Analyzing Tumors by Synthesis

TL;DR

This paper reviews AI methods for generating synthetic tumors in medical images to address data scarcity, demonstrating that synthetic data can improve tumor detection and segmentation performance across various organs.

Contribution

It introduces modeling-based and learning-based tumor synthesis approaches and shows their effectiveness in enhancing AI tumor detection with realistic synthetic data.

Findings

Synthetic tumors are convincingly realistic according to radiologist studies.

AI trained on synthetic tumors can match or outperform models trained on real data.

Tumor synthesis enhances dataset diversity and AI robustness.

Abstract

Computer-aided tumor detection has shown great potential in enhancing the interpretation of over 80 million CT scans performed annually in the United States. However, challenges arise due to the rarity of CT scans with tumors, especially early-stage tumors. Developing AI with real tumor data faces issues of scarcity, annotation difficulty, and low prevalence. Tumor synthesis addresses these challenges by generating numerous tumor examples in medical images, aiding AI training for tumor detection and segmentation. Successful synthesis requires realistic and generalizable synthetic tumors across various organs. This chapter reviews AI development on real and synthetic data and summarizes two key trends in synthetic data for cancer imaging research: modeling-based and learning-based approaches. Modeling-based methods, like Pixel2Cancer, simulate tumor development over time using generic rules, while learning-based methods, like DiffTumor, learn from a few annotated examples in one organ to generate synthetic tumors in others. Reader studies with expert radiologists show that synthetic tumors can be convincingly realistic. We also present case studies in the liver, pancreas, and kidneys reveal that AI trained on synthetic tumors can achieve performance comparable to, or better than, AI only trained on real data. Tumor synthesis holds significant promise for expanding datasets, enhancing AI reliability, improving tumor detection performance, and preserving patient privacy.