Diagnostics (Jun 2022)

COVLIAS 2.0-cXAI: Cloud-Based Explainable Deep Learning System for COVID-19 Lesion Localization in Computed Tomography Scans

  • Jasjit S. Suri,
  • Sushant Agarwal,
  • Gian Luca Chabert,
  • Alessandro Carriero,
  • Alessio Paschè,
  • Pietro S. C. Danna,
  • Luca Saba,
  • Armin Mehmedović,
  • Gavino Faa,
  • Inder M. Singh,
  • Monika Turk,
  • Paramjit S. Chadha,
  • Amer M. Johri,
  • Narendra N. Khanna,
  • Sophie Mavrogeni,
  • John R. Laird,
  • Gyan Pareek,
  • Martin Miner,
  • David W. Sobel,
  • Antonella Balestrieri,
  • Petros P. Sfikakis,
  • George Tsoulfas,
  • Athanasios D. Protogerou,
  • Durga Prasanna Misra,
  • Vikas Agarwal,
  • George D. Kitas,
  • Jagjit S. Teji,
  • Mustafa Al-Maini,
  • Surinder K. Dhanjil,
  • Andrew Nicolaides,
  • Aditya Sharma,
  • Vijay Rathore,
  • Mostafa Fatemi,
  • Azra Alizad,
  • Pudukode R. Krishnan,
  • Ferenc Nagy,
  • Zoltan Ruzsa,
  • Mostafa M. Fouda,
  • Subbaram Naidu,
  • Klaudija Viskovic,
  • Mannudeep K. Kalra

DOI
https://doi.org/10.3390/diagnostics12061482
Journal volume & issue
Vol. 12, no. 6
p. 1482

Abstract

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Background: The previous COVID-19 lung diagnosis system lacks both scientific validation and the role of explainable artificial intelligence (AI) for understanding lesion localization. This study presents a cloud-based explainable AI, the “COVLIAS 2.0-cXAI” system using four kinds of class activation maps (CAM) models. Methodology: Our cohort consisted of ~6000 CT slices from two sources (Croatia, 80 COVID-19 patients and Italy, 15 control patients). COVLIAS 2.0-cXAI design consisted of three stages: (i) automated lung segmentation using hybrid deep learning ResNet-UNet model by automatic adjustment of Hounsfield units, hyperparameter optimization, and parallel and distributed training, (ii) classification using three kinds of DenseNet (DN) models (DN-121, DN-169, DN-201), and (iii) validation using four kinds of CAM visualization techniques: gradient-weighted class activation mapping (Grad-CAM), Grad-CAM++, score-weighted CAM (Score-CAM), and FasterScore-CAM. The COVLIAS 2.0-cXAI was validated by three trained senior radiologists for its stability and reliability. The Friedman test was also performed on the scores of the three radiologists. Results: The ResNet-UNet segmentation model resulted in dice similarity of 0.96, Jaccard index of 0.93, a correlation coefficient of 0.99, with a figure-of-merit of 95.99%, while the classifier accuracies for the three DN nets (DN-121, DN-169, and DN-201) were 98%, 98%, and 99% with a loss of ~0.003, ~0.0025, and ~0.002 using 50 epochs, respectively. The mean AUC for all three DN models was 0.99 (p < 0.0001). The COVLIAS 2.0-cXAI showed 80% scans for mean alignment index (MAI) between heatmaps and gold standard, a score of four out of five, establishing the system for clinical settings. Conclusions: The COVLIAS 2.0-cXAI successfully showed a cloud-based explainable AI system for lesion localization in lung CT scans.

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