Magnetic resonance imaging in pseudotumor cerebri

Transcription

1 Magnetic resonance imaging in pseudotumor cerebri Poster No.: C-1004 Congress: ECR 2015 Type: Authors: Keywords: DOI: Scientific Exhibit J. Saad 1, F. Marrakchi 2, F. Harbi 1 ; 1 Nejran/SA, 2 Ksour Essaf/TN Head and neck, Eyes, Neuroradiology brain, MR, MR- Angiography, Diagnostic procedure, Cerebrospinal fluid /ecr2015/C-1004 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 13

2 Aims and objectives There have been many attempts in the past to define objective structural signs on crosssectional imaging that would actually identify idiopathic intracranial hypertension patients; most reports regarding the subject conclude that in the appropriate clinical setting, there are several neuroimaging signs that, although not specific, can assist in establishing the diagnosis of idiopathic intracranial hypertension. The cross-sectional imaging signs previously reported to be of value in idiopathic intracranial hypertension include: empty sella turcica, slit-like ventricles, tight subarachnoid spaces, flattening of the posterior sclera, protrusion of the optic nerve (reversal of the optic nerve), enhancement of the optic nerve head, distention of the optic nerve sheath and vertical tortuosity of the optic nerve. The aim of this study was to evaluate the accuracy of these previously reported structural cross-sectional signs in the diagnosis of idiopathic intracranial hypertension and to determine whether magnetic resonance (MR) imaging can be used to predict the presence of elevated intracranial pressure. Methods and materials Retrospective case series of 16 patients with pseudo tumor cerebri and 16 control subjects. Patients were identified using our clinical database of patients with idiopathic intracranial hypertension (IIH). Patients were included if they had an MRI study of the brain performed at our institution from January 2007 through November 2014 and had visual field and lumbar puncture data available for review. All of the 16 control subjects were originally recruited from population of cancer patients of our institution who underwent screening for brain metastasis. Control subjects had no overt signs or symptoms of neurologic disease and had normal enhanced brain MRI. All patients had brain MRI and MR venous angiography. MRI was performed at 1.5 T (GE Healthcare) using a standard head coil. All patients underwent a standardized brain MRI protocol including unenhanced axial diffusion weighted imaging, T1-weighted, T2*-weighted, and T2-weighted sequences, sagittal T1-weighted sequences and thin (3mm slice thickness) fat suppressed T2 axial, coronal and sagittal oblique weighted sequences for orbits. Page 2 of 13

3 All patients except four (10/16) received IV gadolinium contrast material at a standard dose (0.1 mmol/ kg). All patients also underwent MRV concurrent with the MRI evaluation: 10 patients underwent contrast-enhanced MRV and 6 patients, unenhanced MRV. The presence or absence of the following seven neuroimaging signs was measured: (1) flattening of the posterior sclera; (2) enhancement of the prelaminar optic nerve; (3) distension of the perioptic subarachnoid space; (4) intraocular protrusion of the prelaminar optic nerve; (5) vertical tortuosity of the orbital optic nerve; transverse sinus stenosis (6) and (7) empty sella. Fisher's exact test was used to assess the quality of prevalence of the sign in control and disease subjects. The sensitivity, specificity, likelihood ratio positive (LR+) and likelihood ratio negative (LR-) were also calculated to measure the diagnostic strength of the sign. Results Images of 16 idiopathic intracranial hypertension patients and 16 control subjects were reviewed for this study. A patient group considered of 12 females and 4 males, ages years (mean 37.2 years, median 35 years). The control group included 12 females and 4 males, ages years (mean 59.6 years, median 61 years). The IIH patients were younger than the controls (P inferior 0.001) and more likely to be female (P = 0.16). Although the patients and controls deferred in respect of age and gender, this should not have affected comparisons between the two groups and the occurrence of the signs on MRI, as the signs we were looking for were unlikely to be related to age or gender. No associations were found with any of the MRI signs (odds ratio for gender and per decade of age: P superior 2.44 for both. The MR imaging disclosed flattening of the posterior sclera in 80% of patients with pseudotumor cerebri, empty sella in 70%, distension of the perioptic subarachnoid space in 45%, enhancement of the prelaminar optic nerve in 50%, vertical tortuosity of the orbital optic nerve in 40%, and intraocular protrusion of the prelaminar optic nerve in 30% and stenosis of transverse sinus in 25%. Each neuroimaging sign was detected in 5% of control subjects, except for enhancement of the prelaminar optic nerve, which was not detected in control subjects. Five signs were found to have significant association with IIH (P inferior 0.045, Fisher's exact test). These included: Pituitary deformity and empty sella turcica (figure 1), posterior globe flattening (figures 2 and 3), optic nerve sheath distention (figure 2, 3, 4 and 5), optic nerve tortuosity (figure.3, 4, and 5), optic nerve enhancement and transverse venous sinus stenosis (figure 6). Page 3 of 13

4 Three signs were not significantly associated with IIH; these included optic nerve root protrusion (figure.3 and 4), slit-like ventricles and tight CS spaces (P superior 0.05, Fisher's exact test). Based on these MR imaging signs, the examiner was able to predict the presence of elevated intracranial pressure in 90% of cases with pseudotumor cerebri and the absence of elevated intracranial pressure in all control subjects. Discussion: Previously reported MR and computed tomography (CT) studies evaluating the role of cross-sectional brain imaging in IIH have concluded that there are structural signs that are helpful in establishing this diagnosis (3-8). Wisberg evaluated several signs (small ventricles, no visualized cisterns, prominent cisterna magna, empty sella or enlarged optic nerves) using CT in 28 patients (3). There was no control group in the study, this author concluded that some abnormality is seen in 36% of IIH patients. Later studies used controls for comparison and evaluated a variety of signs by CT or MR. The optic nerve sheaths were found to be significantly wider in IIH patients compared with controls and several studies (4, 7, 8). Others noted that in enlarged, elongated subarachnoid space around the optic nerve was indeed more common in IIH patients than in healthy controls but did not find this observation to be statistically significant (6). Flattening of the posterior aspect of the globe was reported to be significantly more prevalent in IIH patients (8). The more extreme form of flattening, protrusion of the head of the optic nerve), was a repeatedly reported as being more common in IIH patients, but this was not statistically significant (4, 7, 8). Enhancement and the vertical tortuosity of the optic nerve were also reported to be significant signs for IIH (8, 12). Brodsky (8) even stated that single examiner could predicts the presence of elevated intracranial pressure in 90% of cases with IIH and the absence of elevated intracranial pressure in all controls. This was based on the following MR: Empty sella, enhancement and vertical tortuosity of the optic nerve. The degree of empty sella turcica had been reported to be more severe in IIH patients a few years early (3, 4). A quantitative MR analysis of the pituitary morphology demonstrates a significant decrease in the pituitary gland to sella turcica area ratio in patient with IIH (5, 13). Although early reports of studies using CT suggested that patients with IIH had slit ventricles (3), our findings concur with all subsequent reports, confirming that the size of the cerebral ventricles and of the subarachnoid spaces are normal in patients with IIH (4, 5, 7, 14-16). The study confirms that the sign of flattening of the posterior aspect of the globe when present is highly suggestive of the diagnosis of IIH and is a fairly accurate sign. It should be kept in mind that these signs can be used as a sign for IIH only when there is no other abnormality on the brain MR that can cause increased intracranial pressure (including signs of venous thrombosis). This is because posterior globe flattening could potentially appear in any condition causing an increase in intracranial pressure and papilledema. Page 4 of 13

5 A recent study using a technique of contrast-enhanced MRV, found that narrowing of the distal transverse sinuses was strongly associated with IIH. It was also shown that application of a simple grading scheme for the degree of stenosis provided a highly sensitive (93%) and specific (93%) test for identifying patients with IIH (2). Transverse sinus stenosis was noted in 25 % of our cases which support further this association. Images for this section: Fig. 1: Sagittal T1 weighted image, shows partially empty sella. Page 5 of 13

6 Fig. 2: Axial fat suppressed T2 weighted image, demontrates widening of peri-optic nerve subarachnoid spaces, flattening of posterior eye globes and tortuous optic nerves. Page 6 of 13

7 Fig. 3: Oblique sagittal fat suppressed T2 wheighted image for right orbit, showing tortuous optic nerve with protrusion of optic nerve head and wide ONS. Page 7 of 13

8 Fig. 4: Oblique sagittal fat suppressed T2 wheighted image for left orbit, showing tortuous optic nerve with protrusion of optic nerve head and wide ONS. Page 8 of 13

9 Fig. 5: Oblique sagittal fat suppressed T2 wheighted image for right orbit, showing tortuous optic nerve, flattening of posterior sclera, protrusion of optic nerve head and wide ONS. Page 9 of 13

10 Fig. 6: Coronal fat supressed T2 weihted image, shows widening of subarachnoid spaces around optic nerves. Page 10 of 13

11 Fig. 7: A narrowed left transverse sinus is seen on MR venography, in addition to ONS enlargement on axial MR imaging. Page 11 of 13

12 Conclusion Elevated intracranial pressure produces a constellation of MR imaging signs that can assist in establishing the diagnosis of pseudotumor cerebri. Brain MRI and MRV significantly increased the diagnostic certainty for IIH if there was no evidence of a mass lesion, hydrocephalus, or sinus thrombosis and at least one of the following signs was present: flattening of the posterior globe, partially empty sella. Personal information References 1. Friedman DI, Jacobson DM. Diagnostic criteria for idiopathic intracranial hypertension. Neurology 2002;59: Farb RI, Vanek I, Scott JN, Mikulis DJ, Willinsky RA, Tomlinson G, terbrugge KG. Idiopathic intracranial hypertension: the prevalence and morphology of sinovenous stenosis. Neurology May 13;60(9): Weisberg LA. Computed tomography in benign intracranial hypertension. Neurology Jul;35(7): Gibby WA, Cohen MS, Goldberg HI, Sergott RC. Pseudotumor cerebri: CT findings and correlation with vision loss. AJR Am J Roentgenol Jan;160(1): Yuh WT, Zhu M, Taoka T, Quets JP, Maley JE, Muhonen MG, Schuster ME, Kardon RH. MR imaging of pituitary morphology in idiopathic intracranial hypertension. J Magn Reson Imaging Dec;12(6): Gass A, Barker GJ, Riordan-Eva P, MacManus D, Sanders M, Tofts PS, McDonald WI, Moseley IF, Miller DH. MRI of the optic nerve in benign intracranial hypertension. Neuroradiology Nov;38(8): Kesler A, Yaffe D, Shapira M, Kott E. Optic nerve sheath enlargement and reversal of optic nerve head in pseudotumor cerebri. Harefuah Apr 1;130(7):457-9, 503. Hebrew. 8. Brodsky MC, Vaphiades M. Magnetic resonance imaging in pseudotumor cerebri. Ophthalmology Sep;105(9): Zagardo MT, Cail WS, Kelman SE, Rothman MI. Reversible empty sella in idiopathic intracranial hypertension: an indicator of successful therapy? AJNR Am J Neuroradiol Nov-Dec;17(10): Jaeschke R1, Guyatt G, Sackett DL. Users' guides to the medical literature. III. How to use an article about a diagnostic test. A. Are the results of the Page 12 of 13

13 study valid? Evidence-Based Medicine Working Group. JAMA Feb 2;271(5): Friedman DI, Jacobson DM. Diagnostic criteria for idiopathic intracranial hypertension. Neurology 2002;59: Rohr A, Dörner L, Stingele R, Buhl R, Alfke K, Jansen O. Reversibility of venous sinus obstruction in idiopathic intracranial hypertension. AJNR Am J Neuroradiol 2007;28: Lim MJ, Pushparajah K, Jan W, Calver D, Lin JP. Magnetic resonance imaging changes in idiopathic intracranial hypertension in children. J Child Neurol 2010;25: Suzuki H, Takanashi J, Kobayashi K, Nagasawa K, Tashima K, Kohno Y. MR imaging of idiopathic intracranial hypertension. AJNR Am J Neuroradiol 2001;22: Vaghela V, Hingwala DR, Kapilamoorthy TR, Kesavadas C, Thomas B. Spontaneous intracranial hypo and hypertensions: An imaging review. Neurol India 2011;59: Dhungana S, Sharrack B, Woodroofe N. Idiopathic intracranial hypertension. Acta Neurol Scand 2010;121: Sylaja PN, Ahsan Moosa NV, Radhakrishnan K, Sankara Sarma P, Pradeep Kumar S. Differential diagnosis of patients with intracranial sinus venous thrombosis related isolated intracranial hypertension from those with idiopathic intracranial hypertension. J Neurol Sci 2003;215: Agid R, Farb RI, Willinsky RA, Mikulis DJ, Tomlinson G. Idiopathic intracranial hypertension: The validity of cross-sectional neuroimaging signs. Neuroradiology 2006;48: Rohr AC, Riedel C, Fruehauf MC, van Baalen A, Bartsch T, Hedderich J, et al. MR imaging findings in patients with secondary intracranial hypertension. AJNR Am J Neuroradiol 2011;32: Lee AG, Brazis PW. Magnetic resonance venography in idiopathic pseudotumor cerebri. J Neuroophthalmol Mar;20 (1):12-3. Page 13 of 13