SNM: PET, motion-frozen tech combo improves cardiac studies
A study presented Monday at the 2009 SNM meeting in Toronto demonstrated that combining high-definition PET and motion-frozen technologies delivers exceptional image quality and can significantly change the diagnosis of patients with heart disease.

The motion-frozen technology adds physiological details that were previously unable to be imaged by physicians, according to the researchers.

"Our study shows that combining these technologies revealed defects that otherwise would not have been imaged," said Ludovic Le Meunier, MD, senior scientist at Siemens Healthcare Molecular Imaging in Hoffman Estates, Ill., and Cedars-Sinai Medical Center in Los Angeles. "While our study was limited to a specific imaging test, the findings could indicate a whole new level of quality in cardiac imaging and could significantly advance the ways that physicians diagnose and treat heart disease."

PET myocardial viability assessments are widely prescribed for patients with heart disease to assess the myocardium, and help physicians make decisions about treatment. However, the authors said that cardiac PET image quality can be limited by the physiological motion of the heart, which can distort images, and by certain shortcomings in PET scanners.

For the study, images of the heart were obtained by combining a Siemens Healthcare PET system with Cedars-Sinai's motion-frozen technology. The high-definition PET system uses "spatially variant detector spatial response" technology when the image is reconstructed, which corrects for distortion and noise that can make images hard to interpret.

The motion-frozen technology, originally developed by Piotr Slomka, PhD, a research scientist at Cedars-Sinai, is an image-processing technique that compensates for the motion of the beating heart, removing unwanted blur and thus improving the diagnostic value of imaging.

In the study, the combined technologies were used to obtain images of 10 patients who were referred for PET myocardial viability assessments at Cedars-Sinai. For these patients, the diagnostic results were modified after imaging with the new technologies-sometimes drastically, the researchers said. By combining PET and motion-frozen technology, the resulting cardiac PET images provided physiological details that were previously hidden from physicians.

The researchers are investigating expanding this technique to correct for the distortions that arise from respiratory motion during imaging. Preliminary results of a separate study (Abstract 1474, "Motion frozen dual gated cardiac and respiratory PET images") were also presented at the SNM meeting this week.