Upper abdominal lymph nodes: criteria for normal size determined with CT

Area of Science:

• Radiology
• Medical Imaging
• Oncology

Background:

• Abdominal lymph node size criteria for computed tomography (CT) vary widely, impacting diagnostic accuracy.
• Existing guidelines lack location-specific upper limits for abdominal lymph nodes, unlike mediastinal nodes.
• Accurate assessment of lymph node size is vital for staging and monitoring various diseases.

Purpose of the Study:

• To establish location-specific upper limits of normal for abdominal lymph node size using CT.
• To provide a standardized reference for interpreting abdominal lymphadenopathy.
• To improve the diagnostic precision of abdominal CT scans.

Main Methods:

• Measurement of short-axis lymph node diameters in 130 patients without suspected lymphadenopathy.
• Definition and analysis of seven distinct abdominal lymph node regions.
• Application of histogram analysis and nonparametric statistics to determine normal size thresholds.

Main Results:

• Defined upper limits for seven abdominal lymph node regions: retrocrural (6 mm), paracardiac (8 mm), gastrohepatic ligament (8 mm), upper paraaortic (9 mm), portacaval (10 mm), porta hepatis (7 mm), and lower paraaortic (11 mm).
• Identified lower paraaortic lymph nodes >11 mm as abnormal.
• Highlighted that nodes <1 cm may be abnormal if exceeding location-specific thresholds.

Conclusions:

• Location-specific upper limits for abdominal lymph node size on CT have been established.
• These thresholds enhance the ability to identify abnormal lymphadenopathy in the abdomen.
• Standardized measurements improve diagnostic accuracy in abdominal imaging.