Evaluation of the Swallow-Tail Sign and Correlations of Neuromelanin Signal with Susceptibility and Relaxations

Abstract

The presence of a swallow-tail sign in the nigrosome-1 with hyperintense signal shown on the susceptibility-weighted imaging (SWI) has been shown to be sensitive in detecting the abnormal iron deposits in this area. A systematic evaluation in healthy subjects is required before this tool can be recommended in a widespread application. We evaluated a simple and practical SWI approach using a multiecho gradient-echo sequence with an improved contrast-to-noise ratio (CNR). We also evaluated the association of the neuromelanin imaging contrast behavior with the susceptibility and relaxation measurements. Twenty-five older and 23 young healthy adults were evaluated. The CNRs of the nigrosome-1 were compared along with method and group. Correlations of the nigrosome-1 neuromelanin signal in the neuromelanin-sensitive imaging with CNRs in the susceptibility, T1 and T2 mappings were examined. Two different coils were used to confirm the reproducibility. Compared with the single-echo, multiecho SWI can improve the CNR of the swallow-tail sign. We found significant correlations between neuromelanin signal and CNRs in the susceptibility and T2 mappings, and T1 value. The older subjects exhibited increased CNRs compared with the young adults. No significant difference was observed in the measurements between 20 and 64 channels. The multiecho technique allows the high-quality nigrosome-1 images in SWI and allows for a joint analysis of T2* and quantitative-susceptibility mapping at high spatial resolution. The correlations of neuromelanin-sensitive imaging with susceptibility and T2 imply that the iron content in the nigrosome-1 may have significant influences on the hyperintensity of neuromelanin in the magnetization transfer-related contrast.

Diagnostic value of combined magnetic resonance imaging techniques in the evaluation of Parkinson disease

“…In this study, the rate of disappearance of the swallow tail sign was significantly higher in the PD group than in the healthy control group. However, the disappearance of the swallow tail sign was not correlated with the disease course duration or H-Y grade, which is inconsistent with the previous studies ( 17 - 19 ). The lack of correlation in our study may be attributable to the relatively long disease course of the patients in the PD group and the limited number of cases.…”

Modified Iron Deposition in Nigrosomes by Pharmacotherapy for the Management of Parkinson’s Disease

“…In our study, all PD patients had different degrees of nigrosome volume loss compared with healthy people. Although some studies have suggested that the nigrosome had the typical “swallow tail” appearance ( Lee et al, 2021 ), a greater volume of the nigrosome was observed in the SNc by using SWI with different susceptibilities. Moreover, SWI measures iron accumulation with a semiquantitative pattern and can be used to track iron accumulation in PD ( Weinreb et al, 2013 ; Takahashi et al, 2018 ).…”