The peak IMP generated by the minimally invasive retractor was significantly less than with the open retractor. Postoperatively, less muscle edema was demonstrated after the minimally invasive lumbar spinal fusion, with lower mean T2 and apparent diffusion coefficient measurements supporting the hypothesis that less damage occurs using a minimally invasive approach.

CT reveals more subchondral fractures in osteonecrosis of the femoral head than unenhanced radiography or MR imaging. The high-signal-intensity line seen on T2-weighted MR images appears to represent fluid accumulating in the subchondral fracture, which may indicate a breach in the overlying articular cartilage.

Purpose: To evaluate three-dimensional driven equilibrium Fourier transform (3D-DEFT) for image quality and detection of articular cartilage lesions in the knee. Materials and Methods:We imaged 104 consecutive patients with knee pain with 3D-DEFT and proton density (PD-FSE) and T2-weighted (T2-FSE) fast spin echo. Twentyfour went on to arthroscopy. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) efficiency were measured. Subjective image quality, fat suppression, and cartilage thickness visibility were assessed. Cartilage lesions on 3D-DEFT and T2-FSE were compared with findings outlined in operative reports.Results: SNR efficiency was higher for 3D-DEFT and PD-FSE than for T2-FSE (P Ͻ 0.02). 3D-DEFT and PD-FSE showed superior cartilage thickness visibility compared with T2-FSE (P Ͻ 0.02). T2-FSE showed better fat suppression and fewer image artifacts than 3D-DEFT (P Ͻ 0.04). 3D-DEFT had similar sensitivity and similar specificity for cartilage lesions compared with PD-FSE and T2-FSE. Conclusion:3D-DEFT provides excellent synovial fluid-tocartilage contrast while preserving signal from cartilage, giving this method a high cartilage SNR. 3D-DEFT shows the full cartilage thickness better than T2-FSE. T2-FSE had superior fat saturation and fewer artifacts than 3D-DEFT. Overall, 3D-DEFT requires further technical development, but is a promising method for imaging articular cartilage.