Comparison of left and right ventricular stroke volume of dogs calculated on the basis of morphology and blood flow determined by use of cardiac magnetic resonance imaging

Abstract

OBJECTIVE To compare stroke volume (SV) calculated on the basis of cardiac morphology determined by MRI and results of phase-contrast angiography (PCA) of ventricular inflow and outflow in dogs. ANIMALS 10 healthy Beagles. PROCEDURES Cardiac MRI was performed twice on each Beagle. Cine gradient echo sequences of both ventricles in short-axis planes were used for morphological quantification of SVs by assessment of myocardial contours. From the long-axis plane, SVs in 4-chamber and left ventricular 2-chamber views were acquired at end diastole and end systole. For calculation of SV on the basis of blood flow, PCA was performed for cardiac valves. RESULTS Mean ± SD values for SV quantified on the basis of blood flow were similar in all valves (aortic, 17.8 ± 4.1 mL; pulmonary, 17.2 ± 5.4 mL; mitral, 17.2 ± 3.9 mL; and tricuspid, 16.9 ± 5.1 mL). Morphological quantification of SV in the short-axis plane yielded significant differences between left (13.4 ± 2.7 mL) and right (8.6 ± 2.4 mL) sides. Morphological quantification of left ventricular SV in the long-axis plane (15.2 ± 3.3 mL and 20.7 ± 3.8 mL in the 4- and 2-chamber views) yielded variable results, which differed significantly from values for flow-based quantification, except for values for the morphological 4-chamber view and PCA for the atrioventricular valves, for which no significant differences were identified. CONCLUSIONS AND CLINICAL RELEVANCE In contrast to quantification based on blood flow, calculation on the basis of morphology for the short-axis plane significantly underestimated SV, probably because of through-plane motion and complex right ventricular anatomy.

Cardiac MRI in common marmosets revealing age-dependency of cardiac function

“…Under physiological condition, these volumes should of course be similar. Differences in LV-SV and RV-SV, however, have been reported by several MRI studies [27,28]. The reasons for that discrepancy are most likely of technical nature.…”

Recommendations for standardized plane definition in canine cardiac MRI

“…This also facilitates the inclusion of the right ventricular outflow tract into the assessment of right ventricular function. 4,9,12 The evaluation of the flow chart was limited to a small group of healthy dogs of the same breed. Although the method may not be as consistently reproducible when applied to other breeds, the results of this study encourage confidence that the planning principles are transferable, to both other breeds as well as to dogs with cardiovascular disease.…”

“…It would allow for better identification of the pivot point in the subaortic interventricular septum for rotation of the long axis into RVOT. This also facilitates the inclusion of the right ventricular outflow tract into the assessment of right ventricular function 4,9,12 …”

“…The Cantonal Veterinary Office approved the study design (license number 144/2013) and all procedures were conducted in accordance with the Animal Welfare Act of Switzerland. Premedication, general anesthesia, and respiration control were conducted following a previously published protocol 9 …”

“…Second, time‐resolved phase contrast angiography, a cMRI‐technique to quantify flow, depends on perpendicular alignment of the plane to the flow direction 13 . This technique was recently introduced into veterinary medicine for quantification of stroke volume and determination of mitral regurgitant fraction 9,14,15 . Third, for optimal benefit, follow up studies depend on reproducible planes aligned with the cardiac axis.…”