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Objective: To investigate the influence of ECG-triggered technique on imaging quality and parameters in diffusion weighted intravoxel incoherent motion imaging (IVIM DWI). Methods: Twenty young healthy volunteers underwent liver IVIM DWI examination were enrolled, the images were obtained with ECG-triggered and free breath, and SNR, ADC and parameters of IVIM (true-diffusion coefficient [D], pseudo-diffusion coefficient [D*], perfusion fraction [f]) of the left and right lobe of liver were acquired. The scores of liver imaging quality was analyzed with Wilcoxon sign rank sum test. The SNR, ADC, D, D* and f values were analyzed with paired-samples t test. The consistency of ADC, D, D*, and f were assessed with the Bland-Altman method. Results: The scores of liver imaging quality of ECG-triggered were significantly higher than those of free breath (all P<0.01). Under different b values, SNR of left lobe of liver with ECG-triggered were higher than those of the free breath (all P<0.01). The values of ADC and f of left lobe of liver with ECG-triggered were statistically lower than those of free breath (both P<0.05), but the values of D were higher than that of free breath (P<0.05). The consistency of left lobe of liver with ECG-triggered was better than that with free breath. Conclusion: IVIM DWI combined with ECG-triggered can be used to obtain better imaging quality and effectively overcome the interference of heart beating on parameters measuring in left lobe of liver.
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Objective: To explore the setting of the scan mode of prospective electrocardiography (ECG)-gating of spiral CT with 64 slices for the adults with congenital heart disease (CHD) so as to obtain satisfying images and scanning parameters. Methods: 18 adults with CHD were scanned by using spiral CT with 64 slices. The flow rate of contrast agent was 4mL/s, and 20 mL normal saline (NS) was injected after 70 mL contrast agent was injected, and then 15mL contrast agent was injected following with NS, and 25mL NS was used for tracing injection. The prospective ECG-gating and intelligence tracing of contrast agent were adopted to scan. The descending aorta that has same height with crotch of weasand should be chosen as interesting position, and the threshold value was 130 HU, the scan mode of triggering threshold was adopted in the research. The post processing workstation (Philips EBW) was applied to adopt reestablishment of sagittal view, coronal view and axial view, and to carry out reconstruction of 3D multiplanar reformation (MPR), curved planar reformation (CPR), maximum intensity projection (MIP) and volume rendering (VR) so as to observe the situations of heart cavity and peripheral vessel of patients. Results: Each atrium and ventricle has clear construction, and the relationship with peripheral vessel was clearness, and the aortic valve and atrioventicular septum could be observed. And the diagnostic result by using reconstruction technique could be identical with image of Doppler echocardiography. Conclusion: The scan technique of perspective ECG-gating of spiral CT with 64 slices could obtain images, that conformed to requirement of diagnosis and had value, of each atrium, ventricle and peripheral vessel. In the scan, the accurate and suitable parameters, the appropriate dosage and usage of contrast agent, the scan speed, scan time and setting of triggering threshold were the key factors of obtaining image with high quality.
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Objective To investigate the image quality and radiation dosage of the prospective ECG-triggered 256 multi-slice computer tomography (MSCT) angiography in accessing coronary artery (CA) on children.Methods Coronary arteries of ninety-three children were evaluated using prospective ECG-triggered 256-MSCT with the same system setting.Seventy-four patients had the heart rate records and a four-point scoring system was applied to study the capability of MSCT in detecting CA.The signal,noise and contrast-to-noise ratio (CNR) were analyzed to investigate the association of image quality with age (n =74).Then volumetric CT dose index (CTDIvol),dose-length product (DLP) and effective dose (E) were utilized to study the association of radiation dosage with age (n =93).Results On 74 patients with heart records,the detection rate for original,proximal,middle,distal and all 11 segments of CA was 100％,97％,92％,78％ and 91％,respectively.No influence of age was found on their detection (all P＞0.05).E of group A,B,C and D were 1.8,1.3,0.8 and 0.7 mSv,respectively.A strong negative correlation was found between E and age (r =-0.803,P ＜ 0.01).Higher DLP was found on elder patients,though no correlation was found between ages vs.DLP(r =0.124,P ＞ 0.05).No correlation was found between noise vs.age (r =0.041,P ＞ 0.05).Significantly larger signals,CNR and E(t =3.386,2.073,3.825,P ＜ 0.05) were found on younger patients (age ＜ 3 years).Conclusions Prospective ECG-triggered 256-MSCT has considerable performance for the evaluation of coronary arteries on children.However,children under the age of 3 are not recommended for this examinary,but for examination on children ≥ 8-year old,the tube current could be further needed.