64-slice Multislice Computed Tomography Research Articles

The relationship between the coronary sinus and coronary artery using multislice spiral computed tomography and conventional invasive angiography

Background Multislice computed tomography (MSCT) has been used extensively for coronary artery imaging. To understand the relationship between coronary artery and coronary sinus (CS) anatomy in patients undergoing electrophysiological study, conventional invasive angiography is typically performed. The purpose of this study was to image the coronary artery and CS and its tributaries using MSCT, in comparison with invasive angiography. Methods and results The study consisted of 141 patients (83 men, 58 women; age 52 ± 10 years) who underwent 64-slice MSCT and 3D reconstruction and invasive coronary artery and CS angiography before radiofrequency catheter ablation. The cardiac venous system and coronary artery were visualized in all patients by MSCT and invasive angiography. All data of angiography and MSCT were measured via the same projection (right or left anterior oblique). Angiography and MSCT result revealed coronary arteries of all patients with a vessel diameter over 1 mm. The CS and the middle cardiac vein (MCV) were observed in all patients. MSCT provided high accuracy for the MCV to the CS ostium (CSO), the posterior interventricular vein (PIV) to CSO, and the mean diameter of MCV, PIV and CS ostia, compared with invasive angiography ( p < 0.001). Conclusions MSCT was a reliable tool to visualize the relationship between the coronary artery and CS and its tributaries. MSCT may improve the procedural success rate and reduce the complication rate in patients undergoing electrophysiological study.

Volumetric evaluation of coronary plaque in patients presenting with acute myocardial infarction or stable angina pectoris—a multislice computerized tomography study

We hypothesized that unstable clinical presentation of coronary artery disease is associated with distinct characteristics of culprit lesions identifiable by multislice computed tomography (MSCT). Patients with non-ST-elevation myocardial infarction (NSTEMI) (n = 57) or stable angina (SA) pectoris (n = 19) were studied. Coronary culprit lesions in patients with NSTEMI and symptomatic lesions in patients with SA were evaluated with 64-slice MSCT and a volumetric plaque imaging tool. Plaque volumes of lipid, fibrous tissue, or calcification according to signal intensity were determined. Plaque burden, mean signal intensity of the lesions, relative volumetric distribution of plaque components, and remodeling index were measured. Volumetric plaque burden of study lesions were similar in the 2 patient groups (P = .38). Mean signal intensity of study lesions were lower in patients with NSTEMI compared with patients with SA (74 [66-97] Hounsfield units vs 99 [77-154] Hounsfield units, P = .02). The volume of plaque occupied by calcified material was lower in patients with NSTEMI compared with patients with SA (15 mm(3) [3-58 mm(3)] vs 42 mm(3) [18-82 mm(3)], P = .045). In patients with NSTEMI, the lipid-rich plaque subtype was more frequent than in patients with SA, and the calcified plaque subtype was less frequent in patients with NSTEMI than in patients with SA (P = .032). Positive remodeling was observed in 19% of patients with NSTEMI, whereas this was absent in patients with SA (P = .04). Volumetric measurements with MSCT revealed that coronary culprit lesions in acute coronary syndrome frequently display low mean plaque signal intensity values, lipid-rich plaque subtype, and positive remodeling.

Prevalence of left main coronary artery disease among patients referred to multislice computed tomography coronary examinations

We have evaluated the prevalence of left main coronary artery disease (LMCAD) among patients referred to multislice computed tomography (MSCT) coronary angiography examinations. The study Group comprised of 1,000 consecutive patients (750 male and 250 female; mean age 53+/-12 years) who underwent successful 64-slice MSCT examinations. Left main coronary artery (LMCA) was classified into three Groups: normal LMCA; nonsignificant LMCAD with coronary plaques resulting in obstructions <or=50%; and significant LMCAD corresponding to obstructions >50%. We have found that 24 patients (2.4%) had significant LMCAD. Additional 200 patients (20%) had nonsignificant LMCAD. Univariate analysis revealed that LMCAD was associated with age, male gender, diabetes, hypertension, hyperlipidemia, typical symptoms, history of previous myocardial infarction and previous percutaneous coronary intervention. Only age and male gender were found as independent predictors for LMCAD in multivariate analysis (P < 0.001 and P = 0.001, respectively,). Angiographic follow-up was avaliable for the 24 patients with significant LMCAD, and conventional coronary angiography confirmed the presence of significant LMCAD in all of these patients. Significant LMCAD was found in 2.4% of the 1,000 patients referred to 64-slice MSCT examinations. Age and male gender were the independent predictors for LMCAD.

Quantitative parameters to compare image quality of non-invasive coronary angiography with 16-slice, 64-slice and dual-source computed tomography

Multi-slice computed tomography (MSCT) is a non-invasive modality to visualize coronary arteries with an overall good image quality. Improved spatial and temporal resolution of 64-slice and dual-source computed tomography (DSCT) scanners are supposed to have a positive impact on diagnostic accuracy and image quality. However, quantitative parameters to compare image quality of 16-slice, 64-slice MSCT and DSCT are missing. A total of 256 CT examinations were evaluated (Siemens, Sensation 16: n = 90; Siemens Sensation 64: n = 91; Siemens Definition: n = 75). Mean Hounsfield units (HU) were measured in the cavum of the left ventricle (LV), the ascending aorta (Ao), the left ventricular myocardium (My) and the proximal part of the left main (LM), the left anterior descending artery (LAD), the right coronary artery (RCA) and the circumflex artery (CX). Moreover, the ratio of intraluminal attenuation (HU) to myocardial attenuation was assessed for all coronary arteries. Clinical data [body mass index (BMI), gender, heart rate] were accessible for all patients. Mean attenuation (CA) of the coronary arteries was significantly higher for DSCT in comparison to 64- and 16-slice MSCT within the RCA [347 +/- 13 vs. 254 +/- 14 (64-MSCT) vs. 233 +/- 11 (16-MSCT) HU], LM (362 +/- 11/275 +/- 12/262 +/- 9), LAD (332 +/- 17/248 +/- 19/219 +/- 14) and LCX (310 +/- 12/210 +/- 13/221 +/- 10, all p < 0.05), whereas there was no significant difference between DSCT and 64-MSCT for the LV, the Ao and My. Heart rate had a significant impact on CA ratio in 16-slice and 64-slice CT only (p < 0.05). BMI had no impact on the CA ratio in DSCT only (p < 0.001). Improved spatial and temporal resolution of dual-source CT is associated with better opacification of the coronary arteries and a better contrast with the myocardium, which is independent of heart rate. In comparison to MSCT, opacification of the coronary arteries at DSCT is not affected by BMI. The main advantage of DSCT lies with the heart rate independency, which might have a positive impact on the diagnostic accuracy.

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

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

Evaluation of plaque characteristics in acute coronary syndromes: non-invasive assessment with multi-slice computed tomography and invasive evaluation with intravascular ultrasound radiofrequency data analysis

Atherosclerotic plaque characteristics play an important role in the development of coronary events. We investigated coronary plaque characteristics on multi-slice computed tomography (MSCT) and virtual histology intravascular ultrasound (VH IVUS) in patients with acute coronary syndromes (ACS) and stable coronary artery disease (CAD). Fifty patients (25 with ACS, 25 with stable CAD) underwent 64-slice MSCT followed by VH IVUS in 48 (96%) patients. In ACS patients, 32% of plaques were non-calcified on MSCT and 59% were mixed [corresponding odds ratio (95% confidence intervals): 3.9 (1.6-9.5), P = 0.003 and 3.4 (1.6-6.9), P = 0.001, respectively]. In patients with stable CAD, completely calcified lesions were more prevalent (61%). On VH IVUS, the percentage of necrotic core was higher in the plaques of ACS patients (11.16 +/- 6.07 vs. 9.08 +/- 4.62% in stable CAD, P = 0.02). In addition, thin cap fibroatheroma was more prevalent in ACS patients (32 vs. 3% in patients with stable CAD, P < 0.001) and was most frequently observed in mixed plaques on MSCT. Plaque composition both on MSCT and VH IVUS was identical between culprit and non-culprit vessels of ACS patients. On MSCT, differences in plaque characterization were demonstrated between patients with ACS and stable CAD. Plaques of ACS patients showed features of vulnerability to rupture on VH IVUS. Potentially, MSCT may be useful for non-invasive identification of atherosclerotic plaque patterns associated with higher risk.

Accuracy of Multislice Computed Tomography Coronary Angiography

A PUBMED search was performed for peer-reviewed studies published in English from 2002 through August 2006. Accuracy parameters for detection of obstructive coronary artery disease by MSCT (multislice computed tomography) coronary angiography were analyzed on patient and segment basis. Pooled estimates of sensitivity (SN), specificity, positive predictive value, and negative predictive value (NPV) in patient-based analyses were 93%, 82%, 83%, and 92%, respectively. For 64/40-slice MSCT the respective accuracy estimates were 96%, 91%, 93%, and 96% and were better compared with 16-slice MSCT. Also, more segments were evaluated by 64-slice MSCT (96%) compared with 16-slice MSCT (86%). The SN and NPV of MSCT coronary angiography for patients with low coronary artery calcium (CAC) score were 92% and 99% compared with 77% and 89% for patients with high CAC score. The accuracy estimates for MSCT in studying coronary artery by-pass grafts and intracoronary stents showed a SN and NPV of 97% and 97% for graft occlusion or stenosis and only 71% and 93% respectively for in-stent restenosis. Diagnostic accuracy of MSCT coronary angiography has improved with the newer 64-slice versions. High CAC scores can affect the accuracy of MSCT coronary angiography. Although the accuracy of MSCT in evaluating native vessel and graft disease has improved significantly, its reliability in studying intracoronary stents remains uncertain.

Coronary Computed Tomography Angiography—A Promising Imaging Modality in Diagnosing Coronary Artery Disease

Traditionally, information on coronary artery lesions is obtained from invasive coronary angiography (CAG). The clinical applicability and diagnostic performance of the newly developed 64-slice multislice computed tomography (MSCT) scanner in coronary angiographic evaluation is not well evaluated. Coronary computed tomography angiography (CCTA) was performed in 345 patients (119 women, 226 men; mean age, 59.64 +/- 11.67 years). Concomitant CAG was performed in 53 patients. The diagnostic performance of CCTA for detecting significant lesions was compared with that of CAG by 3 independent cardiologists. All CCTA was performed without complication. Comparison between CCTA and CAG was made in the 53 patients who underwent both studies. Sensitivity, specificity and the positive and negative predictive values for the 53 patients were: 81%, 99%, 87% and 99%, respectively. The 64-slice MSCT, developed in recent years, allows reliable noninvasive evaluation of coronary artery morphology, including plaque, stenosis and congenital anomaly. The diagnostic accuracy of MSCT scans for detecting lesions makes it a good imaging substitute for CAG in the evaluation of these coronary segments.

Noninvasive Evaluation of the Aortic Root With Multislice Computed Tomography: Implications for Transcatheter Aortic Valve Replacement

In the present study, the anatomy of the aortic root was assessed noninvasively with multislice computed tomography (MSCT). Transcatheter aortic valve replacement has been proposed as an alternative to surgery in high-risk patients with severe aortic stenosis. For this procedure, detailed knowledge of aortic annulus diameters and the relation between the annulus and the coronary arteries is needed. In 169 patients (111 men, age 54 +/- 11 years), a 64-slice MSCT scan was performed for evaluation of coronary artery disease. Of these, 150 patients had no or mild aortic stenosis, and 19 patients had moderate to severe aortic stenosis. Reconstructed coronal and sagittal views were used for assessment of the aortic annulus diameter in 2 directions. In addition, the distance between the annulus and the ostium of the right and left coronary arteries and the length of the coronary leaflets were assessed. The LV outflow tract and interventricular septum were analyzed on the single oblique sagittal view at end-diastole. The diameter of the aortic annulus was 26.3 +/- 2.8 mm on the coronal view, and 23.5 +/- 2.7 mm on the sagittal view. Mean difference between the 2 diameters was 2.9 +/- 1.8 mm, indicating an oval shape of the aortic annulus. Mean distance between the aortic annulus and the ostium of the right coronary artery was 17.2 +/- 3.3 mm, and mean distance between the annulus and the ostium of the left coronary artery was 14.4 +/- 2.9 mm. In 82 patients (49%), the length of the left coronary leaflet exceeded the distance between the annulus and the ostium of the left coronary artery. There were no significant differences in the diameter of annulus, diameter of sinus of Valsalva, or the distance between the annulus, left coronary leaflet, and the ostium of the left coronary artery, between the patient with and without severe aortic stenosis. The MSCT can provide detailed information on the shape of the aortic annulus and the relation between the annulus and the ostia of the coronary arteries. Thereby, MSCT may be helpful for avoiding paravalvular leakage and coronary occlusion and may facilitate the selection of candidates for transcatheter aortic valve replacement.

Head-to-Head Comparison of Coronary Plaque Evaluation Between Multislice Computed Tomography and Intravascular Ultrasound Radiofrequency Data Analysis

The purpose of this study was to perform a head-to-head comparison of plaque observations with multislice computed tomography (MSCT) to virtual histology intravascular ultrasound (VH IVUS). The VH IVUS allows in vivo coronary plaque characterization with high spatial resolution. Noninvasively, plaques may be evaluated with MSCT, but limited data are available. A total of 50 patients underwent 64-slice MSCT followed by VH IVUS. The Agatston score was evaluated on MSCT in coronary segments where IVUS was performed. Plaques were classified on MSCT as noncalcified, mixed, and calcified. Four plaque components (fibrotic, fibro-fatty, and necrotic core tissues and dense calcium) were identified on VH IVUS, and the presence of thin-cap fibroatheroma was evaluated. A moderate correlation was observed between the Agatston score and calcium volume on VH IVUS (r = 0.69, p < 0.0001). In total, 168 coronary plaques were evaluated (48 [29%] noncalcified, 71 [42%] mixed, 49 [29%] calcified). As compared with calcified plaques, noncalcified plaques contained more fibrotic (60.90 +/- 9.21% vs. 54.60 +/- 8.33%, p = 0.001) and fibro-fatty tissues (28.11 +/- 13.03% vs. 21.37 +/- 9.75%, p = 0.006) on VH IVUS. Mixed and calcified plaques contained more dense calcium (7.61 +/- 8.94% vs. 2.68 +/- 3.01%, p = 0.001; 10.18 +/- 6.71% vs. 2.68 +/- 3.01%, p < 0.0001, respectively). Thin-cap fibroatheromas were most frequently observed in mixed plaques as compared with noncalcified and calcified plaques (32%, 13%, 8%, p = 0.002, respectively). A good correlation was observed between calcium quantification on MSCT and VH IVUS. In addition, plaque classification on MSCT paralleled relative plaque composition on VH IVUS, although VH IVUS provided more precise plaque characterization. Mixed plaques on MSCT were associated with high-risk features on VH IVUS.

Noninvasive Imaging of Cardiac Venous Anatomy With 64-Slice Multi-Slice Computed Tomography and Noninvasive Assessment of Left Ventricular Dyssynchrony by 3-Dimensional Tissue Synchronization Imaging in Patients With Heart Failure Scheduled for Cardiac Resynchronization Therapy

Objectives of this study were to perform a prospective head-to-head comparison between multi-slice computed tomography (MSCT) venography and invasive venography in cardiac resynchronization therapy (CRT) candidates as well as to evaluate the relation between left ventricular (LV) lead position and effect on LV dyssynchrony and immediate response to CRT. Twenty-one consecutive heart failure patients scheduled for CRT implantation were prospectively enrolled to undergo 64-slice MSCT to visualize the venous system, invasive venography during device implantation, and tri-plane tissue synchronization imaging (TSI) before and after implantation. Excellent agreement between MSCT and invasive venography was noted. No significant differences were observed between both techniques regarding vessel diameters. In 12 patients, a match was observed between the area of latest mechanical activation (on TSI) and LV lead position. These patients showed a significant decrease in LV dyssynchrony (43 +/- 7 ms to 11 +/- 9 ms, p <0.0001) with acute reduction in LV end-systolic volume (188 +/- 54 ml to 162 +/- 48 ml, p <0.01) and improvement in LV ejection fraction (22% +/- 9% to 34% +/- 9%, p <0.01). Patients with a mismatch between area of latest activation and LV lead position remained dyssynchronous without improvement in LV function. In conclusion, visualization of major tributaries of the coronary sinus was comparable between invasive venography and MSCT venography. Optimal LV lead positioning in a vein draining the area of latest mechanical activation (determined from tri-plane TSI) resulted in acute improvement of LV dyssynchrony and systolic function after CRT implantation.

Anatomic Correlates of a Normal Perfusion Scan Using 64-Slice Computed Tomographic Coronary Angiography

Both myocardial perfusion imaging (MPI) and multislice computed tomography (MSCT) are currently used to detect coronary artery disease (CAD). However, MSCT permits early detection of atherosclerosis while myocardial perfusion is still normal. In addition, MPI results can be normal despite the presence of high-risk CAD (left main and balanced 3-vessel CAD). In this study, the range of anatomic findings using MSCT in patients with normal MPI results was evaluated. In 180 patients presenting with chest pain, MPI (with gated single-photon emission computed tomography) and 64-slice MSCT were performed. In patients with normal MPI results, prevalences of completely normal coronary arteries, nonobstructive CAD, and obstructive CAD were determined using MSCT. The occurrence of high-risk CAD, including left main and 3-vessel disease, was also evaluated. Normal MPI and adequate MSCT findings were obtained in 97 patients (54%; 50% women; average age 58 +/- 12 years; 5% with known CAD). A total of 38 patients (39%) showed normal coronary anatomy, whereas nonsignificant and significant CAD were observed in 37 (38%) and 18 patients (19%), respectively. Importantly, only 4 patients (4%) presented with high-risk CAD using 64-slice MSCT, 2 with left main and 2 with 3-vessel disease. In conclusion, a normal MPI result can be associated with a wide range of anatomic observations and cannot exclude the presence of both nonobstructive and obstructive CAD. However, importantly, the prevalence of high-risk CAD was rare.

Gender influence on the diagnostic accuracy of 64-slice multislice computed tomography coronary angiography for detection of obstructive coronary artery disease

Objective:To compare the diagnostic accuracy of 64-slice multislice computed tomography (MSCT) coronary angiography between female and male patients using conventional coronary angiography as the reference standard.Design:Diagnostic accuracy study.Setting:University hospital.Patients:103 consecutive...

Usefulness of 64-Slice Multislice Computed Tomography Coronary Angiography to Assess In-Stent Restenosis

This study sought to evaluate the diagnostic accuracy of 64-slice multislice computed tomography (MSCT) coronary angiography in the follow-up of patients with previous coronary stent implantation. Recent investigations have shown increased image quality and diagnostic accuracy for noninvasive coronary angiography with 64-slice MSCT as compared with previous-generation MSCT scanners, but data on the evaluation of coronary stents are scarce. In 182 patients (152 [84%] male, ages 58 +/- 11 years) with previous stent (> or =2.5 mm diameter) implantation (n = 192), 64-slice MSCT angiography using either a Sensation 64 (Siemens, Forchheim, Germany) or Aquilion 64 (Toshiba, Otawara, Japan) was performed. At each center, coronary stents were evaluated by 2 experienced observers and evaluated for the presence of significant (> or =50%) in-stent restenosis. Quantitative coronary angiography served as the standard of reference. A total of 14 (7.3%) stented segments were excluded because of poor image quality. In the interpretable stents, 20 of the 178 (11.2%) evaluated stents were significantly diseased, of which 19 were correctly detected by 64-slice MSCT. Accordingly, sensitivity, specificity, and positive and negative predictive value to identify in-stent restenosis in interpretable stents were 95.0% (95% confidence interval [CI] 85% to 100%), 93.0% (95% CI 90% to 97%), 63.3% (95% CI 46% to 81%), and 99.3% (95% CI 98% to 100%), respectively. In-stent restenosis can be evaluated with 64-slice MSCT with good diagnostic accuracy. In particular, a high negative predictive value of 99% was observed, indicating that 64-slice MSCT may be most valuable as a noninvasive method of excluding in-stent restenosis.

Diagnostic Performance of 64-Channel Multislice Computed Tomography in Assessment of Significant Coronary Artery Disease in Symptomatic Subjects

The recent development of 64-channel multislice computed tomography (MSCT) has resulted in noninvasive coronary artery imaging improvement. This study was conducted to determine the accuracy of 64-slice MSCT in a relatively unselected group of 143 patients with presentations suggestive of coronary artery disease, including those with unstable angina pectoris, who underwent both coronary computed tomographic angiography and invasive coronary angiography. No arrhythmia was considered an exclusion criterion except for atrial fibrillation or frequent extrasystoles. In patients with fast heart rates, a beta blocker was administered orally. Data were obtained using electrocardiography gated 64-slice MSCT. Computed tomographic angiography and invasive coronary angiography findings of each coronary segment were compared to determine the sensitivity, specificity, positive predictive value, and negative predictive value of MSCT in the detection of their normalcy or insignificant (<50% diameter decrease) stenosis versus significant (>or=50% diameter decrease) stenosis or total occlusion. In per-patient assessment, the calculated sensitivity, specificity, positive predictive value, and negative predictive value of MSCT were 96%, 67%, 91%, and 83%, respectively. These values in per-artery evaluation were 94%, 94%, 87%, and 97%, and corresponding values in per-segment analysis were 92%, 97%, 77%, and 99%, respectively. In conclusion, computed tomographic angiography has high diagnostic performance in the assessment of significant coronary artery disease in most patients in a daily routine practice, including those presenting with unstable angina pectoris symptoms.

Assessment of global and regional left ventricular function using 64-slice multislice computed tomography and 2D echocardiography: A comparison with cardiac magnetic resonance

Objectives To compare the assessment of global and regional left ventricular (LV) function using 64-slice multislice computed tomography (MSCT), 2D echocardiography (2DE) and cardiac magnetic resonance (CMR). Methods Thirty-two consecutive patients (mean age, 56.5 ± 9.7 years) referred for evaluation of coronary artery using 64-slice MSCT also underwent 2DE and CMR within 48 h. The global left ventricular function which include left ventricular ejection fraction (LVEF), left ventricular end diastolic volume (LVdV) and left ventricular end systolic volume (LVsV) were determine using the three modalities. Regional wall motion (RWM) was assessed visually in all three modalities. The CMR served as the gold standard for the comparison between 64-slice MSCT with CMR and 2DE with CMR. Statistical analysis included Pearson correlation coefficient, Bland-Altman plots and κ-statistics. Results The 64-slice MSCT agreed well with CMR for assessment of LVEF ( r = 0.92; p < 0.0001), LVdV ( r = 0.98; p < 0.0001) and LVsV ( r = 0.98; p < 0.0001). In comparison with 64-slice MSCT, 2DE showed moderate correlation with CMR for the assessment of LVEF ( r = 0.84; p < 0.0001), LVdV ( r = 0.83; p < 0.0001) and LVsV ( r = 0.80; p < 0.0001). However in RWM analysis, 2DE showed better accuracy than 64-slice MSCT (94.3% versus 82.4%) and closer agreement ( κ = 0.89 versus 0.63) with CMR. Conclusion 64-Slice MSCT correlates strongly with CMR in global LV function however in regional LV function 2DE showed better agreement with CMR than 64-slice MSCT.

Accuracy of integration of multislice computed tomography imaging into three-dimensional electroanatomic mapping for real-time guided radiofrequency ablation of left atrial fibrillation—Influence of heart rhythm and radiofrequency lesions

Circumferential radiofrequency ablation around the orifices of the pulmonary veins is a curative catheter-based therapy of paroxysmal and persistent atrial fibrillation (AF). Three-dimensional cardiac image integration is a promising new technology to visualize the complex left atrial anatomy and neighbouring structures. This study aimed to validate the accuracy of integrating multislice computed tomography (MSCT) into three-dimensional electroanatomic mapping (EAM) to guide radiofrequency catheter ablation (CA) of AF. Forty consecutive patients (34 male, mean age 56 +/- 10 years) with multidrug-resistant AF underwent 16-slice MSCT 1 day before radiofrequency CA. MSCT data were processed and imported to the Cartotrade mark EAM system. Using the CartoMergetrade mark Image Integration Module, the generated EAM was aligned with the MSCT images. An integrated statistical algorithm provided information about the accuracy of the fusion process. In every single patient, MSCT images could be aligned with the EAM. Mean distance between the EAM points (n = 63 +/- 14) and the MSCT surface was 1.6 +/- 1.2 mm with no difference between sinus rhythm versus AF (p = 0.145) and no distinction between patients in paroxysmal versus persistent/permanent AF despite a significant difference in left atrial diameters. An average of 388 +/- 81 radiofrequency ablation points were taken within the procedures resulting in a mean distance of 2.3 +/- 1.8 mm between the EAM points and the MSCT image after the ablation procedure. There was a significant difference of alignment accuracy before and after radiofrequency CA (p < 0.001). MSCT images can be accurately integrated into three-dimensional EAM. Pre-interventional cardiac rhythm does not influence the precision of fusion. Accuracy of fusion deteriorates after radiofrequency CA.

Impact of coronary calcium score on diagnostic accuracy of multislice computed tomography coronary angiography for detection of coronary artery disease

The impact of the coronary calcium score on the diagnostic accuracy of multislice computed tomography (MSCT) to detect obstructive coronary stenoses remains controversial. We examined 41 patients (mean Agatston score, 340 +/- 530 [range, 0-2546]) with coronary artery disease with 16-slice MSCT and 60 patients (mean Agatston score, 446 +/- 877 [range, 0-6264]) with 64-slice MSCT. MSCT scans were analyzed with invasive coronary angiography (CA) as the standard of reference. Lesions with luminal narrowing of 50% or greater were considered obstructive. In total, 9% and 2% of uninterpretable segments were excluded from analysis in patients examined with 16- and 64-slice MSCT, respectively. On a segment basis, the percentage of false-negative segments in the groups with Agatston scores of 0 to 100, 101 to 400, and greater than 400 with 16-slice MSCT were 0%, 5.3%, and 2.9% (P = .0005), respectively; other comparisons of false-positive and false-negative segments were not significant. The sensitivity and specificity on a vessel and patient basis with 16- and 64-slice MSCT were not significantly different in different calcium score groups. A slight impact of coronary calcium was observed on the diagnostic accuracy of 16-slice MSCT CA on a segment basis, with no significant impact on a vessel and patient basis. No significant impact of coronary calcium was observed on the diagnostic accuracy of 64-slice MSCT CA on a segment, vessel, or patient basis.

Which patients should be referred for non-invasive angiography with multi-slice CT?

Over the recent years, clinical cardiology has witnessed a rapid evolution of multi-slice computed tomography (MSCT), starting with 4-slice MSCT developing into the current state-of-the-art 64-slice MSCT technology. This technique permits non-invasive visualization of the coronary arteries with high precision. Pooling of 11 studies with 16slice MSCT including 677 patients revealed a sensitivity of 88% to detect significant stenoses on invasive coronary angiography, with a specificity of 96% to rule out significant stenoses [1]. The more recent studies employed 64-slice MSCT and reported sensitivities ranging from 79% to 99% and specificities ranging from 94% to 98%; pooling of the 9 studies (n=542) that performed a head-to-head comparison between 64-slice MSCT and invasive coronary angiography demonstrated a weighted mean sensitivity of 91% and a weighted mean specificity of 96% [2–10]. Based on these excellent results, non-invasive coronary angiography with MSCT has attracted a lot of attention by clinical cardiologists. Based on the high specificity (and the high negative predictive value), rule out of significant (i.e. obstructive) coronary artery disease is possible with MSCT. Accordingly, the general expectancy was that non-invasive angiography would prevent invasive coronary angiography in a substantial number of patients. Indeed, the general experience is that in the presence of normal coronary arteries onMSCT, the likelihood of coronary artery disease is virtually nihil. However, all of the aforementioned studies with 64-slice MSCT [2–10] were performed in patients with a high pre-test likelihood of coronary artery disease, and these patients would have been referred to invasive coronary angiography anyway. The high pre-test likelihood of coronary artery disease in the aforementioned studies is also reflected in the low percentage

Do risk factors influence the diagnostic accuracy of noninvasive coronary angiography with multislice computed tomography?

Multislice computed tomography (MSCT) is a relatively new noninvasive imaging modality in the evaluation of patients with suspected coronary artery disease (CAD). Whether diagnostic accuracy is influenced by gender or risk factors for CAD is currently unknown and was evaluated in this study. In 197 patients (171 men and 26 women; mean age, 60 +/- 11 years) 16-slice MSCT was performed and compared with invasive coronary angiography at 2 different centers (Leiden and Rotterdam, The Netherlands). Diagnostic accuracy for the detection of 50% luminal narrowing or greater was calculated for all patients combined, as well as for patients with known versus suspected CAD. In addition, diagnostic accuracy was determined in men versus women and in different subsets of patients based on the presence of risk factors for CAD including hypertension, type 2 diabetes mellitus, hypercholesterolemia, and obesity. Only segments with a diameter of 2.0 mm or greater were evaluated, whereas smaller segments and stents were excluded from the analysis. Overall, a sensitivity and specificity of 99% and 86%, respectively, on a patient level were demonstrated, with corresponding positive and negative predictive values of 95% and 96%, respectively. Similar values were observed in the different subsets of patients, with no statistical differences. These findings confirm the high diagnostic accuracy of MSCT, regardless of gender or risk factors.