Impact of Myocardial Viability on Long-term Outcomes after Surgical Revascularization.

BACKGROUND: This study was conducted to evaluate whether myocardial viability assessed with cardiac magnetic resonance (CMR) affected long-term clinical outcomes after coronary artery bypass grafting (CABG) in patients with ischemic cardiomyopathy (ICMP). METHODS: Preoperative CMR with late gadolinium enhancement (LGE) was performed in 103 patients (64.9 ± 10.1 years, male:female = 82:21) with 3-vessel disease and left ventricular dysfunction (ejection fraction ≤ 0.35). Transmural extent of LGE was evaluated on a 16-segment model, and transmurality was graded on a 5-point scale: grades-0, absence; 1, 1 to 25%; 2, 26 to 50%; 3, 51 to 75%; 4, 76 to 100%. Median follow-up duration was 65.5 months (interquartile range = 27.5-95.3 months). Primary endpoint was the composite of all-cause mortality or hospitalization for congestive heart failure. RESULTS: Operative mortality was 1.9%. During the follow-up, all-cause mortality and readmission for congestive heart failure occurred in 29 and 8 patients, respectively. The cumulative incidence of the primary endpoint was 31.3 and 46.8% at 5 and 10 years, respectively. Multivariable analysis demonstrated that the number of segments with LGE grade 4 was a significant risk factor (hazard ratio 1.42, 95% confidence interval 1.10-1.83, p = 0.007) for the primary endpoint among the variables assessed by CMR. Other risk factors included age, dialysis, chronic obstructive pulmonary disease, and EuroSCORE II. CONCLUSION: The number of myocardial segments with transmurality of LGE >75% might be a prognostic factor associated with the composite of all-cause mortality or hospitalization for congestive heart failure after CABG in patients with 3-vessel disease and ICMP.

Performance of 1-mm non-gated low-dose chest computed tomography using deep learning-based noise reduction for coronary artery calcium scoring.

OBJECTIVE: To investigate performance of 1-mm, sharp kernel, low-dose chest computed tomography (LDCT) for coronary artery calcium scoring (CACS) using deep learning (DL)-based denoising technique. METHODS: This retrospective, intra-individual comparative study consisted of four image datasets of 131 participants who underwent LDCT and calcium CT on the same day between January and February 2020; 1-mm LDCT with DL, 1-mm LDCT with iterative reconstruction (IR), 3-mm LDCT, and calcium CT. CACS from calcium CT were considered as reference and CACS were categorized as 0, 1-10, 11-100, 101-400, and > 400. We compared CACS from LDCTs with that from calcium CT. RESULTS: Mean CACS was 104.8 ± 249.1 and proportion of positive CACS was 45% (59/131). CACS from LDCT images tended to be underestimated than those from calcium CT: 1-mm LDCT with DL (93.5 ± 249.6, p = 0.002), 1-mm LDCT with IR (94.7 ± 249.9, p < 0.001), and 3-mm LDCT (90.3 ± 245.3, p = 0.004). All LDCT datasets showed excellent agreement with calcium CT: intraclass correlation coefficient (ICC) = 0.961 (95% confidence interval (CI), 0.945-0.972) for DL, 0.969 (95% CI, 0.956-0.978) for IR, and 0.952 (95% CI, 0.932-0.966) for 3-mm LDCT; weighted kappa for CACS classification, 0.930 (95% CI, 0.893-0.966) for 1-mm LDCT with DL, 0.908 (95% CI, 0.866-0.950) for 1-mm LDCT with IR, and 0.846 (95% CI, 0.780-0.912) for 3-mm LDCT. The accuracy of CACS classification of 1-mm LDCT with DL (90%) tended to be better than 1-mm LDCT with IR (87%) and 3-mm LDCT (84.7%) (p = 0.10). CONCLUSION: DL-based noise reduction algorithm can offer reliable calcium scores in 1-mm LDCT reconstructed with sharp kernel. KEY POINTS: • Deep learning (DL)-based noise reduction enables calcium scoring at 1-mm, sharp kernel reconstructed low-dose chest CT (LDCT). • Both iterative reconstruction and DL-based noise reduction underestimated calcium score, but agreement were excellent with those from calcium CT. • Accuracy of categorical classification of calcium scoring tended to be highest in 1-mm LDCT with DL compared to 1-mm LDCT with IR and 3-mm LDCT (90%, 87%, and 84.7%, p = 0.10).

Results after Tricuspid Valve Surgery for Preserved and Dysfunctional Right Ventricle.

BACKGROUND: This study aimed to compare long-term outcomes after tricuspid valve (TV) repair (TVr) with those after TV replacement (TVR) by adjusting the right ventricular (RV) volume and function. METHODS: We enrolled 147 patients who underwent TVr (n = 78) and TVR (n = 69) for grade 3 or 4 tricuspid regurgitation and had preoperative cardiac magnetic resonance data. Long-term clinical outcomes were compared between the two groups using inverse probability treatment weighting (IPTW) to adjust for differences in preoperative characteristics between the two groups. Subgroup analyses were performed in patients with preserved and dysfunctional RV (ejection fraction < 50%). RESULTS: There were no significant differences in operative mortality or postoperative complications between the two groups before and after the IPTW adjustment. Five- and 10-year overall survival rates were 84.2 and 67.1%, respectively. Five- and 10-year cumulative incidences of TV-related events (TVREs) were 33.1 and 55.6%, respectively. There were no significant differences in overall survival and cumulative incidence of TVREs after IPTW adjustment (p = 0.236 and p = 0.989, respectively). The risk-adjusted overall survival was marginally higher in the TVr group of patients with preserved RV function (p = 0.054), while no such significant difference was found between the two groups of patients with dysfunctional RV (p = 0.513). CONCLUSION: Adjusted long-term clinical outcomes after TVr and TVR were comparable. TVr might be beneficial for patients with preserved RV function in terms of long-term survival; however, this benefit might disappear in patients with RV dysfunction.

Phantom-based correction for standardization of myocardial native T1 and extracellular volume fraction in healthy subjects at 3-Tesla cardiac magnetic resonance imaging.

OBJECTIVES: To investigate the effect of the phantom-based correction method for standardizing myocardial native T1 and extracellular volume fraction (ECV) in healthy subjects. METHODS: Seventy-one healthy asymptomatic adult (≥ 20 years) volunteers of five different age groups (34 men and 37 women, 45.5 ± 15.5 years) were prospectively enrolled in three academic hospitals. Cardiac MRI including Modified Look - Locker Inversion recovery T1 mapping sequence was performed using a 3-Tesla system with a different type of scanner for each hospital. Native T1 and ECV were measured in the short-axis T1 map and analyzed for mean values of the 16 entire segments. The myocardial T1 value of each subject was corrected based on the site-specific equation derived from the T1 Mapping and ECV Standardization phantom. The global native T1 and ECV were compared between institutions before and after phantom-based correction, and the variation in native T1 and ECV among institutions was assessed using a coefficient of variation (CoV). RESULTS: The global native T1 value significantly differed between the institutions (1198.7 ± 32.1 ms, institution A; 1217.7 ± 39.9 ms, institution B; 1232.7 ± 31.1 ms, institution C; p = 0.002), but the mean ECV did not (26.6-27.5%, p = 0.355). After phantom-based correction, the global native T1 and ECV were 1289.7 ± 32.4 ms and 25.0 ± 2.7%, respectively, and CoV for native T1 between the three institutions decreased from 3.0 to 2.5%. The corrected native T1 value did not significantly differ between institutions (1284.5 ± 31.5 ms, institution A; 1296.5 ± 39.1 ms, institution B; 1291.3 ± 29.3 ms, institution C; p = 0.440), and neither did the ECV (24.4-25.9%, p = 0.078). CONCLUSIONS: The phantom-based correction method can provide standardized reference T1 values in healthy subjects. KEY POINTS: • After phantom-based correction, the global native T1 of 16 entire myocardial segments on 3-T cardiac MRI is 1289.4 ± 32.4 ms, and the extracellular volume fraction was 25.0 ± 2.7% for healthy subjects. • After phantom - based correction was applied, the differences in the global native T1 among institutions became insignificant, and the CoV also decreased from 3.0 to 2.5%.

Compositional Study of Phospholipids from the Dried Big Head and Opossum Shrimp, Mussel, and Sea Cucumber Using 31P NMR Spectroscopy: Content and Fatty Acid Composition of Plasmalogen.

Herein, we present a qualitative and quantitative analysis of the compositions of plasmalogens and phospholipids (PLs) in dried big head shrimp (Solenocera melantho), opossum shrimp (Neomysis awatschensis), mussel (Mytilus galloprovincialis), and sea cucumber (Apostichopus japonicus). We also analyze the fatty acid composition of the extracted lipids, phosphatidyl choline (PtdCho), and plasmalogen choline (PlsCho) from each sample. In big head shrimp, opossum shrimp, and mussel, phosphatidyl choline (PtdCho) was the most abundant PL at 1677.9, 1603, and 1661.6 mg/100 g of dried sample, respectively, whereas the most abundant PL in sea cucumber was PlsCho (206.9 mg/100 g of dried sample). In all four samples, plasmalogen ethanolamine (PlsEtn) was higher than phosphatidyl ethanolamine (PtdEtn). The content (mg/100 g of dried sample) of PlsCho was highest in mussel (379.0), and it was higher in big head shrimp (262.3) and opossum shrimp (245.6) than sea cucumber (206.9). The contents (mg/100 g of dried sample) of PlsEtn were in the order of mussel (675.4) > big head shrimp (629.5) > opossum shrimp (217.9) > sea cucumber (51.5). For analyzing the fatty acids at the sn-2 position of PlsCho, the consecutive treatment with phospholipase A1, solid phase extraction, thin-layer chromatography (TLC), and GC-FID were applied. The most abundant fatty acid was eicosapentaenoic acid (EPA, C20:5, n-3) in big head shrimp and sea cucumber, palmitoleic acid (C16:1, n-7) in opossum shrimp, and docosadienoic acid (C22:2, n-6) in mussel.

Kinesin-13, a Motor Protein, is Regulated by Polo-like Kinase in Giardia lamblia.

Kinesin-13 (Kin-13), a depolymerizer of microtubule (MT), has been known to affect the length of Giardia. Giardia Kin-13 (GlKin-13) was localized to axoneme, flagellar tips, and centrosomes, where phosphorylated forms of Giardia polo-like kinase (GlPLK) were distributed. We observed the interaction between GlKin-13 and GlPLK via co-immunoprecipitation using transgenic Giardia cells expressing Myc-tagged GlKin-13, hemagglutinin-tagged GlPLK, and in vitro-synthesized GlKin-13 and GlPLK proteins. In vitro-synthesized GlPLK was demonstrated to auto-phosphorylate and phosphorylate GlKin-13 upon incubation with [γ-32P]ATP. Morpholino-mediated depletion of both GlKin-13 and GlPLK caused an extension of flagella and a decreased volume of median bodies in Giardia trophozoites. Our results suggest that GlPLK plays a pertinent role in formation of flagella and median bodies by modulating MT depolymerizing activity of GlKin-13.

Automatic prediction of left cardiac chamber enlargement from chest radiographs using convolutional neural network.

OBJECTIVE: To develop deep learning-based cardiac chamber enlargement-detection algorithms for left atrial (DLCE-LAE) and ventricular enlargement (DLCE-LVE), on chest radiographs METHODS: For training and internal validation of DLCE-LAE and -LVE, 5,045 chest radiographs (CRs; 2,463 normal and 2,393 LAE) and 1,012 CRs (456 normal and 456 LVE) matched with the same-day echocardiography were collected, respectively. External validation was performed using 107 temporally independent CRs. Reader performance test was conducted using the external validation dataset by five cardiothoracic radiologists without and with the results of DLCE. Classification performance of DLCE was evaluated and compared with those of the readers and conventional radiographic features, including cardiothoracic ratio, carinal angle, and double contour. In addition, DLCE-LAE was tested on 5,277 CRs from a healthcare screening program cohort. RESULTS: DLCE-LAE showed areas under the receiver operating characteristics curve (AUROCs) of 0.858 on external validation. On reader performance test, DLCE-LAE showed better results than pooled radiologists (AUROC 0.858 vs. 0.651; p < .001) and significantly increased their performance when used as a second reader (AUROC 0.651 vs. 0.722; p < .001). DLCE-LAE also showed a significantly higher AUROC than conventional radiographic findings (AUROC 0.858 vs. 0.535-0.706; all ps < .01). In the healthcare screening cohort, DLCE-LAE successfully detected 71.0% (142/200) CRs with moderate-to-severe LAE (93.5% [29/31] of severe cases), while yielding 11.8% (492/4,184) false-positive rate. DLCE-LVE showed AUROCs of 0.966 and 0.594 on internal and external validation, respectively. CONCLUSION: DLCE-LAE outperformed and improved cardiothoracic radiologists' performance in detecting LAE and showed promise in screening individuals with moderate-to-severe LAE in a healthcare screening cohort. KEY POINTS: • Our deep learning algorithm outperformed cardiothoracic radiologists in detecting left atrial enlargement on chest radiographs. • Cardiothoracic radiologists improved their performance in detecting left atrial enlargement when aided by the algorithm. • On a healthcare-screening cohort, our algorithm detected 71.0% (142/200) radiographs with moderate-to-severe left atrial enlargement while yielding 11.8% (492/4,184) false-positive rate.

Myocardial structural and functional changes in patients with liver cirrhosis awaiting liver transplantation: a comprehensive cardiovascular magnetic resonance and echocardiographic study.

BACKGROUND: Cardiac dysfunction is increasingly recognized in patients with liver cirrhosis. Nevertheless, the presence or absence of structural alterations such as diffuse myocardial fibrosis remains unclear. We aimed to investigate myocardial structural changes in cirrhosis, and explore left ventricular (LV) structural and functional changes induced by liver transplantation. METHODS: This study included 33 cirrhosis patients listed for transplantation and 20 healthy controls. Patients underwent speckle-tracking echocardiography and cardiovascular magnetic resonance (CMR) with extracellular volume fraction (ECV) quantification at baseline (n = 33) and 1 year after transplantation (n = 19). RESULTS: CMR-based LV ejection fraction (CMRLV-EF) and echocardiographic LV global longitudinal strain (LV-GLS) demonstrated hyper-contractile LV in cirrhosis patients (CMRLV-EF: 67.8 ± 6.9% in cirrhosis vs 63.4 ± 6.4% in healthy controls, P = 0.027; echocardiographic GLS: - 24.2 ± 2.7% in cirrhosis vs - 18.6 ± 2.2% in healthy controls, P < 0.001). No significant differences in LV size, wall thickness, mass index, and diastolic function between cirrhosis patients and healthy controls were seen (all P > 0.1). Only one of the cirrhosis patients showed late gadolinium enhancement. However, cirrhosis patients showed a higher ECV (31.6 ± 5.1% vs 25.4 ± 1.9%, P < 0.001) than healthy controls. ECV showed a positive correlation with Child-Pugh score (r = 0.564, P = 0.001). Electrocardiogram-based corrected QT interval was prolonged in cirrhosis (P < 0.001). One-year post-transplantation, echocardiographic LV-GLS (from - 24.9 ± 2.4% to - 20.6 ± 3.4%, P < 0.001) and ECV (from 30.9 ± 4.5% to 25.4 ± 2.6%, P = 0.001) moved to the normal ranges. Corrected QT interval decreased after transplantation (from 475 ± 41 to 429 ± 30 msec, P = 0.001). CONCLUSIONS: Myocardial extracellular volume expansion with augmented resting LV systolic function was characteristic of cirrhotic cardiomyopathy, which normalizes 1-year post-transplantation. Thus, myocardial extracellular expansion represents a structural component of myocardial changes in cirrhosis.

Increased Innate Lymphoid Cell 3 and IL-17 Production in Mouse Lamina Propria Stimulated with Giardia lamblia.

Innate lymphoid cells (ILCs) are key players during an immune response at the mucosal surfaces, such as lung, skin, and gastrointestinal tract. Giardia lamblia is an extracellular protozoan pathogen that inhabits the human small intestine. In this study, ILCs prepared from the lamina propria of mouse small intestine were incubated with G. lamblia trophozoites. Transcriptional changes in G. lamblia-exposed ILCs resulted in identification of activation of several immune pathways. Secretion of interleukin (IL)-17A, IL-17F, IL-1ß, and interferon-γ was increased, whereas levels of IL-13, IL-5, and IL22, was maintained or reduced upon exposure to G. lamblia. Goup 3 ILC (ILC3) was found to be dominant amongst the ILCs, and increased significantly upon co-cultivation with G. lamblia trophozoites. Oral inoculation of G. lamblia trophozoites into mice resulted in their presence in the small intestine, of which, the highest number of parasites was detected at the 5 days-post infection. Increased ILC3 was observed amongst the ILC population at the 5 days-post infection. These findings indicate that ILC3 from the lamina propria secretes IL-17 in response to G. lamblia, leading to the intestinal pathology observed in giardiasis.

Production of Inflammatory Cytokines and Nitric Oxide by Human Mast Cells Incubated with Toxoplasma gondii Lysate.

The roles of mast cells in allergic diseases and helminth infections are well known. However, the roles of mast cells in T. gondii infection is poorly understood. This study was focused on the production of pro-inflammatory cytokines (TNF-α, IL-4), chemokines (CXCL8, MCP-1) and nitric oxide (NO) by mast cells in response to soluble lysate of T. gondii tachyzoites. Production of CXCL8 (IL-8), MCP-1, TNF-α and IL-4 were measured by RT-PCR and ELISA. Western blot were used for detection of CXCR-1 and CXCR2. Our results showed that T. gondii lysates triggered mast cells to release CXCL8, MCP-1, TNF-α, IL-4 and to produce NO. This suggests that mast cells play an important role in inflammatory responses to T. gondii.

Ferumoxytol enhanced black-blood cardiovascular magnetic resonance imaging.

BACKGROUND: Bright-blood and black-blood cardiovascular magnetic resonance (CMR) techniques are frequently employed together during a clinical exam because of their complementary features. While valuable, existing black-blood CMR approaches are flow dependent and prone to failure. We aim to assess the effectiveness and reliability of ferumoxytol enhanced (FE) Half-Fourier Single-shot Turbo Spin-echo (HASTE) imaging without magnetization preparation pulses to yield uniform intra-luminal blood signal suppression by comparing FE-HASTE with pre-ferumoxytol HASTE imaging. METHODS: This study was IRB-approved and HIPAA compliant. Consecutive patients who were referred for FE-CMR between June 2013 and February 2017 were enrolled. Qualitative image scores reflecting the degree and reliability of blood signal suppression were based on a 3-point Likert scale, with 3 reflecting perfect suppression. For quantitative evaluation, homogeneity indices (defined as standard deviation of the left atrial signal intensity) and signal-to-noise ratios (SNR) for vascular lumens and cardiac chambers were measured. RESULTS: Of the 340 unique patients who underwent FE-CMR, HASTE was performed in 257. Ninety-three patients had both pre-ferumoxytol HASTE and FE-HASTE, and were included in this analysis. Qualitative image scores reflecting the degree and reliability of blood signal suppression were significantly higher for FE-HASTE images (2.9 [IQR 2.8-3.0] vs 1.8 [IQR 1.6-2.1], p < 0.001). Inter-reader agreement was moderate (k = 0.50, 95% CI 0.45-0.55). Blood signal suppression was more complete on FE-HASTE images than on pre-ferumoxytol HASTE, as indicated by lower mean homogeneity indices (24.5 [IQR 18.0-32.8] vs 108.0 [IQR 65.0-170.4], p < 0.001) and lower blood pool SNR for all regions (5.6 [IQR 3.2-10.0] vs 21.5 [IQR 12.5-39.4], p < 0.001). CONCLUSION: FE-HASTE black-blood imaging offers an effective, reliable, and simple approach for flow independent blood signal suppression. The technique holds promise as a fast and routine complement to bright-blood cardiovascular imaging with ferumoxytol.

Characterization and genome analysis of novel bacteriophages infecting the opportunistic human pathogens Klebsiella oxytoca and K. pneumoniae.

Klebsiella is a genus of well-known opportunistic human pathogens that are associated with diabetes mellitus and chronic pulmonary obstruction; however, this pathogen is often resistant to multiple drugs. To control this pathogen, two Klebsiella-infecting phages, K. oxytoca phage PKO111 and K. pneumoniae phage PKP126, were isolated from a sewage sample. Analysis of their host range revealed that they infect K. pneumoniae and K. oxytoca, suggesting host specificity for members of the genus Klebsiella. Stability tests confirmed that the phages are stable under various temperature (4 to 60 °C) and pH (3 to 11) conditions. A challenge assay showed that PKO111 and PKP126 inhibit growth of their host strains by 2 log and 4 log, respectively. Complete genome sequencing of the phages revealed that their genome sizes are quite different (168,758 bp for PKO111 and 50,934 bp for PKP126). Their genome annotation results showed that they have no human virulence-related genes, an important safety consideration. In addition, no lysogen-formation gene cluster was detected in either phage genome, suggesting that they are both virulent phages in their bacterial hosts. Based on these results, PKO111 and PKP126 may be good candidates for development of biocontrol agents against members of the genus Klebsiella for therapeutic purposes. A comparative analysis of tail-associated gene clusters of PKO111 and PKP126 revealed relatively low homology, suggesting that they might differ in the way they recognize and infect their specific hosts.

Anatomic variations of lower extremity venous system in varicose vein patients: demonstration by three-dimensional CT venography.

Background Understanding the anatomy of the lower extremity veins is essential for successful varicose vein treatment. Computed tomography (CT) venography may be used to obtain a comprehensive overview and detailed information regarding this. Purpose To describe anatomic variations of the lower extremity venous system in patients with varicose veins, using three-dimensional (3D) CT venography. Material and Methods A total of 810 limbs in 405 patients with suspected varicose veins were prospectively referred to undertake CT venography and included in our study population retrospectively. The CT venography images were evaluated by consensus of two cardiovascular radiologists. Anatomical variations of the lower extremity venous system and their incidence were analyzed. Specifically, the number of tributaries at saphenofemoral junction, relative location of the great saphenous vein (GSV) with respect to the common femoral artery bifurcation, pattern of saphenopopliteal junction, and end of thigh extension from the small saphenous vein (SSV) were assessed. Results The most frequent number of tributaries joining the GSV was four (44.4%, 360/810). Only 0.7% (6/810) of the limbs demonstrated unusual location of the GSV between the bifurcated superficial and deep femoral arteries. The most common pattern of veins at the saphenopopliteal junction was a larger caliber of saphenopopliteal junction than thigh extension from SSV (43.8%, 355/810), end of which joining the femoral vein directly (41.0%, 288/703). Conclusion CT venography with 3D reconstruction can be used to understand the anatomy of lower extremity veins and how their variations contribute to varicose veins.

Cardiac Magnetic Resonance Predictor of Ventricular Function after Surgical Coronary Revascularization.

We evaluated echocardiographic changes of left ventricular (LV) function in coronary artery bypass grafting (CABG) patients with LV dysfunction, and examined cardiac magnetic resonance (CMR) parameters associated with improved LV function. Seventy-seven CABG patients presenting with decreased LV ejection fraction (LVEF, ≤ 35%) and who underwent preoperative gadolinium-enhanced CMR were enrolled. A 16-segment model was used to analyze CMR imaging. A viable myocardial segment was defined as ≤ 50% transmural extent of late gadolinium enhancement. Serial echocardiographic examinations were performed preoperatively, pre-discharge (median 6 days), and during postoperative year 1 (median 11 months) in 70 patients. Predictors of absolute increase in LVEF (≥ 5%) and proportional changes in LVEF were analyzed. Serial echocardiography demonstrated that LVEF measured 28.6% ± 5.4% preoperatively, 31.5% ± 8.0% median 6 days, and 42.1% ± 10.5% median 11 months postoperatively. Absolute increase of LVEF was observed in 27 patients at pre-discharge and in 24 patients by median 11 months. Proportional changes in LVEF at postoperative median 6 days and 11 months were 14% ± 28% and 57% ± 45%, respectively. The median number of viable myocardial segments was 14 (range, 9-16) in the 16 segment CMR model. Multivariable models demonstrated that the median number of overall viable myocardial segments (≥ 14) in preoperative CMR was associated with absolute increase (P = 0.046) and proportional changes (P = 0.005) in LVEF. In conclusion, the number of viable myocardial segments (≥ 14) in preoperative CMR predicted LV function improvement after CABG in patients with LV dysfunction.

Prognostic Value of Cardiac MR Imaging for Preoperative Assessment of Patients with Severe Functional Tricuspid Regurgitation.

Purpose To explore the prognostic value of cardiac magnetic resonance (MR) imaging in predicting postoperative cardiac death in patients with severe functional tricuspid regurgitation (TR). Materials and Methods This study was approved by the institutional review board, and written informed consent was obtained from all patients. Prospectively collected data included cardiac MR images, New York Heart Association (NYHA) functional class, a comprehensive laboratory test, and clinical events over the follow-up period in 75 consecutive patients (61 women and 14 men; mean age ± standard deviation, 59 years ± 9) undergoing corrective surgery for severe functional TR. Cox proportional hazards models were used to assess the association between cardiac MR parameters and outcomes. Results During a median follow-up period of 57 months (range, 21-82 months), cardiac mortality and all-cause mortality were 17.3% and 26.7%, respectively, with a surgical mortality of 6.7%. Cardiac death risk was lower with a higher right ventricular (RV) ejection fraction (EF) on cardiac MR images (hazard ratio per 5% higher EF = 0.790, P = .048). By adjusting for confounding variables, RV EF remained a significant predictor for cardiac death (P < .05) and major postoperative cardiac events (P < .05). The area under the receiver operating characteristic curve (AUC) confirmed the incremental role of RV EF on cardiac MR images in the prediction of postoperative cardiac death (AUC, 0.681-0.771; P = .041) and major postoperative cardiac events (AUC, 0.660-0.745; P = .044) on top of NYHA class. RV end-systolic volume index was also independently associated with these outcomes but failed to increase the AUC significantly. Conclusion Preoperative assessment of cardiac MR imaging-based RV EF provides independent and incremental prognostic information in patients undergoing corrective surgery for severe functional TR. (©) RSNA, 2016 Online supplemental material is available for this article.

Quantitative Assessment of Foot Blood Flow by Using Dynamic Volume Perfusion CT Technique: A Feasibility Study.

PURPOSE: To demonstrate the feasibility of foot blood flow measurement by using dynamic volume perfusion computed tomographic (CT) technique with the upslope method in an animal experiment and a human study. MATERIALS AND METHODS: The human study was approved by the institutional review board, and written informed consent was obtained from all patients. The animal study was approved by the research animal care and use committee. A perfusion CT experiment was first performed by using rabbits. A color-coded perfusion map was reconstructed by using in-house perfusion analysis software based on the upslope method, and the measured blood flow on the map was compared with the reference standard microsphere method by using correlation analysis. A total of 17 perfusion CT sessions were then performed (a) once in five human patients and (b) twice (before and after endovascular revascularization) in six human patients. Perfusion maps of blood flow were reconstructed and analyzed. The Wilcoxon signed rank test was used to prove significant differences in blood flow before and after treatment. RESULTS: The animal experiment demonstrated a strong correlation (R(2) = 0.965) in blood flow between perfusion CT and the microsphere method. Perfusion maps were obtained successfully in 16 human clinical sessions (94%) with the use of 32 mL of contrast medium and an effective radiation dose of 0.31 mSv (k factor for the ankle, 0.0002). The plantar dermis showed the highest blood flow among all anatomic structures of the foot, including muscle, subcutaneous tissue, tendon, and bone. After a successful revascularization procedure, the blood flow of the plantar dermis increased by 153% (P = .031). The interpretations of the color-coded perfusion map correlated well with the clinical and angiographic findings. CONCLUSION: Perfusion CT could be used to measure foot blood flow in both animals and humans. It can be a useful modality for the diagnosis of peripheral arterial disease by providing quantitative information on foot perfusion status.

Feasibility of 320-row area detector CT coronary angiography using 40 mL of contrast material: assessment of image quality and diagnostic accuracy.

OBJECTIVES: To assess the image quality and diagnostic accuracy of 320-row area detector CT (320-ADCT) coronary angiography using 40 mL of contrast material in comparison with 60-mL protocol. METHODS: This retrospective study included 183 patients who underwent 320-ADCT coronary angiography using 40 mL of contrast and additional 183 sex- and body mass index-matched patients using 60 mL of contrast constituting the control group. Both groups used the same 5-mL/sec injection rate. Quantitative image quality measurements and diagnostic accuracies were calculated and compared. RESULTS: Mean attenuation and contrast-to-noise ratio (CNR) at the aorta and all coronary arteries were lower in the 40-mL group than in the 60-mL group (all, p < 0.05), except for the CNR at proximal coronary arteries at 100 kVp (p = 0.073). However, the proportion of coronary segments with vessel attenuation >250 HU was not different between groups (all, p > 0.05), except for distal coronary arteries at 80 kVp (p = 0.001). Furthermore, there were no differences in per-patient and per-segment diagnostic accuracies between the groups (all, p > 0.05). CONCLUSIONS: 320-ADCT coronary angiography using 40 mL of contrast showed image quality and diagnostic accuracy comparable to the 60-mL protocol, demonstrating the clinical feasibility of lowering the risk of contrast-induced nephropathy through contrast volume reduction. KEY POINTS: • 320-ADCT might enable reduction of contrast material volume. • A 40-mL contrast protocol for 320-ADCT provided acceptable image quality. • A 40-mL contrast protocol for 320-ADCT demonstrated sufficient diagnostic accuracy.

Magnetic Resonance Imaging of Reverse Remodeling After Coronary Revascularization in Ischemic Heart Disease　- Morphologic Evaluation.

BACKGROUND: Coronary revascularization has been shown to induce left ventricular (LV) reverse remodeling (RR). The serial morphologic changes in enhanced necrotic tissue during RR on cardiac magnetic resonance imaging (CMR) have not been investigated.Methods and Results:This retrospective study included 26 patients with severe LV systolic dysfunction (ejection fraction [EF], <35% on echocardiography) who underwent CMR before and >6 months after surgical revascularization. Of 26 patients, 20 had a reduction of ≥10% in end-diastolic and end-systolic volumes (classified as RR group). The RR group had improvement in EF after revascularization (28.8±6.6% vs. 40.6±7.8%, P<0.0001), and no change in absolute infarct mass (17.3±10.9 g vs. 17.5±10.4 g, P=0.8), but an increase in relative infarct mass (21.0±13.7% vs. 26.5±19.4%, P=0.01) due to reduction of myocardial mass after revascularization. Significant increase in regional transmural extent (30.3±21.6 vs. 42.6±22.8, P<0.0001) and in thickness of enhanced tissue (4.2±1.5 mm vs. 5.9±1.8 mm, P<0.0001) was found in the RR group. No significant differences were observed in any of the variables in the non-RR group. CONCLUSIONS: In patients with chronic myocardial ischemic dysfunction, significant volume reduction after revascularization led to significant increase in regional transmural extent of the enhanced area without a change in absolute infarct mass, on CMR. (Circ J 2016; 80: 2513-2519).

Changes in Right Ventricular Volume and Function After Tricuspid Valve Surgery　- Tricuspid Annuloplasty vs. Tricuspid Valve Replacement.

BACKGROUND: There is a concern that clinical outcome of tricuspid valve replacement (TVR) is inferior compared with tricuspid annuloplasty (TAP). The aim of this study was therefore to compare changes in right ventricular (RV) volume and function following TAP with that following TVR on cardiac magnetic resonance imaging (CMR) in patients with severe functional tricuspid regurgitation (TR). METHODS AND RESULTS: Forty patients who underwent surgery for severe functional TR and who underwent CMR preoperatively and on postoperative follow-up (24.8±13.3 months after surgery) were enrolled. Thirteen patients underwent TAP (TAP group) and 27 patients underwent TVR (TVR group). Both RV end-diastolic and end-systolic volume indices decreased significantly after surgery (from 178.9±53.9 to 116.3±26.7 ml/m(2), P<0.001, and from 95.7±36.1 to 67.3±28.0 ml/m(2), P<0.001, respectively), without intergroup differences. In the TAP group, RV ejection fraction (EF) was preserved following surgery (from 43.3±9.5 to 46.9±10.9%, P=0.312). In the TVR group, however, it decreased significantly following surgery (from 51.8±9.2 to 42.4±12.3%, P<0.001). In addition, postoperative RVEF was lower in the TVR than TAP group, with a marginal significance (mean difference, -6.967; 95% confidence interval: -14.529 to 0.595; P=0.070). CONCLUSIONS: For patients with severe functional TR, both TAP and TVR are beneficial for reduction of RV volume indices. TAP, however, might be superior to TVR, because RVEF is well preserved following surgery. (Circ J 2016; 80: 1142-1147).

Assessment of diffuse myocardial fibrosis by using MR imaging in asymptomatic patients with aortic stenosis.

PURPOSE: To assess whether native T1 mapping provides noninvasive estimation of diffuse myocardial fibrosis and whether it correlates with subclinical myocardial dysfunction in asymptomatic patients with aortic stenosis (AS). MATERIALS AND METHODS: The local institutional review board approved the study, and all patients gave informed consent. Eighty asymptomatic patients with moderate or severe AS and normal left ventricular (LV) ejection fraction (mean age, 67 years; range, 31-81 years) and 15 sex-matched control subjects (mean age, 33 years; range, 23-41 years) were prospectively enrolled. Patients underwent two-dimensional echocardiography, speckle tracking imaging, and cardiac 3.0-T magnetic resonance (MR) imaging, including mapping of T1 relaxation time by using the modified Look-Locker inversion-recovery sequence. Correlations between native T1 values and the degree of diffuse fibrosis in myocardial specimens obtained during aortic valve replacement surgery were analyzed in a subset of 20 patients. Correlations between parameters of myocardial function and structure and native T1 values were assessed with Pearson correlation coefficients. RESULTS: Native T1 values correlated well with the degree of diffuse myocardial fibrosis in intraoperative myocardial biopsy specimens (r = 0.777, P < .001) and differed significantly between patients with AS and control subjects (1208 msec ± 45 vs 1169 msec ± 21, P < .001). LV volumes and mass differed significantly according to AS groups, categorized by T1 tertiles (all P < .001), as well as degree of AS severity (0.55 cm(2)/m(2) ± 0.14 for lowest native T1 tertile, 0.46 cm(2)/m(2) ± 0.12 for middle native T1 tertile, and 0.45 cm(2)/m(2) ± 0.13 for highest native T1 tertile [P = .008] for indexed aortic valve area at echocardiography). Native T1 correlated significantly with global longitudinal strain measured with two-dimensional speckle tracking imaging (r = 0.598, P < .001), e' velocity (r = -0.437, P < .001), and indexed left atrial volume (r = 0.475, P < .001). CONCLUSION: Native T1 mapping provides a noninvasive estimation of diffuse myocardial fibrosis and correlates with subclinical myocardial dysfunction in asymptomatic patients with AS.