Diagnostic accuracy of 320-row multidetector computed tomography coronary angiography to noninvasively assess in-stent restenosis.

OBJECTIVES: Percutaneous coronary intervention with stent implantation is routinely performed to treat patients with obstructive coronary artery disease. However, thus far, noninvasive assessment of in-stent restenosis has been challenging. Recently, 320-row multidetector computed tomography coronary angiography (CTA) was introduced, allowing volumetric image acquisition of the heart in a single heart beat or gantry rotation. The aim of this study was to evaluate the diagnostic performance of 320-row CTA in the evaluation of significant in-stent restenosis. Invasive coronary angiography (ICA) served as the standard of reference, using a quantitative approach. MATERIALS AND METHODS: The population consisted of patients with previous coronary stent implantation who were clinically referred for cardiac evaluation because of recurrent chest pain and who underwent both CTA and ICA. CTA studies were performed using a 320-row CTA scanner with 320 detector-rows, each 0.5 mm wide, and a gantry rotation time of 350 milliseconds. Tube voltage and current were adapted to body mass index and thoracic anatomy. The entire heart was imaged in a single heart beat, with a maximum of 16-cm craniocaudal coverage. During the scan, the ECG was registered simultaneously for prospective triggering of the data. First, CTA stent image quality was assessed using a 3-point grading scale: (1) good image quality, (2) moderate image quality, and (3) poor image quality. Subsequently, the presence of in-stent restenosis was determined on a stent and patient basis by a blinded observer. Significant in-stent restenosis was defined as >or=50% luminal narrowing in the stent lumen or the presence of significant stent edge stenosis. Overlapping stents were considered to represent a single stent. Results were compared with ICA using quantitative coronary angiography. In addition, CTA stent image quality and diagnostic accuracy were related to stent characteristics and heart rate during CTA image acquisition. RESULTS: The population consisted of 53 patients (37 men, mean age: 65 +/- 13 years) with a total of 89 stents available for evaluation. ICA identified 12 stents (13%) with significant in-stent restenosis. A total of 7 stents (8%) were of nondiagnostic CTA stent image quality, and were considered positive. Sensitivity, specificity, positive, and negative predictive values were 92%, 83%, 46%, and 98%, respectively on a stent basis. Five CTA studies (9%) were of nondiagnostic quality for the evaluation of in-stent restenosis and were considered positive. Sensitivity, specificity, positive, and negative predictive values were 100%, 81%, 58%, and 100%, respectively on a patient level. Stent diameter <3 mm as well as stent strut thickness >or=140 mum were associated with decreased CTA stent image quality and diagnostic accuracy. Heart rate during CTA acquisition and stent overlap were not associated with image degradation. CONCLUSIONS: The present results show that 320-row CTA allows accurate noninvasive assessment of significant in-stent restenosis. However, stents with a large diameter and thin struts allowed better in-stent visualization than stents with a small diameter or thick struts. Consequently, noninvasive assessment of in-stent restenosis using CTA may be an attractive and feasible alternative particularly in carefully selected patients.

Diagnostic accuracy of 320-row multidetector computed tomography coronary angiography in the non-invasive evaluation of significant coronary artery disease.

AIMS: Multidetector computed tomography coronary angiography (CTA) has emerged as a feasible imaging modality for non-invasive assessment of coronary artery disease (CAD). Recently, 320-row CTA systems were introduced, with 16 cm anatomical coverage, allowing image acquisition of the entire heart within a single heart beat. The aim of the present study was to assess the diagnostic accuracy of 320-row CTA in patients with known or suspected CAD. METHODS AND RESULTS: A total of 64 patients (34 male, mean age 61 +/- 16 years) underwent CTA and invasive coronary angiography. All CTA scans were evaluated for the presence of obstructive coronary stenosis by a blinded expert, and results were compared with quantitative coronary angiography. Four patients were excluded from initial analysis due to non-diagnostic image quality. Sensitivity, specificity, and positive and negative predictive values to detect > or =50% luminal narrowing on a patient basis were 100, 88, 92, and 100%, respectively. Moreover, sensitivity, specificity, and positive and negative predictive values to detect > or =70% luminal narrowing on a patient basis were 94, 95, 88, and 98%, respectively. With inclusion of non-diagnostic imaging studies, sensitivity, specificity, and positive and negative predictive values to detect > or =50% luminal narrowing on a patient basis were 100, 81, 88, and 100%, respectively. CONCLUSION: The current study shows that 320-row CTA allows accurate non-invasive assessment of significant CAD.

Type 2 diabetes is associated with more advanced coronary atherosclerosis on multislice computed tomography and virtual histology intravascular ultrasound.

BACKGROUND: Data on coronary plaque observations on multi-slice computed tomography (MSCT) in patients with type 2 diabetes are scarce. METHODS AND RESULTS: In total, 60 patients (19 with diabetes) underwent 64-slice MSCT, followed by conventional coronary angiography with intravascular ultrasound (IVUS). Non-invasively, the extent of coronary atherosclerosis and 3 plaque types (non-calcified, calcified, mixed) were visually evaluated on MSCT. Invasively, plaque burden was assessed on gray-scale IVUS. Plaque composition was evaluated on virtual histology intravascular ultrasound (VH IVUS). Concerning geometrical plaque data, diabetic patients showed more plaques on MSCT (7.1 +/- 3.2 vs 4.9 +/- 3.2 in non-diabetic patients, P = .01). On gray-scale IVUS, diabetes was associated with a larger plaque burden (48.7 +/- 10.7% vs 40.0 +/- 12.1%, P = .003). Concerning plaque composition, diabetes was associated with more calcified plaques on MSCT (52% vs 24%). Relatively more fibrocalcific plaques in diabetic patients (29% versus 9%) were observed on VH IVUS. Moreover, these plaques contained more necrotic core (10.8 +/- 5.9% vs 8.6 +/- 5.2%, P = .01). CONCLUSION: A higher plaque extent and more calcified lesions were observed in diabetic patients on MSCT. The findings were confirmed on gray-scale and VH IVUS. Thus, MSCT may potentially be used to explore patterns of coronary atherosclerosis in diabetic patients.

Comparison between tissue Doppler imaging and velocity-encoded magnetic resonance imaging for measurement of myocardial velocities, assessment of left ventricular dyssynchrony, and estimation of left ventricular filling pressures in patients with ischemic cardiomyopathy.

Velocity-encoded magnetic resonance imaging (VE-MRI), commonly used to perform flow measurements, can be applied for myocardial velocity analysis, similar to tissue Doppler imaging (TDI). In this study, a comparison between VE-MRI and TDI was performed for the assessment of left ventricular dyssynchrony and left ventricular filling pressures. Ten healthy volunteers and 22 patients with heart failure secondary to ischemic cardiomyopathy underwent both VE-MRI and TDI. Longitudinal myocardial peak systolic and diastolic velocities and time to peak systolic velocity (Ts) were measured with both techniques at the level of left ventricular septum and lateral wall. To quantify left ventricular dyssynchrony, the delay in Ts between basal septum and lateral wall was calculated (SLD) and patients were categorized into 3 groups: minimal (SLD <30 ms), intermediate (SLD = 30 to 60 ms) and extensive (SLD >60 ms) left ventricular dyssynchrony. The ratio of transmitral E wave velocity and mitral annulus septal early velocity (E/E' ratio) was also assessed, and patients were divided into 3 groups: normal (E/E' <8), probably abnormal (E/E' = 8 to 15), and elevated (E/E' >15) left ventricular filling pressures. Excellent correlations were observed for peak systolic velocity and peak diastolic velocity (r = 0.95, p <0.001) measured with TDI and VE-MRI. A small bias (p <0.001) of -1.1 +/- 1.1 cm/s for peak systolic velocity and of -0.45 +/- 1.03 cm/s for peak diastolic velocity was noted between the 2 techniques. A strong correlation was also noted between Ts measured with TDI and VE-MRI (r = 0.97, p <0.001) without a significant difference. TDI and VE-MRI showed an excellent agreement for left ventricular dyssynchrony and left ventricular filling pressures classification with a weighted kappa of 0.96 and 0.91, respectively. In conclusion, TDI and VE-MRI are highly concordant and can be used interchangeably for the assessment of left ventricular dyssynchrony and filling pressures.

Head-to-head comparison of coronary plaque evaluation between multislice computed tomography and intravascular ultrasound radiofrequency data analysis.

OBJECTIVES: 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). BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Invasive versus noninvasive evaluation of coronary artery disease.

OBJECTIVES: We sought to compare the diagnostic information obtained from noninvasive characterization of coronary artery disease by using multidetector computed tomography (MDCT) and myocardial perfusion imaging (MPI) and to compare findings with the use of invasive coronary angiography and intravascular ultrasound (IVUS). BACKGROUND: Preliminary comparisons have suggested that abnormal myocardial perfusion studies correlate well with significant luminal stenosis on MDCT coronary angiography. However, atherosclerotic coronary lesions may be detectable with the use of MDCT even in the presence of normal myocardial perfusion METHODS: We performed MDCT, MPI, and conventional coronary angiography in 70 patients. In addition, IVUS was performed in 53 patients. Quantitative information was obtained from quantitative coronary angiography (QCA) and IVUS assessment of plaque burden and minimal luminal area. RESULTS: Of 26 patients with an abnormal MPI study, 23 (88%) showed significant stenosis on MDCT. As compared with QCA, MDCT showed a sensitivity of 96% and specificity of 67% for the detection of stenoses > or =50% diameter narrowing in these patients. Mean diameter stenosis on QCA was 76% and mean minimal lumen area in IVUS was 3.3 mm(2). On the other hand, 27 (84%) of 44 patients with normal MPI had evidence of coronary atherosclerosis on MDCT (luminal stenosis > or =50%: n = 15, luminal stenosis <50%: n = 12, sensitivity of 100% and specificity of 83% as compared with QCA). Using IVUS, we found substantial plaque burden (mean 58.9 +/- 18.1% of cross-sectional area), but presence of a stenosis (minimal lumen area <4.0 mm(2)) in only 14 patients (mean minimal lumen area, 5.8 +/- 3.3 mm(2)). Only 7 patients with normal myocardial perfusion scans demonstrated absence of coronary atherosclerosis by MDCT. CONCLUSIONS: Considerable plaque burden can be observed with MDCT even in the absence of myocardial perfusion abnormalities. This finding does not constitute a false-positive MDCT result, but rather reflects the fact that MDCT can detect atherosclerotic lesions that are not flow-limiting.

Evaluation of patients with previous coronary stent implantation with 64-section CT.

PURPOSE: To prospectively evaluate the diagnostic accuracy of 64-section computed tomography (CT) for the assessment of in-stent or peristent restenosis, with conventional coronary angiography as the reference standard. MATERIALS AND METHODS: The study was approved by the medical ethics committee, and informed consent was obtained in all 50 enrolled patients (40 men, 10 women; mean age, 60 years +/- 11 [standard deviation]). In addition to conventional coronary angiography with quantitative coronary angiography, 64-section CT was performed. For each stent, assessability was determined and was related to stent characteristics and heart rate by using a chi(2) test. On the interpretable images of stents and peristent lumina (5.00 mm proximal and distal to the stent), the presence of significant (> or =50%) restenosis was determined. For this analysis, partially overlapping stents were considered to represent a single stent. RESULTS: Of 76 stents, 65 (86%) were determined to be assessable. Increased heart rate and overlapping positioning were associated with increased uninterpretability of the images of stents (P < .05), whereas location of the stent and thickness of the strut were not. In seven patients, stents were placed in an overlapping manner, resulting in 58 stents available for the evaluation of significant (> or =50%) in-stent restenosis. All six significant (> or =50%) in-stent restenoses were detected, and the absence of significant (> or =50%) restenosis was correctly identified in the 52 remaining stents, resulting in sensitivity and specificity of 100%. Sensitivity and specificity for the detection of significant (> or =50%) peristent stenosis were 100% and 98%, respectively. CONCLUSION: In selected patients with previous stent implantation, 64-section CT can be used to evaluate in-stent restenosis with high accuracy. Accordingly, the technique may be useful for noninvasive exclusion of in-stent or peristent restenosis, thereby avoiding invasive imaging in a considerable number of patients.