Deep learning-based approach for acquisition time reduction in ventilation SPECT in patients after lung transplantation

Masahiro Nakashima; Ryohei Fukui; Seiichiro Sugimoto; Toshihiro Iguchi

doi:10.1007/s12194-024-00853-3

Deep learning-based approach for acquisition time reduction in ventilation SPECT in patients after lung transplantation

Radiol Phys Technol. 2024 Oct 23. doi: 10.1007/s12194-024-00853-3. Online ahead of print.

Authors

Masahiro Nakashima¹, Ryohei Fukui², Seiichiro Sugimoto³, Toshihiro Iguchi²

Affiliations

¹ Division of Radiological Technology, Okayama University Hospital, 2-5-1 Shikatacho, Kitaku, Okayama, 700-8558, Japan. nakas-m@cc.okayama-u.ac.jp.
² Department of Radiological Technology, Faculty of Health Sciences, Okayama University, 2-5-1 Shikatacho, Kitaku, Okayama, 700-8558, Japan.
³ Department of General Thoracic Surgery and Breast and Endocrinological Surgery, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, 2-5-1 Shikatacho, Kitaku, Okayama, 700-8558, Japan.

PMID: 39441494
DOI: 10.1007/s12194-024-00853-3

Abstract

We aimed to evaluate the image quality and diagnostic performance of chronic lung allograft dysfunction (CLAD) with lung ventilation single-photon emission computed tomography (SPECT) images acquired briefly using a convolutional neural network (CNN) in patients after lung transplantation and to explore the feasibility of short acquisition times. We retrospectively identified 93 consecutive lung-transplant recipients who underwent ventilation SPECT/computed tomography (CT). We employed a CNN to distinguish the images acquired in full time from those acquired in a short time. The image quality was evaluated using the structural similarity index (SSIM) loss and normalized mean square error (NMSE). The correlation between functional volume/morphological volume (F/M) ratios of full-time SPECT images and predicted SPECT images was evaluated. Differences in the F/M ratio were evaluated using Bland-Altman plots, and the diagnostic performance was compared using the area under the curve (AUC). The learning curve, obtained using MSE, converged within 100 epochs. The NMSE was significantly lower (P < 0.001) and the SSIM was significantly higher (P < 0.001) for the CNN-predicted SPECT images compared to the short-time SPECT images. The F/M ratio of full-time SPECT images and predicted SPECT images showed a significant correlation (r = 0.955, P < 0.0001). The Bland-Altman plot revealed a bias of -7.90% in the F/M ratio. The AUC values were 0.942 for full-time SPECT images, 0.934 for predicted SPECT images and 0.872 for short-time SPECT images. Our findings suggest that a deep-learning-based approach can significantly curtail the acquisition time of ventilation SPECT, while preserving the image quality and diagnostic accuracy for CLAD.

Keywords: Chronic lung allograft dysfunction; Convolutional neural network; Deep learning; Lung transplantation; Single photon emission computed tomography.