(99m)Tc-sestamibi scanning in thyroid nodules with nondiagnostic cytology.
BACKGROUND
Our aim in this study was to assess the relevance of (99m)Tc-sestaMIBI (MIBI) scan in the diagnostic evaluation of thyroid nodules with nondiagnostic cytology.


METHODS
In all, 74 patients with a single nodule and repeatedly nondiagnostic ultrasound-guided fine-needle aspiration cytology (US-FNAC) were enrolled. In all cases thyroid nodules were cold in (99m)Tc-pertechnetate (Tc) scans. Thyroid scans were also acquired 30 and 120 minutes after intravenous administration of MIBI. Nodules that concentrate MIBI were considered as positive (ie, suspicious for malignancy). Histologic findings were obtained after surgery in all patients.


RESULTS
No differences occurred in early and late MIBI images. None of 63 patients with a negative MIBI scan had a final histologic diagnosis of malignancy (ie, no false-negative results). Two patients with a final histologic diagnosis of papillary thyroid carcinoma (PTC) and 1 with follicular thyroid carcinoma (FTC) had a positive MIBI scan. Eight patients with a final histologic diagnosis of benign lesions (3 with follicular adenomas) also had MIBI-positive scans. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were, respectively, 100%, 88%, 89%, 27%, and 100%.


CONCLUSIONS
A negative MIBI scan in a cold nodule accurately excludes malignancy when US-FNAC is reported as nondiagnostic. This avoids the need for more invasive diagnostic procedures (ie, surgery) and positively influences the cost-effectiveness profile. A MIBI scan may be performed by acquiring images 30 minutes after tracer administration alone. Histology is still necessary to distinguish benign from malignant disease in a MIBI-positive nodule but unnecessary surgery could have been reduced from 71 to 8 cases in our series.
Giovanella
Luca
L
Department of Nuclear Medicine, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland. luca.giovanella@eoc.ch
Suriano
Sergio
S
Maffioli
Marco
M
Ceriani
Luca
L
Spriano
Giuseppe
G
D000236:Adenoma / Q000000981:diagnostic imaging; D044963:Biopsy, Fine-Needle; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging; D018265:Carcinoma, Papillary, Follicular / Q000000981:diagnostic imaging; D006801:Humans; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D013959:Thyroid Diseases / Q000000981:diagnostic imaging; D013961:Thyroid Gland / Q000473:pathology; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*; D016606:Thyroid Nodule / Q000000981:diagnostic imaging*; D018084:Ultrasonography, Interventional
D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi