Conventional Roadmap Research Articles

Retrospective case-control study on radiation dose for uterine artery embolization procedures.

Uterine artery embolization is performed in pre-menopausal women. Understanding the contribution of radiation dose at each stage of the procedure is important for potential dose reduction. The aim was to retrospectively analyse radiation dose on a per-procedural-stage basis, comparing digital subtraction angiography (DSA) and conventional roadmap (CRM). Group A consisted of 50 patients where DSA was used for road mapping at all stages: (I) Aortogram, (II) Left internal iliac artery (IIA) DSA, (III) Left uterine artery (UA) DSA, (IV) Right IIA DSA and (V) Right UA DSA. Group B included 50 patients, where CRM was used for road mapping at stages (II) and (IV). For Group A, mean total dose-area product (DAP) was 39.7 Gy·cm2; mean DAP for each stage were (I) Aortogram = 3.4 Gy·cm2, (II) Left IIA DSA = 5.9 Gy·cm2, (III) Left UA DSA = 3.2 Gy·cm2, (IV) Right IIA DSA = 5.5 Gy·cm2 and (V) Right UA DSA = 3.0 Gy·cm2. For Group B, mean total DAP was 33.6 Gy·cm2, mean DAP for each stage were (I) Aortogram = 3.3 Gy·cm2, (II) Left IIA CRM = 1.5 Gy·cm2, (III) Left UA DSA = 3.3 Gy·cm2, (IV) Right IIA CRM = 1.5 Gy·cm2 and (V) Right UA DSA = 3.3 Gy·cm2. Fluoroscopy time was 10 and 9.4 min for Groups A and B, respectively. The highest road-mapping radiation dose contribution was from bilateral IIA DSA. The use of CRM, intermittent fluoroscopy and elimination of the aortogram is recommended to further reduce procedural radiation dose.

Material-Specific Roadmap Modes Can Improve the Visibility of Liquid Embolic Agents for Endovascular Embolization: A Systematic In Vitro Study.

Endovascular embolization using liquid embolic agents is a safe and effective treatment option for AVMs and fistulas. Because reliable visibility of these liquid embolic agents is essential for intraprocedural visual control to prevent complications, novel angiographic systems are equipped with material-specific roadmap modes. The aim of this study was the systematic in vitro comparison of conventional and material-specific roadmap modes regarding the visibility of the most used liquid embolic agents. A recently introduced in vitro model, resembling cerebral vessels, was embolized with Onyx 18, Squid 18, PHIL 25%, and n-BCA mixed with iodized oil (n = 4 for each liquid embolic agent), as well as with contrast medium and saline, both serving as a reference. Imaging was performed in conventional and material-specific roadmap modes. The visibility of the liquid embolic agents in both modes was compared quantitatively and qualitatively. Significant differences between conventional and material-specific roadmap modes regarding the visibility of the liquid embolic agents were observed for all study groups. All liquid embolic agents were better visible in the material-specific roadmap modes compared with the conventional mode in qualitative and quantitative analyses (eg, Onyx in conventional-versus-material-specific modes along the 1.0-mm sector: mean contrast-to-noise ratio, 5.69 [SD, 0.85] versus 47.18 [SD, 5.72]; P < .001, respectively). In this in vitro study, we demonstrated a better visibility of all investigated liquid embolic agents by using material-specific roadmap modes compared with the conventional roadmap technique. Especially in complex anatomic situations, these novel roadmap modes could improve the visual control and thus the safety and efficacy of embolization procedures in clinical practice.

Identifying predictors of patient radiation dose during uterine artery embolisation.

IntroductionUterine artery embolisation (UAE) is regarded as a safe and effective treatment for symptomatic uterine fibroids and/or adenomyosis. Dose reduction during UAE is critical for this reproductive‐age patient population to minimise the risks of radiation‐induced effects. The aim of this study was to identify the predictors of radiation dose which can be controlled and optimised for patients during UAE.MethodsA total of 150 patients between June 2018 and August 2019 were included in this study. Demographic and clinical information such as age, body mass index (BMI), total number of fibroids, total fibroid volume, total uterus volume and dosimetric measurements on Dose Area Product (DAP), Air Kerma (AK) and fluoroscopy time were recorded. Total digital subtraction angiography (DSA), total conventional roadmap (CRM), total last‐image hold (LIH) and total fluoroscopy were calculated from the dose report. Multiple linear regression analysis was used to identify the independent predictor variables of total dose (DAP) using a regression model.ResultsTotal DSA, total CRM and total LIH were identified as the determinants of dose for UAE (P < 0.05) and together accounted for 95.2% of the variance.ConclusionsThis study identified the key imaging predictors of dose for UAE. Total DSA, total CRM and total LIH were shown to have a greater impact on the outcome DAP compared to other demographic or dosimetric measurements. Optimisation of these predictors during future UAE procedures can facilitate radiation dose reduction to the pelvis and reproductive organs.

Automatic Generation of Road Maps from Low Quality GPS Trajectory Data via Structure Learning

Up-to-date road maps are critical for intelligent transportation applications, such as car navigation and route planning. Unfortunately, conventional road map generation through surveying and image digitizing is labor intensive and time consuming. Nowadays, a large volume of GPS trajectory data can be widely acquired from vehicles mounted GPS receivers. These GPS trajectories are natural data resources for generating up-to-date road maps. Currently, extensive road map generation methods have been developed using the GPS trajectories, however, duo to the noise, low sampling rate, and uneven density distribution of GPS trajectories, most of the state-of-the art methods are not robust enough and usually sensitive to noises. Furthermore, extensive preprocessing and complex refinement steps reduce the power and flexibility of these methods. To produce a more robust and flexible road map generation method from GPS trajectories, a novel method is proposed in this paper. The main innovation part of this paper is that we generate a road map from massive GPS trajectories through principal graph structure learning and tree linking strategy, in this manner, a best-fitting graph structure (principal graph) of GPS points is constructed by optimizing an objective function. Using this method, the influences of noise, low sampling rate, and uneven density distribution can be minimized, which makes the proposed method more robust. The simulated datasets and the real-world GPS trajectory data were used in experimental analysis. The experimental results show the robustness, validity, and strength of the proposed method.

Variable-resolution Velocity Roadmap Generation Considering Safety Constraints for Mobile Robots

This research develops a new roadmap method for autonomous mobile robots based on variable-resolution partitioning of continuous state space. Unlike conventional roadmaps which include position information only, the proposed roadmap also includes velocity information. Each node of the proposed roadmap consists of a fixed position and a range of velocity values, where velocity ranges are determined by variable-resolution partitioning of velocity space. An ordered pair of nodes are connected by a directed link if any combination of velocity values within the ranges represented by the nodes produce a trajectory satisfying a set of safety constraints. In this manner, an executable trajectory connecting arbitrary starting node and destination node is obtained by applying a graph search technique on the proposed roadmap. The proposed method is evaluated through simulations.

Network-oriented road map generation for unknown roads using visual images and GPS-based location information

Car navigation systems (CNS) have become an interesting research and industrial topic due to their wide deployment. However, updating and distribution of the road map database is a complex and high cost process. In this paper, we propose a real-time map generation and updating algorithm, which fulfills or corrects the unknown road area of the conventional road map database by using global positioning system (GPS) information and wireless communication technologies. To generate the road map of unknown roads, the proposed algorithm uses road images, which can be obtained when a driver travels unknown roads. When a driver travels unknown roads, which do not appear on the map of the car navigation system, the car navigation system extracts GPS and image information of the unknown roads. Then, the car navigation system generates the road map for the unknown roads by extracting location and road information, and updates the road map database in the car. After updating the local road map database, the car navigation system updates the master road map database, which is located at the network and is distributed to other car navigation systems. Thus, the road map database provider can update the road map database of other car navigation systems, which share the same master road map database. The proposed algorithm provides an efficient updating process of the road map database with a simplified process and reduced time for unknown road areas.

Abstract No. 227 EE: Feasibility and Usefulness of 3D Roadmap in Vascular Intervention: Clinical Application in Non-Neurological Field

Purpose3D roadmap is a novel technique combining rotational angiography and 2D fluoroscopy, mainly being tried in neurointervention. We applied this technique to non-neurological vascular intervention and evaluated their clinical feasibility and usefulness.Materials and MethodsForty one cases were enrolled, including renal artery angiography (2/41), TACE (22/41), hepatic artery embolization in liver laceration (4/41), uterine artery embolization (5/41), and bronchial artery embolization (8/41). When we conducted the procedures, 3D roadmap was adopted as a choice of imaging guidance tool for microcatheter advancement to target vessels. Clinical feasibility and usefulness were discussed with comparison to conventional roadmap system.Teaching PointsIn 37 procedures, creating 3D roadmap was possible with one time contrast media injection and it was maintained until finishing the procedures. Re-trial was needed in 4 patients due to unwanted patient’s motion and operator’s error. Easier microcatheterization was experienced in 9 TACE, 4 uterine artery embolization and 2 bronchial artery embolization, including easy perception of microvascular anatomy and overcoming image degradation of conventional roadmap image in the patients with poor respiratory control. Application of 3D roadmap to non-neurological vascular intervention is possible. It permits precise and swift approach to the target vessels in the patients with poor respiratory control and complex vascular anatomy. Purpose3D roadmap is a novel technique combining rotational angiography and 2D fluoroscopy, mainly being tried in neurointervention. We applied this technique to non-neurological vascular intervention and evaluated their clinical feasibility and usefulness. 3D roadmap is a novel technique combining rotational angiography and 2D fluoroscopy, mainly being tried in neurointervention. We applied this technique to non-neurological vascular intervention and evaluated their clinical feasibility and usefulness. Materials and MethodsForty one cases were enrolled, including renal artery angiography (2/41), TACE (22/41), hepatic artery embolization in liver laceration (4/41), uterine artery embolization (5/41), and bronchial artery embolization (8/41). When we conducted the procedures, 3D roadmap was adopted as a choice of imaging guidance tool for microcatheter advancement to target vessels. Clinical feasibility and usefulness were discussed with comparison to conventional roadmap system. Forty one cases were enrolled, including renal artery angiography (2/41), TACE (22/41), hepatic artery embolization in liver laceration (4/41), uterine artery embolization (5/41), and bronchial artery embolization (8/41). When we conducted the procedures, 3D roadmap was adopted as a choice of imaging guidance tool for microcatheter advancement to target vessels. Clinical feasibility and usefulness were discussed with comparison to conventional roadmap system. Teaching PointsIn 37 procedures, creating 3D roadmap was possible with one time contrast media injection and it was maintained until finishing the procedures. Re-trial was needed in 4 patients due to unwanted patient’s motion and operator’s error. Easier microcatheterization was experienced in 9 TACE, 4 uterine artery embolization and 2 bronchial artery embolization, including easy perception of microvascular anatomy and overcoming image degradation of conventional roadmap image in the patients with poor respiratory control. Application of 3D roadmap to non-neurological vascular intervention is possible. It permits precise and swift approach to the target vessels in the patients with poor respiratory control and complex vascular anatomy. In 37 procedures, creating 3D roadmap was possible with one time contrast media injection and it was maintained until finishing the procedures. Re-trial was needed in 4 patients due to unwanted patient’s motion and operator’s error. Easier microcatheterization was experienced in 9 TACE, 4 uterine artery embolization and 2 bronchial artery embolization, including easy perception of microvascular anatomy and overcoming image degradation of conventional roadmap image in the patients with poor respiratory control. Application of 3D roadmap to non-neurological vascular intervention is possible. It permits precise and swift approach to the target vessels in the patients with poor respiratory control and complex vascular anatomy.

A roadmap construction algorithm for mobile robot path planning using skeleton maps

Path planning using conventional roadmaps, such as visibility graphs, probability roadmaps and skeleton maps, may have some disadvantages of long length, sharp turns or collisions with obstacles. Specifically, the paths using the conventional skeleton map have unnecessary turns around crossing points, which make longer paths and prevent the robot from moving smoothly. To improve the skeleton map, this paper proposes a new roadmap construction algorithm for path planning of a mobile robot using skeleton maps. The proposed algorithm alleviates the problems of the conventional algorithms by constructing roadmaps which consist of polygons around the crossing points. Simulation results show the efficiency of the proposed algorithm by comparing the results with those obtained using the conventional algorithm.

Comprehending spatial information: The relative efficiency of different methods of presenting information about bus routes.

The study examined the relationship between mode of presentation and ease of comprehension for information about bus routes. The information was presented to subjects in one of the following four ways: (a) as a conventional road map, (b) as a schematic map, (c) as a set of lists of bus stops in sequential order, and (d) as a set of lists of bus stops in alphabetical order. Subjects were given pairs of location names and had to work out which buses were required to get from the first to the second location in each pair. Overall times to solution were faster for the maps than for the lists, with the schematic map being clearly the best form of representation for this task. Complexity (i.e., number of buses required to solve a problem) did not affect performance with the maps but did with the lists, especially the alphabetical lists. (Author)

Testing the Effectiveness of Road Speed Maps and Conventional Road Maps

This paper presents the results of two independent tests undertaken by a broad sample of motorists in the selection of minimum time routes using both the experimental road speed map and the traditional road map as the basic information. The tests are described, the results analysed, and certain conclusions drawn.

Testing the Effectiveness of Road Speed Maps and Conventional Road Maps

This paper presents the results of two independent tests undertaken by a broad sample of motorists in the selection of minimum time routes using both the experimental road speed map and the traditional road map as the basic information. The tests are described, the results analysed, and certain conclusions drawn.

Experimental Maps of Road Travel Speed

Abstract The ideas behind road travel speed maps and the problems involved in designing such maps are described in detail. The author looks forward to the day when such maps might be regarded as 'conventional road maps' enabling the road user to base his choice of route for a particular journey on more information than is currently available.