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Table 3 Associationa of density estimates (percent density, dense area, and non-dense area) and categoriesb of the four acquisition parameters

From: The influence of mammogram acquisition on the mammographic density and breast cancer association in the mayo mammography health study cohort

 

Spearman correlation coefficient(P value)

Category 1

Category 2

Category 3

  
   

22-25

26-27

28-32

  
 

Cases

(n = 254)c

Subcohort

(n = 1,910)c

Mean

SD

Mean

SD

Mean

SD

  

   Percent density

0.09 (0.15)d

0.04 (0.07)d

17.1

13.8

17.3

14.8

19.0

14.3

  

   Dense area

0.28 (< 0.001)d

0.16 (< 0.001)d

2,070

1,603

2,404

1,864

2,987

2,238

  

   Non-dense area

0.20 (0.002)d

0.16 (< 0.001)d

12,349

6,393

14,386

7,512

15,405

8,289

  
   

Quartile 1

Quartile 2

Quartile 3

Quartile 4

mAs

  

9-126

127-173

174-194

194-371

   

Mean

SD

Mean

SD

Mean

SD

Mean

SD

   Percent density

-0.03 (0.60)

-0.06 (0.008)

18.4

14.3

18.4

14.9

17.1

13.9

16.3

13.3

   Dense area

0.14 (0.02)

0.09 (< 0.001)

1,958

1,481

2,432

1,843

2,415

1,867

2,534

2,086

   Non-dense area

0.24 (< 0.001)

0.25 (< 0.001)

10,906

6,034

13,412

7,284

14,214

7,091

15,404

7,571

   

Quartile 1

Quartile 2

Quartile 3

Quartile 4

Thickness, mm

  

6-45

46-54

55-62

62-94

   Percent density

-0.25 (< 0.001)

-0.27 (< 0.001)

23.3

16.5

17.7

13.2

15.7

12.7

13.0

11.3

   Dense area

-0.01 (0.89)

-0.12 (< 0.001)

2,512

1,846

2,425

1,857

2,261

1,798

2,113

1,844

   Non-dense area

0.41 (< 0.001)

0.35 (< 0.001)

10,211

6,210

13,604

7,142

14,152

6,632

16,236

7,494

   

Quartile 1

Quartile 2

Quartile 3

Quartile 4

Compression force, pounds

 

6.6-21

22-24

25-28

28-49

   Percent density

-0.14 (0.02)

-0.16 (< 0.001)

20.5

15.1

18

14.5

16.9

14.1

14.2

11.6

   Dense area

-0.01 (0.88)

-0.02 (0.39)

2,360

1,761

2,258

1,695

2,407

1,999

2,283

1,880

   Non-dense area

0.26 (< 0.001)

0.31 (< 0.001)

10,859

5,945

12,788

6,749

14,153

6,759

16,536

8,160

  1. aMean and SD of density by categories are estimated using the subcohort only. Correlation coefficients estimated on cases and subcohort separately. bQuartiles were used where appropriate. The distribution of voltage peak (kVp) was highly skewed and was categorized into three levels. cOwing to missing acquisition parameters, 18 cases and 47 controls that were included in the analyses depicted in Table 2 are not included here. dCorrelation coefficients for kVp are based on the three categories and not continuous measures. mAs, milliampere-seconds; SD, standard deviation.