多层螺旋CT冠状动脉成像的护理体会

冠心病 (CHD)是严重危害人类健康的常见病 ,多层螺旋CT以扫描速度快 ,空间分辨率高的优势 ,用于早期冠状动脉疾病的诊断有重要意义。我院自 2 0 0 3年 11月～ 2 0 0 4年 6月对 6 5例临床诊断或可疑冠心病的患者行多层螺旋CT冠状动脉造影 (multi slicespiralCTcoronaryangiography ,MSSCTCA)均取得满意的结果。现将此项检查的护理体会报告如下。1　材料与方法　　我院 2 0 0 3年 11月～ 2 0 0 4年 6月对 6 5例 ,其中男 5 3例 ,女 12例 ,年龄 37～ 76岁 ,平均年龄 5 7岁。使用GElightspeed 16层螺旋CT进行扫描及AWOZ工作站进行图像…     

Image quality of noninvasive coronary angiography using multislice spiral computed tomography and electron-beam computed tomography: intraindividual comparison in an animal model

OBJECTIVE: Comparison of coronary artery visualization by multislice spiral CT (MSCT) and electron-beam CT (EBCT). MATERIALS AND METHODS: Six minipigs underwent MSCT (collimation 4 x 1 mm, gantry rotation time 500 milliseconds, acquisition time per cardiac cycle 126 +/- 30 milliseconds) and EBCT (slice thickness 1.5 mm, acquisition time per scan 100 milliseconds). Visualized vessel length and contour sharpness was measured, contrast-to-noise ratios were calculated, and the frequency of motion artifacts were evaluated. RESULTS: MSCT depicted significantly longer segments of the coronary tree than EBCT (length: 248.8 vs. 222.8 mm; P < 0.05), delineated the vessel contours more sharply (slope of density curves: 219.2 vs. 160.2 DeltaHU/mm; P < 0.05), and had a higher contrast-to-noise ratio (13.4 vs. 7.3; P < 0.05). The frequency of motion artifacts did not differ between both modalities (94.7% vs. 95.7% of visualized vessel length; P > 0.05). CONCLUSIONS: Because its higher spatial resolution and lower image noise, MSCT seems to be superior to EBCT in the visualization of the coronary arteries. Despite different temporal resolutions motion artifacts seem to be similar with both modalities.     

Influence of intracoronary attenuation on coronary plaque measurements using multislice computed tomography: observations in an ex vivo model of coronary computed tomography angiography

Assessment of attenuation (measured in Hounsfield units, HU) of human coronary plaques was performed using multislice computed tomography (MSCT) in an ex vivo model. In three ex vivo specimens of left coronary arteries in oil, MSCT was performed after intracoronary injection of four solutions of contrast material (400 mgI/ml iomeprol). The four solutions were diluted as follows: 1/, 1/200, 1/80, and 1/20. All scans were performed with the following parameters: slices/collimation 16/0.75 mm, rotation time 375 ms. Each specimen was scored for the presence of atherosclerotic plaques. In each plaque the attenuation was measured in four regions of interest for lumen, plaque (non-calcified thickening of the vessel wall), calcium, and surrounding (oil surrounding the vessel). The results were compared with a one-way analysis of variance test and were correlated with Pearsons test. There were no significant differences in the attenuation of calcium and oil in the four solutions. The mean attenuation in the four solutions for lumen (35±10, 91±7, 246±18, 511±89 HU) and plaque (22±22, 50±26, 107±36, 152±67 HU) was significantly different between each decreasing dilution (p<0.001). The mean attenuation of lumen and plaque of coronary plaques showed high correlation, while the values were significantly different (r=0.73; p<0.001). Intracoronary attenuation modifies significantly the attenuation of plaques assessed with MSCT.     

New approach to noninvasive coronary angiography by multidetector computed tomography: initial experience using gadolinium

OBJECTIVE: To investigate the gadolinium performance for 16-detector-row coronary computed tomography (CT) angiography. METHODS: Ethics committee approval and informed consent were obtained. Ten patients with coronary artery disease underwent digital coronary angiography and gadolinium-enhanced CT coronary angiography (Gd-CTCA) within the same week. For the Gd-CTCA, each patient received a dose of 0.3 mmol/kg of body weight of 0.5 mmol/mL gadoterate meglumine. Two readers interpreted the CT angiographies independently, and their results were matched with the digital angiography findings. The diagnostic accuracy of Gd-CTCA was calculated by the exact binomial method. RESULTS: Sensitivity, specificity, and positive and negative predictive values were for observer 1: 91.67%, 98.73%, 84.62%, and 99.36%, and for observer 2: 83.33%, 98.73%, 83.33%, and 98.73%, respectively. CONCLUSION: Preliminary results demonstrated that gadolinium chelates may be used as an alternative CT contrast media in coronary CT angiographies, without detriment to diagnosis results.     

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

Background  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. Methods and Results  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. Conclusion  These findings confirm the high diagnostic accuracy of MSCT, regardless of gender or risk factors. This work was financially supported by The Netherlands Heart Foundation, The Hague, The Netherlands (grants 2002B105 and 2001D032).     

Impact of intravascular enhancement, heart rate, and calcium score on diagnostic accuracy in multislice computed tomography coronary angiography

PURPOSE: To assess the effect of intravascular enhancement, heart rate, and calcium score on diagnostic accuracy in the detection of significant coronary artery stenosis using 16-row multislice computed tomography (MSCT). MATERIALS AND METHODS: One hundred patients (88 males; 59+/-11 years) with suspected coronary artery disease who had undergone conventional coronary angiography (CA) and MSCT-CA were retrospectively enrolled for the study. Patients underwent a MSCT-CA, with the following protocol: collimation 16x0.75 mm, gantry rotation time 420 ms, feed/rotation 2.8 mm, kV 120, mAs 400-500. The protocol for contrast material administration was 100 ml of Iodixanol 320 mgI/ml at 4 ml/s and the scan delay was defined with a bolus tracking technique. In all patients vascular enhancement was measured in the aortic root, and in the left and right coronary arteries. The average vascular enhancement was used to divide the population in two groups of 50 patients each, one with lower enhancement (Low), and one with higher enhancement (High). In the two groups diagnostic accuracy (per coronary segment) for the detection of significant stenosis (= or >50% lumen reduction) was evaluated in vessels = or >2 mm in diameter using quantitative CA as the reference standard. The differences in diagnostic accuracy were compared with a Chi-square test and a p<0.05 was considered significant. RESULTS: Of the total 1116 segments (= or >2 mm lumen diameter), 173 presented significant stenosis. The sensitivity and specificity for the assessment of significant stenosis were 89.4% and 93.3% vs 94.3% and 97.4% in the presence of increasing intravascular enhancement, 92.8% and 96.7% vs 91.1% and 93.9% in the presence of increasing heart rate, and 89.7% and 97.6% vs 93.3% and 92,8% in the presence of an increasing calcium score. CONCLUSIONS: Increasing intravascular enhancement significantly improves diagnostic accuracy in MSCT-CA. A higher heart rate lowers the specificity in the detection of significant obstructing lesions of the coronary artery. An increasing calcium score determines a lower specificity and a higher sensitivity.     

High iodine concentration contrast material for noninvasive multislice computed tomography coronary angiography: iopromide 370 versus iomeprol 400

OBJECTIVE: The objective of this study was to compare intracoronary attenuation on 16-row multislice computed tomography (16-MSCT) coronary angiography using 2 contrast materials (CM) with high iodine concentration. MATERIAL AND METHODS: Forty consecutive patients (29 male, 11 female; mean age, 61+/-11 years) with suspected coronary artery disease were randomized to 2 groups to receive 100 mL of either iopromide 370 (group 1: Ultravist 370, 370 mg iodine/mL; Schering AG, Berlin, Germany) or iomeprol 400 (group 2: Iomeron 400, 400 mg iodine/mL; Bracco Imaging SpA, Milan, Italy). Both CM were administered at a rate of 4 mL/s. All patients underwent 16-MSCT coronary angiography (Sensation 16; Siemens, Germany) with collimation 16 x 0.75 mm and rotation time 375 ms. The attenuation in Hounsfield units (HU) achieved after each CM was determined at regions of interest (ROIs) placed at the origin of coronary arteries and on the ascending aorta, descending aorta, and pulmonary artery. Differences in mean attenuation in the coronary arteries and on the ascending aorta, descending aorta, and pulmonary artery were evaluated using Student t test. RESULTS: The mean attenuation achieved at each anatomic site was consistently greater after iomeprol 400 than after iopromide 370. At the origin of coronary arteries, the mean attenuation after iomeprol 400 (340+/-53 HU) was greater (P<0.05) than that after iopromide 370 (313+/- 42 HU). Similar findings were noted for the mean attenuation in the ascending aorta, descending aorta, and pulmonary artery. CONCLUSION: The intravenous administration of iomeprol 400 provides higher attenuation of the coronary arteries and of the great arteries of the thorax as compared with iopromide 370 using the same injection parameters.     

Evaluation of computed tomography coronary angiography in patients with a high heart rate using 16-slice spiral computed tomography with 0.37-s gantry rotation time

The aim of our study is to evaluate computed tomography (CT) coronary angiography in patients with a high heart rate using 16-slice spiral CT with 0.37-s gantry rotation time. We compare the image quality of patients whose heart rates were over 70 beats per minute (bpm) with that of patients whose heart rates were 70 bpm or less. Sixty patients with various heart rates underwent retrospectively ECG-gated multislice spiral CT (MSCT) coronary angiography. Two experienced observers who were blind to the heart rates of the patients evaluated all the MSCT coronary angiographic images and calculated the assessable segments. A total of 620 out of 891 (69.6%) segments were satisfactorily visualized. On average, 10.3 coronary artery segments per patient could be evaluated. In 36 patients whose heart rates were below 70 bpm [mean 62.2 bpm±5.32 (standard deviation, SD)], the number of assessable segments was 10.72±2.02 (SD). In the other 24 patients whose heart rates were above 70 bpm [mean 78.6 bpm±8.24 (SD)], the corresponding number was 9.75±1.74 (SD). No statistically significant difference was found in these two subgroups t test, P>0.05. The new generation of 16-slice spiral CT with 0.37-s rotation time can satisfactorily evaluate the coronary arteries of patients with high heart rates (above 70 bpm, up to 102 bpm).     

Acceptance of noninvasive computed tomography coronary angiography: for a patient-friendly medicine

Purpose

This study was done to evaluate the psychological state and anxiety of patients undergoing computed tomography coronary angiography (CTCA), and assess their acceptance and satisfaction compared to invasive conventional coronary angiography (CCA).

Materials and methods

A total of 442 consecutive patients (282 male; mean age 57.7 ± 9.5 years) who underwent CTCA for suspected or known coronary artery disease were evaluated with the Endler Multimodality Anxiety Scales (EMAS) before and after the scan, and a questionnaire administered after the scan. Among the 442 patients, 181 had a history of CCA. Two radiologists assessed the image quality of CTCA.

Results

Anxiety was more intense prior to the scan (EMAS score 51.7 vs. 46.7, p < 0.01) and in patients with a history of CCA (EMAS score 55.5 vs. 49.1, p < 0.01). Women presented more intense anxiety (EMAS score 59.5 vs. 47.3, p < 0.01), higher mean heart rate (63.5 ± 7.6 vs. 60.7 ± 7.3 beats per minute, p < 0.01) and a lower image quality than men (p < 0.0001). CTCA proved to be more acceptable than CCA because of accurate preparation, lower concern prior to the examination, negligible pain, higher comfort, and greater overall satisfaction (p < 0.0001).

Conclusions

Computed tomography coronary angiography is a patient-friendly imaging method because of the minimal perceived discomfort. Anxiety may affect CTCA image quality in women.     

Triage of patients with suspected coronary artery disease using multislice computed tomography

RATIONALE AND OBJECTIVES: Several studies have shown that multislice computed tomography (MSCT) has a high sensitivity and specificity for detecting coronary artery stenoses. The aim of the present study was to investigate whether MSCT can reliably triage patients with suspected coronary artery disease (CAD) to coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or no revascularization. MATERIALS AND METHODS: A total of 123 patients with suspected CAD who were referred for conventional coronary angiography (CATH) additionally underwent MSCT (16*0.5 mm detector collimation). Therapeutic decisions made on the basis of CATH and MSCT strictly following current guidelines for treatment of CAD were compared with decisions made by a cardiac surgeon and an interventional cardiologist. Only MSCTs with at least adequate image quality in all coronary segments were included in the analysis (94/123). RESULTS: Decisions made on the basis of MSCT and CATH according to guidelines did not differ significantly (agreement of 88%, 82 of 94, P = .319). The therapeutic decisions made by the interventional cardiologist and the cardiac surgeon based on CATH differed significantly (overall agreement of 79%, 74 of 94 cases, P < .001; cardiologist: 78% PCI and 22% CABG versus surgeon: 38% PCI and 62% CABG), whereas there was 100% agreement regarding decisions for or against invasive treatment. CONCLUSIONS: MSCT shows good agreement with CATH in triaging patients with suspected CAD to CABG, PCI, or no revascularization. The choice of revascularization procedure is significantly more strongly influenced by whether an interventional cardiologist or a cardiac surgeon makes the decision than by the diagnostic test on which the decision is based.     

Assessment of coronary stent in vitro on multislice computed tomography angiography: improved in-stent visibility by the use of 140-kV tube voltage

OBJECTIVE: To assess the effect of tube voltage on the in-stent visibility of coronary stents in vitro on computed tomography (CT) angiography. METHODS: A total of 6 vascular models (3 models without stenosis and 3 with stenosis) using 3 kinds of stent (Bx Velocity, Express2, and Driver) with an inner diameter of approximately 3.5 mm and filled with contrast material (CT attenuation, 450 Hounsfield units) were scanned by means of a 16-detector row CT. We assessed the visual stenosis evaluation and inhomogeneity of stent lumen in 4 orientations (0-, 30-, 60-, and 90-degree angles) relative to the z-axis of the scanner using 3 imaging techniques (120-kV tube voltage using a medium convolution kernel, 120-kV tube voltage using a convolution kernel for bone, and 140-kV tube voltage using a convolution kernel for bone). Statistical analysis involved F test with a statistical significance of P < 0.05. RESULTS: The convolution kernel for bone made it easier to evaluate the stenosis inside the stents, although it increased the luminal inhomogeneity significantly (Bx Velocity and Express2, P < 0.005; Driver, P < 0.05). The luminal inhomogeneity tended to increase as the strut diameter and the weight per unit length increased. Using 120-kV tube voltage, the luminal inhomogeneity inside the stents was at the minimum in the angle of 0 degree relative to the z-axis, and at the maximum in the angle of 90 degrees, except for Driver. The 140-kV tube voltage was effective for the improvement of luminal inhomogeneity and visibility of in-stent stenosis compared with the 120-kV tube voltage. CONCLUSIONS: The in-stent visibility of coronary stents on CT angiography can be improved by the use of 140-kV tube voltage with the convolution kernel for bone.     

Diagnostic value of multislice computed tomography angiography in coronary artery disease: a meta-analysis

PURPOSE: To perform a meta-analysis of the diagnostic value of multislice CT (MSCT) angiography in the detection of coronary artery disease (CAD) when compared to conventional coronary angiography. MATERIALS AND METHODS: A search of PubMed and MEDLINE databases for English literature was performed. Only studies with at least 10 patients comparing MSCT angiography with conventional coronary angiography in the detection of CAD were included. Diagnostic value of MSCT angiography compared to coronary angiography was compared and analyzed at segment-, vessel- and patient-based assessment. RESULTS: 47 studies (67 comparisons) met the criteria and were included in our study. Pooled overall sensitivity, specificity and 95% confidence interval for MSCT angiography in the detection of CAD were 83% (79%, 89%), 93% (91%, 96%) at segment-based analysis; 90% (87%, 94%), 87% (80%, 93%) at vessel-based analysis; and 91% (88%, 95%), 86% (81%, 92%) at patient-based analysis, respectively. Diagnostic accuracy of MSCT angiography in evaluating assessable segments was significantly improved with 64-slice scanners when compared to that with 4- and 16-slice scanners (p<0.05). CONCLUSION: Our meta-analysis showed that MSCT angiography has potential diagnostic accuracy in the detection of CAD. Diagnostic performance of MSCT angiography has been significantly improved with the latest 64-slice CT, with resultant high qualitative and quantitative diagnostic accuracy. 16-slice CT was limited in spatial resolution which makes it difficult to perform quantitative assessment of coronary artery stenoses.     

Influence of convolution filtering on coronary plaque attenuation values: observations in an ex vivo model of multislice computed tomography coronary angiography

Attenuation variability (measured in Hounsfield Units, HU) of human coronary plaques using multislice computed tomography (MSCT) was evaluated in an ex vivo model with increasing convolution kernels. MSCT was performed in seven ex vivo left coronary arteries sunk into oil followingthe instillation of saline (1/∞) and a 1/50 solution of contrast material (400 mgI/ml iomeprol). Scan parameters were: slices/collimation, 16/0.75 mm; rotation time, 375 ms. Four convolution kernels were used: b30f-smooth, b36f-medium smooth, b46f-medium and b60f-sharp. An experienced radiologist scored for the presence of plaques and measured the attenuation in lumen, calcified and noncalcified plaques and the surrounding oil. The results were compared by the ANOVA test and correlated with Pearson’s test. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The mean attenuation values were significantly different between the four filters (p < 0.0001) in each structure with both solutions. After clustering for the filter, all of the noncalcified plaque values (20.8 ± 39.1, 14.2 ± 35.8, 14.0 ± 32.0, 3.2 ± 32.4 HU with saline; 74.7 ± 66.6, 68.2 ± 63.3, 66.3 ± 66.5, 48.5 ± 60.0 HU in contrast solution) were significantly different, with the exception of the pair b36f–b46f, for which a moderate-high correlation was generally found. Improved SNRs and CNRs were achieved by b30f and b46f. The use of different convolution filters significantly modifief the attenuation values, while sharper filtering increased the calcified plaque attenuation and reduced the noncalcified plaque attenuation.