Magnetic resonance imaging of the cardiovascular system and airway.

Cardiovascular MR imaging is unique in its ability to combine anatomic, physiologic, and functional information in a single examination. Established applications in the pediatric population include the evaluation of the child with a suspected thoracic aortic arch anomaly, vascular compression of the airway, coarctation of the aorta, pulmonary arterial and venous abnormalities, and cardiac or paracardiac masses. The increasing availability of radiologists with the knowledge and commitment to cardiac imaging will allow this exciting technique to thrive in the future, to the benefit of our patients.

Small bowel obstruction in rats: diagnostic accuracy of sonography versus radiography.

Our purposes were to determine whether sonography can distinguish between obstructed and nonobstructed rats and to compare the diagnostic accuracy of sonography and radiography in the diagnosis of small bowel obstruction. Nonstrangulating small bowel obstruction was created in 19 rats; sham laparotomies were performed in 18 controls. Serial radiographs and sonograms, including duplex Doppler sonography, were obtained. Bowel diameter and bowel wall thickness were evaluated retrospectively. Bowel diameter, bowel wall thickness, and resistive indices increased in the animals with obstruction; controls remained unchanged (P = 0.002). Sonography demonstrated a significantly higher diagnostic accuracy than radiography at 24 hours and beyond (P = 0.023). Ultrasonography is sensitive and more accurate than radiography in diagnosing small bowel obstruction using objective criteria in the animal model.

Characterization of posttranslational modifications in neuron-specific class III beta-tubulin by mass spectrometry.

Class III beta-tubulin, isolated from adult bovine brain, is resolved into at least seven charge variants on isoelectric focusing gels. To identify the posttranslational modifications responsible for this heterogeneity, a mixture of brain tubulins was treated with cyanogen bromide and the C-terminal fragments from the class III beta-tubulin isoforms were then isolated by binding them to the monoclonal antibody TuJ1. Combined use of tandem mass spectrometry and both subtractive and automated Edman degradation chemistry on the isolated peptides indicates that many of the isoforms differ by phosphorylation at Ser-444 plus attachment of one to six glutamic acid molecules to the side chain of the first glutamate residue, Glu-438, in the C-terminal sequence Tyr-Glu-Asp-Asp-Glu-Glu-Glu-Ser-glu-Ala-Gln-Gly-Pro-Lys.

Evaluation of suspected appendicitis in children and young adults: helical CT.

PURPOSE: To evaluate the accuracy of helical computed tomography (CT) for the diagnosis of appendicitis in children and to assess the utility of CT in establishing alternative diagnoses. MATERIALS AND METHODS: The medical records of 154 children (median age, 12 years; age range, 1-20 years) who were suspected to have appendicitis and who underwent CT were reviewed. The gastrointestinal tract was opacified in 151 of 154 patients: Only orally administered contrast material was used in 126 patients; only rectally administered contrast material, in 21 patients; and both oral and rectal contrast material, in four patients. CT findings were correlated with surgical and histopathologic findings or with clinical follow-up findings. RESULTS: Sixty-four CT scans were interpreted as positive for appendicitis and included 58 true-positive and six false-positive scans. Ninety scans were interpreted as negative and included 87 true-negative and three false-negative scans. CT had a sensitivity of 95% and a specificity of 94% for the diagnosis of appendicitis. In addition, in 32 (34%) of 93 patients without appendicitis, an alternative diagnosis was established on the basis of CT findings. CONCLUSION: Helical CT is useful in a pediatric population to diagnose or exclude appendicitis and to establish an alternative diagnosis.

Imaging evaluation of suspected appendicitis in a pediatric population: effectiveness of sonography versus CT.

OBJECTIVE: The purpose of this study was to compare the diagnostic accuracy of graded compression sonography with that of helical CT for the diagnosis of appendicitis in a pediatric and young adult population. SUBJECTS AND METHODS: Between June 1996 and April 1999, 386 pediatric and young adult patients with suspected appendicitis were examined using sonography, CT, or both: 233 underwent sonography only, 71 underwent CT only, and 82 underwent sonography and CT. All sonograms and CT scans were prospectively interpreted as showing positive or negative findings for appendicitis by one of six pediatric radiologists. CT and sonographic findings were correlated with surgical and histopathologic findings or findings at clinical follow-up. RESULTS: Helical CT had a significantly higher sensitivity (95% versus 78%, p = 0.009) and accuracy (94% versus 89%, p = 0.05) than graded compression sonography for the diagnosis of appendicitis in children, adolescents, and young adults. The specificity of both techniques was 93%. Twenty of 82 patients who underwent both sonography and CT had discordance between the findings of the two examinations. The CT results were correct in a significantly greater number of patients with discordant examinations (17/20 patients [85%]). CONCLUSION: Helical CT has a significantly higher sensitivity and accuracy than graded compression sonography for the diagnosis of appendicitis in a pediatric and young adult population, particularly in children more than 10 years old.