Multiparametric Lung MRI With Diffusion-Weighted Imaging in Lung-RADS 4 Lesion Characterization

This study evaluates whether multiparametric chest magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI), performed without any contrast material, can distinguish malignant from benign lung lesions that were assigned Lung-RADS category 4 on a standard-of-care lung cancer screening low-dose CT.

Participants who have a Lung-RADS 4 lesion on screening CT undergo one non-contrast research MRI of the chest at 3.0 Tesla. The MRI is added to standard care; no standard-of-care imaging, biopsy, or treatment is withheld or replaced, and the research MRI is not used for clinical decision making. Participants then continue routine clinical management, and the final nature of the lesion is established from pathology or microbiology when tissue is obtained, or otherwise from at least 24 months of clinical and imaging follow-up.

The primary measure is the sensitivity and specificity of multiparametric MRI against that final diagnosis. Secondary measures include whether DWI alone performs as well as the full MRI protocol, how MRI compares with PET/CT in participants who had PET/CT as part of their care, and quantitative MRI thresholds (apparent diffusion coefficient, lesion-to-spinal-cord signal intensity ratio, native T1 and T2).

This is an exploratory pilot and feasibility study. No formal power calculation was performed; the sample size is intended to support feasibility assessment, protocol optimization, and preliminary estimates of diagnostic performance.