Faster Scan Times Research Articles

Second generation stationary chest tomosynthesis with faster scan time and wider angular span.

Digital tomosynthesis has shown potential for increasing specificity and sensitivity compared to radiography for low-dose chest imaging. Prior investigation of the s-DCT system indicated potential, but additional iteration with improved scan speed, power, and angular span was necessary for translation. The study aims to demonstrate and characterize a second-generation stationary digital chest tomosynthesis (s-DCT) scanner with increased x-ray energy, tube current, and larger angular span. The second-generation s-DCT system employed a meter-long linear carbon nanotube (CNT) source array integrated with a digital detector and patient imaging table. Tube output, focal spot size, modulation transfer function (MTF), artifact spread function (ASF), and imaging performance were evaluated. A lung phantom with simulated nodules was imaged for clinical task-based demonstration. The scanner achieved a 6s scan time, significantly improved from the prior generation's 16s. The x-ray tube exhibited good current stability, with 20.4±0.6mA tube current and focal spot size aligned with specifications (IEC 0.8). The MTF confirmed enhanced spatial resolution of 2.4lp/mm, comparable to commercial chest tomosynthesis systems. The ASF indicated improved depth resolution (5.2mm, previously 9.5mm). Phantom imaging showcased visualization of both high and low-attenuation lung nodules. The second-generation s-DCT system exhibited improved performance in terms of tube power, scan time, and image quality. Enhanced in-plane and depth resolution, along with faster imaging, suggest potential clinical benefits for improved diagnoses. Further clinical validation is warranted to ascertain the system's clinical utility.

High-resolution hybrid micro-CT imaging pipeline for mouse brain region segmentation and volumetric morphometry.

Brain region segmentation and morphometry in humanized apolipoprotein E (APOE) mouse models with a human NOS2 background (HN) contribute to Alzheimer's disease (AD) research by demonstrating how various risk factors affect the brain. Photon-counting detector (PCD) micro-CT provides faster scan times than MRI, with superior contrast and spatial resolution to energy-integrating detector (EID) micro-CT. This paper presents a pipeline for mouse brain imaging, segmentation, and morphometry from PCD micro-CT. We used brains of 26 mice from 3 genotypes (APOE22HN, APOE33HN, APOE44HN). The pipeline included PCD and EID micro-CT scanning, hybrid (PCD and EID) iterative reconstruction, and brain region segmentation using the Small Animal Multivariate Brain Analysis (SAMBA) tool. We applied SAMBA to transfer brain region labels from our new PCD CT atlas to individual PCD brains via diffeomorphic registration. Region-based and voxel-based analyses were used for comparisons by genotype and sex. Together, PCD and EID scanning take ~5 hours to produce images with a voxel size of 22 μm, which is faster than MRI protocols for mouse brain morphometry with voxel size above 40 μm. Hybrid iterative reconstruction generates PCD images with minimal artifacts and higher spatial resolution and contrast than EID images. Our PCD atlas is qualitatively and quantitatively similar to the prior MRI atlas and successfully transfers labels to PCD brains in SAMBA. Male and female mice had significant volume differences in 26 regions, including parts of the entorhinal cortex and cingulate cortex. APOE22HN brains were larger than APOE44HN brains in clusters from the hippocampus, a region where atrophy is associated with AD. This work establishes a pipeline for mouse brain analysis using PCD CT, from staining to imaging and labeling brain images. Our results validate the effectiveness of the approach, setting a foundation for research on AD mouse models while reducing scanning durations.

Efficient pulse sequence design framework for high-dimensional MR fingerprinting scans using systematic error index.

For effective optimization of MR fingerprinting (MRF) pulse sequences, estimating and minimizing errors from actual scan conditions are crucial. Although virtual-scan simulations offer an approximation to these errors, their computational demands become expensive for high-dimensional MRF frameworks, where interactions between more than two tissue properties are considered. This complexity makes sequence optimization impractical. We introduce a new mathematical model, the systematic error index (SEI), to address the scalability challenges for high-dimensional MRF sequence design. By eliminating the need to perform dictionary matching, the SEI model approximates quantification errors with low computational costs. The SEI model was validated in comparison with virtual-scan simulations. The SEI model was further applied to optimize three high-dimensional MRF sequences that quantify two to four tissue properties. The optimized scans were examined in simulations and healthy subjects. The proposed SEI model closely approximated the virtual-scan simulation outcomes while achieving hundred- to thousand-times acceleration in the computational speed. In both simulation and in vivo experiments, the optimized MRF sequences yield higher measurement accuracy with fewer undersampling artifacts at shorter scan times than the heuristically designed sequences. We developed an efficient method for estimating real-world errors in MRF scans with high computational efficiency. Our results illustrate that the SEI model could approximate errors both qualitatively and quantitatively. We also proved the practicality of the SEI model of optimizing sequences for high-dimensional MRF frameworks with manageable computational power. The optimized high-dimensional MRF scans exhibited enhanced robustness against undersampling and system imperfections with faster scan times.

Nonuniform sliding-window reconstruction for accelerated dual contrast agent quantification with MR fingerprinting

ObjectiveMR fingerprinting (MRF) can enable preclinical studies of cell tracking by quantifying multiple contrast agents simultaneously, but faster scan times are required for in vivo applications. Sliding window (SW)-MRF is one option for accelerating MRF, but standard implementations are not sufficient to preserve the accuracy of T2*, which is critical for tracking iron-labelled cells in vivo.PurposeTo develop a SW approach to MRF which preserves the T2* accuracy required for accelerated concentration mapping of iron-labelled cells on single-channel preclinical systems.MethodsA nonuniform SW was applied to the MRF sequence and dictionary. Segments of the sequence most sensitive to T2* were subject to a shorter window length, preserving the T2* sensitivity. Phantoms containing iron-labelled CD8+ T cells and gadolinium were used to compare 24× undersampled uniform and nonuniform SW-MRF parameter maps. Dual concentration maps were generated for both uniform and nonuniform MRF and compared.ResultsLin’s concordance correlation coefficient, compared to gold standard parameter values, was much greater for nonuniform SW-MRF than for uniform SW-MRF. A Wilcoxon signed-rank test showed no significant difference between nonuniform SW-MRF and gold standards. Nonuniform SW-MRF outperformed the uniform SW-MRF concentration maps for all parameters, providing a balance between T2* sensitivity of short window lengths, and SNR of longer window lengths.ConclusionsNonuniform SW-MRF improves the accuracy of matching compared to uniform SW-MRF, allowing higher accelerated concentration mapping for preclinical systems.

Evaluasi Perbandingan Informasi Citra MRI Brain Sekuen Diffusion Weighted Imaging Irisan Axial Pada Variasi Nilai SENSE di Instalasi Radiologi RSUD Provinsi NTB

Magnetic Resonance is a radiodiagnostic examination tool in the field of radiology, especially in the medical world. Diffusion Weighted Imaging is a method to assess molecular function and microarchitecture of the human body. DWI signal contrast can be measured with visible diffusion coefficient maps and serves as a tool for treatment response evaluation and disease progression assessment. Parallel imaging techniques involve phased array coils to process signals from a slice, then combine these slices to form an image, reducing scan time by reducing the acquired K-space lines. The formation of Sensitivity Encoding (SENSE) can shorten the insertion of K-space. This study aims to test variations of SENSE values 2.0 and 2.5 in MRI brain examinations with axial DWI sequences that are capable of visualizing anatomical information with fast scan times without compromising image quality, resulting in optimal images. This research is quantitative with an experimental approach. The sample consists of 10 patients using voluntary sampling of MRI Brain with axial DWI sequence and varying SENSE values from July to August 2023. Data were collected through questionnaires filled out by three radiology specialists at the Radiology Installation of the Provincial Hospital of West Nusa Tenggara (RSUD Provinsi NTB). The results of the Wilcoxon test showed a significant difference in anatomical information in MRI brain with axial DWI sequences between SENSE values of 2 and 2.5, with a p-value of 0.012. The mean rank value results indicated a sum of ranks of 280.00 for the SENSE 2 value, demonstrating greater optimality compared to SENSE 2.5. This study concludes that there is a significant difference in anatomical information in MRI brain with axial DWI sequences between SENSE values of 2 and 2.5. SENSE 2 tends to provide more optimal information.

Analysis of Early Stroke Diagnosis Based on Brain Magnetic Resonance Imaging using Machine Learning

Stroke causes paralysis resulting from a hemorrhage in the brain or blockage of blood flow to the brain. It is third leading cause of death in Malaysia, with at least 32 deaths per day, and poses a major challenge to Malaysia's health services. A recent study showed that he could save a patient's life if he received treatment within six hours of a stroke. Unfortunately, Malaysia is facing a shortage of neuroradiologists, hampering efforts to treat its growing number of stroke patients. In this research, used Magnetic Resonance Imaging which is better compare to CT scan and CBCT because MRI will produce more detailed images of soft tissues, ligaments and organs. So that, advanced imaging using magnetic resonance imaging (MRI) has gained more attention than conventional angiography in the diagnosis of acute stroke due to its high spatial resolution and fast scan times. Traditionally, diagnosis was made manually by neuroradiologists during a highly subjective and time-consuming task. Detecting collaterals from MRI images is a challenging task due to the presence of noise and artifacts, small size, and heterogeneous structure of vessels. By the way, this paper is mainly about the early diagnosis of stroke based on brain magnetic resonance imaging using machine learning. Based on the results, can see that the Fuzzy c-means (FCM) and Watershed Transformation (WT) segmentation of brain infarcts which are original image, output of guided filter, gradient magnitude image, output of watershed transform and final detected infarct with morphological operation.

Small animal DXA instrument comparison and validation

Several new peripheral dual-energy X-ray absorptiometry (DXA) devices designed for assessment of bone and body composition in rodents have been developed. We compared the performance (accuracy and precision) of two of these devices, the InAlyzer and the iNSiGHT, to those of an established device, the PIXImus. We measured total body bone mineral content (BMC), bone mineral density (BMD), and body composition (lean and fat mass) on the three DXA devices in 18 male C57Bl/6 J mice (6 each of ages 8, 14, and 24 weeks, weighing 22 to 33 g). DXA body composition measures were compared to whole-body nuclear magnetic resonance (NMR) outcomes. BMC of the femur was also compared to ex vivo micro-computed tomography (microCT). Total body BMD from the InAlyzer and iNSiGHT devices was strongly correlated to that from PIXImus (R2 = 0.83 and 0.82, respectively), but was ~25 % higher than PIXImus. Total body BMC measures by InAlyzer were strongly associated with those from PIXImus (R2 = 0.86), whereas those from iNSiGHT were only weakly correlated (R2 = 0.29). Femur BMC from InAlyzer was strongly correlated with microCT outcomes, whereas iNSiGHT was only weakly correlated. InAlyzer and iNSiGHT fat mass measures were very strongly correlated with PIXImus and NMR outcomes (R2 = 0.91 to 0.97), with slightly weaker associations for lean mass (R2 = 0.81 to 0.76). Short-term precision of InAlyzer and iNSiGHT measurements were excellent, and akin to those from the PIXImus for both body composition and bone measures, ranging between 0.39 and 3.2 %. With faster scan times, closed X-ray source and excellent precision, the new devices are both satisfactory replacements for the now discontinued PIXImus system. However, given the accuracy of the bone and body composition measures, the InAlyzer may be preferable for studies where musculoskeletal changes are the main interest.

Capacitance Estimation for Electrical Capacitance Tomography Sensors Using Digital Processing of Time-Domain Voltage Response to Single-Pulse Excitation

In this paper, a new approach for capacitance measurement for electrical capacitance tomography (ECT) sensors is proposed. The method is based on the digital processing of the time-domain voltage measurements at the sensor electrodes. Furthermore, a robust capacitance estimation algorithm is developed to convert the measured voltage time-series to inter-electrode capacitances. The proposed measurement technique simplifies the electronic design of the ECT sensor and is suitable for use in applications requiring a compact device with a fast scan time. The accuracy and sensitivity of the method are investigated numerically and experimentally using a prototype sensor. In particular, the sensitivity of the estimated capacitance to measurement noise levels is analyzed in detail. Additionally, an analysis of the parameters that affect the accuracy of estimated capacitances is carried out from which we are able to demonstrate that the method is immune to effects such as stray capacitances between the electrodes and the ground. A prototype sensor with an open curved geometry on a millimeter scale is used to test the method empirically. Experimental results obtained for measurements with mineral oil and water are shown and compared against capacitances obtained using a physics-based forward model of the sensor. The inter-electrode capacitances in the range of tens of femtofarads to a few picofarads are estimated and a close match with the forward model results is obtained.

A Two-Branch Neural Network for Short-Axis PET Image Quality Enhancement.

The axial field of view (FOV) is a key factor that affects the quality of PET images. Due to hardware FOV restrictions, conventional short-axis PET scanners with FOVs of 20 to 35 cm can acquire only low-quality PET (LQ-PET) images in fast scanning times (2-3 minutes). To overcome hardware restrictions and improve PET image quality for better clinical diagnoses, several deep learning-based algorithms have been proposed. However, these approaches use simple convolution layers with residual learning and local attention, which insufficiently extract and fuse long-range contextual information. To this end, we propose a novel two-branch network architecture with swin transformer units and graph convolution operation, namely SW-GCN. The proposed SW-GCN provides additional spatial- and channel-wise flexibility to handle different types of input information flow. Specifically, considering the high computational cost of calculating self-attention weights in full-size PET images, in our designed spatial adaptive branch, we take the self-attention mechanism within each local partition window and introduce global information interactions between nonoverlapping windows by shifting operations to prevent the aforementioned problem. In addition, the convolutional network structure tends to consider the information in each channel equally during the feature extraction process. In our designed channel adaptive branch, we use a Watts Strogatz topology structure to connect each feature map to its most relevant features in each graph convolutional layer, substantially reducing information redundancy. Moreover, ensemble learning is adopted in our SW-GCN for mapping distinct features from the two well-designed branches to the enhanced PET images. We carried out extensive experiments on three single-bed position scans for 386 patients. The test results demonstrate that our proposed SW-GCN approach outperforms state-of-the-art methods in both quantitative and qualitative evaluations.

The Use of HU Thresholding in Carotid-Cerebral CT Angiography: A Qualitative Study

Background: CT scans with contrast media administration have been used to confirm the presence of pathology in the blood vessel of the brain. High accuracy and fast scanning time produced by CT scans make this modality the main choice in assessing aneurysm pathology in the brain. Technological advances and the development of CT-helical image acquisition techniques have enabled neuroradiologists to evaluate brain aneurysms in a short time. Magnetic resonance (MR) angiography has also been reported to be useful in the diagnosis of brain aneurysms, but it is generally more time-consuming than 3D CTA, and MRI is very sensitive to movement artifacts.Methods: This research is qualitative research with an observational approach that aims to determine the management of carotid-cerebral CTA artery examination in Premier Bintaro Hospital. Unstructured interviews and documentation are used as study instruments to complete the required data.Results: Cerebral Angiography CT examination technique in Premier Bintaro Hospital uses a bolus tracking scanning technique with ROI monitoring of the Carotid Internal Artery and using triggering of 100-120 HU as a peak enhancement to ROI monitoring. This has been proven to produce optimal enhancement in the Circulus of Willis (CoW) region as Volume of Investigation (VOI) in cerebral Angiography CT-Scan. Post-processing is done by displaying images ranging from axial pre-contrast, axial post-contrast, study (pathology), MIP (Axial, coronal, sagittal), Region of Interest MIP (structure labeling), 3D VRT-bone removal.Conclusion: Scanning technique with bolus tracking and ROI monitoring of the Internal Carotid Artery and using triggering of 100-120 HU as a peak enhancement on ROI monitoring can display the arterial artery image very well so that it can be post-processed easily without reducing quality and related image information.

SPECT at the speed of PET: a feasibility study of CZT-based whole-body SPECT/CT in the post 177Lu-DOTATATE and 177Lu-PSMA617 setting.

To evaluate the feasibility of using the StarGuide (General Electric Healthcare, Haifa, Israel), a new generation multi-detector cadmium-zinc-telluride (CZT)-based SPECT/CT, for whole-body imaging in the setting of post-therapy imaging of 177Lu-labeled radiopharmaceuticals. Thirty-one patients (34-89 years old; mean ± SD, 65.5 ± 12.1) who were treated with either 177Lu-DOTATATE (n=17) or 177Lu-PSMA617 (n=14) as part of standard of care were scanned post-therapy with the StarGuide; some were also scanned with the standard GE Discovery 670 Pro SPECT/CT. All patients had either 64Cu-DOTATATE or 18F-DCFPyL PET/CT prior to first cycle of therapy for eligibility check. The detection/targeting rate (lesion uptake greater than blood pool uptake) of large lesions meeting RECIST 1.1 size criteria on post-therapy StarGuide SPECT/CT was evaluated and compared to the standard design GE Discovery 670 Pro SPECT/CT (when available) and pre-therapy PET by two nuclear medicine physicians with consensus read. This retrospective analysis identified a total of 50 post-therapy scans performed with the new imaging protocol from November 2021 to August 2022. The StarGuide system acquired vertex to mid-thighs post-therapy SPECT/CT scans with 4 bed positions, 3 min/bed and a total scan time of 12 min. In comparison, the standard GE Discovery 670 Pro SPECT/CT system typically acquires images in 2 bed positions covering the chest, abdomen, and pelvis with a total scan time of 32 min. The pre-therapy 64Cu-DOTATATE PET takes 20 min with 4 bed positions on GE Discovery MI PET/CT, and 18F-DCFPyL PET takes 8-10 min with 4-5 bed positions on GE Discovery MI PET/CT. This preliminary evaluation showed that the post-therapy scans acquired with faster scanning time using StarGuide system had comparable detection/targeting rate compared to the Discovery 670 Pro SPECT/CT system and detected large lesions defined by RECIST criteria on the pre-therapy PET scans. Fast acquisition of whole-body post-therapy SPECT/CT is feasible with the new StarGuide system. Short scanning time improves the patients' clinical experience and compliance which may lead to increased adoption of post-therapy SPECT. This opens the possibility to offer imaged-based treatment response assessment and personalized dosimetry to patients referred for targeted radionuclide therapies.

Analisis Karakteristik Antivirus Berdasarkan Aktivitas Malware menggunakan Analisis Dinamis

Malware, short for “Malicious Software”, is a program specifically designed to perform an activity that can harm software on a victim's device. Examples of commonly found malware include trojans, ransomware and downloaders. It is important for computer users to recognize and avoid malware when using computer devices. Therefore, computer users can overcome malware attacks by using protection software specifically for computer devices using Antivirus software designed to prevent, find, detect, and remove the types of malware that have been mentioned previously. In this study, the dynamic analysis method is used to determine malware activity by running it and monitoring the activity that occurs. This method is usually used to identify the actions that malware performs when it runs. The results showed that the higher the number of malware activities, the higher the metrics tested on the antivirus, such as CPU, memory, disk, and scan time. Regarding the removable drive protection feature, Avast antivirus is relatively more efficient compared to other antiviruses because it has an average CPU usage, low memory, a fairly high detection rate, and fast scan times. Kaspersky Antivirus is relatively the most effective in detecting malware samples with the highest detection rate of 100%. Meanwhile, the Windows Defender antivirus is relatively the weakest in terms of detection rate because it has the lowest detection rate.

CT in osteoarthritis: its clinical role and recent advances.

Computed tomography (CT) is a widely available imaging method and considered as one of the most reliable techniques in bone assessment. Although CT has limited tissue contrast and needs radiation exposure, it has several advantages like fast scanning time and high spatial resolution. In this regard, CT has unique roles in osteoarthritis (OA) and its variable utilities have been reported. Hence, this review highlights the clinical role of CT in OA of representative joints. In addition, CT showed the several technical advancements recently, for example, acquiring the CT image with standing, obtaining the dual-energy data, and novel photon-counting detector development. Therefore, the recent studies and potential utility of these new CT systems in OA are also discussed.

Overview of the Large Bowel Assessment using Magnetic Resonance Imaging: Different Techniques for Current and Emerging Clinical Applications.

Radiological assessments of the small and large bowel are essential in daily clinical practice. Over X-ray plain films and ultrasound, cross-sectional techniques are considered the most comprehensive imaging modalities. "Cross-sectional techniques" refers to CT and MRI, as stated in the following sentence. In fact, computed tomography and magnetic resonance imaging take great advantage of the three-dimensional appraisal and the extensive evaluation of the abdominal cavity, allowing intestinal evaluation as well as detection of extra-intestinal findings. In this context, the chief advantage of computed tomography is the fast scan time, which is crucial for emergency cases. Nonetheless, it is undeniably impaired using ionizing radiation. As the awareness of radiation exposure is a topic of increasing importance, magnetic resonance imaging is not only becoming a mere alternative but also a primary imaging technique used in assessing intestinal diseases. Specifically, the evaluation of the large bowel through MRI can still be considered relatively uncharted territory. Although it has demonstrated superior accuracy in the assessment of some clinical entities from inflammatory bowel disease to rectal carcinoma, its role needs to be consolidated in many other conditions. Moreover, different technical methods can be applied for colonic evaluation depending on the specific disease and segment involved. This article aims to provide a thorough overview of the techniques that can be utilized in the evaluation of the large bowel and a discussion on the major findings in different colonic pathologies of primary interest.

Use of a novel helical fan beam imaging system for computed tomography of the head and neck in sedated standing horses: 120 cases (2019-2020).

To evaluate the diagnostic capabilities of a novel helical fan beam CT system used for imaging of horses with clinical problems of the head and neck. 120 horses. Medical records were reviewed of horses presented for CT of the head or neck at 2 university hospitals. The following data were recorded: age, sex, breed, presenting complaint, sedation used for imaging, scanning time, procedure time, other diagnostic imaging methods performed, imaging diagnosis, clinical diagnosis, and complications during imaging. Quarter Horses and Warmbloods were the most common breeds, and the most common complaint was nasal discharge. The head (101/120 [84%] horses) was scanned most frequently, and the most common diagnoses were primary dental disease and a space-occupying lesion of the paranasal sinuses. Nuchal bursitis was the most common imaging diagnosis in the neck region. Procedure time ranged from 20 to 45 minutes with a scanning time of 30 to 40 seconds. No complications with horse sedation occurred, and horses tolerated scanning well. An imaging diagnosis was more frequently achieved with CT (109/120 [91%] horses) than with planar digital radiography (23/61 [38%] horses). The helical fan beam CT system had fast scanning times and could be used safely for routine imaging of the teeth and sinuses in horses. The caudal extent of scanning in the neck region was limited by the shape of the horse's neck and thorax.

IMAGE COMPARISON ON T2 QTSE LUMBAL EXAMINATION USING GRAPPA TECHNIQUE WITH AND WITHOUT MAGNETIZATION TRANSFER CONTRAST IN DEGENERATIVE DISC DISEASE CASE

Background: The description of Degenerative Disc Disease in MRI lumbar FSE sequence T2WI is seen as a decrease in signal intensity. Patients with cases of Degenerative Disc Disease experience severe low back pain and cannot lie supine for a long time, while MRI is very sensitive to movement. GRAPPA is a parallel imaging technique that can produce images with a fast scan time but is followed by a decreased Signal to Noise Ratio SNR value. This technique needs to be followed by setting other parameters to produce an optimal image, namely by applying Magnetization Transfer Contrast (MTC). Purpose: To compare the quality of image results on lumbar MRI examination of the sagittal T2 qTSE sequence in the case of Degenerative Disc Disease with and without MTC activation. Method: This research was conducted at the dr. Soedono Madiun from August to September 2020. A sample of 16 patients who met the inclusion criteria was taken during the study. The GRAPPA and GRAPPA+MTC technique imagery results on each sample were assessed for the image quality quantitatively based on the SNR and CNR values. Result: Based on the SNR value, the GRAPPA technique and MTC activation have a higher mean than the GRAPPA technique alone. Likewise, with the CNR value, the GRAPPA technique and MTC activation have a higher average than the GRAPPA technique alone. Conclusion: The GRAPPA technique and MTC activation can be applied in Lumbar MRI examination with cases of Degenerative Disc Disease, especially in uncooperative patients.

Evaluation of pediatric malignancies using total-body PET/CT with half-dose [18F]-FDG.

To explore the impact of a true half dose of [18F]-FDG on image quality in pediatric oncological patients undergoing total-body PET/CT and investigate short acquisition times with half-dose injected activity. One hundred pediatric oncological patients who underwent total-body PET/CT using the uEXPLORER scanner after receiving a true half dose of [18F]-FDG (1.85MBq/kg) were retrospectively enrolled. The PET images were first reconstructed using complete 600-s data and then split into 300-s, 180-s, 60-s, 40-s, and 20-s duration groups (G600 to G20). The subjective analysis was performed using 5-point Likert scales. Objective quantitative metrics included the maximum standard uptake value (SUVmax), SUVmean, standard deviation (SD), signal-to-noise ratio (SNR), and SNRnorm of the background. The variabilities in lesion SUVmean, SUVmax, and tumor-to-background ratio (TBR) were also calculated. The overall image quality scores in the G600, G300, G180, and G60 groups were 4.9 ± 0.2, 4.9 ± 0.3, 4.4 ± 0.5, and 3.5 ± 0.5 points, respectively. All the lesions identified in the half-dose images were localized in the G60 images, while 56% of the lesions could be clearly identified in the G20 images. With reduced acquisition time, the SUVmax and SD of the backgrounds were gradually increased, while the TBR values showed no statistically significant differences among the groups (all p > 0.1). Using the half-dose images as a reference, the variability in the lesion SUVmax gradually increased from the G180 to G20 images, while the lesion SUVmean remained stable across all age groups. SNRnorm was highly negatively correlated with age. Total-body PET/CT with a half dose of [18F]-FDG (1.85MBq/kg, estimated whole-body effective dose: 1.76-2.57mSv) achieved good performance in pediatric patients, with sufficient image quality and good lesion conspicuity. Sufficient image quality and lesion conspicuity could be maintained at a fast scanning time of 60s with half-dose activity.

Deep automatic segmentation of brain tumours in interventional ultrasound data

Abstract Intraoperative imaging can assist neurosurgeons to define brain tumours and other surrounding brain structures. Interventional ultrasound (iUS) is a convenient modality with fast scan times. However, iUS data may suffer from noise and artefacts which limit their interpretation during brain surgery. In this work, we use two deep learning networks, namely UNet and TransUNet, to make automatic and accurate segmentation of the brain tumour in iUS data. Experiments were conducted on a dataset of 27 iUS volumes. The outcomes show that using a transformer with UNet is advantageous providing an efficient segmentation modelling long-range dependencies between each iUS image. In particular, the enhanced TransUNet was able to predict cavity segmentation in iUS data with an inference rate of more than 125 FPS. These promising results suggest that deep learning networks can be successfully deployed to assist neurosurgeons in the operating room.

High-speed flat-detector computed tomography for temporal bone imaging and postoperative control of cochlear implants.

PurposeFlat-detector computed tomography (FD-CT) is the standard for cochlear implant (CI) imaging. FD-CT systems differ in technical characteristics. Our aim was an evaluation of two different FD-CT generations with different protocols and hardware regarding image quality, radiation dose, and scan time.MethodsTwo temporal bone specimens (− / + CI = TB0/TB1) were scanned using three different scanners: two FD-CT systems with different scanning protocols (standard FD-CT: 20 s 70 kV, 20 s 109 kV; high-speed FD-CT [HS-FD-CT]: 7 s 109 kV, 9 s 109 kV, 14 s 72 kV) and MS-CT (5 s 120 kV). Acquired datasets were evaluated in consensus reading regarding qualitative and quantitative parameters: addressing CI- and cochlea-specific parameters, cochlea delineation, lamina spiralis ossea visibility, distinction of single CI electrodes, determination of intracochlear implant position, stapes delineation, and mastoidal septation were assessed. Addressing protocol-specific parameters, radiation dose (dose-length-product/DLP), and scan time were assessed.Results Two HS-FD-CT protocols (14 s/9 s) provide higher or equivalent diagnostic information regarding CI- and cochlea-specific parameters compared to both standard FD-CT protocols. The fastest HS-FD-CT protocol (7 s)—providing inferior diagnostic information compared to all other FD-CT protocols—still exceeds MS-CT. The highest DLP was recorded for the 14 s HS-FD-CT protocol (TB1 = 956 mGycm); the lowest DLPs were recorded for the 7 s HS-FD-CT protocol (TB0 = 188 mGycm) and for MS-CT (TB0 = 138 mGycm), respectively. HS-FD-CT allows a significant reduction of scan time compared to standard FD-CT.ConclusionHigh-speed FD-CT improves visualization of temporal bone anatomy and postoperative assessment of CIs by combining excellent image quality, fast scan time, and reasonable radiation exposure.

Cone Beam Computed Tomography Assessment of Cervical Spine Bone Density

Age-related loss of bone density is a characteristic of osteoporosis, leading to reduced bone strength and increased risk of fracture. In spine surgery patients, osteoporosis also leads to poor outcomes, including pedicle screw loosening, proximal junctional failure, cage subsidence, and adjacent segment disease. Osteoporosis screening is generally performed using dual energy X-ray absorptiometry (DXA) to assess bone density. Cone beam computed tomography (CBCT) is widely used in orthopedic surgeries, including spine surgeries, and in dental and maxillofacial surgery to visualize teeth and jaws for pathology, surgical planning for jaw and TMJ joint reconstruction, structural maxillofacial deformity, pre-operative implant site assessment, 3D cephalometry, and appropriate treatment planning. CBCT is also used for evaluation of cervical vertebrae in skeletal maturation - growth assessment, diagnosis of obstructive sleep apnea, and temporomandibular disorders. In comparison to traditional computed tomography (CT), CBCT introduces several advantages including high spatial resolution (favorable for bone architecture evaluation); high image accuracy; low cost, faster scan time, ease of use, compact machinery, and low radiation exposure. Few studies have investigated the potential use of CBCT images for opportunistic assessment of bone health as an alternative to traditional CT and DXA. This study investigates whether bone density in the C3 vertebrae as determined by CBCT image analysis aligns with previously known trends of age-related bone loss in women post-menopause. Specifically, this study examines changes in bone density of the C3 vertebrae in females, beginning from puberty to post-menopause to late adulthood. Since the use of CBCT beyond dentistry is not well-established, the overarching goal of this study is to provide support for the reliability of dental CBCT images in the determination of bone health for orthopedic applications. This study aims to provide support for the reliability of cone beam CT in allowing for measurements of bone density. The use of CBCT for opportunistic screening of osteoporosis and potentially orthopedic surgeries is highly relevant for medical and dental professionals. The various advantages of CBCT, including high accuracy, low costs, and greater convenience strengthens its position as a potential alternative to traditional CT. Also, as a result of longer life expectancies, more osteoporotic patients are visiting dental clinics, and existing CBCT scans could be utilized to assess osteoporosis risk. Cone beam scans of 416 female patients with ages ranging from 10 to 93 years were obtained between 2010 - 2019. CBCT scans included visualization of the patient's skull, jaw, facial bones, and upper portion of the cervical spine. Sagittal views of the scans were analyzed, with a specific focus on the C3 vertebrae. ImageJ analysis was used to quantify the intensity of the C3 vertebrae region of interest, as a measure of bone density after calibration. Intensity of the muscle area adjacent to the C3 vertebrae and intensity of air in the lungs were measured for the internal calibration of CT Hounsfield units (HU). A linear and spline lines of fit showing changes in bone density values as a function of age were generated to display the overall decline in bone density in females. The linear lines of fit, confidence intervals, linear equations, and R values were calculated using JMP statistical software based on measurements retrieved from the 416 patient scans. A decline in bone density with age was observed (-2.83 HU/year, p< 0.0001). A rapid decline was observed after 50 years of age (-3.72 HU/year, p=0.0001). These findings are consistent with previously established trends depicting changes in BMD as a function of age in females, such that peak loss of bone density occurs during the first few year's post-menopause, beginning around ages 50 to 54. The finding that female subjects aged 50-93 years exhibited a significant decrease in bone density is in line with scientific literature exploring the increased prevalence of osteoporosis in postmenopausal women. The ability to identify these established trends using CBCT scans provides evidence for the utility of obtaining bone density measurements through CBCT image analysis. Our findings may be useful in providing evidence in support of CBCT scans as an alternative method of osteoporosis screening and assessment of bone quality in orthopedic and dental surgery patients. Notable limitations of the present study include the exclusion of body mass index (BMI) and race, among other demographic information. Further efforts to obtain this demographic information would be crucial in developing a more complete understanding of our sample data.