Imaging of cerebral venous thrombosis: current techniques, spectrum of findings, and diagnostic pitfalls

Interobserver variability in the detection of cerebral venous thrombosis using CT venography with matched mask bone elimination

OBJECTIVES

Computed tomography venography (CTV) has proven to be a reliable imaging method in the evaluation of cerebral venous thrombosis with good correlation to magnetic resonance (MR) imaging and digital subtraction angiography (DSA). It is fast and widely accessible, especially in the emergency setting. For better visualization of vascular structures bone is often removed from the images. The purpose of this study was to evaluate the quality of a fully automatic bone removal method, matched mask bone elimination (MMBE), and to assess the interobserver variability of the CTV technique.

PATIENTS AND METHODS

Fifty patients with clinical suspicion of cerebral venous thrombosis underwent multislice CTV with MMBE post-processing. Axial source images and maximum intensity projections were retrospectively evaluated by two neuroradiologists for quality of bone removal and for the presence or absence of thrombosis in nine dural sinuses and five deep cerebral veins. A per sinus/vein and a per patient analysis (thrombosis in at least one sinus or vein) was performed and interobserver agreement was assessed.

RESULTS

Both observers considered bone removal good in all patients (100%). Interobserver agreement per patient was excellent (kappa=0.83), with a full agreement in 47 of 50 patients (94%). The interobserver agreement per sinus or vein was good (kappa=0.76), with a full agreement in 679 of 700 sinuses or veins (97%).

CONCLUSION

CTV aided with MMBE is a robust technique for visualization of the intracranial venous circulation, removing bone effectively. CTV has high interobserver agreement for presence or absence of cerebral venous thrombosis.

Decompressive surgery in malignant dural sinus thrombosis: report of 3 cases and review of the literature

Cerebral venous and dural sinus thrombosis (CVDST) is a rare cause of stroke in young and middle-aged adults. When the clinical course is complicated by uncontrollable intracranial hypertension and brainstem compression due to edema or cerebral hemorrhage, the prognosis is poor. The authors evaluated the therapeutic role of surgical decompression in patients with clinical signs of impending herniation. Cerebral venous and dural sinus thrombosis complicated by impending brain herniation a very rare, life-threatening but potentially treatable clinical condition.

Three patients with pupillary signs of transtentorial herniation due to brain edema and hemorrhage caused by CVDST (superior sagittal sinus in 1 patient and transverse and sigmoid sinus in 2 patients) were treated surgically. The intervention consisted of clot removal, infarcted tissue resection, and frontotemporoparietooccipital craniectomy with duraplasty. According to the Glasgow Outcome Scale, 2 patients were classified as having good recovery and 1, moderate disability. The results of neuropsychological assessment were normal in 2 patients and demonstrated a partial neuropsychological deficit (neglect) in the other.

Surgery may be indicated in selected patients with CVDST whose condition is deteriorating because of intractable intracranial hypertension and impending brain herniation.

CT Diagnosis of Cerebral Venous Thrombosis: Importance of the First Examination for Fast Treatment

This study is a retrospective investigation of the role of non contrast-enhanced CT (NCCT) in the diagnosis of cerebral venous thrombosis (CVT) in clinical practice. We retrospectively identified 24 patients discharged with a diagnosis of CVT between January 2002 and December 2008 who had undergone NCCT as the first imaging modality. NCCT had been evaluated by a general radiologist and subsequently by a neuroradiologist in five cases. Final diagnosis was established by CT angiography (CTA), magnetic resonance (MR) and digital subtraction angiography (DSA). NCCT diagnosis was defined as "positive" when the neuroradiologist suggested the diagnosis of CVT on the report, as opposed to the "negative" diagnosis group. All NCCT examinations were reviewed by a neuroradiologist experienced in cerebrovascular pathology. We compared his evaluation and analysed the location and number of direct signs found on NCCT. The neuroradiologist strongly suggested an NCCT diagnosis of CVT in 63% (15/24) of patients: 80% (4/5) with deep venous thrombosis (DVT) and 57% (11/19) with sinus venous thrombosis (SVT). The general radiologist's NCCT evaluation was incorrect in four cases, subsequently diagnosed at NCCT by the neuroradiologist. After reviewing the NCCT examination the experienced neuroradiologist identified the CVT direct sign in two that belonged to the NCCT negative diagnosis group. Thus the direct sign was present in 71% (17/24) of the cases: all the patients with DVT and 63% (12/19) of the patients with SVT. NCCT still plays an important role for fast and accurate diagnosis of CVT in the emergency setting. NCCT displayed the CVT direct sign more frequently than previously thought and it was correctly interpreted in most cases. Neuroradiological consultation adds value to the general radiologist's evaluation.

Noncontrast CT in deep cerebral venous thrombosis and sinus thrombosis: comparison of its diagnostic value for both entities

BACKGROUND AND PURPOSE

With its highly variable clinical presentation, the diagnosis of cerebral venous sinus thrombosis (SVT), and especially of deep venous thrombosis (DVT), as rare but important causes of stroke is challenging. Because noncontrast cranial CT (NCCT) is still the imaging technique of choice in most emergency departments, we aimed to investigate its value in the diagnosis of SVT and DVT.

MATERIALS AND METHODS

Screening our patient data base, we identified 8 patients with DVT and 25 patients with SVT. We also included a control group of 36 patients who had presented with clinical signs of DVT or SVT but in whom thrombosis was subsequently excluded. MR imaging, multidetector row CT angiography (MDCTA), and/or digital subtraction angiography (DSA) were used as the reference standard. Three independent readers assessed the NCCTs for the presence of direct and indirect signs of DVT or SVT. Direct signs included the presence of hyperattenuated sinuses (ie, cord sign) or veins (ie, attenuated vein sign), whereas parenchymal edema and hemorrhage were indirect signs.

RESULTS

The sensitivity and specificity of the attenuated vein sign for the diagnosis of DVT were 100%, and 99.4%, respectively, whereas the sensitivity and specificity of the cord sign for SVT were 64.6% and 97.2%, respectively. The sensitivity and specificity values of NCCT were 93.7% and 98% for intracerebral edema and 94.8% and 98.7% for intracerebral hemorrhages, respectively.

CONCLUSIONS

Although NCCT is insufficient to exclude a SVT, its value in the emergency diagnosis of DVT seems to be very high.

Brain lesions in cerebral venous sinus thrombosis

BACKGROUND AND PURPOSE

Analyze the relationship between the location and extent of sinus thrombosis and presence and severity of brain lesions.

METHODS

Retrospective chart and neuroimaging review of patients with documented CVST. A CVST score was devised to quantify the extent of cerebral venous sinus thrombosis.

RESULTS

Nineteen of 56 (34%) patients had brain lesions. The extent of sinus thrombus was associated with increased risk of brain lesions (CVST score 1.9 among patients without brain lesions versus 3.1 in those with lesions; P=0.006). Age, sex, and acquired or hereditary thrombophilias were not associated with the risk of parenchymal lesions. Functional outcomes were favorable even in patients with extensive CVST and parenchymal lesions at presentation.

CONCLUSIONS

The extent of the sinus involvement correlates with the risk of brain lesions in patients with CVST, but additional factors might also contribute to their occurrence.

Imaging for neuro-ophthalmic and orbital disease - a review

A literature review was performed by content experts in neuro-ophthalmology and neuroradiology using a systematic English-language Medline search (1994-2008) limited to articles with relevance to neuro-ophthalmic and orbital imaging. The information covered in this review includes: (i) the basic mechanics, indications and contraindications for cranial and orbital computed tomography and magnetic resonance (MR) imaging; (ii) the utility and indications for intravenous contrast, (iii) the use of specific MR sequences; (iv) the techniques and ophthalmic indications for computed tomography/MR angiography and venography; and (v) the techniques and indications for functional MR imaging, positron emission tomography scanning and single photon emission computed tomography. Throughout the review accurate and timely communication with the neuroradiologist regarding the clinical findings and suspected location of lesions is emphasized so as to optimize the ordering and interpretation of imaging studies for the ophthalmologist.

A series of patients with subpial hemorrhage: clinical manifestation, neuroradiological presentation and therapeutic implications

Subpial hemorrhage is a rare finding in patients with a variable spectrum of neurological symptoms and signs. Here we present a series of 10 patients with subpial hemorrhage, 53 to 80 years old, diagnosed and treated within the last 4 years at a single center. Patients were identified based on imaging criteria with either magnetic resonance imaging (MRI) or computed tomography (CT) showing blood along the cortical surface. Presenting symptoms were diverse, with seizures being the most frequent followed by headaches and focal neurological signs such as sensory or motor deficits. Of 7 patients undergoing lumbar puncture, none showed fresh blood or cerebrospinal fluid (CSF) xanthochromia. Neither digital subtraction angiography (DSA) nor MR venography (MRV) confirmed cerebral vein thrombosis as a possible etiologic factor for subpial hemorrhage. Patients for whom follow-up was available (n=8), showed complete recovery indicating an excellent prognosis. Overall, the etiology of subpial hemorrhage remains obscure. Treatment should be symptomatic with particular attention to antiepileptic medication.

Large arachnoid granulations involving the dorsal superior sagittal sinus: findings on MR imaging and MR venography

BACKGROUND AND PURPOSE

Large arachnoid granulations (AG) within the dorsal superior sagittal sinus (SSS) have been incompletely characterized and can be confused with pathology. This report reviews the characteristics of these anatomic structures to establish common imaging features that allow differentiation from pathology.

MATERIALS AND METHODS

Twelve cases of large AG in the dorsal SSS are presented, identified by MR imaging. Signal intensity characteristics, size, location, venographic appearance, and association with adjacent venous and osseous structures were documented.

RESULTS

A defect in the dura of the SSS was seen in all of the cases communicating with the subjacent subarachnoid space. The average size of the AG was 8.1 x 9.4 x 10.0 mm (range, 4-19 mm). Ten produced calvarial remodeling, and 11 were in the direct vicinity of the lambda. On T2-weighted images, all were hyperintense to the brain. On T1-weighted images, 8 were hypointense and 4 were hypointense with mixed areas of isointense signal intensity. All of the AGs were associated with cortical venous structures entering the sinus. On MR venography, AGs appeared as focal protrusions into the sinus, displacing, distorting, and narrowing the sinus lumen. Seven patients had headache without other visible cause on MR imaging, and 4 were initially interpreted as thrombosis or tumor.

CONCLUSION

Large AGs can occur in the dorsal SSS. They are well-defined projections of the subarachnoid space into the sinus, can cause luminal narrowing and calvarial remodeling, and have typical signal intensity characteristics, position, and morphology differentiating them from other pathology. Association with patient symptoms is uncertain.

[Bilateral papilledema: prospective study of fifty patients]

In this prospective study, we report fifty consecutive cases of bilateral papilledema without neurosurgical or obvious ophthalmologic etiology, referred to our institution between January 2005 and March 2007. Lumbar puncture with opening CSF pressure measurement distinguished two groups of patients: Group 1 (n=39) with and Group 2 (n=11) without intracranial hypertension. In Group 1, 9/39 patients presented secondary intracranial hypertension mainly due to cerebral venous thrombosis. In 30 patients, after complete investigations, a diagnosis of idiopathic intracranial hypertension was made: as commonly reported, patients were predominantly overweight (96.7% with body mass index>25kg/m2) young (mean age=27.6 years) and women (96.7%). Eleven patients with intracranial hypertension had no headaches. In Group 2, the most common diagnosis was bilateral non-arteritic anterior ischemic optic neuropathy, but rare causes have been identified.

Successful management of an extensive intracranial sinus thrombosis in a patient undergoing IVF: case report and review of literature

OBJECTIVE

To report a successfully managed case of extensive intracranial sinus thrombosis that occurred during an IVF cycle, and to review the literature.

DESIGN

Case report and review of literature.

SETTING

University-affiliated teaching hospital.

PATIENT(S)

A 38-year-old nulliparous woman who developed severe ovarian hyperstimulation syndrome on luteal day (LD) 5 during an IVF cycle. Hemoconcentration was corrected, ascitis drained, and heparin prophylaxis started. On LD7, the patient complained of severe headache and neck pain. A magnetic resonance imaging (MRI) study of the head showed extensive cortical vein and dural sinus thrombosis, including the superior sagittal sinus and transverse sinuses.

INTERVENTION(S)

The patient was fully heparinized using low-molecular-weight heparin. On LD15 she was discharged home on warfarin, after confirming a negative pregnancy test. Complete thrombophilia work-up was negative.

MAIN OUTCOME MEASURE(S)

Clinical outcome.

RESULT(S)

Repeat MRI 2 months later revealed patent superior sagittal sinus and transverse sinuses, unremarkable cortical veins, and no evidence of flow obstruction. The patient was asymptomatic, with no neurologic sequelae.

CONCLUSION(S)

Extensive intracranial sinus thrombosis in women undergoing IVF may present with minimal symptoms and can occur in the absence of pregnancy and thrombophilia and despite heparin prophylaxis and correction of hemoconcentration. Medical management was successful and left the patient with no neurologic sequelae.