Purpose: To establish guidelines to determine the normal size of pelvic lymph nodes by correlating computed tomographic (CT) and lymphangiographic data.
Materials and methods: Forty men in whom stage I testicular tumors were being treated underwent CT scanning 3-4 months after undergoing lymphangiography. The site, size, and number of nodes at CT scanning were documented. Maximum short-axis diameter (MSAD) was measured at four anatomic sites in the pelvis. Results were analyzed with histograms, and median and percentile values were calculated.
Results: There were 187 nodes measured in 27 men before lymphangiography. There were 1,801 nodes measured in 40 patients after lymphangiography. Median MSAD values at CT after lymphangiography were 5 mm or less; fewer than 2% of nodes had an MSAD greater than 10 mm.
Conclusion: Almost all normal pelvic nodes are less than 10 mm MSAD, depending on the site. The low sensitivity of CT in depicting metastases to the pelvic lymph nodes might be improved by adopting upper limits of normal that reflect this size.