Bilateral Basal Ganglia Diffusion Restriction on MRI in the Context of Substance Use: A Case Series
Ashraf Alsawareah1, Alan Li2, Mohammad Khasawneh3
1Hashemite University, 2Washington University in St Louis, Department of Neurology, 3Washington University School of Medicine, Neurology Department
Background:
Restricted diffusion on MRI is often associated with acute ischemic stroke, reflecting impaired cellular integrity due to cytotoxic edema. However, similar patterns can occur from toxic or metabolic insults in patients with substance use. This case series presents two patients with bilateral basal ganglia diffusion restriction, emphasizing the importance of distinguishing these findings from ischemic events.
Design/Methods:
Case Presentation:
Case 1: A 66-year-old male with opioid use disorder was found unresponsive with pinpoint pupils and respiratory depression, requiring naloxone and intubation. Brain MRI revealed diffusion restriction with FLAIR hyperintensities in the bilateral globus pallidus and right cerebellum . Urine toxicology was positive for fentanyl, cocaine, amphetamines, and phencyclidine. After treatment for sepsis, rhabdomyolysis, and COPD exacerbation , the patient returned to baseline mental status.
Case 2: A 41-year-old male with Wolff-Parkinson-White syndrome presented with left arm numbness and stroke-like symptoms . Initial MRI revealed punctate diffusion restriction in the internal capsule and bilateral globus pallidus , prompting a differential diagnosis that included ischemia and toxic injury. A urine drug screen, obtained after discharge, was positive for fentanyl and cocaine . His neurological symptoms improved before discharge.
Results:
Discussion:
These cases illustrate that toxic and metabolic injuries can mimic acute stroke on MRI. Basal ganglia are particularly vulnerable to toxic insults due to their high metabolic demand and mitochondrial density . The observed imaging patterns align with previously described cases of CHANTER syndrome , characterized by restricted diffusion in the basal ganglia, hippocampus, and cerebellum due to drug-induced neurotoxicity.
Conclusions:
These cases highlight the importance of recognizing substance-related neurotoxicity to avoid misdiagnosing diffusion restriction as an ischemic event. Accurate identification of toxic patterns will improve management strategies and patient outcomes in substance use-related neurological complications.
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