Endovascular treatment for acute basilar thrombosis via a transradial approach: Initial experience and future considerations

Acute basilar artery occlusion (BAO) secondary to emergent large vessel occlusion (ELVO) has an extremely poor natural history, with a reported mortality rate up to 95%. Mechanical thrombectomy in the setting of ELVO is generally performed via a transfemoral approach. However, radial access is increasingly being utilized as an alternative. We report our initial multi-institutional experience using primary radial access in the treatment of acute BAO in nine consecutive cases. Technical success defined as a TICI score of 2B or 3 was achieved in 89% of cases. Average puncture to revascularization time was 35.8 minutes. There were no complications related to radial artery catheterization. We contend radial access should potentially be considered as the first-line approach given inherent advantages over femoral access for mechanical thrombectomy for BAO.

Carotid cavernous fistula associated with persistent trigeminal artery: endovascular treatment using coil embolization

Carotid-cavernous fistula (CCF) associated with persistent trigeminal artery (PTA) is a rare but important clinical entity. We present a case treated by microcoil embolization with preservation of internal carotid, PTA, and hasilar artery flow following embolization. A 62-year-old female developed pulsatile tinnitus followed by left eye proptosis and diplopia. Examination revealed a cranial nerve VI palsy and an objective bruit over the left orbit. Angiographic evaluation revealed a carotid cavernous fistula originating from a persistent trigeminal artery. Placement of a detachable balloon across the fistula site while preserving the PTA proved impossible, and the fistula was treated with microcoils following placement of a microcatheter across the fistula into the cavernous sinus. Complete closure of the fistula was followed by resolution of the patient's symptoms. Preservation of all major vessels including the PTA was accomplished through the use of coil embolization. Careful evaluation of the angiogram is necessary to identify PTA associated with a CCF. Previous reports have described treatment of CCF with PTA by surgical or balloon ocolusion, some involving sacrifice of the PTA. Examination of the relevant embryology and anatomy reveals, however, that occlusion of the PTA must be approached with caution due to potential supply to the posterior circulation.

Dural arteriovenous fistulas of the craniocervical junction

Dural arteriovenous fistulas (DAVF) involving the craniocervical junction are uncommon lesions that may result in neurological deficits referable to posterior fossa structures and/or the spinal cord. We report on two patients with craniocervical junction DAVF whose venous drainage involved the cervical spinal cord. Both cases presented with progressive quadriparesis and parenchymal magnetic resonance signal abnormality of the cervical spinal cord. Both patients improved following embolization of the fistulas. AVF of the craniocervical junction are an uncommon, but important cause of treatable neurological deficits referable to this region of the nervous system.

Angiographic assessment of the transverse sinus and vein of labbé to avoid complications in skull base surgery

Advances in the field of skull base surgery have dramatically reduced the mortality and morbidity of operations on the skull base. Nevertheless, cerebral ischemic events from compromised blood supply to areas of the brain still occur. Although arterial compromise is responsible for a majority of these events, the venous side of the circulation can also play a role in producing cerebral infarctions. A key area of cerebral venous drainage is at the junction of the transverse sinus, sigmoid sinus, and vein of Labbé. Absence of the transverse sinus with the outflow of the vein of Labbé limited to the sigmoid sinus puts these patients at an increased risk for venous infarcts when this area is manipulated during skull base surgery. We have studied 100 consecutive carotid angiograms performed on 50 individuals for carotid artery disease or to rule out aneurysms. We have found that 16.7% of individuals have one atretic transverse sinus. We discuss our results and the implications that they have in skull base surgery. It is our hope that a better understanding of the cerebral venous drainage patterns will help skull base surgeons avoid complications in the future.

Arteriovenous shunt visualization in arteriovenous malformations with arterial spin-labeling MR imaging

BACKGROUND AND PURPOSE

A reliable quantitative technique for measuring arteriovenous (AV) shunt in vascular malformations is not currently available. Here, we evaluated the hypothesis that continuous arterial spin-labeled (CASL) perfusion MR imaging can be used to detect and measure AV shunt in patients with arteriovenous malformations (AVMs).

MATERIALS AND METHODS

CASL perfusion MR imaging was performed in 7 patients with AVMs. Semiquantitative AV shunt estimates were generated based on a thresholding strategy by using signal-intensity difference (DeltaM) images to avoid potential errors in cerebral blood flow (CBF) calculation related to abnormal transit times and nonphysiologic blood-tissue water exchange in and around the AVMs. The potential for measuring CBF in regions distant from and near the AVM was explored, as was the relationship of CBF changes related to the size of the shunt.

RESULTS

In all 7 cases, striking increased intensity was seen on CASL perfusion DeltaM maps in the nidus and venous structures draining the AVM. Shunt estimates ranged from 30% to 0.6%. Mean CBF measurements in structures near the AVMs were not significantly different from the contralateral measurements. However, CBF in adjacent ipsilateral white matter increased relative to the contralateral side as the percent shunt increased (P = .02). Cortical gray matter CBF Delta (contralateral-ipsilateral) values demonstrated the same effect, but the correlation was weak and not significant. Thalamic CBF decreased ipsilaterally with increasing percent AV shunt (P = .01), indicating a possible steal effect. Basal ganglia Delta values showed little change in CBF with the size of the AV shunt.

CONCLUSION

CASL perfusion MR imaging can demonstrate AV shunting, providing high lesion conspicuity and a novel means for evaluating AVM physiology.

Posttraumatic carotid-cavernous sinus fistula

BACKGROUND AND OBJECTIVES

Posttraumatic carotid-cavernous sinus fistula is a rare complication of maxillofacial trauma and is seldom discussed in the literature. Motor vehicle accidents, falls, and other crush injuries contribute to the incidence of basilar skull fractures and the formation of fistulae. When injuries occur in the vessel wall, the carotid artery has the potential to fill the low-pressure cavernous sinus. The symptoms include chemosis, proptosis, pulsating exophthalmos, diplopia, ophthalmoplegia, orbital pain, audible bruits, and blindness.

METHODS AND MATERIALS

The conventional treatments include carotid ligation and embolization. These techniques have often proved to be ineffective. A new method--the occlusive balloon technique--has been developed and is described in this article. A clinical case is used to illustrate the procedure.

RESULTS AND/OR CONCLUSIONS

Utilization of balloon catheters provides a minimally invasive technique to treat patients, without significant morbidity or mortality. The procedure is found to be successful and predictable.

Development of a posterior cerebral artery aneurysm subsequent to occlusion of the contralateral internal carotid artery for giant cavernous aneurysm

We report a case of a patient who developed a left posterior cerebral artery aneurysm 5 years after balloon occlusion of the right internal carotid artery for a giant cavernous aneurysm. The location of the new aneurysm was outside of the primary collateral pathways to the contralateral, proximally occluded, anterior circulation, illustrating the complexity of hemodynamic factors contributing to the development of intracranial saccular aneurysms. The appearance of an aneurysm in this setting supports the hypothesis that degenerative factors and hemodynamic stresses are important in the etiology of intracranial aneurysms.

Fatal rebleeding following coil embolization of cerebral aneurysms: the role of long-term systemic anticoagulation

Embolization of cerebral aneurysms has become a common technique. Its impact on subsequent medical management of the patient is not well known. We report two patients who presented in a poor neurological grade after subarachnoid hemorrhage from posterior communicating artery aneurysms. Both were treated by coil embolization and both developed subclavian vein thrombosis, requiring systemic anticoagulation, initiated 11 and 21 days after embolization, respectively. Both developed a large, fatal intracranial hemorrhage adjacent to the embolized aneurysm in the fourth week of anticoagulation. Systemic anticoagulation of patients who have had a ruptured aneurysm treated by coil embolization may carry a significant risk of rebleeding. Alternate management strategies should be considered in these patients.

Mycotic aneurysm and cerebral infarction resulting from fungal sinusitis: imaging and pathologic correlation

SUMMARY

A 73-year-old man was admitted with invasive aspergillus of the sphenoid sinus. Endoscopic debridement of the sphenoid sinus was complicated by rupture of a mycotic cavernous carotid artery aneurysm with severe epistaxis. The aneurysm was closed emergently by endovascular coil placement. Subsequently, the mycotic aneurysm extended intradurally and caused fatal subarachnoid hemorrhage. The radiologic-pathologic data illustrate the mechanism of fungal mycotic aneurysm formation and growth. This case emphasizes the need for rapid diagnosis of potential fungal involvement of the central nervous system and suggests the necessity for aggressive treatment once fungal cerebrovascular involvement is identified.

Extracranial aneurysms of the posterior inferior cerebellar artery

OBJECTIVE

Extracranial aneurysms of the distal posterior inferior cerebellar artery (PICA) are extremely rare and sometimes difficult to diagnose without an adequate angiogram. We present the first series of 3 patients who were evaluated by the senior author and treated surgically.

METHODS AND RESULTS

All 3 patients presented with subarachnoid hemorrhage (SAH). Clincial symptoms, included occipital headache, nuchal rigidity, abducens nerve palsy and rapid neurologic deterioration. A unilateral injection of the vertebral artery failed to show the distal contralateral PICA and the aneurysm in 1 patient. All patients underwent aneurysm clipping through a posterior fossa craniectomy and C-1 laminectomy. The aneurysms were located on the tonsillomedullary segment of the PICA, 10-12 mm below the level of the foramen magnum.

CONCLUSIONS

It is important to adequately visualize the distal extent of both PICAs or these aneurysms may not be seen. Patients who present with SAH must have the entirety of both vertebral arteries evaluated to avoid missing these aneurysms. The aneurysms were located adjacent to the atlas necessitating an upper cervical laminectomy for adequate surgical exposure. In general, the patients did well postoperatively and none of the patients developed cerebral vasospasm.

Topic review: surface modifications enhancing biological activity of guglielmi detachable coils in treating intracranial aneurysms

BACKGROUND

Endovascular therapy with Guglielmi detachable coils is an accepted treatment option for patients with intracranial aneurysms. However, an emerging technology in the realm of endovascular tools is the use of traditional Guglielmi detachable coils with biologically active substances complexed to the coil surface to enhance aneurysm occlusion.

METHODS

We review the literature and current trends in modified Guglielmi detachable coils. Surface modifications with extracellular matrix proteins, growth factors, ion impregnation, and genetically altered cells have been used in animal studies to improve the cellular response of Guglielmi detachable coils. Similarly, coronary artery stents have been modified in several different ways to maintain vessel patency, contrary to the goal of endovascular therapy. We comparatively reviewed this literature to add insight into the evolution of the research on modified Guglielmi detachable coils.

CONCLUSIONS

Guglielmi detachable coil modifications have the potential to enhance aneurysm obliteration with directed cellular responses. This may allow aneurysm occlusion with coils in less time than untreated coils, thus decreasing the risks of aneurysm enlargement and hemorrhage.

Orbital drainage from cerebral arteriovenous malformations

OBJECTIVE

To describe the neuro-ophthalmic findings in patients with orbital drainage from cerebral arteriovenous malformations (AVMs).

METHODS

We reviewed the records of 100 consecutive adult patients with cerebral AVMs who presented to our institution during a 4-year period. All patients with orbital drainage were identified, and their neuro-ophthalmic evaluations were reviewed.

RESULTS

Three patients (3%) were identified with orbital drainage from a cerebral AVM. The first patient presented with typical chiasmal syndrome (reduced visual acuity, bitemporal hemianopia, and optic atrophy). Magnetic resonance imaging demonstrated a large left temporal and parietal lobe AVM with compression of the chiasm between a large pituitary gland and a markedly enlarged carotid artery. The second patient presented with headaches and postural monocular transient visual obscurations. Examination revealed normal visual function with minimal orbital congestion and asymmetrical disc edema, which was worse in the left eye. Magnetic resonance imaging revealed a large right parietal and occipital lobe AVM without mass effect or hemorrhage and an enlarged left superior ophthalmic vein. The third patient had no visual symptoms and a normal neuro-ophthalmic examination; a right parietal lobe AVM was discovered during an examination for the cause of headaches.

CONCLUSION

Orbital drainage from cerebral AVMs is rare. Manifestations may include anterior visual pathway compression, dilated conjunctival veins, orbital congestion, and asymmetrical disc swelling.

Peripheral spinal cord hypointensity on T2-weighted MR images: a reliable imaging sign of venous hypertensive myelopathy

BACKGROUND AND PURPOSE

MR findings reported in conjunction with spinal dural arteriovenous fistula (SDAVF) include cord swelling, increased T2 signal within the spinal cord, and parenchymal enhancement, each of which is nonspecific. Enlarged vessels on the cord surface, the most specific MR finding, is noted in only half of SDAVF patients. Nevertheless, we have frequently observed MR peripheral hypointensity of the spinal cord in SDAVF on T2-weighted images, which is not characteristic of nonvascular or nonhemorrhagic causes of myelopathy and which has not been described in association with SDAVF. We hypothesized that peripheral cord hypointensity might reliably suggest the diagnosis of SDAVF or other causes of venous hypertensive myelopathy.

METHODS

We reviewed the MR findings in 11 consecutive cases of angiographically confirmed symptomatic SDAVF and in four cases of intracranial dural arteriovenous fistula with spinal drainage, a lesion that also causes spinal cord deficits mediated by venous hypertensive myelopathy.

RESULTS

In each case, T2 hypointensity involving the cord periphery was present. This sign has not been previously described in association with either SDAVF or other causes of venous hypertensive myelopathy. It appears, however, to be a relatively constant imaging feature of SDAVF.

CONCLUSION

In the absence of spinal hemorrhage, T2 hypointensity involving the periphery of the spinal cord suggests venous hypertensive myelopathy as a cause of spinal cord dysfunction.

Spinal cord arteriovenous fistulas involving the conus medullaris: presentation, management, and embryologic considerations

BACKGROUND

Spinal cord arteriovenous fistulas (SCAVF) are uncommon congenital lesions that usually involve the most caudal aspects of the cord. We present three cases of SCAVF that illustrate the clinical manifestations and possible management options. The characteristic involvement of the conus medullaris and an associated tethered spinal cord in one of our patient suggests that a disorder of secondary neurulation may be involved in the formation of these arteriovenous shunt lesions.

METHODS

Review of records and radiologic studies in three consecutive patients with SCAVF's treated at this institution.

RESULTS

All three patients had SCAVF involving the lower lumbar spinal cord segments or the conus. One of the conus lesions was associated with tethering of the spinal cord. One small lesion (Type A) was treated surgically, whereas the two larger lesions (Type B) were treated using interventional neuroradiologic techniques.

CONCLUSIONS

Both surgical and endovascular method have a role in management of these unusual spinal cord vascular malformations. The association with tethered cord suggests that the propensity for SCAVM to occur in the most caudal portions of the spinal cord may result from failure of secondary neurulation to properly develop the unique and complex vascular anatomy of the region.

Endovascular thrombolysis for symptomatic cerebral venous thrombosis

OBJECT

The authors sought to treat potentially catastrophic intracranial dural and deep cerebral venous thrombosis by using a multimodality endovascular approach.

METHODS

Six patients aged 14 to 75 years presented with progressive symptoms of thrombotic intracranial venous occlusion. Five presented with neurological deficits, and one patient had a progressive and intractable headache. All six had known risk factors for venous thrombosis: inflammatory bowel disease (two patients), nephrotic syndrome (one), cancer (one), use of oral contraceptive pills (one), and puerperium (one). Four had combined dural and deep venous thrombosis, whereas clot formation was limited to the dural venous sinuses in two patients. All patients underwent diagnostic cerebral arteriograms followed by transvenous catheterization and selective sinus and deep venous microcatheterization. Urokinase was delivered at the proximal aspect of the thrombus in dosages of 200,000 to 1,000,000 IU. In two patients with thrombus refractory to pharmacological thrombolytic treatment, mechanical wire microsnare maceration of the thrombus resulted in sinus patency. Radiological studies obtained 24 hours after thrombolysis reconfirmed sinus/vein patency in all patients. All patients' symptoms and neurological deficits improved, and no procedural complications ensued. Follow-up periods ranged from 12 to 35 months, and all six patients remain free of any symptomatic venous reocclusion. Factors including patients' age, preexisting medical conditions, and duration of symptoms had no statistical bearing on the outcome.

CONCLUSIONS

Patients with both dural and deep cerebral venous thrombosis often have a variable clinical course and an unpredictable neurological outcome. With recent improvements in interventional techniques, endovascular therapy is warranted in symptomatic patients early in the disease course, prior to morbid and potentially fatal neurological deterioration.

Endovascular stent treatment of cervical internal carotid artery aneurysms with parent vessel preservation

BACKGROUND

Aneurysms involving the cervical portion of the internal carotid artery (ICA) frequently result from prior trauma or dissection.

CASE DESCRIPTIONS

Two patients are reported with cervical internal carotid artery aneurysms. In both cases, disease involving the contralateral ICA precluded safe treatment of the aneurysms by ICA occlusion. Endovascular stents placed across the diseased portion of the artery resulted in thrombosis of the aneurysm with preservation of the parent artery.

CONCLUSION

Endovascular stent placement should be considered for treatment of aneurysms involving the cervical ICA when preservation of the parent vessel is necessary.

Dementia resulting from dural arteriovenous fistulas: the pathologic findings of venous hypertensive encephalopathy

PURPOSE

Dural arteriovenous fistulas (DAVFs) are acquired arteriovenous shunts located within the dura. The highly variable natural history and symptomatology of DAVFs range from subjective bruit to intracranial hemorrhage and are related to the lesion's pattern of venous drainage and its effect on the drainage of adjacent brain. We examined the prevalence and features of DAVFs in patients with progressive dementia or encephalopathy.

METHODS

The records and radiologic studies of 40 consecutive patients with DAVFs treated at our institution were reviewed.

RESULTS

Five (12.5%) of 40 consecutive patients with DAVFs had encephalopathy or dementia. In each patient, high flow through the arteriovenous shunt combined with venous outflow obstruction caused impairment of cerebral venous drainage. Hemodynamically, the result was widespread venous hypertension causing diffuse ischemia and progressive dysfunction of brain parenchyma. Results of CT or MR imaging revealed abnormalities in each patient, reflecting the impaired parenchymal venous drainage. Pathologic findings in one patient confirmed the mechanism of cerebral dysfunction as venous hypertension. The hemodynamic mechanism and resulting abnormality appeared identical to that seen in progressive chronic myelopathy resulting from a spinal DAVF (Foix-Alajouanine syndrome). Remission of cognitive symptoms occurred in each patient after embolization.

CONCLUSION

Venous hypertensive encephalopathy resulting from a DAVF should be considered a potentially reversible cause of vascular dementia in patients with progressive cognitive deficits.

Isolated unilateral hypoglossal neuropathy caused by dural arteriovenous fistula

We report a case of isolated hypoglossal nerve paralysis caused by a dural arteriovenous fistula. Diagnosis is discussed with emphasis on conventional and MR angiography. The anatomy of the hypoglossal nerve is reviewed along with more common causes of pathologic conditions.

Hypertension, small size, and deep venous drainage are associated with risk of hemorrhagic presentation of cerebral arteriovenous malformations

OBJECTIVE

To identify clinical and angiographic factors of cerebral arteriovenous malformations (AVMs) associated with hemorrhage to improve the estimation of the risks and help guide management in clinical decision making.

METHODS

We conducted a retrospective analysis of 100 consecutive adults who have presented during the past 3 years to our institution with cerebral AVMs. Angiographic and clinical parameters were evaluated using multivariate logistic regression analysis to analyze factors associated with hemorrhagic presentation.

RESULTS

The group had a mean age of 37.8 years; 53% were men, 48% presented with intracranial hemorrhage, and 40% presented with seizures. All 10 patients with cerebellar AVMs presented with hemorrhage. The following factors were independently associated with AVM hemorrhage: history of hypertension (P = 0.019; odds ratio [OR] = 5.36), nidal diameter <3 cm (P = 0.023: OR = 4.60), and deep venous drainage (P = 0.009: OR = 5.77). Dural arterial supply (P = 0.008; OR = 0.15) was independently associated with decreased risk of bleed. Location, nidal aneurysms, patient age, and smoking were not associated with increased or decreased bleeding risk.

CONCLUSION

In this study, we found small AVM size and deep venous drainage to be positively associated with AVM hemorrhage. Dural supply was associated with a decreased likelihood of hemorrhagic presentation. Hypertension was found to be the only clinical factor positively associated with hemorrhage, a finding not previously reported. Smoking, although associated with increased risk of aneurysmal subarachnoid hemorrhage, was not associated with a higher risk of AVM hemorrhage.

Spontaneous thrombosis of a basilar artery traumatic aneurysm in a child

Traumatic aneurysms are rare and occur most commonly in young adults; however, the relative frequency in the pediatric population is high, owing to the low prevalence of congenital saccular aneurysms in children. Traumatic aneurysms typically involve the anterior circulation, and spontaneous thrombosis is uncommon; hence, surgery is usually necessary. We present a case of a posttraumatic aneurysm in a child that occurred after a fall from a large height and that spontaneously thrombosed.

Dural arteriovenous fistulas involving the superior sagittal sinus: acute presentation with intracranial hemorrhage

BACKGROUND

Intracranial dural arteriovenous fistulas (DAVF) usually drain directly into large dural venous sinuses. Intracranial hemorrhage is therefore unusual with these lesions. Certain subgroups of DAVF may drain into cortical veins causing engorgement, venous hypertension, and hemorrhage. The region of the superior sagittal sinus (SSS), while an unusual location for DAVF, is one in which drainage typically occurs directly into cortical veins.

METHODS

We report on three patients with dural arteriovenous malformations of the superior sagittal sinus, all of whom presented with intracranial hemorrhage. Intraparenchymal hemorrhage in two of the cases was surrounded by excessive edema, suggesting the presence of underlying venous hypertension.

RESULTS

Interventional treatment of all three of the lesions was accomplished at the time of diagnostic angiography.

CONCLUSIONS

SSS DAVF is an uncommon lesion whose presentation is usually with intracranial hemorrhage. Large amounts of edema surrounding an acute hemorrhage may suggest the diagnosis, which usually requires confirmation with angiography. Treatment of SSS DAVF can often be accomplished at the time of diagnostic angiography by embolization using interventional neuroradiologic techniques. When endovascular obliteration of the fistula is not feasible or is incomplete, surgical resection of the DAVF site may be achieved without difficulty.

Angiographic evaluation of aneurysms affecting the central nervous system

This article discusses the indications for, techniques of, and risks associated with cerebral angiography. Various types of aneurysms are described, and there is a discussion of the angiographic features of aneurysms in specific locations. Subarachnoid hemorrhage, post-subarachnoid hemorrhage vasospasm, and the role of post-operative angiography are also covered.

Intracranial aneurysms: detection and characterization with MR angiography with use of an advanced postprocessing technique in a blinded-reader study

PURPOSE

To assess magnetic resonance (MR) angiography for the detection and characterization of angiographically proved intracranial aneurysms by using an advanced method of postprocessing, in a blinded-reader study.

MATERIALS AND METHODS

One hundred fifty-eight vessels were examined with catheter angiography and three-dimensional time-of-flight MR angiography in 44 patients with 63 aneurysms and 15 patients with no aneurysm at catheter angiography. Postprocessing was performed off-line with an advanced multifeature-extraction, ray-tracing algorithm. MR angiograms were interpreted independently by three neuroradiologists blinded to the catheter angiographic results for presence, location, size, and morphology of the aneurysm. Proof of diagnosis was consensus reading of catheter angiograms.

RESULTS

Mean sensitivity for detection of aneurysms was 75% (range, 70%-79%). As a screening tool (ie, detection of at least one aneurysm necessitating catheter angiography), mean sensitivity was 91% for all aneurysms and 95% for aneurysms larger than 3 mm. This method was not adequate for detection of lobulation or size of aneurysm.

CONCLUSION

MR angiography with an advanced method of postprocessing can result in highly sensitive, specific studies for the diagnosis of intracranial aneurysms that are of sufficient size to be considered for surgical treatment, but it is inadequate for characterization of aneurysms.

Angiography of non-atherosclerotic occlusive cerebrovascular disease

The growth of noninvasive imaging has limited the indications for angiographic evaluation in many types of disease involving the CNS. Nevertheless, angiography remains an essential tool for neuroradiologic diagnosis of occlusive cerebrovascular disease. Angiography most faithfully depicts cerebrovascular anatomy and frequently permits diagnosis of disorders that are incompletely evaluated by imaging modalities. In addition, the expanding role of interventional neuroradiologic therapy promises to make the role of angiography one of increasing prominence and importance in the future.

Peer reviewed: the lead fingerprints of gasoline contamination

Isotopic analysis of the lead additives in gasoline can improve estimates of the ages of leaks and spills.

Subarachnoid hemorrhage and aneurysms

Ruptured intracranial aneurysms are the usual cause of acute subarachnoid hemorrhage (SAH). Noncontrast CT is the primary imaging procedure of choice for establishing the diagnosis of SAH. Conventional contrast angiography is the gold standard for establishing the presence of intracranial aneurysms, but CT and MRI have supplementary roles. The pathogenesis, presentation, and imaging of SAH and intracranial aneurysms are discussed.

Interventional neuroradiology of the head and neck

Interventional neuroradiologic techniques continue to assume increasing importance in the management of disorders of the head and neck. Their usefulness includes not only treatment for neoplastic and vascular conditions with embolization but also test occlusion for diagnostic information. Future developments also may extend the usefulness of interventional techniques to additional conditions, including prevention and treatment for ischemic stroke.

Imaging in the trilateral retinoblastoma syndrome

The medical records, CT, and MRI of ten children with trilateral retinoblastoma were reviewed. The intracranial pathology consisted of eight pineal neoplasms and two parasellar lesions, at least seven of the which were calcified. Two lesions demonstrated calcification only (no soft tissue mass) at initial presentation. Hydrocephalus was seen in eight cases, and concurrent or subsequent subarachnoid dissemination was documented in seven. Only one patient is known to be alive at the present time. The imaging features of the midline intracranial tumors mirror those of the ocular neoplasm. As calcification may be the only clue to the presence of the intracranial malignancy, close surveillance of high-risk patients with retinoblastoma with initial CT and follow-up MRI is suggested.

Spinal dural arteriovenous fistula: the pathology of venous hypertensive myelopathy

Spinal dural arteriovenous fistulas (SDAVFs) are the most common type of spinal vascular malformation. The arteriovenous shunts, located entirely outside the spinal cord, cause a clinical picture of chronic progressive myelopathy believed to arise from the effects of increased venous pressure and impaired venous drainage on the spinal cord. Despite their well-described clinical and angiographic features, no reports have documented the spinal cord pathology in a case of angiographically or pathologically proven SDAVF. We report such a patient in whom a spinal cord biopsy supported increased venous pressure as a mechanism of neurologic dysfunction.

Carotid artery invasion by head and neck masses: prediction with MR imaging

PURPOSE

To determine the value of magnetic resonance (MR) imaging in predicting resectability of head and neck neoplasms around the carotid arteries.

MATERIALS AND METHODS

Forty-nine patients (28 male patients and 21 female patients aged 17-79 years; mean, 57.3 years) with head and neck masses and clinical evidence of carotid wall invasion underwent MR imaging. T1-weighted, T2-weighted, and gadolinium-enhanced T1-weighted images were analyzed to determine circumferential involvement of 53 arteries by tumor.

RESULTS

More than 270 degrees of circumferential involvement was considered suggestive of unresectability of the malignant neoplasm; 270 degrees or less was considered lack of invasion. The sensitivity of MR imaging for determination of unresectable disease was 100% (12 of 12 cases), specificity was 88% (36 of 41), and accuracy was 91% (48 of 53). Accuracy was 100% for squamous cell carcinoma (n = 29).

CONCLUSION

Tumor that encompasses more than 270 degrees of the carotid artery probably cannot be removed from the artery. Tumor that involves 270 degrees or less of the artery can be removed.

Deep central arteriovenous malformations of the brain: the role of endovascular treatment

Cerebral deep central arteriovenous malformations (AVMs) are uncommon lesions associated with considerable difficulty in treatment. The authors report a series of 14 deep central AVMs treated by endovascular methods and examine the present role of endovascular treatment. This treatment used alone resulted in complete obliteration of AVMs in approximately 15% of case and reduction in 50% to a size permitting treatment by means of radiosurgery. Reversal of previous neurological signs and symptoms occurred in 35.7% of embolized patients. Overall, nearly 80% of patients had either complete obliteration of the lesion, reduction to a size allowing radiosurgical treatment, or reversal of previous neurological deficits. There were treatment complications in 14.3% of the cases. Endovascular treatment methods may make a significant contribution to the therapy of AVMs that have a particularly poor course and are difficult to treat by other means.

Carcinoid tumor of the sacrum: case report

We present a case of isolated carcinoid tumor of the sacrum and highlight the unusual nature of this lesion. The histopathology suggests hindgut cause, and we discuss the possibility of an underlying congenital tailgut cyst. We review the pathology of these rare anomalies with reference to embryological development and known instances of carcinoid focus. We also present previous reports of sacral carcinoid.

Neuroradiology of central nervous system vasculitis

Evaluation of the patient with suspected vasculitis affecting the nervous system requires consideration of a broad range of differential diagnostic possibilities. Appreciating pertinent neuroradiologic findings as well as understanding the capabilities and limitations of the imaging methods employed is a prerequisite for proper evaluation. Most importantly, integration of the imaging features with clinical and laboratory findings is necessary to maximize the chance of a correct diagnosis.

MR of cervical lymph nodes: comparison of fast spin-echo and conventional spin-echo T2W scans

PURPOSE

In order to explore the utility of fast spin-echo techniques in the neck, 50 consecutive conventional spin-echo (CSE) long TR examinations were compared with 50 consecutive fast spin-echo (FSE) long TR scans for cervical lymph nodes.

MATERIALS AND METHODS

Standard CSE examinations used parameters of 2200/80/1 (TR/TE/excitations), 256 x 128 matrix, 5 mm thick with interslice gaps between 1 and 2.5 mm. FSE studies were employed with TR of 4000/80/2, 256 x 192 matrix, fat suppression and 5 mm contiguous slices. Standard T1-weighted examinations and clinical correlation were used as proof of nodal presence.

RESULTS

Overall vascular flow artefacts, patient motion artefacts, and image quality were comparable between the two techniques. Lymph node detectability was superior with FSE scans (P < 0.05). Typical time saved was approximately 4.5 min with FSE, despite the use of larger matrices, contiguous slices and twice the excitations.

CONCLUSION

FSE is a competitive technique to CSE images in the neck, yielding similar quality images with higher resolution, reduced scan time, and improved lymph node detectability.

Prevalence of MR evidence of diffuse axonal injury in patients with mild head injury and normal head CT findings

PURPOSE

To assess the prevalence of MR evidence for diffuse axonal injury at 1.5 T in patients with normal head CT findings after mild head injury.

METHODS

Twenty consecutive patients with mild head injury (Glasgow Coma Scale, 13 to 15; no subsequent deterioration, loss of consciousness < 20 minutes) and normal head CT findings were examined with MR at 1.5 T. Pulse sequences included a conventional T2-weighted spin-echo sequence (2500-3000/30,80/1[repetition time/echo time/excitations]) and a T2*-weighted gradient-echo sequence (750/40/2, 10 degrees flip angle). Each sequence was read independently by two blinded readers.

RESULTS

The readers agreed that abnormalities compatible with diffuse axonal injury were present in the white matter of 6 (30%) of 20 patients (95% confidence interval, 12% to 54%). Both readers agreed that foci of high signal intensity were present on the T2-weighted spin-echo sequence in 3 (15%) of the 20 cases (95% confidence interval, 3% to 38%) and that foci of hypointensity compatible with hemorrhagic shear injury were present on the T2*-weighted sequence in 4 (20%) of the 20 patients (95% confidence interval, 6% to 44%). Both types of abnormality were noted by the readers in one patient.

CONCLUSIONS

MR shows evidence of diffuse axonal injury in some patients with normal head CT findings after mild head injury. These lesions may represent the pathologic substrate underlying the postconcussion syndrome that occurs in many patients with moderate to severe head injury.

Transient monocular blindness in carotid occlusion testing

A patient developed monocular blindness 23 minutes into a temporary balloon occlusion test of the carotid artery, on the side being tested. His vision returned to normal 1 minute after the balloon was deflated. The authors emphasize the importance of complete frequent neurologic examination during this kind of test.

Role of transcranial Doppler in neuroradiological treatment of intracranial vasospasm

BACKGROUND AND PURPOSE

The expanded role of interventional neuroradiological treatment for post-subarachnoid hemorrhage vasospasm has highlighted the diagnostic utility of transcranial Doppler studies in this condition. The role of transcranial Doppler in follow-up and determining the need for repeat intervention has not been previously emphasized.

SUMMARY OF REPORT

Intracranial angioplasty for clinically evident vasospasm after subarachnoid hemorrhage was performed in four patients. In two patients, transcranial Doppler flow velocities remained elevated despite initial anatomic correction of the vasospasm. Reangiography revealed new areas of involvement by vasospasm. Reangioplasty or papaverine infusion treatment of the new lesions resulted in decreased flow velocities and clinical improvement in all patients.

CONCLUSIONS

Transcranial Doppler has a more significant role than has been previously emphasized in the management of patients undergoing interventional neuroradiological treatment for intracranial vasospasm. Specifically, the persistence of elevated transcranial Doppler flow velocities after intracranial angioplasty suggests the need for repeat angiographic evaluation and possibly further therapy.

Reversible arteriovenous malformation-induced venous hypertension as a cause of neurological deficits

A case of a dural arteriovenous malformation with prominent localizing neurological deficits is reported. The venous drainage of the lesion and the lack of a significant pial supply implicate venous hypertension as the mechanism of neurological dysfunction. This mechanism is supported further by the angiographic changes and the prompt resolution of the deficits after endovascular treatment. This case illustrates the potential for this frequently postulated but rarely confirmed pathophysiological mechanism to cause reversible neurological dysfunction.