E. Pages

Pearls and pitfalls in breast MRI

At our academic institution, we have noticed repeated examples of both false-positive and false-negative MR diagnoses in breast cancer. The most common diagnostic errors in interpreting MRI of the breast are discussed in this review and experience-based advice is provided to avoid similar mistakes. The most common reasons for false-positive diagnoses are misinterpretation of artefacts, confusion between normal enhancing structures and tumours and, above all, insufficient use of the American College of Radiology breast imaging reporting and data system lexicon, whereas false-negative diagnoses are made as a result of missed tiny enhancement, a background-enhancing breast, or enhancement interpreted as benign rather than malignant.

Adhesive Small-Bowel Obstruction: Value of CT in Identifying Findings Associated with the Effectiveness of Nonsurgical Treatment

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.

Undiagnosed Breast Cancer at MR Imaging: Analysis of Causes

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.

Mechanical occlusions: Diagnostic traps and key points of the report

Management of mechanical occlusion, particularly of the small intestine, has altered considerably over recent years, with a change of paradigm and the indication for surgery depending on the cause of the occlusion and any signs of entrapment or strangulation. It is therefore important today to make a positive diagnosis of mechanical occlusion, to assess its degree, its location and its cause, and to look for signs of entrapment and strangulation. Only computer tomography can provide the answers to these different questions. The aim of this paper is to provide a reminder of the CT signs that enable us to confirm diagnosis of the various aspects of mechanical occlusion of the stomach and duodenum, small intestine or colon, to emphasize and illustrate the diagnostic traps in CT and to set out the key points of a CT report of mechanical occlusion.

Infection of the right iliac fossa.

Febrile pain in the right iliac fossa is one of the most common reasons for consulting at an emergency service. Within this framework, the main diagnosis that is considered is appendicitis, the main complication of which is perforation. However, a certain number of other conditions can be responsible for this clinical picture, primarily including digestive tract and mesentery disorders including mesenteric lymphadenitis, Crohns disease, infectious enterocolitis, small intestine or colonic diverticulitis, ischaemic colitis or cancer of the caecum. This article illustrates the imaging semiology of the various right colonic, iliac, mesenteric and appendicular conditions that could potentially cause an infection of the right iliac fossa. It specifies the indications of ultrasound and CT scans, respectively, which depend on the age of the patient and the clinical signs and symptoms. Though the CT scan is commonly used in abdominal emergencies in general, and particularly in clinical pictures of infection of the right iliac fossa, ultrasound remains recommended as first line imaging when confronted with suspected appendicitis or lymphadenitis in a young subject or in the monitoring of Crohns disease.

CT of gastro-duodenal obstruction

Gastro-duodenal obstruction encompasses a spectrum of benign and malignant disease. Historically, chronic peptic ulcer disease was the main cause of gastro-duodenal obstruction, whereas now malignant cause with gastric carcinomas for gastric obstruction and pancreatic tumors for duodenal obstruction predominate. This paper reviews the role of CT in diagnosing gastro-duodenal obstruction, its level, its cause by identifying intraluminal, parietal, or extrinsic process, and the presence of complication.

Correlation between MR imaging – prognosis factors and molecular classification of breast cancers

The molecular classification of breast cancers defines subgroups of cancer with different prognoses and treatments. Each molecular type representing the intrinsic signature of the cancer corresponds to a histological profile incorporating hormone receptors, HER2 status and the proliferation index. This article describes the correlations between this molecular classification obtained in routine clinical practice using histological parameters and MRI. It shows that there is a specific MRI profile for triple-negative cancers: distinct demarcation, regular edges, hyperintensity on T2 weighted signals and, particularly, a crown enhancement. It is important for the radiologist to understand this molecular classification, firstly because of the relatively suggestive appearance of triple-negative basal-like cancers in the molecular classification, secondly, and particularly, as cancers in patients with the BRCA1 mutation are often triple-negative meaning that the criteria for reading the MRI needs to be tailored to this feature of the cancers, and finally because the efficacy of MRI in assessing response to neoadjuvant chemotherapy depends on the molecular class of cancer treated.