Endoscopic ultrasonography for the evaluation of pancreatic cystic neoplasms

Contrast-enhanced guided endoscopic ultrasound procedures

Contrast-enhanced endoscopic ultrasound (CH-EUS) can overcome the limitations of endoscopic ultrasound-guided acquisition by identifying microvessels inside inhomogeneous tumours and improving the characterization of these tumours. Despite the initial enthusiasm that oriented needle sampling under CH-EUS guidance could provide better diagnostic yield in pancreatic solid lesions, further studies did not confirm the supplementary values in cases of tissue acquisition guided by CH-EUS. This review details the knowledge based on the available data on contrast-guided procedures. The indications for CH-EUS tissue acquisition include isoechoic EUS lesions with poor visible delineation where CH-EUS can differentiate the lesion vascularisation from the surrounding parenchyma and also the mural nodules within biliopancreatic cystic lesions, which occur in select cases. Additionally, the roles of CH-EUS-guided therapy in patients whose pancreatic fluid collections or bile ducts that have an echogenic content have indications for drainage, and patients who have nonvisualized vessels that need to be highlighted via Doppler EUS are presented. Another indication is represented if there is a need for an immediate assessment of the post-radiofrequency ablation of pancreatic neuroendocrine tumours, in which case CH-EUS can be used to reveal the incomplete tumour destruction.

Use of contrast-enhanced harmonic endoscopic ultrasonography for the diagnosis of pancreatic cystic lesions

Endoscopic ultrasonography (EUS) provides high spatial and contrast resolution and is a useful tool for evaluating the pancreato-biliary regions. Recently, contrast-enhanced harmonic EUS (CH-EUS) has been used to evaluate lesion vascularity, especially for the diagnosis of pancreatic tumors. CH-EUS adds two major advantages when diagnosing pancreatic cystic lesions (PCL). First, it can differentiate between mural nodules and mucous clots, thereby improving the accurate classification of PCL. Second, it helps with evaluation of the malignant potential of PCL, especially of intraductal papillary mucinous neoplasms by revealing the vascularity in the mural nodules and solid components. This review discusses the use and limitations of CH-EUS for the diagnosis of PCL.

Factors associated with misdiagnosis of preoperative endoscopic ultrasound in patients with pancreatic cystic neoplasms undergoing surgical resection

PURPOSE

Pancreatic cystic lesions (PCLs) include various types of cysts. Accurate preoperative diagnosis is essential to avoid unnecessary surgery on benign cysts. In this study, we aimed to identify the factors associated with misdiagnosis in preoperative endoscopic ultrasound (EUS) imaging and clinicopathological findings for PCLs.

METHODS

This study included 302 surgically resected patients with PCLs who underwent preoperative EUS. The preoperative EUS findings were re-evaluated and compared with the pathological diagnosis. Additionally, the factors associated with misdiagnosis of PCLs were investigated by multivariate analysis.

RESULTS

The preoperative diagnoses of PCLs were intraductal papillary mucinous neoplasm (IPMN) in 213 patients (70.5%), mucinous cystic neoplasm (MCN) in 33 patients (10.9%), serous neoplasm (SN) in 7 patients (2.3%), cystic degeneration cyst of solid tumor in 46 patients (15.2%), and pancreatic cancer with cystic degeneration in three patients (1.0%). A discrepancy between preoperative and postoperative diagnosis was found in 47 patients (15.6%). Based on the pathological diagnosis, the sensitivity of preoperative EUS imaging was IPMN 97.6% (206/211), MCN 90.0% (18/19), cystic degeneration 87.1% (27/31), and SN 15.4% (2/13). Multivariate analysis revealed that main pancreatic duct (MPD) communication ( - ) (odds ratio (OR), 4.54; 95% confidence interval (CI) 1.29-15.9), honeycomb-like structure ( +) (OR, 14.7; 95% CI 2.61-83.3), and MPD size ≦ 2 mm (OR, 16.3; 95% CI 3.93-67.6) were independently associated with misdiagnosis.

CONCLUSION

For cases in which MCN and cystic degeneration of solid tumor are presumed based on preoperative EUS imaging and cases with PCLs with a honeycomb-like structure, diagnosis with multimodalities or fluid analysis with EUS-guided fine-needle aspiration should be considered.

Transabdominal ultrasonographic diagnosis of relatively rare pancreatic neoplasms

There are various types of pancreatic neoplasms, and their prognosis and treatment methods are different. Therefore, accurate diagnosis is important to determine the best treatment strategy. Transabdominal ultrasonography is frequently used as a screening examination for diagnostic imaging of pancreatic neoplasms. In this review, we have focused on the characteristics of ultrasonic findings for relatively rare pancreatic neoplasms.

Diagnostic Yield of Transabdominal Ultrasonography for Evaluation of Pancreatic Cystic Lesions Compared with Endoscopic Ultrasonography

Detection rates of pancreatic cystic lesions (PCLs) have increased, resulting in greater requirements for regular monitoring using imaging modalities. We aimed to evaluate the capability of ultrasonography (US) for morphological characterization of PCLs as a reference standard using endoscopic ultrasonography (EUS). A retrospective analysis was conducted of 102 PCLs from 92 patients who underwent US immediately prior to EUS between January 2014 and May 2017. The intermodality reliability and agreement of the PCL morphologic findings of the two techniques were analyzed and compared using the intraclass correlation coefficient and κ values. The success rates of US for delineating PCLs in the head, body, and tail of the pancreas were 77.8%, 91.8%, and 70.6%, respectively. The intraclass correlation coefficient for US and the corresponding EUS lesion size showed very good reliability (0.978; p < 0.001). The κ value between modalities was 0.882 for pancreatic duct dilation, indicating good agreement. The κ values for solid components and cystic wall and septal thickening were 0.481 and 0.395, respectively, indicating moderate agreement. US may be useful for monitoring PCL growth and changes in pancreatic duct dilation, but it has limited use in the diagnosis and surveillance of mural nodules or cystic wall thickness changes.