Magnetic resonance imaging in lateral sinus hypoplasia and thrombosis

Lateral sinus thrombosis may be difficult to differentiate angiographically from lateral sinus hypoplasia, which mainly affects its proximal transverse portion. Using magnetic resonance imaging, we evaluated six patients who demonstrated poor filling or lack of filling of one or both lateral sinuses at angiography. In each patient, magnetic resonance imaging unambiguously demonstrated either lateral sinus thrombosis or lateral sinus hypoplasia. The latter was characterized by a frank asymmetry in size (surface of section) of the transverse portion of the lateral sinuses on parasagittal images without any abnormal signal in the course of the sinus. Lateral sinus thrombosis was indicated by increased intraluminal signal on all planes and with all pulse sequences. By virtue of its freedom from bone-related artifact, its multiplanar imaging capability, and its sensitivity to both blood flow and thrombus formation, magnetic resonance imaging is an excellent tool for the evaluation of lateral sinus thrombosis or hypoplasia.     

Importance of anatomical asymmetries of transverse sinuses: an MR venographic study

Time-of-flight (TOF) magnetic resonance venography (MRV) is often used to examine the intracranial dural sinuses, particularly in the evaluation of dural sinus thrombosis. The goal of the study was to evaluate the use of TOF MRV in assessing the normal anatomy of dural sinuses and their variations as sources of potential pitfalls in the diagnosis of venous sinus thrombosis. Cerebral TOF MRV obtained in 105 persons with normal MR studies were reviewed to determine the presence, aplasia and hypoplasia of the transverse sinuses. Twenty-one (20%) aplasias of the left sinus, 41 (39%) hypoplasia of the left sinus, 33 (31%) symmetric, 6 (6%) hypoplasia of the right sinus, and 4 (4%) aplasias of the right sinus cases were determined in the asymmetry in sizes of transverse sinuses. These results suggested that transverse sinus flow gaps or aplasias can be observed in approximately 24% of normal population on MR imaging. The rate of these gaps in normal subjects must be kept in mind because it can be a source of misdiagnosis in cases of suspected dural sinus thrombosis.     

Alexia without agraphia following cerebral venous thrombosis associated with protein C and protein S deficiency

A 26-year-old right handed female was admitted to hospital with right homonymous hemianopia associated with alexia without agraphia. Her cranial magnetic resonance imaging and magnetic resonance angiography revealed a left occipital venous infarction due to thrombosis of the left transverse, sigmoid sinuses and the left internal jugulary vein. The underlying conditions were protein C and protein S deficiency associated with the use of oral contraceptives. To our knowledge, alexia without agraphia has never been described due to a venous infarction associated with hereditary thrombophilia in the literature.     

Alexia without agraphia following cerebral venous thrombosis associated with protein C and protein S deficiency

A 26-year-old right handed female was admitted to hospital with right homonymous hemianopia associated with alexia without agraphia. Her cranial magnetic resonance imaging and magnetic resonance angiography revealed a left occipital venous infarction due to thrombosis of the left transverse, sigmoid sinuses and the left internal jugulary vein. The underlying conditions were protein C and protein S deficiency associated with the use of oral contraceptives. To our knowledge, alexia without agraphia has never been described due to a venous infarction associated with hereditary thrombophilia in the literature.     

Arachnoid granulations: a rare cause of lytic occipital bone lesion

Arachnoid granulation is often found incidentally in the dural sinuses and skull. It may also enlarge the dural sinus or inner table of the skull. We report a 46-year-old woman who presented with occipital headaches and arachnoid granulations in both transverse sinuses and torcular herophili. Neurological examination was normal. Fundoscopic examination, visual fields and acuity were normal. The headache resolved with medical treatment. No intervention for these lesions was planned. The patient was followed up with magnetic resonance imaging studies.     

Technical issues for MRI examination of the posterior fossa

Examination of the posterior fossa by magnetic resonance imaging is discussed with respect to modern techniques and equipment, and including recent results of non-conventional studies in multiple sclerosis. Optimal protocol design will maximize resolution and signal strength while providing diagnostic contrast. Motion artifact from the sigmoid and transverse sinuses may appear as ghosting and can be mitigated with proper imaging parameter choices.     

Arachnoid granulations in the transverse sinuses of a patient with ocular melanoma.

Arachnoid granulations show typical imaging features that allow their distinction from dural sinus thrombosis and intrasinus tumor. These features include a mid-lateral transverse sinus location, focality, common adjacent entering superficial veins, origin of attachment, low density on computed tomography (CT), isointensity-hypointensity on T1-weighted magnetic resonance imaging (MRI) and hyperintensity on T2-weighted MRI. We report the CT and MRI findings of incidentally detected bilateral arachnoid granulations in the transverse sinuses of a patient with ocular melanoma.     

Recanalisation of cerebral venous thrombosis

OBJECTIVE: To investigate recanalisation in the first 12 months after cerebral venous thrombosis. METHODS: 33 consecutive patients presenting with cerebral venous thrombosis were enrolled in the study. Diagnosis was made by magnetic resonance imaging (MRI) and magnetic resonance venography (MRV) or catheter angiography. Patients were initially treated with intravenous heparin. Warfarin was given for at least four months. Cerebral MRI and MRV were done at four months and repeated after 12 months if venous thrombosis persisted. Outcome was evaluated by the Rankin scale at 12 months. RESULTS: Outcome at 12 months was good, with a median modified Rankin scale score of 0 (range 0 to 2); 27 patients (82%) had no residual deficits. No patient suffered recurrent cerebral venous thrombosis, deep vein thrombosis, or pulmonary embolism during follow up. After four months, all deep cerebral veins and cavernous sinuses, 94% of superior sagittal sinuses, 80% of straight sinuses, 73% of jugular veins, 58% of transverse sinuses, and 41% of sigmoid sinuses had recanalised. No further recanalisation was observed thereafter. CONCLUSIONS: The results suggest that recanalisation only occurs within the first four months following cerebral venous thrombosis and not thereafter, irrespective of oral anticoagulation.     

Venous Infarction of Brainstem and Cerebellum

The authors describe 2 cases of posterior fosa venous infarction. A 56-year-old woman with essential thrombocytemia presented with fluctuating complaints of headache, nausea, vomiting, left-sided numbness-weakness, and dizziness and became progressively stuporous. Cranial magnetic resonance imaging (MRI) showed bilateral parasagittal fronto-parietal and left cerebellar contrast-enhancing hemorrhagic lesions. On magnetic resonance venography, the left transverse and sigmoid sinuses were occluded. The second patient, a 39-year-old woman, presented with acute onset of diplopia, numbness of the tongue, vertigo, and right-sided weakness following a gestational age stillbirth. MRI revealed lesions in the right half of midbrain and pons and in the superior part of the right cerebellar hemisphere. Digital subtraction angiography showed right transverse and sigmoid sinus occlusion. The authors suggest that one should investigate the possibility of venous infarction in the presence of posterior fossa lesions that are often hemorrhagic and are not within any arterial territory distribution but respect a known venous drainage pattern. Recognition of the observed clinical and neuroimaging features can lead to earlier diagnosis and, potentially, more effective management.     

Cerebral MR venography of transverse sinuses in subjects with normal CSF pressure

Flow artifacts or anatomic variants of venous sinuses often make MR venography (MRV) interpretation difficult. The authors investigated cerebral MRV in 111 subjects with normal CSF pressure to identify the most common flow abnormalities of transverse sinuses (TS). Disturbance of venous outflow in one transverse sinus was commonly observed in 30% of subjects whereas flow abnormalities of both TS occurred in 2 of 111 individuals. Subjects with flow gaps in both TS should undergo lumbar puncture to exclude increased CSF pressure.     

Alterations in the intracranial venous sinuses in spontaneous nontraumatic chronic subdural hematomas

Occlusion of the cerebral venous system is frequently associated with intraparenchymal or subarachnoid hemorrhage. There are few reports of cerebral venous thrombosis associated with nontraumatic chronic subdural hematoma (CSH). We aimed to evaluate the intracranial venous system in patients with spontaneous nontraumatic CSH and to identify alterations in their venous sinuses. In this study, eight patients with spontaneous, nontraumatic CSH were followed for a 7-year period (mean: 2.2 years, range: 1–7 years). Neuroradiological images were taken at the onset of symptoms and during follow-up. Venous angiography or magnetic resonance venography was used to evaluate the cerebral venous system of patients. In all patients, medical or surgical treatments were based on clinical symptoms. In seven of the eight patients, the CSH was in the left hemisphere, whereas one patient had bilateral CSH. In one of the eight patients, thrombosis of the transverse sinus and sigmoid sinus was found, but recanalization was observed at follow-up. In a further three patients, the superior sagittal sinus, the straight sinus, and the vein of Galen were markedly reduced in diameter compared to normal or were not visible at presentation, but normal flow was observed at follow-up. In the remaining four patients, the transverse sinus was not observed at symptom onset or during long-term follow-up. A nontraumatic CSH can occur secondary to a venous thrombosis or it can be associated with the inability to image some of the venous sinuses. Venous flow was restored at long-term follow-up. Increased intravenous pressure is thought to be the pathogenic factor that causes a nontraumatic CSH.     

Muscle imaging in clinical practice: diagnostic value of muscle magnetic resonance imaging in inherited neuromuscular disorders

PURPOSE OF REVIEW: This review reports on the use of muscle magnetic resonance imaging as a clinical and research tool in inherited neuromuscular disorders. RECENT FINDINGS: Several papers published during the past few years have reported on the value of muscle magnetic resonance imaging in detecting patterns of muscle involvement in various muscular dystrophies and other inherited myopathies. The patterns of muscle involvement observed on muscle magnetic resonance imaging are often specific for distinct genetic entities. SUMMARY: Our review of the literature suggests that muscle magnetic resonance imaging can provide information that is useful in clinical practice and may be used as an additional tool in a diagnostic flow chart to select appropriate genetic and biochemical investigations.     

Cerebral venous thrombosis in a gentleman presenting with fever, convulsion and frontotemporal haemorrhages.

Cerebral venous thrombosis (CVT) is an uncommon but serious type of stroke. Thrombosis may involve the cortical or deep veins or the venous sinuses. The presenting clinical features are non-specific. We report a 48-year-old man with CVT who presented with fever, bitemporal throbbing headache, and generalised convulsion. Computed tomography (CT) of the brain revealed acute haemorrhages over right anterior frontal and posterior temporal regions with surrounding oedema and right anterior temporal subcortical oedema. The initial diagnosis was herpes simplex encephalitis. Absence of venous flow over the right transverse and sigmoid sinuses during the venous phase of digital subtraction angiography (DSA) revealed CVT. He was anti-coagulated for 6 months. An underlying cause of CVT was not detected. A high index of suspicion is required when risk factors of CVT are present. CT brain may be normal or showing non-specific findings. Magnetic resonance imaging plus venography, CT venography, or DSA is diagnostic.     

Cerebral venous thrombosis presenting with subarachnoid hemorrhage after spinal anesthesia

A 22-year-old male had a meniscopathy operation using spinal anesthesia. After the operation, the patient reported a throbbing headache. His brain computed tomography (CT) showed subarachnoid hemorrhage (SAH) and hyperdense dural venous sinuses suspicious for thrombosis. Filling defects were observed in the superior sagittal and right transverse sinuses on the contrast-enhanced magnetic resonance images. The patient was diagnosed with cerebral venous sinus thrombosis (CVST). On the tenth day of his admission, his clinical findings progressed and heparin therapy was initiated after resorption of hemorrhage was observed in a second non-contrast CT scan. The patient developed decreased consciousness the day after heparin administration. A subsequent brain CT revealed intraparenchymal hemorrhage in the right anteroinferior frontal region. Heparin therapy was discontinued, and anti-edema therapy was started. The presentation of CVST with SAH is a rare condition. Furthermore, development of CVST after spinal anesthesia is very rare. In this case, CVST developed after spinal anesthesia, and its first clinical presentation was SAH. To our knowledge, this is the first case CVST presenting with SAH after spinal anesthesia.     

Anomalous PiB enhancement in the superior sagittal and transverse venous sinuses

Pittsburgh compound-B (PiB), an amyloid-binding positron emission tomography (PET) tracer, is widely used for imaging amyloid-β in those with and at risk for Alzheimer disease. Here, we report on an otherwise normal 68-year-old female with abnormally high and very focal PiB retention. Coregistered T1-weighted magnetic resonance imaging and dynamic 2-fluoro-2-deoxy-D-glucose (FDG) images confirmed that the focal PiB enhancement was in the superior sagittal and transverse sinuses, outside of the adjacent cortex. Flow through the venous vasculature was normal as assessed by dynamic FDG PET imaging. These features supported the conclusion that PiB retention was not simply due to a hemodynamic abnormality, but may have represented PiB binding to fibrillar deposits of a β-sheet protein (ie, amyloid), whose nature is currently unclear.     

Elevated intracranial pressure associated with idiopathic retinal vasculitis, aneurysms, and neuroretinitis syndrome.

The idiopathic retinal vasculitis, aneurysms, and neuroretinitis (IRVAN) syndrome typically occurs in young patients and may produce multiple retinal macroaneurysms, neuroretinitis, and peripheral capillary nonperfusion. Optic disc edema has been described, but elevated intracranial pressure has not been previously documented. We report a case of a 12-year-old girl who presented with bilateral disc swelling and peripapillary hemorrhage. Brain magnetic resonance imaging (MRI) was normal, but lumbar puncture yielded an opening pressure of 360 mm H2O with normal constituents. Fluorescein angiography delineated saccular aneurysms of the retinal arteriolar vasculature, and IRVAN syndrome was diagnosed. MR venography disclosed poor filling of both transverse venous sinuses. Acetazolamide treatment of 14 months did not alter the fundus findings. IRVAN syndrome may present initially with optic nerve swelling and elevated intracranial pressure with subsequent development of the characteristic retinal vascular abnormalities.     

Cerebrovascular abnormalities in pediatric stroke: assessment using parenchymal and angiographic magnetic resonance imaging

Three-dimensional (volume) magnetic resonance angiography is a noninvasive technique that images the intracranial and cervical arterial vasculature without contrast agents. Twenty-four children with strokes had combined parenchymal magnetic resonance imaging and magnetic resonance angiography 1 day to 4 years after acute presentation. Eight had had prior intra-arterial angiography. Eighteen magnetic resonance angiographic studies showed arterial stenosis or occlusion in the vascular distribution of magnetic resonance image-defined brain infarction and, in 7 children, in the same location as previously defined abnormalities on intra-arterial angiography. One child had a normal intra-arterial angiogram and magnetic resonance angiogram. The other 5 children with normal magnetic resonance angiographic studies included 3 with presumed embolic disease, 1 with meningitis, and 1 with Crohn's disease-related vasculitis. Collateral flow patterns could be determined in 4 children. Artifact presenting as filling defects in vessels was present in 10 studies, but did not interfere with interpretation of 8 studies. Combined magnetic resonance imaging/magnetic resonance angiography provides a screening technique to evaluate noninvasively brain parenchyma and vasculature in children with suspected large-vessel abnormalities, allowing selection for intra-arterial angiography and serial monitoring of vascular abnormalities over time and during therapeutic intervention.     

Dural sinus thrombosis following head injury: report of two cases and review of the literature

Dural sinus thrombosis (DST) usually involves the sagittal, transverse and sigmoid sinuses and is more common in women due to pregnancy, puerperium and oral contraceptive use. Other etiologies include coagulopathies, infection and head injury. We have present two DST cases following head injury. The first case was a 35-year-old man hospitalized because of one-week history of headache and repeated vomiting after a mild head injury. Thrombosis of the superior sagittal sinus, right transverse and sigmoid sinuses and right jugular vein was determined on angiography. The second case was a 25- year-old man operated on for epidural hematoma at the posterior fossa. Meningitis developed and an abducens palsy was determined. Magnetic resonance imaging demonstrated thrombosis of the right transverse and sigmoid sinus. Low molecular weight heparin was administrated for three months. Both cases had good recovery, but one had recanalisation of the thrombosis. Intracranial hematomas, depressed skull fracture or skull fracture that cross the sinus can obstruct the blood flow in the sinus. Moreover, closed head injury may cause to DST. Because of undefinitive pathophysiology, a consensus was not obtained on overall strategy concerning conservative, radiosurgical, or surgical therapy yet.     

Flow quantification in the superior sagittal sinus using magnetic resonance

To date, the intracerebral veins and venous sinuses have not been amenable to noninvasive study. We describe a magnetic resonance (MR) technique using "bolus tracking" for rapid imaging and measurement of cerebral venous flow. We specifically applied the technique to the superior sagittal sinus, but it can be used for evaluation of other cerebral venous structures. In 10 healthy subjects and 21 patients referred for MR brain studies, mean flow was 420 ml/min. There was a significant inverse correlation between blood flow and age. There were dynamic changes in cerebral blood flow (CBF) during hyperventilation and hypercapnia. Since the cerebral cortex drains almost exclusively to the superior sagittal sinus, these flow measurements represent an index of global CBF. MR flow quantification provides a new means for assessing dynamic changes in CBF, and may prove useful for monitoring the effects of various disease processes and pharmaceutical agents on CBF.     

Cerebral venous thrombosis in systemic lupus erythematosus

We describe six cases of cerebral venous thrombosis in patients with systemic lupus erythematosus. In one patient, cerebral venous thrombosis was the initial manifestation of lupus; in the five others, it occurred 1-33 years after the diagnosis of lupus. The main clinical features of cerebral venous thrombosis were persistent headache in all six patients, focal symptoms in four, and seizures in three; papilledema was present in only one patient. Cerebral venous thrombosis was diagnosed based on angiography or magnetic resonance imaging. Both the transverse (in five patients) and the superior sagittal (in three) sinuses were involved. Extracranial arterial and/or venous thrombosis were present in three patients, abortion in two, thrombocytopenia in four, and lupus anticoagulant in three. The neurologic symptoms resolved rapidly in five patients treated with steroids and heparin. Cerebral venous thrombosis should be suspected in patients with lupus who complain of persistent headache, especially in the presence of neurologic symptoms.