Extracranial-intracranial Bypass Research Articles

Emerging Endovascular Therapies for Symptomatic Intracranial Atherosclerotic Disease

Marc Fisher MD Section Editor Over the past 2 decades there has been an exponential growth in the scope of disease processes amenable to neuroendovascular treatment. The number and sophistication of the available devices and correspondingly the number of patients undergoing treatment has expanded accordingly. The development and implementation of these new procedures has in some cases outpaced our ability to carefully assess their merits. In comparison to peripheral and coronary vascular disease, neurovascular lesions are less common and far more heterogeneous, ranging from acquired cerebrovascular ischemic disease to hemorrhagic congenital arteriovenous malformations. Each individual disease process (eg, cerebral aneurysm) is composed of a myriad of lesions with different anatomical and pathophysiological characteristics. The natural history of these lesions and their subtypes are likewise poorly defined. For these reasons, personal bias, institutional custom, and anecdotal experience rather than scientific evidence have played a dominant role in guiding therapy. We must move toward collaborative multi-center efforts, prospective data collection and well designed randomized controlled trials to mature as a field over the coming decades. In some ways, symptomatic intracranial atherosclerotic disease (SxICAD) represents an optimal disease process with which to establish this progress toward evidenced based treatment. SxICAD is considerably less heterogeneous than other cerebrovascular disease processes and is arguably best suited as a paradigm for study. In the current article we have attempted to review the available evidence describing the natural history of medically treated SxICAD to determine those patients best suited for invasive treatment strategies. We will also discuss the available treatment modalities which may represent viable options to medical therapy. These data form the basis for the design of future prospective multicenter studies to evaluate the relative merits of interventional treatment. Any invasive treatment strategy for symptomatic intracranial atherosclerosis must satisfy two criteria to establish viability as a …

Major Ongoing Stroke Trials

Major Ongoing Stroke Trials

Large Field Trial for Lung Cancer Screening: Putting the Wrong Cart before the Horse?—Commentary

HomeRadiologyVol. 243, No. 2 PreviousNext Reviews and CommentaryEditorialsLarge Field Trial for Lung Cancer Screening: Putting the Wrong Cart before the Horse?—CommentaryDavid GurDavid GurAuthor Affiliations1From the Department of Radiology, University of Pittsburgh, Imaging Research, Suite 4200, 300 Halket St, Pittsburgh, PA 15213. Received July 19, 2006; final version accepted July 24. Address correspondence to the author (e-mail: [email protected]).David GurPublished Online:May 1 2007https://doi.org/10.1148/radiol.2431061252MoreSectionsFull textPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In References1 Black WC, Aberle DR, Berg CD. Large field trial for lung cancer screening: putting the wrong cart before the horse? Radiology 2007; 243(1): 314–316. Link, Google Scholar2 Gur D. Lung cancer screening: radiology's opportunity here and now. Radiology 2006; 238(2): 395–397. Link, Google Scholar3 Pisano ED, Gatsonis CA, Yaffe MJ, et al. American College of Radiology Imaging Network digital mammographic imaging screening trial: objectives and methodology. Radiology 2005; 236(2): 404–412. Link, Google Scholar4 Failure of extracranial-intracranial arterial bypass to reduce the risk of ischemic stroke: results of an international randomized trial. The EC/IC Bypass Study Group. N Engl J Med 1985; 313(19): 1191–1200. Crossref, Medline, Google Scholar5 Planning for progress: office of science planning and assessment (OSPA)—report of the Lung Cancer Progress Review Group. National Cancer Institute Web site. http://planning.cancer.gov/pdfprgreports/2001lung.pdf. Accessed July 7, 2006. Google ScholarArticle HistoryPublished in print: 2007 FiguresReferencesRelatedDetailsRecommended Articles Low-Dose CT Screening for Lung Cancer: Evidence from 2 Decades of StudyRadiology: Imaging Cancer2020Volume: 2Issue: 2Barriers to Lung Cancer Screening Engagement from the Patient and Provider PerspectiveRadiology2019Volume: 290Issue: 2pp. 278-287Mediastinal Lymphadenopathy in the National Lung Screening Trial (NLST) Is Associated with Interval Lung CancerRadiology2021Volume: 302Issue: 3pp. 684-692The Vancouver Lung Cancer Risk Prediction Model: Assessment by Using a Subset of the National Lung Screening Trial CohortRadiology2016Volume: 283Issue: 1pp. 264-272Radiologic Features of Small Pulmonary Nodules and Lung Cancer Risk in the National Lung Screening Trial: A Nested Case-Control StudyRadiology2017Volume: 286Issue: 1pp. 298-306See More RSNA Education Exhibits Management of Solitary Pulmonary Nodules: Pushing the Limits Beyond the GuidelinesDigital Posters2019Shared Decision Making: A Primer for the Busy RadiologistDigital Posters2018Introduction to Artificial Intelligence and Big Data Research in Chest RadiologyDigital Posters2019 RSNA Case Collection Diffuse idiopathic pulmonary neuroendocrine cell hyperplasiaRSNA Case Collection2020Lung Carcinoma Metastatic to the BreastRSNA Case Collection2020Locally Advanced Breast CancerRSNA Case Collection2021 Vol. 243, No. 2 Metrics Altmetric Score PDF download

INTRAOPERATIVE APPLICATION OF THERMOGRAPHY IN EXTRACRANIAL-INTRACRANIAL BYPASS SURGERY

The extracranial-intracranial bypass may have the potential to improve hemodynamic cerebral ischemia caused by occlusive diseases of the main cerebral arteries. Intraoperative confirmation of effective distribution of blood flow via the donor arteries to the involved region will assure a successful bypass surgery. Infrared thermography was used to measure the temperature of the cortical surface at the operative field. Regional cerebral blood flow (rCBF) was measured with a laser Doppler flow meter. Changes in the cortical surface temperature before and after temporary occlusion of the bypass were compared with changes in rCBF values in the corresponding sites. Thermographic examination demonstrated a heterogeneous increase of cortical surface temperature caused by the blood flow via the extracranial-intracranial bypass and was closely related to rCBF changes. Thermography is useful not only to demonstrate the distribution of blood flow through the extracranial-intracranial bypass but also to quantitatively evaluate the rCBF changes in the operative field.

Complications of resection of malignant tumours of the skull base: outcome and solution

The results of surgical resection of malignant tumours located at the skull base have improved significantly over the years. There are however still some complications associated with these procedures. For central skull base lesions, the anterolateral approach exposes the region adequately for an oncological resection to be carried out. The development of palatal fistula in irradiated patient has been a nuisance. With modification of the palatal incision, this problem is now eliminated. For the management of osteoradronecrosis of the skull base, an uncommon late complication, a microvascular free muscle flap is required. For malignant pathologies located at the anterior skull base, a combined craniofacial resection is the treatment of choice. Our experience as well as those reported in the literature showed that when the skull base defect was small, the pericranial and the galeofrontalis flap were adequate for reconstruction. For larger defects, a microvascular free flap would be used. When the internal carotid artery is included in the resection, an extracranial-intracranial arterial bypass should be created before the resection of tumour. The most serious complication is the development of cerebral spinal fluid leakage. Conservative treatment is applicable for small leakage while for large leakage; the exact location of the leak must be identified before the defect can be closed successfully.

Evaluation of extracranial–intracranial bypass using quantitative magnetic resonance angiography

To date, angiography has been the primary modality for assessing graft patency following extracranial-intracranial bypass. The utility of a noninvasive and quantitative method of assessing bypass function postoperatively was evaluated using quantitative magnetic resonance (MR) angiography. One hundred one cases of bypass surgery performed over a 5.5-year period at a single institution were reviewed. In 62 cases, both angiographic and quantitative MR angiographic data were available. Intraoperative flow measurements were available in 13 cases in which quantitative MR angiography was performed during the early postoperative period (within 48 hours after surgery). There was excellent correlation between quantitative MR angiographic flow and angiographic findings over the mean 10 months of imaging follow up. Occluded bypasses were consistently absent on quantitative MR angiograms (four cases). The flow rates were significantly lower in those bypasses that became stenotic or reduced in diameter as demonstrated by follow-up angiography (nine cases) than in those bypasses that remained fully patent (mean +/- standard error of the mean, 37 +/- 13 ml/minute compared with 105 +/- 7 ml/minute, p = 0.001). Flows were appreciably lower in poorly functioning bypasses for both vein and in situ arterial grafts. All angiographically poor bypasses (nine cases) were identifiable by absolute flows of less than 20 ml/minute or a reduction in flow greater than 30% within 3 months. Good correlation was seen between intraoperative flow measurements and early postoperative quantitative MR angiographic flow measurements (13 cases, Pearson correlation coefficient = 0.70, p = 0.02). Bypass grafts can be assessed in a noninvasive fashion by using quantitative MR angiography. This imaging modality provides not only information regarding patency as shown by conventional angiography, but also a quantitative assessment of bypass function. In this study, a low or rapidly decreasing flow was indicative of a shrunken or stenotic graft. Quantitative MR angiography may provide an alternative to standard angiography for serial follow up of bypass grafts.

SELF-CLOSING U-CLIPS FOR INTRACRANIAL MICROANASTOMOSES IN HIGH-FLOW ARTERIAL BYPASS

Self-closing nitinol U-clips (Medtronic, Inc., Minneapolis, MN) have been used to create vascular microanastomoses by vascular surgeons. This device eliminates the need for suture management and knot tying. Therefore, a high-quality interrupted microvascular anastomosis can be obtained in a shorter period of time. This is the first report of a U-clip intracranial arterial microanastomosis for a high-flow extracranial-intracranial bypass using a radial artery graft. A 24-year-old woman with a history of chronic headache was admitted to the National Neurological Institute Carlo Besta after a brain computed tomographic scan revealed a giant serpentine aneurysm of her right middle cerebral artery. Magnetic resonance angiography and four-vessel angiography confirmed the diagnosis and ruled out other lesions. A radial artery graft was used to create a high-flow bypass between the external carotid artery and the postaneurysmal M2 segment of the right middle cerebral artery. Nitinol self-closing U-clips were used for the interrupted intracranial microanastomosis. After intraoperative near-infrared indocyanine green video angiography confirmed the bypass patency, the aneurysm could be trapped. The postoperative course was uneventful. The patient was discharged on the seventh postoperative day and was neurologically intact. Postoperative angiography documented the successful exclusion of the aneurysm and the presence of revascularization of the distal branches of the right middle cerebral artery through the bypass. This case demonstrates the efficacy of U-clips for intracranial microanastomoses.

Rapid Revascularization After Therapeutic Parent Artery Occlusion for a Large Intracavernous Carotid Artery Aneurysm -Case Report-

A 21-year-old woman presented with an unruptured large intracavernous aneurysm, which was spontaneously revascularized via unusual collateral pathways a short time after extracranial-intracranial bypass and surgical ligation of the proximal internal carotid artery. The patient had been treated for a large basilar trunk aneurysm with intraaneurysmal embolization using Guglielmi detachable coils, and an intracavernous carotid artery aneurysm treated conservatively. Two years later, the patient presented with right abducens nerve palsy, and was referred to our hospital. She had small nevi in the right forehead and eyelid. Cerebral angiography revealed enlargement of the intracavernous aneurysm. Superficial temporal artery-middle cerebral artery bypass followed by surgical carotid artery ligation were performed, and good patency of bypass and disappearance of the aneurysm were confirmed by intraoperative angiography. However, follow-up magnetic resonance angiography and cerebral angiography on the 20th postoperative day revealed revascularization of the internal carotid artery and the intracavernous carotid artery aneurysm via unusual collateral pathways. Subsequently, the recurrent aneurysm and the recanalized internal carotid artery were occluded by endovascular procedures. Histological examination of the nevus showed lack of properly organized vascular structures, and the diagnosis was angiodysplasia. The early development of unusual collateral pathway, and aneurysm formation at a young age might be related to the angiodysplasia. Revascularization is possible within a short time even in cases of intracavernous carotid artery aneurysm successfully treated with surgical ligation of the parent artery.

2. 臨床脳虚血の脳循環代謝と血行再建術の適応(PS2-3 頭蓋内血行再建のすべて, 第27回 日本脳神経外科コングレス総会)

2. 臨床脳虚血の脳循環代謝と血行再建術の適応(PS2-3 頭蓋内血行再建のすべて, 第27回 日本脳神経外科コングレス総会)

Augmentation of the Patency of an Extracranial-Intracranial Bypass Accompanied by the Occlusion of an Intracranial Stenotic Lesion

Augmentation of the Patency of an Extracranial-Intracranial Bypass Accompanied by the Occlusion of an Intracranial Stenotic Lesion

8. 脳主幹動脈閉塞性病変慢性期に対するバイパス術後過灌流症候群(PS2-3 頭蓋内血行再建のすべて, 第27回 日本脳神経外科コングレス総会)

8. 脳主幹動脈閉塞性病変慢性期に対するバイパス術後過灌流症候群(PS2-3 頭蓋内血行再建のすべて, 第27回 日本脳神経外科コングレス総会)

5. 後頭蓋窩血行再建の基本手技と pitfall(PS2-3 頭蓋内血行再建のすべて, 第27回 日本脳神経外科コングレス総会)

5. 後頭蓋窩血行再建の基本手技と pitfall(PS2-3 頭蓋内血行再建のすべて, 第27回 日本脳神経外科コングレス総会)

7. もやもや病における脳血行再建の特殊性(PS2-3 頭蓋内血行再建のすべて, 第27回 日本脳神経外科コングレス総会)

7. もやもや病における脳血行再建の特殊性(PS2-3 頭蓋内血行再建のすべて, 第27回 日本脳神経外科コングレス総会)

Spontaneous Recanalization of Occluded Standard Extracranial-Intracranial Arterial Bypass

Background: In the event of early failure of standard extracranial-intracranial arterial bypass, elective but prompt revision surgery is generally attempted under the assumption that early occlusion is permanent. However, little is known about the occurrence of spontaneous revascularization. Objective: To estimate the frequency and time course of spontaneous recanalization in primary extracranial-intracranial arterial bypass occlusion and re-evaluate diagnostic and therapeutic options facing spontaneous development. Methods and Results: In a retrospective analysis 176 patients with standard superficial temporal artery/middle cerebral artery bypass were included. Twenty-three patients had primary bypass occlusion. In 7 cases spontaneous recanalization was observed. Follow-up of these cases is presented. Conclusions: Early bypass occlusion has a high incidence of spontaneous recanalization within the first year. In stable patients the first choice may be noninvasive follow-up and postponing revision operation.

Long-term Clinical and Angiographic Follow-up of Unclippable Wrapped Inracranial Aneurysms

In Reply: We thank De Freitas and Choudhari et al. for their critical evaluation of our article (1). They have appropriately highlighted the salient weaknesses of our study. We welcome this opportunity to respond to their concerns and, in turn, to reiterate our philosophy on the use of wrapping techniques. The primary surgical treatment of intracranial aneurysms is clip ligation, and the superiority of clipping over wrapping is, in most cases, indisputable. During the past 10 years, we have clipped approximately 2300 aneurysms. Only 74 (3.2%) were wrapped as the primary treatment modality. The small subset that should be considered for wrapping includes fusiform and dissecting aneurysms, small blister aneurysms, and aneurysms with associated atheromatous disease or heavy calcification. For each of these subtypes, primary clip ligation risks compromise of the parent vessel and lumen of branch vessels. In such cases, wrapping should be considered as a viable alternative. We strongly caution against the use of wrapping techniques to treat ruptured aneurysms, and we regret not emphasizing this point more strongly in our article. Our own experience, along with the existing literature, indicates that rerupture rates are high in these patients. For patients with unclippable ruptured aneurysms (i.e., dissecting supraclinoid internal carotid artery aneurysms), we recommend extracranial-intracranial bypass with parent vessel sacrifice or clip-wrapping followed soon thereafter by intraluminal reinforcement with Neuroform stent (Boston Scientific/Target, Fremont, CA) stenting. The evidence is compelling that wrapping ruptured aneurysms as a solitary treatment is not a viable option. The weaknesses of our study pertaining to patients lost to follow-up and the length of follow-up were acknowledged repeatedly in the article. These weaknesses should not be diminished. However, we presented the single largest series of wrapped intracranial aneurysms reported to date. Although these data are imperfect, we are confident that continued longitudinal examination of this cohort of patients will lead to a better understanding of the safety and efficacy of wrapping techniques. Vivek Deshmukh Washington, D.C. Robert F. Spetzler Phoenix, Arizona

Extracranial-intracranial bypass for the treatment of cavernous sinus aneurysms

The optimal management of symptomatic cavernous sinus aneurysms remains controversial. Carotid occlusion is a simple procedure, but carries an ongoing risk of early and late stroke. Cerebral revascularisation is technically demanding and carries a risk of morbidity and mortality of around 10%. Eight patients treated with an extracranial-intracranial vascular bypass graft over a period of 44 months for symptomatic cavernous sinus aneurysms are reviewed. At a mean follow-up of 20 months, seven patients (87.5%) had an excellent outcome (Glasgow Outcome Score 5) while one patient suffered a perioperative stroke. In only one case, where the radial artery had been used, the graft became occluded. The results of this series seem to indicate that cerebral revascularisation is an effective treatment for patients with symptomatic cavernous sinus aneurysms.

Changes in Brain Volume 2 Years after Extracranial-Intracranial Bypass Surgery: A Preliminary Subanalysis of the Japanese EC-IC Trial

Background and Methods: We studied changes in brain volume on magnetic resonance imaging in 10 patients with and without extracranial-intracranial (EC-IC) bypass surgery who met the inclusion criteria for the Japanese EC-IC Bypass Trial, a multicenter, randomized, prospective study of patients with hemodynamic brain ischemia due to cerebral artery occlusive disease. We also examined the association of cerebral hemodynamics on single-photon emission computed tomography with the changes in brain volume. Results: The affected/unaffected ratio of the percent brain volume declined in patients without EC-IC bypass surgery (p < 0.02, n = 4), and the affected/unaffected percent regional cerebral blood flow ratio increased in patients with the surgery (p < 0.03, n = 6). Acetazolamide reactivity increased in the affected hemisphere of patients with surgery (p < 0.01). Two-year increase (decrease) in acetazolamide reactivity of the affected hemisphere showed a significant positive correlation with 2-year changes in the affected/unaffected percent brain volume ratio (R² = 0.737, p = 0.0007). Conclusions: Change in acetazolamide reactivity might be a good predictor for brain atrophy in cerebral artery occlusive disease.

Long term evaluation of brain perfusion with magnetic resonance in high flow extracranial-intracranial saphenous graft bypass

Assessment was made of the cerebral vascular haemodynamic parameters in patients with a high-flow extra-intracranial (EC-IC) bypass performed for therapeutic occlusion of the internal carotid artery (ICA). Sixteen patients with ICA occlusion and EC-IC bypass (time interval from surgery 1-6 years) underwent MRI. Perfusion-weighted magnetic resonance imaging (PW-MRI) sequences were performed without the use of an arterial input function. The relative cerebral blood volume (rCBV), mean transit time (MTT) and relative cerebral blood flow (rCBF) were evaluated in all patients at the level of the basal ganglia, centrum semiovale and cortex in both hemispheres. Statistically significant differences (P<0.005) were observed in the haemodynamic parameters, indicating increased rCBV in the basal ganglia and decreased rCBF and rCBV in the cortex of the hemisphere supplied by the graft with respect to the contralateral. Patients with occlusion of the ICA and high flow EC-IC bypass do have altered vascular haemodynamic status between the hemispheres. In particular, rCBF is impaired in the surgical hemisphere at the level of the cortex. These patients should be followed-up to rule out chronic ischemia.

Intraoperative monitoring of cerebral blood oxygenation and hemodynamics during extracranial-intracranial bypass surgery by a newly developed visible light spectroscopy system

Background Cerebrovascular reconstruction procedures run the risk of changing the balance between oxygen supply and consumption during surgery. We assessed the value of visual light spectroscopy for detecting changes in cerebral blood oxygenation (CBO) during superficial temporal artery–middle cerebral artery (STA-MCA) anastomosis. Methods We developed a VLS monitoring system which permits continuous monitoring of CBO changes during surgery. Using the VLS, we evaluated the CBO changes in the MCA territory on the lesion side in 18 patients who underwent STA-MCA anastomosis. Results Temporary occlusion of the MCA (M4 portion) did not change the CBO in 17 patients. However, in the patient with dissecting aneurysm, it caused decreases of oxyhemoglobin and cortical oxygen saturation (CoS o 2) associated with an increase of deoxyhemoglobin, although these CBO changes were normalized by STA blood flow. In 5 patients, STA blood flow increased the oxyhemoglobin and CoS o 2 and decreased the deoxyhemoglobin, indicating that cortical blood flow (CoBF) was increased. The CoS o 2 before anastomosis was significantly low in the patients who showed an increase of CoS o 2 by STA blood flow (63.0% ± 2.5%) as compared with those who did not (72.0 ± 6.1%, P = .024). Conclusion Temporary occlusion of a cortical artery during bypass surgery did not affect the CBO in patients who had chronic cerebral ischemia, but caused acute ischemia in the patient who did not. STA blood flow increased the CoBF during surgery more frequently in patients who showed a low perfusion pressure. The VLS monitoring system is considered useful for evaluating bypass function and facilitates safe and accurate bypass surgery.

Major Ongoing Stroke Trials

Major Ongoing Stroke Trials