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

Yoon, Sam Hyun; Ha, Doo Hoe

Abstract

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.