Using Optical Coherence Tomography as a Surrogate of Measurements of Intracranial Pressure in Idiopathic Intracranial Hypertension

Abstract

IMPORTANCEThere is an unmet need for noninvasive biomarkers of intracranial pressure (ICP), which manifests as papilledema that can be quantified by optical coherence tomography (OCT) imaging.OBJECTIVE To determine whether OCT of the optic nerve head in papilledema could act as a surrogate measure of ICP. DESIGN, SETTING, AND PARTICIPANTSThis longitudinal cohort study used data collected from 3 randomized clinical trials that were conducted between April 1, 2014, and August 1, 2019. Participants who were female and had active idiopathic intracranial hypertension were enrolled from 5 National Health Service hospitals in the UK. Automated perimetry and OCT imaging were followed immediately by ICP measurement on the same day. Cohort 1 used continuous sitting telemetric ICP monitoring (Raumedic Neurovent P-tel device) on 1 visit. Cohort 2 was evaluated at baseline and after 3, 12, and 24 months and underwent lumbar puncture assessment of ICP. MAIN OUTCOMES AND MEASURESOptical coherence tomography measures of the optic nerve head and macula were correlated with ICP levels, Frisén grading, and perimetric mean deviation. The OCT protocol included peripapillary retinal nerve fiber layer, optic nerve head, and macular volume scans (Spectralis [Heidelberg Engineering]). All scans were validated for quality and resegmented manually when required.RESULTS A total of 104 women were recruited. Among cohort 1 (n = 15; mean [SD] age, 28.2 [9.4] years), the range of OCT protocols was evaluated, and optic nerve head central thickness was found to be most closely associated with ICP (right eye: r = 0.60; P = .02; left eye: r = 0.73; P = .002). Subsequently, findings from cohort 2 (n = 89; mean [SD] age, 31.8 [7.5] years) confirmed the correlation between central thickness and ICP longitudinally (12 and 24 months). Finally, bootstrap surrogacy analysis noted a positive association between central thickness and change in ICP at all points (eg, at 12 months, a decrease in central thickness of 50 μm was associated with a decrease in ICP of 5 cm H 2 O). CONCLUSIONS AND RELEVANCEIn this study, optic nerve head volume measures on OCT (particularly central thickness) reproducibly correlated with ICP and surrogacy analysis demonstrated its ability to inform ICP changes. These data suggest that OCT has the utility to not only monitor papilledema but also noninvasively prognosticate ICP levels in idiopathic intracranial hypertension.

Non-invasive Estimation of Pulsatile and Static Intracranial Pressure by Optical Coherence Tomography

“…37 Previous studies of ONHH in relationship to ICP vary. Two studies 17,18 demonstrated a correlation between the height of the optic nerve head and invasively measured mean ICP. Similarly, a second study found a trend towards a decrease in ONHH after lowering the CSF opening pressure.…”

“…[13][14][15] The OCT methodology measures the re ection of back-scattered light and allows for detection and quanti cation of even subtle morphological changes in the retina and the optic nerve. 16 In patients with idiopathic intracranial hypertension (IIH), 17 the mean ICP, measured using a telemetric parenchymal ICP probe, correlated with OCT measures of the optic nerve head.…”

Current Perspectives on Idiopathic Intracranial Hypertension without Papilloedema

“…Advances in neurosurgical hardware now allow for accurate “beat to beat” measurement of ICP through telemetric monitoring [ 21 ], and are recently providing unique insights into IIH [ 22 , 23 ]. Progress is being made in non-invasive ways to act as a surrogate measure of ICP in those with IIH including optical coherence tomography [ 24 , 25 , 26 ] and ultrasound, as are further discussed in Section 7 .…”

Non-invasive detection of intracranial pressure related to the optic nerve

“…Over the years, non-invasive methods for measuring ICP have emerged, including fundoscopy examinations and optical coherence tomography (OCT) (21), flash visual evoked potential (VEP) (22), IOP and venous ophthalmodynamometry (23), tympanic membrane displacement (24), electroencephalogram (25), retinal blood pressure (26), blood flow velocity pulsatility index (27), and cerebral blood flow (28). Due to the large variation and difficulty in implementation, some of these methods are gradually reduced, however, there are several non-invasive methods to detect ICP, which are considered to be more useful.…”

“…OCT is a sensitive and accurate method for detecting optic nerve head lesions. In a cohort study of 104 IIH patients, Vijay et al found that the central thickness of the optic nerve head examined by OCT was closely related to ICP (right eye: r=0.60, P=0.02; left eye: r=0.73, P=0.002) (21). There was a longitudinal correlation between the central thickness of the optic nerve head and ICP (12 and 24 months)and a positive correlation between the central thickness of the optic nerve head and ICP at all points (73).…”