Soft-tissue tumors evaluated by line-scan diffusion-weighted imaging: influence of myxoid matrix on the apparent diffusion coefficient.

Purpose To compare the apparent diffusion coefficients (ADCs) of myxoid and nonmyxoid soft-tissue tumors using line-scan diffusion-weighted imaging (LSDWI), and to investigate the myxoid matrix influence on ADCs of soft-tissue tumors. Materials and Methods This study enrolled 44 patients with soft tissue tumors. They were divided into two groups: one with myxoid-containing soft-tissue tumors (N = 23) and the other with nonmyxoid soft-tissue tumors (N = 21). The 44 patients were also classified histologically into 26 with malignant soft-tissue tumors and 18 with benign soft-tissue tumors. LSDWI was performed using b values of 5 and 1000 second/mm2. The ADCs of the tumors were calculated and compared for myxoid and nonmyxoid tumors and for benign and malignant tumors. Results The ADC (mean ± SD) was 1.92 ± 0.41 × 10–3 mm2/second in myxoid containing tumors, whereas the ADC was 0.97 ± 0.33 × 10–3 mm2/second in nonmyxoid tumors. The ADCs of the myxoid and nonmyxoid tumors were significantly different (P < 0.01). The ADCs were 1.45 ± 0.59 × 10–3 mm2/second in malignant tumors and 1.50 ± 0.64 × 10–3 mm2/second in benign tumors. The ADCs of benign and malignant soft-tissue tumors were not significantly different. Conclusion The ADCs of myxoid-containing soft-tissue tumors were significantly higher than those of nonmyxoid soft-tissue tumors. The myxoid matrix influences ADCs of both benign and malignant soft-tissue tumors. J. Magn. Reson. Imaging 2007;25:1199–1204. © 2007 Wiley-Liss, Inc.