Lifelong endurance exercise and its relation with coronary atherosclerosis.

AIMS: The impact of long-term endurance sport participation (on top of a healthy lifestyle) on coronary atherosclerosis and acute cardiac events remains controversial. METHODS AND RESULTS: The Master@Heart study is a well-balanced prospective observational cohort study. Overall, 191 lifelong master endurance athletes, 191 late-onset athletes (endurance sports initiation after 30 years of age), and 176 healthy non-athletes, all male with a low cardiovascular risk profile, were included. Peak oxygen uptake quantified fitness. The primary endpoint was the prevalence of coronary plaques (calcified, mixed, and non-calcified) on computed tomography coronary angiography. Analyses were corrected for multiple cardiovascular risk factors. The median age was 55 (50-60) years in all groups. Lifelong and late-onset athletes had higher peak oxygen uptake than non-athletes [159 (143-177) vs. 155 (138-169) vs. 122 (108-138) % predicted]. Lifelong endurance sports was associated with having ≥1 coronary plaque [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.17-2.94], ≥ 1 proximal plaque (OR 1.96, 95% CI 1.24-3.11), ≥ 1 calcified plaques (OR 1.58, 95% CI 1.01-2.49), ≥ 1 calcified proximal plaque (OR 2.07, 95% CI 1.28-3.35), ≥ 1 non-calcified plaque (OR 1.95, 95% CI 1.12-3.40), ≥ 1 non-calcified proximal plaque (OR 2.80, 95% CI 1.39-5.65), and ≥1 mixed plaque (OR 1.78, 95% CI 1.06-2.99) as compared to a healthy non-athletic lifestyle. CONCLUSION: Lifelong endurance sport participation is not associated with a more favourable coronary plaque composition compared to a healthy lifestyle. Lifelong endurance athletes had more coronary plaques, including more non-calcified plaques in proximal segments, than fit and healthy individuals with a similarly low cardiovascular risk profile. Longitudinal research is needed to reconcile these findings with the risk of cardiovascular events at the higher end of the endurance exercise spectrum.

Left Main Coronary Artery Compression in Pulmonary Hypertension: Value of Multimodality Imaging in Diagnosis and Treatment.

Left main coronary artery (LMCA) extrinsic compression should be suspected in patients with pulmonary hypertension and angina. Coronary angiography and intracoronary imaging are complementary techniques to confirm the diagnosis and guide therapy. In the largest prospective single-center series, the prevalence of a significant LMCA stenosis >50% due to dilated pulmonary artery-induced extrinsic compression was 6% in the pulmonary arterial hypertension population, and increased to 40% in patients with angina-like symptoms.

PURSUING OPTIMAL RADIATION DOSE IN PEDIATRIC CARDIAC CT: A REPORT FROM UNIVERSITY HOSPITAL LEUVEN.

BACKGROUND: Computed tomography (CT) balances between high resolution and low radiation dose. Given the greater radiosensitivity of children, it is appropriate to use child-friendly CT-protocols that reduce radiation dose at acceptable image quality.This article states the radiation dose in pediatric cardiac CT-examinations at university hospital Leuven (Belgium) and compares with findings published by similar medical centers. The diagnostic accuracy was simultaneously compared, as it correlates with radiation dose. MATERIAL AND METHODS: his retrospective observational study analyzed 58 CT-scans of 52 patients. The radiation dose was calculated in effective dose. The image quality was scored qualitatively with a 5-point scale. The diagnostic accuracy, a derivative representation of the image quality, was checked with findings from surgery or conventional angiography. RESULTS: The mean effective dose in our study population was 1.3 ± 0.4 mSv. The qualitative image quality was on average 'good', elaborated with a score of 4.0 ± 0.2. The diagnostic accuracy was 92%. Comparative literature study provides a mean effective dose of 1.5 mSv and the reported diagnostic accuracy from other centers reaches ≥90%. CONCLUSIONS: At our center pediatric cardiac CT-scans are obtained with good-to-excellent image quality and high diagnostic accuracy at low radiation doses. These results meet the radiation dose and diagnostic accuracy as published by comparable medical centers.

Factors predicting long-term outcomes of percutaneous angioplasty and stenting of the superior mesenteric artery for chronic mesenteric ischemia.

Background: To analyse the long-term outcomes of percutaneous angioplasty and stenting of the superior mesenteric artery (SMA) in the treatment of chronic mesenteric ischemia (CMI), and to assess predictive factors for a better clinical outcome. Patients and methods: Retrospective analysis of 76 consecutive patients, treated percutaneously for CMI between January 1999 and January 2018 and followed up until the end of 2018. Patients' pre-, peri- and post-interventional clinical and radiological data were gathered from the institutional electronic medical records. The Kaplan Meier method with log rank test or the Cox model were used to analyse overall survival; the cumulative incidence function with Pepe and Mori test or the Fine and Grey model were used to analyse relapse-free survival, considering death as a competing event. Results: Seventy-six consecutive patients with a mean age of 72 years were included in the study. Catheter-angiography revealed an ostial or non-ostial >90% stenosis in n=23 (29.7%) and n=53 (69.7%) of included patients, respectively. Immediate clinical success was achieved in n=68 (89.5%), and procedural complications were observed in n=13 (17.1%) patients. Long-term follow-up revealed relapse of symptoms in n=21 (28.8%) patients, and overall survival estimates are 81.8%, 57.0% and 28.2% after two, five and ten years of follow-up, respectively. A trend towards longer relapse-free survival was found in the circumferential stenosis group (78.2% at five years) compared with the non-circumferential stenosis group (55.5%) (P=0.063). Conclusions: Angioplasty and stenting of the SMA for CMI is relatively safe and effective despite a substantial number of patients experiencing clinical relapse over time. Patients with focal, circumferential stenosis might have longer relapse-free survival than patients with non-circumferential stenosis.

Endurance exercise and the risk of cardiovascular pathology in men: a comparison between lifelong and late-onset endurance training and a non-athletic lifestyle - rationale and design of the Master@Heart study, a prospective cohort trial.

INTRODUCTION: Low and moderate endurance exercise is associated with better control of cardiovascular risk factors, a decreased risk of coronary artery disease and atrial fibrillation (AF). There is, however, a growing proportion of individuals regularly performing strenuous and prolonged endurance exercise in which the health benefits have been challenged. Higher doses of endurance exercise have been associated with a greater coronary atherosclerotic plaque burden, risk of AF and myocardial fibrosis (MF). METHODS AND ANALYSIS: Master@Heart is a multicentre prospective cohort study aiming to assess the incidence of coronary atherosclerosis, AF and MF in lifelong endurance athletes compared to late-onset endurance athletes (initiation of regular endurance exercise after the age of 30 years) and healthy non-athletes.The primary endpoint is the incidence of mixed coronary plaques. Secondary endpoints include coronary calcium scores, coronary stenosis >50%, the prevalence of calcified and soft plaques and AF and MF presence. Tertiary endpoints include ventricular arrhythmias, left and right ventricular function at rest and during exercise, arterial stiffness and carotid artery intima media thickness.Two hundred male lifelong athletes, 200 late-onset athletes and 200 healthy non-athletes aged 45-70 will undergo comprehensive cardiovascular phenotyping using CT, coronary angiography, echocardiography, cardiac MRI, 12-lead ECG, exercise ECG and 24-hour Holter monitoring at baseline. Follow-up will include online tracking of sports activities, telephone calls to assess clinical events and a 7-day ECG recording after 1 year. ETHICS AND DISSEMINATION: Local ethics committees approved the Master@Heart study. The trial was launched on 18 October 2018, recruitment is complete and inclusions are ongoing. TRIAL REGISTRATION NUMBER: NCT03711539.

An automated framework for localization, segmentation and super-resolution reconstruction of fetal brain MRI.

High-resolution volume reconstruction from multiple motion-corrupted stacks of 2D slices plays an increasing role for fetal brain Magnetic Resonance Imaging (MRI) studies. Currently existing reconstruction methods are time-consuming and often require user interactions to localize and extract the brain from several stacks of 2D slices. We propose a fully automatic framework for fetal brain reconstruction that consists of four stages: 1) fetal brain localization based on a coarse segmentation by a Convolutional Neural Network (CNN), 2) fine segmentation by another CNN trained with a multi-scale loss function, 3) novel, single-parameter outlier-robust super-resolution reconstruction, and 4) fast and automatic high-resolution visualization in standard anatomical space suitable for pathological brains. We validated our framework with images from fetuses with normal brains and with variable degrees of ventriculomegaly associated with open spina bifida, a congenital malformation affecting also the brain. Experiments show that each step of our proposed pipeline outperforms state-of-the-art methods in both segmentation and reconstruction comparisons including expert-reader quality assessments. The reconstruction results of our proposed method compare favorably with those obtained by manual, labor-intensive brain segmentation, which unlocks the potential use of automatic fetal brain reconstruction studies in clinical practice.

Fetal MRI for dummies: what the fetal medicine specialist should know about acquisitions and sequences.

Fetal MRI is an increasingly used tool in the field of prenatal diagnosis. While US remains the first line screening tool, as an adjuvant imaging tool, MRI has been proven to increase diagnostic accuracy and change patient counseling. Further, there are instances when US may not be sufficient for diagnosis. As a multidisciplinary field, it is important that every person involved in the referral, diagnosis, counseling and treatment of the patients is familiar with the basic principles, indications and findings of fetal MRI. The purpose of the current paper is to equip radiologists and non-radiologists with basic MRI principles and essential topics in patient preparation and provide illustrative examples of when fetal MRI may be used. This aims to aid the referring clinician in better selecting and improve patient counseling prior to arrival in the radiology department and, ultimately, patient care.

Heart Rate Reserve in Fontan Patients: Chronotropic Incompetence or Hemodynamic Limitation?

Background Patients with a Fontan circulation achieve lower peak heart rates ( HR ) during exercise. Whether this impaired chronotropic response reflects pathology of the sinoatrial node or is a consequence of altered cardiac hemodynamics is uncertain. We evaluated the adequacy of HR acceleration throughout exercise relative to metabolic demand and cardiac output in patients with a Fontan circulation relative to healthy controls. Methods and Results Thirty subjects (20 healthy controls and 10 Fontan patients) underwent cardiac magnetic resonance imaging with simultaneous invasive pressure recording via a pulmonary and radial artery catheter during supine bicycle exercise to near maximal exertion. Adequacy of cardiac index, stroke volume, and HR reserve was assessed by determining the exercise-induced increase (∆) in cardiac index, stroke volume, and HR relative to the increase in oxygen consumption ( VO 2). HR reserve was lower in Fontan patients compared with controls (71±21 versus 92±15 bpm; P=0.001). In contrast, increases in HR relative to workload and VO 2 were higher than in controls. The change in cardiac index relative to the change in VO 2 (∆cardiac index/∆ VO 2) was similar between groups, but Fontan patients had increased ∆ HR /∆ VO 2 and reduced ∆ stroke volume/∆ VO 2 compared with controls. There was an early and marked reduction in stroke volume during exercise in Fontan patients corresponding with a plateau in cardiac output at a low peak HR . Conclusions In Fontan patients, the chronotropic response is appropriate relative to exercise intensity, implying normal sinoatrial function. However, premature reductions in ventricular filling and stroke volume cause an early plateau in cardiac output beyond which further increases in HR would be physiologically implausible. Thus, abnormal cardiac filling rather than sinoatrial node dysfunction explains the diminished HR reserve in Fontan patients.

Conservative treatment of non-aneurysmal infectious aortitis: a case report and review of the literature.

BACKGROUND:  Non-aneurysmal infectious aortitis is a rare clinical entity with most often lethal complications when surgical intervention is delayed. OBJECTIVES:  This report describes the case of a non-aneurysmal infectious aortitis complicated with a penetrating aortic ulcer in an elderly woman, caused by a methicillin-sensitive Staphylococcus aureus. Surgery was deemed contra-indicated and treatment was limited to the administration of intravenous vancomycin (2 grams daily), followed by flucloxacillin (6 times 2 grams daily). She remains well after one year. METHODS: The Internet databases Medline and Embase were searched. Articles were selected based on relevanceof abstract, article type and impact of the journal. RESULTS:  A literature review addresses current insights in the pathogenesis, diagnosis, and treatment of non-aneurysmal infectious aortitis.

Exercise cardiac magnetic resonance to differentiate athlete's heart from structural heart disease.

Aims: The distinction between left ventricular (LV) dilation with mildly reduced LV ejection fraction (EF) in response to regular endurance exercise training and an early cardiomyopathy is a frequently encountered and difficult clinical conundrum. We hypothesized that exercise rather than resting measures would provide better discrimination between physiological and pathological LV remodelling and that preserved exercise capacity does not exclude significant LV damage. Methods and results: We prospectively included 19 subjects with LVEF between 40 and 52%, comprising 10 ostensibly healthy endurance athletes (EA-healthy) and nine patients with dilated cardiomyopathy (DCM). In addition, we recruited five EAs with a region of subepicardial LV. Receiver operating characteristic fibrosis (EA-fibrosis). Cardiac magnetic resonance (CMR) imaging was performed at rest and during supine bicycle exercise. Invasive afterload measures were obtained to enable calculations of biventricular function relative to load (an estimate of contractility). In DCM and EA-fibrosis subjects there was diminished augmentation of LVEF (5 ± 6% vs. 4 ± 3% vs. 14 ± 3%; P = 0.001) and contractility [LV end-systolic pressure-volume ratio, LVESPVR; 1.4 (1.3-1.6) vs. 1.5 (1.3-1.6) vs. 1.8 (1.7-2.7); P < 0.001] during exercise relative to EA-healthy. Receiver-operator characteristic curves demonstrated that a cut-off value of 11.2% for ΔLVEF differentiated DCM and EA-fibrosis patients from EA-healthy [area under the curve (AUC) = 0.92, P < 0.001], whereas resting LVEF and VO2max were not predictive. The AUC value for LVESPVR ratio was similar to that of ΔLVEF. Conclusions: Functional cardiac evaluation during exercise is a promising tool in differentiating healthy athletes with borderline LVEF from those with an underlying cardiomyopathy. Excellent exercise capacity does not exclude significant LV damage.

Visualization, Quantification and Characterization of Caerulein-Induced Acute Pancreatitis in Rats by 3.0T Clinical MRI, Biochemistry and Histomorphology.

Purpose: To investigate whether Caerulein-induced acute pancreatitis (AP) in rats could be noninvasively studied by clinical magnetic resonance imaging (MRI) techniques and validated by enzymatic biochemistry and histomorphology. Materials and Methods: The study was approved by the institutional animal ethical committee. The AP was induced in 26 rats by intraperitoneal injections of Caerulein, as compared to 6 normal rats. T2-weighted 3D MRI, T2 relaxation measurement and contrast enhanced T1-weighted MRI were performed at 3 Tesla. Pancreatic volume and contrast ratio of pancreas against surrounding tissues were measured by MRI. Animals were scarified at 3, 8, 24 and 48-hr respectively for analyses of serum lipase and amylase levels, and biliopancreatic perfusion-assisted histomorphology. Results: The AP could be observed on MRI 3-hr onwards after Caerulein-administration. T2 relaxation within the pancreas was prolonged due to high water content or edema. Increase of vascular permeability was indicated by T1 contrast enhancement. Both edema and vascular permeability gradually recovered afterwards (p<0.05/0.01), paralleled by declining serum enzyme levels (p<0.05). Microscopy revealed cell vacuolization and edema for early stage, and increased inflammatory cell infiltration and acinar cell loss after 24 and 48-hr. Conclusion: Multiparametric MRI techniques at 3.0T could facilitate noninvasive diagnosis and characterization of Caerulein induced AP in rats, as validated by a novel ex vivo method.

Right ventricular and pulmonary vascular reserve in asymptomatic BMPR2 mutation carriers.

BACKGROUND: Non-invasive estimates have suggested that asymptomatic BMPR2 mutation carriers may have an abnormal pulmonary vascular response to exercise and hypoxia. However, this has not been assessed with "gold standard" invasive measures. METHODS: Eight controls and 8 asymptomatic BMPR2 mutation carriers underwent cardiac magnetic resonance imaging with simultaneous invasive pressure recording during bicycle exercise in normoxia, hypoxia and after sildenafil administration. Abnormal pulmonary vascular reserve was defined as an increase in mean pulmonary artery pressure relative to cardiac output (P/Q slope) >3 mm Hg/liter/min. RESULTS: During normoxic exercise, BMPR2 mutation carriers had a similar P/Q slope when compared with healthy subjects. Only 1 of 8 BMPR2 mutation carriers had a P/Q slope >3 mm Hg/liter/min. During exercise in hypoxia, 3 of 8 BMPR2 mutation carriers had P/Q slopes >3 mm Hg/liter/min compared with none of the controls. Sildenafil decreased the P/Q slope both in controls and BMPR2 mutation carriers. The exercise-induced increase in right ventricular ejection fraction was similar between groups. None of the BMPR2 mutation carriers developed pulmonary arterial hypertension within 2 (range 1.3 to 2.8) years. CONCLUSIONS: The presence of a BMPR2 mutation, per se, is not associated with an abnormal pulmonary vascular and right ventricular functional response to exercise in asymptomatic individuals. Longer follow-up will be required to determine whether a P/Q slope of >3 mm Hg/liter/min during exercise in normoxia or hypoxia is a sign of pre-clinical disease expression.

Biomechanical Characterization of Ascending Aortic Aneurysms.

Ascending thoracic aortic aneurysms (ATAAs) are a silent disease, ultimately leading to dissection or rupture of the arterial wall. There is a growing consensus that diameter information is insufficient to assess rupture risk, whereas wall stress and strength provide a more reliable estimate. The latter parameters cannot be measured directly and must be inferred through biomechanical assessment, requiring a thorough knowledge of the mechanical behaviour of the tissue. However, for healthy and aneurysmal ascending aortic tissues, this knowledge remains scarce. This study provides the geometrical and mechanical properties of the ATAA of six patients with unprecedented detail. Prior to their ATAA repair, pressure and diameter were acquired non-invasively, from which the distensibility coefficient, pressure-strain modulus and wall stress were calculated. Uniaxial tensile tests on the resected tissue yielded ultimate stress and stretch values. Parameters for the Holzapfel-Gasser-Ogden material model were estimated based on the pre-operative pressure-diameter data and the post-operative stress-stretch curves from planar biaxial tensile tests. Our results confirmed that mechanical or geometrical information alone cannot provide sufficient rupture risk estimation. The ratio of physiological to ultimate wall stress seems a more promising parameter. However, wall stress estimation suffers from uncertainties in wall thickness measurement, for which our results show large variability, between patients but also between measurement methods. Our results also show a large strength variability, a value which cannot be measured non-invasively. Future work should therefore be directed towards improved accuracy of wall thickness estimation, but also towards the large-scale collection of ATAA wall strength data.

Characterization of a rat orthotopic pancreatic head tumor model using three-dimensional and quantitative multi-parametric MRI.

The purpose of this study was to investigate the reliability of 3D isotropic MRI and quantitative multi-parametric MRI characterization on an orthotopic pancreatic head tumor model in rats. 3D isotropic T2 -weighted MRI was performed as a routine for tumor longitudinal follow-up and volume estimation. Common bile duct diameter was measured from 3D multiplanar reconstruction. Quantitative multi-parametric measurements including pixel-wise T2 , T1 relaxivity, apparent diffusion coefficient (ADC) and apparent diffusion kurtosis mapping were performed twice throughout tumor growth. Semi-quantitative and quantitative analyses based on an extended Tofts model were applied to region-of-interest-based dynamic contrast-enhanced imaging, followed by contrast ratio measurement on standard contrast-enhanced imaging. Moreover, low-level texture-based analysis was inspected for T2 , T1 , ADC and contrast ratio measurements. Results indicated that multi-parametric MRI showed good reproducibility for tumor characterization; the measurements were not affected by tumor growth. Tumor growth was further confirmed with histology examinations. To conclude, state-of-the-art clinical MRI techniques were translated to this preclinical tumor model with high reliability, and have paved the way for translational oncology studies on this tumor model.

Accuracy of Echocardiography to Evaluate Pulmonary Vascular and RV Function During Exercise.

OBJECTIVES: The authors have compared exercise echocardiography and exercise cardiac magnetic resonance imaging with simultaneous invasive pressure registration (ExCMRip) for the assessment of pulmonary vascular and right ventricular (RV) function. BACKGROUND: Exercise echocardiography may enable early diagnosis of pulmonary vascular disease, but its accuracy is untested. METHODS: Exercise imaging was performed in 61 subjects (19 athletes, 9 healthy nonathletes, 8 healthy BMPR2 [bone morphogenetic protein receptor type II] mutation carriers, 5 patients with new or worsening dyspnea after acute pulmonary embolism, and 20 patients with chronic thromboembolic pulmonary hypertension). Echocardiographic variables included mean pulmonary artery pressure (mPAP) and systolic pulmonary artery pressure (sPAP), cardiac output (CO), RV fractional area change, tricuspid annular systolic excursion, and RV end-systolic pressure-area ratio as a surrogate measure of RV contractile reserve. ExCMRip provided measurements of CO, RV ejection fraction, mPAP, sPAP, and RV end-systolic pressure-volume ratio at rest and during exercise. Abnormal pulmonary vascular reserve was defined as mPAP/CO slope >3 mm Hg/l/min by ExCMRip. RESULTS: Echocardiographic determination of mPAP/CO was possible in 53 of 61 subjects (87%). mPAP/CO by echocardiography was higher than that obtained by ExCMRip (+0.9 mm Hg/l/min; 95% limits of agreement, -3.6 to 5.4), but enabled accurate identification of patients with abnormal pulmonary vascular reserve (area under the receiver-operating characteristic curve, 0.88 [95% confidence interval (CI): 0.77 to 1.00; p < 0.0001]). Simplified relationships between sPAP and exercise intensity had similar accuracy in identifying subjects with pulmonary vascular disease (area under the receiver-operating characteristic curve, 0.95 [95% CI: 0.88 to 1.01]; p < 0.0001). RV fractional area change by echocardiography correlated strongly with RV ejection fraction by ExCMRip, whereas a moderate correlation was found between tricuspid annular systolic excursion and RV ejection fraction. A moderate correlation was found between ratios of peak exercise to resting RV end-systolic pressure-area ratio and RV end-systolic pressure-volume ratio (r = 0.64; p < 0.0001). CONCLUSIONS: Echocardiographic estimates of RV and pulmonary vascular function are feasible during exercise and identify pathology with reasonable accuracy. They represent valid screening tools for the identification of pulmonary vascular disease in routine clinical practice.

Exercise-induced right ventricular dysfunction is associated with ventricular arrhythmias in endurance athletes.

AIMS: Intense exercise places disproportionate strain on the right ventricle (RV) which may promote pro-arrhythmic remodelling in some athletes. RV exercise imaging may enable early identification of athletes at risk of arrhythmias. METHODS AND RESULTS: Exercise imaging was performed in 17 athletes with RV ventricular arrhythmias (EA-VAs), of which eight (47%) had an implantable cardiac defibrillator (ICD), 10 healthy endurance athletes (EAs), and seven non-athletes (NAs). Echocardiographic measures included the RV end-systolic pressure-area ratio (ESPAR), RV fractional area change (RVFAC), and systolic tricuspid annular velocity (RV S'). Cardiac magnetic resonance (CMR) measures combined with invasive measurements of pulmonary and systemic artery pressures provided left-ventricular (LV) and RV end-systolic pressure-volume ratios (SP/ESV), biventricular volumes, and ejection fraction (EF) at rest and during intense exercise. Resting measures of cardiac function were similar in all groups, as was LV function during exercise. In contrast, exercise-induced increases in RVFAC, RV S', and RVESPAR were attenuated in EA-VAs during exercise when compared with EAs and NAs (P < 0.0001 for interaction group × workload). During exercise-CMR, decreases in RVESV and augmentation of both RVEF and RV SP/ESV were significantly less in EA-VAs relative to EAs and NAs (P < 0.01 for the respective interactions). Receiver-operator characteristic curves demonstrated that RV exercise measures could accurately differentiate EA-VAs from subjects without arrhythmias [AUC for ΔRVESPAR = 0.96 (0.89-1.00), P < 0.0001]. CONCLUSION: Among athletes with normal cardiac function at rest, exercise testing reveals RV contractile dysfunction among athletes with RV arrhythmias. RV stress testing shows promise as a non-invasive means of risk-stratifying athletes.

Three-dimensional contrasted visualization of pancreas in rats using clinical MRI and CT scanners.

The purpose of this work was to visualize the pancreas in post-mortem rats with local contrast medium infusion by three-dimensional (3D) magnetic resonance imaging (MRI) and computed tomography (CT) using clinical imagers. A total of 16 Sprague Dawley rats of about 300 g were used for the pancreas visualization. Following the baseline imaging, a mixed contrast medium dye called GadoIodo-EB containing optimized concentrations of Gd-DOTA, iomeprol and Evens blue was infused into the distally obstructed common bile duct (CBD) for post-contrast imaging with 3.0 T MRI and 128-slice CT scanners. Images were post-processed with the MeVisLab software package. MRI findings were co-registered with CT scans and validated with histomorphology, with relative contrast ratios quantified. Without contrast enhancement, the pancreas was indiscernible. After infusion of GadoIodo-EB solution, only the pancreatic region became outstandingly visible, as shown by 3D rendering MRI and CT and proven by colored dissection and histological examinations. The measured volume of the pancreas averaged 1.12 ± 0.04 cm(3) after standardization. Relative contrast ratios were 93.28 ± 34.61% and 26.45 ± 5.29% for MRI and CT respectively. We have developed a multifunctional contrast medium dye to help clearly visualize and delineate rat pancreas in situ using clinical MRI and CT scanners. The topographic landmarks thus created with 3D demonstration may help to provide guidelines for the next in vivo pancreatic MRI research in rodents.

Pulmonary vascular and right ventricular reserve in patients with normalized resting hemodynamics after pulmonary endarterectomy.

BACKGROUND: Patients with normalized mean pulmonary artery pressure (mPAP) after pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) do not always regain normal exercise capacity. We evaluated right ventricular function, its interaction with both pulsatile and resistive afterload, and the effect of sildenafil during exercise in these patients. METHODS AND RESULTS: Fourteen healthy controls, 15 CTEPH patients, and 7 patients with normalized resting mPAP (≤25 mm Hg) post-PEA underwent cardiopulmonary exercise testing, followed by cardiac magnetic resonance imaging with simultaneous invasive mPAP measurement during incremental supine cycling exercise. Peak oxygen consumption and peak heart rate were significantly reduced in post-PEA and CTEPH patients compared to controls. The mPAP-cardiac output slope was steeper in post-PEA patients than in controls and similar to CTEPH. Relative to controls, resting right ventricular ejection fraction was reduced in CTEPH, but not in post-PEA patients. In contrast, peak exercise right ventricular ejection fraction was reduced both in post-PEA and CTEPH patients. Exercise led to reduction of pulmonary arterial compliance in all groups. Nevertheless, resting pulmonary arterial compliance values in CTEPH and post-PEA patients were even lower than those in controls at peak exercise. In post-PEA patients, sildenafil did not affect resting hemodynamics nor right ventricular function, but decreased the mPAP/cardiac output slope and increased peak exercise right ventricular ejection fraction. CONCLUSIONS: Exercise intolerance in post-PEA patients is explained by abnormal pulmonary vascular reserve and chronotropic incompetence. The mPAP/cardiac output slope and pulmonary arterial compliance are sensitive measures demonstrating abnormal resistive and pulsatile pulmonary vascular function in post-PEA patients. These abnormalities are partially attenuated with sildenafil.