Analysis of the intercondylar notch by computed tomography

The purposes of this study were to document the dimensions and configuration of the intercondylar notch in the normal knee; to compare normal knee intercondylar notches to those of knees with unilateral and bilateral ACL tears to determine if there is a relationship between intercondylar notch stenosis and ACL tears; and to determine if generalized ligamentous laxity is associated with intercondylar notch stenosis and ACL tears. Three groups were compared: Group I, bilateral ACL tears; Group II, unilateral tears; and Group III, normal knees. Notch dimensions were computer-generated from CT scans. All patients were examined for ligamentous laxity. Statistically significant differences were found between normal and ACL-injured knees in regard to opening notch angle, ratio of notch width at two-thirds of the notch length to condylar width, and ratio of maximum notch width to condylar width, suggesting a significant association between anterior outlet stenosis and unilateral and bilateral ACL tears. The shapes of the notches were determined from tracings of the distal CT scan. Shapes ranged from inverted U to cresting wave. Narrow notches tended to be waveshaped, but more study is needed in this area. Notch-plasty is recommended for those with documented stenosis. The ratio of maximum notch width at two-thirds of the notch height to maximum condyle width should not be much less than 0.2, and the opening notch angle should be at least 50 degrees.     

Tumor vascular signals in renal masses: detection with Doppler US

The vascularity of 49 renal masses (26 malignant and 23 benign lesions) was investigated with duplex Doppler ultrasound. Doppler signals obtained at the margins of renal masses were defined as "tumor signals" when the Doppler-shifted frequency of the lesion exceeded the frequency shift in the ipsilateral main renal artery. These exceeded 2.5 kHz with a 3-MHz insonating frequency. Among the 26 renal masses that subsequently proved to be malignant, tumor signals were obtained in 15 of 18 (83%) untreated renal cell carcinomas, in three of four Wilms tumors, and in two patients with metastases to the kidney, but not in the one patient with lymphoma. None of the 23 benign renal masses demonstrated tumor signals. Tumor vascularity in malignant lesions gives rise to abnormal, high-velocity, Doppler-shifted signals that can help in the differential diagnosis of renal masses.     

Sonography of acute appendicitis in childhood: perforation versus nonperforation.

We evaluated the sonographic findings in 133 consecutive children referred for suspected appendicitis. Fifty-eight of these patients (44%) ultimately underwent surgery, with 54 of these proved to have acute appendicitis. Thirty-one (58%) of the 54 had nonperforated appendicitis, and 23 (43%) had evidence of perforation. Previously described sonographic findings that have been employed in the diagnosis of appendicitis were evaluated, with the presence or absence of these findings being compared in patients with non-perforated and perforated appendicitis. In those patients who did not undergo surgery, the following findings were documented and compared to the findings in patients with proved appendicitis: (1) an identifiable appendix and its sonographic characteristics, (2) fluid localized to the right peritoneal reflection or periappendiceal region, or both, (3) free pelvic fluid, and (4) right lower quadrant adenopathy. Our results suggest that high-resolution, real-time sonography, using graded compression, is very sensitive in the identification of acute nonperforated appendicitis. Perforated appendicitis, however, can be a more difficult diagnosis because the appendix frequently decompresses with perforation and yet may not "wall off" or form a well-defined abscess. As a result, the appendix can be very difficult to identify.     

T cell-mediated immunity in the lung: a Cryptococcus neoformans pulmonary infection model using SCID and athymic nude mice.

T cells are important in systemic anticryptococcal defenses, but a role in controlling an initial pulmonary infection has not been demonstrated. A murine model with intratracheal inoculation was developed to study the acquisition and expression of pulmonary T cell-mediated immunity against Cryptococcus neoformans. Infections with four strains of C. neoformans (305, 68A, 613D, and 52D) in two strains of mice (BALB/c and C57BL/6) were examined. Unencapsulated strain 305 and slowly growing strain 68A were readily controlled apparently by nonimmune pulmonary defenses, and no extrapulmonary dissemination was detected. Strain 613D grew progressively in the lungs and disseminated to the brain and spleen. Strain 52D initially grew rapidly in the lungs and disseminated to the spleen, but a clearance mechanism developed in the lungs after day 7 postinfection and in the spleen after day 28. SCID and athymic nude mice were unable to clear a strain 52D pulmonary infection, and a lethal disseminated infection occurred. Pulmonary clearance could be adoptively transferred into SCID mice infected with strain 52D by use of immune T cells from the spleen and lungs and hilar lymph nodes of infected immunocompetent donors. Furthermore, pulmonary clearance was almost 100-fold better in SCID mice that received immune T cells from the lungs and hilar lymph nodes than in those that received immune T cells from the spleen, even though equivalent levels of delayed-type hypersensitivity were transferred by both cell populations. These adoptive transfer studies suggested that the lung and hilar lymph node T cells from immune animals either are enriched in such a way as to mediate protective immunity or home to the lungs better than do splenic T cells.