Objective To observe value of 0D-1D coupling model and 3D fluid-structure interaction(FSI)model based on coronary CT angiography(CCTA)for displaying hemodynamic characteristics of coronary artery stenosis.Methods Base...Objective To observe value of 0D-1D coupling model and 3D fluid-structure interaction(FSI)model based on coronary CT angiography(CCTA)for displaying hemodynamic characteristics of coronary artery stenosis.Methods Based on CCTA data of the stenosed left anterior descending branch(LAD)in a patient with coronary heart disease,an 0D-1D coupling model and 3D FSI model were built,respectively.Then hemodynamic characteristic indexes,including the pressure,flow velocity and wall shear stress(WSS)were obtained in every 0.01 s during 1 s at 5 sampling points(i.e.sampling point 1—5)using these 2 models,respectively,and the consistencies of the results between models were evaluated with Spearman correlation coefficient r s.Results The time consuming for construction of 0D-1D coupling model and 3D FSI model was 0.033 min and 704 min,respectively.Both models showed basically distribution of the pressure,flow velocity and WSS of the stenosed LAD.For more details,the pressure at the stenosed segment of LAD and the proximal segment of stenosis were both higher,which gradually decreased at the distal segment of stenosis,and the flow velocity at the proximal segment of stenosis was in a relatively slow and uniform condition,with significantly increased flow velocity and WSS at the stenosed segment.Compared with 3D FSI model,0D-1D vascular coupling model was relatively unrefined and lack of distal flow lines when displaying blood flow velocity.For sampling point 2 at the stenosed segment of LAD,no significant consistency for pressure between 2 models was found(P=0.118),but strong consistency for the flow velocity and WSS(r s=0.730,0.807,both P<0.05).The consistencies of pressure,flow velocity and WSS between 2 models at the proximal and distal segment of stenosis,i.e.1,3—5 sampling points were week to moderate(r s=0.237—0.669,all P<0.05).Conclusion 0D-1D coupling model exhibited outstanding computational efficiency and might provide relatively reasonable results,while 3D FSI model showed higher accuracy for details and streamline when simulating LAD stenosis.展开更多
The role of 16-slice spiral CT was selective X-ray coronary angiography （SCA） who were suspected of having coronary heart evaluated in the diagnosis of coronary stenosis, with serving as the reference standard. Sixt...The role of 16-slice spiral CT was selective X-ray coronary angiography （SCA） who were suspected of having coronary heart evaluated in the diagnosis of coronary stenosis, with serving as the reference standard. Sixty-five patients disease, without percutaneous transluminal coronary angioplasty or coronary bypass-grafting, were investigated using 16-slice CT. Eight patients with pre-scan heart rate of more than 80 beats/min were given β-blockers. After the retrospectively ECG-gated axial imaging reconstruction, volume redering （VR）, multi-planar reconstruction （MPR）, curved MPR and maximum intensity projection （MIP） were used to reconstruct. Every segment of coronary artery with a diameter ≥1.5 mm was assessed, and the presence on CT with a stenosis exceeding 50 % diameter reduction was compared with that on SCA. The reasons which lead to some segments unevaluable were analysed. Compared with SCA, 93 % coronary segments and 94 % main branches were evaluable. Residual cardiac motion artifacts, severe calcification and poor opacification made 58 %, 28 % and 14 % of the remaining 60 segments unevaluable respectively. Without routine administration of β-blockers, good coronary imaging quality can be acquired using 16-slice spiral CT. It is a reliable noninvasive method for detection of obstructive coronary artery disease.展开更多
To evaluate the value of 16-slice spiral CT in the demonstration of coronary artery and in the diagnose of coronary artery stenosis. Methods Plain and enhanced CT scans were performed with a 16-slice CT scanner (Sensa...To evaluate the value of 16-slice spiral CT in the demonstration of coronary artery and in the diagnose of coronary artery stenosis. Methods Plain and enhanced CT scans were performed with a 16-slice CT scanner (Sensation 16, Siemens, Germany) in 230 patients with suspected coronary heart disease (CHD). Parameters of the plain scan were: 120 kV, 133 mA, slice col-limation 16 mm×1.5 mm, rotation time 0.42 seconds, increment 1.5 mm, and slice width 3 mm. Parameters of the enhanced scan were: 120 kV, 500 mA, slice collimation 16 mm×0.75 mm, rotation time 0.42 seconds, increment 0.5 mm, and slice width 1 mm. Enhanced CT scan was performed with a rapid intravenous injection of 100 mL iothalamate meglumine (Ultravist) (370 mgI/mL) or Omnipaque (350 mgI/mL) and 30 mL 0.9% NaCl chaser bolus at a flow rate of 3.5 mL/s. Calcium scoring with plain scan images and two and three dimensional reconstruction with enhanced scan images were made in all cases, among which 30 cases underwent conventional coronary angiography. Demonstration of coronary arteries and their stenosis were evaluated and the factors that might influence the image quality were analyzed. Results Coronary calcium scores were calculated and coronary artery was demonstrated in our study. In the evaluationof image quality with volume rendering technique (VRT) images, 78.3% of the images were of the first class, 12.2% the sec-ond class, and 9.6% the third class. Multi-planar reconstruction (MPR) and maximal intensity projection (MIP) were better than VRT in the demonstration of small branches. The image quality was related to the heart rate, with or without arrhythmia, and breath-hold ability of patients. Comparative study of the stenosis of coronary arteries in 30 cases showed that the sensi-tivity and specificity of 16-slice coronary CT angiography (CTA) to diagnose significant stenosis were 95.8% and 94.8% resp-ectively. Conclusion As a non-invasive and quick method, 16-slice coronary CTA is sensitive and specific to diagnose the stenosis of coronary arteries and can be used as a screening method in the diagnosis of CHD.展开更多
Background Noninvasive cardiac imaging is now central to the diagnosis and management of patients with moderate probability for coronary artery disease. The aim of this study was to assess the impact of stress myocard...Background Noninvasive cardiac imaging is now central to the diagnosis and management of patients with moderate probability for coronary artery disease. The aim of this study was to assess the impact of stress myocardial perfusion single photon emission computerized tomography （SPECT） on in-hospital coronary angiography and revascularization for such patients. Methods Between January 2005 and June 2007, 1053 consecutive in-hospital patients （423 women,展开更多
Background Invasive intravascular ultrasound （IVUS） is current diagnostic standard for myocardial bridging （MB）. Non-invasive multislice computerized tomography coronary angiography （MSCT） technique has provided...Background Invasive intravascular ultrasound （IVUS） is current diagnostic standard for myocardial bridging （MB）. Non-invasive multislice computerized tomography coronary angiography （MSCT） technique has provided a good anatomical view of the tunnel artery now. Methods A total of 51 consecutive patients with atypical or typical angina scheduled for IVUS were enrolled in this study and MSCT was performed 7 days before IVUS. Coronary imaging was quantified using IVUS and MSCT. Four main vessels （left main artery （LMA）, left anterior descending （LAD）, left circumflex （LCX）, right coronary artery （RCA）） were examined. Results Forty-one out of 51 （80%） patients received metaprolol （25 mg） before the MSCT scan and 25 of them were current beta-blocker users. The mean heart rate was （64_＋3） beats per minute. A total of 51 patients underwent IVUS examination （30 with MB and 21 without MB） were chosen for this study. Twenty-eight out of 30 MB cases were correctly diagnosed by MSCT and 2 patients with MB were not detected. Comparison with IVUS, the sensitivity of detection by MSCT was 93%, specificity was 100%. The lumen diameter of the tunnel artery derived from MSCT and IVUS significantly decreased from （2.9±0.3） mm to （2.4±0.4） mm （P〈0.001） and from （3.3±0.3） mm to （2.6±0.5） mm （P〈0.001）, respectively. Minimal and maximal diameters of MB derived from MSCT were significantly smaller than those from IVUS （（2.4±0.4） mm vs （2.6±0.5） mm, P〈0.05 and （2.9±0.3） mm vs （3.3±0.3） mm, P〈0.05）, respectively. Conclusions MSCT offers a reliable non-invasive method for MB in LAD and atherosclerosis diagnosis with diagnostic accuracy comparable with invasive IVUS.展开更多
Background In-stent restenosis is a common complication after stent implantation. However, the assessment of stent lumen in computed tomography （CT） coronary angiography is limited by multiple factors. Our study aim...Background In-stent restenosis is a common complication after stent implantation. However, the assessment of stent lumen in computed tomography （CT） coronary angiography is limited by multiple factors. Our study aimed to evaluate the accuracy and the suspected affecting factors in diagnosing coronary in-stent restenosis by dual-source CT （DSCT） compared with coronary angiography. Methods One hundred and fifteen stents in 50 patients were evaluated with DSCT before coronary angiography for the detection of coronary in-stent restenosis （〉 50% luminal narrowing）. Patency of each stent was analyzed by two independent expert radiologists blinded to the results of coronary angiography. The relationship between diagnostic accuracy and the suspected factors including age, body mass index （BMI）, heart rate, variation of heart rate, radiation dose, image quality, location and stent characteristics （type, material, diameter, length and strut thickness） was assessed with both univariate and multivariate analysis. The fitting of a Logistic regression model was evaluated using a receiver operating characteristic （ROC） curve. Results Mean stent diameter was （2.9±0.4） mm. Sensitivity, specificity, positive and negative predictive values and accuracy of DSCT in detection of in-stent restenosis were 69.2%, 91.2%, 50.0%, 95.9%, and 88.7%, respectively. In a subgroup of stents with a diameter 〉3.0 mm, sensitivity, specificity, positive and negative predictive values and accuracy were 100.0%, 96.5%, 75.0%, 100.0%, and 96.8%, respectively. Stent diameter 〈3.0 mm and poor image quality were associated with poor diagnostic accuracy （P 〈0.05）. The area under curve of ROC was 0.79. Conclusion DSCT can provide high accuracy for the assessment of in-stent restenosis in stents with a diameter 〉3.0 mm, and can play an important role in ruling out in-stent restenosis.展开更多
Objective： To investigate the diagnostic value of computerized tomographic angiography （ CTA ） and magnetic resonance angiography （ MRA ） for intracranial traumatic aneurysms （TAs）. Methods： CTA and MRA of si...Objective： To investigate the diagnostic value of computerized tomographic angiography （ CTA ） and magnetic resonance angiography （ MRA ） for intracranial traumatic aneurysms （TAs）. Methods： CTA and MRA of six patients with intracranial TAs verified by digital subtraction angiography （DSA） and surgery were retrospectively analysed. All patients were examined by nonenhanced computerized tomography （CT） and two by CTA. The source data were reconstructed by volume rendering （VR） and multi-planar reconstruction （MPR） from CTA. Four of them had maxhnum intensity project （MIP） from MRA. Results ： Of the six patients, a total of seven TAs were detected by CTA and MRA examinations. Five cases had only one TA and one case had two TAs. The average diameter was 2.3 cm （1.1-3.3 cm）. CTA demonstrated two TAs appeared at the cavernous segment of the internal carotid artery （ICA） and the middle cerebral artery （MCA） respectively. MCA TA was definitely and dearly demonstrated on VR images, whereas VR images failed to depict the cavernous ICA TA, which was detected on MPR images. Two TAs were found irregular saccular shape,irregular margin of parent artery and wide neck on CTA. Four MRA examinations demonstrated five TAs, including the cavernous segment ICA TAs （2 cases）, the supraclinoid segment ICA TA （1 case ）, and the cavernous segment associated with opposite side of the petrosal segment ICA TA （1 case）. In a cavernous ICA TA, MRA only revealed aneurysm body, whereas aneurysm neck and distal segment of the parent artery were not revealed. In the remaining cases, MRA clearly depicted aneurysm body and parent artery, whereas the neck was not displayed. ICA TAs showed irregular capsnle-like high signal intensity on MRA images. Four TAs exhibited irregular distal segment of the parent artery. TAs at the supraclinoid segment or MCA failed to find fracture signs on nonenhanced CT. Conclusions： Both CTA and MRA examinations are the effective non-invasive method of imageology for diagnosing intracranlal TAs, while CTA is more eligible for diagnosing TAs after nonenhanced CT has demonstrated skull base fractures.展开更多
文摘Objective To observe value of 0D-1D coupling model and 3D fluid-structure interaction(FSI)model based on coronary CT angiography(CCTA)for displaying hemodynamic characteristics of coronary artery stenosis.Methods Based on CCTA data of the stenosed left anterior descending branch(LAD)in a patient with coronary heart disease,an 0D-1D coupling model and 3D FSI model were built,respectively.Then hemodynamic characteristic indexes,including the pressure,flow velocity and wall shear stress(WSS)were obtained in every 0.01 s during 1 s at 5 sampling points(i.e.sampling point 1—5)using these 2 models,respectively,and the consistencies of the results between models were evaluated with Spearman correlation coefficient r s.Results The time consuming for construction of 0D-1D coupling model and 3D FSI model was 0.033 min and 704 min,respectively.Both models showed basically distribution of the pressure,flow velocity and WSS of the stenosed LAD.For more details,the pressure at the stenosed segment of LAD and the proximal segment of stenosis were both higher,which gradually decreased at the distal segment of stenosis,and the flow velocity at the proximal segment of stenosis was in a relatively slow and uniform condition,with significantly increased flow velocity and WSS at the stenosed segment.Compared with 3D FSI model,0D-1D vascular coupling model was relatively unrefined and lack of distal flow lines when displaying blood flow velocity.For sampling point 2 at the stenosed segment of LAD,no significant consistency for pressure between 2 models was found(P=0.118),but strong consistency for the flow velocity and WSS(r s=0.730,0.807,both P<0.05).The consistencies of pressure,flow velocity and WSS between 2 models at the proximal and distal segment of stenosis,i.e.1,3—5 sampling points were week to moderate(r s=0.237—0.669,all P<0.05).Conclusion 0D-1D coupling model exhibited outstanding computational efficiency and might provide relatively reasonable results,while 3D FSI model showed higher accuracy for details and streamline when simulating LAD stenosis.
文摘The role of 16-slice spiral CT was selective X-ray coronary angiography （SCA） who were suspected of having coronary heart evaluated in the diagnosis of coronary stenosis, with serving as the reference standard. Sixty-five patients disease, without percutaneous transluminal coronary angioplasty or coronary bypass-grafting, were investigated using 16-slice CT. Eight patients with pre-scan heart rate of more than 80 beats/min were given β-blockers. After the retrospectively ECG-gated axial imaging reconstruction, volume redering （VR）, multi-planar reconstruction （MPR）, curved MPR and maximum intensity projection （MIP） were used to reconstruct. Every segment of coronary artery with a diameter ≥1.5 mm was assessed, and the presence on CT with a stenosis exceeding 50 % diameter reduction was compared with that on SCA. The reasons which lead to some segments unevaluable were analysed. Compared with SCA, 93 % coronary segments and 94 % main branches were evaluable. Residual cardiac motion artifacts, severe calcification and poor opacification made 58 %, 28 % and 14 % of the remaining 60 segments unevaluable respectively. Without routine administration of β-blockers, good coronary imaging quality can be acquired using 16-slice spiral CT. It is a reliable noninvasive method for detection of obstructive coronary artery disease.
文摘To evaluate the value of 16-slice spiral CT in the demonstration of coronary artery and in the diagnose of coronary artery stenosis. Methods Plain and enhanced CT scans were performed with a 16-slice CT scanner (Sensation 16, Siemens, Germany) in 230 patients with suspected coronary heart disease (CHD). Parameters of the plain scan were: 120 kV, 133 mA, slice col-limation 16 mm×1.5 mm, rotation time 0.42 seconds, increment 1.5 mm, and slice width 3 mm. Parameters of the enhanced scan were: 120 kV, 500 mA, slice collimation 16 mm×0.75 mm, rotation time 0.42 seconds, increment 0.5 mm, and slice width 1 mm. Enhanced CT scan was performed with a rapid intravenous injection of 100 mL iothalamate meglumine (Ultravist) (370 mgI/mL) or Omnipaque (350 mgI/mL) and 30 mL 0.9% NaCl chaser bolus at a flow rate of 3.5 mL/s. Calcium scoring with plain scan images and two and three dimensional reconstruction with enhanced scan images were made in all cases, among which 30 cases underwent conventional coronary angiography. Demonstration of coronary arteries and their stenosis were evaluated and the factors that might influence the image quality were analyzed. Results Coronary calcium scores were calculated and coronary artery was demonstrated in our study. In the evaluationof image quality with volume rendering technique (VRT) images, 78.3% of the images were of the first class, 12.2% the sec-ond class, and 9.6% the third class. Multi-planar reconstruction (MPR) and maximal intensity projection (MIP) were better than VRT in the demonstration of small branches. The image quality was related to the heart rate, with or without arrhythmia, and breath-hold ability of patients. Comparative study of the stenosis of coronary arteries in 30 cases showed that the sensi-tivity and specificity of 16-slice coronary CT angiography (CTA) to diagnose significant stenosis were 95.8% and 94.8% resp-ectively. Conclusion As a non-invasive and quick method, 16-slice coronary CTA is sensitive and specific to diagnose the stenosis of coronary arteries and can be used as a screening method in the diagnosis of CHD.
文摘Background Noninvasive cardiac imaging is now central to the diagnosis and management of patients with moderate probability for coronary artery disease. The aim of this study was to assess the impact of stress myocardial perfusion single photon emission computerized tomography （SPECT） on in-hospital coronary angiography and revascularization for such patients. Methods Between January 2005 and June 2007, 1053 consecutive in-hospital patients （423 women,
文摘Background Invasive intravascular ultrasound （IVUS） is current diagnostic standard for myocardial bridging （MB）. Non-invasive multislice computerized tomography coronary angiography （MSCT） technique has provided a good anatomical view of the tunnel artery now. Methods A total of 51 consecutive patients with atypical or typical angina scheduled for IVUS were enrolled in this study and MSCT was performed 7 days before IVUS. Coronary imaging was quantified using IVUS and MSCT. Four main vessels （left main artery （LMA）, left anterior descending （LAD）, left circumflex （LCX）, right coronary artery （RCA）） were examined. Results Forty-one out of 51 （80%） patients received metaprolol （25 mg） before the MSCT scan and 25 of them were current beta-blocker users. The mean heart rate was （64_＋3） beats per minute. A total of 51 patients underwent IVUS examination （30 with MB and 21 without MB） were chosen for this study. Twenty-eight out of 30 MB cases were correctly diagnosed by MSCT and 2 patients with MB were not detected. Comparison with IVUS, the sensitivity of detection by MSCT was 93%, specificity was 100%. The lumen diameter of the tunnel artery derived from MSCT and IVUS significantly decreased from （2.9±0.3） mm to （2.4±0.4） mm （P〈0.001） and from （3.3±0.3） mm to （2.6±0.5） mm （P〈0.001）, respectively. Minimal and maximal diameters of MB derived from MSCT were significantly smaller than those from IVUS （（2.4±0.4） mm vs （2.6±0.5） mm, P〈0.05 and （2.9±0.3） mm vs （3.3±0.3） mm, P〈0.05）, respectively. Conclusions MSCT offers a reliable non-invasive method for MB in LAD and atherosclerosis diagnosis with diagnostic accuracy comparable with invasive IVUS.
文摘Background In-stent restenosis is a common complication after stent implantation. However, the assessment of stent lumen in computed tomography （CT） coronary angiography is limited by multiple factors. Our study aimed to evaluate the accuracy and the suspected affecting factors in diagnosing coronary in-stent restenosis by dual-source CT （DSCT） compared with coronary angiography. Methods One hundred and fifteen stents in 50 patients were evaluated with DSCT before coronary angiography for the detection of coronary in-stent restenosis （〉 50% luminal narrowing）. Patency of each stent was analyzed by two independent expert radiologists blinded to the results of coronary angiography. The relationship between diagnostic accuracy and the suspected factors including age, body mass index （BMI）, heart rate, variation of heart rate, radiation dose, image quality, location and stent characteristics （type, material, diameter, length and strut thickness） was assessed with both univariate and multivariate analysis. The fitting of a Logistic regression model was evaluated using a receiver operating characteristic （ROC） curve. Results Mean stent diameter was （2.9±0.4） mm. Sensitivity, specificity, positive and negative predictive values and accuracy of DSCT in detection of in-stent restenosis were 69.2%, 91.2%, 50.0%, 95.9%, and 88.7%, respectively. In a subgroup of stents with a diameter 〉3.0 mm, sensitivity, specificity, positive and negative predictive values and accuracy were 100.0%, 96.5%, 75.0%, 100.0%, and 96.8%, respectively. Stent diameter 〈3.0 mm and poor image quality were associated with poor diagnostic accuracy （P 〈0.05）. The area under curve of ROC was 0.79. Conclusion DSCT can provide high accuracy for the assessment of in-stent restenosis in stents with a diameter 〉3.0 mm, and can play an important role in ruling out in-stent restenosis.
文摘Objective： To investigate the diagnostic value of computerized tomographic angiography （ CTA ） and magnetic resonance angiography （ MRA ） for intracranial traumatic aneurysms （TAs）. Methods： CTA and MRA of six patients with intracranial TAs verified by digital subtraction angiography （DSA） and surgery were retrospectively analysed. All patients were examined by nonenhanced computerized tomography （CT） and two by CTA. The source data were reconstructed by volume rendering （VR） and multi-planar reconstruction （MPR） from CTA. Four of them had maxhnum intensity project （MIP） from MRA. Results ： Of the six patients, a total of seven TAs were detected by CTA and MRA examinations. Five cases had only one TA and one case had two TAs. The average diameter was 2.3 cm （1.1-3.3 cm）. CTA demonstrated two TAs appeared at the cavernous segment of the internal carotid artery （ICA） and the middle cerebral artery （MCA） respectively. MCA TA was definitely and dearly demonstrated on VR images, whereas VR images failed to depict the cavernous ICA TA, which was detected on MPR images. Two TAs were found irregular saccular shape,irregular margin of parent artery and wide neck on CTA. Four MRA examinations demonstrated five TAs, including the cavernous segment ICA TAs （2 cases）, the supraclinoid segment ICA TA （1 case ）, and the cavernous segment associated with opposite side of the petrosal segment ICA TA （1 case）. In a cavernous ICA TA, MRA only revealed aneurysm body, whereas aneurysm neck and distal segment of the parent artery were not revealed. In the remaining cases, MRA clearly depicted aneurysm body and parent artery, whereas the neck was not displayed. ICA TAs showed irregular capsnle-like high signal intensity on MRA images. Four TAs exhibited irregular distal segment of the parent artery. TAs at the supraclinoid segment or MCA failed to find fracture signs on nonenhanced CT. Conclusions： Both CTA and MRA examinations are the effective non-invasive method of imageology for diagnosing intracranlal TAs, while CTA is more eligible for diagnosing TAs after nonenhanced CT has demonstrated skull base fractures.
