Usefulness of Dual-Echo in Steady State(DESS) Image in Chondromalacia of Knee Joint: Comparison of DESS and Turbo Spin-Echo MR Images

PURPOSE: To evaluate the usefulness of Dual Echo in State(DESS) image in the diagnosis of chondromalacia of the knee compared with turbo spin-echo MR images. MATERIALS AND METHODS: We included 26 patients with chondromalacia of the knee. MR imaging was obtained with a 1.5T imager. Sagittal and coronal double echo T2 weighted images(TR/TE 3000~4200/16-96msec, FOV 140-160140-160mm, matrix size 180256, slice thickness 4.0mm, interslice gap 0.5mm), and sagittal DESS image(TR/TE 25.4/9.0msec, flip angle 35-45, FOV 150-160150-160mm, matrix size 192256, effective slice thickness 1.5mm) were obtained. Cartilage lesions were staged according to a modified scheme proposed by Outerbridge: grade 0, normal; grade 1, softening or/and we swelling; grade 2, mild surface fibrillation or/and less than 50% of cartilage thickness; grade 3, severe surface fibrillation or/and loss of more than 50% of cartilage thickness but without exposure of subchondral bone; and grade 4, complete loss of cartilage with subchondral bone exposure. Gradings were determined by two readers with consensus, and patellofemoral, medial and lateral tibiofemoral compartments were evaluated. RESULTS: Arthroscopic findings revealed grade 1 in seven cases, grade 2 in 21 cases, grade 3 in six cases, and grade 4 in 18 cases. Sensitivity of turbo spin-echo MR images was as follows: 0%, 14%, 0%, 61% in each grade, and sensitivity of DESS image was as follows; 0%, 33%, 50%, 67% in each grade(p=0.001). In the detection of chondromalacic lesions regardless of gradings, sensitivity, specificity and accuracy of conventional MR image were 59.6%, 88.6%, 78.8% and of DESS image,73.1%, 88.4%, 82.2%(p=0.007). CONCLUSION: For chondromalacia of knee joints, DESS images showed higher sensitivity than turbo spinehco MR images. Therefore, DESS images will be helpful for diagnosis of chondromalacia of knee joints.

Diagnosis of Meniscal Tear of the Knee Using Proton-weighted Fast Spin-Echo MR Imaging: Can be an Alternative to Conventional Spin-Echo Imaging?

PURPOSE: The purpose of this study was to evaluate the sensitivity and specificity of proton-weighted fast spin-echo MR imaging in diagnosing the meniscal tear of knee as an reasonable substitute for conventional spin-echo imaging. MATERIALS AND METHODS: 102 consecutive patients, proved by surgery, were participated in this study. All of them were suspected internal derangement of knee, examined by fast spin-echo MR imaging including sagittal and coronal images on a 1.5T MR imager and underwent arthroscopic or open surgery of knee joint within 2 months. These images were reviewed retrospectively by three radiologists. The sensitivity and specificity of meniscal tear were calculated. RESULTS: The sensitivity and specificity of meniscal tear reviewed by proton-weighted fast spin-echo MR imaging were 94%, 93% in medial meniscus and 92%, 88% in lateral meniscus. CONCLUSION: The sensitivity and specificity of meniscal tear using proton weighted fast-spin echo MR images were as high as those using conventional spin-echo MR imaging in diagnosing meniscal tear of the knee.