Pediatric Computed Tomography Scans Research Articles

Future Perspective for Radiation Dose Reduction techniques in Computed Tomography - A Study

The Computed Tomography (CT) image quality is determining by appropriate radiation dose in CT examination. Increases of the radiation dose become dangerous for our health such as induces of cancer, skin injuries, heritable mutations, reddening, burn the skins, etc. Therefore, the dose management study in the CT scanning procedure is one of the most important factors. This research article focuses on the use of the dose effectively in pediatric CT and cardiac CT scan procedures. Besides, the paper comprises dose hunt-down, auditing the scanner utilization, patient safety for the hospital association. This research article discusses radiation dose reduction techniques for effective dose in the view of future perspective in CT scan. This research article suggesting an appropriate technique to reduce the dose effectively in CT images during scanning. The effective dose test was conducted after reviews and ideas from future perspective designs.

Evaluation of age-based radiation dose in paediatric patients received from head CT examination at a tertiary hospital, Nigeria

Paediatric computed tomography (CT) imaging though requested less than adult CT but has shown remarkable growth with raising concerns of increased radiation risk to the paediatric population. This study aims to evaluate age-based radiation dose from paediatric head CT scans at a single centre in Nigeria. This study evaluated 233 paediatric aged 0–15 years and were classified into four age groups; Group 1 (≤1 year), Group 2 (2–5 years), Group 3 (6–10 years) and Group 4 (11–15 years). Patient dose and related scanning protocol data were retrospectively retrieved from the CT scanner. The local dose values were calculated as 25th and 75th percentiles of the distribution of the volume CT dose index (CTDIvol), dose length product (DLP) and effective dose per age-group. These values were compared with the recommended international diagnostic reference levels (DRLs). The estimated dose values were within limits for the youngest age group (≤1 year old) but showed a clear trend towards higher doses for other age groups as compared with DRLs. The relative difference for CTDIvol and DLP were ranged between 0‒45% and 8–64%, respectively. The largest difference in DRLs was seen in Group 3 and 4. The dose values were increased with the increasing age; Group 1 received the lowest doses (20 mGy, 345 mGy.cm, and 3.2 mSv) and Group 4 received the highest doses (61 mGy, 1497 mGy.cm, and 4.4 mSv). The local doses were substantially higher than the international DRLs values except for age group ≤1 year, demonstrating a necessity for dose optimization and modification of current acquisition technique towards the reduction of radiation dose among paediatric population.

Pediatric computed tomography scan parameters and radiation dose revisited for pediatric imaging team

Pediatric computed tomography scan parameters and radiation dose revisited for pediatric imaging team

EVALUATION OF IRRADIATION DOSES DELIVERED TO PATIENTS IN COMPUTED TOMOGRAPHY EXAMINATIONS IN 10 RADIOLOGY DEPARTMENTS IN DOUALA-CAMEROON.

Computed tomography (CT) scan is currently the most irradiating radio diagnostic procedure for the patients. The effective dose delivered by a CT-scan exploration corresponds to 1-20years of natural irradiation of an individual. Hence, there is need to evaluate this medical exposure, in order to provide indicators and propose guidelines for its daily practice. The purpose of this work was to assess patient exposure levels due to CT-scan exams and propose a local diagnostic reference levels for the most common CT examinations performed in the radiology units of Douala/Cameroon. Data from 1775 CT scans, amongst which 10 different types of common CT examinations on adults and children, were collected, of which 1378 were adult CT scans and 397 were pediatric CT scans. The dose-length product (DLP) values in the adult population for head, abdomen-pelvic and lumber spine CT scans were high as compared to the Institute for Radiological Protection and Nuclear Safety recommendations and previous local DRL with an increase of 36, 15 and 23%, respectively. A general decrease of the DLP for CT-scans examinations in the pediatric population was observed.

AGE-CONDITIONED SYNTHESIS OF PEDIATRIC COMPUTED TOMOGRAPHY WITH AUXILIARY CLASSIFIER GENERATIVE ADVERSARIAL NETWORKS.

Deep learning is a popular and powerful tool in computed tomography (CT) image processing such as organ segmentation, but its requirement of large training datasets remains a challenge. Even though there is a large anatomical variability for children during their growth, the training datasets for pediatric CT scans are especially hard to obtain due to risks of radiation to children. In this paper, we propose a method to conditionally synthesize realistic pediatric CT images using a new auxiliary classifier generative adversarial network (ACGAN) architecture by taking age information into account. The proposed network generated age-conditioned high-resolution CT images to enrich pediatric training datasets.

Radiation exposure from computerized tomography and risk of childhood leukemia: Finnish register-based case-control study of childhood leukemia (FRECCLE).

The only well-established risk factors for childhood leukemia are high-dose ionizing radiation and Down syndrome. Computerized tomography is a common source of low-dose radiation. In this study, we examined the magnitude of the risk of childhood leukemia after pediatric computed tomography examinations. We evaluated the association of computed tomography scans with risk of childhood leukemia in a nationwide register-based case-control study. Cases (n=1,093) were identified from the population-based Finnish Cancer Registry and three controls, matched by gender and age, were randomly selected for each case from the Population Registry. Information was also obtained on birth weight, maternal smoking, parental socioeconomic status and background gamma radiation. Data on computed tomography scans were collected from the ten largest hospitals in Finland, covering approximately 87% of all pediatric computed tomography scans. Red bone marrow doses were estimated with NCICT dose calculation software. The data were analyzed using exact conditional logistic regression analysis. A total of 15 cases (1.4%) and ten controls (0.3%) had undergone one or more computed tomography scans, excluding a 2-year latency period. For one or more computed tomography scans, we observed an odds ratio of 2.82 (95% confidence interval: 1.05 – 7.56). Cumulative red bone marrow dose from computed tomography scans showed an excess odds ratio of 0.13 (95% confidence interval: 0.02 – 0.26) per mGy. Our results are consistent with the notion that even low doses of ionizing radiation observably increase the risk of childhood leukemia. However, the observed risk estimates are somewhat higher than those in earlier studies, probably due to random error, although unknown predisposing factors cannot be ruled out.

Obesity is associated with a reduced odds for blunt intra-abdominal injuries in children

ObjectivesChildren with obesity may possess unique injury characteristics that may affect their emergency care. To better understand this relationship, we investigated the association of obesity in pediatric trauma patients and intra-abdominal injuries (IAIs) and routinely utilized emergency department (ED) diagnostic procedures (computed tomography (CT) scans and ultrasound (US) examinations). MethodsThis secondary data analysis utilized Pediatric Emergency Care Applied Research Network (PECARN) data from 2007 to 2010. Since height data were not available, children (2–17 years) with obesity were defined using weight-for-age percentiles. Non-parametric testing determined potential confounders. Adjusted odds ratios (aOR) were calculated using binary logistic regression for weight status and IAIs and diagnostic procedures. ResultsThere were 3846 patients with actual weight recorded: 3301 (85.8%) children without obesity and 545 (14.2%) with obesity. Children with obesity had decreased odds for IAI after adjusting for race, mechanical force injury (MFI) type, vomiting, and abdominal wall trauma (adjusted odds ratio (aOR)=0.58 (95% CI 0.35–0.97); p-value=0.04). Patients with obesity had reduced odds for a CT examination. No association was found between obesity status and US utilization. African-American patients had decreased odds for IAIs, CT scans and US examinations after adjustment which could be related to MFI type. ConclusionsObesity appears to reduce the odds for pediatric IAIs and CT scans, but not for US examinations. Selection bias is possible due to injury severity and missing or excluded weight data. Further research is needed in other pediatric populations with obesity and blunt injuries.

Size-specific dose estimations for pediatric chest, abdomen/pelvis and head CT scans with the use of GATE

PurposeThe purpose of this study is to create an organ dose database for pediatric individuals undergoing chest, abdomen/pelvis, and head computed tomography (CT) examinations, and to report the differences in absorbed organ doses, when anatomical differences exist for pediatric patients. MethodsThe GATE Monte Carlo (MC) toolkit was used to model the GE BrightSpeed Elite CT model. The simulated scanner model was validated with the standard Computed Tomography Dose Index (CTDI) head phantom. Twelve computational models (2.1–14 years old) were used. First, contributions to effective dose and absorbed doses per CTDIvol and per 100 mAs were estimated for all organs. Then, doses per CTDIvol were correlated with patient model weight for the organs inside the scan range for chest and abdomen/pelvis protocols. Finally, effective doses per dose-length product (DLP) were estimated and compared with the conventional conversion k-factors. ResultsThe system was validated against experimental CTDIw measurements. The doses per CTDIvol and per 100 mAs for selected organs were estimated. The magnitude of the dependency between the dose and the anatomical characteristics was calculated with the coefficient of determination at 0.5–0.7 for the internal scan organs for chest and abdomen/pelvis protocols. Finally, effective doses per DLP were compared with already published data, showing discrepancies between 13 and 29% and were correlated strongly with the total weight (R2 > 0.8) for the chest and abdomen protocols. ConclusionsBig differences in absorbed doses are reported even for patients of similar age or same gender, when anatomical differences exist on internal organs of the body.

Comparative study of intravenous and oral midazolam in pediatric CT scans for non CNS pathology

Introduction: There has been a dramatic increase in the use of computed tomography (CT) scan to diagnose conditions and to monitor treatment in the pediatric setting. Infants and children require sedation during procedure to maintain a motionless state to ensure high quality imaging. The target sedation depth required depends on imaging procedure and individual patient characteristics. CT scans with modern multislice scanners do rapid image acquisition and procedure may require minimal sedation. But some children need to be asleep to tolerate the study scan. Procedures may be rescheduled and repeated if the movement is excessive which leads to additional radiation burden which leads to increasing the cost of the procedure and patient stress. Careful planning of sedation is important in such scenarios.1 Many drug regimens have been recommended to achieve satisfactory sedation for such painless procedure. Most of these medications can be administered through various routes and selecting the drug varies on the procedure, level of pain, optimum depth of sedation required and the patient’s condition.2 Midazolam has been widely used as a sedative in children for a long time.3 This study compares the effect of intravenous and oral Midazolam in paediatric age group with respect to degree of sedation levels achieved, and the need for a rescue dose for non CNS Computed Tomography scans. Materials and Methods: In this prospective study, oral Midazolam verses IV Midazolam was studied for sedation in paediatric patients of 2 to 6 years of age for non CNS CT scan. 0.5mg/kg of oral Midazolam and 0.01mg/kg of IV Midazolam was used. 1mg/kg Propofol used as the rescue drug and 0.5mg/kg subsequently till the desired sedation score was achieved. 70 patients were divided into 2 groups of 35in each group. 1: Group A received oral 0.5 mg/kg body weight Midazolam 20 minutes prior to the scan (a maximum dose of 10 mg); 2: Group B received IV 0.01mg/kg body weight Midazolam 5 minute

Factors Affecting Emergency Department Computed Tomography Use in Children

BackgroundVariability in computed tomography (CT) use during pediatric emergency department (ED) visits has been reported. Our objective was to identify patient and hospital characteristics associated with CT use during pediatric ED visits. MethodsPatients <18 y treated and released from EDs in the 2006-2012 Nationwide Emergency Department Sample were included. Associations were evaluated between pediatric CT scan rate and patient/hospital factors using logistic mixed effects models. Independent predictors of being a high outlier (having a pediatric CT scan rate in the top 10%) were also evaluated using logistic regression models. ResultsThere were 1543 EDs and 20,703,273 visits included. CT scans were prescribed in 4.7% of pediatric ED visits; the highest 10% of EDs prescribed CT scans in >7.63% of all pediatric visits. In multivariable analysis, older age, male gender, private insurance, higher zip code level median income, and higher injury severity were all associated with an increased probability of receiving a CT scan (all P < 0.001). The chance of receiving a CT scan also varied by diagnosis and was independently associated with geographic location and annual pediatric ED volume. Rates of CT use increased with increasing pediatric volume up to approximately 5400 annual pediatric visits, and then decreased with volume >5400 annual visits. ConclusionsSeveral patient-level and ED-level characteristics, including annual pediatric volume, are associated with the probability of a child having a CT scan during an ED visit. Future work should focus on determining drivers behind these associations to develop intervention strategies to decrease pediatric CT use.

Liver segmentation from low-radiation-dose pediatric computed tomography using patient-specific, statistical modeling.

The pediatric computed tomography (CT) volume is acquired at a low dose because radiation is harmful to young children. Consequently, the pediatric CT volume has lower signal-to-noise ratio, which makes organ segmentation difficult. In this paper, we propose a liver segmentation algorithm for pediatric CT scan using a patient-specific level set distribution model (LSDM). The patient-specific LSDM was constructed using a conditional LSDM (C-LSDM) conditioned on age. Furthermore, a patient-specific probabilistic atlas (PA) was generated using the model, which became a priori to the maximum a posteriori-based segmentation. The patient-specific PA generation by the C-LSDM using kernel density estimation was quicker than the conventional PA generation method using random numbers, and also, it was more accurate as it did not include any approximations. The liver segmentation algorithm was tested on 42 CT volumes of children aged between 2weeks and 7years. In the proposed method, the calculation time of the PA was about 9s for the single Gaussian method, while it was 337s for the conventional PA generation method using random numbers. Furthermore, using the kernel density estimation, median and 25%/75% tile of the generalized Dice similarity index between the PA and the correct liver region were found to be 0.3443 and 0.3191/0.3595. The Dice similarity index in the segmentation was 0.8821 and 0.8545/0.9085, which are higher than those obtained by the conventional method, and requires lower computational cost. We proposed a method to quickly and accurately generate a PA, combined with C-LSDM using kernel density estimation, which enabled efficient calculation and improved segmentation accuracy.

Assessment of compliance levels of effective doses in pediatric CT

Introduction: Computed tomography (CT) is a medical imaging modality that produces 3-D cross-sectional images of tissues using several X-ray projections at different angles. Since its introduction in the 1970s, CT usage has been on the increase for both adults and pediatrics. A major challenge of this modality is the high doses of radiation exposure to patients, especially in pediatrics, who are more radiosensitive compared to adults. Hence, the need to ensure that radiation safety standards are adhered to. This will go a long way in reducing the adverse effects of radiation. The aim of this study was to assess the level of compliance to international dose reference levels (DRLs) in terms of effective doses in pediatric CT scans conducted in three Iraqi hospitals. Materials and Methods: CT brain and abdomen/pelvis examinations were conducted for pediatric patients aged between few months and 15 years in three Iraqi hospitals (Al Wasiti, Neuroscience and Al Omara). All scans were performed on a Somatom Sensation® 16 multidetector CT (MDCT) scanner with a Straton® X-ray tube (Siemens, Erlangen, Germany) utilising automatic tube current modulation (CARE Dose4DTM; Siemens, Erlangen, Germany). Volumetric CT dose index (CTDIvol) and dose length product (DLP) were collected for 180 patients (60 in each hospital). Afterwards, their effective doses were estimated from DLP values and compared with international DRLs. Results: Brain CT: The DLP values obtained for Al Wasiti, Neuroscience and Al Omara hospitals were in the range; 789-918.8 mGy.cm, 833-874.6 mGy.cm and 627.6-810 mGy.cm respectively, while their corresponding effective doses were in the range; 1.8-2.09 mSv, 1.9- 2.06 mSv and 1.43-1.83 mSv. Abdomen/Pelvis: The DLP values obtained for Al Wasiti, Neuroscience and Al Omara hospitals were in the range; 392.9-425.8 mGy.cm, 355-395 mGy.cm and 314.8-383.6 mGy.cm respectively, while their corresponding effective doses were in the range; 6.65-7.22 mSv, 6- 6.7 mSv and 5.34-6.51 mSv. Using the International Commission on Radiological Protection (ICRP) publication 103 as basis for assessing compliance level, for brain CT we observe slightly higher values in Al Wasiti and Neuroscience hospitals while Al Omara was similar to the international DRLs. However, for abdomen/pelvis CT examinations, the effective doses in all three hospitals were within the acceptable limits of international DRLs. Conclusion: This study has shown an encouraging level of compliance towards adequate radiation protection management in pediatric CT examinations among the three hospitals. Although, the best compliance level was observed in Al Omara hospital. Regular monitoring should be enforced to ensure that CT doses delivered to pediatric patients are as low as reasonably achievable without compromising diagnostic quality.

Extent of tube-current reduction using sinogram affirmed iterative reconstruction in pediatric computed tomography: phantom study.

Iterative image reconstruction techniques can produce diagnostic-quality computed tomography (CT) images with lower radiation dose. To quantify the reduction in x-ray tube-current setting and optimize pediatric CT scans using different strengths of an iterative reconstruction technique. The head, chest and abdomen regions of an anthropomorphic phantom representing a 5-year-old patient were scanned using standard CT protocols. Images were reconstructed using filtered back projection and different strengths of a sinogram affirmed iterative reconstruction technique. Repeated measurements of contrast-to-noise ratios in the lungs, bone and soft-tissue regions of the phantom were carried out. Maximum increase in contrast-to-noise ratio with iterative reconstruction strength was identified and a tube-current reduction factor was calculated. Head scans were repeated with reduced tube current and compared to filtered back projection images. Iterative reconstruction strength of 3 for head and chest images and 4 for abdomen images were optimum, resulting in contrast-to-noise ratio increase of about 50%. A tube-current reduction factor of 1.2 for head images was calculated. Images of the head acquired using reduced tube-current showed similar contrast-to-noise ratio as images form filtered back projection with full tube current. Optimum strength of iterative reconstruction technique has been identified for head, chest and abdomen images. Reductions in tube current of 20%, resulting in similar radiation dose reduction, have been established.

188 Impact of Adult Level 1 Trauma Designation on the Timeliness of Pediatric Emergency Department Computed Tomography Scans

Timeliness in the provision of medical care is an essential aspect of patient safety and health care quality. Given the unpredictable nature of the emergency department (ED) with regards to variation in disease acuity and patient volume, it is essential to gather crucial information in a prompt fashion to aid medical decisionmaking and patient disposition. The adult emergency department of our institution was verified as a Level 1 Trauma Center by the American College of Surgeons in December 2015, 24 years after our pediatric emergency department was recognized as a Level 1 Trauma Center. One of the metrics used as an operational benchmark in the ED is imaging interval (time from order of an imaging test to the availability of results). There is a single computed tomography (CT) scanner located in the emergency department, which is utilized by both the adult and pediatric sections. With an anticipated increase in the adult ED patient volume following its new status, we sought to assess the impact of adult Level 1 Trauma designation on the timeliness of pediatric non-trauma CT scans in an emergency department. Retrospective chart review of patients in the pediatric emergency department who had CT scans was performed. We compared CT scan orders of patients over the same 6-month period prior to and after the adult ED Level 1 Trauma verification, and assessed the time from order to completion of CT scans. The months with historically highest trauma volumes were chosen. All pediatric trauma activations were excluded, as well as duplicate orders and scans performed during EMR downtime. Unpaired student t-tests and Chi-squared tests were used for statistical analyses. There were 218 consecutive CT scans analyzed in 2015, and 193 consecutive CT scans in the same time frame in 2016. About half of the CT scans in both years were head imaging studies, and more males were scanned compared to females. The average time for CT completion prior to adult ED Level 1 verification was 39.5 minutes, compared to 55.5 minutes in the same time frame the next year (p<0.0001). Also, the proportion of children receiving CT scans within 60 minutes from order decreased from 81% in 2015 to 65% in 2016. (p=0.0002; 95% CI 7.4 - 24.4). The new designation of adult Level 1 trauma status in our ED was associated with a significant delay (by more than 40%) in performance of non-trauma pediatric CT scans, and decrease in the likelihood of children receiving CT scans within 60 minutes. These findings may have significant clinical and economic ramifications for pediatric patients and hospitals, and represent the potential "collateral damage" of an institution receiving an upgrade of their adult trauma center to Level 1 status.

VALIDATION OF MONTE CARLO DOSE CALCULATION FOR PAEDIATRIC CT EXAMINATIONS USING TUBE CURRENT MODULATION BASED ON IN-PHANTOM DOSIMETRY.

The aim of this study is to estimate tube current modulation (TCM) profiles in paediatric computed tomography (CT) examinations with a TCM scheme (Volume-EC) and evaluate the estimation accuracy of TCM profiles. Another aim is to validate organ doses calculated using Monte Carlo-based CT dosimetry software and estimated TCM profiles by comparing them with those measured using 5-year-old and 10-year-old anthropomorphic phantoms and radio-photoluminescence glass dosemeters. Dose calculations were performed by inputting detailed descriptions of a CT scanner, scan parameters and CT images of the phantoms into the software. Organ doses were evaluated from the calculated dose distribution images. Average relative differences (RDs) between the estimated and actual TCM profiles ranged from -3.6 to 5.6%. RDs between the calculated and measured organ doses ranged from -4.2 to 13.0% and -18.1 to 4.9% for 5-year-old and 10-year-old phantoms, respectively. These results validate dose calculations for paediatric CT scans using TCM.

Radiation Exposure From Pediatric CT Scans and Subsequent Cancer Risk in the Netherlands.

Computed tomography (CT), a strong diagnostic tool, delivers higher radiation doses than most imaging modalities. As CT use has increased rapidly, radiation protection is important, particularly among children. We evaluate leukemia and brain tumor risk following exposure to low-dose ionizing radiation from CT scans in childhood. For a nationwide retrospective cohort of 168 394 children who received one or more CT scans in a Dutch hospital between 1979 and 2012 who were younger than age 18 years, we obtained cancer incidence, vital status, and confounder information by record linkage with external registries. Standardized incidence ratios were calculated using cancer incidence rates from the general Dutch population. Excess relative risks (ERRs) per 100 mGy organ dose were calculated with Poisson regression. All statistical tests were two-sided. Standardized incidence ratios were elevated for all cancer sites. Mean cumulative bone marrow doses were 9.5 mGy at the end of follow-up, and leukemia risk (excluding myelodysplastic syndrome) was not associated with cumulative bone marrow dose (44 cases). Cumulative brain dose was on average 38.5 mGy and was statistically significantly associated with risk for malignant and nonmalignant brain tumors combined (ERR/100 mGy: 0.86, 95% confidence interval = 0.20 to 2.22, P = .002, 84 cases). Excluding tuberous sclerosis complex patients did not substantially change the risk. We found evidence that CT-related radiation exposure increases brain tumor risk. No association was observed for leukemia. Compared with the general population, incidence of brain tumors was higher in the cohort of children with CT scans, requiring cautious interpretation of the findings.

Radiation exposure from computerized tomography and risk of childhood leukemia: Finnish register-based case-control study of childhood leukemia (FRECCLE).

The only well-established risk factors for childhood leukemia are high-dose ionizing radiation and Down syndrome. Computerized tomography is a common source of low-dose radiation. In this study, we examined the magnitude of the risk of childhood leukemia after pediatric computed tomography examinations. We evaluated the association of computed tomography scans with risk of childhood leukemia in a nationwide register-based case-control study. Cases (n=1,093) were identified from the population-based Finnish Cancer Registry and three controls, matched by gender and age, were randomly selected for each case from the Population Registry. Information was also obtained on birth weight, maternal smoking, parental socioeconomic status and background gamma radiation. Data on computed tomography scans were collected from the ten largest hospitals in Finland, covering approximately 87% of all pediatric computed tomography scans. Red bone marrow doses were estimated with NCICT dose calculation software. The data were analyzed using exact conditional logistic regression analysis. A total of 15 cases (1.4%) and ten controls (0.3%) had undergone one or more computed tomography scans, excluding a 2-year latency period. For one or more computed tomography scans, we observed an odds ratio of 2.82 (95% confidence interval: 1.05 – 7.56). Cumulative red bone marrow dose from computed tomography scans showed an excess odds ratio of 0.13 (95% confidence interval: 0.02 – 0.26) per mGy. Our results are consistent with the notion that even low doses of ionizing radiation observably increase the risk of childhood leukemia. However, the observed risk estimates are somewhat higher than those in earlier studies, probably due to random error, although unknown predisposing factors cannot be ruled out.

Optimization of dose and image quality using self-produced phantom with various diameters in pediatric abdominal CT scan

Computed tomography (CT) provides various advantages; however, the radiation exposure dose is high. In a pediatric CT scan, a reduction of the exposure dose would lead to a larger noise and lower image quality. Therefore, we investigated the optimization between the dose and image quality in a pediatric CT scan. We used a 128-channel CT device and self-produced computed-tomography-dose-index (CTDI) phantoms with various diameters (12, 16, 20, and 24 cm). Various exposure conditions were considered by varying the tube voltage and tube current. Evaluation parameters were the weighted CTDI (CTDIw), contrast, noise, and contrast-to-noise-ratio (CNR). In addition, we calculated the contrast-to-noise ratio dose (CNRD) to optimize the dose and image quality. The measured CTDIw increased with the tube voltage and tube current. The obtained contrast and noise values decreased, while the CNR was almost unaffected with the increase of the tube voltage. With the increase of the tube current, the contrast was not considerably affected, the noise decreased, and the CNR increased. The highest CNRD was obtained for the lowest tube voltage and tube current. Therefore, an optimized image quality was obtained using the minimum radiation exposure dose with a high CNRD in a pediatric abdomen CT scan.

Study on Feasibility for Artificial Intelligence (AI) Noise Reduction Algorithm with Various Parameters in Pediatric Abdominal Radio-Magnetic Computed Tomography (CT)

The importance of radiation-based images has been increasing due to their ability to provide rapid diagnosis and facilitate treatment of lesions. Among them, the frequency of examination using computed tomography(CT) has been increasing because of this technique’s fast examination time and high diagnostic power. However, although the criteria for screening have been presented based on many previous studies on the CT exposure dose for adults, the criteria for children remain inadequate. Especially, relaxing the conditions to reduce the exposure dose of CT will lead to generation of noises. To address this problem, many noise removal algorithms have been developed. Among developed algorithms, a particularly strong interest has been focused on deep learning methods, which are a sort of artificial intelligence (AI)-based machine learning. Therefore, the present study aimed to develop a noise removal algorithm using the Gaussian Mixture Model (GMM), an AIbased deep learning method, and to apply the algorithm to pediatric abdominal CT so that to evaluate the usefulness of the approach. PMMA phantoms with different diameters of 12, 16, 20, 24, and 32 cm, which can express pediatric abdomen, were manufactured and used. To evaluate dose and image quality, the tube current was fixed to 200 mAs and the tube voltage was changed from 80 to 120, and 140 kVp; thereafter, the tube voltage was fixed to 120 kVp and the tube currents were changed from 50 to 100, 150, 200, and 250 mAs. According to the results, CTDIw showed a tendency to increase alongside with increases in the tube voltage and the tube currents, while noise decreased proportionally. In addition, the contrast decreased as the tube voltage increased, but was shown to be almost unrelated to the tube currents. Finally, the excellent CNRD result was measured in lowest exposure condition at 80 kVp and 50 mAs. Also, the average of CNRD with AI noise reduction algorithm was 1.6-4.2 times higher than before the application. In conclusion, the doses and characteristics of the pediatric abdominal CT scan according to various image acquisition conditions could be successfully identified and the efficiency of the AI noise removal algorithm developed in the present study was demonstrated.

Adaptive statistical iterative reconstruction use for radiation dose reduction in pediatric lower-extremity CT: impact on diagnostic image quality.

For the past several years, increased levels of imaging radiation and cumulative radiation to children has been a significant concern. Although several measures have been taken to reduce radiation dose during computed tomography (CT) scan, the newer dose reduction software adaptive statistical iterative reconstruction (ASIR) has been an effective technique in reducing radiation dose. To our knowledge, no studies are published that assess the effect of ASIR on extremity CT scans in children. To compare radiation dose, image noise, and subjective image quality in pediatric lower extremity CT scans acquired with and without ASIR. The study group consisted of 53 patients imaged on a CT scanner equipped with ASIR software. The control group consisted of 37 patients whose CT images were acquired without ASIR. Image noise, Computed Tomography Dose Index (CTDI) and dose length product (DLP) were measured. Two pediatric radiologists rated the studies in subjective categories: image sharpness, noise, diagnostic acceptability, and artifacts. The CTDI (p value = 0.0184) and DLP (p value <0.0002) were significantly decreased with the use of ASIR compared with non-ASIR studies. However, the subjective ratings for sharpness (p < 0.0001) and diagnostic acceptability of the ASIR images (p < 0.0128) were decreased compared with standard, non-ASIR CT studies. Adaptive statistical iterative reconstruction reduces radiation dose for lower extremity CTs in children, but at the expense of diagnostic imaging quality. Further studies are warranted to determine the specific utility of ASIR for pediatric musculoskeletal CT imaging.