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  • Open Access

PB.19. Distortion conspicuity and cancer detection: a comparison of cranio-caudal and mediolateral oblique mammographic projections

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Breast Cancer Research201416 (Suppl 1) :P31

  • Published:


  • Detection Sensitivity
  • Cancer Detection
  • Detection Specificity
  • Breast Malignancy
  • Great Confidence


Mammographic distortions are an indicator of breast malignancy. However, whether distortions and their associated cancers are more readily appreciable on cranio-caudal (CC) or mediolateral oblique (MLO) projection is unexplored. Our study sought to investigate this in view of its potential importance for cancer detection.


A total of 156 mammograms from the South West London Breast Screening Service were anonymised and randomly ordered. The series included 79 consecutive studies with confirmed distortion and 77 normal studies. Three blinded readers were asked to establish the presence of distortion on separately displayed CC and MLO views, and to score distortion conspicuity (1 to 5). Readers also reported the degree of confidence (1 to 5) that identified distortions represented malignancy.


Distortion detection sensitivity was 75% for the CC projection and 64% for the MLO projection (P < 0.005) and specificity was 78% for the CC projection and 84% for MLO (P < 0.05). Cancer detection sensitivity was 86% for the CC projection and 75% for the MLO projection (P = 0.12). Positive predictive values were 0.14 and 0.11 respectively. Cancer detection specificity was 55% for the CC projection and 65% for MLO (P < 0.05). Negative predictive values were 0.98 and 0.97 respectively. In cases of biopsy-proven malignancy, readers were more confident of the presence of cancer on the CC compared with the MLO view (3.05 ± 0.28 vs. 2.22 ± 0.28; P < 0.05).


The CC projection was associated with significantly higher distortion detection and higher cancer detection rate than the MLO view. This view was also associated with greater confidence of identifying proven malignancy amongst readers.

Authors’ Affiliations

St George's Healthcare NHS Trust, London, UK


© George et al.; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.