A. Dohan

Pitfalls and mimickers at 64-section helical CT that cause negative appendectomy: an analysis from 1057 appendectomies

PURPOSE To determine the rate of negative appendectomy and clarify the causes of negative appendectomy in patients with clinically suspected acute appendicitis who had surgery after 64-section helical computed tomography (CT). MATERIAL AND METHODS A retrospective analysis of 1057 patients who had appendectomy after 64-section helical CT was performed to determine the rate of negative appendectomy. The 64-section helical CT examinations obtained with submillimeter and isotropic voxels in the patients with negative appendectomy were analyzed by two readers and compared to clinical, operative and histopathological reports, discharge summaries and original radiology reports. RESULTS The negative appendectomy rate was 1.7% (18/1057). Appendix enlargement (>6 mm) and fat stranding were present in 17 (17/18; 94%) and 6 patients (6/18; 33%), respectively. In 13 patients (13/18; 72%) 64-section helical CT findings were consistent with acute appendicitis. Interpretive errors in original imaging reports were identified in five patients (5/18; 28%). CONCLUSION The preoperative use of 64-section helical CT results in a very low rate of negative appendectomy. Patients with negative appendectomy have 64-section helical CT findings consistent with a diagnosis of acute appendicitis in the majority of cases. Interpretive errors are less frequent.

Carcinoid tumors of the small-bowel: Evaluation with 64-section CT-enteroclysis

PURPOSE To describe the imaging presentation of carcinoid tumors of the small-bowel at 64-section CT-enteroclysis and determine the sensitivity of this technique for tumor detection. PATIENTS AND METHODS The 64-section CT-enteroclysis examinations of 22 patients with histopathologically proven small-bowel carcinoid tumors and those of 6 patients with suspected recurrence after small-bowel resection for carcinoid tumor were reviewed. Images were analyzed with respect to imaging presentation. Sensitivity, specificity, and accuracy, of 64-section CT-enteroclysis for the diagnosis of carcinoid tumor of the small-bowel were estimated with 95% confidence intervals (CIs). RESULTS Twenty-five carcinoid tumors were confirmed in 22 patients (prevalence, 22/28; 79%). Overall sensitivity for carcinoid tumor detection was 76% (19/25; 95%CI: 55-91%) on a per-lesion basis. On a per-patient basis, 64-section CT-enteroclysis had a sensitivity of 86% (19/22; 95%CI: 65-97%), a specificity of 100% (6/6; 95%CI: 54-100%) and an accuracy of 89% (25/28; 95%CI: 72-98%) for the diagnosis of carcinoid tumor. Focal small-bowel wall thickening, mesenteric stranding, and mesenteric mass were found in 20/22 (91%), 18/22 (82%) and 15/22 (68%) patients with pathologically confirmed tumors. CONCLUSION 64-Section CT-enteroclysis shows highly suggestive features for the diagnosis of carcinoid tumor of the small-bowel and achieves high degrees of sensitivity for tumor detection.

Transjugular liver biopsy: Indications, technique and results

Transjugular liver biopsy is a safe, effective and well-tolerated technique to obtain liver tissue specimens in patients with diffuse liver disease associated with severe coagulopathies or massive ascites. Transjugular liver biopsy is almost always feasible. The use of ultrasonographic guidance for percutaneous puncture of the right internal jugular vein is recommended to decrease the incidence of local cervical minor complications. Semiautomated biopsy devices are very effective in obtaining optimal tissue samples for a precise and definite histological diagnosis with a very low rate of complication. The relative limitations of transjugular liver biopsy are the cost, the radiation dose given to the patient, the increased procedure time by comparison with the more common percutaneous liver biopsy, and the need of a well-trained interventional radiologist.

Endometrial Carcinoma: MR Imaging–based Texture Model for Preoperative Risk Stratification—A Preliminary Analysis

Purpose To evaluate the associations among mathematical modeling with the use of magnetic resonance (MR) imaging-based texture features and deep myometrial invasion (DMI), lymphovascular space invasion (LVSI), and histologic high-grade endometrial carcinoma. Materials and Methods Institutional review board approval was obtained for this retrospective study. This study included 137 women with endometrial carcinomas measuring greater than 1 cm in maximal diameter who underwent 1.5-T MR imaging before hysterectomy between January 2011 and December 2015. Texture analysis was performed with commercial research software with manual delineation of a region of interest around the tumor on MR images (T2-weighted, diffusion-weighted, and dynamic contrast material-enhanced images and apparent diffusion coefficient maps). Areas under the receiver operating characteristic curve and diagnostic performance of random forest models determined by using a subset of the most relevant texture features were estimated and compared with those of independent and blinded visual assessments by three subspecialty radiologists. Results A total of 180 texture features were extracted and ultimately limited to 11 features for DMI, 12 for LVSI, and 16 for high-grade tumor for random forest modeling. With random forest models, areas under the receiver operating characteristic curve, sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were estimated at 0.84, 79.3%, 82.3%, 81.0%, 76.7%, and 84.4% for DMI; 0.80, 80.9%, 72.5%, 76.6%, 74.3%, and 79.4% for LVSI; and 0.83, 81.0%, 76.8%, 78.1%, 60.7%, and 90.1% for high-grade tumor, respectively. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of visual assessment for DMI were 84.5%, 82.3%, 83.2%, 77.7%, and 87.8% (reader 3). Conclusion The mathematical models that incorporated MR imaging-based texture features were associated with the presence of DMI, LVSI, and high-grade tumor and achieved equivalent accuracy to that of subspecialty radiologists for assessment of DMI in endometrial cancers larger than 1 cm. However, these preliminary results must be interpreted with caution until they are validated with an independent data set, because the small sample size relative to the number of features extracted may have resulted in overfitting of the models.

Observational study on the safety profile of gadoterate meglumine in 35,499 patients: The SECURE study.

To investigate the safety of gadoterate meglumine and identify the incidence of nephrogenic systemic fibrosis (NSF).

Intrahepatic and hilar mass-forming cholangiocarcinoma: Qualitative and quantitative evaluation with diffusion-weighted MR imaging

OBJECTIVE To qualitatively and quantitatively analyze the presentation of intrahepatic and hilar mass-forming cholangiocarcinoma with diffusion-weighted magnetic resonance imaging (DW-MRI). MATERIALS AND METHODS Twenty-eight patients with histopathologically proven mass-forming cholangiocarcinoma (hilar, n=17; intrahepatic, n=11) underwent hepatic DW-MRI at 1.5-T using free-breathing acquisition and three b-values (0,400,800s/mm(2)). Cholangiocarcinomas were evaluated qualitatively using visual analysis of DW-MR images and quantitatively with conventional ADC and normalized ADC measurements using liver and spleen as reference organs. RESULTS All cholangiocarcinomas (28/28; 100%) were visible on DW-MR images. DW-MRI yielded best conspicuity of cholangiocarcinomas than the other MRI sequences (P<0.001). Seven cholangiocarcinomas (7/11; 64%) showed hypointense central area on DW-MR images. Conventional ADC value of cholangiocarcinomas (1.042×10(-3)mm(2)/s±0.221×10(-3)mm(2)/s; range: 0.616×10(-3)mm(2)/s to 2.050×10(-3)mm(2)/s) was significantly lower than that of apparently normal hepatic parenchyma (1.362×10(-3)mm(2)/s±0.187×10(-3)mm(2)/s) (P<0.0001), although substantial overlap was found. No significant differences in ADC and normalized ADC values were found between intrahepatic and hilar cholangiocarcinomas. The use of normalized ADC using the liver as reference organ resulted in the most restricted distribution of ADC values of cholangiocarcinomas (variation coefficient=16.6%). CONCLUSION There is a trend towards a common appearance of intrahepatic and hilar mass-forming cholangiocarcinomas on DW-MRI but variations may be observed. Familiarity with these variations may improve the diagnosis of mass-forming cholangiocarcinoma.

Intra-abdominal benign multicystic peritoneal mesothelioma

Benign multicystic peritoneal mesotheliomas are rare: pre-operative diagnosis relies on proper imaging. The differential diagnosis includes pseudomyxoma peritonei and other peritoneal cysts. Absence of previous surgical resection offers the best chance of success when complete resection is performed in a specialized center. We report the case of a 43 year-old man with benign multicystic peritoneal mesothelioma treated by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

Pitfalls and mimickers on (18)F-FDG-PET/CT in peritoneal carcinomatosis from colorectal cancer: An analysis from 37 patients.

BACKGROUND Optimal selection is critical in patients with peritoneal carcinomatosis (PC) in whom curative cytoreductive surgery can be anticipated. (18)F-FDG-PET/CT may result in false-positive findings that may eliminate patients for whom cytoreductive surgery would be beneficial. OBJECTIVES To determine the rate of false-positive findings on (18)F-FDG-PET/CT and clarify their causes in patients with suspected PC from colorectal cancer. METHODS A retrospective analysis of 37 patients with suspected PC from colorectal cancer who had (18)F-FDG-PET/CT before cytoreductive surgery was performed to determine the rate and the causes of false-positive findings. (18)F-FDG-PET/CT was considered falsely positive when no tumor was found at surgery, histopathological analysis and follow-up. RESULTS False-positive findings were observed in four patients, yielding a 11% (95%CI: 3-25%) false-positive rate on a per-patient basis. The causes of false-positives were elucidated in two patients (surgical mesh after umbilical hernia repair and one foreign body granuloma). CONCLUSION False-positive findings on (18)F-FDG-PET/CT are observed in 11% of patients with suspected PC from colorectal cancer. Familiarity with false-positive findings would result in more accurate selection of patients candidates to cytoreductive surgery.

Evaluation of the peritoneal carcinomatosis index with CT and MRI

The aim was to determine the incremental value of MRI compared with CT in the preoperative estimation of the peritoneal carcinomatosis index (PCI).

Diffusion-weighted magnetic resonance imaging in colorectal cancer

Magnetic resonance imaging (MRI) plays now a major role in patients with colorectal cancer regarding tumor staging, surgical planning, therapeutic decision, assessment of tumor response to chemoradiotherapy and surveillance of rectal cancer, and detection and characterization of liver or peritoneal metastasis of colorectal cancers. Diffusion-weighted MRI (DW-MRI) is a functional imaging tool that is now part of the standard MRI protocol for the investigation of patients with colorectal cancer. DW-MRI reflects micro-displacements of water molecules in tissues and conveys high degrees of accuracy to discriminate between benign and malignant colorectal conditions. Thus, in addition to morphological imaging, DW-MRI has an important role to accurately detect colorectal neoplasms and peritoneal implants, to differentiate benign focal liver lesions from metastases and to detect tumor relapse within fibrotic changes. This review provides a comprehensive overview of basic principles, clinical applications and future trends of DW-MRI in colorectal cancers.