on bacterial adherence and, consequently, on the removal of bacteria from the inoculated surfaces. Prewashing consisted of spraying tissues with tap water before inoculation. Final washing with disinfectant solutions compared the efficacy of several chemicals for the removal or destruction of E. coli O157:H7. The results showed that prewashing was very effective in reducing the numbers of bacterial cells on beef tissues, mainly lean tissue, in the control samples which received final washing with water. An opposite effect of prewashing was observed when disinfectant solutions were used for final washing; this may be due to dilution by water carried on the tissues after prewashing. The efficacy of chemicals was dependent on the type of exposed tissue. Hydrogen peroxide (3%) was more efficient in the removal of E. coli O157:H7 from connective tissues, with reductions greater than 4 log CFU/cm2, compared to a normally washed control (P < 0.01). Chlorhexidine (0.1%) was very efficient on fat and lean tissues, causing reductions over 5 log CFU/cm2 on not prewashed fat and lean tissues, compared to the control (P < 0.01). Acetic acid (5%) was the least effective, decreasing the number of CFU by under 1 log/cm2 as compared to the control; and no statistically significant difference was found among tissues, even though the removal of bacteria seemed less in lean tissue compared to fat or connective tissues.     

Magnetic resonance imaging in acute pyelonephritis

The diagnosis of acute pyelonephritis in children remains a clinical challenge. We assessed the feasibility of magnetic resonance imaging (MRI) detection of pyelonephritis in four pediatric patients and compared the results with renal cortical scintigraphy. MRI revealed areas of high signal intensity in the kidney that coincided with photon-deficient regions in the radionuclide scans in two children with acute pyelonephritis. These findings confirm work in experimental animals and indicate that MRI can accurately detect acute pyelonephritis in children.     

Magnetic resonance imaging in pseudotumor cerebri

Post-transplantation lymphoproliferative disorders (PTLD) are a complication of immunosuppressed transplant recipients, and their incidence is reported to be 20-120 times greater than the rate in the general population. After kidney transplantation, PTLD more likely arise within the renal transplant fossa. Radiological patterns of these forms are presented and discussed, according to a review of the literature, and illustrated by cases from our institution. Ultrasound plays an essential role in the early diagnosis of PTLD by detecting a urinary obstruction associated with adenopathy or an ill-defined mass not previously seen. However, in the case of an inconclusive US examination, CT or MRI should be performed to confirm the presence of a mass. Both techniques are useful in evaluating the extension of the process within the transplantation fossa; MRI seems more accurate and can be used for the follow-up, especially after reduction in immunosuppressive therapy without transplant removal.     

Magnetic resonance imaging in vascular dementia

This case report presents a patient who developed right shoulder pain following strenuous upper-extremity exercise. Approximately 6 weeks later his pain resolved, he noticed persistent right upper-extremity weakness. He was referred to physical therapy for evaluation and treatment. Physical therapy evaluation revealed isolated serratus anterior muscle paralysis. A long thoracic neuropathy was subsequently confirmed by electromyographic testing. The etiology, pathophysiology, and pathokinesiology of serratus anterior muscle paralysis are reviewed. A case is presented, illustrating how the clinical decision making is based on the pathokinesiology and pathophysiology. The patient was followed over the course of 17 months and has recovered full right shoulder active range of motion. His serratus anterior muscle strength has increased to Good minus, and he reports significantly improved functional use of the upper extremity.     

Magnetic resonance findings in skeletal muscle tears

Magnetic resonance (MR) images of skeletal muscle tears can clearly delineate the severity of muscle injury. Although MR imaging is seldom necessary in patients with acute muscle trauma, it can be helpful in deciding on clinical management. The two major MR findings in acute muscle tears are deformity of the muscle and the presence of abnormal signal reflecting hemorrhage and edema. In acute tears, methemoglobin within the extravascular blood causes high-signal areas on both T1- and T2-weighted images. With partial tears, the blood may dissect in a distinctive linear pattern along the muscle bundles and fibers. As healing begins, the muscle signal diminishes, first on the T1-weighted images and then on the T2-weighted images. When there is residual abnormal signal on images obtained more than several months after the injury, it is presumed to represent hemorrhage from recurrent tears. In patients with a questionable history of a remote injury, the clinical presentation may be that of persistent pain or a soft tissue mass. In these cases MR imaging may identify the cause of the pain and can exclude a neoplasm by proving that the mass is a hypertrophied or retracted muscle. Thus, MR imaging has a limited, but occasionally important role in selected patients with skeletal muscle tears.     

Magnetic resonance imaging in macromelia and macrodactyly

We report five cases presenting with soft tissue and bone overgrowth that demonstrate the ability of MRI to establish a diagnosis in the absence of specific clinical features. Disorders included macrodystrophia lipomatosa, angiolipomatosis, Klippel-Trenaunay-Weber syndrome, blue rubber bleb naevus syndrome and one case of segmental limited hypertrophy. The MRI appearances, and other radiological features of these conditions are discussed. MRI is recommended in all cases of macrodystrophy when the clinical features and plain film findings are indeterminate.     

Magnetic resonance imaging in breast cancer staging

For many solid carcinomas, high-resolution cross-sectional imaging has changed cancer staging, the evaluation of therapeutic response, the detection of recurrence, and even how therapy is selected and performed. Such imaging has not yet had similar effects on breast cancer. Evaluations of therapeutic response in breast carcinomas have been impeded by the current limited methods of evaluating breast tumor size and extent: clinical palpation, ultrasonography, and mammography. The use of magnetic resonance imaging (MRI) of the breast in the evaluation of breast tumors brings the advantages of high-resolution cross-sectional imaging to breast cancer staging and treatment evaluation and is likely to greatly enhance research efforts in this complex disease. MRI of the breast has evolved to be the most accurate noninvasive technique for local staging of breast cancer. MRI is most accurate in measuring tumor size and detecting multicentric disease. These staging characteristics affect the selection of therapy and initial determination of prognosis; therefore, MRI of the breast can change the assessment of fundamental parameters on which treatment is selected. Because clinical trials of new cancer treatments are predicated on proper and accurate characterization of the tumor, MRI also should affect how clinical trials are performed and evaluated.