Intestinal malrotation, which is defined by a congenital abnormal position of the duodenojejunal junction, may lead to midgut volvulus, a potentially life-threatening complication. An evaluation for malrotation is part of every upper gastrointestinal (GI) tract examination in pediatric patients, particularly neonates and infants. Although the diagnosis of malrotation is often straightforward, the imaging features in approximately 15% of upper GI tract examinations are equivocal and lead to a false-positive or false-negative interpretation. The clinical manifestations and upper GI tract findings of malrotation in older children and adults are less specific than are those in younger patients, and for this reason diagnosis of the condition may be more difficult. Successful differentiation between a normal variant and malrotation requires the use of optimal techniques in acquiring and interpreting the upper GI series. Familiarity with the upper GI series appearance of both normal and abnormal anatomic variants allows the radiologist to increase both diagnostic accuracy and confidence in the diagnosis of malrotation.

RATIONALE AND OBJECTIVES:The feasibility of developing an animal model to simulate radiographic features of neonatal pneumothorax was investigated, and supine computed radiography (CR) and film-screen radiography (FS) images were compared. METHODS:5-Fr pigtail catheters were inserted into the right pleural space of three New Zealand white rabbits. Two CR and two FS supine images were obtained using identical technique. After serial 4-mL injections of air, one CR and one FS supine image were obtained. The images were masked and randomized, and four radiologists reviewed the images for typical signs of pneumothorax. Chest computed tomography (CT) was performed before the injection of any air and after completion of the study. RESULTS:At zero-mL air volume, radiologists did not perceive a pneumothorax. As the air volume increased, the number of signs of a pneumothorax increased; there was no significant difference between CR and FS in the number of signs of pneumothorax detected at any volume. Chest CT confirmed that there was no unexplained air leak. The volume of air injected correlated with the calculated volume from the CT. CONCLUSIONS:This induced, volume-controlled, animal model simulated the supine radiographic features of neonatal pneumothorax.

The sensitivity of magnetic resonance (MR) imaging in the detection of avascular necrosis (AVN) of the hip and natural history of the MR findings were determined prospectively in renal allograft recipients, a group at risk for development of the disease. One hundred four patients were studied up to 24 months after transplantation. In 25 hips in 14 patients, MR findings were consistent with AVN. Pain developed in seven hips in four patients; in each hip, the MR images showed abnormality before the onset of symptoms. Plain radiographs showed abnormality in all hips that became painful; however, the plain radiographs of 17 of 18 asymptomatic hips in which MR imaging showed evidence of AVN showed no abnormality over a mean follow-up period of 16 months. All MR lesions in the symptomatic hips were larger than those in the asymptomatic cohort. MR lesions in seven hips (in five asymptomatic patients) regressed in size; in six hips, the MR images returned to normal. The findings suggest that some patients with MR evidence of AVN of the hip have spontaneous improvement.

In summary, the workshop recommended two years of research training as being essential for radiologists to acquire the skills and knowledge necessary to begin a successful research career in today's funding and academic environment. Many pathways can combine two years of research training and provide fulfillment of existing requirements to achieve specialty certification and subspecialty credentialing. Departments of radiology supporting the beginning qualified investigator should allow him or her approximately 75% research time for the first three years of the academic appointment. Departmental research time accorded faculty members may best be concentrated on a few individuals, providing them sufficient time to be competitive for peer-reviewed grants and enabling research advances to provide a solid foundation for the future of radiologic imaging.

Ninety-seven patients with recent or active variceal bleeding were randomly assigned to oral propranolol, endoscopic sclerotherapy plus oral propranolol, or transhepatic sclerotherapy plus oral propranolol. The effects of treatment on the number of units transfused, rebleeding of any magnitude, major rebleeding, and death were assessed in these patients, 82% of whom were alcoholic and 81% Child's Class C. After a minimum follow-up interval of 2 yr (range, 27-65 mo), major rebleeding rates were 65% for propranolol alone, 45% for endoscopic sclerotherapy plus propranolol, and 60% for transhepatic sclerotherapy plus propranolol. The corresponding death rates were 81% for propranolol alone, 55% for endoscopic sclerotherapy plus propranolol, and 66% for transhepatic sclerotherapy plus propranolol (p = 0.03). Thirty-three patients (34%) never received propranolol; 8 due to medical contraindications and 25 because they died or bled enough to meet the definition of treatment failure within 3 or 4 days of randomizations (no significant differences among treatment groups). Patients assigned to propranolol alone bled sooner, bled more units, and had a higher mortality rate than patients treated by endoscopic sclerotherapy plus propranolol. Patients treated with transhepatic sclerotherapy plus propranolol had intermediate results. Propranolol alone is inadequate treatment for esophageal variceal bleeding in patients with advanced liver disease.

The versatility of angiography has been expanded by the introduction of low-osmolality contrast agents; high-pressure, high-flow catheters with small outer diameters; and the use of contrast agents with low iodine concentrations. These changes have resulted in the need for a review of the physical factors that influence the flow of contrast agents through flush catheters. Various contrast agents were injected through several types of high-pressure, high-flow catheters with small outer diameters, and the flow rates were measured. Great differences in the viscosities of contrast agents resulted in proportionately smaller differences in maximum flow rates, and warming the contrast agent from room to body temperature had little effect on the maximum flow rate, except for the most viscous contrast agents. The maximum flow rates of the new low-osmolality contrast agents did not differ significantly from those of conventional ionic contrast agents of similar iodine concentration. With unheated contrast agents, iodine delivery was more rapid for contrast agents with iodine concentrations of 280-300 mg/mL.

Cranial MR images of 53 patients with neurofibromatosis were reviewed to determine the nature, extent, and number of intracranial abnormalities present. All patients studied met tentative definitions established for the diagnosis of neurofibromatosis. Twenty-three were scanned for evaluation of known CNS of cranial nerve involvement; the remainder were neurologically asymptomatic patients without suspected lesions referred for screening. Single lesions were noted in 32 patients. Multiple lesions were identified in 14 patients. Seven had normal scans. In 23 patients small focal areas of increased signal on T2-weighted scans within the brain were though to represent heterotopias. Eight patients had chiasmal gliomas and two had optic nerve gliomas. Nine patients had parenchymal gliomas, two had ischemic changes, and one had a colloid cyst. Extraaxial lesions included acoustic neuromas (five patients), meningiomas (four), trigeminal neurofibromas (one), and dysplasia of a sphenoid wing (two). Of the 30 asymptomatic patients referred for screening, lesions were found in 23. MR was found to be an excellent method of imaging known disease and of detecting lesions in asymptomatic patients. Because of the large number of asymptomatic lesions detected in this population, a screening MR study is recommended in patients with neurofibromatosis.

The diagnostic sensitivities of arteriography, intravenous (IV) Tc-99m sulfur colloid scintigraphy, and intra-arterial (IA) Tc-99m sulfur colloid scintigraphy were evaluated in a canine model of gastrointestinal bleeding. Fifteen dogs were studied at bleeding rates ranging from .4 to 1.0 ml/minute. All three studies were obtained in six of the 15 dogs. Intravenous scintigraphy was superior to angiography in two cases, inferior in three, and equal in one. No significant difference could be shown between these two tests at these bleeding rates. Intra-arterial scintigraphy was superior to angiography in four cases and equal in two (P = .06). It was superior to IV scintigraphy in five cases and inferior in one (P = .10). In this small preliminary study, IA scintigraphy appears to be superior to the other two modalities and may prove useful in the detection of acute bleeding at the time of negative arteriography, and in serial studies in patients receiving Pitressin.

Experimental allergic encephalomyelitis, a demyelinating disease with marked similarity to multiple sclerosis, was produced in two of 12 dogs. All dogs were studied with serial MR imaging. T1- and T2-weighted MR images were obtained both before and after IV Gd-DTPA. Multiple, new periventricular white matter demyelinating lesions were observed after each clinical episode of the disease. Like multiple sclerosis, the acute lesions of experimental allergic encephalomyelitis on T2-weighted MR images were indistinguishable from the older, more chronic lesions. However, after Gd-DTPA, there was bright paramagnetic enhancement of the acute lesions and, in one animal, no enhancement of the chronic lesions on T1-weighted MR images. At necropsy, the differences in the MR paramagnetic enhancement correlated well with the relative histologic age of the demyelinating lesions. Our results suggest that MR with Gd-DTPA may be used to differentiate acute, active demyelinating lesions from the more chronic, inactive lesions in this animal model.

DENHAM, J S; BECKER, G J; SIDDIQUI, A R; HOLDEN, R W; DREESEN, R G; SHIPLETT, C A; ROGERS, H P; KLATTE, E C Author Information

The blood pressure response to surgery or percutaneous transluminal angioplasty (PTA) was determined an average of 3 years after treatment. In atherosclerotic disease, 85% of patients benefited. Furthermore, the extremely low overall cure rate of 6% (4/67) suggests that renal artery stenosis due to atherosclerosis is rarely a sole cause of hypertension, but more likely is an atherosclerotic complication of essential hypertension that develops in patients who are cigarette smokers. In fibrodysplastic disease both treatments were likely to improve the blood pressure. However, surgery resulted in a 41% rate of loss of the operated kidney. The response to PTA or surgery is strongly influenced by the etiology of the lesion being treated.

The state of the art of fibrinolytic therapy is constantly changing; perhaps no other area of medicine is developing as rapidly. This paper presents the status of fibrinolytic therapy from the authors' viewpoint. Many statements are controversial. It is possible to find divergent opinions expressed by experts on almost any aspect of fibrinolysis. Objective data are rapidly accumulating, but because new substances continue to be developed, the present and future statuses of fibrinolysis remain unclear. The current results of fibrinolytic therapy are excellent but will be dwarfed by the effects of new compounds and techniques in the near future. Continued developments in this field will have a major impact on improved health care delivery.

The potential impact of local intracoronary infusion of streptokinase (SK) on vascular prostaglandin synthetic pathways was studied in a canine model. Control animals (n = 10) underwent left coronary artery (LCA) infusion of 50,000 units SK for 90 minutes; experimental animals (n = 10) underwent LCA infusion of normal saline. Plasma samples for radioimmunoassay (RIA) of prostacyclin (PGI-2) and thromboxane (TXA-2) were obtained from the coronary sinus (CS) as follows: one sample preinfusion, six samples during infusion, and three samples postinfusion in each animal. Comparisons between control and experimental plasma levels of PGI-2 and TXA-2 were made for each sampling time. The PGI-2 levels remained at or below the lower limits of detectability by RIA (the most sensitive assay available) in both control and experimental animals. TXA-2 levels were higher in experimental than in control animals at all sampling times, with the most significant differences occurring in samples 3 (after 30 minutes of infusion, .001 less than P less than .01), 4 (after 45 minutes of infusion, .05 less than P less than .10), and 5 (after 60 minutes of infusion, .02 less than P less than .05). We suggest (1) it is unlikely that any of the beneficial effects of coronary streptokinase infusions are PGI-2-mediated, (2) that the TXA-2 increases in our model may represent a pathophysiologic-biochemical correlate of previously identified morphologic evidence of endothelial damage in animals infused with fibrinolytic agents, and (3) that our findings may indicate that fibrinolytic infusions produce competing effects: lysis of thrombi and endothelial injury with TXA-2 production.(ABSTRACT TRUNCATED AT 250 WORDS)

Twenty-seven adults with extremity masses were examined by magnetic resonance imaging (MRI). In 26/27 cases, computed tomography (CT) scans were available for comparison. Imaging with multiple pulse sequences is necessary to optimize diagnosis by MRI. Advantages of MRI include direct sagittal and coronal imaging, demonstration of vessels without contrast and superior soft tissue contrast. CT better demonstrates cortical destruction and small calcifications, which may be important in some cases. For noncalcified masses without bone involvement, MRI is equivalent or superior to CT. In those cases with calcification or bone involvement, MRI plays a role complementary to CT.