Comparison of radial versus cartesian k-space sampling in T1-weighted MRI: image quality assessment for contrast-enhanced thoracic spine transverse imaging

Motion artifacts caused by respiration, cardiac pulsation, and vascular flow often degrade image quality in conventional contrast-enhanced transverse T1-weighted magnetic resonance imaging (MRI) of the thoracic spine, hindering lesion detection and characterization. Although radial k-space sampling sequences have demonstrated strong motion artifact suppression through non-Cartesian acquisition trajectories, their clinical value in contrast-enhanced thoracic spine MRI remains unverified. This study aimed to evaluate the clinical utility of the free-breathing radial k-space sampling sequence for contrast-enhanced transverse T1-weighted MRI of thoracic spine. Total of 48 patients with thoracic vertebral lesions enrolled in this prospectively study underwent contrast-enhanced thoracic spine examination on a 3T MRI scanner from July 2024 to March 2025. After contrast administration, three transverse sequences, including conventional two-dimensional T1-weighted imaging with modified Dixon turbo spin echo (2D T1WI-mDixon-TSE), breath-hold three-dimensional T1-weighted imaging with modified Dixon gradient echo (3D T1WI-mDixon-GRE), and free-breathing 3D volumetric accelerated navigator echo with extended dynamic range (3D VANE XD) were acquired. Signal-to-noise ratio (SNR) was measured at the central slice. Two radiologists independently scored artifact suppression, thoracic vertebra/lesion clarity and overall image quality using a 4-point Likert scale. The differences in SNR and subjective evaluation scores among above three sequences were compared and analyzed. The free-breathing 3D VANE XD and 3D T1WI-mDixon-GRE sequences achieved significantly higher SNR than 2D T1WI-mDixon-TSE sequence (both p < 0.01). In the subjective evaluation of artifact suppression, the free-breathing 3D VANE XD sequence also scored highest [3.90(3.81, 3.95)], followed by the breath-hold 3D T1WI-mDixon-GRE [3.55(3.50, 3.70)] and 2D T1WI-mDixon-TSE sequences [2.90(2.75, 3.08)]. For the clarity of thoracic vertebra and lesion, the free-breathing 3D VANE XD sequence scored significantly highest (both p < 0.01). And the overall image quality of free-breathing 3D VANE XD sequence was significantly best [3.90 (3.85, 3.95)] than the other two sequences (both p < 0.01). The free-breathing 3D VANE XD sequence significantly improved the image quality of contrast-enhanced transverse T1-weighted MRI for thoracic spine, supporting its integration into routine clinical practice.