Thyroid nodules are a common finding, especially in iodine-deficient regions. Ultrasonographic scoring systems such as Thyroid Imaging Reporting And Data System (TIRADS) are helpful in differentiating between benign and malignant thyroid nodules by offering a risk stratification model. Depending on the constellation or number of suspicious ultrasound features, a fine needle biopsy (FNB) is recommended. However, none of the previously published TIRADS considered the functional status of the nodules. Hyperfunctioning thyroid nodules (HTN) were presumed to exclude malignancy with a very high negative predictive value. Particularly in regions where the iodine supply is lower, the majority of HTN are seen in patients with normal TSH levels. Therefore, thyroid scintigraphy is essential for the detection of HTN. We investigated whether TIRADS identifies HTN as non-suspicious. We evaluated 615 HTN (23.2±10.0 mm at maximum diameter in 582 patients ( = 442 female, 57.7±13.2 years, and = 140 male, 60.1 ±12.7 years) detected byTc Pertechnetate or Iodine scintigraphy. Prior to evaluating the scintigraphic appearance, all nodules were analyzed prospectively with sonography, using the TIRADS model referenced in Kwak et al., wherein fine needle biopsy is recommended for TIRADS 4A or higher. We also investigated two subgroups, 42 nodules with available histology as well as 117 patients with subclinical or overt hyperthyroidism. Whereas 15.9% of the nodules were classified as TIRADS 3 or lower and <0.1% as TIRADS 5, most of the nodules were classified as TIRADS 4A (29.3%), 4B (29.3%), and 4C (24.9%), respectively. Altogether, more than 80% of the autonomous thyroid nodules were classified as TIRADS 4A or higher which would result in a recommendation of fine needle biopsy. Focusing on those 117 HTN that were already associated with hyperthyroid laboratory values, the rates were similar: 81.2% were categorized as TIRADS 4A or higher (4A: 33.3%, 4B: 29.9%, 4C:17.1%, 5: 0.9%). In the subgroup of patients who underwent thyroid surgery, all nodules were benign, confirming the known NPV of HTN with regard to malignancy exclusion. Integration of thyroid scintigraphy into the TIRADS model is essential to prevent unnecessary FNB and thyroid surgery.
This pilot study suggests that, in patients with COM, ed(18)F-NaF -PET offers additional information about early radiotracer distribution to standard (18)F-NaF -PET/CT, similar to a three-phase bone scan. The results should be validated in larger trials which directly compare ed(18)F-NaF-PET to a three-phase bone scan.
In ovo studies are a valuable option in preclinical research, but imaging studies are severely limited by the costs of dedicated equipment needed for small-sized eggs. We sought to verify the feasibility of using larger, ostrich, eggs () for imaging on the PET/CT scanners used for routine clinical investigations. Ostrich eggs were incubated until shortly before hatching, prepared for intravitelline venous injection of contrast medium or radiotracer, and imaged using native CT, contrast-enhanced CT, and PET/CT. Any technical adaptations that were needed to improve the outcome were noted. Of the 34 eggs initially incubated, 12 became fully available for imaging of embryonal development. In ovo imaging with conventional PET/CT not only was feasible but also provided images of good quality, including on dynamic PET imaging. In ovo imaging with ostrich eggs and routine clinical scanners may allow broader application of this field of preclinical research, obviating costly dedicated equipment and reducing the number of animals needed for classic animal research. Further experiments are warranted to refine this novel approach, especially to reduce motion artifacts and improve monitoring of viability.
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