Radiological manifestations of cryptococcal infection in central nervous system

Background. Cryptococcus neoformans is one of the most common infectious agents causing central nervous system (CNS) infections in immunocompromised patients. Patients with CNS cryptococcosis commonly present with non-specific manifestations such as headache, fever, seizure and conscious disturbance. This article presents the computerized tomography scans (CT) and magnetic resonance images (MRI) findings of cryptococcal infection in CNS and displays the image difference between immunocompromised and non-immunocompromised patients. Methods. CNS cryptococcal infection was found in 26 cases over the past 14 years in Taipei Veterans General Hospital, including 18 males and 8 females. Ten patients were immunocompromised. In all cases, the CNS cryptococcosis was diagnosed by positive cryptococcal antigen titer and India ink stain from cerebral spinal fluid (CSF). Their clinical data and findings from CT and MRI were retrospectively studied. Results. The most common CT manifestation is ventricular dilatation; other common findings include leptomeningeal enhancement, infarction (half of them revealed dilatation of Virchow-Robin spaces in subsequent MRI study) and normal appearance. Less common findings are ventriculitis and abscess formation. The most common MRI pattern is Virchow-Robin space dilatation and leptomeningeal enhancement. Other common appearance includes ventricular dilatation. Less common manifestations include cryptococcoma, hemorrhagic infarction and pontine abscess. There is no significant difference in image patterns between immunocompromised and non-immunocompromised patients (p > 0.05). Conclusions. The most common pattern of CNS cryptococcosis is ventricular dilatation in CT and Virchow-Robin space dilatation in MRI. MRI is more sensitive in detecting CNS cryptococcal infection like Virchow-Robin space dilatation and leptomeningeal enhancement. There is no significant pattern difference between immunocompromised and non-immunocompromised patients with CNS cryptococcosis.