Table 2 Logistic regression analysis for Observer 1’s category scores. Observer 2’s category scores are almost identical

Echogenicity

Hyperechoic/isoechoic

5/68 (7 %)

1

Hypoechoic

4/42 (10 %)

1.33 (0.33, 5.24)

Markedly hypoechoic

8/13 (62 %)

20.2 (4.77, 85.2)

Cyst

2/48 (4 %)

0.55 (0.10, 2.95)

<0.001

Contour

Well defined

11/157 (7 %)

1

Borderline/ill-defined

8/14 (57 %)

17.7 (5.21, 60.1)

<0.001

Colour flow

No flow/peripheral flow

0/78 (0 %)

Peripheral > central flow

5/43 (12 %)

Central flow ≥ peripheral flow

14/50 (28 %)

^a

<0.001

Colour flow (grouped)

No flow or peripheral > central flow

5/121 (7 %)

1

Central flow ≥ peripheral flow

14/50 (46 %)

9.02 (3.04, 26.8)

<0.001

Calcification

No

13/157 (8 %)

Coarse

1/9 (11 %)

Microcalcification

5/5 (100 %)

^a

<0.001

Calcification (grouped)

No

13/157 (8 %)

1

Coarse or microcalcification

6/14 (43 %)

6.63 (2.61, 16.8)

0.002