Using Machine Learning to Identify Noninvasive Motion-Based Biomarkers of Cardiac Function
This project aims to apply state-of-the-art imaging, motion analysis and machine learning techniques to characterise the motion of the heart as it beats. A population-based, spatio-temporal atlas of cardiac motion has been developed that enables subtle variations in cardiac motion to be identified and quantified. This analysis forms the basis for the development of novel noninvasive biomarkers for the stratification of patients with cardiovascular disease. A notable success to date has been the development of biomarkers that can predict response to cardiac resynchronisation therapy with a success rate of 91% (Peressutti et al, Medical Image Analysis), whilst the current clinical selection criteria result in around one third of patients not responding positively to the treatment. More recent work has focused on the incorporation of multi-modal data into the atlas, in the form of MR and US imaging (Puyol-Anton et al, Medical Image Analysis) and the use of the spatio-temporal atlas to identify the characteristic spatial scales of motion signatures (Sinclair et al, Medical Image Analysis).
- M. Sinclair, D. Peressutti, E. Puyol-Antón, W. Bai, S. Rivolo, J. Webb, S. Claridge, T. Jackson, D. Nordsletten, M. Hadjicharalambous, E. Kerfoot, C. A. Rinaldi, D. Rueckert, A. P. King, "Myocardial Strain Computed at Multiple Spatial Scales from Tagged Magnetic Resonance Imaging: Estimating Cardiac Biomarkers for CRT Patients", Medical Image Analysis 43:169-185, 2017. (open access paper)
- E. Puyol-Antón, M. Sinclair, B. Gerber, M. S. Amzulescu, H. Langet, M. De Craene, P. Aljabar, P. Piro, A. P. King, "A Multimodal Spatiotemporal Cardiac Motion Atlas from MR and Ultrasound Data", Medical Image Analysis 40:96-110, 2017. (open access paper)
- D. Peressutti, M. Sinclair, W. Bai, T. Jackson, J. Ruijsink, D. Nordsletten, L. Asner, M. Hadjicharalambous, C. A. Rinaldi, D. Rueckert, A. P. King, "A Framework for Combining a Motion Atlas with Non-Motion Information to Learn Clinically Useful Biomarkers: Application to Cardiac Resynchronisation Therapy Response Prediction", Medical Image Analysis 35:669-684, 2017. (open access paper)
- E. Puyol-Antón, D. Peressutti, P. Aljabar, M. De Craene, P. Piro and A. P. King, "Towards a Multimodal Cardiac Motion Atlas for Biomarker Extraction", Proceedings ISBI, 2016. (paper)
- M. Sinclair, D. Peressutti, E. Puyol-Antón, W. Bai, D. Nordsletten, M. Hadjicharalambous, E. Kerfoot, T. Jackson, S. Claridge, C. A. Rinaldi, D. Rueckert, and A. P. King, "Learning Optimal Spatial Scales for Cardiac Strain Analysis Using a Motion Atlas", Proceedings MICCAI STACOM, 2016.
- D. Peressutti, W. Bai, T. Jackson, M. Sohal, C. A. Rinaldi, D. Rueckert, and A. P. King, "Prospective Identification of CRT Super Responders Using a Motion Atlas and Random Projection Ensemble Learning", Proceedings MICCAI, 2015. (paper, presentation)
- D. Peressutti, W. Bai, W. Shi, C. Tobon-Gomez, T. Jackson, M. Sohal, A. Rinaldi, D. Rueckert, and A. King, "Towards Left Ventricular Scar Localisation Using Local Motion Descriptors", Proceedings MICCAI STACOM, 2015. (paper)
Automated Quality Control of Cine MR Data From the UK Biobank Data Set
(Funded by EPSRC grant EP/P001009/1)
Recently large-scale databases of imaging and non-imaging data have started to become more widely available. Such databases have great potential for learning more about clinical risk factors and disease processes. The UK Biobank will eventually consist of data from 100,000 volunteers and contains cine and tagged cardiac MR data as well as a wide range of other personal data. However, the size of this database means that it will inevitably contain poor quality data, which could impact upon any analysis performed upon the data unless the poor quality data can be excluded. Manual exclusion is tedious, time-consuming and subject to error. In this work we investigate the use of machine learning techniques for performing automated quality control of cine MR data.
The first technique aims to detect poorly planned 4-chamber cine MR images. One common feature of such images is the presence of the left ventricular outflow tract (LVOT) in the image. We trained a deep convolutional neural network (CNN) on a training set of images featuring good/poor planning. The resulting classifier achieved an accuracy of approximately 83%.
- I. Oksuz, B. Ruijsink, E. Puyol-Antón, M. Sinclair, D. Rueckert, J. A. Schnabel, A. P. King, "Automatic Left Ventricular Outflow Tract Classification for Accurate Cardiac MR Planning", Proceedings ISBI, pp462-465, 2018. (paper)
Subsequent work focused on the presence of motion-related artefacts in the cine MR images. Such artefacts can be caused by mistriggering due to a faulty ECG signal, or by patient breathing during the acquisition. They typically appear as blurring artefacts in the images. Again, UK Biobank data were used to train a CNN classifier to identify these artefacts. However, there is high class imbalance with this problem - there are many more good quality images than artefact images. Class imbalance in training data is known to lead to bias in the performance of the resulting classifier. To address this problem we developed a novel technique for augmenting the training data using synthetically generated artefact images. These images were generated in k-space using a similar process to that which causes the artefacts - by replacing k-space profiles for a specific frame with profiles from different frames. By augmenting the data in this way we were able to achieve 98% classification accuracy with high precision and recall.
- I. Oksuz, B. Ruijsink, E. Puyol-Antón, A. Bustin, G. Cruz, C. Prieto, D. Rueckert, J. A. Schnabel, A. P. King, "Deep Learning using K-space Based Data Augmentation for Automated Cardiac MR Motion Artefact Detection", Proceedings MICCAI, 2018. (Arxiv paper)
Investigating Factors Influencing Cardiac Health From the UK Biobank Data Set
(Funded by EPSRC grant EP/L015226/1)
As an example application of the automated quality control techniques discussed above, we exploited the clinical information contained in the UK Biobank database to investigate factors associated with cardiac health. This involved forming a motion atlas from around 6000 subjects and statistically analysing the links between atlas-derived motion descriptors and the clinical information. Associations were found with body fat percentage, basal metabolic rate, hypertension, smoking status and alcohol intake frequency, and these associations were not identifiable by analysis of the conventional metric of ejection fraction.
- E. Puyol-Antón, B. Ruijsink, H. Langet, M. De Craeme, P.Piro, J. A. Schnabel, A. P. King, "Learning associations between clinical information and motion-based descriptors using a large scale MR-derived cardiac motion atlas", Proceedings MICCAI STACOM, 2018. (Arxiv paper)