Evaluation of Paediatric Complex Congenital Heart Disease on Non-Gated Computed Tomographic Angiography.

Résumé

BACKGROUND: Accurate evaluation of cardiac and extracardiac anomalies in complex congenital heart diseases (CHD) is vital for diagnosis and management. Trans-thoracic echocardiography (TTE) is generally accepted as the primary imaging technique for evaluation of CHD, however, being operator dependent and acoustic window limitations there can be a significant hindrance in better evaluation and depiction of cardiac and extracardiac malformations. CTA has been proved to be competent non-invasive diagnostic modalities in the delineation of both cardiac and extra-cardiac malformations with high accuracy and effectivity. So, it is indispensable as part of an adequate pre-operative assessment algorithm in cases of complex CHD and can’t be replaced by TTE.

OBJECTIVES: To evaluate the role of computed tomographic angiography (CTA) in diagnosis and assessment of cardiovascular and relevant extra-cardiac systemic malformation in cases of complex congenital heart disease and its comparison to transthoracic echocardiography, With the subsequent calculation of average effective radiation dose for each individual case.

PARTICIPANTS: All Cases of complex congenital heart disease had a need for additional CT angiography as deemed by the echocardiographer.
STUDY DESIGN: Prospective observational study.

METHODS: 50 patients with complex congenital heart disease were included in the study, who underwent trans-thoracic echocardiography (TTE) and non-gated CTA over the period of 2yrs. CTA and TTE findings were recorded and compared with the Multi-team discussion, Surgical and Cardiac catheter angiographic findings were taken as the gold standard. Scans were also evaluated for relevant extra-cardiac systemic abnormalities and an effective radiation dose was calculated for each scan.

RESULTS: Fifty patients with a male to female ratio of 29:21 and mean age of 2.7yrs.The sensitivity, specificity, positive predictive value (PPV), negative predictive value (npv) and diagnostic accuracy for diagnosing CHD were 96.1%,100%,100%,99.5% and 99.6% for CTA and 72.4%,98.3%,82.3%,97%, and 84.2% for TTE respectively.we found that CTA has more sensitivity, specificity, npv, PPV, and diagnostic accuracy than TTE not only in intracardiac but also in extracardiac and systemic malformations. The total mean effective radiation dose calculated was 0.85 ± 0.19 MSV.mGy-1.cm-1 and is compared with previous comparable studies. Effective radiation dose was significantly reduced by employing low radiation protocols. The additional findings detected on CTA insignificant proportion of patients had changed the operative course for surgeons.

CONCLUSION: CTA has important clinical value in the diagnosis and management of complex CHD, complementing and extending the findings of TTE. So, it is vital as part of an adequate pre-operative assessment algorithm in cases of complex CHD and can’t be replaced by TTE. However radiation dose remains a limiting factor, this can be overcome to some extent by employing low radiation dose protocols.