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Adler TJ, Ardizzone L, Vemuri A, Ayala L, Gröhl J, Kirchner T, Wirkert S, Kruse J, Rother C, Köthe U, Maier-Hein L. Uncertainty-aware performance assessment of optical imaging modalities with invertible neural networks. Int J Comput Assist Radiol Surg 2019; 14:997-1007. [PMID: 30903566 DOI: 10.1007/s11548-019-01939-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 03/07/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE Optical imaging is evolving as a key technique for advanced sensing in the operating room. Recent research has shown that machine learning algorithms can be used to address the inverse problem of converting pixel-wise multispectral reflectance measurements to underlying tissue parameters, such as oxygenation. Assessment of the specific hardware used in conjunction with such algorithms, however, has not properly addressed the possibility that the problem may be ill-posed. METHODS We present a novel approach to the assessment of optical imaging modalities, which is sensitive to the different types of uncertainties that may occur when inferring tissue parameters. Based on the concept of invertible neural networks, our framework goes beyond point estimates and maps each multispectral measurement to a full posterior probability distribution which is capable of representing ambiguity in the solution via multiple modes. Performance metrics for a hardware setup can then be computed from the characteristics of the posteriors. RESULTS Application of the assessment framework to the specific use case of camera selection for physiological parameter estimation yields the following insights: (1) estimation of tissue oxygenation from multispectral images is a well-posed problem, while (2) blood volume fraction may not be recovered without ambiguity. (3) In general, ambiguity may be reduced by increasing the number of spectral bands in the camera. CONCLUSION Our method could help to optimize optical camera design in an application-specific manner.
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Affiliation(s)
- Tim J Adler
- Computer Assisted Medical Interventions, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 223, 69120, Heidelberg, Germany. .,Faculty of Mathematics and Computer Science, Heidelberg University, Heidelberg, Germany.
| | | | - Anant Vemuri
- Computer Assisted Medical Interventions, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 223, 69120, Heidelberg, Germany
| | - Leonardo Ayala
- Computer Assisted Medical Interventions, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 223, 69120, Heidelberg, Germany
| | - Janek Gröhl
- Computer Assisted Medical Interventions, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 223, 69120, Heidelberg, Germany.,Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - Thomas Kirchner
- Computer Assisted Medical Interventions, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 223, 69120, Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Sebastian Wirkert
- Computer Assisted Medical Interventions, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 223, 69120, Heidelberg, Germany
| | - Jakob Kruse
- Visual Learning Lab, Heidelberg University, Heidelberg, Germany
| | - Carsten Rother
- Visual Learning Lab, Heidelberg University, Heidelberg, Germany
| | - Ullrich Köthe
- Visual Learning Lab, Heidelberg University, Heidelberg, Germany
| | - Lena Maier-Hein
- Computer Assisted Medical Interventions, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 223, 69120, Heidelberg, Germany
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