Noninvasive intracranial compliance and pressure based on dynamic magnetic resonance imaging of blood flow and cerebrospinal fluid flow: review of principles, implementation, and other noninvasive approaches

Current techniques for intracranial pressure (ICP) measurement are invasive. All require a surgical procedure for placement of a pressure probe in the central nervous system and, as such, are associated with risk and morbidity. These considerations have driven investigators to develop noninvasive techniques for pressure estimation. A recently developed magnetic resonance (MR) imaging–based method to measure intracranial compliance and pressure is described. In this method the small changes in intracranial volume and ICP that occur naturally with each cardiac cycle are considered. The pressure change during the cardiac cycle is derived from the cerebrospinal fluid (CSF) pressure gradient waveform calculated from the CSF velocities. The intracranial volume change is determined by the instantaneous differences between arterial blood inflow, venous blood outflow, and CSF volumetric flow rates into and out of the cranial vault. Elastance (the inverse of compliance) is derived from the ratio of the measured pressure and volume changes. A mean ICP value is then derived based on a linear relationship that exists between intracranial elastance and ICP. The method has been validated in baboons, flow phantoms, and computer simulations. To date studies in humans demonstrate good measurement reproducibility and reliability. Several other noninvasive approaches for ICP measurement, mostly nonimaging based, are also reviewed. Magnetic resonance imaging–based ICP measurement may prove valuable in the diagnosis and serial evaluation of patients with a variety of disorders associated with alterations in ICP.

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Evaluating the Effect of Decompression Surgery on Cerebrospinal Fluid Flow and Intracranial Compliance in Patients with Chiari Malformation with Magnetic Resonance Imaging Flow Studies

Neurosurgery ◽

10.1227/01.neu.0000143612.60114.2d ◽

2004 ◽

Vol 55 (6) ◽

pp. 1344-1351 ◽

Cited By ~ 39

Author(s):

Anusha Sivaramakrishnan ◽

Noam Alperin ◽

Sushma Surapaneni ◽

Terry Lichtor

Keyword(s):

Magnetic Resonance Imaging ◽

Cerebrospinal Fluid ◽

Magnetic Resonance ◽

Chiari I Malformation ◽

Magnetic Resonance Images ◽

Decompression Surgery ◽

Intracranial Volume ◽

Resonance Imaging ◽

Intracranial Compliance ◽

Chiari I

Abstract OBJECTIVE: To quantify the effect of decompression surgery on craniocervical junction hydrodynamics and on global intracranial compliance (ICC) in patients with Chiari I malformation by use of magnetic resonance measurements of cerebrospinal fluid and blood flow. Studying the effect of decompression surgery may improve our understanding of the pathophysiological characteristics of Chiari I malformation and aid in identifying patients who will benefit from the procedure. METHODS: Twelve patients were studied with a 1.5-T magnetic resonance imaging scanner before and after decompression surgery. Cine phase contrast magnetic resonance images were used to quantify maximum cord displacement, maximum systolic cerebrospinal fluid velocity and volumetric flow rate, and overall ICC. ICC was derived by use of a previously reported method that measures small changes in intracranial volume and pressure that occur naturally with each cardiac cycle. RESULTS: After surgery, changes were documented both in the local hydrodynamic parameters and in ICC. However, only the change in ICC, an average increase of more than 60%, was statistically significant. Increased ICC, which was associated with improved outcome, was measured in 10 of the 12 patients, no significant change was documented in 1 patient, and decreased ICC was measured in 1 patient whose symptoms persisted after surgery. CONCLUSION: An increase in the overall compliance of the intracranial compartment is the most significant and consistent change measured after decompression surgery. Changes in cord displacement, cerebrospinal fluid velocities, and flow in the craniospinal junction were less consistent and less affected by the operation. Thus, ICC may play an important role in the outcome of decompression surgery related to improving symptoms and restoring normal neurological hydrodynamics in patients with Chiari I malformations.

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Imaging-Based Features of Headaches in Chiari Malformation Type I

Neurosurgery ◽

10.1227/neu.0000000000000740 ◽

2015 ◽

Vol 77 (1) ◽

pp. 96-103 ◽

Cited By ~ 15

Author(s):

Noam Alperin ◽

James R. Loftus ◽

Carlos J. Oliu ◽

Ahmet M. Bagci ◽

Sang H. Lee ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Chiari Malformation ◽

Posterior Cranial Fossa ◽

Type I ◽

Intracranial Volume ◽

Resonance Imaging ◽

Chiari Malformation Type I ◽

Intracranial Compliance ◽

Cranial Fossa

Abstract BACKGROUND: Suboccipital cough-induced headaches are considered a hallmark symptom of Chiari malformation type I (CMI). However, non--Valsalva-related suboccipital headaches and headaches in other locations are also common in CMI. The diagnostic significance and the underlying factors associated with these different headaches types are not well understood. OBJECTIVE: To compare cranial morphology and hydrodynamics in 3 types of headaches in CMI to better understand the pathophysiological basis for the different headache characteristics. METHODS: Twenty-two cranial physiological and morphological measures were obtained with specialized magnetic resonance imaging scans from 63 symptomatic pretreated CMI patients, 40 with suboccipital headaches induced by Valsalva maneuvers (34 women; age, 36 ± 10 years), 15 with non--Valsalva-related suboccipital headaches (10 women; age, 33 ± 9 years), 8 with nonsuboccipital non--Valsalva-induced headaches (8 women; age, 39 ± 13 years), and 37 control subjects (24 women; age, 36 ± 12 years). Group differences were identified with the use of the 2-tailed Student t test. RESULTS: Posterior cranial fossa markers of CMI were similar among the 3 headache subtypes. However, the Valsalva-related suboccipital headaches cohort demonstrated a significantly lower intracranial compliance index than the non--Valsalva-related suboccipital headaches cohort (7.5 ± 3.4 vs 10.9 ± 4.9), lower intracranial volume change during the cardiac cycle (0.48 ± 0.19 vs 0.61 ± 0.16 mL), and higher magnetic resonance imaging--derived intracranial pressure (11.1 ± 4.3 vs 7.7 ± 2.8 mm Hg; P = .02). The Valsalva-related suboccipital headaches cohort had smaller intracranial and lateral ventricular volumes compared with the healthy cohort. The non--Valsalva-related suboccipital headaches cohort had reduced venous drainage through the jugular veins. CONCLUSION: Valsalva-induced worsening of occipital headaches appears to be related to a small intracranial volume rather than the smaller posterior cranial fossa. This explains the reduced intracranial compliance and corresponding higher pressure measured in CMI patients with headaches affected by Valsalva maneuvers.

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Magnetic resonance imaging—based measurements of cerebrospinal fluid and blood flow as indicators of intracranial compliance in patients with Chiari malformation

Journal of Neurosurgery ◽

10.3171/jns.2005.103.1.0046 ◽

2005 ◽

Vol 103 (1) ◽

pp. 46-52 ◽

Cited By ~ 83

Author(s):

Noam Alperin ◽

Anusha Sivaramakrishnan ◽

Terry Lichtor

Keyword(s):

Magnetic Resonance Imaging ◽

Blood Flow ◽

Cerebrospinal Fluid ◽

Magnetic Resonance ◽

Chiari Malformation ◽

Resonance Imaging ◽

Intracranial Compliance

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Analysis of magnetic resonance imaging–based blood and cerebrospinal fluid flow measurements in patients with Chiari I malformation: a system approach

Neurosurgical FOCUS ◽

10.3171/foc.2001.11.1.7 ◽

2001 ◽

Vol 11 (1) ◽

pp. 1-10 ◽

Cited By ~ 22

Author(s):

Noam Alperin ◽

Kirti Kulkarni ◽

Ben Roitberg ◽

Francis Loth ◽

Naren K. Pandian ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Mr Imaging ◽

Cardiac Cycle ◽

Chiari I Malformation ◽

Intracranial Volume ◽

Resonance Imaging ◽

Csf Flow ◽

Chiari I ◽

Systolic Phase

Object A pilot study was performed to assess noninvasively the change in intracranial compliance (ICC) and intracranial pressure (ICP) in patients with Chiari I malformation who undergo foramen magnum decompression. The working hypothesis was that the main effect of the decompressive surgery is a change in ICP. Noninvasive cine phase-contrast magnetic resonance (MR) imaging is a motion-sensitive dynamic MR imaging technique that allows for visualization and quantitation of tissue motion and flow. The authors' group has used dynamic phase-contrast MR imaging to visualize and quantify pulsatile blood and cerebrospinal fluid (CSF) flow in the craniospinal system. Methods A system approach has been used to characterize the hemodynamic–hydrodynamic coupling in the craniospinal system and to derive measures for ICC and ICP. Magnetic resonance imaging–based ICC and ICP values are derived from the ratio of the volume and pressure changes that occur naturally during each cardiac cycle. The authors conducted a prospective study of four patients, three of whom were studied before and after decompressive surgery; significant change in MR imaging–derived ICC and ICP values was documented in only one of the three surgically treated patients. A significant change in the dynamics of the intracranial volume change (ICVC) during the cardiac cycle, however, was observed in all three patients. In healthy individuals the ICVC waveform usually consists of the following sequence: monotonic increase in intracranial volume (ICV) during the systolic phase due to increased blood inflow, monotonic decrease in ICV caused by the onset of CSF outflow into the spinal canal, and increase in the venous outflow. A nonmonotonic decline in the ICVC waveform has been observed in all patients with headaches, and a relatively normal waveform was found in those without headaches or whose headaches were resolved or alleviated by the surgery. A “partial-valve” mechanism is proposed as an explanation for the abnormal ICVC dynamics. The monotonic decline in ICVC is interrupted by a “premature” reduction in the CSF outflow. This may be caused by a displacement of the hindbrain into the cervical spinal canal during the systolic phase. This obstructs the CSF flow at the later part of the systolic phase such that the ICV does not continue its gradual decline. Postsurgery, the ICVC waveforms presented a more normal-appearing ICVC dynamics profile. Conclusions Magnetic resonance imaging measurement of transcranial CSF and blood flow may lead to a better understanding of the pathophysiology of Chiari malformations and may prove to be an important diagnostic tool for guiding for the treatment of patients with Chiari I malformation.

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Magnetic resonance imaging biomarkers of cerebrospinal fluid tracer dynamics in idiopathic normal pressure hydrocephalus

Brain Communications ◽

10.1093/braincomms/fcaa187 ◽

2020 ◽

Vol 2 (2) ◽

Author(s):

Per Kristian Eide ◽

Are H Pripp ◽

Geir Ringstad

Keyword(s):

Magnetic Resonance Imaging ◽

Cerebrospinal Fluid ◽

Magnetic Resonance ◽

Normal Pressure Hydrocephalus ◽

Normal Pressure ◽

Idiopathic Normal Pressure Hydrocephalus ◽

Imaging Biomarkers ◽

Resonance Imaging ◽

Intracranial Compliance ◽

The Brain

Abstract Disturbed clearance of toxic metabolites from the brain via cerebrospinal fluid is emerging as an important mechanism behind dementia and neurodegeneration. To this end, magnetic resonance imaging work-up of dementia diseases is largely focused on anatomical derangements of the brain. This study explores magnetic resonance imaging biomarkers of cerebrospinal fluid tracer dynamics in patients with the dementia subtype idiopathic normal pressure hydrocephalus and a cohort of reference subjects. All study participants underwent multi-phase magnetic resonance imaging up to 48 h after intrathecal administration of the contrast agent gadobutrol (0.5 ml, 1 mmol/ml), serving as cerebrospinal fluid tracer. Imaging biomarkers of cerebrospinal fluid tracer dynamics (i.e. ventricular reflux grades 0–4 and clearance) were compared with anatomical magnetic resonance imaging biomarkers of cerebrospinal fluid space anatomy (Evans’ index, callosal angle and disproportional enlargement of subarachnoid spaces hydrocephalus) and neurodegeneration (Schelten’s medial temporal atrophy scores, Fazeka’s scores and entorhinal cortex thickness). The imaging scores were also related to a pulsatile intracranial pressure score indicative of intracranial compliance. In shunt-responsive idiopathic normal pressure hydrocephalus, the imaging biomarkers demonstrated significantly altered cerebrospinal fluid tracer dynamics (ventricular reflux grades 3–4 and reduced clearance of tracer), deranged cerebrospinal fluid space anatomy and pronounced neurodegeneration. The altered MRI biomarkers were accompanied by pressure indices of impaired intracranial compliance. In conclusion, we present novel magnetic resonance imaging biomarkers characterizing idiopathic normal pressure hydrocephalus pathophysiology, namely measures of cerebrospinal fluid molecular redistribution and clearance, which add information to traditional imaging scores of cerebrospinal fluid space anatomy and neurodegeneration.

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Assessment of Cerebrospinal Fluid Hydrodynamics Using Magnetic Resonance Imaging in Postcraniospinal Surgery Patients

Indian Journal of Radiology and Imaging ◽

10.1055/s-0041-1734362 ◽

2021 ◽

Author(s):

Pankaj Arora ◽

Kanica Rawat ◽

Rajiv Azad ◽

Kehkashan Chouhan

Keyword(s):

Magnetic Resonance Imaging ◽

Cerebrospinal Fluid ◽

Magnetic Resonance ◽

Clinical Outcome ◽

Phase Contrast ◽

Flow Dynamics ◽

Resonance Imaging ◽

Csf Flow ◽

Group I ◽

Group Ii

Abstract Objective Aim of this study is to evaluate the effect of craniospinal interventions on cerebrospinal fluid (CSF) flow hydrodynamics and study the correlation of postoperative changes in flow alteration with clinical outcome. Materials and Methods Fifty patients who underwent various craniospinal procedures were studied using conventional and phase-contrast magnetic resonance imaging (PCMRI) protocol. CSF flow quantification was performed at cerebral aqueduct, foramen magnum, C2–3, and D12–L1 vertebral levels with site showing maximal alteration of CSF flow dynamics considered as the region of interest. Velocity encoding was kept at 20 cm/s. Patients with pathology atcraniovertebral junction were considered separately (group I) from others (group II) due to different flow dynamics. Follow-up scans were performed after an interval of 1 month for temporal evaluation of changes in CSF flow dynamics. Results Patients in both groups showed a significant change in peak CSF velocity postoperatively (mean change of 1.34 cm/s in group I and 0.28 cm/s in group II) with bidirectional improvement in flow on cine-phase-contrast qualitative images. Regional pain (82%) and headache (46%) were seen in most of the patients preoperatively. Postoperatively clinical symptoms improved in 59.5%, static in 26.2%, and worsened in 14.3%. In both the groups, an improvement in clinical symptomatology had significant correlation with mean changes in peak CSF velocity postoperatively (p = 0.04 in both groups). Conclusion PCMRI can effectively evaluate changes in CSF flow noninvasively both pre- and postoperatively. This may have potential role in determining clinical outcome and prognosis of patients undergoing procedures in craniospinal axis.

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