Skip to main content

Table 3 Intra-class correlation coefficient, within-reader and between-woman SD of MD measures to assess repeatability of MD readings, by image format

From: Mammographic density assessed on paired raw and processed digital images and on paired screen-film and digital images across three mammography systems

 

SFM

Raw digital

Processed digital

Measure subset

N obs

N women

N repeats

ICC

Within-reader SD

Between-women SD

N obs

N women

N repeats

ICC

Within-reader SD

Between-women SD

N obs

N women

N repeats

ICC

Within-reader SD

Between-women SD

Percent mammographic densitya

 All

6659

6418

241

0.94

0.42

1.61

1243

1098

145

0.91

0.51

1.64

5009

4627

394

0.89

0.49

1.40

 Reader 1 (H1, H2, G2, F1)

1886

1818

68

0.96

0.38

1.90

346

298

48

0.97

0.33

1.87

1539

1413

126

0.91

0.46

1.51

 Reader 2 (H1, H2, G2, F1)

2464

2381

83

0.92

0.46

1.55

356

309

47

0.79

0.63

1.24

1545

1430

119

0.88

0.48

1.32

 Reader 3 (H1, H2, G2, F1)

2309

2217

92

0.89

0.41

1.17

541

489

52

0.87

0.53

1.39

1925

1775

150

0.86

0.52

1.31

 Hologicb (H1, H2)

      

363

316

47

0.86

0.59

1.48

2742

2517

225

0.87

0.48

1.25

 GEb (G2)

      

590

536

54

0.92

0.54

1.77

1234

1146

88

0.87

0.59

1.49

 Fujib (F1)

      

290

244

46

0.94

0.39

1.47

1033

951

82

0.94

0.39

1.52

Dense areaa

 All sets, all readers

6842

6589

253

0.94

0.48

1.82

1244

1099

145

0.88

0.71

1.95

5021

4616

393

0.85

0.67

1.59

 Reader 1 (H1, H2, G2, F1)

1963

1888

75

0.95

0.45

2.06

346

298

48

0.97

0.40

2.12

1543

1417

126

0.89

0.59

1.66

 Reader 2 (H1, H2, G2, F1)

2568

2482

86

0.93

0.49

1.81

357

310

47

0.71

0.89

1.39

1549

1426

119

0.85

0.64

1.50

 Reader 3 (H1, H2, G2, F1)

2311

2217

94

0.89

0.48

1.41

541

489

52

0.84

0.75

1.72

1929

1778

151

0.80

0.75

1.47

 Hologicb (H1, H2)

      

363

316

47

0.84

0.86

1.94

2745

2520

225

0.83

0.64

1.43

 GEb (G2)

      

591

537

54

0.86

0.75

1.87

1243

1154

89

0.77

0.85

1.53

 Fujib (F1)

      

290

244

46

0.94

0.44

1.82

1033

951

82

0.94

0.50

1.95

Breast areaa

 All

6597

6357

240

1.00

0.14

2.46

1243

1098

145

1.00

0.15

2.53

5009

4616

393

1.00

0.11

2.76

 Reader 1 (H1, H2, G2, F1)

1873

1805

68

1.00

0.10

2.46

346

298

48

1.00

0.06

2.49

1539

1413

126

1.00

0.07

2.74

 Reader 2 (H1, H2, G2, F1)

2442

2359

83

0.99

0.18

2.47

356

309

47

1.00

0.17

2.48

1545

1426

119

1.00

0.10

2.77

 Reader 3 (H1, H2, G2, F1)

2282

2191

91

1.00

0.12

2.46

541

489

52

1.00

0.18

2.59

1925

1775

150

1.00

0.13

2.76

 Hologicb (H1, H2)

      

363

316

47

1.00

0.08

2.13

2742

2517

225

1.00

0.09

2.54

 GEb (G2)

      

590

536

54

0.99

0.19

2.46

1234

1146

88

1.00

0.09

2.53

 Fujib (F1)

      

290

244

46

1.00

0.15

2.73

1033

951

82

1.00

0.15

3.01

  1. Analysis: ICCs, within-reader SD and between-women SD were estimated from a one-way ANOVA using all ICMD measurements and sets H1, H2, G2, F1 and F2. Number of repeats is the number of images read at least twice, by the same or different readers. Reader 4 does not appear here because no repeated readings were available for this reader
  2. Numbers of observations vary by MD measure because only dense area was measured if the breast edge was not visible, and only percent mammographic density if the pixel size was unknown
  3. aAnalysed on a square-root scale
  4. bWithin reader, within image type
  5. Obs observations, SFM Screen-film mammography, ICC Intra-class correlation coefficient, MD Mammographic density, SD Standard deviation, N number of, GE General Electric
Back to article page

Breast Cancer Research

ISSN: 1465-542X

Contact us