Cross‐sectional area and fat content in dachshund epaxial muscles: an MRI and CT reliability study

Abstract

MRI and CT are frequently used to diagnose spinal diseases in dogs. These modalities have detected epaxial muscle degeneration in dachshunds with intervertebral disc herniation. However, research on the reliability of epaxial muscular measurements is limited in veterinary medicine. The aims of the study were to assess the intrarater and inter-rater reliability of epaxial muscle cross-sectional area (CSA) and fat content measurements on MRI and CT images in dachshunds, and to compare the CSA measurement between the two modalities. MRI and CT images of 10 healthy dachshunds were evaluated. Two blinded observers assessed MRI CSA, MRI fat content, CT CSA and CT muscle attenuation of three thoracolumbar epaxial muscles using OsiriX. The results showed ‘substantial’ to ‘almost perfect’ intrarater reliability (intraclass correlation coefficient (ICC) 0.828–0.998) and inter-rater reliability (ICC 0.685–0.854) for all variables. When individual spinal segments were analysed, the intrarater and inter-rater reliability decreased and the confidence intervals increased. There was positive correlation (r= 0.719–0.841, P=0.001) and high agreement (0.824–0.894) for the measured CSA between MRI and CT. Epaxial muscle CSA and fat content can be reliably measured on MRI and CT, bearing in mind that measurement of certain segments requires adequate training.

Comparison of cross-sectional area and fat infiltration of suboccipital muscles between normal dogs and dogs with atlantoaxial instability

“…To con rm this possibility, future studies are required to compare the histology of SOMs between normal and AAI dogs. However, intramuscular fat is reliably quanti ed using the signal intensity obtained by MRI [13,14,23]. The T1 relaxation time for fat tissue is short, and the signal intensity is high compared with skeletal muscle on the T1-weighted images; therefore, fat appears hyperintense relative to muscle, which is hypointense [23].…”

“…Images were analysed via picture archiving and the use of a communication system (PACSPLUS, Medical Standard, Korea). Measurements followed the methods described in previous reports on dogs and humans [13,14,23,31]. On the transverse T-weighted images, the CSAs of the SOMs (sum of rectus capitis dorsalis, oblique capitis caudalis, and oblique capitis cranialis) were measured bilaterally at C1-2 by manually drawing a region of interest (ROI), tracing the outer margin of the muscles (Fig.…”

“…Human studies have used magnetic resonance imaging (MRI) to investigate the cross-sectional area (CSA) and fat in ltration of the SOMs to design effective management strategies for upper neck problems [10][11][12]. Similar studies have been conducted on the thoracolumbar (TL) epaxial muscles in veterinary medicine [13,14], however, no studies have evaluated the SOMs occupying a large area of this region from the occipital bone to C2 in dogs using MRI.…”

Machine learning model development for quantitative analysis of CT heterogeneity in canine hepatic masses may predict histologic malignancy

“…Muscle was contoured as a 5‐mm 3 sphere in each dog at the level of the T13 dorsal spinous process to correct for noise. Muscle was previously shown to be a reliable reference tissue for signal intensity and cross‐sectional area 19 . When multiple liver tumors were present, the largest tumor biopsied was selected for analysis.…”

Computed tomography radiomic features hold prognostic utility for canine lung tumors: An analytical study

“…The GTV was contracted axially by 0.5 mm to create the final GTV for feature extraction. To correct for noise, a 5 mm 3 region of muscle at the level of the second thoracic vertebrae was used as reference tissue to which all other contour statistics were normalized [ 33 ]. This reference tissue served as the denominator in ratios for comparison of tumor HU data.…”