Synthesizing Quantitative T2 Maps in Right Lateral Knee Femoral Condyles from Multicontrast Anatomic Data with a Conditional Generative Adversarial Network

Bragi Sveinsson; Akshay S Chaudhari; Bo Zhu; Neha Koonjoo; Martin Torriani; Garry E Gold; Matthew S Rosen

doi:10.1148/ryai.2021200122

Synthesizing Quantitative T2 Maps in Right Lateral Knee Femoral Condyles from Multicontrast Anatomic Data with a Conditional Generative Adversarial Network

Radiol Artif Intell. 2021 May 26;3(5):e200122. doi: 10.1148/ryai.2021200122. eCollection 2021 Sep.

Authors

Bragi Sveinsson¹, Akshay S Chaudhari¹, Bo Zhu¹, Neha Koonjoo¹, Martin Torriani¹, Garry E Gold¹, Matthew S Rosen¹

Affiliation

¹ Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 13th St, Suite 2301, Boston, MA 02129 (B.S., B.Z., N.K., M.S.R.); Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Mass (M.T.); Department of Radiology, Stanford University, Stanford, Calif (A.S.C., G.E.G.); and Department of Physics, Harvard University, Cambridge, Mass (M.S.R.).

Abstract

Purpose: To develop a proof-of-concept convolutional neural network (CNN) to synthesize T2 maps in right lateral femoral condyle articular cartilage from anatomic MR images by using a conditional generative adversarial network (cGAN).

Materials and methods: In this retrospective study, anatomic images (from turbo spin-echo and double-echo in steady-state scans) of the right knee of 4621 patients included in the 2004-2006 Osteoarthritis Initiative were used as input to a cGAN-based CNN, and a predicted CNN T2 was generated as output. These patients included men and women of all ethnicities, aged 45-79 years, with or at high risk for knee osteoarthritis incidence or progression who were recruited at four separate centers in the United States. These data were split into 3703 (80%) for training, 462 (10%) for validation, and 456 (10%) for testing. Linear regression analysis was performed between the multiecho spin-echo (MESE) and CNN T2 in the test dataset. A more detailed analysis was performed in 30 randomly selected patients by means of evaluation by two musculoskeletal radiologists and quantification of cartilage subregions. Radiologist assessments were compared by using two-sided t tests.

Results: The readers were moderately accurate in distinguishing CNN T2 from MESE T2, with one reader having random-chance categorization. CNN T2 values were correlated to the MESE values in the subregions of 30 patients and in the bulk analysis of all patients, with best-fit line slopes between 0.55 and 0.83.

Conclusion: With use of a neural network-based cGAN approach, it is feasible to synthesize T2 maps in femoral cartilage from anatomic MRI sequences, giving good agreement with MESE scans.See also commentary by Yi and Fritz in this issue.Keywords: Cartilage Imaging, Knee, Experimental Investigations, Quantification, Vision, Application Domain, Convolutional Neural Network (CNN), Deep Learning Algorithms, Machine Learning Algorithms© RSNA, 2021.

Keywords: Application Domain; Cartilage Imaging; Convolutional Neural Network (CNN); Deep Learning Algorithms; Experimental Investigations; Knee; Machine Learning Algorithms; Quantification; Vision.

2021 by the Radiological Society of North America, Inc.

Grants and funding

K99 AG066815/AG/NIA NIH HHS/United States