Left Ventricular Diastolic Dysfunction Assessment with Dual-Source CT.

PURPOSE: To assess the impact of left ventricular (LV) diastolic dysfunction on left atrial (LA) phasic volume and function using dual-source CT (DSCT) and to find a viable alternative prognostic parameter of CT for LV diastolic dysfunction through quantitative evaluation of LA phasic volume and function in patients with LV diastolic dysfunction. MATERIALS AND METHODS: Seventy-seven patients were examined using DSCT and Doppler echocardiography on the same day. Reservoir, conduit, and contractile function of LA were evaluated by measuring LA volume (LAV) during different cardiac phases and all parameters were normalized to body surface area (BSA). Patients were divided into four groups (normal, impaired relaxation, pseudonormal, and restrictive LV diastolic filling) according to echocardiographic findings. The LA phasic volume and function in different stages of LV diastolic function was compared using one-way ANOVA analysis. The correlations between indexed volume of LA (LAVi) and diastolic function in different stages of LV were evaluated using Spearman correlation analysis. RESULTS: LA ejection fraction (LAEF), LA contraction, reservoir, and conduit function in patients in impaired relaxation group were not different from those in the normal group, but they were lower in patients in the pseudonormal and restrictive LV diastolic dysfunction groups (P < 0.05). For LA conduit function, there were no significant differences between the patients in the pseudonormal group and restrictive filling group (P = 0.195). There was a strong correlation between the indexed maximal left atrial volume (LAVmax, r = 0.85, P < 0.001), minimal left atrial volume (LAVmin, r = 0.91, P < 0.001), left atrial volume at the onset of P wave (LAVp, r = 0.84, P < 0.001), and different stages of LV diastolic function. The LAVi increased as the severity of LV diastolic dysfunction increased. CONCLUSIONS: LA remodeling takes place in patients with LV diastolic dysfunction. At the same time, LA phasic volume and function parameters evaluated by DSCT indicated the severity of the LV diastolic dysfunction. Quantitative analysis of LA phasic volume and function parameters using DSCT could be a viable alternative prognostic parameter of LV diastolic function.

Coronary artery vasculitis: assessment with cardiac multi-detector computed tomography.

Coronary artery vasculitis is rare and comprises an array of inflammatory diseases. It often results in severe and life-threatening complications, including coronary artery aneurysm, coronary artery stenosis, intraluminal thrombosis, and microcirculation abnormalities. These may occur at a young age and are often silent in the early phases. Invasive coronary angiography is the gold standard for diagnosing coronary artery disease (CAD); however, multi-detector computed tomography (MDCT) is now widely regarded as a powerful non-invasive tool for the detection of CAD. It is important for clinicians to recognize the various CT findings associated with coronary artery vasculitis in order to promote accurate diagnosis and proper patient management. The purpose of this article is to present an overview of the conditions associated with coronary artery vasculitis, with an emphasis on etiology and cardiac MDCT diagnosis of CAD. Cardiac MDCT is clinically useful and can provide information for the accurate diagnosis and treatment of coronary vasculitis.

Grade-response relationship between blood pressure and severity of coronary atherosclerosis in asymptomatic adults: assessment with coronary CT angiography.

Hypertension is known to be a strong risk factor for coronary atherosclerosis. We aimed to investigate the prevalence, severity, and plaque characteristics of coronary atherosclerosis according to grade of blood pressure (BP) using coronary CT angiography (CCTA) in asymptomatic adults. We enrolled 8,238 asymptomatic subjects who underwent coronary artery calcium scoring (CACS) and CCTA for health screening purposes. Subjects were classified according to JNC 7 guidelines (normal, systolic BP/diastolic BP < 120/80; pre-hypertension [PH], 120-139/80-89; hypertension stage 1 [H1], 140-159/90-99; hypertension stage 2 [H2], >160/100). Isolated systolic hypertension (ISH; systolic BP > 140, diastolic BP < 80) was additionally categorized. With CCTA, the presence of plaques, severity of stenosis, and plaque types were assessed. Using multiple logistic regression analysis, the adjusted odds ratios (AORs) for plaque, obstructive coronary artery disease (CAD) (luminal stenosis ≥50 %), non-calcified plaque (NCP), and CACS > 100 were assessed according to BP grade. After adjustment for clinical risk factors, the risk of subclinical atherosclerosis, NCP, and CACS > 100 gradually increased from PH stage (all P values for trend <0.05), while the risk of obstructive CAD increased from the H1 stage (AORs of H1 and H2: 1.70 and 2.33, respectively). In the ISH group, the AOR of subclinical atherosclerosis (1.64) was higher than in the H1 group (1.55), while the AOR of obstructive CAD (2.58) was higher than in the H2 group (2.33). Therefore, our study strongly suggests that coronary atherosclerosis in asymptomatic adults shows a grade-response relationship according to hypertension grade.

The prevalence and characteristics of coronary atherosclerosis in asymptomatic subjects classified as low risk based on traditional risk stratification algorithm: assessment with coronary CT angiography.

OBJECTIVE: To evaluate the prevalence and characteristics of coronary atherosclerosis in asymptomatic subjects classified as low risk by National Cholesterol Education Program (NCEP) guideline using coronary CT angiography (CCTA). DESIGN: An observational study. SETTING: A single tertiary referral centre. PATIENTS: 2133 (49.2%) subjects, who were classified as low risk by the NCEP guideline, of 4339 consecutive middle-aged asymptomatic subjects who underwent CCTA with 64-slice scanners as part of a general health evaluation. MAIN OUTCOME MEASURES: The incidence of atherosclerosis plaques, significant stenosis. RESULTS: In the subjects at low risk, 11.4% (243 of 2133) of subjects had atherosclerosis plaques, 1.3% (28 of 2133) of subjects had significant stenosis, and 0.8% (18 of 2133) of subjects had significant stenosis caused by non-calcified plaque (NCP). Especially, 75.0% (21 of 28) of subjects with significant stenosis and 94.4% (17 of 18) of subjects with significant stenosis caused by NCP were young adults. Mid-term follow-up (29.3 ± 14.9 months) revealed four subjects with cardiac events: three subjects with unstable angina requiring hospital stay and one subject with percutaneous coronary intervention. CONCLUSIONS: Although an asymptomatic population classified as low risk by the NCEP guideline has been regarded as a minimal risk group, the prevalence of atherosclerosis plaques and significant stenosis were not negligible. However, considering very low event rate for those patients, CCTA should not be performed in low-risk asymptomatic subjects, although CCTA might have the potential for identification of high-risk groups in the selected subjects regarded as a minimal-risk group by NCEP guideline.

JPEG2000 compression of CT images used for measuring coronary artery calcification score: assessment of optimal compression threshold.

OBJECTIVE: The purpose of our study was to assess the acceptable compression threshold for JPEG2000 compression of CT images used for measuring coronary artery calcification scores (CACS) in terms of variability. MATERIALS AND METHODS: In a retrospective review, 80 patients who had undergone CT for determination of the CACS were compiled in four subsets (20 scans each) according to CACS: 0, subset A; > 0 to ≥ 100, subset B; > 100 to ≤ 400, subset C; and > 400, subset D. Each scan was compressed using eight compression ratios (CRs). We measured the CACS on all 720 CT scans (80 original and 640 compressed scans). For each compressed scan, the variability in CACS was evaluated by comparing with the CACS of the corresponding original CT scan. RESULTS: For each subset and each CR, we determined whether the upper limit of the one-sided 95% CI of the variability in CACS exceeded 5%. The variability in CACS tended to increase as the CR increased and tended to decrease in the order of increasing CACSs at each CR (i.e., subset B > subset C > subset D). With 5% as the limit of variability, acceptable compression CRs were between 20:1 and 25:1 for subset B; between 40:1 and 60:1 for subset C; and > 100:1 for subset D. CONCLUSION: A level of 20:1 could be a potentially acceptable threshold for JPEG2000 compression of CT images used for measuring CACS, with 5% of the variability in CACS as the acceptable limit of variability.

Coronary vasospastic angina: assessment by multidetector CT coronary angiography.

OBJECTIVE: We aimed to describe the imaging findings of multidetector CT coronary angiography (MDCTA) in cases of vasospastic angina (VA) and to determine the accuracy of MDCTA in the identification of VA as compared with invasive coronary angiography with an ergonovine provocation test (CAG with an EG test). MATERIALS AND METHODS: Fifty-three patients with clinically suspected VA were enrolled in this study. Two radiologists analyzed the stenosis degree, presence or absence of plaque, plaque composition, and a remodeling index of the related-segment in CAG with an EG test, which were used as a gold standard. We evaluated the diagnostic performances of MDCTA by comparing the MDCTA findings with those of CAG with an EG test. RESULTS: Among the 25 patients with positive CAG with an EG test, all 12 patients with significant stenosis showed no definite plaque with the negative arterial remodeling. Of the six patients with insignificant stenosis, three (50%) had non-calcified plaque (NCP), two (33%) had mixed plaque, and one (17%) had calcified plaque. When the criteria for significant stenosis with negative remodeling but no definite evidence of plaque as a characteristic finding of MDCTA were used, results showed sensitivities, specificities, positive predictive values (PPV), and negative predictive values (NPV) of 48%, 100%, 100%, and 68%, respectively. CONCLUSION: Significant stenosis with negative remodeling, but no definite evidence of plaque, is the characteristic finding on MDCTA of VA. Cardiac MDCTA shows good diagnostic performance with high specificity and PPV as compared with CAG with an EG test.

Significance of noncalcified coronary plaque in asymptomatic subjects with low coronary artery calcium score: assessment with coronary computed tomography angiography.

We aimed to investigate the prevalence and severity of noncalcified coronary plaques (NCP) using coronary CT angiography (CCTA) and analyze predictors of significant coronary stenosis by NCP in asymptomatic subjects with low coronary artery calcium score (CACS). The institutional review board approved this retrospective study and all patients gave written, informed consent. The presence of plaque, severity of stenosis, plaque characteristics, and CACS were assessed in 7,515 asymptomatic subjects. We evaluated the prevalence and severity of NCP in subjects having low CACS (707 subjects; men with CACS from 1 to 50 and women from 1 to 10) in comparison to those having 0 CACS (6,040 subjects) as the reference standard. Conventional risk factors were assessed for predictors of NCP and significant stenosis by NCP. We also investigated the cardiac events of the patients through medical records. Compared to subjects with 0 CACS, those with low CACS showed higher prevalence of NCP (6.9% vs. 31.5%, P < 0.001) and significant stenosis caused by NCP (0.8% vs. 7.5%, P < 0.001). In the low CACS group, independent predictors for significant NCP included diabetes mellitus (DM), hypertension, and elevated low-density lipoprotein (LDL)-cholesterol (all P < 0.05). However, 47.2% of subjects with significant NCP were classified into the low to intermediate risk according to Framingham Risk Score. At the median follow up of 42 months (range: 3-60 months), cardiac events were significantly higher in the low CACS group compared to the 0 CACS group (2.6% vs. 0.27%, P < 0.001). In asymptomatic subjects having low CACS, the prevalence and severity of NCP were higher as compared to subjects having zero CACS and predictors of significant stenosis by NCP were DM, hypertension and LDL-Cholesterol. Therefore, CCTA may be useful for risk stratification of coronary artery disease as added value over CACS in selected populations with low CACS who have predictors of significant NCP.

Reproducibility in the assessment of noncalcified coronary plaque with 256-slice multi-detector CT and automated plaque analysis software.

We aimed to assess intra- and inter-observer reproducibility in evaluating volume and characteristics of non-calcified coronary plaques (NCPs) using a 256-slice multi-detector computed tomography (MDCT) angiography and dedicated automated plaque analysis software in asymptomatic individuals. Forty-two NCPs from 39 patients with a vessel diameter >2 mm were evaluated using a 256-slice MDCT with dedicated automated plaque analysis software. Two independent observers analyzed the characteristics of NCPs, including plaque volume (vol), mean CT number of the NCPs in Hounsfield units (HU(mean)), and remodeling index (RI). One of the observers repeated the evaluation of all datasets after an interval of at least 4 weeks. Bland-Altman analysis and concordance correlation coefficients (CCCs) were used to determine intra- and inter-observer variability. For vol measurements, the 95% limits of agreement were -21.6 and 13.2 mm(3), and -24.6 and 20.3 mm(3) for intra- and inter-observer variability, respectively. For HU(mean) measurements, the 95% limits of agreement were -22.2 and 20.8 HU, and -21.1 and 21.0 HU for intra- and inter-observer variability, respectively. For RI measurements, the 95% limits of agreement were -0.38 and 0.39, and -0.51 and 0.36 for intra- and inter-observer variability, respectively. The CCCs was very high for all measurements, ranging from 0.90 to 0.98. Using 256-slice MDCT with dedicated automated plaque analysis software, intra- and inter-observer reproducibility were excellent in evaluating the volume and characteristics of NCP in asymptomatic individuals.

Hypertrophic cardiomyopathy: assessment with MR imaging and multidetector CT.

Hypertrophic cardiomyopathy (HCM) is a genetic cardiac disease. Its early detection is important because it is the most common cause of sudden cardiac death among young people. However, HCM is often a dilemma for clinicians because it manifests with diverse phenotypic expressions and clinical courses. With the advances in imaging technology, magnetic resonance (MR) imaging and multidetector computed tomography (CT) serve as suitable modalities for detecting and characterizing HCM and obtaining information for appropriate management of cases of HCM, although echocardiography is currently the most widely used modality. This article is an overview of the definition of HCM, its various phenotypes, risk stratification of HCM, and the potential application of cardiac MR imaging and multidetector CT for the assessment of HCM.

Assessment of subclinical coronary atherosclerosis in asymptomatic patients with type 2 diabetes mellitus with single photon emission computed tomography and coronary computed tomography angiography.

We evaluated the characteristics of coronary artery disease in asymptomatic patients with type 2 diabetes mellitus (DM) using single photon emission computed tomography (SPECT) and coronary computed tomographic angiography (CCTA). A total of 116 patients with DM without abnormal electrocardiographic findings or evidence of peripheral arterial disease (number of risk factors > or =2; 62 +/- 7 years, 59% men) underwent CCTA and SPECT. Of the 116 patients with DM, 88 (76%) had a normal single photon emission computed tomographic findings, and 28 (24%) had abnormal perfusion defects. Of the 116 patients, 92 (79%) had atherosclerotic plaques (2 +/- 2 segments per subject), and 20 (17%) had significant stenosis seen on CCTA. Patients with DM and normal findings on SPECT had a similar prevalence of atherosclerotic plaque (78% vs 82%), significant stenosis (15% vs 25%), severe stenosis (7% vs 7%), and calcified (40% vs 43%), mixed (49% vs 57%), and noncalcified plaques (26% vs 29%) and a high (>100) coronary artery calcium score (32% vs 29%; all p >0.05) compared to those with abnormal findings on SPECT. During the mid-term follow-up (24 +/- 4 months), 5 cardiac events occurred in patients with DM and normal findings on SPECT, only in those with occult CAD on CCTA: 1 sudden cardiac death and 4 revascularization procedures. In conclusion, a significant percentage of patients with DM and normal eletrocardiographic findings, no peripheral arterial disease, and normal findings on SPECT have evidence of occult CAD on CCTA. Furthermore, a small percentage had had a cardiac event by mid-term follow-up. SPECT showed limited capability to differentiate the coronary risks between patients with DM and no coronary plaque and from those with a certain degree of disease; 2 circumstances that represent different coronary risks.