The Clinical Role of Dual-Time-Point 18F-FDG PET/CT in Differential Diagnosis of the Thyroid Incidentaloma

Sinae Lee, Taegyu Park, Soyeon Park, Kisoo Pahk, Seunghong Rhee, Jaehyuk Cho, Eugene Jeong, Sungeun Kim, Jae-Gol Choe

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Thyroid incidentalomas are common findings during imaging studies including 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for cancer evaluation. Although the overall incidence of incidental thyroid uptake detected on PET imaging is low, clinical attention should be warranted owing to the high incidence of harboring primary thyroid malignancy. We retrospectively reviewed 2,368 dual-time-point 18F-FDG PET/CT cases that were undertaken for cancer evaluation from November 2007 to February 2009, to determine the clinical impact of dual-time-point imaging in the differential diagnosis of thyroid incidentalomas. Focal thyroid uptake was identified in 64 PET cases and final diagnosis was clarified with cytology/histology in a total of 27 patients with 18F-FDG-avid incidental thyroid lesion. The maximum standardized uptake value (SUVmax) of the initial image (SUV1) and SUVmax of the delayed image (SUV2) were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1 (i.e., RI = [SUV2 - SUV1]/SUV1 × 100). These indices were compared between patient groups that were proven to have pathologically benign or malignant thyroid lesions. There was no statistically significant difference in SUV1 between benign and malignant lesions. SUV2 and RI of the malignant lesions were significantly higher than the benign lesions. The areas under the ROC curves showed that SUV2 and RI have the ability to discriminate between benign and malignant thyroid lesions. The predictability of dual-time-point PET parameters for thyroid malignancy was assessed by ROC curve analyses. When SUV2 of 3.9 was used as cut-off threshold, malignancy on the pathology could be predicted with a sensitivity of 87.5 % and specificity of 75 %. A thyroid lesion that shows RI greater than 12.5 % could be expected to be malignant (sensitivity 88.9 %, specificity 66.3 %). All malignant lesions showed an increase in SUVmax on the delayed images compared with the initial images. But in the group of benign lesions, 37.5 % (6/16) showed a decrease or no change in SUVmax. Dual-time-point 18F-FDG PET/CT, obtaining additional images 2 h after injection, seems to be a complementary method for the differentiation between malignancy and benignity of incidental thyroid lesions.

Original languageEnglish
Pages (from-to)121-129
Number of pages9
JournalNuclear Medicine and Molecular Imaging
Volume48
Issue number2
DOIs
Publication statusPublished - 2014 Jan 1

Fingerprint

Fluorodeoxyglucose F18
Thyroid Gland
Differential Diagnosis
ROC Curve
Neoplasms
Positron Emission Tomography Computed Tomography
Sensitivity and Specificity
Incidence
Area Under Curve
Cell Biology
Histology
Pathology
Injections

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

The Clinical Role of Dual-Time-Point 18F-FDG PET/CT in Differential Diagnosis of the Thyroid Incidentaloma. / Lee, Sinae; Park, Taegyu; Park, Soyeon; Pahk, Kisoo; Rhee, Seunghong; Cho, Jaehyuk; Jeong, Eugene; Kim, Sungeun; Choe, Jae-Gol.

In: Nuclear Medicine and Molecular Imaging, Vol. 48, No. 2, 01.01.2014, p. 121-129.

Research output: Contribution to journalArticle

Lee, Sinae ; Park, Taegyu ; Park, Soyeon ; Pahk, Kisoo ; Rhee, Seunghong ; Cho, Jaehyuk ; Jeong, Eugene ; Kim, Sungeun ; Choe, Jae-Gol. / The Clinical Role of Dual-Time-Point 18F-FDG PET/CT in Differential Diagnosis of the Thyroid Incidentaloma. In: Nuclear Medicine and Molecular Imaging. 2014 ; Vol. 48, No. 2. pp. 121-129.
@article{25966bef111541ce887c52a96832958a,
title = "The Clinical Role of Dual-Time-Point 18F-FDG PET/CT in Differential Diagnosis of the Thyroid Incidentaloma",
abstract = "Thyroid incidentalomas are common findings during imaging studies including 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for cancer evaluation. Although the overall incidence of incidental thyroid uptake detected on PET imaging is low, clinical attention should be warranted owing to the high incidence of harboring primary thyroid malignancy. We retrospectively reviewed 2,368 dual-time-point 18F-FDG PET/CT cases that were undertaken for cancer evaluation from November 2007 to February 2009, to determine the clinical impact of dual-time-point imaging in the differential diagnosis of thyroid incidentalomas. Focal thyroid uptake was identified in 64 PET cases and final diagnosis was clarified with cytology/histology in a total of 27 patients with 18F-FDG-avid incidental thyroid lesion. The maximum standardized uptake value (SUVmax) of the initial image (SUV1) and SUVmax of the delayed image (SUV2) were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1 (i.e., RI = [SUV2 - SUV1]/SUV1 × 100). These indices were compared between patient groups that were proven to have pathologically benign or malignant thyroid lesions. There was no statistically significant difference in SUV1 between benign and malignant lesions. SUV2 and RI of the malignant lesions were significantly higher than the benign lesions. The areas under the ROC curves showed that SUV2 and RI have the ability to discriminate between benign and malignant thyroid lesions. The predictability of dual-time-point PET parameters for thyroid malignancy was assessed by ROC curve analyses. When SUV2 of 3.9 was used as cut-off threshold, malignancy on the pathology could be predicted with a sensitivity of 87.5 {\%} and specificity of 75 {\%}. A thyroid lesion that shows RI greater than 12.5 {\%} could be expected to be malignant (sensitivity 88.9 {\%}, specificity 66.3 {\%}). All malignant lesions showed an increase in SUVmax on the delayed images compared with the initial images. But in the group of benign lesions, 37.5 {\%} (6/16) showed a decrease or no change in SUVmax. Dual-time-point 18F-FDG PET/CT, obtaining additional images 2 h after injection, seems to be a complementary method for the differentiation between malignancy and benignity of incidental thyroid lesions.",
keywords = "Delay scan, Dual-phase PET, Dual-time-point imaging, Retention index, SUVmax, Thyroid incidentaloma",
author = "Sinae Lee and Taegyu Park and Soyeon Park and Kisoo Pahk and Seunghong Rhee and Jaehyuk Cho and Eugene Jeong and Sungeun Kim and Jae-Gol Choe",
year = "2014",
month = "1",
day = "1",
doi = "10.1007/s13139-013-0247-z",
language = "English",
volume = "48",
pages = "121--129",
journal = "Nuclear Medicine and Molecular Imaging",
issn = "1869-3474",
publisher = "Springer Verlag",
number = "2",

}

TY - JOUR

T1 - The Clinical Role of Dual-Time-Point 18F-FDG PET/CT in Differential Diagnosis of the Thyroid Incidentaloma

AU - Lee, Sinae

AU - Park, Taegyu

AU - Park, Soyeon

AU - Pahk, Kisoo

AU - Rhee, Seunghong

AU - Cho, Jaehyuk

AU - Jeong, Eugene

AU - Kim, Sungeun

AU - Choe, Jae-Gol

PY - 2014/1/1

Y1 - 2014/1/1

N2 - Thyroid incidentalomas are common findings during imaging studies including 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for cancer evaluation. Although the overall incidence of incidental thyroid uptake detected on PET imaging is low, clinical attention should be warranted owing to the high incidence of harboring primary thyroid malignancy. We retrospectively reviewed 2,368 dual-time-point 18F-FDG PET/CT cases that were undertaken for cancer evaluation from November 2007 to February 2009, to determine the clinical impact of dual-time-point imaging in the differential diagnosis of thyroid incidentalomas. Focal thyroid uptake was identified in 64 PET cases and final diagnosis was clarified with cytology/histology in a total of 27 patients with 18F-FDG-avid incidental thyroid lesion. The maximum standardized uptake value (SUVmax) of the initial image (SUV1) and SUVmax of the delayed image (SUV2) were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1 (i.e., RI = [SUV2 - SUV1]/SUV1 × 100). These indices were compared between patient groups that were proven to have pathologically benign or malignant thyroid lesions. There was no statistically significant difference in SUV1 between benign and malignant lesions. SUV2 and RI of the malignant lesions were significantly higher than the benign lesions. The areas under the ROC curves showed that SUV2 and RI have the ability to discriminate between benign and malignant thyroid lesions. The predictability of dual-time-point PET parameters for thyroid malignancy was assessed by ROC curve analyses. When SUV2 of 3.9 was used as cut-off threshold, malignancy on the pathology could be predicted with a sensitivity of 87.5 % and specificity of 75 %. A thyroid lesion that shows RI greater than 12.5 % could be expected to be malignant (sensitivity 88.9 %, specificity 66.3 %). All malignant lesions showed an increase in SUVmax on the delayed images compared with the initial images. But in the group of benign lesions, 37.5 % (6/16) showed a decrease or no change in SUVmax. Dual-time-point 18F-FDG PET/CT, obtaining additional images 2 h after injection, seems to be a complementary method for the differentiation between malignancy and benignity of incidental thyroid lesions.

AB - Thyroid incidentalomas are common findings during imaging studies including 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for cancer evaluation. Although the overall incidence of incidental thyroid uptake detected on PET imaging is low, clinical attention should be warranted owing to the high incidence of harboring primary thyroid malignancy. We retrospectively reviewed 2,368 dual-time-point 18F-FDG PET/CT cases that were undertaken for cancer evaluation from November 2007 to February 2009, to determine the clinical impact of dual-time-point imaging in the differential diagnosis of thyroid incidentalomas. Focal thyroid uptake was identified in 64 PET cases and final diagnosis was clarified with cytology/histology in a total of 27 patients with 18F-FDG-avid incidental thyroid lesion. The maximum standardized uptake value (SUVmax) of the initial image (SUV1) and SUVmax of the delayed image (SUV2) were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1 (i.e., RI = [SUV2 - SUV1]/SUV1 × 100). These indices were compared between patient groups that were proven to have pathologically benign or malignant thyroid lesions. There was no statistically significant difference in SUV1 between benign and malignant lesions. SUV2 and RI of the malignant lesions were significantly higher than the benign lesions. The areas under the ROC curves showed that SUV2 and RI have the ability to discriminate between benign and malignant thyroid lesions. The predictability of dual-time-point PET parameters for thyroid malignancy was assessed by ROC curve analyses. When SUV2 of 3.9 was used as cut-off threshold, malignancy on the pathology could be predicted with a sensitivity of 87.5 % and specificity of 75 %. A thyroid lesion that shows RI greater than 12.5 % could be expected to be malignant (sensitivity 88.9 %, specificity 66.3 %). All malignant lesions showed an increase in SUVmax on the delayed images compared with the initial images. But in the group of benign lesions, 37.5 % (6/16) showed a decrease or no change in SUVmax. Dual-time-point 18F-FDG PET/CT, obtaining additional images 2 h after injection, seems to be a complementary method for the differentiation between malignancy and benignity of incidental thyroid lesions.

KW - Delay scan

KW - Dual-phase PET

KW - Dual-time-point imaging

KW - Retention index

KW - SUVmax

KW - Thyroid incidentaloma

UR - http://www.scopus.com/inward/record.url?scp=84901336599&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84901336599&partnerID=8YFLogxK

U2 - 10.1007/s13139-013-0247-z

DO - 10.1007/s13139-013-0247-z

M3 - Article

VL - 48

SP - 121

EP - 129

JO - Nuclear Medicine and Molecular Imaging

JF - Nuclear Medicine and Molecular Imaging

SN - 1869-3474

IS - 2

ER -