Chiari II malformation: MR imaging evaluation

Wolpert, S M; Anderson, Mike; Scott, R. Michael; Kwan, ES; Runge, VM

doi:10.2214/ajr.149.5.1033

Cited by 48 publications

(31 citation statements)

References 6 publications

(10 reference statements)

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“…Measurements made in patients with low tonsil-low O/NG position without evidence of spinal dysraphism reveal a mean O/NG position of + 1.8 mm (or 1.8 mm above the plane of the foramen magnum); mean right ton sillar position is -7 .5 mm, and mean left tonsillar posi tion is -6 .4 mm. These data are presented in table 5. These values differ from the normal patients for both groups (significance values of less than 0.001 by t test).…”

Section: Resultsmentioning

confidence: 75%

Obex/Nucleus gracilis Position: Its Role as a Marker for the Cervicomedullary Junction

Quisling

Mickle³

1993

Pediatr Neurosurg

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Traditionally, the decussation for the pyramids has been the designated marker for the cervicomedullary junction. With Chiari malformations abnormal caudal migration of posterior fossa structures occurs, resulting invariably in a low position of the caudal poles of the cerebellar tonsils (i.e. tonsillar heterotopia) and a low position of the cervicomedullary junction. Since there is considerable variability in normal caudal tonsillar position and because the pyramidal decussateons are difficult to image, diagnostic confusion may exist when the cerebellar tonsils reside in an intermediately low position. This study utilized anatomic specimens to establish the normal morphologic relationship between the position of the obex/nucleus gracilis (O/NG) and the pyramidal decussations; the former consistently lies 5–6 mm rostral to the latter. Having established that anatomic relationship, the O/NG position was then used to assess the cervicomedullary junction position in a radioanatomic survey of normal brain MR examinations. This analysis established a mean O/NG position 10–12 mm above the plane of the foramen magnum. The O/NG position was then evaluated in patients with low tonsillar position. This analysis revealed, as expected, that patients with Chiari II malformation exhibited tonsillar and O/NG positions well below the plane of the foramen magnum. It also distinguished between two additional groups of patients with less florid MR findings. These include patients who exhibit minimally low cerebellar tonsils but essentially normal O/NG position; these patients should be considered normal expressing only minor variation of tonsillar position. The remaining patients exhibit evidence of both intermediately low tonsillar and low O/NG positions, suggesting an underlying anomaly of both tonsil and brain-stem development. It is this latter group of patients that might be considered Chiari I malformations.

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Section: Resultsmentioning

confidence: 75%

Obex/Nucleus gracilis Position: Its Role as a Marker for the Cervicomedullary Junction

Quisling

Mickle³

1993

Pediatr Neurosurg

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“…2). However, CT is loo crude to consistently deter mine the presence of partial agenesis [10,14], and MRI is the method of choice.…”

Section: Discussionmentioning

confidence: 99%

“…The overwhelming advantage of MRI in the evalua tion of other congenital abnormalities will replace CT as the procedure of choice due to its noninvasive charac ter, and ability to image midline deformities in the sagit tal plane [10,14].…”

Section: Discussionmentioning

confidence: 99%

Parietal Cephaloceles: Radiographic and Magnetic Resonance Imaging Evaluation

Jt¹,

1988

Pediatr Neurosurg

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Three patients with parietal cephaloceles underwent evaluation and treatment at Duke University Medical Center between 1984 and 1987. All presented within the first 2 years of life with painful swelling near the vertex of the head. All patients had skull films and computed tomography, and two underwent magnetic resonance imaging (MRI). All 3 children had associated hindbrain deformities; two with Dandy-Walker malformation, the third with a Chiari II malformation. Each child eventually developed hydrocephalus. MRI is the procedure of choice to evaluate these patients, providing direct sagittal imaging of the posterior fossa and craniocervical junction, and displaying communication of the cephalocele with intracranial structures as well as associated venous vascular anomalies.

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“…Various malformations have been described including Chiari malformation types I and II, hydrocephalus, tethered cord syndrome, intraspinal lipoma, dermoid and epidermoid cysts, congenital dermal sinus tract, syringohydromyelia (SHM) and diastematomyelia (DM) [1][2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Cervical diastematomyelia and syringohydromyelia in a myelomeningocele patient

1997

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A case of cervical diastematomyelia and syringohydromyelia in a 16-year-old female myelomeningocele patient is reported. Progressive weakness of the upper extremity led to an MR examination of the brain and spine, which revealed hydrocephalus, Chiari II malformation, cervical diastematomyelia with a syringohydromyelic cavity in each hemicord and a large dural sac in the lumbar region. Operative therapy consisted of detethering and shunting of the two syringes. Soon after surgery her symptoms improved. The need for early complete MR imaging of myelomeningocele patients presenting with new symptoms is emphasized.

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Chiari II malformation: MR imaging evaluation

Abstract: The purpose of this study was to explore the value of high-detail MR imaging in the diagnosis of the Chiari II malformation.

Cited by 48 publications

References 6 publications

Obex/Nucleus gracilis Position: Its Role as a Marker for the Cervicomedullary Junction

Obex/Nucleus gracilis Position: Its Role as a Marker for the Cervicomedullary Junction

Parietal Cephaloceles: Radiographic and Magnetic Resonance Imaging Evaluation

Cervical diastematomyelia and syringohydromyelia in a myelomeningocele patient

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