Computed tomography in the evaluation of cerebral venous sinus thrombosis

Transcription

1 Computed tomography in the evaluation of cerebral venous sinus thrombosis Poster No.: C-0090 Congress: ECR 2014 Type: Authors: Keywords: DOI: Educational Exhibit J. Avsenik, K. Surlan Popovic; Ljubljana/SI Ischemia / Infarction, Hemorrhage, Embolism / Thrombosis, Contrast agent-intravenous, CT-Angiography, CT, Neuroradiology brain, Emergency, CNS /ecr2014/C-0090 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 8

2 Learning objectives 1. Learning objectives The purpose of our educational exhibit is to describe the role of non-enhanced computed tomography (CT) and computed tomography venography (CTV) in the evaluation of patients with suspected cerebral venous sinus thrombosis (CVST). Learning objectives are: 1. to review the risk factors and the clinical presentation of patients with CVST; 2. to discuss the imaging findings of CVST by using CT and CTV and 3. to illustrate the anatomical distribution of CVST. Background 2. Background CVST is a relatively rare but potentially fatal disease [1,2], presenting clinically with headache, focal neurological deficits, seizures, impairment of consciousness and/or papilledema [3]. Causes and predisposing factors include local conditions such as brain injury, intracranial and regional infection as well as systemic conditions such as hormonal (recent abortion, pregnancy, oral contraceptives), surgery, hypercoagulable disorders, connective tissue disease, malignancy, systemic infection and dehydration [4]. The diagnosis of CVST is typically based on clinical suspicion and imaging confirmation. Despite advances in the recognition of CVST in recent years, diagnosis can be difficult because of the diversity of underlying risk factors [5]. MRI and MR venography have been considered the techniques of choice. CTV on the other hand, is a cheaper, faster and readily available alternative in emergency setting and has been shown to be comparable to MR venography [3]. Page 2 of 8

3 Our work provides a survey of common imaging findings in CVST by using CT and CTV. Additionally, we present imaging findings in our series of 32 patients who were admitted to our neurological emergency department with suspected CVST from October 2011 to April Findings and procedure details 3. Findings and procedure details 3.1 Anatomical distribution Superior sagittal sinus is the most frequent site of thrombosis, followed by transverse sinus, sigmoid sinus and deep venous system [6]. 3.2 Imaging findings Non-enhanced CT Typical imaging finding on non-enhanced CT is a dense clot sign (Fig. 1): a direct visualisation of a hyperattenuating thrombus in the occluded sinus [6,7]. However, hyperattenuation is present in only 25 % of CVST, making this sign insensitive [6,8]. Often, CT shows only indirect signs of CVST. These may include diffuse brain edema, leading to hypodensity of the brain or decreased ventricular size [3]. Parenchymal hemorrhage (Fig. 1) can be seen in one-third of CVST and is typically cortical with subcortical extension [6]. Infarction in a non-arterial location or close to venous sinus is suspicious for CVST; subarachnoid hemorrhage, on the other hand, is rarely observed [9]. CT venography (CTV) CTV provides a highly detailed depiction of the cerebral venous system. Classic CTV finding of CVST is the empty delta sign (Fig. 2): a central intraluminal filling defect that represents a thrombus surrounded by contrast enhanced dural collateral venous channels and cavernous spaces within the dural envelope [6,8,10]. It is typically seen on multiple sections on CTV [6]. Indirect evidence of CVST may be seen as contrast enhancement of the falx and tentorium secondary to venous stasis and hyperemia of the dura mater, which is seen in approximately 20% of cases [3]. Page 3 of 8

4 3.3 Drawbacks Drawbacks of computed tomography include the use of ionizing radiation and, in the case of CTV, the use of iodinated contrast material [6]. In our series of 32 patients, CVST was radiologically confirmed in 12 subjects. The initial non-enhanced CT scan was normal in 3 CVST patients. The most common site of thrombosis (Fig. 3) was transverse sinus (n = 8; 4 on each side), followed by superior saggital sinus (n = 5). Alternative diagnosis was established in 15 subjects, namely sinusitis (n = 7), followed by intracranial hemorrhage (n = 6). One case of supratentorial meningeoma and one case of PRES syndrome were diagnosed by initial CT scan and were later confirmed by MRI. A dense clot sign on CT and empty delta sign on CTV were the most commonly observed findings. Images for this section: Page 4 of 8

5 Fig. 1: Dense clot sign. Direct visualisation of a clot in right transverse sinus (arrow) is known as a dense clot sign. This 34-year old female with extensive cerebral venous sinus thrombosis also had intracerebral hemorrhage in right temporal lobe with subsequent edema (arrowheads). Page 5 of 8

6 Fig. 2: Empty delta sign. Two cases of empty delta sign as seen on CT venography (arrows) in two patients with superior sigittal sinus thrombosis. The low-attenuating center of a triangular area on maximum intensity projection axial image (A) and on reconstructed image in coronary plane (B) is the thrombosed sinus. Fig. 3: Frequency of sinus involvement in 12 patients with cerebral venous sinus thrombosis. Page 6 of 8

7 Conclusion 4. Conclusion CVST is a rare condition, presenting with a wide spectrum of symptoms. Superior sagittal sinus and transverse sinus are the frequent sites of CVST. However, a negative nonenhanced CT scan on admission does not exclude the presence of CVST. Therefore, appropriate use of other imaging modalities is mandatory, whenever there is a high degree of clinical suspicion. Classic imaging signs of CVST include direct visualisation of a clot (a dense clot sign) on CT and empty delta sign on CTV. Indirect signs of CVST are often present and include diffuse brain edema, parenchymal hemorrhage and infarction in a non-arterial location. In emergency setting, CTV represents a rapid, readily available and accurate technique for detecting CVST. Personal information References 1. Dentali F, Gianni M, Crowther MA, Ageno W. Natural history of cerebral vein thrombosis: a systematic review. Blood 2006;108(4): Stam J. Thrombosis of the cerebral veins and sinuses. N Engl J Med 2005;352(17): Poon CS, Chang JK, Swarnkar A, Johnson MH, Wasenko J. Radiologic diagnosis of cerebral venous thrombosis: pictorial review. AJR Am J Roentgenol 2007;189(6 Suppl):S Rodallec MH, Krainik A, Feydy A, Helias A, Colombani JM, Julles MC, Marteau V, Zins M. Cerebral venous thrombosis and multidetector CT angiography: tips and tricks. Radiographics 2006;26 Suppl 1:S5-18; discussion S Saposnik G, Barinagarrementeria F, Brown RD, Jr., Bushnell CD, Cucchiara B, Cushman M, deveber G, Ferro JM, Tsai FY. Diagnosis and management of cerebral venous thrombosis: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke;42(4): Leach JL, Fortuna RB, Jones BV, Gaskill-Shipley MF. Imaging of cerebral venous thrombosis: current techniques, spectrum of findings, and diagnostic pitfalls. Radiographics 2006;26 Suppl 1:S19-41; discussion S42-3. Page 7 of 8

8 7. Teasdale E. Cerebral venous thrombosis: making the most of imaging. J R Soc Med 2000;93(5): Virapongse C, Cazenave C, Quisling R, Sarwar M, Hunter S. The empty delta sign: frequency and significance in 76 cases of dural sinus thrombosis. Radiology 1987;162(3): Oppenheim C, Domigo V, Gauvrit JY, Lamy C, Mackowiak-Cordoliani MA, Pruvo JP, Meder JF. Subarachnoid hemorrhage as the initial presentation of dural sinus thrombosis. AJNR Am J Neuroradiol 2005;26(3): Vogl TJ, Bergman C, Villringer A, Einhaupl K, Lissner J, Felix R. Dural sinus thrombosis: value of venous MR angiography for diagnosis and follow-up. AJR Am J Roentgenol 1994;162(5): Page 8 of 8