Increased unenhanced bowel-wall attenuation at multidetector CT is highly specific of ischemia complicating small-bowel obstruction.

PURPOSE: To evaluate performance of increased bowel-wall attenuation on unenhanced 64-section multidetector computed tomographic (CT) images for diagnosing bowel-wall ischemia in patients with mechanical small-bowel obstruction (SBO) and to evaluate the diagnostic accuracy of multidetector CT in detecting small-bowel ischemia complicating SBO, with surgical and histopathologic findings as reference standard. MATERIALS AND METHODS: The local institutional review board approved this retrospective study; informed consent requirement was waived. In 44 patients (10 men, 34 women; age range, 30-100 years) who were admitted because they were suspected of having SBO and treated surgically within the next 7 days, 45 multidetector CT scans were retrospectively reviewed. Two gastrointestinal radiologists performed independent blinded reviews of images to identify specific signs of ischemia; disagreements were resolved in consensus with a third gastrointestinal radiologist. Results were compared with both findings in prospective radiology reports and surgical and histopathologic findings. Fisher exact and χ(2) tests were used to assess associations between CT signs and ischemia, and the κ statistic was used to assess interobserver agreement. RESULTS: In 19 of 45 (42%) multidetector CT scans, ischemia was confirmed at surgery and/or histopathologic examination. Increased bowel-wall attenuation on unenhanced images was significantly associated with ischemia (P < .0001); in this highly selected population, this sign had a 100% (24 of 24) specificity and a 56% (10 of 18) sensitivity. Sensitivity and specificity of multidetector CT for ischemia were 63% (12 of 19) and 92% (24 of 26), respectively, for the prospective reports and 84% (16 of 19) and 96% (25 of 26), respectively, for the consensus review. Decreased segmental bowel-wall enhancement was the most accurate 64-section multidetector CT sign for diagnosing ischemia (sensitivity, 78% [14 of 18]; specificity, 96% [24 of 25]; P < .0001). The small-bowel feces sign was significantly associated with ischemia (P = .0308). CONCLUSION: Increased bowel-wall attenuation on unenhanced 64-section multidetector CT images is a specific sign for ischemia complicating SBO. Diagnostic accuracy of 64-section multidetector CT for ischemia associated with SBO was excellent.

Assessment of the drug susceptibility of Plasmodium falciparum clinical isolates from africa by using a Plasmodium lactate dehydrogenase immunodetection assay and an inhibitory maximum effect model for precise measurement of the 50-percent inhibitory concentration.

The extension of drug resistance among malaria-causing Plasmodium falciparum parasites in Africa necessitates implementation of new combined therapeutic strategies. Drug susceptibility phenotyping requires precise measurements. Until recently, schizont maturation and isotopic in vitro assays were the only methods available, but their use was limited by technical constraints. This explains the revived interest in the development of replacement methods, such as the Plasmodium lactate dehydrogenase (pLDH) immunodetection assay. We evaluated a commercially controlled pLDH enzyme-linked immunosorbent assay (ELISA; the ELISA-Malaria antigen test; DiaMed AG, Cressier s/Morat, Switzerland) to assess drug susceptibility in a standard in vitro assay using fairly basic laboratory equipment to study the in vitro resistance of malaria parasites to major antimalarials. Five Plasmodium falciparum clones and 121 clinical African isolates collected during 2003 and 2004 were studied by the pLDH ELISA and the [8-(3)H]hypoxanthine isotopic assay as a reference with four antimalarials. Nonlinear regression with a maximum effect model was used to estimate the 50% inhibitory concentration (IC(50)) and its confidence intervals. The two methods were observed to have similar reproducibilities, but the pLDH ELISA demonstrated a higher sensitivity. The high correlation (r = 0.98) and the high phenotypic agreement (kappa = 0.88) between the two methods allowed comparison by determination of the IC(50)s. Recently collected Plasmodium falciparum African isolates were tested by pLDH ELISA and showed drug resistance or decreased susceptibilities of 62% to chloroquine and 11.5% to the active metabolite of amodiaquine. No decreased susceptibility to lumefantrine or the active metabolite of artemisinin was detected. The availability of this simple and highly sensitive pLDH immunodetection assay will provide an easier method for drug susceptibility testing of malaria parasites.