5505. The Role of Staging CT versus MRI in Evaluating Liver Metastases from Pancreatic Ductal Adenocarcinoma (PDA)
Authors * Denotes Presenting Author
  1. Hala Khasawneh *; Memorial Sloan Kettering Cancer Center; UT Southwestern Medical Center
  2. Tae-Hyung Kim; Memorial Sloan Kettering Cancer Center
  3. Wyanne Law; Memorial Sloan Kettering Cancer Center
  4. Lee Rodriguez; Memorial Sloan Kettering Cancer Center
  5. Maria El Homsi; Memorial Sloan Kettering Cancer Center
To compare the performance of CT versus MRI for detection of liver metastasis in patients with borderline resectable or locally advanced pancreatic ductal adenocarcinoma (PDA).

Materials and Methods:
This retrospective pilot study included 49 treatment-naïve patients with biopsy-proven PDA (mean age: 68 years; range: 24 - 88 years; 29 women) who underwent CT and MRI within a 2-week period. Imaging was reviewed by two radiologists independently. Reference standard was histopathology or clinicoradiologic follow-up.

A total of 24 (49%) patients had liver metastases, which were proven on histopathology (<em>n</em> = 6) or follow-up (<em>n</em> = 18). CT patient-level performance for liver metastases vis-à-vis MRI (similar sensitivity of 97.9%, specificity 61.5% vs. 62.5%, PPV 69.7% vs.72.4%, similar negative predictive value (NPV) of 97.1%, and accuracy 78.8% vs. 80.3%). There interreader agreement was perfect when interpreting CT compared to good agreement in MRI (Kappa value of 1.00 vs. 0.66).

CT is a widely available imaging tool which has comparable performance to MRI in characterizing hypodense liver lesion in the patients with PDA with perfect interreader agreement. Therefore, it can serve as a readily available and more cost-effective substitute for MRI in staging PDA for detection of liver metastases. We aim to further validate these results by increasing the number of patients and investigating the implications of underlying genetic mutations.