Kristine A Blackham

MDCT Angiography of the Spinal Vasculature and the Artery of Adamkiewicz

OBJECTIVE The purpose of our study was to prospectively assess 40-MDCT technology in combination with adapted brain reconstruction algorithms to visualize the spinal vasculature, in particular the artery of Adamkiewicz and its anatomic variants. SUBJECTS AND METHODS One hundred patients underwent contrast-enhanced MDCT of the thoracolumbar junction with collimation of 40 x 0.625 mm. The adapted brain algorithm reconstructed the spinal canal with a field of view of 90 mm at 0.6-mm slice thickness. Curved multiplanar reformations identified the artery of Adamkiewicz as a continuous vascular tract extending from the aortic orifices of the intercostal or lumbar arteries via the anterior radiculomedullary artery to the anterior spinal artery. Segment of origin and length were noted. Diameter and contrast-to-noise ratio (CNR) were evaluated along the posterior branch, the radiculomedullary artery, the artery of Adamkiewicz, and the anterior spinal artery. Univariate general linear model analysis with Bonferroni post hoc corrections evaluated whether laterality, segment of origin, and length of the artery of Adamkiewicz showed a sex-specific propensity. Multivariate general linear model analysis assessed whether spinal vascular diameters and intraluminal CNR showed correlations with sex, laterality, and segment of origin. Finally, the luminal diameters of the feeding posterior branches were statistically compared with those of the ipsilateral and contralateral adjacent posterior branches. RESULTS Successful depiction of the artery of Adamkiewicz was achieved in all patients; longitudinally the artery measured 40.1 +/- 13.51 mm. In 63% of patients it originated from the left side of the body, and in 74% it originated from the level of the 10th-12th thoracic vertebrae. Duplications were found in 5% of patients. Segmental distribution, laterality, and length did not show significant sex-specific differences (p > 0.05). The vascular diameter and luminal contrast did not show significant differences caused by sex, laterality, or segment of origin (p > 0.05). The diameter of the posterior branches (2.8 +/- 0.71 mm) arising in the segments of origin showed a significantly wider lumen than any of the other posterior branches (contralateral, 1.9 +/- 0.32 mm; upper ipsilateral, 2.0 +/- 0.47 mm; lower ipsilateral, 1.9 +/- 0.39 mm) (p < 0.0001). CONCLUSION Contrast-enhanced 40-MDCT technology, in combination with an adapted brain reconstruction algorithm, can depict the artery of Adamkiewicz and its anatomic variants.

Society for Neuroscience in Anesthesiology and Critical Care Expert Consensus Statement: Anesthetic Management of Endovascular Treatment for Acute Ischemic Stroke* Endorsed by the Society of NeuroInterventional Surgery and the Neurocritical Care Society

Literature on the anesthetic management of endovascular treatment of acute ischemic stroke (AIS) is limited. Anesthetic management during these procedures is still mostly dependent on individual or institutional preferences. Thus, the Society of Neuroscience in Anesthesiology and Critical Care (SNACC) created a task force to provide expert consensus recommendations on anesthetic management of endovascular treatment of AIS. The task force conducted a systematic literature review (up to August 2012). Because of the limited number of research articles relating to this subject, the task force solicited opinions from experts in this area. The task force created a draft consensus statement based on the available data. Classes of recommendations and levels of evidence were assigned to articles specifically addressing anesthetic management during endovascular treatment of stroke using the standard American Heart Association evidence rating scheme. The draft consensus statement was reviewed by the Task Force, SNACC Executive Committee and representatives of Society of NeuroInterventional Surgery (SNIS) and Neurocritical Care Society (NCS) reaching consensus on the final document. For this consensus statement the anesthetic management of endovascular treatment of AIS was subdivided into 12 topics. Each topic includes a summary of available data followed by recommendations. This consensus statement is intended for use by individuals involved in the care of patients with acute ischemic stroke, such as anesthesiologists, interventional neuroradiologists, neurologists, neurointensivists, and neurosurgeons.

Endovascular therapy of acute ischemic stroke: Report of the Standards of Practice Committee of the Society of NeuroInterventional Surgery

Objective To summarize and classify the evidence for the use of endovascular techniques in the treatment of patients with acute ischemic stroke. Methods Recommendations previously published by the American Heart Association (AHA) (Guidelines for the early management of adults with ischemic stroke (Circulation 2007) and Scientific statement indications for the performance of intracranial endovascular neurointerventional procedures (Circulation 2009)) were vetted and used as a foundation for the current process. Building on this foundation, a critical review of the literature was performed to evaluate evidence supporting the endovascular treatment of acute ischemic stroke. The assessment was based on guidelines for evidence based medicine proposed by the Stroke Council of the AHA and the University of Oxford, Centre for Evidence Based Medicine (CEBM). Procedural safety, technical efficacy and impact on patient outcomes were specifically examined.

Applications of Time-Resolved MR Angiography

OBJECTIVE The purpose of this essay is to describe the basic principles behind contrast-enhanced time-resolved MR angiography (MRA) performed with the time-resolved imaging with stochastic trajectories technique and to show examples of the versatile applications of this technique in the evaluation of pathologic conditions throughout the body. CONCLUSION Time-resolved MR angiography is a versatile technique for vascular imaging throughout the body. It can be used to answer a variety of clinical questions; to acquire diagnostically useful information, even about complicated vascular lesions; and to overcome many of the limitations of bolus-chase contrast-enhanced MR angiography. The technique is particularly useful when the arterial arrival time is uncertain, the patient is freely breathing, or contrast dynamics are critical to a diagnosis.

Invasive interventional management of post-hemorrhagic cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage

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.

Evaluation of Image Quality of a 32-Channel versus a 12-Channel Head Coil at 1.5T for MR Imaging of the Brain

How much better is a 32-channel head coil at 1.5T when compared with a 12-channel coil? Does the higher spatial resolution and signal-to-noise ratio affect clinical interpretations? Here, 21 patients were consecutively imaged with both coils and the results in axial T2, T1, fluid-attenuated inversion recovery, and diffusion-weighted imaging sequences were assessed. Most of the improvement was seen in the FLAIR, DWI, and T2 sequences and to a lesser extent on T1 images. Artifacts were similar with both coils. Conclusion: Improvements in SNR and spatial resolution attributed to image acquisition with a 32-channel head coil are paralleled by perceived improvements in image quality. BACKGROUND AND PURPOSE: Multichannel phased-array head coils are undergoing exponential escalation of coil element numbers. While previous technical studies have found gains in SNR and spatial resolution with the addition of element coils, it remains to be determined how these gains affect clinical reading. The purpose of this clinical study was to determine if the SNR and spatial resolution characteristics of a 32-channel head coil result in improvements in perceived image quality and lesion evaluation. MATERIALS AND METHODS: Twenty-one patients underwent MR imaging of the brain at 1.5T sequentially with both a 12-channel and a 32-channel receive-only phased-array head coil. Axial T2WIs, T1WIs, FLAIR images, and DWIs were acquired. Anonymized images were compared side-by-side and by sequence for image quality, lesion evaluation, and artifacts by 3 neuroradiologists. Results of the comparison were analyzed for the preference for a specific head coil. RESULTS: FLAIR and DWI images acquired with the 32-channel coil showed significant improvement in image quality in several parameters. T2WIs also improved significantly with acquisition by the 32-channel coil, while T1WIs improved in a limited number of parameters. While lesion evaluation also improved with acquisition of images by the 32-channel coil, there was no apparent improvement in diagnostic quality. There was no difference in artifacts between the 2 coils. CONCLUSIONS: Improvements in SNR and spatial resolution attributed to image acquisition with a 32-channel head coil are paralleled by perceived improvements in image quality.

Standard of practice: endovascular treatment of intracranial atherosclerosis.

Background Symptomatic intracranial atherosclerotic disease (ICAD) worldwide represents one of the most prevalent causes of stroke. When severe, studies show that it has a very high risk for recurrent stroke, highlighting the need for effective preventative strategies. The mainstay of treatment has been medical therapy and is of critical importance in all patients with this disease. Endovascular therapy is also a possible therapeutic option but much remains to be defined in terms of best techniques and patient selection. This guideline will serve as recommendations for diagnosis and endovascular treatment of patients with ICAD. Methods A literature review was performed to extract published literature regarding ICAD, published from 2000 to 2011. Evidence was evaluated and classified according to American Heart Association (AHA)/American Stroke Association standard. Recommendations are made based on available evidence assessed by the Standards Committee of the Society of NeuroInterventional Surgery. The assessment was based on guidelines for evidence based medicine proposed by the American Academy of Neurology (AAN), the Stroke Council of the AHA and the University of Oxford, Centre for Evidence Based Medicine (CEBM). Results 59 publications were identified. The SAMMPRIS study is the only prospective, randomized, controlled trial available and is given an AHA level B designation, AAN class II and CEBM level 1b. The Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial arteries (SSYLVIA) trial was a prospective, non-randomized study with the outcome assessment made by a non-operator study neurologist, allowing an AHA level B, AAN class III and CEBM level 2. The remaining studies were uncontrolled or did not have objective outcome measurement, and are thus classified as AHA level C, AAN class IV and CEBM level 4. Conclusion Medical management with combination aspirin and clopidogrel for 3 months and aggressive risk factor modification is the firstline therapy for patients with symptomatic ICAD. Endovascular angioplasty with or without stenting is a possible therapeutic option for selected patients with symptomatic ICAD. Further studies are necessary to define appropriate patient selection and the best therapeutic approach for various subsets of patients.

Analysis of short-term total hospital costs and current primary cost drivers of coiling versus clipping for unruptured intracranial aneurysms

Background No randomized controlled trial has successfully compared outcomes between endovascular coiling and microsurgical clipping for unruptured intracranial aneurysms (UIAs). Objective To perform a cost comparison between index hospitalizations of patients with UIAs treated with coil embolization or surgical clipping to identify the current primary drivers of costs of either management approach. Methods We obtained index hospitalization costs for 125 cases of UIAs treated with coiling or clipping from 2010 to 2012 at our institution. Comparisons were stratified based on patient age, gender, aneurysm size, and aneurysm location. Using linear regressions, we identified clinical parameters that drive total hospital costs. Results 69 cases were treated with clipping and 56 cases were treated with coiling. Morbidity and length of stay for patients treated with clipping was higher. Total hospital costs and variable direct costs for clipping were significantly lower than for coiling (p=0.003, p<0.001, respectively). Fixed direct costs and fixed indirect costs for clipping were higher than for coiling (p<0.001, p<0.001, respectively). Variable direct costs comprised 50.5% and 68.6% of total hospital costs for clipping and coiling, respectively (p<0.001). Length of stay, aneurysm size, and patient age drove total hospital costs for clipping. Length of stay was a weak driver of total hospital costs for coiling. Conclusions Total index hospitalization costs for clipping are lower than for coiling. Costs of clipping and coiling are driven by different clinical variables. The cost of coils and devices is the predominant contributor to the higher total costs of coiling.

Comparison of brain MR images at 1.5T using BLADE and rectilinear techniques for patients who move during data acquisition

BACKGROUND AND PURPOSE: MR imaging of moving patients can be challenging and motion correction techniques have been proposed though some have associated new artifacts. The objective of this study was to semiquantitatively compare brain MR images of moving patients obtained at 1.5T by using partially radial and rectilinear acquisition techniques. MATERIALS AND METHODS: FLAIR, T2-, T1-, and contrast-enhanced T1-weighted image sets of 25 patients (14–94 years) obtained by using BLADE (like PROPELLER, a partially radial acquisition) and rectilinear techniques in the same imaging session were compared by 2 neuroradiologists in terms of extent of the motion artifact, image quality, and lesion visibility. ICC between opinions of the evaluators was calculated. RESULTS: Of the total of 70 image sets, the motion artifact was small in the partially radial images in 43 and in the rectilinear images in 13, and the opinions of the evaluators were discordant in the remaining 14 sets (ICC = 0.63, P < .05). The quality of partially radial images was higher for 36 sets versus 9 rectilinear sets, with disagreement between the 2 evaluators in the remaining 25 (ICC = 0.15, P < .05). Pathologic lesions were better characterized on 37 sets of partially radial images versus 13 sets of rectilinear images, and opinions of the evaluators differed in 20 sets (ICC = 0.90, P < .05). The neuroradiologists deemed 4 sets of rectilinear images nondiagnostic compared with only 1 set of radial images. CONCLUSIONS: The data demonstrate that our application of BLADE sequences reduces the extent of motion artifacts in brain images of moving patients, improving image quality and lesion characterization.

Society of NeuroInterventional Surgery Standards of Practice: general considerations

This is the first in a set of documents intended to standardize techniques, procedures, and practices in the field of endovascular surgical neuroradiology. Standards are meant to define core practices for peer review, comparison, and improvement. Standards and guidelines also form the basic dialogue, reporting, and recommendations for ongoing practices and future development.