Radiological Characteristics in Rathke's Cleft Cyst

ABSTRACT

OBJECTIVE: The study is conducted to define the preoperative radiological findings of Rathke's cleft cysts (RCCs) differentiating these lesions from other sellar/parasellar cystic tumors. METHODS: A retrospective study of 65 patients with RCC patients from two institutes (53 cases / 12 cases) was performed. All patients had preoperative magentic resonance imaging(MRI) studies, and computed tomography(CT) studies were available in 25 patients. RESULTS: Calcification detectable on CT scanning was present in only 8% of RCC patients. Of the patients who were available for precontrast CT images, 48% had cysts of low attenuation, 28% had cysts of the same attenuation, and 24% had cysts of increased attenuation relative to the brain. Of the patients who had postcontrast CT images, 84% showed no significant change following contrast agent administration, and 16% demonstrated rim enhancement. MR imaging revealed multiple patterns. In T1-weighted sequences, 55.4% showed hyperintense signals, 27.7% showed hypointense signals, 12.3% showed isointense signals, and we saw a mixed-intense signal in 4.6%. In T2-weighed images, we observed a hyperintense signal in 60%, a hypointense signal in 20%, a mixed-intense signal in 13.8%, and an isointense signal in the remaining 6.2%. In Gd-DTPA enhanced images, 72.3% of the 65 patients showed no enhancement either of the cyst contents or of the cyst wall, and 27.7% demonstrated rim enhancement. Forty-five of the 65 patients were preoperatively diagnosed as RCCs. CONCLUSION: RCCs show variable CT and MRI characteristics. There is no unique finding for this pathology. Thus, even with CT and MRI studies, differential diagnosis with other cystic lesions of the sellar/parasellar region remains difficult.