Non-invasive computed tomography coronary angiography as a gatekeeper for invasive coronary angiography

To determine the rate of subsequent invasive coronary angiography (ICA) and revascularization in relation to computed tomography coronary angiography (CTA) results. In addition, independent determinants of subsequent ICA and revascularization were evaluated. CTA studies were performed using a 64-row (n = 413) or 320-row (n = 224) multidetector scanner. The presence and severity of CAD were determined on CTA. Following CTA, patients were followed up for 1 year for the occurrence of ICA and revascularization. A total of 637 patients (296 male, 56 ± 12 years) were enrolled and 578 CTA investigations were available for analysis. In patients with significant CAD on CTA, subsequent ICA rate was 76  %. Among patients with non-significant CAD on CTA, subsequent ICA rate was 20 % and among patients with normal CTA results, subsequent ICA rate was 5.7 % (p < 0.001). Of patients with significant CAD on CTA, revascularization rate was 47 %, as compared to a revascularization rate of 0.6 % in patients with non-significant CAD on CTA and no revascularizations in patients with a normal CTA results (p < 0.001). Significant CAD on CTA and significant three-vessel or left main disease on CTA were identified as the strongest independent predictors of ICA and revascularization. CTA results are strong and independent determinants of subsequent ICA and revascularization. Consequently, CTA has the potential to serve as a gatekeeper for ICA to identify patients who are most likely to benefit from revascularization and exclude patients who can safely avoid ICA.     

Non-invasive assessment of atherosclerotic coronary lesion length using multidetector computed tomography angiography: comparison to quantitative coronary angiography

Multidetector computed tomography angiography (CTA) provides information on plaque extent and stenosis in the coronary wall. More accurate lesion assessment may be feasible with CTA as compared to invasive coronary angiography (ICA). Accordingly, lesion length assessment was compared between ICA and CTA in patients referred for CTA who underwent subsequent percutaneous coronary intervention (PCI). 89 patients clinically referred for CTA were subsequently referred for ICA and PCI. On CTA, lesion length was measured from the proximal to the distal shoulder of the plaque. Quantitative coronary angiography (QCA) was performed to analyze lesion length. Stent length was recorded for each lesion. In total, 119 lesions were retrospectively identified. Mean lesion length on CTA was 21.4 ± 8.4 mm and on QCA 12.6 ± 6.1 mm. Mean stent length deployed was 17.4 ± 5.3 mm. Lesion length on CTA was significantly longer than on QCA (difference 8.8 ± 6.7 mm, P < 0.001). Moreover, lesion length visualized on CTA was also significantly longer than mean stent length (CTA lesion length-stent length was 4.2 ± 8.7 mm, P < 0.001). Lesion length assessed by CTA is longer than that assessed by ICA. Possibly, CTA provides more accurate lesion length assessment than ICA and may facilitate improved guidance of percutaneous treatment of coronary lesions.     

Non-invasive coronary angiography: the clinical value of multi-slice computed tomography in the assessment of patients with prior coronary bypass surgery

Background Contrast enhanced multi-slice computed tomography (MSCT) is the leading modality in non-invasive coronary angiography (CTA) today. We investigated MSCT based assessment of coronary artery bypass grafts (CABG) by analyzing assets and drawbacks of CTA in order to define demands on latest technology. Methods In a clinical setting 39 CABG patients (69.2 ± 1.4 years; male n = 36) underwent CTA (collimation 16 × 0.75 mm, contrast medium 100 ml; 320 mAs, 120 KV). Ninety-seven CABG (61 venous, 36 arterial grafts) were evaluated. A subgroup of 18 patients underwent additional invasive coronary angiography (CA). Results CTA for CABG assessment resulted in an overall sensitivity (sens.) of 100%, specificity (spec.) of 92.4% and positive and negative predictive values (PPV, NPV) of 60% and 100%, respectively. CABG anastomoses showed slightly inferior diagnostic accuracy than other CABG segments. Limitations in imaging quality caused 21% unevaluable segments of the CABG anastomoses. Evaluation of native vessel segments proximal and distal to the anastomoses resulted in a sens, spec, PPV and NPV of 57.5, 94.6, 92 and 67.3%, respectively. With 28.5% unevaluable segments, the native vessel segments showed serious limitations in imaging quality. Radiation exposure was 9.88 ± 3.20 mSv (9.69 ± 3.25 mSv male; 12.08 ± 1.35 mSv female). Conclusion 16-slice MSCT based CABG assessment offers sufficient diagnostic accuracy. However, focussing on the bypass anastomoses and the native revascularized coronary arteries, clinical value is limited.     

Coronary arteries anomalous aortic origin on a computed tomography angiography population: prevalence,characteristics and clinical impact

Anomalous aortic origin of coronary arteries (AAOCA) is one of the most frequent causes of cardiovascular sudden death among the young population. We aimed to determine the prevalence and anatomic characteristics of AAOCA in a population referred to computed tomography angiography (CTA) and to describe the clinical prognosis of these findings at middle term follow-up. From a total of 3539 CTA, 53 were found to have AAOCA. This population was compared to an age and gender matched control group (n = 106) from the same CTA list. A telephone follow-up to determine cardiac events was conducted, with a mean follow-up of 45.9 ± 28.2 months. Prevalence of AAOCA was 1.5 %. The most common AAOCA was an origin of the right coronary artery (RCA) from the left coronary sinus, followed by an origin of the left circumflex artery (LCX) arising from the right coronary sinus. All patients with an anomalous origin of the RCA had an interarterial course. Four additional patients were found to have an interarterial course: 1 with an anomalous origin of LCX and 3 with an anomalous origin of the left main coronary artery (LMCA). At follow-up there were 33 (21.2 %) cardiac events, 9 (17.6 %) on the AAOCA group and 24 (22.9 %) on the control group (p = 0.46). Cardiac events and cardiovascular deaths were not related to any particular AAOCA or to interarterial courses. Among an adult population referred to CTA, AAOCA were not related with worse middle term prognosis when compared to an age- and gender- matched population.     

The evolution and investigation of native coronary arteries in patients after coronary stent implantation: a study by 320-detector CT angiography

To study the role of 320-detector coronary computed tomography angiography (CTA) in assessing native coronary arteries in patients treated with coronary stents. 123 patients with coronary stenting received both CTA and conventional coronary angiography (CCA) within 1 day. The clinical parameters, coronary calcium scoring, CTA and CCA were analyzed to determine the prevalence of significant stenosis of native coronary arteries (SSNCA), the predictive value of CTA and the factors correlating with SSNCA and newly developed SSNCA after stenting (NDSSNCAS), with CCA as the standard of reference, using both vessel-based analysis (VBA) and patient-based analysis (PBA). Both the source and the reconstructed images were analyzed by CTA. All native coronary arteries were interpretable independent of cardiac motion. CTA showed a sensitivity/specificity of 93.5 %/97.3 % and 92.5 %/92.5 % in diagnosing SSNCA in VBA and PBA, respectively. The significant factors related to SSNCA were higher calcium scores (P = 0.003), a higher serum glucose level (P = 0.048), a greater number of vessels without previous stent placement (P = 0.003) and fewer stents implanted within the vessels (P = 0.003). The risk factors showed no significant correlation from PBA on SSNCA or from NDSSNCAS on either VBA or PBA. CTA demonstrates excellent correlation with CCA. The prevalence of SSNCA is significantly correlated with the presence of higher calcium scores in the arteries, a higher serum glucose level, a greater number of vessels without previous stent placement and fewer stents implanted within the vessels; PBA on SSNCA and NDSSNCAS on both VBA and PBA showed no significance.     

Preprocedural coronary CT angiography significantly improves success rates of PCI for chronic total occlusion

Chronic total occlusions of coronary arteries occur in about 20 % of patients with suspected coronary artery disease and are more frequent with increasing age. The success rate of interventions is lower (55–80 %) compared to conventional lesions (>90 %). Coronary CT angiography (coronary CTA) provides information about the occluded segment, which cannot be obtained from invasive angiograms (XA). We therefore hypothesized that preprocedural coronary CTA may improve success rates of percutaneous coronary intervention (PCI) for coronary arteries (CTO). 30 patients with chronic total coronary artery occlusions (mean age 73 years, 26 men) and predicted high complexity were imaged by coronary CTA prior to PCI for CTO. CT data sets were acquired with a 64 detector row dual source scanner and retrograde ECG gating, 0.6 mm collimation and z-flying focal spot, yielding isovoxel spatial resolution of about 0.4 mm. Based on the CT data sets, established complexity criteria for CTO (Euro CTO club, Di Mario et al. in EuroIntervention 3(1):30–43, 2007) were evaluated and compared to invasive coronary angiography. Three-dimensional volume-rendered images of the occluded coronary artery were displayed in the catheterization lab during PCI to guide the advancement of the wire. PCI success, defined as the ability to advance the guide wire into the distal lumen with thrombolysis in myocardial infarction III flow was compared to 43 controls without coronary CTA using propensity score matching based on established criteria of procedural success. The course of the occluded segments was visualized by coronary CTA in all cases. Calcification, lesion length, stump morphology and presence of side branches were underestimated by invasive angiograms when compared to coronary CTA. PCI success rate in 30 patients who underwent pre-procedural CTA was significantly higher than in patients without prior coronary CTA [unmatched: CT 90 % (27/30) vs. no CT 63 % (27/43), p = 0.009; matched: CT 88 % (22/25) vs. no CT 64 % (16/25) p = 0.03]. Through information not readily seen on invasive coronary angiography, coronary CTA can significantly enhance success rates of PCI for CTO.     

The diagnostic accuracy of coronary computed tomography angiography in patients with and without previous coronary interventions

BackgroundInvasive coronary angiography (ICA) is the gold standard for imaging coronary arteries and the severity of coronary artery disease (CAD). Coronary computed tomography angiography (CCTA) has undergone remarkable progress in the diagnosis of CAD.ObjectivesTo evaluate the effect of prior vs no previous coronary interventions on the diagnostic accuracy of CCTA as an alternative to ICA to improve health outcomes for patients with suspected CAD.MethodsA prospective cohort study was carried out among patients suspected of CAD and for evaluation of grafts and stents to investigate recurrent ischemic symptoms. 120 patients imaged by CCTA were then referred to ICA, which is considered the gold standard. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CCTA were assessed relative to ICA.ResultsBased on a per-patient analysis, the comparison with ICA reveals variations in sensitivity, specificity, PPV, NPV and accuracy of CCTA. In patients without any previous coronary interventions, the sensitivity was 97.8%, and specificity was 95.6%. The PPV and NPV were 97.8% and 95.5%, respectively. Regarding patients with coronary artery bypass grafts (CABG), the sensitivity was 95% and specificity 100%. The PPV and NPV were 100% and 90.9%, respectively. Regarding patients with prior percutaneous coronary intervention (PCI), the results were a sensitivity of 84.6%, specificity of 77.8%, PPV of 84.6% and NPV of 77.8%.ConclusionCCTA is a powerful diagnostic tool, especially for the evaluation of the major coronary arteries and evaluation of patients with prior CABG. ICA is recommended for evaluation of patients with an intracoronary stent.     

Diagnostic accuracy of 320-row computed tomography as compared with invasive coronary angiography in unselected, consecutive patients with suspected coronary artery disease

Noninvasive coronary angiography with multislice computed tomography (CT) scanners is feasible with high sensitivity and negative predictive value. The radiation exposure associated with this technique, however, is high and concerns in the widespread use of CT have arisen. We evaluated the diagnostic accuracy of coronary angiography using 320-row CT, which avoids exposure-intensive overscanning and overranging. We prospectively studied 118 unselected consecutive patients with suspected coronary artery disease (CAD) referred for invasive coronary angiography (ICA). All patients had 320-row CT within 1 week of ICA, which, together with quantitative analysis, served as the reference standard. Of the 65 out of 118 patients who were diagnosed as having CAD by ICA, 64 (98 %) were correctly identified at 320-row CT. Noteworthy, 320-row CT correctly detected CAD in 3 patients with atrial fibrillation and ruled out the disease in the other 8 patients. From 151 significant coronary stenoses detected on ICA, 137 (91 %) were correctly identified with 320-row CT. In the per-patient analysis, sensitivity and specificity of 320-row CT were 98 and 91 %, respectively. In the per-vessel analysis, sensitivity and specificity of 320-row CT were 93 and 95 %, respectively. In the per segment analysis, sensitivity and specificity of 320-row CT were 91 and 99 %, respectively. Diameter stenosis determined with the use of CT showed good correlation with ICA (P < 0.001, R = 0.81) without significant underestimation or overestimation (?3.1 ± 24.4 %; P = 0.08). Comparison of CT with ICA revealed a significantly smaller effective radiation dose (3.1 ± 2.3 vs. 6.5 ± 4.2 mSv; P < 0.05) and amount of contrast agent required (99 ± 51 vs. 65 ± 42 ml, P < 0.05) for 320 row CT. The present study in an unselected population including patients with atrial fibrillation demonstrates that 320-row CT may significantly reduce the radiation dose and amount of contrast agent required compared with ICA while maintaining a very high diagnostic accuracy.     

Dual-source coronary CT angiography in patients with high heart rates using a prospectively ECG-triggered axial mode at end-systole

To determine the feasibility of dual-source coronary CT angiography (CTA) using a prospectively electrocardiogram (ECG)-triggered axial mode to target end-systole in patients with high heart rates (HR) as compared with the retrospective mode. One hundred fifty consecutive patients with regular HR > 75 bpm who underwent coronary CTA were enrolled; 75 patients underwent prospectively ECG-triggered coronary CTA targeting only end-systole (Prospective Axial Group) and 75 patients underwent retrospectively ECG-gated coronary CTA (Retrospective Helical Group). The image quality of multiple coronary artery segments was evaluated and radiation doses were recorded. The diagnostic performance of coronary CTA was compared to the reference standard of invasive coronary angiography in 52 patients (35 %) (28 patients in Prospective Axial Group and 24 patients in Retrospective Helical Group). Image quality was not significantly different between the 2 groups (P = 0.784). In subgroup analysis, segment-based sensitivity, specificity, and positive and negative predictive values of coronary CTA were 98, 96, 88 and 99 %, respectively, in the Prospective Axial Group and were 97, 95, 82, and 99 %, respectively, in the Retrospective Helical Group. Mean radiation dose was significantly lower for the Prospective Axial Group than for the Retrospective Helical Group (2.9 ± 1.4 vs. 7.4 ± 3.3 mSv; P < 0.0001). Dual source coronary CTA with a prospective ECG-triggered axial mode targeting end-systole is feasible in patients with regular high HRs for evaluation of coronary artery disease. It provides comparable image quality and diagnostic value with substantially lower radiation exposure as compared to the retrospective ECG–gated helical technique.     

High-pitch coronary CT angiography with third generation dual-source CT: limits of heart rate

To determine the average heart rate (HR) and heart rate variability (HRV) required for diagnostic imaging of the coronary arteries in patients undergoing high-pitch CT-angiography (CTA) with third-generation dual-source CT. Fifty consecutive patients underwent CTA of the thoracic (n = 8) and thoracoabdominal (n = 42) aorta with third-generation dual-source 192-slice CT with prospective electrocardiography (ECG)-gating at a pitch of 3.2. No β-blockers were administered. Motion artifacts of coronary arteries were graded on a 4-point scale. Average HR and HRV were noted. The average HR was 66 ± 11 beats per minute (bpm) (range 45–96 bpm); the HRV was 7.3 ± 4.4 bpm (range 3–20 bpm). Interobserver agreement on grade of image quality for the 642 coronary segments evaluated by both observers was good (κ = 0.71). Diagnostic image quality was found for 608 of the 642 segments (95 %) in 43 of 50 patients (86 %). In 14 % of the patients, image quality was nondiagnostic for at least one segment. HR (p = 0.001) was significantly higher in patients with at least one non-diagnostic segment compared to those without. There was no significant difference (p > 0.05) in HRV between patients with nondiagnostic segments and those with diagnostic images of all segments. All patients with a HR < 70 bpm had diagnostic image quality in all coronary segments. The effective radiation dose and scan time for the heart were 0.4 ± 0.1 mSv and 0.17 ± 0.02 s, respectively. Third-generation dual-source 192-slice CT allows for coronary angiography in the prospectively ECG-gated high-pitch mode with diagnostic image quality at HR up to 70 bpm. HRV is not significantly related to image quality of coronary CTA.     

Dyspnea predicts mortality among patients undergoing coronary computed tomographic angiography

The prognostic implications of dyspnea and typical angina in patients referred for coronary CT angiography have not been examined. We examined features associated with incident mortality risk among individuals undergoing coronary computed tomographic angiography (CCTA) presenting with dyspnea, typical angina, and neither of these symptoms. 1147 consecutive individuals without known CAD (mean 61 years, 61.6 % men) undergoing CCTA comprised the study population 132 with dyspnea, 218 with typical angina, and 797 without dyspnea or typical angina (reference group). Mortality risk in relation to dyspnea or typical angina was evaluated with multivariable Cox proportional hazards models compared to reference. In addition, the prognosis associated with dyspnea or typical angina was assessed among age-matched subgroups. Patients with dyspnea had a greater prevalence of ≥70 % stenosis (p < 0.001) and coronary segments with plaque (p = 0.02) compared to the other two groups. During a follow-up of 3.1 years, 52 individuals died. By multivariable Cox models, compared to patients in reference group, dyspnea patients experienced higher mortality (HR 2.0, 95 % CI 1.0–4.0, p = 0.049) while typical angina patients did not (HR 1.1, 95 % CI 0.6–2.3, p = 0.76). In the matched group, the patients with dyspnea (HR 2.2, 95 % CI 1.1–4.3, p = 0.03) still had significantly reduced survival compared to the other two groups, while those with typical angina did not (HR 1.2, 95 % CI 0.6–2.6, p = 0.62). Dyspnea is associated with increased mortality rate compared to patients with typical angina and those with neither of these symptoms among patients undergoing CCTA.     

Anatomical versus functional assessment of coronary artery disease: direct comparison of computed tomography coronary angiography and magnetic resonance myocardial perfusion imaging in patients with intermediate pre-test probability

Computed tomography coronary angiography (CTA) and cardiac magnetic resonance myocardial perfusion imaging (CMR-MPI) are state-of-the-art tools for noninvasive assessment of coronary artery disease (CAD). We aimed to compare the diagnostic accuracy of CTA and CMR-MPI for the detection of functionally relevant CAD, using invasive coronary angiography (XA) with fractional flow reserve (FFR) as a reference standard, and to evaluate the best protocol integrating these techniques for assessment of patients with suspected CAD. 95 patients (68 % men; 62 ± 8.1 years) with intermediate pre-test probability (PTP) of CAD underwent a sequential protocol of CTA, CMR-MPI and XA. Significant CAD was defined as >90 % coronary stenosis, 40–90 % stenosis with FFR ≤ 0.80 or left main stenosis ≥50 %. Prevalence of significant CAD was 43 %. CTA was more sensitive (100 %) but less specific (59 %) than CMR-MPI (88 and 89 %, respectively) for detection of significant CAD, with a strong trend for higher global diagnostic accuracy of CMR-MPI (88 vs. 77 %, p = 0.05). An integrated approach based on an initial CTA and subsequent referral to CMR-MPI of positive/inconclusive results had the best diagnostic performance (AUC 0.91). The direct referral to XA of patients with positive/inconclusive CTA performed worse than a selective approach based on CMR-MPI results (AUC 0.80 vs. 0.91, p = 0.005). In this intermediate PTP population, CMR-MPI showed a strong trend toward better performance compared to CTA for the assessment of functionally significant CAD. A combined protocol integrating coronary anatomy and function seems to be a very effective approach in the accurate diagnosis of CAD.     

Computer-Aided CT coronary artery stenosis detection: comparison with human reading and quantitative coronary angiography

To evaluate computer-aided stenosis detection for computed tomography coronary angiography (CTA) in comparison with human reading and conventional coronary angiography (CCA) as the reference standard. 50 patients underwent CTA and CCA and out of these 44 were evaluable for computer-aided stenosis detection. The diagnostic performance of the software and of human reading were compared and quantitative coronary angiography (QCA) served as the reference standard for the detection of significant stenosis (>50 %). Overall, three readers with high (reader 1), intermediate (reader 2) and low (reader 3) experience in cardiac CT imaging performed the manual CTA evaluation on a commercially available workstation, whereas the automated software processed the datasets without any human interaction. The prevalence of coronary artery disease was 41 % (18/44) and QCA indicated significant stenosis (>50 %) in 33 coronary vessels. The automated software accurately diagnosed 18 individuals with significant coronary artery disease (CAD), and correctly ruled out CAD in 10 patients. In summary the sensitivity of computer-aided detection was 100 %/94 % (per-patient/per-vessel) and the specificity was 38 %/70 %, the positive predictive value (PPV) was 53 %/42 % and the negative predictive value (NPV) was 100 %/98 %. In comparison, reader 1–3 showed per-patient sensitivities of 100/94/89 %, specificities of 73/69/50 %, PPVs of 72/68/55 % and NPVs of 100/95/87 %. Computer-aided detection yields a high NPV that is comparable to more experienced human readers. However, PPV is rather low and in the range of an unexperienced reader.     

Incidence of persistent renal dysfunction after contrast enhanced coronary CT angiography in patients with suspected coronary artery disease

Contrast-induced nephropathy (CIN) is a potentially serious complication of contrast agents used in computed tomography angiography (CTA). The aim of this study was to evaluate whether persistent renal dysfunction occurs in patients undergoing coronary CTA for suspected stable coronary artery disease (CAD). From a cohort of 957 patients undergone coronary CTA, we identified 402 patients with plasma creatinine levels collected before and within 6 months after CTA. According to the definition of CIN, patients with a ≥25?% increase in plasma creatinine after CTA were evaluated. The post-CTA measurements in 402 patients (195 men, age 62.9?±?9.3 years) were performed at a median of 99 days after CTA. On average, there was no change in plasma creatinine level between the pre- and post-CTA measurements (75.8?±?16.0 and 75.7?±?16.4 µmol/L, respectively; P?=?0.63) but both increases and decreases were commonly detected. Fourteen (3.5?%) patients had a ≥25?% increase in plasma creatinine levels after CTA. A more detailed evaluation of these patients revealed that in 4 patients the increase was explained by other morbidities, whereas in 9 patients the creatinine level returned to the previous levels at later follow-up (median time to normalization: 311 days). Only in 1 (0.2?%) remaining patient, there was a persistent increase in plasma creatinine level, possibly related to the iodine contrast agent exposure. Alterations in plasma creatinine concentration occur frequently. Persistent renal dysfunction attributable to iodine contrast agent exposure is rare in patients referred to coronary CTA for suspected CAD.     

Evaluation neointimal coverage in patients with coronary artery aneurysm formation after drug-eluting stent implantation by optical coherence tomography

The neointimal coverage in patients with coronary artery aneurysms (CAA) formation after drug eluting stent (DES) implantation is not clear. Total of 175 patients who had been implanted DES were identified. Patients were divided into the CAA group (n = 31) and non-CAA group (n = 144) based on the results of the coronary angiography. The cardiac events including angina and acute myocardial infarction were noted, in addition, the neointimal thickness and the frequence of strut malapposition and strut uncoverage were noted. A greater proportion of incomplete neointimal coverage (17.17 vs. 1.9 %, P < 0.001) and malapposition struts (18.2 vs. 1.38%, P < 0.001) were observed in the CAA group. 8 patients in CAA group underwent OCT examination twice in the period of follow-up. The proportion of incomplete neointimal coverage increased significantly as compared the second OCT results with the first examination (18.45 vs. 2.66 %, P < 0.001). Hyperplasia neointimal desquamated from struts and acquired struts incomplete neointimal coverage were detected. Patients with CAA had a higher frequency of cardiac events including angina pectoris (25.81 vs. 6.25 %, P = 0.001) and acute myocardial infarction (9.68 vs. 0.13 %, P = 0.002) and thrombosis (16.13 vs. 0.69 %, P < 0.001). The longitudinal length of CAA in cardiac event group was significantly longer than no cardiac event group (20.0 ± 9.07 vs. 12.05 ± 5.38 mm, P = 0.005). CAA formation after DES implantation frequently associated with cardiac events as a result of stent malapposition and incomplete neointimal coverage. Acquired incomplete neointimal coverage associated with CAA formation.     

Subtraction coronary CT angiography using second-generation 320-detector row CT

The purpose of this study was to explore the feasibility of subtraction coronary computed tomography angiography (CCTA) by second-generation 320-detector row CT in patients with severe coronary artery calcification using invasive coronary angiography (ICA) as the gold standard. This study was approved by the institutional board, and all subjects provided written consent. Twenty patients with calcium scores of >400 underwent conventional CCTA and subtraction CCTA followed by ICA. A total of 82 segments were evaluated for image quality using a 4-point scale and the presence of significant (>50 %) luminal stenosis by two independent readers. The average image quality was 2.3 ± 0.8 with conventional CCTA and 3.2 ± 0.6 with subtraction CCTA (P < 0.001). The percentage of segments with non-diagnostic image quality was 43.9 % on conventional CCTA versus 8.5 % on subtraction CCTA (P = 0.004). The segment-based diagnostic accuracy for detecting significant stenosis according to ICA revealed an area under the receiver operating characteristics curve of 0.824 (95 % confidence interval [CI], 0.750–0.899) for conventional CCTA and 0.936 (95 % CI 0.889–0.936) for subtraction CCTA (P = 0.001). The sensitivity, specificity, positive predictive value, and negative predictive value for conventional CCTA were 88.2, 62.5, 62.5, and 88.2 %, respectively, and for subtraction CCTA they were 94.1, 85.4, 82.1, and 95.3 %, respectively. As compared to conventional, subtraction CCTA using a second-generation 320-detector row CT showed improvement in diagnostic accuracy at segment base analysis in patients with severe calcifications.     

多层螺旋CT血管成像评价冠状动脉血管旁路移植术

目的评价多层螺旋CT(MSCT)冠状动脉成像对冠状动脉桥血管的临床价值。方法28例患者的69条冠状动脉桥血管接受16层和64层螺旋CT冠状动脉成像。对桥血管成像进行影像质量评估,使用多元线性回归方法评估患者心率、心率波动幅度、呼吸运动以及不同CT扫描机对冠状动脉成像质量的影响。其中10位患者26条桥血管的CT血管成像结果与冠状动脉血管造影结果进行对比。结果呼吸运动伪影与冠状动脉桥血管成像质量呈负相关,相关系数为-0.838。64层CT扫描机的影像质量高于16层CT扫描机的影像质量。以CAG结果为参考标准,MSCT冠脉成像诊断桥血管及吻合口狭窄的特异性和敏感性分别为95.7%和92.3%。结论MSCT可以提供可靠的冠状动脉桥血管影像以及较高的诊断准确性。     

Demonstration of the Glagov phenomenon in vivo by CT coronary angiography in subjects with elevated Framingham risk

Computed tomography coronary angiography (CTA) is a novel, non-invasive method for coronary plaque detection and quantification. We hypothesized that CTA can detect early vessel wall thickening with preserved luminal size in patients without known coronary artery disease and intermediate/high Framingham Risk Score (FRS) compared to those with low FRS. Vessel-wall and plaque geometrical and compositional parameters were measured on CTA in 375 coronary segments with a highly standardized method. These parameters were then compared in patients with low versus intermediate/high FRS. The relationship between coronary artery calcium by non-contrast CT scanning (Agatston score) and percent atheroma volume (PAV) was determined by linear regression. P value <0.05 was considered significant. PAV and remodeling index were significantly higher in patients with intermediate/high FRS compared to those with low FRS (45.9 ± 6.8 vs. 42.3 ± 6.7; P = 0.004) and (0.97 ± 0.15 vs. 0.92 ± 0.13; P = 0.04), while minimal luminal diameter and minimal luminal area were similar. There was significant correlation between Agatston score and PAV (r ² = 0.42, P = 0.0036). However, Agatston score and plaque compositional parameters were similar between the groups. In conclusion, we demonstrated that CTA can detect early vessel-wall thickening with preserved luminal size in patients with intermediate/high versus low FRS.     

Assessment of the presence and extent of coronary collateralization by coronary computed tomographic angiography in patients with total occlusions

Coronary computed tomography angiography (CTA) may be helpful to manage patients with chronic coronary occlusions. The aim of this study was to determine the sensitivity and specificity of CTA to detect the presence and extent of coronary collaterals as compared to invasive coronary angiography (ICA). We retrospectively evaluated 26 patients who underwent both coronary CTA and ICA within 3 weeks and demonstrated a total coronary occlusion (TIMI grade 0) in one of the major coronary arteries. CTA was performed using a 64-slice multidetector CT. The presence, and extent of collateralization was assessed by two blinded observers using the Rentrop classification for ICA. CTA accurately identified the presence and location of all 26 total occlusions. The presence of any collaterals was accurately detected in 21/23 patients [sensitivity 91% (CI: 71–98%)] and the absence in three patients [specificity 100% (CI: 29%–100%)]. The sensitivity of coronary CTA to identify patients with collateralization increased from 91 to 94% (CI: 71–99%) and 100% (CI: 59–100%) for collaterals Rentrop grade 2 and 3 in ICA, respectively. Coronary CTA accurately detects the presence of any coronary collateralization in patients with total occlusions. Although CT technology is currently limited in the assessment of individual collaterals and smaller vessels, it may be helpful in the management of patients with total occlusions.     

Comparison of dual-source ct coronary angiography and conventional coronary angiography for detecting coronary artery disease

To evaluate the diagnostic accuracy of dual-source CT coronary angiography for detecting coronary artery stenosis. From February 2008 to January 2009, dual-source CT coronary CT angiography (DSCT-CCTA) and conventional coronary angiography (CAG) were both performed in 84 patients who had either clinical symptoms or a high risk of coronary artery disease. The diagnostic accuracy of DSCT-CCTA was evaluated by comparing it with that of CAG, which was regarded as the gold standard for making the diagnosis of coronary artery disease. Occlusion or stenosis of various degrees was revealed by DSCT-CCTA in 244 segments of 84 patients. Compared to CAG, segment-based sensitivity, specificity, positive predictive value and negative predictive value of DSCT-CCTA were 97.4, 97.8, 92.2 and 100%, respectively. The diagnostic accuracy of DSCT-CCTA for the detection of coronary artery stenosis was 96.5%. The paired χ2 tests revealed no significant difference between DSCT-CCTA and CAG for making the diagnosis of coronary artery disease (P = 0.076). The diagnostic performance of DSCT-CCTA is generally as accurate as that of CAG. Thus, DSCT-CCTA is a reliable non-invasive method for detecting coronary artery stenosis.