Assessment of survey radiography as a method for diagnosis of congenital cardiac disease in dogs

Abstract

In order to assess the diagnostic accuracy of survey radiography for canine congenital cardiac anomalies, thoracic radiographs of 57 dogs with congenital cardiac anomalies, 31 normal dogs and 27 dogs with acquired cardiac disease were mixed, and reviewed by two independent observers, who were blinded to any patient information. The congenital anomalies were aortic stenosis (n=25), pulmonic stenosis (n=10), patent ductus arteriosus (n=9), ventricular septal defect (n=8), tricuspid dysplasia (n=3) and mitral dysplasia (n=2). Both observers were moderately accurate at identifying dogs with cardiac disease. Their ability to distinguish dogs with congenital versus acquired cardiac disease was poorer and this assessment was probably influenced by the recognition of patients that were skeletally immature, which biased observers towards a diagnosis of congenital cardiac anomaly. The diagnosis rate for specific congenital anomalies was also poor (the differential list included a correct diagnosis in only 40 and 37 per cent of cases). Radiographic signs of specific cardiac chamber enlargement or pulmonary vascular abnormalities were recognised by both observers in only 20 per cent of instances in which they might be expected. They were, however, recognised more frequently in dogs with anomalies that imposed a volume load on the heart than in dogs with anomalies that induced a pressure load on the organ. It is concluded that survey radiography is an inaccurate method for diagnosis of canine congenital cardiac anomalies because of the difficulty of recognising radiographic signs, which are not present in many cases.

Evaluation of survival rate and prognostic indicators for surgical treatment of left-to-right patent ductus arteriosus in dogs: 52 cases (1995–2003)

“…Different radiographic exposure techniques, differences in cardiac filling, and severe cardiac dilatation may have contributed to that finding. 8,17,26 Dilatation of the right atrium was not observed during echocardiographic examination in our study because it is a subjective evaluation that is not commonly reported. Right ventricular dilatation was observed in 91% of the radiographs obtained in dogs with PDA in 1 study.…”

Measurements of the Pulmonary Vasculature on Thoracic Radiographs in Healthy Dogs Compared to Dogs With Mitral Regurgitation

“…Specific radiographic findings including the change in heart and pulmonary vessels are used to screen cardiac diseases and distinguish left and right heart enlargement, although echocardiography is used as the gold standard for cardiac disease. 4,5 Thoracic radiographs provide more accurate information in predominantly dilative forms of cardiac disease including mitral regurgitation. Enlargement of the pulmonary veins suggests pulmonary venous congestion and left heart failure.…”

Management of incidentally detected heart murmurs in dogs and cats

“…Although these methods may offer useful ancillary information, they cannot provide a definitive etiologic diagnosis of the murmur. For example, in a study 10 to assess the use of survey radiography for diagnosis of congenital cardiac anomalies in dogs, the differential diagnoses included the correct diagnosis for only 21 to 23 of 57 (37% to 40%) dogs with congenital heart disease. For evaluation of young dogs, the diagnostic yield of echocardiography is superior to that of radiographic examination in that it is more likely to provide information needed to identify a congenital heart defect and enables the clinician to better assess disease severity, the occurrence of multiple defects, and the suitability of surgical or medical treatment, and to establish a more accurate prognosis.…”