Inter- and intra-rater reliability of calliper-based lymph node measurement in dogs with peripheral nodal lymphomas

The purpose of this study was to assess reliability of lymph node measurements between and within raters in dogs with nodal lymphomas. Three raters measured lymph nodes from 20 dogs twice prior to and once after administering chemotherapy. Sum tumour volume (TV) and sum longest diameter (LD) of all lymph nodes at each time point, and the percent change in measurements following chemotherapy, were calculated for each dog. Inter- and intra-rater reliability were assessed with the intraclass correlation coefficient (ICC). ICC for inter-rater sum TV and sum LD prior to chemotherapy were 0.86 and 0.80, respectively. ICC for inter-rater sum TV and sum LD after chemotherapy were 0.95 and 0.91, respectively. ICC for percent change in sum TV and sum LD were 0.96 and 0.94, respectively. ICC for intra-rater reliability ranged from 0.90 to 0.98 for each rater. Inter- and intra-rater reliability in measurements among the three raters was good to excellent.