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.
胃肠间质瘤（GIST）常用的影像学检查手段包括超声、CT、磁共振及正电子发射断层显像（PET），这些检查手段可辅助临床进行病变的检出定位、诊断和鉴别诊断、生物学行为评估及危险度评价、手术方案制定、靶向药物疗效预测及随访监测等，在GIST个体化治疗中发挥着重要作用。规范化前处置、多平面重组及多期增强等技术对GIST小病灶的检出意义较大。肿瘤引流血管及强化特征的差异有助于区分小肠GIST与胰腺癌、神经内分泌肿瘤及其他腹腔非GIST肿块。影像学可提供多种反映GIST危险度的定性定量指标，近期有研究发现，GIST危险度分级与坏死有关，而与囊变无关。双能CT对胃肠道GIST进行危险度分层研究显示，高危险度肿瘤的动静脉期及延迟期CT值及标准化碘浓度值均显著高于非高危险度肿瘤。关于肿瘤强化模式与危险度的关系目前还存在争议。近期影像组学和深度学习研究的兴起，为GIST危险度评价提供了新的方向，多项研究利用各种模型及参数，预测GIST危险度分级AUC值达到0.85以上，预测外显子11突变、核分裂像及生存方面也优于传统指标和医生的主观判断。近期PET及磁共振扩散成像的发展，为GIST靶向治疗疗效的预测和早期评价提供了更为精准的功能定量指标。这些研究都在不断拓宽着临床的探索领域，推动我们向GIST个体化治疗的目标不断迈进。.
Keywords: Diffusion-weighted magnetic resonance imaging; Gastrointestinal stromal tumor; Radiology; Radiomics; Risk classification.