Color Doppler ultrasonography in the evaluation of efficacy of the low-intensity Laser therapy of chronic autoimmune thyroiditis: placebo-controlled randomized clinical trial

INTRODUCTION: A chronic autoimmune thyroiditis (CAT) is the main cause of acquired hypothyroidism which requires continuous treatment with levothyroxine (LT4). So far there has been no such therapy which can make the damaged thyroid tissue regenerate, improving its function. As the low-intensity Laser therapy (LILT) was effective in other autoimmune diseases, as well as in regenerating several tissues, the objective of this study was to evaluate the efficacy of LILT in patients with hypothyroidism caused by CAT by utilizing the following response parameters: A) Color Doppler ultrasonography of thyroid; B) The thyroid function estimated by the dose of LT4 in order to keep the serum concentrations of normal T3, T4, free T4 (fT4) and TSH; C) The serum concentrations of thyroid peroxidase (TPOAb) and thyroglobulin antibodies (TgAb). METHODS: This is a placebo-controlled randomized clinical essay guided at the Institute of Radiology, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo from March 2006 to March 2009, made up of 43 patients with hypothyroidism caused by CAT. All the patients showed high serum concentrations of TPOAb and/or TgAb and ultrasound pattern compatible with CAT. The patients were randomized in L group (submitted to LILT, n = 23) and P group (submitted to placebo, n = 20). The limits of thyroid were marked off with the help of ultrasonography. The patients in L group were submitted to LILT (830 nm) and the patients in P group were submitted to the placebo function of the same equipment. Both groups were submitted a total of 10 sessions, twice a week, using the same technique. Pre- and 30 days post-intervention were applied: ultrasonographic study (US) by B-mode, which included the grey scale computerized histogram to quantitatively estimate the index of echogenicity; the amplitude color Doppler US with values given from 0 to 4 for the vascularization patterns and the pulsed Doppler US to estimate...