Radiomorphometric studies of the thorax in Nigerian indigenous dog: Novel thoracic measurements

Abstract

Evaluation of the heart in terms of its silhouette size and shape and the morphometry of other thoracic organs cannot be ignored diagnostically in small animal practice when history and or results of general examination of a patient reveal clinical signs of cardiothoracic diseases. However, there is a paucity of published work on the radiologic appraisal of cardiac and thoracic dimensions in the Nigerian indigenous dog. The research aimed to establish new reference indices for improved diagnosis of cardiothoracic pathologies in the Nigerian indigenous dog. A total of 120 thoracic radiographs of thirty healthy Nigerian indigenous dogs, comprising right lateral, left lateral, dorsoventral and ventrodorsal projections, were obtained and evaluated. Biometric parameters were taken of each research radiographs, recorded, and used to generate cardiothoracic measurement indices for the Nigerian indigenous dog. In the dorsoventral versus ventrodorsal projections, ratios established and described as means plus or minus standard errors of means were as follows: cardiac width/cardiac length ratio 0.75±0.01/0.73±0.01; cardiac length/thoracic diameter 0.64±0.01/0.70±0.01; and heart width/costocostal distance ratio 0.58±0.01/0.60±0.01, respectively. The mean results obtained in the right lateral versus left lateral radiographs were: postcava-to-long axis ratio 0.14±0.00/0.15±0.00; cardiac axes ratio 0.75±0.01/0.81±0.01; cavocardiac ratio 0.19±0.01/0.19±0.01; aorticocardiac ratio 0.22±0.0/0.21±0.00; short axis/sternovertebral distance 0.63±0.01/0.63±0.01; and aortic diameter/long axis ratio 0.17±0.00/0.17±0.00, respectively. The cardiac axes ratio and aorticocardiac ratio showed a positive and significant (p≤0.05) relationship with the cardiac short axis in the lateral projections. The indices established in this study are reproducible and easy to use, allowing objective thoracic assessment. All the results are efficient and generated in the present investigation, probably, for the first time in veterinary radiology. The clinical relevance of this research is related to the management of cardiothoracic anomalies.

Radiologic indices of cardiac mensuration in the African grasscutter (Thryonomys swinderianus)

“…The values of CAR in the juvenile and adult African grasscutter from the present study did not differ significantly, neither was there any significant difference between the CAR of opposite projections in any of the two age groups. In their study, Ukaha et al (2002) also observed that CAR between puppies and adult Nigerian indigenous dogs did not differ significantly. The authors also observed that CAR of opposite projections did not differ significantly in both the puppies and adult Nigerian indigenous dog.…”

“…Dennis et al (2010) opined that increased diagnostic yield and accuracy of cardio-thoracic radiographic appraisals is achieved by the use of these four thoracic radiographic projections. Some of the radiographic indices that depict the size of cardiac silhouette include the cardio-clavicular ratio (Gardner et al, 2007), cardiac long axis-thoracic height ratio (Diniz et al, 2013), vertebral heart score (VHS) (Luciani et al, 2019), vertebral left atrial size (Puccinelli et al, 2021), cardio-thoracic ratio (CTR) (Sak and Pazvant, 2021), aorticocardiac ratio (Ukaha et al, 2002) and cardiac axis ratio (CAR) (Ukaha et al, 2002). However, CTR, VHS and CAR are of interest in the present study.…”

“…Previously, clinicians read thoracic radiographs based on subjective or personal opinion of structures assessed, oftentimes resulting in high error margin. The advent of measurement methods in radio-diagnostics has proved more sensitive and accurate, eliminating the high error margin associated with subjective interpretation (Ukaha et al, 2002;Hansson, 2004). These radiographic measurements generate indices that depict the size of the cardiac silhouette.…”

“…This suggests that both indices are valid methods that can be used in the discrimination between normal heart size and cardiomegaly or microcardia in these species. The CAR, an index that measures the ratio of the short axis to the long axis of the heart on a lateral view, has been established for the male and female as well as for puppy and adult Nigerian indigenous dog (Ukaha et al, 2002). It is not influenced by respiratory phases, unlike CTR, thus, must not be taken at full inspiration (Ukaha et al, 2002).…”

Right versus left lateral recumbent radiographs for assessment of the cardiac silhouette in dogs

“…Paper 8 : Radiomorphometric studies of the thorax in Nigerian indigenous dogs: novel thoracic measurements 8 …”