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Figure
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Figure
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History:
Status-post sigmoid colon resection and increasing CEA level. CT
examination was performed (Figure 1) demonstrating soft-tissue
structure adjacent to the colon anastomosis (arrow), which may
represent recurrent tumor or fibrosis. The patient was referred to Main
Street Radiology for a PET scan.
Findings:
Axial (Figure 2) and sagittal (Figure 3) PET images demonstrate
hypermetabolic activity (arrows) corresponding to the CT finding,
compatible with local recurrent tumor. There was no evidence of
metastatic disease elsewhere.
Discussion:
PET scanning has been widely established as the most accurate
non-invasive test for staging and re-staging colorectal carcinoma. For
hepatic metastasis, PET is superior to CT, with sensitivity of 88% vs.
38% and specificity of 100% vs. 97% (Radiology 1998; 206:755-760). PET
is also highly accurate at demonstrating recurrent colorectal cancer
in patients who have indeterminate findings at CT or MR, with
sensitivity and specificity for local pelvic recurrence at 95% and 97%
respectively (J Nucl Med 2000; 41:1177-1189). PET allows
differentiation of recurrence from fibrosis, superior to CT, with
sensitivity of 93% vs. 60%, and specificity of 97% vs. 72 % (Eur J
Surg Oncol 1995; 21:517-522).
PET has been approved for Medicare
reimbursement for the diagnosis, staging, and restaging of colorectal
cancer. During the initial staging of disease, PET plays a valuable
role in determining the true extent of disease, and to help plan
surgical and non-surgical therapeutic procedures. PET is also valuable
in re-evaluating patients following treatment, with or without rising
CEA level.
PET offers information not available
through other type of diagnostic studies. Since PET tracer FDG is
taken up at a cellular level, functional images are generated that
complement the traditional anatomic images generated through CT and
MRI studies.
Clinical Case
Studies
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Main
Street Radiology
PET
Clinical
Case Studies |
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