Multislice computed tomography: angiographic emulation versus standard assessment for detection of coronary stenoses

The present study investigated angiographic emulation of multislice computed tomography (MSCT) (catheter-like visualization) as an alternative approach of analyzing and visualizing findings in comparison with standard assessment. Thirty patients (120 coronary arteries) were randomly selected from 90 prospectively investigated patients with suspected coronary artery disease who underwent MSCT (16-slice scanner, 0.5 mm collimation, 400 ms rotation time) prior to conventional coronary angiography for comparison of both approaches. Sensitivity and specificity of angiographic emulation [81% (26/32) and 93% (82/88)] were not significantly different from those of standard assessment [88% (28/32) and 99% (87/88)], while the per-case analysis time was significantly shorter for angiographic emulation than for standard assessment (3.4 ± 1.5 vs 7.0 ± 2.5 min, P < 0.001). Both interventional and referring cardiologists preferred angiographic emulation over standard curved multiplanar reformations of MSCT coronary angiography for illustration, mainly because of improved overall lucidity and depiction of sidebranches (P < 0.001). In conclusion, angiographic emulation of MSCT reduces analysis time, yields a diagnostic accuracy comparable to that of standard assessment, and is preferred by cardiologists for visualization of results.     

Rest-injected thallium-201 redistribution and resting technetium-99m methoxyisobutylisonitrile uptake in coronary artery disease: relation to the severity of coronary artery stenosis

To compare rest-injected thallium-201 (Tl) redistribution and resting technetium-99m methoxyisobutylisonitrile (^99mTc-MIBI) myocardial uptake in chronic coronary artery disease (CAD), 15 patients with angiographically proven CAD and left ventricular (LV) dysfunction (ejection fraction 34%±9%) were studied. All patients underwent rest-redistribution Tl and resting ^99mTc-MIBI cardiac imaging. Gated ^99mTc-MIBI images were also acquired to assess regional LV wall motion (WM). Myocardial segments (n=225) were divided into three groups on the basis of the degree of coronary artery stenosis: group 1 (total occlusion, n=82), group 2 (50%–99% of stenosis, n=84) and group 3 (<50% of stenosis, n=59). WM was significantly worse in groups 1 and 2 compared to group 3 (P<0.001), but no difference was observed between groups 1 and 2. TI and ^99mTc-MIBI uptake were significantly lower in groups 1 and 2 compared to group 3 (P < 0.001), and in group 1 compared to group 2 (P<0.001). When TI and ^99mTc-MIBI uptake were directly compared, TI uptake was higher than ^99mTc-MIBI uptake in group 1 (P<0.001), while no significant difference was observed in groups 2 and 3. Thus, both rest-injected TI redistribution and resting ^99mTc-MIBI uptake reflected the severity of coronary artery stenosis in CAD. However, in myocardial segments with total coronary occlusion T1 uptake was significantly higher than ^99mTc-MIBI uptake. Our data suggest that rest-injected Tl redistribution cardiac imaging may identify, more accurately than resting ^99mTc-MIBI imaging, the presence of viable myocardium in chronic CAD, particularly when the coronary blood flow is severely impaired.     

Does coronary stenting following balloon angioplasty improve myocardial fractional flow reserve?

Purpose: Suboptimal distal coronary flow reserve after successful balloon angioplasty has been attributed to angiographically unrecognized inadequate lumen expansion, and adjunct coronary stenting has been shown to improve coronary flow reserve. The aim of this study was to investigate whether myocardial fractional flow reserve (FFRmyo) would increase further after coronary stenting compared with balloon angioplasty alone in the same patient group. Methods: FFRmyo and quantitative coronary angiography were obtained before and after pre-stent balloon dilation, and again after stent placement in 11 patients (7 left anterior descending artery, 3 right coronary artery and 1 left circumflex artery). FFRmyo was calculated as the ratio of Pd/Pa during intracoronary adenosine 5′-triphosphate (50 μg and 20 μg in the left and right coronary arteries, respectively)-induced maximum hyperemia, where Pd represents mean distal coronary pressure measured by a 2.1 Fr infusion catheter and Pa represents mean aortic pressure measured by the guiding catheter. Results: Percent diameter stenosis significantly decreased after balloon angioplasty (74% ± 15% vs 37% ± 17%, p < 0.001), and decreased further after stent placement (18% ± 10%, p < 0.001 vs baseline and balloon angioplasty). FFRmyo after coronary stenting (0.85 ± 0.09) was significantly higher than that at baseline (0.51 ± 0.16, p < 0.001) and after balloon angioplasty (0.77 ± 0.11, p < 0.05). There was a significant correlation between angiographic variables and FFRmyo. The increase in lumen dimensions after coronary stenting was followed by a further significant improvement of FFRmyo. Conclusion: These results suggest that coronary stenting may provide a more favorable functional status and lumen geometry of residual coronary stenosis compared with balloon angioplasty alone.     

Myocardial flow reserve is influenced by both coronary artery stenosis severity and coronary risk factors in patients with suspected coronary artery disease

Purpose Myocardial flow reserve (MFR) measurement has an important role in assessing the functional severity of coronary artery stenosis. However, a discrepancy between the anatomical severity of coronary artery stenosis and MFR is often observed. Such a discrepancy may be explained by coronary risk factors. In this study, we aimed to investigate the influence of coronary artery stenosis severity and risk factors on MFR.Methods Seventy-four patients suspected to have coronary artery disease and seven age-matched healthy volunteers were enrolled. Myocardial blood flow (MBF) and MFR were measured using ¹⁵O-labelled water PET. Regional MFR was calculated in regions with significant coronary artery stenosis (stenotic regions) and in regions without significant stenosis (remote regions). The contributions of coronary artery stenosis severity and coronary risk factors were assessed using univariate and multivariate analyses.Results In stenotic regions, MFR correlated inversely with coronary artery stenosis severity (r=−0.50, p<0.01). Univariate analysis did not show any significant difference in MFR between the patients with and the patients without each risk factor. In remote regions, however, MFR was significantly decreased in the diabetes and smoking groups (each p<0.05). By multivariate analysis, diabetes and smoking were independent predictors of MFR (each p<0.05). In the group with more than one risk factor, MFR was significantly lower (2.78±0.79) than in the other group (3.40±1.22, p<0.05).Conclusion MFR is influenced not only by coronary stenosis severity but also by coronary risk factors. In particular, the influence of risk factors should be considered in regions without severe coronary stenosis.This study received no financial sponsorship.     

Non-invasive assessment of coronary artery geometry using coronary CTA

AimTo assess the association of coronary artery geometry with the severity of coronary artery disease (CAD).Methods73 asymptomatic individuals at increased risk of CAD due to peripheral vascular disease (18 women, mean age 63.5 ± 8.2 years) underwent coronary computed tomography angiography (coronary CTA) using first generation dual-source CT. Curvature and tortuosity of the coronary arteries were quantified using semi-automatically generated centerlines. Measurements were performed for individual segments and for the entire artery. Coronary segments were labeled according to the presence of significant stenosis, defined as >70% luminal narrowing, and the presence of plaque. Comparisons were made by segment and by artery, using linear mixed models.ResultsOverall, median curvature and tortuosity were, respectively, 0.094 [0.071; 0.120] and 1.080 [1.040; 1.120] on a per-segment level, and 0.096 [0.078; 0.118] and 1.175 [1.090; 1.420] on a per-artery level. Curvature was associated with significant stenosis at a per-segment (p < 0.001) and per-artery level (p = 0.002). Curvature was 16.7% higher for segments with stenosis, and 13.8% higher for arteries with stenosis. Tortuosity was associated with significant stenosis only at the per-segment level (p = 0.002). Curvature was related to the presence of plaque at the per-segment (p < 0.001) and per-artery level (p < 0.001), tortuosity was only related to plaque at the per-segment level (p < 0.001).ConclusionCoronary artery geometry as derived from coronary CTA is related to the presence of plaque and significant stenosis.     

Quantification of coronary artery stenosis with high-resolution CT in comparison with histopathology in an ex vivo study

Purpose

To investigate the ex vivo performance of high-resolution computed tomography (CT) for quantitative assessment of percentage diameter stenosis in coronary arteries compared to histopathology.

Materials and methods

High-resolution CT was performed in 26 human heart specimens after the injection of iodinated contrast media into the coronary arteries. Coronary artery plaques were visually identified on CT images and the grade of stenosis for each plaque was measured with electronic calipers. All coronary plaques were characterized by histopathology according to the Stary classification, and the percentage of stenosis was measured.

Results

CT depicted 84% (274/326) of all coronary plaques identified by histology. Missed plaques by CT were of Stary type I (n = 31), type II (n = 16), and type III (n = 5). The stenosis degree significantly correlated between CT and histology (r = 0.81, p < 0.001). CT systematically overestimated the stenosis of calcified plaques (mean difference - 11.0 ± 9.5%, p < 0.01) and systematically underestimated the stenosis of non-calcified plaques (mean difference −6.8 ± 10.4%, p < 0.05), while there was no significant difference for mixed-type plaques (mean difference −0.4 ± 11.7%, p = 0.85). There was a significant underestimation of stenosis degree as measured by CT for Stary II plaques (mean difference −14 ± 9%, p < 0.01) and a significant overestimation for Stary VII plaques (mean difference 9 ± 10%, p < 0.05), but there was no significant difference in stenosis degree between both modalities for other plaque types.

Conclusions

High-resolution CT reliably depicts advanced stage coronary plaques with an overall good correlation of stenosis degree compared to histology, however, the degree of stenosis is systematically overestimated in calcified and underestimated in non-calcified plaques.     

Influence of radiographic contrast agents on quantitative coronary angiography

Purpose Quantitative angiographic studies on the vasomotility of epicardial coronary arteries are gaining increasing relevance. We investigated whether radiographic contrast agents might influence coronary vasomotor tone and thereby the results of such studies. Methods Coronary angiograms were taken in 12 patients with coronary artery disease at intervals of 5, 3, 2, and 1 min with the low-osmolar, nonionic contrast agent iopamidol 300, and were repeated at identical intervals with the high-osmolar, ionic agent diatrizoate 76%. Results Quantitative cine film analysis demonstrated no significant diameter changes in angiographically normal and stenotic coronary arteries with iopamidol. With diatrizoate, however, normal segments were dilated 2%±2% (p<0.01) after 2 min and 10%±3% after the 1 min interval (p<0.001). Stenoses showed no uniform responses to diatrizoate. Conclusion Low-osmolar, nonionic contrast agents should be preferred for quantitative angiographic studies on epicardial coronary vasomotility. When using ionic contrast agents, injection intervals of at least 3 min are required.     

Instability of reference diameter in the evaluation of stenosis after coronary angioplasty: Percent diameter stenosis overestimates dilative effects due to reference diameter reduction

Purpose: To examine changes in the reference segment luminal diameter after coronary angioplasty. Methods: Sixty-one patients with stable angina pectoris or old myocardial infarction were examined. Coronary angiograms were recorded before coronary angioplasty (pre-angioplasty) and immediately after (post-angioplasty), as well as 3 months after. Artery diameters were measured on cine-film using quantitative coronary angiographic analysis. Results: The diameters of the proximal segment not involved in the balloon inflation and segments in the other artery did not change significantly after angioplasty, but the reference segment diameter significantly decreased (4.7%). More than 10% luminal reduction was observed in seven patients (11%) and more than 5% reduction was observed in 25 patients (41%). More than 5% underestimation of the stenosis was observed in 22 patients (36%) when the post-angioplasty reference diameter was used as the reference diameter, compared with when the pre-angioplasty measurement was used and more than 10% underestimation was observed in five patients (8%). Conclusion: This study indicated that evaluation by percent diameter stenosis, with the reference diameter from immediately after angioplasty, overestimates the dilative effects of coronary angioplasty, and that it is thus better to evaluate the efficacy of angioplasty using the absolute diameter in addition to percent luminal stenosis.     

Influence of cardiac hemodynamic parameters on coronary artery opacification with 64-slice computed tomography

The purpose of this study was to evaluate the influence of ejection fraction (EF), stroke volume (SV), heart rate, and cardiac output (CO) on coronary artery opacification with 64-slice computed tomography (CT). Sixty patients underwent, retrospectively, electrocardiography-gated 64-slice CT coronary angiography. Left ventricular EF, SV, and CO were calculated with semi-automated software. Attenuation values were measured and contrast-to-noise ratios (CNRs) were calculated in the proximal right coronary artery (RCA) and left main artery (LMA). Mean EF during scanning was 61.5±12.4%, SV was 63.2±15.6 ml, heart rate was 62.5±11.8 beats per minute (bpm), and CO was 3.88±1.06 l/min. There was no significant correlation between the EF and heart rate and the attenuation and CNR in either coronary artery. A significant negative correlation was found in both arteries between SV and attenuation (RCA r=−0.26, P<0.05; LMA r=−0.34, P<0.01) and between SV and CNR (RCA r=−0.26, P<0.05; LMA r=−0.26, P<0.05). Similarly, a significant negative correlation was found between the CO and attenuation (RCA r=−0.42, P<0.05; LMA r=−0.56, P<0.001) and between the CO and CNR (RCA r=−0.39, P<0.05; LMA r=−0.44, P<0.001). The actual hemodynamic status of the patient influences the coronary artery opacification with 64-slice CT, in that vessel opacification decreases as SV and CO increase.     

Preoperative extracranial carotid artery examination with ultrasonography in patients undergoing coronary artery bypass grafting in Japan

Purpose We investigated the incidence, degree, and plaque characteristics of extracranial carotid stenosis with carotid ultrasonography (CUS) in patients undergoing coronary artery bypass grafting (CABG). Materials and methods Preoperative CUS was performed on 221 patients (442 carotid arteries) undergoing CABG. The degree of extracranial carotid stenosis was calculated based on the area stenosis, and it was classified into six grades as follows: grade (G) 0, G1 (1%–29%), G2 (30%–49%), G3 (50%–69%), G4 (70%–99%), and G5 (occlusion). Results The incidence of G4 was 4.1% and G5 1.6%. There were 48 arteries rated G3 or G4. Hypoechoic plaque was detected in 28 of the 48 arteries (58%), and heterogeneous plaque was detected in 37 arteries (73%). Ulcerative plaque was detected in 27 arteries (56%); when comparing the G3 and G4 groups, ulcerative plaque was found more frequently in G4 than in G3 (14/18 vs 13/30 arteries, P < 0.02). Conclusion Our study demonstrated that patients undergoing CABG with extracranial severe carotid stenosis tend to have heterogeneous, hypoechoic, and ulcerative plaque. We believe that preoperative CUS should be used to evaluate the plaque characteristics of extracranial carotid stenosis.     

DSA冠状动脉狭窄与MRI相应供血区心肌缺血、坏死程度的对比分析

目的 探讨MRI所检出的心肌缺血和坏死与供血冠状动脉狭窄程度的关系。资料与方法 47例在1周内完成MRI心脏检查与DSA冠状动脉造影检查,判断心肌有无缺血和心肌坏死的程度,并与DSA结果对照分析两者关系。结果 随着DSA冠状动脉狭窄程度的增加,MRI检出相应供血区心肌有缺血改变的阳性率也逐渐增加,两者非常显著相关（P〈0．0001）。在冠状动脉狭窄程度〉70％的56支血管中,MRI仅有2处（3．6％）未检出缺血改变。随着DSA冠状动脉狭窄程度的增加,MRI检出相应供血区心肌有坏死改变的阳性率也逐渐增加．两者亦非常显著相关（P〈0．001）,在冠状动脉狭窄程度〉80％的39支血管中,MRI检出有不同程度心肌坏死改变的共27处（69、2％）,在冠状动脉狭窄程度〉90％的22支血管中,MRI检出有不同程度心肌坏死改变的共17处（77．3％）,其中透壁心肌坏死改变共11处（50％）。结论 MRI检查可清晰显示心肌缺血、坏死的位置、程度,其结果与DSA冠状动脉情影结果密切相关．两者的一致性较高且有百相支持和补充作用．     

Coronary artery disease: Which degree of coronary artery stenosis is indicative of ischemia?

Purpose

To prospectively determine the best cut-off value of stenosis degree for low-dose computed tomography coronary angiography (CTCA) to predict the hemodynamic significance of coronary artery stenoses compared to catheter angiography (CA) using a cardiac magnetic resonance based approach as standard of reference.

Materials and methods

Fifty-two patients (mean age, 64 ± 10 years) scheduled for CA underwent cardiac magnetic resonance (CMR) at 1.5-T and dual-source CTCA using prospective ECG-triggering the same day. Diagnostic performance of CTCA and CA to detect myocardial ischemia was evaluated with CMR as the standard of reference. The diagnostic performance and best cut-off values to predict the hemodynamic significance of coronary were determined from receiver operating characteristics analysis (ROC).

Results

CA revealed >50% stenoses in 131/832 segments (15.7%) in 78/156 (50.0%) coronary arteries in 32/52 (62%) patients. CTCA revealed >50% stenoses in 148/807 (18.3%) segments, corresponding to 83/156 (53.2%) coronary arteries in 34/52 (65.4%) patients. CMR revealed ischemia in 118/832 (14.2%) myocardial segments corresponding to the territories of 60/156 (38.5%) coronary arteries in 29/52 (56%) patients. ROC analysis showed equal diagnostic performance for low-dose CTCA and CA with areas under the curve (AUC) of 0.82 and 0.83 (P = 0.64). The optimal cut-off value was determined at stenosis of >60% for the prediction of hemodynamically significant coronary stenosis by CTCA. Using this cut-off value, sensitivity, specificity, NPV and PPV to predict hemodynamic significance by CTCA were 100%, 83%, 100%, and 88% on a per-patient basis and 88%, 73%, 83% and 81% on a per-artery analysis, respectively.

Conclusion

By considering coronary stenosis >60%, diagnostic performance for predicting the hemodynamic significance of coronary stenosis by CTCA is optimal and equals that of CA.     

Influence of intra-coronary enhancement on diagnostic accuracy with 64-slice CT coronary angiography

We assessed the effect of intra-coronary attenuation on diagnostic accuracy using 64-slice computed tomography coronary angiography (CT-CA). We enrolled 170 patients with suspected coronary artery disease who underwent conventional coronary angiography (CA) and 64-slice CT-CA (100 ml of Iomeprol 400 mg I/ml at 4 ml/s). The study population was divided into two groups (85 patients each based on median attenuation of 326 HU) based on mean arterial attenuation; group 1 with low attenuation and group 2 with high attenuation. Diagnostic accuracy for the detection of significant coronary artery stenosis was determined for both groups using CA as reference standard. Overall, 163 significant stenoses were detected in 1,030 assessable coronary artery segments in group 1 compared with 160 significant stenoses in 1,020 assessable segments in group 2. The average intra-coronary attenuation was significantly (P < 0.05) higher for group 2 (388 ± 46 HU) compared with group 1 (291 ± 33 HU). The corresponding sensitivity and specificity values for detection of significant coronary artery stenosis were higher for group 2 (96.3% and 97.6%, respectively) than for group 1 (82.8% and 93.2%, respectively) and were more marked in distal coronary segments than in proximal segments. Higher intra-coronary attenuation on CT-CA results in greater diagnostic accuracy for detection of coronary artery stenosis.     

Coronary Events and Anatomy After Arterial Switch Operation for Transposition of the Great Arteries: Detection by 16-Row Multislice Computed Tomography Angiography in Pediatric Patients

The purpose of this study was to evaluate the feasibility of multislice computed tomographic (MSCT) angiography as a noninvasive method for detecting ostial, proximal, and middle segment coronary stenosis or occlusion and anatomy in patients with transposition of the great arteries who had undergone arterial switch operation (ASO). Sixteen-detector-row MSCT angiography was performed in 16 patients treated with ASO for transposition of the great arteries. The median age was 10.3 years (range, 6.2–16.3 years). Sixteen-detector-row MSCT angiography was performed in 16 patients who had undergone ASO. CT imaging was performed in the craniocaudal direction from 2 cm above the carina up to the heart basis. Noninvasive assessment of coronary artery stenosis and anatomy were investigated by MSCT angiography. Two patients were excluded from the study because of artifacts. Of 14 evaluated patients, 1 patient had ostial stenosis (7.1%). A coronary artery anatomy variant was present in six patients: left main artery (LMA) and right coronary artery (RCA) originating from the right sinus as a single orifice (n = 2); left circumflex artery (LCX) originating from the RCA (n = 1); LMA and RCA, after branching to the LCX, originating separately from the right sinus (n = 1); and LMA (n = 1) and left anterior descending artery (LADA; n = 1) originating directly from the right sinus. Intramural bridging in the LAD (n = 2) was detected. Five patients were normal. In conclusion, MSCT angiography, as a noninvasive, feasible technique for assessing coronary stenosis or occlusion and anatomy, can be used in the follow-up of patients who have undergone ASO. This study was accepted as a poster presentation at ESPR 2008.     

Evaluation of temporal windows for coronary artery bypass graft imaging with 64-slice CT

Temporal windows providing the best image quality of different segments and types of coronary artery bypass grafts (CABGs) with 64-slice computed tomography (CT) were evaluated in an experimental set-up. Sixty-four-slice CT with a rotation time of 330 ms was performed in 25 patients (four female; mean age 59.9 years). A total of 84 CABGs (62 individual and 22 sequential grafts) were evaluated, including 28 internal mammary artery (33.3%), one radial artery with sequential grafting (2.4%), and 54 saphenous vein grafts (64.3%). Ten data sets were reconstructed in 10% increments of the RR-interval. Each graft was separated into segments (proximal and distal anastomosis, and body), and CABG types were grouped according to target arteries. Two readers independently assessed image quality of each CABG segment in each temporal window. Diagnostic image quality was found with good inter-observer agreement (kappa=0.62) in 98.5% (202/205) of all graft segments. Image quality was significantly better for saphenous vein grafts versus arterial grafts (P<0.001) and for distal anastomosis to the right coronary compared with other target coronary arteries (P<0.05). Overall, best image quality was found at 60%. Image quality of proximal segments did not significantly vary with the temporal window, whereas for all other segments image quality was significantly better at 60% compared with other temporal windows (P<0.05). Sixty-four-slice CT provides best image quality of various segments and types of CABG at 60% of the RR-interval.     

冠心病患者冠状动脉侧支循环形成的形态学特点分析

目的:分析国人冠状动脉侧支循环的形态学特点。方法:将265例冠心病病人的冠状动脉造影结果进行分析,按Levin的方法进行分类,并与之比较。结果:不同狭窄程度两组间侧支循环开放率差别有高度统计学意义(X2=14.43,P<0.001)。三支血管间侧支循环开放率差别均有统计学意义(X2=3.96,X2=4.28,P<0.05)。东、西方组冠状动脉各支病变的侧支分布的比较差别有高度统计学意义(右冠状动脉X2=9.68,P<0.01;左冠状动脉X2=41.73,P<0.001;左冠状动脉旋支X2=8.54,P<0.01。结论:冠状动脉侧支循环的形成与冠状动脉狭窄程度及病变血管有关。中国人的冠状动脉侧支循环具有独特性。     

MR心肌延遲期強化與CTA冠狀動脈狹窄程度的對照分析

目的:探討MR心肌延遲期強化(Delayed-Enhancement,DE)所檢出的心肌壞死與CTA供血冠狀動脈狹窄程度的相關性。方法:對臨床提示心肌壞死的70例患者成功進行了3T DE-MR檢查,通過觀察患者的心肌壞死程度及心肌運動狀況,對照其同期完成的冠狀動脈CTA結果,分析二者之間的相關性。結果:70例患者共發現心肌壞死54處,83%的心肌壞死發生在狹窄程度≥75%的42支血管中。在冠狀動脈狹窄75%~84%的13支血管中,發生心肌壞死7處(13%);85%~94%的9支血管中,發生心肌壞死12處(22%);≥95%的20支血管,發生心肌壞死26處(48%)。隨著CTA評價冠狀動脈狹窄的嚴重程度增加,DE-MR檢出相應供血區心肌壞死的陽性率也逐漸增加,二者呈顯著性相關(P<0.01)。結論:DE-MR檢測的心肌壞死及其程度與冠狀動脈狹窄的CTA結果互為印證,具有較高的一致性。     

Comparison of quantitative atherosclerotic plaque burden from coronary CT angiography in patients with first acute coronary syndrome and stable coronary artery disease

BackgroundCoronary CTA allows characterization of non-calcified and calcified plaque and identification of high-risk plaque features.ObjectiveWe aimed to quantitatively characterize and compare coronary plaque burden from CTA in patients with a first acute coronary syndrome (ACS) and controls with stable coronary artery disease.Materials and methodsWe retrospectively analyzed consecutive patients with non-ST-segment elevation myocardial infarction (NSTEMI) or unstable angina with a first ACS, who underwent CTA as part of their initial workup before invasive coronary angiography and age- and gender-matched controls with stable chest pain; controls also underwent CTA with subsequent invasive angiography (total n = 28). Culprit arteries were identified in ACS patients. Coronary arteries were analyzed by automated software to quantify calcified plaque (CP), noncalcified plaque (NCP), and low-density NCP (LD-NCP, attenuation <30 Hounsfield units) volumes, and corresponding burden (plaque volume × 100%/vessel volume), stenosis, remodeling index, contrast density difference (maximum percent difference in attenuation/cross-sectional area from proximal cross-section), and plaque length.ResultsACS patients had fewer lesions (median, 1), with higher total NCP and LD-NCP burdens (NCP: 57.4% vs 41.5%; LD-NCP: 12.5% vs 8%; P ≤ .04), higher maximal stenoses (85.6% vs 53.0%; P = .003) and contrast density differences (46.1 vs 16.3%; P < .006). Per-patient CP burden was not different between ACS and controls. NCP and LD-NCP plaque burden was higher in culprit vs nonculprit arteries (NCP: 57.8% vs 9.5%; LD-NCP: 8.4% vs 0.6%; P ≤ .0003); CP was not significantly different. Culprit arteries had increased plaque lengths, remodeling indices, stenoses, and contrast density differences (46.1% vs 10.9%; P ≤ .001).ConclusionNoninvasive quantitative coronary artery analysis identified several differences for ACS, both on per-patient and per-vessel basis, including increased NCP, LD-NCP burden, and contrast density difference.     

Does 16-MDCT angiography scanning direction affect image quality of coronary artery bypass grafts and the native coronary arteries?

To assess the impact of scanning direction on the image quality of coronary artery bypass grafts (CABGs), native coronary arteries (NCAs) were examined by electrocardiographically (ECG) gated 16-row multidetector computed tomography (16-MDCT). Eighty-two patients with 209 grafts were studied by 16-MDCT. Forty-one patients with 111 grafts were scanned craniocaudally. Forty-one patients with 98 grafts were scanned caudocranially. CABG, native coronary arteries were examined in four (proximal, middle, distal, distal anastomoses), three (proximal, middle, distal) segments, respectively. Subjective image quality on a four-point scale was calculated for segments. Scores of groups were compared. Results Image quality scores of proximal, distal segments of the right coronary artery (RCA) were better in caudocranially scanned group (P<0.05). When we subgrouped patients according to initial heart rates (IHR) (group 1, <65 beats/min; group 2, ≥65 beats/min), there was no statistical significance between image quality scores of coronary arteries, CABG when IHR was <65 beats/min in groups regardless of scanning direction. Scores of anastomotic segment of CABG to RCA, middle segments of circumflex coronary artery, proximal and distal segments of RCA in caudocranially scanned group were better when the IHR is ≥65 beats/min compared with the craniocaudally scanned group. When the IHR of the patient is ≥65 beats/min, performing ECG-gated 16-MDCT angiography in the caudocranial direction provides better image quality for evaluation of coronary arteries and CABGs.     

Intracoronary β-brachytherapy using a rhenium-188 filled balloon catheter in restenotic lesions of native coronary arteries and venous bypass grafts

Purpose We have previously demonstrated the efficacy of intracoronary β-brachytherapy using a liquid ¹⁸⁸Re-filled balloon in a randomised trial including de novo lesions. Percutaneous coronary interventions in restenotic lesions and in stenoses of venous bypass grafts are characterised by a high recurrence rate for restenosis and re-interventions. Against this background, we wanted to assess the impact of intracoronary β-brachytherapy using a liquid ¹⁸⁸Re-filled balloon in restenotic lesions in native coronary arteries and venous bypass grafts.Methods In 243 patients, β-brachytherapy with 22.5 Gy was applied at a tissue depth of 0.5 mm. Patients were followed up angiographically after 6 months and clinically for 12 months. The primary clinical endpoint was the incidence of MACE (death, myocardial infarction, target vessel revascularisation). Secondary angiographic endpoints were late loss and binary restenosis rate in the total segment.Results All irradiation procedures were successfully performed. A total of 222 lesions were in native coronary arteries; 21 were bypass lesions. Mean irradiation length was 41.6±17.3 mm (range 20–150 mm) in native coronary arteries and 48.1±33.9 mm (range 30–180 mm) in bypass lesions; the reference diameter was 2.57±0.52 mm and 2.83±0.76 mm, respectively. There was no vessel thrombosis during antiplatelet therapy. Angiographic/clinical follow-up rate was 84%/100%. MACE rate was 17.6% in the native coronary artery group and 38.1% in the CABG group (p<0.03). Binary restenosis rate was 22.5% and 55.6% (p<0.01), and late loss was 0.38±0.72 mm and 1.33±1.11 mm (p<0.001), respectively.Conclusions We conclude that intracoronary β-brachytherapy with a liquid ¹⁸⁸Re-filled balloon using 22.5 Gy at a tissue depth of 0.5 mm in restenotic lesions is safe. It is associated with a low binary restenosis rate, resulting in a low occurrence rate of MACE within 12 months in restenotic lesions in native coronary arteries but not in vein grafts.