587 research outputs found
Computationally efficient cardiac views projection using 3D Convolutional Neural Networks
4D Flow is an MRI sequence which allows acquisition of 3D images of the
heart. The data is typically acquired volumetrically, so it must be reformatted
to generate cardiac long axis and short axis views for diagnostic
interpretation. These views may be generated by placing 6 landmarks: the left
and right ventricle apex, and the aortic, mitral, pulmonary, and tricuspid
valves. In this paper, we propose an automatic method to localize landmarks in
order to compute the cardiac views. Our approach consists of first calculating
a bounding box that tightly crops the heart, followed by a landmark
localization step within this bounded region. Both steps are based on a 3D
extension of the recently introduced ENet. We demonstrate that the long and
short axis projections computed with our automated method are of equivalent
quality to projections created with landmarks placed by an experienced cardiac
radiologist, based on a blinded test administered to a different cardiac
radiologist
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Deep Learning-based Prescription of Cardiac MRI Planes.
PurposeTo develop and evaluate a system to prescribe imaging planes for cardiac MRI based on deep learning (DL)-based localization of key anatomic landmarks.Materials and methodsAnnotated landmarks on 892 long-axis (LAX) and 493 short-axis (SAX) cine steady-state free precession series from cardiac MR images were retrospectively collected between February 2012 and June 2017. U-Net-based heatmap regression was used for localization of cardiac landmarks, which were used to compute cardiac MRI planes. Performance was evaluated by comparing localization distances and plane angle differences between DL predictions and ground truth. The plane angulations from DL were compared with those prescribed by the technologist at the original time of acquisition. Data were split into 80% for training and 20% for testing, and results confirmed with fivefold cross-validation.ResultsOn LAX images, DL localized the apex within mean 12.56 mm ± 19.11 (standard deviation) and the mitral valve (MV) within 7.68 mm ± 6.91. On SAX images, DL localized the aortic valve within 5.78 mm ± 5.68, MV within 5.90 mm ± 5.24, pulmonary valve within 6.55 mm ± 6.39, and tricuspid valve within 6.39 mm ± 5.89. On the basis of these localizations, average angle bias and mean error of DL-predicted imaging planes relative to ground truth annotations were as follows: SAX, -1.27° ± 6.81 and 4.93° ± 4.86; four chambers, 0.38° ± 6.45 and 5.16° ± 3.80; three chambers, 0.13° ± 12.70 and 9.02° ± 8.83; and two chamber, 0.25° ± 9.08 and 6.53° ± 6.28, respectively.ConclusionDL-based anatomic localization is a feasible strategy for planning cardiac MRI planes. This approach can produce imaging planes comparable to those defined by ground truth landmarks.© RSNA, 2019 Supplemental material is available for this article
A Generalizable Deep Learning System for Cardiac MRI
Cardiac MRI allows for a comprehensive assessment of myocardial structure,
function, and tissue characteristics. Here we describe a foundational vision
system for cardiac MRI, capable of representing the breadth of human
cardiovascular disease and health. Our deep learning model is trained via
self-supervised contrastive learning, by which visual concepts in cine-sequence
cardiac MRI scans are learned from the raw text of the accompanying radiology
reports. We train and evaluate our model on data from four large academic
clinical institutions in the United States. We additionally showcase the
performance of our models on the UK BioBank, and two additional publicly
available external datasets. We explore emergent zero-shot capabilities of our
system, and demonstrate remarkable performance across a range of tasks;
including the problem of left ventricular ejection fraction regression, and the
diagnosis of 35 different conditions such as cardiac amyloidosis and
hypertrophic cardiomyopathy. We show that our deep learning system is capable
of not only understanding the staggering complexity of human cardiovascular
disease, but can be directed towards clinical problems of interest yielding
impressive, clinical grade diagnostic accuracy with a fraction of the training
data typically required for such tasks.Comment: 21 page main manuscript, 4 figures. Supplementary Appendix and code
will be made available on publicatio
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