Use of intravoxel incoherent motion diffusion-weighted imaging in identifying the vascular and avascular zones of human meniscus.

PURPOSE: To investigate the hypothesis that the intravoxel incoherent motion (IVIM) diffusion-weighted imaging may depict microcirculation of meniscus and the perfusion changes in meniscal disorder.

MATERIALS AND METHODS: Fifty patients received diffusion-weighted MRI with multiple b-values ranging from 0 to 400 s/mm2 . The four horns of the menisci were divided into normal, degenerated, and torn groups. IVIM parameters including perfusion fraction (f), pseudo-diffusion coefficient (D*), true diffusion coefficient (D), and the product of f and D* (f D*) of normal meniscal red zone and white zone were derived and compared for microcirculation changes of normal, degenerated, and torn posterior horn of the medial meniscus (PMM). The parameters between red and white zones among the groups were compared. Significant differences were considered when P < 0.05.

RESULTS: Mean f and fD* were significantly higher in the red zone than those in the white zone for the normal four meniscal horns (P < 0.05), whereas D* (P = 0.882, 0.011, 0.593, and 0.33) and D (P = 0.186, 0.099, 0.767, and 0.041) did not significantly differ between the two zones. Among the normal, degenerated, and torn PMM, f was observed to be lower in the red zone of torn horns as compared to the normal horns (P = 0.013). D*, fD*, and D did not exhibit statistically significant difference among different groups (P = 0.353, 0.661, and 0.327, respectively).

CONCLUSION: This hypothesis driven work shows that IVIM imaging is able to depict microcirculation of meniscus and the perfusion changes in meniscal disorder.

LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:1090-1096.