Automated assessment of functional lung imaging with 68 Ga-ventilation/perfusion PET/CT using iterative histogram analysis

McIntosh, Lachlan, Jackson, Price, Hardcastle, Nicholas, Bressel, Mathias, Kro, Tomas, Callahan, Jason W., Steinfort, Daniel, Bucknell, Nicholas, Hofman, Michael S., and Siva, Shankar (2021) Automated assessment of functional lung imaging with 68 Ga-ventilation/perfusion PET/CT using iterative histogram analysis. EJNMMI Physics, 8 (1). 23.

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Purpose: Functional lung mapping from Ga68-ventilation/perfusion (V/Q) PET/CT, which has been shown to correlate with pulmonary function tests (PFTs), may be beneficial in a number of clinical applications where sparing regions of high lung function is of interest. Regions of clumping in the proximal airways in patients with airways disease can result in areas of focal intense activity and artefact in ventilation imaging. These artefacts may even shine through to subsequent perfusion images and create a challenge for quantitative analysis of PET imaging. We aimed to develop an automated algorithm that interprets the uptake histogram of PET images to calculate a peak uptake value more representative of the global lung volume.

Methods: Sixty-six patients recruited from a prospective clinical trial underwent both V/Q PET/CT imaging and PFT analysis before treatment. PET images were normalised using an iterative histogram analysis technique to account for tracer hotspots prior to the threshold-based delineation of varying values. Pearson’s correlation between fractional lung function and PFT score was calculated for ventilation, perfusion, and matched imaging volumes at varying threshold values.

Results: For all functional imaging thresholds, only FEV1/FVC PFT yielded reasonable correlations to image-based functional volume. For ventilation, a range of 10–30% of adapted peak uptake value provided a reasonable threshold to define a volume that correlated with FEV1/FVC (r = 0.54–0.61). For perfusion imaging, a similar correlation was observed (r = 0.51–0.56) in the range of 20–60% adapted peak threshold. Matched volumes were closely linked to ventilation with a threshold range of 15–35% yielding a similar correlation (r = 0.55–0.58).

Conclusions: Histogram normalisation may be implemented to determine the presence of tracer clumping hotspots in Ga-68 V/Q PET imaging allowing for automated delineation of functional lung and standardisation of functional volume reporting.

Item ID: 75273
Item Type: Article (Research - C1)
ISSN: 2197-7364
Keywords: Delineation, Gallium 68, Regional lung function, V/Q PET/CT
Copyright Information: © The Author(s). 2021 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit
Funders: National Health and Medical Research Council of Australia (NHMRC)
Projects and Grants: NHMRC APP1038399
Date Deposited: 17 Aug 2022 01:04
FoR Codes: 32 BIOMEDICAL AND CLINICAL SCIENCES > 3202 Clinical sciences > 320206 Diagnostic radiography @ 50%
51 PHYSICAL SCIENCES > 5105 Medical and biological physics > 510502 Medical physics @ 50%
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