Comparison of indocyanine green fluorescence and parathyroid autofluorescence imaging in the identification of parathyroid glands during thyroidectomy

Background: Indocyanine green fluorescence (ICGF) and parathyroid autofluorescence (AF) are two new techniques that aid in the identification of parathyroid glands (PG) intraoperatively during thyroidectomy. There is no study comparing the efficacy of these techniques.

Methods: This was an IRB-approved clinical study comparing the utility of ICGF and AF for identification of PGs during thyroidectomy. Data were collected prospectively. Both techniques were compared to naked eye (NE) for PG detection. Standard statistical methods were used for data analysis.

Results: Twenty-two patients in each group underwent a total of 39 total thyroidectomies and 5 thyroid lobectomies. AF and ICGF had similar detection rates for PGs [98% (61 of 62) and 95% (60 of 63) of PGs, respectively; P=0.31]. The location of PGs was suggested before detection with NE more frequently by AF than ICGF [52% (32 of 62) vs. 6% (4 of 63) of PGs; P<0.001]. In 82% (18 of 22) of patients at least one PG was detected by AF before NE, as opposed to 14% (3 of 22) by ICGF (P<0.001). The median (range) number of PGs detected before NE per patient was greater with AF than ICGF [2 (0-3) vs. 0 (0-2)];. Upper PGs were more likely to be detected by AF before recognition with NE than the lower ones (P=0.03). There was no predictive factor for ICGF detection. Postoperative hypocalcemia rates were similar [9% (2 of 22) and 5% (1 of 22) for AF and ICGF, respectively; P>0.99].

Conclusions: To the best of our knowledge, this is the first comparative study between parathyroid AF and ICGF in detection of PGs during thyroidectomy. Our data suggest both techniques have similarly high detection rates and that the main difference lies in the timing of detection. AF more frequently detects PGs before recognition with NE compared to ICGF.