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. 2008;2008:419–423.

Table 2.

Definitions and parameters for the sonographic features in our Bayesian classifier.

Sonographic Feature Definition States P(feature|malignant) P(feature|benign)
Microcalcification Punctuate echogenic foci without acoustic shadowing or associated comet-tail artifact Present 0.5 0.1
Absent 0.5 0.9
Shape: Taller than wide AP dimension > transverse dimension Present 0.25 0.05
Absent 0.75 0.95
Margin Margin of the thyroid nodule Smooth 0.15 0.5
Irregular 0.35 0.3
Ill_defined 0.50 0.2
Capsular invasion Extension of a nodule beyond the thyroid capsule Present 0.2 0.0005
Absent 0.8 0.9995
Architecture Composition of the thyroid nodule Solid 0.82 0.5
Almost_solid (<25% cystic) 0.10 0.17
Mixed (25–75% cystic) 0.05 0.17
Cystic (>75% cystic) 0.03 0.16
Echogenicity The echogenicity of the thyroid nodule relative to surrounding thyroid parenchyma Hypoechoic 0.85 0.5
Isoechoic 0.1 0.25
Hyperechoic 0.05 0.25
Ring down artifact Punctuate echogenic foci associated with comet-tail artifact Present 0.00005 0.08
Absent 0.99995 0.92
Vascularity Whether flow is seen on color Doppler interrogation Intrinsic 0.55 0.4
Perinodular 0.44 0.4
avascular 0.01 0.2