Second-order Texture Measurements of (3)He Ventilation MRI: Proof-of-concept Evaluation of Asthma Bronchodilator Response.

Abstract

RATIONALE AND OBJECTIVES:

(3)He magnetic resonance imaging (MRI) can be used to quantify functional responses to asthma therapy and provocation. Ventilation imaging offers quantitative information beyond ventilation defects that have not yet been exploited. Therefore, our objective was to evaluate hyperpolarized (3)He MRI ventilation defect percent (VDP) and compare this and pulmonary function measurements to ventilation image texture features and their changes post-bronchodilator administration in patients with asthma.

MATERIALS AND METHODS:

Volunteers with a diagnosis of asthma provided written informed consent to an ethics board-approved protocol and underwent pulmonary function tests and MRI before and after salbutamol inhalation. MR images were analyzed using VDP, and their texture was evaluated via gray-level run-length matrices. These texture classifiers were compared to VDP in responders to bronchodilation based on VDP (VDP responders) and forced expiratory volume in 1 s (FEV1) (FEV1 responders).

RESULTS:

In total, 47 patients with asthma (18 males 39 ± 13 years, FEV1 = 79 ± 21%) reported significantly improved FEV1, FEV1/forced vital capacity (FVC), residual volume (RV)/total lung capacity (TLC) (all P = .0001) and VDP (P = .01) post-salbutamol. Post-salbutamol, VDP responders and nonresponders to salbutamol were significantly different for coarse-texture features including long-run emphasis (LRE) and long-run, low gray-level emphasis (LRLGE, both P < .05) and for FEV1 responders to salbutamol, there was significantly different long-run, high gray-level emphasis (LRHGE, P = .04). There were significant relationships for VDP with LRE (R = .50, P = .0003), LRLGE (R = .34, P = .02), and LRHGE (R = .56, P = .0001). Receiver operating characteristic curves showed VDP with the strongest performance (AUC = .92), followed by coarse-texture classifier LRHGE (AUC = .83), FEV1 (AUC = .80), LRE (AUC = .66), FVC (AUC = .58), and LRLGE (AUC = .42).

CONCLUSIONS:

In patients with asthma, differences in ventilation patchiness post-salbutamol can be quantified using coarse-texture classifiers that are significantly different in bronchodilator responders.

• Authors: Nanxi Zha, Damien Pike, Sarah Svenningsen, Dante P I Capaldi, David G McCormack, Grace Parraga
• Journal: Academic radiology (Acad Radiol) Vol. 23 Issue 2 Pg. 176-85 (Feb 2016) ISSN: 1878-4046 [Electronic] United States
• PMID: 26601971 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Chemical References

• Bronchodilator Agents
• Isotopes
• Helium
• Albuterol

Topics

• Administration, Inhalation
• Adult
• Albuterol (administration & dosage)
• Area Under Curve
• Asthma (diagnostic imaging, physiopathology)
• Bronchial Provocation Tests (methods)
• Bronchodilator Agents (administration & dosage)
• Female
• Forced Expiratory Volume (drug effects)
• Helium
• Humans
• Image Enhancement (methods)
• Isotopes
• Lung (diagnostic imaging, drug effects)
• Magnetic Resonance Imaging (methods)
• Male
• Maximal Midexpiratory Flow Rate (drug effects)
• Middle Aged
• ROC Curve
• Residual Volume (drug effects)
• Respiration (drug effects)
• Respiratory Function Tests (methods)
• Signal-To-Noise Ratio
• Spirometry (methods)
• Total Lung Capacity (drug effects)
• Vital Capacity (drug effects)