Mri-guided musculoskeletal needle biopsy by using ultrashort echo time sequence.

OBJECTIVES: To improve the susceptibility artifacts, efficiency and safety during MRI-guided musculoskeletal needle biopsy by using ultrashort echo time (UTE) sequence. METHODS: A dedicated UTE sequence was developed and implemented on a 3.0-T PET/MR system.In an ex vivo bovine thigh model, a biopsy needle was inserted at three angles relative to the B0 field direction.UTE was compared with conventional sequences, including 2DT1WI, 3DT1WI, and balanced steady-state free precession(bSSFP). Artifact dimensions parallel and perpendicular to the needle were independently measured by two radiologists, and mean values were analyzed.Subsequently, patients with suspected musculoskeletaltumors underwent MRI-guided needle biopsies using the optimized UTE. Two radiologists independently evaluated image quality and needle conspicuity using a 5-point Likert scale.Differenceswere analyzed using the Friedman test with post hoc Wilcoxon signed-rank tests and Bonferroni correction.Interobserver agreement was calculated using intraclass correlation coefficients. RESULTS: The UTE sequence was optimized with aminimum TE of 0.11 ms, isotropic 1.5-mm voxels (reconstructed to 0.75 mm), and a 22.8-s acquisition time. Compared with conventional sequences, UTE produced smaller artifacts in the phantom model,with up to 70% reduction at the 90° insertion angle relative to B0.Artifact morphology remained stable across angles and planesinUTE sequences. Clinically, UTE provided adequate lesion conspicuity (3.50 ± 0.40) and excellentneedle visibility (4.39 ± 0.45) , with good-to-excellent interobserver agreement. CONCLUSIONS: Optimized UTE significantly reduces needle-related susceptibility artifacts and improves lesion and needle visualization during MRI-guided musculoskeletalbiopsy.