Exercise-induced bronchoconstriction: reproducibility of hyperpolarized 3He MR imaging

Area of Science:

• Pulmonary Medicine
• Radiology
• Medical Imaging

Background:

• Exercise-induced bronchoconstriction (EIB) significantly impacts respiratory function.
• Accurate imaging is crucial for evaluating EIB and guiding treatment.
• Hyperpolarized helium 3 (HPHe) MR imaging offers detailed lung ventilation assessment.

Purpose of the Study:

• To quantitatively evaluate the interday, interreader, and intersite agreement of HPHe MR imaging in patients with EIB.
• To establish the reproducibility of quantitative measurements derived from HPHe MR images.

Main Methods:

• 13 patients with EIB underwent HPHe MR imaging on two separate days, including baseline, post-exercise challenge, and recovery.
• Imaging was performed at two different sites (A and B).
• Quantitative analysis of lung volume, ventilation defect volume, ventilated volume, and defect number was conducted, alongside qualitative defect localization. Agreement was assessed using intraclass correlation coefficients (ICC) and modified Bland-Altman analysis.

Main Results:

• High interday and interreader agreement (ICC ≥ 0.74 and ≥ 0.82, respectively) were observed for most quantitative measures.
• Lung volume ICC varied between sites (0.60-0.65 at site A vs. 0.83-0.86 at site B).
• Intersite agreement showed specific biases for lung volume, ventilation defect volume, ventilated volume, and defect number.

Conclusions:

• HPHe MR imaging demonstrates good reproducibility for key quantitative measures in EIB patients.
• The established reproducibility metrics can inform the design and interpretation of single- and multicenter studies.
• These findings support the utility of HPHe MR imaging in clinical research for EIB.