Interobserver agreement for detection of malignant features of intraductal papillary mucinous neoplasms of the pancreas on MDCT

Abdominal ultrasound in the characterization of branch-duct intraductal papillary mucinous neoplasms: A new tool for surveillance of low-risk patients?

BACKGROUND

Magnetic resonance imaging (MRI) is regarded as gold-standard for intraductal papillary mucinous neoplasms (IPMNs) follow-up. Given the low risk of transformation and the increasing population under surveillance, there is growing interest in identifying optimal follow-up strategies.

AIM

To evaluate reliability of abdominal ultrasound (US) for characterization of low-risk IPMN, compared to MRI.

METHODS

Prospective monocentric study among 79 consecutive patients with a suspected BD-IPMN on US. Each patient underwent confirmatory MRI. We evaluated Cohen's kappa statistic and concordance rate (CR) between MRI and US.

RESULTS

Of 79 suspected IPMNs on US, MRI confirmed 71 BD-IPMNs. There was high agreement for cyst location and number (CR and kappa of 77.5 % and 81.7 % and 0.66±0.08 and 0.62±0.11 respectively). We found high agreement for cyst size (CR=96.5 %, kappa=0.93±0.05) and main pancreatic duct (MPD) dilatation (CR=100 %, kappa=1). There was a good agreement for thickened septa (CR=80.3 %, kappa=0.38±0.12). US seems inferior to MRI for the identification of mural nodules < 5 mm (CR=97.2 %, kappa=0).

CONCLUSIONS

In a cohort of low-risk BD-IPMN, US presented high agreement rate with MRI regarding location, number, and size. There was a good agreement for MPD dilatation and thickened septa, while US underperform for detection of mural nodules < 5 mm.

Association of high-risk stigmata and worrisome features with advanced neoplasia in intraductal papillary mucinous neoplasms (IPMN): A systematic review

BACKGROUND

This systematic review aimed to assess the diagnostic accuracy of the International Consensus Fukuoka Guidelines (ICG2017) in identifying high-risk lesions of Intraductal Papillary Mucinous Neoplasms (IPMNs).

METHODS

The ICG2017 revision committee conducted a comprehensive literature review to establish evidence-based statements on IPMNs. The review focused on articles examining the diagnostic value of imaging features (e.g., cyst or main pancreatic duct diameter), clinical symptoms associated with IPMN, and serum biomarkers. Five clinical questions regarding high-risk stigmata (HRS) and worrisome features (WF) in the ICG2017 guidelines were addressed.

RESULTS

A total of 210 articles were reviewed. The findings revealed a significant association between the presence of mural nodules ≥5 mm in diameter or solid components with contrast enhancement and the diagnosis of high-grade dysplasia or invasive carcinoma. Contrast-enhanced diagnostic tools, such as CT, MRI, or EUS, demonstrated the highest prediction rate and were recommended. Positive cytology was identified as an HRS, while symptoms like acute pancreatitis and cyst diameter growth ≥2.5 mm per year were considered WFs. The use of nomograms and multiple diagnostic factors was recommended for optimal IPMN management.

CONCLUSIONS

This systematic review provides evidence supporting the improved diagnostic accuracy of ICG2017 in identifying high-risk lesions of IPMN. The multidisciplinary incorporation of HRS and WF based on imaging findings and clinical symptoms is crucial. These findings should inform the revision of ICG2017, enhancing the evaluation and management of IPMN patients. By implementing these recommendations, clinicians can make more informed decisions, leading to better diagnosis and treatment outcomes for high-risk IPMN cases.

Pancreatic Cyst Size Measurement on Magnetic Resonance Imaging Compared to Pathology

BACKGROUND

While multiple cyst features are evaluated for stratifying pancreatic intraductal papillary mucinous neoplasms (IPMN), cyst size is an important factor that can influence treatment strategies. When magnetic resonance imaging (MRI) is used to evaluate IPMNs, no universally accepted sequence provides optimal size measurements. T2-weighted coronal/axial have been suggested as primary measurement sequences; however, it remains unknown how well these and maximum all-sequence diameter measurements correlate with pathology size. This study aims to compare agreement and bias between IPMN long-axis measurements on seven commonly obtained MRI sequences with pathologic size measurements.

METHODS

This retrospective cohort included surgically resected IPMN cases with preoperative MRI exams. Long-axis diameter tumor measurements and the presence of worrisome features and/orhigh-risk stigmata were noted on all seven MRI sequences. MRI size and pathology agreement and MRI inter-observer agreement involved concordance correlation coefficient (CCC) and intraclass correlation coefficient (ICC), respectively. The presence of worrisome features and high-risk stigmata were compared to the tumor grade using kappa analysis. The Bland-Altman analysis assessed the systematic bias between MRI-size and pathology.

RESULTS

In 52 patients (age 68 ± 13 years, 22 males), MRI sequences produced mean long-axis tumor measurements from 2.45-2.65 cm. The maximum MRI lesion size had a strong agreement with pathology (CCC = 0.82 (95% CI: 0.71-0.89)). The maximum IPMN size was typically observed on the axial T1 arterial post-contrast and MRCP coronal series and overestimated size versus pathology with bias +0.34 cm. The radiologist interobserver agreement reached ICCs 0.74 to 0.91 on the MRI sequences.

CONCLUSION

The maximum MRI IPMN size strongly correlated with but tended to overestimate the length compared to the pathology, potentially related to formalin tissue shrinkage during tissue processing.

Hepatic Steatosis After Partial Pancreatectomy in a Cohort of Patients with Intraductal Papillary Mucinous Neoplasm

Background/Aims

Nonalcoholic fatty liver disease (NAFLD) has been observed in patients after partial pancreatectomy. Previous studies have been performed on oncologic patients who underwent partial pancreatectomy and received adjuvant chemotherapy. By studying a cohort of patients with intraductal papillary mucinous neoplasms (IPMNs) who did not receive chemotherapy, the authors investigate the isolated effect of partial pancreatectomy on the development of fatty liver.

Methods

A retrospective search for patients with pancreatic IPMNs who underwent partial pancreatectomy at an academic center from 2006 to 2014 identified 63 patients, including 42 who had pancreaticoduodenectomy (PD) and 21 who had distal pancreatectomy (DP). Fourteen patients with preoperative hepatic steatosis, diabetes, obesity, on steroid therapy, history of malignancy, or incomplete data were excluded. No patient received chemotherapy. Liver fat signal fraction (LFSF) was computed by the Dixon method using pre- and postoperative in- and out-of-phase MRI.

Results

Of the 49 patients included in the study, 29 (59%) underwent PD and 20 (41%) underwent DP. A total of 17 patients (34%) developed fatty liver after surgery. The entire cohort developed significant weight loss, 72.1 versus 69.4 kg (P < 0.01). Postoperatively, there was significant increase in LFSF, 1.3% versus 9.6% following PD (P < 0.01), and 2.1% versus 9.4% following DP (P = 0.01).

Conclusion

Partial pancreatectomy increases the risk of NAFLD independent of chemotherapy-induced hepatotoxicity. The underlying mechanism remains unclear and possibly related to pancreatic exocrine insufficiency and malnutrition.

Comparison of Clinical and Imaginal Features According to the Pathological Grades of Dysplasia in Branch-Duct Intraductal Papillary Mucinous Neoplasm (BD-IPMN) for Personalized Medicine

Background: In patients with BD-IPMN, surgical indications have been focused on finding malignant lesions (HGD, high-grade dysplasia/IC, invasive carcinoma). The aim of this study was to compare the preoperative factors that distinguish HGD from LGD (low-grade dysplasia) and HGD from IC to find the optimal pathologic target for surgery according to individuals, considering surgical risks and outcomes. Methods: We retrospectively analyzed 232 patients with BD-IPMN diagnosed based on pathology after surgery and preoperative images. The primary outcome was identifying preoperative factors distinguishing HGD from LGD, and HGD from IC. Results: In patients with LGD/HGD, a solid component or an enhancing mural nodule ≥ 5 mm (OR = 9.29; 95% CI: 3.3−54.12; p < 0.000) and thickened/enhancing cyst walls (OR = 6.95; 95% CI: 1.68−33.13; p = 0.008) were associated with HGD. In patients with malignant lesions (HGD/IC), increased serum CA 19-9 (OR = 12.59; 95% CI: 1.81−87.44; p = 0.006) was associated with IC. Conclusions: The predictive factors for HGD were the presence of a solid component or an enhancing mural nodule ≥ 5 mm and thickened/enhancing cyst walls compared with LGD, and if accompanied by increased CA 19-9, it might be necessary to urgently evaluate the lesion due to the possibility of progression to IC. Based on this finding, we need to find HGD as the optimal pathologic target for surgery to improve survival in low-surgical-risk patients, and IC could be assumed to be the optimal pathologic target for surgery in high-surgical-risk patients because of high morbidity and mortality associated with surgery.

Lower Interobserver Reliability for Nondimensional Intracystic Features Among Abdominal Radiologists for Characterizing Intraductal Papillary Mucinous Neoplasms Using Magnetic Resonance Imaging

OBJECTIVES

Current guidelines recommend magnetic resonance imaging (MRI)/magnetic resonance cholangiopancreatography (MRCP) for risk stratification of intraductal papillary mucinous neoplasms (IPMNs). We assessed the interobserver agreement among radiologists in evaluating and risk stratifying IPMNs.

METHODS

This single-center study evaluated 30 patients with IPMNs who had undergone MRI/MRCP, endoscopic ultrasound, and/or surgical resection. Six abdominal radiologists evaluated the MRI/MRCPs to document multiple parameters. The analysis applied Landis and Koch κ interpretation for categorical variables and intraclass correlation coefficient (r) for continuous variables.

RESULTS

Radiologists demonstrated almost perfect agreement for location (κ = 0.81, 95% confidence interval [CI], 0.74-0.87), size (r = 0.95; 95% CI, 0.89-0.98), and main pancreatic duct diameter (r = 0.98; 95% CI, 0.96-0.99). Substantial agreement was observed for communication with the main pancreatic duct (κ = 0.66; 95% CI, 0.57-0.75) and classification of IPMN subtype (κ = 0.77; 95% CI, 0.67-0.86). Presence of intracystic nodules (κ = 0.31; 95% CI, 0.21-0.42) and wall thickening (κ = 0.09; 95% CI, -0.01 to 0.18) reached only fair and slight agreement, respectively.

CONCLUSIONS

Although MRI/MRCP is excellent in the evaluation of spatial aspects, there is lower reliability for nondimensional characteristics of IPMNs. These data support guideline-recommended complementary evaluation of IPMNs with MRI/MRCP and endoscopic ultrasound.

Impact of Antibiotic Prophylaxis on Infection Rate after Endoscopic Ultrasound Through-the-Needle Biopsy of Pancreatic Cysts: A Propensity Score-Matched Study

Background: Despite weak evidence, antibiotic prophylaxis prior to endoscopic ultrasound-guided through-the-needle biopsy (EUS-TTNB) of pancreatic cystic lesions (PCLs) is routinely used in clinical practice. We aim to compare a group of patients treated with antibiotics before EUS-TTNB of PCLs and a group who did not undergo antimicrobial prophylaxis. Methods: Out of 236 patients with pancreatic cystic lesions referred to two high-volume centers between 2016 and 2021, after propensity score matching, two groups were compared: 98 subjects who underwent EUS-TTNB under antibiotic prophylaxis and 49 subjects without prophylaxis. Results: There was no difference in terms of baseline parameters between groups. Final diagnosis was serous cystadenoma in 36.7% of patients in the group not treated with prophylaxis and in 37.7% of patients in the control group, whereas IPMN and mucinous cystadenoma were diagnosed in 3 (6.1%) and 16 (32.6%) versus 6 (6.1%) and 32 (32.6%) patients in the two groups, respectively (p = 0.23). Overall, the adverse event rate was 6.1% in the group not treated with antibiotic prophylaxis and 5.1% in the control group (p = 0.49). Only a single infectious adverse event occurred in each group (p = 0.48). The diagnostic yields were 89.7% and 90.8% in the two groups (p = 0.7), and the diagnostic accuracy rate was 81.6% in both groups (p = 1.0). Conclusions: Prophylactic antibiotics do not seem to influence the risk of infection, and their routine use should be discouraged.

Intraductal Papillary Mucinous Neoplasms: Have IAP Consensus Guidelines Changed our Approach?: Results from a Multi-institutional Study

OBJECTIVE

To evaluate the influence of consensus guidelines on the management of intraductal papillary mucinous neoplasms (IPMN) and the subsequent changes in pathologic outcomes.

BACKGROUND

Over time, multiple guidelines have been developed to identify high-risk IPMN. We hypothesized that the development and implementation of guidelines should have increased the percentage of resected IPMN with high-risk disease.

METHODS

Memorial Sloan-Kettering (MSK), Johns Hopkins (JH), and Massachusetts General Hospital (MGH) databases were queried for resected IPMN (2000-2015). Patients were categorized into main-duct (MD-IPMN) versus branch-duct (BD-IPMN). Guideline-specific radiographic/endoscopic features were recorded. High-risk disease was defined as high-grade dysplasia/carcinoma. Fisher's exact test was used to detect differences between institutions. Logistic regression evaluated differences between time-points [preguidelines (pre-GL, before 2006), Sendai (SCG, 2006-2012), Fukuoka (FCG, after 2012)].

RESULTS

The study included 1210 patients. The percentage of BD-IPMN with ≥1 high-risk radiographic feature differed between centers (MSK 69%, JH 60%, MGH 45%; P < 0.001). In MD-IPMN cohort, the presence of radiographic features such as solid component and main pancreatic duct diameter ≥10 mm also differed (solid component: MSK 38%, JH 30%, MGH 18%; P < 0.001; duct ≥10 mm: MSK 49%, JH 32%, MGH 44%; P < 0.001). The percentage of high-risk disease on pathology, however, was similar between institutions (BD-IPMN: P = 0.36, MD-IPMN: P = 0.48). During the study period, the percentage of BD-IPMN resected with ≥1 high-risk feature increased (52% pre-GL vs 67% FCG; P = 0.005), whereas the percentage of high-risk disease decreased (pre-GL vs FCG: 30% vs 20%). For MD-IPMN, there was not a clear trend towards guideline adherence, and the rate of high-risk disease was similar over the time (pre-GL vs FCG: 69% vs 67%; P = 0.63).

CONCLUSION

Surgical management of IPMN based on radiographic criteria is variable between institutions, with similar percentages of high-risk disease. Over the 15-year study period, the rate of BD-IPMN resected with high-risk radiographic features increased; however, the rate of high-risk disease decreased. Better predictors are needed.

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas: recommendations for Standardized Imaging and Reporting from the Society of Abdominal Radiology IPMN disease focused panel

There have been many publications detailing imaging features of malignant transformation of intraductal papillary mucinous neoplasms (IPMN), management and recommendations for imaging follow-up of diagnosed or presumed IPMN. However, there is no consensus on several practical aspects of imaging IPMN that could serve as a clinical guide for radiologists and enable future data mining for research. These aspects include how to measure IPMN, define reporting terminology, standardize reporting and unify guidelines for surveillance. The Society of Abdominal Radiology (SAR) created multiple Disease-Focused Panels (DFP) comprised multidisciplinary panel members who focus on a particular disease, with the goal to develop ways for radiologists to improve patient care, education, and research. DFP members met to identify the current controversies and limitations of imaging pancreatic IPMN. This paper aims to provide a practical review of the key imaging characteristics of IPMN for trainees and practicing radiologists, to guide uniformity of performance and interpretation of surveillance imaging studies, and to improve communication with clinicians by providing a lexicon and reporting template based on the experience of the SAR-DFP panel members.

Nomogram for the Prediction of High-Grade Dysplasia and Invasive Carcinoma in Patients With Intraductal Papillary Mucinous Neoplasms of the Pancreas Based on Variables of Noninvasive Examination

Intraductal papillary mucinous neoplasms (IPMNs) are a heterogeneous group of neoplasms and represent the most common identifiable precursor lesions of pancreatic cancer. Clinical decision-making of the risk for malignant disease, including high-grade dysplasia and invasive carcinoma, is challenging. Moreover, discordance on the indication for resection exists between the contemporary guidelines. Furthermore, most of the current nomogram models for predicting malignant disease depend on endoscopic ultrasonography to evaluate the precise size of mural nodules. Thus, this study aimed to propose a model to predict malignant disease using variables from a noninvasive examination. We evaluated patients who underwent resection of pathologically confirmed IPMNs between November 2010 and December 2018 and had preoperative clinical data available for review. Based on binary multivariable logistic regression analysis, we devised a nomogram model to predict malignant IPMNs. The area under the receiver operating characteristics curve (AUC) was used to evaluate the discrimination power of the model. Of the 333 patients who underwent resection of IPMNs, 198 (59.5%) had benign and 135 (40.5%) had malignant IPMNs. Multivariable logistic regression analysis showed that cyst size, cyst location, cyst wall enhancement, multicystic lesion, diameter of main pancreatic duct, neutrophil-to-lymphocyte ratio, serum carbohydrate antigen 19-9, and carcinoembryonic antigen were significantly associated with malignancy. The nomogram, constructed based on these variables, showed excellent discrimination power with an AUC of 0.859 (95% CI: 0.818–0.900, P < 0.001). In conclusion, we have developed a nomogram consisting of a combination of cross-sectional imaging features and blood markers, variables that can readily be obtained by noninvasive examinations during the surveillance period, which can distinguish benign from malignant IPMNs. Nevertheless, external validation is warranted.

Radiomic nomogram based on MRI to predict grade of branching type intraductal papillary mucinous neoplasms of the pancreas: a multicenter study

Background

Accurate diagnosis of high-grade branching type intraductal papillary mucinous neoplasms (BD-IPMNs) is challenging in clinical setting. We aimed to construct and validate a nomogram combining clinical characteristics and radiomic features for the preoperative prediction of low and high-grade in BD-IPMNs.

Methods

Two hundred and two patients from three medical centers were enrolled. The high-grade BD-IPMN group comprised patients with high-grade dysplasia and invasive carcinoma in BD-IPMN (n = 50). The training cohort comprised patients from the first medical center (n = 103), and the external independent validation cohorts comprised patients from the second and third medical centers (n = 48 and 51). Within 3 months prior to surgery, all patients were subjected to magnetic resonance examination. The volume of interest was delineated on T1-weighted (T1-w) imaging, T2-weighted (T2-w) imaging, and contrast-enhanced T1-weighted (CET1-w) imaging, respectively, on each tumor slice. Quantitative image features were extracted using MITK software (G.E.). The Mann-Whitney U test or independent-sample t-test, and LASSO regression, were applied for data dimension reduction, after which a radiomic signature was constructed for grade assessment. Based on the training cohort, we developed a combined nomogram model incorporating clinical variables and the radiomic signature. Decision curve analysis (DCA), a receiver operating characteristic curve (ROC), a calibration curve, and the area under the ROC curve (AUC) were used to evaluate the utility of the constructed model based on the external independent validation cohorts.

Results

To predict tumor grade, we developed a nine-feature-combined radiomic signature. For the radiomic signature, the AUC values of high-grade disease were 0.836 in the training cohort, 0.811 in external validation cohort 1, and 0.822 in external validation cohort 2. The CA19–9 level and main pancreatic duct size were identified as independent parameters of high-grade of BD-IPMNs using multivariate logistic regression analysis. The CA19–9 level and main pancreatic duct size were then used to construct the radiomic nomogram. Using the radiomic nomogram, the high-grade disease-associated AUC values were 0.903 (training cohort), 0.884 (external validation cohort 1), and 0.876 (external validation cohort 2). The clinical utility of the developed nomogram was verified using the calibration curve and DCA.

Conclusions

The developed radiomic nomogram model could effectively distinguish high-grade patients with BD-IPMNs preoperatively. This preoperative identification might improve treatment methods and promote personalized therapy in patients with BD-IPMNs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-021-00395-6.

MRI of the Pancreas

MRI has played a critical role in the evaluation of patients with pancreatic pathologies, from screening of patients at high risk for pancreatic cancer to the evaluation of pancreatic cysts and indeterminate pancreatic lesions. The high mortality associated with pancreatic adenocarcinomas has spurred much interest in developing effective screening tools, with MRI using magnetic resonance cholangiopancreatography (MRCP) playing a central role in the hopes of identifying cancers at earlier stages amenable to curative resection. Ongoing efforts to improve the resolution and robustness of imaging of the pancreas using MRI may thus one day reduce the mortality of this deadly disease. However, the increasing use of cross-sectional imaging has also generated a concomitant clinical conundrum: How to manage incidental pancreatic cystic lesions that are found in over a quarter of patients who undergo MRCP. Efforts to improve the specificity of MRCP for patients with pancreatic cysts and with indeterminate pancreatic masses may be achieved with continued technical advances in MRI, including diffusion-weighted and T₁ -weighted dynamic contrast-enhanced MRI. However, developments in quantitative MRI of the pancreas remain challenging, due to the small size of the pancreas and its upper abdominal location, adjacent to bowel and below the diaphragm. Further research is needed to improve MRI of the pancreas as a clinical tool, to positively affect the lives of patients with pancreatic abnormalities. This review focuses on various MR techniques such as MRCP, quantitative imaging, and dynamic contrast-enhanced imaging and their clinical applicability in the imaging of the pancreas, with an emphasis on pancreatic malignant and premalignant lesions. Level of Evidence 5 Technical Efficacy Stage 3 J. MAGN. RESON. IMAGING 2021;53:347-359.

Invasive Intraductal Papillary Mucinous Neoplasms: CT Features of Colloid Carcinoma Versus Tubular Adenocarcinoma of the Pancreas

OBJECTIVE. The purpose of this study is to compare the CT features of colloid carcinoma and tubular adenocarcinoma of the pancreas arising in association with intraductal papillary mucinous neoplasms (IPMNs). MATERIALS AND METHODS. The preoperative CT images of 85 patients with histopathologically proven IPMNs and associated invasive adenocarcinoma located next to each other were retrospectively reviewed. Twenty-nine patients (34.1%; 19 men and 10 women; mean [± SD] age, 68.0 ± 9.5 years) had invasive colloid carcinoma, and 56 patients (65.9%; 31 men and 25 women; mean age, 70.8 ± 10.6 years) had invasive tubular adenocarcinoma. We compared the following CT features between the two groups: IPMN type, main pancreatic duct (MPD) and common bile duct diameters, diameter and characteristics of the largest cystic lesion for branch duct and mixed-type IPMNs, presence of an extracystic or extraductal solid mass next to the cystic lesion or MPD, morphologic features of the upstream MPD in relation to the cystic lesion or solid mass, and presence of a fistula to the adjacent organs. RESULTS. An MPD size of 9.5 mm or greater, a largest cystic lesion diameter of 28 mm or greater, location in the head or neck, septation, calcification, presence of a mural nodule(s) within a cystic lesion or MPD, and presence of a fistula were all more commonly associated with colloid carcinoma. In contrast, presence of an extracystic or extraductal solid mass and an abrupt change in the caliber of the dilated MPD were associated with tubular adenocarcinoma. The best CT feature for differentiating between the two groups was the morphologic features of the upstream MPD in relation to the cystic lesion or solid mass (sensitivity, 81.3%; specificity, 92.3%). CONCLUSION. Preoperative CT is helpful in differentiating two types of invasive carcinoma arising in association with IPMNs. These findings are clinically important because prognosis is better for colloid carcinoma than for tubular adenocarcinoma.

Statins decrease the risk of acute pancreatitis after endoscopic ultrasound fine-needle aspiration of pancreatic cysts

BACKGROUND

Basic and clinical studies suggest that statins may prevent and even ameliorate acute pancreatitis. The present study was to evaluate whether statin decreases the risk of acute pancreatitis in patients undergoing endoscopic ultrasound-guided fine-needle aspiration of pancreatic cysts.

METHODS

Out of 456 patients with pancreatic cysts referred to our center between 2006 and 2018, 365 were finally included in analyses: 86 were treated with statins and 279 were not at the time of endoscopic ultrasound fine-needle aspiration. We compared the acute pancreatitis incidence between the two groups, and we also compared other complications such as bleeding and infections.

RESULTS

Median age was 64 years [interquartile range (IQR) 62-69] and median cyst size was 24 mm (IQR, 21-29). The most frequent histology was intraductal papillary mucinous neoplasm (45.3% and 42.3% in the two groups, respectively; P = 0.98). All 13 patients experiencing post-endoscopic ultrasound acute pancreatitis were from the control group (4.7%), of which 3 were classified as severe pancreatitis. None of statin users developed post-procedural acute pancreatitis (odds ratio: 0.15; 95% confidence interval: 0.03-0.98; P = 0.03). No difference was registered with regard to severe pancreatitis and other complications.

CONCLUSIONS

Statins exert a beneficial role in preventing acute pancreatitis in patients with pancreatic cysts undergoing endoscopic ultrasound-guided fine-needle aspiration. If confirmed in prospective trials, our findings may pave the way to an extensive use of statins as prophylactic agents in pancreatic interventional endoscopy.

Antibiotics Do Not Decrease the Rate of Infection After Endoscopic Ultrasound Fine-Needle Aspiration of Pancreatic Cysts

BACKGROUND

In spite of the weak evidence, antibiotic prophylaxis prior to endoscopic ultrasound-guided fine-needle aspiration of pancreatic cystic lesions is routinely used in the clinical practice.

AIMS

To compare a group of patients treated with antibiotics before fine-needle aspiration of pancreatic cystic lesions and a group who did not undergo antimicrobial prophylaxis.

METHODS

Out of 335 patients with suspected pancreatic cystic lesions referred to our center between 2006 and 2018, after propensity score matching two groups were compared: 135 subjects who underwent endoscopic ultrasound fine-needle aspiration under antibiotic prophylaxis and 135 treated with no antimicrobial agents. Primary outcome was infection rate; secondary endpoints included other complications or antibiotic-related adverse events.

RESULTS

Median age was 64 (interquartile range 61-68) and median cyst size was 24 mm (22-28), with no difference between groups. Overall, 10 adverse events (7.1%) of which 2 serious (1.4%) were observed in the antibiotic group and 8 (5.8%) of which 1 (0.7%) serious in the non-antibiotic group. Cyst infection was observed in 2 patients (1.4%) in the antibiotic group and 3 patients (2.2%) in the other cohort (p = 0.65).

CONCLUSIONS

Prophylactic antibiotics do not seem to substantially reduce this risk of infection, and their routine use should be abandoned.

Preoperative risk prediction for intraductal papillary mucinous neoplasms by quantitative CT image analysis

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) are radiographically identifiable potential precursor lesions of pancreatic adenocarcinoma. While resection is recommended when main duct dilation is present, management of branch duct IPMN (BD-IPMN) remains controversial. This study sought to evaluate whether preoperative quantitative imaging features of BD-IPMNs could distinguish low-risk disease (low- and intermediate-grade dysplasia) from high-risk disease (high-grade dysplasia and invasive carcinoma).

METHODS

Patients who underwent resection between 2005 and 2015 with pathologically proven BD-IPMN and a preoperative CT scan were included in the study. Quantitative image features were extracted using texture analysis and a novel quantitative mural nodularity feature developed for the study. Significant features on univariate analysis were combined with clinical variables to build a multivariate prediction model.

RESULTS

Within the study group of 103 patients, 76 (74%) had low-risk disease and 27 (26%) had high-risk disease. Quantitative imaging features were prognostic of low-vs. high-risk disease. The model based only on clinical variables achieved an AUC of 0.67 and 0.79 with the addition of quantitative imaging features.

CONCLUSION

Quantitative image analysis of BD-IPMNs is a novel method that may enable risk stratification. External validation may provide a reliable non-invasive prognostic tool for clinicians.

CT radiomics to predict high-risk intraductal papillary mucinous neoplasms of the pancreas

PURPOSE

Intraductal papillary mucinous neoplasms (IPMNs) are radiographically visible precursor lesions of pancreatic cancer. Despite standard criteria for assessing risk, only 18% of cysts are malignant at resection. Thus, a large number of patients undergo unnecessary invasive surgery for benign disease. The ability to identify IPMNs with low or high risk of transforming into invasive cancer would optimize patient selection and improve surgical decision-making. The purpose of this study was to investigate quantitative CT imaging features as markers for objective assessment of IPMN risk.

METHODS

This retrospective study analyzed pancreatic cyst and parenchyma regions extracted from CT scans in 103 patients to predict IPMN risk. Patients who underwent resection between 2005 and 2015 with pathologically proven branch duct (BD)-IPMN and a preoperative CT scan were included in the study. Expert pathologists categorized IPMNs as low or high risk following resection as part of routine clinical care. We extracted new radiographically inspired features as well as standard texture features and designed prediction models for the categorization of high- and low-risk IPMNs. Five clinical variables were also combined with imaging features to design prediction models.

RESULTS

Using images from 103 patients and tenfold cross-validation technique, the novel radiographically inspired imaging features achieved an area under the receiver operating characteristic curve (AUC) of 0.77, demonstrating their predictive power. The combination of these features with clinical variables obtained the best performance (AUC = 0.81).

CONCLUSION

The present study demonstrates that features extracted from pretreatment CT images can predict the risk of IPMN. Development of a preoperative model to discriminate between low-risk and high-risk IPMN will improve surgical decision-making.

Radiological Workup of Cystic Neoplasms of the Pancreas

Pancreatic cystic lesions are being detected with increasing frequency because of increased use and improved quality of cross-sectional imaging techniques. Pancreatic cystic lesions encompass non-neoplastic lesions (such as pancreatitis-related collections) and neoplastic tumors. Common cystic pancreatic neoplasms include serous cystadenomas, mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, and solid pseudopapillary tumors. These cystic pancreatic neoplasms may have typical morphology, but at times show overlapping imaging features on cross-sectional examinations. This article reviews the classical and atypical imaging features of commonly encountered cystic pancreatic neoplasms and presents the limitations of current cross-sectional imaging techniques in accurately classifying pancreatic cystic lesions.

Intraductal Papillary Mucinous Neoplasm of the Pancreas as the Main Focus for Early Detection of Pancreatic Adenocarcinoma

For early detection of pancreatic cancer, interests are now focused on the detection of high-risk individuals to undergo screening examinations. Intraductal papillary mucinous neoplasm (IPMN) is a unique dual precursor of pancreatic cancer, characterized by progression to invasive cancer and the development of pancreatic adenocarcinoma either concomitantly (synchronous occurrence) or even after resection of IPMN (metachronous occurrence). Careful examination and surveillance of patients with IPMN may therefore lead to early detection of pancreatic cancer. By reviewing only reports describing detailed breakdown of the morphological types of IPMN and numbers of patients with noninvasive and invasive carcinoma in each type, the rough frequencies of noninvasive carcinoma in main duct IPMNs and branch duct IPMNs (BD-IPMNs) are 20% and 10%, respectively, and those of invasive carcinoma are 40% and 13%, respectively. Roughly 5% of all patients with IPMN had concomitant adenocarcinoma. The real frequency of carcinoma in BD-IPMNs would be far lower because most patients with small asymptomatic BD-IPMNs do not undergo resection. Intraductal papillary mucinous neoplasm can be the main focus for early detection of pancreatic cancer to achieve favorable prognosis after surgical resection. The optimal protocol for surveillance and method for early detection of pancreatic cancer are to be determined.

Development and Validation of a Multi-institutional Preoperative Nomogram for Predicting Grade of Dysplasia in Intraductal Papillary Mucinous Neoplasms (IPMNs) of the Pancreas: A Report from The Pancreatic Surgery Consortium

OBJECTIVE

Previous nomogram models for patients undergoing resection of intraductal papillary mucinous neoplasms (IPMNs) have been relatively small single-institutional series. Our objective was to improve upon these studies by developing and independently validating a new model using a large multiinstitutional dataset.

SUMMARY BACKGROUND DATA

IPMNs represent the most common radiographically identifiable precursor lesions of pancreatic cancer. They are a heterogenous group of neoplasms in which more accurate markers of high-grade dysplasia or early invasive carcinoma could help avoid unnecessary surgery in 1 case and support potentially curative intervention (resection) in another.

METHODS

Prospectively maintained databases from 3 institutions were queried for patients who had undergone resection of IPMNs between 2005 and 2015. Patients were separated into main duct [main and mixed-type (MD)] and branch duct (BD) types based on preoperative imaging. Logistic regression modeling was used on a training subset to develop 2 independent nomograms (MD and BD) to predict low-risk (low- or intermediate-grade dysplasia) or high-risk (high-grade dysplasia or invasive carcinoma) disease. Model performance was then evaluated using an independent validation set.

RESULTS

We identified 1028 patients who underwent resection for IPMNs [MD: n = 454 (44%), BD: n = 574 (56%)] during the 10-year study period. High-risk disease was present in 487 patients (47%). Patients with high-risk disease comprised 71% and 29% of MD and BD groups, respectively (P <0.0001). MD and BD nomograms were developed on the training set [70% of total (n = 720); MD: n = 318, BD: n = 402] and validated on the test set [30% (n = 308); MD: n = 136, BD: n = 172]. The presence of jaundice was almost exclusively associated with high-risk disease (57 of 58 patients, 98%). Cyst size >3.0 cm, solid component/mural nodule, pain symptoms, and weight loss were significantly associated with high-risk disease. C-indices were 0.82 and 0.81 on training and independent validation sets, respectively; Brier scores were 0.173 and 0.175, respectively.

CONCLUSIONS

For patients with suspected IPMNs, we present an independently validated model for the prediction of high-risk disease.

My Treatment Approach: Pancreatic Cysts

Our treatment approach for either symptomatic or incidentally found pancreatic cysts continues to improve. The true incidence of pancreatic cysts is not known, and pancreatic cystic neoplasms, especially intraductal papillary mucinous neoplasms, are currently most commonly diagnosed and resected. This is a result of increasing awareness, widespread availability of imaging, and better understanding of the nature of pancreatic cysts as well. Recent studies on molecular analysis and devices such as microbiopsy forceps help us better define and select the treatment approach to alleviate symptoms and to prevent malignant tumors while avoiding unnecessary surgery.

Comparative radiological pathological study of biliary intraductal tubulopapillary neoplasm and biliary intraductal papillary mucinous neoplasm

PURPOSE

Biliary tract intraductal tubulopapillary neoplasms (BT-ITPNs) and intraductal papillary mucinous neoplasms (BT-IPMNs) are rare and poorly described. Herein, we examined the magnetic resonance imaging (MRI) features of BT-ITPNs and BT-IPMNs and correlated them with key gross and microscopic pathological findings.

METHODS

We retrospectively identified five patients with definitive pathological findings of BT-ITPN and available diagnostic MRI findings. Key MRI features were correlated to the gross and microscopic pathology and compared to those of BT-IPMNs (19 patients).

RESULTS

All BT-ITPNs showed ductal dilatation and visible intraductal soft tissue with peribiliary liver parenchyma enhancement. One BT-ITPN patient had synchronous lung metastases, and another showed rapid tumor growth rate. The intraductal soft tissue proportion of BT-ITPNs was significantly more than that of BT-IPMNs (p < 0.05). CA-199 level was elevated in 60% of BT-ITPN cases. The overall combined 1-year and 3-year survival rates in the BT-ITPN group was 100% and 40%, and in the BT-IPMN group was 100% and 58%, respectively. A high intraductal soft tissue proportion, a lack of intraluminal mucin, and immunohistochemical absence of MUC5AC are radiological and pathological characteristics that differentiate BT-ITPN from BT-IPMN.

CONCLUSIONS

Although rare, BT-ITPN should be suspected when solid intraductal soft tissue and peribiliary liver parenchyma enhancement are present, particularly if the bile duct upstream and downstream of the lesion have a normal diameter, without mucin. Owing to the aggressive nature of the tumor, recognition of these features may indicate the need for more aggressive treatment in selected patients.

Neutrophil-to-lymphocyte Ratio is a Predictive Marker for Invasive Malignancy in Intraductal Papillary Mucinous Neoplasms of the Pancreas

OBJECTIVE

To evaluate the correlation between neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) values, and the presence of invasive carcinoma in patients with intraductal papillary mucinous neoplasm (IPMN).

BACKGROUND

NLR and (PLR) are inflammatory markers that have been associated with overall survival in patients with invasive malignancies, including pancreatic cancer.

METHODS

We retrospectively reviewed 272 patients who underwent surgical resection for histologically confirmed IPMN from January 1997 to July 2015. NLR and PLR were calculated and coevaluated with additional demographic, clinical, and imaging data for possible correlation with IPMN-associated carcinoma in the form of a predictive nomogram.

RESULTS

NLR and PLR were significantly elevated in patients with IPMN-associated invasive carcinoma (P < 0.001). In the multivariate analysis, NLR value higher than 4 (P < 0.001), IPMN cyst of size more than 3 cm (P < 0.001), presence of enhanced solid component (P = 0.014), main pancreatic duct dilatation of more than 5 mm (P < 0.001), and jaundice (P < 0.001) were statistically significant variables. The developed statistical model has a c-index of 0.895. Implementation of the statistically significant variables in a predictive nomogram provided a reliable point system for estimating the presence of IPMN-associated invasive carcinoma.

CONCLUSIONS

NLR is an independent predictive marker for the presence of IPMN-associated invasive carcinoma. Further prospective studies are needed to assess the predictive ability of NLR and how it can be applied in the clinical setting.

Pancreatic Cysts and Guidelines

Pancreatic cysts, especially incidental asymptomatic ones seen on noninvasive imaging such as CT or MR imaging, remain a clinical challenge. The etiology of such cysts may range from benign cysts without any malignant potential such as pancreatic pseudocysts and serous cystadenomas to premalignant or frankly malignant cysts such as mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, cystic degeneration associated with solid tumors such as pancreatic ductal adenocarcinoma or pancreatic endocrine neoplasms, and solid pseudopapillary neoplasms. The clinical challenge in 2017 is to accurately preoperatively diagnose them and their malignant potential before deciding about surgery, surveillance or doing nothing. This review will focus on the currently available clinical guidelines for doing so.

Diagnostic performance and imaging features for predicting the malignant potential of intraductal papillary mucinous neoplasm of the pancreas: a comparison of EUS, contrast-enhanced CT and MRI

PURPOSE

To compare diagnostic performance for prediction of malignant potential in IPMNs between EUS, contrast-enhanced CT and MRI.

MATERIALS AND METHODS

76 patients with IPMN (benign = 37, malignant = 39) underwent EUS, contrast-enhanced CT, and MRI. EUS was analyzed based on formal reports and contrast-enhanced CT and MRI were retrospectively analyzed by two radiologists according to the consensus guidelines 2012. Diagnostic performance and imaging features of malignant IPMNs were analyzed using ROC analysis and multivariate analyses.

RESULTS

Diagnostic performance of contrast-enhanced CT (AUC = 0.792 in R1, 0.830 in R2), MRI (AUC = 0.742 in R1, 0.776 in R2), and EUS (AUC = 0.733) for predicting malignant IPMNs were comparable without significant difference (p > 0.05). In multivariable analysis, enhancing solid component in contrast-enhanced CT and MRI and mural nodule in EUS (OR 1.8 in CT, 1.36 in MRI, 1.47 in EUS), MPD diameter ≥ 10 mm (OR 1.3 in CT, 1.4 in MRI, 1.66 in EUS), MPD diameter of 5-9 mm (OR 1.23 in CT, 1.31 in MRI), and thickened septa or wall (OR 1.3 in CT and MRI) were significant variables (p < 0.05). Interobserver agreement of thickened cyst septa or wall (k = 0.579-0.617) and abrupt caliber change of MPD (k = 0.689-0.788) was lower than other variables (k > 0.80).

CONCLUSION

Diagnostic performance of contrast-enhanced CT, MRI, and EUS for predicting malignant IPMNs was comparable with each modalities without significant difference.

Imaging modalities for characterising focal pancreatic lesions

BACKGROUND

Increasing numbers of incidental pancreatic lesions are being detected each year. Accurate characterisation of pancreatic lesions into benign, precancerous, and cancer masses is crucial in deciding whether to use treatment or surveillance. Distinguishing benign lesions from precancerous and cancerous lesions can prevent patients from undergoing unnecessary major surgery. Despite the importance of accurately classifying pancreatic lesions, there is no clear algorithm for management of focal pancreatic lesions.

OBJECTIVES

To determine and compare the diagnostic accuracy of various imaging modalities in detecting cancerous and precancerous lesions in people with focal pancreatic lesions.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, and Science Citation Index until 19 July 2016. We searched the references of included studies to identify further studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We planned to include studies reporting cross-sectional information on the index test (CT (computed tomography), MRI (magnetic resonance imaging), PET (positron emission tomography), EUS (endoscopic ultrasound), EUS elastography, and EUS-guided biopsy or FNA (fine-needle aspiration)) and reference standard (confirmation of the nature of the lesion was obtained by histopathological examination of the entire lesion by surgical excision, or histopathological examination for confirmation of precancer or cancer by biopsy and clinical follow-up of at least six months in people with negative index tests) in people with pancreatic lesions irrespective of language or publication status or whether the data were collected prospectively or retrospectively.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched the references to identify relevant studies and extracted the data. We planned to use the bivariate analysis to calculate the summary sensitivity and specificity with their 95% confidence intervals and the hierarchical summary receiver operating characteristic (HSROC) to compare the tests and assess heterogeneity, but used simpler models (such as univariate random-effects model and univariate fixed-effect model) for combining studies when appropriate because of the sparse data. We were unable to compare the diagnostic performance of the tests using formal statistical methods because of sparse data.

MAIN RESULTS

We included 54 studies involving a total of 3,196 participants evaluating the diagnostic accuracy of various index tests. In these 54 studies, eight different target conditions were identified with different final diagnoses constituting benign, precancerous, and cancerous lesions. None of the studies was of high methodological quality. None of the comparisons in which single studies were included was of sufficiently high methodological quality to warrant highlighting of the results. For differentiation of cancerous lesions from benign or precancerous lesions, we identified only one study per index test. The second analysis, of studies differentiating cancerous versus benign lesions, provided three tests in which meta-analysis could be performed. The sensitivities and specificities for diagnosing cancer were: EUS-FNA: sensitivity 0.79 (95% confidence interval (CI) 0.07 to 1.00), specificity 1.00 (95% CI 0.91 to 1.00); EUS: sensitivity 0.95 (95% CI 0.84 to 0.99), specificity 0.53 (95% CI 0.31 to 0.74); PET: sensitivity 0.92 (95% CI 0.80 to 0.97), specificity 0.65 (95% CI 0.39 to 0.84). The third analysis, of studies differentiating precancerous or cancerous lesions from benign lesions, only provided one test (EUS-FNA) in which meta-analysis was performed. EUS-FNA had moderate sensitivity for diagnosing precancerous or cancerous lesions (sensitivity 0.73 (95% CI 0.01 to 1.00) and high specificity 0.94 (95% CI 0.15 to 1.00), the extremely wide confidence intervals reflecting the heterogeneity between the studies). The fourth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (dysplasia) provided three tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing invasive carcinoma were: CT: sensitivity 0.72 (95% CI 0.50 to 0.87), specificity 0.92 (95% CI 0.81 to 0.97); EUS: sensitivity 0.78 (95% CI 0.44 to 0.94), specificity 0.91 (95% CI 0.61 to 0.98); EUS-FNA: sensitivity 0.66 (95% CI 0.03 to 0.99), specificity 0.92 (95% CI 0.73 to 0.98). The fifth analysis, of studies differentiating cancerous (high-grade dysplasia or invasive carcinoma) versus precancerous (low- or intermediate-grade dysplasia) provided six tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing cancer (high-grade dysplasia or invasive carcinoma) were: CT: sensitivity 0.87 (95% CI 0.00 to 1.00), specificity 0.96 (95% CI 0.00 to 1.00); EUS: sensitivity 0.86 (95% CI 0.74 to 0.92), specificity 0.91 (95% CI 0.83 to 0.96); EUS-FNA: sensitivity 0.47 (95% CI 0.24 to 0.70), specificity 0.91 (95% CI 0.32 to 1.00); EUS-FNA carcinoembryonic antigen 200 ng/mL: sensitivity 0.58 (95% CI 0.28 to 0.83), specificity 0.51 (95% CI 0.19 to 0.81); MRI: sensitivity 0.69 (95% CI 0.44 to 0.86), specificity 0.93 (95% CI 0.43 to 1.00); PET: sensitivity 0.90 (95% CI 0.79 to 0.96), specificity 0.94 (95% CI 0.81 to 0.99). The sixth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (low-grade dysplasia) provided no tests in which meta-analysis was performed. The seventh analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) provided two tests in which meta-analysis was performed. The sensitivity and specificity for diagnosing cancer were: CT: sensitivity 0.83 (95% CI 0.68 to 0.92), specificity 0.83 (95% CI 0.64 to 0.93) and MRI: sensitivity 0.80 (95% CI 0.58 to 0.92), specificity 0.81 (95% CI 0.53 to 0.95), respectively. The eighth analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) or benign lesions provided no test in which meta-analysis was performed.There were no major alterations in the subgroup analysis of cystic pancreatic focal lesions (42 studies; 2086 participants). None of the included studies evaluated EUS elastography or sequential testing.

AUTHORS' CONCLUSIONS

We were unable to arrive at any firm conclusions because of the differences in the way that study authors classified focal pancreatic lesions into cancerous, precancerous, and benign lesions; the inclusion of few studies with wide confidence intervals for each comparison; poor methodological quality in the studies; and heterogeneity in the estimates within comparisons.

Management of branch-duct intraductal papillary mucinous neoplasms: a large single-center study to assess predictors of malignancy and long-term outcomes

BACKGROUND AND AIMS

Management of branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) remains challenging. We determined factors associated with malignancy in BD-IPMNs and long-term outcomes.

METHODS

This retrospective cohort study included all patients with established BD-IPMNs by the International Consensus Guidelines (ICG) 2012 and/or pathologically confirmed BD-IPMNs in a tertiary care referral center between 2001 and 2013. Main outcome measures were the association between high-risk stigmata (HRS)/worrisome features (WFs) of the ICG 2012 and malignant BD-IPMNs, performance characteristics of EUS-FNA for the diagnosis of malignant BD-IPMNs, and recurrence and long-term outcomes of BD-IPMN patients undergoing surgery or imaging surveillance.

RESULTS

Of 364 BD-IPMN patients, 229 underwent imaging surveillance and 135 underwent surgery. Among the 135 resected BD-IPMNs, HRS/WFs on CT/magnetic resonance imaging (MRI) were similar between the benign and malignant groups, but main pancreatic duct (MPD) dilation (5-9 mm) was more frequently identified in malignant lesions. On EUS-FNA, mural nodules, MPD features suspicious for involvement, and suspicious/positive malignant cytology were more frequently detected in the malignant group with a sensitivity, specificity, and accuracy of 33%, 94%, and 86%; 42%, 91%, and 83%; and 33% 91%, and 82%, respectively. Mural nodules identified by EUS were missed by CT/MRI in 28% in the malignant group. Patients with malignant lesions had a higher risk of any IPMN recurrence during a mean follow-up period of 131 months (P = .01).

CONCLUSIONS

Among HRS and WFs of the ICG 2012, an MPD size of 5 to 9 mm on CT/MRI was associated with malignant BD-IPMNs. EUS features including mural nodules, MPD features suspicious for involvement, and suspicious/malignant cytology were accurate and highly specific for malignant BD-IPMNs. Our study highlights the incremental value of EUS-FNA over imaging in identifying malignant BD-IPMNs, particularly in patients without WFs and those with smaller cysts. Benign IPMN recurrence was observed in some patients up to 8 years after resection.

Imaging comparison of tubular and colloid pancreatic adenocarcinoma arising from intraductal papillary mucinous neoplasm on multidetector CT

PURPOSE

This study aims to compare tubular pancreatic ductal adenocarcinoma (tPDAC) and colloid subtype pancreatic ductal adenocarcinoma (cPDAC) associated with intraductal papillary mucinous neoplasms (IPMNs) on computed tomography.

METHODS

An institutional review board-approved retrospective study included patients with either IPMN tPDAC or cPDAC. Enhancing mural nodules (MN), solid component (SC), main pancreatic duct (MPD) diameter, and abrupt change in MPD caliber were evaluated.

RESULTS

A total of 22 patients with cPDAC and 17 patients with tPDAC showed no significant difference in MPD size. MN and SC were seen in cPDAC/tPDAC in 55%/18% and 9%/53%, respectively. Abrupt change in MPD caliber was seen in cPDAC/tPDAC at 18%/59%.

CONCLUSION

cPDAC and tPDAC differ in the frequency of MN, SC, and changes in MPD caliber.

Free-Breathing Radial 3D Fat-Suppressed T1-Weighted Gradient-Echo Sequence for Contrast-Enhanced Pediatric Spinal Imaging: Comparison With T1-Weighted Turbo Spin-Echo Sequence

OBJECTIVE

The purpose of this study was to compare free-breathing radially sampled 3D T1-weighted gradient-echo acquisitions (radial volumetric interpolated breath-hold examination [VIBE]) with a T1-weighted turbo spin-echo (TSE) sequence for contrast-enhanced spinal imaging of children with CNS tumors.

MATERIALS AND METHODS

Twenty-eight consecutively registered children with CNS tumors underwent evaluation of leptomeningeal seeding with 1.5-T MRI that included both radial VIBE and T1-weighted TSE sequences. For qualitative analysis, overall image quality; presence of motion, CSF flow, and radial artifacts; and lesion conspicuity were retrospectively assessed with scoring systems. The signal-intensity uniformity of each sequence was evaluated for quantitative comparison. The acquisition times for each sequence were compared.

RESULTS

Images obtained with the radial VIBE sequence had a higher overall image quality score than did T1-weighted TSE images (3.61 ± 0.73 vs 2.80 ± 0.69, p < 0.001) and lower motion artifact (0.82 ± 0.43 vs 1.29 ± 0.56, p = 0.001) and CSF flow artifact (0 vs 1.68 ± 0.67, p < 0.001) scores. Radial artifacts were found only on radial VIBE images (1.36 ± 0.31 vs 0, p < 0.001). In 13 patients with spinal seeding nodules, radial VIBE images showed greater lesion conspicuity than did T1-weighted TSE images (4.23 ± 0.52 vs 2.47 ± 0.57, p = 0.005). Radial VIBE images had diminished signal-intensity variation compared with T1-weighted TSE images in air, spine, and muscle (p < 0.01). The mean acquisition times were not significantly different between the two sequences (p = 0.117).

CONCLUSION

For pediatric spinal imaging, radial VIBE images had better image quality and lesion conspicuity and fewer CSF and respiratory motion artifacts than did T1-weighted TSE images in a similar acquisition time.

Measurement of pancreatic cystic lesions on magnetic resonance imaging: efficacy of standards in reducing inter-observer variability

PURPOSE

The purpose of this study is to assess inter-observer variability in the measurement of pancreatic cystic lesions with MRI and to determine the impact of measurement standards.

MATERIALS AND METHODS

In this IRB-approved, HIPAA-compliant study with waiver of informed consent, 144 MRI examinations, containing pancreatic cystic lesions measuring between 5 and 35 mm, were reviewed independently by two radiology attendings and two abdominal imaging fellows. Measurements were repeated by the same reviewers 12 weeks later after the introduction of measurement standards. Results were analyzed using within-subject standard deviation, intraclass correlation coefficient, and kappa.

RESULTS

Prior to standardization, the within-subject standard deviation, showing measurement variability in each cyst, was 4.0 mm, which was reduced to 3.3 mm after introduction of measurement standards (p < 0.01). Overall inter-observer agreement, kappa, improved from 0.59 to 0.65 (p = 0.04). The frequency of all four reviewers agreeing on size category increased from 51% to 60%. The intraclass correlation coefficient increased from 0.81 to 0.86.

CONCLUSIONS

There is significant and frequent inter-observer variability in the measurement of pancreatic cystic lesions with MRI which could affect clinical management. Implementation of measurement standards reduces measurement variability and aids in preventing erroneous reporting of growth and potentially unwarranted changes in management.

Main-duct Intraductal Papillary Mucinous Neoplasm: High Cancer Risk in Duct Diameter of 5 to 9 mm

OBJECTIVE

The 2012 international consensus guidelines for the management of intraductal papillary mucinous neoplasms (IPMN) recommend surgical treatment in main-duct IPMN patients with a main pancreatic duct (MPD) diameter of ≥10 mm. Aim of the present study was to analyze cancer risk in patients with an MPD diameter of less than 10 mm.

METHODS

All consecutive patients (prospective data protocol) with histological proof of IPMN who underwent surgery between January 2004 and December 2013 were included in the study. Clinical characteristics, particularly preoperative imaging with regard to morphology of the MPD, were correlated with final histopathology.

RESULTS

Among a total of 605 patients who underwent surgery for IPMN, there were 320 patients with MPD involvement, 238 patients with mixed-type IPMN, and 82 patients with main-duct IPMN alone. The total malignancy rate including high-grade dysplasia and invasive carcinoma in IPMNs with MPD involvement was 68%. When the MPD diameter was 5 to 9 mm, malignancy rate was 59%, whereas in MPD diameter more than 10 mm, it was 73%. No statistical correlations were observed between MPD diameter and clinical and/or IPMN features such as age, cyst location, mural nodules, serum tumor markers, or bilirubin.

CONCLUSIONS

Main-duct IPMNs with a MPD between 5 and 9 mm already bear a significant risk of malignancy. Therefore, surgical treatment is clearly indicated in patients with a MPD diameter of ≥5 mm and the 2012 guidelines should be discussed and adapted with regard to this topic.

Impact of next-generation sequencing on the clinical diagnosis of pancreatic cysts

BACKGROUND AND AIMS

The value of next-generation sequencing (NGS) of pancreatic cyst fluid relative to the clinical and imaging impression has not been well-studied. The aim of this study was to assess the impact of NGS on the clinical diagnosis from imaging and carcinoembryonic antigen (CEA) and thus the management of pancreatic cysts.

METHODS

Ninety-two pancreatic cyst fluids from 86 patients were analyzed by cytology, CEA, and targeted NGS. Cysts were classified by imaging as nonmucinous, mucinous, or not specified. NGS results were compared with the imaging impression stratified by CEA and cytology.

RESULTS

NGS impacted the clinical diagnosis by defining a cyst as mucinous in 48% of cysts without elevated CEA levels. The VHL gene in 2 intraductal papillary mucinous neoplasms (IPMNs) supported a serous cystadenoma. Twenty percent of cysts that were nonmucinous by imaging were mucinous by NGS. Of the 14 not-specific cysts, CEA levels were not elevated in 12 (86%), and NGS established a mucinous etiology in 3 (25%). A KRAS or GNAS mutation supported an IPMN with nonmucinous CEA in 71%. A KRAS mutation reclassified 19% of nonneoplastic cysts with nonmucinous CEA as mucinous. Seven cyst fluids (8%) had either a TP53 mutation or loss of CDKN2A or SMAD4 in addition to KRAS and/or GNAS mutations; 5 of 7 (71%) were clinically malignant, and high-grade cytology was detected in all 5. Overall, CEA was more specific for a mucinous etiology (100%), but NGS was more sensitive (86% vs 57%).

CONCLUSIONS

NGS of pancreatic cyst fluid impacts clinical diagnosis and patient management by defining, supporting, or changing the clinical diagnosis based on imaging and CEA. NGS was most valuable in identifying mucinous cysts with nonmucinous CEA. An added benefit is the potential to detect mutations late in the progression to malignancy that may increase the risk classification of the cyst based on imaging and cytology.

Pancreatic Solid and Cystic Neoplasms: Diagnostic Evaluation and Intervention

High-resolution imaging modalities, such as multi-detector computed tomography, MR imaging, and endoscopic ultrasound, are frequently used alone or in combination to characterize focal solid and cystic pancreatic neoplasms. Imaging in solid pancreatic neoplasms, typically adenocarcinoma and neuroendocrine tumors, is primarily used to detect and stage the extent of the tumor and to determine if complete surgical resection for cure is feasible. In cystic pancreatic masses, imaging aims to differentiate benign nonmucinous cystic lesions from potentially or frankly malignant mucin-producing cysts. Several noninvasive and invasive treatment options can be performed if surgical resection is not possible or contraindicated.

Clinical implication of serum carcinoembryonic antigen and carbohydrate antigen 19-9 for the prediction of malignancy in intraductal papillary mucinous neoplasm of pancreas

BACKGROUND

Little is known about the prognostic significance of serum carbohydrate antigen (CA) 19-9 and carcinoembryonic antigen (CEA) concentrations for predicting malignancy in patients with intraductal papillary mucinous neoplasm (IPMN) of pancreas.

METHOD

The study cohort consisted of 367 patients with surgical biopsy proven IPMN at Seoul National University Hospital. Preoperative serum tumor markers were evaluated and compared with other clinical variables.

RESULTS

Malignant pathology (high grade dysplasia [HGD] and invasive IPMN) was identified in 117 (31.9%) patients. Elevated serum CA19-9 was more frequent in patients with malignant (34.2%, P < 0.001; invasive IPMN vs. HGD 47.9% vs. 11.4%, P < 0.001) and main duct type (40.0%, P = 0.003) IPMN. Multivariate analysis showed main pancreatic duct (MPD) >5 mm (P < 0.001), mural nodules (P < 0.001), and elevated serum CA19-9 (P < 0.001) were independent predictors of malignancy. The sensitivity, specificity and accuracy were 34.2%, 92.4%, and 73.8%, respectively, for elevated serum CA19-9; 63.3%, 78.0%, and 73.3%, for MPD >5 mm; and 59.0%, 86.4%, and 77.7%, for mural nodules.

CONCLUSION

Serum CA19-9 is significantly higher in patients with malignant IPMN, especially in patients with invasive and main duct type IPMN. The diagnostic power of serum CA19-9 in predicting malignancy is comparable to that of MPD >5 mm and mural nodules.