Daniel L. Cooke

Density of Thrombus on Admission CT Predicts Revascularization Efficacy in Large Vessel Occlusion Acute Ischemic Stroke

Background and Purpose— Can lysability of large vessel thrombi in acute ischemic stroke be predicted by measuring clot density on admission nonenhanced CT (NECT), postcontrast enhanced CT, or CT angiogram (CTA)? Methods— We retrospectively studied 90 patients with acute large vessel ischemic strokes treated with intravenous (IV) tPA, intra-arterial (IA) tPA, and/or mechanical thrombectomy devices. Clot density [in Hounsfield unit (HU)] was measured on NECT, postcontrast enhanced CT, and CTA. Recanalization was assessed by the Thrombolysis in Cerebral Infarction grading system (TICI) on digital subtraction angiography. Results— Thrombus density on preintervention NECT correlated with postintervention TICI grade regardless of pharmacological (IV tPA r=0.69, IA tPA r=0.72, P<0.0001) or mechanical treatment (r=0.73, P<0.0001). Patients with TICI≥2 demonstrated higher HU on NECT (mean corrected HU IV tPA=1.58, IA tPA=1.66, mechanical treatment=1.7) compared with patients with TICI<2 (IV tPA=1.39, IA tPA=1.4, mechanical treatment=1.3) (P=0.01, 0.006, <0.0001 respectively). There was no association between recanalization and age, sex, baseline National Institute of Health Stroke Scale, treatment method, time to treatment, or clot volume. Conclusions— Thrombi with lower HU on NECT appear to be more resistant to pharmacological lysis and mechanical thrombectomy. Measuring thrombus density on admission NECT provides a rapid method to analyze clot composition, a potentially useful discriminator in selecting the most appropriate reperfusion strategy for an individual patient.

Retrospective Analysis of Preoperative Embolization of Spinal Tumors

BACKGROUND AND PURPOSE: Preoperative embolization of primary and metastatic spinal tumors is often performed to decrease intraoperative blood loss and facilitate surgical resection. The purpose of this study was to evaluate the safety of spinal tumor embolization and the variables that may influence intraoperative blood loss. MATERIALS AND METHODS: A retrospective analysis of 100 spinal tumor embolization procedures was performed. Multiple variables were evaluated with respect to intraoperative blood loss, including tumor pathology, degree of tumor embolization, embolization above/below the levels involved, PVA particle size, surgical approach, and invasiveness. RESULTS: There was 1 significant complication of the 100 embolization procedures performed. Evaluation of the entire set of embolization procedures demonstrated that RCC was associated with increased intraoperative blood loss (P = .009) relative to other tumor types, as were the surgical approach and invasiveness of the surgery performed. No other variables were found to be statistically significant predictors of intraoperative blood loss. Subset analysis of all RCCs demonstrated that complete embolization resulted in decreased blood loss compared with partial embolization (P = .03) and that male sex was associated with increased blood loss (P = .029). CONCLUSIONS: Preoperative embolization of spinal tumors is a safe procedure. Complete embolization of RCCs results in lower intraoperative blood loss compared with partial embolization. The effectiveness of preoperative embolization of non-RCCs is unclear. Using smaller embolic particles and embolizing beyond the levels affected by tumor may not provide added benefit.

Influence of patient age on angioarchitecture of brain arteriovenous malformations.

Over 800 AVMs were retrospectively reviewed to determine if clinical and angioarchitectural features varied between children and adults. The authors found that hemorrhages and exclusively deep venous drainage were more common in children but high-risk features such as venous ectasia and feeding artery aneurysm were more common in adults. Thus, these latter high-risk features may take time to develop. BACKGROUND AND PURPOSE: 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. MATERIALS AND METHODS: 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: 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). CONCLUSIONS: 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.

Superselective intra-arterial melphalan therapy for newly diagnosed and refractory retinoblastoma: results from a single institution.

Background: Intra-arterial administration of melphalan chemotherapy has shown promise in the treatment of retinoblastoma. This report describes our results using superselective intra-arterial melphalan in patients with newly diagnosed retinoblastoma and those who were treated for progression after systemic chemotherapy. Methods: This is a retrospective review of all retinoblastoma patients treated with intra-arterial melphalan at the University of California, San Francisco from March 2010 to August 2012. Twenty eyes (16 patients) underwent 40 intra-arterial melphalan infusions, and dose was determined by age. Patients were treated at monthly intervals and received a range of 1–5 treatments. Response to therapy, toxicity, and procedural radiation exposure was assessed. Results: All patients are alive without metastatic disease at a median follow-up of 14.5 (1–29) months. Treatment with enucleation or external beam radiation was avoided in 11/20 eyes (55%) overall [6/12 (50%) in newly diagnosed eyes and 5/8 (63%) in refractory/relapsed eyes]. Response rates (per the International Classification of Retinoblastoma) were as follows: 6/7 (86%) in groups A–C and 5/13 (38%) in groups D and E. Nonhematologic and hematologic toxicities were minimal and comparable with those in previous reports. The mean procedural radiation dose was 20.2 ± 11.9 mGy per eye per procedure. Conclusion: Superselective intra-arterial melphalan therapy is effective for less advanced eyes but further modifications to therapy are required to improve results in eyes with advanced retinoblastoma.

Mechanical embolectomy for treatment of large vessel acute ischemic stroke in children.

Background and purpose The three largest adult stroke trials investigating mechanical embolectomy retrieval devices in acute stroke (the Merci, Multi Merci and Penumbra Pivotal Stroke Trials) excluded children. There is a need to expand the literature on mechanical embolectomy in large vessel pediatric arterial ischemic stroke. This paper reports the use of two mechanical embolectomy devices cleared by the Federal Drug Administration (FDA) in four consecutive cases. Methods Our pediatric stroke database from 2002 to the present was reviewed retrospectively. Patients were included if they were diagnosed with an acute large vessel occlusion, were <18 years of age and underwent recanalization with a device cleared by the FDA. Clinical and radiographic results were abstracted from medical record review. The Pediatric National Institutes of Health Stroke Scale (PedNIHSS) score at presentation and at discharge and a pediatric-modified Rankin Scale (Ped-mRS) at approximately 90 days were scored retrospectively based on documented examinations. Results Four patients aged 4–17 years with a PedNIHSS score at presentation ranging from 2 to 17 points underwent mechanical embolectomy for reperfusion of the basilar artery (n=3), M1 segment of the right middle cerebral artery (n=1) and right internal carotid artery terminus (n=1). Thrombolysis in cerebral infarction (TICI) grade 3 was achieved in four vessels and TICI grade 2A was achieved in one vessel; there was one asymptomatic intraparenchymal hemorrhage. Intra-arterial tissue plasminogen activator was administered in two vessels. The PedNIHSS score at discharge ranged from 0 to 16 points and the Ped-mRS score at approximately 90 days ranged from 0 to 3 with 75% achieving a Ped-mRS score of ≤2. Conclusion Mechanical embolectomy using the Merci and Penumbra systems may be a feasible therapeutic option in the treatment of large vessel pediatric arterial ischemic stroke.

Current trends in endovascular management of traumatic cerebrovascular injury

Background The role of catheter angiography in the diagnosis and management of traumatic cerebrovascular injury has evolved rapidly with advances in CT and MR angiography and continued development of endovascular techniques. Objective To identify the modern spectrum of traumatic arterial injury encountered during catheter neuroangiography and to examine current patterns of endovascular treatment. Methods Records of trauma patients undergoing catheter neuroangiography over a 4 year period at two high volume centers were retrospectively reviewed. The sample comprised 100 separate arterial lesions that were classified according to mechanism, location, acuity, and endovascular treatment. Follow-up imaging and clinical notes were reviewed to identify procedural complications. Results Of 100 arterial lesions, 81% were related to blunt trauma. Distribution of lesions by location was 42% intracranial, 39% cervical, and 19% extracranial. The most common injuries were pseudoaneurysm (38%), fistula (29%), and dissection (19%). In total, 41% of lesions underwent endovascular treatment, with trends favoring treatment of non-acute, penetrating, non-cervical, and high grade lesions. Therapy involved coil embolization for 89% of treated lesions. There were a total of two immediate neurovascular complications and one delayed neurovascular complication; one of these resulted in a permanent neurological deficit. Conclusions Our experience in a large cohort of patients suggests that a relatively high proportion of traumatic arterial lesions identified by catheter angiography are treated by endovascular means, with a low rate of immediate and delayed neurovascular complications.

Transvenous embolization of a pediatric pial arteriovenous fistula

Pial arteriovenous fistulas (AVFs) are a rare, although clinically significant, vascular anomaly affecting the pediatric population. There are few retrospective case series describing their epidemiological, clinical and radiographic characteristics as well as technical elements of treatment. Combined transarterial and transvenous embolization of a 12 month old female with a multi-hole pial AVF is described. The patient underwent treatment in a staged fashion and without neurological complication.

Serial angiographic appearance of segmental arterial mediolysis manifesting as vertebral, internal mammary and intra-abdominal visceral artery aneurysms in a patient presenting with subarachnoid hemorrhage and review of the literature

Segmental arterial mediolysis (SAM) is a rare, non-inflammatory, non-atherosclerotic vasculopathy typically affecting the abdominal arteries although it may also affect the great vessels and cerebral vasculature. Diseased vessels manifest with aneurysms and/or dissections, often presenting clinically with catastrophic thromboembolic injury and less frequently with subarachnoid hemorrhage (SAH). The etiology of SAM remains indeterminate although there is evidence it may be an endogenous pathological response to vasospasm. The SAM literature is reviewed and a case of SAH related to a ruptured dissecting-type vertebral artery aneurysm is described. In addition to furthering awareness of SAM, this unique case offers insight into the acute phase of the disease and the potential role of vasospastic induction.

Transcranial Access Using Fluoroscopic Flat Panel Detector CT Navigation

SUMMARY: FPCT and navigation software on contemporary fluoroscopic units perform imaging of a quality comparable with conventional CT. They can accurately guide percutaneous procedures, providing live instrument visualization and the capability to re-image without patient transfer. FPCT navigation was used in the placement of a ventricular drain in a 62-year-old woman for subarachnoid-related hydrocephalus by using an otherwise standard bedside technique. Ventriculostomy catheter placement was technically successful without complication with a catheter at the foramen of Monro.

Contrast staining on CT after DSA in ischemic stroke patients progresses to infarction and rarely hemorrhages.

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.