Magnetic resonance (MR) imaging and phosphorus-31 MR spectroscopy were used to examine four patients with dermatomyositis and five control subjects. T2-weighted images of the thigh muscles of patients showed increased signal intensity, with focal and inhomogeneous involvement predominantly in the vastus lateralis and secondarily in the vastus intermedius and vastus medialis. T1 and T2 values of the vastus lateralis in patients were significantly higher than those of the control subjects. T1 values of the rectus femoris and biceps femoris with more generalized inflammation were moderately elevated but still significantly higher than those of the control subjects. P-31 MR spectra of the quadriceps muscles were obtained during rest, during exercise at two graded levels, and in recovery. Concentrations of adenosine triphosphate and phosphocreatine (PCr) in the diseased muscles were 30% below normal values, and the inorganic phosphate/PCr ratios were increased in the patients' muscles at rest and throughout exercise. The T1 and T2 values as well as the P-31 metabolite data correlated with symptoms and clinical assessment.
A device for gating the acquisition of magnetic resonance images with chest wall motion was developed, and the effects of respiratory gating upon image quality were studied. Images of respiratory gated examinations were compared with those of ungated examinations in 16 subjects. In a subset of four of those subjects, combined respiratory and cardiac gated images were obtained. Respiratory gating removed gross motion artifacts from magnetic resonance images of the chest and abdomen. Resolution of small normal tissue structures, such as the portal and hepatic veins, is improved. In cardiac studies, respiratory gating improved the visualization and definition of the atria and ventricles.
Currently accepted modes of clinical and radiologic evaluation were analyzed retrospectively in 55 patients with "normal-pressure" hydrocephalus on whom a cerebrospinal fluid shunting procedure was done. When applied alone, each criterion neither reliably differentiated normal-pressure hydrocephalus from cortical atrophy nor indicated in a significant number of cases which patients would benefit from shunting. Therefore, future prospective evaluations should include clinical history, physical and neurologic examination, skull radiography, echoencephalography, psychometric testing, brain scanning, lumbar puncture with cerebrospinal fluid laboratory analysis, isotope cisternography, pneumoencephalography, and constant-infusion manometric testing. Cerebral angiography may add optional support to the diagnosis of cortical atrophy but always should be done before lumbar puncture if there is evidence of intracranial mass and/or increased pressure is revealed on neurologic examination, skull radiographs, echograms, or brain scans. Patients with seizures should undergo electroencephalography. Postoperative improvement should be evaluated using serial neurologic and psychometric examinations. Echoencephalography may confirm postshunt reductions in ventricular size.
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