Acoustic radiation force impulse imaging for evaluation of the thyroid gland.

OBJECTIVES: To study acoustic radiation force impulse (ARFI) imaging as a new quantitative and noninvasive tool for evaluating thyroid nodules and to compare ARFI imaging with other tools for studying thyroid nodules: sonography, real-time elastography, and fine-needle aspiration biopsy. METHODS: We conducted a prospective study from June 2011 to June 2012, which analyzed 157 thyroid nodules (129 benign and 28 malignant) using the ARFI technique and a 9-MHz probe. Shear wave velocities (SWVs) were obtained while the patients held their breath to avoid respiratory movement artifacts. All nodules underwent conventional sonography and real-time elastography of the thyroid gland. All patients received either a cytologic examination using fine-needle aspiration biopsy or a histologic examination from thyroid surgery to verify the diagnosis (reference standard). RESULTS: The mean SWV ± SD on ARFI imaging in healthy, nodule-free thyroid glands was 2.04 ± 0.51 m/s (range, 0.76-3.63 m/s). The mean SWV in benign thyroid nodules was 1.70 ± 0.55 m/s (range, 0.50-2.80 m/s), and the mean SWV in malignant nodules was 3.39 ± 1.15 m/s (range, 1.50-6.08 m/s). When we used an SWV greater than 2.50 m/s for the diagnosis of malignant nodules and less than 2.50 m/s for the diagnosis of benign nodules, the sensitivity and specificity of ARFI imaging were 85.7% and 96.0%, respectively. CONCLUSIONS: We found that SWVs were substantially higher in malignant nodules than benign ones. Perhaps if ARFI imaging is used in conjunction with sonographic findings and patient demographics, it will be possible to find a combination of factors that would yield a negative predictive value high enough to distinguish benign from malignant nodules with confidence, which may lead to a decrease in the biopsy rate for benign nodules.

Causes and treatment of recurrent hyperparathyroidism after subtotal parathyroidectomy in the presence of multiple endocrine neoplasia 1.

BACKGROUND: Subtotal parathyroidectomy (SPTX) is the treatment of choice for hyperparathyroidism in a patient with multiple endocrine neoplasia type 1 (HPT-MEN-1). There are scarce data on the causes, timing, and appropriate surgical treatment of patients with recurrent HPT-MEN-1. The aim of this study was to investigate the timing, causes, site of recurrence, and surgical treatment of recurrent HPT-MEN-1 in patients who underwent SPTX. METHODS: The study was a retrospective review of prospectively collected data on patients with HPT-MEN-1 with SPTX at two referral institutions. The data collected included the following: demographics, duration of follow-up, weight of resected parathyroid tissue, type of remnant, time to reoperation, cause/site of recurrence, and surgical treatment. We studied prognostic factors of recurrence. RESULTS: A total of 69 patients underwent SPTX and were followed for a mean of 75.3 months. After the surgery, 15 patients were left with a single "normal" gland and 54 with a 50- to 70-mg remnant of a partially excised abnormal gland. Nine patients (13%) had a recurrence within a mean of 85 months (12-144 months). Patients with a recurrence had been followed longer (115 vs. 66 months; p = 0.005). Five recurrences occurred in a parathyroid remnant, 3 in a previously "normal" gland; the fifth recurrence was in both a hyperplastic remnant and a fifth gland. Remedial surgery included five subtotal resections and four immediate parathyroid autotransplantations. Two patients had a second recurrence due to a supernumerary gland. Factors related with recurrence are the follow-up time (p < 0.01) and thymectomy (p < 0.003). CONCLUSIONS: Recurrence of HPTP-MEN-1 usually is located in preserved parathyroid tissue with no preference for a previously normal gland or a remnant. A second recurrence is most likely seen in a supernumerary gland. Recurrence is associated with the follow-up time and thymectomy.