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PURPOSE: In this international multispecialty document, quality benchmarks for processes of care and clinical outcomes are defined. It is intended that these benchmarks be used in a quality assurance program to assess and improve processes and outcomes in acute stroke revascularization. MATERIALS AND METHODS: Members of the writing group were appointed by the American Society of Neuroradiology, Canadian Interventional Radiology Association, Cardiovascular and Interventional Radiological Society of Europe, Society of Cardiac Angiography and Interventions, Society of Interventional Radiology, Society of Neuro Interventional Surgery, European Society of Minimally Invasive Neurological Therapy, and Society of Vascular and Interventional Neurology. The writing group reviewed the relevant literature from 1986 through February 2012 to create an evidence table summarizing processes and outcomes of care. Performance metrics and thresholds were then created by consensus. The guideline was approved by the sponsoring societies. It is intended that this guideline be fully updated in 3 years. RESULTS: In this international multispecialty document, quality benchmarks for processes of care and clinical outcomes are defined. These include process measures of time to imaging, arterial puncture, and revascularization and measures of clinical outcome up to 90 days. CONCLUSIONS: Quality improvement guidelines are provided for endovascular acute ischemic stroke revascularization procedures.

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PURPOSE: In this international multispecialty document, quality benchmarks for processes of care and clinical outcomes are defined. It is intended that these benchmarks be used in a quality assurance program to assess and improve processes and outcomes in acute stroke revascularization. MATERIALS AND METHODS: Members of the writing group were appointed by the American Society of Neuroradiology, Canadian Interventional Radiology Association, Cardiovascular and Interventional Radiological Society of Europe, Society of Cardiac Angiography and Interventions, Society of Interventional Radiology, Society of NeuroInterventional Surgery, European Society of Minimally Invasive Neurological Therapy, and Society of Vascular and Interventional Neurology. The writing group reviewed the relevant literature from 1986 through February 2012 to create an evidence table summarizing processes and outcomes of care. Performance metrics and thresholds were then created by consensus. The guideline was approved by the sponsoring societies. It is intended that this guideline be fully updated in 3 years. RESULTS: In this international multispecialty document, quality benchmarks for processes of care and clinical outcomes are defined. These include process measures of time to imaging, arterial puncture, and revascularization and measures of clinical outcome up to 90 days. CONCLUSIONS: Quality improvement guidelines are provided for endovascular acute ischemic stroke revascularization procedures.

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PURPOSE: In this international multispecialty document, quality benchmarks for processes of care and clinical outcomes are defined. It is intended that these benchmarks be used in a quality assurance program to assess and improve processes and outcomes in acute stroke revascularization. MATERIALS AND METHODS: Members of the writing group were appointed by the American Society of Neuroradiology, Canadian Interventional Radiology Association, Cardiovascular and Interventional Radiological Society of Europe, Society of Cardiac Angiography and Interventions, Society of Interventional Radiology, Society of NeuroInterventional Surgery, European Society of Minimally Invasive Neurological Therapy, and Society of Vascular and Interventional Neurology. The writing group reviewed the relevant literature from 1986 through February 2012 to create an evidence table summarizing processes and outcomes of care. Performance metrics and thresholds were then created by consensus. The guideline was approved by the sponsoring societies. It is intended that this guideline be fully updated in 3 years. RESULTS: In this international multispecialty document, quality benchmarks for processes of care and clinical outcomes are defined. These include process measures of time to imaging, arterial puncture, and revascularization and measures of clinical outcome up to 90 days. CONCLUSIONS: Quality improvement guidelines are provided for endovascular acute ischemic stroke revascularization procedures.

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Arteriovenous malformations (AVMs) of the scalp are rare congenital lesions that can be extremely disfiguring and even life-threatening. Another congenital lesion is the preauricular sinus, which forms when the auricular hillocks fail to fuse. We present a case of an AVM of the scalp that ruptured into a preauricular sinus. The occurrence of these two lesions on the same side of a patient is a notable and previously unreported event. The patient was successfully treated with intravascular embolization and surgical ligation.

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Traumatic injury to the major vessels of the head and neck can result in potentially devastating neurologic sequelae. Until recently, conventional angiography was the primary imaging modality used to evaluate these often challenging patients. Advances in cross-sectional imaging have improved the ability to screen for these lesions, which have been found to be more common than previously thought; however, accepted protocols of imaging evaluation have not yet been fully established. This article presents a general approach to the patient with suspected neurovascular injury. This includes a discussion of the histopathologic spectrum, clinical presentation, mechanisms, radiologic work-up, pertinent issues of the most common lesions, and some of the endovascular techniques used in their management.

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BACKGROUND: Direct thrombin inhibitors, a class of anticoagulants distinct from heparins, have not been evaluated for immediate use after thrombolytic therapy in acute ischemic stroke. We report a case of ischemic stroke and prothrombotic state treated using sequenced intravenous and intra-arterial thrombolytic therapy and argatroban anticoagulation. CASE DESCRIPTION: A 19-year-old man with a complicated history of recurrent life-threatening thrombosis presented at the emergency department with acute ischemic stroke. The patient received standard-dose intravenous alteplase starting 2.25 hours after symptom onset without change in his global aphasia and right hemiparesis. Five hours after symptom onset, intra-arterial reteplase was administered for treatment of a left internal carotid "T" occlusion, with successful recanalization of the left internal carotid artery, A1 and M1 segments, and right middle cerebral anterior division and with improvement in symptoms. Argatroban therapy was started after completion of intra-arterial thrombolysis, i.e., 8.5 hours after symptom onset, and was maintained for 14 days. Although the patient sustained a small left basal ganglia infarct, he improved significantly over the course of therapy and was discharged to home without bleeding or further thrombotic episodes. CONCLUSIONS: Sequenced intravenous and intra-arterial thrombolytic therapy and argatroban anticoagulation was used successfully to safely treat a patient with ischemic stroke and comorbid prothrombotic state within 8.5 hours of symptom onset.

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Percutaneous vertebroplasty has emerged as an effective technique for treatment of painful vertebral compression fractures (VCFs) caused by osteoporosis, malignancy, and some benign bone tumors. In selecting appropriate patients for vertebroplasty, it is important to distinguish the pain caused by VCF from other numerous causes of back pain. Careful adherence to clinical and imaging selection criteria is crucial to procedural success.

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PURPOSE: Osteoporotic vertebral compression fractures may cause debilitating pain that lasts for weeks or months, and which is often neither quickly nor completely relieved by conventional conservative therapy. Previous retrospective studies have suggested significant and nearly immediate pain relief, as well as rapid and sustained functional recovery, after percutaneous polymethylmethacrylate vertebroplasty (PPV). This prospective, quantitative study with long-term follow-up was designed to evaluate the safety and efficacy of PPV as a new treatment for patients with osteoporotic vertebral body compression fractures of the lumbar and thoracic spine. MATERIALS AND METHODS: PPV was performed in 30 patients with 54 symptomatic osteoporotic vertebral compression fractures who had a less-than-satisfactory response to conventional therapy. All procedures were performed by a single operator with significant experience in performing PPV. The Musculoskeletal Outcomes Data Evaluation and Management Scale (MODEMS) spinal intervention questionnaire, which includes the SF-36, was administered to all patients before intervention and exactly 2 weeks after the final PPV procedure. Pain and disability, treatment expectations and satisfaction, mental function, and quality of life were evaluated by four specialized modules, and responses to questionnaires preceding treatment were compared to those obtained at follow-up. Results of a long-term follow-up questionnaire were collected 15-18 months after the final vertebroplasty treatment. RESULTS: Our population consisted of three men and 27 women, with a mean age of 79 years. Fifty-four PPV procedures were performed for compression fractures in these 30 patients. Significant postprocedural improvement in all four MODEMS modules was demonstrated at 2 weeks (treatment score, P <.0001; pain and disability, P <.0001; physical function, P =.0004; and mental function, P =.0009). A small epidural leak of polymethylmethacrylate in one patient was asymptomatic and did not require intervention. At long-term follow-up (15-18 mo), 22 of 23 patients responding remained satisfied with the outcome of therapy and believed that the procedure had provided durable pain relief. Verbal pain scores documented significantly diminished back pain at 2 weeks (P <.0001) and again at long-term follow-up when compared to baseline (P <.0001). CONCLUSIONS: PPV is a safe and efficacious procedure for the relief of pain and disability after osteoporotic vertebral compression fractures. Patient satisfaction is high and persists when compared to preprocedural expectations; durable pain relief is provided.

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Facet and sacroiliac joint pathology are not an uncommon cause of back or neck pain. Imaging-guided techniques provide ready access to these synovial joints. Percutaneous injection of the facet or sacroiliac joints yields important diagnostic information as to whether or not the interrogated joint is involved in the patient's pain syndrome. The injection of a steroid-anesthetic mixture into these joints is capable of providing significant, albeit temporary, pain relief.

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Percutaneous vertebroplasty has been performed in the United States since 1995, and widespread application of the procedure for osteoporotic and neoplastic compression fractures or vertebral infiltration has demonstrated remarkable efficacy with rare complications. Appropriate patient selection criteria and a thorough understanding of safe technique is essential for clinical success; imaging studies must be combined with careful physical examination to direct treatment to the appropriate level in patients with multiple compression deformities. Preoperative consultation with the patient and their family provides an opportunity to clarify the patient's treatment expectations and helps to anticipate and obviate potential obstacles to treatment.

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The hippocampal formation possesses an important role in the development and maintenance of short-term memory. In this study, magnetic resonance imaging (MRI) and gross histology were used to quantify the volume of the hippocampal formation in canines. High resolution MRI, using 1 mm thick slices and an intraplanar resolution of 0.35 mm was performed at 2.0 T both in vivo and in vitro following in situ fixation. The volumes of the hippocampal formations were determined from MR images and compared to those obtained from one mm thick gross histologic sections. The average volume of the canine hippocampal formation, measured from in vivo and in vitro MR images was 476.0 +/- 79.5 and 467.3 +/- 53.7 mm3, respectively. Determined from gross histology, the volume of the hippocampal formation was 463.6 +/- 24.1 mm3. Quantitation of the canine hippocampal formation using in vivo MRI showed good correlation with in vitro MRI and histology, verifying the reliability and reproducibility of in vivo MRI measurements. High resolution MRI using 1 mm thick slices through the whole canine hippocampal formation is necessary for accurate volume determination of a structure of this size.

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Although magnetic resonance imaging (MRI) is a valuable aid in the initial diagnosis of multiple sclerosis (MS), quantitatively MRI has been disappointing in staging and evaluating therapy protocols by means of serial examinations. In this study, image processing algorithms were developed for the global analysis of MR images of the cerebrum. Limited three-dimensional segmentation was achieved through histogram analysis by these algorithms, which are essentially operator independent. The effects of coil response and tip angles, patient positioning, and interslice gap thicknesses were examined for 10 MS patients with repeated examinations for a total of 72 images. Effects of technique and instrumentation errors were approximately 6%, and agreement between two independent operators for measuring the total MR pixel sum from periventricular effusions and intense MS plaques was better than 97% with a standard deviation of 2.9%.

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The Salmonella typhimurium basal body, a part of the flagellar rotary motor, consists of four rings (denoted M, S, P and L) and a coaxial rod. Using low-dose electron microscopy and image averaging methods on negatively stained and frozen-hydrated preparations, we examined whole basal body complexes and subcomplexes obtained by dissociation in acid. Dissociation occurs in steps, allowing us to obtain images of substructures lacking the M ring, lacking the M and S rings, and lacking the M and S rings and the proximal portion of the rod. We obtained images of the L and P ring subcomplex. The existence of a subcomplex missing only the M ring suggests either that the S and M rings derive from two different proteins, or that the M ring is a labile domain of a single protein, which makes up both rings. At the 25 to 30 A resolution of our averaged images, the L, P and S rings appear cylindrically symmetric. Images of the M ring show variability that may be due to differences in angular orientation of the grid, but equally could be due to structural variations. Three-dimensional reconstructions of these structures from the averaged images reveal the internal structure and spatial organization of these components.

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The bacterium Caulobacter crescentus has a single polar flagellum, which is present for only a portion of its cell cycle. The flagellum is ejected from the swarmer cell and then synthesized de novo later in the cell cycle. The flagellum is composed of a transmembrane basal body, a hook and a filament. Single-particle averaging and image reconstruction methods were applied to the electron micrographs of negatively stained basal bodies from C. crescentus. These basal bodies have five rings threaded on a rod. The L and P rings are connected by a bridge of material at their outer radii. The E ring is a thin, flat disk. The S ring has a triangular cross section, the sides of the triangle abutting the E ring, the rod and the M ring. The M ring, which is at the inner membrane of the cell, has a different structure depending on the method of preparation. With one method, the M ring makes a snug contact with the S ring and is often capped by an axial button, a new component apparently distinct from the M ring. With the other method, the M ring is similar to that of S. typhimurium; that is, it contacts the S ring only at an outer radius and lacks the button. Averages of the rod-hook-filament subassembly ejected by swarmer cells reveal that the rod consists of two parts with the E ring marking the approximate position of the break. The structures of basal bodies from two mutants defective in the hook assembly were found to be indistinguishable from wild-type basal bodies, suggesting that the assembly of the basal body is independent of the hook or filament assembly.

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The basal body is thought to be a part of the rotary motor of the bacterial flagellum. It consists of a central rod coaxial with a set of four rings, which are associated with the cell envelope. We used single-particle averaging methods to analyze images of negatively stained basal bodies of Salmonella typhimurium. Several averages were computed, so that the reliability of features could be assessed. We carried out the same analysis on electron micrographs of isolated, negatively stained L-P rings. In order to interpret the averages in terms of a three-dimensional structure, we carried out image reconstruction on them. The resulting three-dimensional map corresponds to the cylindrically averaged structure of the basal body. To show that the reconstruction procedure is legitimate, we demonstrate it on model data. The results of the modelling show that features very near to the axis of the reconstruction are not reliable but that broader, off-axis features are represented faithfully. The L ring is L-shaped, with the long arm of the L parallel to the axis of the rod, and the short arm pointing away from the rod. The P ring, on the other hand, appears to be a ring or disk. The position of the L-P ring complex on the rod seems to vary somewhat, consistent with its putative role as a bushing. The cross-sectional shape of the S ring is that of a frustum rather than a disk. The M ring, which is oval in cross section, sits atop the S ring, making contact with it at an outer radius. The S ring appears to make contact with the rod, whereas the M ring does not. This situation, if true, is difficult to reconcile with the common notion that the S ring is stationary and the M ring rotates. It seems more likely that the S ring and rod rotate as a unit.

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