R T Higashida

University of California, San Francisco, San Francisco, California, United States

Are you R T Higashida?

Claim your profile

Publications (371)1633.54 Total impact

  • Journal of Neurosurgery 08/2015; DOI:10.3171/2015.1.JNS142795 · 3.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECT Retroclival hematomas are rare, appearing mostly as posttraumatic phenomena in children. Spontaneous retroclival hematoma (SRH) in the absence of trauma also has few descriptions in the literature. None of the reported clinical cases features the combination of an SRH and intraventricular hemorrhage (IVH). Nevertheless, despite extensive cases of idiopathic or angiographically negative subarachnoid hemorrhage (SAH) of the posterior fossa, only a single case report of a patient with a unique spontaneous retroclival hematoma has been identified. In this study, the authors reviewed the presentation, management, and clinical outcome of this rare entity. METHODS The authors performed a retrospective analysis of all patients with diagnosed SRH at their institution over a 3-year period. Collected data included clinical history, laboratory results, treatment, and review of all imaging studies performed. RESULTS Four patients had SRH. All were appropriately evaluated for coagulopathic and/or traumatic etiologies of hemorrhage, though no etiology could be found. Moreover, all of the patients demonstrated SRH that both clearly crossed the basioccipital synchondrosis and was contained within a nondependent configuration along the retroclival dura mater. CONCLUSIONS Spontaneous retroclival hematoma, often associated with IVH, is a rare subtype of intracranial hemorrhage frequently recognized only when MRI demonstrates compartmentalization of the posterior fossa hemorrhage. When angiography fails to reveal an underlying lesion, SRH patients, like patients with traditional angiographically negative SAH, enjoy a remarkably good prognosis.
    Journal of Neurosurgery 08/2015; DOI:10.3171/2015.2.JNS142221 · 3.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To develop a strategy of achieving targeted collection of endothelial cells (ECs) by endovascular methods and analyzing the gene expression profiles of collected single ECs.
  • [Show abstract] [Hide abstract]
    ABSTRACT: A minority of intracranial dural arteriovenous fistulas progress with time. We sought to determine features that predict progression and define outcomes of patients with progressive dural arteriovenous fistulas. We performed a retrospective imaging and clinical record review of patients with intracranial dural arteriovenous fistula evaluated at our hospital. Of 579 patients with intracranial dural arteriovenous fistulas, 545 had 1 fistula (mean age, 45 ± 23 years) and 34 (5.9%) had enlarging, de novo, multiple, or recurrent fistulas (mean age, 53 ± 20 years; P = .11). Among these 34 patients, 19 had progressive dural arteriovenous fistulas with de novo fistulas or fistula enlargement with time (mean age, 36 ± 25 years; progressive group) and 15 had multiple or recurrent but nonprogressive fistulas (mean age, 57 ± 13 years; P = .0059, nonprogressive group). Whereas all 6 children had fistula progression, only 13/28 adults (P = .020) progressed. Angioarchitectural correlates to chronically elevated intracranial venous pressures, including venous sinus dilation (41% versus 7%, P = .045) and pseudophlebitic cortical venous pattern (P = .048), were more common in patients with progressive disease than in those without progression. Patients with progressive disease received more treatments than those without progression (median, 5 versus 3; P = .0068), but as a group, they did not demonstrate worse clinical outcomes (median mRS, 1 and 1; P = .39). However, 3 young patients died from intracranial venous hypertension and intracranial hemorrhage related to progression of their fistulas despite extensive endovascular, surgical, and radiosurgical treatments. Few patients with dural arteriovenous fistulas follow an aggressive, progressive clinical course despite treatment. Younger age at initial presentation and angioarchitectural correlates to venous hypertension may help identify these patients prospectively. © 2015 American Society of Neuroradiology.
    American Journal of Neuroradiology 07/2015; DOI:10.3174/ajnr.A4391 · 3.59 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECT Large arteriovenous malformations (AVMs) remain difficult to treat, and ideal treatment parameters for volume-staged stereotactic radiosurgery (VS-SRS) are still unknown. The object of this study was to compare VS-SRS treatment outcomes for AVMs larger than 10 ml during 2 eras; Era 1 was 1992-March 2004, and Era 2 was May 2004-2008. In Era 2 the authors prospectively decreased the AVM treatment volume, increased the radiation dose per stage, and shortened the interval between stages. METHODS All cases of VS-SRS treatment for AVM performed at a single institution were retrospectively reviewed. RESULTS Of 69 patients intended for VS-SRS, 63 completed all stages. The median patient age at the first stage of VS-SRS was 34 years (range 9-68 years). The median modified radiosurgery-based AVM score (mRBAS), total AVM volume, and volume per stage in Era 1 versus Era 2 were 3.6 versus 2.7, 27.3 ml versus 18.9 ml, and 15.0 ml versus 6.8 ml, respectively. The median radiation dose per stage was 15.5 Gy in Era 1 and 17.0 Gy in Era 2, and the median clinical follow-up period in living patients was 8.6 years in Era 1 and 4.8 years in Era 2. All outcomes were measured from the first stage of VS-SRS. Near or complete obliteration was more common in Era 2 (log-rank test, p = 0.0003), with 3- and 5-year probabilities of 5% and 21%, respectively, in Era 1 compared with 24% and 68% in Era 2. Radiosurgical dose, AVM volume per stage, total AVM volume, era, compact nidus, Spetzler-Martin grade, and mRBAS were significantly associated with near or complete obliteration on univariate analysis. Dose was a strong predictor of response (Cox proportional hazards, p < 0.001, HR 6.99), with 3- and 5-year probabilities of near or complete obliteration of 5% and 16%, respectively, at a dose < 17 Gy versus 23% and 74% at a dose ≥ 17 Gy. Dose per stage, compact nidus, and total AVM volume remained significant predictors of near or complete obliteration on multivariate analysis. Seventeen patients (25%) had salvage surgery, SRS, and/or embolization. Allowing for salvage therapy, the probability of cure was more common in Era 2 (log-rank test, p = 0.0007) with 5-year probabilities of 0% in Era 1 versus 41% in Era 2. The strong trend toward improved cure in Era 2 persisted on multivariate analysis even when considering mRBAS (Cox proportional hazards, p = 0.055, HR 4.01, 95% CI 0.97-16.59). The complication rate was 29% in Era 1 compared with 13% in Era 2 (Cox proportional hazards, not significant). CONCLUSIONS VS-SRS is an option to obliterate or downsize large AVMs. Decreasing the AVM treatment volume per stage to ≤ 8 ml with this technique allowed a higher dose per fraction and decreased time to response, as well as improved rates of near obliteration and cure without increasing complications. Reducing the volume of these very large lesions can facilitate a surgical approach for cure.
    Journal of Neurosurgery 07/2015; DOI:10.3171/2014.12.JNS141308 · 3.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The proper role of endovascular treatment of cervicocerebral atherosclerosis is unclear. Posterior circulation disease has not been investigated as extensively as disease in the anterior circulation. In this study, we characterized the rates of technical success, transient ischemic attack, stroke, and death or disability, for both acute and elective endovascular treatment of atherosclerosis in the vertebrobasilar system. We identified patients with atherosclerosis of the vertebrobasilar circulation who underwent endovascular intervention at our hospital through retrospective medical record review, and evaluated the association between lesion and treatment features and subsequent stroke, death, or disability at 30 days and 1 year. We identified 136 lesions in 122 patients, including 13 interventions for acute strokes. Technical success was achieved in 123 of 136 cases (90.4%). Elective procedures had higher rates of technical success (6.5% vs 15.4%, p=0.21) and better clinical outcomes. In multivariate analysis, intracranial lesions were associated with more disability (modified Rankin Scale score >2) at 30 days (OR 7.1, p=0.01) and 1 year (OR 10, p=0.03). Patients with non-hypoperfusion related symptoms had fewer strokes at follow-up at 1 year when treated after an asymptomatic interval of >10 days compared with those treated within 10 days of the presenting symptoms (OR 0.2, p=0.03). Statin treatment prior to intervention was associated with favorable outcomes across several examined endpoints. Preoperative antiplatelet treatment was associated with lower rates of disability at 30 days and 1 year (OR 0.1, p<0.01 and OR 0.07, p=0.01, respectively), and preoperative anticoagulation treatment was associated with higher rates of death at 30 days, particularly when prescribed for reasons other than atrial fibrillation (OR 6.4, p=0.01). Endovascular treatment of symptomatic vertebrobasilar atherosclerosis can be performed safely and with good outcomes. Technical results were better for those with extracranial disease while clinical outcomes were more favorable in those patients with non-progressive symptoms in the subacute period and those receiving statin therapy. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    Journal of Neurointerventional Surgery 03/2015; DOI:10.1136/neurintsurg-2014-011633 · 2.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The lack of safe and reliable methods to sample vascular tissue in situ limits discovery of the underlying genetic and pathophysiological mechanisms of many vascular disorders, including aneurysms. We investigated the feasibility and comparable efficacy of in vivo vascular endothelial cell sampling using a spectrum of endovascular devices. Using the rabbit elastase carotid aneurysm model we evaluated the performance of existing aneurysmal coils, intracranial stents, and stent-like devices to collect vascular endothelial cells. Additionally, we modified a subset of devices to assess the effects of alterations to coil pitch, coil wire contour, and stent surface finishing. Device performance was evaluated by (1) the number of viable endothelial cells harvested, (2) the degree of vascular wall damage analyzed using digital subtraction angiography and histopathological analysis, and (3) the ease of device navigability and retrieval. Isolated cells underwent immunohistochemical analysis to confirm cell type and viability. Coil and stent specifications, technique, and endothelial cell counts were tabulated and statistical analysis performed. Using conventional detachable-type and modified aneurysm coils 11 of 14 (78.6%) harvested endothelial cells with a mean of 7.93 (±8.33) cells/coil, while 15 of 15 (100%) conventional stents, stent-like devices and modified stents harvested endothelial cells with a mean of 831.33 (±887.73) cells/device. Coil stiffness was significantly associated with endothelial cell count in univariate analysis (p = 0.044). For stents and stent-like devices univariate analysis demonstrated stent-to-aorta diameter ratios (p = 0.001), stent length (p = 0.049), and the use of a pulling retrieval technique (p = 0.019) significantly predictive of endothelial cell counts, though a multivariate model using these variables demonstrated only the stent-to-aorta diameter ratio (p = 0.029) predictive of endothelial cell counts. Modified devices did not significantly impact harvesting. The efficacy and safety of existing aneurysm coils, intracranial stents and stent-like devices in collecting viable endothelial cells was confirmed. The technique is reproducible and the quantity and quality of collected endothelial cells is adequate for targeted genetic analysis. © The Author(s) 2015 Reprints and permissions:]br]sagepub.co.uk/journalsPermissions.nav.
    Interventional Neuroradiology 02/2015; 21(1). DOI:10.15274/INR-2015-10103 · 0.78 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Intracranial hemorrhage is the most serious outcome for brain arteriovenous malformations. This study examines associations between venous characteristics of these lesions and intracranial hemorrhage. Statistical analysis was performed on a prospectively maintained data base of brain AVMs evaluated at an academic medical center. DSA, CT, and MR imaging studies were evaluated to classify lesion side, drainage pattern, venous stenosis, number of draining veins, venous ectasia, and venous reflux. Logistic regression analyses were performed to identify the association of these angiographic features with intracranial hemorrhage of any age at initial presentation. Exclusively deep drainage (OR, 3.42; 95% CI, 1.87-6.26; P < .001) and a single draining vein (OR, 1.98; 95% CI, 1.26-3.08; P = .002) were associated with hemorrhage, whereas venous ectasia (OR, 0.52; 95% CI, 0.34-0.78; P = .002) was inversely associated with hemorrhage. Analysis of venous characteristics of brain AVMs may help determine their prognosis and thereby identify lesions most appropriate for treatment. © 2015 American Society of Neuroradiology.
    American Journal of Neuroradiology 01/2015; 36(5). DOI:10.3174/ajnr.A4224 · 3.59 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Object: Although the development and prevalence of cerebral vasospasm (CV) has been extensively investigated in adults, little data exist on the development of CV in children. The authors hypothesized that even though children have highly vasoreactive arteries, because of a robust cerebral collateral blood flow, they rarely develop symptomatic CV. Methods: The authors retrospectively reviewed their university hospital's neurointerventional database for children (that is, patients ≤ 18 years) who were examined or treated for aneurysmal or traumatic subarachnoid hemorrhage (SAH) during the period 1990-2013. Images from digital subtraction angiography (DSA) were analyzed for the extent of CV and collateralization of the cerebral circulation. Results from transcranial Doppler (TCD) ultrasonography were correlated with those from DSA. Cerebral vasospasm on TCD ultrasonography was defined according to criteria developed for adults. Clinical outcomes of CV were assessed with the pediatric modified Rankin Scale (mRS). Results: Among 37 children (21 boys and 16 girls ranging in age from 8 months to 18 years) showing symptoms of an aneurysmal SAH (comprising 32 aneurysms and 5 traumatic pseudoaneurysms), 17 (46%) had CV confirmed by DSA; CV was mild in 21% of these children, moderate in 50%, and severe in 29%. Only 3 children exhibited symptomatic CV, all of whom had poor collateralization of cerebral vessels. Among the 14 asymptomatic children, 10 (71%) showed some degree of vessel collateralization. Among 16 children for whom TCD data were available that could be correlated with the DSA findings, 13 (81%) had CV according to TCD criteria. The sensitivity and specificity of TCD ultrasonography for diagnosing CV were 95% and 59%, respectively. The time to CV onset detected by TCD ultrasonography was 5 ± 3 days (range 2-10 days). Twenty-five (68%) of the children had good long-term outcomes (that is, had mRS scores of 0-2). Conclusions: Children have a relatively high incidence of angiographically detectable, moderate-to-severe CV. Children rarely develop symptomatic CV and have good long-term outcomes, perhaps due to robust cerebral collateral blood flow. Criteria developed for detecting CV with TCD ultrasonography in adults overestimate the prevalence of CV in children. Larger studies are needed to define TCD ultrasonography-based CV criteria for children.
    Journal of Neurosurgery Pediatrics 01/2015; 15(3):1-9. DOI:10.3171/2014.9.PEDS14313 · 1.48 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background and Purpose Endovascular sampling and characterization from patients can provide very useful information about the pathogenesis of different vascular diseases, but it has been much limited by the lack of an effective method of endothelial cell (EC)enrichment. We optimized the EC yield and enrichment from conventional guide wires by laser capture microdissection (LCM) and fluorescence activated cell sorting (FACS) techniques, and addressed the feasibility of using these enriched ECs for downstream gene expression detection. Methods Iliac artery endovascular samples from 10 patients undergoing routine catheter angiography were collected using conventional 0.038 inch J-shape guide wires. Each of the samples were equally divided into two parts, which were respectively used for EC enrichment by immunocytochemistry -coupled LCM or multiple color FACS. After RNA extraction and reverse transcription, the amplified cDNA were used for quantitative polymerase chain reaction (qPCR). Results Fixed ECs, with positive CD31 or vWF fluorescent signal and endothelial like nucleus, were successfully separated by LCM and live single ECs were sorted on FACS by a seven color staining panel. EC yields by LCM and FACS were 51 ± 22 and 149 ± 56 respectively (P < 0.001). The minimum number of fixed ECs from ICC-coupled LCM for acceptable qPCR results of endothelial marker genes was 30, while acceptable qPCR results as enriched by FACS were attainable from a single live EC. Conclusion Both LCM and FACS can be used to enrich ECs from conventional guide wires and the enriched ECs can be used for downstream gene expression detection. FACS generated a higher EC yield and the sorted live ECs may be used for single cell gene expression detection.
    Journal of Biotechnology 10/2014; 192. DOI:10.1016/j.jbiotec.2014.07.434 · 2.87 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background Intracranial atherosclerotic disease (ICAD) causes substantial morbidity and mortality. Treatment decisions have most commonly been driven by the degree of luminal stenosis. This study compares ICAD lesion stability features with percentage stenosis for associations with adverse outcomes following treatment with stents. Materials and methods Retrospective analysis was performed of prospectively maintained procedure logs. Lesions were classified by symptom type as hypoperfusion, non-hypoperfusion, or indeterminate, and pretreatment asymptomatic intervals were noted. Hypoperfusion lesions and indeterminate or non-hypoperfusion lesions with ≥14 days of asymptomatic interval were classified as stable. Percentage stenosis was calculated and compared against these other symptom features for value in predicting technical complication, ischemic stroke, disability, or death at 90 days and 2 years using univariate and multivariate analysis. Results 130 lesions were treated in 124 patients. The only statistically significant percent stenosis finding was lesions with 60–99% stenosis were less likely to have technical complications. In univariate analysis, stroke at 2 years was less common with hypoperfusion and stable lesions. In multivariate analysis, only hypoperfusion status was associated with lower stroke rates at 2 years. Conclusions Lesion stability features, particularly non-hypoperfusion symptomatology, outperform percentage stenosis in predicting outcomes following treatment of ICAD with stents. Further examination is needed to better classify the natural history of ICAD and more precisely classify lesion stability.
    Journal of Neurointerventional Surgery 07/2014; 6 Suppl 1:A7. DOI:10.1136/neurintsurg-2014-011343.12 · 2.77 Impact Factor
  • S Hetts · T Tsai · D Cooke · M Amans · J Narvid · C Dowd · R Higashida · V Halbach
    [Show abstract] [Hide abstract]
    ABSTRACT: Although many intracranial dural arteriovenous fistulas (DAVFs) are straightforward to treat, de novo and rapidly progressive ("runaway" or "malignant") DAVFs are more complex, often requiring multiple treatment sessions with suboptimal results. As these are rare entities, we sought to review our experience in the treatment of de novo and progressive DAVFs in order to better understand predictors of disease progression.
    Journal of Neurointerventional Surgery 07/2014; 6 Suppl 1:A47. DOI:10.1136/neurintsurg-2014-011343.88 · 2.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Arterial fenestrations are an anatomic variant with indeterminate significance. Given the controversy surrounding fenestrations we sought their prevalence within our practice along with their association with other cerebrovascular anomalies. We retrospectively reviewed 10,927 patients undergoing digital subtraction angiography between 1992 and 2011. Dictated reports were searched for the terms "fenestration" or "fenestrated" with images reviewed for relevance, yielding 228 unique cases. A Medline database search from February 1964 to January 2013 generated 304 citations, 127 cases of which were selected for analysis. Cerebral arterial fenestrations were identified in 228 patients (2.1%). At least one aneurysm was noted in 60.5% of patients, with an aneurysm arising from the fenestration in 19.6% of patients. Aneurysmal subarachnoid hemorrhage or non-aneurysmal subarachnoid hemorrhage were present in 60.1% and 15.8%, respectively. For the subset of patients with an aneurysm arising directly from a fenestration relative to those patients with an aneurysm not immediately associated with a fenestration, the prevalence of aneurysmal subarachnoid hemorrhage was 66.7% vs. 58.6% (p = 0.58). Fenestrations were more often within the posterior circulation (73.2%) than the anterior circulation (24.6%), though there was no difference in the prevalence of aneurysms within these groups (61.1% vs. 60.7%, p = 1.0). Cerebral arterial fenestrations are an anatomic variant more often manifesting at the anterior communicating arterial complex and basilar artery and with no definite pathological relationship with aneurysms.
    Interventional Neuroradiology 06/2014; 20(3):261-74. DOI:10.15274/INR-2014-10027 · 0.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Vein of Galen malformations (VOGMs) are rare and complex congenital arteriovenous fistulas. The clinical and radiological features of VOGMs and their relation to clinical outcomes are not fully characterized. To examine the clinical and radiological features of VOGMs and the predictors of outcome in patients. We retrospectively reviewed the available imaging and medical records of all patients with VOGMs treated at the University of California, San Francisco between 1986 and 2013. Radiological and clinical features were identified. We applied the modified Rankin Scale to determine functional outcome by chart review. Predictors of outcome were assessed by χ(2) analyses. Forty-one cases were confirmed as VOGM. Most patients (78%) had been diagnosed with VOGM in the first year of life. Age at treatment was bimodally distributed, with predominantly urgent embolization at <10 days of age and elective embolization after 1 year of age. Patients commonly presented with hydrocephalus (65.9%) and congestive heart failure (61.0%). Mixed-type (31.7%) VOGM was more common in our cohort than purely mural (29.3%) or choroidal (26.8%) types. The most common feeding arteries were the choroidal and posterior cerebral arteries. Transarterial embolization with coils was the most common technique used to treat VOGMs at our institution. Functional outcome was normal or only mildly disabled in 50% of the cases at last follow-up (median=3 years, range=0-23 years). Younger age at first diagnosis, congestive heart failure, and seizures were predictive of adverse clinical outcome. The survival rate in our sample was 78.0% and complete thrombosis of the VOGM was achieved in 62.5% of patients. VOGMs continue to be challenging to treat and manage. Nonetheless, endovascular approaches to treatment are continuing to be refined and improved, with increasing success. The neurodevelopmental outcomes of affected children whose VOGMs are treated may be good in many cases.
    Journal of Neurointerventional Surgery 04/2014; 7(6). DOI:10.1136/neurintsurg-2013-011005 · 2.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Different types of symptomatic intracranial stenosis may respond differently to interventional therapy. We investigated symptomatic and pathophysiologic factors that may influence clinical outcomes of patients with intracranial atherosclerotic disease who were treated with stents. A retrospective analysis was performed of patients treated with stents for intracranial atherosclerosis at 4 centers. Patient demographics and comorbidities, lesion features, treatment features, and preprocedural and postprocedural functional status were noted. χ(2) univariate and multivariate logistic regression analysis was performed to assess technical results and clinical outcomes. One hundred forty-two lesions in 131 patients were analyzed. Lesions causing hypoperfusion ischemic symptoms were associated with fewer strokes by last contact [χ(2) (1, n = 63) = 5.41, P = .019]. Nonhypoperfusion lesions causing symptoms during the 14 days before treatment had more strokes by last contact [χ(2) (1, n = 136), 4.21, P = .047]. Patients treated with stents designed for intracranial deployment were more likely to have had a stroke by last contact (OR, 4.63; P = .032), and patients treated with percutaneous balloon angioplasty in addition to deployment of a self-expanding stent were less likely to be stroke free at point of last contact (OR, 0.60; P = .034). More favorable outcomes may occur after stent placement for lesions causing hypoperfusion symptoms and when delaying stent placement 7-14 days after most recent symptoms for lesions suspected to cause embolic disease or perforator ischemia. Angioplasty performed in addition to self-expanding stent deployment may lead to worse outcomes, as may use of self-expanding stents rather than balloon-mounted stents.
    American Journal of Neuroradiology 03/2014; 35(6). DOI:10.3174/ajnr.A3836 · 3.59 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The imaging characteristics and modes of presentation of brain AVMs may vary with patient age. Our aim was to determine whether clinical and angioarchitectural features of brain AVMs differ between children and adults. A prospectively collected institutional data base of all patients diagnosed with brain AVMs since 2001 was queried. Demographic, clinical, and angioarchitecture information was summarized and analyzed with univariable and multivariable models. Results often differed when age was treated as a continuous variable as opposed to dividing subjects into children (18 years or younger; n = 203) versus adults (older than 18 years; n = 630). Children were more likely to present with AVM hemorrhage than adults (59% versus 41%, P < .001). Although AVMs with a larger nidus presented at younger ages (mean of 26.8 years for >6 cm compared with 37.1 years for <3 cm), this feature was not significantly different between children and adults (P = .069). Exclusively deep venous drainage was more common in younger subjects when age was treated continuously (P = .04) or dichotomized (P < .001). Venous ectasia was more common with increasing age (mean, 39.4 years with ectasia compared with 31.1 years without ectasia) and when adults were compared with children (52% versus 35%, P < .001). Patients with feeding artery aneurysms presented at a later average age (44.1 years) than those without such aneurysms (31.6 years); this observation persisted when comparing children with adults (13% versus 29%, P < .001). Although children with brain AVMs were more likely to come to clinical attention due to hemorrhage than adults, venous ectasia and feeding artery aneurysms were under-represented in children, suggesting that these particular high-risk features take time to develop.
    American Journal of Neuroradiology 03/2014; 35(7). DOI:10.3174/ajnr.A3886 · 3.59 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Stroke is the fourth-leading cause of death and a leading cause of long-term major disability in the United States. Measuring outcomes after stroke has important policy implications. The primary goals of this consensus statement are to (1) review statistical considerations when evaluating models that define hospital performance in providing stroke care; (2) discuss the benefits, limitations, and potential unintended consequences of using various outcome measures when evaluating the quality of ischemic stroke care at the hospital level; (3) summarize the evidence on the role of specific clinical and administrative variables, including patient preferences, in risk-adjusted models of ischemic stroke outcomes; (4) provide recommendations on the minimum list of variables that should be included in risk adjustment of ischemic stroke outcomes for comparisons of quality at the hospital level; and (5) provide recommendations for further research. This statement gives an overview of statistical considerations for the evaluation of hospital-level outcomes after stroke and provides a systematic review of the literature for the following outcome measures for ischemic stroke at 30 days: functional outcomes, mortality, and readmissions. Data on outcomes after stroke have primarily involved studies conducted at an individual patient level rather than a hospital level. On the basis of the available information, the following factors should be included in all hospital-level risk-adjustment models: age, sex, stroke severity, comorbid conditions, and vascular risk factors. Because stroke severity is the most important prognostic factor for individual patients and appears to be a significant predictor of hospital-level performance for 30-day mortality, inclusion of a stroke severity measure in risk-adjustment models for 30-day outcome measures is recommended. Risk-adjustment models that do not include stroke severity or other recommended variables must provide comparable classification of hospital performance as models that include these variables. Stroke severity and other variables that are included in risk-adjustment models should be standardized across sites, so that their reliability and accuracy are equivalent. There is a pressing need for research in multiple areas to better identify methods and metrics to evaluate outcomes of stroke care. There are a number of important methodological challenges in undertaking risk-adjusted outcome comparisons to assess the quality of stroke care in different hospitals. It is important for stakeholders to recognize these challenges and for there to be a concerted approach to improving the methods for quality assessment and improvement.
    Stroke 03/2014; 45(3):918-44. DOI:10.1161/01.str.0000441948.35804.77 · 5.72 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Contrast staining of brain parenchyma identified on non-contrast CT performed after DSA in patients with acute ischemic stroke (AIS) is an incompletely understood imaging finding. We hypothesize contrast staining to be an indicator of brain injury and suspect the fate of involved parenchyma to be cerebral infarction. Seventeen years of AIS data were retrospectively analyzed for contrast staining. Charts were reviewed and outcomes of the stained parenchyma were identified on subsequent CT and MRI. Thirty-six of 67 patients meeting inclusion criteria (53.7%) had contrast staining on CT obtained within 72 hours after DSA. Brain parenchyma with contrast staining in patients with AIS most often evolved into cerebral infarction (81%). Hemorrhagic transformation was less likely in cases with staining compared with hemorrhagic transformation in the cohort that did not have contrast staining of the parenchyma on post DSA CT (6% versus 25%, respectively, OR 0.17, 95% CI 0.017 - 0.98, p = 0.02). Brain parenchyma with contrast staining on CT after DSA in AIS patients was likely to infarct and unlikely to hemorrhage.
    Interventional Neuroradiology 02/2014; 20(1):106-15. DOI:10.15274/INR-2014-10016 · 0.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Retinoblastoma (RB) is a rare malignancy affecting the pediatric population. Intravenous chemotherapy is the longstanding delivery method, although intra-arterial (IA) chemotherapy is gaining popularity given the reduced side effects compared with systemic chemotherapy administration. Given the sensitivity of the target organ, patient age, and secondary tumor susceptibility, a premium has been placed on minimizing procedural related radiation exposure. To reduce patient x-ray dose during the IA infusion procedure, customized surgical methods and fluoroscopic techniques were employed. The routine fluoroscopic settings were changed from the standard 7.5 pulses/s and dose level to the detector of 36 nGy/pulse, to a pulse rate of 4 pulses/s and detector dose to 23 nGy/pulse. The angiographic dose indicators (reference point air kerma (Ka) and fluoroscopy time) for a cohort of 10 consecutive patients (12 eyes, 30 infusions) were analyzed. An additional four cases (five eyes, five infusions) were analyzed using dosimeters placed at anatomic locations to reflect scalp, eye, and thyroid dose. The mean Ka per treated eye was 20.1±11.9 mGy with a mean fluoroscopic time of 8.5±4.6 min. Dosimetric measurements demonstrated minimal dose to the lens (0.18±0.10 mGy). Measured entrance skin doses varied from 0.7 to 7.0 mGy and were 73.4±19.7% less than the indicated Ka value. Ophthalmic arterial melphalan infusion is a safe and effective means to treat RB. Modification to contemporary fluoroscopic systems combined with parsimonious fluoroscopy can minimize radiation exposure.
    Journal of Neurointerventional Surgery 01/2014; 6(10). DOI:10.1136/neurintsurg-2013-010905 · 2.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background The clinical benefit of preventive eradication of unruptured brain arteriovenous malformations remains uncertain. A Randomised trial of Unruptured Brain Arteriovenous malformations (ARUBA) aims to compare the risk of death and symptomatic stroke in patients with an unruptured brain arteriovenous malformation who are allocated to either medical management alone or medical management with interventional therapy. Methods Adult patients (≥18 years) with an unruptured brain arteriovenous malformation were enrolled into this trial at 39 clinical sites in nine countries. Patients were randomised (by web-based system, in a 1:1 ratio, with random permuted block design [block size 2, 4, or 6], stratified by clinical site) to medical management with interventional therapy (ie, neurosurgery, embolisation, or stereotactic radiotherapy, alone or in combination) or medical management alone (ie, pharmacological therapy for neurological symptoms as needed). Patients, clinicians, and investigators are aware of treatment assignment. The primary outcome is time to the composite endpoint of death or symptomatic stroke; the primary analysis is by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00389181. Findings Randomisation was started on April 4, 2007, and was stopped on April 15, 2013, when a data and safety monitoring board appointed by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health recommended halting randomisation because of superiority of the medical management group (log-rank Z statistic of 4·10, exceeding the prespecified stopping boundary value of 2·87). At this point, outcome data were available for 223 patients (mean follow-up 33·3 months [SD 19·7]), 114 assigned to interventional therapy and 109 to medical management. The primary endpoint had been reached by 11 (10·1%) patients in the medical management group compared with 35 (30·7%) in the interventional therapy group. The risk of death or stroke was significantly lower in the medical management group than in the interventional therapy group (hazard ratio 0·27, 95% CI 0·14–0·54). No harms were identified, other than a higher number of strokes (45 vs 12, p<0·0001) and neurological deficits unrelated to stroke (14 vs 1, p=0·0008) in patients allocated to interventional therapy compared with medical management. Interpretation The ARUBA trial showed that medical management alone is superior to medical management with interventional therapy for the prevention of death or stroke in patients with unruptured brain arteriovenous malformations followed up for 33 months. The trial is continuing its observational phase to establish whether the disparities will persist over an additional 5 years of follow-up. Funding National Institutes of Health, National Institute of Neurological Disorders and Stroke.
    The Lancet 01/2014; 383(9917):614–621. · 45.22 Impact Factor

Publication Stats

19k Citations
1,633.54 Total Impact Points


  • 1987–2015
    • University of California, San Francisco
      • • Department of Radiology and Biomedical Imaging
      • • Department of Neurological Surgery
      • • Department of Neurology
      • • Department of Clinical Pharmacy
      • • Division of Hospital Medicine
      San Francisco, California, United States
    • Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center
      Torrance, California, United States
    • University of California, Irvine
      • Department of Surgery
      Irvine, California, United States
  • 2013
    • St. Michael's Hospital
      Toronto, Ontario, Canada
  • 2011
    • New York Presbyterian Hospital
      • Department of Radiology
      New York City, New York, United States
  • 2010
    • Royal North Shore Hospital
      Sydney, New South Wales, Australia
  • 1993–2010
    • San Francisco VA Medical Center
      San Francisco, California, United States
  • 2006
    • The Ohio State University
      • Department of Neurological Surgery
      Columbus, OH, United States
    • Columbia University
      New York, New York, United States
  • 2004
    • Cornell University
      Ithaca, New York, United States
    • Barrow Neurological Institute
      Phoenix, Arizona, United States
  • 2003
    • Baptist Hospital
      Nashville, Tennessee, United States
  • 2000
    • Royal Perth Hospital
      Perth City, Western Australia, Australia
  • 1996
    • Wakayama Medical University
      Wakayama, Wakayama, Japan
  • 1994
    • Baylor University
      Waco, Texas, United States
  • 1986–1992
    • University of Missouri - Kansas City
      • Department of Radiology
      Kansas City, Missouri, United States
  • 1989
    • Fukuoka University
      • Department of Radiology
      Hukuoka, Fukuoka, Japan