MR knee imaging: axial 3DFT GRASS pulse sequence versus spin-echo imaging for detecting meniscal tears

Area of Science:

• Radiology
• Orthopedic Imaging
• Medical Diagnostics

Background:

• Knee pain evaluation often requires accurate detection of meniscal tears.
• Magnetic Resonance (MR) imaging is a key tool for diagnosing knee pathologies.
• Comparing advanced MRI sequences to standard techniques is crucial for diagnostic improvement.

Purpose of the Study:

• To assess the sensitivity and specificity of thin axial 3D Fourier transform (3DFT) gradient-recalled acquisition in the steady state (GRASS) MR imaging for detecting meniscal tears.
• To compare the diagnostic performance of 3DFT GRASS sequences with conventional spin-echo sequences.
• To evaluate the utility of 3DFT GRASS in identifying specific types of meniscal tears and fragments.

Main Methods:

• Retrospective analysis of MR imaging in 17 patients (34 menisci) with knee pain.
• Acquisition of thin axial 3DFT GRASS images through the menisci.
• Comparison of 3DFT GRASS findings with spin-echo images (coronal and sagittal planes).
• Correlation of imaging results with arthroscopy findings as the gold standard.

Main Results:

• Arthroscopy identified 12 meniscal tears.
• Axial 3DFT GRASS detected 10 of 12 tears (83%), while spin-echo detected 9 of 12 (75%).
• 3DFT GRASS showed one false-positive tear, compared to two with spin-echo.
• 3DFT GRASS was particularly useful for peripheral, displaced, and complex meniscal tears.

Conclusions:

• Thin axial 3DFT GRASS MR imaging is comparable to spin-echo techniques for meniscal tear detection.
• 3DFT GRASS provides valuable complementary information, especially in complex meniscal injuries.
• This advanced technique aids in visualizing peripheral tears and displaced fragments, enhancing diagnostic accuracy.