Clinical Application Research Of The Second Generation Dual-source Computed Tomography For Diagnosing Complex Cardiovascular Disease

Part I:Clinical application research of the new technique of contrast injection with High-pitch spiral Acqusition by Dual-source Computed Tomography to view complex congenital cardiovascular diseaseBackground and objective:Recently, the clinical application of multi-detector spiral computed tomography (MDCT) in diagnosing for complex congenital cardiovascular disease has been increasing. However,retrospective electrocardiography (ECG)-gated technique was generally adopted. Retrospective ECG-gated spiral CT is widely used for the evaluation of thoracic and cardiovascular deformities in patients with congenital heart disease. Retrospective ECG-gated CT is associated with relatively high radiation dose for its low pitch and overlapping data acquisition although the integration of the dose-saving features of heart rate adaptive pitch and ECG-controlled tube-current modulation can reduce the effective dose for patients with congenital heart disease, higher radiation dose is still the limitation for retrospective ECG-gated CT. Recently, the second generation dual-source CT (DSCT) system has offered a high-pitch spiral mode, data acquisition is also prospectively triggered with the ECG, the radiation dose could been reduced obviously. So, the second generation dual-source CT (DSCT) is called "Green CT". The second question, at present, there hasn’t been an agreed project on contrast injection in dynamic computed tomography to view the congenital heart disease in children, the program of coronary artery CTA was mostly used in patients with congenital heart disease. Before, named "optimization group note technology"---contrast agent and saline is injected separately, contrast agent is injected first, then saline, but the imaging quality was unsatisfactory, either hardening beam artifact in superior vena cava is large, or contrast agent isn’t homogenously distributed Consequently, how to get the pefect image with minimum of contrast agent dosage and lowermost radiation dose on MDCT scanning is one of the hot spot questions that studies currently. This research was to evaluate the technique and method of individuation scanning scheme in Flash CT appling to complex congenital cardiovascular disease.Materials and methods:Forty-three patients (divided into group A and group B) suspected with complex congenital heart disease underwent Flash CTA with optimizing mode and conventional mode. All patients accepted surgical treatment. All icons of cases according to carry on multiple planar reformation(MPR), maximum intensity projection (MIP), curve planar reformation(CPR) and volume rendering(VR) etc. CT image quality, contrast medium dosage and radiation dose were evaluated and the results were carried on statistics analysis.Results:There was no significant difference in diagnostic accuracy (x2=0.384, P=0.594) between group A and group B. All evaluation parameters of image quality were agreed. The CT value in superior vena cava, the right atrium, right ventricle, the main pulmonary artery, left atrium, left ventricle, ascending and the descending aorta in the two groups was statistical significance(P<0.05, respectively). The difference of the CT value between two groups was statistical significance(P=0.000).The image quality of superior vena cava, the right atrium was significantly better in group A than in group B (P<0.05, respectively). The mean effective dose and contrast agent doses in group A was significantly lower (P<0.05) than that in group B.Conclusions:1. We should use the most reasonable method of examination for paitients with complex congenital cardiovascular disease. The image quality, radiation dose and clear diagnosis should be comprehensive considered.2. The prospectively ECG-gated-flash CTA scanning mode is worth extending scanning methods in diagnosis of complex congenital cardiovascular disease because information is not lost under the condition of the radiation dose could been reduced obviously3. Using the new technique of contrast injection, eliminated beam hardening artifact in superior vena cava and right atrium, also lowered the contrast agent dose. It is expected to be widely applied for diagnosis of complex congenital heart disease. Part II:The diagnostic value of new technique of contrast injection with High-pitch spiral Acqusition in complex congenital cardiovascular disease-echocardiographic and surgical results controlsBackground and objective:Echocardiography (ECHO) for the diagnosis of congenital heart disease in clinical has been the initial choice for patients. But multi-detector spiral computed tomography (MDCT) has many years history in diagnosis of complex congenital heart disease and reflects huge advantage. The purpose of this study aims to study the diagnostic accuracy of new technique of contrast injection with High-pitch spiral Acqusition for all the congenital heart disease and compare with the echocardiography and surgical results, then evaluate the diagnostic value of new technique of contrast injection with High-pitch spiral Acqusition for diagnosing complex congenital heart disease and guiding for surgical treatment.Materials and methods:Forty-three patients who were divided into two parts (Conventional group-group A and Optimizing group-groupB) underwent the Flash CT and ECHO examination separately. All the patients accepted surgical treatment and record the size and location of the lesions during operation. The scanning data according to needing to carry on multiple planar reformation(MPR), maximum intensity projeetion(MIP), curve planar reformation(CPR) and volume rendering(VR) etc. Two experienced radiologists analyzed image.Results:All of102lesions of the cardiac anomaly, compared with the surgery results,87lesions were correct and15lesions were incorrect in Flash CT diagnosing. There were99correct lesions and3incorrect lesions in ECHO diagnosing. The diagnosis accuracy of Flash CT and ECHO in diagnosing cardiac anomaly were85.29%(87/102) and97.06%(99/102) respectively, two groups are statistical difference (x2=9.437, P=0.0038). All of69lesions of the cardiovascular fitting and peripheral vascular anomaly,67lesions were correct diagnosis and2lesions were incorrect diagnosis in Flash CT. There were correct diagnosis49lesions and incorrect diagnosis20lesions in ECHO. The accuracy of Flash CT and ECHO in diagnosing cardiovascular fitting and peripheral vascular anomaly were97.10%(67/69) and71.01%(49/69) respectively, the difference of two groups was statistical significant (X2=16.704, P=0.000). The diagnosis accuracy of all the171lesions in Flash CT and ECHO were90.06%(154/171) and87.72%(148/198), the difference was statistical significant (x2=0.095, P=0.567).Conclusions:1. ECHO has been the initial choice for patients with congenital heart disease, because of its superiority in showing intracardiac anatomy and hemodynamic information, it may not be the perfect diagnostic tool because when cardiac anomalies defect lesser, local blood bypass around bigger or not obvious maybe cause the misdiagnosis.2. Axis images is foundation in diagnosing the complex congenital heart disease, find the lesions according to the foundation,then combine with appropriate three-dimensional post-processing reconstruction technique to show the lesions. 3. Flash CT which has fast scanning and high spatial resolution is superior for diagnosing for cardiovascular fitting and heart peripheral vascular anomaly.4. There is no obvious difference in diagnosing for congenital heart disease between Flash CT and ECHO, for peripheral vascular anomaly, Flash CT is better than ECHO,but for cardiac anomalies, ECHO is better than Flash CT.