Journal Article

More accessible functional lung imaging: non-contrast CT-ventilation demonstrates strong association and agreement with PET-ventilation

Eikelis, Nina, Byrne, Hilary L., Pirakalathanan, Piraveen, Fouras, Andreas, Dusting, Jonathan, Keall, Paul J.

2025

Overview

Background Computed Tomography (CT) ventilation imaging (CTVI) is an emerging ventilation imaging technique. CTVI implementations have been widely validated against alternative ventilation imaging techniques but have been limited to clinical research only. The first CTVI commercial product, CT LVAS (4DMedical, Melbourne, Australia), was recently released enabling its use in clinical practice. This study quantitatively compares ventilation images from CT LVAS and previously validated research CTVI algorithms to Galligas PET ventilation. Methods 16 patients with Galligas PET and paired inhale/exhale breath-hold CT images were taken from a publicly available dataset on The Cancer Imaging Archive. Ventilation images were produced using CT LVAS and two previously published algorithms: (1) utilising the Hounsfield Unit difference (CTVI_HU); and (2) utilising the Jacobian determinant (CTVI_Jac). CTVI images were compared to the reference standard Galligas PET using Bland-Altman analysis of lobar ventilation, voxel-wise Spearman correlation, and Dice similarity coefficient (DSC) of regions of interest representing the top 85% and 15% of ventilation function. Results Bland-Altman analysis showed overall bias of < 0.01% for all CTVI methods (95% confidence interval: ±7.4% for CT LVAS, ± 9.1% for CTVI_HU, ± 7.9% for CTVI_Jac). The mean Spearman correlation between CTVI and Galligas PET was 0.61 ± 0.14 ( p  < 0.01) for CT LVAS, 0.68 ± 0.10 ( p  < 0.01) for CTVI_HU, and 0.57 ± 0.15 ( p  < 0.01) for CTVI_Jac. The mean DSC for the top 85% was 0.91 ± 0.03 for CT LVAS, 0.92 ± 0.02 for CTVI_HU, and 0.91 ± 0.03 for CTVI_Jac, with the DSC for CTVI_HU significantly higher than the other two CTVI methods. The DSC for the top 15% was 0.47 ± 0.17 for CT LVAS, 0.53 ± 0.16 for CTVI_HU, and 0.47 ± 0.18 for CTVI_Jac. Conclusions In a comparison to Galligas PET ventilation imaging, CT LVAS performs similarly to previous CTVI methods. Bland-Altman analysis for quantification of lobar ventilation demonstrates negligible bias. Mean voxel-wise Spearman correlations are moderate to good. DSC of functionally thresholded lung regions are similar for all CTVI methods. These results warrant further investigation of CT LVAS as a readily available ventilation imaging tool in disease characterisation, lung health assessment, and surgical and targeted treatment planning. Trial registration Australian New Zealand Clinical Trials Registry (ANZCTR) registration number ACTRN12612000775819, registered on 23/07/2012.

• Publisher: BioMed Central,BioMed Central Ltd,Nature Publishing Group,BMC
• Subject: Aged / Algorithms / Bias / Cancer therapies / Clinical trials / Computed tomography / Correlation / CT imaging / Datasets / Diagnosis / Diagnostic imaging / Ethics / Female / Functional imaging / Humans / Imaging techniques / Lung / Lung - diagnostic imaging / Lung - physiology / Lung - physiopathology / Lung diseases / Lung Neoplasms - diagnostic imaging / Lung Neoplasms - physiopathology / Lungs / Magnetic resonance imaging / Male / Medical imaging / Medicine / Medicine & Public Health / Middle Aged / Nanoparticles / Nuclear medicine / Pneumology/Respiratory System / Positron emission / Positron-Emission Tomography - methods / Pulmonary Ventilation - physiology / Radiation therapy / Registration / Systematic review / Tomography / Tomography, X-Ray Computed - methods / Tomography, X-Ray Computed - standards / Ventilation