title: Thyroid Nodules Detected by Contrast-Enhanced Magnetic Resonance Angiography: Prevalence and Clinical Significance.
abstract: OBJECTIVE
  Incidental thyroid lesions are frequently found on contrast-enhanced magnetic resonance (CE-MR) angiography. The purpose of this study is to determine the prevalence of thyroid incidentalomas detected by CE-MR angiography and to evaluate their clinical significance by correlation with ultrasound (US) and cytopathological results.
  
  
  METHODS
  We retrospectively reviewed 3,299 consecutive CE-MR angiography examinations performed at our institution between January 2010 and March 2013. Two radiologists evaluated the CE-MR angiography imaging in consensus regarding the presence, location, and vascularity of thyroid incidentaloma. We correlated these findings with follow-up US and cytopathologic results.
  
  
  RESULTS
  The prevalence of thyroid incidentalomas detected by CE-MR angiography was 4.6% (152/3,299 patients). CE-MR angiography showed hypervascularity in 86.8% (145/167), isovascularity in 8.4% (14/167), and hypovascularity in 4.8% (8/167) of thyroid nodules compared to vascularity of thyroid parenchyma. Among the patients with thyroid incidentaloma, 34 patients (22.4%) were followed by US examination, and all 36 nodules on CE-MR angiography were detected on follow-up US. Of these nodules, 9 (25%) nodules were classified as probably benign, 26 (72.2%) as indeterminate, and 1 (2.8%) as suspicious malignant nodule. Among the 16 nodules with available cytopathologic results, 12 nodules were benign, 2 nodules were follicular neoplasm, and 2 nodules showed non-diagnostic results.
  
  
  CONCLUSIONS
  Incidental thyroid nodules were found in 4.6% of CE-MR angiography examinations. Because the high incidence of indeterminate US feature among thyroid incidentaloma, when a thyroid incidentaloma is detected on CE-MR angiography, further evaluation with US should be performed.
authors.affiliation: Department of Radiology, Section of Neuroradiology, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, South Korea.
authors.forename: Hyun Kyung
authors.initials: HK
authors.lastname: Lim
authors.affiliation: Department of Radiology, Section of Neuroradiology, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, South Korea.
authors.forename: Sung Tae
authors.initials: ST
authors.lastname: Park
authors.affiliation: Department of Radiology, Hallym University Medical Center, Hallym University Sacred Heart Hospital, Anyang, South Korea.
authors.forename: Hongil
authors.initials: H
authors.lastname: Ha
authors.affiliation: Department of Radiology, Section of Neuroradiology, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, South Korea.
authors.forename: Seo-youn
authors.initials: SY
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015994:Incidence; D033162:Incidental Findings; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000473:pathology*; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology