Optimal Image Quality Research Articles

Unmanned aerial vehicles for human detection and recognition using neural-network model.

Recognizing human actions is crucial for allowing machines to understand and recognize human behavior, with applications spanning video based surveillance systems, human-robot collaboration, sports analysis systems, and entertainment. The immense diversity in human movement and appearance poses a significant challenge in this field, especially when dealing with drone-recorded (RGB) videos. Factors such as dynamic backgrounds, motion blur, occlusions, varying video capture angles, and exposure issues greatly complicate recognition tasks. In this study, we suggest a method that addresses these challenges in RGB videos captured by drones. Our approach begins by segmenting the video into individual frames, followed by preprocessing steps applied to these RGB frames. The preprocessing aims to reduce computational costs, optimize image quality, and enhance foreground objects while removing the background. This results in improved visibility of foreground objects while eliminating background noise. Next, we employ the YOLOv9 detection algorithm to identify human bodies within the images. From the grayscale silhouette, we extract the human skeleton and identify 15 important locations, such as the head, neck, shoulders (left and right), elbows, wrists, hips, knees, ankles, and hips (left and right), and belly button. By using all these points, we extract specific positions, angular and distance relationships between them, as well as 3D point clouds and fiducial points. Subsequently, we optimize this data using the kernel discriminant analysis (KDA) optimizer, followed by classification using a deep neural network (CNN). To validate our system, we conducted experiments on three benchmark datasets: UAV-Human, UCF, and Drone-Action. On these datasets, our suggested model produced corresponding action recognition accuracies of 0.68, 0.75, and 0.83.

Automatic patient centering in computed tomography: a systematic review and meta-analysis.

To comprehensively examine the influence of auto-patient centering technologies on positioning accuracy, radiation dose, image quality, and time efficiency of computed tomography (CT) scans. A systematic search of peer-reviewed English publications was performed between January 2000 and November 2023 in PubMed, Embase, CINAHL, Scopus, and Web of Science. Two postgraduate students and an academic lecturer independently reviewed the articles to verify adherence to the inclusion criteria. The QUADAS-2 tool was employed to evaluate study quality. We derived summary estimates on positioning accuracy, radiation dose reduction, image quality, and time efficiency using proportion and meta-analysis methodologies. Nine studies were identified comparing automatic and manual CT positioning. Automatic positioning improved accuracy by reducing vertical offsets to 7 mm and 4 mm for thorax and abdominal CTs, compared to 19 mm and 18 mm with manual methods. Most studies showed significant reductions in radiation dose, ranging from 5.71 to 31%. Image quality results were mixed, automatic methods generally produced images with less noise, but differences were minimal. Time efficiency was better, with automatic positioning reducing preparation time from 0.48 min versus 0.67 min for manual positioning. This review confirms that automatic patient-centering technologies enhance positioning accuracy and decrease preparation times in CT scans. While reductions in radiation doses and some improvements in image quality were observed, the evidence remains mixed. Findings support integrating these technologies into clinical practice to optimize patient care. Question Does automatic patient centering in CT enhance positioning accuracy, reduce radiation exposure, and improve image quality? Findings Findings indicate that automatic centering can optimize image quality, reduce examination times and contribute to overall improvements in imaging efficiency. Clinical relevance Automatic patient centering in CT improves positioning accuracy, minimizes radiation exposure, enhances image quality, and accelerates imaging workflows, contributing to safer, more efficient imaging procedures that benefit patient care.

OPTIMIZATION OF EXPOSURE FACTORS WITH VARIATION OF FILTER THICKNESS ON DOSE VALUES AND RADIOGRAPHIC IMAGE QUALITY IN PELVIS EXAMINATION

This study examines the impact of varying X-ray tube voltage (kV) and filter thickness on patient radiation dose and image quality in radiographic procedures. It aims to optimize exposure factors to minimize patient dose while maintaining diagnostic image quality, contributing to safer and more efficient radiological practices. This quantitative experimental study investigates the impact of varying filter thickness and tube voltage on patient radiation dose. Using X-ray equipment, dosimeters, and phantoms, measurements of Incident Air Kerma (INAK) and Entrance Surface Air Kerma (ESAK) and effective dose are taken, followed by image quality assessments to optimize exposure factors while maintaining diagnostic efficacy. The study demonstrated that increasing filter thickness decreases both INAK and ESAK values, with the most significant dose reduction occurring at 2 mm thickness. Optimal image quality and effective dose reduction were observed with the 1 mm filter at 80 kV, reducing the dose by 14.3% to 20% while maintaining good spatial resolution and contrast. The study concludes that using a 1 mm aluminum filter with 80 kV significantly reduces the effective dose while maintaining image quality. It is recommended that hospitals adopt additional filters, conduct further research with different materials, and optimize exposure factors. Training for radiology technicians on these practices is essential to enhance patient safety and image quality. Keywords: X-ray Equipment, Entrance Surface Air Kerma, Effective Dose, Image Quality.

New crescent moon detection using Circular Hough Transform (CHT)

Over 1.5 billion Muslims worldwide rely on a calendar based on the observation of the new crescent moon, particularly during the Hijri calendar months of Ramadhan, Shawal, and Zulhijjah. Accurately detecting the new crescent moon immediately after its conjunction is essential for ensuring the precision of the calendar, but it poses a technical challenge due to the low contrast between the new crescent moon and its background. This study aimed to solve the challenge of reliably identifying the new crescent moon at this critical phase, which is vital for accurately determining important dates that signify religious events. It intended to create and verify a computer vision model that would greatly improves the precision and efficiency of identifying a new crescent moon based on images. This will assist in precisely identifying important dates relevant to Muslim religious practices. The methodology employs Gaussian Blur for the purpose of image smoothing and Adaptive Thresholding to enhance image contrast. In addition, frame extraction and pre-processing techniques were employed to optimize image quality. The Circular Hough Transform (CHT) technique was used to accurately detect the new crescent moon, while the OpenCV software package helped to implement all of these methods, thus, providing a strong foundation for precisely identifying the new crescent moon. Findings of this study, which involved observations at Kolej Ugama Sultan Zainal Abidin (KUSZA) Observatory, Teluk Kemang Observatory, and Miri Observatory, indicate that the utilization of image processing techniques results in significant improvements in both the efficiency and precision of identifying and detecting the new crescent moon. These enhancements exceed the performance of conventional digital imaging methods employed during regular observations. The model’s processing rate surpasses the usual observation efficiency and showcases exceptional accuracy in distinguishing images that feature the new crescent moon from those that do not. In conclusion, the proposed model demonstrates an effective and efficient methodology for improving the precision of lunar calendar management and the quick planning of important Islamic religious events in accordance with the lunar cycle. This technological advancement offers a reliable method for accurately seeing the crescent moon, which has important implications for enhancing the precision of lunar-based calendars and coordinating important Islamic religious occasions.

Development of a user-friendly calculator for a pediatric split-bolus polytrauma computed tomography protocol

We present here a user-friendly calculator for the setting of a pediatric split-bolus polytrauma computed tomography (CT) protocol with a mixed arterial and venous phase, aiming to both reduce radiation dose and improve workflow while assuring optimal image quality. All the different parameters are calculated based on patient’s weight with rapid computation of the injected contrast media and saline volumes, injection’s flow rate, injection’s timing, and optimal acquisition time. The designed calculator is built in a widely available Google Sheets file, accessible by a quick response (QR) code. Although polytrauma imaging represents the main goal of the technique, it can be used in a wide variety of contexts, including oncological, infectious, and vascular pathologies.Graphical

Imaging of Upper Tract Urothelial Carcinoma.

Upper tract urothelial carcinoma (UTUC) originates in the renal pelvis or ureters and typically affects elderly patients, with its incidence increasing over the past few decades. UTUC is a distinct clinical entity with more aggressive clinical behavior than that of lower tract urothelial carcinoma. Due to the significant challenge of acquiring an adequate tissue sample for biopsy, comprehensive risk stratification is required for treatment planning, including radical nephroureterectomy and kidney-sparing management. Imaging plays an important integrated role in risk assessment along with endoscopy and pathologic examination. Lifelong surveillance is required after treatment due to the high incidence of recurrent and metachronous tumors. Lynch syndrome is a frequently unrecognized genetic disorder associated with UTUC that warrants specific attention in patient management. UTUC may manifest with diverse imaging findings, including filling defects, wall thickening, and mass-forming lesions. CT urography is the preferred modality for diagnosis and staging or restaging of UTUC, with numerous technical variations. Efforts have been made to optimize image quality and radiation exposure. Due to its poor sensitivity for small lesions, use of MR urography is limited to special clinical scenarios (eg, when patients have contraindications to iodinated contrast agents). Fluorine 18 fluorodeoxyglucose PET helps to detect metastatic lesions. Image-guided biopsy may be considered for uncertain lesions. Radiologists need to be familiar with the imaging findings and their differential diagnoses. ©RSNA, 2024 Supplemental material is available for this article.

Cataract Epidemiology and Prevention: Strategies for Reducing Global Burden

Cataract, characterized by the clouding of the eye's clear lens, is the leading cause of blindness worldwide. To achieve optimal image quality on the retina, the human lens and cornea must first refract light accurately. With aging, the human lens undergoes physical, biochemical, and morphological changes, leading to opacification. The primary mechanisms of cataract formation involve the modification, aggregation, and precipitation of crystalline. While most cataracts result from age-related degeneration, they can also arise secondary to trauma or as a consequence of other diseases, though cataracts are rare in children. This review article provides an in-depth examination of the anatomy and physiology of the lens, different types of cataracts—including diabetic, pediatric, and age-related cataracts—and the management of cataracts through surgical and pharmacological treatments.

Low-Field MRI for Dental Imaging in Pediatric Patients With Supernumerary and Ectopic Teeth: A Comparative Study of 0.55 T and Ultra-Low-Dose CT.

This study sought to elucidate the diagnostic performance of 0.55 T magnetic resonance imaging (MRI) for pediatric dental imaging, specifically in terms of the image quality (IQ) for detecting ectopic and/or supernumerary teeth, compared with routine ultra-low-dose computed tomography (ULD-CT) of the jaw. A total of 16 pediatric patients (mean age: 12.4 ± 2.6 years, range: 9-17 years) with ectopic and/or supernumerary teeth screened from January 2023 to January 2024 were enrolled in this prospective, single-center study. All patients underwent ULD-CT as the clinical reference standard and 0.55 T MRI as the study scan on the same day. A 0.6-mm isotropic 3-dimensional T1w FLASH sequence was developed with a dedicated field of view of the upper and lower jaws. ULD-CT was performed using a new single-source computed tomography (CT) scanner equipped with a tin filter (Sn100, slice thickness: 1 mm, quality reference mAs: 24). The IQ for the tooth axis, the tooth length, the tooth root, root resorptions, cysts, the periodontal ligament space, and the mandibular canal was evaluated twice by 3 senior readers using a 5-point Likert scale (LS) (LS score of 1: insufficient, 3: reduced IQ but sufficient for clinical use, and 5: perfect) and compared between both methods. Subsequently, the results were dichotomized into nonvalid (LS score of ≤2) and valid (LS score of ≥3) for clinical use. A total of 49 ectopic and/or supernumerary teeth in 16 pediatric patients were investigated using ULD-CT (CTDI: 0.43 ± 0.09 mGy) and 0.55 T MRI. The mean MRI acquisition time was 9:45 minutes. Motion artifacts were nonsignificantly different between 0.55 T MRI and ULD-CT (P = 0.126). The IQ for the tooth axis, the tooth root, root resorptions, and cysts was similar between the methods. The IQ for the periodontal ligament space and tooth length favored ULD-CT by 14% (confidence interval [CI]: 4.3%-24%) and 7.5% (CI: 1.8%-13%), respectively, whereas that for the mandibular canal favored 0.55 T MRI by -35% (CI: -54%-16%). Sufficient IQ was found especially for cystic lesions (CT: 100% sufficient, MRI: 95% sufficient), the tooth root (CT: 100%, MRI: 98%), root resorptions (CT: 94%; MRI: 85%), the tooth axis (CT: 100%; MRI: 98%), and the tooth length (CT: 99%; MRI: 91%). The findings indicate that 0.55 T MRI is a feasible, radiation-free technique for delineating ectopic and/or supernumerary teeth in pediatric patients. Nevertheless, to date, 0.55 T MRI has not yet been able to provide an optimal IQ for all anatomical tooth and jaw structures. In cases of advanced clinical indications that require optimal spatial resolution, high-resolution CT or cone-beam CT may still be necessary.

Vector quantization-driven image compression through multi-objective evolutionary algorithms

In recent years, information consumption among the population has increased, especially through the widespread use of digital images and videos. Consequently, the demand for efficient compression methods has escalated, aiming to facilitate both data storage and transmission while adapting to the unique requirements of diverse problems. The image compression problem has been explored in several works through the lens of vector quantization (VQ) by adopting a single-objective approach to achieve optimal quality results but with a fixed compression level. In contrast, this investigation introduces a groundbreaking multi-objective compression approach that simultaneously optimizes image quality and compression level. This is achieved by selecting the most representative information to construct an adequate codebook while minimizing its size. The proposed method was evaluated on a curated selection of well-known public domain images, using different types of multi-objective evolutionary algorithms, including Pareto-, indicator- and decomposition-based approaches. The compressed images produced were assessed through the application of established quality indicators drawn from the expansive realm of image processing literature, ensuring the reliability and validity of our findings. The results demonstrate the proposed method’s ability to adapt to the intrinsic characteristics of each image, removing the maximum amount of redundant information presented. Furthermore, the multi-objective nature of the proposed approach allows us to obtain solutions with different levels of trade-off between quality and compression, opening up new possibilities in the field and demonstrating the potential to address the evolving challenges posed by the escalating volume of information in the digital landscape.

An X-ray fluorescence experimental method for photon-counting detector in computed tomography system

The X-ray fluorescence (XRF) spectrum of specific elements can be utilized in energy calibration, energy resolution measurement, and analysis of energy response functions for photon-counting detectors (PCDs). The applications can be beneficial for PCD threshold accuracy, performance verification, and optimizing image quality. In previous literature, the experimental configuration for the XRF spectrum typically employed a vertical configuration to avoid the influence of the primary X-ray beam. However, such an experimental configuration is constrained by the fixed position of the X-ray source and detector in the computed tomography (CT) system. Hence, the purpose of this study is to investigate a horizontal configuration for XRF measurements and compare the differences in XRF spectrum with vertical configuration. The results indicate that the spectral characteristics of the horizontal and vertical configurations are similar, suggesting that the horizontal configuration could be applied for energy calibration and spectral analysis in PCD-CT systems.

Comparison between Magnetic Resonance Elastography and Diffusion-Weighted Imaging in Differentiation of Benign and Malignant Hepatic Focal Lesions

Abstract Background With the widespread use of cross-sectional imaging techniques, the detection of focal liver lesions (FLLs) has become increasingly common. Many FLLs are incidental, and characterization with imaging is an effective means to reduce the need for invasive biopsies for histological confirmation. Objective To compare between MRE and diffusion–weighted imaging for differentiating benign and malignant hepatic focal lesions. Methods This Prospective study was conducte at department of Radiodiagnosis of National Hepatology and Tropical Medicine Research Institute “NHTMRI” in Cairo, Egypt, on 50 patients. Results Our study results revealed that in the comparison between diffusion and MRE to detect malignant lesions, the sensitivity and specificity of diffusion was 100% and 40.9% respectively, but for MRE was 89.3% and 100%, Also showed that MRE is significantly superior to DWI for distinguishing between malignant and benign FLLs, with 89% sensitivity, 100% specificity, and accuracy for MRE. Among all FLLs. the most frequent focal lesion HCC by 48.0% followed by hemangioma and inflammatory lesions by 26% & 12% respectively. Conclusion MRE provides a non-invasive quantitative parameter that may be useful for differentiating common benign and malignant FLLs. MRE performed better than DWI, and shows great promise as a non-invasive alternative to biopsy for the differentiation of benign and malignant FLLs and demonstrates additive value to conventional imaging. However, there is opportunity for further enhancement of the technique, particularly with regard to optimization of image quality and evaluation of smaller FLLs.

Impact of an institutional process change adopting end-systolic coronary CTA acquisition and automated dose selection on patient throughput and image quality

IntroductionGuidelines recommend prospective ECG-triggered mid-diastolic coronary computed tomographic angiography (CCTA) acquisition after achieving optimal heart rate (HR) control in order to optimize scan image quality. With dual-source CCTA, prospective end-systolic acquisition has been shown to be less prone to motion artifacts at higher heart rates and may improve scan and CT laboratory efficiency by allowing CCTA without routine pre-scan beta-blocker (BB) administration. MethodsWe implemented an institutional process change in CCTA performance effective January 2023, comprising a transition from prospective ECG-triggered mid-diastolic acquisitions individually supervised by a physician at the scanner to an algorithmic approach predominately utilizing prospective end-systolic acquisition (200–400 ​ms after R peak), employing an automated dose selection algorithm, without BB administration. All scans were performed on a third-generation 192-slice dual-source scanner. We reviewed 300 consecutive CCTAs done pre- and post-process change in Jan 2022 (phase 0), Jan 2023 (phase 1), and in May 2023 (phase 2) after implementation of a process improvement involving more selective utilization of automated tube potential/current algorithms (CARE kV) to optimize image quality. Coronary segmental image quality was assessed by two experienced CCTA readers by consensus using an 18-segment SCCT model on a 5-point Likert scale (1 ​= ​non-interpretable; 2 ​= ​poor; 3 ​= ​acceptable; 4 ​= ​good; 5 ​= ​excellent). Measures of radiation dose, medication administration, and time required for patient scanning were compared. Logistic regression was used to determine factors associated with patient-level reduction in image quality (IQ) and with repeat scans. ResultsPost-process change, there was a significant reduction in the median overall patient appointment [phase 0: 95 (75–125) min vs. phase 1: 68 (52–88) min and phase 2: 72 (59–90) min; P ​< ​0.001] and scan times [phase 0: 13 (10–16) min vs. phase 1: 8 (6–13) min and phase 2: 9 (7–13) min; P ​< ​0.001]. Median IQ score in both post-process change phases was 4 (4–5) compared to a median score of 5 (4–5) pre-process change (P for comparison <0.001). The majority of segments post-process change had “good” IQ (Phase 1 segmental IQ scores: 5 ​= ​36.7 ​%, 4 ​= ​46.8 ​%, 3 ​= ​13 ​%, 2 ​= ​2.6 ​%, 1 ​= ​0.9 ​%; Phase 2 segmental IQ scores: 5 ​= ​26 ​%, 4 ​= ​49.7 ​%, 3 ​= ​16.3 ​%, 2 ​= ​6.1 ​%, 1 ​= ​1.9 ​%), whereas pre-process change, the majority of segments had “excellent” IQ (Phase 0 segmental IQ scores: 5 ​= ​56 ​%, 4 ​= ​34.3 ​%, 3 ​= ​7.5 ​%, 2 ​= ​1.8 ​%, 1 ​= ​0.4 ​%) There was no significant increase in non-interpretable scans at the patient level. The 22 ​% re-scan rate in phase 1 (vs. 6 ​% in phase 0, P ​= ​.002) improved to 15 ​% in phase 2. While patient related factors of body mass index [adjusted OR obese 2.64, 95 ​% CI 1.12–6.51, P ​= ​0.03; aOR morbidly obese 6.94, 95 ​% CI 2.21–23.52, P ​= ​0.001] and average HR [aOR (per 10 bpm increase) 1.51, 95 ​% CI 1.21–1.9, P ​< ​0.001] were associated with the scoring of any segment as ​≤ ​3 ​at the patient level in a fully adjusted model, the improved phase 2 of the process change was not [aOR 1.61, 95 ​% CI 0.78–3.32]. ConclusionImplementation of an institutional process change utilizing prospective ECG-triggered dual-source end-systolic acquisition avoided the use of beta-blockers, significantly reduced patient appointment and scan times with acceptable diagnostic performance.

The Active Optics System on the Vera C. Rubin Observatory: Optimal Control of Degeneracy among the Large Number of Degrees of Freedom

The Vera C. Rubin Observatory is a unique facility for survey astronomy that will soon be commissioned and begin operations. Crucial to many of its scientific goals is the achievement of sustained high image quality, limited only by the seeing at the site. This will be maintained through an active optics system that controls optical element misalignments and corrects mirror figure error to minimize aberrations caused by both thermal and gravitational effects. However, the large number of adjustment degrees of freedom available on the Rubin Observatory introduces a range of degeneracies, including many that are induced by noise due to imperfect measurement of the wave-front errors. We present a structured methodology for identifying these degeneracies through an analysis of image noise level. We also present a novel scaling strategy based on truncated singular value decomposition that mitigates the degeneracy and optimally distributes the adjustment over the available degrees of freedom. Our approach ensures the attainment of optimal image quality, while avoiding excursions around the noise-induced subspace of degeneracies, marking a significant improvement over the previous techniques adopted for Rubin, which were based on an optimal integral controller. This new approach is likely to also yield significant benefits for all telescopes that incorporate large numbers of degrees of freedom of adjustment.

Anesthesia practices during magnetic resonance imaging in pediatric patients

Aims: The use of magnetic resonance imaging (MRI) is becoming increasingly common for diagnostic and therapeutic purposes in pediatric cases. Among children who are too young to cooperate with the procedure or in those with anxiety, anesthesia may be required to minimize excessive motion and optimize image quality. The aim of this study was to determine the efficacy and associated complications of different anesthesia techniques used during MRI in pediatric patients at our hospital. Methods: Anesthesia follow-up forms and computer records of pediatric patients who had undergone MRI under anesthesia between January 2021 and January 2023 in a training and research hospital in Ankara were retrospectively reviewed. The included patients were categorized into four groups according to their anesthesia maintenance protocols to compare their efficacy and associated complications. Results: Of the 358 included patients, only 2% underwent MRI under general anesthesia with a laryngeal mask airway (LMA), whereas the rest underwent MRI under sedation. In our hospital, the most commonly used technique for MRI under anesthesia in pediatric patients involved sevoflurane inhalation with a simple facemask and airway (54.5%), and the lowest complication rate (0.8%) was observed in those who underwent only anesthesia induction without the administration of an agent for the maintenance of anesthesia. Conclusion: Daily anesthesia is generally considered the most effective and comfortable method for sedation during MRI. The results of this study suggest that anesthesia involving sevoflurane inhalation with a simple face mask applied to preserve spontaneous breathing is an effective and safe method for pediatric patients undergoing MRI.

Optimization of Image Quality in Pelvis Lymphoscintigraphy SPECT/CT Using Discovery NM/CT 670

Abstract Aim A lymphoscintigraphy is a crucial diagnostic tool for visualizing lymph nodes. This scan plays a significant role in determining the treatment and recovery plan for the patients. Due to the small lymph node size, obtaining high-quality images is important to prevent inaccurate results. We aimed to identify the most effective method for enhancing image quality through postprocessing techniques and altering the image reconstruction process. Methods Two data sets were utilized in this study. First, National Electrical Manufacturers Association body phantom was filled with [99mTc]Tc-pertechnetate and prepared with and without any activity in the background of the body. Second, the images of 50 patients who underwent single-photon emission computed tomography/computed tomography imaging received [99mTc]Tc-phytate were collected. Discovery 670 GE gamma camera was used for imaging. Preprocessing of all images was performed by Xeleris and 3DSlicer 5.2.2 software was used for quantification. The effect of image reconstruction parameters such as resolution recovery (RR) algorithm, iteration, subsets, cutoff, and power in Butterworth filter, and full width at half maximum (FWHM) of Gaussian filter was assessed. The image quality index was determined based on contrast-to-noise ratio (CNR), contrast, and coefficient of variation. Results The utilization of the RR algorithm showed notable improvements equal to 74, 35, and 38% of CNR, contrast, and noise reduction, respectively. Significant differences were observed in subiteration of 40 to 112 (p-value &lt; 0.05). The alteration of effective parameters in both smoothing filters yielded statistically significant results, leading to enhanced detectability, reduced noise, and improved contrast simultaneously. Optimum results in terms of noise reduction and CNR were achieved with subiteration (i × s) 4 × 12 using a Gaussian filter with FWHM of 4 or Butterworth filter with power of 10 and cutoff of 1. The highest contrast was observed at subiteration 40 using the Butterworth filter with cutoff of 0.5 and power of 5 or Gaussian filter with 2 mm FWHM. Qualitative analysis by two nuclear medicine specialists validated the quantified image quality. Conclusion The reconstruction setting involving subiteration 48 with the Butterworth filter using cutoff of 1 and power of 10 or 4 mm FWHM of Gaussian filter produced the highest quality images.

Radiation dose and image quality optimization in lumbar spine digital radiography for overweight and obese patients: Phantom study

Background: Lumbar spine radiography plays an important role in routine use for clinical practice in overweight and obese patients. The radiographer is responsible for setting suitable exposure factors for the tradeoffs between radiation dose and image quality (IQ). Objective: To investigate the effect of different kVp values combined with AEC used on radiation dose and IQ for routine lumbar spine radiography in overweight and obese patients. Materials and methods: A 1.5 and 3 cm thickness of frozen pork lard was placed on a pelvis phantom to simulate an overweight and obese patient, respectively. The phantom was imaged at 10 kVp intervals in combination with AEC used. For IQ evaluation, CNR and SNR were calculated, and the observer study was determined using visual grading scores (VGS) with a 5-point Likert scale. The radiation dose was measured using a DAP meter, and then the figure of merit (FOM) was calculated. Results: SNR and CNR for both AP and lateral projection showed a slightly decreasing trend when kVp increased in all groups. The DAP values decreased when the higher kVp was selected with AEC used in each group. The VGS by five radiographers showed good image quality in all groups, while the FOM at 100 and 109 kVp was the highest score for both AP and lateral projections. Conclusion: The optimal kVp setting in this study ranged from 100 to 109 kVp in combination with AEC used, indicating minimal radiation dose, while maintaining diagnostic IQ.

Automated echocardiography view classification and quality assessment with recognition of unknown views.

Interpreting echocardiographic exams requires substantial manual interaction as videos lack scan-plane information and have inconsistent image quality, ranging from clinically relevant to unrecognizable. Thus, a manual prerequisite step for analysis is to select the appropriate views that showcase both the target anatomy and optimal image quality. To automate this selection process, we present a method for automatic classification of routine views, recognition of unknown views, and quality assessment of detected views. We train a neural network for view classification and employ the logit activations from the neural network for unknown view recognition. Subsequently, we train a linear regression algorithm that uses feature embeddings from the neural network to predict view quality scores. We evaluate the method on a clinical test set of 2466 echocardiography videos with expert-annotated view labels and a subset of 438 videos with expert-rated view quality scores. A second observer annotated a subset of 894 videos, including all quality-rated videos. The proposed method achieved an accuracy of for the joint objective of routine view classification and unknown view recognition, whereas a second observer reached an accuracy of 87.6%. For view quality assessment, the method achieved a Spearman's rank correlation coefficient of 0.71, whereas a second observer reached a correlation coefficient of 0.62. The proposed method approaches expert-level performance, enabling fully automatic selection of the most appropriate views for manual or automatic downstream analysis.

Development of fetal magnetic resonance imaging (MRI) phantom.

Anthropomorphic phantoms play an important role in routine clinical practice. They can be used to calibrate magnetic resonance imaging (MRI) scanners, control the diagnostic equipment quality, and reduce the acquisition time. The latter is especially critical for diagnosing fetal anomalies, which requires optimal image quality within the shortest possible time. This paper aims to develop an MRI fetal phantom and determine the materials that best mimic the magnetic resonance (MR) characteristics of its internal organs. Future phantom features will include simulations of fetal limb movements. A single MRI study of a pregnant woman at 20 weeks 3 days of gestation was used as a reference and for image segmentation. Anonymized Digital Imaging and Communication in Medicine (DICOM) files were imported into 3D Slicer v. 5.2.1 for segmentation of the uterus, fetus, and internal organs. Based on the performed segmentation, a three-dimensional model was obtained for printing on a 3D printer. The mold was 3D printed on an Anycubic Photon M3 Max printer. The paper showcases the selection and manufacturing of compositions to simulate the relaxation times of the fetal organs. Formulations for emulsions and carrageenan- and agar-based hydrogels are presented. The selected compositions were used to fill the 3D printed model. Statistical analysis showed no significant differences in absolute and relative signal values obtained from scans of a pregnant woman at 20 weeks and 3 days and a fetal phantom. During the study, an anthropomorphic fetal phantom was constructed, filled with compositions with relaxation times T1 and T2 similar to the control values of the corresponding tissues. The phantom can be used to set up and optimize fetal MRI protocols, train and educate medical students, residents, graduate students, and X-ray technicians, as well as to timely control image quality and equipment serviceability.

High-Frame-Rate Ultrasound Velocimetry in the Healthy Femoral Bifurcation: A Comparative Study Against 4-D Flow Magnetic Resonance Imaging

ObjectiveLocal flow dynamics impact atherosclerosis yet are difficult to quantify with conventional ultrasound techniques. This study investigates the performance of ultrasound vector flow imaging (US-VFI) with and without ultrasound contrast agents in the healthy femoral bifurcation. MethodsHigh-frame-rate ultrasound data with incremental acoustic outputs were acquired in the femoral bifurcations of 20 healthy subjects before (50V) and after contrast injection (2V, 5V and 10V). 2-D blood-velocity profiles were obtained through native blood speckle tracking (BST) and contrast tracking (echo particle image velocimetry [echoPIV]). As a reference, 4-D flow magnetic resonance imaging (4-D flow MRI) was acquired. Contrast-to-background ratio and vector correlation were used to assess the quality of the US-VFI acquisitions. Spatiotemporal velocity profiles were extracted, from which peak velocities (PSV) were compared between the modalities. Furthermore, root-mean-square error analysis was performed. ResultsUS-VFI was successful in 99% of the cases and optimal VFI quality was established with the 10V echoPIV and BST settings. A good correspondence between 10V echoPIV and BST was found, with a mean PSV difference of -0.5 cm/s (limits of agreement: -14.1–13.2). Both US-VFI techniques compared well with 4-D flow MRI, with a mean PSV difference of 1.4 cm/s (-18.7–21.6) between 10V echoPIV and MRI, and 0.3 cm/s (-23.8–24.4) between BST and MRI. Similar complex flow patterns among all modalities were observed. Conclusion2-D blood-flow quantification of femoral bifurcation is feasible with echoPIV and BST. Both modalities showed good agreement compared to 4-D flow MRI. For the femoral tract the administration of contrast was not needed to increase the echogenicity of the blood for optimal image quality.

Age-related wall shear stress changes assessed by vascular vector flow mapping in the carotid arteries of healthy adults: a cross-sectional study.

Wall shear stress (WSS) is related to the pathogenesis of atherosclerosis. WSS is affected by a variety of hemodynamic factors, and there is still a lack of accurate and objective methods for measuring it. This study sought to evaluate hemodynamic changes in WSSmaximum (max), WSSmean, WSSminimum (min) in the common carotid artery of healthy adults of different ages using vascular vector flow mapping (VFM). A retrospective analysis was conducted on 70 healthy volunteers aged 20-89 years who were recruited from our Ultrasound Department between February 2021 and June 2021. An ultrasound system with a 3-15 MHz probe was used to determine regions of interest (ROIs) of the common carotid artery. VFM-based WSS measurements were obtained by selecting ROIs with optimal image quality from three full cardiac cycles. The participants were divided into the following seven age groups: the 20s group, the 30s group, the 40s group, the 50s group, the 60s group, the 70s group, and the 80s group. The WSS parameters were compared among the age groups. An analysis of variance or a Kruskal-Wallis test was used to evaluate the difference among the groups, and a Pearson analysis and linear regression were used for the correlation and trend analysis. The WSS parameters were quantified using vascular VFM software. The WSSmax, WSSmean, WSSmin differed among the age groups and gradually decreased with age, the elderly were significantly lower than the young. The Pearson correlation coefficient of the WSSmax and age was -0.556 (P<0.001), that of the WSSmean and age was -0.461 (P<0.001), and that of the WSSmin and age was -0.308 (P<0.001). The WSS parameters with age are negatively correlated the carotid intima-media thickness differed between the groups. The carotid WSSmax, WSSmean, WSSmin can be quantitatively and visually analyzed using the vascular VFM technique. In healthy adults of different ages, the carotid WSSmax, WSSmean, WSSmin decreased with age. Our findings about the normal values of carotid WSS maybe have clinical reference value for future studies.