title: Ferumoxide-enhanced MRI in patients with colorectal cancer and rising CEA: surgical correlation in early recurrence.
abstract: The purpose of this study was to evaluate the value of Ferumoxide-enhanced magnetic resonance (MR) imaging in the detection of hepatic metastases in high-risk patients treated for colorectal cancer that have rising CEA. We used 19 patients treated previously for colorectal cancer with rising CEA levels underwent an unenhanced T(1)-weighted (T1W), T(2)-weighted (T2W), STIR, and Ferumoxide-enhanced hepatic MRI. Following these studies, a laparotomy was performed and the liver was evaluated by palpation and intraoperative ultrasound. Two observers who were blinded to surgical results evaluated each MR sequence separately. The number of lesions considered highly suspicious for metastatic lesions were determined for each sequence and were compared to the results of surgery. The McNemar test was used to compare the outcomes of the different sequences. MR Imaging was unable to detect small (<5 mm) metastases discovered at surgery. The best non-contrast sequences for detecting metastases were the STIR with 42% sensitivity, 83% specificity and an overall accuracy of 56% and the T1W sequence (sensitivity 38%, specificity 100%, accuracy 57%), which were not significantly different (p 0.4). The noncontrast T2W sequence had a sensitivity of 29% and a specificity of 77% with an overall accuracy of 46%. When all pre contrast scans were grouped together the common sensitivity was 42%, specificity was 77% and accuracy was 54%. The post-ferumoxide T(2)W scans had a sensitivity of 42%, specificity of 85%, and accuracy of 57%, but did not detect any additional lesions. There was no statistical difference between the pre- and post-contrast studies with regard to identifying patients with metastatic disease (p 0.1). In conclusion, we found small hepatic metastases in patients with early signs of recurrent colorectal cancer are difficult to detect on MRI. Ferumoxide-enhanced MRI was unable to detect additional hepatic metastases and performed no better than unenhanced MRI in detecting small hepatic metastasis.
authors.affiliation: Diagnostic Radiology Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892-1182, USA.
authors.forename: B
authors.initials: B
authors.lastname: Said
authors.forename: J A
authors.initials: JA
authors.lastname: McCart
authors.forename: S K
authors.initials: SK
authors.lastname: Libutti
authors.forename: P L
authors.initials: PL
authors.lastname: Choyke
mesh_terms: D000328:Adult; D000368:Aged; D002272:Carcinoembryonic Antigen / Q000097:blood*; D015179:Colorectal Neoplasms / Q000473:pathology; D003287:Contrast Media / Q000008:administration & dosage*; D003911:Dextrans; D005260:Female; D052203:Ferrosoferric Oxide; D006801:Humans; D007089:Image Enhancement; D007501:Iron / Q000008:administration & dosage; D008113:Liver Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000556:secondary* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis*; D010087:Oxides / Q000008:administration & dosage; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D002272:Carcinoembryonic Antigen; D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide