Risk assessment of hemorrhagic transformation of acute middle cerebral artery stroke using multimodal CT.

PURPOSE: Multimodal CT with CT angiography (CTA) and CT perfusion (CTP) are increasingly used in stroke triage. Our aim was to identify parameters most predictive of hemorrhagic transformation (HT), especially symptomatic intracerebral hemorrhage (SICH). METHODS: This retrospective study included patients evaluated by baseline multimodal CT ≤ 9 hours from ictus with acute nonlacunar middle cerebral artery (MCA) territory infarction. Two readers independently evaluated CTP maps for ischemic severity and CTA source images (CTA-SI) for infarct extent (as measured by ASPECTS). Presence of proximal occlusion (ICA or M1) and degree of collateralization (collateral score) were also assessed on CTA. HT was defined as SICH if associated with deterioration ≥ 4-points on NIHSS. Multivariate logistic regression analysis identified independent predictors of SICH. ROC curves selected optimal thresholds. RESULTS: Of 84 patients reviewed, HT occurred in 22 (26.2%) and SICH in 8 (9.5%). Univariate predictors for SICH were proximal occlusion (OR = 8.65, P= .049), collateral score (OR = .34, P= .017), ASPECTS (OR = .46, P= .001), and CBV (OR = .001, P= .005). Multivariate analysis revealed ASPECTS as the only independent predictor with optimal threshold ≤ 5 and sensitivity and specificity of 75.0% and 85.5%, respectively. CONCLUSION: For acute MCA infarcts ≤ 9 hours, the strongest predictor of SICH on multimodal CT was ASPECTS on CTA-SI.

Thoraco-lumbar artery aneurysms associated with a metameric paraspinal lesion presenting with retroperitoneal hemorrhage: Endovascular management.

BACKGROUND: Retroperitoneal hemorrhage is a life-threatening condition. This is the first reported case of rupture of one of multiple thoraco-lumbar artery aneurysms associated with a metameric paraspinal vascular lesion. CASE DESCRIPTION: A 77-year-old female patient presented to the emergency room with a new onset of left-sided low back pain shooting down the leg associated with weakness, numbness, and inability to walk. On physical examination, there was a notable left paraspinal swelling with a harsh bruit audible in the same area, left flank ecchymosis and a positive straight leg raising test. A computed tomography (CT) scan showed a large retroperitoneal hematoma. Digital subtraction angiography showed a large left paraspinal high-flow arteriovenous lesion, with large arterial aneurysms of the left T11, T12, and L1 segmental arteries. The patient was successfully treated with endovascular aneurysm embolization using coils and Onyx-34. Six months following the procedure, the patient had fully recovered, and a follow-up angiogram showed no residual or recurrent aneurysms. CONCLUSION: Thoraco-lumbar artery aneurysms have never previously been described in association with a metameric paraspinal vascular malformation. We report a case of retroperitoneal hemorrhage due to rupture of one of several high-flow artery aneurysms of a paraspinal arteriovenous malformation (AVM). The diagnosis was made on CTA, MRI, and angiography, and the lesion was successfully treated by transarterial embolization.

Endovascular embolization of cervical hemangiopericytoma with Onyx-18: case report and review of the literature.

Cervical hemangiopericytoma (HPC) is a rare tumor involving dura and bone. Because HPC shares some imaging features with meningioma, hemangioblastoma, schwannoma and solitary fibrous tumors; histology with appropriate immunohistochemistry is essential for its diagnosis and treatment. HPC is highly vascular and has a high rate of local recurrence following resection. Thus it can pose significant therapeutic challenges. To the best of our knowledge this is the 13th reported case of HPC of the cervical spine and the first case of cervical HPC treated using embolization with Onyx-18. In addition, a systematic review of the literature is presented describing previous experience with HPC of the cervical region. The case of a 61-year-old woman is reported who presented with a 7 month history of dizziness, mild ataxia and left-sided tinnitus when supine. MRI of the cervical spine demonstrated a gadolinium enhancing mass arising from the dorsal cervical dura, extending from the occiput to C2, with internal flow voids and extension into the C2 lamina and spinous process. Digital subtraction angiography demonstrated multiple corkscrew-shaped supplying vessels, marked hypervascularity, rapid arteriovenous shunting and delayed contrast washout. Super selective injection of Onyx-18 yielded approximately 90% embolization of the lesion, followed by subtotal resection and radiotherapy. Histology confirmed the presumptive diagnosis of HPC. Preoperative embolization with Onyx-18 should be considered for large HPC as it may decrease the risk of intraoperative hemorrhage. In this case, embolization with Onyx-18 did not preclude histopathologic diagnosis of HPC.

Transluminal balloon angioplasty for symptomatic distal vasospasm refractory to medical therapy in patients with aneurysmal subarachnoid hemorrhage.

BACKGROUND: Cerebral vasospasm (VSP) is a major cause of morbidity and mortality associated with subarachnoid hemorrhage. The current endovascular paradigm for VSP refractory to medical therapy is to perform angioplasty for proximal vessel VSP and vasodilator infusion for distal vessel VSP. OBJECTIVE: To report our experience with a large series of balloon angioplasty for distal VSP refractory to medical therapy in patients with aneurysmal subarachnoid hemorrhage. METHODS: This was a retrospective series of 32 patients with subarachnoid hemorrhage and symptomatic VSP refractory to medical therapy who were treated with balloon angioplasty for distal vessel VSP. Immediate angiographic results, procedure-related complications, and clinical outcomes were assessed. RESULTS: From September 2001 to January 2010, 32 patients with symptomatic VSP refractory to medical therapy underwent angioplasty for distal arterial VSP. There were 26 women (81.3%); patients were 29 to 67 years of age. A total of 175 vessels were angioplastied (95 proximal and 80 distal). The only complication was rupture of an incompletely clipped aneurysm that was treated by immediate coiling and did not result in any clinical worsening. Repeated treatment was needed for 6 arteries (6 of 80, 7.5%). There were no procedure-related symptomatic complications. Good outcomes (modified Rankin Scale score ≤ 2) were observed in 23 of 28 patients (82.1%) with follow-up. CONCLUSION: Balloon angioplasty for distal VSP is safe and effective and decreases the need for repeated intraarterial treatments seen with infusion of vasodilator.

What ASPECTS value best predicts the 100-mL threshold on diffusion weighted imaging? Study of 150 patients with middle cerebral artery stroke.

PURPOSE: Infarct volume ≥100 mL on diffusion weighted imaging (DWI) predicts symptomatic hemorrhagic transformation and poor outcome. Our aim was to determine the correlation between the Alberta Stroke Program Early CT Score (ASPECTS) and infarct volume and to identify the optimal value for describing infarcts ≥100 mL. METHODS: This was a retrospective study of acute infarcts isolated to the middle cerebral artery territory imaged by DWI <48 hours from ictus. Two neuroradiologists blinded to volumetric measurements assigned ASPECTS while a third observer used a semi-automated thresholding technique to determine infarct volume. Correlation of ASPECTS and infarct volume was determined using Spearman's rank coefficient (ρ). Receiver-operating characteristics (ROC) curve analysis was performed to identify the optimal ASPECTS for ≥100 mL. RESULTS: One hundred and fifty patients were evaluated; the median and range for infarct volumes were 32.3 and 10.0-277 mL, respectively. The median and range for ASPECTS were 7 and 1-9, respectively. A strong correlation was found with ρ=-.807 (P < .0001). 22 (14.7%) infarcts were ≥100 mL and the area under the ROC curve was .976 (P < .0001). The optimal ASPECTS was ≤3 with sensitivity and specificity of 77.3% and 97.7%, respectively. CONCLUSION: ASPECTS may serve as a surrogate marker of infarct extent on DWI.

The vertebral artery and the cervical pedicle: morphometric analysis of a critical neighborhood.

OBJECT The purpose of this retrospective study was to quantify the anatomical relationship between the vertebral artery (VA), the cervical pedicle, and its surrounding structures, including the incidence of irregularities. Additionally, data delineating a "safe zone," and these data's application during instrumentation with transpedicular cervical screw fixation were considered. The anatomical proximity of the VA to the cervical pedicle prevents spine surgeons from preferring cervical pedicle screws (CPSs) over lateral mass screws at levels C3-6. Accurate placement of CPSs is often difficult to determine, because this definition can vary between 1 and 4 mm of lateral "noncritical" and "critical" pedicle breaches. No previous study in a western population has investigated the VA's proximity to the cervical pedicle, its percentage of occupancy in the transverse foramen (TF), and the incidence of irregular VA pathways. METHODS One hundred twenty-seven consecutive patients who underwent CT angiography of the neck were enrolled in this study. The measurements included the following: medial pedicle border to VA; lateral pedicle border to VA; pedicle diameter (PD); sagittal diameter of the VA; coronal diameter of the VA; sagittal diameter of the TF; and coronal diameter of the TF. The cross-sections of the VA and the TF were measured to determine the occupation ratio of the VA. In addition, a safe zone was defined based on all lateral pedicle border to VA measurements in which the VA was within the TF. The level of entry of the VA into the TF as well as irregularities of the VA and the cervical pedicles were recorded. RESULTS Vertebral artery dominance on the left side was seen in 69.3% of cases. The mean PD increased from 4.9 to 6.5 mm (from C-3 to C-7, respectively). Statistically significantly bigger PDs were seen in males. The mean PD at C-2 was 5.6 mm. Entry of the VA at C-6 was seen in approximately 80% of cases. The TF occupation ratio of the VA was found to be the greatest in C-4 and C-7 (37.1 and 74.2%, respectively). The safe zone increased from C-2 to C-6 (1.1 to 1.7 mm, respectively), but was only 0.65 mm at C-7. In 23.6% of cases, an irregular pathway of the VA or irregular anatomy of a cervical pedicle was seen, with the highest incidence of irregularities found at C-2. CONCLUSIONS Computed tomography angiography is a valuable tool that can help determine the relationships between cervical pedicles and the VA as well as irregular VA pathways. Pedicle diameter, safe zone, and occupational ratio of the VA in the foramen determine the risk associated with instrumentation and should be assessed individually. Based on the authors' measurements, C-4 and C-7 can be considered critical levels for CPS placement. Because of this and the high incidence of irregular VA pathways and different entry points, it may be helpful to review neck CT angiography studies before considering posterior instrumentation procedures in the cervical spine.

Bilateral carotid and bilateral vertebral artery dissection following facial massage.

A 50-year-old woman underwent facial massage. After 13 days, she experienced left retro-orbital pain, ptosis, and miosis. Magnetic resonance imaging (MRI) showed stenotic dissection of bilateral cervical internal carotid and vertebral arteries. The intracranial vasculature was intact. She was treated conservatively with long-term oral anticoagulation and remains asymptomatic 18 months later.

Internal carotid aplasia/hypoplasia and intracranial saccular aneurysms: series of three new cases and systematic review of the literature.

BACKGROUND AND PURPOSE: Abnormal arterial flow dynamics and intracranial collateral pathways can be seen in patients with congenital internal carotid artery (ICA) aplasia or hypoplasia. Here we seek to evaluate whether ICA aplasia/hypoplasia is associated with an increased prevalence of intracranial saccular aneurysm relative to carotid rete mirabile. METHODS: We combined our experience of three cases with 148 previous publications to form a retrospective series including 132 cases of ICA aplasia, 33 cases of ICA hypoplasia, and 34 cases of carotid rete mirabile. RESULTS: After excluding cases lacking angiograms, ICA aplasia/hypoplasia was more commonly associated with aneurysm (45/158, 27.8%) compared with rete mirabile (2/34, 5.9%). A significantly greater overall aneurysm prevalence was seen among ICA aplasia/hypoplasia patients age 30 years or older (38/101, 36.6%) than in younger individuals (7/48, 14.6%). CONCLUSIONS: Intracranial saccular aneurysm is more strongly associated with ICA aplasia/hypoplasia than rete mirabile. An increased aneurysm prevalence among older individuals with ICA aplasia/hypoplasia suggests an acquired etiology. Magnetic resonance angiography (MRA) is recommended in the initial evaluation of ICA aplasia/hypoplasia to evaluate for intracranial saccular aneurysm, particularly after the third decade of life.

Combined surgical and endovascular management of a complex posttraumatic dural arteriovenous fistula of the tentorium and straight sinus.

Diagnosis and management of a complex tentorial dural arteriovenous fistula (DAVF) of the straight sinus with vein of Galen aneurysmal dilatation is presented. A 65-year-old woman with remote history of cranial gunshot lapsed into coma after months of progressive neurological decline. Computed tomography brain scan showed cerebellar hemorrhage while arteriography demonstrated a complex arteriovenous fistula of an isolated straight sinus and tentorium with extensive arterial supply. First extracranial then intracranial arterial feeders to the fistula were occluded in separate procedures following initial presentation. Eleven days after presentation, an occipital burr-hole craniotomy was performed, the isolated straight sinus was cannulated under fluoroscopic guidance, and the fistula eradicated with multiple thrombogenic fibered platinum and Gugliemi detachable coils. Staged embolization now represents the standard of care for many complex DAVFs. A multi-disciplinary surgical and endovascular approach is a valuable combination to cure deep lesions with limited surgical or transvascular access.

HIV-1-associated dementia: a metabolic encephalopathy perpetrated by virus-infected and immune-competent mononuclear phagocytes.

Infection of the nervous system by HIV-1 commonly causes a broad range of cognitive, behavioral, and motor abnormalities called, in its most severe form, HIV-1-associated dementia (HAD). HAD is a metabolic encephalopathy caused by productive viral infection of brain mononuclear phagocytes (MPs) (perivascular and parenchymal brain macrophages and microglia) and sustained by paracrine-amplified, inflammatory, neurotoxic responses. MP neurotoxins are, in large measure, homeostatic secretory products that can have a negative effect on neuronal cell function when produced in abundance. Proinflammatory cytokines, chemokines, platelet-activating factor, arachidonic acid and its metabolites, nitric oxide, quinolinic acid, progeny virions, and viral structural and regulatory proteins are all included as part of these cellular and viral toxic elements. In addition, neuronal damage can occur directly by engaging specific receptors or through inducing widespread inflammatory activities in brain tissue that ultimately induce neuronal demise. The mechanisms for immune-and viral-mediated neural injury in HAD are made more striking by the effects of abused drugs on cognitive function. Ultimately, linkages between neuronal function and disordered MP immunity will provide insights into how HIV-1 infection of the brain leads to compromised mental function as well as providing clues into the pathogenesis of other neurodegenerative disorders.

Macrophages, chemokines and neuronal injury in HIV-1-associated dementia.

Human immunodeficiency virus type-one (HIV- 1)-associated dementia (HAD) is manifested as a spectrum of behavioral, motor and cognitive dysfunctions. The disorder commonly occurs during late stage HIV disease and remains an important complication despite highly active antiretroviral therapies. A metabolic encephalopathy, fueled by neurotoxic secretions from brain mononuclear phagocytes (MP) (macrophages and microglia) underlies HIV- I neuropathogenesis. One pivotal question, however, is how brain MP evolve from neurotrophic to neurotoxic cells. The interplay between the virus, the macrophage and the neuron has just recently begun to be unraveled. Along with a multitude of other MP secretory products, chemokines effect neuronal function by engaging neuronal receptors then activating pathways that alter synaptic transmission, cell growth, injury and protection. Both neurons and glia secrete chemokines. Interestingly, HIV-1 and its gene products can mimic chemokine neuronal signaling by binding to neuronal chemokine receptors or by other non-specific mechanisms. The elucidation of mechanisms involved in chemokine-mediated neural compromise will likely provide unique insights into the pathogenesis and treatment, not only of HAD, but of a wide range of neurodegenerative disorders.

Impaired spatial cognition and synaptic potentiation in a murine model of human immunodeficiency virus type 1 encephalitis.

Injection of human immunodeficiency virus type 1 (HIV-1)-infected human monocyte-derived macrophages (MDMs) into the basal ganglia of severe combined immunodeficient mice recapitulates histopathologic features of HIV-1 encephalitis (HIVE). Here, we show that the neural damage in HIVE mice extends beyond the basal ganglia and is associated with cognitive impairment. Morris water maze tests showed impaired spatial learning 8 d after MDM injection. Moreover, impaired synaptic potentiation in the hippocampal CA1 subregion was demonstrated at 8 and 15 d. By day 15, post-tetanic, short-term, and long-term potentiation were reduced by 14.1, 29.5, and 45.3% in HIVE mice compared with sham-injected or control animals. Neurofilament (NF) and synaptophysin (SP) antigens were decreased significantly in the CA2 hippocampal subregion of HIVE mice with limited neuronal apoptosis. By day 15, the CA2 region of HIVE mice expressed 3.8- and 2.6-fold less NF and SP than shams. These findings support the notion that HIV-1-infected and immune-competent brain macrophages can cause neuronal damage at distant anatomic sites. Importantly, the findings demonstrate the value of the model in exploring the physiological basis and therapeutic potential for HIV-1-associated dementia.