Duodenal invasion by pancreatic adenocarcinoma: MDCT diagnosis of an aggressive imaging phenotype and its clinical implications

Efficacy Analysis of Suprapapillary versus Transpapillary Self-Expandable Metal Stents According to the Level of Obstruction in Malignant Extrahepatic Biliary Obstruction

Background/Aims

The use of a self-expandable metal stent (SEMS) is recommended for unresectable malignant biliary obstruction (MBO). Stent-related adverse events might differ according to the position of the stent through the ampulla of Vater (AOV). We retrospectively evaluated SEMS patency and adverse events according to the position of the SEMS.

Methods

In total, 280 patients who underwent endoscopic SEMS placement due to malignant distal biliary obstruction were analyzed retrospectively. Suprapapillary and transpapillary SEMS insertions were performed on 51 patients and 229 patients, respectively.

Results

Between the suprapapillary group (SPG) and transpapillary group (TPG), the stent patency period was not significantly different (median [95% confidence interval]: 107 days [82.3 to 131.7] vs 120 days [99.3 to 140.7], p=0.559). There was also no significant difference in the rate of adverse events. In subgroup analysis, the stent patency for an MBO located within 2 cm from the AOV was found to be significantly shorter than that for an MBO located more than 2 cm from the AOV in the SPG (64 days [0 to 160.4] vs 127 days [82.0 to 171.9], p<0.001) and TPG (87 days [52.5 to 121.5] vs 130 [97.0 to 162.9], p<0.001). Patients with an MBO located within 2 cm from the AOV in both groups had a higher percentage of duodenal invasion (SPG: 40.0% vs 4.9%, p=0.002; TPG: 28.6% vs 2.9%, p<0.001) than patients with an MBO located more than 2 cm from the AOV.

Conclusions

The SPG and TPG showed similar results in terms of stent patency and rate of adverse events. However, patients with an MBO located within 2 cm from the AOV had a higher percentage of duodenal invasion with shorter stent patency than those with an MBO located more than 2 cm from the AOV, regardless of stent position.

Perineural Invasion and Spread in Common Abdominopelvic Diseases: Imaging Diagnosis and Clinical Significance

Malignancies and other diseases may spread by multiple pathways, including direct extension, hematogenous spread, or via lymphatic vessels. A less-well-understood route is the peripheral nervous system, which is known as perineural spread (PNS). In addition to accounting for pain and other neurologic symptoms, PNS affects both disease prognosis and management. Although PNS is commonly discussed in relation to head and neck tumors, there is emerging data regarding PNS in abdominopelvic malignancies and other conditions such as endometriosis. Due to improved contrast and spatial resolution, perineural invasion, a finding heretofore diagnosed only at pathologic examination, can be detected at CT, MRI, and PET/CT. PNS most commonly manifests as abnormal soft-tissue attenuation extending along neural structures, and diagnosis of it is aided by optimizing imaging parameters, understanding pertinent anatomy, and becoming familiar with the typical neural pathways of spread that largely depend on the disease type and location. In the abdomen, the celiac plexus is a central structure that innervates the major abdominal organs and is the principal route of PNS in patients with pancreatic and biliary carcinomas. In the pelvis, the lumbosacral plexus and inferior hypogastric plexus are the central structures and principal routes of PNS in patients with pelvic malignancies. Although the imaging findings of PNS may be subtle, a radiologic diagnosis can have a substantial effect on patient care. Knowledge of anatomy and known routes of PNS and optimizing imaging parameters is of utmost importance in providing key information for prognosis and treatment planning. © RSNA, 2023 Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

Pancreatic Adenocarcinoma: Diagnostic Errors, Contributing Factors and Solutions

The purpose of this article is to review diagnostic errors in preoperative and post-operative imaging for pancreatic ductal adenocarcinoma (PDAC), discuss contributing factors, and provide solutions that minimize errors. Accurate radiological staging and restaging of PDAC dictates surgical management and errors can have significant negative effects on patient care, such as missed vessel involvement or metastatic disease that would preclude surgery. Familiarity with these errors and their contributing factors improves diagnostic accuracy and ultimately leads to improved patient outcomes.

MRI evaluation of pancreatic ductal adenocarcinoma: diagnosis, mimics, and staging

The radiologist's role in the evaluation of pancreatic ductal adenocarcinoma remains critical in the management of this deadly disease. Imaging plays a vital role in the diagnosis and staging of pancreatic cancer. Although CT is more commonly used for staging pancreatic cancer, MR is increasingly playing an important role in this regard. In our institution, all pancreatic malignancies undergo staging with MRI. In this pictoral essay, we illustrate the MR imaging features of pancreatic ductal adenocarcinoma and its mimics, and we also discuss pearls and pitfalls in MR staging of pancreatic carcinoma.