Subacute Dural Sinus Thrombosis - Different Image Diagnostic Methods

Clinical History

Sudden worsening of headaches

Imaging Findings

34-year-old female admitted at Emergency Department for headaches with a five-day duration (right hemicrania) with sudden worsening and generalization after a sneeze (Valsalva) and without response to symptomatic medication. Patient was using/taking oral contraceptive pill. Previous depressive syndrome with (self) suspension of medication 3 months before. No personal or familiar important medical history - in particular, no other thrombotic events; no abortions. On neurological examination, there was a doubtful neck rigidity, in a complainant woman. No other neurological signs. Diagnostic imaging evaluation was made by brain CT, followed by venous CT angiography. CT and CT-Venography showed thrombosis of the posterior Superior sagital sinus, straight sinus, vein of Galen and lateral sinuses (more evident at the left) and left jugular vein. She was treated with anticoagulation with improvement and was kept under medical surveillance. Despite the extent of the thrombosis, a MRI study done 5 days after therapy had been initiated showed no signs of parenchyma lesions, namely on the diffusion weighted imaging and the susceptibility weighted imaging.

Discussion

We present a case of a 34-year-old woman that had severe and atypical headaches. Cerebral Venous Thrombosis (CVT) is believed to be more common in women than men and related to pregnancy or the use of oral contraceptives. Many conditions have been linked with CVT; in this case, the only risk factor found was the use of oral contraceptives. Other risk factors, like infections of paranasal sinuses, history of trauma or a pre-existing prothrombotic condition were discarded. Investigation is important because the identification of a risk factor should lead to appropriate therapy, when available. Also, because CVT is usually multifactorial (about 44% of patients have more than one identifiable risk factor), investigation should not be stopped when one cause/risk factor is found. Treatment of CVT combines anticoagulation therapy with symptomatic treatment (ie headaches, seizures, intracranial hypertension) and often clinical improvement precedes resolution of cloth on neuroimaging –as it was in our case. Cerebral venous thrombosis (CVT) is an unusual cause of stroke, and while its real incidence is unknown, there has been a recent increase in its recognition, mostly due to advances in Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) technology. Unlike arterial stroke CVT is more frequent in young adults (about 75% are women). CVT’s outcome is unpredictable, ranging from complete recovery to disability or death; early diagnosis is therefore important so that appropriate therapy can be initiated. Diagnosis is difficulted by the highly variable and unspecific clinical symptoms commonly associated with CVT; it should always be considered in the acute headache differential diagnosis. Clinical suspicion justifies neuroimaging on an emergency basis, and CVT is a diagnosis that must be ruled out. Diagnostic imaging, and especially MRI, is the basis of CVT diagnosis. MRI is very sensitive to the parenchymal changes seen in CVT. Cortical and subcortical high-signal-intensity lesions on FLAIR sequence and T2-weighted imaging may highly suggest CVT when the lesions do not correspond to an arterial territory. Restriction of diffusion on diffusion-weighted imaging (DWI) with a corresponding decrease in the apparent diffusion coefficient (ADC) value is often irreversible in arterial infarction and correlates with a permanent neurologic deficit. Diffusion techniques have been used in CVT to differentiate reversible ischemic tissue from irreversible ischemia. Recent investigations of CVT have revealed that mixed signal intensity on DWI may represent both cytotoxic and vasogenic edema. A decrease of ADC in CVT may not have the same prognostic value as it does in arterial stroke, and venous ischemia may be reversible despite decreased ADC values. This correlates with the important clinical improvement that may occur after an initial major CVT-related neurologic deficit. Cerebral CT-Venography is emerging as a good alternative to MRI in the diagnosis of CVT, mostly because of its better availability, high spatial resolution and ease of interpretation. Our case illustrates the use of CT-Venography on the diagnosis of CVT. CT-Venography and MRI showed a correlation on the localization and extent of the thrombosis.

Differential Diagnosis List

Final Diagnosis

Subacute Dural Sinus Thrombosis

URL:	https://eurorad.org/case/6560
DOI:	10.1594/EURORAD/CASE.6560
ISSN:	1563-4086