Keywords:
Head and neck, PET-CT, Ultrasound, Puncture, Neoplasia
Authors:
C. Alvarez Sánchez1, S. Merino1, M. J. Fernández-Aceñero1, R. Valhondo Rama1, A. VIDAL GONZÁLEZ1, E. Bello Martínez1, T. Ganado Diaz2; 1Madrid/ES, 2Madrid /ES
DOI:
10.26044/ecr2019/C-2146
Methods and materials
Patients:
We retrospectively reviewed 3224 explorations of PET-TC performed at our hospital between 2013 and 2018.
The inclusion criteria were FDG uptake of unless 2 (SUVmax),
focal uptake defined as well-defined FDG uptake in less than one lobe of the thyroid gland and cytological or histological results after ultrasound guided FNA or surgery.
The main exclusion criteria were diffuse FDG uptake,
known previous thyroid disease and different studies from same patients.
Of all these studies one-hundred and fifty-two cases (152) had incidental and focal FDG uptake on thyroid gland; 65 patients underwent US explorations but only in 59 of them FNA was performed.
In conclusion,
59 nodules were included in the study and 93 nodules were excluded from the study because of the absence of ultrasound exploration and/or pathological results.
The range of age of the 59 patients was between 57 and 83 years and the mean age was 68,56; fifteen patients were men and 44 patients were women (Fig.
1).
PET-TC analysis,
thyroid ultrasonography and FNA:
All 18F-FDG PET-CT images were analyzed by one experienced nuclear medicine physician and only one PET-TC scanner was used to acquire the images of all patients,
so there isn´t any possible bias on the comparison of results.
All patients with focal FDG uptake in the thyroid gland on PET-CT underwent thyroid US exploration and it was performed by two expert radiologists.
Multiple US features were registered for all thyroid nodules: location (right thyroid lobe,
left lobe or isthmus); size (<10mm,
10-20mm,
>20mm); echogenicity (hyperechoic,
isoechoic,
or hypoechoic with respect to normal thyroid parenchyma); borders (well or ill-defined); transmission (good or bad); composition (cystic,
solid or mixed) and presence or absence of calcifications (macro or microcalcifications).
Data analysis:
All data was registered and checked for errors using Microsoft Excel 2016 program.
Statistical analysis was done using SPSS 23.0.
Median and quartiles were calculated for continuous variables and percentages for categorical variables.
Mann-Whitney U test was used to compare PET/CT Standardized Uptake Values between the main dependent variable (true malignity by cytology).
Chi-squared tests were performed for categorical variables.
Comparisons with p values > 0.05 were considered significant.
Bivariate analysis was conducted using simple logistic regression.
Correlation between SUVs and Bethesda System was examined using Spearman's rank correlation coefficient.
To assess the optimal threshold and the diagnostic accuracy of SUVs for discriminating malignancy in patients with thyroid PET/CT studies we plotted ROC curves.
We used the optimal SUVs threshold by convenience to divide the dataset and assess the relationship with suspicious or consistent cytopahological malignant results (Bethesda V and VI).