Heroin-induced leukoencephalopathy: characterization using MRI, diffusion-weighted imaging, and MR spectroscopy.
OBJECTIVE
To describe the magnetic resonance imaging (MRI) characteristics of heroin-induced leukoencephalopathy or "chasing the dragon syndrome" and, in particular, the diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) features.


METHODS
Six patients with a clinical or histopathological diagnosis of heroin-induced leukoencephalopathy were identified and MRI examinations, including DWI and single-voxel MRS, reviewed.


RESULTS
Cerebellar white matter was involved in all six cases demonstrating similar symmetrical distribution with sparing of the dentate nuclei. Brain stem signal change was evident in five of the six patients imaged. Supratentorial brain parenchymal involvement, as well as brain stem involvement, correlated anatomically with corticospinal tract distribution. None of the areas of signal abnormality were restricted on DWI. Of those patients subjected to MRS, the areas of parenchymal damage demonstrated reduced N-acetylaspartate, reduced choline, and elevated lactate.


CONCLUSIONS
Heroin-induced leukoencephalopathy results in characteristic and highly specific signal abnormalities on MRI, which can greatly aid diagnosis. DWI and MRS findings can be explained by known reported neuropathological descriptions in this condition and can be used to support a proposed mechanism for the benefit of current recommended drug treatment regimes.
Offiah
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Department of Neuroradiology, St Bartholomew's and the London Hospitals NHS Trust, London, UK. curtis.offiah@bartsandthelondon.nhs.uk
Hall
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D000280:Administration, Inhalation; D000328:Adult; D001927:Brain Diseases / Q000139:chemically induced / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006556:Heroin Dependence / Q000150:complications*; D006801:Humans; D019570:Inhalation Exposure; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D020258:Neurotoxicity Syndromes / Q000175:diagnosis* / Q000209:etiology