[Advances in radiological studies of gastrointestinal stromal tumors]

The commonly used radiological examinations for gastrointestinal stromal tumor (GIST) include ultrasound, CT, magnetic resonance imaging and PET, which play important roles in the individualized treatment of GIST through the assistance of the detection, location, diagnose and differential diagnosis, biological behavior and risk evaluation, operation planning, therapeutic effects prediction and follow-up. Standardized predisposal, multi-planar reconstruction and multi-phase enhancement are of great significance in the detection of small GIST lesions. Differences in drainage vessels and enhancement characteristics of tumors are helpful in differentiating small intestinal GIST from pancreatic cancer, neuroendocrine tumors and other abdominal non-GIST tumors. Radiology can provide multiple indicators to qualitatively or quantitatively reflect the risk of GIST. Recent study found that the risk classification of GIST has correlation with necrosis, but not cystic degeneration. The risk stratification of GIST by dual-energy CT showed that CT value and standardized iodine concentration in arterial-venous and delayed phases of high-risk tumors were significantly higher than those of non-high-risk tumors. The correlation between tumor enhancement pattern and risk stratificationwas still controversial. Recently, the rise of radiomics and deep learning techniques provide new direction for risk assessment of GIST. Some studies used various models and parameters to predict the risk classifications of GIST and achieved AUC values above 0.85, and some results were also superior to conventional indicators and radiologists' subjective judgment in the prediction of exon 11 mutations, mitotic counts and survivals. Recent developments in PET and diffusion-weighted MRI provide more precise functional quantitative indicators for the prediction and early evaluation of the response of GIST to targeted therapy. These studies are constantly expanding our field of exploration, and prompting us to stride toward the goal of individualized treatment of GIST.