# Quantitative MRI-PET Imaging of Pulmonary Fibrosis

> **NIH NIH K25** · MASSACHUSETTS GENERAL HOSPITAL · 2022 · $159,560

## Abstract

Project Summary/Abstract
 The goal of this project is to develop and implement a MR-PET lung imaging tool to accurately quantify
molecular abnormalities associated with pulmonary fibrosis. Idiopathic pulmonary fibrosis (IPF) is a progressive
and ultimately fatal disease with a median survival of less than 4 years from the time of diagnosis. The treatment
options remain limited due to highly variable clinical course and poorly understood pathogenic mechanisms.
Current strategies to diagnose and monitor IPF include lung biopsy, pulmonary function tests that measure global
lung function, and anatomic imaging tools such as high-resolution computed tomography. Yet these methods
are limited in their ability to detect disease early, determine disease activity, provide accurate prognosis or
monitor the therapeutic response. Molecular imaging may be an alternative approach that is more sensitive to
detect early fibrosis and potentially capable of distinguishing new, active fibrosis from stable disease – urgent
and unmet clinical needs. Advancing the capacity of quantitative imaging tools to determine IPF disease activity
would improve patient care and facilitate much-needed drug development. Our central hypothesis is that non-
invasive MR-aided PET imaging of collagen accumulation will allow us to capture the extent of ongoing lung
injury in IPF patients and thus service as a viable disease activity measure. Magnetic resonance (MR) imaging
can provide multiple readouts of morphology, physiology, metabolism, and molecular processes, while positron
emission tomography (PET) offers exquisite sensitivity to interrogate pathobiology. Advanced MR and PET
techniques have had major impacts in oncology, cardiovascular diseases, and neurological disorders. However,
their application to lung imaging has been historically limited because of low proton density and the fast signal
decay due to susceptibility artefacts at air-tissue interfaces for MRI, while PET quantification remains challenging
due to respiratory motion, photon attenuation and regional variations in tissue, air and blood fractions. Recently,
we developed a gallium(Ga)-68 labeled collagen binding PET probe for fibrosis imaging. Ex vivo measurement
showed a 5-fold higher uptake in bleomycin injured fibrotic lungs than controls. However, both in vivo animal
and first-in-human studies showed a PET signal difference of 35-40%. This discrepancy highlights the
importance of motion, attenuation and partial volume correction in PET quantification. Our preliminary simulation
results show that attenuation and motion correction substantially increase the imaging contrast. Recent technical
advances such as parallel imaging, ultra-short time to echo (UTE) and rotating phase encoding have enabled
advanced proton MR imaging of the lung. Thus simultaneous MR-PET promises to improve PET quantification
by using the spatially and temporally correlated MR information to correct for motion, partial volume and photon
attenu...

## Key facts

- **NIH application ID:** 10468922
- **Project number:** 5K25HL148837-03
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** Iris Yuwen Zhou
- **Activity code:** K25 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $159,560
- **Award type:** 5
- **Project period:** 2020-09-25 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10468922

## Citation

> US National Institutes of Health, RePORTER application 10468922, Quantitative MRI-PET Imaging of Pulmonary Fibrosis (5K25HL148837-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10468922. Licensed CC0.

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