Non-Invasive Techniques in the Diagnosis of Pseudotumor Cerebri

Rapid Communication

J Ophthalmol & Vis Sci. 2017; 2(1): 1013.

Non-Invasive Techniques in the Diagnosis of Pseudotumor Cerebri

Hamurcu M¹*, Ciliz DS², Saricaoglu S¹, Koca S¹, Acar SE¹, Sakman B² and Karakurt A¹

¹Ankara Numune Training and Research Hospital, Eye Clinic, Turkey

²Ankara Numune Training and Research Hospital, Raiology Clinic, Turkey

*Corresponding author: Hamurcu M, Ankara Numune Education and Research Hospital, Eye Clinic, Turkey

Received: November 17, 2016; Accepted: February 08, 2017; Published: February 15, 2017

Abstract

Aim: To analyze non-invasive techniques in diagnosis of Pseudotumor Cerebri (PTC).

Methods: Twelve cases diagnosed with PTC (group 1), and 10 healthy controls (group 2) were included in the study. All patients were examined for visual acuity, anterior segment and fundus. Ocular Ultrasonography (USG) was used to measure the anteroposterior diameter of the globe. Orbital and cranial Magnetic Resonance Imaging (MRI) was performed. The data were statistically analyzed, and P<0.05 was considered as statistically significant.

Results: Orbital MRI and USG findings showed statistically significant differences for anteroposterior diameter of the globe, optic nerve thickness, perioptic cerebrospinal fluid space, sella height, posterior scleral flattening, and papillary protrusion (P<0.05). Anteroposterior diameter of the globe on USG was found smaller in group 1 compared to group 2, but the difference was not statistically significant.

Conclusion: Measurement of anteroposterior diameter of globe is an important parameter in the differential diagnosis of papilledema. MRI can be used as a noninvasive technique in the diagnosis and follow-up of PTC patients.

Keywords: Pseudotumor cerebri; Ocular ultrasonography; Magnetic resonance imaging

Introduction

Pseudotumor Cerebri (PTC) is associated with a high intracranial pressure in absence of any intracranial space occupying lesions or hydrocephalus. It is characterized by headache and optic disc edema. Temporary loss of vision and double vision may also be seen. Neurological symptoms are usually absent, but sixth nerve palsy may rarely appear. PTC is usually seen in young or middle- aged women, and its etiology is not known most of the time [1-5].

In patients with papilledema, radiological imaging is used to rule out a neurological emergency. Intracranial structures may be seen in detail on radiological imaging. Some radiological imaging findings that were not considered to be important in the past are now accepted as significant findings [1-5].

In this study, transverse and anteroposterior diameters of globe, optic nerve thickness, and perioptic Cerebrospinal Fluid (CSF) space were measured on orbital MRI images. The anteroposterior diameter of the globe was also measured with orbital A-scan Ultrasonography (USG). Posterior scleral flattening, vertical tortuosity and papillary protrusions were analyzed on sagittal and axial USG images. The results were compared with the MRI findings.

Methods

PTC patients followed in Neuro-ophthalmology Department of Ankara Numune Education and Research Hospital constituted PTC group (group 1, n=12). The patients with normal orbital-cranial MRI findings acted as the controls (group 2, n=10). All participants provided their informed consents. The study was conducted in accordance with the principles of Declaration of Helsinki.

PTC was diagnosed according to modified Dandy criteria: 1) Symptoms and signs that may be associated with a high intracranial pressure (headache, papilledema, etc.). 2) Documented increased CSF opening pressure higher than 25 cm H2O, with normal CSF composition. 3) No abnormal neurological findings except a sixth nerve palsy. 4) Absence of any space occupying lesions on neuro radiological imaging [1-4].

Complete ophthalmological examination including visual acuity, color vision, pupillary reflexes, eye movements, and fundus examination were done in all patients. B-scan ocular USG was performed to examine the optic nerve for presence of optic disk drusen and optic nerve sheath expansion. A-scan ocular USG was performed to determine the anteroposterior diameter of the globe. Humphrey automated static perimetry was used for visual field testing. Pattern Visual Evoked Potential (PVEP) was measured in accordance with ISCEV standards in our Electrophysiology Department, using Metrovision, MonPack visual electrophysiology device. All patients were consulted with Neurology Department, and they had Lumbar Punctures (LP). CSF pressure was evaluated according to the Dandy criteria [1].

Radiological imaging included orbital and cranial MRI. Transverse and anteroposterior diameters of the globe, optic nerve thickness, and perioptic CSF space were measured on axial and coronal orbital images. Posterior scleral flattening, vertical tortuosity, papillary protrusions, and “empty sella” were analyzed on the sagittal and axial views. The same radiologist performed all radiological assessments.

Brain and orbital MRI of all participants were done with a 1.5- T MRI system (Signa Excite, GE Medical Systems, Milwauke, Wis.), using a standard head coil. Orbit was analyzed on axial T1-weighted [repetition time/echo time (120S20/14 ms; section thickness/section interspacing 2.5mm/1mm) and axial T2-eighted (4340/112; 2.5/1] images. The matrix size was 256x224 and FOV was 16cm.

Vertical tortuosity was analyzed on both sagittal and axial planes (Figure 1). Optic nerve curving was analyzed on the sagittal plane. The transverse diameter of the globe was measured on the axial plane, perpendicular to each other from outside to outside of the sclera (medial-lateral), and outside of the sclera to the anterior border of the cornea (anterior-posterior). Optic nerve and perioptic CSF space were analyzed immediately posterior to the globe. CSF space was measured from outside to outside, on axial plane (Figure 2). For sella measurements, a line was drawn from the upper ridge of the sellar dorsum to planum sphenoidale (sella’s upper limit), and the distance between the base of the sella and this line (sellar height) was measured. The height of the pituitary gland and the height of sella were measured, and the values obtained were subtracted. The outline of the sclera was analyzed for loos of arc shape and flattening, in order to analyze scleral flattening and papillary protrusions. Presence of swelling of the optic nerve head into the vitreous space was also searched for.