Single-photon emission computed tomography quantitation of gallium citrate uptake for the differentiation of lymphoma from benign hilar uptake.
OBJECTIVE
To assess the role of quantitative gallium citrate (Ga 67) single-photon emission computed tomography (SPECT) in differentiating lymphoma from benign hilar uptake, concentrations of Ga 67 in 29 sites of documented lymphoma and in 75 benign lesions were compared.


METHODS
One hundred seven thoracic Ga 67 SPECT studies obtained in 101 consecutive lymphoma patients were reviewed. Fifty-nine studies detected Ga 67 uptake in the hilar and or mediastinal regions. Forty-eight studies showed no such abnormality. The concentration of Ga 67 in the thoracic lesions was measured using a quantitative SPECT technique and its nature was determined by correlation with computed tomographic (CT) scans and follow-up evaluation of the sites.


RESULTS
In 20 of 59 abnormal studies (34%), there was lymphoma in the hilar and or mediastinal regions. In the remaining 39 abnormal studies (66%), Ga 67 uptake was benign. There were 29 sites of lymphoma and 75 benign lesions. The concentration of Ga 67 in lymphoma was significantly higher than in benign hilar uptake (13.2 +/- 5.4 %ID/mL x 10(-3) v 5.6 +/- 1.5 % injected dose (ID)/mL x 10(-3); P < .001). A concentration value of 8.3 %ID/mL x 10(-3) was found to best separate lymphoma and benign uptake, with a sensitivity of 90%, a specificity of 93%, a positive predictive value of 84%, and a negative predictive value of 96%.


CONCLUSIONS
Lymphoma and benign hilar uptake differ significantly in their concentration of Ga 67. The present study shows that quantitative Ga-67 SPECT reliably differentiates lymphoma and benign uptake.
Even-Sapir
E
E
Department of Nuclear Medicine, Rambam Medical Center, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.
Bar-Shalom
R
R
Israel
O
O
Frenkel
A
A
Iosilevsky
G
G
Haim
N
N
Epelbaum
R
R
Gaitini
D
D
Kolodny
G M
GM
Front
D
D
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002951:Citrates; D019343:Citric Acid; D005260:Female; D005710:Gallium Radioisotopes; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008223:Lymphoma / Q000000981:diagnostic imaging*; D008297:Male; D008482:Mediastinum / Q000000981:diagnostic imaging; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013899:Thoracic Neoplasms / Q000000981:diagnostic imaging; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D002951:Citrates; D005710:Gallium Radioisotopes; D019343:Citric Acid