Comparison of Computed Tomography Ventilation Imaging and Hyperpolarized 3 He Magnetic Resonance Imaging in Patients With Lung Cancer.
Shinya Ito, Yujiro Nakajima, Yukio Fujita et al.
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In 30 seconds
This phase 2 comparative study assessed computed tomography ventilation imaging (CTVI) against hyperpolarized 3He MRI in 27 patients with non-small cell lung cancer undergoing functional-avoidance radiotherapy. CTVI was retrospectively generated from four-dimensional CT, and dose-function metrics were compared between imaging methods. Correlations were strong for functional V20Gy and functional mean lung dose (0.80 to 0.82); the mean difference in functional V20Gy was <1%, although patient-level agreement varied. Higher functional V20Gy was observed among patients with a clinically meaningful lung cancer subscale decline, but outcome comparisons were small and not consistently statistically significant.
Key findings
- Correlations between CTVI- and 3He MRI-based dose-function metrics were 0.80 to 0.82 for functional V20Gy and functional mean lung dose.
- For functional V20Gy, the mean difference was <1%, with 95% limits of agreement of 8% to 10%.
- Among evaluable patients, those with a ≥3-point lung cancer subscale decline had higher fV20Gy (CTVI: 28.2% vs 21.9%, P = .05; 3He MRI: 26.2% vs 22.3%, P = 0.24).
- Patients with grade ≥2 radiation pneumonitis had higher fV20Gy values, but comparisons were not statistically significant.
Why it matters
Functional avoidance radiotherapy depends on identifying well-ventilated lung regions and estimating their radiation exposure. The strong correlations and small average bias suggest CTVI may provide a practical ventilation surrogate when comparing dose-function metrics with 3He MRI. However, the limits of agreement indicate that similar average results do not guarantee close agreement for every patient.
What to keep in mind
The study included 27 patients, with only 20 evaluable for lung cancer subscale outcomes and four with grade ≥2 radiation pneumonitis. Patient-level agreement varied, and outcome comparisons were limited.