Objective—To evaluate clinically applicable methods of assessing lean body mass in dogs and compare muscle mass and inflammatory markers in healthy young and old dogs.
Animals—9 healthy young (1 to 5 years old) and 10 old (> 8 years old) Labrador Retrievers with a body condition score of 5 to 6 of 9.
Procedures—Radiography of the thoracolumbar region was performed for measurement of epaxial muscle height at the level of T13–L1. Computed tomographic images were obtained for the measurement of the epaxial and temporal muscles. Ultrasonography also was performed for regional muscle measurements at these same sites and the quadriceps muscle. Serum C-reactive protein, insulin-like growth factor-1, and tumor necrosis factor-α concentrations also were measured, and dogs' activity for 14 days was assessed with an activity monitor.
Results—Mean epaxial muscle area measured by ultrasonography was significantly lower in the old group, compared with the young group, whereas epaxial muscle area measured by CT was only significantly lower in the old group after normalization for vertebral height. Neither temporal and quadriceps muscle measurements nor serum C-reactive protein or insulin-like growth factor-1 concentrations were significantly different between age groups. Tumor necrosis factor-α concentrations were undetectable in all dogs.
Conclusions and Clinical Relevance—This study documented reduced epaxial muscle area in healthy old Labrador Retrievers, consistent with the syndrome of sarcopenia. Ultrasonography and CT were feasible methods of measuring epaxial muscle area, but much additional research is required to assess this method. A better understanding of underlying mechanisms of sarcopenia as well as methods for slowing progression is needed.
OBJECTIVE To evaluate use of an ultrasonographically and radiographically determined value, the vertebral epaxial muscle score (VEMS), for assessing muscle mass in cats.
ANIMALS 30 healthy neutered cats of various body weights and between 1 and 6 years of age.
PROCEDURES Mean epaxial muscle height was calculated from 3 transverse ultrasonographic images obtained at the level of T13. Length of T4 was measured on thoracic radiographs, and the VEMS (ratio of epaxial muscle height to T4 length) was calculated and compared with body weight. Ratios of epaxial muscle height to various anatomic measurements also were compared with body weight as potential alternatives to use of T4 length.
RESULTS 1 cat was excluded because of a heart murmur. For the remaining 29 cats, mean ± SD body weight was 5.05 ± 1.40 kg. Mean epaxial muscle height was 1.27 ± 0.13 cm, which was significantly correlated (r = 0.65) with body weight. The VEMS and value for epaxial muscle height/(0.1 × forelimb circumference) were not significantly correlated (r = −0.18 and −0.06, respectively) with body weight, which is important for measures used for animals of various sizes.
CONCLUSIONS AND CLINICAL RELEVANCE The VEMS and value for epaxial muscle height/(0.1 × forelimb circumference) can both be used to normalize muscle size among cats of various body weights. Studies are warranted to determine whether these values can be used to accurately assess muscle mass in cats with various adiposity and in those with muscle loss.
To compare muscle condition scores (MCSs) and muscle ultrasonographic measurements in cats with and without muscle loss and to evaluate repeatability and reproducibility of MCS assessment.
40 cats of various ages, body condition scores (BCSs), and MCSs.
A prospective cross-sectional study was conducted. Body weight, BCS, MCS, epaxial muscle height (EMH), vertebral epaxial muscle score (VEMS), and forelimb epaxial muscle score (FLEMS) were assessed in each cat. The MCS for each cat was assessed 3 separate times by each of 5 raters.
The MCS was significantly correlated with EMH (r = 0.59), VEMS (r = 0.66), and FLEMS (r = 0.41). For MCS, the overall value of the κ coefficient for interrater agreement (reproducibility) was 0.43 and the overall value of the κ coefficient for intrarater agreement (repeatability) ranged from 0.49 to 0.76.
CONCLUSIONS AND CLINICAL RELEVANCE
Ultrasonographic measurements of muscle may be useful for assessing muscle loss in individual cats over time. However, for the cats of this study, no advantage was observed for assessment of VEMS or FLEMS over EMH. Substantial repeatability and moderate reproducibility were shown when MCS was used for assessment of muscle mass in cats. Prospective ultrasonographic studies are warranted to evaluate the usefulness of MCS and EMH assessment for evaluation of changes in muscle mass of cats over time.
To evaluate repeatability and reproducibility of muscle condition score (MCS) in dogs with various degrees of muscle loss; to compare MCS, muscle ultrasonographic measurements, and quantitative magnetic resonance (QMR) measurements; and to identify cutoff values for ultrasonographic measurements of muscle that can be used to identify dogs with cachexia and sarcopenia.
40 dogs of various age, body condition score (BCS), and MCS.
A prospective cross-sectional study was conducted. Body weight, BCS, QMR measurements, thoracic radiographic measurements, and muscle ultrasonographic measurements were assessed once in each dog. The MCS for each dog was assessed 3 separate times by 4 separate raters.
For the MCS, overall κ for interrater agreement was 0.50 and overall κ for intrarater agreement ranged from 0.59 to 0.77. For both interrater and intrarater agreement, κ coefficients were higher for dogs with normal muscle mass and severe muscle loss and lower for dogs with mild and moderate muscle loss. The MCS was significantly correlated with age (r = −0.62), vertebral epaxial muscle score (VEMS; r = 0.71), forelimb epaxial muscle score (FLEMS; r = 0.58), and BCS (r = 0.73), and VEMS was significantly correlated (r = 0.84) with FLEMS. Cutoff values for identification of mild muscle loss determined by use of VEMS and FLEMS were 1.124 and 1.666, respectively.
CONCLUSIONS AND CLINICAL RELEVANCE
MCS had substantial repeatability and moderate reproducibility for assessment of muscle mass in dogs. Prospective studies of MCS, VEMS, and FLEMS for assessment of muscle mass in dogs are warranted.