320排CT冠状动脉血管成像与冠状动脉造影评估冠状动脉支架内再狭窄程度的对比分析

目的评价320排CT冠状动脉血管成像(CCTA)在冠状动脉支架内再狭窄评估中的临床应用价值。方法以选择性冠状动脉造影(CAG)为金标准,应用320排CCTA评价100例患者冠状动脉支架内再狭窄的程度。将冠状动脉支架内管径分为无狭窄、轻度狭窄(≤50%)、中度狭窄(51%～75%)和重度狭窄或闭塞(76%～100%)4个等级,分析320排CCTA与CAG评估狭窄程度的一致性。其中再狭窄≥50%为阳性,包括支架内及支架两端5mm范围内的血管段。统计学方法采用Kappa评价方法。结果 100例患者中共评价分析175枚支架,CAG示冠状动脉支架内再狭窄44枚,320排CCTA正确诊断42枚,漏诊2枚,误诊10枚,敏感度为95.45%、特异度为92.37%、准确度为70.29%、阳性预测值为80.77%、阴性预测值为98.37%。在P<0.05的检验标准上,Kappa值为0.5688,320排CCTA和CAG对支架内狭窄程度评估一致性好。结论 320排CCTA能够准确显示支架内再狭窄的部位及程度,而且无创、重复性好,图像直观可信,具有很高的临床应用价值。     

Transthoracic Doppler assessment of coronary flow velocity reserve in children with Kawasaki disease: comparison with coronary angiography and thallium-201 imaging

OBJECTIVES: The purpose of this study was to determine the feasibility of coronary flow velocity reserve (CFVR) measurement by transthoracic Doppler echocardiography (TTDE) in children with Kawasaki disease (KD). BACKGROUND: Doppler-derived CFVR is a reliable marker predicting the presence of myocardial ischemia. METHODS: We studied 49 patients (median age 11 years) with KD. The CFVR was calculated as the ratio of hyperemic to basal peak (peak CFVR) and mean (mean CFVR) diastolic flow velocities in the posterior descending coronary artery (PD) and left anterior descending coronary artery (LAD). The CFVR measurements by TTDE were compared with the results of coronary angiography, thallium-201 (Tl-201) single-photon emission computed tomography (SPECT), and intracoronary Doppler study. RESULTS: The CFVR measurements by TTDE were obtained in 92 (94%) of 98 vessels of the PD and LAD in 49 study patients. Both peak and mean CFVRs for 21 stenotic vessels were significantly smaller than those for 35 normal vessels and for 20 vessels with aneurysmal lesions (p < 0.0001). Peak and mean CFVR <2.0 predicted significant coronary stenosis, as determined by coronary angiography, with sensitivities and specificities of 89% and 96% and 89% and 97%, respectively. Also, both peak and mean CFVRs were correlated with reversible perfusion defects on Tl-201 SPECT (agreement 80%; kappa 0.4). The correlation between peak and mean CFVRs determined by the TTDE and intracoronary Doppler studies in 36 vessels of 23 patients were 0.76 and 0.80, respectively. CONCLUSIONS: The CFVR measured by TTDE predicts the presence of significant coronary stenosis of either the right coronary artery or LAD, as well as myocardial ischemia of these territories in children with KD.     

Noninvasive assessment of significant right coronary artery stenosis based on coronary flow velocity reserve in the right coronary artery by transthoracic Doppler echocardiography

BACKGROUND: Coronary flow velocity reserve (CFVR) measured by transthoracic Doppler echocardiography (TTDE) has been reported to be useful for the noninvasive assessment of coronary stenosis in the left anterior descending artery. However, the measurement of CFVR in the right coronary artery by TTDE has not yet been validated in a clinical study. OBJECTIVE: The aim of this study was to evaluate whether CFVR by TTDE can detect significant stenosis in the right coronary artery. METHODS: We studied 50 patients who underwent coronary angiography. Coronary flow velocity in the posterior descending branch of the right coronary artery (PD) was measured by TTDE both at baseline and during hyperemia induced by the intravenous infusion of adenosine triphosphate. CFVR was calculated as the hyperemia/baseline (average diastolic peak velocity). RESULTS: Adequate spectral Doppler recordings in the PD were obtained in 36 patients including 26 patients who were given an echocardiographic contrast agent to improve Doppler spectral signals. The study population was divided into 2 groups with (Group A;n = 11) and without (Group B;n = 25) significant stenosis in the right coronary artery. CFVR in Group A was significantly smaller than that in Group B (1.6+/-0.3versus2.5+/-0.4; P < 0.0001). The sensitivity of a CFVR of <2.0 for predicting the presence of significant stenosis in the right coronary artery was 91%, and the specificity was 88%. CONCLUSIONS: The measurement of CFVR in the PD by TTDE is useful for the noninvasive assessment of significant stenosis in the right coronary artery.     

Noninvasive coronary flow velocity reserve measurement in the posterior descending coronary artery for detecting coronary stenosis in the right coronary artery using contrast-enhanced transthoracic Doppler echocardiography

BACKGROUND: Coronary flow velocity reserve (CFVR) measurement by transthoracic Doppler echocardiography (TTDE) has been found to be useful for assessing left anterior descending coronary artery (LAD) stenosis. However, this method has been restricted only for the LAD. The purpose of this study was to detect severe right coronary artery (RCA) stenosis by CFVR measurement using contrast-enhanced TTDE. METHODS: In 60 consecutive patients with angina pectoris (mean (SD) age: 60 (11), 18 women), coronary flow velocities in the RCA were recorded in the postero-descending coronary artery by contrast-enhanced TTDE at rest and during hyperemia induced by intravenous infusion of adenosine triphosphate (140 mcg/ml/kg). CFVR was calculated as the ratio of hyperemic to basal peak and mean diastolic flow velocity. CFVR measurements by TTDE were compared with the results of coronary angiography performed within 1 week. RESULTS: Coronary flow velocity was successfully recorded in 49 (82%) of the 60 patients with contrast agent. CFVR (mean (SD)) was 1.4 (0.4) in patients with, and 2.6 (0.6) in patients without significant stenosis in the RCA (%diameter stenosis > 75%, P < 0.001). Using the cutoff value 2.0 for CFVR in the RCA, its sensitivity and specificity in detecting significant stenosis in the RCA were 88% and 91%, respectively. CONCLUSION: CFVR measurement in the postero-descending coronary artery by contrast enhanced TTDE is a new, noninvasive method to detect significant stenosis in the RCA.     

Diagnostic accuracy of coronary in-stent restenosis using 64-slice computed tomography: comparison with invasive coronary angiography.

OBJECTIVES: This study sought to evaluate the diagnostic accuracy of coronary binary in-stent restenosis (ISR) with angiography using 64-slice multislice computed tomography coronary angiography (CTCA) compared with invasive coronary angiography (ICA). BACKGROUND: A noninvasive detection of ISR would result in an easier and safer way to conduct patient follow-up. METHODS: We performed CTCA in 81 patients after stent implantation, and 125 stented lesions were scanned. Two sets of images were reconstructed with different types of convolution kernels. On CTCA, neointimal proliferation was visually evaluated according to luminal contrast attenuation inside the stent. Lesions were graded as follows: grade 1, none or slight neointimal proliferation; grade 2, neointimal proliferation with no significant stenosis (<50%); grade 3, neointimal proliferation with moderate stenosis (> or =50%); and grade 4, neointimal proliferation with severe stenosis (> or =75%). Grades 3 and 4 were considered binary ISR. The diagnostic accuracy of CTCA compared with ICA was evaluated. RESULTS: By ICA, 24 ISRs were diagnosed. Sensitivity, specificity, positive predictive value, and negative predictive value were 92%, 81%, 54%, and 98% for the overall population, whereas values were 91%, 93%, 77%, and 98% when excluding unassessable segments (15 segments, 12%). For assessable segments, CTCA correctly diagnosed 20 of the 22 ISRs detected by ICA. Six lesions without ISR were overestimated as ISR by CTCA. As the grade of neointimal proliferation by CTCA increases, the median value of percent diameter stenosis increased linearly. CONCLUSIONS: Binary ISR can be excluded with high probability by CTCA, with a moderate rate of false-positive results.     

Non-invasive computed tomography angiography in the assessment of coronary stent patency: an Australian experience

Background: This study aimed to evaluate the feasibility and accuracy of 16‐slice computed tomography (CT) in the assessment of coronary stent patency. CT coronary angiography (CA) has a high degree of accuracy in the assessment of coronary artery disease compared with invasive selective CA. However, its accuracy in the evaluation of stent patency is not well investigated. Methods: We conducted a retrospective observational study of paired CT coronary angiography (CT–CA) and invasive fluoroscopic coronary angiography (FCA) in 37 patients with 47 coronary stents. CT–CA was carried out with an electrocardiogram‐gated 16‐slice CT (LightSpeed‐16, General Electric (GE), WI, USA). Two CT reporters, blinded to the FCA findings, assessed CT images for stent patency. A cardiologist blinded to CT findings reported FCA. FCA was regarded as the reference standard. Results: A CT–CA could assess 45 of 47 coronary stents (96%). Non‐assessable stents on CT–CA were due to motion artefacts and stent‐blooming effects. Of those 45 assessable stents, CT–CA correctly identified five out of seven stents with binary in‐stent restenosis (ISR) and 37 of 38 stents without binary ISR. The sensitivity and specificity of 16‐slice CT in the evaluation of coronary stents for binary ISR were 71% (95% confidence interval (CI) (29%, 96%)) and 97% (95%CI (86%, 100%)), respectively, exclusive of non‐assessable stents. The positive and negative predictive values of 16‐slice CT were 83% (95%CI (36%, 100%)) and 95% (95%CI (83%, 99%)), respectively. Conclusion: Sixteen‐slice CT has a low sensitivity, but very a high specificity when compared with FCA in the evaluation of coronary stents for ISR.     

CT冠状动脉造影结合腺苷负荷核素心肌灌注显像诊断冠心病的应用价值

目的 探讨CT冠状动脉造影(CTCA)结合腺苷负荷核素心肌灌注显像(MPS)、解剖学成像结合功能学成像,无创全面诊断冠心病的可行性与准确性.方法 105例怀疑或诊断为冠心病的患者,在有创性冠状动脉造影(CAG)检查前4周内完成CTCA与腺苷负荷MPS检查.以CAG结果为参照,分别评价CTCA、负荷/静息MPS及CTCA结合MPS诊断冠心病的可行性、准确性及特点.结果 CTCA诊断冠状动脉阻塞性病变的敏感性为97.1%,特异性为75.0%,阳性预测值为8 8.2%,阴性预测值为93.1%,准确性为89.5%;负荷/静息MPS诊断冠状动脉阻塞性病变的敏感性为79.7%,特异性为63.9%,阳性预测值为80.9%,阴性预测值为62.2%,准确性为74.3%;CTCA结合MPS诊断阻塞性冠状动脉病变的敏感性为97.2%,特异性为98.5%,阳性预测值为98.5%,阴性预测值为89.7%,准确性为95.2%.结论 CTCA结合腺苷负荷MPS可以明显提高CTCA诊断冠心病的特异性及阳性预测值,且解剖学结合功能学成像可全面提供冠心病的诊断信息.

Abstract：

Objective To assess the accuracy and feasibility of combination of CT coronary angiography (CTCA) and adenosine stress myocardial perfusion scintigraphy (MPS) for diagnosis of coronary artery disease (CAD). Methods CTCA, MPS were performed in 105 patients with suspected or diagnosed CAD within 4 weeks before coronary angiography (CAG) examination. Results The sensibility,specificity, positive predictive value ( PPV ), negative predictive value ( NPV ) and accuracy were 97. 1%,75.0%, 88.2%, 93.1% and 89. 5%, respectively, for CTCA; 79.7%,63.9%,80.9%,62.2% and 74. 3%, respectively, for MPS and 97. 2% ,98. 5% ,98. 5% ,89. 7% and 95.2%, respectively, for CTCA +MPS. Conclusion Combination of CTCA and adenosine stress MPS, which provided both anatomical and functional information of coronary vessels, could significantly increase the specificity and PPV of diagnosing CAD with CTCA.     

Coronary flow velocity reserve measurement in three major coronary arteries using transthoracic Doppler echocardiography

BACKGROUND: Measurement of the coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography (TTDE) has been reported to be useful for the noninvasive assessment of significant coronary artery stenosis or myocardial ischemia. The purpose of this study was to evaluate the value of this method in three major coronary arteries for detecting myocardial ischemia in the clinical setting. METHODS: We studied 89 consecutive patients who were referred to our outpatient clinic because of chest pain. We measured CFVR using TTDE in three major coronary arteries. We defined CFVR<2.0 in at least one vessel as being positive for myocardial ischemia. The accuracy of CFVR measurements for detecting myocardial ischemia was determined in comparison with exercise thallium-201 (Tl-201) single photon emission computed tomography (SPECT) as a reference standard. RESULTS: CFVR in at least one vessel was successfully measured in 87 of 89 patients (98%). The sensitivity and specificity of CFVR<2.0 in at least one coronary vessel, in any of the coronary territories, was 86% and 89%, respectively. In terms of assessing myocardial ischemia in each coronary artery territory, the agreement between CFVR<2.0 and Tl-201 SPECT for the left anterior descending coronary artery, the posterior descending coronary artery, and the left circumflex coronary artery territories was 95%, 81%, and 73%, respectively. CONCLUSION: Noninvasive CFVR measurement by TTDE may be useful for detecting myocardial ischemia, as well as for identifying ischemic territories in the clinical setting.     

Usefulness of an echo-contrast agent for assessment of coronary flow velocity and coronary flow velocity reserve in the left anterior descending coronary artery with transthoracic doppler scan echocardiography

Background This study assessed the feasibility of transthoracic Doppler scan echocardiography (TTDE) combined with echo-contrast agent in measuring coronary flow velocity (CFV) and coronary flow velocity reserve (CFVR) in the left anterior descending artery. Methods In 68 consecutive patients who underwent cardiac angiography, TTDE was recorded before and after induction of a hyperemic condition with intravenous administration of adenosine triphosphate (0.14 mg/kg/min). After CFV values returned to baseline, the same measurements were repeated while an echo-contrast agent was continuously infused. CFVR was assessed as the ratio of hyperemic to basal CFV. The pulsed wave Doppler scan quality was graded from 1 to 3 (TTDE score: 1, no signal detection; 2, poor definition of outline; 3, optimal outline definition). Results Before enhancement, CFVR could not be measured in 20 patients. Prevalence of delayed stenosis (Thrombolysis In Myocardial Infarction [TIMI] II grade flow) in these patients (30%) was significantly greater than in those whose CFVRs could be measured without enhancement (2%; P <.01). TTDE scores both at baseline and after hyperemia were significantly improved with contrast enhancement (before, 2.8 ± 0.6; after, 3.0 ± 0.3; P <.01; before, 2.6 ± 0.7; after, 3.0 ± 0.3; P <.01; respectively). Overall contrast enhancement increased the rate of successful CFVR measurement from 70% to 97% (P <.01). Sensitivity and specificity of significant left anterior descending artery stenosis detection with CFVR of <2.0 were 94.4% and 87.8%, respectively. Conclusion These data suggest that administration of echo-contrast agent improves pulse wave Doppler scan quality and thus the feasibility of measuring CFVR. (Am Heart J 2002;143:668-75.)     

Noninvasive assessment of coronary flow velocity and coronary flow velocity reserve in the left anterior descending coronary artery by Doppler echocardiography: Comparison with invasive technique

Objectives. The purpose of this study was to evaluate whether transthoracic Doppler echocardiography (TTDE) can reliably measure coronary flow velocity (CFV) and coronary flow velocity reserve (CFVR) in the left anterior descending coronary artery (LAD) in the clinical setting.Background. Coronary flow velocity measurement has provided useful clinical and physiologic information. Advancement in TTDE provides noninvasive measurement of CFV and CFVR in the distal LAD.Methods. In 23 patients, CFV in the distal LAD was measured by TTDE (5 or 3.5 MHz) under the guidance of color Doppler flow mapping at the time of Doppler guide wire (DGW) examination. Coronary flow velocity in the distal LAD were measured at baseline and hyperemic conditions (intravenous administration of adenosine 0.14 mg/kg/min) by both TTDE and DGW techniques. Coronary flow velocity reserve was defined as the ratio of peak hyperemic to basal averaged peak velocity in the distal LAD.Results. Clear envelopes of basal and hyperemic CFV in the distal LAD were obtained in 18 (78%) of 23 study patients by TTDE. There were excellent correlations between TTDE and DGW methods for the measurements of CFV (averaged peak velocity: r = 0.97, y = 0.94x + 0.40; averaged diastolic peak velocity: r = 0.97, y = 0.94x + 0.69; systolic peak velocities: r = 0.97, y = 0.91x + 0.87; diastolic peak velocity: r = 0.98, y = 0.95x + 1.10). Coronary flow velocity reserve from TTDE correlated highly with those from DGW examinations (r = 0.94, y = 0.95x + 0.21).Conclusions. Noninvasive measurement of CFV and CFVR in the distal LAD using TTDE accurately reflects invasive measurement of CFV and CFVR by DGW method.     

Usefulness of 64-detector computed tomographic angiography for diagnosing in-stent restenosis in native coronary arteries

The purpose of this study was to evaluate the accuracy of detector computed tomographic angiographic qualitative and quantitative analyses for the detection of in-stent restenosis (ISR) Previous studies have used qualitative analyses exclusively and have excluded "unevaluable" stents. Multidetector computed tomographic angiography (MDCT) was performed before quantitative coronary angiography in 67 patients with 132 stents that were evaluated by 2 techniques: (1) qualitative, on the basis of degree of visual hypodensity, and (2) quantitative, comparing in-stent with prestent Hounsfield units. All stents were evaluated, irrespective of image quality. The incidence of ISR was 12.5%. The sensitivity (94%), specificity (74%), and positive predictive value (39%) of the qualitative evaluation were superior to the quantitative technique (82%, 54%, and 21%, respectively); negative predictive values were similar (99% vs 95%). Accuracies were equal in stents located in proximal and distal vessels. In conclusion, ISR can be evaluated qualitatively by 64-slice MDCT with excellent sensitivity and negative predictive accuracy without exclusion of unevaluable stents and with reasonable specificity but low positive predictive value. Quantitative analysis was less accurate.     

冠状动脉CT成像和平板运动试验对冠心病的诊断价值

目的探讨冠状动脉CT成像(CTCA)和平板运动试验(TET)对冠心病的诊断价值。方法选择怀疑冠心病并于2周内分别行CTCA、TET及冠状动脉造影检查的患者共254例,以冠状动脉造影结果为对照指标,分析CTCA、TET及两者联合时对冠心病的诊断价值。结果 TET、CTCA及CTCA联合TET的敏感性、特异性、阳性预测值、阴性预测值和准确率分别为:60.8%、64.7%、82.5%、37.6%和61.8%;84.9%、80.9%、92.4%、66.3%和83.9%;88.3%、86.0%、94.2%、74.0%和87.7%。CTCA对左主干病变的检出率明显高于冠状动脉造影(P<0.01)。结论 CTCA和CTCA联合TET在诊断冠心病时的准确率比单独TET高,CTCA对左主干病变的检出更有一定优势。因此,临床上可将CTCA作为可疑冠心病患者的筛查方法之一。     

Feasibility of measuring coronary flow velocity and reserve in the left anterior descending coronary artery by transthoracic Doppler echocardiography in a relatively obese American population

BACKGROUND: Transthoracic Doppler echocardiography (TTDE) assessment of coronary flow velocity reserve (CFVR) has been validated in Asian and European centers. This methodology has not gained acceptability in the United States due to the bias that coronary flow velocity (CFV) by TTDE might be difficult in an obese population with relatively poor acoustic windows. METHODS: Baseline CFV in the left anterior descending coronary artery (LAD) by TTDE was obtained in 67 nonselected American patients. A subset of 38/67 received adenosine infusion for measuring CFVR of the LAD. PURPOSE: The aim of this study was twofold: (1) to determine the feasibility of measuring CFV and CFVR in the LAD by TTDE in a relatively obese American population, and (2) to compare CFV and CFVR values in this population with those previously obtained in a group of Japanese patients. RESULTS: The mean body mass index (BMI) of the American population (28 +/- 6 kg/m2, range: 18-46 kg/m2) was significantly higher than that of the Japanese group (23 +/- 4 kg/m2, range: 15-37 kg/m2). Twenty-five American patients were classified as obese (BMI >30 kg/m2). Baseline CFV was obtained in 60/67 patients (feasibility: 90%) with a 10% need for intravenous contrast agent to enhance the delineation of the CFV envelope. The success rate in recording CFVR in American patients (92%) was nearly identical to that of a Japanese group (99%). The time-averaged peak diastolic coronary flow velocity increased from 15.6 +/- 5.5 cm/sec at baseline to 47.1 +/- 17.9 cm/sec during adenosine infusion, and CFVR was calculated to be 3.22 +/- 1.15 (range: 0.94-5.69). Intraobserver and interobserver variability for the CFV recording was 4.7 and 6.2%, respectively. CONCLUSIONS: These results suggest that the noninvasive measurement of CFV and CFVR of the LAD is feasible even in a relatively obese American population. Furthermore, the success rates for recording CFV and CFVR are similar to those measured in a Japanese population. This methodology has the potential to provide useful physiological information on the coronary circulation in American patients.     

Detection and characterization of coronary bifurcation lesions with 64-slice computed tomography coronary angiography.

AIMS: To compare the performance of 64-slice computed tomography coronary angiography (CTCA) and invasive coronary angiography (ICA) in the detection and classification (according to the Medina system) of bifurcation lesions (BLs). METHODS AND RESULTS: We studied 323 consecutive patients undergoing 64-slice CTCA prior to ICA. All coronary segments >or=2 mm in diameter were evaluated for the presence of a significant (>or=50% diameter reduction on quantitative coronary angiography) BL. Evaluation of BL by CTCA included the assessment of significant lumen obstruction in both main and side branch vessels. Forty-one out of 43 patients (46/48 lesions) with significant BL were identified by CTCA. Excluding coronary segments with non-diagnostic image quality (5%), the sensitivity, specificity, and positive and negative predictive values of CTCA for detecting significant BL were 96, 99, and 85 and 99%, respectively. In 39 of these 41 patients, CTCA assessment was concordant with the Medina lesion classification on ICA. CONCLUSION: Sixty-four-slice CTCA allows accurate assessment of complex BL.     

Non-invasive assessment of coronary arterial tone using trans-thoracic Doppler echocardiography.

BACKGROUND: As coronary flow velocity (CFV) is inversely related to the luminal size that exists for the myocardial bed, the elevated arterial tone can be assessed as the higher flow velocity in the epicardial artery. We examined the usefulness of transthoracic Doppler echocardiography (TTDE) for the assessment of coronary arterial tone. METHODS AND RESULTS: A total of 32 patients underwent TTDE and angiography. The luminal diameter (LD) in the left anterior descending artery (LAD) was measured by using quantitative coronary angiography before and after nitroglycerin (NTG) administration. The ratio of post NTG LD to the control (LD(NTG/Pre)) was assessed as a standard parameter of coronary arterial tone. We also measured CFV and CFV reserve (CFVR) at the LAD by TTDE. We evaluated the change of CFV (CFV(NTG/Pre)) and CFVR (CFVR(NTG/Pre)) following NTG administration. The LD increased from 1.98+/-0.46 to 2.51+/-0.34 mm (p<0.001), while the CFV decreased from 23.9+/-10.0 to 16.3+/-5.6 cm/s (p<0.03), and the CFVR increased from 2.39+/-0.65 to 3.56+/-1.12 (p<0.001). There were significant correlations between CFV(NTG/Pre) and LD(NTG/Pre) (p<0.0001, R2 = 0.532), and between the CFVR(NTG/Pre) and LD(NTG/Pre) (p<0.0001, R2 = 0.715). CONCLUSION: TTDE can assess the coronary arterial tone by measuring the responses of CFV and CFVR to NTG administration.     

Role of transthoracic Doppler-determined coronary flow reserve in patients with chest pain.

BACKGROUND: The assessment of patients with chest pain is an important step to make a diagnosis and clinical decision. Coronary flow reserve (CFR) can be used for the screening of significant coronary stenosis. However, the feasibility and limitation of CFR in those patients remains unknown. METHODS AND RESULTS: A total of 100 patients with chest pain were examined. CFR was measured in all 3 major coronary arteries by using transthoracic Doppler echocardiography (TTDE). Coronary angiography was performed 1 to 3 days after TTDE. CFR in all 3 major coronary arteries could be measured in 83 (83%) of 100 patients. The echo-contrast agent was useful in 32 of 49 patients who had unclear color Doppler images. When CFR <2.0 was regarded as the cut-off point, the overall agreement rate between CFR and the results of coronary angiography was 83% (69 of the 83 patients). In addition, CFR could predict the presence of coronary artery disease satisfactorily (sensitivity 85%, specificity 81%, positive predictive value 89%, negative predictive value 93%). CONCLUSIONS: TTDE seems to be a promising tool for screening patients with chest pain. Moreover, an echo-contrast agent seems to be an effective and supportive tool for patients who have poor visualization of coronary flow.     

Usefulness of 64-detector row computed tomography for evaluation of intracoronary stents in symptomatic patients with suspected in-stent restenosis

To determine whether 64-slice multidetector computed tomographic coronary angiography (MDCTA) can accurately assess the coronary artery lumen in symptomatic patients with previous coronary artery stents and potential in-stent restenosis (ISR). The primary aim was to determine the accuracy of binary ISR exclusion using MDCTA compared with invasive catheter angiography (ICA). Secondary aims were comparisons of stent dimensions measured using MDCTA and variables that affect accuracy. Forty patients with previous stent placement underwent both ICA and 64-slice MDCTA after elective presentation with chest pain, and ICA quantitative coronary angiographic data were used as the reference standard. Thirty-six men and 4 women (age 64 +/- 10 years; range 44 to 83) with 103 stents (2.8 +/- 1.6 stents/patient) were comparatively evaluated (stent exclusion rate 9.6%). There were 45 bare-metal and 58 drug-eluting stents (20 +/- 18 months after implantation) with an average diameter of 3.23 +/- 0.7 mm. Overall accuracy for the detection of significant ISR showed sensitivity, specificity, and positive and negative predictive values of 85%, 86%, 61%, and 96% for proximal stents > or =3 mm, which improved to 100%, 94%, 81%, and 100%; if the visible luminal diameter on MDCTA was <1.5 mm, accuracy decreased to 40%, 84%, 29%, and 90%, respectively. In conclusion, 64-slice MDCTA assessment of symptomatic patients with suspected clinically significant ISR is a realistic alternative to ICA if reference stent diameter is > or =2.5 mm and visible lumen cross-sectional diameter is > or =1.5 mm, for which a negative MDCTA result virtually excludes the presence of significant ISR.     

Subtraction coronary CT angiography for calcified lesions

One of the main problems in coronary angiography using 64-row computed tomography (CT) is that the presence of severe calcification interferes with the assessment of lesions, which reduces diagnostic accuracy and may even make assessment of some coronary artery segments impossible. With 320-row CT, it is possible to avoid this problem by performing subtraction coronary CT, which fully exploits the performance capabilities of the CT system. However, subtraction coronary CT has several limitations. When these limitations have been overcome, this technique is expected to become a useful method for assessing patients with severe calcification and evaluating coronary artery stents.     

双能量CT和320排CT冠状动脉减影技术的临床应用

双能量CT与320排CT目前已广泛应用于临床,在心血管相关检查领域也得到较多应用。冠状动脉CT血管成像具有较高的阴性预测值,一定程度上避免了不必要的有创操作,但因为钙化斑块及金属支架产生的硬化伪影,对评估冠状动脉管腔狭窄程度造成了干扰,导致狭窄程度被过分评估或无法评估,故减影技术被应用于冠状动脉成像,通过去除钙化斑块及支架,从而显示出真实管腔,减少了对管腔狭窄程度的误判。现就双能量CT及320排CT减影技术的原理、发展、临床应用以及不足之处进行阐述。     

Usefulness of 64-slice multidetector computed tomography for detecting drug eluting in-stent restenosis

The aim of this study was to evaluate the accuracy of a new-generation spiral multidetector computed tomographic scanner (the Brilliance 64) in the diagnosis of coronary in-stent restenosis (ISR). Forty-one patients with 87 coronary stents (70 drug-eluting stents) implanted were examined. Patients underwent multidetector computed tomography (MDCT) 6.7 +/- 6.9 days before scheduled invasive coronary angiography, using intravenous contrast enhancement. Images were reconstructed in multiple formats using retrospective electrocardiographic gating. Stents were viewed in their long and short axes and were visually classified for the presence or absence of binary ISR (diameter reduction >50%), including the 5-mm borders proximal and distal to the stent. ISR was found by invasive coronary angiography in 13 of the stented segments (15%) and in 8 patients (19%). Of these, 11 cases of ISR were correctly detected by MDCT; additionally, 1 severely calcified stented segment was considered as occluded by MDCT (sensitivity 84%, 95% confidence interval [CI] 54% to 98%). Seventy-three of 74 stented segments without ISR were correctly classified by MDCT (specificity 97%, 95% CI 93% to 100%), whereas 2 stented segments were classified as false-negative ISR. The positive predictive value was 92% (95% CI 84% to 97%), the negative predictive value was 97% (95% CI 90% to 99%), and predictive accuracy was 96% (95% CI 90% to 99%). After the exclusion of the calcified stented segment, the sensitivity, specificity, positive predictive value, negative predictive value, and predictive accuracy were 84% (95% CI 74% to 91%), 100% (95% CI 96% to 100%), 100% (95% CI 96% to 100%), 97% (CI 90% to 99%), and 98% (95% CI 92% to 99%), respectively. In conclusion, even with improved scanner technology, the sensitivity for the detection of ISR was moderate (84%). Thus, further studies are needed to determine whether MDCT will be a clinically useful and cost-effective tool for the evaluation of ISR in the clinical arena.