CT texture analysis (CTTA) can objectively evaluate the heterogeneity of tissues and their lesions beyond the ability of subjective visual interpretation by extracting the texture features of CT images, then performing analysis and quantitative and objective evaluation, reflecting the tissue micro environmental information. This article reviews the recent studies on the applications of CTTA in gastric cancers, in the aspects of identification of gastric tumors, prediction of stage, correlation with Lauren classification, prediction of occult peritoneal carcinomatosis, evaluation of efficacy and prognosis, and prediction of biomarkers. It is regarded that CTTA has a good application prospect in gastric cancers.
Objective To assess value and limitations of non-invasive methods in assessing liver fibrosis．Methods By summarized current situation and advancement of serum fibrotic markers, ultrasound, CT and MRI in assessing liver fibrosis, we investigated their value and limitations. Results In addition to diagnosis, non-invasive methods of assessing liver fibrosis assess severity of liver fibrosis. For liver fibrosis, however, non-invasive methods can not monitor effectively reaction to therapy and progression. Conclusion Non-invasive methods play important roles in diagnosis and assessing severity of liver fibrosis, and reduce the need of liver biopsy.
ObjectivesTo investigate the influence of scanning parameters (tube voltages and tube currents) on image quality and corresponding radiation doses with simulated lung nodules in chest CT.MethodsThe anthropomorphic chest phantoms with 12 simulated, randomly placed nodules of different diameters and densities in the chest were scanned by different scanning parameters. The detection rate, degree of nodular deformation, image quality (with both subjective and objective evaluation) and the corresponding radiation doses were recorded and evaluated, and the correlation between nodule detection rate, degree of nodular deformation, radiation dose and image quality using different scanning parameters was analyzed.ResultsThe image quality improved with the increase of tube voltage and tube current (P<0.05). When the tube current was constant, the CT values of the vertebral decreased gradually with the increase of tube voltages (P<0.05); however, significant difference was not detected in CT values of the lung field (P>0.05). When the tube current was 100 mAs, the lung nodules with CT values of +100 HU and ?630 HU showed statistical difference when using different tube voltage (P<0.05); but there was no significant difference in nodules of ?800 HU (P=0.57). When tube voltage was 100 kV and 120 kV each, it was possible to detect all lung nodules with a detection rate of 100%. The detection rate was 33% and 66% in 3 mm diameter when the tube current was 80 kV/15 mA and 80 kV/20 mA, respectively. The nodules deformation in nodules with a CT value of ?630 HU and diameter less than 5 mm was the most prominent (P<0.05). After analyzing the relationship between image quality and radiation doses using different tube voltages, we established a system of correlation equations: 80 kV: Y=2.625X+0.038; 100 kV: Y=14.66X+0.158; 120 kV: Y=18.59X+0.093.ConclusionsThe image quality improves with the increase of tube current and tube voltage, as well as the corresponding radiation doses. By reducing the tube voltage and increasing the tube current appropriately, the radiation doses can be reduced. Follow-up CT examination of pulmonary ground glass nodules should apply the same tube voltage imaging parameters, so as to effectively reduce the measurement error of nodule density and evaluate the change of nodules more accurately.
ObjectiveTo discuss the CT imaging differences between mass-forming intrahepatic cholangiocarcinoma (ICC) and poorly-differentiated hepatocellular carcinoma (HCC). MethodThe clinical and CT data of 28 patients with mass-forming ICC (mass-forming ICC group) and 27 patients with poorly-differentiated HCC (poorly-differentiated HCC group), who were confirmed by pathological diagnosis in the West China Hospital from February 2014 to August 2014, were collected and analyzed retrospectively. ResultsThe contour, margin, enhancement patterns in the arterial phase and portal vein phase of the tumor had significant differences between the mass-forming ICC group and poorlydifferentiated HCC group (P < 0.05), in other words, the lobulated shape (15/28, 53.6%), indistinct margin (17/28, 60.7%), peripheral enhancement in the arterial phase (21/28, 75.0%) and prolonged enhancement in the portal vein phase (14/28, 50.0%) were more often seen in the mass-forming ICC group, while the poorly-differentiated HCC group were mainly the round shape (17/27, 63.0%), partially well-defined margin (18/27, 66.7%), diffuse heterogeneous enhancement in arterial phase (20/27, 74.1%) and wash out in the portal vein phase (18/27, 66.7%). The presence of bile duct dilatation in the the mass-forming ICC group was significantly higher than that in the poorly-differentiated HCC group﹝57.1% (16/28) versus 14.8% (4/27), P=0.001﹞. The size and enhancement degree of lymph node in the mass-forming ICC group were significantly bigger or higher than those in the poorly-differentiated HCC group (average lymph node size: 1.7 cm versus 1.3 cm, P=0.009; average enhancement degree of lymph node: 62.6 HU versus 51.8 HU, P=0.031). ConclusionCT features, such as tumor contour, margin, enhancement characteristics, the presence of bile duct dilatation, and the size and enhancement degree of lymph node, might help for differentiating mass-forming ICC from poorly-differentiated HCC, so that more timely selection of appropriate treatment strategies would be made.
Objective To investigate the CT imaging features of hepatic angiomyolipoma and its clinical characteristics. Methods The clinical, radiological, and pathological data of 3 hepatic angiomyolipoma (HAML) patients were retrospectively collected, and the imaging and diagnostic features were analyzed.Results All 3 cases were females, 2 complained of abdominal pain and one was absent of symptom. Both the laboratory examinations were normal in 2 cases, and hepatitis B virus markers were positive in one case. For CT features, the mass located in the superior anterior segment of the right hepatic lobe, in the posterior inferior segment of the right hepatic lobe, and in the left medial lobe, respectively. There were components of fat and soft tissue attenuation in these masses, and in which the CT value of the fat component was from -80 HU to -20 HU (mean -50 HU). There were enhancement in different degree and enhanced vascular imaging could be seen within the lesions. During surgery, all 3 masses were outgrowed from the hepatic lobes. Immunostainning showed HMB45 (+), αSMA (+), S100 (+)，which were bly suggestive of HAML.Conclusion HAML is a rare benign tumor with characteristic CT appearance, and its definite diagnosis relies on the immunohistochemical staining of HMB-45.
The Monte Carlo N-Particle (MCNP) is often used to calculate the radiation dose during computed tomography (CT) scans. However, the physical calculation process of the model is complicated, the input file structure of the program is complex, and the three-dimensional (3D) display of the geometric model is not supported, so that the researchers cannot establish an accurate CT radiation system model, which affects the accuracy of the dose calculation results. Aiming at these two problems, this study designed a software that visualized CT modeling and automatically generated input files. In terms of model calculation, the theoretical basis was based on the integration of CT modeling improvement schemes of major researchers. For 3D model visualization, LabVIEW was used as the new development platform, constructive solid geometry (CSG) was used as the algorithm principle, and the introduction of editing of MCNP input files was used to visualize CT geometry modeling. Compared with a CT model established by a recent study, the root mean square error between the results simulated by this visual CT modeling software and the actual measurement was smaller. In conclusion, the proposed CT visualization modeling software can not only help researchers to obtain an accurate CT radiation system model, but also provide a new research idea for the geometric modeling visualization method of MCNP.
Hemoptysis is a common respiratory emergency, and severe cases can lead to death. Patients with massive hemoptysis need emergency management at the bedside, and fully evaluation for indications and timing of tracheal intubation and transtracheal intervention. When a relatively stable state is achieved, emergency vascular intervention is performed to stop bleeding. CT plays an important role in the risk assessment and interventional treatment of hemoptysis, and it is worthy of clinical promotion and more exploratory research. This article introduces the emergency treatment for massive hemoptysis, the vascular interventional procedure, the exploration of clinical application of preoperative CT, and the clinical application value of CT for hemoptysis risk assessment. It aims to provide a better way to deal with massive hemoptysis and to apply CT to the interventional treatment of hemoptysis more reasonably for clinicians.
Accurate segmentation of ground glass nodule (GGN) is important in clinical. But it is a tough work to segment the GGN, as the GGN in the computed tomography images show blur boundary, irregular shape, and uneven intensity. This paper aims to segment GGN by proposing a fully convolutional residual network, i.e., residual network based on atrous spatial pyramid pooling structure and attention mechanism (ResAANet). The network uses atrous spatial pyramid pooling (ASPP) structure to expand the feature map receptive field and extract more sufficient features, and utilizes attention mechanism, residual connection, long skip connection to fully retain sensitive features, which is extracted by the convolutional layer. First, we employ 565 GGN provided by Shanghai Chest Hospital to train and validate ResAANet, so as to obtain a stable model. Then, two groups of data selected from clinical examinations (84 GGN) and lung image database consortium (LIDC) dataset (145 GGN) were employed to validate and evaluate the performance of the proposed method. Finally, we apply the best threshold method to remove false positive regions and obtain optimized results. The average dice similarity coefficient (DSC) of the proposed algorithm on the clinical dataset and LIDC dataset reached 83.46%, 83.26% respectively, the average Jaccard index (IoU) reached 72.39%, 71.56% respectively, and the speed of segmentation reached 0.1 seconds per image. Comparing with other reported methods, our new method could segment GGN accurately, quickly and robustly. It could provide doctors with important information such as nodule size or density, which assist doctors in subsequent diagnosis and treatment.
Objective To evaluate the feasibil ity and cl inical significance of the computed tomography angiography (CTA) for the latissimus dorsi muscle (LDM) flap transplantation. Methods From September 2007 to August 2008, 3 cases of soft tissue defects in l imbs were treated with LDM flap transplantation. Three patients included 2 males and 1 female whowere 23 to 42 years old. All of soft tissue defects were caused by trauma. The locations were the forearm in 2 cases and the leg in 1 case. The area of defect was 17 cm × 8 cm-20 cm × 10 cm. All cases received CTA to observe the distribution and anastomosis of thoracodorsal artery. Subsequently, three-dimensional computer reconstruction were carried out to display the stereoscopic structure of the LDM flap and to design the LDM flap before operation. Results The anatomy characteristic of LDM flap can be displayed accurately by the three-dimensional reconstruction model. The distribution of thoracodorsal artery in 3 cases of flaps was in concordance with preoperative design completely. All the flaps were excised successfully, the area of the flap was 19 cm × 10 cm-22 cm × 12 cm. All the transferred flaps survived completely. All cases were followed up from 4 months to 12 months. The color and texture of the flaps were good. Conclusion The three-dimensional reconstructive images can provide visible, stereoscopic and dynamic anatomy for cl inical appl ication of LDM flap. The digitized three-dimensional reconstructive models of LDM flap structures can be appl ied in cl inical training and pre-operative design.
ObjectiveTo investigate the significance of 99Tcm-MIBI SPECT dual-phase imaging, B-ultrasound and CT in the diagnosis of primary hyperparathyroidism, and its relationship with the level of serum calcium (CA). MethodsThe clinical data of 73 patients with parathyroid dysfunction (serum parathyroid hormone (PTH) > 130 pg/mL) were retrospectively analyzed. The 99Tcm-MIBI SPECT double phase imaging were performed in 73 cases, 63 cases underwent cervical B-ultrasound examination, and 16 cases underwent CT examination. According to the serum calcium (CA) levels, the patients were divided into CA < 2.7 mmol/L group and CA > 2.7 mmol/L group, and the postoperative pathological examination and followed-up results were as the standard, the sensitivity, specificity, positive predictive value, and negative predictive value of 99Tcm-MIBI SPECT dual-phase imaging, B-ultrasound and CT for diagnosis of PHPT in different serum CA levels were compared. ResultsThe sensitivity of 99Tcm-MIBI SPECT dual-phase imaging, B-ultrasound and CT examination for diagnosis of PHPT was 87.6%, 81.8% and 35.7%, respectively; the specificity was 87.5%, 75.5% and 50.0%, respectively; the positive predictive value was 98.2%, 93.7% and 83.3%, respectively; and the negative predictive value was 46.7%, 33.3% and 10%, respectively. The sensitivity, specificity, positive predictive value and negative predictive value of 99Tcm-MIBI SPECT dual-phase imaging and B-ultrasound examination for diagnosis of PHPT were significantly higher than those of CT examination(P < 0.05). The sensitivity, specificity, positive predictive value and negative predictive value of 99Tcm-MIBI SPECT dual-phase imaging for diagnosis of PHPT were higher than those of B-ultrasound examination, but the difference was not statistically significant (P > 0.05). In the CA < 2.7 mmol/L group, the sensitivity of 99Tcm-MIBI SPECT dual-phase imaging, B-ultrasound and CT examination for diagnosis of PHPT was 91.1%, 84.7% and 37.9%, respectively; the specificity was 80.2%, 72.9% and 49.7%, respectively; the positive predictive value was 96.8%, 96.0% and 79.4%, respectively; and the negative predictive value was 50.0%, 37.5% and 10.0%. In the CA > 2.7 mmol/L group, The sensitivity of 99Tcm-MIBI SPECT dual-phase imaging, B-ultrasound and CT examination for diagnosis of PHPT was 87.9%, 83.9% and 42.8%, respectively; the specificity was 83.3%, 79.2% and 50.0%, respectively; the positive predictive value was 96.9%, 94.1% and 75.0%, respectively; and the negative predictive value was 50.0%, 40.5% and 20.0%. There were no significant difference in the diagnostic accuracy between the 3 methods and the level of serum CV in different levels. ConclusionsThe diagnostic accuracy of 99Tcm-MIBI SPECT dual-phase imaging and B-ultrasound examination for diagnosis of PHPT patients with PTH > 130 pg/mL (especially parathyroid adenoma) were higher than that of CT examination, and it is not associated with the serum CA concentration.