Search

Retractors and scopes used in head and neck surgery to provide adequate surgical exposure also deform critical structures in the region. Surgeons typically use preoperative imaging to plan and guide their tumor resections, however the large tissue deformation resulting from placement of retractors and scopes reduces the utility of preoperative imaging as a reliable roadmap. We quantify the extent of tumor and vasculature deformation in patients with tumors of the larynx and pharynx undergoing diagnostic laryngoscopy. A mean tumor displacement of 1.02 cm was observed between the patients’ pre- and intra-operative states. Mean vasculature displacement at key bifurcation points was 0.99 cm. Registration to the hyoid bone can reduce tumor displacement to 0.67 cm and improve carotid stem angle deviations but increase overall vasculature displacement. The large deformation results suggest limitations in reliance on preoperative imaging and that using specific landmarks intraoperatively or having more intraoperative information could help to compensate for these deviations and ultimately improve surgical success.

Increased oxygen levels may enhance the radiosensitivity of brain metastases treated with stereotactic radiosurgery (SRS). This project administered hyperbaric oxygen (HBO) prior to SRS to assess feasibility, safety, and response.38 patients were studied, 19 with 25 brain metastases treated with HBO prior to SRS, and 19 historical controls with 27 metastases, matched for histology, GPA, resection status, and lesion size. Outcomes included time from HBO to SRS, quality-of-life (QOL) measures, local control, distant (brain) metastases, radionecrosis, and overall survival.The average time from HBO chamber to SRS beam-on was 8.3 ± 1.7 minutes. Solicited adverse events (AEs) were comparable between HBO and control patients; no grade III or IV serious AEs were observed. Radionecrosis-free survival (RNFS), radionecrosis-free survival before whole-brain radiation therapy (WBRT) (RNBWFS), local recurrence-free survival before WBRT (LRBWFS), distant recurrence-free survival before WBRT (DRBWFS), and overall survival (OS) were not significantly different for HBO patients and controls on Kaplan-Meier analysis, though at 1-year estimated survival rates trended in favor of SRS + HBO: RNFS - 83% vs 60%; RNBWFS - 78% vs 60%; LRBWFS - 95% vs 78%; DRBWFS - 61% vs 57%; and OS - 73% vs 56%. Multivariate Cox models indicated no significant association between HBO treatment and hazards of RN, local or distant recurrence, or mortality; however, these did show statistically significant associations (p 0.05) for: local recurrence with higher volume, radionecrosis with tumor resection, overall survival with resection, and overall survival with higher GPA.Addition of HBO to SRS for brain metastases is feasible without evident decrement in radiation necrosis and other clinical outcomes.

BackgroundDuring the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study’s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines.MethodsWe conducted a cross-sectional, retrospective, observational study across 6 continents, 37 countries and 140 comprehensive stroke centres. Patients with the diagnosis of SAH, aneurysmal SAH, ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases, 10th Revision, codes. The 3-month cumulative volume, monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before (1 year and immediately before) and during the pandemic, defined as 1 March–31 May 2020. The prior 1-year control period (1 March–31 May 2019) was obtained to account for seasonal variation.FindingsThere was a significant decline in SAH hospitalisations, with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic, representing a relative decline of 22.5% (95% CI −24.3% to −20.7%, pInterpretationThere was a relative decrease in the volume of SAH hospitalisations, aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 pandemic. These findings in SAH are consistent with a decrease in other emergencies, such as stroke and myocardial infarction.

To evaluate clinical outcomes following percutaneous rupture of symptomatic lumbar facet synovial cysts (LFSCs) with intra-articular steroid injection.In this retrospective review, 44 consecutive patients with symptomatic LFSCs received primary treatment with CT-guided synovial cyst rupture with intra-articular steroid injection. Outcomes questionnaires were obtained before and 1, 4, 26, and 52 weeks after LFSC rupture. Assessment included pain medication use and numeric rating scale (NRS), Oswestry Disability Index (ODI), and 12-item short form health survey (SF-12) physical and mental composite scores (PCS and MCS). Clinical endpoint was 52-week survey response or surgery.LFSC rupture was technically successful in 84% (37/44) of cases. Clinical endpoint was reached in 68% (30/44) of patients with 82% overall 1-year follow-up. Lumbar spine surgery was performed in 25% (11/44) of patients within 1 year after procedure. Mean NRS, ODI, and SF-12 PCS demonstrated significant improvement at all follow-up time points (P.001). At 52-week follow-up, NRS decreased from 8.1 to 3.7 (P.001), ODI improved from 35 to 24 (P = .006), and SF-12 PCS improved from 31 to 42 (P.001). Daily pain medication decreased from 71% (31/44) of patients before procedure to 29% (9/26) at 52-week follow-up (P = .012). History of prior lumbar intervention was associated with poorer LFSC rupture success (P = .025) and ODI (P = .047).NRS, ODI, and SF-12 PCS indices improved and pain medication use decreased significantly at all time points over 1-year follow-up after percutaneous rupture of symptomatic LFSCs with intra-articular steroid injection.

Cerebral tissue oxygenation (oxygen tension, pO2) is a critical parameter that is closely linked to brain metabolism, function, and pathophysiology. In this work, we have used electron paramagnetic resonance oximetry with a deep-tissue multi-site oxygen-sensing probe, called implantable resonator, to monitor temporal changes in cerebral pO2 simultaneously at four sites in a rabbit model of ischemic stroke induced by embolic clot. The pO2 values in healthy brain were not significantly different among the four sites measured over a period of 4 weeks. During exposure to 15% O2 (hypoxia), a sudden and significant decrease in pO2 was observed in all four sites. On the other hand, brief exposure to breathing carbogen gas (95% O2 + 5% CO2) showed a significant increase in the cerebral pO2 from baseline value. During ischemic stroke, induced by embolic clot in the left brain, a significant decline in the pO2 of the left cortex (ischemic core) was observed without any change in the contralateral sites. While the pO2 in the non-infarct regions returned to baseline at 24-h post-stroke, pO2 in the infarct core was consistently lower compared to the baseline and other regions of the brain. The results demonstrated that electron paramagnetic resonance oximetry with the implantable resonator can repeatedly and simultaneously report temporal changes in cerebral pO2 at multiple sites. This oximetry approach can be used to develop interventions to rescue hypoxic/ischemic tissue by modulating cerebral pO2 during hypoxic and stroke injury.

Purpose and introduction Thromboembolic material producing large vessel occlusion of the cerebral arteries varies substantially in composition and these differences affect the ability of both intravenous thrombolysis and mechanical thrombectomy to achieve rapid arterial recanalization. The binding of targeted magnetic nanoparticles may offer a means of noninvasively determining clot composition. We hypothesize that binding of targeted magnetic nanoparticles to thrombus is measurable and varies with clot composition. Materials and methods Thromboembolic material was extracted from 10 patients during emergent mechanical thrombectomy for large vessel occlusion in ICA, MCA, or basilar arteries. The nominal source of the thromboembolic material and time from onset to clot retrieval were recorded. Each sample was divided and sent both for standard histopathologic evaluation and for in vitro assessment by magnetic spectroscopy of nanoparticle Brownian rotation (MSB). The thromboembolic material was incubated in a solution of magnetic nanoparticles that had been coated with antibodies directed toward thrombin. Nanoparticle binding was measured using magnetic relaxometry. Results All clots bound measurable quantities of the thrombin-directed magnetic nanoparticles. 2/10 of the samples were composed of >90% fibrin material. These two samples demonstrated much higher than expected nanoparticle binding. The other samples had proportions of thrombus that ranged from 50 to 60%. Among these samples there was a significant correlation between nanoparticle weight and RBC content (R2 = 0.70, p Discussion Thrombin-directed nanoparticles bound thrombin-rich thromboembolic material roughly in proportion to the RBC content, as expected, confirming an affinity of these particles for this component of the clot. However, samples consisting almost exclusively of fibrin bound even higher levels of the nanoparticles suggesting the presence of an additional binding mechanism. Disclosures C. Eskey: None. W. Wells: None. D. Schartz: None. C. Jackson: None. J. Weaver: None.

Purpose Penetrating facial trauma is an uncommon injury, but patients who present with these dramatic situations require special consideration. We describe the case of a young man who had been shot with an arrow that deeply penetrated his midface as well as report the results of a literature review of penetrating midface injuries. The information gathered was used to create a diagnostic protocol for patients who sustain such injuries. Methods A PubMed search up to October 2019 using several key phrases was performed, and 623 unique articles were evaluated. Excluding firearm injuries to the midface, there were 57 unique cases that involved penetrating midface injuries. Clinical and imaging data were compiled and evaluated with descriptive statistical analysis. Results The average patient age was 27 years, with a male predilection. The most common reported etiology was accidental trauma (54%), and a knife was the most common weapon of injury (30%). The most common (32%) specific location of trauma was within the orbital region, including the canthus or the eyelid. In all cases where the patient had not died immediately, surgery was used to remove the penetrating object. We found that computed tomography was the most commonly obtained imaging study (39% of cases). Radiographs were the sole imaging in 28% of the cases, with angiography (16%) and magnetic resonance imaging (10%) used less frequently in management. In 28% of the cases, deep structures, such as the carotid artery, sphenoid sinus, or skull base, were involved in the injury. In 25% of the cases, there was injury to the central nervous system. Death occurred in 8.8% of the cases. Postoperative complications occurred in at least 21% of the cases. Statistical analysis also revealed a significant correlation between antibiotic use and full recovery. Penetration of the object posterior to the maxillary sinus was correlated with incomplete recovery or death. Conclusions Based on all case reports collected, a Dartmouth Penetrating Midface Protocol was developed to aid the practitioner who may happen to be responsible for these dramatic life-threatening injuries. The Dartmouth Penetrating Midface Protocol is based on the type of imaging available at the treating facility, the neurologic and hemodynamic stability of the patient, and the depth of penetration beyond the posterior wall of the maxillary sinus.

Intracranial endovascular interventions provide effective and minimally invasive treatment of a broad spectrum of diseases. This area of expertise has continued to gain both wider application and greater depth as new and better techniques are developed and as landmark clinical studies are performed to guide their use. Some of the greatest advances since the last American Heart Association scientific statement on this topic have been made in the treatment of ischemic stroke from large intracranial vessel occlusion, with more effective devices and large randomized clinical trials showing striking therapeutic benefit. The treatment of cerebral aneurysms has also seen substantial evolution, increasing the number of aneurysms that can be treated successfully with minimally invasive therapy. Endovascular therapies for such other diseases as arteriovenous malformations, dural arteriovenous fistulas, idiopathic intracranial hypertension, venous thrombosis, and neoplasms continue to improve. The purpose of the present document is to review current information on the efficacy and safety of procedures used for intracranial endovascular interventional treatment of cerebrovascular diseases and to summarize key aspects of best practice.

Over the past decade there has been a growing use of intracranial stents for the treatment of both ischemic and hemorrhagic cerebrovascular disease, including stents to assist in the remodeling of the neck of aneurysms as well as the use of flow diverting devices for aneurysm treatment. With this increase in stent usage has come a growing need for the neurointerventional (NI) community to understand the pharmacology of medications used for modifying platelet function, as well as the testing methodologies available. Platelet function testing in NI procedures remains controversial. While pre-procedural antiplatelet assays might lead to a reduced rate of thromboembolic complications, little evidence exists to support this as a standard of care practice. Despite the routine use of dual antiplatelet therapy (DAT) with aspirin and a P2Y12 receptor antagonist (such as clopidogrel, prasugrel, or ticagrelor) in most neuroembolization procedures necessitating intraluminal reconstruction devices, thromboembolic complications are still encountered.1–3 Moreover, DAT carries the risk of hemorrhagic complications, with intracerebral hemorrhage (ICH) being the most potentially devastating.4 ,5 Light transmission aggregometry (LTA) is the gold standard to test for platelet reactivity, but it is usually expensive and may not be easily obtainable at many centers. This has led to the development of point-of-care assays, such as the VerifyNow (Accumetrics, San Diego, California, USA), which correlates strongly with LTA and can reliably measure the degree of P2Y12 receptor inhibition.6–9 VerifyNow results are reported in P2Y12 reaction units (PRUs), with a lower PRU value corresponding to a higher level of P2Y12 receptor inhibition and, presumably, a lower probability of platelet aggregation, and a higher PRU value corresponding to a lower level of P2Y12 receptor inhibition and, hence, a higher chance of platelet activation and aggregation. While aspirin resistance is perhaps less common, clopidogrel resistance may be more challenging as …

Vertebroplasty and kyphoplasty are minimally invasive image-guided procedures that involve the injection of cement (typically polymethylmethacrylate (PMMA)) into a vertebral body. Kyphoplasty involves inflation of a balloon tamp to create a cavity within the vertebral body into which cement is subsequently injected. The majority of these vertebral augmentation procedures are performed to relieve back pain from osteoporotic or cancer-related vertebral compression fractures and to reinforce the vertebral body with neoplasm or vascular tumor. The primary goal of vertebroplasty and kyphoplasty is to reduce back pain and to improve patient's functional status, and the secondary goal is stabilization of a vertebra weakened by fracture or neoplasia. ### Osteoporotic vertebral fractures Osteoporosis is a common disease that causes significant morbidity and incurs a significant healthcare cost to the community. The major osteoporotic fractures involve the hip, vertebra, proximal humerus and distal forearm; the lifetime osteoporotic fracture risk at age 50 is approximately one in two women and one in five men.1 The lifetime incidence of symptomatic osteoporotic vertebral fractures in women at age 50 is estimated at 10–15%1; once a vertebral fracture occurs, there is a 20% risk of another vertebral fracture within 12 months.2 Most osteoporotic vertebral compression fractures are asymptomatic or result in minimal pain; only a third of vertebral fractures result in medical attention.3 Conservative medical therapy is therefore appropriate for the vast majority of vertebral compression fractures since most acute back pain symptoms are mild and subside over a period of 6–8 weeks as the fracture heals. The goals of conservative therapy are pain reduction (with analgesics and/or bed rest), improvement in functional status (with orthotic devices and physical therapy) and prevention of future fractures (with vitamin D, calcium supplementation and antiresorptive agents). However, conservative treatment for those with severe pain or limitation of function is not benign. It …

Purpose To analyze 2 factors that influence timing of radiosurgery after surgical resection of brain metastases: target volume dynamics and intracranial tumor progression in the interval between surgery and cavity stereotactic radiosurgery (SRS). Methods and Materials Three diagnostic magnetic resonance imaging (MRI) scans were retrospectively analyzed for 41 patients with a total of 43 resected brain metastases: preoperative MRI scan (MRI-1), MRI scan within 24 hours after surgery (MRI-2), and MRI scan for radiosurgery planning, which is generally performed ≤1 week before SRS (MRI-3). Tumors were contoured on MRI-1 scans, and resection cavities were contoured on MRI-2 and MRI-3 scans. Results The mean tumor volume before surgery was 14.23 cm 3 , and the mean cavity volume was 8.53 cm 3 immediately after surgery and 8.77 cm 3 before SRS. In the interval between surgery and SRS, 20 cavities (46.5%) were stable in size, defined as a change of ≤2 cm 3 ; 10 cavities (23.3%) collapsed by >2 cm 3 ; and 13 cavities (30.2%) increased by >2 cm 3 . The unexpected increase in cavity size was a result of local progression (2 cavities), accumulation of cyst-like fluid or blood (9 cavities), and nonspecific postsurgical changes (2 cavities). Finally, in the interval between surgery and SRS, 5 cavities showed definite local tumor progression, 4 patients had progression elsewhere in the brain, 1 patient had both local progression and progression elsewhere, and 33 patients had stable intracranial disease. Conclusions In the interval between surgical resection and delivery of SRS, surgical cavities are dynamic in size; however, most cavities do not collapse, and nearly one-third are larger at the time of SRS. These observations support obtaining imaging for radiosurgery planning as close to SRS delivery as possible and suggest that delaying SRS after surgery does not offer the benefit of cavity collapse in most patients. A prospective, multi-institutional trial will provide more guidance to the optimal timing of cavity SRS.

Current clinical practice standards are addressed for the invasive interventional management of post-hemorrhagic cerebral vasospasm (PHCV) in patients with aneurysmal subarachnoid hemorrhage. The conclusions, based on an assessment by the Standards Committee of the Society of Neurointerventional Surgery, included a critical review of the literature using guidelines for evidence based medicine proposed by the Stroke Council of the American Heart Association and the University of Oxford, Centre for Evidence Based Medicine. Specifically examined were the safety and efficacy of established invasive interventional therapies, including transluminal balloon angioplasty (TBA) and intra-arterial vasodilator infusion therapy (IAVT). The assessment shows that these invasive interventional therapies may be beneficial and may be considered for PHCV-that is, symptomatic with cerebral ischemia and refractory to maximal medical management. As outlined in this document, IAVT may be beneficial for the management of PHCV involving the proximal and/or distal intradural cerebral circulation. TBA may be beneficial for the management of PHCV that involves the proximal intradural cerebral circulation. The assessment shows that for the indications described above, TBA and IAVT are classified as Class IIb, Level B interventions according to the American Heart Association guidelines, and Level 4, Grade C interventions according to the University of Oxford Centre for Evidence Based Medicine guidelines.

These guidelines were developed by consensus of a multidisciplinary panel of specialists interested in the evaluation and treatment of patients with arteriovenous malformations (AVMs) of the CNS. The reporting criteria described will serve as a template for trial design and for clinical investigators who wish to report on endovascular therapy of cerebral AVMs. Direct comparison of various treatment paradigms is important to standardization of care, maximization of good treatment outcomes, assessment of new methods and technologies.

When patients present to the emergency room with sudden onset of focal neurologic symptoms or altered consciousness, hemorrhagic stroke is a major focus of emergency diagnostic evaluation. The entities that compose hemorrhagic stroke, intracerebral and subarachnoid hemorrhage, are readily diagnosed with advanced imaging. This article reviews current imaging options for the detection of acute hemorrhage, along with the expected imaging findings for each modality. Common and unusual causes and their distinguishing imaging features are discussed. Imaging strategies and recent work in specific imaging findings that may guide patient management in the future are also addressed.

STUDY DESIGN Retrospective case series. OBJECTIVE To determine the incidence of additional vertebral compression fractures diagnosed with repeat MRI immediately before vertebroplasty or kyphoplasty. SUMMARY OF BACKGROUND DATA Vertebral compression fractures, which occur frequently in the elderly, are more likely in patients with prior vertebral compression fracture. When patients are evaluated for vertebroplasty, it is important to identify all unhealed fractures for effective treatment planning. METHODS In a retrospective study, we reviewed the records of all patients (n = 194) treated with vertebroplasty or kyphoplasty over a 6-year period at our institution, and identified all patients who had undergone a repeat MRI within 7 days of vertebroplasty or kyphoplasty. These studies were obtained as part of a clinical protocol prescribing a repeat MRI for any patient whose MRI had been obtained more than 3 months before the evaluation, or who had a change in their pain between referral and evaluation. RESULTS Twenty patients met inclusion criteria for the immediate preprocedure MRI protocol. A total of 14 new fractures in 11 patients were discovered on the immediate preprocedure MRI. Of these 14, 6 had less than 15% loss of height, making them potentially occult on radiographs; 3 fractures developed in 2 patients who had no change in back pain. CONCLUSION In select candidates for vertebroplasty or kyphoplasty, a repeat preprocedure MRI obtained within 1 week can help ensure that all painful fractures are treated. There is demonstrable value in this protocol for patients with an imaging evaluation over 3 months old or who have had any change in symptoms since the initial imaging workup.

Object In 2002, “quick-brain” (QB) MR imaging (ultrafast spin echo T2-weighted imaging) was introduced as an alternative technique to CT scanning for assessing children with hydrocephalus. The authors have observed high patient and physician satisfaction with this technique at their institution, which has led to an increasing frequency of its use for nonhydrocephalic indications. The goal in this study was to characterize, quantitate, and assess the use of QB MR imaging for these additional indications. Methods Between February 2003 and December 2007, 1146 consecutive QB MR imaging studies were performed, and the findings were entered prospectively into a radiology database. All available clinical records were retrospectively reviewed to assign ≥ 1 of the following indications to each study: hydrocephalus, macrocephaly, Chiari malformation, intracranial cyst, screening prior to lumbar puncture, screening for congenital anomalies, trauma, and other. Changes in the distribution of indications over time and clinical experience for each indication were reviewed. Results The total number of QB imaging studies performed increased each year. The proportion of studies performed for nonhydrocephalic indications also increased (from 23 to 50%). The most common indication was screening for macrocephaly, and all other indications were nearly evenly distributed. Quick-brain MR imaging was used extensively for the initial evaluation and follow-up in patients with little need for additional studies. Its false-negative rate, however, remains unknown. Conclusions The role of QB MR imaging for nonhydrocephalic indications is expanding, and it appears promising for a number of screening and surveillance paradigms. “Quick-brain plus” protocols for specific indications may add sensitivity and are under development.

Osteoporotic vertebral compression fractures result in an enormous medical, social and economic burden to society. Here, we review osteoporotic vertebral compression fractures, focusing on both their diagnosis and the treatment options, particularly vertebral augmentation.

The primary event in the ischemic stroke is a rapid decline in the oxygen levels after the loss of blood flow in specific areas of the brain. Subsequent pathological processes results in a central core area of severely ischemic tissue surrounded by a region of moderate ischemic tissue (penumbra) with a preserved cellular metabolism. The outcome of an ischemic stroke depends on the size of the infarct core and the potential to salvage the cells in the penumbra, which is hypoperfused, and therefore, at risk of infarction but still viable. Such viable penumbral tissue can be rescued by quick interventions that can increase oxygen levels or slow metabolism in the ischemic area to minimize oxidative injury on reperfusion. Several strategies have been investigated to rescue ischemic tissue using experimental models, especially rodents, but largely failed in subsequent clinical trials. The rabbit model of ischemic stroke using embolic clot is a promising model for developing effective strategies. This model first led to the prediction of the clinical response of recombinant tissue-type plasminogen activator to restore blood flow in patients.1 The drug is currently recommended for administration within 3 hours for best outcomes and has also shown modest benefit when administered within 4.5 to 6 hours of clinical onset.2 The rabbit model of embolic clot is now considered as a pertinent model for translational research by the Stroke Therapy Academic Industry Roundtable recommendations.3 To rationally develop effectual therapies, it is important to understand the effect of ischemic stroke on oxygen levels (partial pressure of oxygen [pO2]) in the regions directly affected by the pathology, as well as contralateral regions of the rabbit brain. The potential changes in tissue po2 of contralateral regions may provide crucial information on adaptive response, if any, of the brain …

PURPOSE The treatment of painful compression fractures has been revolutionized by vertebroplasty and kyphoplasty, two recently developed techniques that continue to evolve. This article describes a new device for the performance of kyphoplasty that uses a polymer device rather than a balloon to create a void in the bone. MATERIALS AND METHODS In nine consecutive patients, kyphoplasty was performed at 12 vertebral levels with osteoporotic compression with use of the new SKy bone expander polymer device. RESULTS The device was successful in creating a void in the bone at all levels. The procedure was also effective in alleviating pain from compression fractures. There were no technical failures or complications. CONCLUSION The SKy bone expander polymer device is effective and safe for the performance of kyphoplasty to alleviate pain from vertebral compression fractures.

Object The piglet is an excellent model for the developing human brain, and has been used increasingly in various centers for studies of traumatic brain injury and other insults. Unlike rodent or primate models, however, there are few behavioral scales for the piglet, and the available ones are used to test general responsiveness rather than specific functional outcome. The differing behavioral repertoires of animals of different ages provide an additional challenge when age-dependent injury responses are compared. To overcome these experimental limitations of piglets in brain injury research, the authors developed a functional magnetic resonance (fMR) imaging paradigm that can be used to track recovery in the somatosensory cortex over time in anesthetized animals of different ages. Methods Fifteen fMR imaging studies in eight piglets were performed before and after scaled cortical impact injury to the primary somatosensory cortex subserving snout sensation. Specific anesthetic and imaging protocols enabled visualization of cortical activation, and comparison with somatosensory evoked potentials obtained before and after injury was obtained. A piglet brain template for group-level analysis of these data was constructed, similar to the fMR imaging techniques used in humans, to allow for group comparisons and longitudinal change analysis over time. Conclusions Loss of function in a specifically traumatized cortical region and its subsequent recovery over time can now be demonstrated visually by fMR imaging in the piglet. Besides its value in understanding intrinsic recovery mechanisms and plasticity at different ages, this functional outcome measure will enable the use of the piglet model in treatment trials specifically designed for the immature brain.

Purpose: To report orgasmic epilepsy as a manifestation of paraneoplastic limbic encephalitis in a patient with small cell lung cancer. Case report: A 57 years-old woman presented with 2 month history of daily spells that consisted of a sudden pleasure provoking feeling described ‘like an orgasm’ lasting for 30 s to 1 min. She was a heavy smoker and had noted recent weight loss. Bronchial biopsy, following the finding of a right lung mass, confirmed the diagnosis of small cell lung cancer (SCLC). Spells subsided after starting carbamazepine. The lung cancer was treated with chemotherapy and chest radiation therapy resulting in a complete radiologic response. Results: Brain magnetic resonance imaging (MRI) revealed left temporal lobe area of increased signal on T2 and FLAIR sequence. T1-weighted images after contrast administration demonstrated a circumscribed area of enhancement in the left anterior medial temporal lobe. Electroencephalogram (EEG) showed focal left mid-temporal sharp waves and intermittent slowing. Anti-Hu antibodies were detected in her serum supporting a diagnosis of paraneoplastic limbic encephalitis as the cause of her orgasmic epilepsy. The patient has been followed for 2 years after treatment without tumor recurrence or neurological deterioration. Conclusion: Orgasmic epilepsy is another mode of presentation of paraneoplastic limbic encephalitis leading to the diagnosis of an occult SCLC. EEG and MRI findings suggest that in this case the seizures originated from the left hemisphere. It is possible that early recognition and treatment of the SCLC will improve the prognosis of this neurologic entity.

Neurologic injuries, whether subtle or overt, are a major source of morbidity secondary to coronary artery bypass graft (CABG) surgery. A comprehensive review of research in the area of neurologic injury is provided. We conclude this article by providing insight regarding areas requiring further investigation in order to reduce sustainably the risk of these iatrogenic events among patient undergoing CABG surgery.

Purpose CT angiography (CTA) is rapidly becoming a popular tool for the evaluation of cerebrovascular diseases. Noninvasive diagnosis of vertebral artery pathology using CTA relies in part on diminished vertebral artery size or eccentric position relative to the transverse foramen. However, normal variation of the vertebral artery on CT has not been systematically described. Method Patients younger than 40 years who underwent CTA for reasons other than evaluation of vertebral artery disease were studied. Area measurements of the vertebral artery and the transverse foramen were performed by three radiologists. Variance component analysis was performed. Results There is marked variation in the size of the vertebral artery relative to the transverse foramen, with the vertebral artery occupying 8-85% of the foramen. In many patients, marked asymmetry in relative vertebral artery size and position was observed. This asymmetry would often vary markedly from level to level within the same patient. Conclusion Vertebral artery size and position in the transverse foramina vary markedly in normal young subjects. These normal variations must be considered when evaluating vertebral artery pathology on CT angiograms.

Soft tissue tumors of the neck are a heterogeneous group of neoplasms arising from adipose, muscular, and fibrous tissue. With the exception of lymphomas, they account for only a small fraction of neck masses. Nevertheless, accurate diagnosis is important since the behavior of these neoplasms differs markedly from each other and from other head and neck masses. Noninvasive imaging, usually with CT and MR imaging, plays an important role in diagnostic evaluation and treatment planning for these tumors. In some cases, imaging features may be suggestive of a single entity. In most cases, imaging is needed to assess the location and extent of the tumor prior to biopsy or excision. This article discusses imaging techniques used for such assessment, the imaging features that help to separate these neoplasms from other head and neck tumors, and the behavior and imaging features of each of the more common benign and malignant soft tissue tumors that occur in the neck.

SUMMARY: Bone wax used in neurosurgical procedures is a rare cause of complications after surgery. We present a patient who developed paraplegia following thoracic spine surgery. A subsequent MR imaging study demonstrated a signal void that resembled postoperative air but appeared to cause cord compression and proved after a second surgery to represent bone wax. Recognizing the MR imaging and CT characteristics of bone wax is important to prevent mistaking it for residual air in postoperative imaging.

Background Benchmarking of complications is necessary in the context of the developing path to accountable care. We attempted to create a predictive model of negative outcomes in patients undergoing cerebral aneurysm coiling (CACo). Methods We performed a retrospective cohort study involving patients who underwent CACo from 2005 to 2009 and who were registered in the Nationwide Inpatient Sample database. A model for outcome prediction based on individual patient characteristics was developed. Results Of the 10 607 patients undergoing CACo, 6056 presented with unruptured aneurysms (57.1%) and 4551 with subarachnoid hemorrhage (42.9%). The respective inpatient postoperative risks were 0.3%, 5.7%, 1.8%, 0.8%, 0.5%, 0.2%, 1.9%, and 0.1% for unruptured aneurysms, and 13.8%, 52.8%, 4.9%, 36.7%, 1%, 2.9%, 2.3%, and 0.8% for ruptured aneurysms for death, unfavorable discharge, stroke, treated hydrocephalus, cardiac complications, deep vein thrombosis, pulmonary embolism, and acute renal failure. Multivariate analysis identified risk factors independently associated with the above outcomes. A validated model for outcome prediction based on individual patient characteristics was developed. The accuracy of the model was estimated by the area under the receiver operating characteristic curve, and it was found to have good discrimination. Conclusions The presented model can aid in the prediction of the incidence of postoperative complications, and can be used as an adjunct in tailoring the treatment of cerebral aneurysms.

Many pathologies alter the mechanical properties of tissue. Magnetic resonance elastography (MRE) has been developed to noninvasively characterize these quantities in vivo. Typically, small vibrations are induced in the tissue of interest with an external mechanical actuator. The resulting displacements are measured with phase contrast sequences and are then used to estimate the underlying mechanical property distribution. Several MRE studies have quantified brain tissue properties. However, the cranium and meninges, especially the dura, are very effective at damping externally applied vibrations from penetrating deeply into the brain. Here, we report a method, termed 'intrinsic activation', that eliminates the requirement for external vibrations by measuring the motion generated by natural blood vessel pulsation. A retrospectively gated phase contrast MR angiography sequence was used to record the tissue velocity at eight phases of the cardiac cycle. The velocities were numerically integrated via the Fourier transform to produce the harmonic displacements at each position within the brain. The displacements were then reconstructed into images of the shear modulus based on both linear elastic and poroelastic models. The mechanical properties produced fall within the range of brain tissue estimates reported in the literature and, equally important, the technique yielded highly reproducible results. The mean shear modulus was 8.1 kPa for linear elastic reconstructions and 2.4 kPa for poroelastic reconstructions where fluid pressure carries a portion of the stress. Gross structures of the brain were visualized, particularly in the poroelastic reconstructions. Intra-subject variability was significantly less than the inter-subject variability in a study of six asymptomatic individuals. Further, larger changes in mechanical properties were observed in individuals when examined over time than when the MRE procedures were repeated on the same day. Cardiac pulsation, termed intrinsic activation, produces sufficient motion to allow mechanical properties to be recovered. The poroelastic model is more consistent with the measured data from brain at low frequencies than the linear elastic model. Intrinsic activation allows MRE to be performed without a device shaking the head so the patient notices no differences between it and the other sequences in an MR examination.

Spinal dural arteriovenous fistula (DAVF) is an uncommon condition that can be difficult to diagnose. This often results in misdiagnosis and treatment delay. Although conventional MRI plays an important role in the initial screening for the disease, the typical MRI findings may be absent. In this article, the authors present a series of 4 cases involving patients with angiographically proven spinal DAVFs who demonstrated cord T2 prolongation on conventional MRI but without abnormal subarachnoid flow voids or enhancement. These cases suggest that spinal DAVF cannot be excluded in symptomatic patients with cord edema based on conventional MRI findings alone. Dynamic Gd-enhanced MR angiography (MRA) was successful in demonstrating abnormal spinal vasculature in all 4 cases. This limited experience provides support for the role of spinal MRA in patients with abnormal cord signal and symptoms suggestive of DAVF even when typical MRI findings of a DAVF are absent.

These guidelines were developed by consensus of a multidisciplinary panel of specialists interested in the evaluation and treatment of patients with arteriovenous malformations (AVMs) of the CNS. The reporting criteria described will serve as a template for trial design and for clinical investigators who wish to report on endovascular therapy of cerebral AVMs. Direct comparison of various treatment paradigms is important to standardization of care, maximization of good treatment outcomes, assessment of new methods and technologies.

The role of glycolysis vs. respiration in tumor energy metabolism has been studied, to date, primarily in vitro by using single cells, multicellular spheroids, or tissue slices. With the advent of in vivo NMR spectroscopy, several investigators have shown that tumor energy status depends on its blood flow. Since manipulation of blood flow alters both oxygen and glucose delivery to a solid tumor, these studies have not been able to separate the relative contribution of oxygen vs. glucose in energy metabolism in vivo. In the present study, we have overcome this problem by combining two methods: the tissue-isolated R3230AC mammary adenocarcinoma perfused ex vivo and 31P NMR spectroscopy. The isolated tumor permits one to control the perfusion pressure as well as the metabolite concentrations in the perfusate. NMR spectroscopy permits one to measure the ratio of nucleoside triphosphate to inorganic phosphate (NTP/Pi) and pH. Our results show that (i) the NTP/Pi ratio ex vivo is similar to that observed in vivo prior to surgery, (ii) the NTP/Pi ratio is insensitive to flow changes at high flow rates but is proportional to flow rate at flows comparable to those found in vivo, (iii) the NTP/Pi ratio of these tumors is resistant to hypoxia and is not maintained when glucose is removed or replaced with glutamine, and (iv) although both O2 and glucose are consumed by these tumors, the effect of perfusate flow rate appears to be mediated largely through glucose delivery. The current approach not only provides information about the role of glycolysis vs. respiration in a rodent tumor but also is general and versatile enough to provide similar data in human tumors perfused ex vivo.