Effective Imaging Algorithm Research Articles

Safely Reducing Unnecessary Radiographs in Suspected Pediatric Musculoskeletal Injuries: A Multidisciplinary Developed Algorithm.

While radiographs are a critical component of diagnosing musculoskeletal (MSK) injuries, they are associated with radiation exposure, patient discomfort, and financial costs. Our study initiative was to develop a system to diagnose pediatric MSK injuries efficiently while minimizing unnecessary radiographs. This was a quality improvement trial performed prospectively at a single level one trauma center. A multidisciplinary team with leaders from pediatric orthopedics, trauma surgery, emergency medicine, and radiology created an algorithm delineating which x-rays should be obtained for pediatric patients presenting with MSK injuries. The intervention was performed in the following 3 stages: stage 1: retrospective validation of the algorithm, stage 2: implementation of the algorithm, and stage 3: sustainability evaluation. Outcomes measured included number of extra radiographs per pediatric patient and any missed injuries. In stage 1, 295 patients presented to the pediatric emergency department with MSK injuries. A total of 2148 radiographs were obtained, with 801 not indicated per the protocol, for an average of 2.75 unnecessary radiographs per patient. No injuries would have been missed using the protocol. In stage 2, 472 patients had 2393 radiographs with 339 not indicated per protocol, averaging 0.72 unnecessary radiographs per patient, a significant reduction from stage 1 (P < 0.001). There were no missed injuries identified on follow-up. In stage 3, improvement was sustained for the subsequent 8 months with an average of 0.34 unnecessary radiographs per patient (P < 0.05). Sustained reduction of unnecessary radiation to pediatric patients with suspected MSK injuries was accomplished through the development and implementation of a safe and effective imaging algorithm. The multidisciplinary approach, widespread education of pediatric providers, and standardized order sets improved buy-in and is generalizable to other institutions.Level of Evidence: III.

Nonline-of-Sight 3-D Imaging Using Millimeter-Wave Radar

Nonline-of-sight (NLOS) radar imaging is a novel technique that can inverse the scattering characteristics of targets in the NLOS area, which has been one of the hot pots of radar imaging field. However, the existing NLOS radar mainly focuses on 1-D or 2-D imaging, which inevitably suffers from the geometric loss of real 3-D scenes, and its applications are restricted in the urban environment. In this article, we propose an NLOS radar 3-D imaging model and method for looking around corner (LAC) situation by multi-input–multioutput (MIMO) millimeter-wave (mmW) array antennas. In this scheme, first, the model of NLOS radar 3-D imaging with mmW MIMO antennas is established and the multipath scattering of targets with this model is analyzed. Then, the theoretical resolution of LAC 3-D imaging is derived and discussed. Second, exploiting the three bounces of LAC and extraction of linear structure, an effective imaging algorithm with mirror projection theory and Radon transform, dubbed as mirror symmetry backprojection (MSBP), is proposed for 3-D image focusing. Moreover, to suppress the uncertainties of phase caused by both LAC and system error, the minimum entropy principle is introduced to MSBP. Finally, an NLOS 3-D imaging system with 77-GHz mmW MIMO radio frequency module and 2-D rails is developed. Different types of targets, such as metal balls and ornaments, are tested in LAC. The results demonstrate that our NLOS technique can not only provide a high-quality 3-D focusing of the hidden targets but also extract positions of targets without prior knowledge of the NLOS area.

Advanced high-order nonlinear chirp scaling algorithm for high-resolution wide-swath spaceborne SAR

Spaceborne Synthetic Aperture Radar (SAR) is a well-established and powerful imaging technology that can provide high-resolution images of the Earth’s surface on a global scale. For future SAR systems, one of the key capabilities is to acquire images with both high-resolution and wide-swath. In parallel to the evolution of SAR sensors, more precise range models, and effective imaging algorithms are required. Due to the significant azimuth-variance of the echo signal in High-Resolution Wide-Swath (HRWS) SAR, two challenges have been faced in conventional imaging algorithms. The first challenge is constructing a precise range model of the whole scene and the second one is to develop an effective imaging algorithm since existing ones fail to process high-resolution and wide azimuth swath SAR data effectively. In this paper, an Advanced High-order Nonlinear Chirp Scaling (A-HNLCS) algorithm for HRWS SAR is proposed. First, a novel Second-Order Equivalent Squint Range Model (SOESRM) is developed to describe the range history of the whole scene, by introducing a quadratic curve to fit the deviation of the azimuth FM rate. Second, a corresponding algorithm is derived, where the azimuth-variance of the echo signal is solved by azimuth equalizing processing and accurate focusing is achieved through a high-order nonlinear chirp scaling algorithm. As a result, the whole scene can be accurately focused through one single imaging processing. Simulations are provided to validate the proposed range model and imaging algorithm.

PEDIATRIC ORTHOPEDIC RADIOGRAPH REDUCTION: A QUALITY IMPROVEMENT INITIATIVE

Background:Children are more vulnerable to ionizing radiation which increases health risks later in life including cancer. An interdepartmental team developed an algorithm to guide providers ordering extremity radiographs in pediatric patients with musculoskeletal (MSK) injuries.Purpose:Reduce unnecessary pediatric radiation/extremity radiographs through development and implementation of an interdepartmental designed algorithm. Determine utility, safety, and efficacy of the algorithm through retrospective and prospective analysis.Methods:Our study was performed at an academic pediatric trauma center. An interdepartmental committee including pediatric orthopedic surgery, emergency medicine, trauma, and radiology providers created a MSK injury imaging algorithm (Figure 1). We retrospectively validated the algorithm for efficacy and safety through chart review of pediatric patients seen in the ED with MSK extremity injury, identified through CPT code, from 6/24/2016 through 8/31/2016. We determined the number of extra radiographs per patient and identified if injuries would be missed utilizing our protocol. After retrospective validation, guideline implementation was undertaken through multidisciplinary education. The imaging guideline was prospectively implemented in the pediatric ED from 6/24/2018 through 8/31/2018. We continued to prospectively evaluate through selecting one week every month over the following eight months to determine sustainability of the implemented algorithm.Results:Our interdepartmental team in 2016 developed a pediatric MSK radiograph protocol (Figure 1). A retrospective chart and radiograph review of 295 pediatric patients between 6/24/2016 through 8/31/2016 was analyzed correlating physical examination to appropriate radiographs. Utilizing the protocol, the review revealed an average of 2.75 extra radiographs per patient. No injuries were missed. Providers including orthopedic and emergency medicine attendings, mid-levels, and residents were educated through meetings, emails, and having the protocol posted and easily accessible. Our protocol was implemented 6/24/18 and underwent prospective enrollment and review through 8/31/18 which revealed a reduction to 0.72 radiographs per patient (P-value <0.001) (Figure 2). Eight month follow up revealed a sustainable reduction in extra radiographs per patient (Figure 3).Conclusion:Reduction of unnecessary radiation to pediatric patients with MSK extremity injuries was accomplished through development and implementation of a safe and effective imaging algorithm. The multidisciplinary approach combined with widespread education of pediatric providers improved buy-in driving a sustainable system improvement.Figure 1.Pediatric Extremity Injury AlgorithmFigure 2.Average number of radiographs per pediatric patient not indicated by imaging algorithms before and after protocol implementation. (P<0.001)Figure 3.Eight month follow up of average number of extra radiographs per patient

ESPR Uroradiology Taskforce--imaging recommendations in paediatric uroradiology, part VIII: retrograde urethrography, imaging disorder of sexual development and imaging childhood testicular torsion.

Three new consensus-based recommendations of the European Society of Paediatric Radiology Uroradiology Taskforce and the European Society of Urogenital Radiology Paediatric Working Group on paediatric uroradiology are presented. One deals with indications and technique for retrograde urethrography, one with imaging in the work-up for disorders of sexual development and one with imaging workflow in suspected testicular torsion. The latter is subdivided to suggest a distinct algorithm to deal with testicular torsion in neonates. These proposals aim to outline effective imaging algorithms to optimise diagnostic accuracy and to harmonize diagnostic imaging among institutions and practitioners.

ESPR uroradiology task force and ESUR paediatric working group: imaging recommendations in paediatric uroradiology, part IV

Two new recommendations of the European Society of Radiology task force and the European Society of Uroradiology workgroup on paediatric uroradiology are presented. One deals with diagnostic imaging in children after trauma to the urinary tract-renal trauma, in particular. The other concerns the evaluation of suspected renal hypertension. Available data in the paediatric literature are either unsatisfactory or controversial for both of these clinical settings. Therefore, the following consensus-based proposals aim at outlining effective imaging algorithms to reduce invasive imaging procedures while optimising diagnostic accuracy. The objective of following a more uniform imaging approach is to facilitate future meta-analysis as well as multicentre and other more evidence-based studies. The practise in paediatric radiology is typically based on local availability and on the limitations of professional expertise and equipment, balanced against the perceived needs of the individual child. Although this is unlikely to change in the near future, it does not release the physicians in charge of diagnostic imaging from their responsibility in choosing and providing state-of-the-art imaging and management protocols that are adapted specifically for use in children.

Side-looking echo data transform to squint mode SAR imaging

Nowadays the side-looking SAR echo data can be obtained easily from the commercial channel, while that of other SAR imaging modes such as squint, spotlight are difficult to be acquired. This paper presents a new scheme to transform the side-looking returns to squint ones, in a direct and an indirect approach respectively. Direct transformation uses the data with a wide azimuth beam angle. The maximum of the required squint angle is limited under several degrees. Squint data under indirect transformation can be obtained by adding a platform velocity along slant range according to the required squint angles. Then the squint data is determined by the angle between the new forward velocity and line-of-sight direction. This method results in higher squint angle compared with the first one. Verification shows the feasibility of these approaches with illustration of side-looking E-SAR raw data processing. The future work will be on the precise Doppler centroid estimation and effective imaging algorithm development.