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The spectrum of MRI findings in CNS cryptococcosis in AIDS
K A Miszkiel1, M A Hall-Craggs, R F Miller
1Imaging Department, UCL Hospital (NHS) Trust, London UK.
Abstract:
We retrospectively reviewed the cranial MRI appearances of 25 patients with AIDS and microbiologically proven central nervous system (CNS) cryptococcosis. Four patients had a normal scan. Ten patients had dilated perivascular Virchow-Robin spaces that were hyperintense on T2-weighted images. Nine of these patients developed progressive cryptococcomas, eight in the basal ganglia and one in the cerebral white matter. The cryptococcomas displayed high signal on T2-weighted and intermediate to low signal on T1-weighted images. None enhanced after dimeglumine gadopentetate. No abnormal dural or leptomeningeal enhancement was detected in any patient. One patient developed an acquired arachnoid cyst during treatment of CNS cryptococcosis which was thought to represent a focal collection of organisms and mucoid material within the subarachnoid space. In addition either cerebral atrophy and/or background white matter hyperintensity on T2-weighted images was present in 19/25 patients. In two patients the neuropathological findings at autopsy correlated well with the imaging abnormalities. In conclusion, this spectrum of MRI appearances in CNS cryptococcosis reflects the pathological mechanism of invasion by the fungus, but a normal scan or one with features of CNS HIV infection such as atrophy or white matter hyperintensity does not exclude the diagnosis.
Insights
Cranial MRI in AIDS patients with CNS cryptococcosis shows varied appearances, including normal scans or HIV-related changes. These findings do not rule out fungal infection, highlighting the need for comprehensive diagnosis.
Area of Science:
- Neurology
- Infectious Diseases
- Radiology
Background:
- Central nervous system (CNS) cryptococcosis is a serious opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS).
- Cranial magnetic resonance imaging (MRI) plays a crucial role in diagnosing CNS infections, but its specific appearances in AIDS-related cryptococcosis require detailed understanding.
Purpose of the Study:
- To retrospectively review and characterize the cranial MRI findings in patients diagnosed with AIDS and central nervous system cryptococcosis.
- To correlate MRI appearances with pathological findings and assess the diagnostic utility of MRI in this patient population.
Main Methods:
- Retrospective review of cranial MRI scans from 25 patients with AIDS and confirmed CNS cryptococcosis.
- Analysis of MRI sequences including T1-weighted, T2-weighted, and post-contrast images.
- Correlation of imaging findings with neuropathological data in autopsy cases.
Main Results:
- Four patients (16%) had normal MRI scans.
- Ten patients (40%) exhibited dilated perivascular spaces hyperintense on T2-weighted images, with nine developing cryptococcomas (lesions in basal ganglia or white matter).
- Cryptococcomas showed high T2 and intermediate-to-low T1 signal intensity without enhancement. Cerebral atrophy or white matter hyperintensity was noted in 19 patients (76%).
Conclusions:
- The spectrum of MRI findings in CNS cryptococcosis reflects fungal invasion mechanisms.
- A normal MRI or findings typical of HIV-related changes (atrophy, white matter hyperintensity) do not exclude the diagnosis of cryptococcosis.
- Comprehensive evaluation considering clinical and microbiological data is essential for accurate diagnosis.