Magnetic resonance imaging of the lung with a volumetric interpolated 3D-gradient echo sequence

To evaluate the feasibility of a magnetic resonance imaging protocol for the lung using a volumetric interpolated 3D-gradient echo sequence (3D-GRE).

A T(1)-weighted 3D-GRE sequence was used for volumetric interpolated breath-hold examinations ("VIBE") of the lung in twelve healthy volunteers (TR/TE 4.5/1.9 ms, flip-angle 12 degrees, matrix 502 X 512 [interpolated]). Three coronal 80 mm slabs (16 aportitions, 2.5 mm slices) were added to 3D data sets for multi-planar reformations. No contrast material was applied. Artifacts and resolution o vessel and airway structures in each lung segment were evaluated by two observers (12 volunteers, 228 lung segments).

The protocol provided excellent images of vascular and tracheo-bronchial structures with very moderate pulsation artifacts. 224/228 lung segments were imaged with "good" (146/228) or "sufficient" quality (78/228). Segmental and sub-segmental vessels (5th order) were identified due to bright flow signal without administration of contrast material. Walls of segmental bronchi (3rd order) were delineated in all parts of the lung.

The high spatial resolution, the excellent visualization of lung anatomy, the low rate of artifacts without respiratory triggering and the short acquisition times are clear advantages of the 3D-GRE (VI-BE) sequence compared to existing 2D-GRE strategies for MRI of the lung.