Recurrence of colorectal tumors: PET evaluation

Radiology. 1989 Feb;170(2):329-32. doi: 10.1148/radiology.170.2.2783494.


Positron emission tomography (PET) was used in the follow-up of patients with colorectal malignancies to differentiate between recurrent colorectal tumor and scar. Patients were examined with oxygen-15-labeled water and with fluorine-18-labeled deoxyglucose (FDG). FDG was injected intravenously to assess tumor metabolism. The tracer concentration was quantitatively evaluated by means of a region-of-interest technique and standardized for both injected dose and body volume. Of 29 patients, 21 had recurrent colorectal malignancy, and eight had a nonmalignant mass. All malignancies were seen on the PET cross sections. Nonmalignant lesions had a low FDG accumulation on images obtained 60 minutes after injection. While the tumor-soft tissue ratio was highest shortly after the intravenous injection of FDG, the tumor-scar ratio was highest 60 minutes after injection. It was possible to differentiate tumor from non-malignant tissue with FDG with the use of standardized concentration values and tumor-soft tissue ratios. Imaging with O-15-labeled water gave no additional information.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Cicatrix / diagnostic imaging
  • Colorectal Neoplasms / diagnostic imaging*
  • Colorectal Neoplasms / surgery
  • Diagnosis, Differential
  • Female
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local*
  • Tomography, Emission-Computed*