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
Results
One-hundred and fifty two focal thyroid FDG uptakes were observed (103 women and 49 men).
Cytopathological results following Bethesda classification were as follows: Bethesda I (unsatisfactory material) in only one of the 59 nodules (US-guided FNA was repeated three times with same results and the nodule remained stable in consecutive US exams along 36 months),
Bethesda II (benign) in 32 nodules,
Bethesda III (uncertain significance atypia) in one nodule,
Bethesda IV (follicular neoplasm or suspicious for follicular neoplasm including follicular variant of papillary thyroid carcinoma) in 9 nodules,
Bethesda V (suspicious for malignant lesion) in 3 patients and Bethesda V category (malignant) in 9 nodules.
Two of these last nodules were metastases,
and one was lymphoma.
Only 10 of 21 patients from categories IV,
V and VI underwent surgical resection: 3 were benign nodules on histology (the three corresponded to Bethesda IV category on previous cytology) and 7 were malignant (2 of them corresponded to category IV,
one to Bethesda V category and 4 nodules had a prior cytological result after FNA of Bethesda VI category)(Fig.
2,3).
The mean SUVmax was 8,875 with a standard deviation (SD) of 5,613.
The median of SUVmax of all nodules was 7.
The mean of SUVmax on nodules with suspicious or consistent cytopathological malignant results (Bethesda V and VI) was 11,583 with a SD of 5,08.
The mean of SUVmax of Bethesda I,II,III,IV nodules was 6,944 with a SD of 3,36.
(Fig.
4).
The comparative analysis of the different ultrasound variables was performed according to the malignancy of the nodule.
There was a statistically significant association between ill-defined borders and marked hypoechogenicity on US and Bethesda V or VI category nodules (p=0,000 and p=0,009 respectively).
The rest of the variables did not show statistically significant results in our study.
Despite not reaching the statistical significance,
a tendency towards malignancy has been evidenced in those nodules that presented localization on left thyroid lobe in our study.
We used the median SUVmax value to dichotomize the SUVmax variable (≤ 7 and >7) and to stablish a SUVmax threshold that indicated or avoided the need of FNA.
P value was statistically significant (0,007),
but OR was not accurate (8,333 with a very wide confidence interval); so these results were not conclusive to stablish 7 or probably any other SUVmax as a threshold for predicting malignancy.
In our study,
a SUV of 8.25 was obtained as a cut-off point proposal based on the COR curve.
This value had 83% of sensitivity and 72% of specificity when related to suspicious or consistent cytopahological malignant results (Bethesda V and VI),
with an AUC of 0.789,
being this significant.