Pediatric CT Research Articles

Pediatric contrast-enhanced chest CT on a photon-counting detector CT: radiation dose and image quality compared to energy-integrated detector CT.

Photon counting detector (PCD) CT benefits from reduced noise compared with conventional energy-integrating detector (EID) CT, which should translate to improved image quality and reduced radiation exposure for pediatric patients undergoing chest CT with IV contrast. To determine the differences in radiation exposure and image quality of PCD CT and EID CT in pediatric chest CT with intravenous (IV) contrast. In this institutional review board-approved retrospective observational study, 20 scan pairs (20 PCD CT; 20 EID CT) for children who underwent chest CT with IV contrast on both a PCD CT (Siemens NAEOTOM Alpha) and an EID CT (Siemens SOMATOM Definition Edge or Force) within 12months were reviewed independently by three pediatric radiologists for three subjective quality features on 5-point Likert scales: overall quality, small structure delineation, and motion artifact. Objective measures of image quality (image noise, signal-to-noise ratio, and contrast-to-noise ratio) were assessed by a single radiologist in several locations in the chest through region of interest measurement of Hounsfield units (HU) and standard deviation. Patient-related and radiation exposure parameters were collected for each scan and summarized with median and interquartile range (IQR). The Wilcoxon rank-sum test was utilized to compare groups. A P < 0.05 indicated statistical significance. Inter-observer agreement of subjective image quality metrics was analyzed using weighted kappa. Age (14.2years vs 13.8years, P= 0.15), height (P= 0.13), weight (P= 0.21), and BMI (P = 0.24) did not significantly differ between groups. There were 10 male and 3 female patients. Compared to EID CT, PCD CT showed lower radiation exposure parameters including volumetric CT dose index, 1.7mGy (IQR 1.1-2.4mGy) vs 3.8mGy (IQR 2.0-4.7mGy) (P< 0.01), and size-specific dose estimate, 2.6mGy (IQR 1.8-3.1mGy) vs 5.0mGy (IQR 3.3-6.2mGy) (P< 0.01). Objective image quality of lung parenchyma was improved on the PCD CT scanner, including image noise 119.5 HU (IQR 95.4-135.7 HU) vs 143.1 HU (IQR 125.4-169.8 HU) (P < 0.01), signal-to-noise ratio (SNR) -6.1 (IQR -8.4 to -4.8) vs -4.9 (IQR -5.6 to -3.8) (P= 0.01), and contrast-to-noise ratio -63.9 (-84.1 to -57.5) vs -60.5 (-76.3 to -52.5) (P = 0.01). Motion artifact was improved on the PCD CT scanner (P< 0.01). No significant differences in overall image quality or small structure delineation were identified (P= 0.06 and P= 0.31). PCD CT pediatric chest CT had significantly reduced radiation exposure, improved image quality, and reduced motion artifact compared with EID CT.

Performance of Lung-Nodule Computer-Aided Detection Systems on Standard-Dose and Low-Dose Pediatric CT Scans: An Intraindividual Comparison.

Background: When applying lung-nodule computer-aided detection (CAD) systems for pediatric CT, performance may be degraded on low-dose scans due to increased image noise. Objective: To conduct an intraindividual comparison of the performance for lung nodule detection of two CAD systems trained using adult data between low-dose and standard-dose pediatric chest CT scans. Methods: This retrospective study included 73 patients (32 female, 41 male; mean age, 14.7 years; age range, 4-20 years) who underwent both clinical standard-dose and investigational low-dose chest CT examinations within the same encounter from November 30, 2018 to August 31, 2020 as part of an earlier prospective study. Fellowship-trained pediatric radiologists annotated lung nodules to serve as the reference standard. Both CT scans were processed using two publicly available lung-nodule CAD systems previously trained using adult data: FlyerScan and Medical Open Network for Artificial Intelligence (MONAI). The systems' sensitivities for nodules measuring 3-30 mm (n=247) were calculated when operating at a fixed frequency of two false-positives per scan. Results: FlyerScan exhibited detection sensitivities of 76.9% (190/247; 95% CI: 73.3-80.8%) on standard-dose scans and 66.8% (165/247; 95% CI: 62.6-71.5) on low-dose scans. MONAI exhibited detection sensitivities of 67.6% (167/247, 95% CI: 61.5-72.1) on standard-dose scans and 62.3% (154/247, 95% CI: 56.1-66.5%) on low-dose scans. The number of detected nodules for standard-dose versus low-dose scans for 3-mm nodules was 33 versus 24 (FlyerScan) and 16 versus 13 (MONAI), 4-mm nodules was 46 versus 42 (FlyerScan) and 39 versus 30 (MONAI), 5-mm nodules was 38 versus 33 (FlyerScan) and 32 versus 31 (MONAI), and 6-mm nodules was 27 versus 20 (FlyerScan) and 24 versus 24 (MONAI). For nodules measuring ≥7 mm, detection did not show a consistent pattern between standard-dose and low-dose scans for either system. Conclusions: Two lung-nodule CAD systems demonstrated decreased sensitivity on low-dose versus standard-dose pediatric CT scans performed in the same patients. The reduced detection at low dose was overall more pronounced for nodules measuring less than 5 mm. Clinical Impact: Caution is needed when using low-dose CT protocols in combination with CAD systems to help detect small lung nodules in pediatric patients.

Computed Tomography Diagnostic Reference Levels for Routine Pediatric Examinations in Saudi Arabia: A Systematic Review.

This work aims to review the diagnostic reference levels reported for pediatric patients who underwent routine CT exams in Saudi Arabia. The literature search was conducted in prominent search engines,including PubMed, Science Direct, Google Scholar, EBSCO, ProQuest, and Saudi Digital Library (SDL), which serve as important sources in the fields of radiology, radiography, and medical physics. The search was conducted to identify previous studies that have reported diagnostic reference levels (DRLs) for pediatric CT examinations. Only studies that specifically assessed DRLs in pediatric patients were considered for inclusion. On careful evaluation, eight publications were ultimately chosenout of the 31 that were originally considered. An assessment was made on the volume computed tomographic dose index (CTDIvol) and the dose-length product (DLP) values. The reported range of mean values for DLP (mGy.cm) included in this review for brain, chest, abdomen, abdomen and pelvis, and CAP (chest,abdomen,and pelvis) was 172-1881, 27.3-458.9, 94.5-790.1, 78-236, and 94.2, respectively. Moreover, the reported range of mean values for CTDIvol (mGy) included in this review for the brain, chest, abdomen, abdomenand pelvis, and CAP were 11.7-79.9, 1.2-20.1, 7.4-22.6, 2.6-5.5, and 3.6, respectively. The review emphasizes the need for standardized imaging protocols and DRLsin pediatric CT examinations to optimize radiation doses and patient safety. It recommends the development of annually reviewed comprehensive national DRLs in Saudi Arabia and improved training for technologists and physicians involved in pediatric CT imaging.

Estimation of Radiation Equivalent Dose and Lifetime Attributable Risk from Pediatric CAP CT Examination

Aim: This study aims to estimate equivalent doses (EqDs) and life attributable risks (LARs) for pediatric patients who underwent chest–abdominal–pelvic (CAP) CT examinations in Madinah, Saudi Arabia. Methodology: This retrospective study collected data from 120 pediatric patients who underwent CAP CT examinations. The data were categorized by the age and gender of the pediatric patients. Then, the EqDs were computed using the NCICT (National Cancer Institute dosimetry system for computed tomography) program, and LARs were estimated from the equivalent dose (EqD) results using age- and gender-specific cancer risk models found in the Committee on the Biological Effects of Ionizing Radiation (BEIR) VII Phase 2 (2006). Results: The EqD range was 0.9 to 7.55 mSv for the prostate and colon (males and females), respectively. LARs for female breast and lung cancers were considered to have the highest values among the age groups. Nevertheless, LARs of the colon, liver, and leukemia cancers were higher for males than females. The LAR range of cancer incidence was 0.6 to 63.1 per 100,000 cases for prostate (aged 10–≤15 years) and breast (females aged 1≤–&lt;5 years), respectively. The LAR range of cancer mortality was 0.1 to 41.9 per 100,000 cases for prostate (aged 10–≤15 years) and lung (females aged 1≤–&lt;5 years). Conclusions: LARs of all cancer incidence and mortality from CAP CT examination were higher for pediatric females than males (with an average of 54%). This highlights the importance of considering pediatric patient gender and implementing optimization and protective measures in CAP CT examinations. LARs of breast and lung (for females) and colon (for males) cancers were found to have the highest values among the age groups. However, LARs of cancer incidence and mortality for colon, liver, and leukemia for males were higher than those for females.

Improving Reproducibility of Volumetric Evaluation Using Computed Tomography in Pediatric Patients with Congenital Heart Disease.

The volumetric data obtained from the cardiac CT scan of congenital heart disease patients is important for defining patient's status and making decision for proper management. The objective of this study is to evaluate the intra-observer, inter-observer, and interstudy reproducibility of left ventricular (LV) and right ventricular (RV) or functional single-ventricle (FSV) volume. And compared those between manual and using semi-automated segmentation tool. Total of 127 patients (56 female, 71 male; mean age 82.1months) underwent pediatric protocol cardiac CT from January 2020 to December 2022. The volumetric data including both end-systolic and -diastolic volume and calculated EF were derived from both conventional semiautomatic region growing algorithms (CM, TeraRecon, TeraRecon, Inc., San Mateo, CA, USA) and deep learning-based annotation program (DLS, Medilabel, Ingradient, Inc., Seoul, Republic of Korea) by three readers, who have different background knowledge or experience of radiology or image extraction before. The reproducibility was compared using intra- and inter-observer agreements. And the usability was measured using time for reconstruction and number of tests that were reconfigured before the reconfiguration time was reduced to less than 5min. Inter- and intra-observer agreements showed better agreements degrees in DLS than CM in all analyzers. The time used for reconstruction showed significantly shorter in DLS compared with CM. And significantly small numbers of tests before the reconfiguration is needed in DLS than CM. Deep learning-based annotation program can be more accurate way for measurement of volumetric data for congenital heart disease patients with better reproducibility than conventional method.

Optimal Spectral Performance on Pediatric Photon-Counting CT: Investigating Phantom-Based Size-Dependent kV Selection for Spectral Body Imaging.

The comprehensive evaluation of kV selection on photon-counting computed tomography (PCCT) has yet to be performed. The aim of the study is to evaluate and determine the optimal kV options for variable pediatric body sizes on the PCCT unit. In this study, 4 phantoms of variable sizes were utilized to represent abdomens of newborn, 5-year-old, 10-year-old, and adult-sized pediatric patients. One solid water and 4 solid iodine inserts with known concentrations (2, 5, 10, and 15 mg I/mL) were inserted into phantoms. Each phantom setting was scanned on a PCCT system (Siemens Alpha) with 4 kV options (70 and 90 kV under Quantum Mode, 120 and 140 kV under QuantumPlus Mode) and clinical dual-source (3.0 pitch) protocol. For each phantom setting, radiation dose (CTDIvol) was determined by clinical dose settings and matched for all kV acquisitions. Sixty percent clinical dose images were also acquired. Reconstruction was matched across all acquisitions using Qr40 kernel and QIR level 3. Virtual monoenergetic images (VMIs) between 40 and 80 keV with 10 keV interval were generated on the scanner. Low-energy and high-energy images were reconstructed from each scan and subsequently used to generate an iodine map (IM) using an image-based 2-material decomposition method. Image noise of VMIs from each kV acquisition was calculated and compared between kV options. Absolute percent error (APE) of iodine CT number accuracy in VMIs was calculated and compared. Root mean square error (RMSE) and bias of iodine quantification from IMs were compared across kV options. At the newborn size and 50 keV VMI, noise is lower at low kV acquisitions (70 kV: 10.5 HU, 90 kV: 10.4 HU), compared with high kV acquisitions (120 kV: 13.8 HU, 140 kV: 13.9 HU). At the newborn size and 70 keV VMI, the image noise from different kV options is comparable (9.4 HU for 70 kV, 8.9 HU for 90 kV, 9.7 HU for 120 kV, 10.2 HU for 140 kV). For APE of VMI, high kV (120 or 140 kV) performed overall better than low kV (70 or 90 kV). At the 5-year-old size, APE of 90 kV (median: 3.6%) is significantly higher (P < 0.001, Kruskal-Wallis rank sum test with Bonferroni correction) than 140 kV (median: 1.6%). At adult size, APE of 70 kV (median: 18.0%) is significantly higher (P < 0.0001, Kruskal-Wallis rank sum test with Bonferroni correction) than 120 kV (median: 1.4%) or 140 kV (median: 0.8%). The high kV also demonstrated lower RMSE and bias than the low kV across all controlled conditions. At 10-year-old size, RMSE and bias of 120 kV are 1.4 and 0.2 mg I/mL, whereas those from 70 kV are 1.9 and 0.8 mg I/mL. The high kV options (120 or 140 kV) on the PCCT unit demonstrated overall better performance than the low kV options (70 or 90 kV), in terms of image quality of VMIs and IMs. Our results recommend the use of high kV for general body imaging on the PCCT.

Deep Learning Models for Abdominal CT Organ Segmentation in Children: Development and Validation in Internal and Heterogeneous Public Datasets.

BACKGROUND. Deep learning abdominal organ segmentation algorithms have shown excellent results in adults; validation in children is sparse. OBJECTIVE. The purpose of this article is to develop and validate deep learning models for liver, spleen, and pancreas segmentation on pediatric CT examinations. METHODS. This retrospective study developed and validated deep learning models for liver, spleen, and pancreas segmentation using 1731 CT examinations (1504 training, 221 testing), derived from three internal institutional pediatric (age ≤ 18 years) datasets (n = 483) and three public datasets comprising pediatric and adult examinations with various pathologies (n = 1248). Three deep learning model architectures (SegResNet, DynUNet, and SwinUNETR) from the Medical Open Network for Artificial Intelligence (MONAI) framework underwent training using native training (NT), relying solely on institutional datasets, and transfer learning (TL), incorporating pretraining on public datasets. For comparison, TotalSegmentator, a publicly available segmentation model, was applied to test data without further training. Segmentation performance was evaluated using mean Dice similarity coefficient (DSC), with manual segmentations as reference. RESULTS. For internal pediatric data, the DSC for TotalSegmentator, NT models, and TL models for normal liver was 0.953, 0.964-0.965, and 0.965-0.966, respectively; for normal spleen, 0.914, 0.942-0.945, and 0.937-0.945; for normal pancreas, 0.733, 0.774-0.785, and 0.775-0.786; and for pancreas with pancreatitis, 0.703, 0.590-0.640, and 0.667-0.711. For public pediatric data, the DSC for TotalSegmentator, NT models, and TL models for liver was 0.952, 0.871-0.908, and 0.941-0.946, respectively; for spleen, 0.905, 0.771-0.827, and 0.897-0.926; and for pancreas, 0.700, 0.577-0.648, and 0.693-0.736. For public primarily adult data, the DSC for TotalSegmentator, NT models, and TL models for liver was 0.991, 0.633-0.750, and 0.926-0.952, respectively; for spleen, 0.983, 0.569-0.604, and 0.923-0.947; and for pancreas, 0.909, 0.148-0.241, and 0.699-0.775. The DynUNet TL model was selected as the best-performing NT or TL model considering DSC values across organs and test datasets and was made available as an open-source MONAI bundle (https://github.com/cchmc-dll/pediatric_abdominal_segmentation_bundle.git). CONCLUSION. TL models trained on heterogeneous public datasets and fine-tuned using institutional pediatric data outperformed internal NT models and Total-Segmentator across internal and external pediatric test data. Segmentation performance was better in liver and spleen than in pancreas. CLINICAL IMPACT. The selected model may be used for various volumetry applications in pediatric imaging.

A Smart Approach: Utilizing A Quality Improvement Toolkit To Develop Pediatric And Congenital Cardiac CT Services In A Low-resource Setting

A Smart Approach: Utilizing A Quality Improvement Toolkit To Develop Pediatric And Congenital Cardiac CT Services In A Low-resource Setting

Poster 369: Medial and Lateral Posterior Tibial Slope in the Skeletally Immature: A Cadaveric Study

Objectives: Increased knee posterior tibial slope (PTS) angle is risk factor for primary and secondary ACL injury. Adult biomechanical research indicates that decreasing the PTS may reduce ACL injuries, and osteotomy techniques have been developed to alter tibia slope to reduce risk of re-injury. Pediatric and adolescent athletes have the highest rates of primary and secondary ACL injury, and many in this age group may have abnormal PTS angle. The purpose of this study was to evaluate PTS in medial and lateral tibial plateaus in large database of CT scans, and to develop normative PTS data in this age group. Methods: IRB approval was waived, as the specimens were donated for research, no genetic information was collected, and there were no plans for family contact. 83 pediatric knee CT scans, ranging from ages 1 to 12, were analyzed using OsiriX imaging software. The PTS was evaluated at two distinct points on sagittal CT sections: (1) At the medial tibia plateau and 2) lateral tibial plateau, both aligned with the central part of on a coronal view of the medial femoral and lateral femoral condyles respectively condyle. Results: The average medial PTS angle was 6.56° ± 3.84° and 6.81° ± 3.62° for the lateral PTS. There was not a significant statistical difference between the medial and lateral PTS (P = 0.6632, determined using an independent-samples t-test and analysis of variance). When plotting the age versus PTS, we observed a positive correlation with the medial PTS (R2 = 0.0385) and a negative correlation with the lateral PTS (R2 = 0.0393). Conclusions: The data demonstrate variability in medial and lateral pediatric PTS and provides normative values for pediatric PTS values. For pediatric patients undergoing ACL surgeries, consideration of increased PTS values that are associated with higher rates of recurrent ACL injury may influence surgical treatment techniques. Correction of increased PTS to lower ACL injury risk is performed in adults with major corrective osteotomy surgery, but such procedures have not been performed in children due to osteotomy-induced damage to growth plates. Due to open growth plates, pediatric patients may be treated with minimally invasive guide growth procedures to lower PTS, with minimal complication risk. Guided growth procedures have a long history of successful alignment correction in the coronal plane. Future animal and clinic studies may also demonstrate the safety and effectiveness of guided growth sagittal plane correction as applied to increased PTS. PTS developmental anatomy and its relationship to ACL injury is crucial for surgical advancements, including the use of low risk guided growth interventions to reduce PTS and ACL injury in pediatric patients with high risk of recurrent injury.

Analysis of Deep Learning Image Reconstruction Application for Pediatric Abdominal CT Dose Reduction

Analysis of Deep Learning Image Reconstruction Application for Pediatric Abdominal CT Dose Reduction

Investigating the Effects of Tube Current and Tube Voltage on Patient Dose in Computed Tomography Examinations with Principial Component Analysis and Cluster Analysis: Phantom Study.

The aim of this study was to investigate the effects of tube current and tube voltage choices on patient dose in adult and pediatric CT protocols by qualitative analysis using Principal Component Analysis (PCA), cluster analysis, and statistical analysis.Dose length product (DLP), Effective mAs (Eff. mAs), and volume-weighted CT dose index (CTDIvol) dose descriptors were obtained from 16 adult and pediatric head phantom CT examinations. Different tube voltage and tube current values were selected in both pediatric head and adult head CT imaging protocols, and PCA and cluster analysis were applied to the data obtained for qualitative analysis of the relationship between CTDIvol, Eff. mAs and Total DLP values. The two principial components (PC) with the highest values among those obtained as a result of the PCA method were used. PC1 was 70.97%, and PC2 was 28.03%. In the cluster analysis, it was observed that the values obtained from pediatric and adult phantom CT scans were classified into two different clusters. The correlation coefficient for adult patients was r = 0.998, and for pediatric patients, the correlation coefficient was r = 0.947. When the obtained clusters were examined, the degree of closeness or distance of the variables could be observed. In the study, as a result of the analysis of CTDIvol, Eff. mAs and Total DLP data based on manufacturer data at different kV and mA values with PCA and cluster analysis, it was shown that pediatric patients could be exposed to more radiation than the adult patients.

Photon counting detector computed tomography in pediatric cardiothoracic CT imaging

Abstract Photon-counting detector computed tomography (PCD-CT) is the most recent advancement in CT technology and has the potential to change clinical practice. Unlike conventional energy-integrated-detector (EID) that uses a two-step process to convert X-rays into a digital signal, PCD-CT directly converts photon energies into electronic signal. The advantages of PCD-CT over EID-CT are higher spatial resolution, electronic noise reduction, higher contrast-to-noise ratio, improved radiation dose efficiency, and intrinsic spectral imaging. Successful implementation into clinical practice requires adaptations in CT protocols. In this review, we summarize the basic principles of PCD-CT and technical scanning factors followed by a discussion of its clinical benefits in pediatric pulmonary and cardiovascular imaging.

Multi-institutional Protocol Guidance for Pediatric Photon-counting CT.

Performing CT in children comes with unique challenges such as greater degrees of patient motion, smaller and densely packed anatomy, and potential risks of radiation exposure. The technical advancements of photon-counting detector (PCD) CT enable decreased radiation dose and noise, as well as increased spatial and contrast resolution across all ages, compared with conventional energy-integrating detector CT. It is therefore valuable to review the relevant technical aspects and principles specific to protocol development on the new PCD CT platform to realize the potential benefits for this population. The purpose of this article, based on multi-institutional clinical and research experience from pediatric radiologists and medical physicists, is to provide protocol guidance for use of PCD CT in the imaging of pediatric patients.

Size specific dose estimation in pediatric CT: preliminary study and conversion factors.

The objective of this paper is to compare the differences between volumetric CT dose index (CTDIVOL) and size-specific dose estimate (SSDEWED) based on water equivalent diameter (WED) in radiation dose measurement, and explore a new method for fast calculation of SSDEWED. The imaging data of 1238 cases of head, 1152 cases of chest and 976 cases of abdominopelvic were analyzed retrospectively, and they were divided into five age groups: ≤ 0.5, 0.5~≤ 1, 1~≤ 5, 5~≤ 10 and 10~≤ 15years according to age. The area of interest (AR), CT value (CTR), lateral diameter (LAT) and anteroposterior diameter (AP) of the median cross-sectional image of the standard scanning range and the SSDEWED were manually calculated, and a t-test was used to compare the differences between CTDIVOL and SSDEWED in different age groups. Pearson analyzed the correlations between DE and age, DE and WED, f and age, and counted the means of conversion factors in each age group, and analyze the error ratios between SSDE calculated based on the mean age group conversion factors and actual measured SSDE. The CTDIVOL in head was (9.41±1.42) mGy and the SSDEWED was (8.25±0.70) mGy: the difference was statistically significant (t=55.04, P<0.001); the CTDIVOL of chest was (2.68±0.91) mGy and the SSDEWED was (5.16±1.16) mGy, with a statistically significant difference (t=-218.78, P<0.001); the CTDIVOL of abdominopelvic was (3.09±1.58) mGy and the SSDEWED was (5.89±2.19) mGy: the difference was also statistically significant (t=-112.28, P<0.001). The CTDIVOL was larger than the SSDEWED in the head except for the ≤ 0.5year subgroup, and CTDIVOL was smaller than SSDEWED within each subgroup in chest and abdominopelvic. There were strong negative correlations between f and age (head: r=-0.81; chest: r=-0.89; abdominopelvic: r=-0.86; P<0.001). The mean values of f at each examination region were 0.81~1.01 for head, 1.65~2.34 for chest and 1.71~2.35 for abdominopelvic region. The SSDEWED could be accurately estimated using the mean f of each age subgroup. SSDEWED can more accurately measure the radiation dose of children. For children of different ages and examination regions, the SSDEWED conversion factors based on age subgroup can be quickly adjusted and improve the accuracy of radiation dose estimation.

Universal 120-kV Dual-Source Ultra-High Pitch Protocol on the Photon-Counting CT System for Pediatric Abdomen of All Sizes: A Phantom Investigation Comparing With Energy-Integrating CT.

The purpose of this study is to determine if a universal 120-kV ultra-high pitch and virtual monoenergetic images (VMIs) protocol on the photon-counting computed tomography (PCCT) system can provide sufficient image quality for pediatric abdominal imaging, regardless of size, compared with protocols using a size-dependent kV and dual-source flash mode on the energy-integrating CT (EICT) system. One solid water insert and 3 iodine (2, 5, 10 mg I/mL) inserts were attached or inserted into phantoms of variable sizes, simulating the abdomens of a newborn, 5-year-old, 10-year-old, and adult-sized pediatric patients. Each phantom setting was scanned on an EICT using clinical size-specific kV dual-source protocols with a pitch of 3.0. The scans were performed with fixed scanning parameters, and the CTDI vol values of full dose were 0.30, 0.71, 1.05, and 7.40 mGy for newborn to adult size, respectively. In addition, half dose scans were acquired on EICT. Each phantom was then scanned on a PCCT (Siemens Alpha) using a universal 120-kV protocol with the same full dose and half dose as determined above on the EICT scanner. All other parameters matched to EICT settings. Virtual monoenergetic images were generated from PCCT scans between 40 and 80 keV with a 5-keV interval. Image quality metrics were compared between PCCT VMIs and EICT, including image noise (measured as standard deviation of solid water), contrast-to-noise ratio (CNR) (measured at iodine inserts with solid water as background), and noise power spectrum (measured in uniform phantom regions). Noise at a PCCT VMI of 70 keV (7.0 ± 0.6 HU for newborn, 14.7 ± 1.6 HU for adult) is comparable ( P > 0.05, t test) or significantly lower ( P < 0.05, t test) compared with EICT (7.8 ± 0.8 HU for newborn, 15.3 ± 1.5 HU for adult). Iodine CNR from PCCT VMI at 50 keV (50.8 ± 8.4 for newborn, 27.3 ± 2.8 for adult) is comparable ( P > 0.05, t test) or significantly higher ( P < 0.05, t test) to the corresponding EICT measurements (57.5 ± 6.7 for newborn, 13.8 ± 1.7 for adult). The noise power spectrum curve shape of PCCT VMI is similar to EICT, despite PCCT VMI exhibiting higher noise at low keV levels. The universal PCCT 120 kV with ultra-high pitch and postprocessed VMIs demonstrated equivalent or improved performance in noise (70 keV) and iodine CNR (50 keV) for pediatric abdominal CT, compared with size-specific kV images on the EICT.

Comparison of Image Quality and Radiation Dose in Pediatric Temporal Bone CT Using Photon-Counting Detector CT and Energy-Integrating Detector CT.

Currently, there is a lack of research directly comparing photon-counting detector CT (PCD-CT) and energy-integrating detector CT (EID-CT) in pediatric temporal bone CT imaging. The purpose of this study was to compare the image quality and radiation dose of temporal bone CT scans in pediatric patients acquired with PCD-CT and EID-CT. The retrospective study included a total of 110 pediatric temporal bone CT scans (PCD-CT, n = 52; EID-CT, n = 58). Two independent readers evaluated the spatial resolution of 4 anatomic structures (tympanic membrane, incudostapedial joint, stapedial crura, and cochlear modiolus) and overall image quality by using a 4-point scale. Interreader agreement was assessed. Dose-length product for each CT was compared, and subgroup analyses were performed based on age (younger than 3 years, 3-5 years, 6-11 years, and 12 years and above). PCD-CT demonstrated statistically significantly higher scores than EID-CT for all items (tympanic membrane, 2.9 versus 2.4; incudostapedial joint, 3.6 versus 2.6; stapedial crura, 3.2 versus 2.4; cochlear modiolus, 3.4 versus 2.8; overall image quality, 3.6 versus 2.8; P < .05). Interreader agreement ranged from good to excellent (interclass correlation coefficients, 0.6-0.81). PCD-CT exhibited a 43% dose reduction compared with EID-CT, with a particularly substantial reduction of over 70% in the subgroups of children younger than 6 years. PCD temporal bone CT achieves significantly superior imaging quality at a lower radiation dose compared with EID-CT.

Beyond the AJR: Deep Learning Shows Promise in the Detection of Retinal Hemorrhage on Pediatric Head CT.

Beyond the AJR: Deep Learning Shows Promise in the Detection of Retinal Hemorrhage on Pediatric Head CT.

Commissioning and clinical implementation of an independent dose calculation system for scanned proton beams.

Experimental patient-specific QA (PSQA) is a time and resource-intensive process, with a poor sensitivity in detecting errors. Radiation therapy facilities aim to substitute it by means of independent dose calculation (IDC) in combination with a comprehensive beam delivery QA program. This paper reports on the commissioning of the IDC software tool myQAiON (IBA Dosimetry) for proton therapy and its clinical implementation at the MedAustron Ion Therapy Center. The IDC commissioning work included the validation of the beam model, the implementation and validation of clinical CT protocols, and the evaluation of patient treatment data. Dose difference maps, gamma index distributions, and pass rates (GPR) have been reviewed. The performance of the IDC tool has been assessed and clinical workflows, simulation settings, and GPR tolerances have been defined. Beam model validation showed agreement of ranges within±0.2mm, Bragg-Peak widths within±0.1mm, and spot sizes at various air gaps within±5% compared to physical measurements. Simulated dose in 2D reference fields deviated by-0.3%±0.5%, while 3D dose distributions differed by 1.8% on average to measurements. Validation of the CT calibration resulted in systematic differences of 2.0% between IDC and experimental data for tissue like samples. GPRs of 99.4±0.6% were found for head, head and neck, and pediatric CT protocols on a 2%/2mm gamma criterion. GPRs for the adult abdomen protocol were at 98.9% on average with 3%/3mm. Root causes of GPR outliers, for example, implants were identified and evaluated. IDC has been successfully commissioned and integrated into the MedAustron clinical workflow for protons in 2021. IDC has been stepwise and safely substituting experimental PSQA since February 2021. The initial reduction of proton experimental PSQA was about 25% and reached up to 90% after 1 year.

Age Encoded Adversarial Learning for Pediatric CT Segmentation.

Organ segmentation from CT images is critical in the early diagnosis of diseases, progress monitoring, pre-operative planning, radiation therapy planning, and CT dose estimation. However, data limitation remains one of the main challenges in medical image segmentation tasks. This challenge is particularly huge in pediatric CT segmentation due to children's heightened sensitivity to radiation. In order to address this issue, we propose a novel segmentation framework with a built-in auxiliary classifier generative adversarial network (ACGAN) that conditions age, simultaneously generating additional features during training. The proposed conditional feature generation segmentation network (CFG-SegNet) was trained on a single loss function and used 2.5D segmentation batches. Our experiment was performed on a dataset with 359 subjects (180 male and 179 female) aged from 5 days to 16 years and a mean age of 7 years. CFG-SegNet achieved an average segmentation accuracy of 0.681 dice similarity coefficient (DSC) on the prostate, 0.619 DSC on the uterus, 0.912 DSC on the liver, and 0.832 DSC on the heart with four-fold cross-validation. We compared the segmentation accuracy of our proposed method with previously published U-Net results, and our network improved the segmentation accuracy by 2.7%, 2.6%, 2.8%, and 3.4% for the prostate, uterus, liver, and heart, respectively. The results indicate that our high-performing segmentation framework can more precisely segment organs when limited training images are available.

Assessment of effective dose and cancer risk for pediatric chest and pelvis CT procedures in the central region of Saudi Arabia

BackgroundCT accounts for the highest radiation dose among various imaging modalities. Children are more susceptible to the harmful effects of radiation because of their higher cell-division rate and the likelihood of longer lifespans. Therefore, it is important to monitor pediatric CT doses to minimize their potential risks. AimThe objective of this study was to evaluate the radiation doses received by pediatrics undergoing trunk CT procedures and to estimate the associated cancer risk. MethodsA total of 255 pediatric patients who underwent chest (92 cases), abdomen & pelvis (133 cases), and chest-abdomen-pelvis (CAP) scans (30 cases) from hospitals within the central region of Saudi Arabia were categorized into four age groups: <1 year, 1–5 years, 6–10 years, and 11–15 years. The averages and ranges of DLP and CTDIvol from each procedure were measured and compared with international reports. The effective dose and cancer risk from each procedure were also reported. ResultsThe mean and range DLP (mGy.cm) for chest, abdomen & pelvis, and CAP examinations were found to be 131.5 (13.8–375.5), 244 (10.5–1353), and 94.2 (23.5–239), respectively. The mean and range CTDIvol (mGy) for chest, abdomen & pelvis, and CAP examinations were found to be 5.5 (1–33.8), 5.5 (0.9–18.6), and 3.6 (1.3–24.8) in order. The effective dose (mSv) and associated cancer risk (case/10,000 cases) for chest, abdomen & pelvis, and CAP ranges between (2.31–3.37; 1.27–1.85), (4.19–6.89; 2.30–3.78), and (1.89–3.58; 1.04–1.97), respectively. ConclusionEstimations of effective doses and cancer risk were conducted for pediatric patients aged <1 through 15 years who underwent chest, abdomen & pelvis, and CAP procedures. The documented dose levels in this study were relatively elevated compared to similar reports, revealing substantial variations even within the same procedure and age group category. Therefore, prioritizing dose optimization practices becomes crucial to mitigate potential radiation-induced cancer risks.