Description

Gastric cancer is the leading cause of cancer-related death worldwide. The therapeutic approach to gastric cancer is strongly dependent on preoperative stage. The crucial role of gastric cancer imaging lies in implementing individualized treatment regimens according to various stages of tumor.

CT scanning has been recommended as the first-line image modality for preoperative evaluation of gastric cancer by the 8th AJCC staging manual. However, for traditional CT, the accuracy of staging is highly variable and the sensitivity of early gastric cancer detection is relatively low. Recently, DECT has been increasingly used in clinical practice due to its powerful post-processing technique. A recent small sample study showed that monoenergetic images at 40 KeV improved lesion depiction and higher T stage accuracy for gastric cancer. Therefore, this study chose DECT instead of traditional CT to explore the diagnostic performance in preoperative staging.

Historically, the role of MRI in gastric cancer has been limited, and the guidelines have not yet recommended MRI as a first-line examination scheme. But with the continuous technical improvements for abdominal imaging (e.g. breath-hold sequences and high Resolution diffusion-weighted imaging (DWI), free-breathing dynamic contrast-enhanced (DCE) sequence), mpMRI has become a promising imaging technology. In addition, given the advantages of non-radiation, non-invasiveness, and excellent soft tissue contrast, mpMRI may be more suitable for neoadjuvant therapy patients who require multiple evaluations.

Patients with gastric cancer confirmed by endoscopic biopsy will be prospectively included in this study. Patients undergo both mpMRI and DECT at baseline to stage the primary tumor, regional lymph nodes, and to rule out distant sites of disease. The interval between mpMRI and DECT examinations should not exceed 7 days. All patients will be treated according to standard practice in our institution. Patients receiving neoadjuvant chemotherapy will undergo mpMRI and DECT scan again for restaging. The postoperative pathology results of these two examination methods were prospectively collected, and their efficacy was calculated according to the reference standard. After completion of study intervention, patients are followed up periodically.