Rotational Angiography Research Articles

Ventral Clival Branch of the Ascending Pharyngeal Artery as aTransosseous Feeder of an Arteriovenous Fistula Surrounding the Clival Lesions.

Arteriovenous fistulas (AVFs) adjacent to the clivus, such as cavernous sinus dural AVFs (CSDAVFs) and condylar AVFs, sometimes have an intraosseous shunted pouch and recruit blood supply from transosseous feeders. Precise analysis of transosseous feeders regarding the clival lesion has not yet been performed. Therefore, this study aimed to clarify the characteristics and identity of transosseous feeders in clival lesions. Patients with CSDAVFs and condylar AVFs, who underwent high-resolution cone-beam computed tomography or three-dimensional rotational angiography in our institute, were included. The frequency, type of branch, penetrating point, and termination of intraosseous feeders were retrospectively evaluated. Atotal of 31patients with 36 lesions in CSDAVFs and 8 patients with 8 lesions in condylar AVFs underwent angiography. For CSDAVFs, 38transosseous feeders were detected in 23 out of 31patients, including 22 in the pharyngeal branch of the ascending pharyngeal artery (APhA), 6in the hypoglossal branch of the APhA, 6 in the accessory meningeal artery, 3in the meningohypophyseal trunk (MHT), and 1 in the anterior branch of the middle meningeal artery. For condylar AVFs, 24transosseous feeders were detected in all 8 patients, including 11 in the pharyngeal branches of the APhA, 7in the hypoglossal branch of the APhA, 6in the segmental artery from the vertebral artery, and 2 in the MHT. Transosseous feeders of AVFs around the clivus, which are frequently seen in AVFs of this area, mainly arise from ventral clival branches and from pharyngeal branches of the APhA.

Dural arteriovenous fistula of the craniocervical junction along the first cervical nerve: A single-center experience and review of the literature

BackgroundDural arteriovenous fistulas (DAVFs) of the craniocervical junction (CCJ) are relative rare lesions. Most studies of DAVFs of the CCJ included the fistulas at the foramen magnum, first cervical (C1), and second cervical (C2) level. DAVFs of the CCJ along C1 spinal nerve are rare vascular lesions with distinctive features. Our aim is to review cases of DAVFs of the CCJ along C1 spinal nerve at our institution. MethodsFrom June 2008 and December 2021. We reviewed a consecutive series of intracranial and spinal DAVFs at our institution and collected all patients harboring DAVFs of the CCJ along C1 spinal nerve. Medical charts were retrospectively reviewed regarding patient demographic data (i.e., gender and age), presenting symptoms and signs, treatment methods, and neurological outcome and complications after treatment. All image studies, including cranial computed tomography (CT) scan, cervical magnetic resonance imaging, CT angiography, and digital subtraction angiography (DSA) with rotational CT angiography were analyzed by experienced neuroradiologists. The authors also review of the literature of DAVFs of the C1 spinal nerve. ResultsThe authors identified 7 patients, including 5 men (71.4 %) and 2 women (28.6 %) with median age 54 years, range 48–72 years. Subarachnoid hemorrhage (SAH) occurred in 5 (71.4 %) patients, and progressive myelopathy in 2 (28.6 %). All fistulas except one received blood supply from the radiculomeningeal branch of the VA at C1 level. Venous aneurysms, being the source of bleeding, were detected in all fistulas with SAH. All patients except one were treated by surgical management. One fistula was treated by balloon-assisted Onyx embolization. Most patients had good neurological outcome following surgery. Complete obliteration of all fistulas treated by surgery was confirmed by follow-up DSA obtained 1 week after surgery. Two patients developed temporary pain and spasm of the trapezius muscle after the surgery. One patient resulted in poor neurological outcome and died due to sepsis and acute upper gastrointestinal bleeding one month after failed embolization. For patients with SAH, only one patient required ventriculoperitoneal shunt. ConclusionsDAVFs of the CCJ along the first spinal nerve are rare and a unique subtype of DAVFs at the CCJ. These fistulas account for 1.74 % of all intracranial and spinal DAVFs in the present study. SAH is the major manifestation of DAVFs at C1 spinal nerve that may be overlooked on routine initial DSA. Rotational CT angiography is useful for clarification of the angioarchitecture of these fistulas, including small feeding artery and venous varix. Surgical treatment by interruption of the intradural draining vein should be the treatment of choice for C1 spinal nerve DAVF

Correlation of aortic valve annular plane assessment by on-table three-dimensional rotational angiography and preprocedural computed tomography.

To assess the correlation between the aortic valve annular plane (AVAP) obtained by preprocedural computed tomography (CT) with on-table three-dimensional rotational angiography (3DRA), in patients undergoing transcatheter aortic valve replacement (TAVR). Accurate assessment of the AVAP is critical during TAVR procedures to enable optimal positioning and minimize complications. Most commonly, preprocedural CT has been used to determine the AVAP. However, this can differ from the actual AVAP obtained during the TAVR procedure. Consecutive TAVR patients at a single center undergoing both preprocedural CT and 3DRA were included in the study. The AVAP assessment by CT was performed using 3mensio software (Pie Medical Imaging). 3DRA assessment was performed using DynaCT (Siemens). A total of 100 patients were included in the analysis. A difference of ≥5° and ≥10° in both the LAO/RAO and cranial/caudal components of the AVAP projection angle as assessed by CT and 3DRA was recorded in 39% and 10% of patients, respectively. The concordance correlation coefficient for the LAO/RAO and cranial/caudal implantation angles was 0.519 (95% CI: 0.377-0.661) and 0.558 (95% CI: 0.432-0.684), respectively. Correlation between preprocedural CT and on-table 3DRA in the prediction of the actual AVAP at the time of TAVR implantation is moderate.

Rotational coronary angiography as a safe and effective method

Rotational coronary angiography as a safe and effective method

Visualization of Cerebrospinal Micro-Angioarchitecture

Researchers have been trying to visualize fine angioarchitecture in cerebrospinal vascular lesions and the positional relationship between vascular lesions and surrounding structures. The aim of this article was to introduce the usefulness of imaging in visualizing the microvascular anatomy in cerebrospinal vascular lesions, such as aneurysm, arterial dissection, arteriovenous malformation, dural arteriovenous fistula(AVF), spinal dural and epidural AVF, and craniocervical junction AVF. For the imaging modality, we used high-resolution magnetic resonance imaging, three-dimensional rotational angiography(3D-RA), slab maximum intensity projection image from 3D-RA, cone-beam computed tomography, and fusion imaging. If fully exploited, imaging can contribute to clinical analysis and surgical treatment and be an essential tool for achieving maximum therapeutic effect without complications.

Prognosis of Rotational Angiography-Based Stereotactic Radiosurgery for Dural Arteriovenous Fistulas: A Retrospective Analysis.

Cerebral dural arteriovenous fistulas (DAVFs) are intracranial vascular malformations with fine, abnormal vascular architecture. High-resolution vascular imaging is vital for their visualization. Currently, rotational angiography (RA) provides the finest 3-dimensional visualization of the arteriovenous shunt with high spatial resolution; however, the efficacies of the integration of RA have never been studied in stereotactic radiosurgery (SRS) for DAVFs until now. Since 2015, our institution has integrated RA into SRS (RA-SRS) to provide more conformal planning, thereby decreasing overtreatment and undertreatment. To analyze the outcomes of RA-SRS for DAVFs. We retrospectively analyzed the outcomes of 51 patients with DAVFs and compared those of 20 DAVFs treated with RA-SRS with those of 31 DAVFs treated with conventional SRS (c-SRS). The time to obliteration was shorter in the RA-SRS group (median, 15 months vs 26 months [cumulative rate, 77% vs 33% at 2 years, 77% vs 64% at 4 years]; P = .015). Multivariate Cox proportional hazards analysis demonstrated that RA-SRS (hazard ratio 2.39, 95% CI 1.13-5.05; P = .022) and the absence of cortical venous reflux (hazard ratio 2.12, 95% CI 1.06-4.25; P = .034) were significantly associated with obliteration. The cumulative 5-year post-SRS stroke-free survival rates were 95% and 97% in the RA-SRS and c-SRS groups, respectively ( P = .615). Neurological improvement tended to occur earlier in the RA-SRS group than in the c-SRS group (median time to improvement, 5 months vs 20 months, log-rank test; P = .077). RA-based SRS may facilitate earlier fistula obliteration and may contribute to early neurological improvement.

Angioarchitecture of the Normal Lateral Spinal Artery and Craniocervical Junction Arteriovenous Fistula Using Contrast-enhanced Cone-beam CT.

The lateral spinal artery (LSA) perfuses the dorsolateral part of the spinal cord at the craniocervical junction (CCJ). We analyzed the angioarchitecture of the normal LSA and CCJ arteriovenous fistula (AVF). The first study included 26patients with acerebral aneurysm of the posterior circulation. Using slab maximum intensity projection (MIP) images from three-dimensional rotational angiography (3D-RA) and contrast-enhanced cone-beam CT (CE-CBCT), we analyzed the origin of the LSA, its anastomosis with the posterior inferior cerebellar artery (PICA), the point where it reaches the spinal cord, and the visualized range. In the second study, we analyzed the angioarchitecture and treatment results of 7 CCJAVF lesions treated in our department between 2016 and 2021. We visualized the normal LSA for all patients. In 23patients with an intradural origin PICA, all LSAs originated from the C1 or C2 radicular artery, and 8 patients had an anastomosis with the PICA. In three patients with aC1 level origin PICA, all LSAs originated from the PICA. All LSAs reached the dorsolateral part of the spinal cord. The mean visualized range of the LSA was 27.4 mm. The LSA was involved in five of seven CCJAVF lesions (71%). There was one lesion with aspinal infarction after LSA embolization. Other lesions were treated by direct interruption of the AVF, and the ASA and LSA were preserved. This is the first report that visualized the LSA's normal anatomy using slab MIP images from 3D-RA and CE-CBCT. Knowledge of LSA anatomy is critical to avoid complications during the treatment of CCJAVF.

The veins of the left ventricular summit in patients undergoing cardiac resynchronization therapy

Abstract Introduction While the coronary sinus and its left ventricular branches have been extensively described, the veins of the left ventricle summit (LVS) have been much less studied. The emergence of new ablation techniques for ventricular tachycardias, which make use of the LVS veins, has generated a renewed interest in the anatomy of these venous conduits. Purpose The aim of the study was to describe in detail the anatomy of the LVS veins using rotational venous angiography. Material and methods All patients (N=106, age 68±12 years, 72 men) underwent coronary venous angiography during the cardiac resynchronization implant procedures. Results The LVS veins identified were the great cardiac vein (GCV), the anterior interventricular vein (AIV) and the mitro-aortic LVS vein (MALVSV). The MALSV emerged from the GCV between 12 and 2 o'clock on the mitral ring, coursed inside the left atrioventricular groove, towards the aorto-mitral continuity (AMC), where it turned towards the ventricular septum and coursed parallel to the AIV, tapered down and ended at midventricular level. Most of the course of this vein was in the region of the LVS. The diameter of the venous conduit at the GCV-AIV junction was 4.9±1.0 mm. The MALVSV was present in 76 patients (72%; Figure 1). The MALVSV diameter was 2.4±0.6mm at the ostium (Figure 2) and 1.8±2.0 mm at the AMC. The takeoff angle was 134±27°. The total length of the vein was 34±16 mm, of which 23±14mm were inside the AV groove and 11±9mm, were along the ventricular septum. The length of the MALSV segment embedded in the left AV groove as well as the total length of MALSV correlated significantly with the left atrial diameter (r=0.44; P=0.040 and r=0.45; p=0.016 respectively) as well as with the right ventricular systolic pressure (r=0.50; p=0.028 and r=0.57; P=0.030 respectively). Conclusions This study brings new insights into the angiographic anatomy of the LVS veins. Detailed knowledge of these venous tributaries could help with the development of new strategies for ablation of LVS tachycardias. Funding Acknowledgement Type of funding sources: None.

Self-supervised learning enables 3D digital subtraction angiography reconstruction from ultra-sparse 2D projection views: A multicenter study

Summary3D digital subtraction angiography (DSA) reconstruction from rotational 2D projection X-ray angiography is an important basis for diagnosis and treatment of intracranial aneurysms (IAs). The gold standard requires approximately 133 different projection views for 3D reconstruction. A method to significantly reduce the radiation dosage while ensuring the reconstruction quality is yet to be developed. We propose a self-supervised learning method to realize 3D-DSA reconstruction using ultra-sparse 2D projections. 202 cases (100 from one hospital for training and testing, 102 from two other hospitals for external validation) suspected to be suffering from IAs were conducted to analyze the reconstructed images. Two radiologists scored the reconstructed images from internal and external datasets using eight projections and identified all 82 lesions with high diagnostic confidence. The radiation dosages are approximately 1/16.7 compared with the gold standard method. Our proposed method can help develop a revolutionary 3D-DSA reconstruction method for use in clinic.

Validation of SART 3.5D algorithm for cerebrovascular dynamics and artery versus vein classification in presurgical 3D digital subtraction angiographies

Classification of arteries and veins in cerebral angiograms can increase the safety of neurosurgical procedures, such as StereoElectroEncephaloGraphy, and aid the diagnosis of vascular pathologies, as arterovenous malformations. We propose a new method for vessel classification using the contrast medium dynamics in rotational digital subtraction angiography (DSA). After 3D DSA and angiogram segmentation, contrast enhanced projections are processed to suppress soft tissue and bone structures attenuation effect and further enhance the CM flow. For each voxel labelled as vessel, a time intensity curve (TIC) is obtained as a linear combination of temporal basis functions whose weights are addressed by simultaneous algebraic reconstruction technique (SART 3.5D), expanded to include dynamics. Each TIC is classified by comparing the areas under the curve in the arterial and venous phases. Clustering is applied to optimize the classification thresholds. On a dataset of 60 patients, a median value of sensitivity (90%), specificity (91%), and accuracy (92%) were obtained with respect to annotated arterial and venous voxels up to branching order 4–5. Qualitative results are also presented about CM arrival time mapping and its distribution in arteries and veins respectively. In conclusion, this study shows a valuable impact, at no protocol extra-cost or invasiveness, concerning surgical planning related to the enhancement of arteries as major organs at risk. Also, it opens a new scope on the pathophysiology of cerebrovascular dynamics and its anatomical relationships.

Diagnostic Performance of 0.55 T MRI for Intracranial Aneurysm Detection.

Intracranial aneurysm (IA) is the main cause of subarachnoid hemorrhages. Time-of-flight (TOF) magnetic resonance angiography (MRA) at 1.5 T or 3 T magnetic resonance imaging (MRI) is a well-established method for the diagnosis of IA. The aim of this prospective study was to evaluate the performance of a modern 0.55 T MRI in the diagnosis of IAs in comparison to digital subtraction angiography (DSA) as a standard of reference. Seventeen patients with suspicion of single or multiple IAs underwent TOF MRA at 0.55 T MRI 1 day before DSA. Two neuroradiologists independently measured the aneurysm neck, width, and height on 0.55 T, 1.5 T, and 3 T 3D-TOF MRA source images and 2D/3D rotational angiography. The main analysis assessed the intermodality agreement between 0.55 T TOF MRA and DSA using Bland-Altman plots, a Wilcoxon test, and the intraclass correlation coefficient (ICC). In a secondary analysis, aneurysm dimensions were compared between 0.55 T TOF MRA and 1.5/3 T TOF MRA. Interreader agreement was evaluated by ICC. A third neuroradiologist blinded to patient history screened 0.55 T TOF MRA data sets of the aforementioned 17 patients and 15 additional healthy patients for the presence and location of aneurysms. A total of 19 aneurysms in 16 patients were identified in both 0.55 T MRA and DSA. Measurements of the 2 nonblinded readers showed no significant differences between 0.55 T TOF MRA and DSA in the overall aneurysm size (calculated as the mean from height/width/neck) ( P = 0.178), as well as in the mean width ( P = 0.778) and neck values ( P = 0.190). The mean height was significantly larger in 0.55 T TOF MRA in comparison to DSA ( P = 0.020). Intermodality (1.5/3 T TOF MRA) and interrater agreement were excellent (ICC > 0.94). Of the 32 data sets of patients with and without IA, the blinded reader detected all aneurysms correctly by using 0.55 T images. TOF-MRA acquired with a modern 0.55 T MRI is a reliable tool for the detection and initial assessment of IAs.

A Prospective Study Comparing the Three-Dimensional Rotational Angiography and Two-Dimensional Digital Subtraction Angiography in Evaluation of Brain Arteriovenous Malformations.

Complex angioarchitecture of brain arteriovenous malformations (BAVM) are often difficult to evaluate with standard imaging technique of digital subtraction angiography (DSA). These details are better provided by 3D rotational angiography (3D-RA). The aim of the study is to compare two-dimensional digital subtraction angiography (2D-DSA) and 3D rotational angiography in the evaluation of BAVM angiographic architecture. 2D-DSA and 3D-RA of 167 consecutive patients with BAVM were analyzed for arterial feeders, nidal patterns, and detection of flow-related aneurysms, arteriovenous fistulous components, venous drainage, and draining vein stenosis. 3D-RA detected a significantly higher number of aneurysms and draining venous stenoses (P < 0.001). The detected number of true intranidal aneurysms was significantly higher with 3D-RA (n = 94) vs 2D-DSA (n = 34) (P < 0.001). 2D-DSA has low sensitivity (43.1%) and specificity (73.4%) for detecting intranidal aneurysms. 3D-RA detected a significantly higher number (12.6%) of BAVM patients with feeding artery aneurysms as compared to 2D-DSA (8.4%), P value of 0.004. 3D-RA accurately depicted the distal course of dominant arterial feeders and fistulous sites in BAVMs. Direct arteriovenous communications were evident in 31.1% with 3D-RA, as compared to 2D-DSA (15%) with P value < 0.0001. A significantly higher number of draining vein stenosis was detected with 3D-RA (21.6%) as compared to 2D-DSA (13.2%), P value < 0.001. 3D-RA is better than 2D-DSA for detecting BAVM-associated flow-related aneurysms, distal course of the dominant arterial feeders, direct visualization of the fistulous components, deep venous drainage, and draining venous stenosis; findings imperative for making a prudent therapeutic decision.

A posterior inferior cerebellar artery aneurysm ruptures during three-dimensional rotational angiography: need to think fast and act faster

A posterior inferior cerebellar artery aneurysm ruptures during three-dimensional rotational angiography: need to think fast and act faster

Radiation dose reduction in the setting of cryoballoon ablation for atrial fibrillation: the value of optimized fluoroscopy settings and intracardiac echocardiography.

Cryoballoon (CB) has proven to be very effective in the percutaneous treatment of atrial fibrillation (AF). CB ablation is still hampered by X-ray exposure and the doses applied are consistently higher if compared to radiofrequency ablation. All patients who underwent CB ablation between 2015 and 2020 were analysed. Intracardiac echography was consistently used for transeptal puncture. To demonstrate the differences in radiation exposure 3 groups of 50 consecutive patients were selected. In the first group (G1) 3D rotational angiography (3DRA) was used as an intraprocedural imaging method. In the second group (G2), traditional X-ray imaging was used and frame rates both for fluoro and cine modes of diascopy were lowered. In the third group (G3) only 2-3 frames per second were used, cine mode was abandoned and the grid was removed from the X-ray detector. A total of 150 patients were included (76% males, mean age 57.3 ± 11.5years). A dramatic reduction of radiation dose was obtained from 9585 ± 5610µGy/m2 in G1 to 2469 ± 2002µGy/m2 in G2 and finally 227.1 ± 360µGy/m2 in G3 (p < 0.0001). There was also a significant decrease of procedural and fluoroscopy times. No difference in major complications and midterm outcomes was found between the groups. By following a few relatively simple steps (omitting the pre-procedural imaging, removing grid from the X-ray detector and using very low frame rates) CB ablation could be performed with ultralow radiation exposure without compromising the safety of efficacy of the procedure.

Optimizing 3D Rotational Angiography for Congenital Cardiac Catheterization.

The aim of the study was to determine the variables associated with high-quality (HQ) versus low-quality (LQ) three-dimensional rotational angiography (3DRA) and create guides for optimization of approach to 3DRA in congenital cardiac catheterization (CCC). CCC has adopted 3DRA as a mainstay, but there has not been systematic analysis of approach to and factors associated with HQ 3DRA. This was a single-center, retrospective study of 3DRAs using Canon Infinix-I platform. Reconstructions were graded by 3 interventionalists. Quality was dichotomized into HQ and LQ. Univariable analyses and multivariable logistic regression models were performed. From 8/2016 to 12/2018, 208 3DRAs were performed in 195 CCCs; median age 7 years (2, 16), weight 23kg (12, 57). The majority of 3DRAs were performed in patients with biventricular physiology (N = 137, 66%) and in pulsatile sites (N = 144, 69%). HQ 3DRA (N = 182, 88%) was associated with greater total injection volume [2.20mL/kg (1.44, 3.29) vs. 1.62mL/kg (1.10, 1.98), p = 0.005] and more dilute contrast solution [60% (50, 100) vs. 100% (60, 100), p = 0.007], but not with contrast volume administered (p = 0.2) on univariable analysis. On multivariable logistic regression, HQ 3DRA was significantly associated with patient weight [OR 0.97 (95% CI (0.94, 0.99), p = 0.018], total injection volume [OR 1.04 (95% CI 1.01, 1.07) p = 0.011], and percent contrast solution [OR 0.97 (95% CI 0.95, 1.00), p = 0.022]. These data resulted in creation of scatter plots and a novel 3DRA Nomogram for estimating the probability of HQ 3DRA. This is the first study to create evidence-basedcontrast dose guides and nomogram for 3DRA in CCC. HQ 3DRA was associated with lower weight, higher total injection volumes, and more dilute contrast solution.

Frameless Co-Registration of Biplane 2D Digital Subtraction Angiography Whole Frames and 3D Rotational Angiography-Based Cone-Beam Computed Tomography Angiogram on Dedicated Software for Stereotactic Radiosurgery of Cranial Vascular Malformations.

Purpose: Given its high spatial resolution and vasculature selectivity, the cone-beam computed tomography (CT) angiography (CBCTA) image acquired by selective 3D rotational angiography (3DRA) is the most suitable 3D image for the target definition of stereotactic radiosurgery (SRS) for intracranial arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). Furthermore, the relatively low temporal resolution of 3DRA-based CBCTA can be complemented by the stereotactic co-registration of orthogonally paired 2D dynamic digital subtraction angiography (2D-DSA). The integration of 2D-DSA, which is usually limited to one or a few frames for each projection, into CBCTA and/or planning CT can be achieved only by catheter-directed angiography on the day of SRS via a dedicated image localizer under rigid frame fixation to the skull, which imposes substantial burdens on patients. This study aimed to demonstrate a novel, convenient, and significantly less invasive method for the frameless co-registration of biplane 2D-DSA whole frames and CBCTA on commercially available dedicated software, namely, Brainlab® Elements (Brainlab AG, Munich, Germany), and present its prerequisite for successful image fusion.Technical Report: Elements have afforded the following functionality: A 3D vasculature image is automatically extracted as a floating image from any 3D image series containing vascular details and then subsequently co-registered manually and automatically to a selected frame pair of 2D-DSA with a six-degree-of-freedom rigid registration. As a preclinical feasibility study, two anonymous image datasets from patients harboring cerebral AVM and transverse-sigmoid (TS) DAVF were used to verify the accuracy and practicality of Elements for the frameless co-registration of 2D/3D vascular images, particularly on the assumption of clinical workflow for the target delineation of SRS planning. The use of ordinary unsubtracted CBCTA resulted in the insufficient extraction of abutting vessels or vessels that are in close proximity to bony structures, particularly in the case of TS-DAVF, where the fistulous pouch and the affected venous sinuses were adjacent to the cranial bone. By contrast, the amount and selectivity of vasculatures and the accuracy of subsequent image fusion were significantly improved from the subtracted CBCTA. The integration of CBCTA into dynamic 2D-DSA allowed the simultaneous review of both image information by sharing any concerning point and 2D or 3D structures under a common 3D coordinate.Conclusions: Elements enable the clinically useful frameless co-registration of biplane 2D-DSA whole frames into CBCTA, for which the routine acquisition of both subtracted and unsubtracted CBCTA axial images for ordinary diagnostic purposes is an indispensable prerequisite for successful image fusion and further widespread application. This frameless integration of the 2D/3D angiogram would dramatically enhance both the frame-based and frameless SRS workflow and circumstances by allowing users to forward SRS planning well in advance before SRS, along with the omission of invasive angiography on the day of SRS, and would broaden the implementation of frameless SRS. Furthermore, the comprehensive alternating interactive review of the 2D/3D integrated angiogram leads to a more in-depth quasi-4D understanding of the affected angioarchitectures compared with the separate viewing of each image.

Non-contrast enhanced silent MR angiography to evaluate hemodynamics and morphology of unruptured intracranial aneurysms: a comparative computational fluid dynamics study

BackgroundSilent MR angiography (silent MRA) is a new generation of non-contrast enhanced angiography with outstanding advantages in visualizing cerebrovascular lesions and the follow-up after endovascular treatment for intracranial aneurysms (IAs)....

Reliability of using generic flow conditions to quantify aneurysmal haemodynamics: A comparison against simulations incorporating boundary conditions measured in vivo

Background and objectivesInitiation, growth, and rupture of intracranial aneurysms are believed to be closely related to their local haemodynamic environment. While haemodynamics can be characterised by use of computational fluid dynamics (CFD), its reliability depends heavily upon accurate assumption of the boundary conditions. Herein, we compared the simulated aneurysmal haemodynamics obtained by use of generic boundary conditions against those obtained under flow conditions measured in vivo. MethodsWe prospectively recruited 19 patients with intracranial aneurysms requiring 3-dimensional rotational angiography, during which blood pressure at the internal carotid artery was probed by catheter and flowrate measured by a dedicated software tool. Using these flow conditions measured in vivo, we quantified the aneurysmal haemodynamics for each patient by CFD, and then compared the results with those derived from a generic condition reported in the literature, in terms of the time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and percentage of the intra-aneurysmal flow (PIAF). In addition, the effects on aneurysmal haemodynamics of different outflow strategies (splitting method vs. Murray's Law) and simulation schemes (transient vs. steady-state) relative to each flow condition were also assessed. ResultsDifferences in the simulated TAWSS (−6.08 ± 10.64 Pa, p = 0.001), OSI (0.06 ± 0.13, p = 0.001), and PIAF (−0.05 ± 0.20, p = 0.012) between the patient-specific and generic boundary conditions were found to be statistically significant, in contrast to that in the RRT (49 ± 307 Pa−1, p = 0.062). Outflow strategies did not yield statistically significant differences in any of the investigated parameters (all p > 0.05); rather, the resulting parameters were found to be in good correlations (all r > 0.71, p < 0.001). Difference between the aneurysmal TAWSS and the WSS derived from cycle-averaged flowrate condition was found to be minor (0.66 ± 1.36 Pa, p = 0.000), so was that between PIAFs obtained respectively from the transient and steady-state simulations (0.02 ± 0.05, p = 0.000). ConclusionsIncorporating into simulation the patient-specific boundary conditions is critical for CFD to characterise aneurysmal haemodynamics, while outflow strategies may not introduce significant uncertainties. Steady-state simulation incorporating the cycle-averaged flow condition may produce unbiased WSS and PIAF compared to the transient analysis.

Feasibility of intraprocedural augmented reality visualisation of 3D rotational angiography in congenital cardiac catheterisation.

Three-dimensional rotational angiography has become a mainstay of congenital cardiac catheterisation. Augmented reality is an exciting and emerging technology that allows for interactive visualisation of 3D holographic images in the user's environment. This case series reports on the feasibility of intraprocedural augmented reality visualisation of 3D rotational angiography in five patients with CHD.

Variations in the branching patterns of the anterior choroidal artery: an angiographic study with special reference to temporal lobe epilepsy surgery.

The preservation of the anterior choroidal artery (AChA) is essential for avoiding neurological sequelae after mesial temporal lobe epilepsy (mTLE) surgery. The purpose of this study is to reveal the anatomical variation in which the perforating branches arise from the plexal segment of the AChA by using a modern neuroimaging modality. This study analyzed 3D rotational angiography (3DRA) images from 56 subjects. The AChA and perforating branches were visualized using slab MIP. We analyzed branching patterns, courses of the perforating arteries arising from the plexal segment of the AChA, and the anastomosis of the AChA with other cerebral arteries. The slab MIP applied to 3DRA visualized one or more perforating branches from the AChA in 92.9% of cases. The presence of perforating branches arising from the AChA plexal segment was 17.3%. Most of the branching points of plexal perforators were likely located in the operative field during hippocampal resection. The course of the AChA plexal perforators included the posterior limb of the internal capsule. Anastomosis with other cerebral arteries was visualized in 25% of the AChA with plexal perforators. 3DRA slab MIP was useful for visualizing the perforating branches of the AChA. Our results showed the possibility that surgical manipulation of the choroid plexus may cause infarction in the AChA territory. We suggest that the existence of the AChA plexal perforators should be recognized to further enhance the safety of hippocampal resection for mTLE.