NORMAL PELVIC LYMPH-NODES - EVALUATION WITH CT AFTER BIPEDAL LYMPHANGIOGRAPHY

PURPOSE: To establish guidelines to determine the normal size of pelvi c lymph nodes by correlating computed tomographic (CT) and lymphangiog raphic data. MATERIALS AND METHODS: Forty men in whom stage I testicul ar tumors were being treated underwent CT scanning 3-4 months after un dergoing lymphangiography. The site, size, and number of nodes at CT s canning were documented. Maximum short-axis diameter (MSAD) was measur ed at four anatomic sites in the pelvis. Results were analyzed with hi stograms, and median and percentile values were calculated. RESULTS: T here were 187 nodes measured in 27 men before lymphangiography. There were 1,801 nodes measured in 40 patients after lymphangiography. Media n MSAD values at CT after lymphangiography were 5 mm or less; fewer th an 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. T he low sensitivity of CT in depicting metastases to the pelvic lymph n odes might be improved by adopting upper limits of normal that reflect this size.