June 12, 2013
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Cardiac PET/MR yielded comparable results to PET/CT

New research seeks to demonstrate the value of integrated PET/MR as compared with PET/CT in cardiac applications.

“Although studies in the brain and whole body have shown that PET activity obtained using MR for attenuation correction was comparable to that measured by PET/CT, similar comparisons in myocardium were not performed,” Jeffrey M.C. Lau, MD, PhD, and colleagues wrote in the study abstract.

The study was designed to determine whether myocardial uptake of F-18 fluorodeoxyglucose (FDG) measured by PET using attenuation correction performed by MR was comparable to that obtained by PET/CT, according to the abstract.

The researchers studied 30 patients with no CVD history who were undergoing cancer evaluation. The patients underwent both whole-body PET/CT (Biograph 40, Siemens) and PET/MR (Biograph mMR, Siemens) with F-18 FDG injection administered about 1 hour before PET/CT and 2 hours before PET/MR.

Average measurement of FDG uptake in the left ventricle was nearly identical: 4.68 for PET/MR vs. 4.62 for PET/CT (P=.47).

Results also demonstrated excellent per-patient correlation. The researchers noted a slight overestimation of FDG activity by PET/MR, which may reflect the later imaging time compared with PET/CT, according to data in the abstract.

“Our research demonstrated that cardiac PET assessment for myocardial viability using PET/MR yielded comparable results to PET acquired using PET/CT,” Lau, from the department of cardiology at Washington University in St. Louis, Mo., stated in a press release. “It showed that PET/MR can produce accurate PET quantification when appropriate attenuation correction method is applied.”

These findings provide evidence for the use of PET/MR in a variety of cardiac applications.

“Our research provides the groundwork for future research in cardiac PET/MR imaging,” Lau said in the release. “PET/MR provides powerful cardiac imaging and requires a lower radiation dose than PET/CT. The MRI component, which can be acquired simultaneously as PET, provides excellent anatomic information in imaging scar tissues caused by heart attacks. In particular, our group is most interested in applying the PET/MR technology to evaluate the likelihood of arrhythmia in patients who have had heart attacks.”

Future studies are needed to continue to provide information about the benefits and appropriateness of PET/MR in clinical practice, according to the researchers.

For more information:

Lau JMC. Scientific paper #27. Presented at: the Society of Nuclear Medicine and Molecular Imaging 60th Annual Meeting; June 8-12, 2013; Vancouver, British Columbia.

Disclosure: This study was conducted in conjunction with Siemens Medical Solutions.