New imaging method distinguishes inflammation from lung fibrosis

A new SPECT/CT imaging approach can accurately differentiate inflammation from fibrosis in interstitial lung disease (ILD) patients, according to new research presented at the Society of Nuclear Medicine and Molecular Imaging 2026 Annual Meeting. This molecular imaging technique has the potential to determine which patients would benefit from anti-inflammatory treatments and which would likely only experience harmful side effects.

ILD includes more than 200 different types of lung conditions, and affects approximately 650,000 people in the United States, resulting in an estimated 25,000 to 30,000 deaths per year. Differentiating between fibrotic scarring and inflammation stages of disease is critical so that physicians can determine what treatment is best for the patient.

We saw during the Covid-19 pandemic -- when all patients with the infection had inflammation that anti-inflammatory treatments were highly effective. While current imaging techniques can provide a structural view of fibrosis in the lungs, there is no reliable, non-invasive way to identify inflammation. A tool that could detect inflammation in ILD patients could help pinpoint those most likely to respond to anti-inflammatory therapy."

Druin Burch, consultant physician, John Radcliffe Hospital in Oxford, United Kingdom

Researchers investigated the molecular imaging agent ⁹⁹ᵐTc-maraciclatide, which visualizes the formation of new blood vessels a cardinal feature of inflammatory disease. A total of 15 patients, five with idiopathic pulmonary fibrosis, five with fibrotic hypersensitivity pneumonitis, and five healthy controls, underwent ⁹⁹ᵐTc-maraciclatide SPECT/CT. Nuclear medicine physicians and thoracic radiologists classified the images based on radiological patterns, standardized uptake values, and target-to-background ratios.

The healthy controls showed minimal tracer uptake in the lungs, whereas both groups of patients with ILD demonstrated distinct uptake. The target-to-background ratio was also numerically higher in the lung disease cohorts compared to the healthy controls.

"Being able to differentiate the fibrotic and inflammation stages of ILD is not just beneficial to inform treatment decisions, but also for the development new therapies," said Burch. "This approach has the potential to unlock a wide range of anti-inflammatory drugs for ILD."

A Phase 3 study in a larger patient population is required before this imaging approach can be used outside the research setting. As ⁹⁹ᵐTc‑maraciclatide has received FDA Fast Track designation for imaging ILD, it could become available to patients within two years of initiating a Phase 3 trial.