Classification of noncalcified coronary atherosclerotic plaque components on CT coronary angiography: impact of vascular attenuation and density thresholds.

PURPOSE: The authors assessed the effect of vascular attenuation and density thresholds on the classification of noncalcified plaque by computed tomography coronary angiography (CTCA). MATERIALS AND METHODS: Thirty patients (men 25; age 59 ± 8 years) with stable angina underwent arterial and delayed CTCA. At sites of atherosclerotic plaque, attenuation values (HU) were measured within the coronary lumen, noncalcified and calcified plaque material and the surrounding epicardial fat. Based on the measured CT attenuation values, coronary plaques were classified as lipid rich (attenuation value below the threshold) or fibrous (attenuation value above the threshold) using 30-HU, 50-HU and 70-HU density thresholds. RESULTS: One hundred and sixty-seven plaques (117 mixed and 50 noncalcified) were detected and assessed. The attenuation values of mixed plaques were higher than those of exclusively noncalcified plaques in both the arterial (148.3 ± 73.1 HU vs. 106.2 ± 57.9 HU) and delayed (111.4 ± 50.5 HU vs. 64.4 ± 43.4 HU) phases (p<0.01). Using a 50-HU threshold, 12 (7.2%) plaques would be classified as lipid rich on arterial scan compared with 28 (17%) on the delayed-phase scan. Reclassification of these 16 (9.6%) plaques from fibrous to lipid rich involved 4/30 (13%) patients. CONCLUSIONS: Classification of coronary plaques as lipid rich or fibrous based on absolute CT attenuation values is significantly affected by vascular attenuation and density thresholds used for the definition.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data in NSTEMI acute coronary syndrome and influence of gender and risk factors.

PURPOSE: This study sought to evaluate the diagnostic accuracy of computed tomography coronary angiography (CTCA) for detecting significant coronary artery stenosis (≥50% lumen reduction) compared with conventional coronary angiography (CAG) in non-ST-elevation myocardial infarction-acute coronary syndrome (NSTEMI-ACS) and in subgroups selected by gender and number of risk factors (RF). MATERIALS AND METHODS: We selected from a population of 1,500 patients in a multicentre registry with NSTEMI-ACS who had undergone CTCA and CAG, (n=237; 187 men, mean age 63±10 years). Diagnostic accuracy and likelihood ratios (LR) of CTCA were assessed against CAG in the total population and subgroups (men, women: 0 RF = absence of RF, 1-2 RF = presence of one or two RF, >2 RF = presence of more than two RF). RESULTS: The prevalence of obstructive disease was 53%. In the per-patient analysis, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CTCA were 100% (men 100%; women 100%; 0 RF 100%; 1-2 RF 100%; >2 RF 100%), 95% (men 98%; women 50%; 0 RF NA% (NA, not assessable); 1-2 RF 96%; >2 RF 96%), 95% (men 98%; women 91%; 0 RF 91%; 1-2 RF 96%; >2 RF 96%), 100% (men 100%; women 100%; 0 RF NV%; 1-2 RF 100%; >2 RF 100%), respectively. The per-segment analysis showed a reduction in PPV (ranging between 56% and 67%). The per-patient LR+ ranged between 18 and 27, whereas LR-were always 0. We observed no significant differences in diagnostic accuracy between subgroups. CONCLUSIONS: CTCA is a reliable diagnostic modality with high sensitivity and NPV in NSTEMI-ACS patients who are not candidates for early revascularisation, regardless of gender and number of risk factors.

Computed tomography coronary angiography in asymptomatic patients.

PURPOSE: This study assessed the accuracy of computed tomography coronary angiography (CT-CA) for detecting significant coronary artery disease (CAD; ≥50% lumen reduction) in intermediate/high-risk asymptomatic patients. MATERIALS AND METHODS: A total of 183 consecutive asymptomatic individuals (92 men; mean age 54±11 years) with more than one major risk factor (obesity, hypertension, diabetes, hypercholesterolaemia, family history, smoking) and an inconclusive or nonfeasible noninvasive stress test result (stress electrocardiography, stress echocardiography, nuclear stress scintigraphy) underwent CT-CA in an outpatient setting. All patients underwent conventional coronary angiography (CAG) within 4 weeks. Data from CT-CA were compared with CAG regarding the presence of significant CAD (≥50% lumen reduction). RESULTS: Mean calcium score was 177±432, mean heart rate during the CT-CA scan was 58±8 bpm and the prevalence (per-patient) of obstructive CAD was 19%. CT-CA showed single-vessel CAD in 9% of patients, two-vessel CAD in 9% and three-vessel CAD in 0%. Per-patient sensitivity, specificity, positive predictive value and negative predictive value of CT-CA were 100% (90-100), 98% (96-99), 97% (85-99), 100% (97-100), respectively. Positive and negative likelihood ratios were 151 and 0, respectively. CONCLUSIONS: CT-CA is an excellent noninvasive imaging modality for excluding significant CAD in intermediate/ high-risk asymptomatic patients with inconclusive or nonfeasible noninvasive stress test.

Evaluation of a multi-atlas based method for segmentation of cardiac CTA data: a large-scale, multicenter, and multivendor study.

PURPOSE: Computed tomography angiography (CTA) is increasingly used for the diagnosis of coronary artery disease (CAD). However, CTA is not commonly used for the assessment of ventricular and atrial function, although functional information extracted from CTA data is expected to improve the diagnostic value of the examination. In clinical practice, the extraction of ventricular and atrial functional information, such as stroke volume and ejection fraction, requires accurate delineation of cardiac chambers. In this paper, we investigated the accuracy and robustness of cardiac chamber delineation using a multiatlas based segmentation method on multicenter and multivendor CTA data. METHODS: A fully automatic multiatlas based method for segmenting the whole heart (i.e., the outer surface of the pericardium) and cardiac chambers from CTA data is presented and evaluated. In the segmentation approach, eight atlas images are registered to a new patient's CTA scan. The eight corresponding manually labeled images are then propagated and combined using a per voxel majority voting procedure, to obtain a cardiac segmentation. RESULTS: The method was evaluated on a multicenter/multivendor database, consisting of (1) a set of 1380 Siemens scans from 795 patients and (2) a set of 60 multivendor scans (Siemens, Philips, and GE) from different patients, acquired in six different institutions worldwide. A leave-one-out 3D quantitative validation was carried out on the eight atlas images; we obtained a mean surface-to-surface error of 0.94 +/- 1.12 mm and an average Dice coefficient of 0.93 was achieved. A 2D quantitative evaluation was performed on the 60 multivendor data sets. Here, we observed a mean surface-to-surface error of 1.26 +/- 1.25 mm and an average Dice coefficient of 0.91 was achieved. In addition to this quantitative evaluation, a large-scale 2D and 3D qualitative evaluation was performed on 1380 and 140 images, respectively. Experts evaluated that 49% of the 1380 images were very accurately segmented (below 1 mm error) and that 29% were accurately segmented (error between 1 and 3 mm), which demonstrates the robustness of the presented method. CONCLUSIONS: A fully automatic method for whole heart and cardiac chamber segmentation was presented and evaluated using multicenter/multivendor CTA data. The accuracy and robustness of the method were demonstrated by successfully applying the method to 1420 multicenter/ multivendor data sets.

Coronary centerline extraction from CT coronary angiography images using a minimum cost path approach.

PURPOSE: The application and large-scale evaluation of minimum cost path approaches for coronary centerline extraction from computed tomography coronary angiography (CTCA) data and the development and evaluation of a novel method to reduce the user-interaction time. METHODS: A semiautomatic method based on a minimum cost path approach is evaluated for two different cost functions. The first cost function is based on a frequently used vesselness measure and intensity information, and the second is a recently proposed cost function based on region statistics. User interaction is minimized to one or two mouse clicks distally in the coronary artery. The starting point for the minimum cost path search is automatically determined using a newly developed method that finds a point in the center of the aorta in one of the axial slices. This step ensures that all computationally expensive parts of the algorithm can be precomputed. RESULTS: The performance of the aorta localization procedure was demonstrated by a success rate of 100% in 75 images. The success rate and accuracy of centerline extraction was quantitatively evaluated on 48 coronary arteries in 12 images by comparing extracted centerlines with a manually annotated reference standard. The method was able to extract 88% and 47% of the vessel center-lines correctly using the vesselness/intensity and region statistics cost function, respectively. For only the proximal part of the vessels these values were 97% and 86%, respectively. Accuracy of centerline extraction, defined as the average distance from correctly automatically extracted parts of the centerline to the reference standard, was 0.64 mm for the vesselness/intensity and 0.51 mm for the region statistics cost function. The interobserver variability was 99% for the success rate measure and 0.42 mm for the accuracy measure. Qualitative evaluation using the best performing cost function resulted in successful centerline extraction for 233 out of the 252 coronaries (92%) in 63 additional CTCA images. CONCLUSIONS: The presented results, in combination with minimal user interaction and low computation time, show that minimum cost path approaches can effectively be applied as a preprocessing step for subsequent analysis in clinical practice and biomedical research.

Clinical applications of multi-detector computed tomography coronary angiography.

Cardiac computed tomography (CT) is a fast developing technique. In 10 years it developed from investigative tool into a clinical reality. The technology drive has been the key to success for this technique which is to date the only non invasive clinical tool for coronary angiographic assessment. Technical background is quite complex and the newer solutions are aiming at reducing the scan time and the radiation dose while improving temporal resolution, contrast resolution and ultimately image quality. The key technical development has been in the late 1990, the introduction of ECG triggering/gating techniques. Spatial resolution has also been improved reaching sub-millimeter performance. The latest innovations provide fast coverage with >64 slice detectors, high spatial resolution with 0.5 mm slice thickness, high temporal resolution with <100 ms in hardware, and higher contrast resolution with the forthcoming dual-energy solutions. Recently, also dose issues have been exploited and current state of the art technology are able to perform cardiac CT with 1-2 mSv. These improvements put cardiac CT as the most promising clinical tool for the non invasive assessment of coronary arteries.

Spiral multislice computed tomography coronary angiography: a current status report.

Multislice computed tomography coronary angiography (MSCT-CA) has emerged as a powerful noninvasive diagnostic modality to visualize the coronary arteries and to detect significant coronary stenoses. The latest generation 64-slice computed tomography (CT) scanners is a robust technique which allows high-resolution, isotropic, nearly motion-free coronary imaging. Coronary stenoses are detected with high sensitivity and a normal scan accurately rules out the presence of a coronary stenosis. With the introduction of further novel concepts in CT-technology one may expect that MSCT-CA will become a clinically used diagnostic tool.

Multislice computed tomography coronary angiography: clinical applications.

Cardiac and coronary computed tomography (CT) is becoming increasingly common in clinical practice. Even if there is no well-established evidence, this diagnostic modality is so strong and effective and, in skilled hand, it can be readily used in clinical practice. After learning its potential and the technical limits, this tool could be used for risk stratification as well as for revascularization evaluation. In this review, we will describe the results of present literature, clinical applications at present considered suitable to CT technology (i.e. 64-slice and dual-source scanners) and future applications and innovations.

Non-invasive coronary angiography with 64-slice computed tomography.

Multislice computed tomography is a rapidly emerging technique for the non-invasive visualization of coronary arteries. Over the past 5 years several scanner generation were introduced with a progressive improvement in the diagnostic accuracy in the detection of coronary artery stenosis in selected patients populations. The introduction of 64-slice technology has further improved the diagnostic performance. This technique is at the edge of clinical implementation and, even though large clinical trials are still missing, an increased demand for these type of studies is observed all over the world. We describe our experience of more than 1 year with 64-slice CT coronary angiography providing clues on reasonable clinical applications.

First-line evaluation of coronary artery disease with coronary calcium scanning or exercise electrocardiography.

BACKGROUND: Although conventional (CAG) and computed tomography angiography (CTA) are reliable diagnostic modalities for exclusion of obstructive coronary artery disease (CAD), they are costly and with considerable exposure to radiation and contrast media. We compared the accuracy of coronary calcium scanning (CCS) and exercise electrocardiography (X-ECG) as less expensive and non-invasive means to rule out obstructive CAD. METHODS: In a rapid-access chest pain clinic, 791 consecutive patients with stable chest pain were planned to undergo X-ECG and dual-source CTA with CCS. According to the Duke pre-test probability of CAD patients were classified as low (<30%), intermediate (30-70%) or high risk (>70%). Angiographic obstructive CAD (>50% stenosis by CAG or CTA) was found in 210/791 (27%) patients, CAG overruling any CTA results. RESULTS: Obstructive CAD was found in 12/281 (4%) patients with no coronary calcium and in 73/319 (23%) with a normal X-ECG (p<0.001). No coronary calcium was associated with a substantially lower likelihood ratio compared to X-ECG; 0.11, 0.13 and 0.13 vs. 0.93, 0.55 and 0.46 in the low, intermediate and high risk group. In low risk patients a negative calcium score reduced the likelihood of obstructive CAD to less than 5%, removing the need for further diagnostic work-up. CCS could be performed in 754/756 (100%) patients, while X-ECG was diagnostic in 448/756 (59%) patients (p<0.001). CONCLUSIONS: In real-world patients with stable chest pain CCS is a reliable initial test to rule out obstructive CAD and can be performed in virtually all patients.

Diagnostic performance of exercise bicycle testing and single-photon emission computed tomography: comparison with 64-slice computed tomography coronary angiography.

To conduct a comparison of the diagnostic performance of exercise bicycle testing and single-photon emission computed tomography (SPECT) with computed tomography coronary angiography (CTCA) for the detection of obstructive coronary artery disease (CAD) in patients with stable angina. 376 symptomatic patients (254 men, 122 women, mean age 60.4 ± 10.0 years) referred for noninvasive stress testing (exercise bicycle test and/or SPECT) and invasive coronary angiography were included. All patients underwent additional 64-slice CTCA. The diagnostic performance of exercise bicycle testing (ST segment depression), SPECT (reversible perfusion defect) and CTCA (≥50% lumen diameter reduction) was presented as sensitivity, specificity, positive and negative predictive value (PPV and NPV) to detect or rule out obstructive CAD with quantitative coronary angiography as reference standard. Comparisons of exercise bicycle testing versus CTCA (n = 334), and SPECT versus CTCA (n = 61) were performed. The diagnostic performance of exercise bicycle testing was significantly (P value < 0.001) lower compared to CTCA: sensitivity of 76% (95% CI, 71-82) vs. 100% (95% CI, 97-100); specificity of 47% (95% CI, 36-58) vs. 74% (95% CI, 63-82). We observed a PPV of 70% (95% CI, 65-75) vs. 91% (95% CI, 87-94); and NPV of 30% (95%, 25-35) vs. 99% (95%, 90-100). There was a statistically significant difference in sensitivity (P value < 0.05) between SPECT and CTCA: 89% (95% CI, 75-96) vs. 98% (95% CI, 87-100); but not in specificity (P value > 0.05): 77% (95% CI, 50-92) vs. 82% (95% CI, 56-95). We observed a PPV of 91% (95% CI, 77-97) vs. 93% (95% CI, 81-98); and NPV of 72% (95%, 46-89) vs. 93% (95%, 66-100). SPECT and CTCA yielded higher diagnostic performance compared to traditional exercise bicycle testing for the detection and rule out of obstructive CAD in patients with stable angina.

Assessment of left main coronary artery atherosclerotic burden using 64-slice CT coronary angiography: correlation between dimensions and presence of plaques.

PURPOSE: The aim of this study was to correlate left main (LM) coronary artery dimensions with the presence of atherosclerosis by multidetector-row computed tomography (MDCT) coronary angiography (CA) and to assess coronary atherosclerotic plaques with a semiquantitative method. MATERIALS AND METHODS: Sixty-two consecutive patients (41 men, mean age 60+/-11) with suspected coronary artery disease underwent 64-MDCT coronary angiography. LM dimensions (length, ostial and bifurcation diameters), quantitative [location, Hounsfield unit (HU) attenuation] and qualitative (composition, shape) analysis of plaques within the LM were performed. All patients underwent conventional CA. RESULTS: Thirty patients (mean age 55+/-10) without plaques in the LM presented the following average dimensions: length 10.6+/-6.1 mm, ostial diameter 5.5+/-0.7 mm, bifurcation diameter 4.9+/-0.9 mm. LM plaques (n=36) were detected in 32 patients (mean age 64+/-10) with the following LM average dimensions: length 11.3+/-4.0 mm, ostial diameter 6.0+/-1.2 mm and bifurcation diameter 6.0+/-1.2 mm. Plaques were calcified (40%, mean attenuation 742+/-191 HU), mixed (43%, mean attenuation 387+/-94 HU) or noncalcified (17%, mean attenuation 56+/-14 HU) and were frequently eccentric (77%). Age was significantly different in the two groups (p<0.05). LM diameters of patients with plaques were improved (p<0.05). A moderate correlation was found between the LM bifurcation diameter and the corresponding plaque area (r=0.56). Significant conventional CA lesions of the LM were present in just three patients (5%). CONCLUSIONS: Increased LM diameters are associated with the presence of atherosclerosis. MDCT CA indicates relevant features of LM atherosclerotic burden, as rupture and subsequent thrombosis of vulnerable plaques may develop from lesions characterised as nonsignificant at conventional CA.

ECG-gated multidetector computed tomography for the assessment of the postoperative ascending aorta.

PURPOSE: This study was undertaken to define the role of electrocardiographically (ECG)-gated multidetector computed tomography (MDCT) in the assessment of the postoperative ascending aorta. MATERIALS AND METHODS: From November 2006 to June 2007, 21 patients, [11 men, ten women; age +/- standard deviation (SD): 62.7+/-10.8 years] with a history of ascending aorta replacement underwent ECG-gated MDCT and were prospectively included in our study. Ascending aorta replacement had been performed with different surgical techniques: Bentall-De Bono (four patients, 19%), Tirone-David (five patients, 23%), and modified Tirone-David with creation of aortic neosinuses (12 patients, 57%). Two patients were excluded from MDCT evaluation because they failed to fulfil the inclusion criteria. Transthoracic echocardiography was used as the reference standard. All patients provided informed consent. RESULTS: In all patients, ECG-gated MDCT provided a clear depiction of the aortic annulus, aortic root and ascending aorta, enabling accurate measurements in all cases. The aortic valve area (3.4+/-0.2 cm(2)), the diameter of the sinotubular junction (31.6+/-1.8 mm), the diameter of the neosinuses in the case of modified Tirone-David procedures (37.3+/-2.1 mm) and the distance between the cusps and the graft wall during systole (3.1+/-0.7 mm) fell within standard ranges and showed a good correlation (r=0.89) with the values obtained with transthoracic echocardiography. CONCLUSIONS: MDCT is currently considered a compulsory diagnostic step in patients with suspected or known aortic pathology. MDCT is a reliable technique for anatomical and functional assessment of the postoperative aortic root and provides cardiac surgeons with new and detailed information, enabling them to formulate a prognostic opinion regarding the outcome of the surgical procedure.

64-slice computed tomography coronary angiography: diagnostic accuracy in the real world.

PURPOSE: This study was done to evaluate the diagnostic accuracy of 64-slice computed tomography coronary angiography (CTCA) for the detection of significant coronary artery stenosis in the real clinical world. MATERIALS AND METHOD: From the CTCA database of our institution, we enrolled 145 patients (92 men, 52 women, mean age 63.4 +/- 10.2 years) with suspected coronary artery disease. All patients presented with atypical or typical chest pain and underwent CTCA and conventional coronary angiography (CA). For the CTCA scan (Sensation 64, Siemens, Germany), we administered an IV bolus of 100 ml of iodinated contrast material (Iomeprol 400 mgI/ml, Bracco, Italy). The CTCA and CA reports used to evaluate diagnostic accuracy adopted > or =50% and > or =70%, respectively, as thresholds for significant stenosis. RESULT: Eleven patients were excluded from the analysis because of the nondiagnostic quality of CTCA. The prevalence of disease demonstrated at CA was 63% (84/134). Sensitivity, specificity and positive and negative predictive values for CTCA on a per-segment, per-vessel, and per-patient basis were 75.6%, 85.1%, 97.6%; 86.9%, 81.8%, 58.0%; 48.2%, 68.1%, 79.6%; and 95.7%, 92.3%, 93.5%, respectively. Only two out of 134 eligible patients were false negative. Heart rate did not significantly influence diagnostic accuracy, whereas the absence or minimal presence of coronary calcification improved diagnostic accuracy. The positive and negative likelihood ratios at the per-patient level were 2.32 and 0.041, respectively. CONCLUSION: CTCA in the real clinical world shows a diagnostic performance lower than reported in previous validation studies. The excellent negative predictive value and negative likelihood ratio make CTCA a noninvasive gold standard for exclusion of significant coronary artery disease.

Prevalence and characteristics of coronary artery disease in a population with suspected ischemic heart disease using CT coronary angiography: correlations with cardiovascular risk factors and clinical presentation.

PURPOSE: This study was undertaken to describe the correlation between the distribution of coronary artery disease (CAD) in a symptomatic population with suspected ischaemic heart disease, cardiovascular risk factors (RF) and clinical presentation. MATERIALS AND METHODS: we studied 163 patients (mean age 65.5 years; 101 men and 62 women) referred for multidetector computed tomography coronary angiography (MDCT-CA) to rule out CAD. The patients had no prior history of revascularisation or myocardial infarction. We analysed how the characteristics of CAD (severity and type of plaque) can change with the increase in RF and how they are related to different clinical presentations. RESULTS: patients were divided into three groups according to the number of RF: zero or one, two or three, and four or more. The percentage of coronary arteries with no plaque, nonsignificant disease and significant disease was 55%, 41% and 4%, respectively, in patients with zero or one RF; 27%, 51% and 22%, respectively, in patients with two or three RF; and 19%, 38% and 44%, respectively, in patients with four or more RF. Plaque in patients with nonsignificant disease was mixed in 65%, soft in 18% and calcified in 17%. The percentage of coronaries with no plaque in the three RF groups was 50%, 20% and 0% in patients with typical chest pain and 46%, 24% and 12% in those with atypical pain. The percentage of significant disease in patients with typical pain was 0%, 47% and 86% and in those with atypical pain 4%, 20% and 29%. CONCLUSIONS: MDCT plays an important role in the identification of CAD in patients with suspected ischaemic heart disease. Severity and type of disease is highly correlated with RF number and assumes different characteristics according to clinical presentation.

Dual source coronary computed tomography angiography for detecting in-stent restenosis.

OBJECTIVE: To evaluate the performance of dual source CT coronary angiography (DSCT-CA) in the detection of in-stent restenosis (>or=50% luminal narrowing) in symptomatic patients referred for conventional angiography (CA). DESIGN/ PATIENTS: 100 patients (78 males, age 62 (SD 10)) with chest pain were prospectively evaluated after coronary stenting. DSCT-CA was performed before CA. SETTING: Many patients undergo coronary artery stenting; availability of a non-invasive modality to detect in-stent restenosis would be desirable. RESULTS: Average heart rate (HR) was 67 (SD 12) (range 46-106) bpm. There were 178 stented lesions. The interval between stenting and inclusion in the study was 35 (SD 41) (range 3-140) months. 39/100 (39%) patients had angiographically proven restenosis. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of DSCT-CA, calculated in all stents, were 94%, 92%, 77% and 98%, respectively. Diagnostic performance at HR <70 bpm (n = 69; mean 58 bpm) was similar to that at HR >or=70 bpm (n = 31; mean 78 bpm); diagnostic performance in single stents (n = 95) was similar to that in overlapping stents and bifurcations (n = 83). In stents >or=3.5 mm (n = 78), sensitivity, specificity, PPV, NPV were 100%; in 3 mm stents (n = 59), sensitivity and NPV were 100%, specificity 97%, PPV 91%; in stents or=3.5 mm was significantly higher than in stents

Coronary variants and anomalies: methodology of visualisation with 64-slice CT and prevalence in 202 consecutive patients.

PURPOSE: This paper aims to provide the tools for a complete anatomical evaluation of the coronary tree using 64-slice computed tomography (CT) and evaluate the prevalence of anatomical variants and anomalies in a population of 202 consecutive patients. MATERIALS AND METHODS: Two hundred and two patients with suspected coronary artery disease underwent 64-slice CT with a standard protocol. Two observers working in consensus evaluated and collected the data regarding anatomical variants and anomalies of the coronary vessels. RESULTS: In the 202 consecutive patients, the prevalence of anatomical variants was: left dominant circulation (7%), absent left main (5%), presence of intermediate branch (17%), aortic origin of conus branch (13%) and circumflex origin of sinus node branch (15%). Coronary anomalies (origin and course, intrinsic and termination) showed an overall prevalence of 25%. CONCLUSIONS: CT is the ideal method for the three-dimensional evaluation of the coronary tree. Anatomical variants and anomalies of the coronary arteries are quite common and should be known and recognised promptly by the operators.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in patients with low-to-intermediate risk.

PURPOSE: Our aim was to evaluate the diagnostic accuracy of 64-slice computed tomography coronary angiography (MSCT-CA) for detecting significant stenosis (>or=50% lumen reduction) in a population of patients at low to intermediate risk. MATERIALS AND METHODS: We studied 72 patients (38 men, 34 women, mean age 53.9+/-8.0 years) with atypical or typical chest pain and stratified in the low-to intermediate risk category. MSCT-CA (Sensation 64 Cardiac, Siemens, Germany) was performed after IV administration of 100 ml of iodinated contrast material (Iomeprol 400 mgI/ml, Bracco, Italy). Two observers, blinded to the results of conventional coronary angiography (CAG), assessed the MSCT-CA scans in consensus. Diagnostic accuracy for detecting significant stenosis was calculated. RESULTS: CAG demonstrated the absence of significant disease in 70.1% of patients (51/72). No patient was excluded from MSCT-CA. There were 37 significant lesions on 1,098 available coronary segments. Sensitivity, specificity and positive and negative predictive value of MSCT-CA for detecting significant coronary artery on a per-segment basis were 100%, 98.6%, 71.2% and 100%, respectively. All patients with at least one significant lesion were correctly identified by MSCT-CA. MSCT-CA scored 15 false positives on a per-segment base, which affected only marginally the per-patient performance (only one false positive). CONCLUSIONS: We concluded that 64-slice CT-CA is a diagnostic modality with high sensitivity and negative predictive value in patients at low to intermediate risk.

Spectrum of collateral findings in multislice CT coronary angiography.

PURPOSE: The aim of the study was to investigate the prevalence of the noncardiac collateral findings during multislice computed tomography coronary angiography (MSCT-CA). MATERIALS AND METHODS: Six hundred and seventy patients undergoing MSCT-CA with 16-slice and 64-slice CT scanners for suspected atherosclerotic disease of the coronary arteries were retrospectively reviewed. All data sets obtained with a large field of view (FOV) were analysed by two radiologists using standard mediastinal and lung window settings. Collateral findings were divided according to clinical importance into nonsignificant, remarkable and compulsory to be investigated. RESULTS: Eighty-five percent of patients revealed coronary artery disease (CAD). Only 138/670 (20.6%) were without any additional finding. An additional 1,234 findings were recorded: nonsignificant 332 (26.9%), mild 821 (66.53%), compulsory for study 81 (6.56%). A total of 81 patients (12.08%) had significant noncardiac pathology requiring clinical or radiological follow-up. Among these, newly discovered pathologies were revealed in two patients (2.46%). CONCLUSIONS: A significant number of noncardiac findings might have been missed in MSCT-CA scans; the appropriate approach should be as a team trained in cardiology and radiology.

Diagnostic accuracy of 64-slice CT in the assessment of coronary stents.

PURPOSE: The purpose of this study was to assess the diagnostic accuracy of 64-slice computed tomography (64-CT) coronary angiography in the detection of coronary in-stent restenosis. MATERIALS AND METHODS: Ninety-five patients (72 men and 23 women, mean age 58+/-8 years) with previous percutaneous coronary intervention with stenting and suspected restenosis underwent 64-CT (Sensation 64, Siemens). The mean time between stent deployment and 64-CT was 6.1+/-4.2 months. The scan parameters were: slices 32 x 2, individual detector width 0.6 mm, rotation time 0.33 s, feed 3.84 mm/rotation, 120 kV, 900 mAs. After the intravenous administration of iodinated contrast material (Iomeprol 400 mgI/ml, Iomeron, Bracco) and a bolus chaser (40 ml of saline), the scan was completed in <12 s. All coronary segments with a stent were assessed on 64-CT by two observers in consensus and judged as: patent, with intimal hyperplasia (lumen reduction of <50%), with in-stent restenosis (> or =50%), or with in-stent occlusion (100%). The consensus reading was compared with conventional coronary angiography. RESULTS: Four patients were excluded because of insufficient image quality. In the remaining 91, we assessed 102 stents (31 RCA; 10 LM; 54 LAD; 7 CX). In 14 (13.7%) stents, in-stent restenosis (n=8) or in-stent occlusion (n=6) was found. Intimal hyperplasia was detected in 11 (10.8%) stents. The sensitivity and negative predictive value of 64-CT for in-stent occlusion were 100% and 100%, respectively, whereas for all stenoses, >50% they were 92.9% and 98.7%, respectively. CONCLUSIONS: We found that 64-CT has a high diagnostic accuracy for the detection of in-stent restenosis in a selected patient population.