Dermatomyositis: correlative MR imaging and P-31 MR spectroscopy for quantitative characterization of inflammatory disease.

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.

Computed tomography and magnetic resonance imaging of the acute abdomen.

CT is a noninvasive investigation that in many instances is more sensitive in elucidating intra-abdominal and retroperitoneal disease than is conventional radiography. With modern scanners, the procedure is rapid and efficient and suitable for the most severely ill and infirm. The scans are easily interpretable, and the anatomic and morphologic depiction of disease is readily understood by those with surgical training. Information regarding the state of the bowel wall, mesentery, and intraperitoneal and retroperitoneal structures is displayed in greater detail than by any other diagnostic imaging modality. The use of intravenous contrast medium is rarely essential. The concentration of iodinated contrast needed for opacification of the bowel is no greater than 2 per cent to 5 per cent and will not complicate bowel surgery, as would standard upper gastrointestinal or barium enema studies. Abscess, free air, calcium, and intraperitoneal fluid are very sensitively detected. CT is extremely useful in aiding surgical decision making in the acute abdomen and is complementary to or has replaced conventional studies.

Paramagnetic contrast agents in magnetic resonance imaging: research at Vanderbilt University.

Experimental studies in animals have demonstrated the application of particulate and chelated paramagnetic oral contrast agents in magnetic resonance imaging (at 0.5 tesla). The ability of a soluble paramagnetic species, ferrous gluconate, to improve imaging studies of the pancreas presently is being evaluated in clinical trials. Two paramagnetic metal ion chelates, Cr EDTA and Gd DTPA, have been evaluated extensively as potential intravascular contrast agents. Renal function, tissue vascularity, abnormalities of the blood-brain barrier, and infarction of myocardial tissue may all be assessed with IV contrast enhanced magnetic resonance imaging. The contrast materials tested all represent first generation compounds. Improved relaxation characteristics, toxicity, distribution, and flexibility will result from development of second generation agents, primarily within the particulate and chelate classes.

Comparison of ventricular enlargement and radiopharmaceutical retention: a cisternographic-pneumoencephalographic comparison.

The cisternograms and pneumoencephalograms of 58 patients with suspected "normal pressure" hydrocephalus were correlated and the relationship of ventricular radiopharmaceutical entry and stasis to ventricular size was analyzed. It was found that radiopharmaceutical entry relates directly to ventricular size, stasis occurring only in markedly enlarged ventricles. Cerebrospinal fluid imaging alone is a highly reliable diagnostic study only if patients exhibit the characteristic cisternographic patterns of normal pressure hydrocephalus. In those who do not, pneumoencephalography and cisternography are valuable complementary studies which can also be used to identify primary cortical atrophy.