Comparison of gadolinium-enhanced magnetic resonance imaging with ultrasound in evaluation of cesarean scar pregnancy

Aim: The aim of this study was to evaluate the validity of gadolinium-enhanced magnetic resonance imaging (MRI) in diagnosing cesarean scar pregnancy (CSP) and to compare this with ultrasound results. Material and Methods: Forty-two consecutive patients underwent both gadolinium-enhanced MRI and ultrasound to evaluate CSP before treatment from May 2010 to September 2013. The results of both MRI and ultrasound were reviewed and compared to each other with diagnosis of CSP confirmed by pathological findings and clinical outcome. Results: MRI and ultrasound were performed in all 42 patients, with ultrasound performed more than twice in 29 cases. Pathological findings confirmed CSP in all 42 patients, 41 of whom were diagnosed correctly using MRI, with one misdiagnosed as uterine fibroid. Misdiagnosis occurred in seven cases in the first ultrasound, and report was inconclusive in one case. However, correct and definite diagnosis was achieved in repeated ultrasound in seven of the eight cases. The case misdiagnosed as uterine fibroid using MRI was also misdiagnosed as blood clot by ultrasound. The specificity of MRI in diagnosing CSP was 97.6% (41/42) versus 81% (34/42) of the initial ultrasound (P < 0.05). No contrast-agent-related complications occurred in our series. Conclusions: Gadolinium-enhanced MRI is highly specific in the diagnosis of CSP. Ultrasound is relatively less specific when initially performed, but it can be repeated conveniently, with specificity greatly improved. Repeated ultrasound is as specific as MRI in confirming diagnosis of CSP.