imaging of peritoneal carcinomatosis with FDG PET-CT: diagnostic patterns, case examples and pitfalls

Early diagnosis of peritoneal spread in malignant disease\r\nis essential to prevent unnecessary laparotomies and to\r\nselect the patients in whom complete cytoreduction is\r\nfeasible. Although anatomic imaging is the mainstay for\r\nevaluating peritoneal seeding, small neoplastic implants\r\ncan be difficult to detect with CT andMR imaging. FDG\r\nPET-CT has the potential to improve detection of peritoneal\r\nmetastases as lesion conspicuity is high at PET\r\ndue to low background activity and fused PET-CT offers\r\nthe combined benefits of anatomic and functional\r\nimaging. Correlation of uptake modalities with the\r\npathogenesis of intraperitoneal spread of malignancies,\r\nprovides a rational system of analysis and is essential to\r\ndefine disease. Distinct patterns appear to predict the\r\npresence of either nodular or diffuse peritoneal pathology.\r\nMain pitfalls are related to normal physiologic\r\nactivity in bowel loops and blood vessels or focal retained\r\nactivity in ureters and urinary bladder. PET-CT is\r\nmost suitable in patients with high tumor markers and\r\nnegative or uncertain conventional imaging data and in\r\nselecting patients for complete cytoreduction. FDG PETCT\r\nadds to conventional imaging in the detection and\r\nstaging of peritoneal carcinomatosis and is a useful\r\ndiagnostic tool in monitoring response to therapy and in\r\nlong term follow-up.