Mammographic compression in Asian women

Abstract

Objectives: To investigate: (1) the variability of mammographic compression parameters amongst Asian women; and (2) the effects of reducing compression force on image quality and mean glandular dose (MGD) in Asian women based on phantom study.

Methods: We retrospectively collected 15818 raw digital mammograms from 3772 Asian women aged 35-80 years who underwent screening or diagnostic mammography between Jan 2012 and Dec 2014 at our center. The mammograms were processed using a volumetric breast density (VBD) measurement software (Volpara) to assess compression force, compression pressure, compressed breast thickness (CBT), breast volume, VBD and MGD against breast contact area. The effects of reducing compression force on image quality and MGD were also evaluated based on measurement obtained from 105 Asian women, as well as using the RMI156 Mammographic Accreditation Phantom and polymethyl methacrylate (PMMA) slabs.

Results: Compression force, compression pressure, CBT, breast volume, VBD and MGD correlated significantly with breast contact area (p<0.0001). Compression parameters including compression force, compression pressure, CBT and breast contact area were widely variable between [relative standard deviation (RSD)≥21.0%] and within (p<0.0001) Asian women. The median compression force should be about 8.1 daN compared to the current 12.0 daN. Decreasing compression force from 12.0 daN to 9.0 daN increased CBT by 3.3±1.4 mm, MGD by 6.2-11.0%, and caused no significant effects on image quality (p>0.05).

Conclusions: Force-standardized protocol led to widely variable compression parameters in Asian women. Based on phantom study, it is feasible to reduce compression force up to 32.5% with minimal effects on image quality and MGD.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1

(a) Scatter plot showing compression force against contact area (N = 15818). (b) Box plot showing compression force for the left CC (n = 3897), left MLO (n = 3954), right CC (n = 3960) and right MLO views (n = 4007).

Fig 2

(a) Scatter plot showing compression pressure against contact area (N = 15818). (b) Box plot showing compression pressure for the left CC (n = 3897), left MLO (n = 3954), right CC (n = 3960) and right MLO views (n = 4007).

Fig 3

(a) Scatter plot showing compressed breast thickness against contact area (N = 15818). (b) Box plot showing compressed breast thickness for the left CC (n = 3897), left MLO (n = 3954), right CC (n = 3960) and right MLO views (n = 4007).

Fig 4

(a) Scatter plot showing breast volume against contact area (N = 15818). (b) Box plot showing breast volume for the left CC (n = 3897), left MLO (n = 3954), right CC (n = 3960) and right MLO views (n = 4007).

Fig 5

(a) Scatter plot showing volumetric breast density against contact area (N = 15818). (b) Box plot showing volumetric breast density for the left CC (n = 3897), left MLO (n = 3954), right CC (n = 3960) and right MLO views (n = 4007).

Fig 6

(a) Scatter plot showing mean glandular dose against contact area (N = 15818). (b) Box plot showing mean glandular dose for the left CC (n = 3897), left MLO (n = 3954), right CC (n = 3960) and right MLO views (n = 4007).

Fig 7. Box plot showing contact area for the left CC (n = 3897), left MLO (n = 3954), right CC (n = 3960) and right MLO views (n = 4007).

Fig 8. Relationship between the relative mean glandular dose and the thickness of PMMA slabs added to the RMI156 phantom exposed with (a) W/Rh at 28 kVp and (b) W/Ag at 30 kVp.