Vascular Myelopathies.

There are many vascular disorders that can affect the spinal cord, and their prevalence and etiology are highly influenced by age, sex, and risk factors. This article reviews the embryology and anatomy of the spinal cord, as well as several vascular conditions, describing their clinical and imaging presentation, emphasizing the different imaging modalities' contributions to increasing specificity and better defining the most appropriate therapy strategy for improving the patient's prognosis.

Imaging Aspects of Toxic and Metabolic Myelopathies.

Metabolic and toxic myelopathies usually occurs due to several different causes. Metabolic myelopathy usually occurs due to deficiency of a nutrient, such as vitamin B12. Toxic myelopathy occurs secondary to the exposure to an external toxic agent. Although they may have a difficult diagnosis, determination of the specific cause of myelopathy is of utmost importance, because many causes are amenable to treatment. Although they have many clinical, electrophysiologic, and neuropathologic similarities, imaging may aid in the suspicion of toxic or metabolic myelopathy. The aim of this article, is to review the imaging features of the main toxic and metabolic myelopathies.

"Bunch of acai berries sign": a new radiological sign in patients with CNS involvement in Chagas disease.

Chagas disease is an infection caused by Trypanosoma cruzi, a parasite endemic in Latin America. Acute involvement of the CNS by Chagas has been considered rare, but presumed reactivation of chronic disease in immunosuppressed patients has been the subject of recent reports. Our objective is to describe the clinical and imaging characteristics of four patients with Chagas disease and CNS involvement, and the patients had to have available MRI and a diagnosis confirmed by biopsy. The imaging findings were similar, highlighting the presence of focal cerebral lesions with hypointensity on T2-WI, and these lesions assume a "bunch of acai berries appearance", a fruit involved in the transmission of T. cruzi. The post Gd T1-WI shows punctate enhancement. Knowledge of this pattern may be crucial to recognize this disease in immunocompromised patients from endemic areas.

Intracranial vessel wall magnetic resonance imaging features of infectious vasculitis.

Vasculitis is a complication of several infectious diseases affecting the central nervous system, which may result in ischemic and/or hemorrhagic stroke, transient ischemic attack, and aneurysm formation. The infectious agent may directly infect the endothelium, causing vasculitis, or indirectly affect the vessel wall through an immunological mechanism. The clinical manifestations of these complications usually overlap with those of non-infectious vascular diseases, making diagnosis challenging. Intracranial vessel wall magnetic resonance imaging (VWI) enables the evaluation of the vessel wall and the diseases that affect it, providing diagnostic data beyond luminal changes and enabling the identification of inflammatory changes in cerebral vasculitis. This technique demonstrates concentric vessel wall thickening and gadolinium enhancement, associated or not with adjacent brain parenchymal enhancement, in patients with vasculitis of any origin. It permits the detection of early alterations, even before a stenosis occurs. In this article, we review the intracranial vessel wall imaging features of infectious vasculitis of bacterial, viral, and fungal etiologies.

Arterial Spin Labeling: Techniques, Clinical Applications, and Interpretation.

Arterial spin labeling (ASL) is an emerging noninvasive MRI technique for assessing cerebral perfusion. An important advantage of ASL perfusion is the lack of a requirement for an exogenous tracer. ASL uses magnetically labeled water protons from arterial blood as an endogenous diffusible tracer. For this reason, ASL is an attractive perfusion imaging modality for children and for patients with contraindications or adverse reactions to gadolinium, patients with renal failure, and those who need repeated follow-up imaging. Another advantage of ASL is the possibility of quantifying cerebral blood flow, which provides an opportunity for comparative analysis among multiple longitudinal studies, unlike other MR perfusion techniques, which are semiquantitative and yield relative perfusion parameters. Advances in MRI technology and pulse sequence design have translated ASL beyond the research arena to successful clinical implementation. However, ASL is still underused in routine clinical practice. Some disadvantages of ASL include a lower signal-to-noise ratio and a longer acquisition time than those with dynamic susceptibility contrast-enhanced MRI. Additional factors limiting the use of ASL include variations in existing techniques and pulse sequence design, the complexity of implementation and postprocessing, insufficient experience with and/or knowledge of the potential clinical applications, and the absence of interpretation guidelines. The authors review the technical and physiologic basis of ASL perfusion, as well as artifacts, pitfalls, and its current clinical applications. A practical approach for interpreting ASL findings is also suggested.

Forging Connections in Latin America to Advance AI in Radiology.

The 1° Encontro Latino-Americano de IA em Saúde (1st Latin American Meeting on AI in Health) was held during the 2022 Jornada Paulista de Radiologia, the annual radiology meeting in the state of São Paulo. The event was created to foster discussion among Latin American countries about the complexity, challenges, and opportunities in developing and using artificial intelligence (AI) in those countries. Technological improvements in AI have created high expectations in health care. AI is recognized increasingly as a game changer in clinical radiology. To counter the fear that AI would "take over" radiology, the program included activities to educate radiologists. The development of AI in Latin America is in its early days, and although there are some pioneer cases, many regions still lack world-class technological infrastructure and resources. Legislation, regulation, and public policies in data privacy and protection, digital health, and AI are recent advances in many countries. The meeting program was developed with a broad scope, with expertise from different countries, backgrounds, and specialties, with the objective of encompassing all levels of complexity (from basic concepts to advanced techniques), perspectives (clinical, technical, ethical, and business), and specialties (both informatics and data science experts and the usual radiology clinical groups). It was an opportunity to connect with peers from other countries and share lessons learned about AI in health care in different countries and contexts. Keywords: Informatics, Use of AI in Education, Impact of AI on Education, Social Implications © RSNA, 2022.

Extra-pituitary midline structural abnormalities associated with ectopic posterior pituitary detected on a new rapid MRI protocol (FAST1.2).

Objective: Test if the MRI FAST1.2 protocol can detect extra-pituitary midline structural brain abnormalities in patients with ectopic posterior pituitary (EPP), and highlighting their radiological-laboratory correlations. Subjects and methods: Cross-sectional study of patients with EPP and control group. All individuals were submitted to FAST1.2, which combines the FAST1 protocol developed by our group with 3D T2DRIVE imaging. Results: We evaluated 36 individuals with EPP and 78 as control group. Pituitary stalk (PS) was identified in 7/36 patients in EPP group by FAST1, and in 24/36 patients in FAST1.2 (p < 0.001). FAST1 failed to detect PS in one individual in the control group, while the FAST1.2 defined the PS in all individuals. In EPP group, eleven had interhypothalamic adhesion (IHA), three septo-optic dysplasia, and one cerebellar malformation. We didn't observe higher frequency of panhypopituitarism or developmental delay in patients with IHA. In control group, three had pars intermedia cysts, one hydrocephalus, and one hypothalamic hamartoma. Conclusion: FAST1.2 allows confident recognition of midline structural abnormalities, including the pituitary stalk and IHA, thereby making MRI acquisition faster and with no need for contrast administration. IHA could be associated with defects in neuronal migration, as occur in patients with EPP, with no clinical significance.

Adding T2-Weighted Images to FAST1 Protocol to Evaluate the Anatomy of the Hypothalamic-Pituitary Region.

INTRODUCTION: Ectopic posterior pituitary (EPP) is a malformation of the hypothalamic-pituitary region presented as a spectrum from isolated growth hormone deficiency (GHD) to multiple pituitary hormone deficiencies (MPHDs). Our goal was to establish whether the FAST1.2 protocol, which combines the FAST1 protocol with 3D-T2 DRIVE images, could identify the pituitary stalk (PS) and the regional anatomy more accurately. METHODS: A retrospective study of 36 individuals with EPP and hypopituitarism and a control group of 78 individuals with eutopic posterior pituitary was conducted. All individuals were submitted to FAST1.2. The position and size of the pituitary lobes were described, and the presence/absence of the PS was confirmed. RESULTS: FAST1 identified the PS in 19% of individuals with EPP, while FAST1.2 identified the PS in 67% (p < 0.001). In the FAST1.2 protocol, the PS was visible in all control individuals. All EPP patients with isolated GHD had visible PS in FAST1.2, while only 58.6% of MPHD cases had visible PS. The size of the anterior lobe and the anteroposterior length of the posterior pituitary were smaller in the EPP group versus controls (p < 0.001). We noticed a reduced anterior pituitary lobe in both diameters in MPHD patients (p < 0.05). Six patients acquired new pituitary hormone deficiencies not recognized at the time of MRI; in this group, only 1 patient had a PS not visible in FAST1.2. DISCUSSION/CONCLUSION: The FAST1.2 protocol could prevent the misdiagnosis of idiopathic GHD in patients with short stature and could also be important in the progression to MPHD. The PS could be considered a predictor of hypopituitarism, but its use as an isolated indicator for the progression to MPHD is not recommended. Our results reinforce the use of the size of the anterior lobe as a predictor of hypopituitarism and a possible predictor of the degree of pituitary insufficiency. The FAST1.2 protocol could be used as an alternative to gadolinium administration, as a cheaper and faster method, while eliminating the potential risks associated with the administration of contrast media.

Corticospinal tract involvement in spinocerebellar ataxia type 3: a diffusion tensor imaging study.

PURPOSE: The aim of this study was to evaluate the integrity of the corticospinal tracts (CST) in patients with SCA3 and age- and gender-matched healthy control subjects using diffusion tensor imaging (DTI). We also looked at the clinical correlates of such diffusivity abnormalities. METHODS: We assessed 2 cohorts from different Brazilian centers: cohort 1 (n = 29) scanned in a 1.5 T magnet and cohort 2 (n = 91) scanned in a 3.0 T magnet. We used Pearson's coefficients to assess the correlation of CST DTI parameters and ataxia severity (expressed by SARA scores). RESULTS: Two different results were obtained. Cohort 1 showed no significant between-group differences in DTI parameters. Cohort 2 showed significant between-group differences in the FA values in the bilateral precentral gyri (p < 0.001), bilateral superior corona radiata (p < 0.001), bilateral posterior limb of the internal capsule (p < 0.001), bilateral cerebral peduncle (p < 0.001), and bilateral basis pontis (p < 0.001). There was moderate correlation between CST diffusivity parameters and SARA scores in cohort 2 (Pearson correlation coefficient: 0.40-0.59). CONCLUSION: DTI particularly at 3 T is able to uncover and quantify CST damage in SCA3. Moreover, CST microstructural damage may contribute with ataxia severity in the disease.

Case 278: Mutation in ROBO3 Gene-Horizontal Gaze Palsy and Progressive Scoliosis.

HistoryA 13-year-old girl was born to consanguineous parents. She presented with mild intellectual impairment, convergent strabismus, horizontal gaze palsy, and bilateral abducens palsy. Vertical gaze was preserved, and no abnormalities suggesting facial paralysis were noted. In addition, she reported progressive back pain since she was 5 years old. Other symptoms were denied. No medications or related drugs had been administered thus far. The patient underwent brain MRI for further evaluation. Current and previous spine radiographs were also reviewed.

Case 278.

HistoryA 13-year-old girl was born to consanguineous parents. She presented with mild intellectual impairment, convergent strabismus, horizontal gaze palsy, and bilateral abducens palsy. Vertical gaze was preserved, and no abnormalities suggesting facial paralysis were noted. In addition, she reported progressive back pain since she was 5 years old. Other symptoms were denied. No medications or related drugs had been administered thus far.

Multiphasic disseminated encephalomyelitis associated with herpes virus infection in a patient with TLR3 deficiency.

We report a case of a 14-year-old girl that presented headache, amaurosis, drowsiness, fever, vomiting and diffuse reduction of muscle strength. She had been diagnosed with ADEM one year before and had a previous diagnosis of Toll-Like 3 receptor deficiency. Cerebrospinal fluid analysis revealed pleocytosis (28/mm3, 12/mm3 red blood cells, 70% lymphocytes cells, 2% monocytes cells, 28% neutrophils), normal total protein (38 pg/mL) and normal glucose level (53/mm3). Studies for CSF oligoclonal bands and serum anti-MOG were negative but polymerase chain reaction (PCR) testing was positive for herpes virus 1. In the first ADEM episode, PCR for herpes virus was also positive. Magnetic resonance imaging (MRI) of the brain revealed disseminated hyperintense lesions on T2-weighted and FLAIR images in the white matter of frontal, parietal and temporal lobes, corresponding to extensive asymmetric areas of demyelination that produced mass effect and gadolinium enhancement. Electroencephalography demonstrated irregular diffuse and generalized slow-wave activity with predominance in frontal region. The diagnosis of multiphasic disseminated encephalomyelitis (MDEM) triggered by herpes simplex virus was made. Herpes virus is a neurotropic virus that can cause a wide variety of neurological infection-triggered autoimmune disorders and that is particularly damaging to the central nervous system in situations of impaired immune system. TLR3 is expressed in astrocytes and dendritic cells of the central nervous system and is essential for natural immunity to herpes simplex. TLR3-deficient patients have already been described with herpes simplex encephalitis. TLR3 deficiency may predispose and explain autoimmune and demyelinating manifestations induced by herpes virus. The association of multiphasic disseminated encephalomyelitis triggered by herpes virus in a patient with TLR3 deficiency has not been previously reported in the literature.

The Rare Neurocutaneous Disorders: Update on Clinical, Molecular, and Neuroimaging Features.

Phakomatoses, also known as neurocutaneous disorders, comprise a vast number of entities that predominantly affect structures originated from the ectoderm such as the central nervous system and the skin, but also the mesoderm, particularly the vascular system. Extensive literature exists about the most common phakomatoses, namely neurofibromatosis, tuberous sclerosis, von Hippel-Lindau and Sturge-Weber syndrome. However, recent developments in the understanding of the molecular underpinnings of less common phakomatoses have sparked interest in these disorders. In this article, we review the clinical features, current pathogenesis, and modern neuroimaging findings of melanophakomatoses, vascular phakomatoses, and other rare neurocutaneous syndromes that may also include tissue overgrowth or neoplastic predisposition.

Neuromyelitis Optica Spectrum Disorders: Spectrum of MR Imaging Findings and Their Differential Diagnosis.

Neuromyelitis optica (NMO) is an autoimmune demyelinating disorder for which the aquaporin-4 (AQP4) water channels are the major target antigens. Advances in the understanding of NMO have clarified several points of its pathogenesis, clinical manifestations, and imaging patterns. A major advance was the discovery of the AQP4 antibody, which is highly specific for this disorder. Descriptions of new clinical and radiologic features in seropositive patients have expanded the spectrum of NMO, and the term NMO spectrum disorder (NMOSD) has been adopted. NMOSD is now included in a widening list of differential diagnoses. Acknowledgment of NMOSD imaging patterns and their mimicry of disorders has been crucial in supporting early NMOSD diagnosis, especially for unusual clinical manifestations of this demyelinating disease. This pictorial review summarizes the wide imaging spectrum of NMOSD and its differential diagnosis, as well as its historical evolution, pathophysiology, and clinical manifestations. ©RSNA, 2018.

Toxic and Metabolic Myelopathies.

Myelopathy describes any neurologic deficit related to the spinal cord. It is most commonly caused by its compression by neoplasms, degenerative disc disease, trauma, or infection. Less common causes of myelopathy include spinal cord tumors, infection, inflammatory, neurodegenerative, vascular, toxic, and metabolic disorders. Conditions affecting the spinal cord must be recognized as early as possible to prevent progression that may lead to permanent disability. Biopsy is rarely performed, thus the diagnosis and management rely on patient׳s history, physical examination, laboratory results, and imaging findings. Here we review the clinical presentations, pathophysiological mechanisms, and magnetic resonance imaging findings of myelopathies related to metabolic or toxic etiologies.