Statistical Analysis
Differences in the means between imaging modalities were assessed using paired t-test. One-way
analysis of variance was used to compare tumor bed volumes among different observers on each
modality. Student's t-test was performed to assess the difference between different subgroups evaluated
by IOV parameters including CIgen and dCOM. The relationships between CVS value and IOV parameters
were measured by Pearson correlation, and the Pearson correlation coefficient (r) was calculated. All data
were analyzed using SPSS (version 22.0), with two-sided significance defined as P < 0.05.
Results
Between August 2018 and March 2019, a total of twenty patients with T1 − 2N0M0 breast cancer were
eligible for this study; all of them underwent full-thickness closure without surgical clips. The median age
of the enrolled patients was 48 years old (range, 33–73), and the median time interval from surgery to CT
was 33.5 days (range, 23–50).
Tumor Bed Volume
Comparisons between the mean volumes of tumor bed on CT and MR modalities contoured by different
observers are shown in Table 1. The mean reductions in the tumor bed volumes from CT to MR were 22%,
27% and 21% for observers 1, 2 and 3, respectively. The differences were highly significant (observers 1, 2
and 3: P = 0.001, P < 0.001 and P = 0.011, respectively). No significant difference was found in the
volumes of tumor bed delineated on CT alone (P = 0.589) or MR alone (P = 0.834) between the different
observers.

### Language ###
English

### Assessment ###
A user might want to know the duration of the study period, which is clearly specified in the results section.

### Query ###
When did the breast cancer study take place?
When did the breast cancer study take place?