Description:
<jats:sec><jats:title>Background</jats:title><jats:p>Ultrashort-echo-time (UTE) sequences have been developed to overcome technical limitations of pulmonary magnetic resonance imaging (MRI). Recently, it has been shown that UTE sequences with breath-hold allow rapid image acquisition with sufficient image quality. However, patients with impaired respiration require alternative acquisition strategies while breathing freely.</jats:p></jats:sec><jats:sec><jats:title>Purpose</jats:title><jats:p>To compare the diagnostic performance of free-breathing three-dimensional (3D)-UTE sequences with different trajectories based on pulmonary imaging of immunocompromised patients.</jats:p></jats:sec><jats:sec><jats:title>Material and Methods</jats:title><jats:p>In a prospective study setting, two 3D-UTE sequences performed in free-breathing and exploiting non-Cartesian trajectories—one using a stack-of-spirals and the other exploiting a radial trajectory—were acquired at 3 T in patients undergoing hematopoietic stem cell transplantation. Two radiologists assessed the images regarding presence of pleural effusions and pulmonary infiltrations. Computed tomography (CT) was used as reference.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>A total of 28 datasets, each consisting of free-breathing 3D-UTE MRI with the two sequence techniques and a reference CT scan, were acquired in 20 patients. Interrater agreement was substantial for pulmonary infiltrations using both sequence techniques (κ = 0.77 − 0.78). Regarding pleural effusions, agreement was almost perfect in the stack-of-spirals (κ = 0.81) and moderate in the radial sequence (κ = 0.59). No significant differences in detectability of the assessed pulmonary pathologies were observed between both 3D-UTE sequence techniques ( P > 0.05), and their level of agreement was substantial throughout (κ = 0.62–0.81). Both techniques provided high sensitivities and specificities (79%–100%) for the detection of pulmonary infiltrations and pleural effusions compared to reference CT.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>The diagnostic performance of the assessed 3D-UTE MRI sequences was similar. Both sequences enable the detection of typical inflammatory lung pathologies.</jats:p></jats:sec>