Hyperpolarized 3helium magnetic resonance ventilation imaging of the lung in cystic fibrosis:: comparison with high resolution CT and spirometry

The purpose of this study was to compare hyperpolarized (3-)helium magnetic resonance imaging (He-3 MRI) of the lungs in adults with cystic fibrosis (CF) with high-resolution computed tomography (HRCT) and spirometry. Eight patients with stable CF prospectively underwent He-3 MRI, HRCT, and spirometry within 1 week. Three-dimensional (3D) gradient-echo sequence was used during an 18-s breath-hold following inhalation of hyperpolarized He-3. Each lung was divided into six zones; He-3 MRI was scored as percentage ventilation per lung zone. HRCT was scored using a modified Bhalla scoring system. Univariate (Spearman rank) and multivariate correlations were performed between He-3 MRI, HRCT, and spirometry. Results are expressed as mean +/- SD (range). Spirometry is expressed as percent predicted. There were four men and four women, mean age=31.9 +/- 9 (20-46). Mean forced expiratory volume in 1 s (FEV)(1)=52%+/- 29 (27-93). Mean He-3 MRI score=74%+/- 25 (55-100). Mean HRCT score=48.8 +/- 24 (13.5-83). The correlation between He-3 MRI and HRCT was strong (R=+/- 0.89, p < 0.001). Bronchiectasis was the only independent predictor of He-3 MRI; He-3 MRI correlated better with FEV1 and forced vital capacity (FVC) (R=0.86 and 0.93, p < 0.01, respectively) than HRCT (R=+/- 0.72 and +/- 0.81, p < 0.05, respectively). This study showed that He-3 MRI correlates strongly with structural HRCT abnormalities and is a stronger correlate of spirometry than HRCT in CF.