Evaluation of mediastinal lymph nodes using F-FDG PET-CT scan and its histopathologic correlation.
OBJECTIVE
To determine the efficacy of integrated (18)F-fluorodeoxy glucose positron emission tomography-computed tomography ((18)F-FDG PET-CT) in the evaluation and characterization of mediastinal lymph nodes into benign and malignant pathology.


METHODS
Thirty-five patients with mediastinal lymphadenopathies without primary neoplastic or infective lung pathologies were included in the study. The lymph nodes were detected on contrast-enhanced CT scan of the chest. All patients underwent (18)F-FDG PET-CT scan for evaluation of mediastinal lymph nodes. Results of PET-CT were compared with histopathology of the lymph nodes and sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated.


METHODS
The data were collected prospectively and analyzed using (SPSS Inc., Chicago, IL) 11.5 software.


RESULTS
Histopathology results in 35 patients revealed tuberculosis in 12, sarcoidosis in 8, and lymphoma in 15. Maximum standardized uptake value (SUVmax) of the benign lymph nodes ranged from 2.3 to 11.8 with a mean±standard deviation (SD) of 5.02±3.26. SUVmax of the malignant lymph nodes ranged from 2.4 to 34 with a mean±SD of 10.8±8.12. There was a statistically significant difference between benign and malignant pathology (P<0.0059). (18)F-FDG PET-CT has sensitivity of 93% and specificity of 40% with SUVmax 2.5 as the cutoff. We found the optimal SUVmax cutoff to be 6.2 as determined by the receiver-operator characteristic curve. With 6.2 as cutoff, the sensitivity, specificity, and accuracy were 87%, 70%, and 77%, respectively.


CONCLUSIONS
In countries where tuberculosis and other granulomatous diseases are endemic, SUVmax cutoff value of 2.5 has low specificity. Increasing the cutoff value can improve the specificity, while maintaining an acceptable sensitivity.
Department of Surgical Disciplines, New Delhi, India.
Arvind
A
Kumar
Roman
R
Dutta
Umashankkar
U
Kannan
Rakesh
R
Kumar
Gopi Chand
GC
Khilnani
Siddhartha Datta
SD
Gupta
AJR Am J Roentgenol. 1995 Jun;164(6):1349-59
7754872
Radiology. 1992 Feb;182(2):319-23
1732943
Chin Med J (Engl). 2006 Apr 20;119(8):634-9
16635407
Radiology. 1983 Aug;148(2):357-62
6867325
Arch Med Res. 2008 Jan;39(1):69-77
18067998
Semin Roentgenol. 1985 Oct;20(4):356-75
4071082
Semin Diagn Pathol. 1985 Nov;2(4):281-95
3879948
Clin Microbiol Rev. 2008 Jan;21(1):209-24
18202443
Chest. 2007 Dec;132(6):1949-53
17925421
Radiol Clin North Am. 1982 Sep;20(3):453-68
7111702
Radiology. 2000 Jul;216(1):117-21
10887236
J Nucl Med. 1994 Oct;35(10):1647-9
7931664
Chest. 1996 Apr;109(4):982-8
8635381
Radiology. 1976 Aug;120(2):277-81
935474
Chest. 2003 Jan;123(1 Suppl):137S-146S
12527573
J Thorac Cardiovasc Surg. 2008 Mar;135(3):615-9
18329480
Ann Thorac Surg. 2007 May;83(5):1826-9; discussion 1829-30
17462407