Magnetic resonance (MR) for mural nodule detection studying Intraductal papillary mucinous neoplasms (IPMN) of pancreas: Imaging-pathologic correlation.

PURPOSE: Magnetic Resonance (MR) is recommended to diagnose Intraductal Papillary Mucinous Neoplasms (IPMN) and in the follow-up of borderline lesions. The purpose of this work is to evaluate the diagnostic accuracy of dynamic MR with Diffusion Weighted Imaging (DWI) in the identification of mural nodules of pancreatic IPMN by using pathological analysis as gold standard. MATERIALS AND METHODS: Ninety-one preoperative MR with histopathological diagnosis of IPMN were reviewed by two radiologists. Presence, number and size of mural nodule, signal intensity of the nodule on T1-weighted imaging (T1-WI) after contrast medium administration and on DWI. Inter-observer agreement was evaluated. RESULTS: Significant correlation (p < 0.0001) were found for presence of nodules > 5 mm on MR and pathological specimen, size and number of mural nodules evaluated on pathological review and degree of dysplasia, size and number of mural nodules evaluated on MR and tumoral dysplasia, presence of nodule > 5 mm with enhancement after contrast medium administration and hyperintensity on DWI and degree of dysplasia. Interobserver agreement was moderate for the presence of mural nodule (K = 0.56), for the presence of high signal intensity on DWI (K = 0.57) and enhancement of mural nodule (K = 0.58). Apparent Diffusion Coefficient (ADC) map histogram analysis showed a correlation between Entropy of the entire cystic lesion and the degree of dysplasia (p < 0.034). CONCLUSIONS: MR with dynamic and DWI sequences was an accurate method for the identification of ≥ 5 mm solid nodules of the IPMNs and correlate with the lesion malignancy. Entropy, calculated from the histogram analysis of the IPMN ADC map, correlated with the lesion dysplasia.

Resectability of Pancreatic Cancer Is in the Eye of the Observer: A Multicenter, Blinded, Prospective Assessment of Interobserver Agreement on NCCN Resectability Status Criteria.

Objectives: To determine the reproducibility of the National Comprehensive Cancer Network (NCCN) resectability status classification for pancreatic cancer. Background: The NCCN classification defines 3 resectability classes (resectable, borderline resectable, locally advanced), according to vascular invasion. It is used to recommend different approaches and stratify patients during clinical trials. Methods: Prospective, multicenter, observational study (trial ID: NCT03673423). Main outcome measure was the interobserver agreement of tumor assignment to different resectability classes and quantification of vascular invasion degrees. Agreement was measured by Fleiss' k (k = 1 perfect agreement; k = 0 agreement by chance). Sixty-nine computed tomography (CT) scans of pathologically confirmed pancreatic adenocarcinoma were independently reviewed in a blinded fashion by 22 observers from 11 hospitals (11 surgeons and 11 radiologists). Rating differences between surgeons or radiologists and between hospitals with different volumes (≥60 or <60 resections/year) were assessed. Results: Complete agreement among 22 observers was recorded in 5 CT scans (7.2%), whereas 25 CT scans (36.2%) were variously assigned to all 3 resectability classes. Interobserver agreement varied from fair to moderate (Fleiss' k range: 0.282-0.555), with the lowest agreement for borderline resectable tumors. Assessing vascular contact ≤180° had the lowest agreement for all vessels (k range: 0.196-0.362). The highest concordance was recorded for venous invasion >180° (k range: 0.619-0.756). Neither reviewers' specialty nor hospital volume influenced the agreement. Conclusions: There is high variability in the assignment to resectability categories, which may compromise the reliability of treatments recommendations and the evidence of trials stratifying patients in resectability classes. Criteria should be revised to allow a reproducible classification.

Clinical use of contrast-enhanced ultrasound beyond the liver: a focus on renal, splenic, and pancreatic applications.

Contrast-enhanced ultrasound (CEUS) is a relatively novel, but increasingly used, diagnostic imaging modality. In recent years, due to its safety, quickness, and repeatability, several studies have demonstrated the accuracy, specificity, and sensitivity of CEUS. The European Federation of Societies for Ultrasound in Medicine and Biology has recently updated the previous guidelines from 2012 for the use of CEUS in non-hepatic applications. This review deals with the clinical use and applications of CEUS for the evaluation of non-hepatic abdominal organs, focusing on renal, splenic, and pancreatic applications.

Effect of Age on High T1 Signal Intensity of the Dentate Nucleus and Globus Pallidus in a Large Population Exposed to Gadodiamide.

OBJECTIVE: The purpose of this study was to assess the effect of age and number of previous injections of gadodiamide on the signal intensity of unenhanced T1-weighted (T1w) images of the dentate nucleus and globus pallidus in a large population. MATERIALS AND METHODS: A large, single-center retrospective population survey was designed and received institutional review board approval. Between January 2014 and December 2014, T1w signal intensity ratios were obtained from a large population of 2500 consecutive enhanced brain magnetic resonance imaging (MRI) scans. Of these, 1906 MRI scans of patients not previously exposed to any gadolinium (Gd)-based contrast agent were used as control group and were compared with 892 MRI scans of patients with documented prior exposure to intravenous gadodiamide. A quantitative study was conducted to assess the T1w signal intensity of dentate nucleus-to-pons (Dn/Po) and globus pallidus-to-thalamus (Gp/Th) ratios. Multiple regression analysis was used to test the effect of age, time delay, and number of previous Gd-based contrast agent injections as predictor variables of T1w signal intensity ratios. RESULTS: In the Gd-exposed patients, multivariate regression analysis showed age (ß = -0.285; P < 0.0001) and the number of previous injections of gadodiamide (ß = 0.224; P < 0.0001) to be powerful predictors of Dn/Po ratio. Similarly, age (ß = 0.269; P < 0.0001) and the number of previous injections of gadodiamide (ß = 0.127; P < 0.0001) predicted Gp/Th ratio. CONCLUSIONS: In this study, we confirm that the number of previous gadodiamide injections is a powerful predictor of the signal intensity increase of the Dn/Po and Gp/Th ratios on unenhanced T1w images and demonstrate that aging influences the T1 signal intensity of DN and GP in Gd-naïve and in Gd-exposed subjects.