Artificial Intelligence–assisted chest X-ray assessment scheme for COVID-19

Krithika Rangarajan, Sumanyu Muku, Amit Kumar Garg, Pavan Gabra, Sujay Halkur Shankar, Neeraj Nischal, Kapil Dev Soni, Ashu Seith Bhalla, Anant Mohan, Pawan Tiwari, Sushma Bhatnagar, Raghav Bansal, Atin Kumar, Shivanand Gamanagati, Richa Aggarwal, Upendra Baitha, Ashutosh Biswas, Arvind Kumar, Pankaj Jorwal, ShalimarA. Shariff, Naveet Wig, Rajeshwari Subramanium, Anjan Trikha, Rajesh Malhotra, Randeep Guleria, Vinay Namboodiri, Subhashis Banerjee, Chetan Arora

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Objectives: To study whether a trained convolutional neural network (CNN) can be of assistance to radiologists in differentiating Coronavirus disease (COVID)–positive from COVID-negative patients using chest X-ray (CXR) through an ambispective clinical study. To identify subgroups of patients where artificial intelligence (AI) can be of particular value and analyse what imaging features may have contributed to the performance of AI by means of visualisation techniques. Methods: CXR of 487 patients were classified into [4] categories—normal, classical COVID, indeterminate, and non-COVID by consensus opinion of 2 radiologists. CXR which were classified as “normal” and “indeterminate” were then subjected to analysis by AI, and final categorisation provided as guided by prediction of the network. Precision and recall of the radiologist alone and radiologist assisted by AI were calculated in comparison to reverse transcriptase-polymerase chain reaction (RT-PCR) as the gold standard. Attention maps of the CNN were analysed to understand regions in the CXR important to the AI algorithm in making a prediction. Results: The precision of radiologists improved from 65.9 to 81.9% and recall improved from 17.5 to 71.75 when assistance with AI was provided. AI showed 92% accuracy in classifying “normal” CXR into COVID or non-COVID. Analysis of attention maps revealed attention on the cardiac shadow in these “normal” radiographs. Conclusion: This study shows how deployment of an AI algorithm can complement a human expert in the determination of COVID status. Analysis of the detected features suggests possible subtle cardiac changes, laying ground for further investigative studies into possible cardiac changes. Key Points: • Through an ambispective clinical study, we show how assistance with an AI algorithm can improve recall (sensitivity) and precision (positive predictive value) of radiologists in assessing CXR for possible COVID in comparison to RT-PCR. • We show that AI achieves the best results in images classified as “normal” by radiologists. We conjecture that possible subtle cardiac in the CXR, imperceptible to the human eye, may have contributed to this prediction. • The reported results may pave the way for a human computer collaboration whereby the expert with some help from the AI algorithm achieves higher accuracy in predicting COVID status on CXR than previously thought possible when considering either alone.

Original languageEnglish (US)
Pages (from-to)6039-6048
Number of pages10
JournalEuropean Radiology
Issue number8
StatePublished - Aug 2021

All Science Journal Classification (ASJC) codes

  • Radiology Nuclear Medicine and imaging

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