Quantitative susceptibility mapping in patients with systemic lupus erythematosus: detection of abnormalities in normal-appearing basal ganglia

AbstractObjectivesTo evaluate whether quantitative susceptibility mapping (QSM) can be employed to detect abnormalities within normal-appearing basal ganglia on conventional MRI in patients with neuropsychiatric systemic lupus erythematosus (NPSLE).MethodsFor 33 SLE patients (13 NPSLE and 20 non-NPSLE patients) and 23 age/sex-matched controls, two radiologists independently measured the mean QSM and R2* values in various brain structures that appeared to be normal on conventional MR images. These values in each brain structure were compared among the two SLE groups and controls.ResultsRegarding the putamen, the NPSLE patients showed significantly higher QSM values than the non-NPSLE patients and controls (p < 0.05). For the lateral globus pallidus, both SLE groups showed significantly higher QSM values than the controls (p < 0.05). The R2* values were not significantly different between both SLE groups. The NPSLE patients showed a significant correlation between the mean QSM values in putamen and the disease duration (r = 0.63, p < 0.05). For the interobserver agreement, the QSM value was superior to the R2* value (0.690 vs. 0.446, Kendall W value).ConclusionsQSM can be used to identify increased susceptibility of the basal ganglia appearing to be normal on conventional MR images in NPSLE patients.Key Points• QSM values in the putamen are significantly higher in NPSLE than non-NPSLE. • NPSLE patients show correlation between QSM values in the putamen and disease duration. • QSM is more sensitive than R2* mapping for detecting subtle changes.