J Korean Soc Radiol.  2010 Nov;63(5):403-407. 10.3348/jksr.2010.63.5.403.

Progressive Multifocal Leucoencephalopathy Isolated to Posterior Fossa in a Patient with AIDS: DWI and 1H-MRS Features

• Park BS
• Yu IK
• Lee BH

• KMID: 2097908
• DOI: http://doi.org/10.3348/jksr.2010.63.5.403

Abstract

We report a case of progressive multifocal leukoencephalopathy (PML) isolated to the posterior fossa in a 55-year-old male with acquired immune deficiency syndrome(AIDS). Initial MR images revealed a few foci of patchy increased signal intensity(SI)on a T2-weighted image and a diffusion weighted image (DWI) at the pons, right middle cerebellar peduncle, and right cerebellar hemisphere, with no enhancement. After anti-retroviral therapy, follow-up MR images revealed the more prominent extent of previously-seen lesions and newly discovered newly developed focal increased SI on T2-weighted images located left of the inferior cerebellar hemisphere. Proton MR spectroscopy (1H-MRS) showed a slightly increased choline peak (3.2 ppm) and lactate peak (1.35 ppm), as well as a decreased N-acetylaspartate (NAA) peak (2.0 ppm), which suggests active demyelinating disease. DWI and 1H-MRS may support the diagnosis of PML in patients with AIDS.

MeSH Terms

Aspartic Acid
Cerebellum
Choline
Demyelinating Diseases
Diffusion
Follow-Up Studies
Humans
Lactic Acid
Leukoencephalopathy, Progressive Multifocal
Magnetic Resonance Imaging
Magnetic Resonance Spectroscopy
Male
Middle Aged
Pons
Protons
Aspartic Acid
Choline
Lactic Acid
Protons

Figure

• 

  Fig. 1 Initial MRI (A: T2-weighted image (WI), B: T1-WI, C: contrast enhanced T1-WI) revealed a few foci with patchy increased signal intensity (SI) on T2-WI and decreased SI on T1-WI at the pons, right middle cerebellar peduncle, and right cerebellar hemisphere with no enhancement.

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  Fig. 2 DWI (A) and ADC map (B) showed high signal intensity (SI) on DWI and normal-to-low SI on an ADC map at the peripheral margin of right cerebellar hemisphere, while low SI on DWI and high SI on an ADC map at the center. We suggest that these characteristic features of DWI and the ADC map could be called a "layered phenomenon".

• 

  Fig. 3 MR spectroscopy showed a slightly increased choline peak (3.2 ppm) and lactate peak (1.35 ppm), as well as a decreased N-acetylaspartate (NAA) peak (2.0 ppm), suggesting demyelinating disease.

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  Fig. 4 Twenty-two day follow-up MRI (A: T2-weighted image (WI), B: T1-WI, C: contrast enhanced T1-WI) showed a slight extension of the previous lesions at the pons, right middle cerebellar peduncle, and right cerebellar hemisphere with newly developed (not seen) focal high SI on T2-WI at the left inferior cerebellar hemisphere.

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