End-systole and end-diastole detection in short axis cine MRI using a fully convolutional neural network with dilated convolutions

[EN] The correct assessment and characterization of heart anatomy and functionality is usually done through inspection of magnetic resonance image cine sequences. In the clinical setting it is especially important to determine the state of the left ventricle. This requires the measurement of its volume in the end-diastolic and end-systolic frames within the sequence trough segmentation methods. However, the first step required for this analysis before any segmentation is the detection of the end-systolic and end-diastolic frames within the image acquisition. In this work we present a fully convolutional neural network that makes use of dilated convolutions to encode and process the temporal information of the sequences in contrast to the more widespread use of recurrent networks that are usually employed for problems involving temporal information. We trained the network in two different settings employing different loss functions to train the network: the classical weighted cross-entropy, and the weighted Dice loss. We had access to a database comprising a total of 397 cases. Out of this dataset we used 98 cases as test set to validate our network performance. The final classification on the test set yielded a mean frame distance of 0 for the end-diastolic frame (i.e.: the selected frame was the correct one in all images of the test set) and 1.242 (relative frame distance of 0.036) for the end-systolic frame employing the optimum setting, which involved training the neural network with the Dice loss. Our neural network is capable of classifying each frame and enables the detection of the end-systolic and end-diastolic frames in short axis cine MRI sequences with high accuracy.Funding sources This work was partially supported by the Conselleria d'Innovació, Universitats, Ciència i Societat Digital, Generalitat Valenciana (grants AEST/2020/029 and AEST/2021/050) .Pérez-Pelegrí, M.; Monmeneu, JV.; López-Lereu, MP.; Maceira, AM.; Bodi, V.; Moratal, D. (2022). End-systole and end-diastole detection in short axis cine MRI using a fully convolutional neural network with dilated convolutions. Computerized Medical Imaging and Graphics. 99:1-8. https://doi.org/10.1016/j.compmedimag.2022.102085189

Automatic left ventricle volume calculation with explainability through a deep learning weak-supervision methodology

[EN] Background and objective: Magnetic resonance imaging is the most reliable imaging technique to assess the heart. More specifically there is great importance in the analysis of the left ventricle, as the main pathologies directly affect this region. In order to characterize the left ventricle, it is necessary to extract its volume. In this work we present a neural network architecture that is capable of directly estimating the left ventricle volume in short axis cine Magnetic Resonance Imaging in the end-diastolic frame and provide a segmentation of the region which is the basis of the volume calculation, thus offering explain-ability to the estimated value. Methods: The network was designed to directly target the volumes to estimate, not requiring any labeled segmentation on the images. The network was based on a 3D U-net with extra layers defined in a scan-ning module that learned features like the circularity of the objects and the volumes to estimate in a weakly-supervised manner. The only targets defined were the left ventricle volumes and the circularity of the object detected through the estimation of the pi value derived from its shape. We had access to 397 cases corresponding to 397 different subjects. We randomly selected 98 cases to use as test set. Results: The results show a good match between the real and estimated volumes in the test set, with a mean relative error of 8% and a mean absolute error of 9.12 ml with a Pearson correlation coefficient of 0.95. The derived segmentations obtained by the network achieved Dice coefficients with a mean value of 0.79. Conclusions: The proposed method is capable of obtaining the left ventricle volume biomarker in the end-diastole and offer an explanation of how it obtains the result in the form of a segmentation mask without the need of segmentation labels to train the algorithm, making it a potentially more trustworthy method for clinicians and a way to train neural networks more easily when segmentation labels are not readily available.The authors acknowledge financial support from the Consel-leria d'Educacio, Investigacio, Cultura i Esport, Generalitat Valenciana (grants AEST/2019/037 and AEST/2020/029) , from the Agencia Valenciana de la Innovacion, Generalitat Valenciana (ref. INNCAD00/19/085) , and from the Centro para el Desarrollo Tecnologico Industrial (Programa Eurostars2, actuacion Interempresas Internacional) , Spanish Ministerio de Ciencia, Innovacion y Universidades (ref. CIIP-20192020) .Pérez-Pelegrí, M.; Monmeneu, JV.; López-Lereu, MP.; Pérez-Pelegrí, L.; Maceira, AM.; Bodi, V.; Moratal, D. (2021). Automatic left ventricle volume calculation with explainability through a deep learning weak-supervision methodology. Computer Methods and Programs in Biomedicine. 208:1-8. https://doi.org/10.1016/j.cmpb.2021.106275S1820

PSPU-Net for Automatic Short Axis Cine MRI Segmentation of Left and Right Ventricles

[EN] Characterization of the heart anatomy and function is mostly done with magnetic resonance image cine series. To achieve a correct characterization, the volume of the right and left ventricle need to be segmented, which is a timeconsuming task. We propose a new convolutional neural network architecture that combines U-net with PSP modules (PSPU-net) for the segmentation of left and right ventricle cavities and left ventricle myocardium in the diastolic frame of short-axis cine MRI images and compare its results against a classic 3D U-net architecture. We used a dataset containing 399 cases in total. The results showed higher quality results in both segmentation and final volume estimation for a test set of 99 cases in the case of the PSPU-net, with global dice metrics of 0.910 and median absolute relative errors in volume estimations of 0.026 and 0.039 for the left ventricle cavity and myocardium and 0.051 for the right ventricles cavity.DM acknowledges financial support from the Conselleria d'Educacio, Investigacio, Cultura i Esport, Generalitat Valenciana (grants AEST/2019/037 and AEST/2020/029), from the Agencia Valenciana de la Innovacion, Generalitat Valenciana (ref. INNCAD00/19/085), and from the Centro para el Desarrollo Tecnologico Industrial (Programa Eurostars-2, actuacion Interempresas Internacional), Spanish Ministerio de Ciencia, Innovacion y Universidades (ref. CIIP20192020). We are grateful to Andres Larroza for his valuable technical assistance in the project.Pérez-Pelegrí, M.; Monmeneu, JV.; López-Lereu, MP.; Ruiz-España, S.; Del-Canto, I.; Bodi, V.; Moratal, D. (2020). PSPU-Net for Automatic Short Axis Cine MRI Segmentation of Left and Right Ventricles. IEEE Computer Society. 1048-1053. https://doi.org/10.1109/BIBE50027.2020.00177S1048105

Prognostic value of cardiac magnetic resonance early after ST-segment elevation myocardial infarction in older patients

[EN] Background older patients with ST-segment elevation myocardial infarction (STEMI) represent a very high-risk population. Data on the prognostic value of cardiac magnetic resonance (CMR) in this scenario are scarce. Methods the registry comprised 247 STEMI patients over 70 years of age treated with percutaneous intervention and included in a multicenter registry. Baseline characteristics, echocardiographic parameters and CMR-derived left ventricular ejection fraction (LVEF, %), infarct size (% of left ventricular mass) and microvascular obstruction (MVO, number of segments) were prospectively collected. The additional prognostic power of CMR was assessed using adjusted C-statistic, net reclassification index (NRI) and integrated discrimination improvement index (IDI). Results during a 4.8-year mean follow-up, the number of first major adverse cardiac events (MACE) was 66 (26.7%): 27 all-cause deaths and 39 re-admissions for acute heart failure. Predictors of MACE were GRACE score (HR 1.03 [1.02-1.04], P 155, LVEF = 2 segments. A simple score (0, 1, 2, 3) based on the number of altered factors accurately predicted the MACE per 100 person-years: 0.78, 5.53, 11.51 and 78.79, respectively (P < 0.001). Conclusions CMR data contribute valuable prognostic information in older patients submitted to undergo CMR soon after STEMI. The Older-STEMI-CMR score should be externally validated.This work was supported by Instituto de Salud Carlos III and Fondos Europeos de Desarrollo Regional FEDER (grant numbers PI20/00637, PI15/00531, and CIBERCV16/11/00486,CIBERCV16/11/00420, CIBERCV16/11/00479), apostgraduate contract FI18/00320 to C.R.-N., CM21/00175 to V.M.-G. and JR21/00041 to C.B., Fundacio La MaratoTV3 (grant 20153030-31-32), La Caixa Banking Foundation (HR17-00527), by Conselleria de Educacion-Generalitat Valenciana (PROMETEO/2021/008) and by Sociedad Espanola de Cardiologia (grant SEC/FEC-INV-CLI 21/024). J.G. acknowledges financial support from the Agencia Estatal de Investigacion (grant FJC2020-043981-I/AEI/10.13039/501100011033). D.M. acknowledges financial support from the Conselleria d'Educacio,Investigacio, Cultura i Esport, Generalitat Valenciana (grants AEST/2019/037, AEST/2020/029).Gabaldón-Pérez A; Marcos-Garcés, V.; Gavara-Doñate, J.; López-Lereu, MP.; Monmeneu, JV.; Pérez, N.; Ríos-Navarro, C.... (2022). Prognostic value of cardiac magnetic resonance early after ST-segment elevation myocardial infarction in older patients. Age and Ageing. 51(11):1-11. https://doi.org/10.1093/ageing/afac248111511

Comparative Analysis of Tagging and Feature-Tracking Cardiac MRI Techniques for the Evaluation of Cardiac Deformation

[EN] Currently, there is a high prevalence of cardiovascular diseases, being the leading cause of mortality worldwide. Thus, a rapid and effective evaluation of the heart is increasingly relevant to diagnose the patient early and achieve appropriate treatment. For this reason, this study aims to compare myocardial deformation parameters such as circumferential strain (segmental, base, mid, apical and global) and global torsion values by the CMR tissue tagging reference technique in SPAMM cine images and the promising feature-tracking technique in b-SSFP cine images, in 31 healthy subjects and 35 patients diagnosed with infarct. The results obtained showed that there is a high agreement in the inter-technique and inter-observer reproducibility for all myocardial parameters evaluated. Therefore, it can be determined the CMR featuretracking technique is highly reproducible for circumferential strain and torsion parameters and could currently be a reliable clinical alternative to assess myocardial function.DM acknowledges financial support from the Conselleria d'Educacio, Investigacio, Cultura i Esport, Generalitat Valenciana (grants AEST/2019/037 and AEST/2020/029), from the Agencia Valenciana de la Innovacion, Generalitat Valenciana (ref. INNCAD00/19/085), and from the Centro para el Desarrollo Tecnologico Industrial (Programa Eurostars-2, Interempresas Internacional), Spanish Ministerio de Ciencia, Innovacion y Universidades (ref. CIIP-20192020).Tejero-Cervera, P.; Del-Canto, I.; López-Lereu, MP.; Monmeneu, JV.; Ruiz-España, S.; Santabárbara, JM.; Maceira, A.... (2020). Comparative Analysis of Tagging and Feature-Tracking Cardiac MRI Techniques for the Evaluation of Cardiac Deformation. IEEE Computer Society. 1054-1059. https://doi.org/10.1109/BIBE50027.2020.00178S1054105

Prognostic implications of dipyridamole cardiac MR imaging: a prospective multicenter registry

Purpose: To evaluate dipyridamole cardiac magnetic resonance (MR) imaging in the prediction of major events (MEs) in patients with ischemic chest pain in a large multicenter registry. Materials and Methods: Institutional ethics committee approval and written informed consent were obtained. A total of 1722 patients who were undergoing cardiac MR imaging for chest pain were included. Wall motion abnormalities (WMAs) at rest, hyperemia perfusion defect (PD), late gadolinium enhancement (LGE), and inducible WMA were analyzed (abnormal if more than one abnormal segment was seen) with the 17-segment model. A cardiac MR categorization was created: category 1, no PD, LGE, or inducible WMA; category 2, PD without LGE and inducible WMA; category 3, LGE without inducible WMA; and category 4, inducible WMA. The association with ME was analyzed by using Cox proportional hazard regression multivariate models. Results: During a median follow-up period of 308 days, 61 MEs (4%) occurred (36 cardiac deaths, 25 nonfatal myocardial infarctions). MEs were associated with a greater extent of WMA, PD, LGE, and inducible WMA (P ¿ .001 for all analyses). In multivariable analyses, PD (P = .002) and inducible WMA (P = .0001) were the only cardiac MR predictors. ME rate in categories 1, 2, 3, and 4 was 2% (14 of 901 patients), 3% (six of 219 patients), 4% (15 of 409 patients), and 14% (26 of 193 patients), respectively (category 4 vs category 1, adjusted P < .001). Cardiac MR¿directed revascularization was performed in 242 patients (14%) and reduced the risk of ME in only category 4 (7% [six of 92 patients] vs 26% [26 of 101 patients], P = .0004). Conclusion: Dipyridamole cardiac MR imaging can be used to predict MEs in patients with ischemic chest pain. Patients with inducible WMA are at the highest risk for MEs and benefit the most from revascularization.Bodi, V.; Husser, O.; Sanchis, J.; Núñez, J.; Monmeneu, JV.; López-Lereu, MP.; Bosch, MJ.... (2012). Prognostic implications of dipyridamole cardiac MR imaging: a prospective multicenter registry. Radiology. 262(1):91-100. doi:10.1148/radiol.11110134S91100262

Resonancia magnética cardiaca de estrés para predecir mortalidad y toma de decisiones: registro de 2.496 pacientes mayores con síndrome coronario crónico

[ES] Introducción y objetivos: El tratamiento del paciente mayor con síndrome coronario crónico (SCC) es un reto. Se exploró el valor pronóstico y la utilidad para la toma de decisiones de la carga isquémica determinada mediante resonancia magnética cardiaca (RMC) de estrés con vasodilatador en pacientes mayores con SCC. Métodos: Se incluyo¿ a 2.496 pacientes mayores de 70 años estudiados con una RMC de estrés con vasodilatador por SCC conocido o sospechado. La carga isquémica (número de segmentos con déficit de perfusión inducido por el estrés) se calculo¿ siguiendo el modelo de 17 segmentos. Posteriormente se analizó de manera retrospectiva su asociación con la mortalidad por cualquier causa y el efecto de la revascularización guiada por la RMC. Resultados: Durante una mediana de seguimiento de 4,58 años, se registraron 430 muertes (17,2%). Una mayor carga isquémica fue un predictor independiente de mortalidad: razón de riesgos, 1,04; intervalos de confianza del 95%, 1,01-1,07 por cada segmento adicional isquémico; p = 0,006). Esta asociación también ocurrió en los mayores de 80 años y en las mujeres (p < 0,001). Se detectó una interacción entre la revascularización y la mortalidad hacia un efecto deletéreo a baja carga isquémica y un efecto protector en caso de isquemia grave.[EN] Introduction and objectives: The management of elderly patients with chronic coronary syndrome (CCS) is challenging. We explored the prognostic value and usefulness for decision-making of ischemic burden determined by vasodilator stress cardiac magnetic resonance (CMR) imaging in elderly patients with known or suspected CCS. Methods: The study group comprised 2496 patients older than 70 years who underwent vasodilator stress CMR for known or suspected CCS. The ischemic burden (number of segments with stress-induced perfusion deficit) was calculated following the 17-segment model. Subsequently, we retrospectively analyzed its association with all-cause mortality and the effect of CMR-guided revascularization. Results: During a median follow-up of 4.58 years, there were 430 deaths (17.2%). A higher ischemic burden was an independent predictor of mortality (HR, 1.04; 95%CI, 1.01-1.07 for each additional ischemic segment; P = .006). This association was also found in patients older than 80 years and in women (P < .001). An interaction between revascularization and mortality was detected toward deleterious consequences at low ischemic burden and a protective effect in patients with extensive ischemia. Conclusions: Vasodilator stress CMR is a valuable tool to stratify risk in elderly patients with CCS and might be helpful to guide decision-making in this scenario.This study has been jointly funded by the Instituto de Salud Carlos III, the Fondo Europeo de Desarrollo Regional (FEDER) and the Sociedad Espanola de Cardiologia and Fundacion Espanola del Corazon [References: PI17/01836, CIBERCV16/11/00486 and SEC/FEC-INV-CLI 21/024].Gabaldón-Pérez, A.; Bonanad, C.; García-Blas, S.; Gavara-Doñate, J.; Ríos-Navarro, C.; Pérez-Solé, N.; De Dios, E.... (2022). Stress cardiac magnetic resonance for mortality prediction and decision-making: registry of 2496 elderly patients with chronic coronary syndrome. Revista Española de Cardiología. 75(3):223-231. https://doi.org/10.1016/j.rec.2021.08.00422323175