Knee derangements: comparison of isotropic 3D fast spin-echo, isotropic 3D balanced fast field-echo, and conventional 2D fast spin-echo MR imaging

To compare diagnostic performance, subjective image quality, and artifacts of isotropic three-dimensional (3D) intermediate-weighted (IW) fast spin-echo (SE), isotropic 3D balanced fast field-echo (FFE), and conventional two-dimensional (2D) fast SE 3.0-T MR sequences in evaluation of cartilage, ligaments, menisci, and osseous knee structures in symptomatic patients. Institutional review board approval and waiver of informed consent were obtained for this HIPAA-compliant study. One hundred MR studies, each with three data sets (3D IW fast SE, 3D balanced FFE, 2D fast SE), were reviewed retrospectively. Two radiologists independently evaluated images for cartilaginous defects, anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial meniscus (MM), lateral meniscus (LM) tears, subchondral bone marrow signal abnormalities, subjective image quality, and image artifacts. Arthroscopic results were the reference standard. Statistical analysis was performed to calculate interobserver agreement and compare diagnostic performance of sequences. Sensitivity and specificity were greater than 85% for all lesions. For cartilaginous defects, sensitivity of 3D IW fast SE was significantly greater than that of 3D balanced FFE (95.5% vs 89.7%). Sensitivity of 3D IW fast SE and 2D fast SE for MM, LM, and ACL tears tended to be greater than that of 3D balanced FFE. IW fast SE had a higher detection rate for subchondral bone marrow signal abnormality than did 3D balanced FFE (34% vs 21%); it also had the best image quality and fewest artifacts, followed by 2D fast SE and 3D balanced FFE. Interobserver agreement was excellent for evaluation of all intraarticular structures (κ = 0.85-1) and good to excellent for detection of subchondral bone marrow signal abnormality (κ = 0.76-0.91). The performance of IW fast SE is superior to that of balanced FFE in evaluation of cartilaginous defects, with no significant difference in performance between 2D fast SE, 3D IW fast SE, and 3D balanced FFE in evaluation of meniscal and ligament tears. Subchondral bone marrow signal abnormality is more easily seen on 3D IW fast SE images, with better subjective image quality and fewer artifacts, than on images obtained with other techniques.