Radiological findings in spontaneous cerebrospinal fluid leaks of the temporal bone

Abstract

Background and objective Spontaneous cerebrospinal fluid leak of the temporal bone is an emerging clinical entity for which prompt and accurate diagnosis is difficult given the subtle signs and symptoms that patients present with. This study sought to describe the key temporal bone abnormalities in patients with spontaneous cerebrospinal fluid leak. Methods A retrospective cohort study was conducted of adult patients with biochemically confirmed spontaneous cerebrospinal fluid leak. Demographics and radiological features identified on computed tomography imaging of the temporal bones and/or magnetic resonance imaging were analysed. Results Sixty-one patients with spontaneous cerebrospinal fluid leak were identified. Fifty-four patients (88.5 per cent) underwent both temporal bone computed tomography and magnetic resonance imaging. Despite imaging revealing bilateral defects in over 75 per cent of the cohort, only two patients presented with bilateral spontaneous cerebrospinal fluid leaks. Anterior tegmen mastoideum defects were most common, with an average size of 2.5 mm (range, 1–10 mm). Conclusion Temporal bone computed tomography is sensitive for the identification of defects when suspicion exists. In the setting of an opacified middle ear and/or mastoid, close examination of the skull base is crucial given that this fluid is potentially cerebrospinal fluid.

Outcomes of Spontaneous Cerebrospinal Fluid Leak Repair With Concurrent Eustachian Tube Dysfunction

“…Although our reliance on a patient's history of oETD could have resulted in an exaggerated rate of ETD, the mastoid pneumatization pattern differences between groups supported our clinical categorization. In addition, in evaluation of the imaging features of sCSF leak, we relied on subjective middle ear opacification, but similar scales have been used in the literature (8). Although these data are limited by the evaluation of a single unblinded neuroradiologist, there is potential for measurement bias.…”

“…This suggests that comorbid oETD does not alone require alterations in management. Although the impairment of middle ear ventilation in oETD could theoretically predispose patients with sCSF leaks to present earlier or with more severe disease, patients with oETD have similar demographics, physical examination, and imaging findings to patients without (1,8,12).…”

“…However, the diagnosis of oETD does not rely on imaging, and the lack of a poorly pneumatized mastoid does not necessarily rule out the diagnosis (14,15). Still, patients with sCSF leaks are more often expected to have well-pneumatized patterns on CT (8). Interestingly, 5.8% of patients had clear middle ears, which might not be expected in the setting of a sCSF leak.…”

“…Interestingly, 5.8% of patients had clear middle ears, which might not be expected in the setting of a sCSF leak. However, 80.4% of patients had a current PET or previous myringotomy, which likely allowed for an egress of fluid before imaging, accounting for the clear middle ears (8,33). Furthermore, all patients with clear middle ears had defects identified on CT imaging or intraoperatively.…”

“…sCSF leaks have a preponderance to arise in obese, middle-aged women and can manifest as aural fullness, decreased hearing, and pulsatile middle ear effusions (1,2,5). Diagnosis is made by clinical history and high-resolution computed tomography (CT), which can demonstrate defects of the tegmen tympani or mastoideum with associated opacification of the middle ear or mastoid and supported by β 2 -transferrin (1,(6)(7)(8). Because of an increased risk of meningitis, surgical repair is recommended and can be performed through a transmastoid (TM), middle cranial fossa (MCF), or combined TM-MCF approach (1,2,9,10).…”