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Journal of Medical Ultrasound 2023This article reviews the literature on different methods of prenatal ultrasound visualization of the optic chiasm (OC) and its applications. Prenatal imaging of the OC... (Review)
Review
This article reviews the literature on different methods of prenatal ultrasound visualization of the optic chiasm (OC) and its applications. Prenatal imaging of the OC is feasible from 19 to 37 weeks of gestation. Evaluation of the OC has been shown crucial in differentiating isolated agenesis of the septum pellucidum from septo-optic dysplasia. Multiple methods can be applied for imaging of the OC, including three-dimensional and two-dimensional ultrasounds in different views, as well as color Doppler. According to the literature, both transabdominal and transvaginal routes produce equally acceptable images. OC visualization might be challenging but can be achieved by developing a standard scanning protocol and raising awareness.
PubMed: 38025017
DOI: 10.4103/jmu.jmu_69_23 -
Frontiers in Oncology 2022To evaluate the accuracy and efficiency of Artificial-Intelligence (AI) segmentation in Total Marrow Irradiation (TMI) including contours throughout the head and neck...
PURPOSE
To evaluate the accuracy and efficiency of Artificial-Intelligence (AI) segmentation in Total Marrow Irradiation (TMI) including contours throughout the head and neck (H&N), thorax, abdomen, and pelvis.
METHODS
An AI segmentation software was clinically introduced for total body contouring in TMI including 27 organs at risk (OARs) and 4 planning target volumes (PTVs). This work compares the clinically utilized contours to the AI-TMI contours for 21 patients. Structure and image dicom data was used to generate comparisons including volumetric, spatial, and dosimetric variations between the AI- and human-edited contour sets. Conventional volume and surface measures including the Sørensen-Dice coefficient (Dice) and the 95% Hausdorff Distance (HD95) were used, and novel efficiency metrics were introduced. The clinical efficiency gains were estimated by the percentage of the AI-contour-surface within 1mm of the clinical contour surface. An unedited AI-contour has an efficiency gain=100%, an AI-contour with 70% of its surface<1mm from a clinical contour has an efficiency gain of 70%. The dosimetric deviations were estimated from the clinical dose distribution to compute the dose volume histogram (DVH) for all structures.
RESULTS
A total of 467 contours were compared in the 21 patients. In PTVs, contour surfaces deviated by >1mm in 38.6% ± 23.1% of structures, an average efficiency gain of 61.4%. Deviations >5mm were detected in 12.0% ± 21.3% of the PTV contours. In OARs, deviations >1mm were detected in 24.4% ± 27.1% of the structure surfaces and >5mm in 7.2% ± 18.0%; an average clinical efficiency gain of 75.6%. In H&N OARs, efficiency gains ranged from 42% in optic chiasm to 100% in eyes (unedited in all cases). In thorax, average efficiency gains were >80% in spinal cord, heart, and both lungs. Efficiency gains ranged from 60-70% in spleen, stomach, rectum, and bowel and 75-84% in liver, kidney, and bladder. DVH differences exceeded 0.05 in 109/467 curves at any dose level. The most common 5%-DVH variations were in esophagus (86%), rectum (48%), and PTVs (22%).
CONCLUSIONS
AI auto-segmentation software offers a powerful solution for enhanced efficiency in TMI treatment planning. Whole body segmentation including PTVs and normal organs was successful based on spatial and dosimetric comparison.
PubMed: 36110933
DOI: 10.3389/fonc.2022.970425 -
Clinical and Experimental Immunology Dec 2021Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system (CNS) associated with antibodies to aquaporin-4 (AQP4), which has... (Review)
Review
Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system (CNS) associated with antibodies to aquaporin-4 (AQP4), which has distinct clinical, radiological and pathological features, but also has some overlap with multiple sclerosis and myelin oligodendrocyte glycoprotein (MOG) antibody associated disease. Early recognition of NMOSD is important because of differing responses to both acute and preventive therapy. Magnetic resonance (MR) imaging has proved essential in this process. Key MR imaging clues to the diagnosis of NMOSD are longitudinally extensive lesions of the optic nerve (more than half the length) and spinal cord (three or more vertebral segments), bilateral optic nerve lesions and lesions of the optic chiasm, area postrema, floor of the IV ventricle, periaqueductal grey matter, hypothalamus and walls of the III ventricle. Other NMOSD-specific lesions are denoted by their unique morphology: heterogeneous lesions of the corpus callosum, 'cloud-like' gadolinium (Gd)-enhancing white matter lesions and 'bright spotty' lesions of the spinal cord. Other lesions described in NMOSD, including linear periventricular peri-ependymal lesions and patch subcortical white matter lesions, may be less specific. The use of advanced MR imaging techniques is yielding further useful information regarding focal degeneration of the thalamus and optic radiation in NMOSD and suggests that paramagnetic rim patterns and changes in normal appearing white matter are specific to MS. MR imaging is crucial in the early recognition of NMOSD and in directing testing for AQP4 antibodies and guiding immediate acute treatment decisions. Increasingly, MR imaging is playing a role in diagnosing seronegative cases of NMOSD.
Topics: Aquaporin 4; Autoantibodies; Humans; Immunoglobulin G; Magnetic Resonance Imaging; Neuromyelitis Optica; Optic Nerve; Spinal Cord; White Matter
PubMed: 34080180
DOI: 10.1111/cei.13630 -
Brain Communications 2023Achiasmia is a rare visual pathway maldevelopment with reduced decussation of the axons in the optic chiasm. Our aim was to investigate clinical characteristics,...
Achiasmia is a rare visual pathway maldevelopment with reduced decussation of the axons in the optic chiasm. Our aim was to investigate clinical characteristics, macular, optic nerve and brain morphology in achiasmia. A prospective, cross-sectional, observational study of 12 participants with achiasmia [8 males and 4 females; 29.6 ± 18.4 years (mean ± standard deviation)] and 24 gender-, age-, ethnicity- and refraction-matched healthy controls was done. Full ophthalmology assessment, eye movement recording, a high-resolution spectral-domain optical coherence tomography of the macular and optic disc, five-channel visual-evoked responses, eye movement recordings and MRI scans of the brain and orbits were acquired. Achiasmia was confirmed in all 12 clinical participants by visual-evoked responses. Visual acuity in this group was 0.63 ± 0.19 and 0.53 ± 0.19 for the right and left eyes, respectively; most participants had mild refractive errors. All participants with achiasmia had see-saw nystagmus and no measurable stereo vision. Strabismus and abnormal head position were noted in 58% of participants. Optical coherence tomography showed optic nerve hypoplasia with associated foveal hypoplasia in four participants. In the remaining achiasmia participants, macular changes with significantly thinner paracentral inner segment ( = 0.002), wider pit ( = 0.04) and visual flattening of the ellipsoid line were found. MRI demonstrated chiasmatic aplasia in 3/12 (25%), chiasmatic hypoplasia in 7/12 (58%) and a subjectively normal chiasm in 2/12 (17%). Septo-optic dysplasia and severe bilateral optic nerve hypoplasia were found in three patients with chiasmic aplasia/hypoplasia on MRI. In this largest series of achiasmia patients to date, we found for the first time that neuronal abnormalities occur already at the retinal level. Foveal changes, optic nerve hypoplasia and the midline brain anomaly suggest that these abnormalities could be part of the same spectrum, with different manifestations of events during foetal development occurring with varying severity.
PubMed: 37680693
DOI: 10.1093/braincomms/fcad219 -
Annals of Indian Academy of Neurology Oct 2022A large part of the central nervous system is involved in the normal functioning of the vision, and hence vision can be affected in a stroke patient. Transient visual...
A large part of the central nervous system is involved in the normal functioning of the vision, and hence vision can be affected in a stroke patient. Transient visual symptoms can likewise be a harbinger of stroke and prompt rapid evaluation for the prevention of recurrent stroke. A carotid artery disease can manifest as transient monocular visual loss (TMVL), central retinal artery occlusion (CRAO), anterior ischemic optic neuropathy or ocular ischemic syndrome (OIS). Stroke posterior to the optic chiasm can cause sectoranopias, quadrantanopias, or hemianopias, which can be either congruous or incongruous. Any stroke involving the dorsal stream (occipito-parietal lobe), or ventral stream (occipito-temporal lobe) can manifest with visuospatial perception deficits. Similarly, different ocular motility abnormalities can result from a stroke affecting the cerebrum, cerebellum, or brainstem. Among these deficits, vision and perception disorders are more difficult to overcome. Clinical, experimental, and neuroimaging studies have helped us to understand the anatomical basis, physiological dysfunction, and the underlying mechanisms of these neuro-ophthalmic signs.
PubMed: 36589034
DOI: 10.4103/aian.aian_157_22 -
Frontiers in Neuroscience 2023Glaucoma is the first major category of irreversible blinding eye illnesses worldwide. Its leading cause is the death of retinal ganglion cells and their axons, which... (Review)
Review
Glaucoma is the first major category of irreversible blinding eye illnesses worldwide. Its leading cause is the death of retinal ganglion cells and their axons, which results in the loss of vision. Research indicates that glaucoma affects the optic nerve and the whole visual pathway. It also reveals that degenerative lesions caused by glaucoma can be found outside the visual pathway. Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that can investigate the complete visual system, including alterations in the optic nerve, optic chiasm, optic tract, lateral geniculate nuclear, and optic radiation. In order to provide a more solid foundation for the degenerative characteristics of glaucoma, this paper will discuss the standard diagnostic techniques for glaucoma through a review of the literature, describe the use of DTI technology in glaucoma in humans and animal models, and introduce these techniques. With the advancement of DTI technology and its coupling with artificial intelligence, DTI represents a potential future for MRI technology in glaucoma research.
PubMed: 36816120
DOI: 10.3389/fnins.2023.1125638 -
Brain Tumor Research and Treatment Apr 2022Optic pathway gliomas (OPGs) are insidious, debilitating low-grade tumors. They can affect the optic nerve, optic chiasm, and optic tracts and can be sporadic or... (Review)
Review
Optic pathway gliomas (OPGs) are insidious, debilitating low-grade tumors. They can affect the optic nerve, optic chiasm, and optic tracts and can be sporadic or associated with neurofibromatosis type 1 (NF1). The location of OPGs within the optic pathway typically precludes complete resection or optimal radiation dose. Treatment is unnecessary for sporadic and NF1-related OPGs that do not cause visual impairments. Chemotherapy is the mainstay of treatment for patients with progressive disease. However, outcomes following standard treatments have been mixed, and standardized outcome measurements are lacking. In recent years, newer molecularly targeted therapies such as anti-vascular endothelial growth factor (VEGF) monoclonal antibody, mitogen-activated protein kinase (MAPK) inhibitor, and mammalian target of rapamycin (mTOR) inhibitor, represent a promising treatment modality.
PubMed: 35545829
DOI: 10.14791/btrt.2022.0006 -
Neurology India 2022Many potential causes of optic nerve inflammation exist, including typical and atypical causes, which require different management strategies.
BACKGROUND
Many potential causes of optic nerve inflammation exist, including typical and atypical causes, which require different management strategies.
OBJECTIVE
The objective of this study is to identify red flags that help differentiate typical from atypical optic neuritis (ON).
MATERIALS AND METHODS
This prospective study included 66 patients (100 eyes) with immune-mediated ON from January 2016 to June 2019, carefully excluding the nonimmune causes. The clinico-radiological features, investigations, therapy, and outcome were analyzed.
RESULTS
We evaluated 33 cases each of typical and atypical ON. The typical group included 29 idiopathic ON and four associated with multiple sclerosis. Atypical ON included 19 neuromyelitis optica (NMO), seven MOG-associated ON (MOG-ON), and others due to Sjogren's syndrome, granulomatous polyangiitis, sarcoidosis, and IgG4 disease. Atypical ON occurred significantly and more frequently with extremes of ages (<10 or >70 years), bilateral simultaneous or severe vision loss with early disc pallor, multiple attacks, symptoms/neuro-imaging indicating non-MS disease e.g., long segment ON/myelitis, large confluent lesions, the involvement of optic tract, chiasma, area postrema or diencephalon, and (pachy) meningitis. Systemic involvement and poor outcomes despite steroids and second-line immunosuppression were observed more often in the atypical ON.
CONCLUSIONS
The red flags indicating atypical ON are onset at extremes of age, multiple attacks, bilateral simultaneous or severe to very severe vision loss, early disc pallor, neurological symptoms, or imaging abnormalities suggesting non-MS disease, systemic involvement, and poor steroid responsiveness. The awareness might help the clinician promptly identify and escalate therapy to ensure a better outcome.
Topics: Aged; Humans; Autoantibodies; Myelin-Oligodendrocyte Glycoprotein; Neuromyelitis Optica; Optic Neuritis; Pallor; Prospective Studies; Vision Disorders
PubMed: 36352598
DOI: 10.4103/0028-3886.359189 -
Neurology India 2021Tuberculous meningitis (TBM) is associated with high mortality. A large proportion of patients with TBM, who survive, live with disabling neurological sequelae.... (Review)
Review
Tuberculous meningitis (TBM) is associated with high mortality. A large proportion of patients with TBM, who survive, live with disabling neurological sequelae. Hydrocephalus is one of the common complications of TBM, seen in up to 80% of patients. Hydrocephalus may be a presenting feature or may develop paradoxically after the commencement of antituberculosis treatment. The Hallmark pathological feature of TBM is a thick gelatinous exudate, dominantly present at basal parts of the brain. Exudate encases and strangulates cranial nerve trunks like optic nerve, optic chiasma, and vessels of the circle of Willis. Basal exudate also blocks the cerebrospinal fluid (CSF) flow in the brain, resulting in ventriculomegaly. It is often difficult to differentiate between two common types (communicating and obstructive) of hydrocephalus on basis of routine neuroimaging. Progressive hydrocephalus, clinically manifests with a potentially life-threatening high intracranial pressure. Patients with deteriorating vision loss and deteriorating consciousness, often need a surgical CSF diversion procedure (ventriculoperitoneal shunt or endoscopic third ventriculostomy) to be performed. CSF diversion may be life-saving. However, the long-term benefits of CSF diversion are largely unknown.
Topics: Brain; Humans; Hydrocephalus; Tuberculosis, Meningeal; Ventriculoperitoneal Shunt; Ventriculostomy
PubMed: 35102984
DOI: 10.4103/0028-3886.332275