Imaging of congenital spine and spinal cord malformations

Cell Transplantation for Repair of the Spinal Cord and Prospects for Generating Region-Specific Exogenic Neuronal Cells

Spinal cord injury (SCI) is associated with currently irreversible consequences in several functional components of the central nervous system. Despite the severity of injury, there remains no approved treatment to restore function. However, with a growing number of preclinical studies and clinical trials, cell transplantation has gained significant potential as a treatment for SCI. Researchers have identified several cell types as potential candidates for transplantation. To optimize successful functional outcomes after transplantation, one key factor concerns generating neuronal cells with regional and subtype specificity, thus calling on the developmental transcriptome patterning of spinal cord cells. A potential source of spinal cord cells for transplantation is the generation of exogenic neuronal progenitor cells via the emerging technologies of gene editing and blastocyst complementation. This review highlights the use of cell transplantation to treat SCI in the context of relevant developmental gene expression patterns useful for producing regionally specific exogenic spinal cells via in vitro differentiation and blastocyst complementation.

Ischemic myelomalacia and closed spinal dysraphism in multiple finishing swine

Ischemic myelomalacia secondary to fibrocartilaginous emboli (FCE) is an idiopathic disease in humans and animals. On the other hand, congenital spinal cord malformations result from neural tube defects in fetal development (ie, spinal dysraphism), with structural anomalies referred to collectively as myelodysplasia. Spinal dysraphisms are frequently accompanied by skin and vertebral abnormalities because of the embryogenic relationship. In this observational case study, we report the pathologic findings of 13, 18- to 24-weeks-old pigs from a large conventional operation that presented with acute paraparesis. Ischemic myelomalacia secondary to FCE was observed in 5 of 13 examined pigs. Congenital spinal cord malformations located between the caudal thoracic and sacral spinal cord were identified in 7 pigs, with structural abnormalities that ranged from diplomyelia/split cord malformation to segmental spinal dysgenesis (myelodysplasia) to caudal agenesis. Concurrent myelomalacia and congenital spinal cord malformations in the same or different sites were noted in 2 pigs. No spinal lesion was observed in 3 pigs. Although gross vertebral abnormalities were not observed herein, intervertebral instability due to minor defects in the articular facets, as well as other unidentified factors, is suspected to contribute high incidence of FCE. It is likely that these congenital malformations were previously underdiagnosed or are possibly new conditions associated with continuous inbreeding and genetic improvement in the modern swine industry.

A comparison of the accuracy of fetal magnetic resonance imaging and ultrasonography for the diagnosis of fetal congenital malformations of the spine and spinal cord

PURPOSE

To determine the diagnostic value of fetal magnetic resonance imaging (MRI) for congenital spine/spinal cord malformations.

METHODS

This single-center retrospective study included 120 cases of fetal spine/spinal cord abnormalities detected using fetal ultrasonography (US) and further examined by fetal MRI between 2016 and 2020. Cases were divided into three groups (congenital spine, spinal cord, and spine + spinal cord malformations) based on US assessment. We analyzed the accuracy of fetal US and MRI relative to postnatal imaging.

RESULTS

The diagnostic accuracy of fetal MRI for fetal spinal cord, spine, and spine + spinal cord malformations was 86.2% (25/29), 89.4% (42/47), and 86.3% (38/44), respectively, and the corresponding rates for fetal US were 51.7% (15/29), 87.2% (41/47), and 68.2% (30/44). The diagnostic accuracy did not differ between fetal MRI and US for congenital spine malformations (P > 0.05); for congenital spinal cord malformations and congenital spine+spinal cord malformations, the diagnostic accuracy was significantly higher for fetal MRI than for fetal US (P < 0.05).

CONCLUSIONS

Fetal MRI is effective in the assessment of congenital spine/spinal cord malformations. It can yield information that supplements US findings, especially for congenital spinal cord malformations, and can improve the accuracy of fetal diagnosis. This article is protected by copyright. All rights reserved.

The value of magnetic resonance imaging and computed tomography in the study of spinal disorders

Computed tomography (CT) and magnetic resonance imaging (MRI) have replaced conventional radiography in the study of many spinal conditions, it is essential to know when these techniques are indicated instead of or as complementary tests to radiography, which findings can be expected in different clinical settings, and their significance in the diagnosis of different spinal conditions. Proper use of CT and MRI in spinal disorders may facilitate diagnosis and management of spinal conditions. An adequate clinical approach, a good understanding of the pathological manifestations demonstrated by these imaging techniques and a comprehensive report based on a universally accepted nomenclature represent the indispensable tools to improve the diagnostic approach and the decision-making process in patients with spinal pain. Several guidelines are available to assist clinicians in ordering appropriate imaging techniques to achieve an accurate diagnosis and to ensure appropriate medical care that meets the efficacy and safety needs of patients. This article reviews the clinical indications of CT and MRI in different pathologic conditions affecting the spine, including congenital, traumatic, degenerative, inflammatory, infectious and tumor disorders, as well as their main imaging features. It is intended to be a pictorial guide to clinicians involved in the diagnosis and treatment of spinal disorders.

Diffusion Kurtosis Imaging of Neonatal Spinal Cord in Clinical Routine

Diffusion kurtosis imaging (DKI) has undisputed advantages over the more classical diffusion magnetic resonance imaging (dMRI) as witnessed by the fast-increasing number of clinical applications and software packages widely adopted in brain imaging. However, in the neonatal setting, DKI is still largely underutilized, in particular in spinal cord (SC) imaging, because of its inherently demanding technological requirements. Due to its extreme sensitivity to non-Gaussian diffusion, DKI proves particularly suitable for detecting complex, subtle, fast microstructural changes occurring in this area at this early and critical stage of development, which are not identifiable with only DTI. Given the multiplicity of congenital anomalies of the spinal canal, their crucial effect on later developmental outcome, and the close interconnection between the SC region and the brain above, managing to apply such a method to the neonatal cohort becomes of utmost importance. This study will (i) mention current methodological challenges associated with the application of advanced dMRI methods, like DKI, in early infancy, (ii) illustrate the first semi-automated pipeline built on Spinal Cord Toolbox for handling the DKI data of neonatal SC, from acquisition setting to estimation of diffusion measures, through accurate adjustment of processing algorithms customized for adult SC, and (iii) present results of its application in a pilot clinical case study. With the proposed pipeline, we preliminarily show that DKI is more sensitive than DTI-related measures to alterations caused by brain white matter injuries in the underlying cervical SC.

Spinal dysraphism illustrated; Embroyology revisited

Spinal cord development occurs through three consecutive periods of gastrulation, primary nerulation and secondary neurulation. Aberration in these stages causes abnormalities of the spine and spinal cord, collectively referred as spinal dysraphism. They can be broadly classified as anomalies of gastrulation (disorders of notochord formation and of integration); anomalies of primary neurulation (premature dysjunction and nondysjunction); combined anomalies of gastrulation and primary neurulation and anomalies of secondary neurulation. Correlation with clinical and embryological data and common imaging findings provides an organized approach in their diagnosis.

Unveiling the tale of the tail: an illustration of spinal dysraphisms

Spinal dysraphism is an umbrella term describing herniation of meninges or neural elements through defective neural arch. They can be broadly categorized into open and closed types. MRI is the investigation of choice to study neural abnormalities and to assess the severity of hydrocephalus and Chiari malformation. Knowledge of the embryology of these disorders is valuable in correctly identifying the type of dysraphism. The aim of surgery is untethering and dural reconstruction. Accurate depiction of the abnormal anatomy in cases of spinal dysraphism is of utmost importance for surgical management of these patients. MRI makes this possible due to its excellent soft tissue contrast resolution and multiplanar capability, allowing the radiologist to evaluate the intricate details in small pediatric spinal structures. Imaging enlightens the surgeons about the status of spinal cord and other associated abnormalities and helps detect re-tethering in operated cases. Besides, antenatal surgery to repair myelomeningoceles has made detection of open dysraphisms on fetal MRI and antenatal ultrasound critical. The purpose of this review is to describe the development of spine, illustrate the myriad imaging features of open and closed spinal dysraphisms, and enlist the reporting points the operating surgeon seeks from the radiologist.

Imaging spectrum of spinal dysraphism on magnetic resonance: A pictorial review

Congenital malformations of spine and spinal cord are collectively termed as spinal dysraphism. It includes a heterogeneous group of anomalies which result from faulty closure of midline structures during development. Magnetic resonance imaging (MRI) is now considered the imaging modality of choice for diagnosing these conditions. The purpose of this article is to review the normal development of spinal cord and spine and reviewing the MRI features of spinal dysraphism. Although imaging of spinal dysraphism is complicated, a systematic approach and correlation between neuro-radiological, clinical and developmental data helps in making the correct diagnosis.

Congenital malformations of the brain and spine

In this chapter we briefly address the most common congenital brain and spinal anomalies as well as their most salient imaging, especially magnetic resonance, findings. Some of them, such as Chiari II, and open spinal defects, have become relatively rare due to their detection in utero and repair of the spinal malformation. Regardless of the type of brain anomaly, the most common clinical symptoms are mental retardation, hydrocephalus, and seizure; the latter two may need to be surgically and medically addressed. The most commonly found spinal congenital anomalies include the filum terminale lipoma which is generally asymptomatic and incidental and the caudal regression syndrome for which no primary treatment exists. Any spinal congenital anomaly may present in adulthood as a consequence of spinal cord tethering and/or development of syringomyelia.

Emergencies in pediatric surgery

Primary care physicians are often required to initially manage the children with surgical emergencies. Many neonates with congenital malformations delivered without supervision may also be managed initially by the family physicians. The role of the primary care physician in such cases should be to diagnose the condition correctly, provide immediate care and then refer the newborn or child to higher centre for appropriate management.

Genetic evidence in planar cell polarity signaling pathway in human neural tube defects

Neural tube defects (NTDs) are a group of birth anomalies having a profound physical, emotional, and financial effects on families and communities. Their etiology is complex, involving environmental and genetic factors that interact to modulate the incidence and severity of the developing phenotype. The planar cell polarity (PCP) pathway controls the process of convergent extension (CE) during gastrulation and neural tube closure and has been implicated in the pathogenesis of NTDs in animal models and human cohorts. This review summarizes the cumulative results of recent studies on PCP signaling pathway and human NTDs. These results demonstrate that PCP gene alterations contribute to the etiology of human NTDs.

Genome-wide association mapping in dogs enables identification of the homeobox gene, NKX2-8, as a genetic component of neural tube defects in humans

Neural tube defects (NTDs) is a general term for central nervous system malformations secondary to a failure of closure or development of the neural tube. The resulting pathologies may involve the brain, spinal cord and/or vertebral column, in addition to associated structures such as soft tissue or skin. The condition is reported among the more common birth defects in humans, leading to significant infant morbidity and mortality. The etiology remains poorly understood but genetic, nutritional, environmental factors, or a combination of these, are known to play a role in the development of NTDs. The variable conditions associated with NTDs occur naturally in dogs, and have been previously reported in the Weimaraner breed. Taking advantage of the strong linkage-disequilibrium within dog breeds we performed genome-wide association analysis and mapped a genomic region for spinal dysraphism, a presumed NTD, using 4 affected and 96 unaffected Weimaraners. The associated region on canine chromosome 8 (pgenome  =3.0 × 10(-5)), after 100,000 permutations, encodes 18 genes, including NKX2-8, a homeobox gene which is expressed in the developing neural tube. Sequencing NKX2-8 in affected Weimaraners revealed a G to AA frameshift mutation within exon 2 of the gene, resulting in a premature stop codon that is predicted to produce a truncated protein. The exons of NKX2-8 were sequenced in human patients with spina bifida and rare variants (rs61755040 and rs10135525) were found to be significantly over-represented (p=0.036). This is the first documentation of a potential role for NKX2-8 in the etiology of NTDs, made possible by investigating the molecular basis of naturally occurring mutations in dogs.