The retrotransverse foramen (RTF) is a nonmetric variant of the atlas vertebra that can accommodate an anastomotic vertebral vein and occipital nerve. An understanding of this variation and its occurrence is crucial, as it could aid in explanation of the unidentified cause of the high prevalence of variability in this region. The aim of this meta-analysis was to obtain data on the prevalence of the RTF and its variations according to anatomy, sex, and ethnicity. A large-scale search was conducted through the major online databases to establish and determine the pool of studies reporting data relevant to the RTF. No date or language restrictions were applied. The data collection was categorized by prevalence, type (incomplete/complete), side, sex, ethnicity, laterality, and diameter. A total of 17 studies (n = 1979 subjects) were incorporated into our analysis. The overall pooled prevalence for a complete RTF was 11.4% and the overall pooled prevalence of an incomplete (partial) RTF was 9.6%. A complete RTF was most prevalent in Africa (Sub-Saharan population) (12.1%), followed by Europe (11.8%) and Asia (9.7%). As this variant occurs in a significant number of patients in all of the aforementioned populations, recognition, and awareness, especially with thorough investigation with computer tomography angiography (CTA) should be implemented, as it is the only possible way to visualize the possible contents of RTF.

Monkeypox is a zoonotic disease, endemic in central and west African regions, and has re-emerged, currently causing an outbreak as of May 2022. In this systematic review, we aimed to characterize the current face of the disease, with a detailed categorization of mucocutaneous, as well as systemic symptoms of the disease. We searched four main online databases with the keywords \"monkeypox\" and \"Orthopoxvirus\". A total of 46 articles were included, with a cumulative number of 1984 confirmed cases. Patients were predominantly men who have sex with men, who were mostly in their 30s, with a history of unprotected sexual contact or international travel. Among mucocutaneous manifestations, anogenital lesions were the most commonly observed, followed by lesions on the limbs, face, trunk, and palms or soles. Among lesion types, vesiculopustular, pustular or pseudo-pustular, vesicular-umbilicated and papular lesions were the most common, mainly presenting asynchronously, with less than 10 lesions on each patient. Almost all patients also reported systemic manifestations, namely fever, lymphadenopathy, fatigue, myalgia, headaches, pharyngitis, and proctitis. Sexual contact is the main pathway of transmission in the current outbreak, with viral shedding in bodily fluids playing a key role. We\'ve compared these idiosyncratic findings of the new outbreak with previous outbreaks. We\'ve also gathered and categorized images from our included studies to make a \"clinical atlas\" for this \"new\" face of monkeypox, which can be of utmost importance for clinicians to be familiarized with, and have a clear picture of monkeypox for their differential diagnoses.

This paper reviews almost three decades of work on atlasing and segmentation methods for subcortical structures in human brain MRI. In writing this survey, we have three distinct aims. First, to document the evolution of digital subcortical atlases of the human brain, from the early MRI templates published in the nineties, to the complex multi-modal atlases at the subregion level that are available today. Second, to provide a detailed record of related efforts in the automated segmentation front, from earlier atlas-based methods to modern machine learning approaches. And third, to present a perspective on the future of high-resolution atlasing and segmentation of subcortical structures in in vivo human brain MRI, including open challenges and opportunities created by recent developments in machine learning.

Vascular malformations are frequent in the head and neck region, affecting the nervous system. The wide range of therapeutic approaches demand the correct anatomical, morphological, and functional characterization of these lesions supported by imaging. Using a systematic search protocol in PubMed, Google Scholar, Ebsco, Redalyc, and SciELO, the authors extracted clinical studies, review articles, book chapters, and case reports that provided information about vascular cerebral malformations, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 385,614 articles were grouped; using the inclusion and exclusion criteria, three of the authors independently selected 51 articles about five vascular cerebral malformations: venous malformation, brain capillary telangiectasia, brain cavernous angiomas, arteriovenous malformation, and leptomeningeal angiomatosis as part of Sturge-Weber syndrome. We described the next topics-\"definition\", \"etiology\", \"pathophysiology\", and \"treatment\"-with a focus on the relationship with the imaging approach. We concluded that the correct anatomical, morphological, and functional characterization of cerebral vascular malformations by means of various imaging studies is highly relevant in determining the therapeutic approach, and that new lines of therapeutic approaches continue to depend on the imaging evaluation of these lesions.

This narrative review article was conducted to lay out a summarized but exhaustive review of current literature over mucocutaneous manifestations in 4 dimensions of SARS-CoV-2 pandemic: virus itself, treatment-related, vaccine-induced, and alteration of chronic dermatologic diseases following infection. Virus and vaccine-related were mainly self-limited and non-severe. Treatment-related reactions could be life-threatening.

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Osteochondroma is a common benign bone tumor that is rarely seen in the spine, especially in the atlas. Although most solitary atlas osteochondromas have no symptoms, some exostosis may cause severe clinical symptoms that need treatment within the spine. Here, we report a 21-year-old male who presented with apsychia as well as numbness in his right upper and lower limbs for 2 months. The patient reported a history of neck trauma 10 years ago. He received a posterior laminectomy without reconstruction later, and the symptoms improved immediately. During a 32 month follow-up, there was no recurrence of the osteochondroma. Novel techniques for the treatment of this case were applied: simulated surgical resection using 3-Matic 9.0 software, 3D printed model, 3D Digital Image Microscopy, and piezoelectric surgery. These novel techniques provided significant benefits to the patients, the surgeon, and medical education.

UNASSIGNED: Numerous techniques of C1 lateral mass screw placement have been described. We sought to delineate the radiographic angle of safety medially and laterally and describe a novel surgical technique of C1 lateral mass screw placement. We sought to (I) determine the angle of safety medially and laterally of the C1 lateral mass; (II) assess the size available of the lateral mass in the AP and coronal planes; (III) describe novel technique of insertion of a C1 lateral mass screw utilizing navigation and a novel start point.
UNASSIGNED: We retrospectively reviewed cervical computed tomography (CT) images of normal adults. Radiographic measurements were then obtained using these images including the angle (degrees) of safety medially and lateral of the C1 lateral mass bilaterally, as well as the length and width (mm) of the C1 lateral masses. A novel surgical technique was used by identifying the confluence of the medial aspect of the posterior arch and the lateral mass. This confluence is then marked out as the C1 screw start point. Under navigation guidance, lateral mass screws were placed with 0 degrees of medial-lateral angulation from posterior to anterior.
UNASSIGNED: Forty-five patients with a mean age of 52.6±25.6 years (33% female) were included. The mean medial and lateral angle of safety of the C1 lateral mass bilaterally was 23±3.8 degrees and 32±5 degrees, respectively. Average length and width of the lateral mass was 17.7 and 13.3 mm respectively.
UNASSIGNED: This study describes the radiographic window of safety medially and laterally for safe and reproducible placement of C1 lateral mass screws. Further, a novel technique using a medial start point and navigation guidance with 0 degrees of angulation in the coronal plane is described. Further research is required to assess outcomes of patients utilizing this method as well as biomechanical studies to assess this construct strength compared to others that are frequently used.

UNASSIGNED: Isolated symptomatic cervical stenosis of the atlas is quite rare; there have been 11 cases reported in literature.
UNASSIGNED: A 76-year-old male presented with myelopathy attributed to C1 arch stenosis. Neuroimaging studies revealed posterior atlas compression of the spinal cord. Following a cervical laminectomy involving excision of the arch of the atlas, and the patient\'s symptoms resolved.
UNASSIGNED: C1 stenosis resulting in cervical myelopathy due to posterior compression from the arch of the atlas is easily missed. Notably, C1 arch laminectomy may be very effective in resolving this entity.

Dual-energy X-ray absorptiometry is currently the standard and validated tool for measurement of bone mineral density and for the evaluation of osteoporosis. Current densitometry scanners based on dual-energy X-ray absorptiometry method produce two X-ray beams with different energies to differentiate the overlapped soft tissue and bony structures, by creating two different attenuation profiles. Procedural guidelines are available to technicians and physicians to guarantee the best practice, including consistent positioning during scanning and standard reporting. However, similar to other imaging modalities, dual-energy X-ray absorptiometry may be influenced by technical errors, and thus, imaging artifacts may arise and accuracy and precision of the results may be influenced. This issue may, in turn, affect the final result and interpretation. Hence, the article is arranged with the intention of presenting some less common and rare technical and patient-related sources of error and resultant artifacts, from poor patient preparation to acquisition and data processing. Where appropriate, the corresponding tables of densitometric results (bone mineral density) and statistical parameters (T- and Z-scores) are provided.