Table 3.

At a glance merits and demerits of CT, MRI, and DSA techniques.^{[3,5,11,12,27,44–50]}

Techniques	Traits	Description
CT Venography	Advantages	1.Good visualization of major venous sinuses 2.Simple, less time consuming, and less motion artifacts 3.Useful in claustrophobic patients, pacemaker, or defibrillator.
	Disadvantages	1.Ionizing radiation exposure 2.Diabetes, and CKD patients may develop contrast nephropathy. 3.Poor resolution for small parenchymal lesion.
	Sensitivity and specificity	1.CT and CTV has 95% sensitivity and 91% specificity. 2.Based on the lesion, overall accuracy is 90% to 100%
	Typical findings	1.Hyperdensity and lack of flow in thrombosed sinuses 2.Dense triangle sign, empty delta sign and Cord sign
MR Venography	Advantages	1.No radiation exposure and good delineation of brain parenchyma. 2.Identify both of cortical and deep venous thrombosis. 3.Early ischemic changes can be detected.
	Disadvantages	1.Time consuming, unavailability and produce motion artifacts. 2.Unavailable for claustrophobic patients, and pacemaker. 3.Risk of gadolinium-induced nephrogenic systemic fibrosis
	Sensitivity and specificity	1.Not known; however, MRV with echoplanar T2 susceptibility-weighted image are considered as the most sensitive sequences.
	Typical findings	1.≤1 wk: Isointense in T1 and hypointense in T2W images. 2.Up to 2 weeks: Hyperintense on T1 and T2W images 3.>2 wk: Variable appearances; Hypointense in GRE and SWI images; Hyperintensity in DWI enhancement venous wall, and lack of flow in thrombosed sinuses.
DSA	Advantages	1.Precise dynamic information on collateral venous system. 2.Only performed when planned for an endovascular intervention.
	Disadvantages	1.Invasive procedure with associated procedural risks. 2.Skilled person required. 3.Usually, unavailable outside of tertiary hospital.
	Sensitivity and specificity	1.Not clearly known
	Typical findings	1.Absence of sinus opacification. 2.Venous congestion with dilated cortical, scalp, and facial veins. 3.Reversal of the flow and enlarged collateral venous drainage.

AV = arteriovenous, CT = computed tomography, CKD = Chronic kidney disease, CVT = Cerebral venous thrombosis, CTV = CT venography, DSA = digital subtraction angiography, MRI = magnetic resonance imaging, MRV = magnetic resonance venography, TOF = time-of flight.