Heroin-induced leukoencephalopathy: characterization using MRI, diffusion-weighted imaging, and MR spectroscopy

Abstract

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