Rotational Angiography Research Articles

Agreement and reproducibility between 3DStent vs. Optical Coherence Tomography for evaluation of stent area and diameter

Abstract3DStent is a novel rotational angiography imaging capable of 3D reconstruction and measuring stent area and diameter, without need for intravascular imaging. To compare 3DStent and OCT-derived stent area and diameter after PCI. Patients with de novo coronary lesions who underwent treatment with a single DES and evaluated by OCT and 3DStent were included. Stent area and diameter were measured by 3DStent, at abluminal, mid and endoluminal side and by OCT. From September 2023 to February 2024 six coronary lesions were analyzed. Post-PCI stent area measured by OCT was (mean ± standard deviation) 7.03 ± 2.85 mm2 and by 3DStent 9.41 ± 2.79 mm2, 7.21 ± 2.23 mm2 and 5.63 ± 1.83 mm2 at abluminal, mid and endoluminal side, respectively. Stent diameter by OCT was 2.93 ± 0.58 mm, and by 3DStent 3.27 ± 0.50 mm, 2.86 ± 0.49 mm and 2.52 ± 0.45 mm at abluminal, mid and endoluminal side, respectively. Significant correlation was observed between OCT and 3DStent in relation to stent area (Exp(B) 3.35, mean of difference 0.19 ± 1.01 mm2, 95%CI -1.80–2.17 mm2, p < 0.001) and diameter (Exp(B) 3.18, mean difference − 0.07 ± 0.18 mm, 95%CI -0.43–0.30 mm, p < 0.001), particularly when 3DStent measurements performed at the mid side. Very high reproducibility was demonstrated by intra- and inter-observer analysis (r = 0.92 and r = 0.93 respectively). 3DStent appears to be an easy and reproducible tool to assess post-PCI stent area and diameter as compared to OCT.

Atrial fibrillation recurrence rates in patients with transthyretin cardiac amyloidosis undergoing pulmonary vein isolation: a comparative retrospective study with propensity score matching

Abstract Background Atrial fibrillation (AF) affects up to 70% of individuals diagnosed with transthyretin cardiac amyloidosis (ATTR CA) [1]. AF ablation is frequently considered in the management of these patients, but there is a lack of data about outcomes of the procedure in this population. Purpose This study aims to evaluate AF recurrence rates and long-term AF recurrence-free survival in patients with ATTR CA undergoing pulmonary vein isolation (PVI). Methods A single-center retrospective study was conducted, including all patients diagnosed with ATTR CA who underwent PVI from 2016 to 2023. We compared patients with amyloidosis (cases) to those without (controls), employing propensity score matching for age, gender, AF type (paroxysmal vs. persistent), BMI, diabetes, arterial hypertension diagnosis, antiarrhythmic drug therapy post-index ablation, and left atrium (LA) volume assessed by 3D rotational angiography (3DRA). Results 16 patients with CA were matched to 16 patients without (32 patients in total). After matching, the populations demonstrated comparable baseline characteristics (figure 1). The study consistently revealed a higher AF recurrence rate, after PVI, in the CA group (81.3%) compared to the control group (37.5%) at the last follow-up (p-value 0.01) (median follow-up 1255 ± 1055 days in CA and 1491 ± 464 days in control group), as well as a significantly lower long-term AF-recurrence free survival (log-rank p = 0.01 – figure 2). Additionally, the recurrence rate at 1-year post-procedure was 56.25% in the CA group and 18.75% in the control group (p-value 0.03). Conclusions Pulmonary vein isolation remains a viable treatment option for individuals with ATTR CA. However, it proved less effective (or less durable) than in the general population without the disease, both at 1-year follow-up and for longer periods, as shown also with recurrence-free survival rate. Further studies are warranted to determine the optimal treatment strategy for this specific population.Baseline Characteristics fig. 1Kaplan Meyer fig. 2

Transarterial embolization for anterior cranial fossa dural arteriovenous fistula based on multi-modal three-dimensional imaging

Background: Dural arteriovenous fistula (DAVF) in the anterior cranial fossa (ACF) is known to show a high risk of intracranial hemorrhage. Recently, multi-modal fusion imaging with computed tomography angiography, computed tomography venography, and three-dimensional (3D) rotation angiography have been used preoperatively to ensure anatomical safety. We report on endovascular treatment as a first-line approach for ACFDAVF based on the understanding of vascular anatomy obtained from multi-modal fusion imaging. Methods: All patients with ACF-DAVF treated endovascularly as a first-line approach were included in this study. Analyses took into account complications (particularly visual function), immediate angiographic outcomes, and follow-up findings in consecutive patients with ACF-DAVF treated with interventional treatment based on multi-modal fusion imaging. Results: Five patients with ACF-DAVF underwent six sessions of transarterial embolization (TAE) in our institution. The five male patients (mean age, 74.5 years; range, 60–84 years) were treated with liquid embolic agents (Onyx, four procedures; n-butyl 2-cyanoacrylate, two procedures). No difference was seen between preoperative image evaluation and image evaluation during the endovascular procedure, and in all cases, a microcatheter was navigated into a target artery assumed from preoperative multi-modal imaging, allowing treatment completion in a single procedure. In all cases, the shunt disappeared completely and visual function after procedure was maintained. At the last follow-up, all patients showed a modified Rankin scale score of 0 or 1 with no recurrences. Conclusion: Multi-modal fusion imaging facilitates a 3D understanding of the vascular anatomy, allowing TAE as the first-line treatment for ACF-DAVF.

A review of intracranial aneurysm imaging modalities, from CT to state-of-the-art MR.

Traditional guidance for intracranial aneurysm (IA) management is dichotomized by rupture status. Fundamental to ruptured aneurysm management is the detection and treatment of subarachnoid hemorrhage, along with securing the aneurysm by the safest technique. On the other hand, unruptured aneurysms first require a careful assessment of natural history versus treatment risk, including an imaging assessment of aneurysm size, location, and morphology, along with additional evidence-based risk factors such as smoking, hypertension, and family history. Unfortunately, a large proportion of ruptured aneurysms are in the lower risk size category (<7mm), putting a premium on discovering a more refined non-invasive biomarker to detect and stratify aneurysm instability prior to rupture. In this review of aneurysm work-up, we cover the gamut of established imaging modalities (e.g., CT, CTA, DSA, FLAIR, 3D-TOF-MRA, CE-MRA) as well as more novel MR techniques (MR-VWI, DCE-MRI, CFD). Additionally, we evaluate the current landscape of AI software and their integration into diagnostic and risk stratification pipelines for IAs. These advanced MR techniques, increasingly complemented with AI models, offer a paradigm shift by evaluating factors beyond size and morphology, including vessel wall inflammation, permeability, and hemodynamics. Additionally, we provide our institution's scan parameters for many of these modalities as reference. Ultimately, this review provides an organized, up-to-date summary on the array of available modalities/sequences for IA imaging to help build protocols focused on IA characterization.ABBREVIATIONS: IA = intracranial aneurysm; LP = lumbar puncture; UIA = unruptured intracranial aneurysm; VWI = vessel wall imaging; 3DRA = 3D Rotational Angiography.

Intraoperative contrast-enhanced cone beam CT allows visualization of the ‘dark side’ of the clot and improves mechanical thrombectomy performance

BackgroundVisualization of the clot is key to the endovascular treatment of ischemic stroke, but identification of the distal part of the clot and distal arteries during mechanical thrombectomy (MT) remains...

Novel visually guided leadless pacemaker implantation using the latest high-speed intraprocedural 3-dimensional rotational angiography system

Novel visually guided leadless pacemaker implantation using the latest high-speed intraprocedural 3-dimensional rotational angiography system

Geometry of Terminal Internal Carotid Artery Bifurcation May Be Associated With Middle Cerebral Artery Plaque Ulceration: A Three-Dimensional Rotational Angiography Study.

Geometry of Terminal Internal Carotid Artery Bifurcation May Be Associated With Middle Cerebral Artery Plaque Ulceration: A Three-Dimensional Rotational Angiography Study.

Percutaneous pulmonary valve implantation guided by three-dimensional rotational angiography

Percutaneous pulmonary valve implantation guided by three-dimensional rotational angiography

Evaluation of micro-remnant niduses of arteriovenous malformations post-gamma knife radiosurgery by 3D-rotational angiography.

Recent innovations in radiological imaging have enabled the detection of micro-remnant niduses of arteriovenous malformations (AVMs) after gamma knife radiosurgery (GKS), which have not been previously perceptible. Herein, we focus on the difficulty of evaluating micro-remnant AVMs after GKS that are hardly perceptible on conventional examinations and propose integrating follow-up three-dimensional rotational angiography (3D-RA) in the previous gamma plan as a solution. We retrospectively searched NTT Medical Center Tokyo hospital database for patients with AVMs who underwent both two-dimensional digital subtraction angiography (2D-DSA) and 3D-RA as follow-up for GKS from February 2021 to January 2024. Patients with suspected nidus occlusion on the latest non-contrast-enhanced magnetic resonance angiography (NC-MRA) were included, and contrast-enhanced magnetic resonance angiography (CE-MRA), 2D-DSA, and 3D-RA were evaluated. Twelve patients with 13 AVM sites were defined as having complete nidus occlusion on upfront NC-MRA. On 2D-DSA, seven AVM sites showed the presence of slight remaining AVMs based on the detection of remnant drainage veins, however the nidus was not detected in three cases. Nevertheless, 3D-RA detected micro-remnant niduses in all seven AVM sites, and four patients underwent re-GKS. Nine patients with ten AVM sites also underwent CE-MRA, and six AVM sites were diagnosed with radiation-induced parenchymal injury. Importing the 3D-RA image into the treatment planning has the potential to be more helpful than NC-MRA or CE-MRA to detect micro-remnant AVMs and evaluate the true remnant volume, and may contribute to a more detailed treatment planning, thereby improving the results of GKS retreatment.

Dual Volume Image Fusion Technique for Anatomical Evaluation of Cavernous Sinus Dural Arteriovenous Fistula: Usefulness for Transvenous Target Segment Embolization

In this preliminary study, we investigated the value of fusion techniques by flat detector computed tomography based dual volume rotational angiography (DVRA) for the evaluation of the anatomical relationship of cavernous sinus dural arteriovenous fistula (CSDAVF) and assessed the possibility of transvenous target segment embolization. Twenty-six patients with CSDAVF supplied by multiple feeders underwent DVRA for each feeding large vessel separately. We assessed the anatomical relationship of feeders, fistula points, and venous drainage with three dual volume image fusion techniques. Transvenous embolization was targeted to the segment of fistulous point for preserving those not involved and reducing coil mass effect. Dual vessel multi-planar reconstruction fusion technique could show which segment of the cavernous sinus supplied by feeding arteries. In the dual vessel volume rendering fusion technique, the association between feeding arteries, fistula points, and draining veins of 2 different vessels could be accurately identified in 3 dimensions. In addition, we could visualize the exact anatomical relationship between the components of CSDAVF and skull anatomy with the single vessel fusion technique. Based on various fusion images, target segment embolization was successfully performed in 8 patients. In this group, we achieved complete or near complete occlusion without complications, including cranial nerve palsy. Detailed anatomical information including accurate fistula point, specific feeding arteries, and draining veins could be obtained with various dual volume image fusion techniques. In addition, the target segment embolization of CSDAVF could be possible with understanding of the precise CSDAVF architectures.

Quantitative and qualitative assessment of left atrial cardiomyopathy as well as prediction of atrial fibrillation recurrences upon PVI using machine learning

Abstract Introduction Atrial fibrillation (AF) is one of the most common heart pathologies in daily clinical practice and confers significant mortality and morbidity. However, AF ablation often proves ineffective - even after successful pulmonary vein isolation (PVI). The prediction of PVI failure for the long-term treatment of AF as well as the improved assessment of the underlying substrate appears pivotal. We hypothesize, that ML can be applied to better characterize the substrate and recurrence in AF patients upon PVI. Methods &amp; Results We retrospectively evaluated data from 205 patients that underwent AF ablation between 2019 and 2023, including high-density 3D electroanatomic maps (sinus rhythm), LA rotational angiography, invasive LA hemodynamic measurements (after transseptal passage), echocardiography, 12-lead ECG and laboratory testing. A neuronal net was trained on selected features extracted from those datasets using supervised learning and employed to predict measures of atrial cardiomyopathy and AF recurrence. Patients were 66±1 years old and received first or second pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation with 18% documented recurrences upon a mean follow-up of 23±1months. First, we extensively refined or developed tools for automated P-wave analysis from 12-lead ECGs as well as local LA voltage and volume quantification. Next, LA hemodynamics and volumes were assessed: Mean LA volume as derived from rotational angiography significantly correlated with LA volume index as obtained using echocardiography. Interestingly, LA size showed no correlation with NT-proBNP, LA low voltage or LA hemodynamics. In addition, global (25±2% of total LA area) and local (i.e. anterior, posterior, roof) LA voltage was determined and shown to be an independent predictor of AF recurrence. In our first unselected subset of 136 patients with 2nd PVI for atrial fibrillation, our ML models predicted LA fibrosis (i.e. low voltage regions; Utah stage) from 12-lead ECGs with an accuracy of 90%. Accuracy was 87% for the prediction of AF recurrences from LA pressure and low-voltage regions. In addition, the algorithm predicted AF recurrences from 12-lead SR ECGs obtained before PVI with an accuracy of 91%. Conclusion Artificial neural networks allow to quantitatively and qualitatively predict measures of atrial cardiomyopathy and atrial fibrillation recurrence probability upon complete PVI with high accuracy.Figures

Intra-procedural three-dimensional rotational angiography in cryoballoon ablation of atrial fibrillation - results from a randomised clinical trial

Abstract Introduction There are a variety of approaches for pre-procedural imaging to facilitate atrial fibrillation (AF) ablation. Intra-procedural three-dimensional rotational angiography (3DRA) is the least employed method and it can be advantageous regarding efficiency and procedural logistics (1). There is an open question whether LA imaging could improve safety and outcomes of cryoballoon (CB) ablation. Purpose The aim of this study is to evaluate possible benefits of 3DRA for procedural success, safety and long-term outcomes of CB ablation. Methods We designed a single-centre unblinded randomised clinical trial and recruited 134 patients (64.2% male, 59.0±11.6 years) with paroxysmal (93.3%) and early-persistent AF. Patients were randomised to no imaging or 3DRA which was performed intra-procedurally after trans-septal puncture. Angiographic images were segmented and overlaid to the fluoroscopy screen to guide the ablation procedure. Patients were scheduled for follow-up visits and twenty-four hour ECG recordings at 3, 6 and 12 months, and every 6 months thereafter. Results Of all the patients recruited, 66 (49.3%) were randomised to 3DRA and angiography was successfully performed in all but one patient (1.5%). Procedure time was significantly longer when 3DRA was performed (86.7±27.8 min compared to 67.2±22.1 in non-3DRA group, p&amp;lt;0.001). Total radiation dose (447.4±485.0 vs. 133.9±166.2 mGy, p&amp;lt;0.001) and contrast administration (131.8±28.3 vs. 40.8±26.5 ml, p&amp;lt;0.001) were significantly higher in the 3DRA group (Table 1). In patients who received no imaging one pulmonary vein (PV) couldn’t be isolated in 2 patients while this occurred in 3 patients in the 3DRA group (OR 1.57, 95% CI 0.25-9.72). Only minor complications were reported in both groups. Five patients developed large haematoma (4 in the 3DRA group vs. 1 in the control group). In each group there were 3 incidents of impending or transient phrenic nerve palsy. During 12 months of follow-up, 88.2% of patients in the control group and 81.8% in the 3DRA group were free of atrial fibrillation (OR 1.67, 95% CI 0.63-4.38). Two patients from the control group developed atrial flutter and were treated by ablation. In total, 10 patients underwent redo procedures (7 in the control and 3 in the 3DRA group respectively) and PV reconnections were detected in 9 cases. Conclusion 3DRA is a safe and efficient intra-procedural imaging method to guide CB ablation of AF. However, it significantly increases procedure duration, total radiation dose and contrast expenditure. In our trial it did not have any impact on the acute success rate of PV isolation or freedom from atrial fibrillation during 12-month follow-up.

High variability in physician estimations of flow-diverting stent deployment versus PreSize Neurovascular software simulation: a comparison study

BackgroundPhysician variablity in preoperative planning of endovascular implant deployment and associated inaccuracies have not been documented. This study aimed to quantify the variability in accuracy of physician flow diverter (FD)...

Three-dimensional Images Fusion Method Useful for Preoperative Simulation of Clipping Surgery for Cerebral Aneurysms.

This study aimed to introduce a three-dimensional (3D) images fusion method for preoperative simulation of aneurysm clipping. Consecutive unruptured aneurysm cases treated with surgical clipping from March 2021 to October 2023 were included. In all cases, preoperative images of plain computed tomography (CT), CT angiography, magnetic resonance imaging (MRI) 3D fluid-attenuated inversion recovery, 3D heavily T2-weighted images, and 3D rotational angiography were acquired and transported into a commercial software (Ziostation2 Plus, Ziosoft, Inc. Tokyo, Japan). The software provided 3D images of skull, arteries including aneurysms, veins, and brain tissue that were freely rotated, magnified, trimmed, and superimposed. Using the 3D images fusion method, two operators predicted clips to be used in the following surgery. The predicted clips and actually used ones were compared to give agreement scores for the following factors: (1) type of clips (simple or fenestrated), (2) shape of clips (straight, curved, angled, or bayonet), and (3) clipping strategy (single or multiple). The agreement score ranged from 0 to 3 because a score of 1 or 0 was given for agreement or disagreement on each factor. Interoperator reproducibility was also evaluated. During the study period, 44 aneurysms from 37 patients were clipped. All procedures were successfully completed, thanks to the precisely reproduced surgical corridors with the 3D images fusion method. Agreement in clip prediction was good with mean agreement score of 2.4. Interobserver reproducibility was also high with the kappa value of 0.79. The 3D images fusion method was useful for preoperative simulation of aneurysm clipping.

Use of rotational angiography with 3D reconstruction as a guide for stent aortoplasty in a pediatric patient with coarctation of the aorta

Use of rotational angiography with 3D reconstruction as a guide for stent aortoplasty in a pediatric patient with coarctation of the aorta

Anterior Choroidal Artery Aneurysm Clipping: Angiographic Diagnostics and Surgical Tactics Focused on Visualizing the Anterior Choroidal Artery Behind the Aneurysm

This study describes our experiences with AChA aneurysm clipping with a focus on visualizing the anterior choroidal artery (AChA) just behind the aneurysm to identify the risk factors for adhesion of the AChA or its branches to the posterior wall of the AChA aneurysm. The initial segment of the AChA just behind the aneurysm was evaluated preoperatively using 3D rotational angiography and its course was designated as posteromedial, posterior, or posterolateral. The posterior aspect of the AChA aneurysm was inspected intraoperatively using an endoscope or micromirror. Based on 3D rotational angiography, the main trunk of the AChA showed a posteromedial (n = 47, 57.3%), posterior (n = 18, 22.0%), or posterolateral (n = 17, 20.7%) course just behind the aneurysm. Intraoperatively, 14.6% (12 of 82) of the clipped AChA aneurysms revealed an AChA branch adhered to the posterior wall of the aneurysm. A multivariate analysis revealed that the posterior or posterolateral course of the initial segment of the AChA was a statistically significant risk factor for adhesion of an AChA branch to the posterior wall of the aneurysm (OR 21.083, 95% CI 2.567-173.166, p = 0.005). The initial course of the AChA just behind an AChA aneurysm can be evaluated using 3D rotational angiography. In contrast to a posteromedial course, a posterior or posterolateral course of the AChA just behind an AChA aneurysm can be a significant risk factor for adhesion of an AChA branch to the posterior wall of an AChA aneurysm.

Quantitative evaluation of the effects of flow diverter treatment on aneurysm hemodynamics using time-resolved rotational angiography.

There have been immense advancements in the hardware and software of digital subtraction angiography systems over the last several years. These advancements continue to make progress toward the goals of offering better visualization and reducing radiation exposure. A newer advancement in this arena is presenting three-dimension data over time resulting in four-dimensional-digital subtracted angiography visualization. We have evaluated these protocols related to the evaluation of the treatment of intracranial aneurysms with pipeline flow diversion. Four-dimensional-digital subtracted angiography imaging was acquired on an Artis Q Biplane angiographic system (Siemens Healthcare AG, Forchheim, Germany). A six second four-dimensional-digital subtracted angiography protocol was performed pre and post flow diverter placement. Pre and post reconstructed images were sent through a dedicated prototype research workstation (Syngo X-Workplace; Siemens Healthineers AG) for further flow evaluation. The treatment of an aneurysm with flow diversion led to a filling delay of 0.278 ± 0.422 s inside the aneurysms, whereas distal to the aneurysms the filling of the vessel segment occurred earlier post procedural (negative filling delay of -0.15 ± 0.31 s. The flow ratio inside the aneurysm decreased to 63.6 ± 23% of its pre-treatment value and distal to the aneurysm the flow remained substantially the same (flow ratio: 95.6 ± 0.29%). Data showed a relative filling delay of the aneurysm normalized to the distal vessel of 0.43 ± 0.36 s. The relative flow ratio of the aneurysm in comparison to the distal parent vessel was 72.2 ± 31%. Analysis of a four-dimensional-digital subtracted angiography acquisition allows assessment of the effects of flow diversion treatment on aneurysm hemodynamic parameters and shows a significant decrease in flow inside the aneurysm compared to the parent vessel distal to the aneurysm.

Three-Dimensional Rotational Angiography as Guidance for Percutaneous Patent Ductus Arteriosus (PDA) Device Closure: A Case Report

Background: Patent Ductus Arteriosus (PDA) is a prevalent congenital heart defect characterized by the persistence of an open arterial connection between the aorta and the pulmonary. Percutaneous PDA closure involves deploying occlusion devices through catheter- based procedures. Case Presentation: We report a 1-year and 6-month-old girl diagnosed with Patent Ductus Arteriosus, presented with persistent complaints of failed to thrive , shortness of breath and recurrent cough. Physical examination revealed a continuous murmur at the upper left sternal border, and the Echocardiography examination confirmed a PDA with size of 4-7 mm, with diastolic shortening and dilatation of the Main Pulmonary Artery (MPA). The successful percutaneous PDA device closure procedure was performed using Three-Dimensional Rotational Angiography (3DRA), following an attempt with Two-Dimensional Angiography, which failed to determine the actual defect size in the patient. Conclusions: Confirming the morphology and size of a PDA can be difficult due to its location between the aorta and pulmonary blood vessels, making it a challenging congenital anomaly to assess accurately. 3DRA precisely delineates the PDA structure located between the aortic and pulmonary blood vessels and acts as a guidance tool for percutaneous PDA device closure.

Preoperative Angiographic Protocol for the Surgical Management of Spinal Dural Arteriovenous Fistulas: A Technical Nuance for Safe Minimally Invasive Surgery

BackgroundInterruption of the fistoulus point is the goal of the treatment of spinal dural arteriovenous fistula (dAVFs). Microsurgery still represents a highly efficient treatment in terms of complete occlusion with the lowest risk of recurrence rate. It is reported that the hardest step consists in finding the fistulous site itself, potentially extending surgical access and time, and increasing potential post-operative surgical-related complications. The accurate preoperative detection of the shunt and spinal level together is crucial for guiding optimal, fast and safe microsurgical treatment. MethodsIn the present paper, the authors describe a preoperative angiographic protocol for achieving a safe and simple resection of spinal dAVFs based on a six-year Institutional experience of forty-two patients who underwent minimally invasive. Two illustrative cases are also included in order to support the technical descriptions. ResultsThe suspected artery associated to the vascular malformation of interest is studied in our angiographic protocol through non-subtracted selective acquisitions in the lateral projection. The resulting frames are reconstructed with 3D Rotational Angiography. The implementation of the preoperative angiographic protocol allowed 100% of intraoperative identification of the fistoulus point in all cases with the use of minimally invasive approach. ConclusionsNowadays, neurosurgeons advocate for minimally invasive procedures and low morbidity risk procedures for the treatment of spinal dAVFs.Our preoperative approach for accurate angigoraphic localization of the fistoulus point through non-subtracted and 3D reconstructed angiography allowed to achieve safe and definitive occlusion of the shunt.

Weighted CTDI Equation for 3D Rotational Angiography: A Monte Carlo Study

This study aims to verify the weighted Computed Tomography Dose Index (CTDIw) coefficients of 3D rotational angiography (3DRA) procedure using Monte Carlo simulation. The Monte Carlo simulation EGSnrc usercode was employed for 3D dose simulations of the rotational angiography procedure. A virtual phantom resembles the head CTDI phantom was constructed, with a diameter of 16 cm and a density resembling polymethyl methacrylate (1.13 g/cm3). A series of virtual phantoms consisting of 5 images with ionization chamber detectors at the center position, 12 o'clock, 9 o'clock, 6 o'clock, and 3 o'clock were acquired. Simulations were performed with photon sources of 70 and 109 kVp for 200-degree x-ray tube rotation. The field of view was divided into narrow, wide, and full beam with diameters of 1.7 cm; 4.9 cm; and 8.6 cm, respectively. The simulated doses at the ionization chamber were processed into weighting factor for weighted CTDI and compared with direct measurements. The dose ratio between peripheral and center positions for 360° CBCT and 200° 3DRA was 1:1 and 1:3 in this study. The weighting factors for 3DRA were determined as CTDIcenter = ¼ and CTDIperiphery = ¾. The measured average percentage difference of CTDIw between our weighted factor and conventional CTDIw was 1.75 % (-3.99 % to 6.08 %). The x-ray tube position of 3DRA impacted the accuracy of weighting factor of CTDIw, with implications for the proposed weighting factor (Wcenter = ¼ and Wperiphery = ¾) when using a 3DRA machine.