Comparison of ventilation defects quantified by Technegas SPECT and hyperpolarized 129Xe MRI

Nisarg Radadia; Yonni Friedlander; Eldar Priel; Norman B Konyer; Chynna Huang; Mobin Jamal; Troy Farncombe; Christopher Marriott; Christian Finley; John Agzarian; Myrna Dolovich; Michael D Noseworthy; Parameswaran Nair; Yaron Shargall; Sarah Svenningsen

doi:10.3389/fphys.2023.1133334

Comparison of ventilation defects quantified by Technegas SPECT and hyperpolarized ¹²⁹Xe MRI

Front Physiol. 2023 Apr 28:14:1133334. doi: 10.3389/fphys.2023.1133334. eCollection 2023.

Authors

Nisarg Radadia¹, Yonni Friedlander^{2

3}, Eldar Priel^{2

4

5}, Norman B Konyer³, Chynna Huang², Mobin Jamal¹, Troy Farncombe^{6

7}, Christopher Marriott^{6

7}, Christian Finley^{2

4

5}, John Agzarian^{2

4

5}, Myrna Dolovich^{1

2

3}, Michael D Noseworthy^{3

6

8}, Parameswaran Nair^{1

2}, Yaron Shargall^{2

4

5}, Sarah Svenningsen^{1

2

3}

Affiliations

¹ Division of Respirology, Department of Medicine, McMaster University, Hamilton, ON, Canada.
² Firestone Institute for Respiratory Health, St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada.
³ Imaging Research Centre, St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada.
⁴ Division of Thoracic Surgery, St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada.
⁵ Division of Thoracic Surgery, Department of Surgery, McMaster University, Hamilton, ON, Canada.
⁶ Department of Radiology, McMaster University, Hamilton, ON, Canada.
⁷ Department of Nuclear Medicine, St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada.
⁸ Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada.

Abstract

Introduction: The ideal contrast agents for ventilation SPECT and MRI are Technegas and ¹²⁹Xe gas, respectively. Despite increasing interest in the clinical utility of ventilation imaging, these modalities have not been directly compared. Therefore, our objective was to compare the ventilation defect percent (VDP) assessed by Technegas SPECT and hyperpolarized ¹²⁹Xe MRI in patients scheduled to undergo lung cancer resection with and without pre-existing obstructive lung disease. Methods: Forty-one adults scheduled to undergo lung cancer resection performed same-day Technegas SPECT, hyperpolarized ¹²⁹Xe MRI, spirometry, and diffusing capacity of the lung for carbon monoxide (DL_CO). Ventilation abnormalities were quantified as the VDP using two different methods: adaptive thresholding (VDP_T) and k-means clustering (VDP_K). Correlation and agreement between VDP quantified by Technegas SPECT and ¹²⁹Xe MRI were determined by Spearman correlation and Bland-Altman analysis, respectively. Results: VDP measured by Technegas SPECT and ¹²⁹Xe MRI were correlated (VDP_T: r = 0.48, p = 0.001; VDP_K: r = 0.63, p < 0.0001). A 2.0% and 1.6% bias towards higher Technegas SPECT VDP was measured using the adaptive threshold method (VDP_T: 23.0% ± 14.0% vs. 21.0% ± 5.2%, p = 0.81) and k-means method (VDP_K: 9.4% ± 9.4% vs. 7.8% ± 10.0%, p = 0.02), respectively. For both modalities, higher VDP was correlated with lower FEV₁/FVC (SPECT VDP_T: r = -0.38, p = 0.01; MRI VDP_K: r = -0.46, p = 0.002) and DL_CO (SPECT VDP_T: r = -0.61, p < 0.0001; MRI VDP_K: r = -0.68, p < 0.0001). Subgroup analysis revealed that VDP measured by both modalities was significantly higher for participants with COPD (n = 13) than those with asthma (n = 6; SPECT VDP_T: p = 0.007, MRI VDP_K: p = 0.006) and those with no history of obstructive lung disease (n = 21; SPECT VDP_T: p = 0.0003, MRI VDP_K: p = 0.0003). Discussion: The burden of ventilation defects quantified by Technegas SPECT and ¹²⁹Xe MRI VDP was correlated and greater in participants with COPD when compared to those without. Our observations indicate that, despite substantial differences between the imaging modalities, quantitative assessment of ventilation defects by Technegas SPECT and ¹²⁹Xe MRI is comparable.

Keywords: MRI; Technegas SPECT; airflow obstruction; functional lung imaging; hyperpolarized xenon-129; ventilation defects; ventilation imaging.

Grants and funding

This was an investigator-initiated study funded by Cyclomedica Australia Pty Ltd. and The Lung Association. The funders had no role in the design of the study, the collection and analysis of the data, or the preparation of the manuscript.