New CT technique differentiates types of lung damage

ANN ARBOR, MI — A research team from the University of Michigan (U-M) Medical School have developed a new approach to lung scanning that could improve the diagnosis and treatment of chronic obstructive pulmonary disease (COPD).

Approximately 24 million people in the U.S. suffer from COPD, and it is the third-highest cause of death in the country.

In a new paper published online first in Nature Medicine, the team reports on a technique called parametric response mapping, or PRM, which was used to analyze computed tomography (CT) scans of the lungs of patients with COPD, who took part in the national COPDGene study funded by the National Heart, Lung and Blood Institute.

According to the researchers, the PRM technique for analyzing CT scans allows them to better distinguish between early-stage damage to the small airways of the lungs, and more severe damage known as emphysema. The study also shows that the overall severity of a patient’s disease, as measured with PRM, matches closely with the patient’s performance on standard lung tests based on breathing ability.

“Essentially, with the PRM technique, we’ve been able to tell sub-types of COPD apart, distinguishing functional small airway disease or fSAD from emphysema and normal lung function,” says Brian Ross, Ph.D., the Roger A. Berg Research Professor of radiology, professor of biological chemistry and senior author of the new paper. “We believe this offers a new path to more precise diagnosis and treatment planning, and a useful tool for precisely assessing the impact of new medications and other treatments.”

“In the last decade, CT scan techniques for imaging COPD have improved steadily, but PRM is the missing link – giving us a robust way to see small airway disease and personalize treatment,” says Ella Kazerooni, M.D., M.S., FACS, a radiology professor who leads the lung imaging program at U-M and is a member of the COPDGene trial.

The PRM technique was originally developed to show the response of brain tumors to treatment. This study has shown that it can also identify COPD specific changes in three-dimensional lung regions over time. A U-M spinoff company, Imbio, has already licensed U-M’s patents on the PRM technique, and is developing the technology for use in early prediction of treatment response of brain tumors and other cancers. Now Imbio has also begun developing PRM for COPD subtype diagnosis and tracking.

“PRM can also help to track COPD progression or response to treatment over time,” says lead author Craig Gabán, assistant professor of radiology.