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Chasing "chasing the dragon" with MRI: leukoencephalopathy in drug abuse

¹ Neuroradiology and ² Department of Medical Imaging, Toronto Western Hospital, University Health Network, 3 Fell Pavilion, Room 210, 399 Bathurst Street, Toronto, Ontario M5T 2S8, Canada

View larger version (46K): [in a new window]   Figure 1. T2 weighted (T2W) images of the brain. (a) Case 1, "chasing" toxicity at initial presentation (above) and at 6-month follow-up (below). Note the increased T2W signal within the cerebellar white matter with some sparing of the dentate nuclei; involvement of the anterior horns (motor) of the brainstem grey matter and the corticospinal tracts; anterior thalami; posterior limb of the internal capsule, with sparing of the anterior limb; splenium of the corpus callosum; posterior corona radiata; and the white matter of the occipital, parietal, posterior temporal and posterior frontal lobes, with sparing of the sub-cortical white matter. (b) Case 2, chasing toxicity at initial presentation, showing similar features to Case 1 to a greater extent, however, and with the addition of abnormal signal in the right globus pallidus. (c) Case 3, no heroin exposure, 11 days after presentation (motion artefact on initial exam). Abnormal increased T2W signal involving the globus palladi and supratentorial white matter with sparing of the sub-cortical white matter. The cerebellum and brainstem are not affected.

View larger version (46K): [in a new window]   Figure 2. Case 1, "chasing" toxicity diffusion weighted imaging/apparent diffusion coefficient (DWI/ADC) images of the brain. (a) Initial presentation, showing no areas of restricted diffusion; no matching areas of increased DWI signal and decreased ADC signal. (b) 6 month follow-up, showing areas of increased water motion corresponding to areas of high T2W signal seen in Figure 1a. The areas of corresponding increased DWI and ADC signal signify areas of increased water diffusion. In such cases, the increased DWI signal is presumably due to "T2 shine-through" effect.

View larger version (25K): [in a new window]   Figure 3. MR spectroscopy at echo time (TE) of 30 m s– and 144 m s–1 with single 20 mm3 voxel placed in the left occipital lobe white matter within regions of increased T2 weighted signal. (a) Case 1, "chasing" toxicity at initial presentation (above) and at 6-month follow-up (below). (b) Case 2, chasing toxicity at initial presentation. (c) Case 3, no heroin exposure, 11 days after presentation.

View larger version (46K): [in a new window]   Figure 4. Graph comparing MR spectroscopy (MRS) ratios between Cases 1–3 to MRS ratios from a set of normal volunteers at our institution.

View larger version (79K): [in a new window]   Figure 5. Case 2, "chasing" toxicity diffusion weighted imaging/apparent diffusion coefficient (DWI/ADC) images of the brain at initial presentation, showing no areas of restricted diffusion. Again noted are the areas of corresponding increased DWI and ADC signal, matching the areas of increased T2 weighted signal. The increased DWI/ADC signal is presumably from the "T2 shine-through" effect.

View larger version (77K): [in a new window]   Figure 6. Case 3, CT at the level of the basal ganglia at initial presentation and at 5-days, showing abnormal low density in the basal ganglia.

View larger version (39K): [in a new window]   Figure 7. Case 3, diffusion weighted imaging/apparent diffusion coefficient (DWI/ADC). (a) Initial presentation showing restricted diffusion in the bilateral white matter; matching areas of increased DWI signal and areas of decreased ADC signal. (b) 11 days later, now showing areas of increased water motion corresponding to the areas of previously seen restricted diffusion; corresponding DWI and ADC areas of increased signal consistent with "T2 shine-through".