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Computed tomography (CT)-derived three-dimensional maximum principal strain (MP-strain) can provide incremental value to coronary CT angiography for cardiac dysfunction assessment with high diagnostic performance in patients with myocardial infarction. Global longitudinal strain (GLS) measured using two-dimensional speckle tracking echocardiography (2D-STE) is more sensitive than left ventricular ejection fraction (LVEF) for detecting early myocardial dysfunction. We aimed to compare CT-derived MP-strain with each of 2D-STE-derived strains (i.e., longitudinal, circumferential, and radial strains), and identify the major determinants of CT-derived MP-strain among 2D-STE-derived strains. We studied 51 patients who underwent cardiac CT and echocardiography. CT images were reconstructed at every 5% (0–95%) of the RR interval. A dedicated workstation was used to analyze CT-derived MP-strain on the 16-segment model. We calculated CT-derived global MP-strain with all the 16 segments on a per patient basis. Pearson's test was used to assess correlations between CT-derived MP-strain and STE-strain at global and segmental levels. The intra-class correlation coefficient for interobserver agreement for CT-derived global MP-strain was 0.98 (95% confidence interval 0.96–0.99). The low-CT-derived global MP-strain group (≤ 0.43) had more patients with LV dysfunction than the high-CT-derived global MP-strain group (> 0.43). CT-derived global MP-strain was associated with STE-GLS (r = 0.738, P < 0.001), global circumferential strain (r = 0.646, P < 0.001), and global radial strain (r = 0.432, P = 0.001). In multivariate analysis, STE-GLS had the strongest association to CT-derived global MP-strain among three directional STE-strains and LVEF by echocardiography (standardized coefficient = − 0.527, P < 0.001). STE-GLS is a major determinant of CT-derived global MP-strain. CT-derived MP-strain may enhance the value of coronary CT angiography by adding functional information to CT-derived LVEF. [ABSTRACT FROM AUTHOR]

Objective: The elasticity of the aortic wall varies depending on age, vessel location, and the presence of aortic diseases. Noninvasive measurement will be a powerful tool to understand the mechanical state of the aorta in a living human body. This study aimed to determine the elastic modulus of the aorta using computed tomography images. Methods: We constructed our original formulae based on mechanics of materials. Then, we performed computed tomography scans of a silicon rubber tube by applying four pressure conditions to the lumen. The segment elastic modulus was calculated from the scanned images using our formulae. The actual modulus was measured using a tensile loading test for comparison. Results: The segment moduli of elasticity from the images were 0.525 [0.524, 0.527], 0.524 [0.520, 0.524], 0.520 [0.515, 0.523], and 0.522 [0.516, 0.532] (unit: MPa, median [25%, 75% quantiles]) for the four pressure conditions, respectively. The corresponding measurements in the tensile test were 0.548 [0.539, 0.566], 0.535 [0.528, 0.553], 0.526 [0.513, 0.543], and 0.523 [0.508, 0.530], respectively. These results indicated errors of 4.2%, 2.1%, 1.1%, and 0.2%, respectively. Conclusion: Our formulae provided good estimations of the segment elastic moduli of a silicon rubber tube under physiological pressure conditions using the computed tomography images. Significance: In addition to the elasticity, the formulae provide the strain energy as well. These properties can be better predictors of aortic diseases. The formulae consist of clinical parameters commonly used in medical settings (pressure, diameter, and wall thickness). [ABSTRACT FROM AUTHOR]

• Myocardial volume subtended by coronary artery stenosis (V sub) in obstructive coronary artery disease (CAD) is significantly higher than that in non-obstructive CAD. • V sub is significantly corelated with fractional flow reserve. • V sub may aid in increasing computed tomography-derived myocardial blood flow performance for detecting obstructive CAD. This study aimed to evaluate the combined diagnostic performance of coronary artery stenosis-subtended myocardial volume (V sub) and myocardial blood flow (MBFsub) on computed tomography (CT) for detecting obstructive coronary artery disease (CAD) assessed by invasive coronary angiography (ICA) and fractional flow reserve (FFR). Thirty-nine patients who underwent coronary CT angiography (CTA) and stress dynamic myocardial CT perfusion (CTP) prior to ICA were enrolled. Obstructive CAD was defined as severe (≥70%) or moderate (30–69%) stenosis with FFR ≤0.8 on ICA. The V sub was semi-automatically calculated from coronary CTA data using Voronoi diagram-based myocardial segmentation. The standard CT-MBF based on the 17-segment model was calculated using dynamic stress CTP data and deconvolution analysis. The CT-MBFsub was automatically analyzed by integrating the CT-MBF and Voronoi diagram-based myocardial segmentation analyses. The diagnostic performance of combined CT-MBFsub and V sub assessment was determined using receiver operating characteristic analysis and compared with standard CT-MBF and CT-MBFsub. Of 117 vessels in 39 patients, 72 vessels were suspected of significant stenosis on CTA and 33 vessels had obstructive CAD on ICA and FFR. The sensitivity and specificity for identifying obstructive CAD were 67% and 82% for standard CT-MBF, 70% and 77% for CT-MBFsub, and 85% and 82% for combined CT-MBFsub and V sub assessment. The area under the receiver operating characteristic curve of the combined CT-MBFsub and V sub assessment was significantly higher than those of standard CT-MBF and CT-MBFsub (0.89 vs. 0.75, 0.77; p < 0.05). The V sub may aid in increasing the diagnostic performance of CT-MBFsub for detecting obstructive CAD. [ABSTRACT FROM AUTHOR]

Highlights • Dynamic computed tomography (CT) perfusion allows quantification of myocardial blood flow (MBF). • CT-MBF significantly correlated with fractional flow reserve. • CT-MBF provides incremental diagnostic value for detecting obstructive coronary artery disease. Abstract Background This study aimed to evaluate the incremental diagnostic value of dynamic myocardial computed tomography (CT) perfusion (CTP) imaging for detecting obstructive coronary artery disease (CAD) in comparison with coronary CT angiography (CTA). Methods Thirty-eight patients who had undergone coronary CTA and pharmacological stress dynamic CTP before invasive coronary angiography (ICA) were selected retrospectively. Using ICA, obstructive CAD was defined as the presence of severe (≥70%) or moderate (50–69%) stenosis with fractional flow reserve (FFR) <0.75. For CT evaluations, coronary vessels with any stenosis ≥50%, ≥70% or unassessable lesions were considered significantly stenotic. Dynamic CTP was assessed quantitatively using CT-derived myocardial blood flow (CT-MBF). Receiver operating characteristic (ROC) curve analysis determined the cut-off value of CT-MBF for identifying obstructive CAD. The diagnostic performances of CTA alone and integrated CTA and CTP assessments for detecting obstructive CAD were compared. Results Using ICA and FFR, 24 of 114 vessels had obstructive CAD. The cut-off value of CT-MBF for detecting obstructive CAD was 1.26 mL/g/min. The sensitivity, specificity, and positive and negative predictive values (PPV and NPV) at the vessel level were 96%, 57%, 37%, and 98% for CTA, and 83%, 93%, 77%, and 95% for integrated CTA and CTP assessment using cut-off 50% stenosis on CTA, respectively. The sensitivity, specificity, and PPV and NPV at the vessel level were 79%, 69%, 40%, and 93% for CTA, and 71%, 97%, 85%, and 93% for integrated CTA and CTP assessment using cut-off 70% stenosis on CTA, respectively. The area under the ROC curve for CTA and CTP was significantly higher than that for CTA alone (0.96 vs. 0.84, p < 0.05). Conclusions Stress dynamic myocardial CTP is feasible to detect hemodynamically obstructive CAD in patients with high pre-test likelihood and helps for improving diagnostic performance in comparison with coronary CTA alone. [ABSTRACT FROM AUTHOR]

Objective: To assess the image quality of coronary CT angiography (CCTA) for suspected acute coronary syndrome (ACS) outside office hours.Methods: Patients with symptoms suggestive of an ACS underwent CCTA at the emergency department 24 hours, 7 days a week. A total of 118 patients, of whom 89 (75 %) presented during office hours (weekdays between 07:00 and 17:00) and 29 (25 %) outside office hours (weekdays between 17:00 and 07:00, weekends and holidays) underwent CCTA. Image quality was evaluated per coronary segment by two experienced readers and graded on an ordinal scale ranging from 1 to 3.Results: There were no significant differences in acquisition parameters, beta-blocker administration or heart rate between patients presenting during office hours and outside office hours. The median quality score per patient was 30.5 [interquartile range 26.0-33.5] for patients presenting during office hours in comparison to 27.5 [19.75-32.0] for patients presenting outside office hours (p=0.043). The number of non-evaluable segments was lower for patients presenting during office hours (0 [0-1.0] vs. 1.0 [0-4.0], p=0.009).Conclusion: Image quality of CCTA outside office hours in the diagnosis of suspected ACS is diminished.Key Points: • Quality scores were higher for coronary-CTA during office hours. • There were no differences in acquisition parameters. • There was a non-significant trend towards higher heart rates outside office hours. • Coronary-CTA on the ED requires state-of-the-art scanner technology and sufficiently trained staff. • Coronary-CTA on the ED needs preparation time and optimisation of the procedure. [ABSTRACT FROM AUTHOR]

Background This study aimed to evaluate the feasibility of peak enhancement (PE) ratio of myocardium to aorta (PER) derived from stress dynamic computed tomography myocardial perfusion imaging (CTP) for the detection of myocardial ischemia assessed by magnetic resonance (MR) imaging. Methods Forty-four patients who underwent stress dynamic CTP and MR imaging were retrospectively evaluated. From the time-attenuation curve, myocardial PE, PER, and myocardial blood flow (MBF) were calculated on a segment-based analysis. The correlation between myocardial and aortic PE was assessed by Spearman's correlation, and the differences in myocardial PE and PER between normal and ischemic myocardium were assessed by the Mann–Whitney U -test. The diagnostic accuracies of myocardial PE, PER, and MBF for detecting myocardial ischemia were compared by receiver operating characteristic analysis. Results Of 704 segments, 258 segments (37%) were diagnosed as myocardial ischemia with MR imaging. Myocardial and aortic PE were significantly correlated in both normal and ischemic segments ( r = 0.76 and 0.58; p < 0.05, in each). The myocardial PE and PER of ischemic segments were significantly lower than those of normal segments ( p < 0.05, in each). Sensitivity and specificity were 61% [95% confidence interval (CI), 55–70%] and 83% (95% CI, 73–87%) for myocardial PE, 78% (67–88%) and 82% (95% CI, 70–91%) for PER, and 81% (95% CI, 73–87%) and 85% (95% CI, 79–92%) for MBF. There was a significantly larger area under the curve for PER (0.87; 95% CI, 0.84–0.90) and MBF (0.88; 95%CI, 0.85–0.91), compared to myocardial PE (0.75; 95% CI, 0.70–0.79) ( p < 0.05, in each). There was no significant difference in area under the curve between PER and MBF. Conclusions The semi-quantitative parameter of PER showed a high diagnostic accuracy for the detection of myocardial ischemia, comparable to that of MBF. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the additional value of transmural perfusion ratio (TPR) in dynamic CT myocardial perfusion imaging for detection of haemodynamically significant coronary artery disease compared with fractional flow reserve (FFR).Methods: Subjects with suspected or known coronary artery disease were prospectively included and underwent a CT-MPI examination. From the CT-MPI time-point data absolute myocardial blood flow (MBF) values were temporally resolved using a hybrid deconvolution model. An absolute MBF value was measured in the suspected perfusion defect. TPR was defined as the ratio between the subendocardial and subepicardial MBF. TPR and MBF results were compared with invasive FFR using a threshold of 0.80.Results: Forty-three patients and 94 territories were analysed. The area under the receiver operator curve was larger for MBF (0.78) compared with TPR (0.65, P = 0.026). No significant differences were found in diagnostic classification between MBF and TPR with a territory-based accuracy of 77 % (67-86 %) for MBF compared with 70 % (60-81 %) for TPR. Combined MBF and TPR classification did not improve the diagnostic classification.Conclusions: Dynamic CT-MPI-based transmural perfusion ratio predicts haemodynamically significant coronary artery disease. However, diagnostic performance of dynamic CT-MPI-derived TPR is inferior to quantified MBF and has limited incremental value.Key Points: • The transmural perfusion ratio from dynamic CT-MPI predicts functional obstructive coronary artery disease • Performance of the transmural perfusion ratio is inferior to quantified myocardial blood flow • The incremental value of the transmural perfusion ratio is limited. [ABSTRACT FROM AUTHOR]

Aims Non-culprit plaques are responsible for a substantial number of future events in patients with acute coronary syndrome (ACS). In this study, we evaluated the prognostic implications of non-culprit plaques seen on coronary computed tomography angiography (CTA) in patients with ACS. Methods and results Coronary CTA was performed in 169 patients (mean 59 ± 11 years,129 males) admitted with ACS. Data sets were assessed for the presence of obstructive non-culprit plaques (>50% luminal narrowing), segment involvement score, and quantitative measures of plaque burden, after censoring initial culprit plaques. Follow-up was performed for the occurrence of major adverse cardiovascular events (MACEs) unrelated to the initial culprit plaque; cardiac death, second ACS, or coronary revascularization after 90 days. After a median follow-up of 4.8 (IQR 2.6-6.6) years, MACE occurred in 36 (24%) patients: 6 cardiac deaths, 16 second ACS, and 14 coronary revascularizations. Dyslipidaemia (hazard ratio [HR] 3.1 [95% confidence interval 1.5-6.6]) and diabetes mellitus (HR 4.8 [2.3-10.3]) were univariable clinical predictors of MACE. Patients with remaining obstructive non-culprit plaques (HR 3.66 [1.52-8.80]) and higher plaque burden index (HR 1.22 [1.01-1.48]) had a more risk of MACE. In multivariate analysis, with diabetes, dyslipidaemia, and plaque burden index, obstructive non-culprit plaques (HR 3.76 [1.28-11.09]) remained an independent predictor of MACE. Conclusion Almost a quarter of the study population experienced a new event arising from a non-culprit plaque during a follow-up of almost 5 years. ACS patients with remaining obstructive non-culprit plaques or high plaque burden have an increased risk of future MACE. [ABSTRACT FROM AUTHOR]

Background: Cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) is a valuable technique for detecting myocardial disorders and fibrosis. However, we sometimes observe a linear, mid-wall high intensity signal in the basal septum in the short axis view, which often presents diagnostic difficulties in the clinical setting. The purpose of this study was to compare the linear, mid-wall high intensity in the basal septum identified by LGE with the anterior septal perforator arteries identified by coronary computed tomography angiography (CorCTA). Methods: We retrospectively selected 148 patients who underwent both CorCTA and CMR LGE within 1 year. In the interpretation of LGE, we defined a positive linear high intensity (LHI+) as follows: ① LHI in the basal septum and ② observable for 1.5 cm or more. All other patients were defined as a negative LHI (LHI-). In LHI+ patients, we assessed the correlation between the LHI length and the septal perforator artery length on CorCTA. We also compared the length of the septal perforator artery on CorCTA between LHI+ patients and LHI- patients. Results: A population of 111 patients were used for further analysis. Among these , there were 55 LHI+ patients and 56 LHI- patients. In LHI+ patients, linear regression analysis revealed that there was a good agreement between LGE LHI and septal perforator arteries by CorCTA in terms of length measurements. The measured length of the anterior septal perforator arteries was significantly shorter in LHI- patients than in LHI+ patients (10 ± 8 mm vs. 21 ± 8 mm; P < 0.05). Conclusions: The LHI observed in the basal septum on short axis LGE may reflect contrast enhancement of the anterior septal perforator arteries. It is important to interpret this septal LHI against knowledge of anatomic structure, to avoid misinterpretations of LGE and prevent misdiagnosis. [ABSTRACT FROM AUTHOR]

The relationship between shot-to-shot sampling rates for dynamic myocardial computed tomography perfusion (CTP) and robustness of CTP-derived myocardial blood flow (CT-MBF) is debatable. We retrospectively investigated the influence of a reduced sampling rate for dynamic CTP on CT-MBF computation and diagnostic performance for detecting myocardial perfusion abnormalities. Pharmacological stress dynamic whole-heart CTP was performed in 120 patients suspected with coronary artery disease. Dynamic CTP data were obtained for 30 continuous heartbeats during the R-peak to R-peak (1RR) interval on electrocardiography. Three additional datasets were created with sub-sampling acquisitions every 2, 3, and 4 heartbeats from the original dataset as interval times of 2RR, 3RR, and 4RR, respectively. CT-MBF was calculated using deconvolution analysis and determined as the mean value of the whole heart (global CT-MBF) and using the 16-segment model (segmental CT-MBF). The diagnostic performance of segmental CT-MBF for detecting perfusion abnormalities was compared to that of cardiac magnetic resonance imaging as the gold standard in 32 of 120 patients. These results were compared among the four CTP datasets. Global CT-MBFs for 1RR, 2RR, 3RR, and 4RR sampling were 1.57 ± 0.34, 1.54 ± 0.36, 1.51 ± 0.37, and 1.41 ± 0.33 mL/g/min, respectively. Areas under the receiver operating characteristic curves of segmental CT-MBF for 1RR, 2RR, 3RR, and 4RR sampling were 0.84, 0.83, 0.79, and 0.76, respectively (1RR versus [vs.] 2RR, non-significant; 1RR vs. 3RR or 4RR, p < 0.05). CT-MBF with 2RR sampling has similar performance with regard to quantification and detecting myocardial perfusion abnormalities as that with 1RR sampling. • CT-MBF with 2RR sampling has similar quantification and diagnostic accuracy as that of 1RR sampling. • CT-MBF with 3RR and greater sampling impair diagnostic accuracy for detecting myocardial perfusion abnormalities. • Reducing the sampling rate of dynamic CTP has influence on CT-MBF calculation especially in normal myocardia. [ABSTRACT FROM AUTHOR]

Abstract Background Direct evidence of inflammatory activity in the atria of patients with atrial fibrillation (AF) is scarce. We assessed the capability of positron-emission tomography/computed tomography (PET/CT) to diagnose AF based on fluorodeoxyglucose (FDG) uptake in the atrial wall. Methods and results Among 8233 patients who underwent FDG-PET/CT as work-up for malignancies, we identified 180 consecutive patients with AF (2.2%). Of those, we selected 137 patients who had fasted >12 h before FDG injection for inclusion in the experimental group (88 men and 49 women; age: 72.7 ± 8.9 years). Controls were 62 age- and sex-matched patients without AF. For visual analysis, we used a 4-point grading system. For quantitative analysis, we used the maximum standard uptake value (SUVmax) in the left (LA) and right atrial (RA) myocardium and the target-to-background ratio (TBR) of SUVmax to blood pool activity. The sensitivity, specificity, and positive-predictive value for detecting AF visually were 54.0%, 95.2%, and 96.1%, respectively; for quantitative analysis, the respective values were 65.7%, 75.8%, and 85.7%. Multivariable analysis of 11 clinical and imaging variables showed significant associations with RA SUVmax (odds ratio [OR]: 14.353, P = 0.026) and LA volume (OR: 1.371, P = 0.0001). The RA TBR was greater in cases with persistent AF than in those with paroxysmal AF (P < 0.0001). Pathological investigation of 4 autopsy hearts confirmed infiltration of extravascular macrophages and lymphocytes in the regions with FDG uptake. Conclusions Higher atrial FDG uptake was associated with AF. PET/CT could be a useful tool for detecting local inflammation in the atria with AF. Highlights • Direct evidence of inflammatory activity in the atria of patients with AF is rare. • Higher atrial FDG uptake is seen in the atria of patients with AF. • Histology reveals immune cell infiltration into atrial regions with FDG uptake. • PET/CT could be a useful tool for detecting local inflammation in the atria with AF. [ABSTRACT FROM AUTHOR]

Background Quantitative assessment of myocardial flow reserve (MFR) by single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is challenging but may facilitate evaluation of multi-vessel coronary artery disease (CAD). Methods We enrolled 153 patients with suspected or known CAD, referred for pharmacological stress MPI. They underwent a 99m Tc-perfusion stress/rest SPECT with an ultrafast cadmium-zinc-telluride (CZT) camera. Dynamic data were acquired and time-activity curves fitted to a 1-tissue compartment analysis with input function. K1 was assigned for stress and rest data. The MFR index (MFR i ) was calculated as K1 stress/K1 at-rest. The findings were validated by invasive coronary angiography in 69 consecutive patients. Results The global MFR i was 1.46 (1.16–1.76), 1.33 (1.12–1.54), and 1.18 (1.01–1.35), for 1-vessel disease (VD), 2-VD, and 3-VD, respectively. In the 3-VD, global MFR i was lower than that in 0-VD (1.63 [1.22–2.04], P < 0.0001) and 1-VD (P = 0.003). Multivariate logistic regression analysis for 3-VD showed significant associations with smoking history (odds ratio [OR]: 4.4 [0.4–8.4]), left ventricular ejection fraction (OR: 61.6 [57.5–66.0]), and global MFR i (OR: 119.6 [111.5–127.7], P = 0.002). A cut-off value of 1.3 yielded 93.3% sensitivity and 75.9% specificity for diagnosing 3-VD. Fractional flow reserve positively correlated with regional MFR i (r = 0.62, P = 0.008), and the SYNTAX score correlated negatively with global MFR i (r = 0.567, P = 0.0003). Conclusion We developed and validated a clinically available method for MFR quantification by dynamic 99m Tc-perfusion SPECT utilizing a CZT camera, which improves the detectability of multi-vessel CAD. [ABSTRACT FROM AUTHOR]

Background: Familial hypercholesterolemia is typically caused by LDL receptor (LDLR) mutations that result in elevated levels of LDL cholesterol (LDL-C). In homozygous FH, the prevalence of aortic valve calcification (AoVC) reaches 100% and is often symptomatic.Objectives: The objective of this study was to investigate the prevalence, extent, and risk-modifiers of AoVC in heterozygous FH (he-FH) that are presently unknown.Methods: Asymptomatic patients with he-FH and 131 non-familial hypercholesterolemia controls underwent CT computed tomography calcium scoring. AoVC was defined as the presence of calcium at the aortic valve leaflets. The extent of AoVC was expressed in Agatston units, as the AoVC-score. We compared the prevalence and extent of AoVC between cases and controls. In addition, we investigated risk modifiers of AoVC, including the presence of LDLR mutations without residual function (LDLR-negative mutations), maximum untreated LDL-cholesterol (maxLDL), LDL-C, blood pressure, and coronary artery calcification (CAC).Results: We included 145 asymptomatic patients with he-FH (93 men; mean age 52 ± 8 years) and 131 non-familial hypercholesterolemia controls. The prevalence (%) and AoVC-score (median, IQR) were higher in he-FH patients than in controls: 41%, 51 (9-117); and 21%, 21 (3-49) (p < 0.001 and p = 0.007). Age, untreated maxLDL, CAC, and diastolic blood pressure were independently associated with AoVC. LDLR-negative mutational he-FH was the strongest predictor of the AoVC-score (OR: 4.81; 95% CI: 2.22 to 10.40; p = <0.001).Conclusions: Compared to controls, he-FH is associated with a high prevalence and a large extent of subclinical AoVC, especially in patients with LDLR-negative mutations, highlighting the critical role of LDL-C metabolism in AoVC etiology. [ABSTRACT FROM AUTHOR]