Visualization of the airway in infants with MRI using pointwise encoding time reduction with radial acquisition (PETRA)

PURPOSE: To assess airway visibility in infants using pointwise encoding time reduction with radial acquisition (PETRA). MATERIALS AND METHODS: PETRA was obtained in 37 infants (gestational age: 23-43 weeks; postconceptional age: 34-46 weeks) using 3T magnetic resonance imaging (MRI) without respiratory gating. The visibility of the branching point and the airway structures, including the trachea and bronchi, on PETRA was scored by two experienced pediatric radiologists using a four-point scale (0-3). The rates of good visibility (score 3 or 2) were calculated for each airway structure. Interrater agreement was evaluated by intraclass correlation coefficient (ICC). RESULTS: For readers 1 and 2, good visibility was achieved for the branching point of the main bronchi (76% and 95%, respectively), trachea (97% and 95%, respectively), right main bronchus (92% and 92%, respectively), and left main bronchus (97% and 84%, respectively). Lower rates of visibility were achieved for the lobar bronchi. There was substantial agreement (ICC: 0.61-0.79) between the two readers for all the airway structures, except for the branching point at the right upper/middle lobe bronchi, for which there was moderate agreement (ICC: 0.56). CONCLUSION: PETRA has the potential for good airway visibility in infants, particularly for the trachea and main bronchi. LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:839-844.