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Progressive multifocal leukoencephalopathy and human immunodeficiency virus-associated white matter lesions in AIDS:

T Ernst1, L Chang, M Witt

  • 1Department of Radiology, Harbor-UCLA Medical Center, Torrance 90502, USA.

Radiology
|April 20, 1999
PubMed
Abstract

Insights

Magnetization transfer MRI can differentiate progressive multifocal leukoencephalopathy (PML) from HIV-associated white matter lesions in AIDS patients. PML lesions show a significantly lower magnetization transfer ratio, indicating demyelination, compared to HIV-WML, which suggest gliosis.

Area of Science:

  • Neuroimaging
  • Radiology
  • Infectious Diseases

Background:

  • Acquired immunodeficiency syndrome (AIDS) patients often develop white matter lesions (WML).
  • Differentiating progressive multifocal leukoencephalopathy (PML) from human immunodeficiency virus (HIV)-associated WML is clinically important.
  • Conventional MRI may not reliably distinguish between these lesion types.

Purpose of the Study:

  • To investigate the utility of magnetization transfer (MT) magnetic resonance (MR) imaging in characterizing PML and HIV-WML in AIDS patients.
  • To determine if MT parameters can differentiate between PML and HIV-WML.

Main Methods:

  • Conventional and MT MR imaging were performed on 21 AIDS patients with 42 white matter hyperintensities.
  • Magnetization transfer ratio (MTR) was calculated for each lesion and compared to normal-appearing white matter.
  • Lesion size was considered for diagnostic validity.

Main Results:

  • Both PML and HIV-WML demonstrated reduced MTR compared to normal white matter.
  • PML lesions exhibited significantly lower MTR (26.1%) than HIV-WML (38.0%), with no overlap.
  • This MTR differentiation was effective for lesions as small as 0.5 cm².

Conclusions:

  • The pronounced MTR reduction in PML lesions suggests demyelination, while the lesser reduction in HIV-WML is likely due to gliosis.
  • MT MR imaging is a valuable noninvasive tool for distinguishing PML from HIV-WML in AIDS patients.
  • PML lesions cause substantial MTR reductions early in disease progression.

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