Laser Speckle Contrast Imaging Technique for Assessing Parathyroid Gland Functioning During Thyroidectomy

Laser speckle contrast imaging (LSCI) during thyroidectomy may improve prediction of hypoparathyroidism, as this technique provides surgeons with additional information about parathyroid gland functioning, according to the results of a study published in Thyroid.

Researchers from Vanderbilt University Medical Center recruited 79 patients who were scheduled to undergo thyroidectomy. Following thyroid resection, all accessible parathyroid glands were imaged with the LSCI system. The average speckle contrast was obtained for each gland by segmenting an average image comprising 10 frames. The LSCI technique increased the duration of surgical procedures by approximately 5 minutes.

Most of the patients evaluated were women (78%), mean age was 48.8±13.2 years, and mean body mass index (BMI) was 33.6±8.4 kg/m².  Approximately one-third (29%) had Graves disease, 28% thyroid nodule, 18% papillary thyroid carcinoma, 21% other thyroid cancer, and 4% Hashimoto thyroiditis. Most patients (81%) had undergone total thyroidectomy.

A total of 231 glands were imaged, equating to 2.9 glands per patient. Glands categorized as well-vascularized had an average speckle contrast of 0.11, those categorized as compromised had an average speckle contrast of 0.18, and those considered devascularized had an average speckle contrast of 0.21 (P <.05).

Rates of temporary and permanent hypoparathyroidism were 8.3% and 1.4%, respectively.

After surgery, parathyroid hormone (PTH) levels on day 1 were low (<16 pg/mL) among 8 patients. In addition, 4 of these patients had low serum calcium (<8.4-10.5 mg/dL) levels.

Patients with low postoperative PTH concentrations had significantly higher average parathyroid speckle contrast compared with those who had normal PTH levels (P <10^–4). The optimal speckle contrast value was determined to be 0.186, which best discriminated between patients with low and normal postoperative PTH with a sensitivity of 87.5% and a specificity of 84.4%.

Patients who had no glands with a speckle contrast <0.186 were most likely to have low PTH concentrations on postoperative day 1, with a positive predictive value of 100%. Patients with at least 1 gland with a speckle contrast <0.186 had a negative predictive value of 92.8% for low postoperative PTH.

This study may have been limited as a result of not all glands being imaged or evaluated.

The study authors concluded that the LSCI technique was rapid and effectively provided surgeons with additional information about gland vascularity, predicting postoperative hypoparathyroidism.

Reference

Mannoh EA, Thomas G, Baregamian N, Rohde SL, Solórzano CC, Mahadevan-Jansen A. Assessing intraoperative laser speckle contrast imaging of parathyroid glands in relation to total thyroidectomy patient outcomes. Thyroid. Published online August 18, 2021. doi:10.1089/thy.2021.0093