Differentiating malignant from benign thyroid nodules with indeterminate cytology by 99mTc-MIBI scan: a new quantitative method for improving diagnostic accuracy

Abstract

Quantitative 99mTc-MIBI thyroid scintigraphy is a useful tool in differentiating malignant from benign thyroid nodules with indeterminate cytology. The aim of our report is to compare the diagnostic performance of different quantitative methods. We prospectively evaluated 20 patients affected by a thyroid nodule with a cytological diagnosis of class III or IV according to the Bethesda system. Planar images of the thyroid were acquired 10 and 60 minutes after 99mTc-MIBI administration and two different quantitative methods applied (i.e. wash-out index, WOind; retention index, R.I.). All patients underwent lobectomy or thyroidectomy and final histological findings were matched with MIBI results obtained with both quantitative methods. Four out of 20 patients had a final histological result of differentiated thyroid cancer, while benign findings were found in the remaining cases. Overall sensitivity, specificity, accuracy, PPV and NPV were 100% in all for the WOind and 100%, 57.1%, 62.5%, 25% for the R.I., respectively. In conclusion 99mTc-semiquantitative MIBI thyroid scintigraphy with WOind calculation is highly accurate in differential diagnosis of nodules with indeterminate cytology reading.

Personalized management of differentiated thyroid cancer in real life – practical guidance from a multidisciplinary panel of experts

“…Despite such efforts, up to 25% of nodules are still considered to be "cytologically indeterminate", requiring in many cases diagnostic surgery to definitely confirm or exclude malignancy (with a prevalence for malignant nodules of about 30%). Immunocytochemistry, molecular testing (i.e., mutation analysis, microRNA) [12,13], and imaging techniques, including 99m Tcmethoxy-isobutyl-isonitrile (MIBI) scintigraphy and 18 Ffluoro-2-deoxyglucose positron emission tomography/ computed tomography ( 18 F-FDG-PET/CT) [14][15][16][17]…”

Imaging and Imaging-Based Management of Pediatric Thyroid Nodules

“…The main difference between the two parameters lies in the fact that for WOind calculations the uptake within normal thyroid tissue, for which washout is faster than that within nodules, is not taken into account. Quantitative MIBI scintigraphy by evaluating WOind is a useful tool and is documented to be a more accurate method in the management of thyroid nodules with indeterminate cytology [53]. To our knowledge there are no available studies with MIBI on population ≤18 years of age.…”

Galectin-3 Performance in Histologic and Cytologic Assessment of Thyroid Nodules: A Systematic Review and Meta-Analysis

“…As these studies come from the same group, an independent validation should be desirable before proceeding with phase I clinical studies. Notably, other widely employed nuclear medicine procedures (i.e., 99mTc-sestaMIBI scan and 18FDG-PET/CT) already show good accuracy in discriminating cytologically indeterminate nodules [ 77 , 78 , 79 , 80 , 81 ].…”