Intrathecal Gadolinium-Enhanced MR Cisternography in the Evaluation of CSF Leakage

Abstract

BACKROUND AND PURPOSE:Radiologic identification of the location of the CSF leakage is important for proper surgical planning and increases the chance of dural repair. This article describes our experience in analyzing clinically suspected cranial CSF fistulas by using MR imaging combined with the intrathecal administration of a gadolinium-based contrast agent. MATERIALS AND METHODS:A total of 85 consecutive patients with suspected CSF fistulas who presented with persistent or intermittent rhinorrhea or otorrhea lasting for more than 1 month between 2003 and 2007 were included in this study. RESULTS:We observed objective CSF leakage in 64 of 85 patients (75%). The CSF leak was located in the ethmoidal region in 37 patients (58%), in the superior wall of the sphenoid sinus in 8 patients (13%), in the posterior wall of the frontal sinus in 10 patients (15%), in the superior wall of the mastoid air cells in 6 patients (9%), and from the skull base into the infratemporal fossa in 1 patient (2%). Two patients (3%) showed leakage into Ͼ1 paranasal sinus.CONCLUSIONS: MR cisternography after the intrathecal administration of gadopentate dimeglumine represents an effective and minimally invasive method for evaluating suspected CSF fistulas along the skull base. It provides multiplanar capabilities without risk of radiation exposure and is an excellent approach to depict the anatomy of CSF spaces and CSF fistulas. CSF leakage implies abnormal communication between the subarachnoid space and the nasal or middle ear cavity. It is generally classified as traumatic, nontraumatic (ie, spontaneous), or postsurgical in origin, 1 and most cases are traumatic. Approximately 70% of traumatic CSF fistulas close spontaneously within 1 week after injury without surgical intervention.2-4 However, even in cases of mild CSF rhinorrhea or early spontaneous closure, patients remain at risk of recurrent CSF leakage, pneumocephalus, and infectious meningitis. Precise identification of the location of the CSF fistula allows proper surgical planning, increases the chance of dural repair, and can prevent complications. 5,6 Numerous techniques, including plain skull radiography, intraoperative injection of fluorescein dye, positive contrast (iophendylate) studies, and radionuclide cisternography, are all helpful in limited ways.7-12 MR imaging with T2-weighted sequences has been used to localize CSF fistulas. The demonstration of high-signal-intensity fluid extending from the subarachnoid space directly into the adjacent paranasal sinuses or herniation of the brain into a sinus through a bone defect has been the principal diagnostic criterion.2,13-18 However, some or all of these findings can occasionally be observed in the absence of fistula formation on MR images obtained for reasons other than CSF leakage. The most common method for evaluating a patient with suspected CSF rhinorrhea is a combination of thin-section CT and subsequent CT cisternography (CTC). Although high-resolution CT (HRCT) is sufficient to show bony defects in the skull base...

Intrathecal Gadolinium-Enhanced MR Cisternography: A Comprehensive Review

“…4,28,29 The sensitivity of RC for the diagnosis of a CSF fistula is approximately 40%, whereas it varies between 40% and 81% for CTC. 6,30 Both techniques are quite limited in detecting low-flow fistula or hairlike communications. 6 Leakage is characterized by a hyperintense tract between the subarachnoid space and the sinonasal spaces on NCE-MRC.…”

“…21 In these studies, no significant change was observed on physical and neurologic examinations, electroencephalography, and CSF findings of patients following CE-MRC with Ͻ1 mL of intrathecal Gd injection. 2,6,9,10,[12][13][14][15][16][17][22][23][24][25][26] Gd-DTPA has been reported as the safest and most recommended intrathecal contrast agent in human studies. 2,4,6,9,10 In our cohort of approximately 100 patients who had CE-MRC for at past 7 years in 2 different centers, we have not encountered a major complication.…”

“…9,10 CE-MRC can provide both physiologic and morphologic information, unlike NCE-MRC. 6 CE-MRC is a less invasive technique compared with other cisternographic and ventriculographic (radionuclide or MR ventriculography) tests, and it enables use of all the advantages of MR imaging. 9 CE-MRC can be easily performed with other MR imaging examinations (such as PC-MR imaging).…”

“…CT has overcome these limitations; however, both CTC and RC involve radiation exposure, which is a more important factor to consider because cisternographic studies often require consecutive or multiple acquisitions. [2][3][4][5][6] NCE-MRC derived from heavily 3D T2-weighted sequences (such as fast imaging with steady state acquisition, CISS, or sampling perfection with application optimized contrast using different flip angle evolutions) has been developed to overcome the above-mentioned limitations of CTC and RC. [3][4][5] This technique can be helpful in investigating CSF leakage and the fluid dynamics of the ventricular system.…”

“…Intrathecal Gd injection is not approved by the FDA, though its safety has been reported in several pilot studies in Europe. [2][3][4]6,[9][10][11][12][13][14] Tolerance and dose limits of intrathecal Gd injection were established in animal model studies, and different Gd compounds (eg, gadodiamide, gadobenate dimeglumine, and Gd-DTPA) were compared in different experimental animal protocols. 5,[14][15][16][17] High-dose intraventricular Gd injection was reported to result in behavioral and neurologic disturbances (focal seizures, ataxia, latent tremor) with histopathologic changes (loss of oligodendroglia, astrocytic hypertrophy, and eosinophilia); on the other hand, it was concluded that these changes and distur-bance did not occur if the total injected dose wasϽ15 mL (3.3 mmol/g).…”