Contrast-enhanced MRI and PET-CT in the evaluation of patients with suspected local recurrence of rectal carcinoma.

ABSTRACT

PURPOSE: This study aimed to evaluate the role of contrast-enhanced magnetic resonance imaging (MRI) and positron emission tomography-computed tomography (PET-CT) in the assessment of local recurrence of rectal cancer. MATERIALS AND METHODS: Among 200 patients scheduled for CT follow-up, 60 (48 low risk; 12 high risk) were selected due to CT findings suspicious for or suggestive of local recurrence. Patients underwent contrast-enhanced MRI and PET-CT within 2 weeks. Biopsy was considered the gold standard in 39 cases and follow-up at 6 and 12 months in the remaining 21. RESULTS: Local recurrence was confirmed by histology in 15 cases (7 low risk; 8 high risk) and was excluded in 21 cases by long-term follow-up and in 24 by histology. Sensitivity, specificity, positive and negative predictive value and accuracy were 86.7%, 68.9%, 48.1%, 93.9% and 73.3% for contrast-enhanced MRI and 93.3%, 68.9%, 50%, 96.9% and 75% for PET-CT. CONCLUSIONS: Contrast-enhanced MRI and PET-CT can help in the detection of local recurrence of rectal cancer, even though their roles in early detection remains debatable, as the value of these techniques in current surveillance protocols is still to be defined.