Value of constructive interference in steady-state, three-dimensional, Fourier transformation magnetic resonance imaging for the neuroendoscopic treatment of hydrocephalus and intracranial cysts

OBJECTIVE: To assess the value of constructive interference in steady-state , three-dimensional, Fourier transformation (CISS) magnetic resonance imagi ng in the endoscopic management of hydrocephalus and intracranial cysts. METHODS: CISS imaging and T2-weighted imaging were performed for 14 consecu tive patients before and after fenestration procedures, using a flexible en doscope, to treat loculated or multiloculated hydrocephalus (4 patients), a queductal stenosis or obstruction (4 patients), arachnoid cysts (4 Patients ), a cyst of the velum interpositum (1 patient), or an ependymal cyst (1 pa tient). Fifteen fenestration procedures were performed, including one reope ration. RESULTS: Preoperative CISS imaging demonstrated intracystic intraventricula r septa not observed with conventional T2-weighted imaging for 11 of 15 pro cedures and provided better brain tissue/cerebrospinal fluid contrast, allo wing better understanding of the cause of hydrocephalus and the nature of t he cysts. CISS imaging and T2-weighted imaging were equally useful far moni toring postoperative changes in the sizes of ventricles or cysts and the pr esence of flow voids after third ventriculostomies. However, only CISS imag ing clearly demonstrated the site of fenestration for six of the nine patie nts who underwent fenestration procedures. CONCLUSION: CISS imaging provides excellent cerebrospinal fluid/brain tissu e contrast, allowing detailed study of the anatomic features of the ventric ular system and cystic lesions. CISS imaging is valuable for both preoperat ive decision-making and postoperative evaluation.