Evidence map›Paper›PMID 38049611›Full record

ArticleEJNMMI physics2023

Optimisation of the air fraction correction for lung PET/CT: addressing resolution mismatch.

Francesca Leek, Cameron Anderson, Andrew P Robinson, Robert M Moss, Joanna C Porter, Helen S Garthwaite, Ashley M Groves, Brian F Hutton, Kris Thielemans

Open access · goldAbstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in EJNMMI physics, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
0.2field-weighted citation impact, top 38% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed, 1 citations in OpenAlex.

  1. Molecular Imaging of Pulmonary Fibrosis.Journal of nuclear medicine : official publication, Society of Nuclear Medicine · 2025
    Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors at 3 institutions in 1 country.

Francesca LeekInstitute of Nuclear Medicine, University College London Hospitals NHS Trust, London, UK. francesca.leek.09@ucl.ac.uk.ORCID http://orcid.org/0000-0003-2919-1894
Cameron AndersonInstitute of Nuclear Medicine, University College London Hospitals NHS Trust, London, UK.
Andrew P RobinsonNuclear Medicine Metrology, National Physical Laboratory, Teddington, UK.
Robert M MossDepartment of Medical Physics and Biomedical Engineering, University College London, London, UK.
Joanna C PorterUCL Respiratory, University College London and Interstitial Lung Disease Service, University College London Hospitals NHS Trust, London, UK.
Helen S GarthwaiteUCL Respiratory, University College London and Interstitial Lung Disease Service, University College London Hospitals NHS Trust, London, UK.
Ashley M GrovesInstitute of Nuclear Medicine, University College London Hospitals NHS Trust, London, UK.
Brian F HuttonInstitute of Nuclear Medicine, University College London Hospitals NHS Trust, London, UK.
Kris ThielemansInstitute of Nuclear Medicine, University College London Hospitals NHS Trust, London, UK.
University College London Hospitals NHS Foundation Trust · GBNational Physical Laboratory · GBUniversity College London · GB

Funding

Engineering and Physical Sciences Research Council BIDS3000030921Engineering and Physical Sciences Research Council EP/T026693/1Engineering and Physical Sciences Research Council EP/T517628/1EPSRC Centre for Doctoral Training in Medical Imaging EP/S021930/1GlaxoSmithKline BIDS3000035300
6 · The paper itself

Abstract

backgroundIncreased pulmonary [Formula: see text]F-FDG metabolism in patients with idiopathic pulmonary fibrosis, and other forms of diffuse parenchymal lung disease, can predict measurements of health and lung physiology. To improve PET quantification, voxel-wise air fractions (AF) determined from CT can be used to correct for variable air content in lung PET/CT. However, resolution mismatches between PET and CT can cause artefacts in the AF-corrected image.

methodsThree methodologies for determining the optimal kernel to smooth the CT are compared with noiseless simulations and non-TOF MLEM reconstructions of a patient-realistic digital phantom: (i) the point source insertion-and-subtraction method, [Formula: see text]; (ii) AF-correcting with varyingly smoothed CT to achieve the lowest RMSE with respect to the ground truth (GT) AF-corrected volume of interest (VOI), [Formula: see text]; iii) smoothing the GT image to match the reconstruction within the VOI, [Formula: see text]. The methods were evaluated both using VOI-specific kernels, and a single global kernel optimised for the six VOIs combined. Furthermore, [Formula: see text] was implemented on thorax phantom data measured on two clinical PET/CT scanners with various reconstruction protocols.

resultsThe simulations demonstrated that at [Formula: see text] iterations (200 i), the kernel width was dependent on iteration number and VOI position in the lung. The [Formula: see text] method estimated a lower, more uniform, kernel width in all parts of the lung investigated. However, all three methods resulted in approximately equivalent AF-corrected VOI RMSEs (<10%) at [Formula: see text]200i. The insensitivity of AF-corrected quantification to kernel width suggests that a single global kernel could be used. For all three methodologies, the computed global kernel resulted in an AF-corrected lung RMSE <10%  at [Formula: see text]200i, while larger lung RMSEs were observed for the VOI-specific kernels. The global kernel approach was then employed with the [Formula: see text] method on measured data. The optimally smoothed GT emission matched the reconstructed image well, both within the VOI and the lung background. VOI RMSE was <10%, pre-AFC, for all reconstructions investigated.

conclusionsSimulations for non-TOF PET indicated that around 200i were needed to approach image resolution stability in the lung. In addition, at this iteration number, a single global kernel, determined from several VOIs, for AFC, performed well over the whole lung. The [Formula: see text] method has the potential to be used to determine the kernel for AFC from scans of phantoms on clinical scanners.

Indexed as

Air fraction correctionLung imagingPerturbationPET/CTQuantificationResolution

Identifiers

PMID38049611
PMCPMC10695904
OpenAlexW4389322510

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.