الفهرس 
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Abstract
This work enrolled 35 patients, presented to the department of radiology at the
faculty of medicine, Alexandria University. The patients had clinically approved CSF
rhinorrhea, and imaging was requested for the aim of localizing the site of the defects and
pre-surgical road mapping for the repair of the defects as well as discovering associated
abnormalities. This referral followed an initial assessment by Otorhinolaryngologists
including thorough clinical examination and history taking, followed by B-2 transferrin test
of the collected fluids in all our included cases.
They were eight males and 27 females. Their ages ranged between six and 64 years
with a median age of 46 years. Mean age 42.34 years. Majority of cases were ≥50 years old
group
This work aimed to study the role of combined non-contrast high resolution
computed tomography (HRCT) with bone algorithm and non-contrast magnetic resonance
cisternography (MRC) in accurate localization of the CSF fistulas whether they were
actively leaking or not.
These patients underwent multi-detector high-resolution CT and MRI examinations
in a closed 1.5-tesla Magnet with adherence to adequate technical parameters that ensure
good image quality; this aimed at high spatial and contrast resolution by using standardized
parameters. Usage of intravenous GAD was needed only in four patients with tumoral and
infectious etiologies.
3D heavily T2-weighted sequence is 3D MRI sequence using a high spatial
resolution, to depict small structures surrounded by cerebrospinal fluid (CSF) with both
high contrast and spatial resolution and therefore in our study, 3D heavily T2-weighted
sequence (3D SPACE) provided us with excellent and supreme details for the accurate
identification of the leaking CSF column.
The study included 27 cases with single skull base defects (77.1%) and eight cases
with multiple defects (22.9%)
Regarding the size of the defect: we measured the skull base bony defect in two
different planes (coronal and sagittal planes) and we found that the minimum defect sizes
ranged between 1mm and 13mm. While the maximum defect sizes ranging between 1mm
and 33mm.
The most common cause of CSF leakage in our study was the spontaneous type 17
cases account for 48.6%, followed by traumatic causes whether accidental (nine cases,
25.7%) or iatrogenic (four cases, 11.4%) and the non-traumatic causes were reported as
causes, whether infectious (two cases, 5.7%) or tumoral (three cases, 8.6%).
All spontaneous leaks in our study presented in female patients. This is an important
statistically significant observation, where males are more commonly involved in road
traffic accidents and other causes of accidental injury and related trauma.
Summary
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The most common site of the skull base defects was the cribriform plates of ethmoid
bone and ethmoid roof (12 cases for each 34.3%) followed by sphenoid sinus walls (eight
cases, 22.9%), then the frontal sinus walls (four cases, 11.4%), followed by the petrous
apex and the clivus (three cases for each, 8.6%).
Out of 35 cases; 24 cases presented with active CSF leakage while the remaining 11
cases complained of intermittent leakage described to have inactive CSF fistula.
Seventeen cases had meningoencephalocele associated with the skull base defects.
Meningoencephalocele is seen mainly among ≥50 years age group followed by 30-40 years
age group and the majority of them were female patients 12 cases out of 17
Our study included 19 cases presented by idiopathic intracranial hypertension with
multiple signs confirming the diagnosis including empty sella, bilateral optic hydrops with
papilledema, enlarged arachnoid granulations.
Out of 35 patients, only five cases had recurrent CSF leakage after surgery, they
were four females and one male patient. The most common cause of CSF leakage between
them was iatrogenic etiology in three cases followed by traumatic accidental etiology in
two cases.
A combination of both non-contrast high-resolution CT and MR Cisternography
provided complementary information, with CT demonstrating the bone defect and MR
depicting the leaking CSF column. As a result, the combined sensitivity and specificity
improved to 95% and 100% respectively. Another important finding was that the accuracy
of non-contrast CT was equally good in active and inactive CSF leaks.
Finally, it is to be concluded that, imaging has an indispensable role in accurate
localization of the skull base osteo-dural defects and pre-operative planning for repair.