US and MRI anatomy of fetal ear

US and MRI anatomy of fetal ear

18 P-42 US and MRI anatomy of fetal ear H. El Mhabrech 1,∗ , A. Messaoud 1 , A. Zrig 2 , H. Zemni 1 , C. Hafsa 1 1 Service d’imagerie Médicale B, Cen...

48KB Sizes 2 Downloads 97 Views

18 P-42

US and MRI anatomy of fetal ear H. El Mhabrech 1,∗ , A. Messaoud 1 , A. Zrig 2 , H. Zemni 1 , C. Hafsa 1 1 Service d’imagerie Médicale B, Centre de maternité et de Néonatologie de Monastir, CHU Fattouma Bourguiba, Monastir, Tunisia 2 Service d’imagerie Médicale A, CHU Fattouma Bourguiba, Monastir, Tunisia ∗ Corresponding author. E-mail address: [email protected] (H. El Mhabrech) Introduction Fetal MRI has progressively become a major tool in prenatal imaging, and its complementary role towards ultrasound (US) is now widely accepted. Ultrasound is still the gold standard for prenatal imaging, but its capacity to rule out temporal bone pathology is limited. In contrast, MRI is capable of high spatial resolution, to study the development of the temporal bone structures during gestation. Indeed, it is possible to fully delineate the cochlea, vestibular apparatus (vestibule and semicircular canals), and the middle ear using MRI with T2-weighted sequences, as early as at gestation week (GW). Objectives Review basic US anatomic views of the evaluation of the fetal ears (external, middle and inner ear). Summarize the MRI sequences allowing good anatomical study. To trace US and MRI anatomy of the fetal ear. Results US anatomy of fetal ear: prenatal sonographic visualization of the fetal middle and inner ear is hampered by acoustic shadowing of the temporal bones. The inner ear: the most important limitation of sonographic fetal cochlear imaging is ossification of the temporal bones, which causes acoustic shadowing. We can see fetal cochlear using coronal head scanning through the mastoid fontanel or squamous suture. Middle ear: ossicle (incus and malleus) are observed only in the second half of pregnancy. They appeared as a bright echo within the upper part of the tympanic ring in. External ear: US can help auricular detection of two ears which is better in 20—24 weeks and can be considered as the best period to detect external ear abnormalities. Prenatal tympanic ring imaging in US is more feasible in the secondtrimester examinations. Tympanic rings appear as distinct, thin, circular structures lying on the infero-lateral surface of the fetal skull. MRI anatomy of fetal ear: — sequences: all fetal cerebral magnetic resonance imaging (MRI) examinations performed at 1.5 Tesla. We review T2-W axial, sagittal and coronal images. The external, middle and inner ears were respectively evaluated. Fetuses presenting with a facial and/or cerebral malformation were excluded; — MRI anatomy: contrary to sonography, the contribution of MRI in the prenatal diagnosis of middle and inner ear abnormalities has been investigated in recent years; — inner ear: the ability to identify the inner structure of the cochlea improved with gestational age, is related to a progressive gain of T2 contrast against the surrounding otic capsule as it ossifies, and not to the cochlear development itself that is supposed to be fully complete. The T2-weighted MRI images showed a high signal intensity of fluid in the membranous labyrinth, which, at 14 weeks, was the first recognizable fetal temporal bone structure; — middle ear: visualization of the middle ear with fetal MRI can be visualized after 25 week. The ossicles are seen as a T2-hypointense area, never with enough detail to discriminate each ossicle. The tympanic cavity is always well-demonstrated on axial and coronal T2-W slices; — external ear: the external ears (EA) are normally only patent after 28 gestation week, after the progressive involution of an ectodermal plug that occludes them until then.

Congrès SFNR 2016 Conclusion MRI represents the most important tool for fetal ear exploration and the knowledge of its anatomy may lead to a better understanding of congenital ear disorders. Disclosure of interest peting interest.

The authors declare that they have no com-

http://dx.doi.org/10.1016/j.neurad.2016.01.089 P-43

Perinatal masses of head and neck: A pictorial review H. El Mhabrech 1,∗ , S. Karma 1 , A. Zrig 2 , K. Ben Ameur 3 , C. Hafsa 1 1 Department of Radiology B, Maternal and Fetal Unit, Fattouma Bourguiba Hospital, Monastir, Tunisia 2 Department of Radiology A, Fattouma Bourguiba Hospital, Monastir, Tunisia 3 Department of Neonatology, Fattouma Bourguiba Hospital, Monastir, Tunisia ∗ Corresponding author. E-mail address: [email protected] (H. El Mhabrech) Objectives To identify typical imaging appearance of lesions of the fetal and neonatal head and neck. To demonstrate particularly of MRI and CT in evaluating the deep cervical structures, characterization of soft tissue lesions and evaluation of enhancement characteristics. Methods and materials Clinical series descriptive study with a retrospective examination of neonates with masses of the neck. US were performed in all patients, CT in 2 cases and Magnetic resonance imaging (MRI) in 9 cases. Results Of our 15 neonates, cervical teratoma was found in 3 cases, cystic lymphangioma in 2 cases, branchial cleft cyst in 1 case, lungual teratoma in 1 case, neuroblastoma in 1 case, extra-axial intracranial archnoid cyst in 3 cases and 4 occipital encephaloceles. Masses can be subdivided into anterior and posterior lesions. The differentiating features that should be noted include the solid or cystic nature of the mass, the thickness of its wall, the vascularity, presence of calcifications and septations or loculations and the laterality. Large masses can have major fetal and perinatal effects due to the compression and distortion of surrounding cervical structures. Conclusion Imaging is often the initial imaging examination for evatuation of perinatal neck and head masses. Ultrasound should serve as the primary initial imaging modality in perinatal head and neck masses. Both magnetic resonance imaging and CT are used for additional evaluation of the lesions. Disclosure of interest peting interest.

The authors declare that they have no com-

http://dx.doi.org/10.1016/j.neurad.2016.01.090 P-44

La sclérose en plaques en 2015 : point de vue du clinicien et du radiologue M. Gaha ∗ , Y. Ben Cheikh , W. Gamaoun , H. Jemni Gharbi , K. Tlili Graiess CHU Sahoul, Sousse, Tunisie ∗ Auteur correspondant. Adresse e-mail : [email protected] (M. Gaha) Cette présentation nous a permis de passer en revue les critères de McDonald de 2010 concernant le diagnostic de la sclérose en plaques (SEP) au stade initial et d’émettre des recommandations facilitant leur application. Nous avons également discuté du protocole IRM optimal à réaliser pour le diagnostic et la surveillance de la SEP. Enfin, nous nous sommes intéressés aux moyens d’améliorer la