Detection of histologically proven peritoneal carcinomatosis with fused 18F-FDG-PET/MDCT.

OBJECTIVE: To evaluate peritoneal carcinomatosis in patients with gastrointestinal and gynecologic malignancies and to assess the diagnostic role for 18-FDG-PET and MDCT alone in comparison to the diagnostic accuracy of fused 18F-FDG-PET/MDCT by using surgical and histopathological findings as the standard of reference.

METHODS AND SUBJECTS: Sixty-two patients (13 males, 49 females; age range 43-81; mean age, 62 years with suspected peritoneal carcinomatosis were reviewed for the presence of peritoneal lesions on 18F-FDG-PET/MDCT scans (Discovery LS, GE Medical Systems). The results were compared with the histological findings at laparatomy. Thirty-one patients had peritoneal metastases, while 31 patients had negative histological findings at laparotomy.

RESULTS: CT detected peritoneal seeding in 26/31 patients, 18F-FDG-PET in 25/31 patients, and 18F-FDG-PET/MDCT in 30/31 patients, for a sensitivity of 88%, 88%, and 100%, respectively. False-positive findings were seen in MDCT in one patient, in 18F-FDG-PET in two patients, and in 18F-MDCT-PET/MDCT in one patient, for a specificity of 97%, 94%, and 97%, respectively.

CONCLUSION: Fused 18F-FDG-PET/MDCT is superior to MDCT and 18F-FDG-PET alone for the detection of peritoneal carcinomatosis especially in small lesions and it offers exact anatomic information for surgical treatment.