Relevance of 3D magnetic resonance imaging sequences in diagnosing basal subarachnoid neurocysticercosis

Abstract

Imagenological diagnosis of subarachnoid neurocysticercosis is usually difficult when classical magnetic resonance imaging (MRI) sequences are used. The purpose of this study was to evaluate the advantages of 3D MRI sequences (Fast Imaging Employing Steady-state Acquisition (FIESTA) and Spoiled Gradient Recalled Echo (SPGR)) with respect to classical sequences (Fluid Attenuation Inversion Recovery (FLAIR) and T1) in visualizing Taenia solium cyst in these locations. Forty-seven T. solium cysts located in the basal cisterns of the subarachnoid space were diagnosed in eighteen Mexican patients. A pre-treatment MRI was performed on all patients, and all four sequences (FIESTA, FLAIR, T1 SPGR, and T2) were evaluated independently by two neuroradiologists. The sensitivity of each sequence to detect the parasite membrane and scolex was evaluated, along with its capacity to detect differences in signal intensity between cerebrospinal fluid (CSF) and cysts. FIESTA sequences allowed the visualization of cyst membrane in 87.2% of the parasites evaluated, FLAIR in 38.3%, SPGR in 23.4%, and T2 in 17.0%. The superiority of FIESTA sequences over the other three imaging methods was statistically significant (P<0.001). Scolices were detected by FIESTA twice as much as the other sequences did, although this difference was not significant (P>0.05). Differences in signal intensity between CSF and parasite cysts were significant in FIESTA (P<0.0001), SPGR (P<0.0001), and FLAIR (P=0.005) sequences. For the first time, the usefulness of 3D MRI sequences to diagnose T. solium cysts located in the basal cisterns of the subarachnoid space was demonstrated. The routine use of these sequences could favor an earlier diagnosis and greatly improve the prognosis of patients affected by this severe form of the disease.

Keywords: Basal subarachnoid cyst; Diagnosis; MRI 3D sequences; Mexico; Neurocysticercosis.