Technetium (99mTc) Macroaggregated Human Serum Albumin

To evaluate whether a radioguided approach allows a higher intraoperative detection rate of adenoma and a minimally invasive parathyroidectomy (MIP), with the same or better cure rate of hyperparathyroidism secondary to parathyroid adenoma.

This was an observational, prospective, single-center study involving 254 consecutive patients with primary hyperparathyroidism, between 2017 and 2022. A total of 258 procedures were performed: 129 non radioguided (NRS) and 129 radioguided (RS) (112 with intravenous 99mTc- MIBI and 17 with ultrasound-guided intralesional 99mTc-MAA injection) with an intraoperative gamma probe and gamma camera. Follow-up was performed for at least one year.

There were no differences between the groups in terms of age, sex, preoperative calcium or parathyroid hormone levels, adenoma localization with 99mTc-MIBI-gammagraphy and ultrasound, and surgical morbidity. Intraoperative surgical localization was 97.7% in both groups. Statistically significant differences supported RS: It allowed to perform MIP (RS: 96.9%, NRS 88.4%; p = 0.015), also in patients with previous neck surgery (RS: 75%, NRS: 28%; p = 0.019) and with ectopic adenomas (RS: 93.3%, NRS: 71.4%; p = 0.012). The operative time was significantly shorter (RS: 51 min, NRS: 59.79 min; p = 0.005). There were no significant differences in the postoperative complications between the groups. Biochemical cure at six months was achieved in RS: 97.7% and NRS: 93.8% (p = 0.12).

Radioguided MIP is useful in ectopic adenomas and in patients with previous cervical surgery and allows a minimally invasive approach more frequently. It is a safe surgery, easily reproducible by an endocrine surgeon and requires usual equipment found in operating rooms.

Limitations in diagnostic test performance are one of the major challenges hampering the eradication of bovine tuberculosis (bTB). Non-tuberculous mycobacteria (NTM) are considered one of the main causes of non-specific reactions in the intradermal tuberculin test, the most widely used bTB diagnostic test. To determine the role of NTMs in bTB misdiagnosis in Spain, an experimental study including the NTM species most commonly found in bTB-positive animals from bTB-free farms in the country (M. avium subsp. avium (Maa), "Mycobacterium avium subsp. hominissuis" (Mah), M. bourgelatii, M. intermedium, M. kansasii and M. nonchromogenicum) was carried out on guinea pigs and cattle. First, guinea pigs were sensitized with the selected NTMs, and six weeks post-sensitization four antigen mixtures (bovine-PPD, avian-PPD, P22 and ESAT6-CFP10) were inoculated intradermally and their effect was measured 24- and 48-h post-inoculation. Larger erythematous reactions were observed in guinea pigs sensitized with Mah, M. kansasii, and Maa, with significant differences in the reactions measured at the bovine-PPD inoculation site for the two first bacteria compared with other NTMs. The sensitization process was repeated in cattle, and five months post-sensitization the same antigen mixtures were inoculated in the cervical region and responses were measured at 48- and 72-h post-inoculation. A significantly higher increase in the skinfold thickness measured at the bovine-PPD inoculation site was observed in calves sensitized with Mah, Maa, M. intermedium and M. kansasii. These results demonstrate that certain NTM species may play a more significant role in bTB diagnostic interferences and show that results obtained in guinea pig and bovine models do not always coincide.