Accuracy of 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for Detection of Recurrent or Metastatic Colorectal Carcinoma in Patients with Rising Carcinoembryonic Antigen Levels

Abstract

Objective: A rise in carcinoembryonic antigen level is commonly encountered during follow-up of patients with colorectal carcinoma. This study aimed to evaluate the diagnostic performance of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (18 F-FDG PET/CT) studies for detection of recurrent or metastatic colorectal carcinoma in patients with rising carcinoembryonic antigen levels. Methods: Patients with colorectal carcinoma in clinical remission with rising carcinoembryonic antigen levels who underwent PET/CT in Prince of Wales Hospital, Hong Kong from 2008 to 2011 were included. Patient demographics, carcinoembryonic antigen levels, and clinical follow-up data were recorded. Outcomes were determined by histopathological findings or at least 12-month follow-up. Results: Forty-two PET/CT studies of 37 patients (16 men and 21 women; mean [standard deviation] age, 65.8 [11.6] years) were included. Carcinoembryonic antigen levels ranged from 1.8 to 45 µg/l (9 patients had normal carcinoembryonic antigen levels of <5 µg/l, but serial carcinoembryonic antigen measurements showed a rising trend). Among the 42 events, 23 (55%) had a positive final diagnosis. The sensitivity, specificity, and positive and negative predictive values of PET/CT for recurrence or metastases were 91.3%, 89.5%, 91.3%, and 89.5%. Conclusion: 18 F-FDG PET/CT is a useful imaging modality to evaluate recurrence or metastases in patients with colorectal carcinoma in clinical remission but showing rising carcinoembryonic antigen levels.

Prospective evaluation of plasma Epstein–Barr virus DNA clearance and fluorodeoxyglucose positron emission scan in assessing early response to chemotherapy in patients with advanced or recurrent nasopharyngeal carcinoma

“…The dual PET-CT (plain) were performed with the Philips GEMINI GXL PET-CT Imaging System (Phillips Medical Systems, The Netherlands) as previously described. 12 The contrast-enhanced CT scan was performed on a helical CT scanner (VCT, General Electric Medical Systems, Milwaukee, WI). The PET images (with and without attenuation correction), CT images, and the dual PET-CT fusion images were interpreted in parallel.…”

“…The PET images (with and without attenuation correction), CT images, and the dual PET-CT fusion images were interpreted in parallel. 12 Visual and semi-quantitative assessment of the regions of interest (ROIs) was made by measuring the maximum standardised uptake value (SUVmax) normalised to injected activity and the patient’s body weight. ROIs with a SUVmax value of > 2.5 were regarded as pathological and a maximum of 10 target lesions were selected per patient per scan, with a maximum of 5 lesions per organ.…”