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[Objective] 1, explore the various types of arrhythmia for dual-source CT coronary angiography image quality analysis of ECG arrhythmia image editing software for quality control. 2, dual-source CT prospective and comparative retrospective ECG-gated coronary CTA image quality and radiation dose subjects analyzed prospectively ECG-gated CT coronary angiography scan mode in use in significance. [Materials and Methods] 1, the choice of the first part of the study: Collection June 2009 - February 2010 between the 51 cases in our hospital coronary CTA arrhythmia patients, all patients scanned data are due to irregular heart rhythm Qi while using ECG editing software processing, comparing before and after treatment of coronary artery image quality evaluation of ECG editing techniques on different arrhythmia image correction application value. 51 patients, aged 36-79 years, median age was about 56 years old. Of which 21 cases of atrial fibrillation, atrial premature beats six cases, a single premature ventricular contractions in 16 cases, 6 cases of frequent premature ventricular contractions, complex arrhythmia two cases. Part II: coronary CTA were prospectively divided into two groups with retrospective ECG-gated coronary CTA scan mode line, forward-looking group of randomly selected 2009.6-2010.2 in our hospital coronary CTA regular rhythm and heart rate lt; 75 beats / min of 39 patients, 32 males and 7 females, aged 25-75 years old, a heart rate of 43-75 beats / min, 2009.6-2010.2 review group was randomly selected in our hospital coronary CTA irregular heart rhythm and heart rate lt; 75 beats / min of 39 patients, 32 males and 7 females, aged 24-72 years old, a heart rate of 37-74 beats / min, case screening criteria: allergy to iodine contrast agents, renal insufficiency, cardiac arrhythmias, heart rate gt; 80 beats / min, respiratory control is poor. 2, equipment and scanning methods Part: Siemens dual-source CT (Siemens Somatom Definition) for scanning. Patient supine, connecting cardiac electrode, the first scan for calcium scoring analysis, scanning parameters: 120kV, 100mAs, collimator width of 64 × 0.6mm, rotation time 0.33s / weeks. Coronary imaging scan parameters: 120kV, 420mAs, arrhythmias automatically select 0.2 pitch, collimator width 64 × 0.6mm. Patients median cubital vein indwelling catheter, using binoculars high-pressure syringe bolus injection of contrast agent Ultravist (370mgI/ml), a flow rate of 5.0-6.5ml / s, the total dose of contrast agent is about 60-80ml, additional physiological saline 25ml, flow rate of 5.0ml / s. Scan range: 1cm to the heart carina diaphragmatic surface, using the contrast agent tracer technique, tracer coronary aortic root surface is scheduled to start a little higher, the trigger threshold 90HU. Part II: Siemens dual-source CT (Siemens Somatom Definition) for scanning. Scan patients divided into A, B groups, A group of prospective group, a prospective ECG-gated scan mode, the scan parameters: 120kV, 371mAs, reconstruction thickness of 0.75mm, collimator width 64 × 0.6mm ; B group review group, the use of retrospective ECG-gated scan, scan parameters: 120kV, 420mAs, collimator width of 64 × 0.6mm, reconstruction thickness of 0.75mm, the two groups were consistent scanning range. Patients median cubital vein indwelling catheter, using binoculars high-pressure syringe bolus injection of contrast agent Ultravist (370mgI/ml), a flow rate of 5.0-6.5ml / s, the total dose of contrast agent is about 60-80ml, additional physiological brine 20ml, flow rate of 5.0ml / s. Scan range: 1cm to the heart carina diaphragmatic surface, using the contrast agent tracer technique, tracer coronary aortic root surface is scheduled to start a little higher, the trigger threshold 90HU. 3, image processing and analysis of the first part: ECG before and after editing original image post-processing workstation in syngo 3D, Circulation and other functions within the window for each cardiac and vascular reconstruction for MIP, CPR, and other post-processing simulation DSA, and to rate the quality of the image before and after editing. ECG editing, first need to rebuild preview window using temporal phase of the best, according to real-time ECG ECG editing. Choose the best phase of the following methods: 1. Relative phase method (in RR interval 0-99% to 5% intervals reconstruction 20 images); 2. Absolute time method (from the R wave after 0msec start 10msec intervals to rebuild the entire RR interval to get multiple images). ECG editing methods are: 1, shift R-peak (R-wave offset); 2, disable Sync (with the exception of waste sync); 3, delete Sync (excluding abnormal synchronous); 4, insert Sync (insert synchronization). For a different take different ECG arrhythmia editing methods, and different types of arrhythmias in patients with ECG edited image for image quality score. According to the American Heart Association, coronary modified scoring method, the image quality using the 0-3 score: 3 points: Vascular clear outline, continuity, and no ladder artifacts; 2 points: Vascular clear outline, continuity is poor, there are few artifacts ; 1 point: Vascular outline clear, poor continuity, a number of ladder-like artifacts, but does not affect the diagnosis; 0: Vascular blurring, poor continuity, artifacts more influence diagnosis. 2 points or more images are excellent, with 0 image quality is poor, not enough to diagnose. Part II: Prospective and retrospective ECG gating original image after scanning incoming post-processing workstation, in 3D, Circulation and other functions within a window right after each blood vessels VR, MIP, CPR and other three-dimensional imaging of the heart and coronary arteries , and the reconstructed image quality score, scoring criteria above, while record Prospective gating and retrospective gating patient dose while scanning parameters: CT dose index volume (volume CT dose index, CTDIvol), dose-length product (dose -length product, DLP) and effective dose (effective dose, ED). ED = DLP × K, that is multiplied by the effective dose is equal to DLP an effective dose coefficient normalized chest (k = 0.014mSv/mGycm). 4, the first part of statistical analysis: Statistical analyzes were performed using SPSS version 13.0 statistical software, statistical methods using paired signed rank test (Wilcoxon Signed Ranks Test) analysis of ECG arrhythmia patients before and after editing the image quality scores, test level a = 0.05, P lt; 0.05 was considered statistically significance. Part II: Statistical analyzes were performed using SPSS statistical software version 13.0, a difference of two clinical data with two independent samples t-test (two independent samples t-test). Prospective and retrospective ECG-gated CT volume dose index (CTDIvol), dose-length product (DLP) and effective dose (effective dose, ED) using two independent samples t test. Significance level a = 0.05, P lt; 0.05 was considered statistically significance. [Results] The first part: 51 cases of cases, there are 21 cases of atrial fibrillation, cardiac coronary image before editing score 0 is divided into 15 cases, one is divided into five cases, two points one case, ECG editing mainly R wave migration will be moved to the top when the signal acquisition phase region, ECG editing images rated 17 cases of three points, two cases of two points, two cases edited ineffective due to the rapid heart rate at 100 beats / points or more; atrial premature beats in 6 cases, 16 cases of single premature ventricular contractions, ECG image before editing coronary score 0 is divided into 18 cases, mostly for the right coronary artery segments appear COSCO split, forming stepped artifacts, a Share of four cases, ECG editing using disable the exception of disuse pulsating signal acquisition, edited 19 cases of patients were able to achieve three points, only three cases of 2 minutes; frequent premature ventricular contractions six cases, ECG before editing are 0, ECG joint insert edit mode using the disable the exception of disuse pulsating signal acquisition and insert a better signal acquisition phase, single or triple the bigeminy abnormal rhythm may be spaced disable pulsating signal acquisition , ECG edited two cases of three points, three cases of two points, one case of 1 minute, after editing is still a cause of respiratory failure due to patient simultaneously with the good; frequent ventricular premature atrial fibrillation in 2 cases, slow or fast heart rate, ventricular premature beats merge two cases, ECG editing using shift disable, ECG was 0 before editing, ECG editing for 2 minutes. ECG before editing the image quality and image quality ECG edited by paired signed rank test (Wilcoxon Signed Ranks Test) after, Z = 6.422, P = 0.000, a statistically significant difference, ECG editing image quality compared to pre-edit improved ECG arrhythmia editing techniques to improve image quality in patients with coronary artery plays a significant role. Part II: prospective group of 39 patients, 2 cases cause image artifacts heart rate fluctuations affect the observed poor, and the remaining 46 patients were shown 578 segments, of which 43 segments because of the small blood vessels are not included in the statistical analysis, and the remaining 578 segments can meet the requirements of the clinical diagnosis; review group, 2 patients with poor breathing, three cases of severe coronary calcification result in poor images affect the observed, and the remaining 43 patients with 523 segments can meet the requirements of the clinical diagnosis. Two groups of patients in the evaluation of image quality was no significant difference, t = 0.843, P = 0.090 gt; 0.05. Prospects effective radiation dose group (4.41 ± 0.476) mSv, recalled an effective radiation dose group (17.66 ± 3.30) mSv, with t = 23.655, P = 0.000, the difference was statistically significant; prospective group CTDIvol was (23.57 ± 0.072) mGy, review group CTDIvol was (79.44 ± 14.75) mGy, with t = 24.813, P = 0.000, the difference was statistically significant; DLP prospective group was (315.36 ± 33.977) mGy. cm, DLP review group was (1261.46 ± 235.68) mGy. cm, with t = 24.813, P = 0.000, the difference was statistically significant. [Conclusion] The first part: ECG editing function makes use of more and more patients with mild arrhythmia can be used noninvasive coronary artery widened the part of the patient examination arrhythmia indications; For occasional premature ventricular contractions , atrial premature beats, atrial fibrillation, sinoatrial block, ECG editing techniques to improve the quality of the image can play a significant role; For frequent premature ventricular contractions, complex arrhythmias, severe loss due to the image signal, ECG editing more difficult to make the image perfect, but improvements can still play a role. Part II: For the neat rhythm in patients with prospective ECG-gated scan mode with retrospective ECG-gated scan was no significant difference in image quality, but the former was significantly lower effective radiation dose. Therefore, compared with retrospective gating patients prospectively gated coronary CTA effectively reduce the radiation dose.
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