Noninvasive MR cisternography with fluid-attenuated inversion recovery and 100% supplemental O(2) in the evaluation of neurocysticercosis

Abstract

We describe an MR protocol for the noninvasive imaging of the subarachnoid space, which we use in patients with suspected neurocysticercosis in this space. It consists of a fluid-attenuated inversion recovery sequence performed 5 minutes after the continuous inhalation of 100% O(2) with a resultant increase in the signal intensity of the CSF that leads to a greater conspicuity of cyst walls in relation to the cortex and the extraventricular CSF.

Fig 1.

A 40-year-old man with parenchymal neurocysticercosis and suspected subarachnoid involvement. A, MR FLAIR image (1.0 T; TR, 11,000 ms; TE, 140 ms; TI, 2600 ms) shows no extraaxial lesions. B, FLAIR image after 100% O₂ for 5 minutes shows two small cysts in the Sylvian fissures confirming racemous neurocysticercosis.

Fig 2.

A 57-year-old man with multiple vesicular lesions in the brain parenchyma. A, FLAIR image shows prominent CSF space along the cerebral convexities. B, FLAIR image after 100% O₂ for 5 minutes does not show the expected increased signal intensity of the CSF due to the presence of multiple clustered extraaxial cysts. The walls of the cysts (arrows) are better visualized after 100% O₂.

Fig 3.

A 34-year-old male patient with known neurocysticercosis. A, B, and C, FLAIR images show multiple vesicular lesions in the parenchyma, mainly along the cortical surfaces. The perimesencephalic cisterns are prominent and contain hyperintense foci that could represent the expected flow artifact or cystic lesions with scoleces (B). D, E, and F, FLAIR after 100% O₂ shows increased signal intensity in the sulci and basal cisterns, allowing the visualization of a greater number of cortical lesions in the frontal, temporal, and occipital lobes. Also, the increased signal intensity of the CSF confirms that there is no cystic lesion in the perimesencephalic cisterns (E).