The value of advanced imaging in clinical obstetrics

Developments in fetal medicine and invasive surgical procedures have emphasized the importance of having precise diagnosis before delivery. Antenatal diagnosis plays a major role in the management strategy in obstetric practice. Magnetic Resonance imaging (MRI) value in obstetric clinic is evolving rapidly but its use is still restricted in a narrow scope of the practice.

Placental adhesion disorder (PAD) is a severe complication of pregnancy associated with catastrophic postpartum haemorrhage (PPH) if placenta detachment has been attempted at labour. There are three categories of placental invasion, accreta, increta and percreta, at which the severity of the condition is increasing with the depth of invasion. The incidence of PAD is increasing; therefore accurate antenatal diagnosis is fundamental for safe delivery by allowing planning and preparation for delivery by the multidisciplinary team. The diagnostic characteristics of MRI criteria, which are used for evaluation of placental invasion, have not been well evaluated. This thesis sought to further evaluate these criteria and correlate their diagnostic significance with delivery outcome. This study reports a novel value of T2 dark bands as a potential predictor of PAD’s consequent PPH severity and emphasis the value of using combined criteria to improve diagnosis of PAD by MRI.

Congenital chest malformations (CCM) in fetus are the second most commonly referred pathology for fetal MRI after Central nervous system (CNS) lesions. They include a spectrum of malformations and developmental abnormalities, which indicate different treatment options and pregnancy outcome. Therefore, accurate antenatal diagnosis of CCM is essential for parents counselling and management strategy. Recently MRI is used frequently as a complementary diagnostic test to Ultrasound (US). In the second part of this thesis I investigated the value of the fetal MRI in cases with CCM and then an in depth evaluated the significance of MRI in prediction of outcome in cases with congenital diaphragmatic hernia. I found that MRI can detect CCM and differentiate between the different types of CCM better than US. MRI at the early gestation (<25 weeks gestation) can detect fetal mortality better than late MRI (>30 weeks gestation). Using the observed to expected total lung volume is the independent factor to detect fetal mortality and using multiple variable will increase the predictability of MRI for fetal survival. Fetal lung signal intensity may predict pulmonary hypoplasia but have no role to predict the potential ability of the fetus to survive. The important findings emerged here would enable development of a guideline to inform the clinical practice for timing and criteria to use to help predict the likelihood of fetal survival.

Ultrasound still and will continue to be the first line diagnostic modality for evaluation of pregnancy related condition. However, when it fails to provide the required information, MRI acts as an effective alternative or complementary diagnostic technique.