Acute myocardial infarction due to left anterior descending coronary artery dissection after blunt chest trauma

Cardiac complications of chest trauma range from arrhythmias to valvular avulsions to myocardial contusion, rupture, and rarely myocardial infarction. We describe a case of a young patient with blunt chest trauma after a motor vehicle accident in whom the diagnosis of myocardial infarction was established a week later because no electrocardiogram or cardiac biomarkers were obtained on presentation. Retrospective review of contrast-enhanced computed tomography (CT) of the chest done on presentation demonstrated a perfusion defect in the distribution of the left anterior descending artery (LAD). Subsequent coronary angiography demonstrated dissection in the proximal LAD. Our case illustrates the importance of electrocardiography and contrast-enhanced chest CT in initial evaluation of patients with blunt chest trauma and suspected injury to the coronary arteries.     

A comparative regional analysis of coronary atherosclerosis and calcium score on multislice CT versus myocardial perfusion on SPECT.

For the noninvasive evaluation of coronary artery disease (CAD), both multislice CT and gated SPECT are available. How these 2 modalities relate, however, is yet unclear. The purpose of this study was to perform a head-to-head comparison of the results of multislice CT and gated SPECT on a regional basis (per vessel distribution territory) in patients with known or suspected CAD. METHODS: One hundred forty patients underwent both multislice CT for coronary calcium scoring and coronary angiography and gated SPECT for myocardial perfusion imaging. The coronary calcium score was determined for each coronary artery. Coronary arteries on multislice CT angiography were classified as having no CAD, insignificant stenosis (<50% luminal narrowing), significant stenosis, or total or subtotal occlusion (>/=90% luminal narrowing). Gated SPECT findings were classified as normal or abnormal (reversible or fixed defects) and were allocated to the territory of one of the various coronary arteries. RESULTS: In coronary arteries with a calcium score of 10 or less, the corresponding myocardial perfusion was normal in 87% (n = 194/224). In coronary arteries with extensive calcifications (score > 400), the percentage of vascular territories with normal myocardial perfusion was lower, 54% (n = 13/24). Similarly, in most of the normal coronary arteries on multislice CT angiography, the corresponding myocardial perfusion was normal on SPECT (156/175, or 89%). In contrast, the percentage of normal SPECT findings was significantly lower in coronary arteries with obstructive lesions (59%) or with total or subtotal occlusions (8%) (P < 0.01). Nonetheless, only 48% of vascular territories with normal perfusion corresponded to normal coronary arteries on multislice CT angiography, whereas insignificant and significant stenoses were present in, respectively, 40% and 12% of corresponding coronary arteries. CONCLUSION: Although a relationship exists between the severity of CAD on multislice CT and myocardial perfusion abnormalities on SPECT, analysis on a regional basis showed only moderate agreement between observed atherosclerosis and abnormal perfusion. Accordingly, multislice CT and gated SPECT provide complementary rather than overlapping information, and further studies should address how these 2 modalities can be integrated to optimize patient management.     

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。     

Quantitative coronary arterial stenosis assessment by multidetector CT and invasive coronary angiography for identifying patients with myocardial perfusion abnormalities

Background

Semi-quantitative stenosis assessment by coronary CT angiography only modestly predicts stress-induced myocardial perfusion abnormalities. The performance of quantitative CT angiography (QCTA) for identifying patients with myocardial perfusion defects remains unclear.

Methods

CorE-64 is a multicenter, international study to assess the accuracy of 64-slice QCTA for detecting ??50% coronary arterial stenoses by quantitative coronary angiography (QCA). Patients referred for cardiac catheterization with suspected or known coronary artery disease were enrolled. Area under the receiver-operating-characteristic curve (AUC) was used to evaluate the diagnostic accuracy of the most severe coronary artery stenosis in a subset of 63 patients assessed by QCTA and QCA for detecting myocardial perfusion abnormalities on exercise or pharmacologic stress SPECT.

Results

Diagnostic accuracy of QCTA for identifying patients with myocardial perfusion abnormalities by SPECT revealed an AUC of 0.71, compared to 0.72 by QCA (P?=?.75). AUC did not improve after excluding studies with fixed myocardial perfusion abnormalities and total coronary arterial occlusions. Optimal stenosis threshold for QCTA was 43% yielding a sensitivity of 0.81 and specificity of 0.50, respectively, compared to 0.75 and 0.69 by QCA at a threshold of 59%. Sensitivity and specificity of QCTA to identify patients with both obstructive lesions and myocardial perfusion defects were 0.94 and 0.77, respectively.

Conclusions

Coronary artery stenosis assessment by QCTA or QCA only modestly predicts the presence and the absence of myocardial perfusion abnormalities by SPECT. Confounding variables affecting the relationship between coronary anatomy and myocardial perfusion likely account for some of the observed discrepancies between coronary angiography and SPECT results.     

64层螺旋CT冠状动脉成像临床应用评价

目的:评价64层螺旋CT冠状动脉成像(64SCTCA)的图像质量和在诊断冠状动脉疾病的临床价值。方法:搜集35例患者64SCTCA的完整资料,并以近期实施的选择性X线冠状动脉成像(SCA)结果为金标准进行对比,对64SCTCA显示的冠状动脉主支及主要分支情况进行分级评估。结果:35例病例可用于评估的冠状动脉共计368支,成功率达95.6%。其中SCA共显示74个节段冠脉有中、重度狭窄(≥50%)。MSCTCA诊断中重度狭窄的敏感性为86.5%,特异性为97.3%,阳性预测值88.9%,阴性预测值96.6%。经配对χ2检验,P>0.05,证明两种检查方法在发现冠状动脉病变方面差异无统计学意义。结论:64层螺旋CT冠状动脉成像是一种无创、快速的成像方法,对诊断冠状动脉≥50%狭窄有较高的敏感性和特异性,适合用于临床怀疑冠心病的患者SCA前的筛选检查。     

Clinical significance of myocardial perfusion abnormalities in patients with varying degree of coronary artery stenosis

OBJECTIVES: (1) To identify myocardial perfusion abnormalities in a cohort of patients having coronary artery disease (CAD) risk factors, with either suspected or clinical evidence of ischaemic heart disease (IHD), and with varying degree of coronary artery stenosis. (2) To evaluate the clinical significance of the extent and severity of perfusion abnormalities assessed by myocardial perfusion scintigraphy (MPS) in relation to the anatomical location of coronary stenosis demonstrated by five-vessel selective coronary angiography (SCA). METHODS: One hundred and thirty-eight patients (106 male, 32 female) with suspected or clinical evidence of IHD underwent diagnostic evaluation at the Central Hospital of Nicosia, between November 2002 and August 2003. The diagnostic work-up included clinical examination, exercise tolerance test, SCA and myocardial perfusion scintigraphy (MPS) using either Tl chloride or Tc-tetrofosmin. RESULTS: Based on the results of SCA, patients were divided into five groups on the basis of stenosis as cross-sectional area of coronary artery lumen and its haemodynamic significance, ranging from group 1=less than 50% coronary stenosis to group 5=100% stenosis (occlusion). Nine of 11 (40.9%) patients with angiographically normal coronary arteries (group 1) had moderate inducible reversible ischaemia on MPS and 9/47 (19.1%) patients with insignificant coronary stenosis (less than 75% stenosis=group 2) had fixed perfusion defects, compatible with previous myocardial infarction. The extent of perfusion abnormalities in post-stress MPS patients from group 2 was not found to be statistically significant (P>0.05) when compared to patients belonging to groups 3, 4 and 5. However, the extent of perfusion abnormalities between patients from group 2, when compared to groups 3, 4 and 5 demonstrated significant statistical difference (P<0.05) on post-rest MPS studies. Furthermore, there was no significant statistical correlation between anatomical location of coronary stenosis and severity of perfusion abnormalities in the corresponding myocardial segments. CONCLUSION: Patients with CAD risk factors, and coronary arteries with insignificant stenosis on angiography, may demonstrate inducible reversible myocardial ischaemia. This is suggestive of coronary endothelial dysfunction. Patients with insignificant coronary artery stenosis and no previous history of adverse coronary events may demonstrate features of previous myocardial infarction on MPS. The severity of perfusion defects demonstrated by MPS may be independent of the anatomical location of coronary artery stenosis.     

Anatomical variants and anomalies of the coronary tree studied with MDCT coronary angiography

Anomalies of the coronary arteries are congenital and in most of the cases asymptomatic, although they may present with severe symptoms such as angina pectoris or cardiac arrest. Multidetector CT coronary angiography (MDCT-CA) permits, through curved multiplanar reconstructions and three-dimensional reformatting, noninvasive visualisation of the coronary tree and its variants and anomalies, providing a more accurate alternative to conventional coronary angiography (CCA). The purpose of this pictorial essay is to describe the main variants and anomalies of the coronary arteries using MDCT imaging with multiplanar and three-dimensional reconstructions.     

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．     

Cardiac CT angiography after coronary artery surgery in children using 64-slice CT scan

Objective

The purpose of this study was to compare the diagnostic accuracy of 64-slice CT with that of invasive angiography in the detection of graft and/or coronary angioplasty stenosis in children who had undergone coronary artery surgery.

Population and methods

Fifteen consecutive children (8 male and 7 female; age 9.2 ± 6.1 years) underwent 64-slice CT because of chest pain or ECG changes mean 4.8 ± 3.7 years after surgical coronary artery surgery; 10 patients had coronary angioplasty using a patch from the saphenous vein, four had mammary artery bypass, and one had saphenous vein bypass. Six main segments of the coronary arteries and all the bypass graft considered as a single segment were analyzed and compared with invasive angiography used as the reference standard.

Results

CT correctly identified the four children with coronary angioplasty and mammary graft lesions that were confirmed by conventional angiography: one patient had a significant stenosis (>50% stenosis) at the mammary bypass graft anastomosis site; three other had non-significant stenosis (<50% stenosis) including a mild lesion of the saphenous vein patch in two patients and a mild lesion at the anastomosis site of the mammary bypass in one. All segments identified as normal by CT in the other 11 children were also found to be normal by conventional angiography.

Conclusion

In centers expert in this technique, 64-slice CT scanning is a promising, rapid, and useful diagnostic technique for evaluating both coronary angioplasty and bypass graft lesions in children who had undergone coronary artery surgery.     

SPECT／CT显像评价“功能相关冠状动脉病变”的价值

目的探讨SPECT／CT显像评价“功能相关冠状动脉（简称冠脉）病变”的可行性及临床价值。方法40例可疑或确诊冠心病患者同机完成^99Tcm-甲氧基异丁基异腈（MIBI）负荷／静息心肌灌注断层显像和冠脉CT造影（CTCA）。负荷／静息心肌灌注显像采用标准二日法,首日行腺苷负荷心肌灌注显像,次日行静息心肌灌注显像及CTCA。腺苷按患者体质量以0．84mg·kg^-1·min^-1经静脉泵匀速给药,CTCA使用标准自动对比剂跟踪扫描程序完成。通过专用融合软件将心肌血流灌注与冠脉三维成像图融合,评价心肌缺血与冠脉病变的相关关系,确定“功能相关冠脉病变”。结果40例患者,CTCA正常20例,异常20例;120支冠脉中共检出33支病变血管,累及左前降支15支,左回旋支9支,右冠脉9支。心肌灌注显像正常22例,心肌缺血和（或）心肌梗死18例。SPECT心肌灌注和CTCA融合图像显示供血区心肌血流灌注正常且无狭窄冠脉占总的无狭窄冠脉的92．47％（86／93）,狭窄〈75％的冠脉中,其供血区心肌缺血或梗死的阳性率占42．86％（6／14,例）,狭窄〉75％或闭塞冠脉中,其供血区心肌缺血的阳性率占92．31％（12／13,例）。120支冠状动脉中20．83％（25／120,支）的病变冠脉为“功能相关冠脉病变”,检测出27例患者中25．93％（7／27,例）有无狭窄病变的冠脉导致心肌缺血;使15．38％（2／13,例）冠脉病变患者免除有创性诊断检查;指导对42．86％（6／14,例）的狭窄〈75％冠脉行药物治疗或冠脉血管重建术治疗;为1支狭窄〉75％的冠脉无需行血管重建术提供依据。结论SPECT／CT心肌灌注和CTCA融合显像可确定“功能相关冠脉病变”,可提供综合信息诊断冠心病和指导治疗。     

Feasibility of combined risk stratification with coronary CT angiography and stress myocardial SPECT in patients with chronic coronary artery disease

Objective

To examine the additional prognostic value of coronary CT angiography (CTA) over myocardial perfusion imaging (MPI) in patients with suspected or known coronary artery disease.

Methods

A series of 157 patients (mean age 69?±?9 years; 76% male; median follow-up 49 months; range 12–82 months) underwent stress MPI with SPECT and coronary CTA within a 6-month interval. Summed stress score (SSS) and summed difference score (SDS) of stress MPI, number of vessels with stenosis, and presence of left main trunk stenosis and high-risk plaques on coronary CTA were examined. Primary endpoints were cardiac death, acute myocardial infarction, or unstable angina requiring revascularization. Secondary endpoints were revascularization?>?60 days after the latter imaging test. All patients were followed up for at least 1 year (mean 45?±?19 months; range 12–82 months).

Results

Nine (6%) patients reached primary endpoints. Cardiac death occurred in 1 (0.6%) patient, myocardial infarction in 5 (3%), and unstable angina requiring hospitalization in 3 (2%). Elective revascularization within 60 days was performed in 31 (20%) patients. Sixteen (10%) patients required revascularization after >?60 days. Primary endpoint event-free survival rates were significantly lower in patients with myocardial ischemia (SDS?≥?2) and high-risk plaques (HRP), and secondary endpoint event-free survival rates in patients with SSS?≥?4 and 3VD. In multivariate analysis, Cox proportional hazards regression analysis revealed HRP (HR?=?8.02; P?=?0.006) and myocardial ischemia (HR?=?11.487; P?=?0.025) were significant predictors of primary endpoints, and 3VD of secondary endpoints (HR?=?4.981; P?=?0.008). Combined ischemia and HRP resulted in the significant increase of the model Chi square in prediction of primary end points from ischemia or HRP alone (17.4 vs. 9.41; P?=?0.005, 17.4 vs. 9.39; P?=?0.005, respectively).

Conclusion

Coronary CT angiography may provide additional prognostic information over MPI.

     

256层CT诊断冠状动脉狭窄与CCA对照分析

目的:评价256层CT诊断冠状动脉狭窄的价值,并与常规冠状动脉造影(CCA)对照分析.方法:80例行256层CT冠状动脉造影(CCTA)及CCA检查者纳入研究.半定量分析CCTA诊断冠状动脉狭窄程度,并以CCA结果为参考标准.评估256层CT诊断冠状动脉狭窄的敏感度、特异度、阳性预测值、阴性预测值和准确性.同时分析25...     

Dynamic intravenous coronary angiography using 2D monochromatic synchrotron radiation.

A method of examination for coronary artery disease that is less invasive and easier than coronary angiography (CAG) has been sought. We have developed a dynamic intravenous coronary angiography (IVCAG) system using synchrotron radiation (SR) and have used it clinically. Four patients suspected of having angina pectoris underwent IVCAG. An SR beam was reflected asymmetrically with a silicon crystal to produce a wide (150 mm x 80 mm) and monochromatic (37 keV) X-ray beam, with an energy level to achieve high sensitivity to the contrast agent. Following an intravenous injection of contrast agent, irradiation was applied for 4 ms periods at 33 ms intervals for dynamic IVCAG at 30 images s-1. Images were acquired with an image intensifier and recorded with a digital fluorography system. The dynamic images permitted clear visualization of the coronary arteries and permitted evaluation of coronary anatomy. Two patients exhibited no stenotic lesions, one patient had a 90% stenosis in the right coronary artery, and the remaining patient had a 25% stenosis at the site of previous percutaneous transluminal coronary angioplasty in the left anterior descending artery (LAD). The total irradiation doses used for IVCAG were less than those for conventional angiography. Dynamic IVCAG can be readily used for the evaluation of coronary arteries.     

Role of 320-slice multislice computed tomography coronary angiography in the assessment of coronary artery stenosis

Objective

To evaluate the effectiveness of the multislice CT coronary angiography, as a non-invasive imaging tool in assessment of coronary artery stenosis.

Patients and methods

The study included 50 patients who were referred for MSCT coronary angiography followed by catheter coronary angiography. Patients with previous coronary bypass grafts and those with coronary stents were excluded. History of contrast allergy, renal impairment and severe chest conditions were exclusion criteria. The coronary angiographic CT studies were performed using a 320 CT scanner. The catheter coronary angiographic studies were performed via femoral arterial puncture. The results of CT angiography were compared with the gold standard catheter angiography.

Results

The positive predictive value and negative predictive value of MSCT coronary angiography in detection of coronary artery stenosis were 94% and 100%, respectively.

Conclusion

In conclusion, MSCT coronary angiography is a very helpful and rapid non-invasive coronary imaging modality that was able to detect and grade coronary artery stenosis better than other noninvasive examinations used to detect CAD, such as exercise stress testing. Due to its very high negative predictive value, it may eliminate the need for invasive coronary procedures in the presence of normal coronary imaging.     

PET/CT冠状动脉血流储备测定在冠状动脉微血管性疾病中的研究进展

冠状动脉微血管性疾病（CMVD）是指在多种致病因素下,冠状动脉微血管结构和（或）功能异常所致的劳力性心绞痛或心肌缺血客观证据的临床综合征。CMVD在冠心病中仍有较高的发病率,部分CMVD预后不佳,对其进行早期诊断、预后评估和治疗干预均具有重要的临床意义。PET/CT定量分析能客观、准确地测量静息和负荷状态下冠状动脉血流灌注量,进而获得冠状动脉血流储备,有效地协助早期诊断CMVD,评估其预后和指导治疗。笔者就PET/CT血流储备测定在CMVD中的研究进展进行综述。     

Cardiac CT angiography (CTA) and nuclear myocardial perfusion imaging (MPI)-a comparison in detecting significant coronary artery disease

RATIONALE AND OBJECTIVES: Endowed with sufficient diagnostic accuracy, electron beam computed tomography angiography (CTA) is being increasingly used to evaluate coronary arteries. However, data on direct comparisons with nuclear myocardial perfusion studies are limited. In this study, we sought to compare the accuracies of CTA and myocardial perfusion imaging (MPI) for identifying symptomatic patients with hemodynamically significant obstructive coronary artery disease (CAD). MATERIALS AND METHODS: In a single-center study, symptomatic outpatients who were scheduled for cardiac catheterization were prospectively enrolled. Only patients with exertional angina or dyspnea were included. After fulfilling the inclusion criteria, 30 patients were enrolled in the study (mean age 54 +/- 9 years and 70% males). Patients underwent MPI, CTA including coronary artery calcification (CAC) measure, and invasive coronary angiography for evaluation of obstructive coronary artery disease. Significant CAD was defined as >50% left main artery stenosis or >70% stenosis of any other epicardial vessel by invasive angiography. The sensitivities, specificities and predictive values of MPI, CAC, and CTA were analyzed per patient RESULTS: CTA demonstrated significant higher sensitivity than MPI (95% vs. 81%, P < .05). CTA demonstrated significantly higher specificity than both MPI (89% versus 78%, P = .04) and CAC (56%, P = .002). CTA also performed better in a per-vessel analysis (sensitivity 94%, specificity 96%) than both nuclear and CAC. There were no significant differences between the sensitivities and specificities of MPI and CAC. CONCLUSION: CTA accurately detects obstructive CAD in symptomatic patients and may be more accurate than MPI or CAC assessment. Larger studies in a more diverse population are needed.     

128层螺旋CT冠状动脉成像筛查冠状动脉病变的临床价值

目的以选择性冠状动脉造影（SCA）为标准,评价128层螺旋cT冠状动脉血管成像（CTA）诊断冠状动脉疾病（CAD）的临床价值。方法回顾我院52例做过冠状动脉CTA与SCA的冠心病患者,进行对照分析。结果128层螺旋cT冠状动脉CTA可获得较好的图像质量,52例患者中,CTA成像检出心肌桥16例,血管内斑块形成98处;17例一侧明显型优势冠状动脉,冠状动脉狭窄86支,包括轻度狭窄22支、中度狭窄24支、重度狭窄40支,SCA诊断心肌桥6例,冠状动脉狭窄84支,包括轻度狭窄22支、中度狭窄21支、重度狭窄41支。结论冠状动脉CTA与SCA相比,不仅能对冠状动脉粥样硬化的狭窄程度作出判断,还可以对粥样斑块的病理性质、斑块的稳定性以及心肌桥提出明确诊断,可以用于CAD的筛查,几乎能代替诊断性的冠状动脉造影。     

CT coronary angiography: Coronary CT-flow quantification supplements morphological stenosis analysis

Background

Our rationale was to evaluate whether a 64-slice CT scanner allows accurate measurement of computed tomographic (CT) changes in coronary artery flow profiles and whether CT flow measurements are suitable for classifying the significance and hemodynamic relevance of a stenosis and thereby supplement as a functional parameter for morphological stenosis analysis.

Methods

A total of 50 patients prospectively underwent computed tomography coronary angiography (coronary CTA) in a multidetector CT scanner (Brilliance 64, Philips) ± 1 day before or after invasive coronary angiography (ICA). Immediately thereafter, 2 radiologists reviewed the imaging data to detect any vessel segments with morphology poorly evaluable by coronary CTA. A locally constant cyclical measurement was acquired in these coronary arteries in breath-hold technique during the passage of a 50 ml bolus of contrast media. For analysis, time–density curves of the bolus passage were registered in the coronary artery and the aorta (internal reference), the up-slopes were determined and correlated with each other. The results were compared with the ICA findings.

Results

47 of 50 CT flow measurements were evaluable. A good correlation was found between the degrees of stenosis and slope ratios in aorta and coronary artery (R² = 0.92). The threshold corridor was 0.55–0.77 for distinguishing hemodynamically (≥70%) from non-hemodynamically relevant stenoses.

Conclusions

CT-based coronary artery flow measurements (CTFM) correlate well with the angiographically determined degree of stenosis and can elevate by non-invasive means the diagnostic accuracy of coronary CTA. From both a clinically diagnostic and scientific standpoint, CTFM proves a suitable method for quantifying coronary blood flow.     

Multidetector row CT coronary angiography: technique and preliminary experience

PURPOSE: To report our preliminary experience with multi-slice spiral CT coronary angiography of the coronary arteries. MATERIALS AND METHODS: 50 volunteers (mean age 61 years, range 45-72) with baseline heart rates below 70 bpm underwent multi-detector row CT coronary angiography (GE Light Speed Plus, 140 kVp, 270 mA, 1.25-mm collimation, 0.5-second rotation time, high quality pitch) with retrospective ECG gating after receiving 140-150 ml of iodinated contrast medium (Iopamiro 300 mg-dl, Bracco, Italy) at a flow rate of 4 ml/sec. Three of the 50 patients had previously undergone coronary procedures (1 anterior descending artery stent, 1 left circumflex artery stent and 1 anterior descending artery percutaneous angioplasty) and three were undergoing follow-up examinations after by-pass surgery. The remaining 44 patients were asymptomatic and had no history of coronary artery disease. All CT angiograms were back-reconstructed from 20 to 80% of the diastolic cycle with 10% increments to establish the phase with fewer "stair-step" motion artefacts for each artery. Patients with heart rates above 70 bpm were administered beta-blockers during the five days preceding the examination in doses appropriate for the patient's clinical characteristics. RESULTS: The CT room occupation time ranged from 25 to 35 minutes (mean time 27') and the post-processing time from 30 to 60 minutes (mean time 40'). The left anterior descending artery was best visualised in middle diastole (70% of cardiac cycle), the circumflex artery at 60% of the cardiac cycle, and the right coronary artery at 40%. Out of 132 arteries, 19 (14.4%) were considered non-assessable due to "stair-step" motion artefacts, whereas 2 (1.5%) were only partially visualised owing to the presence of extensive wall calcifications. Among the 113 assessable arteries, we observed: 72 normal coronary arteries without stenosis or wall calcifications (54.5%); 28 arteries with minimal wall irregularities and stenoses below 50% (21.2%); 7 stenoses >50% involving the right coronary artery (no. 2), the anterior descending arteries (no. 4) and the left circumflex artery (no. 1) (5.3%). In the remaining 6 patients, optimal visualisation of the stents and venous and arterial surgical by-passes was obtained. CONCLUSIONS: Although further larger-scale studies are required to compare MSCT coronary angiography with CT coronary angiography, the application of MSCT technology to the study of the coronary arteries is a promising technique with a good potential for use in routine clinical practice. In selected patients (with baseline heart rates <70 bpm, or after beta-blocker therapy) it is able to provide very interesting results and could be used as a method of choice for following patients after interventional procedures or as a mass-screening tool to select patients to be referred for coronary angiography.     

Assessment of myocardial fibrosis and coronary arteries in hypertrophic cardiomyopathy using combined arterial and delayed enhanced CT: comparison with MR and coronary angiography

Objectives

We sought to determine the feasibility and accuracy of dual-source computed tomography (DSCT) in assessing coronary artery disease and myocardial fibrosis of hypertrophic cardiomyopathy (HCM) compared with cardiac magnetic resonance (CMR) imaging and coronary angiography (CA).

Methods

Forty-seven consecutive patients with HCM were prospectively enrolled. DSCT images were acquired in the arterial and late phases following intravenous contrast medium. The CMR and CA were performed within 7 days. Independent blinded readers read each study. Patients were classified according to myocardial delayed enhanced (MDE) CMR, coronary artery stenosis by CA, and arterial and MDE-DSCT. The diagnostic accuracy of DSCT in detecting coronary stenosis and MDE was analysed.

Results

Wall thickness determined by DSCT was strongly correlated with MR results (r?=?0.91). DSCT and CMR MDE showed substantial agreement for the detection of myocardial fibrosis on per-patient and per-segment levels. The CT classification of patients by arterial stenosis and delayed enhancement had excellent agreement with MR and CA methods.

Conclusions

The comprehensive cardiac CT examination provides reliable coronary artery and myocardial assessments. MDE-DSCT is a robust alternative method to MDE-CMR in assessing myocardial fibrosis in HCM particularly in patients with pacemakers or other contraindications to CMR.

Key Points

? Enhanced cardiac CT provides comprehensive assessment of patients with hypertrophic cardiomyopathy (HCM). ? Myocardial delayed enhanced-CT has comparable accuracy to MDE-MR in detecting HCM fibrosis. ? MDE-CT provides a robust alternative for HCM patients with MR contraindications.