Ultrasonographic risk factors of malignancy in thyroid nodules.
BACKGROUND
Between 40 and 50 % of the population will have at least one thyroid nodule, although only 5-8 % will have a malignant one.


OBJECTIVE
The objective of this study was to establish the ultrasonographic characteristics which allow us to distinguish benignity from malignancy in thyroid nodules.


METHODS
In the study population, inclusion criteria are (1) a single thyroid nodule and (2) multinodular goiter and exclusion criteria are (1) previous thyroid surgery and (2) fine needle aspiration (FNA) in the past month. This study is a double-blind prospective study. The study protocol is as follows: (1) clinical study; (2) ultrasound examination; (3) FNA; and (4) surgery-follow-up. The variables analysed are as follows: a multinodular nodule or goitre; colloid degeneration; morphology; margins; hyperechoic rim; rim thickness; rim morphology; size; angle between the major axis and the skin; echostructure; posterior acoustic findings; calcifications; thick colloid; localization of the intrathyroid nodular tissue; and characteristics in the Doppler scan.


RESULTS
A total of 221 thyroid nodules were analysed. The following ultrasound findings were associated with malignancy (p < 0.05): a nodule with posterior acoustic shadowing; the echotexture of the nodule; intranodular colloid degeneration; nodule margins; nodular morphology; the presence of thick colloid; the angle between the major axis and the skin; characteristics of the intranodular vessels using color Doppler and Doppler energy; and calcifications. In the multivariate analysis, the following factors persisted as predictors of malignancy: the echotexture of the nodule (odds ratio 12.81), microcalcifications (OR 9.05), and chaotic vascularisation in the Doppler energy (OR 43.47).


CONCLUSIONS
The high-resolution ultrasound allowed for a more reliable diagnosis of malignancy. The main findings of malignancy were the hypoechogenicity echotexture, microcalcifications, and chaotic intranodular vessels using Doppler energy.
Department of Surgery, Pediatrics and Obstetricians, and Gynecology, University of Murcia, Murcia, Spain. arzrios@um.es.|Service of General Surgery and of the Digestive System, Virgen de la Arrixaca University Hospital, El Palmar, Murcia Health Service, Murcia, Spain. arzrios@um.es.|Murcia Institute of Bio-Health Research at the Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain. arzrios@um.es.|, Avenida de la Libertad n° 208, Casillas, 30007, Murcia, Spain. arzrios@um.es.
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A
Rios
Radiology Service, Virgen de la Arrixaca University Hospital, El Palmar, Murcia Health Service, Murcia, Spain.
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B
Torregrosa
Department of Surgery, Pediatrics and Obstetricians, and Gynecology, University of Murcia, Murcia, Spain.|Service of General Surgery and of the Digestive System, Virgen de la Arrixaca University Hospital, El Palmar, Murcia Health Service, Murcia, Spain.|Murcia Institute of Bio-Health Research at the Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain.
J M
JM
Rodríguez
Radiology Service, Virgen de la Arrixaca University Hospital, El Palmar, Murcia Health Service, Murcia, Spain.
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D
Rodríguez
Radiology Service, Virgen de la Arrixaca University Hospital, El Palmar, Murcia Health Service, Murcia, Spain.
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A
Cepero
Radiology Service, Virgen de la Arrixaca University Hospital, El Palmar, Murcia Health Service, Murcia, Spain.
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MD
Abellán
Service of General Surgery and of the Digestive System, Santa Lucia University Hospital, Cartagena, Murcia Health Service, Murcia, Spain.
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NM
Torregrosa
Service of Endocrinology and Nutrition, Teaching and Continuous Education Unit, Virgen de la Arrixaca University Hospital, El Palmar, Murcia Health Service, Murcia, Spain.
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AM
Hernández
Department of Surgery, Pediatrics and Obstetricians, and Gynecology, University of Murcia, Murcia, Spain.|Service of General Surgery and of the Digestive System, Virgen de la Arrixaca University Hospital, El Palmar, Murcia Health Service, Murcia, Spain.|Murcia Institute of Bio-Health Research at the Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain.
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Parrilla
D000328:Adult; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D012307:Risk Factors; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D018615:Ultrasonography, Doppler, Color
Calcifications; Doppler; Malignancy; Thyroid carcinoma; Thyroid nodule; Ultrasound