Association of MRI findings and visual outcome in idiopathic intracranial hypertension

Abstract

Objective: Patients with idiopathic intracranial hypertension (IIH) have elevated intracranial pressure (ICP) without an identifiable cause. The clinical course is variable, resulting in irreversible vision loss in some and a benign course in others. Although MRI findings have been described in IIH, their association with visual outcome has not been evaluated to date.

Materials and methods: Forty-six patients with IIH underwent funduscopic evaluation, visual field testing, lumbar puncture with opening pressure (OP) measurement, and MRI. Patients were stratified into the following groups by visual outcome: group 1, no vision loss (n = 28); group 2, some vision loss (n = 10); and group 3, severe vision loss (n = 8). MRI findings in the orbits, pituitary gland, and optic canals and the frequency of skull base cephaloceles and of transverse sinus (TS) stenosis were assessed by a reviewer blinded to the patients' visual outcome. Demographic, clinical, and MRI findings were evaluated for association with visual outcome.

Results: Patients in group 3 (worst visual outcome) were significantly younger (p = 0.03) and had higher OP (p = 0.04) than patients in the other groups. There were no significant differences in sex, race, or body mass index. Despite worse visual outcomes and sometimes fulminant vision loss, there were no differences in the frequency of orbital MRI findings or TS stenosis, optic canal diameter, and pituitary appearance among the three groups. Group 3 had significantly lower cephalocele frequency than the other groups (p = 0.04).

Conclusion: Although MRI findings may suggest elevated ICP and the diagnosis of IIH, they are not predictive of visual outcome in patients with IIH.

Fig. 1. MRI findings evaluated for in each patient with IIH

A. Orbital findings of ON head protrusion (arrowhead), posterior scleral flattening (thin arrow), and increased orbital peri-ON CSF (thick arrow) on a magnified axial T2-weighted fat-saturated image. B. ON head enhancement and protrusion (arrow) on a magnified sagittal post-contrast volumetric T1-weighted image. C. Pituitary grade. This was graded from I to V using the method of Yuh et al. The pituitary on this magnified mid-sagittal T1-weighted image depicted would be a category IV: superior concavity mild (>2/3) the height of the sella (arrow) D. Optic canal width. Oblique coronal reformats of the volumetric Magnified reformatted volumetric T1-weighted dataset orthogonal to the axis of the intracanalicular ON were generated and the minimal diameter was measured. Arrow points to the ON. E. Cephaloceles. These were defined as CSF or brain and CSF containing structures outside of the expected confines of the cranial vault. This coronal T2-weighted image shows multiple osteodural defects with CSF filling the right mastoid air cells. F. TSS on MRV. This was based on MIP images generated from either contrast-enhanced MRV (n=23) or 2D TOF MRVs (n=19). The image shows a cranio-caudal projection of a contrast-enhanced MRV with bilateral TSS (arrows).

Fig. 1. MRI findings evaluated for in each patient with IIH

A. Orbital findings of ON head protrusion (arrowhead), posterior scleral flattening (thin arrow), and increased orbital peri-ON CSF (thick arrow) on a magnified axial T2-weighted fat-saturated image. B. ON head enhancement and protrusion (arrow) on a magnified sagittal post-contrast volumetric T1-weighted image. C. Pituitary grade. This was graded from I to V using the method of Yuh et al. The pituitary on this magnified mid-sagittal T1-weighted image depicted would be a category IV: superior concavity mild (>2/3) the height of the sella (arrow) D. Optic canal width. Oblique coronal reformats of the volumetric Magnified reformatted volumetric T1-weighted dataset orthogonal to the axis of the intracanalicular ON were generated and the minimal diameter was measured. Arrow points to the ON. E. Cephaloceles. These were defined as CSF or brain and CSF containing structures outside of the expected confines of the cranial vault. This coronal T2-weighted image shows multiple osteodural defects with CSF filling the right mastoid air cells. F. TSS on MRV. This was based on MIP images generated from either contrast-enhanced MRV (n=23) or 2D TOF MRVs (n=19). The image shows a cranio-caudal projection of a contrast-enhanced MRV with bilateral TSS (arrows).

Fig. 1. MRI findings evaluated for in each patient with IIH

A. Orbital findings of ON head protrusion (arrowhead), posterior scleral flattening (thin arrow), and increased orbital peri-ON CSF (thick arrow) on a magnified axial T2-weighted fat-saturated image. B. ON head enhancement and protrusion (arrow) on a magnified sagittal post-contrast volumetric T1-weighted image. C. Pituitary grade. This was graded from I to V using the method of Yuh et al. The pituitary on this magnified mid-sagittal T1-weighted image depicted would be a category IV: superior concavity mild (>2/3) the height of the sella (arrow) D. Optic canal width. Oblique coronal reformats of the volumetric Magnified reformatted volumetric T1-weighted dataset orthogonal to the axis of the intracanalicular ON were generated and the minimal diameter was measured. Arrow points to the ON. E. Cephaloceles. These were defined as CSF or brain and CSF containing structures outside of the expected confines of the cranial vault. This coronal T2-weighted image shows multiple osteodural defects with CSF filling the right mastoid air cells. F. TSS on MRV. This was based on MIP images generated from either contrast-enhanced MRV (n=23) or 2D TOF MRVs (n=19). The image shows a cranio-caudal projection of a contrast-enhanced MRV with bilateral TSS (arrows).

Fig. 1. MRI findings evaluated for in each patient with IIH

A. Orbital findings of ON head protrusion (arrowhead), posterior scleral flattening (thin arrow), and increased orbital peri-ON CSF (thick arrow) on a magnified axial T2-weighted fat-saturated image. B. ON head enhancement and protrusion (arrow) on a magnified sagittal post-contrast volumetric T1-weighted image. C. Pituitary grade. This was graded from I to V using the method of Yuh et al. The pituitary on this magnified mid-sagittal T1-weighted image depicted would be a category IV: superior concavity mild (>2/3) the height of the sella (arrow) D. Optic canal width. Oblique coronal reformats of the volumetric Magnified reformatted volumetric T1-weighted dataset orthogonal to the axis of the intracanalicular ON were generated and the minimal diameter was measured. Arrow points to the ON. E. Cephaloceles. These were defined as CSF or brain and CSF containing structures outside of the expected confines of the cranial vault. This coronal T2-weighted image shows multiple osteodural defects with CSF filling the right mastoid air cells. F. TSS on MRV. This was based on MIP images generated from either contrast-enhanced MRV (n=23) or 2D TOF MRVs (n=19). The image shows a cranio-caudal projection of a contrast-enhanced MRV with bilateral TSS (arrows).

Fig. 1. MRI findings evaluated for in each patient with IIH

A. Orbital findings of ON head protrusion (arrowhead), posterior scleral flattening (thin arrow), and increased orbital peri-ON CSF (thick arrow) on a magnified axial T2-weighted fat-saturated image. B. ON head enhancement and protrusion (arrow) on a magnified sagittal post-contrast volumetric T1-weighted image. C. Pituitary grade. This was graded from I to V using the method of Yuh et al. The pituitary on this magnified mid-sagittal T1-weighted image depicted would be a category IV: superior concavity mild (>2/3) the height of the sella (arrow) D. Optic canal width. Oblique coronal reformats of the volumetric Magnified reformatted volumetric T1-weighted dataset orthogonal to the axis of the intracanalicular ON were generated and the minimal diameter was measured. Arrow points to the ON. E. Cephaloceles. These were defined as CSF or brain and CSF containing structures outside of the expected confines of the cranial vault. This coronal T2-weighted image shows multiple osteodural defects with CSF filling the right mastoid air cells. F. TSS on MRV. This was based on MIP images generated from either contrast-enhanced MRV (n=23) or 2D TOF MRVs (n=19). The image shows a cranio-caudal projection of a contrast-enhanced MRV with bilateral TSS (arrows).

Fig. 1. MRI findings evaluated for in each patient with IIH

A. Orbital findings of ON head protrusion (arrowhead), posterior scleral flattening (thin arrow), and increased orbital peri-ON CSF (thick arrow) on a magnified axial T2-weighted fat-saturated image. B. ON head enhancement and protrusion (arrow) on a magnified sagittal post-contrast volumetric T1-weighted image. C. Pituitary grade. This was graded from I to V using the method of Yuh et al. The pituitary on this magnified mid-sagittal T1-weighted image depicted would be a category IV: superior concavity mild (>2/3) the height of the sella (arrow) D. Optic canal width. Oblique coronal reformats of the volumetric Magnified reformatted volumetric T1-weighted dataset orthogonal to the axis of the intracanalicular ON were generated and the minimal diameter was measured. Arrow points to the ON. E. Cephaloceles. These were defined as CSF or brain and CSF containing structures outside of the expected confines of the cranial vault. This coronal T2-weighted image shows multiple osteodural defects with CSF filling the right mastoid air cells. F. TSS on MRV. This was based on MIP images generated from either contrast-enhanced MRV (n=23) or 2D TOF MRVs (n=19). The image shows a cranio-caudal projection of a contrast-enhanced MRV with bilateral TSS (arrows).