SNMMI Feature: 4D PET may be cut above the rest for heart scans

Transverse, coronal and sagittal slices and short-, long-vertical-and horizontal-axis images of Rb-18Source: J Nucl Med 2009; 50:1062–1071

A 4D PET imaging reconstruction technique may help improve image quality and reduce noise during cardiac-gated PET scans, according to research presented June 10 at the 59th annual meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) in Miami.

Si Chen, PhD, Tsinghua University in Beijing, China, and colleagues developed the 4D PET reconstruction method that includes respiratory and cardiac motion compensation to understand its efficacy during cardiac PET scans.

The technique works by extracting data from different points during the scan (i.e., when patients take a breath). The researchers said that the new 4D technique takes “crystal-clear” images by using quantitative image data and algorithms that help acquire better images.

"This newly developed 4D image reconstruction algorithm will improve the cardiac PET image quality--enhancing image resolution and reducing noise at the same time--which will make the interpretation of the images by physicians easier and of higher accuracy," Chen, a research scientist, said in an interview. "This will further benefit the diagnostic accuracy of cardiac diseases by PET studies."

The researchers used PET images from cardiac stress tests to evaluate the effect the method had on signal-to-noise ratios. They reported a 15 percent improvement in reconstructed images with the 4D method. In addition to this finding, the researchers found image noise to be reduced by 60 percent compared with conventional imaging methods used during cardiac gating.

Chen said that the new technology will lead to better diagnostic accuracy and improved treatment planning. Chen noted that the technique may also have the ability to lower dose and produce a faster scan. However, the authors cautioned that two to three more years of research will need to be carried out before the technique will be ready for the real-world setting.

"The algorithm is fully compatible with current workflow," Chen summed. "But with the new algorithm, patient scan time or injected dose (or both) can be reduced to a certain extent but the image quality remains the same as that by the image reconstruction algorithm implemented in the current protocols."

Chen added that there will be "absolutely no cost" associated with this technology.