Secondary Signal Change and an Apparent Diffusion Coefficient Decrease of the Substantia Nigra After Striatal Infarction

Abstract

Background and Purpose Diffusion-weighted imaging can depict secondary signal change of the substantia nigra of patients with ipsilateral striatal infarction via a decrease in the apparent diffusion coefficient (ADC). Clinical predictors of this phenomenon remain unclear. Methods We assessed 98 stroke patients with acute ischemic lesions in the hemilateral basal ganglia, external capsule, or internal capsule. The ADC values of the bilateral substantia nigra obtained from a follow-up MRI, various clinical factors, and patients’ outcome were analyzed. Nineteen patients who underwent a follow-up MRI within 3 days were excluded from analysis because none of them demonstrated a significant ADC change of substantia nigra. Results Of 79 patients, 21 (26.6%) revealed a decreased ADC in the substantia nigra. Ischemic lesions in the globus pallidus (odds ratio 12.90) and the presence of emboligenic diseases (odds ratio 6.95) were independent predictors for an ADC decrease in the substantia nigra. The clinical outcome 3 months after stroke onset was not different between patients with an ADC decrease and patients without. Conclusions A reduction of ADC in the substantia nigra after acute striatal infarction was more frequently observed when the globus pallidus was affected or when the patient had emboligenic diseases, however, did not necessarily relate to the patient's clinical outcome.

Neurodegeneration of the Substantia Nigra after Ipsilateral Infarct: MRI R2* Mapping and Relationship to Clinical Outcome

“…We measured ADC within the SN under the same masks as those used for R2* measurements. SN-AI 5 of ADC was lower in participants from the striatum group than in participants from the control group at the baseline MRI (P , .002), but no more at the 1-year MRI, indicating transient focal areas of low ADC values within SN when the striatum is infarcted (Table E3 [online]) in line with previous reports (11,12). However, we only found a weak correlation between SN-AI 5 of ADC at baseline and SN-AI 95 of R2* at follow-up (r = 20.18 [95% CI: 20.32, 20.04] in the total population) suggesting that R2* at follow-up provided information that was only weakly captured with early ADC.…”

“…coefficient (ADC) (11,12) have been widely reported within SN as early as 4-6 days following ipsilateral infarcts, and especially when the striatum is involved. MRI-to-histologic correlations suggest that T2 and ADC changes may reflect astrocytic swelling (13,14).…”

Dynamic secondary degeneration in the spinal cord and ventral root after a focal cerebral infarction among hypertensive rats

“…Focal cerebral infarctions can induce trans-synaptic degeneration in nonischemic, remote brain areas, such as the thalamus, hippocampus, and substantia nigra, which have synaptic connections with primary ischemic sites 1 2 3 . Such secondary degeneration has been demonstrated with neuroimaging techniques and pathological examinations across both clinical studies and animal experiments 4 .…”

Secondary pallidonigral degeneration mimicking recurrent acute stroke in clinical presentation and magnetic resonance imaging: a case report

“…This type of insult has been attributed to excessive excitation of the postsynaptic deep nuclei due to the loss of trans-synaptic γ-aminobutyric acid (GABA-)ergic inputs, which mediate the striatonigral pathway [ 6 , 7 ]. In our patient, the observed cytotoxic edema in the pallidum and SN, as shown in DWI, were likely due to axonal intramyelinic swelling or astrocytic swelling [ 8 , 9 ], a result of disinhibition of the striatonigral GABAergic pathway. The local increase in fluid accumulation within the inter-myelinic layers could also be the underlying cause of MR signal changes on FLAIR/T2WI at acute setting.…”