Giant cisterna chyli: MRI depiction with Gadolinium-DTPA enhancement

AIM: To demonstrate the use of MRI with Gadolinium-DTPA enhancement in the diagnosis of giant cisterna chyli. MATERIALS AND METHODS: The study consisted of contrast enhanced MRT with ul trasound and CT correlation in three patients with a giant cisterna chyli, An analysis of the morphology, location and post-contrast MR signal charact eristics in relation to time was performed. RESULTS: Cisterna chyli has a characteristic lobulated morphology and locat ion but the unenhanced MRT appearances are not specific. The post-Gadoliniu m-DTPA MRI appearances are critically dependent on the time elapsed after i njection of contrast medium. Within the first 5 min, there is no enhancemen t at all, but by 10 min there is early layering of contrast medium evident, which by 30 min produces a clear fluid-fluid level. Delayed images at 4-5 h demonstrate a uniform enhancement of the cisternal contents producing a h omogeneous intermediate signal. All of these features are best visualized o n T1 fast saturation sequences. CONCLUSION: MRI with Gadolinium-DTPA enhancement is valuable in confirming the nature of the lymphatic ducts in the retroperitoneal space and helps to differentiate these normal structures from alternative lesions such as lym phadenopathy and tumour recurrence. (C) 2000 The Royal College of Radiologi sts.