A coronary CT angiography-derived myocardial radiomics model for predicting adverse outcomes in chronic myocardial infarction.

BACKGROUND: The prognostic efficacy of a coronary computed tomography angiography (CCTA)-derived myocardial radiomics model in patients with chronic myocardial infarction (MI) is unclear. METHODS: In this retrospective study, a cohort of 236 patients with chronic MI who underwent both CCTA and cardiac magnetic resonance (CMR) examinations within 30 days were enrolled and randomly divided into training and testing datasets at a ratio of 7:3. The clinical endpoints were major adverse cardiovascular events (MACE), defined as all-cause death, myocardial reinfarction and heart failure hospitalization. The entire three-dimensional left ventricular myocardium on CCTA images was segmented as the volume of interest for the extraction of radiomics features. Five models, namely the clinical model, CMR model, clinical+CMR model, CCTA-radiomics model, and clinical+CCTA-radiomics model, were constructed using multivariate Cox regression. The prognostic performances of these models were evaluated through receiver operating characteristic curve analysis and the index of concordance (C-index). RESULTS: Fifty-one (20.16%) patients experienced MACE during a median follow-up of 1439.5 days. The predictive performance of the CCTA-radiomics model surpassed that of the clinical model, CMR model, and clinical+CMR model in both the training (area under the curve (AUC) of 0.904 vs. 0.691, 0.764, 0.785; C-index of 0.88 vs. 0.71, 0.75, 0.76, all p values <0.001) and testing (AUC of 0.893 vs. 0.704, 0.851, 0.888; C-index of 0.86 vs. 0.73, 0.85, 0.85, all p values <0.05) datasets. CONCLUSIONS: The CCTA-based myocardial radiomics model is a valuable tool for predicting adverse outcomes in chronic MI, providing incremental value to conventional clinical and CMR parameters.

Incremental Prognostic Value of Left Atrial Strain in Patients With Suspected Myocarditis and Preserved Left Ventricular Ejection Fraction.

BACKGROUND: Analysis of left atrial (LA) strain and left atrioventricular coupling index (LACI) have prognostic value in cardiovascular diseases. However, the prognostic value of LA strain and LACI in patients with suspected myocarditis and preserved left ventricular ejection fraction (LVEF) is unclear. PURPOSE: To investigate the prognostic value of LA strain and LACI in patients with suspected myocarditis and preserved LVEF in comparison with conventional MRI outcome predictors. STUDY TYPE: Retrospective. POPULATION: One hundred sixty-five patients with clinically suspected myocarditis and preserved LVEF with available follow-up data. FIELD STRENGTH/SEQUENCE: Steady-state free precession cine and phase-sensitive inversion recovery segmented gradient echo late gadolinium enhancement sequences at 3.0 T. ASSESSMENT: Left ventricular (LV) and LA strain were evaluated using feature tracking. LACI was calculated as the ratio of LA and LV volumes at LV end-diastole. Patients were followed-up with the primary endpoint being major adverse cardiovascular events (MACE). STATISTICAL TESTS: Independent-samples t-test and Mann-Whitney U test to compare patients with and without MACE, receiver operating characteristic (ROC) curve analysis to define high/low risk groups, Kaplan-Meier survival analysis and Cox proportional hazards regression to assess prognosis. A P value of <0.05 was considered statistically significant. RESULTS: The associations of LV strain parameters (including global radial, circumferential, and longitudinal strain) and LACI with MACE were not significant (P = 0.511, 0.108, 0.148, and 0.847, respectively). An optimal LA conduit strain (Ԑe) cutoff value of 10.4% was identified to best classify patients into low- and high-risk groups. Only Ԑe was significantly associated with MACE in both univariable (hazards ratio [HR] 0.936, 95% confidence interval [CI] 0.884-0.991) and multivariable Cox survival analyses (HR 0.937, 95% CI 0.884-0.994). DATA CONCLUSION: LA conduit strain has prognostic value in patients with suspected myocarditis and preserved LVEF, incremental to conventional MRI outcome predictors, whereas LACI was not associated with MACE occurrence. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

Analysis of coronary computed tomography angiography-derived pericoronary fat attenuation index characteristics in the diagnostic assessment of patients with Takayasu arteritis.

Background: The clinical value of pericoronary adipose tissue in assessing Takayasu arteritis (TAK) with coronary artery involvement (CAI) is yet to be determined. The purpose of this study was to investigate the characteristics of pericoronary fat attenuation index (FAI) derived from coronary computed tomography angiography (CTA) in patients with TAK. Methods: This is a retrospective study involving enrollment of 111 consecutive patients (mean age, 33.92±12.48 years) who were diagnosed as TAK, of which 52 patients had coronary artery involvement (TAK-CAI) and 59 patients without coronary artery involvement (TAK-nonCAI). Based on the extent of coronary artery lesion, the TAK-CAI group was further classified into localized group (n=25) and diffused group (n=27). Furthermore, patients with TAK were divided into active group (n=33) and inactive group (n=78). Meanwhile, 51 gender-matched individuals with normal appearance in coronary CTA examination were enrolled as the control group. The pericoronary FAI was quantitatively evaluated on each coronary CTA examination groups. The diagnostic value of pericoronary FAI was determined using the area under the curve (AUC) of the receiver operating characteristic. Results: A higher pericoronary FAI was found in TAK-nonCAI group than control group with normal coronary arteries (P<0.001). Multivariate analysis showed that the FAI is an independent risk factor for coronary involvement in TAK patients [odds ratio (OR): 1.23, 95% confidence interval (CI): 1.13-1.35, P<0.001]. With the best cut-off value of -86.50, the pericoronary FAI identified coronary involvement with 67.8% sensitivity and 74.5% specificity (AUC: 0.794, 95% CI: 0.713-0.875, P<0.001). Multivariate analysis showed that the pericoronary FAI is an independent risk factor for determination of active TAK patients (OR: 1.57, 95% CI: 1.25-1.97, P<0.001). With the best cut-off value of -79.50, the pericoronary FAI identified active inflammation with 93.9% sensitivity and 74.4% specificity (AUC: 0.911, 95% CI: 0.860-0.962, P<0.001). Conclusions: Coronary CTA-derived FAI is significantly increased in patients with TAK and can be used as a reliable biomarker to distinguish TAK patients from those with normal coronary arteries, and determine the extent of TAK inflammation.

Prognostic Significance of Cardiac Magnetic Resonance in Left Atrial and Biventricular Strain Analysis during the Follow-Up of Suspected Myocarditis.

To assess the variation in left atrial (LA) and biventricular strain and its prognostic value in the course of suspected myocarditis, this retrospective study included 55 patients with clinically suspected myocarditis who underwent cardiac magnetic resonance (CMR) examinations at baseline and follow-up periods. Cine images were used for feature tracking analysis. Paired Student's t test, McNemar's test, and Cox proportional hazard regression were used for statistical analysis. The LA total emptying fraction was the only functional index that showed a statistically significant improvement. The initial LA peak's late negative strain rate (SRa) was the only parameter with a significant predictive power of major adverse cardiac events under univariable (hazard ratio [HR] 2.396, 95% confidence interval [CI] 1.044-5.498, p = 0.039) and multivariable Cox survival analysis when adjusted by LA strain parameters (HR 5.072, 95% CI 1.478-17.404, p = 0.010), LA strain and functional parameters (HR 7.197, 95% CI 1.679-30.846, p = 0.008), and LA and biventricular strain and functional parameters (HR 10.389, 95% CI 2.250-47.977, p = 0.003). Thus, our findings indicate that CMR strain is useful for monitoring LA and ventricular function in suspected myocarditis, that LA function may recover preceding ventricular function changes, and that LA strain may serve as an incremental tool to predict adverse outcomes.

Influence of MRI-based boundary conditions on type B aortic dissection simulations in false lumen with or without abdominal aorta involvement.

Most computational hemodynamic studies of aortic dissections rely on idealized or general boundary conditions. However, numerical simulations that ignore the characteristics of the abdominal branch arteries may not be conducive to accurately observing the hemodynamic changes below the branch arteries. In the present study, two men (M-I and M-II) with type B aortic dissection (TBAD) underwent arterial-phase computed tomography angiography and four-dimensional flow magnetic resonance imaging (MRI) before and after thoracic endovascular aortic repair (TEVAR). The finite element method was used to simulate the computational fluid dynamic parameters of TBAD [false lumen (FL) with or without visceral artery involvement] under MRI-specific and three idealized boundary conditions in one cardiac cycle. Compared to the results of zero pressure and outflow boundary conditions, the simulations with MRI boundary conditions were closer to the initial MRI data. The pressure difference between true lumen and FL after TEVAR under the other three boundary conditions was lower than that of the MRI-specific results. The results of the outflow boundary conditions could not characterize the effect of the increased wall pressure near the left renal artery caused by the impact of Tear-1, which raised concerns about the distal organ and limb perfused by FL. After TEVAR, the flow velocity and wall pressure in the FL and the distribution areas of high time average wall shear stress and oscillating shear index were reduced. The difference between the calculation results for different boundary conditions was lower in M-II, wherein FL did not involve the abdominal aorta branches than in M-I. The boundary conditions of the abdominal branch arteries from MRI data might be valuable in elucidating the hemodynamic changes of the descending aorta in TBAD patients before and after treatment, especially those with FL involving the branch arteries.

Predictive Value of Coronary Artery Calcium in Patients Receiving Computed Tomography Pulmonary Angiography for Suspected Pulmonary Embolism in the Emergency Department.

PURPOSE: Coronary artery calcium (CAC) is a frequent incidental finding on computed tomography pulmonary angiogram (CTPA) in the evaluation of pulmonary embolism (PE) in the emergency department (ED); however, its prognostic value is unclear. In this study, we interrogate the prognostic value of CAC identified on CTPA in predicting adverse outcomes in the evaluation of PE in the ED. MATERIALS AND METHODS: In this retrospective cohort study, we identified 610 patients presenting to the ED in 2013 and evaluated with CTPA for suspected PE. Ordinal CAC scores were evaluated as absent (0), mild (1), moderate (2), or severe (3) in each of the 4 main coronary arteries. Composite CAC scores were subsequently compared against adverse clinical outcomes, defined as intensive care unit admission, hospital stay longer than 72 hours, or death during hospital course or at 6-month follow-up, using univariate and multivariate logistic regression analyses. Relevant exclusion criteria included a history of cardiovascular disease. RESULTS: In all, 365 patients met the inclusion criteria (231 women, mean age 56±16 y) with 132 patients (36%) having some degree of CAC and 16 (4%) having severe CAC. Known malignancy was present in 151 (41%) patients and composite adverse clinical outcomes were observed in 98 patients (32%). Age, presence of acute PE, malignancy, and presence of CAC were significant predictors of adverse outcomes on both univariate and multivariate analyses. CAC was not an independent predictor of short-term adverse outcomes on multivariate analysis ( P =0.06) when all patients were considered. However, when patients with known malignancy were excluded, CAC was an independent predictor of short-term adverse outcomes (odds ratio=2.5, confidence interval=1.1-5.5, P =0.03) independent of age and presence of PE. CONCLUSION: The presence of CAC on CT PA was predictive of adverse outcomes in patients without known cardiac disease presenting to the ED with suspected PE.

Diagnostic and Prognostic Value of Cardiac Magnetic Resonance Strain in Suspected Myocarditis With Preserved LV-EF: A Comparison Between Patients With Negative and Positive Late Gadolinium Enhancement Findings.

BACKGROUND: Late gadolinium enhancement (LGE) is absent in many patients with suspected myocarditis and preserved left ventricular ejection fraction (LV-EF), which poses difficulties in diagnosis and risk stratification. PURPOSE: To investigate the diagnostic and prognostic value of ventricular myocardial strain in patients with suspected myocarditis, preserved LV-EF, and negative Lake Louis Criteria (LLC) by comparing the findings in LGE negative and LGE positive patients. STUDY TYPE: Retrospective. POPULATION: A total of 108 patients with clinically suspected myocarditis who did not satisfy LLC were divided into LGE negative (N = 65) and LGE positive (N = 43) groups. A control group consisted of 50 healthy volunteers. FIELD STRENGTH/SEQUENCE: Steady-state free precession cine and phase-sensitive inversion recovery segmented gradient echo LGE sequences at 3.0 T. ASSESSMENT: Myocardial strain of the ventricles was evaluated by feature tracking, major adverse cardiovascular events (MACE) were assessed during follow-up since the date of magnetic resonance examination. STATISTICAL TESTS: Independent-samples t test, Mann-Whitney U test, receiver operating characteristic curve analysis, and Cox proportional hazard regression were performed. A P-value <0.05 was considered statistically significant. RESULTS: Cardiac function and myocardial deformability were impaired in all patients relative to controls. Left ventricular-global radial (LV-GRS), circumferential (LV-GCS), and longitudinal (LV-GLS) strain had diagnostic value, even in LGE negative patients (sensitivity = 0.446, 0.523, and 0.662; specificity = 0.92, 0.80, and 0.64; AUC = 0.685, 0.675, and 0.648, respectively). After a median follow-up of 530.5 (interquartile range: 168.5-969.25) days, MACE occurred in 18 (16.67%) patients. Right ventricular GLS showed prognostic value in all patients and in LGE negative patients, both in univariable analysis (hazard ratio [HR] 1.049, 95% confidence interval [CI] 1.001-1.099 and HR 1.068, 95% CI 1.011-1.127, respectively) and in multivariable Cox survival analysis. LV-GLS was associated with MACE in LGE positive patients in multivariable Cox survival analysis. DATA CONCLUSION: Myocardial strain provides diagnostic and prognostic value in suspected myocarditis with preserved LV-EF, even in the absence of LGE. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: 2.

CT Findings of Pulmonary Metastases from Primary Cardiac Angiosarcoma.

BACKGROUND: Primary cardiac angiosarcoma is a rare malignancy with high predilection to involve surrounding structures such as pulmonary metastases. We analysed the chest computed tomography (CT) imaging features of patients diagnosed with primary cardiac angiosarcoma with pulmonary metastases in this study. METHODS: This study retrospectively reviewed 12 patients with confirmed primary cardiac angiosarcoma, out of which eight (all men) with pulmonary metastasis were included in the analysis. The patients' age ranged from 17 to 74 (mean: 48) years. CT was performed in all patients with unenhanced, contrast-enhanced, and both scans were done in 1, 3 and 4 patients, respectively. RESULTS: Nodular lesions were observed in 7 patients with multiple solid nodules observed in 6 out of 7 patients. A solitary solid nodule was found in the remaining patient in the upper lobe and apical segment of the right lung with a diameter of 11.7 mm. All solid nodules were distributed along with bronchovascular bundles in the lungs, and their maximum diameter ranged from 2.3 to 19.9 mm. Nodules larger than 10 mm in diameter were heterogeneously enhanced on contrast-enhanced CT images (5/8 patients), whereas those smaller than 10 mm were homogeneously enhanced (3/8 patients). Other imaging features, namely the tree-in-bud pattern, emphysema, pleural effusion, and mediastinal lymph node enlargement, were observed in 4, 3, 3, and 2 patients, respectively. CONCLUSION: CT enhancement features of pulmonary metastasis in patients with primary cardiac angiosarcoma depend on the size of pulmonary nodules, with larger ones being heterogeneous and smaller ones homogeneous. Other signs are less noticed.

Deep learning based fully automatic segmentation of the left ventricular endocardium and epicardium from cardiac cine MRI.

BACKGROUND: The segmentation of cardiac medical images is a crucial step for calculating clinical indices such as wall thickness, ventricular volume, and ejection fraction. METHODS: In this study, we introduce a method named LsUnet that combines multi-channel, fully convolutional neural network, and annular shape level-set methods for efficiently segmenting cardiac cine magnetic resonance (MR) images. In this method, the multi-channel deep learning algorithm is applied to train the segmentation task to extract the left ventricle (LV) endocardial and epicardial contours. Next, the segmentation contours from the multi-channel deep learning method are incorporated into a level-set formulation, which is dedicated explicitly to detecting annular shapes to assure the segmentation's accuracy and robustness. RESULTS: The proposed automatic approach was evaluated on 95 volumes (total 1,076 slices, ~80% as for training datasets, ~20% 2D as for testing datasets). This combined multi-channel deep learning and annular shape level-set segmentation method achieved high accuracy with average Dice values reaching 92.15% and 95.42% for LV endocardium and epicardium delineation, respectively, in comparison to the reference standard (the manual segmentation). CONCLUSIONS: A novel method for fully automatic segmentation of the LV endocardium and epicardium from different MRI datasets is presented. The proposed workflow is accurate and robust compared to the reference and other state-of-the-art methods.

Clinical and Imaging Features of Primary Cardiac Angiosarcoma.

This study aims to explore computed tomography (CT) and magnetic resonance imaging (MRI) features of patients diagnosed with primary cardiac angiosarcoma. The study involved the analysis of 12 patients diagnosed with primary cardiac angiosarcoma who underwent non-contrast (8/12) or contrast-enhanced CT (10/12) or MRI (4/12). Imaging appearances, including the tumor location and adjacent infiltration, were analyzed. All 12 lesions were located in the right atrium with a broad base. Adjacent invasion including the tricuspid valve and right ventricle (2/12), inferior or superior vena cava (2/12), pericardium (10/12), and right coronary artery (7/12) was common. On unenhanced CT scans, tumors in two patients were homogeneous in density, whereas the others were inhomogeneous. Ten patients showed heterogeneous enhancement. The enhancement pattern showed no direct correlation with the differentiation degree of the tumor. Four lesions manifested as heterogeneous intensity, with hyperintense hemorrhage foci on both T1- and T2-weighted MRI. Three showed rim enhancement and one showed patchy enhancement. Primary cardiac angiosarcoma often involves the right side of the heart with infiltration of peripheral structures. CT features include typical inhomogeneous density on unenhanced scans and heterogeneous centripetal enhancement on enhanced scans. A cauliflower-like appearance on both T1- and T2-weighted MRI is common. The characteristic enhancement pattern of MRI remains to be determined.

Left ventricular pseudoaneurysm complicating a ruptured isolated congenital diverticulum.

We report a case of 41-year-old woman who presented with chest tightness and shortness of breath. Transthoracic echocardiogram (TTE) showed left ventricular (LV) pseudoaneurysm of the inferior wall with preserved LV systolic function. Coronary angiogram was normal. Surgical repair of the pseudoaneurysm with a pericardial patch was performed, and pathological results confirmed rupture of an isolated congenital LV diverticulum, as the most likely etiology.

Cardiac magnetic resonance imaging of primary cardiac tumors.

Cardiac magnetic resonance (CMR) offers superior advantages in cardiac imaging due to supplying a greater field of view, excellent soft-tissue imaging, and multiplanar imaging capabilities. CMR imaging can evaluate the characteristics of cardiac tumors by visualizing the relationship between the tumor and surrounding tissues, and plays a vital role in assisting the formulation of the surgical plan, the assessment of tumor progression, and the monitoring of postoperative tumor recurrence and metastasis. In this review, we present the clinical manifestations and imaging features of different cardiac tumors. The superior performance of CMR in preoperative diagnosis, surgical treatment, and postoperative follow-up of patients with heart tumors are also highlighted.

Surveillance of abdominal aortic aneurysm using accelerated 3D non-contrast black-blood cardiovascular magnetic resonance with compressed sensing (CS-DANTE-SPACE).

BACKGROUND: 3D non-contrast high-resolution black-blood cardiovascular magnetic resonance (CMR) (DANTE-SPACE) has been used for surveillance of abdominal aortic aneurysm (AAA) and validated against computed tomography (CT) angiography. However, it requires a long scan time of more than 7 min. We sought to develop an accelerated sequence applying compressed sensing (CS-DANTE-SPACE) and validate it in AAA patients undergoing surveillance. METHODS: Thirty-eight AAA patients (all males, 73 ± 6 years) under clinical surveillance were recruited for this study. All patients were scanned with DANTE-SPACE (scan time 7:10 min) and CS-DANTE-SPACE (scan time 4:12 min, a reduction of 41.4%). Nine 9 patients were scanned more than 2 times. In total, 50 pairs of images were available for comparison. Two radiologists independently evaluated the image quality on a 1-4 scale, and measured the maximal diameter of AAA, the intra-luminal thrombus (ILT) and lumen area, ILT-to-muscle signal intensity ratio, and the ILT-to-lumen contrast ratio. The sharpness of the aneurysm inner/outer boundaries was quantified. RESULTS: CS-DANTE-SPACE achieved comparable image quality compared with DANTE-SPACE (3.15 ± 0.67 vs. 3.03 ± 0.64, p = 0.06). There was excellent agreement between results from the two sequences for diameter/area and ILT ratio measurements (ICCs> 0.85), and for quantifying growth rate (3.3 ± 3.1 vs. 3.3 ± 3.4 mm/year, ICC = 0.95.) CS-DANTE-SPACE showed a higher ILT-to-lumen contrast ratio (p = 0.01) and higher sharpness than DANTE-SPACE (p = 0.002). Both sequences had excellent inter-reader reproducibility for quantitative measurements (ICC > 0.88). CONCLUSION: CS-DANTE-SPACE can reduce scan time while maintaining image quality for AAA imaging. It is a promising tool for the surveillance of patients with AAA disease in the clinical setting.

Extending Cardiac Functional Assessment with Respiratory-Resolved 3D Cine MRI.

This study aimed to develop a cardiorespiratory-resolved 3D magnetic resonance imaging (5D MRI: x-y-z-cardiac-respiratory) approach based on 3D motion tracking for investigating the influence of respiration on cardiac ventricular function. A highly-accelerated 2.5-minute sparse MR protocol was developed for a continuous acquisition of cardiac images through multiple cardiac and respiratory cycles. The heart displacement along respiration was extracted using a 3D image deformation algorithm, and this information was used to cluster the acquired data into multiple respiratory phases. The proposed approach was tested in 15 healthy volunteers (7 females). Cardiac function parameters, including the end-systolic volume (ESV), end-diastolic volume (EDV), stroke volume (SV), and ejection fraction (EF), were measured for the left and right ventricle in both end-expiration and end-inspiration. Although with the proposed 5D cardiac MRI, there were no significant differences (p > 0.05, t-test) between end-expiration and end-inspiration measurements of the cardiac function in volunteers, incremental respiratory motion parameters that were derived from 3D motion tracking, such as the depth, expiration and inspiration distribution, correlated (p < 0.05, correlation coefficient, Mann-Whitney) with those volume-based parameters of cardiac function and varied between genders. The obtained initial results suggested that this new approach allows evaluation of cardiac function during specific respiratory phases. Thus, it can enable investigation of effects related to respiratory variability and better assessment of cardiac function for studying respiratory and/or cardiac dysfunction.

Evaluation of the distribution and progression of intraluminal thrombus in abdominal aortic aneurysms using high-resolution MRI.

BACKGROUND: Intraluminal thrombus (ILT) signal intensity on MRI has been studied as a potential marker of abdominal aortic aneurysm (AAA) progression. PURPOSE: 1) To characterize the relationship between ILT signal intensity and AAA diameter; 2) to evaluate ILT change over time; and 3) to assess the relationship between ILT features and AAA growth. STUDY TYPE: Prospective. SUBJECTS: Eighty AAA patients were imaged, and a subset (n = 41) were followed with repeated MRI for 16 ± 9 months. FIELD STRENGTH/SEQUENCE: 3D black-blood fast-spin-echo sequence at 3 T. ASSESSMENT: ILT was designated as "bright" if the signal was greater than 1.2 times that of adjacent psoas muscle. AAAs were divided into three groups based on ILT: Type 1: bright ILT; Type 2: isointense ILT; Type 3: no ILT. During follow-up, an active ILT change was defined as new ILT formation or an increase in ILT signal intensity to bright; stable ILT was defined as no change in ILT type or ILT became isointense from bright previously. STATISTICAL TESTS: Shapiro-Wilk test; Mann-Whitney U-test; Fisher's exact test; Kruskal-Wallis test; Spearman's r; intraclass correlation coefficient (ICC), Cohen's kappa. RESULTS: AAAs with Type 1 ILT were larger than those with Types 2 and 3 ILT (5.1 ± 1.1 cm, 4.4 ± 0.9 cm, 4.2 ± 0.8 cm, P = 0.008). The growth rate of AAAs with Type 1 ILT was significantly greater than that of AAAs with Types 2 and 3 ILT (2.6 ± 2.5, 0.6 ± 1.3, 1.5 ± 0.6 mm/year, P = 0.01). During follow-up, AAAs with active ILT changes had a 3-fold increased growth rate compared with AAAs with stable ILT (3.6 ± 3.0 mm/year vs. 1.2 ± 1.5 mm/year, P = 0.008). DATA CONCLUSION: AAAs with bright ILT are larger in diameter and grow faster. Active ILT change is associated with faster AAA growth. Black-blood MRI can characterize ILT features and monitor their change over time, which may provide new insights into AAA risk assessment. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2019;50:994-1001.

Prostaglandins in the pathogenesis of kidney diseases.

Prostaglandins (PGs) are important lipid mediators produced from arachidonic acid via the sequential catalyzation of cyclooxygenases (COXs) and specific prostaglandin synthases. There are five subtypes of PGs, namely PGE2, PGI2, PGD2, PGF2α, and thromboxane A2 (TXA2). PGs exert distinct roles by combining to a diverse family of membrane-spanning G protein-coupled prostanoid receptors. The distribution of these PGs, their specific synthases and receptors vary a lot in the kidney. This review summarized the recent findings of PGs together with the COXs and their specific synthases and receptors in regulating renal function and highlighted the insights into their roles in the pathogenesis of various kidney diseases.

MnTBAP therapy attenuates the downregulation of sodium transporters in obstructive kidney disease.

Ureteral obstruction is associated with reduced expressions of renal sodium transporters, which contributes to impaired urinary concentrating capacity. In this study, we employed a synthetic mitochondrial superoxide dismutase 2 (SOD2) mimic MnTBAP to investigate the role of mitochondrial oxidative stress in modulating the sodium transporters in obstructive kidney disease. Following unilateral ureteral obstruction (UUO) for 7 days, a global reduction of sodium transporters including NHE3, NCC, NKCC2, and ENaCα was observed as determined by qRT-PCR, Western Blotting or immunohistochemistry. Among these sodium transporters, the downregulation of NHE3, NCC, and NKCC2 was partially reversed by MnTBAP treatment. In contrast, the reduction of ENaCα was not affected by MnTBAP. The ß and γ subunits of ENaC were not significantly altered by ureteral obstruction or MnTBAP therapy. To further confirm the anti-oxidant effect of MnTBAP, we examined the levels of TBARs in the urine collected from the obstructed ureters of UUO mice and bladder of sham mice. As expected, the increment of urinary TBARs in UUO mice was entirely abolished by MnTBAP therapy, indicating an amelioration of oxidative stress. Meantime, we found that three types of SOD were all reduced in obstructed kidneys determined by qRT-PCR, which was unaffected by MnTBAP. Collectively, these results demonstrated an important role of mitochondrial oxidative stress in mediating the downregulation of sodium transporters in obstructive kidney disease.