Topographic distribution and characteristics of normal gastric regional lymph nodes on diffusion-weighted magnetic resonance imaging

Current lack of recognition of normal gastric regional lymph nodes (GRLNs) and inherent defect of morphological imaging limit the accuracy of preoperative nodal (N) staging of gastric cancer.

To map the distribution of normal GRLNs and evaluating the characteristics of GRLNs with diffusion-weighted imaging (DWI) in healthy population.

Forty-nine enrolled healthy volunteers were divided into two age groups and underwent conventional magnetic resonance imaging (MRI) and DWI examinations. The characteristics of GRLNs in 14 regional stations, including short axis diameter (SD), short-to-long axis diameter ratio (SLR), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC), were recorded and compared between age groups and among different stations.

The normal GRLNs were mainly distributed in station 7 in both age groups, followed by stations 3, 8, and 9. The SLR was lower in the young group than in the old group (P = 0.034) while SD, SNR, CNR, and ADC were significantly higher in the young group compared to the old group, P = 0.045, 0.041, 0.037, and 0.042, respectively. SD was different among stations in both age groups (P = 0.002, 0.001), especially bigger in station 8, and the SNRs and CNRs of stations 8 and 9 were relatively high in the old group (P = 0.031, 0.035), while there was no difference in ADC value.

Better understanding of the appearances of normal GRLNs on conventional MRI and DWI may help to build more appropriate imaging criteria for GRLN assessment in gastric cancer.