Biplane Digital Subtraction Angiography Research Articles

Should Cerebral Angiography Be Avoided within Three Hours after Subarachnoid Hemorrhage?

ObjectiveWhile the risk of aneurysmal rebleeding induced by catheter cerebral angiography is a serious concern and can delay angiography for a few hours after a subarachnoid hemorrhage (SAH), current angiographic technology and techniques have been much improved. Therefore, this study investigated the risk of aneurysmal rebleeding when using a recent angiographic technique immediately after SAH. MethodsPatients with acute SAH underwent immediate catheter angiography on admission. A four-vessel examination was conducted using a biplane digital subtraction angiography (DSA) system that applied a low injection rate and small volume of a diluted contrast, along with appropriate control of hypertension. Intra-angiographic aneurysmal rebleeding was diagnosed in cases of extravasation of the contrast medium during angiography or increased intracranial bleeding evident in flat-panel detector computed tomography scans. ResultsIn-hospital recurrent hemorrhages before definitive treatment to obliterate the ruptured aneurysm occurred in 11 of 266 patients (4.1%). Following a univariate analysis, a multivariate analysis using a logistic regression analysis revealed that modified Fisher grade 4 was a statistically significant risk factor for an in-hospital recurrent hemorrhage (p =0.032). Cerebral angiography after SAH was performed on 88 patients ≤3 hours, 74 patients between 3–6 hours, and 104 patients >6 hours. None of the time intervals showed any cases of intra-angiographic rebleeding. Moreover, even though the DSA ≤3 hours group included more patients with a poor clinical grade and modified Fisher grade 4, no case of aneurysmal rebleeding occurred during erebral angiography. ConclusionDespite the high risk of aneurysmal rebleeding within a few hours after SAH, emergency cerebral angiography after SAH can be acceptable without increasing the risk of intra-angiographic rebleeding when using current angiographic techniques and equipment.

TU‐H‐CAMPUS‐IeP3‐02: Neurovascular 4D Parametric Imaging Using Co‐Registration of Biplane DSA Sequences with 3D Vascular Geometry Obtained From Cone Beam CT

Purpose:To create 4D parametric images using biplane Digital Subtraction Angiography (DSA) sequences co‐registered with the 3D vascular geometry obtained from Cone Beam‐CT (CBCT).Methods:We investigated a method to derive multiple 4D Parametric Imaging (PI) maps using only one CBCT acquisition. During this procedure a 3D‐DSA geometry is stored and used subsequently for all 4D images. Each time a biplane DSA is acquired, we calculate 2D parametric maps of Bolus Arrival Time (BAT), Mean Transit Time (MTT) and Time to Peak (TTP). Arterial segments which are nearly parallel with one of the biplane imaging planes in the 2D parametric maps are co‐registered with the 3D geometry. The values in the remaining vascular network are found using spline interpolation since the points chosen for co‐registration on the vasculature are discrete and remaining regions need to be interpolated. To evaluate the method we used a patient CT volume data set for 3D printing a neurovascular phantom containing a complete Circle of Willis. We connected the phantom to a flow loop with a peristaltic pump, simulating physiological flow conditions. Contrast media was injected with an automatic injector at 10 ml/sec. Images were acquired with a Toshiba Infinix C‐arm and 4D parametric image maps of the vasculature were calculated.Results:4D BAT, MTT, and TTP parametric image maps of the Circle of Willis were derived. We generated color‐coded 3D geometries which avoided artifacts due to vessel overlap or foreshortening in the projection direction.Conclusion:The software was tested successfully and multiple 4D parametric images were obtained from biplane DSA sequences without the need to acquire additional 3D‐DSA runs. This can benefit the patient by reducing the contrast media and the radiation dose normally associated with these procedures.Partial support from NIH Grant R01‐EB002873 and Toshiba Medical Systems Corp.

Abstract WP67: VESCA: Semi-Automated Segmentation of Cerebral Vasculature in Angiograms

Background: Imaging the cerebrovasculature using digital subtraction angiography (DSA) is a critical step in the diagnosis and treatment of acute stroke. Interpretation and scoring of these DSA images is usually performed by visual review, introducing inter-reader variability that causes inconsistency in clinical trials. Recently, methods have been introduced to automatically quantify various metrics in DSA images, such as revascularization and blush score, and vessel extraction algorithms are often used as part of these methods. However, the results of those algorithms have not been thoroughly evaluated against manually determined groundtruth extraction results, due to a lack of tools for determining the ground truths. Methods: We present a dedicated software tool, VESCA (Vessel Segmentation for Cerebral Angiograms), for manually determining the groundtruths of DSA images to better evaluate vessel detection methods. VESCA interface allows the user to view and segment DSA images, producing a segmented, binary representation of the vasculature. The segmentation process is semi-automated thanks to the livewire segmentation technique, whereby user-selected points along vessel boundaries are automatically connected via the lowest cost path. Results: We have segmented angiograms from a database of 115 biplane DSA, resulting in a set of binary representations of the vessels. We are constructing a web-based system through which other researchers may access the database, and through which they may use the software to contribute segmented images. Conclusion: VESCA is simple to operate and requires minimal instruction. We anticipate that it will facilitate the development and improvement of automatic methods for quantitative DSA image analysis.

Abstract 102: Coregistration of Serial Angiograms Using Point Cloud Matching

Introduction: Digital subtraction angiography (DSA) is the gold standard to assess reperfusion during endovascular procedures. Visualization and quantification of changes between successive runs is challenged by patient motion and variations in acquisition parameters such as zoom and pose of the x-ray receptor. Automated coregistration of successive DSA sequences would allow for the visualization of serial changes in perfusion during the procedure. The objective of this study is to develop a fully automated framework for the coregistration of patient-specific DSA acquired at different time points during an endovascular reperfusion procedure. Methods: The dataset was established retrospectively from patients admitted at a stroke care center and diagnosed with acute ischemic stroke. Included patients underwent a clot retrieval procedure. Biplane DSA was performed before and after endovascular reperfusion intervention. A neurologist manually coregistered the anterior-posterior (AP) view of successive DSA sequences from each patient using anatomical reference landmarks. The developed computer vision framework processed each DSA to extract the vasculature using a vessel detector, followed by resampling of the responses. The resulting set of points in the pre- and post-intervention DSA were then matched using a point cloud matching algorithm. In this study, we provide an experimental analysis with the conventional RANSAC algorithm. Evaluation was performed by measuring the error between the estimated affine transform, that relates the pre- to the post-intervention DSA, and the groundtruth established manually. Results: A total of 20 patients were included in the analysis. Mean age was 66.8 (range 34-91). Distribution of the TICI scores was as follows: TICI 0(3), TICI 1(0), TICI 2a(5), TICI 2b(10), TICI 3(2). Overall coregistration error was as follows: angle (8.6+- 3.1 degrees), shift (24.8 +- 19 mm), respectively. Conclusions: RANSAC point cloud matching algorithm can be used to accurately coregister serial angiograms during endovascular procedures. This could lead to near real-time visualization and quantification of revascularization.

Image Noise Reduction Algorithm for Digital Subtraction Angiography: Clinical Results

Purpose To test the hypothesis that an image noise reduction algorithm designed for digital subtraction angiography (DSA) in interventional neuroradiology enables a reduction in the patient entrance dose by a factor of 4 while maintaining image quality. Materials and Methods This clinical prospective study was approved by the local ethics committee, and all 20 adult patients provided informed consent. DSA was performed with the default reference DSA program, a quarter-dose DSA program with modified acquisition parameters (to reduce patient radiation dose exposure), and a real-time noise-reduction algorithm. Two consecutive biplane DSA data sets were acquired in each patient. The dose-area product (DAP) was calculated for each image and compared. A randomized, blinded, offline reading study was conducted to show noninferiority of the quarter-dose image sets. Overall, 40 samples per treatment group were necessary to acquire 80% power, which was calculated by using a one-sided α level of 2.5%. Results The mean DAP with the quarter-dose program was 25.3% ± 0.8 of that with the reference program. The median overall image quality scores with the reference program were 9, 13, and 12 for readers 1, 2, and 3, respectively. These scores increased slightly to 12, 15, and 12, respectively, with the quarter-dose program imaging chain. Conclusion In DSA, a change in technique factors combined with a real-time noise-reduction algorithm will reduce the patient entrance dose by 75%, without a loss of image quality. © RSNA, 2013

Image Noise Reduction Algorithm for Digital Subtraction Angiography: Clinical Results

To test the hypothesis that an image noise reduction algorithm designed for digital subtraction angiography (DSA) in interventional neuroradiology enables a reduction in the patient entrance dose by a factor of 4 while maintaining image quality. This clinical prospective study was approved by the local ethics committee, and all 20 adult patients provided informed consent. DSA was performed with the default reference DSA program, a quarter-dose DSA program with modified acquisition parameters (to reduce patient radiation dose exposure), and a real-time noise-reduction algorithm. Two consecutive biplane DSA data sets were acquired in each patient. The dose-area product (DAP) was calculated for each image and compared. A randomized, blinded, offline reading study was conducted to show noninferiority of the quarter-dose image sets. Overall, 40 samples per treatment group were necessary to acquire 80% power, which was calculated by using a one-sided α level of 2.5%. The mean DAP with the quarter-dose program was 25.3% ± 0.8 of that with the reference program. The median overall image quality scores with the reference program were 9, 13, and 12 for readers 1, 2, and 3, respectively. These scores increased slightly to 12, 15, and 12, respectively, with the quarter-dose program imaging chain. In DSA, a change in technique factors combined with a real-time noise-reduction algorithm will reduce the patient entrance dose by 75%, without a loss of image quality.

Initial experience with a combined multidetector CT and biplane digital subtraction angiography suite with a single interactive table for the diagnosis and treatment of neurovascular disease

BackgroundA combined imaging suite is useful in the diagnosis and treatment of vascular disease involving the head and neck. This study demonstrates the utility of a multidetector row CT and...

Stentoplasty (Cemented kyphoplasty with Stent) Under Biplane Digital Subtraction Angiography (Biplane DSA)

Vertebral body augmentation with cement such as vertebroplasty and kyphoplasty are well established minimally invasive treatment options for osteoporotic and pathological vertebral compression fracture with highly successful results. The original technique of injection of polymethylmethacrylate (PMMA) bone cement into the compressed vertebral body directly is called “Vertebroplasty”. This technique proved to be a useful approach that could significantly reduce back pain immediately and help the aging patient return to normal activity in a few days with less morbidity than open internal fixation. However, injecting the bone cement directly into the vertebral compression fragment “vertebroplasty” cannot well restore the height of that compressed vertebra, which can cause segmental kyphosis. Biomechanical and clinical data show that the segmental kyphosis resulting from compression fractures, leads to an increased fracture risk of the adjacent vertebral levels,1, 2 that can cause recurrent pain, deformity and disability in the future. Vertebroplasty has no intrinsic mechanical method to restore vertebral height but relies on the elasticity of the fracture itself and patient positioning to induce lordosis. Also, the directed injection of bone cement into non-homogenous space of vertebral fragments can cause a high rate of extra-vertebral leakage that can lead to tremendous complications such as cord compression, embolism, neuropathic pain, paralysis or even death.

In vivo imaging of rat coronary arteries using bi-plane digital subtraction angiography

Introduction X-ray based digital subtraction angiography (DSA) is a common clinical imaging method for vascular morphology and function. Coronary artery characterization is one of its most important applications. We show that bi-plane DSA of rat coronary arteries can provide a powerful imaging tool for translational safety assessment in drug discovery. Methods A novel, dual tube/detector system, constructed explicitly for preclinical imaging, supports image acquisition at 10 frames/s with 88-micron spatial resolution. Ventilation, x-ray exposure, and contrast injection are all precisely synchronized using a biological sequence controller implemented as a LabVIEW application. A set of experiments were performed to test and optimize the sampling and image quality. We applied the DSA imaging protocol to record changes in the visualization of coronaries and myocardial perfusion induced by a vasodilator drug, nitroprusside. The drug was infused into a tail vein catheter using a peristaltic infusion pump at a rate of 0.07 mL/h for 3 min (dose: 0.0875 mg). Multiple DSA sequences were acquired before, during, and up to 25 min after drug infusion. Perfusion maps of the heart were generated in MATLAB to compare the drug effects over time. Results The best trade-off between the injection time, pressure, and image quality was achieved at 60 PSI, with the injection of 150 ms occurring early in diastole (60 ms delay) and resulting in the delivery of 113 μL of contrast agent. DSA images clearly show the main branches of the coronary arteries in an intact, beating heart. The drug test demonstrated that DSA can detect relative changes in coronary circulation via perfusion maps. Conclusions The methodology for DSA imaging of rat coronary arteries can serve as a template for future translational studies to assist in safety evaluation of new pharmaceuticals. Although x-ray imaging involves radiation, the associated dose (0.4 Gy) is not a major limitation.

Impact of percutaneous coronary intervention on health related quality of life in acute coronary syndrome patients

Background: Acute limb ischemia occurs in approximately 150,000 patients and could lead to serious morbidity including need for amputation. Development of effective catheter-based therapies for acute limb ischemia requires adequate in vivo testing. There is clearly a need for a large animal model for effective in vivo testing of intra-arterial thrombolytics and distal embolic protection devices to be used in the treatment of acute limb ischemia. Methods: Institutional Animal Care and Usage Committee approval was obtained. Transarterial transfemoral biplane digital subtraction angiography was performed in a 95-lb Yorkshire swine under anesthesia. Quantitative measurement of vessel diameters in swine was performed to select vessels that mimic human infrapopliteal vessels. Intra-arterial injection (over 30 s) of 20 U (2054 NIH U/mg) of porcine thrombin was used to create a sitespecific clot under transient flow arrest (1 min) using a nondetachable balloon catheter. Intra-arterial thrombolysis was performed using 1 mg (2.09 mg/ml) of human plasmin. Serial angiography was performed to assess the stability of the clot as well as the response to intra-arterial thrombolysis. Results: Peripheral arterial diameters in swine ranged from 1.65 to 4.8 mm: external iliac (4.8 mm), common femoral (3.4 mm), infrapopliteal (3.03 mm), deep femoral (2.58 mm), geniculate (1.79 mm), tibial (1.91 mm), and dorsalis pedis (1.65 mm). Serial angiography after injection of porcine thrombin revealed occluded infrapopliteal artery exhibiting rapid onset of clot development (2.5 min) and its mechanical stability (30 min). SHELTER, a novel distal embolic protection device, was safely deployed distal to the clot and intra-arterial thrombolysis was performed. Follow-up angiography revealed partial revascularization. The embolic protection device was safely removed. Conclusion: This large animal porcine model allows for using a sitespecific, reliable, and rapid method of creation and lysis of blood clots within the small peripheral vessels and could be useful in the development and preclinical evaluation of catheter-based endovascular therapies for acute limb ischemia.

Role of biplane digital subtraction angiography, and 3D rotational angiography in craniopagus twins: A case report, detailed pictorial evaluation, and review of literature

Cranially conjoined twins (craniopagus) are regarded as one of the rarest human malformations. Craniopagus represents 2 to 6% of conjoined twins and is the rarest type of disorder. A conventional angiogram with three dimensions is needed to confirm the exact extent of sharing of the arterial / venous tree. 3D angiography was first proposed by CORNELIUS and advanced into clinical practice by VOIGT in 1975. We present a case of craniopagus vertical type II twins, evaluated for cerebral circulation.

Endovascular operating suite: future directions for treating neurovascular disease

The purpose of this study was to evaluate initial experiences in a surgical operating room (OR) with a multipurpose angiography unit, which offers integrated neurosurgical and radiological capabilities. A specially designed biplane digital subtraction (DS) angiography system was installed in the neurosurgery OR. The new suite, which allows three-dimensional DS angiography with C-arm for computerized tomography and microsurgery capabilities, allows the neurosurgeon to perform a wide range of neurosurgical and endovascular procedures. Three hundred thirty-two procedures were performed in the endovascular OR between November 2003 and March 2005. Patients arriving in the emergency department were transferred to the endovascular OR without delay. The neurovascular team performed diagnostic angiography followed by endovascular interventional procedures or surgery. The newly designed endovascular OR facilitates safe and systemic treatment of neurovascular disease.

Assessment of vasospasm in experimental subarachnoid hemorrhage in rats by selective biplane digital subtraction angiography

Although the rat subarachnoid hemorrhage model is well established in vasospasm research, the angiographic evaluation is difficult due to the animal's small size. For this reason, the aim of the study was to develop a standardized angiographic examination technique without additional complex equipment. Under general anesthesia, 11 Sprague-Dawley rats underwent selective cerebral digital subtraction angiography using a 0.3 mm focal spot and a 2.0-fold linear magnification. Five animals had experimental subarachnoid hemorrhage according to the "double-hemorrhage" model. Comparison with the intraarterial tip of the microcatheter enabled calibration of the vessel lumen. The diameter of the normal basilar artery (n=6) was 0.34+/-0.03 mm (mean+/-SD), whereas delayed vasospastic constriction (mean 6.2 days) caused a reduction in diameter of 32.4% (0.23+/-0.09 mm) as well as impaired collateral blood flow via the posterior communicating artery and anterior spinal artery. Histological examination of sections stained with hematoxylin and eosin under a light microscope confirmed vasospasm. In conclusion, biplane digital subtraction angiography allows precise and reliable evaluation of arterial diameter reduction and hemodynamic parameters in a rat vasospasm model. However, further investigation is required for assessment of vasoactive drugs, e.g., endothelin receptor antagonists.

Endovascular Treatment of Brain Arteriovenous Malformations: The Toronto Experience

The University of Toronto Brain VascularMalformation Group keeps a database on allBAVM patients evaluated and treated by thegroup. The data was collected retrospectivelyform 1984 to 1991 and from then prospectively.Currently 973 patients diagnosed with BAVMare registered in the database.All endovascularprocedures were carried out at the TorontoWestern Hospital and The Hospital for SickChildren. Patients with Vein of Galen malfor-mations and cranial dural arteriovenous fistu-las were excluded from this analysis. Two peri-ods were analysed 1984-1993 and 1994-2004.Analyzed data includes demographic informa-tion, clinical presentation, initial neurologicalexamination, technical aspects of the endovas-cular procedure, complications and outcomes.Complications related to embolization weredefined as occurring within one month of theprocedure. The severity of any complicationswas assessed with the Modified Rankin Scale(MRS). The purpose of the embolization wasclassified as an attempt to cure, pre-radiation,pre-operative or palliative treatment.From 1984 to 1994 almost all embolizationprocedures were performed under neuroleptanesthesia. Since 1995, general anesthesia hasbeen routinely employed, and biplane digitalsubtraction angiography has been used since1999.All patients are systemically anticoagulat-

Microcatheter embolization of intractable idiopathic epistaxis.

To assess the efficacy and safety of microcatheter embolization in the treatment of intractable idiopathic epistaxis. Thirty-seven patients underwent microcatheter embolization in 1991-1998. We evaluated retrospectively the technical and clinical outcome, the number of complications, the duration of embolization in each case, and the number of blood transfusions needed. All embolizations were done with biplane digital subtraction angiography (DSA) equipment. The procedure was carried out under local anesthesia using transfemoral catheterization, except in one case where the translumbar route was used. Tracker 18 or 10 microcatheters were advanced as far as possible to the distal branches of the sphenopalatine artery. Polyvinyl alcohol (PVA) particles were used for embolization in most cases, while platinum coils or a combination of these two materials were occasionally used. The primary outcome was always assessed immediately by angiography. Follow-up data were obtained from patient records, by interviewing patients on the telephone or by postal questionnaires when necessary. The mean follow-up time was 21 months. The embolization was technically successful in all 37 cases. A curative outcome was achieved in 33 cases (89%). The mean duration of the procedure was 110 min. Four patients (8%) had mild transient complications, but no severe or persistent complications were encountered. Twenty-three patients needed a blood transfusion. Slight rebleeding occurred in three patients during the follow-up; all responded to conservative treatment. One patient suffered two episodes of rebleeding within 2 months after primary embolization. Re-embolizations successfully stopped the bleeding. Embolization is the primary invasive modality for treating intractable idiopathic epistaxis. It proved both safe and effective over a relatively long follow-up.

Angiographic Analysis of the Circle of Willis: Comparison between Atherosclerosis and Normal Groups

Purpose : To determine differences in angiographic variations of the circle of Willis between atherosclerosis and normal groups. Materials and Methods : In 289 patients we reviewed complete cerebral angiograms obtained using biplane digital subtraction angiography. Atherosclerosis was diagnosed in 189 patients, while 100 were normal. Patients were divided into four subgroups according to the relative size of each segment and the presence of cross-filling of opposite-sided vessels. When the circle was completely present, we determined whether or not it was balanced, and statistically compared variation patterns between the two groups. Results : In the atherosclerosis group, the anterior half of the circle was complete in 74% of cases(139/189), and the posterior half in 38% (72/189). In the normal group, the anterior half was complete in 90% of cases, and the posterior half in 63%. An incomplete circle was more common in the atherosclerosis group than among normal subjects (26% vs 10%, p.05) and agenesis of the P1 segment (7% vs 3%, p>.05). Conclusion : An incomplete and unbalanced circle of Willis was more common in the atherosclerosis group than in the normal group. Agenesis of the anterior communicating artery, the A1 segment, or the posterior communicating artery was common in the atherosclerosis group, as was size discrepancy between A1 segments.

Neuroradiological applications of a new system of stereoscopic biplane digital subtraction angiography.

A stereoscopic biplane digital subtraction angiography (DSA) system was developed, capable of obtaining frontal and lateral projections simultaneously during a single injection of contrast medium. This new system combines the advantages of both biplane and stereoscopic single-plane DSA, and permits high-quality neuroangiography.

Neuroradiological applications of a new system of stereoscopic biplane digital subtraction angiography

Neuroradiological applications of a new system of stereoscopic biplane digital subtraction angiography

Biplane digital subtraction angiography

Biplane digital subtraction angiography was performed by placing a rapid switch between the anteroposterior and lateral T.V. cameras and the A-D converter. Alternate exposures from two X-ray tubes were employed. Excellent anteroposterior and lateral DSA was obtained especially for the brain and neck. Although there was more time required for positioning, biplane imaging saved the second or the third injection in many occasions. The technique has been especially valuable for intravenous DSA of the brain and the neck.

Technical developments and instrumentation: Biplane digital subtraction angiography

Biplane digital subtraction angiography was utilized in 200 patients having intravenous or intra arterial studies. Images were of excellent quality without cross fogging by scattered radiation using an alternating exposure series. Decreased contrast load and decreased procedure time were significant benefits.