From the Guidelines
Endoscopic ultrasound (EUS) is a highly valuable diagnostic tool for evaluating pancreatic diseases, particularly for diagnosing and staging pancreatic adenocarcinoma, with a high diagnostic accuracy of up to 95% when combined with fine-needle aspiration (FNA) biopsy 1. The procedure involves inserting a thin, flexible tube with an ultrasound probe at its tip through the mouth or rectum to visualize structures such as the esophagus, stomach, pancreas, liver, and lymph nodes. EUS is particularly useful for:
- Diagnosing and staging gastrointestinal cancers
- Evaluating pancreatic diseases
- Assessing bile duct abnormalities
- Examining submucosal lesions The procedure also enables fine-needle aspiration (FNA) or biopsy of suspicious areas, allowing tissue sampling for definitive diagnosis. According to a recent study, EUS is the modality of choice to evaluate indeterminate subepithelial lesions of the GI tract and/or if non-diagnostic tissue by forceps biopsies 1. Patients typically receive sedation for comfort, and the procedure usually takes 30-90 minutes depending on complexity. Preparation involves fasting for 6-8 hours before the procedure, adjusting medications as directed by the physician, and arranging for transportation home afterward due to sedation effects. EUS is considered safe with minimal risks, though rare complications can include bleeding, infection, or perforation. Its high-resolution imaging capabilities make it superior to conventional imaging methods for certain conditions, particularly those involving deep tissue layers or small lesions in the digestive tract. Some key points to consider when using EUS for pancreatic adenocarcinoma include:
- EUS has limited value in detecting all metastatic lymph nodes, but is valuable in detecting vascular invasion and predicting resectability 1
- EUS can provide tissue samples via fine-needle aspiration, allowing for diagnostic accuracy of up to 95% when carried out by an experienced cytopathologist 1
- EUS can be used to evaluate the extent of tumor invasion, including the depth of tumor penetration and the presence of lymph node involvement 1
- EUS can be used in conjunction with other imaging modalities, such as CT and MRI, to provide a comprehensive evaluation of the patient's disease 1
From the Research
Diagnostic Capabilities of Endoscopic Ultrasound
- Endoscopic ultrasonography (EUS) has a higher diagnostic yield than positron emission tomography, computed tomography (CT), and transabdominal ultrasound for recognizing early pancreatic tumors 2.
- EUS has a sensitivity rate of 99% for lesions less than 2-3 cm in size, compared to 55% for CT 2.
- The accuracy for N staging with EUS is 64%-82% 2.
- EUS is currently the most sensitive imaging tool for the detection of solid pancreatic tumors 3.
Therapeutic Applications of Endoscopic Ultrasound
- EUS plays a therapeutic role in treating oncological pain through celiac plexus block, biliary drainage in obstructive jaundice, and aiding radiotherapy and chemotherapy 2.
- EUS-guided fiducial placement for local targeted radiotherapy treatment or EUS-guided radiofrequency ablation has been developed for local treatment, especially for patients with pancreatic cancer not suitable for surgical resection 3.
- EUS-guided therapeutic procedures, such as celiac plexus neurolysis for pain control and EUS-guided biliary drainage for biliary obstruction, have dramatically improved in recent years 3.
- EUS-guided fine needle injection of different types of drugs, implantation of fiducial markers, and the use of different thermal and nonthermal ablation devices and techniques have all been tested in preliminary human studies 4.
Comparison with Other Modalities
- EUS has been found to be superior to multidetector CT for T staging with less risk of overstaging 2.
- EUS is superior to MRCP and multiple detector CT in evaluating pancreatic divisum 5.
- Contrast-enhanced EUS is more valuable than EUS in autoimmune pancreatitis 5.
- EUS-guided pseudocyst drainage is safe with a high success rate 5.