Considering the survival rate of small animals and the continuity of the experiments, high-dose X-ray shooting process is not suitable for the small animals in computed tomography (CT) experiments. But the low-dose process results with images might be polluted by noises which are not conducive for the experiments. In order to solve this problem, we in this paper introduce a global dictionary learning based denoising method to apply the promotion of the low dose CT image. We at first adopted the K-means singular value decomposition (K-SVD) algorithm to train a global dictionary based on the high dose CT image. Then, the noise image could be decomposed into sparse component which was free from noise through the orthogonal matching pursuit (OMP) algorithm. Finally, the noise-free image could be achieved by reconstructing the image only with its sparse components. The experiments results showed that the method we proposed here could decrease the noise efficiently and remain the details, and it would help promote the low dose image quality and increase the survival rate of the small animals.
Objective To discuss the application of dual-source computed tomography （CT） low dose technology in the upper abdomen enhanced inspection. Methods?Six hundred consecutive patients from July 2011 to February 2012 in this hospital were orderly divided into ordinal tube current （210?mAs） group and low dose tube current group （200 mAs，190?mAs，180?mAs，170?mAs，and 165?mAs）. The standard deviation （SD） of subcutaneous fat，signal to noise ratio （SNR） of liver and pancreas， contrast to noise ratio （CNR） of liver-erector spinae and pancreas-erector spinae，score of subjective diagnosis and the indexes of radiation dose，including CT dose index （CTDI），dose length product （DLP），effective dose （ED） were measured，calculated，and assessed respectively on CT images of arterial phase and portal phase from each group. Results?The SD of subcutaneous fat， SNRs of liver and pancreas，score of subjective diagnosis，and the CTDI，DLP，ED of CT images in arterial phase and portal phase were significantly different from each other （P＜0.05），while CNRs of liver-erector spinae and pancreas-erector spinae were not statistically significant （P＞0.05）. The SNR，radiation dose，and score of subjective diagnosis of the 165 mAs tube current group were the lowest among all the groups，but the images of the 165 mAs tube current group could not fulfill the need of diagnosis. Conclusions?It is really feasible that the method of decreasing tube current gradually in the upper abdomen enhanced CT inspection could ensure that the radiologists could adapt the low dose image bit by bit，and this methods could be popularized to all kinds of CT facilities we own currently. The images with 170?mAs as tube current in the upper abdomen enhanced inspection of dual-source CT could fulfill the need of diagnosis，and the radiation dose of patients is apparently lower than that the conventional scan．
Objective To evaluate the security and clinical value of the combination of three-dimensional computed tomography-bronchography and angiography (3D-CTBA) and indocyanine green (ICG) staining in video-assisted thoracic surgery (VATS) segmentectomy. Methods The clinical data of 125 patients who received VATS segmentectomy from January 2020 to January 2021 in our hospital were retrospectively analyzed. There were 40 (32.0%) males and 85 (68.0%) females with an average age of 54.8±11.1 years. Results The procedure was almost identical to the preoperative simulation. All intersegment planes were displayed successfully by ICG reverse staining method. There was no allergic patient. A total of 130 pathological specimens were obtained from the 125 patients. The mean operation time was 126.8±41.9 min, the time of first appearance of fluorescence was 22.7±4.9 s, the mean mark time was 65.6±20.3 s, the median blood loss was 20.0 (10.0-400.0) mL, the postoperative hospital stay was 5.6 (4.0-28.0) d, and the postoperative retention of chest tube time was 3.2 (2.0-25.0) d. Pathological results showed that microinvasive adenocarcinoma was the most common type (38.5%, 50/130), followed by invasive adenocarcinoma (36.9%, 48/130); there were 3 metastatic tumors (3/130, 2.3%).Conclusion The combination of 3D-CTBA and ICG reverse staining is proved to be a safe, necessary and feasible method. It solves the difficult work encountered in the procedure of segmentectomy, and it is worth popularizing and applying in clinic.
Lung four dimensional computed tomography (4D-CT) can lead to accurate radiotherapy. However, for the safety of patients, the scan spacing of 4D-CT cannot be too small so that the inter-slice resolution of lung 4D-CT is low, and thus the coronal and sagittal images need to be interpolated to obtain high-resolution images. This paper presents a super-resolution reconstruction technique based on multi-model Gaussian process regression. We use the high-resolution transversal images and the corresponding low-resolution images as the training sets. The high-resolution pixels of the coronal and sagittal images can be predicted by constructing multiple Gaussian process regression models. The experimental results show that our method is superior to bicubic algorithm, projections onto convex sets, sparse coding, multi-phase similarity based method and Gaussian process regression method based on self-learning block in terms of the edge and detail recovery. The results demonstrate that the proposed method can effectively improve the quality of lung 4D-CT images, and potentially be applied to better image-guided radiation therapy of lung cancer.
For tooth segmentation problem on the three-dimensional computed tomography (CT) volume data, this paper proposes a regional adaptive deformable model for tooth structure measurement of CT images. The proposed method combines the automatic thresholding segmentation, CV active contour model, and graph-cut. Firstly, we achieved the segmentation and location of dental crowns by automatic thresholding segmentation. And then by using the above segmentation result as the initial contour, we utilized active contour method to slice gradually the segment of remaining tooth. By incorporating active contour and graph-cut then, we realized the accurate segmentation for tooth root, which is the most difficult to be segmented. The experimental results showed that the proposed tooth structure measurement accurately and automatically segmented dental crowns from CT data, and then rapidly and accurately segmented the tooth neck and tooth root. The structure of tooth could be effectively segmented from CT data by using the proposed method. Experimental results indicated that the proposed method was rather robust and accurate, and could effectively assist the doctor for diagnosis in clinical treatment.
Objective To explore the early diagnostic value of single photon emission computed tomography(SPECT), thoracic computed tomography(CT),and chest X-ray for closed chest trauma. Methods To establish the animal model of unilateral chest impact trauma,to adopt SPECT, thoracic CT, and chest X-ray for early diagnosis of closed chest trauma,and to compare these findings with postmortem examination. Results Thirty minutes after blunt chest trauma, the region of interesting (ROI) between traumatized lung and the heart (ROI2/ROI1) immediately increased to the peak six hours after trauma; on the contralateral lung, the ratio (ROI3/ROI1) increased slowly and reached the peak after six hours, these ratio was still smaller than that of the traumatized lung. These differences were significant (Plt;0.01). Conclusions Chest X-ray is still the most fundamental diagnostic method of chest trauma,but it was thought that the patients of severe chest trauma and multiple injuries should be examined early by thoracic CT. Radionuclide imaging have more diagnostic value than chest X-ray on pulmonary contusion. The diagnostic sensibility to pulmonary contusion of thoracic CT is superior to conventional radiograph,but thoracic CT is inferior to SPECT on exploring exudation and edema of pulmonary contusion. Thoracic CT is superior to conventional radiograph on diagnosis of chest trauma,therefore patients of severe chest trauma and multiple injuries should be adopted to thoracic CT examination at emergency room in order to be diagnosed as soon as possible.
ObjectiveTo evaluate the clinical feasibility and safety of CT-guided percutaneous microwave ablation for peripheral solitary pulmonary nodules.MethodsThe imaging and clinical data of 33 patients with pulmonary nodule less than 3 cm in diameter treated by CT-guided microwave ablation treatment (PMAT) in our hospital from July 2018 to December 2019 were retrospectively analyzed. There were 21 males and 12 females aged 38-90 (67.6±13.4) years. Among them, 26 patients were confirmed with lung cancer by biopsy and 7 patients were clinically considered as partial malignant lesions. The average diameter of 33 nodules was 0.6-3.0 (1.8±0.6) cm. The 3- and 6-month follow-up CT was performed to evaluate the therapy method by comparing the diameter and enhancement degree of lesions with 1-month CT manifestation. Short-term treatment analysis including complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) was calculated according to the WHO modified response evaluation criteria in solid tumor (mRECIST) for short-term efficacy evaluation. Eventually the result of response rate (RR) was calculated. Progression-free survival was obtained by Kaplan–Meier analysis.ResultsCT-guided percutaneous microwave ablation was successfully conducted in all patients. Three patients suffered slight pneumothorax. There were 18 (54.5%) patients who achieved CR, 9 (27.3%) patients PR, 4 (12.1%) patients SD and 2 (6.1%) patients PD. The short-term follow-up effective rate was 81.8%. Logistic analysis demonstrated that primary and metastatic pulmonary nodules had no difference in progression-free time (log-rank P=0.624).ConclusionPMAT is of high success rate for the treatment of solitary pulmonary nodules without severe complications, which can be used as an effective alternative treatment for nonsurgical candidates.
To investigate the impact of respiratory movement to determine the target volume on cone beam CT (CBCT) for lung tumor,we used CIRS dynamic thorax phantom (Model-CIRS008) to simulate the sinusoidal motion of lung tumor. With a constant amplitude, the ratio of the time of near-end-expiratory and near-end- inspiratory (E/I) changed when it was scanned with CBCT. We analyzed the contrast changes of target by extracting the CT value of each pixel on the center line of the target movement direction. The targets were contoured with region growing method and compared with the motion volume generated by the tumor trajectory method. The result showed that the contrast of near-end-expiratory increased and the contrast of near-end-inspiratory decreased with increasing E/I. The contoured volume generated by region growing method decreased with increasing E/I. When E/I=4, the amplitude A=1 cm, diameter of 1 cm and 3 cm target volumes were reduced by 48.2% and 22.7%.The study showed that CBCT was not suitable to be used to accurately determine the range of lung tumor movement. The internal target volume (ITV) may be underestimated in CBCT images.
ObjectiveTo investigate the CT signs and clinicopathological features of peripheral cavitary lung adenocarcinoma with the largest diameter less than or equal to 3 cm.Methods From January 2015 to December 2017, the CT signs and clinicopathological fertures of 51 patients with ≤3 cm peripheral cavitary lung adenocarcinoma diagnosed by chest CT and surgical pathology were retrospectively analyzed. Furthermore, CT signs and clinicopathological features of thick-walled cavitary lung adenocarcinoma and thin-walled cavitary lung adenocarcinoma were compared. There were 29 males and 22 females at age of 62 (56, 67) years.ResultsThere were 27 thick-walled cavitary lung adenocarcinoma and 24 thin-walled cavitary lung adenocarcinoma. Thick-walled cavitary adenocarcinoma had greater SUVmax [6.5 (3.7, 9.7) vs. 2.2 (1.4, 3.8), P=0.019], larger cavity wall thickness (11.8±4.6 mm vs. 7.6±3.7 mm, P=0.001), larger tumor tissue size [2.1 (1.7, 2.8) cm vs. 1.6 (1.2, 2.0) cm, P=0.006], and more solid nodules (17 patients vs. 8 patients, P=0.035). Thin-walled cavitary adenocarcinoma had more smoking history (12 patients vs. 6 patients, P=0.038), larger cavity size [12.3 (9.2, 16.6) mm vs. 4.4 (2.8, 7.1) mm, P=0.000], and larger proportion of cavities [0.30 (0.19, 0.37) vs. 0.03 (0.01, 0.09), P=0.000]. On CT signs, there were more features of irregular inner wall (19 patients vs. 6 patients, P=0.000), intra-cystic separation (16 patients vs. 6 patients, P=0.001) and vessels through the cystic cavity (10 patients vs. 1 patient, P=0.001) in thin-walled caviraty lung adenocarcinoma.ConclusionPeripheral cavitary lung adenocarcinoma of ≤3 cm on chest CT has characteristic manifestations in clinical, imaging and pathology, and there is a statistical difference between thick-walled cavitary lung adenocarcinoma and thin-walled cavitary lung adenocarcinoma.
Interventional cardiologists have traditionally relied upon fluoroscopic imaging for percutaneous coronary interventions. Transcatheter structural heart interventions, however, require additional imaging modalities such as echocardiography and multislice computed tomography (MSCT) for pre-, intra- and post-procedural assistance. During transcatheter structural heart interventions, interventional cardiologists and non-invasive cardiovascular imagers may use different terminologies to describe a certain structure, thus causing misunderstandings within the team. Herein, we present a modality- independent terminology for understanding volumetric images in the context of transcatheter heart valve therapies. The goal of this system is to allow physicians to readily interpret the orientation of fluoroscopic, MSCT, echocardiographic and MRI images, thus generalising their understanding of cardiac anatomy to all imaging modalities.
