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Objective The study aims to investigate the effects of different adaptive statistical iterative reconstruction-V（ ASiR-V） and convolution kernel parameters on stability of CT auto-segmentation which is based on deep learning. Method Twenty patients who have received pelvic radiotherapy were selected and different reconstruction parameters were used to establish CT images dataset. Then structures including three soft tissue organs (bladder, bowelbag, small intestine) and five bone organs (left and right femoral head, left and right femur, pelvic) were segmented automatically by deep learning neural network. Performance was evaluated by dice similarity coefficient（ DSC） and Hausdorff distance, using filter back projection(FBP) as the reference. Results Auto-segmentation of deep learning is greatly affected by ASIR-V, but less affected by convolution kernel, especially in soft tissues. Conclusion The stability of auto-segmentation is affected by parameter selection of reconstruction algorithm. In practical application, it is necessary to find a balance between image quality and segmentation quality, or improve segmentation network to enhance the stability of auto-segmentation.
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Humans , Algorithms , Image Processing, Computer-Assisted , Neural Networks, Computer , Radiation Dosage , Tomography, X-Ray ComputedABSTRACT
Clinical applications of cone-beam breast CT(CBBCT) are hindered by relatively higher radiation dose and longer scan time. This study proposes sparse-view CBBCT, i.e. with a small number of projections, to overcome the above bottlenecks. A deep learning method - conditional generative adversarial network constrained by image edges (ECGAN) - is proposed to suppress artifacts on sparse-view CBBCT images reconstructed by filtered backprojection (FBP). The discriminator of the ECGAN is the combination of patchGAN and LSGAN for preserving high frequency information, with a modified U-net as the generator. To further preserve subtle structures and micro calcifications which are particularly important for breast cancer screening and diagnosis, edge images of CBBCT are added to both the generator and the discriminator to guide the learning. The proposed algorithm has been evaluated on 20 clinical raw datasets of CBBCT. ECGAN substantially improves the image qualities of sparse-view CBBCT, with a performance superior to those of total variation (TV) based iterative reconstruction and FBPConvNet based post-processing. On one CBBCT case with the projection number reduced from 300 to 100, ECGAN enhances peak-signal-to-noise ratio (PSNR) and structural similarity (SSIM) on FBP reconstruction from 24.26 and 0.812 to 37.78 and 0.963, respectively. These results indicate that ECGAN successfully reduces radiation dose and scan time of CBBCT by 1/3 with only small image degradations.
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Humans , Algorithms , Breast , Cone-Beam Computed Tomography , Image Processing, Computer-Assisted , Phantoms, Imaging , Tomography, X-Ray ComputedABSTRACT
Objective: To evaluate the application of 3D-CT airway reconstruction images to predicting difficult airway in patients with odontogenic infections. Methods: A retrospective analysis was performed on patients with odontogenic infections who were treated by incision and drainage under general anesthesia at Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from August 2017 to July 2019, and patients who were evaluated as difficult airway receiving awake tracheal intubation were selected as the case group (n=27). From the "Hospital Inpatient System", patients who were evaluated as non-difficult airway receiving fast induction were selected as the control group (n=27). Maxillofacial CT scans of all the patients were collected. The Dolphin Imaging software version 11.9 Premium was used to perform 3D-CT reconstruction of the airway. The upper airway was divided into oropharynx and hypopharynx, and the oropharynx was divided into velopharynx and glossopharyngeal. The indicators such as airway volume, median sagittal area, minimal cross-sectional area, and thickness of pharyngeal soft tissue were collected. The indicators of the difference between the two groups were compared and selected. Logistic re-gression analysis was conducted to investigate the association of these factors with difficult airway. Results: The volume of velopharynx and hypopharynx, the median sagittal area of velopharynx, oropharynx and hypopharynx, the mean cross-sectional area of velopharynx and hypopharynx, the minimal cross-sectional area and its lateral dimension of oropharyngeal of patients in the case group were significantly smaller than those of the controls (P<0.05). Thickness of pharyngeal soft tissue in the most inferior-anterior point of the second and the third cervical vertebrae of patients in the case group was significantly higher than that of the controls (P<0.05). The Logistic regression analysis showed that the median sagittal area of velopharynx, oropharynx and hypopharynx, the volume and mean cross-sectional area of hy-popharynx, and thickness of pharyngeal soft tissue in the most inferior-anterior point of the second and the third cervical vertebrae of patients were related to difficult airway in patients with odontogenic infections (P<0.05). Conclusion: Airway 3D-CT reconstruction can clearly show the airway anatomy of patients with odontogenic infections. The median sagittal area of pharynx, the volume and mean cross-sectional area of hypopharynx, and thickness of pharyngeal soft tissue in the most inferior-anterior point of the second and the third cervical vertebrae may will be used as predictors of difficult airway in patients with odontogenic infections.
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BACKGROUND: Percutaneous kyphoplasty (PKP) is an effective method for treating osteoporotic vertebral compression fracture. Although satisfactory clinical outcomes can be achieved, bone cement leakage is still one of the main complications of PKP. Based on previous studies, there are many high risk factors for bone cement leakage into the spinal canal; however, less attention to the posterior wall morphology of different vertebral bodies may be an important reason for bone cement leakage into spinal canal. OBJECTIVE: To investigate the effect of thoracic and lumbar vertebral posterior wall morphology in the patients with osteoporotic vertebral compression fracture on bone cement leakage into the spinal canal during the PKP. METHODS: The clinical data of osteoporotic vertebral compression fracture patients with PKP were selected. There were 98 osteoporotic vertebral compression fracture patients with CT scan and three-dimensional reconstruction image data from T6 to L5. The three-dimensional reconstruction of CT and multiplanar reconstruction were used to measure the depth of the concave vertebral posterior wall (OC) and the corresponding middle-sagittal diameter of the vertebra (PC) of the non-fractured vertebral body, the ratio of OC to PC was calculated. All subjects were divided into thoracic group (T6-T12) and lumbar group (L1-L5) based on the location of measured vertebral, and the differences of the OC between groups were compared. 357 patients (548 vertebrae) with osteoporotic vertebral compression fracture without CT three-dimensional reconstruction underwent PKP within the same period. They were also divided into thoracic vertebra and lumbar vertebra groups. The degree of bone cement leakage into the spinal canal was compared between thoracic and lumbar vertebra groups. RESULTS AND CONCLUSION: (1)The morphological parameters of posterior vertebral wall in 98 patients showed that the depth of the concave vertebral posterior wall gradually (OC) deepened from T6toT12, with an average of 4.6 mm. The depth became gradually shallow from L1 to L5, with an average of 0.6 mm. The ratio of the depth of the concave vertebral posterior wall to the corresponding middle-sagittal diameter of the vertebra was approximately 16% (1/6) from T6toT12. The average value of ratios from Li to U was 3%. The ratios in lumbar vertebra were significantly decreased compared with thoracic vertebra (16%, 1/6). (2) Results form 357 patients who underwent PKP at the same time showed that the rate of bone cement leakage into spinal canal was 10.2% (31/304) in the thoracic vertebra group during the PKP, and the rate of lumbar vertebra group was 3.7% (9/244). In the thoracic group, the average maximal sagittal diameter of the bone cement intruded spinal canal was (3.1 ±0.2) mm, the average maximal area of the bone cement intruded spinal canal was (30.8±0.3) mm2, and the spinal canal encroachment rate was (22.5±0.2)%. In the lumbar group, the average maximal sagittal diameter of the bone cement intruded spinal canal was (1.4±0.1) mm, the average maximal area of the bone cement intruded spinal canal was (14.9±0.2) mm2, and the spinal canal encroachment rate was (11,4±0.3)%. There was significant difference between thoracic and lumbar groups (P<0.05). (3) The above results imply that due to the presence of OC structure in the middle and lower thoracic vertebra, it is possible to reduce the occurrence of bone cement leakage into spinal canal through avoiding bone cement distribution over the posterior 1/6 (16%) of vertebral body in PKP. The effect of the difference between thoracic and lumbar vertebral posterior wall morphology in osteoporotic vertebral compression fracture patients on bone cement leakage into the spinal canal during the PKP may be one of the reasons why the rate of bone cement leakage into spinal canal in thoracic vertebra significantly higher than that in lumbar vertebra. The study protocol was approved by the Ethics Committee of the Affiliated Hospital of Southwest Medical University (approval No. K2018008).
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Objective To investigate the anatomical structure of arterial vessels in the head and neck of miniature pigs and the related application of vascular cast specimens,and the technology of three-dimensional model reconstruction by CT imaging. Methods A vascular cast specimen of a miniature pig head and neck was made by a 128-slice spiral CT scanning,and a three-dimensional model of the arterial vessels in the head and neck of the miniature pig was reconstructed. Results The cast specimen clearly showed the distribution and running characteristics of the arteries in the head and neck of a miniature pig. The three-dimensional digital model was realistic and stereoscopic,showing the running and distribution of arteries from multiple angles and layers. Conclusions The distribution and running characteristics of arterial vessels in the head and neck of a miniature pig have been investigated by the combination of cast specimen and three-dimensional digital model,providing a morphological reference for the establishment of pig cerebrovascular models in respects of both solid specimen and virtualized model.
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Objective To investigate the effect of head extension angle to glottis exposure by using three-dimensional CT reconstruction sagittal plane images of upper airway.Methods There were 80 patients,aged 7-78 years old,who had been scanned by helical CT in the head and neck.Reconstructed images were obtained by AW4.4 workstation and the following parameter was measured:angle α(A0 group),the angle created by the upper central incisor and root of epiglottis(angular vertex) and midpoint of glottis.Reconstructed images were printed according to the actual size of human body in a ratio of 1∶ 1,then the images were cut off from the upper central incisor to root of epiglottis by a section of arcs.Increasing the degree of angle α by clockwise to hypothetically increase the angle of head extension.The glottis was exposed by using a paper-made laryngoscope(Macintosh) model,and the success rate of glottis exposure was recorded when the degree of angle α was respectively increased 10°(A10 group),20°(A20 group),and 30°(A30 group).Results Compared with A0 group,the success rate of glottis exposure increased significantly in A10 group,A20 group and A30 group.The success rate of glottis exposure in A20 group and A30 group was significantly higher than A10 group.Compared with A20 group,the success rate of glottis exposure obviously increased in A30 group.Conclusion Based on CT reconstruction images of upper airway,we can analog study the effect of head extension angle to glottis exposure.
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Objective To explore the clinical effect of transplantation of autologous fat with stromal vascular fraction for breast augmentation.Methods From September 2012 to March 2014,15 people accepted breast augmentation by transplanting autologous fat with SVF under local anaesthesia.Three-dimensional computer tomography reconstruction (3D-CT reconstruction) was applied preoperatively and postoperatively,the data of the thickness of breast's subcutaneous tissue was compared to observe the breast contour improvement.Results Autologous fat was injected 2 times in 3 cases,and the rest were 1 time.6 months after operation,13 cases were satisfied with the results,and 2 cases were quite satisfied.3D-CT reconstruction was performed before operation and 6 months after operation;statistics showed that before operation the thickness of breast subcutaneous tissue of the right side was (11±4) mm,the left side was (11±6) mm;6 months after operation the right side was (14±3) mm,the left side was (16±3) mm (P＞0.05).The breast was soft,no major complication such as nodules,cysts or calcification were seen.Conclusions The transplantation of SVF with autologous fat is a safe,effective procedure for breast augmentation.3D-CT reconstruction can show more details of breast structures,which is a more effective method to guide and evaluate the lipotrans plantation.
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Objective To observe the surgical results of milling technique in treating mandibular angle hypertrophy through an intraoral approach and the effect of three-dimensional computer tomography (3D-CT) reconstruction.Methods Milling-technique was used to treat mandibular angle hypertrophy of 43 patients through intraoral approach under local anaesthesia.3D-CT was applied preoperatively and postoperatively,the data of mandibular angle and masseter muscle thickness were compared preoperatively and postoperatively.The facial contour improvement was also observed.Results Of 43 cases,33 cases were followed-up for 4 to 24 months after operation.The majority of patients were satisfied with the aesthetic results,changes of anterior and lateral view of basifacial part were obvious,the curve of the mandibular angle was smooth and the shape was natural; no major complications such as facial nerve injury or malfracture were seen.Conclusions Milling-technique is a safe,effective and simple method for mandibular angle reduction,and 3D-CT reconstruction has a positive effect preoperatively and postoperatively.
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Objective To improve the accuracy of diagnosis and differential diagnosis of nonossifying fibroma (NOF) by comparing with the image features of X-ray and CT and pathological characteristics,Methods The images of X-ray and CT of 28 patients underwent surgery and pathological confirmed NOF were studied retrospectively.Results NOF often occurred in the metaphysis of long bone or backbone with mild clinical symptoms.Eighteen lesions occurred in tibia,9 in femur and 1 in humerus.In 19 cortical cases,there was a single room or multiple rooms translucent zone in cortex or subcortex with dense surrounding.In 9 medullary cases,lesions as a single room or multiple rooms ranslucent zone with dense surrounding developed in the central area of the bone with thinning corex slightly bulg ed to periphery.Conclusion The images of NOF have some characteristic.X-ray and CT are very useful tools in diagnosis of NOF.Thin layer scanning and multiplanar reconstruction of multi-layers spiral CT can more clearly show the imaging features of NOF.
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Objective:To evaluate the contour and functional restoration in segmental defects of mandibles with three-dimensional CT(3D-CT) reconstrction.Methods: Twenty-four patients(16 males,8 females) underwent mandibular reconstruction by using nonvascularized bone grafts.In 24 patients,nonvascularized grafts from the iliac crests(n=11),the ribs(n=10),and the autogenous mandibular bones(AMB)(n=3)were used.`The length of segmental bone grafts ranged from 6 to 20 cm,with an average of 9.8 cm,for the defects with 5 to 20 cm.Both contour and functional effects with reconstructed mandible were determined and analysed via 3D-CT.Results: All free bone grafts were successfully healed.Among them,17 patients showed better soft tissue contour.Only 14 patients were satisfied for skeletal contour.All patients could wear a conventional denture after reconstruction.Conclusion:Facial contour can be achieved via mandibular reconstruction with iliac,rib and AMB.3D-CT can provide anatomy position for the surgical planning.It is an important mean to compensate inadequate of general X-ray and convention CT.Meanwhile it can be used for estimating the reconstruction effects while follow-up.
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Technical advances in computer image analysis have made possible three-dimensional(3D) surface Informations of anatomic structures from contiguous axial CT slices. We have recently utilized this 3D CT reconstruction with spiral CT scanner in 6 consecutive patients with primary or secondary craniosynostosis to assess the presence and extent of synostosis, associated calvarial deformity and to facilitate surgical planning of the craniectomy site. High resolution 3-mm contiguous CT sections were obtained and 3D shaded-surface reconstruction image generated after reformation at 2-mm interval. In each case 3D CT demonstrated the exact extent of synostosis, and in 3 cases it was confirmed by surgical inspection. 3D CT images facilitated surgical planning by precisely localizing the proper site for craniectomy. Three-dimensional CT with shaded-surface display may be a useful adjunct to imaging and surgical planning in the patients with craniosynostosis, as well as a useful follow-up imaging study during observation or after surgery.
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Humans , Congenital Abnormalities , Craniosynostoses , Follow-Up Studies , Synostosis , Tomography, Spiral ComputedABSTRACT
The ultimate goal of radiotherapy is to result in complete local control of tumor while sparing the surrounding normal tissues as much as possible. Since the development of CT in 1970s, patient's anatomical normal tissues and the site and extent of infiltration of tumor were identified almost accurately. In addition, the isodose distribution of delivered radiation to target tumor was shown in each cross-section. In the treatment planning of head and neck cancers, CT-reconstruction provided almost 3-dimensinonal inter-relationship between tumor and normal tissues. The utilization of imaging system of the CT scanner made it possible to illustrate in superposition the patient structure image, the radiation beams, and the isodose distributions. Thus it was possible to deliver radiation enough to control the local disease, and to avoid unnecessary administration of radiation to normal tissue such as spinal cord. CT-reconstructed image in axial, sagittal, and coronal planes suggested 3-dimensional radiotherapy treatment planning be possible and practical instead of conventional 2-dimensional planning at coronal plane.