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Show Journal of Neuro- Ophthalmology 20( 1): 12- 13, 2000. Magnetic Resonance Venography in Idiopathic Pseudotumor Cerebri i 2000 Lippincott Williams & Wilkins, Inc., Philadelphia Andrew G. Lee, MD, and Paul W. Brazis, MD Objective: To inform clinicians about the use of magnetic resonance ( MR) venography in idiopathic pseudotumor cerebri. Materials and Methods: A prospective study to evaluate for the presence or absence of dural sinus thrombosis using MR imaging and MR venography of the brain in 22 consecutive young, female, overweight patients with typical pseudotumor cerebri. Results: None of the 22 MR imaging and MR venography studies showed . venous sinus thrombosis. Conclusion: Magnetic resonance venography might not add significantly to the evaluation of typical idiopathic pseudotumor cerebri but may be indicated in atypical cases ( e. g., male, thin, or elderly patients). Key Words: Magnetic resonance venography- Pseudotumor cerebri. Idiopathic pseudotumor cerebri ( PTC) typically affects young obese women. The diagnostic criteria ( modified Dandy criteria) for PTC include the following: 1) signs and symptoms related to increased intracranial pressure ( e. g., papilledema, headache, transient visual obscurations); 2) no localizing neurologic signs with the exception of unilateral or bilateral sixth nerve palsy; 3) neuroimaging study showing no mass lesion or hydrocephalus, and 4) elevated opening pressure with normal cerebrospinal fluid contents on lumbar puncture ( 1). A syndrome resembling idiopathic PTC, however, may occur because of dural venous sinus occlusion ( 2). Magnetic resonance ( MR) imaging and MR venography of the brain in 22 consecutive young, female, overweight patients with typical PTC were prospectively performed to evaluate for the presence or absence of dural sinus thrombosis. METHODS Consecutive patients referred to the neuroophthalmol-ogy service at two tertiary care institutions ( Baylor Col- Manuscript received August 4, 1999; accepted November 5, 1999. From the Departments of Ophthalmology, Neurology, and Neurosurgery ( AGL), Baylor College of Medicine, Houston, Texas, and the Departments of Ophthalmology and Neurosurgery, the M. D. Anderson Cancer Center, the University of Texas, Houston, Texas; and the Department of Neurology ( PWB), Mayo Clinic Jacksonville, Jacksonville, Florida. Dr. Lee is now with the Department of Ophthalmology, The University of Iowa Hospital and Clinics, Iowa City, Iowa. Address correspondence and reprint requests to Paul Brazis, MD, Mayo Clinic Jacksonville, 4500 San Pablo Road, Jacksonville, FL 32216. lege of Medicine, Houston, TX; and Mayo Clinic, Jacksonville, FL) with the diagnosis of PTC underwent MR venography at the time of their initial MR scan of the head. Informed consents under our respective institutional review board protocols were obtained in all patients. Patients with papilledema due to intracranial lesions or with abnormal cerebrospinal fluid analysis were excluded. All MR scans were reviewed for venous sinus thrombosis by a neuroradiologist and neuroophthalmolo-gist. Specific signs of venous sinus thrombosis included lack of high- flow signal ( signal void) from a venous sinus that did not appear hypoplastic or aplastic; or partial or complete filling of the sinus by intraluminal low to intermediate signal intensity thrombus on MR scan and MR venography. Inclusion criteria were age younger than 50 years, female, and overweight meeting the criteria for PTC. Exclusion criteria included patients older than 50 years of age, males, or thin patients. RESULTS Twenty- two patients underwent MR scans and time-of- flight MR venography of the head. All 22 patients were young ( younger than 40 years) overweight women. All 22 venograms and MR scans showed no evidence of cerebral venous sinus thrombosis. DISCUSSION Obstruction of intracranial venous sinus drainage may result in increased intracranial pressure and produce a clinical picture identical to idiopathic PTC. Venous sinus thrombosis may in fact be the mechanism for many of the cases of PTC reported in association with systemic and hematologic disorders, including systemic lupus erythematosus, essential thrombocythemia, protein S deficiency, anti- thrombin III deficiency, antiphospholipid syndrome, paroxysmal nocturnal hemoglobinuria, Behcet's disease, meningeal sarcoidosis, hypervitaminosis A, and mastoiditis ( 1). Purvin et al. ( 2) retrospectively reviewed the clinical features of cerebral venous obstruction in 20 patients. MR imaging with standard MR pulse sequences was adequate for the diagnosis, but sinus thrombosis was sometimes missed on the initial study ( five patients). These investigators believed that special pulse sequences such as MR venography might " serve to highlight further the venous obstruction" ( 2). n MRV IN PTC 13 Leker and Steiner ( 3) reported anticardiolipin antibodies in 6 ( 43%) of 14 patients with PTC. Thirteen patients had MR imaging and MR angiography/ venography, and none showed dural sinus thrombosis ( 3). Likewise, Suss-man et al. ( 4) investigated 38 patients with PTC and found antiphospholipid antibodies in 32% of cases. Familial deficiency of antithrombin III, thrombocytosis, polycythemia vera, and increased plasma fibrinogen were also noted in some patients. Angiography was performed in 18 patients, and 3 patients had dural sinus thrombosis. These authors postulated that partial or non-occlusive venous thrombosis might be a factor in idiopathic PTC and recommended screening with venography ( 4). Najim al- Din et al. ( 5) reported a 2- year prospective study of 21 patients with aseptic intracranial venous occlusive disease. Men were more commonly affected than women, and 81% of the patients presented with a clinical picture indistinguishable from idiopathic PTC. Daif et al. ( 6) reported 40 cases of cerebral venous thrombosis from Saudi Arabia, of which 19 ( 47%) had a clinical picture of PTC. MR angiography was not available in this study, and the investigators recommended angiography or brain MRI for patients with PTC. Magnetic resonance venography has been proposed as a rapid, robust technique for the evaluation of the intracranial venous system and is a potentially useful adjunct in the evaluation of suspected venous thrombosis ( 7). Magnetic resonance venography may in fact be the best technique for the evaluation and follow- up of dural sinus thrombosis. Lam et al. ( 8) reported PTC attributable to dural sinus hypertension from cerebral venous outflow obstruction in six patients. These investigators concluded that MR angiography was an effective noninvasive diagnostic tool for cerebral venous thrombosis. Medlock et al. ( 9) reported the evaluation of 13 children with cerebral venous thrombosis diagnosed with MR scan and MR venography. The MR imaging findings in acute dural sinus thrombosis include isointense signal intensity on Tl-weighted images and markedly hyperintense signal on T2- weighted images. Sinus thrombosis in the intermediate stage has high signal intensity on Tl- and T2- weighted images. They concluded that MR scan was superior to other modalities for the diagnosis of cerebral venous thrombosis and that MR angiography was an alternative means to monitor the evolution of the thrombosis and efficacy of therapeutic intervention. Ozsvath et al. ( 10) found MR venography identified dural sinus thrombosis in 8 of 17 patients with suspected thrombosis. In addition, these authors also reported in this series that computed tomography venography might be superior to MR venography in the identification of cerebral veins and dural sinuses and at least equivalent in dural sinus thrombosis. We did not have comparative data using computed tomography venography or cerebral angiography in our patients. In our series of 22 consecutive patients with typical PTC, there was no evidence on MR imaging or MR venography of cerebral venous thrombosis. Based on our limited data and within the limitations of MR imaging and MR venography, we believe that dural sinus thrombosis is not a significant cause in typical PTC ( obese young women with typical signs and symptoms). We recognize, however, the inherent limitations of our study. First, the sample size is small. Second, we purposefully included only patients with typical and idiopathic PTC ( namely young overweight women). Cerebral venous thrombosis may be a more common cause of PTC in male, thin, or elderly patients or patients with systemic disorders that might predispose to sinus thrombosis. The role of MR venography in these patients is undefined, and it may be appropriate to order MR imaging and MR venography for patients with atypical features for idiopathic PTC. Third, all 22 patients had normal MR imaging, and it is uncertain what additional benefit MR venography adds to the evaluation of a patient with suspected cerebral venous thrombosis and normal standard MR imaging. Fourth, because our patients did not undergo catheter angiography, it could be argued that dural sinus thrombosis could have been missed ( false- negative MR venography) in our patients ( 7). Nevertheless, based on our results, we do not believe that MR venography adds significantly to the evaluation of typical PTC in a young, overweight woman. Magnetic resonance venography may still have a role, however, in the evaluation of atypical cases of PTC, including male, thin, or elderly patients- especially if there is an underlying risk factor ( e. g., hypercoagulable or systemic inflammatory disease) for cerebral venous thrombosis. Acknowledgement: Supported in part by an unrestricted grant from Research to Prevent Blindness, Inc., New York, NY. REFERENCES 1. Smith JL. Whence pseudotumor cerebri. J Clin Neuro- ophthalmol 1985; 5: 55- 6. 2. Purvin VA, Trobe JD, Kosmorsky G. Neuro- ophthalmic features of cerebral venous obstruction. Arch Neurol 1995; 52: 880- 5. 3. Leker RR, Steiner I. Anticardiolipin antibodies are frequently present in patients with idiopathic intracranial hypertension. Arch Neurol 1998; 55: 817- 20. 4. Sussman J, Leach M, Greaves M, Malia R, Davies- Jones GAB. Potentially prothrombotic abnormalities of coagulation in benign intracranial hypertension. J Neurol Neurosurg Psychiatry 1997; 62: 229- 33. 5. Najim Al- Din AS, Mubaidin A, Wriekat AL, Alquam M. Risk factors of aseptic intracranial venous occlusive disease. Acta Neurol Scand 1994; 90: 412- 6. 6. Daif A, Awada A, AI- Rajeh S. Cerebral venous thrombosis in adults: a study of 40 cases from Saudi Arabia. Stroke 1995; 26: 1193- 5. 7. Lewin JS, Masaryk TJ, Smith AS, et al. Time- of- flight intracranial MR venography: evaluation of the sequential oblique section technique. AJNR 1994; 15: 1657- 64. 8. Lam BL, Schatz NJ, Glaser JS, Bowen BC. Pseudotumor cerebri from cranial venous obstruction. Ophthalmology 1992; 99: 706- 12. 9. Medlock MD, Olivero WC, Hanigan WC, et al. Children with cerebral venous sinus thrombosis diagnosed with magnetic resonance imaging and magnetic resonance angiography. Neurosurgery 1992; 31: 870- 6. 10. Ozsvath RR, Casey SO, Lustrin ES, et al. Cerebral venography: comparison of CT and MR projection venography. AJR 1997; 169: 1699- 1707. J Neuro- Ophthalmol, Vol. 20, No. 1, 2000 |
