Placenta, one of the least understood human organs, is external to fetal body with genetic characteristics identical to the fetus. Placenta is made up of its parenchyma, membranes, and umbilical cord (UC). It involved in the transfer blood gases and nutrients, act as immune barrier, secrete hormones and other substances. Ultrasound, Doppler, and MRI are used to evaluate placental configuration and predict adverse outcomes. MR adds value to fetal and placental sonographic evaluation thanks to its wide field of view and high tissue contrast. Single shot fast spin echo (SSFSE), balanced steady state and T1-W, occasionally DWI, are the most used sequences. We present the spectrum of morphologies and pathologies of the placenta and UC on ultrasound and MRI. Placental location and shape: Placental location is based on its relationship with the uterus and cervix. The placenta tends to migrate toward the fundus throughout pregnancy. Placental thickness ranges from 2-4 cm. It can be a single structure, bilobed or have an accessory lobe. Variations include circumvallate and placenta membranacea. Placental signal: Normal parenchyma is intermediate to hyperintense on fluid sensitive images, more homogenous in the second trimester and progressively becoming lobulated and septated. Increased number and size of cotyledons make the placenta more heterogenous. Placental hemorrhage: Blood pooling and hemorrhage are another cause of placental heterogeneity. Placental-myometrial Interface: Best seen on steady state, displaying a trilaminar appearance. Chorionicity: Chorionicity and amnionicity are determined on the first trimester ultrasound. MRI offers a larger field of view for evaluation of the membranes’ attachment and UC in the second and third trimesters. UC insertion: UC inserted to the center of the placenta. Eccentric insertions, and velamentous insertions can be identified on MRI. UC structure: The UC contains two umbilical arteries, a single umbilical vein, allantois duct and Wharton's jelly and is enclosed within the outer layer of amnion. UC varix: This refers to the dilation of the fetal umbilical veins as it runs through the fetal abdomen. UC cysts: Uncommon, differential diagnosis includes pseudocysts, omphalomesenteric duct cysts, vascular disorders, abdominal wall defects, bladder exstrophy and urachal anomalies. Placental Tumors. Placental tumors are categorized in trophoblastic and non-trophoblastic. The latter include chorioangiomas, teratomas, and hemangiomas. Read More

Meeting name: SPR 2024 Annual Meeting & Postgraduate Course , 2024

Authors: Sarrami Amir Hossein, Rubesova Erika

Keywords: Placenta, Fetal MRI, Ultrasound

Medical Imaging has a crucial role in the diagnosis and management of pediatric cancer patients by providing information about tumor location and quantitative measures of tumor size and metabolic activity at baseline as well as during and after therapy. The standard imaging plan for staging and re-staging of pediatric malignancies includes a high-resolution MRI or CT scan of the local tumor and whole body staging for the detection of metastases on CT, MRI and/or PET scans. Children with lymphomas, sarcomas, germ cell tumors and a few other tumor types are referred to whole body 18F-FDG PET scanning, either coupled with CT or MRI. Artificial intelligence (AI) algorithms can facilitate staging and re-staging of cancers in children by providing 1) rapid detection and delineation of tumoral lesions, 2) automated measurements of tumoral size and metabolic activity, 3) relating tumor measurements to internal standard such as liver and blood pool, 4) assigning a score according to tumor-specific staging systems. Detecting tumors on a whole-body scan is a challenging task, especially in children whose organs undergo changes in size and composition with increasing age. Moreover, the tumors in children can arise from almost anywhere in the body, from head to toe. With successful applications on object detection, AI methods are promising for automatic tumor detection from whole-body scans as well. In this tutorial, we will introduce a few popular AI methods for such purpose. These methods include U-Net, Vision Transformers (ViT), and the hybrid of the above methods such as O-Net Transformer or TransUNet. Read More

Meeting name: SPR 2023 Annual Meeting & Postgraduate Course , 2023

Authors: Sarrami Amir Hossein, Wang Hongzhi, Baratto Lucia, Syeda-mahmood Tanveer, Daldrup-link Heike

Keywords: Hybrid Imaging, Artificial Intelligence, Cancer