Role of ultrasound as diagnostic tool in evaluation of optic nerve thickness in cases of raised intracranial pressure

Abstract

Head trauma and intracranial pathologies can result in the increased Intra Cranial Pressure (ICP). Early diagnosis is important in the clinical outcome. As the optic nerve has a dural continuation, any increase in ICP will increase the thickness of Optic nerve Sheath Diameter (ONSD). Ultrasound plays a vital role, as it is a non-invasive, portable, reliable, and an economical tool to measure the ONSD. We aim to assess the role of ultrasound as a diagnostic tool in the measurement of ONSD in subjects with raised ICP All patients with CT signs of raised intracranial pressure were taken as cases. Normal CT brain patients were considered as the control group. It was a prospective study that included data of 60 patients (30 Test, 30 Control) for 1 year. Linear probe of high resolution 10MHz on Philips HD 15 ultrasound machine was employed in the evaluation of ONSD in both groups. From the entry point of optic nerve to globe 3mm distance was considered standard in measurement of ONSD. In the control group 14(46.6%) were females, 16(53.3%) were males and in the test group 11(36.6%) females, 19(63.3%) were males. In the control group upper limit of ONSD was 4.8 mm, lower limit 4.3mm, and mean was 4.49 mm. In the test group, the upper limit of ONSD was5.7mm, lower limit 4.8mm, and mean 5.14mm. There is an obvious raise in the thickness of ONSD in the individuals with positive signs of raised ICP in comparison with normal individuals. Being a non-invasive, and economical, portable ultrasound has a pivot role in the diagnosis of the thickness of ONSD thickness earlier than the onset of papilledema.