Learning objectives
Describe the imaging findings of central nervous system cryptococcosis;discuss the different findings in immunocompetent and immunocompromised patients and briefly review the literature on the subject.
Background
Cryptococcus neoformans,a saprophytic fungus isolated from soil contaminated with bird excreta,
is particularly pathogenic in immunocompromised patientsand is the third most common pathogen in central nervous system (CNS) infections,
in patients with acquired immunodeficiency syndrome (AIDS),
after infection with human immunodeficiency virus (HIV) andToxoplasma gondii.
The major environmental sources ofC.
neoformansinclude soil contaminated with pigeon excreta and eucalyptus trees/decaying wood.C.
neoformansvar.gattiiis found mainly in tropical and subtropical regions,
whereasC.
neoformansvar.neoformansis encountered worldwide.C.
neoformansvar.neoformansusually infects immunodeficient individuals,
leading to acute diffuse meningitis or meningoencephalitis.
In contrast,...
Findings and procedure details
CNS cryptococcosis produces a wide variety of MRI features that may vary depending on the immunological status of the patient.
The MRI findings range from single to multiple alterations such as hydrocephalus,
leptomeningeal/pachymeningeal enhancement,
dilated perivascular spaces,
miliary nodules,
plexitis (via hematogenous dissemination),
and pseudotumor (cryptococcoma),
occurring in isolation or concomitantly with other MRI findings.
Chronic granulomatous reactions caused byC.
neoformansare more common in immunocompetent hosts than in those with immunosuppression.
On T1-weighted images,
cryptococcal granulomas appear as hypointense lesions,
with or without homogenous enhancement....
Conclusion
Dilatedperivascular spaces and basal ganglia pseudocysts are the most frequently described feature on MRI.
These findings are more common in immunocompromised patients.
Signal characteristics can vary dependant on the form of infection.Meningeal diseasecan showleptomeningeal enhancement.
Cryptococcomas have low signal on T1,
high signal on T2/FLAIR andvariable enhancement,
ranging from no enhancement to peripheral nodular enhancement.Gelatinous pseudocysts tend to give a "soap bubble" appearance.
The havelow to intermediate signal on T1 (from mucin) andhigh signal on T2.
References
Miszkiel KA,
Hall-Craggs MA,
Miller RF,
et al.
The spectrum of MRI findings in CNS cryptococcosis in AIDS.
Clin Radiol.
1996;51:842-50.
Mathews VP,
Alo PL,
Glass JD,
et al.
AIDS-related CNS cryptococcosis: radiologic-pathologic correlation.
AJNR Am J Neuroradiol.
1992;13:1477-86.
SmithAB,Smirniotopoulos JG,Rushing EJ.Central Nervous System Infections Associated with Human Immunodeficiency Virus Infection: Radiologic-Pathologic Correlation.RadioGraphics 2008; 28:2033–2058
DUARTE,
Stenio Bruno Leal et al.Magnetic resonance imaging findings in central nervous system cryptococcosis: comparison between immunocompetent and immunocompromised patients.Radiol Bras[online].
In press.
[cited 2017-12-31].
Available from: <http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-39842017005017101&lng=en&nrm=iso>.
EpubOct26,
2017....