PET/MRI Plus CT Helps Determine Colorectal Cancer Treatment

Use of integrated whole-body PET/MRI may aid in the selection of treatment strategies for patients with colorectal cancer, according to a study published in the American Journal of Roentgenology.

Researchers from Korea sought to determine if adding PET and MRI would add clinical value compared with the conventional contrast-enhanced multidetector computed tomography (CECT) alone when evaluating patients with colorectal cancer.

Fifty-one patients with colorectal cancer underwent 18F-FDG PET/MRI and CECT within a 90-day interval between October 2012 and August 2013. The probability of malignancy was assessed on a 5-point scale, and two reviewers in consensus performed evaluations regarding the value, if any, added by PET/MRI to CECT for lesion detection, characterization, and treatment strategy recommendations. Lesions were examined through histopathological findings and imaging, with follow-up. When pulmonary metastatic nodules were detected by chest CT scan, they were evaluated by two reviewers using PET/MRI.[[{"type":"media","view_mode":"media_crop","fid":"44895","attributes":{"alt":"","class":"media-image media-image-right","id":"media_crop_3123181460550","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"5063","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 128px; width: 171px; border-width: 0px; border-style: solid; margin: 1px; float: right;","title":"©Spectral-Design/Shutterstock.com","typeof":"foaf:Image"}}]]

The results showed that PET/MRI did add value to CECT for 14 of 51 patients (27.5%). Twelve of these patients (23.5%) had better characterization and two of the 51 (3.9%) had additional detection of extracolonic lesions. This resulted in 11 of the 51 patients (21.6%) experiencing a change in treatment strategy. The authors noted that PET/MRI was significantly superior to CT in depicting colorectal cancer, and that the rate of detection of pulmonary metastatic nodules with PET/MRI was 52.9% (nine of 17).

Although the value of adding PET/MRI to CECT was limited in relation to detecting small pulmonary metastatic modules, the authors concluded that the imaging did add value in the detection of metastatic lesions and characterization of indeterminate lesions overall, suggesting that PET/MRI may aid in the selection of more appropriate treatment strategies.