Accuracy of Two-dimensional Ultrasound and Magnetic Resonance Imaging in Diagnosis of Foetal Congenital Anomalies in a Tertiary Care Hospital- A Cross-sectional Study

Abstract

Introduction: Ultrasound screening for foetus congenital malformations is the mainstay in diagnosis and is commonly performed at 19-22 weeks gestation. Magnetic Resonance Imaging (MRI) is known as a problem solving tool which is used for answering a specific question. Both ultrasound and foetus MRI are highly sensitive and specific in diagnosis of congenital anomalies of the foetus with high agreement between both modalities. Aim: To determine the accuracy of Ultrasound Sonography (USG) and High Field 3 tesla MRI in diagnosis of different types of foetal Central Nervous System (CNS) and non CNS congenital abnormalities. Materials and Methods: A cross-sectional study was conducted in the Department of Radiodiagnosis at Agartala Government Medical College and GB Pant Hospital from June 2017 to May 2019. A total of 65 cases with ultrasound diagnosis of foetus abnormalities were examined by 3 Tesla MRI. MRI were performed within 15 days after USG detected anomalies. Statistical analysis was done using Chi-square test. Results: In cases with foetus anomalies high field MRI provided detailed findings leading to a more refined diagnosis. CNS anomalies were more as compared to other anomalies. Some of the antenatal findings were confirmed in some cases following termination of pregnancy and some were by postnatal examination. Among them chest anomalies was least common i.e., 1.5%. sensitivity of MRI was 88.13%, specificity was 66.66%, Positive Pressure Ventilation (PPV) was 96.29%, Negative Predictive Value (NPV) was 36.36% and USG sensitivity was 82.43%, specificity and 77.77%, PPV was 95.83%and NPV was 41.17%. Conclusion: High field MRI should be used as a second line of investigation in patients with foetus abnormalities diagnosed by ultrasound for confirmation of diagnosis and selecting the treatment protocol. In cases of fatal abnormalities, a confirmed diagnosis made before 20 weeks of pregnancy may help by terminating the pregnancy.