MRI is not only beneficial in the diagnosis of cerebrospinal fluid (CSF)-related diseases, but also aids in planning the management and post-surgery follow-up of the patients. With recent advances in MRI systems, there are many newly developed sequences and techniques that rapidly enable evaluation of CSF-related disorders with greater accuracy. For a better assessment of this group of disorders, radiologists should follow the developments closely and should be able to apply them when necessary. In this pictorial review, the role of MRI in the evaluation of hydrocephalus, CSF diversion techniques, and other CSF disorders is illustrated. Teaching Points • The 3D-SPACE seems to be most efficient technique for evaluation of hydrocephalus and ventriculostomy. • In complex cases, PC-MRI, 3D-heavily T2W, and/or CE-MRC images may prevent false results of 3D-SPACE. • MRI is beneficial in the diagnosis and management of hydrocephalus and other CSF-related diseases.
11 January 2012 in American Journal of Neuroradiology
SUMMARY: CE-MRC has been in use for the past 15 years and was reported to be a useful method in the evaluation of CSF disorders and hydrocephalus. The use of CE-MRC in conjunction with other MR imaging techniques has been shown to be effective in selected cases for the evaluation of several disorders of cerebrospinal system. CE-MRC has certain advantages over other cisternographic studies with fewer side effects if performed properly. Although intrathecal Gd administration is not widely accepted yet, several recent studies have reported the safety of small-dose intrathecal gadolinium injection. In this review, we describe CE-MRC and review recent applications in several clinical conditions.
The aim of this prospective study was to evaluate the value of unenhanced (three-dimensional constructive interference in steady state (3D-CISS)) and contrast-enhanced MR cisternography (CE-MRC) in detecting the localisation of cerebrospinal fluid (CSF) leak in patients with rhinorrhoea. 17 patients with active or suspected CSF rhinorrhoea were included in the study. 3D-CISS sequences in coronal and sagittal planes and fat-suppressed T1-weighted spin-echo sequences in three planes before and after intrathecal contrast media administration were obtained. Images were obtained of the cribriform plate and sphenoid sinus. In addition, high-resolution CT (HRCT) was performed in order to evaluate the bony elements. The leak was present in 9/17 patients with 3D-CISS and 10/17 patients with CE-MRC. The leak from the cribriform plate to the nasal cavity in six patients and from the sphenoid sinus in four patients was nicely shown by CE-MRC. Eight of those patients were surgically treated, but spontaneous regression of the symptoms in two precluded any intervention. The leak localisations shown with CE-MRC were fully compatible with surgical results. The sensitivities of HRCT, 3D-CISS and CE-MRC for showing CSF leakage were 88%, 76% and 100%, respectively. In conclusion, 3D-CISS is a non-invasive and reliable technique, and should be the first-choice method to localise CSF leak. CE-MRC is helpful in conditions when there is no leak or in complicated cases with a positive beta2-transferrin measurement.
In this work, it is demonstrated that a dual‐drive birdcage coil can be used to reduce the radiofrequency heating of metallic devices during magnetic resonance imaging. By controlling the excitation currents of the two channels of a birdcage coil, the radiofrequency current that is induced near the lead tip could be set to zero. To monitor the current, the image artifacts near the lead tips were measured. The electric field distribution was controlled using a dual‐drive birdcage coil. With this method, the lead currents and the lead tip temperatures were reduced substantially [4.9°C using quadrature excitation], as demonstrated by phantom and animal experiments. The homogeneity of the flip angle distribution was preserved, as shown by volunteer experiments. The normalized root‐mean‐square error of the flip angle distribution was less than 10% for all excitations. The average specific absorption rate increased as a trade‐off for using different excitation patterns. Magn Reson Med, 2013.