MRI diagnosis of dural sinus—Cortical venous thrombosis: Immediate post-contrast 3D GRE T1-weighted imaging versus unenhanced MR venography and conventional MR sequences
Introduction
Cerebral dural venous sinus (DVS) thrombosis is a relatively uncommon disorder when compared with other stroke etiologies. It occurs in three to four people per one million and is responsible for nearly 1–2% of strokes in young adults [1], [2]. Its incidence is probably underestimated due to lack of noninvasive accurate imaging modalities and challenging interpretation of available MRI sequences [3], [4]. Early diagnosis and treatment are crucial for accurate management. In untreated patients, DVS thrombosis can cause impaired consciousness, coma, and death. Etiologic factors of DVS thrombosis are classified in two main groups, (i) local; such as trauma, adjacent infections like mastoiditis, neoplastic invasion or compression, and (ii) systemic; such as protein S and protein C deficiencies, a peripartum state, oral contraceptive use, and hypercoagulable states due to malignancy. Symptoms and survey of DVS thrombosis depend on duration, extension and location of thrombosis [4]. Therefore, early diagnosis and explaining location and extension of the thrombosis are very important.
Magnetic resonance imaging (MRI) is frequently performed to detect cerebral DVS thrombosis due to its superiority in evaluation of not only the DVS thrombosis itself, also cerebral parenchymal pathologies. MRI does not require radiation exposure or iodinated contrast medium, therefore, it can be repeated safely for several times during follow-up [5]. Currently, most commonly used MRI techniques are conventional sequences and un-enhanced MR venography such as time-of-flight (TOF) and Phase-contrast (PC), and contrast-enhanced MR venography. The appearance of the thrombosis can vary according to its stage in conventional MRI sequences. An acute thrombus may be isointense, whereas, subacute thrombus may be hyperintense according to brain parenchyma on spin-echo (SE) T1-weighted images. On SE T2-weighted images it may be hypointense and resemble flow void, and hyperintense on initial MR examination. On the other hand, thrombus may lead to a filling defect on MR venography. Similarly, empty delta sign is seen on contrast-enhanced MR venography [3].
Volumetric three-dimensional (3D) gradient recalled echo (GRE) T1-weighted images, in particular the contrast enhanced ones, are relatively the best MRI sequences in evaluation of the DVS and cortical veins. GRE MR sequences allow acquisition of T1-weighted 3D data sets of the brain that can be post-processed and reformatted to provide images in multiple planes, so-called multiplanar reconstruction [6]. For this purpose, slices of 1 mm thickness are gained with isotropic voxels. This allows acquisition of images with high spatial resolution and less flow artifacts in a reasonable time for clinical use, owing to its GRE nature.
The aim of this article is to compare the diagnostic value of conventional MRI sequences, un-enhanced MR venography and contrast-enhanced 3D GRE T1-weighted images in detection of the DVS and cortical venous thromboses, and to determine the relationship among DVS thrombosis, gender, age, thrombus location, infarction and hemorrhage.
Section snippets
Patients
Approval for this retrospective study was obtained from the institutional review board. Informed patient consent was not required for retrospective review of medical records and imaging studies. We aimed to include all patients with clinically suspected Dural Venous Sinus (DVS) and/or cortical venous thromboses in our institution between January 2011 and October 2014 and in whom non-contrast MR venography and contrast-enhanced 3D GE T1-weighted sequence were obtained in addition to conventional
Results
Among 30 cases (21–70 years old, mean age 40.1) retrospectively found and included in this series with clinically suspected DVS thrombosis and with all required sequences available in good quality, 17 were male (mean age, 35.6 years; age range, 21–70 years) and 13 were female (mean age, 46.1 years; age range, 42–70 years). Based on gold reference standards (obtained by a combination of clinical/laboratory findings, clinical/MRI follow-up and other imaging modalities if available), 24 (80%) out
Discussion
In the diagnoses and follow-up of the DVS and cortical vein thrombosis, conventional MRI sequences, non-enhanced PC (Phase Contrast) or TOF (Time-of-Flight) MR venography, contrast enhanced 3D GRE T1-weighted sequence and contrast-enhanced MR venography are being used, if one wants to avoid an invasive catheter angiography (i.e. DSA). There are several articles dealing with the accuracies of these different techniques [11], [12], [13], [14], [15], [16], [17], [18]. However, in cases with
Conclusion
Contrast-enhanced 3D GE T1-weighted MR images (which can be obtained in about 5 min) has the highest sensitivity, specificity and accuracy in detecting dural sinus and/or cortical venous thrombosis, when compared to PC MR venography and conventional MR images. However, conventional MR sequences and MR venography may provide additional information in some cases, such as those with isolated cortical venous thrombosis and with early subacute thrombus material that is hyperintense on T1- and
References (28)
- et al.
Ischemic stroke in patients under age 45
Neurol Clin
(1992) - et al.
The value of T2*-weighted gradient-echo MRI for the diagnosis of cerebral venous sinus thrombosis
Clin Imaging
(2013) - et al.
Focal brain herniation into giant arachnoid granulation: a rare occurrence
Eur J Radiol Extra
(2011) - et al.
Magnetic resonance imaging of cerebral venous sinus thrombosis
Clin Radiol
(2002) Cerebral venous and sinus thrombosis: incidence and causes in ischemic stroke
Adv Neurol
(2003)- et al.
Dural sinus thrombosis: sources of error in image interpretation
AJR Am J Roentgenol
(2011) - et al.
Imaging of cerebral venous thrombosis: current techniques, spectrum of findings, and diagnostic pitfalls
Radiographics
(2006) - et al.
Dural venous sinus thrombosis following head trauma: possible causes and safe imaging techniques
Childs Nerv Syst
(2013) - et al.
FLASH: clinical three-dimensional magnetic resonance imaging
RadioGraphics
(1988) - et al.
Prognosis of cerebral vein and dural sinus thrombosis: results of the International Study on Cerebral Vein and Dural Sinus Thrombosis (ISCVT)
Stroke
(2004)