AcquisitionFocus: Joint Optimization of Acquisition Orientation and Cardiac Volume Reconstruction Using Deep Learning.

In cardiac cine imaging, acquiring high-quality data is challenging and time-consuming due to the artifacts generated by the heart's continuous movement. Volumetric, fully isotropic data acquisition with high temporal resolution is, to date, intractable due to MR physics constraints. To assess whole-heart movement under minimal acquisition time, we propose a deep learning model that reconstructs the volumetric shape of multiple cardiac chambers from a limited number of input slices while simultaneously optimizing the slice acquisition orientation for this task. We mimic the current clinical protocols for cardiac imaging and compare the shape reconstruction quality of standard clinical views and optimized views. In our experiments, we show that the jointly trained model achieves accurate high-resolution multi-chamber shape reconstruction with errors of <13 mm HD95 and Dice scores of >80%, indicating its effectiveness in both simulated cardiac cine MRI and clinical cardiac MRI with a wide range of pathological shape variations.

Predicting mortality from AI cardiac volumes mass and coronary calcium on chest computed tomography.

Chest computed tomography is one of the most common diagnostic tests, with 15 million scans performed annually in the United States. Coronary calcium can be visualized on these scans, but other measures of cardiac risk such as atrial and ventricular volumes have classically required administration of contrast. Here we show that a fully automated pipeline, incorporating two artificial intelligence models, automatically quantifies coronary calcium, left atrial volume, left ventricular mass, and other cardiac chamber volumes in 29,687 patients from three cohorts. The model processes chamber volumes and coronary artery calcium with an end-to-end time of ~18 s, while failing to segment only 0.1% of cases. Coronary calcium, left atrial volume, and left ventricular mass index are independently associated with all-cause and cardiovascular mortality and significantly improve risk classification compared to identification of abnormalities by a radiologist. This automated approach can be integrated into clinical workflows to improve identification of abnormalities and risk stratification, allowing physicians to improve clinical decision-making.

Impact of breath hold on regional nodal irradiation and heart volume in field in left breast cancer adjuvant irradiation.

PURPOSE: Compared to the free-breathing technique, adjuvant left breast irradiation after breast-conserving surgery or mastectomy using the breath-hold method significantly reduces the heart mean dose, Left anterior descending artery, and ipsilateral lung doses. Movement with deep inspiration may also reduce heart volume in the field and regional node doses. MATERIALS AND METHODS: Pre-radiotherapy planning CT was performed in the free-breathing, and breath-hold techniques using RPM, demographic information, clinicopathological data, heart volume in the field, heart mean dose, LAD mean dose, and regional nodal doses were calculated in both free breathing and DIBH. Fifty patients with left breast cancer receiving left breast adjuvant radiation were enrolled. RESULTS: There was no significant difference in axillary LN coverage between the two techniques, except for SCL maximum dose, Axilla I node maximum dose, and Axilla II minimum dose in favor of the breath hold technique. The mean age was 47.54 years, 78% had GII IDC, 66% had positive LVSI results, and 74% of patients had T2. The breath hold strategy resulted in considerably decreased mean heart dose (p = 0.000), LAD dose (p = 0.000), ipsilateral lung mean dose (p = 0.012), and heart volume if the field (p = 0.013). The mean cardiac dosage and the dose of the LAD were significantly correlated (p = 0.000, R = 0.673). Heart volume in the field and heart mean dosage was not significantly correlated (p = 0.285, r = - 0.108). CONCLUSION: When compared to free breathing scans, DIBH procedures result in considerably reduced dosage to the OAR and no appreciable changes in dose exposure to regional lymph node stations in patients with left-sided breast cancer.

Indexing cardiac volumes for peak oxygen uptake to improve differentiation of physiological and pathological remodeling: from elite athletes to heart failure patients.

AIMS: Cardiovascular structures adapt to meet metabolic demands, but current methodology for indexing by body size does not accurately reflect such variations. Therefore, we aimed to investigate how left ventricular end-diastolic volume (LVEDV) and left atrial maximal volume (LAVmax) are associated with absolute (L/min) peak oxygen uptake (VO2peak) and fat-free mass (FFM) compared to body surface area (BSA). We subsequently assessed the impact of indexing by absolute VO2peak, FFM, and BSA to discriminate pathological from physiological remodeling. METHODS AND RESULTS: We used data from 1190 healthy adults to explore relationships for BSA, FFM, and absolute VO2peak with LVEDV and LAVmax by regression and correlation analyses. We then compared these indexing methods for classification to normalcy/pathology in 61 heart failure patients and 71 endurance athletes using the chi-squared and Fisher exact tests and the net reclassification and integrated discrimination indices. Absolute VO2peak correlated strongly with LVEDV, explaining 52% of variance vs. 32% for BSA and 44% for FFM. Indexing LVEDV for VO2peak improved discrimination between heart failure patients and athletes on top of indexing to BSA. Seventeen out of 18 athletes classified to pathology by BSA were reclassified to normalcy by VO2peak indexing (P < 0.001), while heart failure patients were reclassified to pathology (39-95%, P < 0.001). All indexing methods explained below 20% of the variance in LAVmax in univariate models. CONCLUSIONS: Indexing LVEDV to VO2peak improves the ability to differentiate physiological and pathological enlargement. The LVEDV to absolute VO2peak ratio may be a key index in diagnosing heart failure and evaluating the athlete's heart.

Perioperative Fluid Management and Volume Assessment.

Fluid therapy is an integral component of perioperative care and helps maintain or restore effective circulating blood volume. The principal goal of fluid management is to optimize cardiac preload, maximize stroke volume, and maintain adequate organ perfusion. Accurate assessment of volume status and volume responsiveness is necessary for appropriate and judicious utilization of fluid therapy. To accomplish this, static and dynamic indicators of fluid responsiveness have been widely studied. This review discusses the overarching goals of perioperative fluid management, reviews the physiology and parameters used to assess fluid responsiveness, and provides evidence-based recommendations on intraoperative fluid management.

Echocardiography Provides a Reliable Estimate of Total Cardiac Volume for Pediatric Heart Transplantation.

BACKGROUND: Donor-to-recipient size matching for heart transplantation typically involves comparing donor and recipient body weight; however, weight is not linearly related to cardiac size. Attention has shifted toward the use of computed tomography- (CT-) derived total cardiac volume (TCV), that is, CT-TCV, to compare donor and recipient heart organ size. At this time, TCV size matching is near impossible for most centers due to logistical limitations. To overcome this impediment, echocardiogram-derived TCV (ECHO-TCV) is an attractive, alternative option to estimate CT-TCV. The goal of this study is to test whether ECHO-TCV is an accurate and reliable surrogate for TCV measurement compared with the gold standard CT-TCV. METHODS: ECHO-TCV and CT-TCV were measured in a cohort spanning the neonatal to young adult age range with the intention to simulate the pediatric heart transplant donor pool. ECHO-TCV was measured using a modified Simpson's summation-of-discs method from the apical 4-chamber (A4C) view. The gold standard of CT-TCV was measured from CT scans using three-dimensional reconstruction software. The relationship between ECHO-TCV and CT-TCV was evaluated and compared with other anthropometric and image-based markers that may predict CT-TCV. Inter-rater reliability of ECHO-TCV was tested among 4 independent observers. Subanalyses were performed to identify imaging views and timing that enable greater accuracy of ECHO-TCV. RESULTS: Banked imaging data of 136 subjects with both echocardiogram and CT were identified. ECHO-TCV demonstrated a linear relationship to CT-TCV with a Pearson correlation coefficient of r = 0.96 (95% CI, 0.95-0.97; P < .0001) and mean absolute percent error of 8.6%. ECHO-TCV correlated most strongly with CT-TCV in the subset of subjects <4 years of age (n = 33; r = 0.98; 95% CI, 0.96-0.99; P < .0001). The single-score intraclass correlation coefficient across all 4 raters is 0.96 (interquartile range, 0.93-0.98). ECHO-TCV measured from a standard A4C view at end diastole with the atria in the plane of view had the strongest correlation to CT-TCV. CONCLUSIONS: ECHO-TCV by the A4C view was found to be both an accurate and reliable alternative measurement of CT-TCV and is derived from readily available donor ECHO images. The ECHO-TCV findings in this study make the ECHO method an attractive means of direct donor-to-recipient TCV size matching in pediatric heart transplantation.

Epicardial Fat Volume, Cardiac Function, and Incident Heart Failure: The Rotterdam Study.

Background Larger epicardial fat volume (EFV) has been associated with increased risks of cardiovascular disease and atrial fibrillation. Yet, evidence on the association of EFV with cardiac function and incident heart failure (HF) remains scarce. Methods and Results We included 2103 participants (mean age, 68 years; 54.4% women) from the prospective population-based RS (Rotterdam Study) with computed tomography-based EFV and repeated echocardiography-based assessment of left ventricular (LV) systolic and diastolic function. Linear mixed effects and Cox-proportional hazard regression models, adjusted for cardiovascular risk factors, were used to assess the associations of EFV with repeated measurements of echocardiographic parameters and with incident HF. During a median follow-up of 9.7 years, 124 HF events occurred (incidence rate, 6.37 per 1000 person-years). For LV systolic function, 1-SD larger EFV was associated with 0.76 (95% CI, 0.54-0.98) mm larger LV end-diastolic dimension, 0.66 (95% CI, 0.47-0.85) mm larger LV end-systolic dimension, and 0.56% (95% CI, -0.86% to -0.27%) lower LV ejection fraction. Interactions between EFV and time were small. For LV diastolic function, 1-SD larger EFV was associated with 1.02 (95% CI, 0.78-1.27) mm larger left atrial diameter. Larger EFV was also associated with incident HF (hazard ratio per 1-SD increase in EFV, 1.34 [95% CI, 1.07-1.68] per 1-SD larger EFV). Conclusions We report an independent association between EFV with new-onset HF in the general population. EFV seems to exert its influence on HF through different pathways contributing to deteriorations in systolic function and larger left atrial size in part, likely through mechanical restraint and hypertrophy.

Surgically Induced Cardiac Volume Overload by Aortic Regurgitation in Mouse.

Aortic regurgitation (AR) is a common valvular heart disease that exerts volume overload on the heart and represents a global public health problem. Although mice are widely applied to shed light on the mechanisms of cardiovascular disease, mouse models of AR, especially those induced by surgery, are still paucity. Here, a mouse model of AR was described in detail which is surgically induced by disruption of the aortic valves under high-resolution echocardiography. In accordance with regurgitated blood flow, AR mouse hearts present a distinctive and clinically relevant volume overload phenotype, which is characterized by eccentric hypertrophy and cardiac dysfunction, as evidenced by echocardiographic and invasive hemodynamic evaluation. Our proposal, in a reliable and reproducible manner, provides a practical guide on the establishment and assessment of a mouse model of AR for future studies on molecular mechanisms and therapeutic targets of volume overload cardiomyopathy.

Comparing donor and recipient total cardiac volume predicts risk of short-term adverse outcomes following heart transplantation.

INTRODUCTION: In pediatric heart transplantation, donor: recipient weight ratio (DRWR) has long been the sole metric for size matching. Total cardiac volume (TCV)-based size matching has emerged as a novel method to precisely identify an upper limit of donor organ size of a heart transplant recipient while minimizing the risk of complications from oversizing. The clinical adoption of donor: recipient volume ratio (DRVR) to prevent short-term adverse outcomes of oversizing is unknown. The purpose of this single-center study is to determine the relationship of DRWR and DRVR to the risk of post-operative complications from allograft oversizing. METHODS: Recipient TCV was measured from imaging studies and donor TCV was calculated from published TCV prediction models. DRVR was defined as donor TCV divided by recipient TCV. The primary outcome was short-term post-transplant complications (SPTC), a composite outcome of delayed chest closure and prolonged intubation > 7 days. A multivariable logistic regression model of DRWR (cubic spline), DRVR (linear) and linear interaction between DRWR and DRVR was used to examine the probability of experiencing a SPTC over follow-up as a function of DRWR and DRVR. RESULTS: A total of 106 transplant patients' records were reviewed. Risk of the SPTC increased as DRVR increased. Both low and high DRWR was associated with the SPTC. A logistic regression model including DRWR and DRVR predicted SPTC with an AUROC curve of 0.74. [95% CI 0.62 0.85]. The predictive model identified a "low-risk zone" of donor-recipient size match between a weight ratio of 0.8 and 2.0 and a TCV ratio less than 1.0. CONCLUSION: DRVR in combination with DRWR predicts short-term post-transplant adverse events. Accepting donors with high DRWR may be safely performed when DRVR is considered.

Evaluación del grado de congestión clínica y hemodinámica como predictores de mortalidad en pacientes ambulatorios con insuficiencia cardíaca de edad avanzada / Assessment of clinical and hemodynamic congestion as predictors of mortality in elderly outpatients with heart failure

Introducción El objetivo del estudio fue evaluar si la exploración física y la determinación de la fracción N-terminal del propéptido natriurético cerebral pueden predecir un peor pronóstico en pacientes ambulatorios con insuficiencia cardíaca. Pacientes y métodos Estudio retrospectivo llevado a cabo entre 2010 y 2018, en 238 pacientes diagnosticados de insuficiencia cardíaca. Al inicio, se evaluó la presencia de crepitantes pulmonares y edema de miembros inferiores (congestión clínica) junto con la fracción N-terminal del propéptido natriurético cerebral≥1500pg/mL (congestión hemodinámica). Los pacientes se clasificaron en 4 grupos en función del patrón congestivo: sin congestión (G1) (n=50); con congestión clínica (G2) (n=43); con congestión hemodinámica (G3) (n=73) y con congestión clínica y hemodinámica (G4) (n=72). El objetivo primario fue la muerte por cualquier causa al año de seguimiento. Resultados Se analizaron un total de 238 pacientes, edad media 82 años, 61,8% mujeres, y 20,7% con fracción de eyección del ventrículo izquierdo reducida. Treinta pacientes (12,6%) fallecieron en el primer año de seguimiento. Después de ajustar por variables de confusión (sexo, alta hospitalaria reciente por insuficiencia cardíaca, filtrado glomerular estimado, y fracción de eyección del ventrículo izquierdo), el riesgo de muerte en cada grupo,al compararlos con el grupo de referencia G1, fue: G2, HR 4,121 (IC95% 1,131–15,019); G3, HR 2,511 (IC95% 1,007-6,263), y; G4, HR 7,418 (IC95% 1,630-33,763). Conclusión La congestión en pacientes ambulatorios con insuficiencia cardíaca se correlaciona con el pronóstico. Los pacientes con congestión clínica y hemodinámica tuvieron el mayor riesgo de muerte global al año (AU)

Introduction This work aims to evaluate whether a clinical examination and measurement of N-terminal pro-brain natriuretic peptide can predict poor prognosis in outpatients with heart failure. Patients and methods We carried out a retrospective study from 2010 to 2018 in 238 patients diagnosed with heart failure. At baseline, we evaluated the presence of pulmonary rales and bilateral leg edema (clinical congestion) together with N-terminal pro-brain natriuretic peptide≥1500 pg/mL (hemodynamic congestion). Patients were classified into 4 groups depending on their congestion pattern: no congestion (G1) (n=50); clinical congestion (G2) (n=43); hemodynamic congestion (G3) (n=73); and clinical and hemodynamic congestion (G4) (n=72). The primary outcome was all-cause mortality at one year of follow-up. Results A total of 238 patients were included. The mean age was 82 years, 61.8% were women, and 20.7% had reduced left ventricular ejection fraction. Thirty patients died in the first year of follow-up (12.6%). After controlling for confounding variables (sex, recent discharge for heart failure, estimated glomerular filtration rate, and left ventricular ejection fraction), the independent risk of death in each group compared to G1 as the reference group was: G2: HR 4.121 (95%CI 1.131-15.019); G3: HR 2.511 (95%CI 1.007-6.263); and G4: HR 7.418 (95%CI 1.630-33.763). Conclusion Congestion in outpatients with heart failure correlates with prognosis. Patients with both clinical and hemodynamic congestion had the highest risk of all-cause death at one year (AU)

Diferencias de género en la titulación de fármacos de pacientes con insuficiencia cardiaca y fracción de eyección reducida del ensayo ETIFIC / Gender differences in drug titration among heart failure patients with reduced ejection fraction in the ETIFIC trial

Introducción y objetivos El tratamiento óptimo disminuye la mortalidad y hospitalizaciones por insuficiencia cardiaca (IC) en pacientes con IC y fracción de eyección reducida. En los ensayos clínicos las mujeres estuvieron infrarrepresentadas y no fueron evaluadas específicamente. Este estudio buscó comparar la seguridad y efectividad de titulación (ajuste de dosis) de fármacos en mujeres y varones. Métodos Estudio post hoc de género del ensayo aleatorizado multicéntrico ETIFIC. Se incluyeron pacientes hospitalizados con IC de novo y fracción de eyección reducida. Proceso estructurado de titulación en unidades de IC. Objetivo principal: la dosis relativa media de bloqueadores beta (% de la dosis objetivo) alcanzada por mujeres frente a varones. Objetivos secundarios: dosis relativas medias de otros fármacos de IC, eventos adversos y resultados clínicos a 6 meses. Resultados Se incluyeron 320 pacientes, 83 (25,93%) mujeres y 237 (74,06%) varones. (76 frente a 213 analizados). Media±desviación estándar de dosis relativa de bloqueadores beta mujeres frente a varones: 62,08±30,72% frente a 64,4±32,77%; diferencia −2,32%; IC95%, −10,58-5,94; p=0,580, antagonistas del receptor de mineralocorticoides 79,85±27,72% comparado con 67,29±31,43%; p=0,003, sin diferencias significativas en dosificación de otros fármacos. El análisis multivariante no encontró diferencias significativas. Mortalidad cardiovascular 1 (1,20%) frente a 3 (1,26%), p=1 y 0 hospitalizaciones por IC (0,00%) frente a 10 (4,22%), p=0,125. Conclusiones En un análisis post hoc del ensayo ETIFIC de titulación en IC no encontramos diferencias de género significativas en dosificación, mortalidad cardiovascular y hospitalizaciones por IC (AU)

Introduction and objectives Optimal medical therapy decreases mortality and heart failure (HF) hospitalizations in HF patients with reduced left ventricular ejection fraction. Women have been underrepresented in clinical trials and not specifically evaluated. This study aimed to compare the safety and effectiveness of drug titration in women vs men. Methods This post hoc gender study of the ETIFIC multicenter randomized trial included hospitalized patients with new-onset HF with reduced ejection fraction and New York Heart Association II-III and no contraindications to beta-blockers. A structured 4-month titration process was implemented in HF clinics. The primary endpoint was the mean relative dose (% of target dose) of beta-blockers achieved by women vs men. Secondary endpoints included the mean relative doses of angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and mineralocorticoid receptor antagonists, adverse events, and other clinical outcomes at 6 months. Results A total of 320 patients were included, 83 (25.93%) women and 237 (74.06%) men (76 vs 213 analyzed). The mean±standard deviation of the relative doses achieved by women vs men were as follows: beta-blockers 62.08%±30.72% vs 64.4%±32.77%, with a difference of−2.32% (95%CI,−10.58-5.94), P = .580; and mineralocorticoid receptor antagonists 79.85%±27.72% vs 67.29%±31.43%, P =.003. No other differences in drug dosage were found. Multivariate analysis showed nonsignificant differences. CV mortality was 1 (1.20%) vs 3 (1.26%), P=1, and HF hospitalizations 0 (0.00%) vs 10 (4.22%), P=.125. Conclusions In a post hoc analysis from the HF-titration ETIFIC trial, we found nonsignificant gender differences in drug dosage, cardiovascular mortality, and HF hospitalizations (AU)

Analysis of different training load monitoring methods in youth women handball players

This study examined the association between different methods for training load (TL) monitoring during youth handball training. Distance covered, heart rate and session rating of perceived exertion [SRPE] were recorded during 12 training sessions in 14 youth women handball athletes (16.9±1.1 years). Internal load models based on SRPE and Edwards’ Trimp were calculated. An oscillatory feature was observed for the three methods of TL assessment (SRPE: 383±159 A.U., Edwards’ Trimp: 252±71 A.U., total distance: 3997±1291 m). A large correlation was found between Edwards’ Trimp and distance covered (r=0.59). A moderate correlation was observed for Edwards’ Trimp vs. SRPE (r=0.36), and between SRPE vs. distance covered (r=0.49). Shared variances of 13–35% were observed between TL methods comparisons. The results suggest that different constructs seem to be measured by each load model. Additionally, SRPE is a simple and low-cost method that might be used for TL monitoring in handball. (AU)

EpCAM y obstrucción microvascular en pacientes con un IAMCEST: estudio con resonancia magnética cardiaca / EpCAM and microvascular obstruction in patients with STEMI: a cardiac magnetic resonance study

Introducción y objetivos: La obstrucción microvascular (OMV) se asocia negativamente con la estructura cardiaca y el pronóstico de los pacientes tras un infarto agudo de miocardio con elevación del segmento ST (IAMCEST). El factor epithelial cell adhesion molecule (EpCAM), implicado en la cohesión de las células epiteliales, está poco estudiado en el contexto de la OMV. Por ello, el objetivo de este estudio es evaluar en una cohorte de pacientes con IAMCEST la asociación entre la concentración de EpCAM circulante con la extensión de la OMV, determinada por resonancia magnética cardiaca (RMC), y la función sistólica en fases crónicas. Métodos: Se incluyó prospectivamente a 106 pacientes con un primer IAMCEST tratados con angioplastia primaria percutánea. La concentración sérica de EpCAM se determinó 24h tras la reperfusión coronaria. Se estudió a todos los pacientes mediante RMC a la semana y a los 6 meses del IAMCEST. Se evaluó la correlación entre los valores de EpCAM circulante con la OMV, los índices de función sistólica y la fracción de eyección del ventrículo izquierdo. Resultados: La media de edad de la cohorte era 59±13 años y el 76% eran varones. Se dicotomizó a los pacientes según la mediana de EpCAM (4,48 pg/ml). Se observó que los pacientes que tenían valores más bajos de EpCAM presentaban una mayor extensión de la OMV (p=0,021) y un mayor tamaño de infarto (p=0,019) en los estudios de RMC realizados 1 semana después del evento cardiovascular. Respecto a las variables de presentación, la concentración de EpCAM se asoció significativamente con la presencia de OMV en análisis de regresión logística binaria univariable (OR=0,58; IC95%, 0,38-0,88; p=0,011) y multivariable (OR=0,55; IC95%, 0,35-0,87; p=0,010). A pesar de que la OMV tiende a resolverse espontáneamente en fases crónicas, unos valores más bajos de EpCAM se correlacionaron con una peor función sistólica (AU)

Introduction and objectives: Microvascular obstruction (MVO) is negatively associated with cardiac structure and worse prognosis after ST-segment elevation myocardial infarction (STEMI). Epithelial cell adhesion molecule (EpCAM), involved in epithelium adhesion, is an understudied area in the MVO setting. We aimed to determine whether EpCAM is associated with the appearance of cardiac magnetic resonance (CMR)-derived MVO and long-term systolic function in reperfused STEMI. Methods: We prospectively included 106 patients with a first STEMI treated with percutaneous coronary intervention, quantifying serum levels of EpCAM 24hours postreperfusion. All patients underwent CMR imaging 1 week and 6 months post-STEMI. The independent correlation of EpCAM with MVO, systolic volume indices, and left ventricular ejection fraction was evaluated. Results: The mean age of the sample was 59±13 years and 76% were male. Patients were dichotomized according to median EpCAM (4.48 pg/mL). At 1-week CMR, lower EpCAM was related to extensive MVO (P=.021) and larger infarct size (P=.019). At presentation, EpCAM values were significantly associated with the presence of MVO in univariate (OR, 0.58; 95%CI, 0.38-0.88; P=.011) and multivariate logistic regression models (OR, 0.55; 95%CI, 0.35-0.87; P=.010). Although MVO tends to resolve at chronic phases, decreased EpCAM was associated with worse systolic function: reduced left ventricular ejection fraction (P=.009) and higher left ventricular end-systolic volume (P=.043). Conclusions: EpCAM is associated with the occurrence of CMR-derived MVO at acute phases and long-term adverse ventricular remodeling post-STEMI

Estimating heart mass from heart volume as measured from post-mortem computed tomography.

Heart mass can be predicted from heart volume as measured from post-mortem computed tomography (PMCT), but with limited accuracy. Although related to heart mass, age, sex, and body dimensions have not been included in previous studies using heart volume to estimate heart mass. This study aimed to determine whether heart mass estimation can be improved when age, sex, and body dimensions are used as well as heart volume. Eighty-seven (24 female) adult post-mortem cases were investigated. Univariable predictors of heart mass were determined by Spearman correlation and simple linear regression. Stepwise linear regression was used to generate heart mass prediction equations. Heart mass estimate performance was tested using median mass comparison, linear regression, and Bland-Altman plots. Median heart mass (P = 0.0008) and heart volume (P = 0.008) were significantly greater in male relative to female cases. Alongside female sex and body surface area (BSA), heart mass was univariably associated with heart volume in all cases (R2 = 0.72) and in male (R2 = 0.70) and female cases (R2 = 0.64) when segregated. In multivariable regression, heart mass was independently associated with age and BSA (R2 adjusted = 0.46-0.54). Addition of heart volume improved multivariable heart mass prediction in the total cohort (R2 adjusted = 0.78), and in male (R2 adjusted = 0.74) and female (R2 adjusted = 0.74) cases. Heart mass estimated from multivariable models incorporating heart volume, age, sex, and BSA was more predictive of actual heart mass (R2 = 0.75-0.79) than models incorporating either age, sex, and BSA only (R2 = 0.48-0.57) or heart volume only (R2 = 0.64-0.73). Heart mass can be more accurately predicted from heart volume measured from PMCT when combined with the classical predictors, age, sex, and BSA.

Initial estimates of continuous positive airway pressure (CPAP) on heart volume, position and motion in patients receiving chest radiation.

To evaluate effects of Continuous Positive Airway Pressure (CPAP) on cardiac position, volume, and motion in a cohort of patients receiving thoracic radiation therapy (RT). Patients underwent 3-dimensional (3D) and 4D-computerized tomography (CT) imaging with free-breathing (FB) and CPAP for RT planning. All scans were co-registered on the treatment planning system for contouring, identification of the center of heart volume and comparative measurements of cardiac displacement, volume and motion. Heart volume (HV) was created from 3D-CT contours. Range of heart motion was estimated by creating an internal heart volume (IHV) from 4D-CT contours. Magnitude of cardiac motion (cardiac excursion) was recorded as the difference in volume between IHV and HV. Wilcoxon signed rank test and Spearmen's rank correlation coefficient were used to assess differences between variables and correlations between lung volume and heart parameters. Results from 9 patient data sets were available for this report. Compared to FB, CPAP use was associated with caudal displacement of the HV (1 cm, p < 0.008) and IHV (1.1 cm, p < 0.008). CPAP use decreased HV 6% (p < 0.008) and IHV 13% (p < 0.008). Cardiac excursion was 49% (p < 0.01) less with CPAP than with FB. CPAP use increased mean lung volume by 30% (p < 0.008) which correlated with caudal displacement of the HV (r = 0.83, p < 0.008) and IHV (r = 0.98, p < 0.001). The use of CPAP reduced cardiac motion and volume although the reduction in volume was minimal. The increase in lung volume correlated with caudal displacement of the heart. These results suggest the mechanism for achieving dosimetric benefit was obtained by cardiac displacement and decreased lung and heart motion rather than reduction of HV. Further evaluation of CPAP as a novel technique to reduce heart exposure when offering RT is warranted.