Cardiac PET-CT

Integrated positron emission tomography computed tomography (PET/CT) scanners allow a true integration of the structure and function of the heart. Myocardial perfusion PET provides a high sensitivity (91%) and specificity (89%) for the diagnosis of obstructive coronary artery disease (CAD). But, as with single photon emission CT, relative perfusion PET often uncovers only the territory subtended by the most severe coronary stenosis, leading to underestimation of the extent of CAD. In contrast, quantitative PET provides a noninvasive assessment of myocardial blood flow and coronary flow reserve and improves detection of preclinical and multivessel coronary atherosclerosis. Similarly, CT coronary angiography is an accurate means to image the entire continuum of anatomic coronary atherosclerosis from nonobstructive to obstructive CAD. However, not all coronary stenoses are hemodynamically significant and <50% of the patients with obstructive CAD on CT angiography demonstrate stress induced perfusion defects. Stress PET data complement the anatomic information on the CT angiogram by providing instant readings about the ischemic burden of coronary stenoses. Thus, combined PET/CT may be potentially superior to CT angiography alone for the guiding revascularization decisions. Further, fusion of the PET and CT angiogram images allows identification of the culprit stenosis in patients presenting with chest pain. Finally, the advances in molecular imaging and image fusion may soon make noninvasive detection of vulnerable coronary plaques a clinical reality. In summary, integrated PET/CT is a powerful new noninvasive modality that offers the potential for refined diagnosis and management of the entire spectrum of coronary atherosclerosis.     

Diagnostic value of CT angiography in coronary arteries stenosis detection

BACKGROUND: Noninvasive imaging of coronary arteries is very important. CT angiography (multislice computed tomography and electron beam computed tomography -- MSCT and EBT) is most reliable method for noninvasive coronary visualization. PURPOSE: The aim of our study was to evaluate the diagnostic value of CT angiography in coronary arteries stenoses detection in patients with coronary arteries disease (CAD). MATERIALS AND METHODS: 140 patients with CAD who underwent EBT (n=97) or 4-slice CT (n=43) coronary angiography and conventional coronary angiography as a gold standard were included in the study. RESULTS: Sensitivity and specificity of CT angiography in coronary stenoses detection (proximal and mid segments) were 86% and 97%, respectively. Positive and negative predictive values were 90% and 96%, respectively. Overall accuracy was 95%. 6.2% of coronary segments were excluded from the study because of unsatisfactory image quality. CONCLUSIONS: CT angiography is noninvasive method for coronary stenoses detection with high sensitivity and specificity. Nevertheless EBT and 4-slice CT angiography can not replace conventional coronary angiography because of lower temporal and spatial resolution, artifacts in patients with arrhythmias and huge coronary calcification.     

Coronary computed tomography angiography in coronary artery disease

AIM: To investigate the research directions of coronary computed tomography (CT) angiography in the diagnosis of coronary artery disease (CAD) based on a systematic review of the literature.METHODS: A search of articles on coronary CT angiography in the diagnosis of CAD was performed during a 6-year-period between 2005 and 2010 from f ive main radiology journals namely, Radiology, American Journal of Roentgenology, European Radiology, European Journal of Radiology and British Journal of Radiology. Analysis of the references was focused on the research directions of coronary CT angiography with regard to the type of studies in terms of diagnostic value, application of dose-reduction strategies and resultant effective radiation doses with use of these techniques.RESULTS: One hundred and forty two studies were identified which met the selection criteria and were included in the analysis. 64-slice CT (single source anddual-source CT) dominated 78% of the coronary CT angiography studies. Prior to 2007, research was focused on the diagnostic value of coronary CT angiography, but since 2008 more attention has been paid to radiation dose reduction. Radiation dose was reported in 64 studies, representing 45% of total studies published in the f ive radiology journals. Various dose-saving strategies have been implemented and prospective electrocardiography-triggering and high pitch techniques were found to be the most effective approaches for radiation dose reduction, with the corresponding mean effective dose being 3.5 ± 1.9 mSv and 1.7 ± 0.6 mSv, respectively.CONCLUSION: This review shows that the current research in coronary CT angiography has shifted from the previous focus on diagnostic accuracy in CAD to more emphasis on radiation dose reduction.     

Non-invasive coronary computed tomographic angiography for patients with suspected coronary artery disease: the Coronary Angiography by Computed Tomography with the Use of a Submillimeter resolution (CACTUS) trial.

BACKGROUND: Non-invasive coronary angiography by multislice spiral computed tomography (MSCT) is a promising method for the diagnosis of coronary artery disease (CAD). However, the clinical role of this method has not been established for specific patient cohorts. Therefore, the objective of the current prospective, blinded study was to investigate the diagnostic value of coronary MSCT angiography in patients with an intermediate pre-test probability for having CAD when compared with invasive angiography. METHODS AND RESULTS: A total of 243 patients with an intermediate pre-test probability for having CAD were asked to undergo coronary 16- or 64-slice CT angiography before planned invasive angiography from 12 September 2003 to 13 July 2005. The primary end point was defined as the diagnostic accuracy in the detection of significant coronary stenosis (> or =50% lumen diameter reduction) on a per-patient and an 'intention-to-diagnose'-based analysis. Secondary end points comprised per-artery and per segment-based analyses as well as the comparison of diagnostic accuracy of 16- vs. 64-slice MSCT angiography. Of 243 enrolled patients, 129 and 114 patients were studied by 16- and 64-slice CT angiography, respectively. The overall sensitivity, negative predictive value, and specificity for CAD detection by MSCT were 99% (95% CI, 94-99%), 99% (95% CI, 94-99%), and 75% (95% CI, 67-82%), respectively. On a per-segment basis, the use of 64-slice CT was associated with significantly less inconclusive segments (7.4 vs. 11.3%, P < 0.01), resulting in a trend to an improved specificity (92 vs. 88%, P = 0.09). CONCLUSION: In patients with an intermediate pre-test probability for having CAD this large, prospective trial demonstrates that non-invasive coronary CT angiography is a very sensitive method for CAD detection. Furthermore, this method allows ruling out CAD very reliably and safely. Finally, 64-slice CT appears to be superior for CAD detection when compared with 16-slice CT.     

Invasive versus noninvasive (MSCT) coronary angiography. Importance of cardiac diagnostics with multislice computed tomography

Cardiac imaging with fast computed tomography (CT) is a quickly evolving field starting to become established in the cardiac routine work-up. The exclusion of coronary calcification is the most accurate noninvasive method to exclude significant coronary stenosis whereas the detection of calcification identifies coronary arteriosclerosis. The total calcium load correlates with the risk of coronary stenosis, but there is not a 1 : 1 relationship. CT angiography with contrast enhancement offers promises to increase diagnostic accuracy. 4-slice scanners acquire data with a slide width down to 1 mm. The spatial resolution of invasive coronary angiography cannot be achieved yet. Severe coronary stenosis may be excluded with 90% specificity if image quality is not impaired by artifacts, severe calcification, arrhythmia, and a heart rate > 70 beats/min. With present technology, about 26% of segments may not be adequately assessed. Despite these limitations CT angiography is a useful tool to reduce the number of invasive diagnostic angiography.In patients with known coronary artery disease (CAD), progression as well as stent occlusion can be assessed. Instent stenosis can only be diagnosed indirectly. The patency of arterial and venous grafts can be assessed very well including also the bypass insertion site. Actual studies on the significance of noncalcified plaques are in progress.A CT angiography should take place in order to avoid further exposure to radiation. Therefore, patients with typical angina or significant signs of coronary ischemia have to be investigated by invasive methods and do not profit from a CT scan. Preparation and implementation of this method should only be applied in cooperation with radiologists and cardiologists in an experienced center.     

64排螺旋CT冠脉成像与冠脉造影对冠心病诊断的比较

目的：探讨64排螺旋CT冠脉成像对冠心病的诊断价值。方法：以冠脉造影（CAG）结果为金指标，采用64排螺旋CT对100例疑诊冠心病患者的冠脉主干及主要分支400节段进行重建和分析，评价其诊断冠心病的灵敏性和特异性。结果：64排螺旋CT能清晰显示冠脉主干及分支狭窄、钙化、开口起源异常及桥血管病变，对冠脉狭窄性病变的诊断准确性高，诊断冠脉病变的灵敏度96.37％，特异度96．14％，阳性预测值95．88％，阴性预测值96．6％。但对慢性闭塞性病变诊断性的准确率稍差，灵敏度50％，特异度96．77％，阳性预测值62．5％，阴性预测值94．73％。结论：64排螺旋CT冠脉成像对冠脉狭窄病变、桥血管、心肌桥、支架管腔均显影良好，对钙化病变诊断率优于冠脉造影，可以作为冠心病高危人群无创性筛选检查及冠脉支架、搭桥术后随访手段。     

多层螺旋CT冠脉成像技术及其临床应用进展

多层螺旋CT结合回顾性心电门控技术,可采取多相位窗的冠状动脉图像,从中筛选最佳图像并利用后期图像重建技术可模拟出冠状动脉的三维结构。此技术对冠状动脉病变的筛查与诊断、冠状动脉支架置入术及搭桥术后的评价等方面有独特的优势。因其微创、安全、分辨率高等优点,多层螺旋CT冠脉成像的临床应用前景越来越广阔。     

Non-invasive detection of coronary artery disease in patients with left bundle branch block using 64-slice computed tomography.

OBJECTIVES: The goal of this study was to evaluate the diagnostic accuracy of 64-slice computed tomography (CT) to identify coronary artery disease (CAD) in patients with complete left bundle branch block (LBBB). BACKGROUND: Left bundle branch block increases risk of cardiac mortality, and prognosis is primarily determined by the underlying coronary disease. Non-invasive stress tests have limited performance, and conventional coronary angiography (CCA) is usually required. METHODS: Sixty-six consecutive patients with complete LBBB and sinus rhythm admitted for CCA were enrolled. Computed tomography was performed 3 +/- 3.9 days before CCA. The accuracy of 64-slice CT to detect significant stenosis (>50% lumen narrowing) was compared with quantitative coronary angiography. All segments were analyzed regardless of image quality from coronary calcification or motion artifacts. Results were analyzed by patient and by coronary segment (990) using the American Heart Association 15-segment model. RESULTS: Lower heart rates were associated with improved image quality. Computed tomography correctly identified 35 of 37 (95%) patients without significant stenosis and 28 of 29 (97%) patients with significant stenosis on CCA. Computed tomography correctly assessed 68 of 94 (72%) significant stenosis. Overall, accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 64-slice CT for identifying CAD by patient was 95%, 97%, 95%, 93%, and 97%, respectively, and by segment was 97%, 72%, 99%, 91%, and 97%, respectively. CONCLUSIONS: In a routine clinical practice, 64-slice CT detects with excellent accuracy a significant CAD in patients with complete LBBB. A normal CT in this clinical setting is a robust tool to act as a filter and avoid invasive diagnostic procedures.     

Usefulness of multislice computed tomography for detecting obstructive coronary artery disease

The latest generation of multislice spiral computed tomography (MSCT) scanners is capable of noninvasive coronary angiography. We evaluated its diagnostic accuracy to detect stenotic coronary artery disease (CAD). In 53 patients with suspected CAD, contrast-enhanced MSCT and conventional angiography were performed. The CT data were acquired within a single breathhold, and isocardiophasic slices were reconstructed by means of retrospective electrocardiographic gating. Coronary segments of > or = 2 mm in diameter, measured by quantitative angiography, were evaluated. In 70% of the 358 available segments, image quality was regarded as adequate for assessment. The overall sensitivity, specificity, and positive and negative predictive values to detect > or = 50% stenotic lesions in the assessable segments were 82% (42 of 51 lesions), 93% (285 of 307 nonstenotic segments), and 66% and 97%, respectively, regarding conventional quantitative angiography as the gold standard. Proximal segments were assessable in 92%, and distal segments and side branches in 71% and 50%, respectively. Including the undetected lesions in non-assessable segments, overall sensitivity decreased to 61% but remained 82% for lesions in proximal coronary segments. MSCT correctly predicted absent, single, or multiple lesions in 55% of patients. Thus, despite potentially high image quality, current MSCT protocols offer only reasonable diagnostic accuracy in an unselected patient group with a high prevalence of CAD.     

40层螺旋CT冠状动脉成像在冠心病诊断和随访中的价值

目的:分析897例临床确诊或疑似冠心病患者的40层螺旋CT冠状动脉成像结果,以探讨40层螺旋CT冠状动脉成像在冠心病诊断和随访中的价值.方法:262例临床确诊和579例疑似冠心病患者予以40层螺旋CT冠状动脉成像检查,经最大密度投影、容积重建和曲面多平面重建等后处理,其中207 例患者曾行选择性冠状动脉造影检查,将40层螺旋CT冠脉成像检查结果对照冠状动脉造影检查结果计算其敏感性、特异性、准确性、阳性预测值和阴性预测值.有135例患者1年后再次做40层螺旋CT冠状动脉成像检查.结果:94%患者冠状动脉成像图像可用于分析.有斑块伴中重度狭窄病例512例,包括单支病变 216例,2支病变169例,3支病变127例.男女性可疑冠心病患者40层螺旋CT 冠状动脉成像结果显示:无斑块或有斑块伴轻度狭窄的比例女性患者为56.98%(200/351),男性患者为45.18%(103/228),χ~2 =7.72,P<0.01,随着年龄的增长,冠状动脉多支病变逐渐增多.207例多层螺旋CT 冠状动脉成像与冠状动脉造影结果对比显示,冠状动脉分支血管有意义狭窄( ≥50%)的敏感性为84.5%(223/264);特异性为97.3%(1117/1148);阳性预测值为87.8%(223/254);阴性预测值为96.5%(1117/1158);准确性为94.9%(1340/1412).135例患者1年后重复40层螺旋CT冠状动脉成像显示有斑块消失6处、有斑块缩小5处、有新斑块出现9处、有斑块扩大10处.结论:40 层螺旋C T 作为无创性冠状动脉病变诊断技术可作为冠心病筛查,随访的良好方法,尤其适合临床症状较多的女性患者的鉴别诊断以及合并有高血压、糖尿病、血脂异常的高龄患者的随访.     

64层螺旋CT冠状动脉成像及冠状动脉彩色编码技术的临床应用

目的探讨64层螺旋CT冠状动脉成像及冠状动脉彩色编码技术在冠心病诊断的临床应用。方法对74例临床拟诊冠心病的患者进行64层螺旋CT冠状动脉成像检查。重建冠状动脉图像,显示冠状动脉分支血管,测量冠状动脉狭窄程度、长度;对检出的86段粥样硬化斑块采用彩色编码技术进行标记和测算。结果64层螺旋CT冠状动脉成像受心率影响较大,在控制心率≤70次／min时,冠状动脉1-13段血管97．4％（823／845）图像质量为1级,粥样硬化斑块及冠状动脉狭窄清晰显示。彩色编码技术检出不稳定斑块27块,其中19个斑块导致冠状动脉26％～50％狭窄,5个斑块导致冠状动脉51％-75％狭窄。结论64层螺旋CT冠状动脉成像及冠状动脉彩色编码技术可以非创伤性地显示冠状动脉狭窄程度及导致冠状动脉狭窄的斑块中各成分形态、分布及比例,可作为对冠心病患者进行筛查及初步预后评估的首选方法。     

64-slice computed tomography coronary angiography in patients with high, intermediate, or low pretest probability of significant coronary artery disease.

OBJECTIVES: We assessed the usefulness of 64-slice computed tomography coronary angiography (CTCA) to detect or rule out coronary artery disease (CAD) in patients with various estimated pretest probabilities of CAD. BACKGROUND: The pretest probability of the presence of CAD may impact the diagnostic performance of CTCA. METHODS: Sixty-four-slice CTCA (Sensation 64, Siemens, Forchheim, Germany) was performed in 254 symptomatic patients. Patients with heart rates > or =65 beats/min received beta-blockers before CTCA. The pretest probability for significant CAD was estimated by type of chest discomfort, age, gender, and traditional risk factors and defined as high (> or =71%), intermediate (31% to 70%), and low (< or =30%). Significant CAD was defined as the presence of at least 1 > or =50% coronary stenosis on quantitative coronary angiography, which was the standard of reference. No coronary segments were excluded from analysis. RESULTS: The estimated pretest probability of CAD in the high (n = 105), intermediate (n = 83), and low (n = 66) groups was 87%, 53%, and 13%, respectively. The diagnostic performance of the computed tomography (CT) scan was different in the 3 subgroups. The estimated post-test probability of the presence of significant CAD after a negative CT scan was 17%, 0%, and 0% and after a positive CT scan was 96%, 88%, and 68%, respectively. CONCLUSIONS: Computed tomography coronary angiography is useful in symptomatic patients with a low or intermediate estimated pretest probability of having significant CAD, and a negative CT scan reliably rules out the presence of significant CAD. Computed tomography coronary angiography does not provide additional relevant diagnostic information in symptomatic patients with a high estimated pretest probability of CAD.     

Relation of thoracic aorta calcification on computed tomography and coronary risk factors to obstructive coronary artery disease on angiography

The aim of this study was to investigate whether thoracic aorta calcification (TAC) on computed tomography (CT) and coronary risk factors had any correlation with obstructive coronary artery disease (CAD) on angiography. A total of 225 consecutive Japanese patients underwent both thoracic conventional helical CT and coronary angiography. The thoracic aorta was divided into 4 locations according to the aortic anatomy (inner curve of the aortic arch, aortic arch but not on the inner curve, ascending aorta, and thoracic descending aorta). The classified TAC and coronary risk factors were evaluated for the presence or absence of obstructive CAD. TAC was detected in 185 patients; 141 of 225 patients had significant obstructive CAD. All of the 13 patients with no TAC and no coronary risk factors had no CAD. The obstructive CAD rate with 1 thoracic calcified location and with no, 1, or 2 coronary risk factors was 10%, 58%, and 90%, respectively, and each showed a significant difference (p < 0.0001). The combinations of TAC and coronary risk factors with obstructive CAD were 1 or 2 thoracic calcified locations with 3 coronary risk factors, and 3 thoracic calcified locations with more than 2 coronary risk factors. Increasing thoracic calcified locations and increasing coronary risk factors indicated a higher likelihood of CAD.     

Multimodality imaging in coronary artery disease – “The more the better?”

Multimodality imaging in coronary artery disease (CAD) comprises a combination of information from more than one imaging technique. These combinations, performed in a side-by-side or fusion mode, include computed tomography (CT) and single photon emission computed tomography (SPECT), positron emission tomography (PET) and CT, and PET with magnetic resonance imaging (MRI). Data thus obtained lead to either a summative or synergistic gain of information. For instance, morphology (coronary plaques/stenosis) can be depicted by coronary CT angiography, whereas functional aspects of CAD such as myocardial perfusion abnormalities or myocardial metabolism can be evaluated by the complementary technique in order to separate a hemodynamic significant coronary stenosis from a hemodynamic non-significant stenosis. Distinguishing these two entities has an important impact on patient management. Beyond the diagnostic yield, some of these combinations in multimodality imaging also have prognostic implications. In this article, we will describe different multimodality imaging approaches (CT/SPECT, PET/CT and PET/MRI) for evaluation of CAD in patients with suspected or known CAD and put them into the context of current knowledge.     

Relation of diagonal ear lobe crease to the presence, extent, and severity of coronary artery disease determined by coronary computed tomography angiography

Controversy exists concerning the relation between diagonal ear lobe crease (DELC) and coronary artery disease (CAD). We examined whether DELC is associated with CAD using coronary computed tomography (CT) angiography. We studied 430 consecutive patients without a history of coronary artery intervention who underwent CT angiography on a dual-source scanner. Presence of DELC was agreed by 2 blinded observers. Two blinded readers evaluated CT angiography images for presence of CAD and for significant CAD (≥50% stenosis). Chi-square and t tests were used to assess demographic differences between subgroups with and without DELC and the relation of DELC to 4 measurements of CAD: any CAD, significant CAD, multivessel disease (cutoff ≥2), and number of segments with plaque (cutoff ≥3). Multivariable logistic regression was performed to adjust for CAD confounders: age, gender, symptoms, and CAD risk factors. Mean age was 61 ± 13 and 61% were men. DELC was found in 71%, any CAD in 71%, and significant CAD in 17% of patients. After adjusting for confounders, DELC remained a significant predictor of all 4 measurements of CAD (odds ratio 1.8 to 3.3, p = 0.002 to 0.017). Sensitivity, specificity, and positive and negative predictive values for DELC in detecting any CAD were 78%, 43%, 77%, and 45%. Test accuracy was calculated at 67%. Area under the receiver operator characteristic curve was 61% (p = 0.001). In conclusion, in this study of patients imaged with CT angiography, finding DELC was independently and significantly associated with increased prevalence, extent, and severity of CAD.     

Cardiac PET,CT, and MR: What Are the Advantages of Hybrid Imaging?

Cardiac hybrid imaging combines different imaging modalities in a way where both modalities equally contribute to image information. Hybrid positron emission tomography-computed tomography (PET-CT) imaging is a promising tool for evaluation of coronary artery disease (CAD) because it enables detection of coronary atherosclerotic lesions by CT angiography and their consequences on myocardial blood flow by PET perfusion in a single study. This appears to offer superior diagnostic accuracy in patients with intermediate risk for CAD compared with stand-alone imaging. Novel, commercially available hybrid scanners containing PET and magnetic resonance as well as development of targeted probes to evaluate molecular and cellular disease mechanisms are expected to provide many new applications for cardiac hybrid imaging. This article focuses on the advantages of cardiac hybrid imaging in the detection of CAD in light of currently available clinical data and discusses the potential future applications.     

Safety and efficacy of dual‐axis rotational coronary angiography vs. standard coronary angiography

Objective: To determine the safety and efficacy of dual‐axis rotational coronary angiography (DARCA) by directly comparing it to standard coronary angiography (SA). Background: Standard coronary angiography (SA) requires numerous fixed static images of the coronary tree and has multiple well‐documented limitations. Dual‐axis rotational coronary angiography (DARCA) is a new rotational acquisition technique that entails simultaneous LAO/RAO and cranial/caudal gantry movement. This technological advancement obtains numerous unique images of the left or right coronary tree with a single coronary injection. We sought to assess the safety and efficacy of DARCA as well as determine DARCA's adequacy for CAD screening and assessment. Methods: Thirty patients underwent SA following by DARCA. Contrast volume, radiation dose (DAP) and procedural time were recorded for each method to assess safety. For DARCA acquisitions, blood pressure (BP), heart rate (HR), symptoms and any arrhythmias were recorded. All angiograms were reviewed for CAD screening adequacy by two independent invasive cardiologists. Results: Compared to SA, use of DARCA was associated with a 51% reduction in contrast, 35% less radiation exposure, and 18% shorter procedural time. Both independent reviewers noted DARCA to be at least equivalent to SA with respect to the ability to screen for CAD. Conclusion: DARCA represents a new angiographic technique which is equivalent in terms of image quality and is associated with less contrast use, radiation exposure, and procedural time than SA. © 2011 Wiley‐Liss, Inc.     

A normal stress SPECT scan is an effective gatekeeper for coronary angiography.

BACKGROUND: The effectiveness of stress single photon emission computed tomography (SPECT) as a gatekeeper for coronary angiography has not been extensively investigated. The characteristics of patients referred for early angiography after a normal stress SPECT study have not been described. METHODS AND RESULTS: Over a 10-year period, 14,273 patients without documented coronary artery disease (CAD) underwent stress SPECT. Images were abnormal in 47% and normal in 53%. The overall survival rate at 15 years was 55% for patients with abnormal images versus 71% for those with normal images (P < .001). Early coronary angiography (< or =3 months) was performed in only 97 patients (1.3%) with normal SPECT studies versus 1,756 patients (26%) with abnormal SPECT studies (P < .001). Most patients with normal SPECT studies referred for early angiography (85%) had clinical, exercise, or scintigraphic findings worrisome for CAD. Two thirds of these highly selected patients with normal SPECT studies who underwent angiography did not have significant CAD; the remaining one third had primarily 1- and 2-vessel CAD. CONCLUSIONS: Stress SPECT is an effective gatekeeper for coronary angiography. The annual overall mortality rate for patients with normal images was 1.9%. Only 1.3% of patients with normal images were referred for early angiography.     

Diagnostic accuracy of dual-source multi-slice CT-coronary angiography in patients with an intermediate pretest likelihood for coronary artery disease.

AIMS: The aim of the present study was to assess the clinical performance of a dual X-ray source multi-slice CT (MSCT) with high temporal resolution to assess the coronary status in patients with an intermediate pretest likelihood for significant coronary artery disease (CAD) without using negative chronotropic pretreatment. METHODS AND RESULTS: Dual-source CT (DSCT) angiography (Siemens Definition) was performed in 90 patients with an intermediate likelihood for CAD who were referred for invasive coronary angiography. DSCT generated data sets with diagnostic image quality in 88 of the overall 90 patients. In six of seven patients with atrial fibrillation and in 46 of 48 patients with heart rates (HR)>65 b.p.m. image quality was diagnostic. In 20 of 21 patients with at least one stenosis>50% (sensitivity 95%) were correctly identified by DSCT-angiography. In 60 of 67 patients, a lesion>50% was correctly excluded (specificity 90%; positive predictive value 74%). The accuracy to detect patients with coronary stenoses>50% (sensitivity 92 vs. 100%; specificity 88 vs. 91%) was not significantly different among patients with HR>65 b.p.m. (n=46) and <65 b.p.m. The concordance of DSCT-derived stenosis quantification showed good correlation (r=0.76; P<0.001) to quantitative coronary angiography with a slight trend to overestimate the stenosis degree. CONCLUSION: DSCT is a non-invasive tool that allows to accurately rule out coronary stenoses in patients with an intermediate pretest likelihood for CAD, independent of the HR.     

Complementary results of computed tomography and magnetic resonance imaging of the heart and coronary arteries: a review and future outlook

MR and CT imaging are emerging as promising complementary imaging modalities in the primary diagnosis of CAD and for the detection of subclinical atherosclerotic disease. For the detection or exclusion of significant CAD, both cardiac CT (including coronary calcium screening and non-invasive coronary angiography), and cardiac MRI (using stress function and stress perfusion imaging) are becoming widely available for routine clinical evaluation. Their high negative predictive value, especially when combining two or more of these modalities, allows the exclusion of significant CAD with high certainty, provided that patients are selected appropriately. The primary goal of current investigations using this combined imaging approach is to reduce the number of unnecessary diagnostic coronary catheterizations, and not to replace cardiac catheterization altogether. For the diagnosis of obstructive coronary atherosclerosis and for screening for subclinical disease, CT and MRI have shown potential to directly image the atherosclerotic lesion, measure atherosclerotic burden, and characterize the plaque components. The information obtained may be used to assess progression and regression of atherosclerosis and may open new areas for diagnosis, prevention, and treatment of coronary atherosclerosis. Further clinical investigation is needed to define the technical requirements for optimal imaging, develop accurate quantitative image analysis techniques, outline criteria for image interpretation, and define the clinical indications for both MR or CT imaging. Additional studies are also needed to address the cost effectiveness of such a combined approach versus other currently available imaging modalities.