Cardiac Radiographic Measurements in Ferrets Using the OsiriX MD Programme

Objectives: To adapt the vertebral heart scale (VHS) for use in ferrets and identify new scales and tools that allow to establish the normal heart size by means of radiography more quickly and effectively. Methods: Forty healthy pet ferrets (Mustela putorius furo) were used in this prospective study. The measurements were made on right lateral, left lateral, ventrodorsal, and dorsoventral projections, using OsiriX MD medical imaging software, to evaluate sex effect and variance within the different heart scales. Cardiac measurements were also correlated to VHS and the cardiac dimension in the same projection. Results: Most of the cardiac measurements were significantly different between males and females. The results for the VHS were: right lateral VHS (RL-VHS): 5.52 ± 0.28 v (vertebrae units); left lateral (LL-VHS): 5.55 ± 0.28 v; and dorsoventral VHS (DV-VHS): 6.22 ± 0.34 v for males and RL-VHS: 5.24 ± 0.2 v; LL-VHS: 5.25 ± 0.20 v; and DV-VHS: 5.97 ± 0.35 v for females. Regarding the sternebral heart scale (SHS), the values were: RL-SHS: 5.10 ± 0.20 s (sternebrae units) and LL-SHS: 5.11 ± 0.20 s for males and RL-SHS: 4.67 ± 0.24 s and LL-SHS: 4.67 ± 0.28 s for females. The new measurements based on determining the cardiac area were also marked by clear sexual dimorphism, as shown for the cardiac area-axis (AREA-AXIS): RL-AREA-AXIS: 3.82 ± 0.45 cm²; LL-AREA-AXIS: 3.87 ± 0.41 cm²; ventrodorsal (VD)-AREA-AXIS: 4.59 ± 0.64 cm²; and DV-AREA-AXIS: 4.80 ± 0.50 cm² for males and RL-AREA-AXIS: 2.39 ± 0.23 cm²; LL-AREA-AXIS: 2.41 ± 0.26 cm²; VD-AREA-AXIS: 3.08 ± 0.45 cm²; and DV-AREA-AXIS: 3.06 ± 0.47 cm² for females. The cardiac area open polygon (AREA-POL) values were: RL-AREA-POL: 6.78 ± 0.65 cm²; LL-AREA-POL: 6.88 ± 0.68 cm²; VD-AREA-POL: 7.20 ± 0.91 cm²; and DV-AREA-POL: 7.57 ± 0.88 cm² for males and RL-AREA-POL: 4.28 ± 0.30 cm²; LL-AREA-POL: 4.35 ± 0.35 cm²; VD-AREA-POL: 4.72 ± 0.65 cm²; and DV-AREA-POL: 4.79 ± 0.66 cm² for females, with similar differences noted from various radiographic projections. A good correlation was noted between VHS and SHS, and a very strongly positive correlation existed between cardiac area measurements and cardiac dimensions. Conclusion: The VHS adapted to ferrets, the SHS, as well as the cardiac area measurements presented in our study are ideal tools for the assessment of cardiac size in ferrets.