Prognostic value of right atrial strain in systemic sclerosis based on tissue tracking analysis using cine cardiac magnetic resonance imaging: a retrospective observational study.

Interstitial lung disease and cardiac involvement are common manifestations and prognostic factors of systemic sclerosis. However, it is unclear whether impaired right atrial function associated with interstitial lung disease in systemic sclerosis can be used as a prognostic factor in this patient population. Therefore, this study aimed to investigate the relationship between right atrial function, interstitial lung disease, and prognosis in patients with systemic sclerosis using tissue tracking analysis with cine cardiac magnetic resonance imaging. In this retrospective observational study, a total of 40 patients with systemic sclerosis were enrolled. Tissue tracking analysis was used to obtain time curves of right atrial strain. Reservoir (total strain), conduit (passive strain), and booster (active strain) pump function were calculated, and right atrial strain, interstitial lung disease, and clinical outcomes were examined. An adverse clinical event was defined as all-cause death. Overall, 23 patients had interstitial lung disease (58%). Six patients died during the follow-up (median, 44 months). The total skin score and right ventricular systolic pressure on echocardiography were higher in patients with an event than in those without an event (28 ± 16% vs. 13 ± 13%, P = 0.02; 46.3 ± 10.7 mmHg vs. 36.0 ± 8.5 mmHg, P = 0.01, respectively). Further, right atrial total strain and active strain were significantly lower in patients with an event than in those without an event (14.3 ± 11.3% vs. 25.8 ± 11.4%, P = 0.03; 3.48 ± 2.37 vs. 11.7 ± 6.78, P = 0.007, respectively). Multivariate analysis revealed that active strain was an independent predictor of all-cause death (hazard ratio 0.76, P = 0.029). Kaplan-Meier analysis revealed that the survival rate was significantly higher in patients with right atrial active strain levels above the cutoff 7.4 (P < 0.05). In systemic sclerosis, right atrial booster function was predictive of mortality. Hence, right atrial functional assessment may have incremental prognostic value for patients with systemic sclerosis, leading to better risk stratification.

Prediction of cardiovascular events using myocardial strain ratio derived from 13N-ammonia positron emission tomography.

OBJECTIVES: Myocardial flow reserve (MFR), derived from ammonia N-13 positron emission tomography (NH3-PET), can predict the prognosis of patients with various heart diseases. We aimed to investigate whether myocardial strain ratio (MSR) was useful in predicting MACE and allowed for further risk stratification of cardiovascular events in patients with ischemic heart disease (IHD) in addition to MFR. METHODS: Ninety-five patients underwent NH3-PET because of IHD. MFR was determined as the ratio of hyperemic to resting myocardial blood flow (MBF). MSR was defined as the ratio of strains at stress and rest. The endpoint was major adverse cardiac events (MACE), including all-cause death, acute coronary syndrome, heart failure hospitalization, and revascularization. The ability to predict MACE was assessed using receiver operating characteristic (ROC) analysis, and the predictability of ME was analyzed using Kaplan-Meier analysis. The Cox proportional hazards regression model was used to calculate the hazard ratio (HR) with 95% confidence interval (CI). RESULTS: The ROC curve analysis demonstrated a cutoff of 0.93 for MACE with MSR (sensitivity and specificity of 77% and 71%, respectively). Patients with MSR < 0.93 displayed a significantly higher MACE rate than those with MSR ≥ 0.93 (p = 0.0036). The Cox proportional hazards regression analysis indicated that MSR was an independent marker that could predict MACE in imaging and clinical parameters (HR, 7.32; 95% CI: 1.59-33.7, p = 0.011). CONCLUSIONS: MSR was an independent predictor of MACE and was useful for further risk stratification in IHD. MSR has the potential for a new indicator of revascularization in patients with IHD. KEY POINTS: • We hypothesized that combining myocardial flow reserve (MFR) with the myocardial strain ratio (MSR) obtained by applying the feature-tracking technique to ammonia N-13 PET would make it predictive of major adverse cardiac events (MACE) compared to MFR alone. • MSR was an independent predictor of MACE, allowing for further risk stratification in addition to MFR in patients with ischemic heart disease. • MSR is a potential new indicator of revascularization.

FDG uptake patterns in isolated and systemic cardiac sarcoidosis.

AIMS: We aimed to investigate the pre-treatment characteristics and treatment responses of isolated and systemic cardiac sarcoidosis (ICS and SCS) from FDG-PET/CT studies and to compare the prognoses of the two groups. METHODS: FDG-PET/CT images taken before and after treatment of 31 ICS and 91 SCS patients were analyzed retrospectively. Treatment response and recurrence were determined from the course of FDG-PET/CT. Treatment response and the incidence of both recurrence and major adverse cardiac events (MACE) were assessed in 16 ICS and 35 SCS patients who had been treated for more than 2 years. RESULTS: A focal uptake pattern was more often observed than a focal-on-diffuse uptake pattern in both the ICS (74.2%) and SCS (63.7%) groups. Right ventricular involvement was significantly more frequent in SCS than ICS (44.0% vs. 9.6%, p < .001). SUVmax, cardiac metabolic volume (CMV), and cardiac metabolic activity (CMA) were significantly higher in SCS than ICS (SUVmax, 9.1 ± 4.1 vs. 4.8 ± 2.1; CMV, 118.0 ± 111.3 ml vs. 68.3 ± 94.7 ml; CMA, 541.6 ± 578.7 MBq vs. 265.1 ± 396.0 MBq, p < .001). Treatment responses in the two groups were similar, and complete resolution of cardiac uptake after immunosuppressive treatment was obtained in 62.5% of ICS patients and 77.1% of SCS patients (not significantly different). Likewise, no significant difference was found in the incidence of recurrence (40.0% for ICS, 44.4% for SCS) or MACE (25.0% for ICS, 22.8% for SCS). CONCLUSION: SCS patients had more active and extensive CS lesions than ICS patients before treatment, but the two groups showed similar treatment responses and prognoses.

Abdominal lymphatic pathway in Fontan circulation using non-invasive magnetic resonance lymphangiography.

Lymphatic congestion is known to play an important role in the development of late Fontan complications. This study aimed to (1) develop a gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) contrast three-dimensional heavily T2-weighed MR technique that can detect abnormal lymphatic pathway in the abdomen while simultaneously evaluating hepatocellular carcinoma (HCC) and to (2) propose a new classification of abnormal abdominal lymphatic pathway using a non-invasive method in adults with Fontan circulation. Twenty-seven adults with Fontan circulation who underwent Gd-EOB-DTPA abdominal MR imaging were prospectively enrolled in this study. We proposed MR lymphangiography that suppresses the vascular signal on heavily T2-weighted imaging after EOB contrast. The patients were classified as follows: grade 1 with almost no lymphatic pathway, grade 2 with a lymphatic pathway mainly around the bile duct and liver surface, and grade 3 with a lymphatic pathway mainly around the vertebral body and inferior vena cava. The grade 3 group showed the lowest oxygen saturation level, highest central venous pressure, highest incidence of massive ascites, HCC, and focal nodular hyperplasia. This group also tended to have patients with the oldest age and highest cardiac index; however, the difference was not statistically significant. As for the blood test, the grade 3 group showed the lowest platelet count and serum albumin level and the highest fibrosis-4 index. A novel technique, Gd-EOB-DTPA MR lymphangiography, can detect abnormal abdominal lymphatic pathways in Fontan circulation, which can reflect the severity of failing Fontan.

13 N-ammonia PET-derived right ventricular longitudinal strain and myocardial flow reserve in right coronary artery disease.

PURPOSE: We developed a feature-tracking algorithm for use with electrocardiography-gated high-resolution 13 N-ammonia positron emission tomography (PET) imaging, and we hypothesized it could be used to clarify the association between right ventricular (RV) longitudinal strain (LS) and right coronary artery (RCA) ischemia. The aim of this study was to investigate the association between the reduction of regional myocardial flow reserve (MFR) in RCA territories and PET-derived LS of the RV free wall. METHODS: Ninety-three patients with coronary artery stenosis > 50%, diagnosed by coronary computed tomography angiography, and 10 controls were retrospectively analyzed. RV-LS in the free wall was measured by a feature-tracking technique on the resting and stressed 13 N-ammonia PET images of horizontal long axis slices. The patients were sub-grouped according to regional MFR values at the territories of RCA, left anterior descending artery (LAD), and left circumflex coronary artery (LCx): RCA-MFR < 2.0 [n = 34], RCA-MFR ≥ 2.0 but MFR < 2.0 at LAD or LCx territories [n = 11], and MFR ≥ 2.0 for all territories [n = 48]. Stress and resting RV-LS were compared in each of the four groups. Multiple comparisons of RV-LS among the four groups were performed in the stress and resting state. RESULTS: Decreased stress RV-LS in patients with an RCA-MFR < 2.0 was observed. In the patients with MFR ≥ 2.0 for all territories, the stressed RV-LS was significantly increased compared to that in the resting state. Significantly decreased RV free wall LS during adenosine stress in patients with RCA-MFR < 2.0 was observed in the other three groups. CONCLUSIONS: We measured RV myocardial LS using feature tracking in cine imaging of 13 N-ammonia PET. The results of this study suggest that PET-derived stressed RV-LS is useful for detecting reduced RV myocardial motion due to ischemia in the RCA territory.

Papillary muscle ischemia on high-resolution cine imaging of nitrogen-13 ammonia positron emission tomography: Association with myocardial flow reserve and prognosis in coronary artery disease.

BACKGROUND: The evaluation of papillary muscle (PM) perfusion through existing perfusion imaging, including single-photon emission computed tomography and magnetic resonance imaging, is not possible. Therefore, this study sought to investigate the detection of PM ischemia in coronary artery disease (CAD) using nitrogen-13 (N-13) ammonia positron emission tomography (NH3 PET) and its association with global myocardial flow reserve (MFR) and major adverse cardiac events (MACE). METHODS: Data of adenosine-stress NH3 PET for 263 consecutive patients with known or suspected CAD were retrospectively analyzed. PM ischemia was defined as the absence of PM accumulation under stress conditions and PM presence at rest on high-resolution cine imaging derived from PET-computed tomography scanner with time-of-flight technology. The primary outcome was MACE. RESULTS: Of 263 patients, 30 experienced mean follow-up period of 910 days (MACE), while 31 (11.8%) presented PM ischemia. Compared to patients without PM ischemia, those with PM ischemia reported a significantly lower global MFR and a significantly higher rate of MACE (P < .0001). CONCLUSION: NH3 PET enables the detection of PM ischemia in approximately 10% of patients with known or suspected CAD. PM ischemia is associated with reduced global MFR and is an important sign in predicting prognosis.

13N-ammonia positron emission tomography-derived endocardial strain for the assessment of ischemia using feature-tracking in high-resolution cine imaging.

BACKGROUND: Assessing endocardial strain using a single 13N-ammonia positron emission tomography (PET) scan would be clinically useful, given the association between ischemia and myocardial deformation. However, no software has been developed for strain analysis using PET. We evaluated the clinical potential of feature tracking-derived strain values measured using PET, based on associations with the myocardial flow reserve (MFR). METHODS AND RESULTS: This retrospective study included 95 coronary artery disease patients who underwent myocardial 13N-ammonia PET. Semi-automatic measurements were made using a feature-tracking technique during myocardial cine imaging, and values were calculated using a 16-segment model. Adenosine-stressed global circumferential strain (CS) and global longitudinal strain (LS) values were compared with global MFR values. Stressed and resting global strain values were also compared. Global strain values were significantly lower in 39 patients with abnormal MFRs [< 2.0] than in 56 patients with normal MFRs [≥ 2.0]. The global CS values in the stressed state were significantly decreased than the resting state values in patients with abnormal MFRs. CONCLUSIONS: This study applied endocardial feature-tracking to 13N-ammonia PET, and the results suggested that blood flow and myocardial motility could be clinically assessed in ischemic patients using a single PET scan.

Right ventricular strain and volume analyses through deep learning-based fully automatic segmentation based on radial long-axis reconstruction of short-axis cine magnetic resonance images.

OBJECTIVE: We propose a deep learning-based fully automatic right ventricle (RV) segmentation technique that targets radially reconstructed long-axis (RLA) images of the center of the RV region in routine short axis (SA) cardiovascular magnetic resonance (CMR) images. Accordingly, the purpose of this study is to compare the accuracy of deep learning-based fully automatic segmentation of RLA images with the accuracy of conventional deep learning-based segmentation in SA orientation in terms of the measurements of RV strain parameters. MATERIALS AND METHODS: We compared the accuracies of the above-mentioned methods in RV segmentations and in measuring RV strain parameters by Dice similarity coefficients (DSCs) and correlation coefficients. RESULTS: DSC of RV segmentation of the RLA method exhibited a higher value than those of the conventional SA methods (0.84 vs. 0.61). Correlation coefficient with respect to manual RV strain measurements in the fully automatic RLA were superior to those in SA measurements (0.5-0.7 vs. 0.1-0.2). DISCUSSION: Our proposed RLA realizes accurate fully automatic extraction of the entire RV region from an available CMR cine image without any additional imaging. Our findings overcome the complexity of image analysis in CMR without the limitations of the RV visualization in echocardiography.

First Validation of Myocardial Flow Reserve Derived from Dynamic 99mTc-Sestamibi CZT-SPECT Camera Compared with 13N-Ammonia PET.

13N-ammonia positron emission tomography (NH3-PET) can evaluate myocardial blood flow (MBF) at rest, stress, and myocardial flow reserve (MFR) as well as the ratio of MBF at stress to that at rest. MFR is useful in predicting the prognoses of patients with various heart diseases. Cadmium-zinc-telluride single photon emission computed tomography (CZT-SPECT) enables us to acquire dynamic images of radiotracer kinetics and measure original MBF and MFR using 99mTc-sestamibi. This study aimed to investigate the utility of CZT-SPECT for quantitative assessment of MBF compared to NH3-PET. We validated the correlation of MBF and MFR between CZT-SPECT and NH3-PET. Fourteen patients using one-day rest/stress CZT-SPECT, D-SPECT followed by NH3-PET within 1 month were enrolled and analyzed prospectively. The reproducibility of the MBF and MFR obtained with these two methods was examined using Spearman's correlation coefficient and Bland-Altman plot analysis. The diagnostic value of D-SPECT for abnormal MFR defined using NH3-PET results as MFR < 2.0 was assessed using receiver-operating characteristic (ROC) analysis. The median duration between D-SPECT and NH3-PET was 20 days. Although MBF was overestimated by D-SPECT compared to NH3-PET at high value (mean difference, 0.43 [0.34-0.53]), MBF and MFR were correlated with the two modalities (MBF: r = 0.71, P < 0.0001, MFR: r = 0.60, P < 0.0001). The ROC curve analysis demonstrated a cutoff of 1.6 for detecting abnormal MFR with D-SPECT (sensitivity, 68%; specificity, 91%; AUC, 0.75). MBF and MFR obtained using D-SPECT and NH3-PET had a good correlation, suggesting that the quantitative MFR evaluation by CZT-SPECT may help understand the trend of NH3-PET MFR.

Right Ventricular Extracellular Volume with Dual-Layer Spectral Detector CT: Value in Chronic Thromboembolic Pulmonary Hypertension.

Background Right ventricular (RV) extracellular volumes (ECVs), as a surrogate for histologic fibrosis, have not been sufficiently investigated. Purpose To evaluate and compare RV and left ventricular (LV) ECVs obtained with dual-layer spectral detector CT (DLCT) in chronic thromboembolic pulmonary hypertension (CTEPH) and investigate the clinical importance of RV ECV. Materials and Methods Retrospective analysis was performed on data from 31 patients with CTEPH (17 were not treated with pulmonary endarterectomy [PEA] or balloon pulmonary angioplasty [BPA] and 14 were) and eight control subjects who underwent myocardial delayed enhancement (MDE) DLCT from January 2019 to June 2020. The ECVs in the RV and LV walls were calculated by using iodine density as derived from spectral data pertaining to MDE. Statistical analyses were performed with one-way repeated analysis of variance with the Tukey post hoc test or the Kruskal-Wallis test with the Steel-Dwass test and linear regression analysis. Results The PEA- and BPA-naive group showed significantly higher ECVs than the PEA- or BPA-treated group and control group in the septum (28.2% ± 2.9 vs 24.3% ± 3.6, P = .005), anterior right ventricular insertion point (RVIP) (32.9% ± 4.6 vs 25.3% ± 3.6, P < .001), posterior RVIP (35.2% ± 5.2 vs 27.3% ± 4.2, P < .001), mean RVIP (34.0% ± 4.2 vs 26.3% ± 3.4, P < .001), RV free wall (29.5% ± 3.3 vs 25.9% ± 4.1, P = .036), and mean RV wall (29.1% ± 3.0 vs 26.1% ± 3.1, P = .029). There were no significant differences between the PEA- or BPA-treated group and control subjects in these segments (septum, P = .93; anterior RVIP, P = .38; posterior RVIP, P = .52; mean RVIP, P = .36; RV free wall, P = .97; and mean RV, P = .33). There were significant correlations between ECV and mean pulmonary artery pressure (PAP) or brain natriuretic peptide (BNP) in the mean RVIP (mean PAP: R = 0.66, P < .001; BNP: R = 0.44, P = .014) and the mean RV (mean PAP: R = 0.49, P = .005; BNP: R = 0.44, P = .013). Conclusion Right ventricular and right ventricular insertion point extracellular volumes could be noninvasive surrogate markers of disease severity and reverse tissue remodeling in chronic thromboembolic pulmonary hypertension. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Sandfort and Bluemke in this issue.

Prognosis and recurrence in cardiac sarcoidosis: Serial assessment of BMIPP SPECT and FDG-PET.

BACKGROUND: We analyzed 18F-Fludeoxyglucose positron emission tomography (FDG-PET) and 123I-betamethyl-p-iodophenyl-pentadecanoic acid (BMIPP) single-photon emission computed tomography (SPECT) performed for cardiac sarcoidosis (CS) patients taking prednisolone, identified recurrence by FDG-PET, and investigated BMIPP as a recurrence and prognostic factor in CS. METHODS AND RESULTS: CS patients who underwent BMIPP and FDG-PET within 2 months were enrolled. The recurrence-free group included patients with standardized uptake value (SUVmax) < 4 in the myocardium consecutively for ≥ 2 years. The total BMIPP SPECT defect score (BDS) was used to estimate myocardial damage. The predictability of the initial BDS and SUVmax for major adverse cardiac events (MACE) was analyzed using Kaplan-Meier analysis. Overall, 73 patients and 250 BMIPP and FDG-PET sets were analyzed retrospectively (mean follow-up, 3.5 years). The BDS was significantly greater for the recurrence group (N = 21) vs recurrence-free group (20 ± 13 vs 14 ± 12, P = 0.041). Patients with BDS ≥16 had a significantly higher MACE rate than patients with BDS < 16 (log-rank test, P = 0.016). However, MACE occurrence was comparable between patients with SUVmax ≥ 4 and < 4. CONCLUSIONS: BDS is a predictive marker of recurrence and MACE. SUV is not related to MACE. Recurrence, defined by prednisolone treatment-induced SUV variability, was observed in approximately 30% of CS patients.

New transluminal attenuation gradient derived from dynamic coronary CT angiography: diagnostic ability of ischemia detected by 13N-ammonia PET.

Coronary computed tomography angiography (CCTA) has low specificity for detecting significant functional coronary stenosis. We developed a new transluminal attenuation gradient (TAG)-derived dynamic CCTA with dose modulation, and we investigated its diagnostic performance for myocardial ischemia depicted by 13N-ammonia positron emission tomography (PET). Data from 48 consecutive patients who had undergone both dynamic CCTA and 13N-ammonia PET were retrospectively analyzed. Dynamic CCTA was continuously performed in mid-diastole for five cardiac cycles with prospective electrocardiography gating after a 10-s contrast medium injection. One scan of the dynamic CCTA was performed as a boost scan for conventional CCTA at the peak phase of the ascending aorta. Absolute TAG values at five phases around the boost scan were calculated. The dynamic TAG index (DTI) was defined as the ratio of the maximum absolute TAG to the standard deviation of five TAG values. We categorized the coronary territories as non-ischemia or ischemia based on the 13N-ammonia PET results. A receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff of the DTI for identifying ischemia. The DTI was significantly higher for ischemia compared to non-ischemia (8.8 ± 3.9 vs. 4.6 ± 2.0, p < 0.01). The ROC analysis revealed 5.60 as the optimal DTI cutoff to detect ischemia, with an area under the curve of 0.87, 85.7% sensitivity, and 76.2% specificity. TAG provided no additional diagnostic value for the detection of ischemia. We propose the DTI derived from dynamic CCTA as a novel coronary flow index. The DTI is a valid technique for detecting functional coronary stenosis.

Aortic Vorticity, Helicity, and Aortopathy in Adult Patients with Tetralogy of Fallot: Pilot Study Using Four-Dimensional Flow Magnetic Resonance Images.

To employ quantitative analysis in the vorticity and helicity of the aortic root and the ascending aorta (AAo) in adults with tetralogy of Fallot (TOF), and to evaluate aortopathy and the relevant factors. Prospectively, 51 consecutive adults with TOF underwent 4 dimensional flow magnetic resonance imaging study for the assessment of vorticity and helicity of the aortic root and AAo, wall shear stress (WSS), viscous energy loss (EL), and the left ventricular outflow tract - aortic root (LVOT-Ao) angle. Patients were divided into the two groups: dilated aortic root and/or AAo (indexed diameter > 25 mm/cm2), Group A (15 patients); non-dilated aortic patients, Group B (36 patients). Ten age-matched controls were also enrolled. Group A showed more acute LVOT-Ao angle, higher incidence of aortic regurgitation, and initial anatomy of pulmonary atresia, compared to Group B (P < 0.0001, 0.02, 0.043). Group A showed greater clockwise vorticity at the level of Valsalva, AAo, and proximal arch, sagittal vorticity, AAo helicity, WSS, and EL than in Group B (P < 0.001, < 0.001, < 0.001, 0.045, 0.049, 0.02, 0.026). More acute LVOT-Ao angle correlated with the diameter of the aortic root and AAo, AAo vorticity, helicity, WSS, and EL (P = 0.004, 0.023, 0.045, 0.004, 0.0004, 0.017). On a univariate logistic analysis, more acute LVOT-Ao angle, AAo vorticity, AAo helicity, and maximum WSS were relevant factors of AAo dilatation (P = 0.02, 0.02, 0.045, 0.03, 0.046). On a multivariate logistic analysis, more acute LVOT-Ao angle was the most important factor of AAo dilatation (odds ratio 0.66, 95% CI 0.46-0.95, P < 0.024). TOF adults presenting dilated AAo have greater vorticity, helicity, and acute LVOT-Ao angle. Flow eccentricity and these flow hemodynamic parameters may be adjunctive predictions of aortopathy in this population.

Radiation dose for 320-row dose-modulated dynamic coronary CT angiography.

OBJECTIVES: The area detector 320-row CT scanner, which can cover the whole heart in one rotation, can aid in reducing radiation exposure during electrocardiography (ECG)-gated coronary CT angiography (CCTA). Recently, researchers have proposed dose-modulated dynamic CCTA with a 320-row scanner for the detection of functional myocardial ischemia. In the present study, we compared and validated the radiation dose of this method with that of the standard CCTA method and the latest diagnostic reference levels (DRLs). MATERIALS AND METHODS: The study included a total of 164 consecutive patients with suspected or known coronary artery disease (CAD) who underwent CCTA with a 320-row scanner. The patients were randomly divided into dynamic and standard CCTA groups, and the CT dose index (CTDIvol) and dose length product (DLP) calculated by the CT system were compared between the two protocols and with the latest DRL. RESULTS: Standard and dynamic CCTA scans were performed in 77 and 87 patients, respectively. CTDIvol was significantly higher for standard CCTA than for dynamic CCTA (41 ± 35 mGy vs. 22 ± 7 mGy, p = 0.0014). DLP was also significantly higher for standard CCTA than for dynamic CCTA (864 ± 702 mGy × cm vs. 434 ± 106 mGy × cm, p < .0001). For standard scans, CTDIvol and DLP exceeded the 2020 DRL in Japan in 16% (12/77) and 17% (13/77) of cases, respectively. In contrast, rates for the dynamic scan were only 1% (1/87) for CTDIvol and 0% (0/87) for DLP. CONCLUSION: The dose of radiation exposure during dynamic CCTA with a 320-row scanner does not exceed that of standard CCTA and is sufficient to meet the latest DRL. Thus, our results suggest that the method is safe from the perspective of radiation exposure.

Association between myocardial hypoxia and fibrosis in hypertrophic cardiomyopathy: analysis by T2* BOLD and T1 mapping MRI.

OBJECTIVES: We assessed whether an association exists between myocardial oxygenation and myocardial fibrosis in patients with hypertrophic cardiomyopathy (HCM), using blood-oxygen-level-dependent (BOLD) T2* cardiac magnetic resonance imaging (T2*-CMR) and T1 mapping. METHODS: T1 mapping and T2*-CMR data were collected from 55 HCM patients using a 3-T MR and were prospectively analyzed. T2*-CMR was conducted using the black blood, breath-hold, multi-echo, and gradient echo sequence. Over 10 min, inhalation of oxygen at the flow rate of 10 L/min, T2* for mid-septum was measured following room-air and oxygen inhalation, and ΔT2* ratio (T2*oxy-T2*air/T2*air, %) was calculated. During pre- and post-gadolinium enhancement, native T1 (ms) and extracellular volume fractions (ECV, %) were calculated at sites same as the T2* measurement. Hypoxia was defined as the segment with an absolute value of the ΔT2* ratio ≥ 10%. RESULTS: ΔT2* ratio was significantly higher for segments with native T1 ≥ 1290 ms than those with native T1 < 1290 ms (21 ± 32% vs. 8 ± 6%, p = 0.005). ΔT2* ratio was also significantly higher for segments with ECV ≥ 28% than those with ECV < 28% (21 ± 32% vs. 8 ± 8%, p = 0.0003). ROC curve analysis revealed that ΔT2* ratio could detect segments with native T1 ≥ 1290 ms and ECV ≥ 28% and c-statistics of 0.72 and 0.79. According to the multivariate logistic regression analysis results, ECV is an independent factor in hypoxia (odds ratio, 1.47; 95% confidence interval, 1.02-2.13; p < 0.05). CONCLUSIONS: Analysis of BOLD T2*-CMR and T1 mapping revealed that ECV is strongly associated with ΔT2* ratio, suggesting that the onset of myocardial fibrosis is related to hypoxia in HCM patients. TRIAL REGISTRATION: Our study was approved by the ethics committee of our institute (#4036, registered on 21 July 2016) KEY POINTS: • Analysis of ΔT2* ratio and ECV with BOLD-T2* and T1 mapping revealed a strong association between myocardial fibrosis and hypoxia in HCM patients.

Patient Based Bull's Eye Map Display of Coronary Artery and Ventricles From Coronary Computed Tomography Angiography.

Coronary computed tomography angiography is widely used in clinical practice. Although 3-dimensional (D) volume rendering is useful for interpretation of coronary path and territory, 2D output is common for image interpretation. Most picture archiving and communication system is incapable of manipulating 3D due to insufficient graphic specification. Thus, 2D bull's eye map display is frequently used in cardiac imaging. We developed a bull's eye map which emulated the anatomical information of individual coronary path and dominancy.

Low Radiation Dose and High Image Quality of 320-Row Coronary Computed Tomography Angiography Using a Small Dose of Contrast Medium and Refined Scan Timing Prediction.

OBJECTIVE: The aim of the study was to investigate the feasibility of coronary computed tomography (CT) angiography with a low kilovoltage peak scan and a refined scan timing prediction using a small contrast medium (CM) dose. METHODS: In protocol A, 120-kVp scanning and a standard CM dose were used. The scan timing was fixed. In protocol B, 80 kVp and a 60% CM dose were used. The scan timing was determined according to the interval from the CM arrival to the peak time in the ascending aorta. We measured the CT number and recorded the radiation dose. RESULTS: Higher CT numbers were observed in the left circumflex (proximal, P = 0.0235; middle, P = 0.0007; distal, P < 0.0001) in protocol B compared with protocol A. The radiation dose in protocol B was significantly lower than in protocol A (2.2 ± 0.9 vs 4.3 ± 1.7 mSv). CONCLUSIONS: Low-contrast, low-radiation dose, high-image quality coronary CT angiography can be performed with low kilovoltage peak scanning and a refined scan timing prediction.

Liver Strain Using Feature Tracking of Cine Cardiac Magnetic Resonance Imaging: Assessment of Liver Dysfunction in Patients with Fontan Circulation and Tetralogy of Fallot.

We propose a novel method to quantify pulsatile liver deformation using the feature tracking method of cardiac cine magnetic resonance imaging (MRI) and investigate its association with liver dysfunction in long-term postoperative patients after Fontan and intracardiac repair for the tetralogy of Fallot (TOF). Standard cine MRI which was previously performed for cardiac evaluation of 85 patients who underwent Fontan operation (mean age, 22.9 years), 43 patients with TOF (mean age, 34.6 years), and 32 healthy controls (mean age, 42.3 years) were retrospectively analyzed. Pulsatile liver deformation in the craniocaudal direction was calculated using the feature tracking method of cardiac cine imaging derived from cine-balanced turbo field-echo sequences performed on a 1.5 Tesla MR scanner, and was defined as liver strain. The liver strain was compared across the three patient groups using one-way analysis of variance. Liver dysfunction by a liver strain were compared using the Mann-Whitney U test. Liver strain for patients who underwent Fontan operation and TOF patients was significantly lower than controls (Fontan, 13.3 ± 6.5%; TOF, 15.0 ± 11.2%; controls, 23.1 ± 10.2%, p < 0.0001). In Fontan and TOF patients, MELD score was significantly greater for patients with a liver strain < 15% than those with values > 15% (5.9 ± 5.8 vs. 2.9 ± 2.9, p < 0.001). Lower liver strain values were found in adolescent and adult patients after Fontan operation and TOF, and correlates with the severity of liver injury, expressed as MELD score. Our method can evaluate hepatic function in adult congenital heart disease, together with the assessment of cardiac function.

Potential Value of Native T1 Mapping in Symptomatic Adults with Congenital Heart Disease: A Preliminary Study of 3.0 Tesla Cardiac Magnetic Resonance Imaging.

The native T1 value at 3.0 Tesla is a sensitive marker of diffuse myocardial damage. We evaluated the clinical usefulness of native T1 mapping in symptomatic adults with congenital heart disease (CHD), particularly in the systemic right ventricle (RV). Prospectively, 45 consecutive symptomatic adults with CHD were enrolled: 20 with systemic RV and 25 with tetralogy of Fallot underwent cardiac magnetic resonance (CMR) imaging at 3.0 Tesla. The Modified Look-Locker Inversion recovery sequence was used for T1 mapping. Cardiovascular events in the systemic RV were defined as heart failure and tachyarrhythmia. Brain natriuretic peptide (BNP) and indexed systemic ventricular end-diastolic volume were significantly higher in the systemic RV group. The native T1 value and extracellular volume (ECV) of the septal and lateral walls were higher in the systemic RV group, suggesting high impairment of the myocardium in the systemic RV group. There was a strong correlation between the native T1 value and ECV of the septum (r = 0.58, P = 0.03) and lateral wall (r = 0.56, P = 0.046) in the systemic RV group. Seven patients with systemic RV had cardiovascular events. In univariate logistic regression analysis, BNP and native T1 values of the insertion point were important for predicting cardiovascular events. The native T1 value at 3.0 Tesla may be a sensitive, contrast-free, and non-invasive adjunct marker of myocardial damage in CHD and predictive of cardiovascular events in the systemic RV.

Stroke volume ratio derived from magnetic resonance imaging as an indicator of interventricular dyssynchrony predicts future cardiac event in patients with biventricular Fontan circulation.

The prognostic factors in patients with biventricular heart who underwent Fontan surgery remain unclear. This study wanted to assess the hypothesis that interventricular dyssynchrony evaluated by cardiac magnetic resonance imaging (MRI) can predict future cardiac events in patients with biventricular heart who have undergone Fontan surgery. We prospectively enrolled consecutive patients with biventricular Fontan circulation from 2003 to 2016, and performed protocolized cardiac MRI. We determined the stroke volume ratio (SVr) using the following formula to assess interventricular dyssynchrony: (stroke volume (SV) of the two whole ventricles)/(SV of the right ventricle + SV of the left ventricle), by tracing cine MRI data. If interventricular dyssynchrony existed, blood flowed and returned to each ventricle through the ventricular septal defect; therefore, the SVr in this instance should be less than 1.0. We enrolled 40 patients. SVr ranged from 0.81 to 1.0 (median 0.95). Low SVr (< 0.95) was associated with worse New York Heart Association functional class, longer QRS duration, right bundle branch block, low biventricular indexed stroke volume, and low biventricular ejection fraction. During the follow-up period (median 53.5 months), 10 cardiac events occurred (six cases of acute exacerbation of heart failure, three cases of supraventricular tachycardia, and one case of exacerbation of protein-losing enteropathy). Univariate analysis showed four clinical predictors: SVr < 0.95 [hazard ratio (HR) 9.3, 95% confidential interval (CI) 1.7-171.5]; biventricular ejection fraction < 0.45 (HR 9.4, 95% CI 2.2-65.3); left ventricular indexed end-diastolic volume > 73 mL/m2 (HR 4.5, 95% CI 1.1-15.7); and the presence of the aorta directly arising from the right ventricular conus (HR 5.8, 95% CI 1.1-106). SVr derived from MRI can predict future cardiac events in Fontan patients with biventricular hearts.