Ingrid Millet

Characterization of Small Solid Renal Lesions: Can Benign and Malignant Tumors Be Differentiated With CT?

OBJECTIVE The purpose of this study was to evaluate the diagnostic performance of CT in determining whether a small solid renal enhancing mass is benign or malignant. MATERIALS AND METHODS Ninety-nine biopsies of enhancing solid renal masses 4 cm or smaller without fat on CT scans were performed under CT fluoroscopic guidance. The growth pattern, interface with parenchyma, presence of a scar and segmental inversion enhancement, unenhanced CT histogram, and pattern and degree of enhancement on triphasic MDCT images were independently evaluated by two radiologists. Biopsy and pathology reports were used as the reference standard, and imaging follow-up of benign lesions was performed for at least 1 year. Statistical analysis was performed to determine the significance of CT criteria in differentiating malignant from benign lesions. RESULTS Of the 99 lesions, 74 (75%) were malignant at biopsy, and 25 (25%) were benign. Lesions with gradual enhancement were more likely to be benign. No significant correlation was found between other CT features and a malignant or benign diagnosis. The sensitivity, specificity, and positive and negative predictive values of progressive enhancement for a diagnosis of benignity were 60%, 73%, 43%, and 84%. CONCLUSION In the evaluation of enhancing small solid renal lesions without fat, no CT criteria were of substantial help in differentiating malignant from benign lesions.

Direct visualization of perforation sites in patients with a non-traumatic free pneumoperitoneum: added diagnostic value of thin transverse slices and coronal and sagittal reformations for multi-detector CT

The incremental diagnostic value of adding 1.25-mm slices and coronal and sagittal reformatting to 5-mm axial reconstructions for direct visualization of the perforation site in patients with non-traumatic free pneumoperitoneum was assessed. Forty patients with non-traumatic bowel perforation and free pneumoperitoneum underwent computed tomography (CT). The perforation was gastroduodenal in 18 patients and involved the small or large bowel in 22 patients. Transverse scans were reconstructed with 5-mm thick sections at 5-mm intervals and 1.25-mm-thick sections at 1.25-mm intervals. The second data set was reformatted coronally and sagittaly with 3-mm-thick sections at 3-mm intervals. Three independent blinded readers interpreted 5-mm transverse scans, then combined 1.25-mm and 5-mm-transverse scans, and then combined transverse, coronal and sagittal scans. The rate of identification of the perforation site ranged from 43% to 53% with the combined axial, sagittal and coronal scans, from 28% to 48% with the 1.25- and 5-mm transverse scans, and from 5% to 20% only with the 5-mm thick transverse scans. The agreement between readers was significantly higher with thin slices and reformatting. The use of 1.25-mm axial slices and reformations intrinsically contained more useful diagnostic information than 5-mm axial slices alone for diagnosis of the perforation site in patients with pneumoperitoneum.

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.

What are the specific computed tomography scan criteria that can predict or exclude the need for renal angioembolization after high-grade renal trauma in a conservative management strategy?

BACKGROUND The indications of renal angioembolization for patients with high-grade renal trauma (HGRT) are based on angiographic criteria to reduce the failure rate of conservative management (CM). There is no consensus to predict or exclude an indication of renal angioembolization with a computed tomography (CT) scan. The aim of this study was to evaluate CT-specific criteria to predict or exclude the need for renal embolization. METHODS All traumatized patients admitted with renal injury were considered between 2005 and 2009. We included all patients who had an HGRT (classified by American Association for the Surgery of Trauma Organ Injury Scale grade≥3) treated by CM. We collected the demographic, CT, angiographic, management, and outcome data for these patients. CT criteria were retrospectively studied to define their predictive values for renal embolization. RESULTS Among 101 patients with renal injury, 58 were HGRT, and 53 of them were treated by CM. Ten patients (19%) received renal embolization because of an ongoing renal hemorrhage. There was no significant difference for urologic interventions (2 [20%] vs. 7 [16%]), CM failure rate (1 [10%] vs. 2 [5%]), and during hospital stay between these patients and those who did not received embolization. None of the CT criteria had a negative predictive value for renal embolization to 100%, only the absence of intravascular contrast extravasation associated with a perirenal hematoma rim distance<25 mm excludes an indication for embolization. CONCLUSIONS In patients with HGRT who had bleeding, a strategy of targeted angiography can be realized safely in using specific CT scan criteria that can predict with high accuracy and exclude the need for embolization, without reducing the success rate of CM.

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.

Effect of renal angioembolization on post-traumatic acute kidney injury after high-grade renal trauma: a comparative study of 52 consecutive cases.

BACKGROUND Acute kidney injury (AKI) is associated with unfavourable outcomes and higher mortality after trauma. Renal angioembolization (RAE) has proved efficiency in the management of high-grade renal trauma (HGRT), but inevitably expose to unavoidable ischaemic areas or contrast medium nephrotoxicity which may impair renal function in the following hours. The aim of this study was to assess the potential acute impact of RAE on renal function in a consecutive series of HGRTs treated nonoperatively. MATERIALS AND METHODS Of 101 cases of renal trauma admitted to our Regional Trauma Center between January 2005 and January 2010, 52 cases of HGRT were treated nonoperatively; they were retrospectively classified into 2 groups according to whether RAE was used. Incidence and progression of AKI (RIFLE classification), maximum increase in serum creatinine (SCr), level since admission and recovery of renal function at discharge were compared between the groups. Multivariable analysis was performed to determine the role of RAE as an independent risk factor of AKI. RESULTS RAE was performed in 10 patients within the first 48h. The RAE and no RAE groups were comparable in terms of severity score, renal injury grade, and level of SCr on admission. AKI incidence (RIFLE score Risk or worse) after 48 and 96h was 33% and 10%, respectively and did not differ significantly between groups at 48h (p=1.00) or 96h (p=1.00). The median maximum increase in SCr was significantly higher in no RAE than RAE group (30.4% vs. 6.9%, p=0.04). RAE was not found to be a significant variable in a multiple linear regression analysis predicting maximum SCr rise (p=0.34). SCr at discharge was >120% of baseline in only 5 patients, with no difference according to RAE (p=0.24). CONCLUSION In a population of nonoperatively treated HGRT, the incidence of AKI decreased from almost 30% to 10% at 48h and 96h. RAE proceeding did not seem to affect significantly the occurrence and course of AKI or renal recovery. The decision to use RAE should probably not be restricted by fear of worsening renal function.

Thoracic Trauma Severity score on admission allows to determine the risk of delayed ARDS in trauma patients with pulmonary contusion.

BACKGROUND Pulmonary contusion is a major risk factor of acute respiratory distress syndrome (ARDS) in trauma patients. As this complication may appear after a free interval of 24-48 h, detection of patients at risk is essential. The main objective of this study was to assess the performance of the Thoracic Trauma Severity (TTS) score upon admission in predicting delayed ARDS in blunt trauma patients with pulmonary contusion. METHODS All blunt thoracic trauma patients admitted consecutively to our trauma centre between January 2005 and December 2009 were retrospectively included if they presented a pulmonary contusion on the admission chest computed tomography scan. Main outcome measure was the presence of moderate or severe ARDS (PaO2/FiO2 ratio≤200) for 48 h or more. The global ability of the TTS score to predict ARDS was studied by ROC curves with a threshold analysis using a grey zone approach. RESULTS Of 329 patients studied (75% men, mean age 36.9 years [SD 17.8 years], mean Injury Severity Score 21.7 [SD 16.0]), 82 (25%) presented with ARDS (mean lowest PaO2/FiO2 ratio of 131 [SD 34]). The area under the ROC curves for the TTS score in predicting ARDS was 0.82 (95% CI 0.78-0.86) in the overall population. TTS scores between 8 and 12 belonged to the inconclusive grey zone. A TTS score of 13-25 was found to be independent risk factors of ARDS (OR 25.8 [95% CI 6.7-99.6] P<0.001). CONCLUSIONS An extreme TTS score on admission accurately predicts the occurrence of delayed ARDS in blunt thoracic trauma patients affected by pulmonary contusion. This simple score could guide early decision making and management for a non-negligible proportion of this specific population.

Assessing the classification of liver focal lesions by using multi-phase computer tomography scans

In this paper, we propose a system for the automated classification of liver focal lesions of Computer Tomography (CT) images based on a multi-phase examination protocol. Many visual features are first extracted from the CT-scans and then labelled by a Support Vector Machine classifier. Our dataset contains 95 lesions from 5 types: cysts, adenomas, haemangiomas, hepatocellular carcinomas and metastasis. A Leave-One-Out cross-validation technique allows for classification evaluation. The multi-phase results are compared to the single-phase ones and show a significant improvement, in particular on hypervascular lesions.

Assessment of Bowel Wall Enhancement for the Diagnosis of Intestinal Ischemia in Patients with Small Bowel Obstruction: Value of Adding Unenhanced CT to Contrast-enhanced CT

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.