Comparing invasive with MRI‐derived intracranial pressure measurements in healthy elderly and brain trauma cases: A pilot study

Abstract

Background Intracranial pressure (ICP) is an important physiological parameter in several neurological disorders. Considerable effort has been made to measure ICP noninvasively. MR‐based ICP (MR‐ICP) is a nonempirical method based on principles of cerebrospinal fluid (CSF) physiology, where ICP is obtained from measurements of blood and CSF flows to and from the cranium during the cardiac cycle. Purpose To compare MR‐ICP with invasive ICP measurements obtained using lumbar puncture (LP) or external ventricular drainage (EVD). Study Type Prospective, cross‐sectional, observational study. Subjects Ten cognitively healthy elderly subjects (age 69.6 ± 6.6 years; seven females) and six brain trauma patients (age 36.8 ± 19.7 years; two females). Field Strength Velocity encoding cine phase‐contrast at 1.5 T and 3 T. Assessment MR‐ICP and craniospinal compliance distribution were estimated from arterial inflow and venous outflow to and from cranium, and craniospinal CSF flow at the upper cervical region, measured using cine phase contrast MRI. LP (done 177 ± 163 days after scan) and EVD measurements (at the time of scan) were performed in lateral recumbent and supine positions, respectively. Statistical Tests Linear regression was used to assess the relationships of MR‐ICP with invasive ICP, and the dependency of these measurements on age, weight, height, and BMI. A Shapiro–Wilks test and Bland–Altman plot were respectively used to evaluate the normality and agreement between these two pressure distributions. Student's t‐test was used throughout the analysis to compare differences between the EVD and LP cohorts. Results In the combined cohort, MR‐ICP and invasive ICP were positively correlated (r = 0.95, P < 0.001), with invasive ICP being higher than MR‐ICP by 2.2 mmHg on average. In the healthy cohort, the cranial contribution to total craniospinal compliance was negatively correlated with MR‐ICP (r = −0.90, P < 0.001). Data Conclusion MR‐ICP provides a reliable estimate of ICP, with 14 out of 16 datapoints within the clinically acceptable error. Craniospinal compliance distribution plays a role in modulating ICP in supine position. Level of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:975–981.

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

“…The above non-invasive ICP measurement methods of the optic nerve and its surrounding tissues are currently the focus of research. So far, MRI-ICP and TD-TCD have been more accurate and closer to invasive detection's gold standard (64,65,93). Other technologies cannot directly obtain the values, and it is difficult to estimate ICP.…”

“…However, MRI also has its limitations. It is impractical to transfer a potentially unstable critical patient for a long period, and frequent radiography will result in high costs (64).…”

A mathematical model for predicting intracranial pressure based on noninvasively acquired PC-MRI parameters in communicating hydrocephalus

“…In previous studies [17,18], noninvasive MRI based models were designed to predict ICP based on the ratio of intracranial volume changes to ICP gradients. In those models, arterial blood flow velocity, venous blood flow velocity, and CSF velocity were measured to obtain cranial volume.…”

“…Noninvasive methods that have consequently been explored to estimate the ICP include the use of ultrasound signals to measure cerebral blood flow velocity indices [ 9 ], brain tissue resonance [ 10 ], skull vibrations [ 11 ], transcranial time of flight [ 12 ], optic nerve sheath diameter assessment [ 13 ], venous ophthalmodynamometry [ 14 ], otoacoustic emissions analysis [ 15 ], tympanic membrane displacement sensing [ 16 ], incremental intracranial compliance (and thereby ICP) estimations based on magnetic resonance imaging [ 17 , 18 ], and visual evoked potential recordings [ 19 ]. However, all of these techniques have their limitations and have potentially low clinical utility.…”

Extracranial versus intracranial hydro-hemodynamics during aging: a PC-MRI pilot cross-sectional study

“…The main settings for these PC-MRI sequences were defined according to previous work [18,19]: TR and TE set at the minimum values, field of view: 140 mm × 140 mm, section thickness: 5 mm, flip angle: 25° for vascular flows and 20° for CSF flows, spatial resolution: 0.55 mm × 0.55 mm, and matrix: 256 × 128. Velocity encoding (V enc ) was set at 80 cm/s for blood vessels and at 5 cm/s, and at 10 cm/sec for CSF flows at the spinal and aqueductal levels, respectively.…”