CT is a commonly examination method in pediatric clinical practice.Formulating and popularizing low-dose pediatric CT scanning protocols and constructing a standard image quality evaluation system are the key directions of low-dose pediatric CT imaging.In recent years,domestic CT equipment achieved technological breakthroughs in hardware performance and image reconstruction algorithms,which could provide new paths for pediatric low-dose CT imaging in children combining with artificial intelligence technology.The current status of scanning protocols,the establishment of imaging quality evaluation system and the clinical promotion,as well as challenges of domestic CT in pediatric low-dose CT imaging were reviewed in this article.

Objective:To evaluate whether the reconstructed image on the basis of deep learning(DL)can improve the success rate and display quality of automatic segmentation of computed tomography(CT)with ultralow dose for chest of children on airway.Methods:The clinical data of 41 consecutive cases who adopted ultralow dose CT to underwent reexamination on chest at Beijing Children's Hospital,Capital Medical University from February 2020 to September 2020 were selected,whose average age was(4.43±1.61 years).The scan protocol of ultralow dose CT was(0.05 mGy).The reconstructed images included 6 groups,which were respectively filtered reflection projection(FBP)image with 0.625 mm thickness,50%adaptive iterative recombination(ASIR-V)images,100%ASIR-V images,low energy DL(DL-L),medium energy DL(DL-M),and high energy DL(DL-H).The automatically segmentation software was used to conduct automatically segmentation for airway,and the success rate of automatic segmentation was recorded.For images that were successful segmented,a 5-point scale was adopted to subjectively evaluate the displayed quality for airway(5 point is the best).In addition,the CT values and noise values of the images of 6 groups for airway were objectively measured.Results:The success rate of automatic segmentation of DL-H image was the highest(60.98%),and that of the 100%ASIR-V was the lowest(39.02%).The subjective score of DL-H image of the automatic segmentation was the highest(4.06±0.55)point,and that of 100%ASIR-V was the lowest(2.44±0.76)point.DL-H can display more fine and small airways.The noise values of objective measurement showed that both of DL-H and 100%ASIR-V had the lowest noise value,and there was no statistical difference in that between them.Conclusion:The use of high energy deep learning iterative reconstruction(DLIR)algorithm can improve the success rate and display effect of automatic segmentation of ultralow dose CT for chest of children on airway,and DLIR is contribute to improve the accuracy of automatic segmentation algorithm of artificial intelligence.

Objective:To evaluate whether the reconstructed image on the basis of deep learning(DL)can improve the success rate and display quality of automatic segmentation of computed tomography(CT)with ultralow dose for chest of children on airway.Methods:The clinical data of 41 consecutive cases who adopted ultralow dose CT to underwent reexamination on chest at Beijing Children's Hospital,Capital Medical University from February 2020 to September 2020 were selected,whose average age was(4.43±1.61 years).The scan protocol of ultralow dose CT was(0.05 mGy).The reconstructed images included 6 groups,which were respectively filtered reflection projection(FBP)image with 0.625 mm thickness,50%adaptive iterative recombination(ASIR-V)images,100%ASIR-V images,low energy DL(DL-L),medium energy DL(DL-M),and high energy DL(DL-H).The automatically segmentation software was used to conduct automatically segmentation for airway,and the success rate of automatic segmentation was recorded.For images that were successful segmented,a 5-point scale was adopted to subjectively evaluate the displayed quality for airway(5 point is the best).In addition,the CT values and noise values of the images of 6 groups for airway were objectively measured.Results:The success rate of automatic segmentation of DL-H image was the highest(60.98%),and that of the 100%ASIR-V was the lowest(39.02%).The subjective score of DL-H image of the automatic segmentation was the highest(4.06±0.55)point,and that of 100%ASIR-V was the lowest(2.44±0.76)point.DL-H can display more fine and small airways.The noise values of objective measurement showed that both of DL-H and 100%ASIR-V had the lowest noise value,and there was no statistical difference in that between them.Conclusion:The use of high energy deep learning iterative reconstruction(DLIR)algorithm can improve the success rate and display effect of automatic segmentation of ultralow dose CT for chest of children on airway,and DLIR is contribute to improve the accuracy of automatic segmentation algorithm of artificial intelligence.

CT is a commonly examination method in pediatric clinical practice.Formulating and popularizing low-dose pediatric CT scanning protocols and constructing a standard image quality evaluation system are the key directions of low-dose pediatric CT imaging.In recent years,domestic CT equipment achieved technological breakthroughs in hardware performance and image reconstruction algorithms,which could provide new paths for pediatric low-dose CT imaging in children combining with artificial intelligence technology.The current status of scanning protocols,the establishment of imaging quality evaluation system and the clinical promotion,as well as challenges of domestic CT in pediatric low-dose CT imaging were reviewed in this article.

Purpose To evaluate the image quality improvement of deep learning iterative reconstruction(DLIR)on pediatric head CT images of head injury and to evaluate the performance of DLIR and conventional adaptive statistical iterative reconstruction-veo(ASIR-V)of noise and image texture of CT image in children's head trauma.Materials and Methods A total of 80 cases in Beijing Children's Hospital,Capital Medical University from December 7th to 11th 2020 of children's head low-dose CT were retrospectively selected.Scan voltage was 120 kV.Scan current was 150-220 mA.The raw data were reconstructed into 5 mm thick slice and 0.625 mm thin slice brain window and bone window images.50%ASIR-V and high weight DLIR images(DL-H)were reconstructed,respectively.A 4-point system was used to subjectively evaluate the display of sulcus,brain matter and bone.The number of lesions in each group was counted.The CT value and image noise values of gray matter and white matter were measured,and the contrast to noise ratio was calculated,then measured the blur metric index was measured in the same slice.The differences between the two image reconstruction methods were compared.Results Compared to 50%ASIR-V images,DL-H significantly improved the display ability of the sulcus and ventricles,as well as the display ability of the brain parenchyma(W=5.5-22.2,all P<0.05)in both slice thickness.There was no statistically significant difference in the display ability of the sulcus and ventricles between 5 mm 50%ASIR-V and 0.625 mm DL-H images(W=0.9,2.0,P=0.32,0.05,respectively).In terms of bone display ability,all images could achieve a maximum score of 4.0.A total of 35 lesions were found in 80 patients via 5 mm 50%ASIR-V and DL-H images,including 12 hemorrhagic lesions,1 intracranial gas,9 fractures,and 13 soft tissue swelling.In terms of objective evaluation,the noise level of DL-H images was significantly lower than that of 50%ASIR-V images(t=21.4-35.7,all P<0.05),and there was no statistically significant difference in noise and contrast noise ratio between 5 mm 50%ASIR-V and 0.625 mm DL-H images(t=1.7-2.2,all P≥0.05).The blur metric index showed that DL-H was superior to 50%ASIR-V images(t=6.1,10.0,both P<0.05),and there was no statistically significant difference in blur metric index between 0.625 mm DL-H and 5 mm 50%ASIR-V images(t=2.6,P=0.28).Conclusion DLIR can improve the CT image quality and image texture of children's head trauma,0.625 mm DL-H image quality is close to 5 mm 50%ASIR-V image,which can meet the diagnostic requirements,and possible to further reduce the radiation dose.

Objective:To investigate the clinical efficacy of TiRobot-assisted minimally invasive percutaneous screw fixation for pelvic fractures.Methods:The clinical data of 44 patients with pelvic fracture were retrospectively analyzed who had undergone TiRobot-assisted minimally invasive percutaneous screw fixation from May 2018 to April 2021 at Department of Orthopedic Traumatology, The First Hospital of Jilin University. There were 30 males and 14 females, aged from 11 to 78 years (average, 40.6 years). According to the Tile classification, there were 20 type C1 fractures, 23 type C2 fractures and one type C3 fracture. The time from injury to operation averaged 8.2 days (from 1 to 41 days). The minimally invasive percutaneous screw fixation was assisted by the orthopaedic TiRobot in all patients. Operation time, fluoroscopy time, reduction quality, complications and functional recovery at the final follow-up were recorded and analyzed.Results:A total of 96 screws were implanted in this cohort. The total fluoroscopy time ranged from 17 to 66 s, with an average of 17.8 s for each single screw. The operation time ranged from 50 to 355 min, averaging 179.7 min. According to the Matta criteria, the reduction quality was rated as excellent in 36 cases, as good in 5 and as fair in 3, yielding an excellent and good rate of 93.2%(41/44). All the 44 patients were followed up for 6 to 42 months (average, 20.4 months). The fracture healing time ranged from 2 to 6 months, averaging 3.3 months. The Majeed scores at the final follow-up ranged from 51 to 100 points (average, 83.7 points); there were 28 excellent, 8 good, 7 fair and one poor cases, giving an excellent to good rate of 81.8% (36/44). Follow-up found no such complications as iatrogenic neurovascular injury, incision infection, malunion, implant loosening or fracture re-displacement in all the 44 patients.Conclusion:TiRobot-assisted minimally invasive internal fixation can result in fine clinical efficacy for pelvic fractures, showing advantages of accuracy, minimal invasion and safety.

Objective:To understand the current situation of CT radiation dose in children all over our country, and to explore the diagnostic reference level (DRL) of CT in children.Methods:The radiation dose reports of pediatric CT examination were collected end to November 30, 2021 and divided into five age groups: 0-1 month,>1 month-4 years,>4-10 years,>10-14 years and >14-18 years. There were 9 scanning item such as head, nasal sinus, temporal bone, neck, chest, abdomen, head enhanced CT, chest enhanced CT and abdomen enhanced CT. In each item, volume CT dose index (CTDI vol) and dose length product (DLP) were selected as radiation dose parameters, the 75% percentile were selected for DRL. The DRL results of head, chest and abdomen were compared with the DRL published by Chinese Society of Radiology and European Commission. Results:From March 2019 to November 2021, a total of 33 hospitals in 23 provinces were collected, including 20 children′s specialized hospitals, 11 women′s and children′s hospitals and 2 general hospitals, including 19 135 children′s CT scans. The DRL of 45 subgroups according to 5 age groups and 9 scanning items were obtained. The DRL results showed that the CTDI vol in five age groups was 26.9-42.8 mGy, and the DLP was 347-694 mGy·cm for head; 3.5-8.0 mGy, 54-293 mGy·cm for chest; and 6.3-13.2 mGy, 155-564 mGy·cm for abdomen. The DRL of the age group >4-10 years group in this investigation was agreed to the DRL of Chinese Society of Radiology. Compared with the European guidelines, there was little difference in the radiation dose of head scan, while the radiation dose of chest and abdomen in the young age group increased significantly. Conclusion:This survey reveals the radiation dose level distribution of children CT in our country. The radiation dose level of some items was inconsistent with the DRL of relevant international organizations. So our own DRL is needed to be set up according to the actual clinical reality of our country as a guideline.

Objective:Gasless laparoscopic surgery using lifting device was first introduced in 1993 mainly for general surgery and gynecology. Here we report its application in bifid rib treatment and explore the feasibility and safety of the surgery.Methods:From July 2008 to December 2019, according to the enrollment criteria, 278 patients of bifid ribs were treated at the Department of Thoracic Surgery, Beijing Children’s Hospital, Capital Medical University, including 183 males and 95 females, the mean age was(5.7±2.5) years old. There were 242 cases of single bifid rib and 36 cases of multiple bifid ribs. The bifid ribs were more common on the right side, as 184 cases had bifid ribs on right side, while only 68 cases on the left side and 26 cases on both sides. Patients’ clinical data were retrospectively summarized and analyzed, including the patients’ gender, age, location and type of bifid rib, perioperative outcome, and follow-up.Results:All the 278 patients successfully completed the operation. The abnormality was most frequently found in the fifth rib(incidence ranking: fifth > fourth > third > sixth). The mean operation time was(64.5±16.1)min, and the mean blood loss was(4.8±2.1)ml. No serious complications occurred during the surgery. Follow-up was done for 7 to 120 months, and no recurrent patients were observed.Conclusion:Gasless endoscopy with lifting device has been used as a safe and effective method to treat bifid ribs in our hospital. This surgery leads to less injury, smaller incision, and no scars on the front chest. Gasless endoscopic surgery with lifting device can be one of the options for correcting bifid ribs.

OBJECTIVES: To explore the risk factors for femoral neck fracture in elderly population. METHODS: A total of 124 elderly patients (≥60 years old) in hospital for trauma were enrolled, including 71 patients (57%) with femoral neck fracture and 53 non-femoral neck fracture patients (43%). All patients' age, gender, body mass index (BMI), bone mineral density (BMD), thigh length and average circumference were collected. Single factor analysis and multivariate logistic regression analysis were performed to explore whether the above factors were risk factors for femoral neck fracture. RESULTS: Single factor analysis showed that the age, gender, BMI, BMD, thigh length, and average thigh circumference between the 2 groups were statistically different (all CONCLUSIONS Older age, female, lower BMI index (low body weight), lower BMD (osteoporosis), longer thigh length, and lower average circumference are risk factors for femoral neck fracture in the elderly population.
Absorptiometry, Photon ; Aged ; Body Mass Index ; Bone Density ; Female ; Femoral Neck Fractures/etiology* ; Humans ; Middle Aged ; Osteoporosis ; Risk Factors

Objective:To demonstrate whether image quality and measurement accuracy of vessel wall thickening could be improved using a deep learning image reconstruction (DLIR) algorithm in children with Takayasu arteritis.Methods:From September 2019 to April 2020, 32 patients with Takayasu arteritis underwent low-dose contrast-enhanced CT with 100 kVp in Beijing Children′s Hospital were enrolled retrospectively. The raw data were reconstructed at 0.625 mm slice thickness using the filtered back projection (FBP), 50% adaptive statistical iterative reconstruction-V (ASIR-V) at 50% (50%ASIR-V), ASIR-V at 100% (100%ASIR-V) and DLIR. Subjective evaluation including the image quality of vessel wall identification, overall image noise and diagnostic confidence were evaluated using a 5 points scales by 2 observers. Objective evaluation including the thickness and standard deviation of vessel wall were measured, then the coefficient of variation (CV) was calculated. The CT value and noise of aorta were measured to calculate the contrast to noise ratio (CNR) of image. Friedman test was used to compare the differences of subjective scores among the four groups, and the analysis of variance of random blocks was used to compare the differences of objective measurement indices.Results:In terms of subjective score results, there was no significant difference between 100%ASIR-V and DLIR of overall image noise ( P>0.05), and the image scores of the two groups were higher than those of FBP and 50%ASIR-V (all P<0.05). The vessel wall identification and diagnostic confidence of DLIR were higher than those of other images (all P<0.05). The objective measurement results showed that the standard deviation and CV of vessel wall thickness in DLIR were significantly lower than those in other images (all P<0.05). There was no significant difference in vascular noise, muscle noise and CNR between 100%ASIR-V and DLIR (all P>0.05), which were lower than those in FBP and 50%ASIR-V (all P<0.05). Compared with 50%ASIR-V, the CV of DLIR was reduced by 22.9%, and the CNR was increased by 46.8%. Conclusion:DLIR can improve the overall image quality of CECT in children with Takayasu arteritis and the measurement accuracy of vascular wall, making it possible to further reduce the radiation dose.