Toward a rational treatment of Chiari I malformation and syringomyelia

2000 ◽  
Vol 8 (3) ◽  
pp. 1-10 ◽  
Author(s):  
Richard G. Ellenbogen ◽  
Rocco A. Armonda ◽  
Dennis W. W. Shaw ◽  
H. Richard Winn
Keyword(s):  
Mr Imaging ◽  
Posterior Fossa ◽  
Phase Contrast ◽  
Chiari I Malformation ◽  
Pathological Findings ◽  
Csf Flow ◽  
Rational Treatment ◽  
Flow Profiles ◽  
Cine Mr ◽  
Chiari I

In patients with Chiari I malformation with and without associated syringomyelia, aberrant cerebrospinal fluid (CSF) dynamics and a spectrum of posterior fossa pathological findings are demonstrated. In this study, the authors test the validity of using prospective cardiac-gated phase-contrast cine-mode magnetic resonance (MR) imaging to define the malformation, delineate its pathophysiology, and assist in implementing a rational treatment plan. Eighty-five cases were prospectively analyzed using cine MR imaging. Sixty-five patients, adults and children, with symptomatic Chiari malformation, with and without syringomyelia, were surgically treated from 1990 to 1999. All patients underwent pre- and postoperative cine MR evaluation. Ten patients were treated after a previous surgical procedure had failed. To establish CSF flow characteristics and normative CSF profiles, 20 healthy volunteers were examined. Compared with normal volunteers, in Chiari I malformation patients with and without syringomyelia, uniformly abnormal craniocervical junction CSF flow profiles were revealed. After intradural exploration, nearly all patients with Chiari I malformation experienced clinical improvement and CSF flow profiles, paralleling those of normal volunteers, were shown. In all patients in whom treatment had failed, abnormal preoperative CSF flow profiles, which correlated with suspected physiological abnormalities and the pathological findings noted at reoperation, were demonstrated. Symptomatic Chiari I malformation is a dynamic process characterized by the impaction of the hindbrain in an abnormal posterior fossa. This compression obstructs the normal venting of CSF in and out of the craniocervical sub-arachnoid space, throughout the cardiac cycle. Therefore, decompression or enlargement of the posterior fossa to establish normal CSF pathways should be the primary goal of surgical intervention. Aberrant CSF flow appears to be only one aspect of the pathological condition found in patients with Chiari I malformation. Arachnoid scarring in the posterior fossa and selective vulnerability of the spinal cord may also be factors in the pathogenesis and maintenance of associated syringomyelia. Phase-contrast cine MR imaging is a useful tool in defining physiological and anatomical problems in patients with Chiari I and syringomyelia, and it can help guide an appropriate primary or salvage surgical therapy.

scholarly journals Cough-Associated Headache in Patients with Chiari I Malformation: CSF Flow Analysis by Means of Cine Phase-Contrast MR Imaging

2011 ◽  
Vol 32 (4) ◽  
pp. 739-742 ◽  
Author(s):  
R.A. Bhadelia ◽  
E. Frederick ◽  
S. Patz ◽  
P. Dubey ◽  
S.H. Erbay ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Phase Contrast ◽  
Flow Analysis ◽  
Chiari I Malformation ◽  
Csf Flow ◽  
Chiari I ◽  
Cine Phase Contrast

Elucidating the pathophysiology of syringomyelia

1999 ◽  
Vol 91 (4) ◽  
pp. 553-562 ◽  
Author(s):  
John D. Heiss ◽  
Nicholas Patronas ◽  
Hetty L. DeVroom ◽  
Thomas Shawker ◽  
Robert Ennis ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Subarachnoid Space ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Content Type ◽  
Cine Mr ◽  
Spinal Subarachnoid Space ◽  
Chiari I ◽  
Cerebellar Tonsils ◽  
Fine Print

Object. Syringomyelia causes progressive myelopathy. Most patients with syringomyelia have a Chiari I malformation of the cerebellar tonsils. Determination of the pathophysiological mechanisms underlying the progression of syringomyelia associated with the Chiari I malformation should improve strategies to halt progression of myelopathy.Methods. The authors prospectively studied 20 adult patients with both Chiari I malformation and symptomatic syringomyelia. Testing before surgery included the following: clinical examination; evaluation of anatomy by using T1-weighted magnetic resonance (MR) imaging; evaluation of the syrinx and cerebrospinal fluid (CSF) velocity and flow by using phase-contrast cine MR imaging; and evaluation of lumbar and cervical subarachnoid pressure at rest, during the Valsalva maneuver, during jugular compression, and following removal of CSF (CSF compliance measurement). During surgery, cardiac-gated ultrasonography and pressure measurements were obtained from the intracranial, cervical subarachnoid, and lumbar intrathecal spaces and syrinx. Six months after surgery, clinical examinations, MR imaging studies, and CSF pressure recordings were repeated. Clinical examinations and MR imaging studies were repeated annually. For comparison, 18 healthy volunteers underwent T1-weighted MR imaging, cine MR imaging, and cervical and lumbar subarachnoid pressure testing.Compared with healthy volunteers, before surgery, the patients had decreased anteroposterior diameters of the ventral and dorsal CSF spaces at the foramen magnum. In patients, CSF velocity at the foramen magnum was increased, but CSF flow was reduced. Transmission of intracranial pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was partially obstructed. Spinal CSF compliance was reduced, whereas cervical subarachnoid pressure and pulse pressure were increased. Syrinx fluid flowed inferiorly during systole and superiorly during diastole on cine MR imaging. At surgery, the cerebellar tonsils abruptly descended during systole and ascended during diastole, and the upper pole of the syrinx contracted in a manner synchronous with tonsillar descent and with the peak systolic cervical subarachnoid pressure wave. Following surgery, the diameter of the CSF passages at the foramen magnum increased compared with preoperative values, and the maximum flow rate of CSF across the foramen magnum during systole increased. Transmission of pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was normal and cervical subarachnoid mean pressure and pulse pressure decreased to normal. The maximum syrinx diameter decreased on MR imaging in all patients. Cine MR imaging documented reduced velocity and flow of the syrinx fluid. Clinical symptoms and signs improved or remained stable in all patients, and the tonsils resumed a normal shape.Conclusions. The progression of syringomyelia associated with Chiari I malformation is produced by the action of the cerebellar tonsils, which partially occlude the subarachnoid space at the foramen magnum and act as a piston on the partially enclosed spinal subarachnoid space. This creates enlarged cervical subarachnoid pressure waves that compress the spinal cord from without, not from within, and propagate syrinx fluid caudally with each heartbeat, which leads to syrinx progression. The disappearance of the abnormal shape and position of the tonsils after simple decompressive extraarachnoidal surgery suggests that the Chiari I malformation of the cerebellar tonsils is acquired, not congenital. Surgery limited to suboccipital craniectomy, C-1 laminectomy, and duraplasty eliminates this mechanism and eliminates syringomyelia and its progression without the risk of more invasive procedures.

Phase-Contrast Cine Mr Imaging of Normal Aqueductal CSF Flow

1994 ◽  
Vol 35 (2) ◽  
pp. 123-130 ◽  
Author(s):  
F. Barkhof ◽  
M. Kouwenhoven ◽  
P. Scheltens ◽  
M. Sprenger ◽  
P. Algra ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Phase Contrast ◽  
Volume Averaging ◽  
Cortical Atrophy ◽  
Csf Flow ◽  
Caudal Direction ◽  
Cine Mr ◽  
Flow Void ◽  
Phantom Studies ◽  
Cine Phase Contrast

Cine phase-contrast MR imaging was used to study pulsatile CSF flow in the aqueduct in 11 young controls (mean age 30 years) and 9 old controls (mean age 69 years). A high-resolution gradient echo technique and an oblique imaging plane, perpendicular to the aqueduct, was used to avoid volume averaging. Phantom studies confirmed that the technique was accurate. Aqueductal velocity and flux in old controls was higher than in young controls, but the differences were not significant. For all controls together, the averaged peak velocity was 4.2 ± 1.5 cm/s in rostral and −7.8 ± 4.9 cm/s in caudal direction; for the flux it was 0.16 ± 0.10 cm3/s in rostral and −0.29 ± 0.19 cm3/s in caudal direction. Phase-contrast measurements were significantly related to flow-void on modulus MR images, but not with ventricular size or cortical atrophy. The present technique avoids underestimation of aqueductal flow, and therefore reveals higher aqueductal velocity and flux values than previous studies. Factors other than age or atrophy seem to determine aqueductal CSF flow.

Phase-contrast cine MR imaging of normal aqueductal CSF flow

1994 ◽  
Vol 35 (2) ◽  
pp. 123-130 ◽  
Author(s):  
Frederik Barkhof ◽  
M. Kouwenhoven ◽  
P. Scheltens ◽  
M. Sprenger ◽  
P. Algra ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Phase Contrast ◽  
Csf Flow ◽  
Cine Mr

scholarly journals Elucidating the pathophysiology of syringomyelia

1999 ◽  
Vol 7 (2) ◽  
pp. E1 ◽  
Author(s):  
John D. Heiss ◽  
Nicholas Patronas ◽  
Hetty L. DeVroom ◽  
Thomas Shawker ◽  
Robert Ennis ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Pulse Pressure ◽  
Subarachnoid Space ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Imaging Studies ◽  
Cine Mr ◽  
Spinal Subarachnoid Space ◽  
Chiari I ◽  
Cerebellar Tonsils

Object Syringomyelia causes progressive myelopathy. Most patients with syringomyelia have a Chiari I malformation of the cerebellar tonsils. Determination of the pathophysiological mechanisms underlying the progression of syringomyelia associated with the Chiari I malformation should improve strategies to halt progression of myelopathy. Methods The authors prospectively studied 20 adult patients with both Chiari I malformation and symptomatic syringomyelia. Testing before surgery included the following: clinical examination; evaluation of anatomy by using T1-weighted magnetic resonance (MR) imaging; evaluation of the syrinx and cerebrospinal fluid (CSF) velocity and flow by using phase-contrast cine MR imaging; and evaluation of lumbar and cervical subarachnoid pressure at rest, during the Valsalva maneuver, during jugular compression, and following removal of CSF (CSF compliance measurement). During surgery, cardiac-gated ultrasonography and pressure measurements were obtained from the intracranial, cervical subarachnoid, and lumbar intrathecal spaces and syrinx. Six months after surgery, clinical examinations, MR imaging studies, and CSF pressure recordings were repeated. Clinical examinations and MR imaging studies were repeated annually. For comparison, 18 healthy volunteers underwent T1-weighted MR imaging, cine MR imaging, and cervical and lumbar subarachnoid pressure testing. Compared with healthy volunteers, before surgery, the patients had decreased anteroposterior diameters of the ventral and dorsal CSF spaces at the foramen magnum. In patients, CSF velocity at the foramen magnum was increased, but CSF flow was reduced. Transmission of intracranial pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was partially obstructed. Spinal CSF compliance was reduced, whereas cervical subarachnoid pressure and pulse pressure were increased. Syrinx fluid flowed inferiorly during systole and superiorly during diastole on cine MR imaging. At surgery, the cerebellar tonsils abruptly descended during systole and ascended during diastole, and the upper pole of the syrinx contracted in a manner synchronous with tonsillar descent and with the peak systolic cervical subarachnoid pressure wave. Following surgery, the diameter of the CSF passages at the foramen magnum increased compared with preoperative values, and the maximum flow rate of CSF across the foramen magnum during systole increased. Transmission of pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was normal and cervical subarachnoid mean pressuree and pulse pressure decreased to normal. The maximum syrinx diameter decreased on MR imaging in all patients. Cine MR imaging documented reduced velocity and flow of the syrinx fluid. Clinical symptoms and signs improved or remained stable in all patients, and the tonsils resumed a normal shape. Conclusions The progression of syringomyelia associated with Chiari I malformation is produced by the action of the cerebellar tonsils, which partially occlude the subarachnoid space at the foramen magnum and act as a piston on the partially enclosed spinal subarachnoid space. This creates enlarged cervical subarachnoid pressure waves that compress the spinal cord from without, not from within, and propagate syrinx fluid caudally with each heartbeat, which leads to syrinx progression. The disappearance of the abnormal shape and position of the tonsils after simple decompressive extraarachnoidal surgery suggests that the Chiari I malformation of the cerebellar tonsils is acquired, not congenital. Surgery limited to suboccipital craniectomy, C-1 laminectomy, and duraplasty eliminates this mechanism and eliminates syringomyelia and its progression without the risk of more invasive procedures.

scholarly journals Intraoperative Phase Contrast MRI Analysis of Cerebrospinal Fluid Velocities During Posterior Fossa Decompression for Chiari I Malformation

2019 ◽  
Vol 51 (5) ◽  
pp. 1463-1470
Author(s):  
Nader Delavari ◽  
Anthony C. Wang ◽  
Jayapalli Rajiv Bapuraj ◽  
Frank Londy ◽  
Karin M. Muraszko ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Posterior Fossa ◽  
Phase Contrast ◽  
Chiari I Malformation ◽  
Posterior Fossa Decompression ◽  
Phase Contrast Mri ◽  
Fluid Velocities ◽  
Chiari I

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

2001 ◽  
Vol 11 (1) ◽  
pp. 1-10 ◽  
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.

scholarly journals Changes in cerebrospinal fluid flow assessed using intraoperative MRI during posterior fossa decompression for Chiari malformation

2015 ◽  
Vol 122 (5) ◽  
pp. 1068-1075 ◽  
Author(s):  
Aaron E. Bond ◽  
John A. Jane ◽  
Kenneth C. Liu ◽  
Edward H. Oldfield
Keyword(s):  
Posterior Fossa ◽  
Intraoperative Imaging ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Intraoperative Mri ◽  
Cine Mri ◽  
Posterior Fossa Decompression ◽  
Csf Flow ◽  
Chiari I ◽  
Adequate Decompression

OBJECT The authors completed a prospective, institutional review board–approved study using intraoperative MRI (iMRI) in patients undergoing posterior fossa decompression (PFD) for Chiari I malformation. The purpose of the study was to examine the utility of iMRI in determining when an adequate decompression had been performed. METHODS Patients with symptomatic Chiari I malformations with imaging findings of obstruction of the CSF space at the foramen magnum, with or without syringomyelia, were considered candidates for surgery. All patients underwent complete T1, T2, and cine MRI studies in the supine position preoperatively as a baseline. After the patient was placed prone with the neck flexed in position for surgery, iMRI was performed. The patient then underwent a bone decompression of the foramen magnum and arch of C-1, and the MRI was repeated. If obstruction was still present, then in a stepwise fashion the patient underwent dural splitting, duraplasty, and coagulation of the tonsils, with an iMRI study performed after each step guiding the decision to proceed further. RESULTS Eighteen patients underwent PFD for Chiari I malformations between November 2011 and February 2013; 15 prone preincision iMRIs were performed. Fourteen of these patients (93%) demonstrated significant improvement of CSF flow through the foramen magnum dorsal to the tonsils with positioning only. This improvement was so notable that changes in CSF flow as a result of the bone decompression were difficult to discern. CONCLUSIONS The authors observed significant CSF flow changes when simply positioning the patient for surgery. These results put into question intraoperative flow assessments that suggest adequate decompression by PFD, whether by iMRI or intraoperative ultrasound. The use of intraoperative imaging during PFD for Chiari I malformation, whether by ultrasound or iMRI, is limited by CSF flow dynamics across the foramen magnum that change significantly when the patient is positioned for surgery.

Osteopetrosis with Chiari I malformation: presentation and surgical management

2011 ◽  
Vol 7 (4) ◽  
pp. 369-374 ◽  
Author(s):  
Brian J. Dlouhy ◽  
Arnold H. Menezes
Keyword(s):  
Mr Imaging ◽  
Posterior Fossa ◽  
Autosomal Dominant ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Posterior Fossa Decompression ◽  
Imaging Data ◽  
Inherited Disorders ◽  
Chiari I ◽  
Autosomal Dominant Osteopetrosis

Osteopetrosis is a heterogeneous group of rare, inherited disorders of the skeleton that results in neurological manifestations due to restriction of growth of cranial foramina and calvarial thickening. A 25-year-old woman with a history of autosomal dominant osteopetrosis presented to the authors' institution with headache worsened by exertion and radiating from the occipital region forward with episodes of choking/coughing when eating and a loss of gag reflex on physical examination. On MR imaging, she was found to have severe posterior fossa calvarial thickening resulting in a small posterior fossa and tonsillar ectopia of 9 mm and compression and deformation of the brainstem. She underwent posterior fossa craniectomy, foramen magnum decompression, and partial C-1 laminectomy with external durotomy. The patient did well postoperatively with resolution of symptoms. This case describes a new neurological manifestation of autosomal dominant osteopetrosis. To the authors' knowledge, this report represents the first described case of extreme posterior fossa calvarial thickening from autosomal dominant osteopetrosis with associated Chiari I malformation (CM-I) requiring posterior fossa decompression and extradural decompression. Given previously published MR imaging data that demonstrate the association of osteopetrosis and CM may be more common than in this case alone, the authors discuss the need for further investigation of the incidence of CM-I in patients with autosomal dominant osteopetrosis. Additionally, they review osteopetrosis and other diagnoses of calvarial hyperostosis presenting as CM-I.

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