If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.
Cerebral venous thrombosis (CVT) is a rare condition accounting for <1% of all strokes, with highly variable clinical presentations ranging from a headache to coma.1–4 Although MRI and MR venography have significantly improved early diagnosis, clinical outcomes after treatment remain mixed.5 6
The aims of this document include: (1) to review existing knowledge about the natural history, diagnostic methodology, and treatment modalities/techniques for CVT, and (2) to provide recommendations on management strategies for CVT using the best available evidence, but out of necessity, frequently relying on expert opinion concerning this rare disease. Recommendations follow the American College of Cardiology/American Heart Association (ACC/AHA) classification of recommendation/level of evidence and definition of classes and levels of evidence used in AHA/American Stroke Association (ASA) recommendations.7
Sinus Thrombosis Symptoms And Treatment
The Standards and Guidelines Committee of the Society of Neurointerventional Surgery (SNIS), a multidisciplinary society representing leaders in the field of endovascular therapy for neurovascular disease, prepared this document based on a comprehensive review of English language literature relating to the topic. A literature search using PubMed (US National Library of Medicine) and Ovid (Wolters Kluwer) databases was performed from January 1, 1980, through December 31, 2016. The following key words were used: [(sinus thrombosis) AND ((cerebral veins) OR (cranial sinuses) OR (heparin) OR (thrombectomy) OR (anticoagulation))]. A review of references provided in review articles and textbook chapters was also performed. Studies published in languages other than English were excluded.
The estimated incidence of adult CVT is 1.32 per 100 000 person-years. Among women aged between 31 and 50 years, the incidence is as high as 2.78 per 100 000 person-years.8 9 In children less than 18 years of age, the estimated incidence is 0.67 per 100 000 children per year, with neonates the most affected age group.10 Risk factors and conditions known to be associated with CVT are listed in table 1.8 11 Inherited hypercoagulability including protein C, protein S, antithrombin deficiencies and factor V Leiden or resistance to activated protein C are estimated to account for 25–35% of all occurrences of CVT.12 13 The use of oral contraceptives is associated with a four- to sevenfold increase in the risk of CVT.14 In addition, the risk of CVT in woman using oral contraceptives may increase nearly 35- fold if she is heterozygous for factor V Leiden.15 Around 15% of CVT cases occur in patients without identifiable risk factors or predisposing causes.8 16
Data on the natural history of CVT are limited, as most studies reporting the clinical outcomes of CVT include patients treated with anticoagulation.17 Studies of the true natural history of CVT are available from the ‘pre-heparin’ era or from the placebo arms of the early randomized anticoagulation trials of CVT medical therapy.18–21 Outcomes of these studies are summarized in table 2. Mortality in the small populations of these studies ranged from 14% to 40% in patients who did not receive anticoagulation.
Cerebral And Sinus Vein Thrombosis
An algorithm for the diagnosis and management of CVT. CTV, CT venography; CVT, cerebral venous thrombosis; ICH, intracerebral hemorrhage; LMWH, low molecular weight heparin; MRV, magnetic resonance venography; PRES, posterior reversible encephalopathy syndrome; UHF, unfractionated heparin.
Clinical presentations of CVT are diverse, and are affected by the patient’s age, the interval between onset and hospitalization, location of thrombosis, and extent of the thrombosis.9 22 Common clinical signs and symptoms of CVT include headache, focal neurologic deficits, seizure, and diffuse encephalopathy, while rare symptoms include cavernous sinus syndrome and coma.4 Table 3 summarizes common presentations. The clinical significance and presentations of venous thrombosis depend on the location of the thrombosis and a patient’s venous anatomical disposition, especially collateral pathways. Thus, clinical presentation can be diverse and non-specific. For example, CVT should be excluded before making the diagnosis of idiopathic intracranial hypertension since CVT can present with the insidious development of papilledema.23 Crescendo-type progression of non-specific clinical presentations such as seizure or focal neurological deficit over a few days should raise a strong suspicion, and be followed with appropriate imaging studies for the diagnosis of CVT.22 Venous thromboembolism (deep vein thrombosis in the lower limbs or pulmonary embolism) may develop in patients with CVT.
Neuroimaging findings of CVT are variable and multiple modalities may be required to assess both the venous vascular anatomy and parenchymal complications of edema, hemorrhage, and infarction. Non-contrast CT is non-specific and can be normal in up to 25% of patients.4 Classic signs of acute CVT on non-contrast CT of the head include an increase in attenuation (hyperdensity) of the occluded sinuses or cortical veins and cerebral edema (figure 2A).24 25 Intracerebral hemorrhage occurs in 9–39% and can present as parenchymal, intraventricular or subarachnoid hemorrhage.26–28 A wide range of non-contrast CT accuracy in diagnosing CVT has been reported: 30–100% for sensitivity and 83–100% for specificity. On contrast-enhanced CT, the empty delta sign characterized by an intraluminal filling defect may indicate a thrombus within the superior sagittal sinus.29 The empty delta sign is present in 4–28% of cases of CVT.28–30 Hemoglobin and hematocrit levels correlate with CT attenuation in cerebral venous sinuses, and their high levels may mimic CVT in certain conditions such as polycythemia.31 32 Two studies separately confirmed a Hounsfield unit >70 to be highly specific for acute CVT.31 33
Cerebral Venous Sinus Thrombosis
Right transverse sinus venous sinus thrombosis in a patient with head trauma. (A) Non-contrast CT of the head, axial view, shows a hyperintensity within the right transverse sinus (arrows) measuring >70 Hounsfield units, which is highly specific for acute thrombus. Bilateral frontal lobe hypodensities are consistent with the diagnosis of recent head trauma (arrowheads). (B) T1 and (C) FLAIR images of MRI brain performed 3 days after the initial head CT show an area of increased signal intensity within the right transverse sinus, consistent with subacute thrombus (arrows). (D) Time-of-flight MR venography and (E) contrast-enhanced MR venography demonstrate normal appearance of the superior sagittal sinus and left transverse sinus. No flow signal in the right transvers sinus and right internal jugular vein is seen.
The signal intensity of thrombus on MRI varies over time on T1- andT2-weighted sequences depending on the acuity of CVT (T1 isointensity and T2 hypointensity in the acute stage, and both T1 and T2 hyperintensity in the subacute stage; figure 2B, C).34 T2* gradient echo (GRE) and susceptibility weighted imaging (SWI) are highly accurate conventional MRI sequences in the diagnosis of CVT, owing to their sensitivity for susceptibility effects from hemorrhage/thrombus and blood oxygen level dependent imaging to delineate the venous anatomy, respectively.35 36 Heterogeneous MRI patterns are also observed with diffusion-weighted imaging (DWI) and calculated apparent diffusion coefficient (ADC) mapping in the evaluation for venous infarction in the setting of CVT.37 Although vasogenic edema is characterized by an increase in ADC values and is reversible, persistent lesions with restricted diffusion (low ADC values) are suggestive of cytotoxic edema and infarction, but reversibility can be seen in patients with seizures.38 Venous infarction patterns on MRI differ from arterial territory stroke and are often bilateral, helping distinguish CVT from arterial etiologies.39 Conventional MRI sequences including T1-, T2-, T2*-weighted GRE, SWI, fluid-attenuated inversion recovery (FLAIR), and DWI are more accurate than non-contrast CT, and have an overall sensitivity of 72–84% and specificity of 90–95% for the diagnosis of CVT.39 40 Contrast-enhanced 3D GRE T1-weighted imaging with capability of multiplanar imaging is even more accurate than conventional MRI sequences in detecting CVT (93% sensitivity and 100% specificity).40
Both CT venography (CTV) and MR venography (MRV) are highly accurate in diagnosing CVT when the two imaging modalities are compared directly with each other or with digital subtraction angiography (DSA).41–43 The choice of imaging is based on the assessment of the risk of ionizing radiation and iodinated contrast required for CTV versus contraindications to MRI such as the presence of implantable devices or metallic foreign bodies. The estimated sensitivity and specificity of CTV in diagnosing CVT is 75–100%.41 Two dimensional (2D) time-of-flight MRV does not require the use of gadolinium contrast. Depending on the plane of image acquisition, saturation and nulling of the venous signal can occur, leading to misdiagnosis of CVT with false-positive results for the extent of thrombus or failure to differentiate thrombus from dural sinus hypoplasia.44 45 Three-dimensional (3D) contrast-enhanced MRV is better than time-of flight MRV with multiplanar imaging in providing consistent visibility of the venous anatomy including the large dural venous sinuses, deep venous system, and smaller cortical veins, resulting in improved accuracy in diagnosing CVT (figure 2D).44 46 The reported sensitivity and specificity of 3D contrast-enhanced MRV are 93% and 100%, respectively.40
Cerebral Venous Thrombosis: Causes, Treatment, And Diagnosis
There are limited data on the value of perfusion imaging in the diagnosis and management of CVT. However, these studies are not included in the standard diagnostic imaging algorithm. Studies suggest that changes in cerebral blood flow and volume in CVT may be analogous to the ‘core and penumbra’ phenomenon in arterial ischemic stroke.47–49
Digital subtraction angiography may show (1) non-visualization of dural sinus or cortical vein(s), (2) intraluminal filling defects, and (3) angiographic evidence of venous congestions such as engorgement of cortical veins, visualization of prominent medullary veins or reversal
Right transverse sinus venous sinus thrombosis in a patient with head trauma. (A) Non-contrast CT of the head, axial view, shows a hyperintensity within the right transverse sinus (arrows) measuring >70 Hounsfield units, which is highly specific for acute thrombus. Bilateral frontal lobe hypodensities are consistent with the diagnosis of recent head trauma (arrowheads). (B) T1 and (C) FLAIR images of MRI brain performed 3 days after the initial head CT show an area of increased signal intensity within the right transverse sinus, consistent with subacute thrombus (arrows). (D) Time-of-flight MR venography and (E) contrast-enhanced MR venography demonstrate normal appearance of the superior sagittal sinus and left transverse sinus. No flow signal in the right transvers sinus and right internal jugular vein is seen.
The signal intensity of thrombus on MRI varies over time on T1- andT2-weighted sequences depending on the acuity of CVT (T1 isointensity and T2 hypointensity in the acute stage, and both T1 and T2 hyperintensity in the subacute stage; figure 2B, C).34 T2* gradient echo (GRE) and susceptibility weighted imaging (SWI) are highly accurate conventional MRI sequences in the diagnosis of CVT, owing to their sensitivity for susceptibility effects from hemorrhage/thrombus and blood oxygen level dependent imaging to delineate the venous anatomy, respectively.35 36 Heterogeneous MRI patterns are also observed with diffusion-weighted imaging (DWI) and calculated apparent diffusion coefficient (ADC) mapping in the evaluation for venous infarction in the setting of CVT.37 Although vasogenic edema is characterized by an increase in ADC values and is reversible, persistent lesions with restricted diffusion (low ADC values) are suggestive of cytotoxic edema and infarction, but reversibility can be seen in patients with seizures.38 Venous infarction patterns on MRI differ from arterial territory stroke and are often bilateral, helping distinguish CVT from arterial etiologies.39 Conventional MRI sequences including T1-, T2-, T2*-weighted GRE, SWI, fluid-attenuated inversion recovery (FLAIR), and DWI are more accurate than non-contrast CT, and have an overall sensitivity of 72–84% and specificity of 90–95% for the diagnosis of CVT.39 40 Contrast-enhanced 3D GRE T1-weighted imaging with capability of multiplanar imaging is even more accurate than conventional MRI sequences in detecting CVT (93% sensitivity and 100% specificity).40
Both CT venography (CTV) and MR venography (MRV) are highly accurate in diagnosing CVT when the two imaging modalities are compared directly with each other or with digital subtraction angiography (DSA).41–43 The choice of imaging is based on the assessment of the risk of ionizing radiation and iodinated contrast required for CTV versus contraindications to MRI such as the presence of implantable devices or metallic foreign bodies. The estimated sensitivity and specificity of CTV in diagnosing CVT is 75–100%.41 Two dimensional (2D) time-of-flight MRV does not require the use of gadolinium contrast. Depending on the plane of image acquisition, saturation and nulling of the venous signal can occur, leading to misdiagnosis of CVT with false-positive results for the extent of thrombus or failure to differentiate thrombus from dural sinus hypoplasia.44 45 Three-dimensional (3D) contrast-enhanced MRV is better than time-of flight MRV with multiplanar imaging in providing consistent visibility of the venous anatomy including the large dural venous sinuses, deep venous system, and smaller cortical veins, resulting in improved accuracy in diagnosing CVT (figure 2D).44 46 The reported sensitivity and specificity of 3D contrast-enhanced MRV are 93% and 100%, respectively.40
Cerebral Venous Thrombosis: Causes, Treatment, And Diagnosis
There are limited data on the value of perfusion imaging in the diagnosis and management of CVT. However, these studies are not included in the standard diagnostic imaging algorithm. Studies suggest that changes in cerebral blood flow and volume in CVT may be analogous to the ‘core and penumbra’ phenomenon in arterial ischemic stroke.47–49
Digital subtraction angiography may show (1) non-visualization of dural sinus or cortical vein(s), (2) intraluminal filling defects, and (3) angiographic evidence of venous congestions such as engorgement of cortical veins, visualization of prominent medullary veins or reversal
0 Response to "Remedy Sinus Venous Thrombosis"
Posting Komentar