Document Type : Research Articles
Medical Image Optimisation and Perception Group (MIOPeG), Discipline of Medical Radiation Sciences, Faculty of Health Sciences, The University of Sydney, Lidcombe NSW, Australia.
Diagnostic Imaging and Radiotherapy Programme, Faculty of Health Sciences, The National University of Malaysia (UKM), Kuala Lumpur, Malaysia.
Rationale and objectives: Target recall rates are often used as a performance indicator in mammography screening
programs with the intention of reducing false positive decisions, over diagnosis and anxiety for participants. However,
the relationship between target recall rates and cancer detection is unclear, especially when readers are directed to
adhere to a predetermined rate. The purpose of this study was to explore the effect of setting different recall rates on
radiologist’s performance. Materials and Methods: Institutional ethics approval was granted and informed consent
was obtained from each participating radiologist. Five experienced breast imaging radiologists read a single test set
of 200 mammographic cases (20 abnormal and 180 normal). The radiologists were asked to identify each case that
they required to be recalled in three different recall conditions; free recall, 15% and 10% and mark the location of any
suspicious lesions. Results: Wide variability in recall rates was observed when reading at free recall, ranging from
18.5% to 34.0%. Readers demonstrated significantly reduced performance when reading at prescribed recall rates,
with lower sensitivity (H=12.891, P=0.002), case location sensitivity (H=12.512, P=0.002) and ROC AUC (H=11.601,
P=0.003) albeit with an increased specificity (H=12.704, P=0.002). However, no significant changes were evident in
lesion location sensitivity (H=1.982, P=0.371) and JAFROC FOM (H=1.820, P=0.403). Conclusion: In this laboratory
study, reducing the number of recalled cases to 10% significantly reduced radiologists’ performance with lower detection
sensitivity, although a significant improvement in specificity was observed.