Physiological uptake patterns of gastric lymph node stations on ⁶⁸Ga-pentixafor positron emission tomography (PET):...

The C-X-C motif chemokine receptor 4 (CXCR4)-targeted tracer, ⁶⁸Ga-pentixafor, has shown promise for imaging hematologic malignancies including mucosa-assisted lymphoid tissue (MALT) lymphoma involving lymph nodes (LNs). Its physiological uptake patterns in gastric LN stations remain undefined. This retrospective study aimed to evaluate gastric LN positivity in individuals without known malignancy, establish region-specific references, and explore factors influencing uptake.

Data of patients with hyperaldosteronism who underwent ⁶⁸Ga-pentixafor positron emission tomography/computed tomography (PET/CT) or PET/magnetic resonance (MR) were retrospectively analyzed. Gastric LNs were categorized as perigastric [1-6], near-extragastric [7-9], far-extragastric [10-12], and distant [13-16]. Positive LNs were those with increased ⁶⁸Ga-pentixafor uptake which was higher than that of the blood pool. Reference ranges for maximum standardized uptake value (SUV_max) and LN-to-blood pool SUV ratio (LBR) of each LN station were established. Laboratory data including complete blood count, liver function, hepatitis B virus (HBV) serology, and derived inflammatory indices, were analyzed to identify factors associated with tracer uptake.

A total of 122 patients were included. Physiologically increased uptake was rare in perigastric LNs, only one (0.8%) in LN station 3. In near-extragastric groups, 8a (43.4%) and 8p (22.1%) showed notable uptake. Among far-extragastric LNs, LN station 12p had the highest positivity (86.1%), with a median SUV_max of 4.16 and a LBR of 2.23, respectively. LN station 16a2 had a moderate positivity rate (20.5%). Correlation analysis indicated correlation between the LBR in extragastric groups (LN station 9, 12a, 12b, and 12p) and liver function test parameters (P<0.05), while distant LNs uptake showed no significant laboratory associations except that with alanine aminotransferase (ALT).

Physiological ⁶⁸Ga-pentixafor uptake in gastric LNs is station-specific, notably high in 12p, 8a, and 8p. LN evaluation should integrate uptake and morphology, and larger studies comparing benign and malignant cases are warranted.