BACKGROUND: Understanding vascular anatomy of the parathyroid glands (PG) is crucial during thyroidectomy. The aim of this study was to describe patterns and distribution of parathyroid vessels. METHOD: An analysis of all intraoperative mapping angiographies from indocyanine green injection and fluorescence imaging in patients undergoing thyroid surgery between February 2020 and September 2021. The parathyroid vessels were classified according to the pattern of contact with the thyroid. Data collection and analysis were carried out in accordance with MR004 reference methodology. RESULTS: A total of 200 angiographies from 196 patients were analysed (159 female/37 male, mean(s.d.) age: 54.2 ± 13.7 years), and 320 PGs were assessed. The parathyroid vessels had no contact with the thyroid in 20 (6%
Type 0), a single-point of contact in 74 (23%
Type 1), a posterior path in 47 (15%
Type 2), a lateral path in 68 (21%
Type 3), an intrathyroidal path in 19 (6%
Type 4), and a possible medial path in 26 (8%
Type X1) cases. The course of the vessels was unclear in 36 cases (11%
Type X2). Spatial distribution analysis showed a concentration of superior parathyroid vessels around Zuckerkandl's tubercle, whereas the distribution of the inferior parathyroid vessels was anterior and sparse. CONCLUSION: Intraoperative mapping angiographies help to define the main patterns of the parathyroid vessels according to their contact with the thyroid and provide surgically useful information about spatial vessel distribution.