CT ventilation imaging derived from breath hold CT exhibits good regional accuracy with Galligas PET

Enid M Eslick; John Kipritidis; Denis Gradinscak; Mark J Stevens; Dale L Bailey; Benjamin Harris; Jeremy T Booth; Paul J Keall

doi:10.1016/j.radonc.2017.12.010

CT ventilation imaging derived from breath hold CT exhibits good regional accuracy with Galligas PET

Radiother Oncol. 2018 May;127(2):267-273. doi: 10.1016/j.radonc.2017.12.010. Epub 2017 Dec 28.

Authors

Enid M Eslick¹, John Kipritidis², Denis Gradinscak³, Mark J Stevens⁴, Dale L Bailey⁵, Benjamin Harris⁶, Jeremy T Booth⁴, Paul J Keall⁷

Affiliations

¹ Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Camperdown, Australia.
² Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Camperdown, Australia; Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia.
³ Department of Nuclear Medicine, Royal North Shore Hospital, Australia.
⁴ Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia; Sydney Medical School - Northern, University of Sydney, Australia.
⁵ Department of Nuclear Medicine, Royal North Shore Hospital, Australia; Faculty of Health Sciences, University of Sydney, Lidcombe, Australia.
⁶ Sydney Medical School - Northern, University of Sydney, Australia; Department of Respiratory Medicine, Royal North Shore Hospital, Australia.
⁷ Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Camperdown, Australia. Electronic address: http://sydney.edu.au/medicine/radiation-physics.

PMID: 29290405
DOI: 10.1016/j.radonc.2017.12.010

Abstract

Background and purpose: CT ventilation imaging (CTVI) derived from four dimensional CT (4DCT) has shown only moderate spatial accuracy in humans due to 4DCT image artefacts. Here we assess the accuracy of an improved CTVI using high quality exhale/inhale breath-hold CT (BHCT).

Materials and methods: Eighteen lung cancer patients underwent exhale/inhale BHCT, 4DCT and Galligas PET ventilation scans in a single imaging session. For each BHCT and 4DCT scan, we performed deformable image registration (DIR) between the inhale and exhale phase images to quantify ventilation using three published metrics: (i) breathing induced lung density change, CTVI_DIR-HU (ii) breathing induced volume change CTVI_DIR-Jac and (iii) the regional air-tissue product, CTVI_HU Spatial accuracy was reported as the voxel-wise Spearman correlation r between CTVI and Galligas PET.

Results: For BHCT-based CTVIs (N = 16), the CTVI_DIR-HU, CTVI_DIR-Jac and CTVI_HU methods yielded mean (range) r values of 0.67 (0.52-0.87), 0.57 (0.18-0.77) and 0.49 (0.14-0.75) respectively. By comparison the 4DCT-based CTVIs (n = 14) had values of 0.32 (-0.04 to 0.51), 0.16 (-0.31 to 44) and 0.49 (0.20-0.77) respectively.

Conclusions: High quality CT imaging is a key requirement for accurate CT ventilation imaging. The use of exhale/inhale BHCT can improve the accuracy of CTVI for human subjects.

Keywords: CT ventilation imaging; Deformable image registration; Galligas PET; Lung cancer.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aged
Artifacts
Breath Holding
Exhalation / physiology
Female
Four-Dimensional Computed Tomography / methods*
Humans
Inhalation / physiology
Lung Neoplasms / diagnostic imaging*
Lung Neoplasms / physiopathology
Male
Middle Aged
Positron-Emission Tomography / methods*
Prospective Studies
Pulmonary Ventilation / physiology
Radiotherapy Planning, Computer-Assisted / methods