MRI is better than PET for detecting small metastatic lesions in the liver


Contrast enhanced MRI should be the imaging method of choice for determining if patients with gastrointestinal cancer have disease that has spread into their liver, a new study shows.

The study compared FDG PET to MRI and found that both diagnosed cancer metastases, however, MRI was better able to detect more and smaller lesions in the patients, said Dushyant Sahani, MD, one of the authors of the study.

The study included 30 patients with 97 metastatic lesions. MRI detected 79 of the lesions, 33 of which were less than 1 cm. PET detected 65 of the 97 lesions, 12 of which measured less than 1 cm. The number of lesions and the size of lesions are critical, said Dr. Sahani, because that is what determines treatment. "Per lesion analysis showed that MRI had an accuracy rate of 75.5% compared to 64.1% for PET," said Dr. Sahani.

Dr. Sahani noted that the MRI contrast agent that was used in the study was specifically designed for imaging the liver. The contrast agent stayed in the liver for a couple of hours, allowing the radiologist to obtain a higher resolution image and thinner image slices, he said. The contrast agent that was used in the study is not currently available, however, there are other liver-specific agents, which are awaiting approval from the Food and Drug Administration, Dr. Sahani said.

The study will be presented on May 6 at the American Roentgen Ray Society Annual Meeting in Miami Beach, FL.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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