q-space MR imaging of gastric carcinoma ex vivo: Correlation with histopathologic findings

Purpose: The purpose of this study was to establish the feasibility of q-space imaging (QSI) as a method of assessing the depth of mural invasion, histologic grade, and the presence of lymph node metastasis in gastric carcinomas. Methods: A 7.0 Tesla MR imaging system was used to investigate 20 gastric specimens containing a carcinoma. QSI was performed by using the following parameters: 50–60 mm × 25–30 mm field of view, 2-mm section thickness, 256 × 128 matrix, 10 b values in the 0–7163 s/mm² range, which corresponded to q values of 0–1026/cm, and motion-probing gradients perpendicular to the gastric wall. The MR images and the histopathologic findings were then compared. Results: The depth of tumor invasion of the gastric wall in all 20 carcinomas (100%) was established by using mean displacement, zero-displacement probability, and kurtosis maps. The QSI parameters were significantly correlated with the histologic grades of the gastric carcinomas (all P < 0.001). The QSI parameters made it possible to differentiate between metastatic and nonmetastatic lymph nodes (all P = 0.001). Conclusion: Ex vivo QSI facilitates excellent diagnostics for evaluating gastric carcinomas in terms of mural invasion, histologic grade, and the presence of lymph node metastasis. Magn Reson Med 76:602–612, 2016.