Pancreatic neuroendocrine neoplasm:a correlation study between dynamic contrast-enhanced CT and pathological grade

Objective: To investigate the correlation between the dynamic enhanced CT appearances and pathological grading of the pancreatic neuroendocrine neoplasm (pNEN), and to provide radiological evidence for clinical management. Methods: Seventy-four tumors in 72 patients pathologically proven to be pNENs were included, who were admitted to the Fifth Medical Center of Chinese PLA General Hospital between July 2011 and November 2019. The mean age was (49.21 ± 13.84). There were 40 (56%) male cases and 32 (44%) female cases. They were divided into two groups: grades 1 and 2 (Gl/2) group and grade 3 (G3) group. The clinical features and findings on dynamic enhanced CT were compared with the pathological grading. The mean relative density index, and the relative enhancement index of the arterial and venous phases were measured and calculated. Results: There were sixty-three lesions (85%) in 61 patients in G1/2 group, but 11 lesions (15%) in 11 patients in G3 group. The maximum size of the tumors in the two groups was (52.44 ± 26.697) and (46 ± 15.893), respectively. There was statistically significant difference (X² = 9.145, P = 0.002, P < 0.05) between the well-and ill-defined margins, but no significant difference was found in other plain CT findings (all P < 0.05). The relative enhancement indexes in arterial and venous phases were (1.136 ± 0.400) and (1.049 ± 0.311) in the G1/2. group, which were higher than those in G3 group [(0.947 ± 0.604), (0.817 ± 0.380), respectively], and the difference was statistically significant (P < 0.05). However, there was no significant difference in the mean relative density index (Z = -1.314, P = 0.189) between the two groups. Conclusion: The radiological findings of the pNENs on dynamic enhanced CT correlate well with the pathological grading. Tumors with higher pathological grading demonstrate more obscure margins and lower enhancement in arterial and venous phases. (authors)