Angiography reveals that fluid-attenuated inversion recovery vascular hyperintensities are due to slow flow, not thrombus

BACKGROUND AND PURPOSE

Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH) are commonly encountered on MR imaging studies performed shortly after the onset of acute ischemic stroke. Prior reports have speculated regarding the pathogenesis of this finding, yet definitive correlative angiographic studies have not been performed. We studied the pathophysiologic and hemodynamic correlates of FVH on conventional angiography and concurrent MR imaging sequences.

MATERIALS AND METHODS

Retrospective review of FLAIR and gradient-refocused echo MR imaging sequences acquired immediately before conventional angiography for acute stroke was conducted in a blinded fashion. The presence, location, and morphology of FVH were noted and correlated with markers of thrombotic occlusion and collateral flow on angiography. Angiographic collaterals were graded on a 5-point scale incorporating extent and hemodynamic aspects.

RESULTS

A prospective ischemic stroke registry of 632 patients was searched to identify 74 patients (mean age, 63.4 +/- 20 years; 48% women) having undergone FLAIR sequences immediately before angiography. Median time from FLAIR to angiography was 2.9 hours (interquartile range, 1.1-4.7 hours). FVH were present in 53/74 (72%) of all acute stroke cases with subsequent angiography. FVH distal to an arterial occlusion were associated with a high grade of leptomeningeal collateral blood flow.

CONCLUSIONS

FVH are observed in areas of blood flow proximal and distal to stenosis or occlusion and are noted with more extensive collateral circulation.

Endovascular treatment of middle cerebral artery aneurysms. Overall perioperative results. Apropos of 113 cases

SUMMARY

The endovascular approach is described in 113 middle cerebral artery (MCA) aneurysms. The treatment failed in six cases with no adverse clinical consequences. Out of the 107 treated cases, it was possible to obtain a complete occlusion in 50 aneurysms (47%), whereas a residual aneurysm neck was observed in 54 cases (50%). Follow-up angiograms were performed in 60 cases, showing a 22% rate of further thrombosis of the aneurysm. Recanalization of the aneurysm was observed in 8% of cases, which required retreatment. The technique-related permanent morbidity rate was 9% while the mortality rate was 2%. A review of the surgical and endovascular literature is presented. The endovascular approach is particularly indicated when normal MCA branches do not arise from the aneurysm base. It must be meticulously planned in all other cases. Endovascular coil treatment of MCA aneurysms is feasible, with acceptable morbi-mortality rates.

Impact of collateral flow on tissue fate in acute ischaemic stroke

BACKGROUND

Collaterals may sustain penumbra prior to recanalisation yet the influence of baseline collateral flow on infarct growth following endovascular therapy remains unknown.

METHODS

Consecutive patients underwent serial diffusion and perfusion MRI before and after endovascular therapy for acute cerebral ischaemia. We assessed the relationship between MRI diffusion and perfusion lesion indices, angiographic collateral grade and infarct growth. Tmax perfusion lesion maps were generated and diffusion-perfusion mismatch regions were divided into Tmax >or=4 s (severe delay) and Tmax >or=2 but <4 s (mild delay).

RESULTS

Among 44 patients, collateral grade was poor in 7 (15.9%), intermediate in 20 (45.5%) and good in 17 (38.6%) patients. Although diffusion-perfusion mismatch volume was not different depending on the collateral grade, patients with good collaterals had larger areas of milder perfusion delay than those with poor collaterals (p = 0.005). Among 32 patients who underwent day 3-5 post-treatment MRIs, the degree of pretreatment collateral circulation (r = -0.476, p = 0.006) and volume of diffusion-perfusion mismatch (r = 0.371, p = 0.037) were correlated with infarct growth. Greatest infarct growth occurred in patients with both non-recanalisation and poor collaterals. Multiple regression analysis revealed that pretreatment collateral grade was independently associated with infarct growth.

CONCLUSION

Our data suggest that angiographic collateral grade and penumbral volume interactively shape tissue fate in patients undergoing endovascular recanalisation therapy. These angiographic and MRI parameters provide complementary information about residual blood flow that may help guide treatment decision making in acute cerebral ischaemia.

Statin enhancement of collateralization in acute stroke

Collateral circulation influences cerebral infarction occurrence and size. Statins may improve ischemic stroke outcomes. We evaluated the relationship between prestroke statin use and pretreatment angiographic collateral grade among acute ischemic stroke patients presenting with occlusion of a major cerebral artery. After adjusting for covariates, the statin-treated group had significantly higher collateral scores than non-statin users, suggesting an association between statin use and better collateralization during acute stroke.

Intra-arterial thrombolysis for acute stroke in patients 80 and older: a comparison of results in patients younger than 80 years

BACKGROUND AND PURPOSE

Intra-arterial fibrinolytic therapy is a promising treatment for acute ischemic stroke. Few data are available on its use in elderly patients. The purpose of this study was to compare the baseline characteristics, complications, and outcomes between intra-arterially treated ischemic stroke patients aged > or = 80 years and their younger counterparts.

METHODS

Patients aged > or = 80 years (n = 33) were compared retrospectively with contemporaneous patients aged < 80 years (n = 81) from a registry of consecutive patients treated with intra-arterial thrombolysis over a 9-year period.

RESULTS

The very elderly and younger cohorts were very similar in baseline characteristics, including pretreatment stroke severity (National Institutes of Health Stroke Scale [NIHSS] 17 versus 16), differing only in history of stroke/transient ischemic attack (42% versus 22%, P = .01) and weight (66.8 versus 75.8 kg; P = .02). Significant differences in recanalization (TIMI 2-3) rates could not be detected between the very elderly and younger patients (79% versus 68%, P = .10). Rates of major symptomatic hemorrhage (7% versus 8%) and any intracerebral hemorrhage (39% versus 37%) did not differ. Outcomes at 90 days showed lower rates of excellent functional outcome (mRS < or = 1, 26% versus 40%, P = .02) and survival (57% versus 80%, P = .01) among the very elderly.

CONCLUSIONS

Intra-arterial fibrinolysis in the elderly can be accomplished with recanalization rates and hemorrhage rates equal to that in younger patients. Although mortality rates are higher and good functional outcomes are lower than in younger persons, nondisabling outcomes may be achieved in a quarter of patients. These findings suggest that the investigation and use of intra-arterial thrombolytic treatment in very elderly patients should not be avoided but pursued judiciously.

Cholesterol level and symptomatic hemorrhagic transformation after ischemic stroke thrombolysis

BACKGROUND

Prestroke statin use may improve ischemic stroke outcomes, yet there is also evidence that statins and extremely low cholesterol levels may increase the risk of intracranial hemorrhage. We evaluated the independent effect of statin use and admission cholesterol level on risk of symptomatic hemorrhagic transformation (sHT) after recanalization therapy for acute ischemic stroke.

METHODS

We analyzed ischemic stroke patients recorded in a prospectively maintained registry that received recanalization therapies (IV or intra-arterial fibrinolysis or endovascular embolectomy) at a university medical center from September 2002 to May 2006. The independent effect of premorbid statin use on sHT post intervention was evaluated by logistic regression, adjusting for prognostic and treatment variables known to predict increased HT risk after ischemic stroke.

RESULTS

Among 104 patients, mean age was 70 years, and 49% were men. Male sex, hypertension, statin use, low total cholesterol and low-density lipoprotein (LDL) cholesterol, current smoking, elevated glucose levels, and higher admission NIH Stroke Scale (NIHSS) score were all associated with a greater risk of sHT in univariate analysis. After adjusting for covariates, low LDL cholesterol (odds ratio [OR], 0.968 per 1-mg/dL increase; 95% CI, 0.941 to 0.995), current smoking (OR, 14.568; 95% CI, 1.590 to 133.493), and higher NIHSS score (OR, 1.265 per 1-point increase; 95% CI, 1.047 to 1.529) were independently associated with sHT risk.

CONCLUSIONS

Lower admission low-density lipoprotein cholesterol level with or without statin use, current smoking, and greater stroke severity are associated with greater risk for symptomatic hemorrhagic transformation after recanalization therapy for ischemic stroke.

Endovascular mechanical clot retrieval in a broad ischemic stroke cohort

BACKGROUND AND PURPOSE

Our aim was to describe an expanded experience with endovascular mechanical embolectomy in a broad group of patients, including those not meeting entry criteria for the MERCI multicenter trials.

METHODS

We performed an analysis of all patients with ischemic stroke treated with the Merci Clot Retrieval Device at a single academic center outside of the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) trials.

RESULTS

Twenty-four patients were treated with the device. Nine were MERCI trial ineligible: 4 received intravenous (IV) tissue plasminogen activator (tPA), 1 received IV tPA and was younger than 18 years of age, and 4 had time-to-treatment of longer than 8 hours. Mean age was 64 years (range, 14-89 years; 42% women). Median National Institutes of Health Stroke Scale (NIHSS) score was 21 (range, 11-30). Median symptoms-to-procedure-start time was 303 minutes (range, 85-2385 minutes). Recanalization (Thrombolysis in Myocardial Infarction, 2-3) was achieved in 15/24 (63%). In device-only patients, recanalization occurred in 10/16. In patients who failed IV tPA undergoing rescue embolectomy, recanalization was achieved in 4/5. Three patients unresponsive to device therapy received rescue intra-arterial tPA/abciximab; recanalization was achieved in 2/3. Recanalization was achieved in 3/4 patients in whom treatment was started longer than 8 hours after symptom onset. Asymptomatic hemorrhage occurred in 38%; symptomatic hemorrhage, in 8%. Three device fractures occurred; none worsened clinical outcome. In-hospital mortality was 17%; 90-day mortality, 29%. Good 90-day functional outcome (modified Rankin Scale, <or=2) was achieved by 25% (6/24).

CONCLUSIONS

Endovascular mechanical embolectomy is an effective means of achieving revascularization in patients with acute ischemic stroke, including patients with late treatment start and intravenous tPA failure. Device-based therapy achieved recanalization in nearly two thirds of patients and good clinical outcomes in one fourth, with symptomatic hemorrhage in less than one tenth.

Early MRI and outcomes of untreated patients with mild or improving ischemic stroke

OBJECTIVE

To determine the frequency of early neurologic deterioration with infarct expansion (ENDIE) and poor outcomes among ischemic stroke patients not treated with reperfusion therapies because of rapidly improving or mild symptoms (RIMS) and to study the predictive value of hyperacute MRI in these patients.

METHODS

We identified consecutive patients with symptoms of acute stroke undergoing multimodal MRI within 6 hours of onset without evidence of hemorrhage on imaging. Medical records were reviewed for evidence of early neurologic deterioration within 48 hours. All deteriorating patients had repeat MRI to ascertain causes of worsening. Poor outcome was defined as a discharge modified Rankin Scale (mRS) score of > or = 3.

RESULTS

We identified 74 patients with stroke symptoms < or = 6 hours from onset. Forty had RIMS, and 39 did not receive reperfusion therapies because of RIMS. Among these 39, 4 experienced ENDIE, and 8 were discharged with mRS score of > or = 3. Eight of the 39 patients had large-vessel occlusions on MR angiography. Three of 8 patients with large-vessel occlusion as against only one of 31 patients without occlusion had ENDIE (odds ratio [OR] 18, 95% CI 1.6 to 209, p = 0.02). Four of 8 patients with large-vessel occlusion as against 4 of 31 patients without occlusion had a discharge mRS score of > or = 3 (OR 7, 95% CI 1.2 to 38, p = 0.04).

CONCLUSIONS

About 10% of patients eligible for acute reperfusion therapy excluded on the basis of mild or rapidly improving symptoms show early neurologic deterioration with infarct expansion within 48 hours, and about 20% show poor outcome at discharge. Persisting large-vessel occlusion substantially increases the risk of early worsening and poor functional outcome.

Influence of gender on outcomes after intra-arterial thrombolysis for acute ischemic stroke

Recent data suggest that women obtain greater benefit than men from IV fibrinolysis for acute ischemic stroke. It is unknown whether this gender-thrombolysis advantage extends to those treated with intra-arterial (IA) thrombolysis. The authors evaluated the independent effect of gender among ischemic stroke patients treated with IA fibrinolysis and found no differences in short-term clinical and angiographic outcomes between men and women who received IA thrombolysis for acute ischemic stroke.

Transvenous treatment of spontaneous dural carotid-cavernous fistulas using a combination of detachable coils and Onyx

Three patients with spontaneous dural carotid-cavernous fistulas were treated by using a combination of detachable coils and Onyx liquid embolic agent. Cavernous sinus was accessed via the superior ophthalmic vein or inferior petrous sinus approach. In all cases, a complete angiographic closure of the fistulas was achieved with full recovery from neuro-ophthalmologic symptoms. This report suggests that the controlled and excellent penetration of Onyx is superb for blocking the intricate communication of dural carotid-cavernous fistulas.

Therapeutic management of cerebral arteriovenous malformations. Present role of interventional neuroradiology

This chapter summarizes the authors' experience in the endovascular therapy of cerebral arteriovenous malformations (AVMs). This clinical series includes 660 patients treated from 1980 to 2005. The first 148 patients were treated at University Hospital, in London, Ontario Canada, in association with Drs. Allan Fox, Dave Pelz, John Girvin and Charles Drake. The next 512 patients were treated at UCLA Medical Center, Los Angeles, California in association with Drs. Gary Duckwiler, Reza Jahan, Jacques Dion, Pierre Gobin, Neil Martin and John Frazee. Only patients treated with superselective endovascular/intraoperative catheterization and embolization of avm arterial feeders were included. Cerebral arteriovenous malformations treated by non-selective injection of beads in ICA or vertebral arteries were excluded. Modern neuroimaging modalities associated to the anatomical, topographic and functional evaluations of cerebral avms such as brain CT and CTA, MRI, MRA and functional MRI are all utilized at UCLA Medical Center. They have become essential in the therapeutic management of avms closely related to cerebral eloquent areas (figure 1).

Diffusion-perfusion MRI characterization of post-recanalization hyperperfusion in humans

BACKGROUND

Animal and human studies have demonstrated that postischemic hyperperfusion may occur both early and late timepoints following acute cerebral ischemia.

OBJECTIVE

To use diffusion-perfusion MRI to characterize hyperperfusion in humans following intra-arterial thrombolysis.

METHODS

MRI were performed before treatment, several hours following vessel recanalization, and at day 7 in patients successfully recanalized with intra-arterial thrombolytics.

RESULTS

Hyperperfusion was visualized in 5 of 12 patients within several hours after recanalization (mean volume, 18 mL; range, 7 to 40 mL), and in 6 of 11 patients at day 7 (mean volume, 28 mL; range, 4 to 45 mL). Within the core region of hyperperfusion, mean cerebral blood flow was 2.1 times greater than in the contralateral homologous region at the early time point, and 3.1 times greater at day 7. Seventy-nine percent of voxels with hyperperfusion at day 7 demonstrated infarction at day 7, whereas only 36% of voxels (within the initial hypoperfusion region) not showing hyperperfusion at day 7 demonstrated infarction at day 7. Mean pretreatment apparent diffusion coefficient (ADC) and perfusion values were more impaired in voxels that subsequently developed hyperperfusion compared with other at-risk voxels (all p values < 0.0001). There were no significant differences in the degree of clinical improvement in patients with regions of hyperperfusion versus those without, although sample size limited power to detect group differences.

CONCLUSIONS

Postischemic hyperperfusion, visualized with perfusion MRI in humans following recanalization by intra-arterial thrombolytic therapy, occurred in about 40% of patients within hours and in about 50% of patients at day 7. Hyperperfusion developed mainly in regions that went on to infarction. Compared with other abnormal regions, tissues that developed postischemic hyperperfusion had greater bioenergetic compromise in pretreatment apparent diffusion coefficient values and greater impairment in pretreatment blood flow measures.

Embolization of arteriovenous malformations with Onyx: clinicopathological experience in 23 patients

OBJECTIVE

To report our experience in treatment of arteriovenous malformations (AVMs) using a new liquid embolic agent, Onyx (Micro Therapeutics, Inc., Irvine, CA).

METHODS

Between January 1998 and May 1999, 23 patients (8 men and 15 women) were treated. The patients' average age was 40 years, with seizure being the most common presenting symptom (39%). The average Spetzler-Martin grade on presentation was 3. The average AVM volume before embolization was 14.5 cm3.

RESULTS

We observed an average 63% reduction in AVM volume after 129 arterial feeders were embolized. There were four adverse events. Two patients experienced ischemia because of inadvertent occlusion of an arterial feeder. One of these patients made a full recovery, but the other patient had a permanent deficit. Two other patients experienced transient neurological deficits that resolved within 1 week of embolization. Permanent morbidity was thus 4% (1 of 23 patients). There were no deaths. Twelve patients underwent subsequent radiosurgery, and 11 patients had surgery that resulted in complete resection of their AVMs. Histopathological examinations showed mild acute inflammation in specimens resected 1 day after embolization. Chronic inflammatory changes were observed in specimens resected more than 4 days after embolization. In two patients, angionecrosis of the embolized vessels was noted. No evidence of parenchymal hemorrhage was observed in these patients, and vessel wall integrity was maintained as well.

CONCLUSION

Onyx is a new nonadhesive liquid embolic agent that has been used to treat 23 patients at our institution with good results. Its nonadhesive nature and ease of use make it a promising agent in the future treatment of AVMs.

Volume-rendered helical computerized tomography angiography in the detection and characterization of intracranial aneurysms

OBJECT

The goal of this study was to evaluate the utility of volume-rendered helical computerized tomography (CT) angiography in patients with intracranial aneurysms. The authors compared the abilities of CT angiography, digital subtraction (DS) angiography, and three-dimensional time-of-flight magnetic resonance (MR) angiography to characterize aneurysms.

METHODS

Helical CT angiography was performed in 45 patients with suspected intracranial aneurysms by using volume-rendered multiplanar reformatted (MPR) images. Digital subtraction angiography was performed using biplane angiography. These studies and those performed using MR angiography were interpreted in a blinded manner. Two neurosurgeons and two interventional neuroradiologists independently graded the utility of CT angiography with respect to aneurysm characterization. Fifty-five aneurysms were detected. Of these, 48 were evaluated for treatment. Computerized tomography angiography was judged to be superior to both DS and MR angiography in the evaluation of the arterial branching pattern at the aneurysm neck (compared with DS angiography, p = 0.001, and with MR angiography, p = 0.007), aneurysm neck geometry (compared with DS angiography, p = 0.001, and with MR angiography, p = 0.001), arterial branch incorporation (compared with DS angiography, p = 0.021, and with MR angiography, p = 0.001), mural thrombus (compared with DS angiography, p < 0.001), and mural calcification (compared with DS angiography, p < 0.001, and with MR angiography, p < 0.001). For surgical cases, CT angiography had a significant impact on treatment path (p = 0.001), operative approach (p = 0.001), and preoperative clip selection (p < 0.001). For endovascular cases, CT angiography had an impact on treatment path (p < 0.02), DS angiography study time (p = 0.01), contrast agent usage (p = 0.01), and coil selection (p = 0.02). Computerized tomography angiography provided unique information about 39 (81%) of 48 aneurysms, especially when compared with DS angiography (p = 0.003). The sensitivity and specificity of CT angiography compared with DS angiography was 1. The sensitivity and specificity of CT and DS angiography studies compared with operative findings were 0.98 and 1, respectively.

CONCLUSIONS

Computerized tomography angiography is equal to DS angiography in the detection and superior to DS angiography and MR angiography in the characterization of brain aneurysms. Information contained in volume-rendered CT angiography images had a significant impact on case management.

Histopathologic characteristics of a chronic arteriovenous malformation in a swine model: preliminary study

BACKGROUND AND PURPOSE

The experimental induction of histologic transformations in microvessels of similar caliber to those of nidus vessels of cerebral arteriovenous malformations (AVMs) has not been attempted previously. Our goal was to examine preliminarily the histopathologic characteristics of nidus vessels and the angiographic features of a chronic AVM model in swine.

METHODS

AVM models were fashioned from bilateral carotid retia mirabilia of seven swine after the surgical formation of large unilateral carotid-jugular fistulas. One AVM model was made for immediate use, whereas in the other six, follow-up angiography was obtained at varying intervals (2 to 180 days) after model creation. Light and electron microscopy, immunohistochemistry (using monoclonal antibodies against smooth muscle actin and PC10 against proliferating cell nuclear antigen), and histometry were performed on the nidus vessels of three swine: one acutely created, one 2 months old, and one 6 months old.

RESULTS

Vascular dilatation and tortuosity of the main arterial feeder and draining vein were evident angiographically as early as 4 days after AVM creation, and were maximal in the 6-month-old model. Compared with the acutely created nidus vessels, those in the two chronic models revealed disrupted and attenuated elastica and intimal hyperplasia that was focal ("cushions") or generalized, leading to luminal occlusion. Variable numbers of cells in the tunica media of chronic nidus vessels contained smooth muscle actin. PC10/proliferating cell nuclear antigen immunoreactivity was observed in the endothelium and subendothelial layers. Histometry showed increases in intimal hyperplasia and medial thickness in the chronic vessels.

CONCLUSION

Nidus vessels in this chronic swine AVM model exhibited striking histologic changes similar to those seen in cerebral AVMs. The induced vessel growth seen angiographically and histologically in components of the chronic AVMs was consistent with the presence of persistently raised intravascular hemodynamic loads. This preliminary feasibility study suggests that the realistic histologic characteristics of this chronic AVM model are an attractive feature, and if confirmed in future, more comprehensive, studies would be of benefit in accurate histopathologic interpretation of the effects of superimposed experimental embolotherapy or radiosurgery. This model may provide a useful experimental tool to study the dynamic cellular and tissue events that dictate the development and natural history of AVMs.

Thrombolytic reversal of acute human cerebral ischemic injury shown by diffusion/perfusion magnetic resonance imaging

Diffusion magnetic resonance imaging provides an early marker of acute cerebral ischemic injury. Thrombolytic reversal of diffusion abnormalities has not previously been demonstrated in humans. Serial diffusion and perfusion imaging studies were acquired in patients experiencing acute hemispheric cerebral ischemia treated with intra-arterial thrombolytic therapy within 6 hours of symptom onset. Seven patients met inclusion criteria of prethrombolysis and postthrombolysis magnetic resonance studies, presence of large artery anterior circulation occlusion at angiography, and achievement of vessel recanalization. Mean diffusion-weighted imaging lesion volume at baseline was 23 cm3 (95% confidence interval [95% CI], 8-38 cm3) and decreased to 10 cm3 (95% CI, 3-17 cm3) 2.5 to 9.5 hours after thrombolysis. Mean apparent diffusion coefficient lesion volume decreased from 9 cm3 (95% CI, 2-16 cm3) at baseline to 1 cm3 (95% CI, 0.4-2 cm3) early after thrombolysis. A secondary increase in diffusion volumes was seen in 3 of 6 patients at day 7. In all 4 patients in whom perfusion imaging was obtained before and after treatment, complete resolution of the perfusion deficit was shown. Diffusion magnetic resonance signatures of early tissue ischemic injury can be reversed in humans by prompt thrombolytic vessel recanalization. The ischemic penumbra includes not only the region of diffusion/perfusion mismatch, but also portions of the region of initial diffusion abnormality.

Intraarterial thrombolysis for treatment of acute stroke: experience in 26 patients with long-term follow-up

BACKGROUND AND PURPOSE

Since the approval of intravenous tissue plasminogen activator for acute ischemic stroke, great interest has been generated in cerebral fibrinolysis. Our purpose was to assess long-term outcome and hemorrhagic risk in patients with anterior circulation ischemic stroke treated with intraarterial urokinase.

METHODS

Twenty-six patients were treated within 6 hours of ictus; of these, 21 were followed up for an average of 23 months. Angiographic reperfusion was classified according to thrombolysis in myocardial infarction (TIMI) grades. The Rankin Scale (RS) and the modified Barthel Index (mod BI) were used as outcome measures (good outcome: RS = 0-2, mod BI = 16-20; poor outcome: RS = 3-5, mod BI < or = 15).

RESULTS

Ten of the 21 patients (average age, 48 years) had a good outcome; three (average age, 71 years) had a poor outcome; eight patients (average age, 78 years) died. Partial/complete (successful) recanalization was observed in 11 of 26 patients and minimal or no (unsuccessful) recanalization in 15. Recanalization favored a better outcome: nine of 21 had successful recanalization, with a good outcome in seven; 12 of 21 had unsuccessful reperfusion, with poor outcome/death in nine. Poor outcome was noted in five patients with internal carotid artery (ICA) bifurcation occlusions, four of whom had unsuccessful recanalization and poor outcome or death. Hemorrhage occurred in 10 of the 26 patients, with clinical deterioration in three. The average dose of urokinase was higher in the hemorrhage group, and mortality was higher in patients who hemorrhaged.

CONCLUSION

Intraarterial thrombolysis is feasible in the setting of acute stroke. Successful reperfusion is associated with a better outcome, and the prevalence of hemorrhage does not exceed that which occurs in the natural history of embolic stroke. Poor outcome or death is associated with nonrecanalization, older age, hemorrhage, and ICA bifurcation occlusions.

Comparison of methods for instantaneous angiographic blood flow measurement

Several different algorithms have been reported for measurement of blood flow rates and velocities from digital x-ray angiograms. We compare four videodensitometric methods: (1) distance-density curve matching (DDCM), (2) distance-density curve matching with curve-fitting (DDCM-F), (3) bolus mass tracking with curve-fitting (BMT-F) and (4) fluid continuity method (FCM). We tested the flow algorithms with simulated angiograms and with images obtained from a programmable flow phantom under clinically realistic flow and contrast injection conditions including imperfect mixing. All methods perform well for simulated angiograms. On phantom angiograms with constant flow, all methods tended to underestimate flow velocities by at least 7% and demonstrate high variability between consecutive measurements. The FCM demonstrated relatively low variability, but a large negative bias. The DDCM method was moderately biased and had the highest variability. The BMT-F method demonstrated the lowest bias (-7.1%) and the lowest variability both within (27%) and between (27%) studies. No method yields reliable measurements near the peak contrast opacification, when little or no gradient of contrast is present. The extrapolating version of the BMT-F method was also the most robust for estimation of interframe displacements longer than the field of view.

Lymphomatosis cerebri presenting as a rapidly progressive dementia: clinical, neuroimaging and pathologic findings

Primary central nervous system lymphoma (PCNSL) usually presents with clinical and neuroimaging findings consistent with single or multiple intracranial mass lesions. On cranial magnetic resonance imaging (MRI), such lesions are nearly always contrast enhancing, reflecting disruption of the blood-brain barrier at the site of tumor nodules. We describe 2 cases from the UCLA Medical Center who developed a rapidly progressive dementia due to extensive gray and white matter cerebral lesions involving much of the brain. In the patient who came to autopsy, widely infiltrating, focally necrotic B-cell plasmacytoid lymphoma was noted throughout the cerebral neuraxis. MRI findings in case 2 were consistent with diffuse lymphomatous brain infiltration without mass lesions, which was biopsy proven. We conclude that PCNSL may occur in a diffusely infiltrating form which may occur without MRI evidence of mass lesions or blood-brain barrier compromise. We refer to this entity as 'lymphomatosis cerebri' and add it to the differential diagnosis of a rapidly progressive dementia.

Transvenous embolization of a dural arteriovenous fistula of the cavernous sinus through the contralateral pterygoid plexus

We report a new transvenous endovascular route for treatment of dural arteriovenous fistulas of the cavernous sinus. The cavernous sinus was approached from the contralateral pterygoid plexus and embolization of a dural fistula was performed successfully with Guglielmi detachable coils.

Bilateral neuropathologic changes in a child with hemimegalencephaly

Evaluation of a 7-month-old girl with developmental delay and intractable seizures revealed hemispheric asymmetry and an enlarged right cerebral hemisphere. Because of a history of seizures refractory to medical therapy, she was admitted for right hemispherectomy, but died of complications of surgery. Postmortem brain examination revealed asymmetric enlargement of the right cerebral hemisphere but no gross abnormalities in the left hemisphere. Microscopic examination demonstrated bilateral neuropathologic changes consistent with severe cortical dysplasia in the right cerebral hemisphere and mild cortical dysplasia in the left. Although white matter abnormalities in the unaffected hemisphere have been reported in hemimegalencephaly, bilateral cortical abnormalities, not reported previously in patients with hemimegalencephaly, may account for the varied clinical outcome with medical therapy or after hemispherectomy.