ABSTRACT
BACKGROUND: Small bowel obstruction (SBO) is a late complication of Roux-en-Y gastric bypass (RYGB). In non-pregnant patients, computed tomography (CT) is the first choice of imaging. During pregnancy, magnetic resonance imaging (MRI) is preferred to limit exposure to ionizing radiation. However, literature regarding the diagnostic accuracy of MRI for SBO is scarce. OBJECTIVE: To describe the diagnostic accuracy of MRI for SBO during pregnancy. METHODS: Pregnant women with RYGB suspected for SBO who presented at our center between September 2015 and April 2020 and who received an MRI scan (index) and underwent surgery (reference) were included. Original reports were retrospectively evaluated. Available MRI scans were structurally reinterpreted by two experienced radiologists. Statistical analysis included sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Cohen's kappa. RESULTS: Twenty-seven original MRI reports were included. Twenty-four (89%) MRIs were of good quality. Sensitivity was 67% (confidence interval (CI) 0.43-0.85), specificity 67% (CI 0.13-0.98), PPV 93% (CI 0.66-0.99), and NPV 22% (CI 0.04-0.60). MRI was unable to detect SBO in 1 out of 3 patients. The presence of swirl sign, SBO sign, or clustered loop sign increases the likelihood of SBO. The interobserver agreement was overall wide, with the highest score for swirl sign (κ 0.762). DISCUSSION: MRI is a safe and feasible alternative for CT. The value is doubtful as diagnostic accuracy shows wide ranges with considerable variability in the interobserver agreement. We would cautiously advise to perform MRI in case of a mild clinical presentation, but in case of a severe clinic, the diagnostic laparoscopy should remain the gold standard.
Subject(s)
Gastric Bypass , Intestinal Obstruction , Obesity, Morbid , Female , Gastric Bypass/adverse effects , Gastric Bypass/methods , Humans , Intestinal Obstruction/diagnostic imaging , Intestinal Obstruction/etiology , Intestinal Obstruction/surgery , Magnetic Resonance Imaging , Obesity, Morbid/surgery , Pregnancy , Pregnant Women , Retrospective Studies , Sensitivity and SpecificityABSTRACT
Intermittent clamping of the porta hepatis (PHC) is commonly performed during liver surgery to reduce blood loss and has been reported to precondition livers resulting in improved outcome after liver surgery (humans) and transplantation (animals). This study investigated the early expression of cytoprotective stress proteins during ischemia-reperfusion induced by PHC. Liver samples were taken before and after each event in a two-cycle ischemia-reperfusion protocol using 15 minutes of PHC followed by 5 minutes of reperfusion. Liver tissue was analyzed by real-time polymerase chain reaction for heme oxygenase (HO)-1 and heat shock protein (HSP)-70 mRNA expression. Extracted protein was analyzed by Western blot for HO-1, and HSP-70 and nuclear extracts were analyzed by DNA mobility shift assay for hypoxia inducible factor (HIF)-1alpha and heat shock factor (HSF)-1. Within minutes of PHC, significant increases in HO-1 mRNA expression were detected, and these were maintained throughout the protocol (P < 0.01). Protein expression of HO-1 (P < 0.03) and HO-1 activity (P < 0.05) were similarly increased between the start and end of ischemia- reperfusion (40 minutes). Binding of active HIF-1alpha to its consensus sequence was increased within 15 minutes of the start of the ischemia-reperfusion cycle. Although evidence of the transcriptionally active form of HSF-1 was detected at the same time point, this was not reflected in measurable changes in HSP-70 mRNA or protein. In conclusion, expression of the cytoprotective protein HO-1 is significantly up-regulated in the liver within minutes of PHC. It is likely that HO-1 contributes to the early protective effects of ischemic preconditioning.
