Left Ventricular Wall Reconstruction with Autologous Vascularized Tunica Muscularis of Stomach in a Porcine Pilot Model.

INTRODUCTION: Surgical replacement of dysfunctional cardiac muscle with regenerative tissue is an important option to combat heart failure. But, current available myocardial prostheses like a Dacron or a pericardium patch neither have a regenerative capacity nor do they actively contribute to the heart's pump function. This study aimed to show the feasibility of utilizing a vascularized stomach patch for transmural left ventricular wall reconstruction. METHODS: A left ventricular transmural myocardial defect was reconstructed by performing transdiaphragmatic autologous transplantation of a vascularized stomach segment in six Lewe minipigs. Three further animals received a conventional Dacron patch as a control treatment. The first 3 animals were followed up for 3 months until planned euthanasia, whereas the observation period for the remaining 3 animals was scheduled 6 months following surgery. Functional assessment of the grafts was carried out via cardiac magnetic resonance tomography and angiography. Physiological remodeling was evaluated histologically and immunohistochemically after heart explantation. RESULTS: Five out of six test animals and all control animals survived the complex surgery and completed the follow-up without clinical complications. One animal died intraoperatively due to excessive bleeding. No animal experienced rupture of the stomach graft. Functional integration of the heterotopically transplanted stomach into the surrounding myocardium was observed. Angiography showed development of connections between the gastric graft vasculature and the coronary system of the host cardiac tissue. CONCLUSIONS: The clinical results and the observed physiological integration of gastric grafts into the cardiac structure demonstrate the feasibility of vascularized stomach tissue as myocardial prosthesis. The physiological remodeling indicates a regenerative potential of the graft. Above all, the connection of the gastric vessels with the coronary system constitutes a rationale for the use of vascularized and, therefore, viable stomach tissue for versatile tissue engineering applications.

Assessment of acute kidney injury with T1 mapping MRI following solid organ transplantation.

OBJECTIVES: To evaluate T1 mapping as a non-invasive, functional MRI biomarker in patients shortly after solid organ transplantation to detect acute postsurgical kidney damage and to correlate T1 times with renal function. METHODS: 101 patients within 2 weeks after solid organ transplantation (49 kidney transplantation, 52 lung transplantation) and 14 healthy volunteers were examined by MRI between July 2012 and April 2015 using the modified Look-Locker inversion recovery (MOLLI) sequence. T1 times in renal cortex and medulla and the corticomedullary difference were compared between groups using one-way ANOVA adjusted for multiple comparison with the Tukey test, and T1 times were correlated with renal function using Pearson's correlation. RESULTS: Compared to healthy volunteers T1 times were significantly increased after solid organ transplantation in the renal cortex (healthy volunteers 987 ± 102 ms; kidney transplantation 1299 ± 101 ms, p < 0.001; lung transplantation 1058 ± 96 ms, p < 0.05) and to a lesser extent in the renal medulla. Accordingly, the corticomedullary difference was diminished shortly after solid organ transplantation. T1 changes were more pronounced following kidney compared to lung transplantation, were associated with the stage of renal impairment and significantly correlated with renal function. CONCLUSIONS: T1 mapping may be helpful for early non-invasive assessment of acute kidney injury and renal pathology following major surgery such as solid organ transplantation. KEY POINTS: • Renal cortical T1 relaxation times are prolonged after solid organ transplantation. • Cortical T1 values increase with higher stages of renal function impairment. • Corticomedullary difference decreases with higher stages of renal function impairment. • Renal cortical T1 relaxation time and corticomedullary difference correlate with renal function. • T1 mapping may be helpful for non-invasive assessment of post-operative renal pathology.

Gd-EOB-DTPA-enhanced MRI for quantitative assessment of liver organ damage after partial hepatic ischaemia reperfusion injury: correlation with histology and serum biomarkers of liver cell injury.

OBJECTIVE: To evaluate Gd-EOB-DTPA-enhanced MRI for quantitative assessment of liver organ damage after hepatic ischaemia reperfusion injury (IRI) in mice. METHODS: Partial hepatic IRI was induced in C57Bl/6 mice (n = 31) for 35, 45, 60 and 90 min. Gd-EOB-DTPA-enhanced MRI was performed 1 day after surgery using a 3D-FLASH sequence. A subgroup of n = 9 animals with 60 min IRI underwent follow-up with MRI and histology 7 days after IRI. The total liver volume was determined by manual segmentation of the entire liver. The volume of functional, contrast-enhanced liver parenchyma was quantified by a region growing algorithm (visual threshold) and an automated segmentation (Otsu's method). The percentages of functional, contrast-enhanced and damaged non-enhanced parenchyma were calculated according to these volumes. MRI data was correlated with serum liver enzyme concentrations and histologically quantified organ damage using periodic acid-Schiff (PAS) staining. RESULTS: The percentage of functional (contrasted) liver parenchyma decreased significantly with increasing ischaemia times (control, 94.4 ± 3.3%; 35 min IRI, 89.3 ± 4.1%; 45 min IRI, 87.9 ± 3.3%; 60 min IRI, 68 ± 10.5%, p < 0.001 vs. control; 90 min IRI, 55.9 ± 11.5%, p < 0.001 vs. control). The percentage of non-contrasted liver parenchyma correlated with histologically quantified liver organ damage (r = 0.637, p < 0.01) and serum liver enzyme elevations (AST r = 0.577, p < 0.01; ALT r = 0.536, p < 0.05). Follow-up MRI visualized recovery of functional liver parenchyma (71.5 ± 8.7% vs. 84 ± 2.1%, p < 0.05), consistent with less histological organ damage on day 7. CONCLUSION: We demonstrated the feasibility of Gd-EOB-DTPA-enhanced MRI for non-invasive quantification of damaged liver parenchyma following IRI in mice. This novel methodology may refine the characterization of liver disease and could have application in future studies targeting liver organ damage. KEY POINTS: • Prolonged ischaemia times in partial liver IRI increase liver organ damage. • Gd-EOB-DTPA-enhanced MRI at hepatobiliary phase identifies damaged liver volume after hepatic IRI. • Damaged liver parenchyma quantified with MRI correlates with histological liver damage. • Hepatobiliary phase Gd-EOB-DTPA-enhanced MRI enables non-invasive assessment of recovery from liver injury.

Longitudinal evaluation of perfusion changes in acute and chronic renal allograft rejection using arterial spin labeling in translational mouse models.

PURPOSE: To examine the longitudinal changes of renal perfusion due to acute and chronic renal allograft rejection by using arterial spin labeling (ASL) MRI in translational mouse models of isogenic and allogenic kidney transplantation (ktx). MATERIALS AND METHODS: Acute rejection was induced by allogenic ktx of C57BL/6 (B6)-kidney grafts to BALB/c-recipients with prolonged cold ischemia (CIT) of 60 minutes (n = 13). To induce chronic rejection BALB/c-kidneys were transplanted into B6-recipients with short CIT of 30 minutes (n = 22). Isogenic grafts without rejection (n = 14 with prolonged, n = 9 with short CIT) and normal kidneys (n = 22) were used for comparison. Perfusion was measured on a 7T small-animal magnetic resonance imaging (MRI) scanner using flow-sensitive alternating inversion recovery (FAIR) ASL-sequences at day 1 and 6 (acute) or at week 3 and 6 (chronic) after surgery. Histological analyses of grafts included inflammation, vascular changes, and fibrosis. RESULTS: In the acute ktx model, ASL showed perfusion impairment in isogenic and allogenic kidney grafts. Perfusion of allografts further decreased until day 6 and remained stable in isografts without rejection (allogenic ktx 62 ± 21 vs. isogenic ktx 181 ± 39 ml/min/100g, P < 0.01). In the chronic ktx model, perfusion in isografts was similar to normal kidneys over the entire observation period. Perfusion was severely reduced in allografts compared to isografts (week 3: 28 ± 7 vs. 310 ± 46 ml/min/100g, P < 0.001, week 6: 32 ± 5 vs. 367 ± 72 ml/min/100g, P < 0.001). Histological analysis revealed severe inflammation, vascular occlusion, and rejection in allografts. Chronic rejection grafts showed endothelialitis, peritubular capillaritis, interstitial fibrosis, and tubular atrophy. CONCLUSION: ASL allows longitudinal assessment of renal perfusion impairment due to acute and chronic renal allograft rejection in translational mouse models. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1664-1672.

Diffusion-Weighted imaging and diffusion tensor imaging detect delayed graft function and correlate with allograft fibrosis in patients early after kidney transplantation.

PURPOSE: To combine diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) for detection of allograft dysfunction in patients early after kidney transplantation and to correlate diffusion parameters with renal function and renal histology of allograft biopsies. MATERIALS AND METHODS: Between day 4 and 11 after kidney transplantation 33 patients with initial graft function and 31 patients with delayed graft function (DGF) were examined with a 1.5T magnetic resonance imaging (MRI) scanner. DTI and DWI sequences were acquired and fractional anisotropy (FA), apparent diffusion coefficient (ADCmono), pure diffusion (ADCdiff ), and the perfusion fraction (Fp) were calculated. Kidney biopsies in 26 patients were analyzed for allograft pathology, ie, acute tubular injury, inflammation, edema, renal fibrosis, and rejection. Histological results were correlated with MRI parameters. RESULTS: In the renal medulla FA (0.25 ± 0.06 vs. 0.29 ± 0.06, P < 0.01) and ADCmono (1.73 ± 0.13*10(-3) vs. 1.93 ± 0.16*10(-3) mm(2) /s, P < 0.001) were significantly reduced in DGF patients compared with patients with initial function. For ADCdiff and Fp similar reductions were observed. FA and ADCmono significantly correlated with renal function (r = 0.53 and r = 0.57, P < 0.001) and were inversely correlated with the amount of renal fibrosis (r = -0.63 and r = -0.65, P < 0.05). CONCLUSION: Combined DTI and DWI detected allograft dysfunction early after kidney transplantation and correlated with allograft fibrosis. J. Magn. Reson. Imaging 2016;44:112-121.

Functional MRI detects perfusion impairment in renal allografts with delayed graft function.

Delayed graft function (DGF) after kidney transplantation is not uncommon, and it is associated with long-term allograft impairment. Our aim was to compare renal perfusion changes measured with noninvasive functional MRI in patients early after kidney transplantation to renal function and allograft histology in biopsy samples. Forty-six patients underwent MRI 4-11 days after transplantation. Contrast-free MRI renal perfusion images were acquired using an arterial spin labeling technique. Renal function was assessed by estimated glomerular filtration rate (eGFR), and renal biopsies were performed when indicated within 5 days of MRI. Twenty-six of 46 patients had DGF. Of these, nine patients had acute rejection (including borderline), and eight had other changes (e.g., tubular injury or glomerulosclerosis). Renal perfusion was significantly lower in the DGF group compared with the group with good allograft function (231 ± 15 vs. 331 ± 15 ml·min(-1)·100 g(-1), P < 0.001). Living donor allografts exhibited significantly higher perfusion values compared with deceased donor allografts (P < 0.001). Renal perfusion significantly correlated with eGFR (r = 0.64, P < 0.001), resistance index (r = -0.57, P < 0.001), and cold ischemia time (r = -0.48, P < 0.01). Furthermore, renal perfusion impairment early after transplantation predicted inferior renal outcome and graft loss. In conclusion, noninvasive functional MRI detects renal perfusion impairment early after kidney transplantation in patients with DGF.

Targeted MRI/TRUS fusion-guided biopsy in men with previous prostate biopsies using a novel registration software and multiparametric MRI PI-RADS scores: first results.

PURPOSE: To evaluate a novel system for MRI/TRUS fusion-guided biopsy for detection of prostate cancer (PCa) in patients with previous negative prostate biopsy and determine diagnostic accuracy when using the Prostate Imaging Reporting and Data System (PI-RADS) for multiparametric magnetic resonance imaging (mpMRI) as proposed by the European Society of Urogenital Radiology. METHODS: Thirty-nine men with clinical suspicion of PCa and history of previous prostate biopsy underwent mpMRI on a 3-T MRI. In total, 72 lesions were evaluated by the consensus of two radiologists. PI-RADS scores for each MRI sequence, the sum of the PI-RADS scores and the global PI-RADS were determined. MRI/TRUS fusion-guided targeted biopsy was performed using the BioJet™ software combined with a transrectal ultrasound system. Image fusion was based on rigid registration. PI-RADS scores of the dominant lesion were compared with histopathological results. Diagnostic accuracy was determined using receiver operating characteristic curve analysis. RESULTS: MRI/TRUS fusion-guided biopsy was reliable and successful for 71 out of 72 lesions. The global PI-RADS score of the dominant lesion was significantly higher in patients with PCa (4.0 ± 1.3) compared to patients with negative histopathology (2.6 ± 0.8; p = 0.0006). Using a global PI-RADS score cut-off ≥4, a sensitivity of 85 %, a specificity of 82 % and a negative predictive value of 92 % were achieved. CONCLUSIONS: The described fusion system is dependable and efficient for targeted MRI/TRUS fusion-guided biopsy. mpMRI PI-RADS scores combined with a novel real-time MRI/TRUS fusion system facilitate sufficient diagnosis of PCa with high sensitivity and specificity.

Acute kidney injury: arterial spin labeling to monitor renal perfusion impairment in mice-comparison with histopathologic results and renal function.

PURPOSE: To determine if arterial spin-labeling (ASL) magnetic resonance (MR) imaging can show serial changes in renal perfusion in mice with ischemia-induced acute kidney injury (AKI) and to compare imaging results with those of renal histologic examination and inulin and para-aminohippuric acid (PAH) clearance. MATERIALS AND METHODS: In this animal care committee-approved study, AKI was induced in C57Bl/6 mice (n = 26) by clamping the right renal pedicle for 35 minutes for moderate (n = 16) or 45 minutes (n = 11) for severe AKI. Renal perfusion was measured in 10 animals with moderate and seven animals with severe AKI before and at five time points 1-28 days after surgery by using ASL with a 7-T MR imaging unit. Kidney volume loss and histologic evidence of acute tubular injury were assessed. Inulin and PAH clearance was determined in four animals with moderate and six animals with severe AKI to evaluate renal function and plasma flow for statistical analysis. Repeated measures analysis of variance, unpaired t tests, and correlation analysis were used. RESULTS: Renal perfusion values at day 7 were significantly reduced after moderate (56% ± 8; P < .01) and severe (33% ± 6; P < .001) AKI compared with presurgery values. Renal perfusion had returned to baseline levels at day 21 after moderate (96% ± 14) and remained compromised until day 28 after severe (46 % ± 9; P < .05) AKI. At day 28, for moderate versus severe AKI, kidney volume (84% ± 6 vs 60% ± 5; P < .05), degree of tubular injury (5.6% ± 1.8 vs 15.8% ± 2.4; P < .01), and inulin and para-aminohippuric acid clearance (47.5 µL/min ± 5.6 vs 7.3 µL/min ± 2.7; P < .001 and 100.8 µL/min ± 24.3 vs 4.8 µL/min ± 1.0; P < .001, respectively) were significantly different. Relative renal perfusion at days 7-28 significantly correlated with kidney volume loss (P < .01) and tubular injury (P < .05) 4 weeks after AKI. CONCLUSION: ASL allows evaluation of renal perfusion impairment associated with kidney volume loss and histologic changes after AKI in mice and may serve as a noninvasive biomarker for AKI.

T1-mapping for assessment of ischemia-induced acute kidney injury and prediction of chronic kidney disease in mice.

OBJECTIVES: To investigate whether T1-mapping allows assessment of acute kidney injury (AKI) and prediction of chronic kidney disease (CKD) in mice. METHODS: AKI was induced in C57Bl/6N mice by clamping of the right renal pedicle for 35 min (moderate AKI, n = 26) or 45 min (severe AKI, n = 23). Sham animals served as controls (n = 9). Renal histology was assessed in the acute (day 1 + day 7; d1 + d7) and chronic phase (d28) after AKI. Furthermore, longitudinal MRI-examinations (prior to until d28 after surgery) were performed using a 7-Tesla magnet. T1-maps were calculated from a fat-saturated echoplanar inversion recovery sequence, and mean and relative T1-relaxation times were determined. RESULTS: Renal histology showed severe tubular injury at d1 + d7 in both AKI groups, whereas, at d28, only animals with prolonged 45-min ischemia showed persistent signs of AKI. Following both AKI severities T1-values significantly increased and peaked at d7. T1-times in the contralateral kidney without AKI remained stable. At d7 relative T1-values in the outer stripe of the outer medulla were significantly higher after severe than after moderate AKI (138 ± 2% vs. 121 ± 3%, p = 0.001). T1-elevation persisted until d28 only after severe AKI. Already at d7 T1 in the outer stripe of the outer medulla correlated with kidney volume loss indicating CKD (r = 0.83). CONCLUSION: T1-mapping non-invasively detects AKI severity in mice and predicts further outcome. KEY POINTS: Renal T1-relaxation times are increased after ischemia-induced acute kidney injury. Renal T1-values correlate with subsequent kidney volume loss. T1-mapping detects the severity of acute kidney injury and predicts further outcome.

MR myocardial perfusion imaging: insights on techniques, analysis, interpretation, and findings.

Coronary microcirculatory dysfunction has a fundamental role in the pathophysiology of ischemic coronary artery disease (CAD) as well as various other cardiovascular disorders. Invasive coronary angiography remains the standard of reference for diagnosis of CAD. Nevertheless, it has been well acknowledged that the degree of luminal narrowing of epicardial coronary lesions detected at angiography is a poor predictor of the functional severity of the lesion. Recent studies demonstrate that assessment of coronary microcirculatory function by means of noninvasive myocardial perfusion imaging helps increase diagnostic accuracy and guide medical decision-making. Among available diagnostic modalities, cardiac magnetic resonance (MR) perfusion imaging has evolved to become a reliable and robust tool providing accurate quantitative assessment of regional myocardial perfusion. Owing to its high spatial resolution, noninvasive nature, and absence of ionizing radiation, cardiac MR perfusion imaging has improved detection of clinically relevant CAD. It has also offered further insights into the understanding of various cardiovascular disorders resulting from coronary microvascular dysfunction in the absence of proximal flow-limiting CAD. Cardiac MR perfusion imaging is now routinely used in many centers and shows promise in evaluating patients with disorders beyond those of the epicardial coronary circulation. Recent implementation of high-field-strength magnets and rapid acquisition techniques have further contributed to expanding the role of cardiac MR perfusion imaging to include novel promising applications. In this article, we provide an overview of cardiac MR perfusion imaging, including techniques, image analysis, and clinical applications.

3D-MRCP for evaluation of intra- and extrahepatic bile ducts: comparison of different acquisition and reconstruction planes.

BACKGROUND: Magnetic resonance cholangiopancreatography (MRCP) is an established technique for the evaluation of intra- and extrahepatic bile ducts in patients with known or suspected hepatobiliary disease. However, the ideal acquisition and reconstruction plane for optimal bile duct evaluation with 3D technique has not been evaluated. The purpose of our study was to compare different acquisition and reconstruction planes of 3D-MRCP for bile duct assessment. METHODS: 34 patients (17f/17 m, mean age 41y) referred for MRCP were included in this prospective IRB-approved study. Respiratory-triggered 3D-T2w-MRCP sequences were acquired in coronal and axial plane. Coronal and axial MIP were reconstructed based on each dataset (resulting in two coronal and two axial MIP, respectively). Three readers in two sessions independently assessed the MIP, regarding visualization of bile ducts and image quality. Results were compared (Wilcoxon test). Intra- and interobserver variability were calculated (kappa-statistic). RESULTS: In case of coronal data acquisition, visualization of bile duct segments was significantly better on coronal reconstructed MIP images as compared to axial reconstructed MIP (p < 0.05). Regarding visualization, coronal MIP of the coronal acquisition were equal to coronal MIP of the axial acquisition (p > 0.05). Image quality of coronal and axial datasets did not differ significantly. Intra- and interobserver agreement regarding bile duct visualization were moderate to excellent (κ-range 0.55-1.00 and 0.42-0.85, respectively). CONCLUSIONS: The results of our study suggest that for visualization and evaluation of intra- and extrahepatic bile duct segments reconstructed images in coronal orientation are preferable. The orientation of the primary dataset (coronal or axial) is negligible.

Assessment of impaired vascular reactivity in a rat model of diabetic nephropathy: effect of nitric oxide synthesis inhibition on intrarenal diffusion and oxygenation measured by magnetic resonance imaging.

Diabetes is associated with impaired vascular reactivity and the development of diabetic nephropathy. In a rat model of streptozotocin-induced diabetic nephropathy, the effects of systemic nitric oxide (NO) synthesis inhibition on intrarenal diffusion and oxygenation were determined by noninvasive magnetic resonance diffusion tensor imaging and blood O2 level-dependent (BOLD) imaging, respectively. Eight weeks after the induction of diabetes, 21 rats [n = 7 rats each in the untreated control group, diabetes mellitus (DM) group, and DM with uninephrectomy (DM UNX) group] were examined by MRI. Diffusion tensor imaging and BOLD sequences were acquired before and after NO synthesis inhibition with N-nitro-L-arginine methyl ester (L-NAME). In the same rats, mean arterial pressure and vascular conductance were determined with and without the influence of L-NAME. In control animals, NO synthesis inhibition was associated with a significant increase of mean arterial pressure of 33.8 ± 4.3 mmHg (P < 0.001) and a decrease of vascular conductance of -17.8 ± 2.0 µl·min(-1)·100 mmHg(-1) (P < 0.001). These changes were attenuated in both DM and DM UNX groups with no significant difference between before and after L-NAME measurements in DM UNX animals. Similarly, L-NAME challenge induced a significant reduction of renal transverse relaxation time (T2*) at MRI in control animals, indicating reduced renal oxygenation after L-NAME injection compared with baseline. DM UNX animals did not show a significant T2* reduction after NO synthesis inhibition in the renal cortex and attenuated T2* reduction in the outer medulla. MRI parameters of tissue diffusion were not affected by L-NAME in all groups. In conclusion, BOLD imaging proved valuable to noninvasively measure renal vascular reactivity upon NO synthesis inhibition in control animals and to detect impaired vascular reactivity in animals with diabetic nephropathy.

Cardiovascular risk in bipolar disorder - A case for the hypothalamus-pituitary-adrenal axis?

BACKGROUND: Unipolar major depressive disorder (MDD) and bipolar disorder (BD) are associated with elevated mortality risk secondary to natural causes. Cardiovascular disease (CVD) constitutes the most prevalent underlying condition. Patients with BD display higher CVD-associated excess mortality than MDD patients. Epicardial adipose tissue (EAT) volume, a known predictor of premature CV morbidity and adrenal gland (AG) volume, an indicator for chronic hypothalamus-pituitary-adrenal (HPA) axis activation, were compared in BD and MDD patients. METHODS: Magnetic resonance imaging was performed to assess EAT and AG volume in age-, gender-, and body mass index (BMI)-matched MDD (N = 27) and BD (N = 27) patients. Ten-year CV mortality risk and diabetes risk were assessed by PROCAM, ESC-SCORE, and FINDRISK, respectively; metabolic syndrome (MetS) was determined following NCEP/ATP III criteria. RESULTS: Cardiometabolic risk scores and frequency of MetS were comparable, and scores of cardiometabolic risk indices did not significantly differ in both groups. After adjustment for age, BMI, and physical activity, EAT and AG volumes were significantly higher in BD compared to MDD. Partial correlation analyses showed a significant positive association of EAT and AG volumes in BD but not in the MDD. LIMITATIONS: The modest sample size warrants confirmation in a larger cohort and the cross-sectional design does not allow for temporal or causal inferences. CONCLUSION: Our study indicates increased EAT accumulation in BD patients. This was associated with HPA axis dysregulation. Therapeutic lifestyle interventions that reduce EAT volume should be considered in clinical BD management.

Stabilizing A Vascularized Autologous Matrix with Flexible Magnesium Scaffolds to Reconstruct Dysfunctional Left Ventricular Myocardium in a Large-Animal Feasibility Study.

The surgical reconstruction of dysfunctional myocardium is necessary for patients with severe heart failure. Autologous biomaterials, such as vascularized patch materials, have a regenerative potential due to in vivo remodeling. However, additional temporary mechanical stabilization of the biomaterials is required to prevent aneurysms or rupture. Degradable magnesium scaffolds could prevent these life-threatening risks. A left ventricular transmural defect was reconstructed in minipigs with a piece of the autologous stomach. Geometrically adaptable and degradable scaffolds made of magnesium alloy LA63 were affixed on the epicardium to stabilize the stomach tissue. The degradation of the magnesium structures, their biocompatibility, physiological remodeling of the stomach, and the heart's function were examined six months after the procedure via MRI (Magnetic Resonance Imaging), angiography, µ-CT, and light microscopy. All animals survived the surgery. Stable physiological integration of the stomach patch could be detected. No ruptures of the grafts occurred. The magnesium scaffolds showed good biocompatibility. Regenerative surgical approaches for treating severe heart failure are a promising therapeutic alternative to the currently available, far from optimal options. The temporary mechanical stabilization of viable, vascularized grafts facilitates their applicability in clinical scenarios.

Whole-body diffusion-weighted MRI in a case of Rosai-Dorfman disease with exclusive multifocal skeletal involvement.

Rosai-Dorfman disease (RDD) is a rare disorder and usually presents with painless bilateral cervical lymphadenopathy. About 43% of RDD patients show extranodal involvement, including bones (8%). As RDD is a systemic disease, which can involve lymph nodes, bones, skin, kidneys, respiratory tract, parotid gland, orbital cavity and the central nervous system, whole-body imaging may be useful for the assessment of extent, distribution and follow-up of disease. Whole-body diffusion-weighted MRI is able to demonstrate lesions and to assess therapy response without the need for radiation or intravenous contrast agent. Here, we report a case of a 15-year-old boy with primary skeletal RDD without lymphadenopathy, who was staged and followed by whole-body diffusion-weighted MRI.

Adipose Tissue Compartments, Inflammation, and Cardiovascular Risk in the Context of Depression.

The neurobiological and behavioral underpinnings linking mental disorders, in particular, major depressive disorder (MDD), with cardiovascular disorders are a matter of debate. Recent research focuses on visceral (intra-abdominal and epicardial) adipose tissue and inflammation and their impact on the development of cardiometabolic disorders. Intra-abdominal adipose tissue is defined as an endocrine active fat compartment surrounding inner organs and is associated with type 2 diabetes mellitus, a risk factor for the later development of cardiovascular disorders. Epicardial (pericardial) adipose tissue is a fat compartment surrounding the heart with close proximity to the arteries supporting the heart. Visceral adipose tissue (VAT) is an important source of inflammatory mediators that, in concert with other risk factors, plays a leading role in cardiovascular diseases. In conjunction with the behavioral (physical inactivity, sedentary lifestyle), psychological (adherence problems), and hormonal (dysfunction of the hypothalamus-pituitary-adrenal axis with subsequent hypercortisolism) alterations frequently accompanying MDD, an enhanced risk for cardiovascular disorders results.

Diffusion Weighted Imaging and T2 Mapping Detect Inflammatory Response in the Renal Tissue during Ischemia Induced Acute Kidney Injury in Different Mouse Strains and Predict Renal Outcome.

To characterize ischemia reperfusion injury (IRI)-induced acute kidney injury (AKI) in C57BL/6 (B6) and CD1-mice by longitudinal functional MRI-measurement of edema formation (T2-mapping) and inflammation (diffusion weighted imaging (DWI)). IRI was induced with unilateral right renal pedicle clamping for 35min. 7T-MRI was performed 1 and 14 days after surgery. DWI (7 b-values) and multiecho TSE sequences (7 TE) were acquired. Parameters were quantified in relation to the contralateral kidney on day 1 (d1). Renal MCP-1 and IL-6-levels were measured by qPCR and serum-CXCL13 by ELISA. Immunohistochemistry for fibronectin and collagen-4 was performed. T2-increase on d1 was higher in the renal cortex (127 ± 5% vs. 94 ± 6%, p < 0.01) and the outer stripe of the outer medulla (141 ± 9% vs. 111 ± 9%, p < 0.05) in CD1, indicating tissue edema. Medullary diffusivity was more restricted in CD1 than B6 (d1: 73 ± 3% vs. 90 ± 2%, p < 0.01 and d14: 77 ± 5% vs. 98 ± 3%, p < 0.01). Renal MCP-1 and IL-6-expression as well as systemic CXCL13-release were pronounced in CD1 on d1 after IRI. Renal fibrosis was detected in CD1 on d14. T2-increase and ADC-reduction on d1 correlated with kidney volume loss on d14 (r = 0.7, p < 0.05; r = 0.6, p < 0.05) and could serve as predictive markers. T2-mapping and DWI evidenced higher susceptibility to ischemic AKI in CD1 compared to B6.

Diffusion-Weighted Imaging and Mapping of T1 and T2 Relaxation Time for Evaluation of Chronic Renal Allograft Rejection in a Translational Mouse Model.

We hypothesized that multiparametric MRI is able to non-invasively assess, characterize and monitor renal allograft pathology in a translational mouse model of chronic allograft rejection. Chronic rejection was induced by allogenic kidney transplantation (ktx) of BALB/c-kidneys into C57BL/6-mice (n = 23). Animals after isogenic ktx (n = 18) and non-transplanted healthy animals (n = 22) served as controls. MRI sequences (7T) were acquired 3 and 6 weeks after ktx and quantitative T1, T2 and apparent diffusion coefficient (ADC) maps were calculated. In addition, in a subset of animals, histological changes after ktx were evaluated. Chronic rejection was associated with a significant prolongation of T1 time compared to isogenic ktx 3 (1965 ± 53 vs. 1457 ± 52 ms, p < 0.001) and 6 weeks after surgery (1899 ± 79 vs. 1393 ± 51 ms, p < 0.001). While mean T2 times and ADC were not significantly different between allogenic and isogenic kidney grafts, histogram-based analysis of ADC revealed significantly increased tissue heterogeneity in allografts at both time points (standard derivation/entropy/interquartile range, p < 0.05). Correspondingly, histological analysis showed severe inflammation, graft fibrosis and tissue heterogeneity in allogenic but not in isogenic kidney grafts. In conclusion, renal diffusion weighted imaging and mapping of T2 and T1 relaxation times enable detection of chronic renal allograft rejection in mice. The combined quantitative assessment of mean values and histograms provides non-invasive information of chronic changes in renal grafts and allows longitudinal monitoring.

Application of MR diffusion imaging for non-invasive assessment of acute kidney injury after lung transplantation.

To assess whether MR diffusion imaging may be applied for non-invasive detection of renal changes correlating with clinical diagnosis of acute kidney injury (AKI) in patients after lung transplantation (lutx).Fifty-four patients (mean age 49.6, range 26-64 years) after lutx were enrolled in a prospective clinical study and underwent functional MR imaging of the kidneys in the early postoperative period. Baseline s-creatinine ranged from 39 to 112 µmol/L. For comparison, 14 healthy volunteers (mean age 42.1, range 24-59 years) underwent magnetic resonance imaging (MRI) using the same protocol. Renal tissue injury was evaluated using quantification of diffusion and diffusion anisotropy with diffusion-weighted (DWI) and diffusion-tensor imaging (DTI). Renal function was monitored and AKI was defined according to Acute-Kidney-Injury-Network criteria. Statistical analysis comprised one-way ANOVA and Pearson correlation.67% of lutx patients (36/54) developed AKI, 47% (17/36) had AKI stage 1, 42% (15/36) AKI stage 2, and 8% (3/36) severe AKI stage 3. Renal apparent diffusion coefficients (ADCs) were reduced in patients with AKI, but preserved in transplant patients without AKI and healthy volunteers (2.07 ±â€Š0.02 vs 2.18 ±â€Š0.05 vs 2.21 ±â€Š0.03 × 10 mm/s, P < .05). Diffusion anisotropy was reduced in all lutx recipients compared with healthy volunteers (AKI: 0.27 ±â€Š0.01 vs no AKI: 0.28 ±â€Š0.01 vs healthy: 0.33 ±â€Š0.02; P < .01). Reduction of renal ADC correlated significantly with acute loss of renal function after lutx (decrease of renal function in the postoperative period and glomerular filtration rate on the day of MRI).MR diffusion imaging enables non-invasive assessment of renal changes correlating with AKI early after lutx. Reduction of diffusion anisotropy was present in all patients after lutx, whereas marked reduction of renal ADC was observed only in the group of lutx recipients with AKI and correlated with renal function impairment.