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Convincing evidence for magic angle less‐sensitive quantitative T1ρ imaging of articular cartilage using the 3D ultrashort echo time cones adiabatic T1ρ (3D UTE cones‐AdiabT1ρ) sequence

Year: 2020

Type: article

Abstract: Purpose To investigate the magic angle effect in three‐dimensional ultrashort echo time Cones Adiabatic T1ρ (3D UTE Cones‐AdiabT1ρ) imaging of articular cartilage at 3T. Methods The magic angle effect was investigated by repeated 3D UTE Cones‐AdiabT1ρ imaging of eight human patellar samples at five angular orientations ranging from 0° to 90° relative to the B0 field. Cones continuous wave T1ρ (Cones‐CW‐T1ρ) and Cones‐ sequences were also applied for comparison. Cones‐AdiabT1ρ, Cones‐CW‐T1ρ and Cones‐ values were measured for four regions of interest (ROIs) (10% superficial layer, 60% transitional layer, 30% radial layer, and a global ROI) for each sample at each orientation to evaluate their angular dependence. Results 3D UTE Cones‐AdiabT1ρ values increased from the radial layer to the superficial layer for all angular orientations. The superficial layer showed the least angular dependence (around 4.4%), while the radial layer showed the strongest angular dependence (around 34.4%). Cones‐AdiabT1ρ values showed much reduced magic angle effect compared to Cones‐CW‐T1ρ and Cones‐ values for all four ROIs. On average over eight patellae, Cones‐AdiabT1ρ values increased by 27.2% (4.4% for superficial, 23.8% for transitional, and 34.4% for radial layers), Cones‐CW‐T1ρ values increased by 76.9% (11.3% for superficial, 59.1% for transitional, and 117.8% for radial layers), and Cones‐ values increased by 237.5% (87.9% for superficial, 262.9% for transitional, and 327.3% for radial layers) near the magic angle. Conclusions The 3D UTE Cones‐AdiabT1ρ sequence is less sensitive to the magic angle effect in the evaluation of articular cartilage compared to Cones‐ and Cones‐CW‐T1ρ.

Source: Magnetic Resonance in Medicine

DOI: 10.1002/mrm.28317