Pancreatic Cystic Lesions: Next Generation of Radiologic Assessment.

Pancreatic cystic lesions are frequently identified on cross-sectional imaging. As many of these are presumed branch-duct intraductal papillary mucinous neoplasms, these lesions generate much anxiety for the patients and clinicians, often necessitating long-term follow-up imaging and even unnecessary surgical resections. However, the incidence of pancreatic cancer is overall low for patients with incidental pancreatic cystic lesions. Radiomics and deep learning are advanced tools of imaging analysis that have attracted much attention in addressing this unmet need, however, current publications on this topic show limited success and large-scale research is needed.

Comparison of Preoperative Imaging Modalities for the Assessment of Malignant Potential of Pancreatic Cystic Lesions: A Network Meta-analysis.

PURPOSE: The aims of this study are to compare the performance of various preoperative imaging modalities for assessing the malignant potential of pancreatic cystic lesions (PCLs) through a network meta-analysis (NMA) and to clarify the role of 18 F-FDG PET in the management of patients with PCL. METHODS: PubMed, EMBASE, and Cochrane Library were searched for the studies evaluating the performance of preoperative imaging modalities for identifying malignant PCLs. The NMA was performed for 4 representative categories of various imaging modalities in terms of diagnostic performance for differentiating malignant from benign PCL and intraductal papillary mucinous neoplasms only as a subgroup analysis. To calculate the probability of each imaging modality being the most effective diagnostic method, the surface under the cumulative ranking curve values were obtained. RESULTS: A total of 1018 patients from 17 direct comparison studies using 2 or more preoperative imaging modalities were included for differentiating malignant from benign PCL. The positive predictive value (PPV) and accuracy of 18 F-FDG PET were significantly higher than that of CT (PPV: odds ratio [OR], 2.66; 95% credible interval [CrI], 1.21-6.17; accuracy: OR, 2.63; 95% CrI, 1.41-5.38) or MRI (PPV: OR, 2.50; 95% CrI, 1.09-6.26; accuracy: OR, 2.50; 95% CrI, 1.28-5.47) in all PCLs, as well as in the subgroup analysis for intraductal papillary mucinous neoplasm only. 18 F-FDG PET showed the highest surface under the cumulative ranking curve values in all diagnostic performance areas of sensitivity, specificity, PPV, negative predictive value, and accuracy, followed by MRI or CT. CONCLUSIONS: The results from this NMA suggest that 18 F-FDG PET is the best preoperative imaging modality for differentiating malignant from benign PCLs and that it can be used for the preoperative evaluation of PCLs.

Pancreatic Cystic Lesions and Malignancy: Assessment, Guidelines, and the Field Defect.

The widespread use of high-spatial-resolution cross-sectional imaging has led to an increase in detection of incidental pancreatic cystic lesions. These lesions are a diverse group, ranging from indolent and premalignant lesions to invasive cancers. The diagnosis of several of these lesions can be suggested on the basis of their imaging appearance, while many other lesions require follow-up imaging and/or aspiration. The smaller cystic lesions, often branch-duct intraductal papillary mucinous neoplasms, have overlapping imaging characteristics that make diagnostic assessment of the natural history and malignancy risk confusing. Expert panels have developed societal guidelines, based on a consensus, for surveillance of these lesions. However, these guidelines are often inconsistent and are constantly evolving as additional scientific data are accumulated. Identification of features associated with increased risk of malignancy is important for proper management. The concept of field defect, whereby pancreatic adenocarcinoma develops at a site different from the site of the pancreatic cyst, adds to the complexity of screening guidelines. As a result of the differences in guidelines, key stakeholders (eg, radiologists, gastroenterologists, and surgeons) must review and come to a consensus regarding which guideline, or combination of guidelines, to follow at their individual institutions. Standardized reporting and macros are helpful for ensuring the uniformity of interpretations. Radiologists play a critical role in the detection and characterization of pancreatic cystic lesions, in the follow-up recommendations for these lesions, and in the detection of associated cancer. An invited commentary by Zaheer is available online. Online supplemental material is available for this article. ©RSNA, 2021.

Cost-effectiveness of consensus guideline based management of pancreatic cysts: The sensitivity and specificity required for guidelines to be cost-effective.

BACKGROUND: Detection of cystic lesions of the pancreas has outpaced our ability to stratify low-grade cystic lesions from those at greater risk for pancreatic cancer, raising a concern for overtreatment. METHODS: We developed a Markov decision model to determine the cost-effectiveness of guideline-based management for asymptomatic pancreatic cysts. Incremental costs per quality-adjusted life year gained and survival were calculated for current management guidelines. A sensitivity analysis estimated the effect on cost-effectiveness and mortality if overtreatment of low-grade cysts is avoided, and the sensitivity and specificity thresholds required of methods of cyst stratification to improve costs expended. RESULTS: "Surveillance" using current management guidelines had an incremental cost-effectiveness ratio of $171,143/quality adjusted life year compared with no surveillance or operative treatment ("do nothing"). An incremental cost-effectiveness ratio for surveillance decreases to $80,707/quality adjusted life year if the operative overtreatment of low-grade cysts was avoided. Assuming a societal willingness-to-pay of $100,000/quality adjusted life year, the diagnostic specificity for high-risk cysts must be >67% for surveillance to be preferred over surgery and "do nothing." Changes in sensitivity alone cannot make surveillance cost-effective. Most importantly, survival in surveillance is worse than "do nothing" for 3 years after cyst diagnosis, although long-term survival is improved. The disadvantage is eliminated when overtreatment of low-grade cysts is avoided. CONCLUSION: Current management of pancreatic cystic lesions is not cost-effective and may increase mortality owing to overtreatment of low-grade cysts. The specificity for risk stratification for high-risk cysts must be greater than 67% to make surveillance cost-effective.

Downstream Costs Associated With Incidental Pancreatic Cysts Detected at MRI.

OBJECTIVE: The purpose of this study is to assess downstream costs associated with pancreatic cysts incidentally detected at MRI. MATERIALS AND METHODS: Two hundred patients with an incidental pancreatic cyst detected at MRI were identified. Downstream events (imaging, office visits, endoscopic ultrasound-guided fine-needle aspiration, or chemotherapy) were identified from the electronic medical record. Radiologists' recommendations and ordering physician management were classified relative to the American College of Radiology (ACR) incidental findings committee recommendations. Costs for the downstream events were estimated using national Medicare rates and a 3% annual discount rate. Mean costs were computed. RESULTS: Estimated downstream costs averaged $460 per cyst ($872 per cyst with any follow-up testing). Nine patients had a clinically relevant outcome during follow-up (increase in cyst size, development of new cyst, or development of pancreatic cancer). Downstream cost per cyst with a clinically relevant outcome was $1364. Costs were greater when ordering physicians overmanaged ($842) versus when they were adherent ($631) or undermanaged ($252) relative to radiologist recommendation. Although costs were $252 when ordering physicians undermanaged relative to ACR incidental findings committee recommendations, costs were similar when ordering physicians were adherent ($811) or overmanaged ($845) relative to ACR incidental findings committee recommendations. Costs did not vary significantly according to whether radiologists recommended follow-up testing ($317-$491) or whether radiologist recommendations were adherent, undermanaged, or overmanaged relative to ACR incidental findings committee recommendations ($344-$528). CONCLUSION: The findings suggest a role for targeted educational efforts, collaborative partnerships, and other initiatives to foster greater adherence to radiologist recommendations, including critical test results notification systems, automated reminders within electronic health systems, and stronger language within radiology reports when no follow-up testing is recommended.

Comparison of endoscopic ultrasound, computed tomography and magnetic resonance imaging in assessment of detailed structures of pancreatic cystic neoplasms.

AIM: To evaluate the advantages of endoscopic ultrasound (EUS) in the assessment of detailed structures of pancreatic cystic neoplasms (PCNs) compared to computed tomography (CT) and magnetic resonance imaging (MRI). METHODS: All patients with indeterminate PCNs underwent CT, MRI, and EUS. The detailed information, including size, number, the presence of a papilla/nodule, the presence of a septum, and the morphology of the pancreatic duct of PCNs were compared among the three imaging modalities. The size of each PCN was determined using the largest diameter measured. A cyst consisting of several small cysts was referred to as a mother-daughter cyst. Disagreement among the three imaging modalities regarding the total number of mother cysts resulted in the assumption that the correct number was the one in which the majority of imaging modalities indicated. RESULTS: A total of 52 females and 16 males were evaluated. The median size of the cysts was 42.5 mm by EUS, 42.0 mm by CT and 38.0 mm by MRI; there was no significant difference in size as assessed among the three imaging techniques. The diagnostic sensitivity and ability of EUS to classify PCNs were 98.5% (67/68) and 92.6% (63/68), respectively. These percentages were higher than those of CT (73.1%, P < 0.001; 17.1%, P < 0.001) and MRI (81.3%, P = 0.001; 20.3%, P < 0.001). EUS was also able to better assess the number of daughter cysts in mother cysts than CT (P = 0.003); however, there was no significant difference between EUS and MRI in assessing mother-daughter cysts (P = 0.254). The papilla/nodule detection rate by EUS was 35.3% (24/68), much higher than those by CT (5.8%, 3/52) and MRI (6.3%, 4/64). The detection rate of the septum by EUS was 60.3% (41/68), which was higher than those by CT (34.6%, 18/52) and by MRI (46.9%, 30/64); the difference between EUS and CT was significant (P = 0.02). The rate of visualizing the pancreatic duct using EUS was 100%, whereas using CT and MRI it was less than 10%. CONCLUSION: EUS helps visualize the detailed structures of PCNs and has many advantages over CT and MRI. EUS is valuable in the diagnosis and assessment of PCNs.

Assessment of morbidity and mortality associated with endoscopic ultrasound-guided fine-needle aspiration for pancreatic cystic lesions: A systematic review and meta-analysis.

BACKGROUND AND AIM: With increased availability of imaging technology, detection of pancreatic cystic lesions (PCL) is on the rise. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) improves the diagnosis accuracy of PCL. Systematic evaluation of morbidity and mortality associated with EUS-FNA for PCL has not been carried out. We conducted a systematic review and meta-analysis of morbidity and mortality associated with EUS-FNA. METHODS: A literature search for relevant English-language articles was conducted on PubMed and EMBASE databases. Main outcome measures for this analysis were adverse effects of diagnostic EUS-FNA, and the associated morbidity and mortality, in patients with PCL. RESULTS: Forty studies, with a combined subject population of 5124 patients with PCL, satisfied the inclusion criteria. Overall morbidity as a result of adverse events of EUS-FNA was 2.66% (95% confidence interval [CI]: 1.84-3.62%), and the associated mortality was 0.19% (95% CI: 0.09-0.32%). Common post-procedure adverse events included pancreatitis 0.92% (95% CI: 0.63-1.28%), hemorrhage 0.69% (95% CI: 0.42-1.02%), pain 0.49% (95% CI: 0.27-0.79%), infection 0.44% (95% CI: 0.27-0.66%), desaturation 0.23% (95% CI: 0.12-0.38%) and perforation 0.21% (95% CI: 0.11-0.36%). There was no peritoneal seeding in our study. Incidence of adverse events associated with prophylactic periprocedural antibiotic use was 2.77% (95% CI: 1.87-3.85%). CONCLUSIONS: EUS-FNA is a safe procedure for diagnosis of PCL and is associated with a relatively low incidence of adverse events. Most adverse events were mild, self-limiting, and did not require medical intervention.

Needle-based confocal laser endomicroscopy in pancreatic cystic tumors assessment.

Pancreatic cystic tumors (PCT) are relatively common findings in general population due to the widespread use of cross-sectional imaging. PCT can be benign, with premalignant potential or malignant, a different management being applied for each type: benign cysts are usually referred for follow-up (based on imaging), while premalignant or malignant lesions should be surgically resected. The aim of this review is to describe the latest imaging technique that could be used for PCT diagnosis and to establish its clinical impact. Endoscopic ultrasound (EUS) is generally used to evaluate a pancreatic mass and to identify its characteristics. It offers a good visualization of the lesion. When combined with fine needle aspiration and cystic fluid analysis, the diagnosis potential is increased, although its accuracy for differentiating benign and malign tumors remains modest. EUS-guided needle-based confocal laser endomicroscopy (nCLE) is a new imaging technique that uses a miniprobe thin enough to be passed through a 19G needle. It provides in vivo images of the pancreas at a cellular level, offering the possibility to assess any changes that might have occurred. Several studies have shown that nCLE is feasible to use for PCT evaluation, imaging criteria being established with 100% specificity for intraductal papillary mucinous neoplasms (IPMN) and serous cystadenoma (SCA). Regarding the safety, more studies are needed. EUS-guided nCLE appears to be a new imaging technique that provides encouraging results for differential diagnosis between mucinous/non-mucinous cysts.

Comparison of endoscopic ultrasound and computed tomography in the assessment of pancreatic cyst size using pathology as the gold standard.

BACKGROUND/OBJECTIVES: Accurate assessment of whether a cyst is greater than 3 cm is an essential component when considering resection especially for mucinous lesions. The most accurate method of assessing cyst size is uncertain with many patients undergoing several complimentary imaging modalities. This study aimed to compare the accuracy of endoscopic ultrasound (EUS) with CT scanning in assessing pancreatic cyst size compared to histology. METHODS: Patients referred for EUS of a pancreatic cystic lesion from April 2003 to August 2011. Patient age and gender, lesion size and site were recorded and compared using cyst size at histology compared to EUS and CT recorded within 3 months of surgery. Subgroup analysis was performed with respect to cyst site and proven mucinous lesions. RESULTS: 357 patients were included of which 70 (mean age 60.6 years, 24 males) had undergone surgical resection. The resected cysts were located 30/17/23 in the head/body/tail of the pancreas. Median size at histology was 32 mm compared to 35 mm at EUS (p = 0.47) and 35 mm at CT (p = 0.52). For mucinous lesions alone, median size at histology was 32 mm compared to 33 mm at EUS (p = 0.46) and 35 mm at CT (p = 0.39). EUS and CT had comparable sensitivity, specificity, negative predictive value, positive predictive value and accuracy for all cyst types and locations. CONCLUSIONS: CT and EUS measurements are not significantly different to pathological size following resection of pancreatic cystic lesions. CT and EUS are interchangeable investigations for determining cyst size pre-operatively although EUS has the additional advantage of fluid sampling.

A clinical algorithm for the assessment of pancreatic lesions: utilization of 16- and 64-section multidetector CT and endoscopic ultrasound.

Pancreatic masses may be solid or cystic, benign or malignant, and their characterization can often be difficult as there is considerable overlap in their imaging features. Multidetector computed tomography (MDCT) with multiplanar reconstructions offers improved resolution and optimum visualization of the peripancreatic vasculature, which has improved the accuracy in predicting surgical resectability. Endoscopic ultrasound (EUS) is valuable in the detection of tumours not identified on CT. It is also accurate in identifying vascular involvement, which complements MDCT in predicting resectability. In cases of diagnostic uncertainty, EUS-guided fine-needle aspiration (FNA) can be used to obtain tissue samples from solid lesions and fluid aspirates from cystic lesions, allowing histological, cytological, and biochemical analysis to determine the nature of the lesion. This article focuses on the MDCT and EUS appearances of common pancreatic malignancies, highlighting their relative advantages and their complementary role in detecting and characterizing pancreatic masses. A clinical algorithm for the assessment of pancreatic malignancy, as practised in our institution, is outlined.

Preoperative evaluation of pancreatic cystic lesions: cost-benefit analysis and proposed management algorithm.

BACKGROUND: This study was performed to develop a management algorithm that accurately predicts the necessity of operative intervention and results in significant cost savings for patients with cystic pancreatic tumors. METHODS: We reviewed 60 patients treated between 1992 and 2003. Accuracy rates of tests used to differentiate benign from premalignant and malignant cysts were calculated. A management algorithm was generated that incorporated clinical presentation, radiologic findings, and selective use of endoscopic procedures. This algorithm was tested for predictive accuracy, and savings between actual management and proposed management were compared. RESULTS: There was an average of 3 preoperative tests performed per patient. Endoscopic procedures included endoscopic retrograde cholangiopancreatography in 21 patients and endoscopic ultrasound in 25 patients. A cyst fluid carcinoembryonic antigen (CEA) level of 158 ng/mL or greater had an accuracy rate of 87.5% that was significantly higher than endoscopic retrograde cholangiopancreatography (72%), endoscopic ultrasound morphology (45%), or endoscopic ultrasound cytology (66.7%). There was no combination of tests that provided greater accuracy than cyst fluid CEA level alone (P < .05). The management algorithm had a positive predictive value of 81%. The average actual cost of radiographic and endoscopic procedures was dollar 8,080 per patient. The proposed cost based on the algorithm was dollar 6,677 with a savings of dollar 1,403 per patient (P = .009). CONCLUSIONS: In patients with clinical symptoms or radiographic findings of mucinous or malignant tumors, further testing is excessive. Of endoscopic tests available, the cystic fluid CEA level most accurately predicts the presence of a mucinous neoplasm. A management algorithm based on presenting symptoms, radiographic findings, and cyst fluid CEA level provides a guideline for the evaluation of cystic lesions in the most cost-efficient manner while ensuring proper care.

Angiographic assessment of pancreatic pseudocyst: a reappraisal.

The correct diagnosis was established by angiography in 16 of 21 patients with pancreatic pseudocyst. The characteristic angiographic abnormalities are arcuate stretching of intrapancreatic arteries combined with a filling defect in the parenchymal phase of the angiogram. In the five false negative patients, the diagnosis was not made either because of the small size of the pseudocyst or a primary extrapancreatic location of the lesion. Because of this high false negative rate and the accuracy of B-mode ultrasonic scanning in abdominal cystic lesions, ultrasound should be the primary diagnostic modality in patients with suspected pancreatic pseudocysts.