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.

Digital storage of echocardiograms offers superior image quality to analog storage, even with 20:1 digital compression: results of the Digital Echo Record Access Study.

A large interobserver and intraobserver variability study was performed comparing both digitally compressed and uncompressed echocardiographic images with the same images recorded onto super-VHS video-cassette tape (the current standard). In a blinded, randomized fashion, 179 observers scored the diagnostic and image quality of 20 pairs of echocardiographic loops representing various pathologic conditions. Overall, the digital images were preferred to the S-VHS images both for image quality and diagnostic content (p < 0.0001) regardless of the background or experience level of the observer. Furthermore, uncompressed digital images and those compressed by the Joint Photographic Experts Group (JPEG) algorithm at ratios of 20:1 were judged equivalent. These findings show that digital compression may be used routinely in echocardiography, resulting in improved image and diagnostic quality over present standards.

Power injection of intravenous contrast material through central venous catheters for CT: in vitro evaluation.

PURPOSE: To determine the feasibility of use of a power injector to deliver contrast material through central venous catheters for computed tomographic (CT) examinations. MATERIALS AND METHODS: Ioversol 240 and iothalamate meglumine 43% were separately injected through three 9.6-F Hickman catheters and three 10.0-F Leonard catheters with a power injector in an in vitro study. Flow rates of 1.0, 1.5, 2.0, and 2.5 mL/sec were tested. Peak pressures were mechanically recorded from two sites. A 95% prediction interval was calculated for each peak pressure, and the upper limits at the prediction interval were evaluated to determine if it was less than the recommended limit of 25 psi (175 kPa). RESULTS: Contrast medium, flow rate, and catheter type each statistically significantly affected the measured peak pressures (P = .0001). For each flow rate tested, the upper limits of the prediction interval for the peak pressure at the connection between the coiled tubing and the catheter were below the manufacturer's specified peak pressure. CONCLUSION: In vitro analysis demonstrates that power injection of intravenous contrast medium through central venous catheters does not exceed the pressure limits of these catheters at the flow rates tested. In vivo testing to evaluate the safety and efficacy of power injection through central venous catheters is necessary.

Simple steps for improving multiple-reader studies in radiology.

Multiple-reader study designs have become popular in the radiology literature. We reviewed the major papers published in the American Journal of Roentgenology in the first 4 months of each of the years 1990 and 1995. The review was restricted to prospective studies of image interpretation. In the 1990 literature, we noted eight multiple-reader and 18 single-reader studies; in contrast, in the 1995 literature, we found 29 multiple-reader and eight single-reader studies. This trend reflects an increased awareness of the importance of multiple-reader studies. We examined the Results sections of the 29 multiple-reader studies from 1995 to assess the authors' motives for incorporating such a design. In 16 studies (55%), readers independently interpreted all images. However, the authors usually reported only the average interpretation of the readers; in only seven of the 29 studies (24%) did the authors describe differences among readers' interpretations. In 13 studies, interpretations were performed exclusively through "consensus reading." The method(s) used to achieve a consensus often were not explained. Only two of the 29 studies had more than three readers. In contrast, all of these studies included multiple patients. The average patient sample size was 45. Furthermore, differences observed among patients were routinely reported and/or depicted.

The safety and effectiveness of brain arteriovenous malformation embolization using acrylic and particles: the experiences of a single institution.

The purpose of this article is to report on the safety and effectiveness of brain arteriovenous malformation (AVM) embolization for two series of patients, of which one was treated with particulate embolization and the other with acrylic embolization. Sixty-five consecutive patients from embolization logs and patient records from 1988 to 1993 were reviewed. AVMs were routinely treated with particulate embolization early in the review (1988-1991), and after a transition period, the technique was changed to acrylic embolization for the remainder of the study period (1992-1993). All patients were treated with the ultimate goal of complete AVM obliteration. AVMs were embolized and resected, if possible, and if unresectable, they were reduced in size with embolization and radiated. The course of treatment for each patient was reviewed. The effectiveness at the end of treatment was analyzed for the ability to resect the AVM and, if unresectable, the ability to reduce the AVM to radiation size. Additionally, the safety of each embolization technique was evaluated in the context of comprehensive care, in terms of the safety of the procedure itself, the surgical resection after embolization, and the outcome at the end of comprehensive treatment. This article outlines the safety and effectiveness of acrylic and particulate embolization at a single institution. The ability to surgically resect an AVM after embolization and to reduce nidus size with acrylic was at least comparable with that with particulate embolization. Comprehensive complication rates were lower after acrylic embolization and were heavily influenced by a decreased number of surgical complications in the acrylic series. These data support the need to conduct a randomized prospective clinical trial to compare the relative safety and effectiveness of the two methods of embolization.

Ovarian carcinoma: value of CT in predicting success of debulking surgery.

OBJECTIVE: Initial therapy for metastatic epithelial ovarian adenocarcinoma involves aggressive surgery to remove as much tumor as possible. However, this procedure is not beneficial for patients unless tumor implants can be reduced to less than 2 cm in diameter. This study was performed to determine whether CT can be used to predict the success of debulking surgery and thereby spare some patients from an unnecessary operation. MATERIALS AND METHODS: Preoperative CT scans of 28 women who underwent primary surgery for ovarian carcinoma were retrospectively reviewed (18 patients had extrapelvic [stage III or IV] disease at surgery). Five regions were analyzed for evidence and extent of metastatic disease (omentum, liver, small bowel mesentery, paraaortic nodes, and diaphragm), and a score of 0-2 (see below) was assigned to each. These scores were added together for a total score of 0-10, which was compared with the surgical results. Receiver operating characteristic curve analysis was used to assess the ability of the scoring system to predict which patients would benefit from tumor debulking. Patient age, serum CA-125 level, and amount of ascites were also examined. RESULTS: On a 10-point preoperative CT scoring system, a score of 3 or higher identified patients whose tumors were not successfully debulked with a sensitivity of 58% (7/12) and a specificity of 100% (16/16). The area under the receiver operating characteristic curve for this system was 0.94. The use of additional parameters, such as extent of ascites, serum CA-125 level, or age, did not improve accuracy. CONCLUSION: Our results show that CT can be used to predict the success of primary debulking surgery in women with metastatic ovarian carcinoma. A significant number of patients in whom the surgery will have no benefit can be identified.