Correlation between intravoxel incoherent motion MR parameters and MR nodular grade of parotid glands in patients with Sjögren's syndrome: A pilot study.

PURPOSE: To explore the correlation between intravoxel incoherent motion (IVIM) magnetic resonance (MR) parameters and MR nodular grade of parotid glands in patients with Sjögren's syndrome (SS).

MATERIALS AND

METHODS

A total of 31 consecutive patients with SS and 28 gender- and age-matched healthy volunteers underwent bilateral parotid 3.0T MR examination including the IVIM sequence (9 b values, 0-800s/mm2). The apparent diffusion coefficient (ADC), diffusion coefficient D, pseudo-diffusion coefficient D*, and perfusion fraction f of bilateral parotid glands were obtained, and the nodular grade of each parotid gland was evaluated according to the MR morphological appearance.

RESULTS

Sixty-two parotid glands in 31 patients with SS consisted of 32, 14, 8, and 8 parotid glands at MR nodular grades 0, 1, 2, and 3, respectively. In parotid glands of grade 0, 1, 2, 3 and healthy volunteers, the ADC values were (1.13±0.25, 1.11±0.17, 1.05±0.24, 0.89±0.04 and 1.00±0.21)×10-3mm2/s, D values were (0.92±0.13, 0.90±0.19, 0.90±0.03, 0.67±0.03, 0.81±0.03)×10-3mm2/s, f values were 0.20±0.04, 0.18±0.02, 0.15±0.01, 0.11±0.01, 0.15±0.06, and D*values were (53.89±28.26, 41.78±16.35, 51.24±18.69, 31.83±18.03, 36.83±16.14)×10-3mm2/s respectively. The ADC, D, f, and D* values of parotid glands in patients with SS at grade 0 were significantly higher than those in healthy volunteers (all P<0.05). Significant differences were observed in the D and f values of parotid glands in patients with SS among different grades (P=0.003,<0.001, respectively). The IVIM parameters (D, f) of parotid glands at early (grades 0-1) and advanced (grades 2-3) stages in patients with SS were significantly higher and lower, respectively, than those in healthy volunteers (all P<0.05). The D and f values inversely correlated with MR nodular grades significantly (r=- 0.297, P=0.019; r=- 0.653, P<0.001, respectively)

CONCLUSION

The parotid glands with different MR nodular grades in patients with SS showed different IVIM parameters, reflecting different pathophysiological characteristics of parotid glands at different stages.