Characterization of focal hypermetabolic thyroid incidentaloma: An analysis with F-18 fluorodeoxyglucose positron emission tomography/computed tomography parameters

Table 1 Demographic and clinical characteristics of patients who had abnormal hypermetabolism in the thyroid (n = 339)

Characteristics	Male	Female	Total
Subjects (n)	185	154	339
Age (yr, mean ± SD)	68 ± 11.2	63 ± 15.0	66 ± 13.3
Primary malignancy (n)
Lung	64	33	97 (28.6%)
Colorectal	31	11	42 (12.4%)
Breast	0	50	50 (14.7%)
Lymphoma	15	15	30 (8.8%)
Gastrointestinal	20	8	28 (8.3%)
Hepatobiliary	20	8	28 (8.3%)
Head and neck	13	2	15 (4.4%)
Other	22	27	49 (14.5%)

Table 2 Classification of 46 focal hypermetabolic thyroid lesions as malignant or benign according to the type of primary cancer (n = 46)

Primary cancer	Malignant	Benign	Total
Breast	5	6	11
Kidney	1	0	1
Colorectal	2	3	5
GIST	0	1	1
Lung	8	8	16
Stomach	2	0	2
Uterine cervix	3	0	3
Sarcoma	1	0	1
Urinary bladder	1	0	1
Salivary gland	1	0	1
Lymphoma	1	2	3
Bone	1	0	1
Total	26	20	46

GIST: Gastrointestinal stromal tumor.

Table 3 Examples of F-18 fluorodeoxyglucose positron emission tomography-computed tomography parameters

Parameters	Malignant (n = 26)	Benign (n = 20)	P value
SUVmax	10.8 ± 7.5	6.5 ± 3.0	0.012
SUVpeak	6.8 ± 5.7	4.4 ± 2.0	0.058
MTV2	5.06 ± 5.2	6.7 ± 6.6	0.354
SUVmean2	3.8 ± 1.5	3.0 ± 0.5	0.011
TLG2	25.5 ± 48.9	21.3 ± 24.0	0.735
MTV2.5	3.5 ± 4.5	3.7 ± 4.2	0.872
SUVmean2.5	4.5 ± 1.6	3.6 ± 0.7	0.014
TLG2.5	22.0 ± 47.6	14.8 ± 19.0	0.532

SUV: Standardized uptake value; MTV: Metabolic tumor volume; TLG: Total lesion glycolysis.