False-positive and true-negative hilar and mediastinal lymph nodes on FDG-PET--radiological-pathological correlation.
OBJECTIVE
To compare histological findings of FDG-PET false-positive and true-negative hilar and mediastinal lymph nodes.


METHODS
Sixty-seven lymphnode areas in 11 patients who were diagnosed to have N3 lymph nodes by FDG-PET and underwent surgery were histologically examined, and the histopathological findings in false-positive and true-negative lymph nodes were compared. Lymph nodes with higher accumulation of FDG than the surrounding mediastinum level were judged as positive. On histological sections, proportions of macrophages and lymphocytes, amount of coal dust deposit, presence of silicotic nodules, long- and short-axes of the largest node, and volume of macrophages and lymphocytes were evaluated. Correlations between the above-mentioned factors and FDG accumulation were evaluated.


RESULTS
FDG uptake was not correlated with the proportion of macrophages and lymphocytes, coal dust amounts, or the presence of silicotic nodules. The long- and short-axes of the largest node in the false-positive areas were significantly longer than those in the true-negative areas (p = 0.01, and 0.001, respectively). Volumes of lymph nodes (mean +/- SD: 150 +/- 190 mm3) and macrophages (78 +/- 71 mm3) in false-positive areas were markedly larger than those in true-negative areas (68 +/- 87 mm3, p = 0.0009 and 34 +/- 54 mm3, p = 0.0001, respectively). The volume of lymphocytes was also larger in false-positive areas but less markedly.


CONCLUSIONS
Our study suggested that false-positive results of FDG-PET in hilar and mediastinal lymph nodes were closely related to the size of lymph node and the volume of macrophages.
Shiraki
Norio
N
Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Japan. shiraki@med.nagoya-cu.ac.jp
Hara
Masaki
M
Ogino
Hiroyuki
H
Shibamoto
Yuta
Y
Iida
Akihiko
A
Tamaki
Tsuneo
T
Murase
Takayuki
T
Eimoto
Tadaaki
T
D000368:Aged; D002277:Carcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000556:secondary; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis; D008297:Male; D008482:Mediastinum / Q000000981:diagnostic imaging* / Q000473:pathology*; D008875:Middle Aged; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D014055:Tomography, Emission-Computed / Q000379:methods
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18