Ultrasonographic contrast agent: evaluation of time-intensity curves in the characterisation of solitary thyroid nodules.
OBJECTIVE
To evaluate whether the time-intensity curve can improve characterisation of solitary thyroid nodules.


METHODS
From June to December 2000 we studied 61 patients (16 men and 45 women, mean age 46 years) with solitary thyroid nodules that were not associated with any important hormonal alteration and that showed poor tracer uptake at scintigraphy. We evaluated the Power Doppler vascular pattern before and after a 60" intravenous injection of 2.5 g of Levovist (diluted in 7 ml). The study lasted 5 minutes from the beginning of the infusion. Finally, the time-intensity curves were processed. All the nodules underwent fine needle aspiration biopsy (FNAB) and excision biopsy.


RESULTS
Histology revealed 43 benign lesions and 18 malignant lesions. At contrast-enhanced Power Doppler 83.4% (15/18) of the malignant nodules were found to be hypervascularized, while 16.6% (3/18) were hypovascularized. Of the benign lesions, 90.7% (39/43) were hypervascularized, 9.3% (4/43) were hypovascularized. All the nodules, both hyper- and hypovascularized, displayed rapid and intense wash-in curves. By contrast, the wash-out curves were regular and monophasic in 40/43 (93%) benign lesions (36 hypervascularized and 4 hypovascularized lesions) and irregular and polyphasic in 16/18 (89%) malignant lesions (13 hypervascularized and 3 hypovascularized lesions); 3/43 (7%) benign nodules showed polyphasic wash-out and 2/18 malignant lesions (11%) showed monophasic wash-out.


CONCLUSIONS
Time-intensity curves, and particularly wash-out curves, provide useful information for the characterisation of solitary thyroid nodules. 93% of benign nodules (with regular vascularization) showed a monophasic pattern of the wash-out curve, while 89% of malignant nodules ("anarchical" vascularization) had polyphasic wash-out curves. This behaviour was observed in both hypervascularized and hypovascularized lesions. Our method proved to have a sensitivity of 88% and a specificity of 93%. The study of time-intensity curves could therefore enable us to differentiate between benign and malignant lesions and characterise hypovascularized malignant nodules which would not be observed without contrast agent.
Argalia
G
G
Radiologia Clinica, Università degli Studi, Ancona, Italy.
De Bernardis
S
S
Mariani
D
D
Abbattista
T
T
Taccaliti
A
A
Ricciardelli
L
L
Faragona
S
S
Gusella
P M
PM
Giuseppetti
G M
GM
D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D003287:Contrast Media / Q000493:pharmacokinetics*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011134:Polysaccharides / Q000493:pharmacokinetics*; D012680:Sensitivity and Specificity; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology; D018608:Ultrasonography, Doppler
D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508