Noninvasive coronary artery imaging by multislice spiral computed tomography

Localization of the sinoatrial and atrioventricular nodal region in neonatal and juvenile ovine hearts

Localization of the components of the cardiac conduction system (CCS) is essential for many therapeutic procedures in cardiac surgery and interventional cardiology. While histological studies provided fundamental insights into CCS localization, this information is incomplete and difficult to translate to aid in intraprocedural localization. To advance our understanding of CCS localization, we set out to establish a framework for quantifying nodal region morphology. Using this framework, we quantitatively analyzed the sinoatrial node (SAN) and atrioventricular node (AVN) in ovine with postmenstrual age ranging from 4.4 to 58.3 months. In particular, we studied the SAN and AVN in relation to the epicardial and endocardial surfaces, respectively. Using anatomical landmarks, we excised the nodes and adjacent tissues, sectioned those at a thickness of 4 μm at 100 μm intervals, and applied Masson's trichrome stain to the sections. These sections were then imaged, segmented to identify nodal tissue, and analyzed to quantify nodal depth and superficial tissue composition. The minimal SAN depth ranged between 20 and 926 μm. AVN minimal depth ranged between 59 and 1192 μm in the AVN extension region, 49 and 980 μm for the compact node, and 148 and 888 μm for the transition to His Bundle region. Using a logarithmic regression model, we found that minimal depth increased logarithmically with age for the AVN (R2 = 0.818, P = 0.002). Also, the myocardial overlay of the AVN was heterogeneous within different regions and decreased with increasing age. Age associated alterations of SAN minimal depth were insignificant. Our study presents examples of characteristic tissue patterns superficial to the AVN and within the SAN. We suggest that the presented framework provides quantitative information for CCS localization. Our studies indicate that procedural methods and localization approaches in regions near the AVN should account for the age of patients in cardiac surgery and interventional cardiology.

Noninvasive Tissue Characterization of Coronary Arterial Plaque by 16-Slice Computed Tomography in Acute Coronary Syndrome

Noninvasive characterization of coronary plaques is challenging for cardiologists. The authors’ goal was to explore the clinical feasibility of newly developed 16-slice computed tomography (CT) in tissue characterization of coronary arterial plaques in patients with acute coronary syndrome. Sixteen patients with acute coronary syndrome underwent 16-slice CT (Aquillion, Toshiba) and coronary arteriography with intravascular ultrasound (IVUS) within 7 days. Twenty-three plaques were classified by IVUS according to plaque echogenicity: 6 soft plaques, 11 intermediate plaques, and 6 calcified plaques. Mean (±SD) CT numbers (Hounsfield units [HU]) of these 3 types of plaques were 50.6 ±14.8 HU, 131 ±21.0 HU, and 721 ±231 HU, respectively. Sixteen-slice CT facilitates noninvasive tissue characterization of coronary arterial plaques.

A preliminary study of the potential role of FGF-23 in coronary calcification in patients with suspected coronary artery disease

OBJECTIVE

The association of fibroblast growth factor 23 (FGF-23) with vascular disease in patients with preserved renal function is not well understood. The purpose of this study was to investigate the relationship of serum FGF-23 with coronary calcification in patients without chronic kidney disease and diabetes mellitus (DM).

METHODS

A cross-sectional study was performed in 148 consecutive patients with suspected coronary artery disease who underwent 64-slice computed tomography coronary angiography for diagnosis of coronary artery disease. Patients with eGFR <60 mL/min/1.73 m(2), proteinuria, or DM were excluded. Associations of coronary calcification (evaluated by Agatston score) were examined with classical risk factors and with inflammatory markers, adipocytokines and FGF-23.

RESULTS

The median creatinine, eGFR and FGF-23 levels were 0.7 mg/dL, 74.6 mL/min/1.73 m(2), and 26 pg/mL respectively. The strongest association was found between age and Agatston score (r = 0.367, p < 0.001) in univariate logistic regression analysis. No atherogenic risk factors, including inflammatory markers and adipocytokine levels, were associated with Agatston score. Among calcium/phosphate metabolism markers, FGF-23 showed a weak but significant correlation with Agatston score (r = 0.169, p = 0.039). In multivariate linear regression analysis, age and FGF-23 (r = 0.188, p = 0.016) were independently associated with the Agatston score.

CONCLUSION

Serum FGF-23 levels were associated with coronary calcification independently of classical risk factors and of adipocytokines and inflammatory markers in patients with preserved renal function. FGF-23 may also have a direct effect on progression of coronary calcification and further studies are required to examine this issue.

Non-invasive assessment and clinical strategy of stable coronary artery disease by magnetic resonance imaging, multislice computed tomography and myocardial perfusion SPECT

Coronary multislice computed tomography (MSCT) angiography and magnetic resonance angiography (MRA) have emerged as new diagnostic techniques that allow direct visualization of the coronary artery. These new modalities have both advantages and disadvantages concerning radiation exposure, the use of contrast medium, ability of visualizing heavily calcified artery lumens, and spatial and temporal resolution. However, these modalities only provide anatomical information of the coronary artery. Functional assessment of the severity of coronary artery disease (CAD) is essential for the management of patients with known or suspected CAD in practical clinical settings. Myocardial perfusion single-photon emission computed tomography is thought to be the most suitable diagnostic procedure for the determination of therapeutic strategy when coronary MSCT and MRA show significant and also insignificant coronary artery lesions. (Circ J 2010; 74: 34 - 40).

Detection of coronary artery disease by free-breathing, whole heart coronary magnetic resonance angiography: our initial experience

Free-breathing, whole heart coronary magnetic resonance angiography (MRA) has gained great attention as a totally noninvasive diagnostic modality for the detection of coronary artery disease. We examined the accuracy of coronary MRA to identify the presence or absence of coronary artery stenosis in comparison with conventional coronary angiography. Free-breathing, whole heart coronary MRA was performed in 43 consecutive patients undergoing conventional coronary angiography. A total of 172 coronary arteries and 344 coronary artery segments were analyzed. In the coronary artery segment-based analysis, the sensitivity to detect coronary stenosis >/=50% was 82% and specificity was 100%. The accuracy, positive predictive value, and negative predictive value was 97%, 98%, and 96%, respectively. In the vessel-based analysis the sensitivity was 86%, specificity 99%, accuracy 95%, positive predictive value 98%, and negative predictive value 94%. In the patient-based analysis, the sensitivity to detect coronary stenosis <50% was 97% and the specificity to define luminal narrowing <50% was 90%. The accuracy, positive predictive value, and negative predictive value was 95%, 97%, and 90%, respectively. Free-breathing, whole heart coronary MRA yields excellent diagnostic accuracy to detect significant coronary artery disease and has the potential to become the routine diagnostic modality for patients with suspected coronary artery disease.

Evaluation of vulnerable coronary plaques and non-alcoholic fatty liver disease (NAFLD) by 64-detector multislice computed tomography (MSCT)

BACKGROUND

Multislice computed tomography (MSCT) permits direct visualization of not only coronary artery stenosis but also the characteristics of plaques in patients with coronary artery disease (CAD). Also, because of its potential to be a novel risk factor for cardiovascular disease, interest in non-alcoholic fatty liver disease (NAFLD) is increasing.

METHODS AND RESULTS

Participants comprised 298 consecutive patients who received MSCT to diagnose CAD. Patients with an alcohol intake exceeding 20 g/day or with a history of known liver disease were excluded from the study. Liver steatosis and 4 coronary artery findings, including remodeling lesions, lipid core plaques, calcified plaques and narrowing of lumen, were assessed. Liver steatosis was evaluated by computed tomography density of the liver and spleen. In the study, NAFLD was defined as having a liver and spleen (L:S) ratio of <1.1. The L:S ratios of patients with remodeling lesions or lipid core plaques were significantly lower than those without. NAFLD was related significantly to those findings, but there was no correlation between calcified plaques, narrowing of lumen and L:S ratios. Adjusted odds ratio of NAFLD for remodeling lesions was 2.41 (95% confidence interval (CI), 1.24-4.67; p=0.009), and those for lipid core lesions was 2.29 (95% CI, 1.15-4.56; p=0.018).

CONCLUSION

NAFLD is a novel risk factor for vulnerable plaques.

Anomalous coronary arteries in adults detected by multislice computed tomography: presentation of cases from multicenter registry and review of the literature

Anomalous coronary arteries are a rare condition, but they may cause myocardial ischemia, heart failure, and sudden death. We evaluated the prevalence and multislice computed tomographic (MSCT) findings of anomalous coronary arteries in a large number of patients from the multicenter registry. At four institutes, 29 (0.74%) out of 3910 patients were found to have anomalous coronary arteries by MSCT. They consisted of 15 patients with anomalous origins of the right coronary artery, 1 with right-sided origin of the left circumflex artery, 1 with right-sided origin of the left main coronary artery, 2 with double right coronary arteries, 2 with the absence of the left circumflex artery, 1 with absence of the right coronary artery, 6 with coronary artery fistulas, and 1 with Bland-White-Garland syndrome. Multislice computed tomography findings were consistent with those obtained by conventional coronary angiography in all 14 patients undergoing both diagnostic procedures. Multislice computed tomography permits three-dimensional comprehension of coronary arteries, which is suitable for the diagnosis of anomalous coronary arteries.

Prognostic value of non-obstructive CT low-dense coronary artery plaques detected by multislice computed tomography

BACKGROUND

The prognostic value of non-obstructive, CT low-dense plaques (CTLDP) on multislice computed tomography (MSCT) for the prediction of nonfatal acute myocardial infarction (AMI), unstable angina (UA) and cardiac death has not yet been defined.

METHODS AND RESULTS

In the present study 810 patients who underwent MSCT and had non-obstructive coronary artery disease were followed up for the occurrence of AMI, UA and cardiac death. Non-obstructive CTLDP were defined as plaques with a CT density <68 Hounsfield units, accompanied by mild to moderate coronary artery stenosis (25-75%). Patients were followed-up for 1,062+/-544 days for the occurrence of (1) acute coronary syndrome (ACS) including nonfatal AMI and UA, and (2) cardiac death. CTLDP were detected in 189 patients (23.3%). The annual event rate of AMI, UA, ACS and cardiac death was 0.91%, 0.91%, 1.82% and 0.36%, respectively, in patients with CTLDP and 0.10%, 0.55%, 0.66% and 0.21%, respectively, in patients without CTLDP. The event rate of ACS was significantly higher in patients with CTLDP than in those without CTLDP (p<0.001). Multivariate Cox proportional regression analysis revealed that previous MI and the presence of CTLDP were independent predictors of ACS.

CONCLUSION

Non-obstructive CTLDP detected by MSCT yield prognostic information toward the identification of ACS.

Coronary artery dissection after blunt chest trauma: Depiction at multidetector-row computed tomography

Coronary artery dissection after blunt chest trauma has rarely been reported in traumatic cardiac injuries, but it may cause fatal or nonfatal myocardial infarction. We report a case of dissection of the left main coronary artery, which resulted in acute myocardial infarction 5 weeks after blunt chest trauma. Multidetector-row computed tomography performed prior to the onset of infarction depicted intimal flap and dissected cavities.

Coronary Arterial Plaque Characterized by Multislice Computed Tomography Predicts Complications Following Coronary Intervention

BACKGROUND

A reliable, noninvasive assessment of plaque configuration would constitute an important step forward for predicting complications following percutaneous coronary intervention (PCI). Multislice computed tomography (MSCT) holds promise with respect to allowing for differentiation of coronary lesion configuration. However, it has not yet been clarified whether the characteristics of coronary artery plaque measured by MSCT predict complications after PCI. The aim of this study was to investigate the relationship between plaque configuration and complications after coronary intervention in patients with stable angina pectoris.

METHODS

MSCT was performed in patients with angina pectoris who were scheduled for PCI prospectively, and 26 patients (70 +/- 11 years, 18 males) with coronary artery plaque in a stenotic coronary artery measured by MSCT were recruited for this study. Thirty-five plaques in the stenotic coronary lesions were divided into 3 groups based on the CT density as soft, intermediate, and hard, and were compared with the complications after PCI.

RESULTS

The soft plaque group before PCI (n = 11) was significantly associated with the appearance of slow flow (n = 4) or a compromised side branch (n = 1) after PCI, whereas the hard plaque group before PCI (n = 17) was associated with the appearance of dissection (n = 2) or perforation (n = 1) after PCI (P = 0.004). The intermediate plaque group (n = 7) had only one complication, a compromised side branch (n = 1).

CONCLUSION

Coronary arterial plaque characterized by MSCT can predict intervention-related complication. It may be important for the risk stratification of the patients scheduled to undergo PCI to investigate plaque configuration by MSCT.

Multidetector-Row Computed Tomography Coronary Angiography Optimization of Image Reconstruction Phase According to the Heart Rate

BACKGROUND

To optimize the image reconstruction phase of multidetector-row computed tomography (MDCT) coronary angiography according to the heart rate is crucial.

METHODS AND RESULTS

Scan data were reconstructed for 10 different phases in 58 sequential patients who underwent 8-row cardiac MDCT. The obtained images were scored and compared in terms of motion artifacts and visibility of the vessels, and moreover, ECG record-based evaluations were added for clarification of the temporal relationships among these 10 phases. In the cases with lower heart rates (<65 beats/min), the best quality images were obtained when the end of the image reconstruction phase was positioned at the peak of the P wave. In some cases with higher heart rates (>65 beats/min), they were obtained in the late systolic period.

CONCLUSION

As the heart rate increased, the optimal image reconstruction phase changed from mid diastole to late systole. However, it is recommended to try to decrease the heart rate of patients before data acquisition.

Diagnosis of anomalous origin of the right coronary artery using multislice computed tomography: evaluation of possible causes of myocardial ischemia

Anomalous origin of the right coronary artery (RCA) is a rare condition, but may cause myocardial ischemia and sudden death. Multislice computed tomography, which allows three-dimensional visualization of the coronary artery with high spatial resolution, may be the most promising imaging modality for diagnosing this anomaly. We describe a patient with anomalous origin of the RCA arising from the left sinus of Valsalva. Volume rendering, and axial and curved multiplanar images showed stenosis in the proximal portion of the RCA that coursed between the aorta and the pulmonary artery, and an acute angled take-off of the RCA from the aorta. Three-dimensional virtual angioscopic images showed a hypoplastic RCA orifice and luminal narrowing in the proximal portion of the RCA. Multislice computed tomography was thought to be useful for detecting anomalous origin of the RCA and for evaluating possible causes of myocardial ischemia.

Multislice computed tomographic findings of the anomalous origins of the right coronary artery: evaluation of possible causes of myocardial ischemia

BACKGROUND

Anomalous right coronary arteries (RCA) arising from the left sinus of Valsalva may cause myocardial ischemia.

OBJECTIVE

We evaluated morphological features of anomalous RCA by using multislice computed tomography (MSCT) in relation to myocardial ischemia provoked by myocardial perfusion single-photon emission computed tomography.

METHODS

MSCT was performed in a total of 3, 212 patients by using an Aquillion 16 and a Light Speed Ultra. Retrospective ECG-gated image reconstruction was performed. Volume rendering, axial and curved multiplanar reformatted images were analyzed for the determination of the origin and course of the RCA, the take-off angle of the RCA from the aorta, and size of the RCA orifice. Furthermore, virtual angioscopic images were also used for the evaluation of the RCA orifice structure.

RESULTS

Anomalous origins of the RCA were found in 15 patients. In 13 patients, the RCA arose from the left sinus of Valsalva, and in 2 patients it arose from the left main coronary artery as a single coronary artery. The RCA coursed anteriorly between the ascending aorta and pulmonary artery in 14 patients, whereas it had a retroaortic course in 1 patient. Acute angle take-off (<30 degrees ) of the RCA from the aorta and the left main coronary artery was observed in 8 patients, intramural course of the RCA within the aortic wall was observed in 6 patients and a small RCA orifice was observed in 4 patients. Exercise-induced myocardial ischemia was present in 5 patients.

CONCLUSION

Coursing between the aorta and pulmonary artery, acute angle take-off and intramural course were thought to be major causes of exercise-induced ischemia in patients with anomalous origins of the RCA.

Diagnostic accuracy of 64-slice computed tomography for detecting angiographically significant coronary artery stenosis in an unselected consecutive patient population: comparison with conventional invasive angiography

BACKGROUND

Multislice computed tomography (MSCT) is a promising noninvasive method of detecting coronary artery disease (CAD). However, most data have been obtained in selected series of patients. The purpose of the present study was to investigate the accuracy of 64-slice MSCT (64 MSCT) in daily practice, without any patient selection.

METHODS AND RESULTS

Using 64-slice MSCT coronary angiography (CTA), 69 consecutive patients, 39 (57%) of whom had previously undergone stent implantation, were evaluated. The mean heart rate during scan was 72 beats/min, scan time 13.6 s and the amount of contrast media 72 mL. The mean time span between invasive coronary angiography (ICAG) and CTA was 6 days. Significant stenosis was defined as a diameter reduction of > 50%. Of 966 segments, 884 (92%) were assessable. Compared with ICAG, the sensitivity of CTA to diagnose significant stenosis was 90%, specificity 94%, positive predictive value (PPV) 89% and negative predictive value (NPV) 95%. With regard to 58 stented lesions, the sensitivity, specificity, PPV and NPV were 93%, 96%, 87% and 98%, respectively. On the patient-based analysis, the sensitivity, specificity, PPV and NPV of CTA to detect CAD were 98%, 86%, 98% and 86%, respectively. Eighty-two (8%) segments were not assessable because of irregular rhythm, calcification or tachycardia.

CONCLUSION

Sixty-four-MSCT has a high accuracy for the detection of significant CAD in an unselected patient population and therefore can be considered as a valuable noninvasive technique.

Angle-independent measure of motion for image-based gating in 3D coronary angiography

The role of three-dimensional (3D) image guidance for interventional procedures and minimally invasive surgeries is increasing for the treatment of vascular disease. Currently, most interventional procedures are guided by two-dimensional x-ray angiography, but computed rotational angiography has the potential to provide 3D geometric information about the coronary arteries. The creation of 3D angiographic images of the coronary arteries requires synchronization of data acquisition with respect to the cardiac cycle, in order to minimize motion artifacts. This can be achieved by inferring the extent of motion from a patient's electrocardiogram (ECG) signal. However, a direct measurement of motion (from the 2D angiograms) has the potential to improve the 3D angiographic images by ensuring that only projections acquired during periods of minimal motion are included in the reconstruction. This paper presents an image-based metric for measuring the extent of motion in 2D x-ray angiographic images. Adaptive histogram equalization was applied to projection images to increase the sharpness of coronary arteries and the superior-inferior component of the weighted centroid (SIC) was measured. The SIC constitutes an image-based metric that can be used to track vessel motion, independent of apparent motion induced by the rotational acquisition. To evaluate the technique, six consecutive patients scheduled for routine coronary angiography procedures were studied. We compared the end of the SIC rest period (rho) to R-waves (R) detected in the patient's ECG and found a mean difference of 14 +/- 80 ms. Two simultaneous angular positions were acquired and rho was detected for each position. There was no statistically significant difference (P = 0.79) between rho in the two simultaneously acquired angular positions. Thus we have shown the SIC to be independent of view angle, which is critical for rotational angiography. A preliminary image-based gating strategy that employed the SIC was compared to an ECG-based gating strategy in a porcine model. The image-based gating strategy selected 61 projection images, compared to 45 selected by the ECG-gating strategy. Qualitative comparison revealed that although both the SIC-based and ECG-gated reconstructions decreased motion artifact compared to reconstruction with no gating, the SIC-based gating technique increased the conspicuity of smaller vessels when compared to ECG gating in maximum intensity projections of the reconstructions and increased the sharpness of a vessel cross section in multi-planar reformats of the reconstruction.

[Evaluation of change in the optimal image reconstruction phase in retrospective ECG-gated reconstruction]

The purpose of this study was to optimize the reconstruction phase in order to improve depiction of the coronary artery in the relative delay method of the retrospective electrocardiogram (ECG)-gated reconstruction technique using a multi-slice computed tomography (MSCT) scanner with four channels. The following items were evaluated; 1) image quality of the coronary arteriogram, 2) degree of difference between the standard phase corresponding to the diastasis period and the selected phase, which was determined in each case to obtain the best image, and 3) the factors causing the phase difference. The image quality in the selected phase was better than that in the standard phase. A positive correlation was observed between the degree of phase difference and the median value and standard deviation of the heart rate. The degradation of image quality was remarkable in cases showing a large degree of phase difference. A negative correlation was observed between image quality in the selected phase and the degree of phase difference. Individualizing the reconstruction phase is required to improve the image quality of coronary arteriograms with MSCT. It should be noted that the condition of a low and stable heart rate results in reduction in the degree of phase difference, which is useful for the acquisition of better images.

Contrast enhancement in electron beam tomography of the heart: comparison of a monomeric and a dimeric iodinated contrast agent in 59 patients

RATIONALE AND OBJECTIVES

The aim of the study is to determine whether intravascular time-density course and visualization of the coronary arteries differ with use of a hyperosmolar monomeric versus an iso-osmolar dimeric contrast agent in electron beam tomography (EBT) of the heart.

MATERIALS AND METHODS

Fifty-nine patients underwent EBT of the coronary arteries using the monomeric ioversol or the dimeric iodixanol at the same concentration of 320 mg I/mL. Contrast volume was determined relative to body surface area and injected over 40 seconds. Intravascular time-density curves were created for quantitative analysis. For qualitative assessment, visualization of coronary arteries on axial scans and three-dimensional reconstructions was scored. Patients were matched for contrast flow, transit time, and mean pulse rate for statistical analysis.

RESULTS

Ioversol produced a significantly greater increase in intravascular density for up to 30 seconds after injection (P < .01) compared with iodixanol. No difference between the two contrast media was seen in the qualitative assessment.

CONCLUSION

Monomeric and dimeric contrast media differ in their time-density curves at coronary EBT, a reason for which is not apparent. Qualitative evaluation of coronary arteries is not affected by this difference.

Computed tomography assessment of the regression of an atherosclerotic coronary artery plaque

Multislice spiral computed tomography (MSCT) permits the noninvasive visualization of coronary artery stenoses and occlusions, as well as atherosclerotic plaques, in patients with coronary artery disease. This report describes a patient with stable angina pectoris in whom the regression of the plaque and coronary artery remodeling was documented by serial MSCT.

Incremental value of regional wall motion analysis immediately after exercise for the detection of single-vessel coronary artery disease: study by separate acquisition, dual-isotope ECG-gated single-photon emission computed tomography

BACKGROUND

Although the detection of wall motion abnormalities gives incremental value to myocardial perfusion single-photon emission computed tomography (SPECT) in the diagnosis of extensive coronary artery disease (CAD) and high-grade single-vessel CAD, whether or not it is useful in the diagnosis of mild, single-vessel CAD has not been studied previously.

METHODS AND RESULTS

Separate acquisition, dual isotope ECG-gated SPECT was performed in 97 patients with a low likelihood of CAD (Group 1) and 46 patients with single-vessel CAD (Group 2). Mild CAD was defined by stenosis of 50-75% (Group 2a, n=22) and moderate to severe CAD was defined by stenosis >/=76% (Group 2b, n=24). Myocardial perfusion and wall motion were graded by a 5 point-scale, 20-segment model. The sensitivity of myocardial perfusion alone was 50% for Group 2a, 83% for Group 2b and 67% for Group 2 as a whole. The overall specificity was 90%. When the wall motion analysis was combined, the sensitivity was increased to 82% in Group 2a and 92% in Group 2b.

CONCLUSION

The ability to detect a wall motion abnormality immediately after exercise gives incremental diagnostic value to myocardial perfusion SPECT in the identification of mild, single-vessel CAD.

Detection of coronary plaque by computed tomography with a novel plaque analysis system, 'Plaque Map', and comparison with intravascular ultrasound and angioscopy

BACKGROUND

Previous reports suggest that plaque may be characterized by the computed tomography (CT) number, but there is not a comprehensive method for evaluating the gray-scale CT image of the coronary artery obtained by multi-detector row CT (MDCT).

METHODS AND RESULTS

Forty-five patients with acute coronary syndrome (ACS) underwent MDCT either 3-4 weeks after the onset of acute myocardial infarction (n=24) or within 1 week after percutaneous coronary intervention in patients with unstable angina (UA; n=21). The cross-sections obtained at intervals of 5 mm were converted to numerical data and a 'plaque map' was drawn using the color-based isometric line method and bird's eye view. 'Plaque map' was compared with the findings of intravascular ultrasound (IVUS) and angioscopy. Of 662 slices of 78 vessels, soft, intermediate or calcified plaque was detected in 144, 134, and 84 slices, respectively. Compared with IVUS, the sensitivities were 92%, 87%, and 89%, respectively, and compared with angioscopy, sensitivity was 80% and specificity was 87%.

CONCLUSIONS

MDCT with the 'Plaque Map' system can noninvasively characterize plaque in patients with ACS.

Assessment of coronary artery abnormalities by multislice spiral computed tomography in adolescents and young adults with Kawasaki disease

Multislice spiral computed tomography was performed in 16 adolescents and young adults who had Kawasaki's disease to assess coronary artery abnormalities. Adequate images were obtained for 96% of major coronary segments. The sensitivity of multislice spiral computed tomography to detect coronary artery aneurysms was 100%, and that for significant stenoses and occlusions was 87.5%, whereas false-positive results due to severe calcification was present in 5 arteries and those due to cardiac motion artifact were present in 2, resulting in a specificity of 92.5%.

Evaluation of coronary artery remodeling in patients with acute coronary syndrome and stable angina by multislice computed tomography

BACKGROUND

Multislice computed tomography (MSCT) was used to evaluate coronary artery remodeling in patients with acute coronary syndrome (ACS) and stable angina (SA).

METHODS AND RESULTS

MSCT was performed in 31 patients with ACS and 26 patients with SA and intravascular ultrasound (IVUS) was performed in 28 of these 57 patients. In both the MSCT and IVUS analyses, coronary artery remodeling was assessed by the remodeling index (RI): RI >1.10 was defined as positive coronary artery remodeling (PCAR) and RI <0.95 was defined as negative coronary artery remodeling (NCAR). The RI assessed by MSCT closely correlated with that of IVUS (r=0.86, n=28). The vessel area at the region of maximum luminal narrowing was also comparable between the MSCT and IVUS measurements (r=0.92). PCAR was present in 19 patients (61.3%) with ACS, but in none of the patients with SA (p<0.0001). However, NCAR was present in only 1 patient with ACS (3.2%), but was present in 18 patients (62.9%) with SA. The RI was significantly larger in patients with ACS (1.19+/-0.18) than in those with SA (0.89+/-0.10, p<0.0001).

CONCLUSION

MSCT accurately assesses coronary artery remodeling.

Efficacy of Multislice Computed Tomography for the Detection of Acute Coronary Syndrome in the Emergency Department

BACKGROUND

The diagnosis of acute coronary syndrome (ACS), especially non-ST-elevation myocardial infarction and unstable angina in the emergency department (ED) still remains a challenge. Multislice computed tomography (MSCT) allows assessment of not only coronary artery stenoses and occlusions, but also assessment of coronary artery plaques and myocardial perfusion status.

METHODS AND RESULTS

MSCT was performed in 31 patients who were admitted to the ED because of chest pain persisting at least 30 min and non-diagnostic ECG changes and normal serum enzyme concentrations. Using MSCT, ACS was defined by coronary artery stenosis > or = 75% accompanied by computed tomography (CT)-low-density plaques, and/or by the presence of myocardial perfusion defects. ACS was confirmed by coronary stenosis > or = 75% by coronary angiography and/or subsequent elevation of troponin I concentration. In total, 22 patients were diagnosed as having ACS. MSCT detected stenoses with CT-low-density plaques in 21 and non-transmural myocardial perfusion defect in 3 patients. There was 1 false-positive and 1 false-negative result. The sensitivity and specificity of MSCT to identify ACS was 95.5% and 88.9%, respectively.

CONCLUSION

MSCT provides diagnostic operating characteristics suitable for triage of patients with ACS in the ED.

Applicability of ECG-Gated Multislice Helical CT to Patients With Atrial Fibrillation

BACKGROUND

Multislice computed tomography coronary angiography (CTCA) is reconstructed by ECG gating and consequently it is difficult to obtain coronary artery images from patients with arrhythmias, such as atrial fibrillation (AF), by the conventional method.

METHODS AND RESULTS

Eleven patients with AF (9 males, 2 females; mean age: 62.5 years) underwent CTCA using a slice thickness of 0.5 mm, gantry rotation of 0.4 or 0.5 s/rot and pitch of 3.2-4.0. A segmented reconstruction method was used to construct CTCA images at the conventional relative 70-75% (mid-diastolic phase) and 30-35% (end-systolic phase) of the R-R interval and furthermore, the absolute mid-diastolic phase and end-systolic phase from the R wave. Three investigators, who were unaware of the coronary angiography results, independently evaluated the curved multiplanar reconstruction (MPR) images. In both the relative and absolute phase reconstruction, there were motion artifacts in the mid-diastolic than in the end-systolic phase. The absolute phase images had less motion artifacts than the conventional relative phase images. Optimal curved MPR images were obtained in the absolute end-systolic phase. The quality and motion artifacts of those optimal images from AF patients were similar to those from patients in sinus rhythm.

CONCLUSION

The absolute end-systolic phase is the best time to get optimal CTCA images in AF patients.

Detection of Anomalous Origins of the Coronary Artery by Means of Multislice Computed Tomography

BACKGROUND

Anomalous origins of the coronary artery are rare, but may cause myocardial ischemia and sudden death. Thus, their reliable identification is crucial for any imaging method that attempts coronary artery visualization and of those available multislice computed tomography (MSCT), which provides excellent spatial resolution, may be the most promising.

METHODS AND RESULTS

In consecutive 1,153 patients, MSCT identified 5 patients (0.43 %) with an anomalous origin of the coronary artery. The left circumflex artery (LCX) originated from the right sinus of Valsalva in 1 patient, and the right coronary artery originated from the left sinus of Valsalva and coursed between the aortic root and the pulmonary artery in 3 patients. In 1 patient, MSCT identified the absence of the LCX and high-grade atherosclerotic stenosis in the right coronary artery.

CONCLUSION

MSCT can detect the anomalous origin and course of the coronary artery in relation to the great vessels. It is also useful for identifying atherosclerotic coronary artery disease superimposed on the anomalous vascular system.

Three-Dimensional Visualization of the Coronary Venous System Using Multidetector Row Computed Tomography

BACKGROUND

This study was undertaken to investigate the applicability and image quality of contrast-enhanced visualization of the coronary venous system (CVS) by multidetector row computed tomography (MDCT).

METHODS AND RESULTS

A total of 70 patients underwent MDCT and for each patient, 6 data sets were created throughout the cardiac cycle. The number and location of coronary veins were evaluated in 3-dimensional images using the 6 data sets. The quality of all images reconstructed from the 6 data sets was too poor to evaluate the CVS in 6 patients (9%). In the remaining 64 patients (91%), the diameter of the CVS was usually greater in the images reconstructed from data acquired during systole than in those reconstructed from data acquired during diastole. However, artifacts were observed more often in images from systole than from diastole. The coronary sinus and middle cardiac vein were visible in all 64 patients. The left marginal and posterior veins also were identified in 54 (84%) and 60 patients (94%), respectively.

CONCLUSIONS

MDCT can be used as a non-invasive modality for evaluating the CVS anatomy in most patients.

Evaluation by Multislice Computed Tomography of Atherosclerotic Coronary Artery Plaques in Non-Culprit, Remote Coronary Arteries of Patients With Acute Coronary Syndrome

BACKGROUND

Patients with acute coronary syndrome (ACS) frequently have vulnerable plaques in the remote coronary arteries, suggesting that ACS is part of the pan-coronary process. In the present study the computed tomography (CT) plaque density in non-culprit atherosclerotic coronary artery lesions was evaluated by multislice computed tomography (MSCT) in patients with ACS and non-ACS.

METHODS AND RESULTS

MSCT was performed in 21 patients with ACS and 53 patients with non-ACS: 16 of the 21 ACS patients (76%) and 30 of the non-ACS 53 patients (57 %) had non-calcified plaques in the non-culprit coronary arteries (p=0.18). CT-low-density plaques (CT density <68 Hounsfield units (HU)) were more frequent in the ACS group (13/16 patients, 81%) than in the non-ACS group (13/30 patients, 43%, p=0.03). In addition, the CT density of the non-culprit lesion was significantly lower in patients with ACS than in those with non-ACS (44.1+/-22.9 and 77.3+/-33.7 HU, respectively).

CONCLUSION

Patients with ACS more frequently had CT-low-density plaques in the non-culprit, remote arteries than those with non-ACS, which suggests that ACS treatment should focus not only on stabilizing the culprit lesion but also on systemic stabilization of non-culprit lesions.

Evaluation of Plaque Texture by Means of Multislice Computed Tomography in Patients With Acute Coronary Syndrome and Stable Angina

BACKGROUND

In the present study, multislice spiral computed tomography (MSCT), which allows non-invasive assessment of coronary artery plaque, was used to compare the CT density of plaque between patients with acute coronary syndrome (acs) and those with stable angina (sa).

METHODS AND RESULTS

MSCT was performed in 20 patients with ACS (17 with acute myocardial infarction, 3 with unstable angina) and 22 patients with SA. The presence of the plaque was defined on the basis of multiplanar reformation and axial images. At least 4 regions of interest were then placed within the plaque and the minimum CT density was measured and expressed as Hounsfield units (HU). The number of plaques did not differ between the 2 groups, but the minimum CT density was significantly lower in patients with ACS (25+/-15 HU) than in those with SA (71+/-16 HU, range 46-101 HU, p<0.001). Similarly, the minimum plaque density was significantly lower in the culprit coronary segment (26+/-16 HU) than in the non-culprit segment (48+/-17 HU) in 15 ACS patients with multiple plaques.

CONCLUSION

MSCT can potentially differentiate vulnerable from stable plaque in patients with coronary artery disease, although long-term, prospective analysis is needed to establish the conclusion.

New Method of Measuring Coronary Diameter by Electron-Beam Computed Tomographic Angiography Using Adjusted Thresholds Determined by Calibration With Aortic Opacity

BACKGROUND

In a previous study the adjusted thresholds at which the diameters of coronary arteries determined by enhanced electron-beam computed tomography (CT) scans are equal to the corresponding quantitative coronary angiography measurements were analyzed, and their correlation with maximum CT values for the vessel short axes was determined. A rapid accurate method for such measurements was sought by substituting maximum CT values for the descending aorta in the corresponding axial images for those for the short axes.

METHODS AND RESULTS

In 8 patients, 179 sites were measured. Means (+/- SD) of adjusted thresholds and the maximum CT values for vessel short axes and the descending aorta in the corresponding axial images for all vessels were 108 +/-66, 227+/-80, and 363+/-75 Hounsfield Unit (HU), respectively. Adjusted thresholds correlated with the maximum CT values for the corresponding vessel short axes and the descending aorta in the corresponding axial images, with R2=0.55, 0.33, p<0.01, respectively. An abbreviated formula for use of maximum CT values for the descending aorta in the corresponding axial images was y=0.5x-75 (HU) (y= adjusted threshold, x= maximum CT value for the descending aorta in the corresponding axial image).

CONCLUSIONS

The abbreviated formula provided a rapid, accurate method for measurements independent of arterial enhancement.

A Coronary Artery Fistula With Saccular Aneurysm Mimicking a Right Atrial Cystic Mass

A 16 year-old Korean girl with cardiomegaly was found to have a "right atrial cystic mass" on transthoracic echocardiography. An unusual cystic structure made the diagnosis difficult. However, transesophageal echocardiography and multidetector computed tomography revealed a coronary artery fistula with a distal saccular aneurysm involving the interatrial septum and draining into the right atrium. Multidetector computed tomography provided clear anatomic visualization that fully delineated the abnormal structures. Multidetector computed tomography may be considered as a good alternative for transesophageal echocardiography in assessing a tortuous coronary artery fistula and aneurysm with complex anatomy.

Noninvasive assessment of coronary artery disease by multislice spiral computed tomography using a new retrospectively ECG-gated image reconstruction technique

The present study was designed to investigate the accuracy of multislice spiral computed tomography (MSCT) in detecting coronary artery disease, compared with coronary angiography (CAG), using a new retrospectively ECG-gated reconstruction method that reduced cardiac motion artifact. The study group comprised 54 consecutive patients undergoing MSCT and CAG. MSCT was performed using a SOMATOM Volume Zoom (4-detector-row, Siemens, Germany) with slice thickness 1.0 mm, pitch 1.5 (table feed: 1.5 mm per rotation) and gantry rotation time 500 ms. Metoprolol (20-60 mg) was administered orally prior to MSCT imaging. ECG-gated image reconstruction was performed with the reconstruction window (250 ms) positioned immediately before atrial contraction in order to reduce the cardiac motion artifact caused by the abrupt diastolic ventricular movement occurring during the rapid filling and atrial contraction periods. Following inspection of the volume rendering images, multiplanar reconstruction images and axial images of the left main coronary artery (LMCA), left anterior descending artery (LAD), left circumflex artery (LCx) and right coronary artery (RCA) were obtained and evaluated for luminal narrowing. The results were compared with those obtained by CAG. Of 216 coronary arteries, 206 (95.4%) were assessable; 10 arteries were excluded from the analysis because of severe calcification (n=4), stents (n=3) or insufficient contrast enhancement (n=3). The sensitivity to detect coronary stenoses >or=50% was 93.5% and the specificity to define luminal narrowing <50% was 97.2%. The positive predictive value and the negative predictive value were 93.5% and 97.2%, respectively. The sensitivity was still satisfactory (80.6%) even when non-assessable arteries were included in the analysis. The new retrospectively ECG-gated reconstruction method for MSCT has excellent diagnostic accuracy in detecting significant coronary artery stenoses.

Detection of coronary artery aneurysms, stenoses and occlusions by multislice spiral computed tomography in adolescents with kawasaki disease

In patients with Kawasaki disease (KD), serial evaluation of coronary artery aneurysms (CAAs) and luminal narrowing is essential for risk stratification and therapeutic management. Therefore, non-invasive assessment of the status of the coronary artery is of utmost importance in patient management. Multislice spiral computed tomography (MSCT) permits non-invasive visualization of the entire coronary artery system and was used in the evaluation of 4 patients with KD. CAAs and high-grade coronary artery stenoses were detected by MSCT and corroborated the findings of coronary angiograms performed within the previous 2 years. MSCT has the potential to be the standard diagnostic tool in adolescents with KD.