Effects of two different anesthetic protocols on 64‐MDCT coronary angiography in dogs

Abstract

Heart rate is a major factor influencing diagnostic image quality in computed tomographic coronary artery angiography (MDCT-CA) with an ideal heart rate of 60–65 beats/minute in humans. Using standardized contrast bolus volume, two different clinically applicable anesthetic protocols were compared for effect on cardiovascular parameters and 64-MDCT-CA quality in ten healthy dogs. The protocol using midazolam/fentanyl (A) was hypothesized to result in adequate reduction of heart rate achieving adequate image quality for MDCT-CA studies and having low impact on blood pressure, where as the protocol utilizing dexmedetomidine (B) was expected to result in reduction of heart rate to the target heart range resulting in excellent image quality while possibly showing undesirable effect on the blood pressure values measured. Heart rate was 80.6 ± 7.5bpm with protocol A and 79.2 ± 14.2bpm with protocol B during image acquisition (P=1). R-R intervals allowing for the best depiction of the individual coronary artery segments were found in the end diastolic period and varied between the 70–95% interval. Diagnostic quality was rated excellent, good and moderate in the majority of the segments evaluated, with higher scores given for more proximal segments and lower for more distal segments respectively. Blur was the most commonly observed artifact and most affected the distal segments. There was no significant difference for the optimal reconstruction interval, diagnostic quality and measured length individual segments or proximal diameter of the coronary arteries between both protocols (P=1). Both anesthetic protocols and the standardized bolus volume allow for diagnostic quality coronary 64-MDCT-CA exams.

Non‐electrocardiographic‐gated computed tomographic angiography can be used to diagnose coronary artery anomalies in Bulldogs with pulmonary valve stenosis

“…In addition, a standardized anesthetic protocol was not used thus variations in aortic flow could have altered coronary artery imaging. However, previous publications evaluating coronary anatomy during CT angiography and aortic flow based on cardiac magnetic resonance imaging, found no significant difference between the two anesthetic protocols that were studied …”

Joint virtual issue on recent advances in veterinary cardiac imaging

“…Although echocardiography is commonly conducted with the patient awake, sedation or general anesthesia is typically necessary to allow for patient restraint during the image acquisition using CT and MRI. The effect of different drug protocols may alter the functional or anatomical variables determined from CT and MRI examinations and has therefore been the subject of several publications . Similarly, cross‐modality correlation and the need for establishment of reference values has prompted several publications, including the first cross‐sectional study published in VRU in 2005 by MacDonald et al using MRI to quality left ventricular mass compared to echocardiography in cats .…”

“…The heart and especially the coronary arteries of our companion animals are much smaller compared to our human counterparts, and heart rates are much higher. These factors indicate the need for high spatial resolution while maintaining rapid scan acquisition; hence, several investigations used advanced multidetector CT units (eg, 64 MDCT) and high‐field MRI (eg, 3T) to establish the feasibility to image these small and fast‐moving structures . Electrocardiographic (ECG) gating is used to match the phase of image acquisition to the phase of the cardiac cycle and is necessary to perform functional evaluation of the heart, using planar and volumetric measurements .…”

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journal/jvim used advanced multidetector CT units (eg, 64 MDCT) and high-field MRI (eg, 3T) to establish the feasibility to image these small and fast-moving structures. [21][22][23] Electrocardiographic (ECG) gating is used to match the phase of image acquisition to the phase of the cardiac cycle and is necessary to perform functional evaluation of the heart, using planar and volumetric measurements. 28 Although ECG gating is routinely used in human patients for evaluation of the coronary arteries, the use of computed tomographic angiography for depiction of the coronary arteries in Bulldogs has been demonstrated without ECG gating, 30 making the technique available to a wider community because not all scanners are able to be equipped with ECG gating and the installation of the necessary softand hardware can be cost prohibitive.Computed tomography in particular has been used for a detailed global assessment of thoracic structures beyond the heart, to determine secondary cardiac effects from thoracic changes, and to evaluate sequelae to cardiac disease and extracardiac vascular anomalies, allowing for accurate diagnosis and treatment planning.

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Joint virtual issue on recent advances in veterinary cardiac imaging

“…The heart and especially the coronary arteries of our companion animals are much smaller compared to our human counterparts, and heart rates are much higher. These factors indicate the need for high spatial resolution while maintaining rapid scan acquisition, hence several investigations used advanced MDCT units (eg, 64 MDCT) and high field MRI (eg, 3T) to establish the feasibility to image these small and fast‐moving structures . Electrocardiographic (ECG) gating is used to match the phase of image acquisition to the phase of the cardiac cycle and is necessary to perform functional evaluation of the heart, using planar and volumetric measurements .…”