Three-dimensional magnetic resonance cholangiography is superior to two-dimensional single-shot magnetic resonance cholangiography for visualization and image quality of the feline and canine biliary tract: A postmortem study.

Magnetic resonance cholangiography (MRC) is an established diagnostic tool for noninvasive assessment of the biliary tract in humans. It has also been found to be feasible in companion animals, but no published studies have compared MRC sequences in veterinary medicine. The present study is part of a prospective, observational, analytical investigation on MR cholangiopancreatography performed on the donated bodies of 12 cats and eight dogs. The main aim of this study was to compare the images of 2D-SSh-TSE-MRC and 3D-TSE-MRC sequences for visualization and image quality of the feline and canine biliary tract. Both sequences are T2-weighted and noncontrast. Three independent readers scored the visibility of four segments of the biliary tract, namely the gallbladder (GB), cystic duct, common bile duct (CBD), and extrahepatic ducts, and the image quality of the two MRC sequences using five-point Likert scales. Wilcoxon signed-rank test was used to compare the scores between the MRC sequences separately for cats and dogs. Inter- and intraobserver agreements were measured using Gwet's AC2 with linear weighting. The 3D-TSE-MRC images were scored significantly higher than the 2D-SSh-TSE-MRC for both visibility and image quality (P < .001-.016 for cats, P = .008-.031 for dogs); the only exception was GB in dogs. In both cats and dogs, interobserver agreement for segment visibility and image quality ranged from slight to substantial in 2D-SSh-TSE-MRC and from poor to almost perfect in 3D-TSE-MRC. Most of the assessments (73% for segment visibility and 66% for image quality) had substantial to almost perfect intraobserver agreement. Findings from the current study support the use of 3D-TSE-MRC over 2D-SSh-TSE-MRC for evaluation of the feline and canine biliary tract, but further studies on live animals are warranted.

Follow-up of intramyocardial bone marrow mononuclear cell transplantation beyond 10 years.

Bone marrow mononuclear cells (BMMCs) have been evaluated for their ability to improve cardiac repair and benefit patients with severe ischemic heart disease and heart failure. In our single-center trial in 2006-2011 we demonstrated the safety and efficacy of BMMCs injected intramyocardially in conjunction with coronary artery bypass surgery. The effect persisted in the follow-up study 5 years later. In this study, we investigated the efficacy of BMMC therapy beyond 10 years. A total of 18 patients (46%) died during over 10-years follow-up and 21 were contacted for participation. Late gadolinium enhancement cardiac magnetic resonance imaging (CMRI) and clinical evaluation were performed on 14 patients, seven from each group. CMRIs from the study baseline, 1-year and 5-years follow-ups were re-analyzed to enable comparison. The CMRI demonstrated a 2.1-fold larger reduction in the mass of late gadolinium enhancement values between the preoperative and the over 10-years follow-up, suggesting less scar or fibrosis after BMMC treatment (- 15.1%; 95% CI - 23 to - 6.7% vs. - 7.3%; 95% CI - 16 to 4.5%, p = 0.039), compared to placebo. No differences in mortality or morbidity were observed. Intramyocardially injected BMMCs may exert long-term benefits in patients with ischemic heart failure. This deserves further evaluation in patients who have received BMMCs in international clinical studies over two decades.

Myocardial T1 mapping by cardiac magnetic resonance imaging shows early myocardial changes in treatment-naive patients with active rheumatoid arthritis and positive autoantibodies.

OBJECTIVES: We aimed to study whether myocardial changes are already detectable by cardiac magnetic resonance (CMR) imaging at the time of rheumatoid arthritis (RA) diagnosis. METHODS: This single-centre prospective study included 39 treatment-naive patients with early rheumatoid arthritis (ERA, symptom duration <1 year) without any history of heart disease, and 38 age- and sex-matched healthy volunteers. The disease severity was assessed with clinical evaluation (Disease Activity Score-28 for Rheumatoid Arthritis with CRP (DAS28-CRP) score) and serological testing (rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA)). The ERA patients were classified into group A (DAS28-CRP score ≥3.2, positive RF and ACPA; n=17) and group B (not fulfilling the group A criteria). The ERA patients and healthy controls underwent 1.5T CMR. RESULTS: Group A patients had significantly higher myocardial global T1 relaxation times than the healthy controls, 987 [965, 1003] ms vs. 979 [960, 991] ms (median [IQR]; p=0.041). A significant difference in T1 was found in the basal, mid inferior and mid anterolateral segments. In a multivariate analysis, prolonged global T1 relaxation time was independently associated with female sex (95% CI [5.62, 51.31] ms, p=0.016), and group A status (95% CI [4.65, 39.01] ms p=0.014). CONCLUSIONS: At the time of diagnosis, ERA patients with a higher disease activity (DAS28-CRP score ≥3.2) and both positive RF and ACPA showed prolonged T1 relaxation times in basal myocardial segments. These segments could be most susceptible to the development of myocardial fibrosis, and a segmental reporting style could be useful when estimating the first signs of myocardial fibrosis.

Automatic chest computed tomography image noise quantification using deep learning.

PURPOSE: This study aimed to develop a deep learning (DL) method for noise quantification for clinical chest computed tomography (CT) images without the need for repeated scanning or homogeneous tissue regions. METHODS: A comprehensive phantom CT dataset (three dose levels, six reconstruction methods, amounting to 9240 slices) was acquired and used to train a convolutional neural network (CNN) to output an estimate of local image noise standard deviations (SD) from a single CT scan input. The CNN model consisting of seven convolutional layers was trained on the phantom image dataset representing a range of scan parameters and was tested with phantom images acquired in a variety of different scan conditions, as well as publicly available chest CT images to produce clinical noise SD maps. RESULTS: Noise SD maps predicted by the CNN agreed well with the ground truth both visually and numerically in the phantom dataset (errors of < 5 HU for most scan parameter combinations). In addition, the noise SD estimates obtained from clinical chest CT images were similar to running-average based reference estimates in areas without prominent tissue interfaces. CONCLUSIONS: Predicting local noise magnitudes without the need for repeated scans is feasible using DL. Our implementation trained with phantom data was successfully applied to open-source clinical data with heterogeneous tissue borders and textures. We suggest that automatic DL noise mapping from clinical patient images could be used as a tool for objective CT image quality estimation and protocol optimization.

Characterization of Immune Cell Populations of Cutaneous Neurofibromas in Neurofibromatosis 1.

Cutaneous neurofibromas (cNFs) are characteristic of neurofibromatosis 1 (NF1), yet their immune microenvironment is incompletely known. A total of 61 cNFs from 10 patients with NF1 were immunolabeled for different types of T cells and macrophages, and the cell densities were correlated with clinical characteristics. Eight cNFs and their overlying skin were analyzed for T cell receptor CDR domain sequences, and mass spectrometry of 15 cNFs and the overlying skin was performed to study immune-related processes. Intratumoral T cells were detected in all cNFs. Tumors from individuals younger than the median age of the study participants (33 years), growing tumors, and tumors smaller than the data set median showed increased T cell density. Most samples displayed intratumoral or peritumoral aggregations of CD3-positive cells. T cell receptor sequencing demonstrated that the skin and cNFs host distinct T cell populations, whereas no dominant cNF-specific T cell clones were detected. Unique T cell clones were fewer in cNFs than in skin, and mass spectrometry suggested lower expression of proteins related to T cell-mediated immunity in cNFs than in skin. CD163-positive cells, suggestive of M2 macrophages, were abundant in cNFs. Human cNFs have substantial T cell and macrophage populations that may be tumor-specific.

The contribution of morbidity and unemployment for the reduced labor market participation of individuals with neurofibromatosis 1 in Finland.

Neurofibromatosis 1 (NF1) is a multisystem disorder associated with, for example, a high risk for cancer, a variety of behavioral and cognitive deficits, low educational attainment and decreased income. We now examined the labor market participation of individuals with NF1. We analyzed the numbers of days of work, unemployment, and sickness allowance among 742 Finnish individuals with NF1 aged 20-59 years using nationwide register data from Statistics Finland and the Social Insurance Institution of Finland. The individuals with NF1 were compared with a control cohort of 8716 individuals matched with age, sex, and the area of residence. Individuals with NF1 had a significantly lower number of working days per year than the controls (rate ratio [RR] 0.93, 95% CI 0.91-0.95). Unemployment (RR 1.79, 95% CI 1.58-2.02), and sickness absence (RR 1.44, 95% CI 1.25-1.67) were more frequent in the NF1 than in the control group. The causes of sickness allowances were highly concordant with the previously reported morbidity profile of NF1 including neoplasms, cardiovascular disease, mental and behavioral diseases, and neurological diseases. In conclusion, NF1 significantly interferes with labor market participation via both unemployment and morbidity. Unemployment seems to cause more days of not working than sickness absence.

Hypertension in NF1: A closer look at the primacy of essential hypertension versus secondary causes.

BACKGROUND: We aimed to analyze hypertension in neurofibromatosis type 1 (NF1) in a Finnish population-based cohort in 1996-2014. METHODS: A cohort of 1365 individuals with confirmed NF1 was compared with a control cohort of 13,923 individuals matched for age, sex, and area of residence. Diagnoses of hypertension were retrieved from the Finnish Care Register for Health Care. These registered data were separately analyzed for secondary and essential hypertension. Purchases of antihypertensive drugs were queried from the Finnish Register of Reimbursed Drug Purchases. RESULTS: We identified 115 NF1 patients with hospital diagnosis of hypertension. Our findings revealed a hazard ratio (HR) of 1.64 (95% CI 1.34-2.00, p < 0.001) in NF1 versus controls. NF1 patients presented with a significantly increased hazard for both secondary hypertension (n = 9, HR 3.76, 95% CI 1.77-7.95, p < 0.001) and essential hypertension (n = 98, HR 1.73, 95% CI 1.39-2.14, p < 0.001). No difference in the HR of hypertension was observed between men and women, while NF1 patients with essential hypertension were, on average, younger than the controls. The proportions of individuals with antihypertensive medication did not differ between NF1 patients and controls (OR 0.85). CONCLUSION: NF1 is a risk factor for hypertension. Despite the recognized risk for secondary hypertension, essential hypertension is the predominant type in NF1.

Quality assurance framework for rapid automatic analysis deployment in medical imaging.

PURPOSE: Automatic image analysis algorithms have an increasing role in clinical quality assurance (QA) in medical imaging. Although the implementation of QA calculation algorithms may be straightforward at the development level, actual deployment of a new method to clinical routine may require substantial additional effort from supporting services. We sought to develop a multimodal system that enables rapid implementation of new QA analysis methods in clinical practice. METHODS: The QA system was built using freely available open-source software libraries. The included features were results database, database interface, interactive user interface, e-mail error dispatcher, data processing backend, and DICOM server. An in-house database interface was built, providing the developers of analyses with simple access to the results database. An open-source DICOM server was used for image traffic and automatic initiation of modality-specific QA image analyses. RESULTS: The QA framework enabled rapid adaptation of new analysis methods to automatic image processing workflows. The system provided online data review via an easily accessible user interface. In case of deviations, the system supported simultaneous review of the results for the user and QA expert to trigger corrective actions. In particular, embedded error thresholds, trend analyses, and error-feedback channels were provided to facilitate continuous monitoring and to enable pre-emptive corrective actions. CONCLUSION: An effective and novel QA framework incorporating easy adaptation and scalability to automated image analysis methods was developed. The framework provides an efficient and responsive web-based tool to manage the normal operation, trends, errors, and abnormalities in medical image quality.

Feasibility of Magnetic Resonance Cholangiopancreatography in Dogs-A Post-Mortem Study.

Magnetic resonance cholangiopancreatography (MRCP) is commonly used in humans and is also feasible in cats. The aim of this post-mortem study was to investigate the feasibility of MRCP in eight adult dogs by comparing the visibility and measured diameters of the biliary tract and pancreatic ducts in MRCP with those of fluoroscopic retrograde cholangiopancreatography (FRCP) and corrosion casting. In autopsy, six dogs had no evidence of hepatobiliary disorders, one had pancreatic pathology, and one had biliary pathology. The gallbladder (GB), cystic duct, and common bile duct (CBD) were visible in the MRCP images of all eight dogs. However, the extrahepatic ducts and pancreatic ducts were only variably visible. There was statistical agreement between MRCP and FRCP in measuring the diameters of the GB (fundus and body) and CBD (at papilla and extrahepatic ducts' junction). The diameter measurements correlated between MRCP and corrosion casting. Our study showed that MRCP is feasible in dogs and allowed for proper visualization of the biliary tract. However, ducts with diameters of <1 mm were difficult to visualize using a 1.5 Tesla MRI machine. Further studies are warranted to apply MRCP in the diagnostic imaging of live dogs.

Cardiac output and arteriovenous oxygen difference contribute to lower peak oxygen uptake in patients with fibromyalgia.

BACKGROUND: Patients with fibromyalgia (FM) exhibit low peak oxygen uptake ([Formula: see text]O2peak). We aimed to detect the contribution of cardiac output to ([Formula: see text]) and arteriovenous oxygen difference [Formula: see text] to [Formula: see text] from rest to peak exercise in patients with FM. METHODS: Thirty-five women with FM, aged 23 to 65 years, and 23 healthy controls performed a step incremental cycle ergometer test until volitional fatigue. Alveolar gas exchange and pulmonary ventilation were measured breath-by-breath and adjusted for fat-free body mass (FFM) where appropriate. [Formula: see text] (impedance cardiography) was monitored. [Formula: see text] was calculated using Fick's equation. Linear regression slopes for oxygen cost (∆[Formula: see text]O2/∆work rate) and [Formula: see text] to [Formula: see text]O2 (∆[Formula: see text]/∆[Formula: see text]O2) were calculated. Normally distributed data were reported as mean ± SD and non-normal data as median [interquartile range]. RESULTS: [Formula: see text]O2peak was lower in FM patients than in controls (22.2 ± 5.1 vs. 31.1 ± 7.9 mL∙min-1∙kg-1, P < 0.001; 35.7 ± 7.1 vs. 44.0 ± 8.6 mL∙min-1∙kg FFM-1, P < 0.001). [Formula: see text] and C(a-v)O2 were similar between groups at submaximal work rates, but peak [Formula: see text] (14.17 [13.34-16.03] vs. 16.06 [15.24-16.99] L∙min-1, P = 0.005) and C(a-v)O2 (11.6 ± 2.7 vs. 13.3 ± 3.1 mL O2∙100 mL blood-1, P = 0.031) were lower in the FM group. No significant group differences emerged in ∆[Formula: see text]O2/∆work rate (11.1 vs. 10.8 mL∙min-1∙W-1, P = 0.248) or ∆[Formula: see text]/∆[Formula: see text]O2 (6.58 vs. 5.75, P = 0.122) slopes. CONCLUSIONS: Both [Formula: see text] and C(a-v)O2 contribute to lower [Formula: see text]O2peak in FM. The exercise responses were normal and not suggestive of a muscle metabolism pathology. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03300635. Registered 3 October 2017-Retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT03300635 .

Cholangiopancreatography in cats: a post-mortem comparison of MRI with fluoroscopy, corrosion casting and histopathology.

In human medicine, magnetic resonance cholangiopancreatography (MRCP) is a valuable diagnostic tool for hepatobiliary and pancreatic diseases. In veterinary medicine, however, data evaluating the diagnostic value of MRCP are limited. The primary objectives of this prospective, observational, analytical investigation were to assess whether MRCP reliably visualizes the biliary tract and pancreatic ducts in cats without and with related disorders, and whether MRCP images and measurements of the ducts agree with those of fluoroscopic retrograde cholangiopancreatography (FRCP), corrosion casting and histopathology. A secondary objective was to provide MRCP reference diameters for bile ducts, GB, and pancreatic ducts. Donated bodies of 12 euthanized adult cats underwent MRCP, FRCP, and autopsy with corrosion casting of the biliary tract and pancreatic ducts using vinyl polysiloxane. Diameters of the biliary ducts, gallbladder (GB), and pancreatic ducts were measured using MRCP, FRCP, corrosion casts and histopathologic slides. There was an agreement between MRCP and FRCP in measuring diameters of the GB body, GB neck, cystic duct, and common bile duct (CBD) at papilla. Strong positive correlations existed between MRCP and corrosion casting for measuring GB body and neck, cystic duct, and CBD at the extrahepatic ducts' junction. In contrast to the reference methods, post-mortem MRCP did not visualize right and left extrahepatic ducts, and pancreatic ducts in most cats. Based on this study, MRCP with 1.5 Tesla can be regarded as a contributory method to improve the assessment of feline biliary tract and pancreatic ducts when their diameter is >1 mm.

Hemoglobin mass and performance responses during 4 weeks of normobaric "live high-train low and high".

PURPOSE: To investigate whether 4 weeks of normobaric "live high-train low and high" (LHTLH) causes different hematological, cardiorespiratory, and sea-level performance changes compared to living and training in normoxia during a preparation season. METHODS: Nineteen (13 women, 6 men) cross-country skiers competing at the national or international level completed a 28-day period (∼18 h day-1 ) of LHTLH in normobaric hypoxia of ∼2400 m (LHTLH group) including two 1 h low-intensity training sessions per week in normobaric hypoxia of 2500 m while continuing their normal training program in normoxia. Hemoglobin mass (Hbmass ) was assessed using a carbon monoxide rebreathing method. Time to exhaustion (TTE) and maximal oxygen uptake (VO2max ) were measured using an incremental treadmill test. Measurements were completed at baseline and within 3 days after LHTLH. The control group skiers (CON) (seven women, eight men) performed the same tests while living and training in normoxia with ∼4 weeks between the tests. RESULTS: Hbmass in LHTLH increased 4.2 ± 1.7% from 772 ± 213 g (11.7 ± 1.4 g kg-1 ) to 805 ± 226 g (12.5 ± 1.6 g kg-1 ) (p < 0.001) while it was unchanged in CON (p = 0.21). TTE improved during the study regardless of the group (3.3 ± 3.4% in LHTLH; 4.3 ± 4.8% in CON, p < 0.001). VO2max did not increase in LHTLH (61.2 ± 8.7 mL kg-1 min-1 vs. 62.1 ± 7.6 mL kg-1 min-1 , p = 0.36) while a significant increase was detected in CON (61.3 ± 8.0-64.0 ± 8.1 mL kg-1 min-1 , p < 0.001). CONCLUSIONS: Four-week normobaric LHTLH was beneficial for increasing Hbmass but did not support the short-term development of maximal endurance performance and VO2max when compared to the athletes who lived and trained in normoxia.

Identifying Personality Characteristics and Indicators of Psychological Well-Being Associated With Attrition in the Motivation Makes the Move! Physical Activity Intervention: Randomized Technology-Supported Trial.

BACKGROUND: Data attrition has been a common problem in longitudinal lifestyle interventions. The contributors to attrition in technology-supported physical activity interventions have not been thoroughly studied. OBJECTIVE: The present study examined the roles of personality characteristics and indicators of psychological well-being in data attrition within a technology-supported, longitudinal intervention study with overweight adults. METHODS: Participants (N=89) were adults from the Motivation Makes the Move! intervention study. Data attrition was studied after a 3-month follow-up. Participants' personality characteristics were studied using the Short Five self-report questionnaire. Psychological well-being indicators were assessed with the RAND 36-item health survey, Positive and Negative Affect Schedule, and Beck Depression Inventory. Logistic regression analyses were conducted to assess the risk of discontinuing the study. The analyses were adjusted for sex, age, study group, and educational status. RESULTS: At the 3-month follow-up, 65 of 89 participants (73% of the initial sample) had continued in the study. Participants' personality characteristics and indicators of psychological well-being were not associated with the risk of dropping out of the study (all P values >.05). The results remained the same after covariate controls. CONCLUSIONS: Participant attrition was not attributable to personality characteristics or psychological well-being in the Motivation Makes the Move! study conducted with overweight adults. As attrition remains a challenge within longitudinal, technology-supported lifestyle interventions, attention should be paid to the potentially dynamic natures of personality and psychological well-being, as well as other elements beyond these. TRIAL REGISTRATION: ClinicalTrials.gov NCT02686502; https://clinicaltrials.gov/ct2/show/NCT02686502.

Heart Rate Variability and its Association with Second Ventilatory Threshold Estimation in Maximal Exercise Test.

During incremental exercise, two ventilatory thresholds (VT1, VT2) can normally be identified from gas exchange and ventilatory measurements, such as oxygen uptake, carbon dioxide production and ventilation. In this paper, we attempt to estimate the VT2 using HRV indices derived from a wearable electrocardiogram during a maximal exercise test. The exercise test is conducted on a treadmill that raises its speed by 0.5 km/h every minute. We have 42 measured exercise tests from 24 healthy male volunteers. Three experts determined the VT2 in each exercise test independently and we used principal component subspace reconstruction of their determinations to compute a collective VT2 for our machine learning model. The results demonstrate that the VT2 can be estimated from HRV using the proposed method with a reasonable performance during a maximal exercise test. In 28 out of 42 exercise tests, the HRV-derived threshold (HRVT) is within a minute (one phase) of the collective expert's determination.

Institutional transition from invasive to non-invasive imaging in children with univentricular heart defects: safety and cost savings.

OBJECTIVES: Patients with univentricular heart defects require lifelong imaging surveillance. Recent advances in non-invasive imaging have enabled replacing these patients' routine catheterisation. Our objective was to describe the safety and cost savings of transition of a tertiary care children's hospital from routine invasive to routine non-invasive imaging of low-risk patients with univentricular heart defects. METHODS: This single-centre cohort study consists of 1) a retrospective analysis of the transition from cardiac catheterisation (n = 21) to CT angiography (n = 20) before bidirectional Glenn operation and 2) a prospective study (n = 89) describing cardiac magnetic resonance before and after the total cavopulmonary connection in low-risk patients with univentricular heart defects. RESULTS: Pre-Glenn: The total length of CT angiography was markedly shorter compared to the catheterisation: 30 min (range: 20-60) and 125 min (range: 70-220), respectively (p < 0.001). Catheterisation used more iodine contrast agents than CT angiography, 19 ± 3.9 ml, and 10 ± 2.4 ml, respectively (p < 0.001). Controlled ventilation was used for all catheterised and 3 (15%) CT angiography patients (p < 0.001). No complications occurred during CT angiography, while they emerged in 19% (4/21) catheterisation cases (p < 0.001). CT angiography and catheterisation showed no significant difference in the radiation exposure. Pre-/post-total cavopulmonary connection: All cardiac magnetic resonance studies were successful, and no complications occurred. In 60% of the cardiac magnetic resonance (53/89), no sedation was performed, and peripheral venous pressure was measured in all cases. Cost analysis suggests that moving to non-invasive imaging yielded cost savings of at least €2500-4000 per patient. CONCLUSION: Transition from routine invasive to routine non-invasive pre-and post-operative imaging is safely achievable with cost savings.

Automatic head computed tomography image noise quantification with deep learning.

PURPOSE: Computed tomography (CT) image noise is usually determined by standard deviation (SD) of pixel values from uniform image regions. This study investigates how deep learning (DL) could be applied in head CT image noise estimation. METHODS: Two approaches were investigated for noise image estimation of a single acquisition image: direct noise image estimation using supervised DnCNN convolutional neural network (CNN) architecture, and subtraction of a denoised image estimated with denoising UNet-CNN experimented with supervised and unsupervised noise2noise training approaches. Noise was assessed with local SD maps using 3D- and 2D-CNN architectures. Anthropomorphic phantom CT image dataset (N = 9 scans, 3 repetitions) was used for DL-model comparisons. Mean square error (MSE) and mean absolute percentage errors (MAPE) of SD values were determined using the SD values of subtraction images as ground truth. Open-source clinical head CT low-dose dataset (Ntrain = 37, Ntest = 10 subjects) were used to demonstrate DL applicability in noise estimation from manually labeled uniform regions and in automated noise and contrast assessment. RESULTS: The direct SD estimation using 3D-CNN was the most accurate assessment method when comparing in phantom dataset (MAPE = 15.5%, MSE = 6.3HU). Unsupervised noise2noise approach provided only slightly inferior results (MAPE = 20.2%, MSE = 13.7HU). 2DCNN and unsupervised UNet models provided the smallest MSE on clinical labeled uniform regions. CONCLUSIONS: DL-based clinical image assessment is feasible and provides acceptable accuracy as compared to true image noise. Noise2noise approach may be feasible in clinical use where no ground truth data is available. Noise estimation combined with tissue segmentation may enable more comprehensive image quality characterization.

Hierarchical framework to improve individualised exercise prescription in adults: a critical review.

Physical activity (PA) guidelines for the general population are designed to mitigate the rise of chronic and debilitating diseases brought by inactivity and sedentariness. Although essential, they are insufficient as rates of cardiovascular, pulmonary, renal, metabolic and other devastating and life-long diseases remain on the rise. This systemic failure supports the need for an improved exercise prescription approach that targets the individual. Significant interindividual variability of cardiorespiratory fitness (CRF) responses to exercise are partly explained by biological and methodological factors, and the modulation of exercise volume and intensity seem to be key in improving prescription guidelines. The use of physiological thresholds, such as lactate, ventilation, as well as critical power, have demonstrated excellent results to improve CRF in those struggling to respond to the current homogenous prescription of exercise. However, assessing physiological thresholds requires laboratory resources and expertise and is incompatible for a general population approach. A case must be made that balances the effectiveness of an exercise programme to improve CRF and accessibility of resources. A population-wide approach of exercise prescription guidelines should include free and accessible self-assessed threshold tools, such as rate of perceived exertion, where the homeostatic perturbation induced by exercise reflects physiological thresholds. The present critical review outlines factors for individuals exercise prescription and proposes a new theoretical hierarchal framework to help shape PA guidelines based on accessibility and effectiveness as part of a personalised exercise prescription that targets the individual.

Characterizing geometric distortions of 3D sequences in clinical head MRI.

OBJECTIVE: Phantoms are often used to estimate the geometric accuracy in magnetic resonance imaging (MRI). However, the distortions may differ between anatomical and phantom images. This study aimed to investigate the applicability of a phantom-based and a test-subject-based method in evaluating geometric distortion present in clinical head-imaging sequences. MATERIALS AND METHODS: We imaged a 3D-printed phantom and test subjects with two MRI scanners using two clinical head-imaging 3D sequences with varying patient-table positions and receiver bandwidths. The geometric distortions were evaluated through nonrigid registrations: the displaced acquisitions were compared against the ideal isocenter positioning, and the varied bandwidth volumes against the volume with the highest bandwidth. The phantom acquisitions were also registered to a computed tomography scan. RESULTS: Geometric distortion magnitudes increased with larger table displacements and were in good agreement between the phantom and test-subject acquisitions. The effect of increased distortions with decreasing receiver bandwidth was more prominent for test-subject acquisitions. CONCLUSION: Presented results emphasize the sensitivity of the geometric accuracy to positioning and imaging parameters. Phantom limitations may become an issue with some sequence types, encouraging the use of anatomical images for evaluating the geometric accuracy.

Altered Expiratory Flow Dynamics at Peak Exercise in Adult Men With Well-Controlled Type 1 Diabetes.

Type 1 diabetes may, in time, cause lung dysfunction including airflow limitation. We hypothesized that ventilatory flow morphology during a cardiopulmonary exercise test (CPET) would be altered in adult men with well-controlled type 1 diabetes. Thirteen men with type 1 diabetes [glycated hemoglobin A1c 59 (9) mmol/mol or 7.5 (0.8)%, duration of diabetes 12 (9) years, and age 33.9 (6.6) years] without diagnosed diabetes-related complications and 13 healthy male controls [age 37.2 (8.6) years] underwent CPET on a cycle ergometer (40 W increments every 3 min until volitional fatigue). We used a principal component analysis based method to quantify ventilatory flow dynamics throughout the CPET protocol. Last minute of each increment, peak exercise, and recovery were examined using linear mixed models, which accounted for relative peak oxygen uptake and minute ventilation. The type 1 diabetes participants had lower expiratory peak flow (P = 0.008) and attenuated slope from expiration onset to expiratory peak flow (P = 0.012) at peak exercise when compared with the healthy controls. Instead, during submaximal exercise and recovery, the type 1 diabetes participants possessed similar ventilatory flow dynamics to that of the healthy controls. In conclusion, men with relatively well-controlled type 1 diabetes and without clinical evidence of diabetes-related complications exhibited attenuated expiratory flow at peak exercise independently of peak oxygen uptake and minute ventilation. This study demonstrates that acute exercise reveals alterations in ventilatory function in men with type 1 diabetes but not until peak exercise.

Magnetic resonance imaging safety in patients with abandoned or functioning epicardial pacing leads.

OBJECTIVES: The European Society of Cardiology Guidelines on cardiac pacing from 2021 allow magnetic resonance imaging (MRI) in patients with cardiac implantable electronic devices (CIEDs) but do not recommend MRI in patients with epicardial pacing leads. The clinical dilemma remains whether performing an MRI in patients with CIED and epicardial leads is safe. We aimed to evaluate the safety of performing an MRI in patients with CIED and abandoned or functioning epicardial pacing leads. METHODS: We included all adult patients who underwent clinically indicated MRIs with CIED and functioning or abandoned epicardial leads in a single tertiary hospital between November 2011 and October 2019. The data were retrospectively collected. RESULTS: Twenty-six MRIs were performed on 17 patients with functioning or abandoned epicardial pacing leads. Sixty-nine percent of the MRI scans (18/26) were conducted on patients with functioning epicardial pacing leads. A definite adverse event occurred in one MRI scan. This was a transient elevation of the pacing threshold in a patient with a functioning epicardial ventricular pacing lead implanted 29 years previously. An irreversible atrial pacing lead impedance elevation was detected 6 months after the MRI in another patient; the association with the previous MRI remained unclear. No adverse events were detected in MRIs performed on patients with modern (implanted in 2000 or later) functioning epicardial leads. CONCLUSIONS: MRIs in patients with CIED and modern functioning epicardial pacing leads were performed without detectable adverse events. Further large-scale studies are necessary to confirm MRI safety in patients with epicardial pacing leads. KEY POINTS: • Currently, MRI in patients with cardiac implantable electronic devices (CIEDs) and functioning or abandoned epicardial pacing leads is not recommended. • MRIs in patients with CIED and modern functioning epicardial leads (implanted in 2000 or later) were performed without detectable adverse events in our patient cohort. • Allowing MRI in patients with epicardial pacing leads may significantly improve the diagnostic work-up, especially in specific patient groups, such as patients with congenital heart disease.