Diagnosis of Early-Stage Idiopathic Parkinson's Disease Using High-Resolution Quantitative Susceptibility Mapping Combined with Histogram Analysis in the Substantia Nigra at 3 T

A 66-year-old man with underlying hypertension and dyslipidemia presented with left hand tremor for one year. He also noticed difficulty in initiating movement and slowness in activities of daily living. On examination, he was noted to have mask-like facies with reduced blinking and monotonous speech. There was presence of resting pill-rolling tremor, bradykinesia, and cogwheel rigidity which was worst on the left upper limb. Gait assessment revealed difficulty in standing up, shuffling gait with reduced arm swing which was more prominent on the left side, and turning in numbers. No cerebellar signs and supranuclear palsy were present to suggest Parkinson-plus syndrome. Susceptibility weighted imaging (SWI) showed loss of the swallow tail sign on the right side [Figure 1]. The clinical presentation, supplemented by the imaging findings were concluded to be pathognomonic of idiopathic Parkinson’s disease (IPD), Hoehn & Yahr stage 1. He was started on levodopa and benserazide twice daily with improvement of symptoms.The nigrosomes are primary subregions of the substantia nigra where dopaminergic cells are lost in IPD. Within these nigrosomes, maximal cell loss occurs in nigrosome-1; the largest subgroup of nigrosomes. Normally, they appear as a SWI-hyperintense area surrounded by hypointensity within the dorsolateral substantia nigra, akin to a swallow’s tail. In one study, poor visualization of nigrosome-1 was significantly associated with higher motor asymmetry in the contralateral side (sensitivity 98.5%, specificity 93.6%, positive-predictive value 98.3%, negative-predictive value 98.3% and an accuracy of 96%) [1]. Noh et al [2] showed that abnormality involving nigrosome-1 can be detected at 3T MR imaging with an accuracy of 94.6%. Due to the difficulty in diagnosis of early stage IPD, a loss of the swallow tail sign serves as a useful imaging biomarker to supplement the clinical diagnosis, as seen in our patient.

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High-resolution ultrasound changes of the vagus nerve in idiopathic Parkinson’s disease (IPD): a possible additional index of disease

Neurological Sciences ◽

10.1007/s10072-021-05183-5 ◽

2021 ◽

Author(s):

F. Sartucci ◽

T. Bocci ◽

M. Santin ◽

P. Bongioanni ◽

G. Orlandi

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

High Resolution ◽

Vagus Nerve ◽

Imaging Modality ◽

Disease Stage ◽

Motor Nucleus ◽

Idiopathic Parkinson’S Disease ◽

Idiopathic Parkinson's Disease ◽

Additional Index

Abstract Background and rationale Histopathological studies revealed degeneration of the dorsal motor nucleus of the vagus nerve (VN) early in the course of idiopathic Parkinson’s disease (IPD). Degeneration of VN axons should be detectable by high-resolution ultrasound (HRUS) as a thinning of the nerve trunk. In order to establish if the VN exhibits sonographic signs of atrophy in IPD, we examined patients with IPD compared with age-matched controls. Material and methods We measured the caliber (cross-sectional area, CSA) and perimeter of the VN in 20 outpatients with IPD (8 females and 12 males; mean age 73.0 + 8.6 years) and in age-matched controls using HRUS. Evaluation was performed by blinded raters using an Esaote MyLab Gamma device in conventional B-Mode with an 8–19 MHz probe. Results In both sides, the VN CSA was significantly smaller in IPD outpatients than in controls (right 2.37 + 0.91, left 1.87 + 1.35 mm2 versus 6.0 + 1.33, 5.6 + 1.26 mm2; p <0.001), as well as the perimeter (right 5.06 + 0.85, left 4.78 + 1.74 mm versus 8.87 + 0.86, 8.58 + 0.97 mm; p <0.001). There were no significant correlations between VN CSA and age, the Hoehn and Yahr scale, L-dopa therapy, and disease duration. Conclusion Our findings provide evidence of atrophy of the VNs in IPD patients by HRUS. Moreover, HRUS of the VN represent a non-invasive easy imaging modality of screening in IPD patients independent of disease stage and duration and an interesting possible additional index of disease.

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