Fetal neurosurgery.

Among fetal surgical procedures, neurosurgery stands out due to the number of cases and the possibility of developing new procedures that can be performed in the fetal period. To perform fetal neurosurgical procedures, there is a need for specialized centers that have experts in the diagnosis of fetal pathologies and a highly complex obstetrics service with specialized maternal-fetal teams associated with a pediatric neurosurgery center with expertise in the diverse pathologies of the fetus and the central nervous system that offers multidisciplinary follow-up during postnatal life. Services that do not have these characteristics should refer their patients to these centers to obtain better treatment results. It is essential that the fetal neurosurgical procedure be performed by a pediatric neurosurgeon with extensive experience, as he will be responsible for monitoring these patients in the postnatal period and for several years. The objective of this manuscript is to demonstrate the diagnostic and treatment possibilities, in the fetal period, of some neurosurgical diseases such as hydrocephalus, tumors, occipital encephalocele, and myelomeningocele.

The Facial Nerve: Anatomy and Pathology.

The facial nerve is the seventh cranial nerve and consists of motor, parasympathetic and sensory branches, which arise from the brainstem through 3 different nuclei (1). After leaving the brainstem, the facial nerve divides into 5 intracranial segments (cisternal, canalicular, labyrinthine, tympanic, and mastoid) and continues as the intraparotid extracranial segment (2). A wide variety of pathologies, including congenital abnormalities, traumatic disorders, infectious and inflammatory disease, and neoplastic conditions, can affect the facial nerve along its pathway and lead to ​​weakness or paralysis of the facial musculature (1,2). The knowledge of its complex anatomical pathway is essential to clinical and imaging evaluation to establish if the cause of the facial dysfunction is a central nervous system process or a peripheral disease. Both computed tomography (CT) and magnetic resonance imaging (MRI) are the modalities of choice for facial nerve assessment, each of them providing complementary information in this evaluation (1).

The Cecum Revisited: A Multimodality Imaging Case-based Review of Common and Uncommon Cecal Diseases.

A wide range of conditions involving the cecum may be found in patients undergoing imaging work-up for conditions as various as right lower pain, diarrhea, fever, and weight loss. The cecum may be the only area of involvement by a particular disease. However, it may also be affected by a more diffuse process of the gastrointestinal tract or even as part of systemic diseases. Imaging provides an excellent evaluation of the cecal region and its surrounding planes, with an impactful clinical application in multiple scenarios. While typical features in many situations allow establishing a confident diagnosis, there are also challenging entities with overlapping features, making it critical for the radiologist awareness of the whole gamut of these conditions, as well as the ability to correlate imaging findings with other clinical data. Additional challenges to the imaging evaluation include anatomical variations of the cecal position and the absence of proper colonic distention in some cases. This article aims to revisit the spectrum of cross-sectional imaging features of common and uncommon pathologies involving the cecum, ranging from inflammatory and infectious to vascular and neoplastic ones.

The Optic Nerve: Anatomy and Pathology.

The optic nerve is the second cranial nerve but is not a true cranial nerve. Instead, it's an extension of the brain parenchyma. The optic nerve transmits electrical impulses from the retina to the brain, which will be processed in visual information. Often, the clinical definition of a lesion in the optic nerves is not clear, and magnetic resonance imaging (MRI) plays a crucial role. In addition, the optic nerves can be affected by several diseases, such as congenital malformations, inflammatory, vascular, and neoplastic diseases. This article aims to review the optic nerve anatomy, discuss the best MRI techniques to evaluate each nerve segment, and demonstrate the imaging aspect of the diseases that most commonly affect it.

The Olfactory Nerve: Anatomy and Pathology.

The human sense of smell is the unique sense through which the olfactory system can identify aromatic molecules within the air and provide a taste sensation. Still, also it plays an essential role in several other functions, warning about environmental safety and even impacts our emotional lives. Recently, olfactory impairment has become an issue of interest due to the COVID-19 pandemic. The dysfunction may vary from only reduced smell detection (hyposmia) to complete loss of it (anosmia) but also includes changes in the normal perception of odors (parosmia). Computed tomography and magnetic imaging resonance are the modalities of choice to evaluate the olfactory pathways. Computed tomography is the initial imaging modality for olfactory disturbances, allowing recognition of sinonasal pathologies, inflammatory processes, or bone-related tumors. Magnetic imaging resonance with dedicated protocols for olfactory disorders enables a detailed assessment of the sinonasal compartment and the anterior cranial fossa. Provides a better depiction of olfactory bulb volume, morphology and signal intensity, as well the status of signal intensity of the central olfactory projection areas. Several diseases can affect the olfactory nerve, such as congenital disorders, trauma, inflammatory or infectious diseases, neoplasms, and even post-operative involvement. This article aims to review the normal anatomy of the olfactory nerve pathway and highlight the spectrum of conditions that most commonly affect it.

The Trigeminal Nerve: Anatomy and Pathology.

The trigeminal nerve is the fifth cranial nerve and is a sensory-motor nerve that provides the innervation to the face with its three roots. The trigeminal nerve can be affected by several diseases, such as vascular conflict, congenital malformation, inflammatory or neoplastic diseases. Magnetic Resonance Imaging plays a crucial role in its evaluation. This article aims to review the trigeminal nerve anatomy, discuss the best magnetic resonance imaging techniques to evaluate each nerve segment, and demonstrate the imaging aspect of the diseases that most commonly affect it.

The Abducens Nerve: Anatomy and Pathology.

The abducens, or the sixth cranial nerve, is purely motor and runs a long course from the brainstem to the lateral rectus. Travels with the inferior petrosal sinus through the Dorello's canal before entering the cavernous sinus. Based on the location of an abnormality, other neurologic structures may be involved with the disturbs related to this nerve. This article aims to review the abducens nerve anatomy and demonstrates the imaging aspect of the diseases that most commonly affect it.