The diagnostic value of T maps and rs-EPI DWI in dermatomyositis.

OBJECTIVE

: To explore and confirm feasibility the T maps and readout-segmented echoplanar imaging (rs-EPI) diffusion-weighted imaging (DWI) characteristics of the thigh muscles for dermatomyositis (DM) patients.

METHODS

: This study was approved by the University Institutional Review and written informed consent was obtained from all subjects before enrollment (trial registration number: TJ-C20121221). 28 patients with DM proven by diagnostic criteria were enrolled in the study along with 9 healthy control subjects. Conventional MR, T maps and rs-EPI DWI were obtained for all subjects. Both of T and apparent diffusion coefficient (ADC) values for thigh muscles were compared between the DM and healthy control groups. The amount of inflammation and fatty infiltration were respectively assigned a score of 0 to 5 for all thigh muscles. The Kruskal-Wallis tests were utilized and the Spearman correlation coefficients models were used to correlate both of the T and ADC value with non-quantitative MRI. P-values <0.05 reflected statistical significance.

RESULTS

: Both of the T and ADC values among all affected muscles, unaffected muscles and the control groups were respectively statistical difference (p < 0.05 respectively), the T value of affected muscles was greater than that of unaffected muscles in DM patients (p < 0.05). Differences of the T value in DM patients among the combination the edematous with fatty infiltration score groups were statistically significant (p < 0.001). The T value showed a significant correlation with the non-quantitative MRI score for edema and fatty infiltration.

CONCLUSIONS

: T maps may have a specialized ability for the detection severity of damaged muscles in comparison to the rs-EPI DWI sequence.

ADVANCES IN KNOWLEDGE

: A new application of rs-EPI DWI is proposed for DM patients. First, comparison of T maps and rs-EPI DWI technology are applied for DM. The results demonstrate that T maps may be more potential value in determining the severity of diseased muscles for DM patients.