Abstract
Objectives
To determine the optimal inversion time (TI) from Look-Locker scout images using a convolutional neural network (CNN) and to investigate the feasibility of correcting TI using a smartphone.
Methods
In this retrospective study, TI-scout images were extracted using a Look-Locker approach from 1113 consecutive cardiac MR examinations performed between 2017 and 2020 with myocardial late gadolinium enhancement. Reference TI null points were independently determined visually by an experienced radiologist and an experienced cardiologist, and quantitatively measured. A CNN was developed to evaluate deviation of TI from the null point and then implemented in PC and smartphone applications. Images on 4 K or 3-megapixel monitors were captured by a smartphone, and CNN performance on each monitor was determined. Optimal, undercorrection, and overcorrection rates using deep learning on the PC and smartphone were calculated. For patient analysis, TI category differences in pre- and post-correction were evaluated using the TI null point used in late gadolinium enhancement imaging.
Results
For PC, 96.4% (772/749) of images were classified as optimal, with under- and overcorrection rates of 1.2% (9/749) and 2.4% (18/749), respectively. For 4 K images, 93.5% (700/749) of images were classified as optimal, with under- and overcorrection rates of 3.9% (29/749) and 2.7% (20/749), respectively. For 3-megapixel images, 89.6% (671/749) of images were classified as optimal, with under- and overcorrection rates of 3.3% (25/749) and 7.0% (53/749), respectively. On patient-based evaluations, subjects classified as within optimal range increased from 72.0% (77/107) to 91.6% (98/107) using the CNN.
Conclusions
Optimizing TI on Look-Locker images was feasible using deep learning and a smartphone.
Key Points
• A deep learning model corrected TI-scout images to within optimal null point for LGE imaging.
• By capturing the TI-scout image on the monitor with a smartphone, the deviation of the TI from the null point can be immediately determined.
• Using this model, TI null points can be set to the same degree as that by an experienced radiological technologist.
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Abbreviations
- CMR:
-
Cardiac magnetic resonance imaging
- CNN:
-
Convolutional neural network
- DICOM:
-
Digital Imaging and Communications in Medicine
- EDV:
-
End-diastolic volume
- EF:
-
Ejection fraction
- ESV:
-
End-systolic volume
- LGE:
-
Late gadolinium enhancement
- LV:
-
Left ventricle
- PC:
-
Personal computer
- ROI:
-
Region of interest
- SV:
-
Stroke volume
- TI:
-
Inversion time
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Funding
This study was supported by JSPS KAKENHI Grant Number 19K17188.
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The scientific guarantor of this publication is Dr. Tetsuya Fukuda.
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Ohta, Y., Tateishi, E., Morita, Y. et al. Optimization of null point in Look-Locker images for myocardial late gadolinium enhancement imaging using deep learning and a smartphone. Eur Radiol 33, 4688–4697 (2023). https://doi.org/10.1007/s00330-023-09465-8
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DOI: https://doi.org/10.1007/s00330-023-09465-8