Features of the popliteal lymph nodes seen on musculoskeletal MRI in a Western population.
OBJECTIVE
To asses the features and explore the clinical relevance of popliteal lymph nodes (PLNs) detected on MRI examination for different pathologies of the knee.


METHODS
A total of 150 knee MRIs, which were conducted for various indications, were retrospectively collected from the Picture Archiving and Communication System. Imaging planes in at least two orthogonal planes were mandatory, with a field of view extending 15 cm cranial from the joint space. The localization of the PLN was determined by measuring the distance of the lowest border of the PLN to the lowest border of the lateral femoral condyle. Clinical diagnosis was obtained from radiology reports and a statistician performed the statistical analysis.


RESULTS
The patients were 70 males [mean age 36.6 years (range: 5-72 years)] and 80 females [mean age 41.1 years (range: 9-76 years)]. In 36.7% of the patients, a PLN was visible. The number of PLNs was negatively associated with age (p < 0.001). The mean number of PLNs was 0.5 PLN per patient. The mean length, height, and width were respectively: 0.57 cm (SD = 0.15), 0.84 cm (SD = 0.26), and 0.71 cm (SD = 0.23). The mean location was 5.8 cm (SD = 1.61). No association was found between the presence of PLNs and internal derangement, inflammation, or cancer (p = 0.368).


CONCLUSIONS
PLNs appearance is age related, with a higher frequency at a young age. The presence of the PLNs showed no relation to a specific clinical situation.
Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Gijsbert.Musters@student.uva.nl
Gijsbert Daniel
GD
Musters
Roeland P
RP
Kleipool
Shandra
S
Bipat
Mario
M
Maas
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007717:Knee / Q000473:pathology*; D008198:Lymph Nodes / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
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