Dual time point fluorine-18 fluorodeoxyglucose positron emission tomography: a potential method to differentiate malignancy from inflammation and normal tissue in the head and neck

Abstract

Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) studies imaging FDG PET imaging is used to detect and stage head and neck cancers. However, the variable physiologic uptake of FDG in different normal structures as well as at inflammatory sites may either obscure a tumor focus or be falsely interpreted to represent tumor activity. Twenty-one patients (9 men, 12 women, median age 59) were scanned serially at two time points, one at 70 min (range 47-112) and the second at 98 min (77-142) after the intravenous injection of 4.3 MBq/kg of FDG. The mean interval between emission scans was 28 min (13-49). Transmission scans were performed and regions of interest (ROIs) were overlayed on the fully corrected images. Standardiued uptake values (SUVs) were generated for the cerebellum, tongue, larynx, every lesion, and a matched contralateral site. Follow-up and pathologic studies revealed 18 squamous cell carcinomas and nine inflammatory or infectious lesions. Tumor SUVs were 4.0+/-1.6 (mean +/- SD) for the first scan and 4. 5+/-2.2 for the second scan. Contralateral SUVs were 1.2+/-0.5 and 1. 1+/-0.5 for the two scans. Tumor SUVs increased by 12%+/-12% as compared with a 5%+/-17% decrease for contralateral sites (P<0.05). SUVs for inflammatory sites (2.0+/-0.7 and 2.0+/-0.9), cerebellum (4. 2+/-1.3 and 4.3+/-1.4), tongue (1.8+/-0.4 and 1.9+/-0.5) and larynx (1.5+/-0.6 and 1.5+/-0.6) remained constant over time (+0.6%, +2.8%, +1.4%, and -2.4%; P<0.05 when compared with tumor SUV changes). The ratio tumor/contralateral SUV increased by 23%+/-29% over time while this ratio for inflamed sites increased by only 5%+/-15% (P=0.07). The time interval between scans correlated with increase in SUV for tumors (r=0.55, P<0.05) but not for any of the other ROIs. Separation was superior when studies were performed more than 30 min apart (P<0.05). These preliminary data suggest that dual time point imaging compatible with a clinical study protocol is helpful in differentiating malignant lesions from inflammation and normal tissues, especially when separated by a sufficient time interval.

Usefulness of Additional Delayed Regional F-18 Fluorodeoxy-glucose Positron Emission Tomography in the Lymph Node Staging of Non-Small Cell Lung Cancer Patients

“…Therefore, the maximum WB SUVs and Reg SUVs of some of these primary lung lesions could have been the maximum SUVs of necrotic areas (12). However, previous reports that applied maximum SUVs (8,10,17) or mean SUVs (7,9,11) for data analysis have shown increased SUVs in delayed FDG PET images, although no report mentioned lesion size. In the present study, the correlation between WB SUVS and the size (longest diameter) of the 82 primary lung lesions tended toward negative correlation, but was not statistically significant (r=-0.21, p=0.064).…”

Dual-time point 18FDG-PET/CT imaging may be useful in assessing local recurrent disease in high grade bone and soft tissue sarcoma

“…It has been utilized as an alternative pretreatment imaging method for both soft tissue and bone sarcomas [1,2]. Another use of 18 FDG-PET/CT is evaluation of response to chemotherapy. Definitive treatment of sarcoma is surgical resection.…”

“…Nowadays magnetic resonance tomography (MRT) has a crucial role in identification of local recurrences in soft tissue and bone sarcoma. 18 FDG-PET/CT may serve as a complementary method, searching for metabolic activity in treated regions. The accumulation and metabolism of 18 FDG is dependent on many factors.…”

“…They are a large heterogeneous group of entities with different biological behavior and the clinical diagnosis of such lesions can be very difficult. Molecular imaging with 18 FDG PET/CT (fluoro-deoxyglucose-positron emission tomography with computed tomography) is a powerful modality in oncology. Its use for initial assessment, staging, restaging, evaluation of response to therapy and recurrent disease in most tumors is essential for therapeutic decisions.…”

Peripheral Tuberculous Lymphadenitis Masquerading as Metastatic Gastric Carcinoma on F-18 FDG Dual Time Point PET/CT

“…So, for alternative measure differentiating malignancy from benign disease [5], early standard FDG PET/CT and delayed scan after early scan, namely FDG DTPP, has been introduced and often performed worldwide. FDG DTPP used the phenomenon that with time, FDG uptake in tumor tissues increases, while FDG uptake in normal or benign tissues decreases [5,6]. Although FDG DTPP has been not accepted routinely, the retention index inferred from FDG DTPP predicted patient prognosis in lung cancer [7].…”