title: Benign Solid Thyroid Nodules: US-guided High-Intensity Focused Ultrasound Ablation-Initial Clinical Outcomes.
abstract: OBJECTIVE
  To assess the short-term efficacy and safety of ultrasonographically (US)-guided high-intensity focused ultrasound (HIFU) ablation for treatment of benign solid thyroid nodules.
  
  
  METHODS
  This prospective study was approved by the institutional ethics committee, and written informed consent was acquired. HIFU ablation was performed in one session with US guidance and conscious sedation in 20 euthyroid patients (mean age, 44.5 years) with a benign solitary or dominant thyroid nodule. Thyroid nodule volume, US structure, and Doppler pattern were assessed at baseline, at 1 week, and at 1, 3, and 6 months after treatment. Adverse events associated with HIFU were evaluated. Statistical analysis was conducted by using repeated measures analysis of variance, the Student t test, χ(2) test, and correlation analysis.
  
  
  RESULTS
  The mean ± standard deviation nodule volume was 4.96 mL ± 2.79 at the start of the study. Nodule volume had decreased to 3.05 mL ± 1.96 at the 3-month follow-up examination (n = 20, P < .001), and reached 2.91 mL ± 2.43 by the 6-month follow-up examination (n = 16, P < .001). By then, the mean volume reduction was 48.7% ± 24.3 (P < .001). Isoechoic nodules showed greater reduction at 1 month than did hypoechoic nodules (31.6% ± 18.1 vs 16.4% ± 8.6, P = .053). Nodules with markedly increased blood flow showed smaller volume reduction at 3 months than did less-vascularized nodules (10.9% ± 14.5 vs 41.5% ± 20.3, P = .054). Minor transient complications (eg, subcutaneous edema, mild skin redness) were observed in two patients.
  
  
  CONCLUSIONS
  Early data suggest that US-guided HIFU ablation is an effective and safe procedure for treatment of benign solid thyroid nodules. Initial US echogenicity and vascularization influence the ablation outcome.
authors.affiliation: From the Departments of Thyroid and Metabolic Bone Disorders (R.D.K., J.D.V.) and Endocrine Surgery (J.I.S.), University Hospital of Endocrinology, Medical University Sofia, 2 Zdrave Street, 1431 Sofia, Bulgaria; and Department of Nuclear Medicine, Ljubljana University Medical Center, Ljubljana, Slovenia (K.Z.).
authors.forename: Roussanka D
authors.initials: RD
authors.lastname: Kovatcheva
authors.affiliation: From the Departments of Thyroid and Metabolic Bone Disorders (R.D.K., J.D.V.) and Endocrine Surgery (J.I.S.), University Hospital of Endocrinology, Medical University Sofia, 2 Zdrave Street, 1431 Sofia, Bulgaria; and Department of Nuclear Medicine, Ljubljana University Medical Center, Ljubljana, Slovenia (K.Z.).
authors.forename: Jordan D
authors.initials: JD
authors.lastname: Vlahov
authors.affiliation: From the Departments of Thyroid and Metabolic Bone Disorders (R.D.K., J.D.V.) and Endocrine Surgery (J.I.S.), University Hospital of Endocrinology, Medical University Sofia, 2 Zdrave Street, 1431 Sofia, Bulgaria; and Department of Nuclear Medicine, Ljubljana University Medical Center, Ljubljana, Slovenia (K.Z.).
authors.forename: Julian I
authors.initials: JI
authors.lastname: Stoinov
authors.affiliation: From the Departments of Thyroid and Metabolic Bone Disorders (R.D.K., J.D.V.) and Endocrine Surgery (J.I.S.), University Hospital of Endocrinology, Medical University Sofia, 2 Zdrave Street, 1431 Sofia, Bulgaria; and Department of Nuclear Medicine, Ljubljana University Medical Center, Ljubljana, Slovenia (K.Z.).
authors.forename: Katja
authors.initials: K
authors.lastname: Zaletel
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D057086:High-Intensity Focused Ultrasound Ablation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D014463:Ultrasonography; D055815:Young Adult