Search

Adhesive small bowel obstruction (SBO) remains one of the leading causes of emergency room visits and is still associated with high morbidity and mortality rates. Because the management of adhesive SBO has shifted from immediate surgery to nonoperative treatment in the absence of ischemia, it is crucial to rapidly detect or predict strangulation, which requires emergent surgery. CT is now established as the best imaging technique for the initial assessment of patients suspected of having adhesive SBO. CT helps confirm the diagnosis of mechanical SBO, locate the site of obstruction, establish the cause, and detect complications. This article is a review of the role of imaging in answering specific questions to help predict the management needs of each individual patient. It includes (a) an update on the best CT signs for predicting ischemia and a need for bowel resection; (b) a discussion of the CT features that help differentiate open-loop from closed-loop obstruction and a single adhesive band from matted adhesions and how these differences can influence the management; and (c) a review of the main CT predictors of the success or failure of nonoperative management in adhesive SBO., (© RSNA, 2020.)

Background Combined digital mammography (DM) and digital breast tomosynthesis (DBT) (hereafter, DM plus DBT) has increased cancer detection rates when compared with those achieved with DM-only screening. However, there is limited literature on DBT as an adjunct to mammography in the staging of known breast cancers. Purpose To compare the diagnostic accuracy of DM alone with that of DM plus DBT in the identification of additional ipsilateral and contralateral lesions in women with newly diagnosed breast cancer. Materials and Methods This prospective study ( https://clinicaltrials.gov , NCT01881880) included 166 women with breast cancer (mean age, 59.5 years ± 11; age range, 40-87 years) and used the aforementioned techniques, with breast MRI and pathologic verification of all suspected lesions as the reference standards. Four radiologists independently reviewed the DM and DM plus DBT images using the American College of Radiology Breast Imaging Reporting and Data Systems criteria for diagnosis of index lesions and presence of additional disease. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) obtained for DM and DM plus DBT were compared by using the McNemar test. Results Twenty-four women (14%) exhibited multifocal lesions; 20 (12%), multicentric lesions; 39 (23%), additional ipsilateral lesions; and 18 (11%), bilateral lesions. The sensitivities were higher for DM plus DBT than for DM in the diagnosis of multicentric (51% [41 of 80] vs 37% [30 of 80], P = .002) and additional ipsilateral (52% [81 of 156] vs 44% [69 of 156], P = .007) lesions. The AUC was larger for DM plus DBT than for DM (0.74 vs 0.67, P = .02) in the diagnosis of bilateral breast cancer. No significant differences in specificity were noted. The added diagnostic value of DBT was limited to the group of women with nondense breasts: For diagnosis of ipsilateral lesions, AUC of DM plus DBT versus DM was 0.74 versus 0.70 ( P = .04). For diagnosis of contralateral lesions, AUC of DM plus DBT verus DM was 0.76 versus 0.68 ( P = .02). Conclusion The combination of digital mammography with digital breast tomosynthesis improves diagnostic accuracy for additional ipsilateral and contralateral breast cancer in women with nondense breasts. © RSNA, 2019 See also the editorial by Moy in this issue.

Purpose To determine radiologic and clinical markers predictive of missed injuries at early whole-body CT image interpretation. Materials and Methods For this retrospective study, 2354 consecutive whole-body CT examinations were performed in patients with multiple traumas from 26 hospitals interpreted at a teleradiology center study during on-call period from February 2011 to September 2016. All whole-body CT images were interpreted by the on-call radiologist and reviewed within 12-48 hours by another radiologist to detect missed injury as the standard of reference. The first and review reports of all examinations were retrospectively reviewed. Univariable and multivariable logistic regression with a stepwise selection method were performed to identify clinical and radiologic predictors of missed injury. Results This study included 639 women (27.1%) and 1715 men (72.8%). The median age of men, women, and the entire population was 34 years (age range, 1-96 years). On a per-scan basis, there were 304 (12.9%) missed injuries and 59 (2.5%) were clinically significant. On a per-injury basis, the missed injury rate was 530 of 5979 (8.8%). More than two injured body parts (odds ratio, 1.4 [95% confidence interval: 1.1, 1.8]; P = .01), patient age older than 30 years (odds ratio, 2.8 [95% confidence interval: 2.1, 3.8]; P < .001), and an initial clinical severity class of 1 (odds ratio, 1.9 [95% confidence interval: 1.3, 2.8]; P < .001) were independent predictive factors of missed injury. Conclusion Multiple traumas with more than two injured body parts, age older than 30 years, or an initial clinical severity class of 1 were associated with missed injury at whole-body CT. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Novelline in this issue.

Purpose To determine which computed tomography (CT) findings or combinations of findings can help to accurately identify strangulation in adhesive small bowel obstruction (SBO). Materials and Methods Contrast agent-enhanced CT findings in a cohort of 256 patients consecutively admitted for adhesive SBO, with a delay of less than 24 hours between CT and surgery for the operated patients, were reviewed independently by two radiologists, with consensus by a third, to assess CT findings commonly associated with strangulation. The reference standard for strangulation was surgery. Univariate and multivariate analyses were performed to identify predictors of strangulation in the entire cohort and to identify predictors of the need for surgical resection in the subgroup of patients with strangulation. A CT score was obtained and diagnostic performances of different combined CT findings were calculated. Results In this study, 105 patients (41.0%; 105 of 256) underwent a surgical procedure, 62 of whom were found to have strangulation (59.0%; 62 of 105), whereas 151 patients (59.0%; 151 of 256) improved with medical care. Three CT findings were significantly associated with strangulation in the multivariate analysis: reduced bowel wall enhancement (odds ratio, 7.8; 95% confidence interval [CI]: 2.6, 23.5), diffuse mesenteric haziness (odds ratio, 6.1; 95% CI: 2.5, 15.2), and a closed-loop mechanism (odds ratio, 6.5; 95% CI: 2.8, 15.5). The model combining these three features had an area under the curve of 0.91 (95% CI: 0.86, 0.96) and a high negative predictive value (97%; 95% CI: 93%, 99%). Positive likelihood ratios were high when two or three of these CT findings were combined (positive likelihood ratios, 14.7 [95% CI: 7.1, 30.4] and 43.8 (95% CI: 14.2, 135.2], respectively). Among the strangulated cases, reduced bowel wall enhancement (odds ratio, 3.9; 95% CI: 1.3, 12) and mesenteric fluid (odds ratio, 3.6; 95% CI: 1.0, 12.8) were predictive of resection. Conclusion A score that combines three CT findings (reduced bowel wall enhancement, a closed-loop mechanism, and diffuse mesenteric haziness) can accurately predict strangulation in adhesive SBO. © RSNA, 2017 Online supplemental material is available for this article.

Purpose To assess the rate of underestimation of atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS) at magnetic resonance (MR) imaging-guided vacuum-assisted breast biopsy and to explore the imaging, demographic, and histologic characteristics associated with lesion upgrade after surgery. Materials and Methods This retrospective study had institutional review board approval, and the need to obtain informed patient consent was waived. A total of 1509 MR imaging-guided vacuum-assisted biopsy procedures were performed in nine centers. A diagnosis of ADH was obtained after biopsy in 72 cases, and a diagnosis of DCIS was obtained in 118 cases. Pearson χ 2 and Fisher tests were used to assess the association between demographic, MR imaging, and biopsy features and lesion upgrade. Univariate statistical analyses were performed, and each significant parameter was entered into a multivariate logistic regression analysis. Results Surgical excision was performed in 66 of the 72 ADH cases and in 117 of 118 DCIS cases. The ADH and DCIS underestimation rates were 25.8% (17 of 66) and 23.1% (27 of 117), respectively. Underestimation was 5.6-fold (odds ratio [OR] = 5.6; 95% confidence interval [CI]: 1.7, 18.3) and 3.6-fold (OR = 3.6; 95% CI: 1.2, 10) more likely in mass (n = 20 for ADH and n = 20 for DCIS) than in non-mass (n = 46 for ADH and n = 97 for DCIS), compared with nonunderestimation, in ADH and DCIS respectively. At multivariate analysis, the use of a 9- or 10-gauge needle versus a 7- or 8-gauge needle was also an independently associated with underestimation when a diagnosis of ADH was made at MR imaging-guided biopsy. No other parameters were associated with of ADH or DCIS upgrade at surgery. Conclusion The rates of underestimation in ADH and DCIS diagnosed at MR imaging-guided vacuum-assisted biopsy were high, at around 25%, and were significantly associated with the presence of a mass at MR imaging. © RSNA, 2016.

Purpose To determine whether adding unenhanced computed tomography (CT) to contrast material-enhanced CT improves the diagnostic performance of decreased bowel wall enhancement as a sign of ischemia complicating mechanical small bowel obstruction (SBO). Materials and Methods This retrospective study was approved by the institutional review board, which waived the requirement for informed consent. Two gastrointestinal radiologists independently performed retrospective assessments of 164 unenhanced and contrast-enhanced CT studies from 158 consecutive patients (mean age, 71.2 years) with mechanical SBO. The reference standard was the intraoperative and/or histologic diagnosis (in 80 cases) or results from clinical follow-up in patients who did not undergo surgery (84 cases). Decreased bowel wall enhancement was evaluated with contrast-enhanced images then and both unenhanced and contrast-enhanced images 1 month later. Diagnostic performance of decreased bowel wall enhancement and confidence in the diagnosis were compared between the two readings by using McNemar and Wilcoxon signed rank tests. Interobserver agreement was assessed by using κ statistics and compared with bootstrapping. Results Ischemia was diagnosed in 41 of 164 (25%) episodes of SBO. For both observers, adding unenhanced images improved decreased bowel wall enhancement sensitivity (observer 1: 46.3% [19 of 41] vs 65.8% [27 of 41], P = .02; observer 2: 56.1% [23 of 41] vs 63.4% [26 of 41], P = .45), Youden index (from 0.41 to 0.58 for observer 1 and from 0.42 to 0.61 for observer 2), and confidence score (P < .001 for both). Specificity significantly increased for observer 2 (84.5% [104 of 123] vs 94.3% [116 of 123], P = .002), and interobserver agreement significantly increased, from moderate (κ = 0.48) to excellent (κ = 0.89; P < .0001). Conclusion Adding unenhanced CT to contrast-enhanced CT improved the sensitivity, diagnostic confidence, and interobserver agreement of the diagnosis of ischemia, a complication of mechanical SBO, on the basis of decreased bowel wall enhancement. (©) RSNA, 2016.

Purpose: To identify computed tomographic (CT) findings that are associated with the effectiveness of nonsurgical treatment in patients with adhesive small-bowel obstruction ( SBO small-bowel obstruction ) that was initially treated medically., Materials and Methods: The local institutional review board approved this retrospective study; the informed consent requirement was waived. Multi-detector row CT studies in 159 patients (64 women, 95 men; median age, 69 years) with adhesive SBO small-bowel obstruction that was initially treated medically were reviewed retrospectively and independently by two emergency radiologists to identify numerous CT findings that could be associated with the effectiveness of nonsurgical treatment. Results were compared according to the success or failure of nonsurgical treatment. Univariate statistical analyses were performed for qualitative and quantitative data, as appropriate, and each significant parameter was entered in a multivariate logistic regression analysis. The κ statistic and correlation coefficients were used to assess interobserver agreement, as appropriate., Results: Nonsurgical treatment succeeded in 113 patients (71%) and failed in 46 patients (29%). At univariate analysis, an anterior parietal adhesion, a feces sign, and the lack of a beak sign were associated with successful nonsurgical treatment, whereas two beak signs or more, a whirl sign, a C- or U-shaped appearance of the bowel loop, and a high degree of obstruction were associated with nonsurgical treatment failure. At multivariate analysis, fewer than two beak signs and the presence of an anterior parietal adhesion were independent predictors of the effectiveness of nonsurgical treatment, with odds ratios of 0.27 and 0.11, respectively., Conclusion: The number of beak signs and the location of the transition zone in relation to the anterior peritoneal layer are independent signs associated with the success or failure of nonsurgical treatment.

Purpose: To retrospectively compare the kinetic magnetic resonance (MR) imaging characteristics of invasive breast carcinomas with both prognostic tumoral and patient-related parameters., Materials and Methods: This HIPAA-compliant retrospective study was approved by the institutional review board, and informed consent was waived. From January 2008 to January 2011, 273 consecutive women (mean age, 55 years; range, 23-83 years) with invasive breast cancers who had undergone MR imaging were selected. The kinetic curves were retrospectively classified according to the Breast Imaging Reporting and Data System lexicon. Initial enhancement and maximal enhancement percentages, time to peak enhancement, and the signal enhancement ratio were calculated for each lesion. Kinetic characteristics were compared according to tumoral parameters (size, pathologic type, grade, hormone receptor status, and c-erbB-2 status) and patient parameters (menopausal status, personal history of breast carcinoma) by means of univariate and then multivariate analysis by using false-discovery-rate statistics., Results: Lesions in menopausal patients exhibited less suspicious quantitative and qualitative characteristics than lesions in nonmenopausal patients. There was an independent association between the kinetic characteristics and menopausal status, with an odds ratio of 2.94 for the lack of rapid initial contrast material uptake and of 2.38 for the lack of washout in menopausal patients as compared with nonmenopausal patients. The odds ratio was 4.00 for not having rapid initial contrast material uptake in patients with a personal history of ipsilateral breast cancer., Conclusion: Kinetic data in invasive breast cancer are associated with the patient's menopausal status, with a typical kinetic pattern of malignancy being less common in menopausal patients., (© RSNA, 2013.)

Purpose: To retrospectively review the causes of false-negative results on prior magnetic resonance (MR) imaging studies in patients who developed breast cancer as revealed on a follow-up MR imaging study and to determine the presumptive causes of these false-negative findings., Materials and Methods: Fifty-eight pairs of MR imaging studies from one institution were assessed, consisting of a prior study without a diagnosis of cancer and a diagnostic study with subsequent findings of 60 cancers in 58 women at MR imaging (mean interval between prior and diagnostic MR examinations, 13.8 months). Two radiologists reviewed in consensus, in a nonblinded fashion, each pair of MR studies, comparing the diagnostic and the prior MR imaging studies to evaluate the rate of false-negative findings. The prospective reports were then analyzed to classify false-negatives findings in breast enhancement of breast cancers not identified at the time of imaging, potentially misinterpreted, and mismanaged. False-negative results on prior MR studies were retrospectively reassessed to identify possibly reasons why cancers had been not recognized, potentially misinterpreted, or mismanaged., Results: Twenty-eight (47% [95% confidence interval {CI}: 34%, 59%]) of the 60 cancers were retrospectively diagnosed as Breast Imaging Reporting and Data System grade 3, 4, or 5 lesions. Analysis of the prospective reports showed that six lesions (10% [95% CI: 2%, 18%]) had been not identified at the time of diagnosis, 15 lesions (25% [95% CI: 14%, 36%]) were potentially misinterpreted, and seven lesions (12% [95% CI: 3%, 20%]) were mismanaged. The main causes of misinterpretation were smooth margins of a mass (n=4), stability in size (n=3), and location of a nonmass in a postsurgical area (n=5). Mismanagement was mainly due to inadequate correlations between MR imaging and ultrasonographic (US) features, with inaccurate sampling with US guidance in five cases., Conclusion: In patients with breast cancer seen at MR imaging, retrospective evaluation of the prior MR imaging studies showed potential observer error in 47% of cases, resulting more from misinterpretation than from nonrecognition or mismanagement of cancers., (© RSNA, 2012.)