Clinical utility of a new protocol of cardiac computed tomography in dogs

Our plain-English summary of Clinical utility of a new protocol of cardiac computed tomography in dogs, by J. Kim, S. Lee, J. Hwang, et al (Veterinary Medicine and Science, 2023).

The study

• Authors: J. Kim, S. Lee, J. Hwang, J. Yoon
• Journal: Veterinary Medicine and Science
• Published: 2023;9(2):645-652
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: The characteristics of non-electrocardiography- and electrocardiography-gated multidetector computed tomography have not been extensively studied in veterinary clinics but it can be useful for cardiac imaging. This study aimed to ascertain the differences between non-electrocardiography and electrocardiography gating methods and to establish their clinical utility based on patient history.

Methods: Six client-owned dogs (two with patent ductus arteriosus, two with heart base tumour, one with pericardial mesothelioma, and one with normal health) were included in this study. All the dogs were examined using a non-electrocardiography-gated scan, followed by a retrospective electrocardiography-gated scan. Images were reviewed to determine the optimal scan timing and R-R interval in non-electrocardiography- and electrocardiography-gated images, respectively, for detailed coronary artery imaging, diagnostic quality of the best coronary artery visualisation in non-electrocardiography- and electrocardiography-gated images through visual assessment of the main coronary artery branches, and branching patterns of the left coronary artery. Further, we compared the size and margin demarcation of the heart or pericardial lesions in non-electrocardiography- and electrocardiography-gated images obtained from patients with heart or pericardial tumours.

Results: The optimal scan timing and R-R interval were the second-scan timing and end-diastole (70%-90%), respectively. Second-scan non-electrocardiography-gated images allowed coronary artery evaluation, indicating high-grade quality in visual assessment, except for the septal branch. Electrocardiography-gated images, but not non-ECG-gated images, clearly revealed pericardial nodules in two dogs.

Clinical Significance: Our findings suggest the respective clinical utilities of non-electrocardiography- or electrocardiography-gated imaging using high-slice cardiac computed tomography based on patient history.

© 2022 The Authors. Veterinary Medicine and Science published by John Wiley & Sons Ltd.

In plain English

This retrospective, observational veterinary study looked at six client-owned dogs scanned with 160-multislice CT angiography between 2020 and 2021. It does not concern asbestos. Two dogs had patent ductus arteriosus, two had heart base tumours, one had pericardial mesothelioma confirmed by tissue examination, and one had normal check-up findings. Each dog had a scan not timed to the heartbeat (non-ECG-gated) followed by a scan timed to the heartbeat (ECG-gated). For viewing the coronary arteries, the best timing was the second non-ECG-gated scan and, for ECG-gated scans, the 70% to 90% part of the heartbeat cycle. Non-ECG-gated images showed most coronary artery branches at good to excellent quality. The septal branch was poor to mild in three dogs, and the right coronary artery in one. ECG-gated images scored higher, but not statistically significantly. Only ECG-gated images clearly showed small pericardial nodules, in the mesothelioma dog and one heart base tumour dog. The authors concluded that non-ECG-gated scanning is a viable way to shorten anaesthesia when coronary arteries need evaluating, and that ECG-gated scanning suits suspected heart or pericardial tumours. They noted the small sample size.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective, observational study of medical records (veterinary imaging comparison)
• Who was studied: Six client-owned dogs scanned at an animal medical centre from 2020 to 2021 (South Korea). Two had patent ductus arteriosus, two had heart base tumours, one had pericardial mesothelioma and one had normal findings. Mean age was 63.17 ± 46.46 months and mean body weight was 7.1 ± 4.13 kg.
• Exposure: No asbestos or other exposure was studied. The study compared two imaging methods in the same dogs: a non-ECG-gated scan followed by a retrospective ECG-gated scan, both on an 80-row, 160-multislice CT system.
• Main results:
  • In all dogs, the second non-ECG-gated scan showed maximal contrast in the proximal ascending aorta. This was used to set the ECG-gated scan delay of approximately 15 s.
  • In ECG-gated images, the best interval for coronary artery evaluation was the end-diastolic phase, at 70% to 90% of the R-R interval.
  • Second non-ECG-gated scan images gave good to excellent visualisation of most coronary artery branches. However, the septal branch was low-grade (poor to mild) in three dogs and the right coronary artery in one dog.
  • Compared with a virtual reference group assigned grade 0, the non-ECG group had significantly higher imaging quality in all coronary artery branches except the septal branch. The ECG group was significantly higher in all branches.
  • ECG-gated images showed higher imaging quality than non-ECG-gated images, but the difference was not statistically significant.
  • Left coronary artery branching patterns were type 1 in two dogs, type 2 in one, type 5 in one and type 6 in two. None of the dogs had aberrant coronary arteries.
  • In Case 1 (heart base tumour) and Case 4 (pericardial mesothelioma), small pericardial nodules were clearly seen on ECG-gated images but not clearly identified on non-ECG-gated images.
  • In Case 1, the heart base tumour measured 12.62 × 8.86 mm on non-ECG-gated images and 14.93 × 10.16 mm on ECG-gated images. In Case 5, there was no difference in mass size between the methods.
  • Three-dimensional volume rendering could not be done in the dog with pericardial mesothelioma because of a large amount of pericardial effusion.
• The authors' conclusion: The authors concluded that non-ECG-gated high-slice CT should be considered a viable option for reducing anaesthesia time when coronary artery evaluation is needed. They also concluded that ECG-gated CT is appropriate for patients with suspected intra-cardiac or pericardial tumours.
• Limitations the authors state:
  • The sample size was small.
  • The two dogs with heart base masses (Cases 1 and 5) had no histopathological examination because the owners did not consent to biopsy, so the nature of the masses was not determined.
  • Dogs with fast or irregular heart rates still need to be evaluated with non-ECG-gated high-slice CT.

Topics

Medical terms in this study, explained in our Lexicon: Pericardial Mesothelioma, Pericardial.

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