EUS EUS A recent meta-analysis of 29 studies that incorporated EUS showed EUS to have a pooled sensitivity of 85% and specificity of 91% for vascular invasion [41]. Notably, the same study noted that the criteria for identifying arterial invasion have not been standardized, which is a constraining factor when attempting to compare between modalities and likely accounts for the wide range of sensitivity for vascular invasion of EUS in this meta-analysis (62% to 100%). The authors noted in their review that there are little comparative data between arterial and venous assessments, and that overall it appeared that CT and EUS performed comparably for assessing venous involvement and that CT may be superior for the assessment of invasion of arterial structures [41]. With regard to nodal disease, EUS has the advantage in that it can be combined with FNA to greatly improve its specificity. A recent meta-analysis of 8 studies showed a pooled sensitivity of 58% and specificity of 85% for detecting nodal metastases with EUS alone [41]. Although the meta-analysis did not include an assessment of multiple studies with EUS that included FNA, the authors did note that EUS would likely improve nodal staging, and cited a study that reported a sensitivity of 82% and specificity of 100% to confirm malignant adenopathy [42]. Because of its narrow field-of-view, and the limited region of anatomic coverage, EUS does not have a role for assessment of peritoneal disease. EUS allows for a limited examination of the left liver lobe and possible FNA of these lesions. No studies have directly compared the accuracy of EUS and cross-sectional imaging for left-sided liver metastasis. Imaging of the right liver is difficult and unreliable by EUS. US Difficulties in visualizing the pancreas in detail because of either body habitus or commonly interposed bowel gas limit the usefulness of transabdominal US for staging.
Staging of Pancreatic Ductal Adenocarcinoma. EUS EUS A recent meta-analysis of 29 studies that incorporated EUS showed EUS to have a pooled sensitivity of 85% and specificity of 91% for vascular invasion [41]. Notably, the same study noted that the criteria for identifying arterial invasion have not been standardized, which is a constraining factor when attempting to compare between modalities and likely accounts for the wide range of sensitivity for vascular invasion of EUS in this meta-analysis (62% to 100%). The authors noted in their review that there are little comparative data between arterial and venous assessments, and that overall it appeared that CT and EUS performed comparably for assessing venous involvement and that CT may be superior for the assessment of invasion of arterial structures [41]. With regard to nodal disease, EUS has the advantage in that it can be combined with FNA to greatly improve its specificity. A recent meta-analysis of 8 studies showed a pooled sensitivity of 58% and specificity of 85% for detecting nodal metastases with EUS alone [41]. Although the meta-analysis did not include an assessment of multiple studies with EUS that included FNA, the authors did note that EUS would likely improve nodal staging, and cited a study that reported a sensitivity of 82% and specificity of 100% to confirm malignant adenopathy [42]. Because of its narrow field-of-view, and the limited region of anatomic coverage, EUS does not have a role for assessment of peritoneal disease. EUS allows for a limited examination of the left liver lobe and possible FNA of these lesions. No studies have directly compared the accuracy of EUS and cross-sectional imaging for left-sided liver metastasis. Imaging of the right liver is difficult and unreliable by EUS. US Difficulties in visualizing the pancreas in detail because of either body habitus or commonly interposed bowel gas limit the usefulness of transabdominal US for staging.