FDG-PET/CT As noted earlier, there is considerable variability in how the CT portion of the examination is obtained for FDG- PET/CT with regard to whether IV or oral contrast is administered. When performed without IV contrast, it does not have a role in the assessment for potential vascular involvement. When performed with IV contrast enhancement, it is typically acquired as a single phase of contrast enhancement at variable slice thickness and variable reconstructed display field-of-view between institutions. These parameters would affect the usefulness and effectiveness of local staging. FDG-PET/CT, when used in the setting of preoperative staging, is therefore typically used as a whole-body examination for follow-up to contrast-enhanced CT or MRI, which themselves would already provide information regarding liver metastases, potential peritoneal implants, and possible adenopathy. This is likely why most of the studies retrieved in our literature search evaluated the usefulness of FDG-PET/CT as a follow-up study whole body examination to conventional cross-sectional imaging for the detection of unexpected distant metastases. One of the challenges encountered in evaluating the studies, is that often distant metastases (liver, peritoneal, lung, bone, nodes) were put together into a single group rather than subgroups by the type of distant metastasis. The results are variable across studies with the detection rate of unexpected distant metastases generally identified in patients as probably resectable based on contrast-enhanced CT or MRI, ranging from 2.5% to 41% [43-48]. A recent meta-analysis of FDG-PET/CT imaging (4 studies, 101 patients) showed a pooled sensitivity of 64% and specificity of 81% for metastatic nodal disease, and a sensitivity of 67% and specificity of 96% for liver metastases [49]. Staging of Pancreatic Ductal Adenocarcinoma Variant 2: Pancreatic ductal adenocarcinoma. Follow-up post-neoadjuvant therapy.
Staging of Pancreatic Ductal Adenocarcinoma. FDG-PET/CT As noted earlier, there is considerable variability in how the CT portion of the examination is obtained for FDG- PET/CT with regard to whether IV or oral contrast is administered. When performed without IV contrast, it does not have a role in the assessment for potential vascular involvement. When performed with IV contrast enhancement, it is typically acquired as a single phase of contrast enhancement at variable slice thickness and variable reconstructed display field-of-view between institutions. These parameters would affect the usefulness and effectiveness of local staging. FDG-PET/CT, when used in the setting of preoperative staging, is therefore typically used as a whole-body examination for follow-up to contrast-enhanced CT or MRI, which themselves would already provide information regarding liver metastases, potential peritoneal implants, and possible adenopathy. This is likely why most of the studies retrieved in our literature search evaluated the usefulness of FDG-PET/CT as a follow-up study whole body examination to conventional cross-sectional imaging for the detection of unexpected distant metastases. One of the challenges encountered in evaluating the studies, is that often distant metastases (liver, peritoneal, lung, bone, nodes) were put together into a single group rather than subgroups by the type of distant metastasis. The results are variable across studies with the detection rate of unexpected distant metastases generally identified in patients as probably resectable based on contrast-enhanced CT or MRI, ranging from 2.5% to 41% [43-48]. A recent meta-analysis of FDG-PET/CT imaging (4 studies, 101 patients) showed a pooled sensitivity of 64% and specificity of 81% for metastatic nodal disease, and a sensitivity of 67% and specificity of 96% for liver metastases [49]. Staging of Pancreatic Ductal Adenocarcinoma Variant 2: Pancreatic ductal adenocarcinoma. Follow-up post-neoadjuvant therapy.