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Cureus Nov 2023Giant cell arteritis (GCA) is a medium- and large-vessel systemic vasculitis. It is common among people aged 50 years and older. GCA presents with cranial manifestations...
Giant cell arteritis (GCA) is a medium- and large-vessel systemic vasculitis. It is common among people aged 50 years and older. GCA presents with cranial manifestations of headache, visual symptoms, cerebrovascular events, and systemic manifestations. The diagnosis of GCA is confirmed with a positive temporal artery biopsy. Treatment of GCA consists of high-dose steroids with slow tapering over 18 to 24 months and steroid-sparing therapy to maintain remission. Due to the risk of the most feared complication of GCA, irreversible visual loss, once GCA is suspected, high-dose steroids should be commenced immediately, and a temporal artery biopsy should be done not beyond one to two weeks after starting steroids to avoid the effects of steroids on the result of the temporal artery biopsy. There are orbital radiological findings reported in patients with an atypical presentation of GCA on MRI; these findings include non-specific orbital inflammation, optic nerve inflammation, optic nerve sheath inflammation, and optic chiasm enhancement.
PubMed: 38152789
DOI: 10.7759/cureus.49507 -
Journal of Applied Clinical Medical... Jan 2024Obvious inconsistencies in auto-segmentations exist among various AI software. In this study, we have developed a novel convolutional neural network (CNN) fine-tuning...
PURPOSE
Obvious inconsistencies in auto-segmentations exist among various AI software. In this study, we have developed a novel convolutional neural network (CNN) fine-tuning workflow to achieve precise and robust localized segmentation.
METHODS
The datasets include Hubei Cancer Hospital dataset, Cetuximab Head and Neck Public Dataset, and Québec Public Dataset. Seven organs-at-risks (OARs), including brain stem, left parotid gland, esophagus, left optic nerve, optic chiasm, mandible, and pharyngeal constrictor, were selected. The auto-segmentation results from four commercial AI software were first compared with the manual delineations. Then a new multi-scale lightweight residual CNN model with an attention module (named as HN-Net) was trained and tested on 40 samples and 10 samples from Hubei Cancer Hospital, respectively. To enhance the network's accuracy and generalization ability, the fine-tuning workflow utilized an uncertainty estimation method for automatic selection of candidate samples of worthiness from Cetuximab Head and Neck Public Dataset for further training. The segmentation performances were evaluated on the Hubei Cancer Hospital dataset and/or the entire Québec Public Dataset.
RESULTS
A maximum difference of 0.13 and 0.7 mm in average Dice value and Hausdorff distance value for the seven OARs were observed by four AI software. The proposed HN-Net achieved an average Dice value of 0.14 higher than that of the AI software, and it also outperformed other popular CNN models (HN-Net: 0.79, U-Net: 0.78, U-Net++: 0.78, U-Net-Multi-scale: 0.77, AI software: 0.65). Additionally, the HN-Net fine-tuning workflow by using the local datasets and external public datasets further improved the automatic segmentation with the average Dice value by 0.02.
CONCLUSION
The delineations of commercial AI software need to be carefully reviewed, and localized further training is necessary for clinical practice. The proposed fine-tuning workflow could be feasibly adopted to implement an accurate and robust auto-segmentation model by using local datasets and external public datasets.
Topics: Humans; Workflow; Cetuximab; Image Processing, Computer-Assisted; Tomography, X-Ray Computed; Neural Networks, Computer; Organs at Risk
PubMed: 38128058
DOI: 10.1002/acm2.14248 -
Physics and Imaging in Radiation... Oct 2023Tools for auto-segmentation in radiotherapy are widely available, but guidelines for clinical implementation are missing. The goal was to develop a workflow for...
BACKGROUND AND PURPOSE
Tools for auto-segmentation in radiotherapy are widely available, but guidelines for clinical implementation are missing. The goal was to develop a workflow for performance evaluation of three commercial auto-segmentation tools to select one candidate for clinical implementation.
MATERIALS AND METHODS
One hundred patients with six treatment sites (brain, head-and-neck, thorax, abdomen, and pelvis) were included. Three sets of AI-based contours for organs-at-risk (OAR) generated by three software tools and manually drawn expert contours were blindly rated for contouring accuracy. The dice similarity coefficient (DSC), the Hausdorff distance, and a dose/volume evaluation based on the recalculation of the original treatment plan were assessed. Statistically significant differences were tested using the Kruskal-Wallis test and the post-hoc Dunn Test with Bonferroni correction.
RESULTS
The mean DSC scores compared to expert contours for all OARs combined were 0.80 ± 0.10, 0.75 ± 0.10, and 0.74 ± 0.11 for the three software tools. Physicians' rating identified equivalent or superior performance of some AI-based contours in head (eye, lens, optic nerve, brain, chiasm), thorax (e.g., heart and lungs), and pelvis and abdomen (e.g., kidney, femoral head) compared to manual contours. For some OARs, the AI models provided results requiring only minor corrections. Bowel-bag and stomach were not fit for direct use. During the interdisciplinary discussion, the physicians' rating was considered the most relevant.
CONCLUSION
A comprehensive method for evaluation and clinical implementation of commercially available auto-segmentation software was developed. The in-depth analysis yielded clear instructions for clinical use within the radiotherapy department.
PubMed: 38111502
DOI: 10.1016/j.phro.2023.100515 -
Development (Cambridge, England) Jan 2024Binocular vision requires the segregation of retinal ganglion cell (RGC) axons extending from the retina into the ipsilateral and contralateral optic tracts. RGC axon...
Binocular vision requires the segregation of retinal ganglion cell (RGC) axons extending from the retina into the ipsilateral and contralateral optic tracts. RGC axon segregation occurs at the optic chiasm, which forms at the ventral diencephalon midline. Using expression analyses, retinal explants and genetically modified mice, we demonstrate that CXCL12 (SDF1) is required for axon segregation at the optic chiasm. CXCL12 is expressed by the meninges bordering the optic pathway, and CXCR4 by both ipsilaterally and contralaterally projecting RGCs. CXCL12 or ventral diencephalon meninges potently promoted axon outgrowth from both ipsilaterally and contralaterally projecting RGCs. Further, a higher proportion of axons projected ipsilaterally in mice lacking CXCL12 or its receptor CXCR4 compared with wild-type mice as a result of misrouting of presumptive contralaterally specified RGC axons. Although RGCs also expressed the alternative CXCL12 receptor ACKR3, the optic chiasm developed normally in mice lacking ACKR3. Our data support a model whereby meningeal-derived CXCL12 helps drive axon growth from CXCR4-expressing RGCs towards the diencephalon midline, enabling contralateral axon growth. These findings further our understanding of the molecular and cellular mechanisms controlling optic pathway development.
Topics: Animals; Mice; Axons; Diencephalon; Optic Chiasm; Retina; Retinal Ganglion Cells; Visual Pathways
PubMed: 38095299
DOI: 10.1242/dev.202446 -
Frontiers in Endocrinology 2023Hypophysitis is reported in 8.5%-14% of patients receiving combination immune checkpoint inhibition (cICI) but can be a diagnostic challenge. This study aimed to assess...
INTRODUCTION
Hypophysitis is reported in 8.5%-14% of patients receiving combination immune checkpoint inhibition (cICI) but can be a diagnostic challenge. This study aimed to assess the role of routine diagnostic imaging performed during therapeutic monitoring of combination anti-CTLA-4/anti-PD-1 treatment in the identification of hypophysitis and the relationship of imaging findings to clinical diagnostic criteria.
METHODS
This retrospective cohort study identified patients treated with cICI between January 2016 and January 2019 at a quaternary melanoma service. Medical records were reviewed to identify patients with a documented diagnosis of hypophysitis based on clinical criteria. Available structural brain imaging with magnetic resonance imaging (MRI) or computed tomography (CT) of the brain and 2-deoxy-2-[F]fluoro-D-glucose positron emission tomography with computed tomography (FDG-PET/CT) were assessed retrospectively. The main radiological outcome measures were a relative change in pituitary size or FDG uptake temporally attributed to cICI.
RESULTS
There were 162 patients (median age 60 years, 30% female) included. A total of 100 and 134 had serial CT/MRI of the brain and FDG-PET/CT, respectively. There were 31 patients who had a documented diagnosis of hypophysitis and an additional 20 who had isolated pituitary imaging findings. The pituitary gland enlargement was mild, and the largest absolute gland size was 13 mm, with a relative increase of 7 mm from baseline. There were no cases of optic chiasm compression. Pituitary enlargement and increased FDG uptake were universally transient. High-dose glucocorticoid treatment for concurrent irAEs prevented assessment of the pituitary-adrenal axis in 90% of patients with isolated imaging findings.
CONCLUSION
Careful review of changes in pituitary characteristics on imaging performed for assessment of therapeutic response to iICI may lead to increased identification and more prompt management of cICI-induced hypophysitis.
Topics: Humans; Female; Middle Aged; Male; Immune Checkpoint Inhibitors; Retrospective Studies; Positron Emission Tomography Computed Tomography; Fluorodeoxyglucose F18; Hypophysitis; Pituitary Diseases; Neoplasms
PubMed: 38093958
DOI: 10.3389/fendo.2023.1295865 -
Cureus Dec 2023Objective This study aims to thoroughly assess the radiation dose distribution to critical organs in patients with nasopharyngeal carcinoma, focusing on the correlation...
Objective This study aims to thoroughly assess the radiation dose distribution to critical organs in patients with nasopharyngeal carcinoma, focusing on the correlation between the radiation dosages for the various organs at risk (OARs) in nasopharyngeal cancer patients. Methods We meticulously analysed a dataset comprising 38 nasopharyngeal carcinoma patients, focusing on radiation dosages measured in Gray (Gy) and volumetric data in cubic centimetres (cc) of critical organs, including the lens, brainstem, spinal cord, optic nerve, optic chiasm, and cochlea. A detailed exploratory data analysis approach encompassed univariate, bivariate, and multivariate techniques. Results Our analysis revealed several key findings. The mean and median values across various dose measurements were closely aligned, indicating symmetrical distributions with minimal skewness. The histograms further corroborated this, showing evenly distributed dose values across different anatomical regions. The correlation matrix highlighted varying degrees of interrelationships between the doses, with some showing strong correlations while others exhibited minimal or no correlation. The 3D scatter plot provided a view of the multi-dimensional dose relationships, with a specific focus on the spinal cord, lens, and brainstem doses. The bivariate scatter plots revealed symmetrical distributions between the right and left lens doses and more complex relationships involving the brainstem and spinal cord, illustrating the intricacies of dose distribution in radiation therapy. Conclusion Our findings reveal distinct radiation exposure patterns to OARs of nasopharyngeal carcinoma. This research emphasises the need for tailored radiation therapy planning to achieve optimal clinical outcomes while safeguarding vital organs.
PubMed: 38053989
DOI: 10.7759/cureus.49882 -
Radiology Case Reports Jan 2024The manuscript describes a case of Cavernous Malformation in the optic pathway which is extremely rare, accounting for less than 1% of central nervous system cavernomas....
The manuscript describes a case of Cavernous Malformation in the optic pathway which is extremely rare, accounting for less than 1% of central nervous system cavernomas. This case report highlights a patient initially diagnosed with a glioma, but subsequent MRI changes and extensive analysis ruled in favor of a hemorrhagic optic neuropathy caused by an optic nerve cavernoma. The patient experienced temporary vision loss but fully regained her vision within a week. Based on clinical, biochemical, and radiological findings, it was confirmed as a rare case of optic nerve cavernoma, and the patient was managed expectantly due to her complete recovery of vision. Follow-up imaging after 1 year indicated a stable lesion with evolving characteristics consistent with a cavernoma. This study provides an informative review of the condition and highlights the key radiologic features of this disease.
PubMed: 38028314
DOI: 10.1016/j.radcr.2023.09.018 -
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 -
JCEM Case Reports Nov 2023Crooke cell adenoma (CCA) is a rare and aggressive subtype of a corticotroph adenoma, which requires lifetime surveillance. There have been 106 cases of CCAs reported in...
Crooke cell adenoma (CCA) is a rare and aggressive subtype of a corticotroph adenoma, which requires lifetime surveillance. There have been 106 cases of CCAs reported in the English literature. We describe 2 cases of CCA, a 48-year-old man and an 84-year-old woman who both presented with binocular diplopia and temple pain. Neither case had clinical Cushing syndrome. Laboratory values for the 48-year-old man revealed, adrenocorticotropin (ACTH) 103 pg/mL (22 pmol/L) (RR: 7-63 pg/mL) and evening cortisol 14 µg/dL (386 nmol/L) (RR: 2.7-10.5 µg/dL). Computed tomography imaging demonstrated a mass adjacent to the right cavernous sinus extending into the sphenoid sinus. He underwent tumor resection with adjuvant radiation and has had a stable residual tumor for 4 years. Preoperative laboratory values for the 84-year-old woman revealed, ACTH 69 pg/mL (15 pmol/L) (RR: 7-63 pg/mL) and evening cortisol 16.2 µg/dL (447 nmol/L) (RR: 2.7-10.5 µg/dL). Brain magnetic resonance imaging revealed, a mass compressing the optic chiasm. She underwent resection and has had a stable residual tumor for 2 years. Surgical pathology in both cases revealed cytoplasmic hyaline deposits of more than 50% of the tumor cells, consistent with CCA. The CCA although rare, should be considered when evaluating cases with subclinical Cushing disease and visual symptoms.
PubMed: 38021080
DOI: 10.1210/jcemcr/luad114 -
Investigative Ophthalmology & Visual... Nov 2023Perception of the motion quartet (MQ) alternates between horizontal and vertical motion, with a bias toward vertical motion. This vertical bias has been explained by the...
PURPOSE
Perception of the motion quartet (MQ) alternates between horizontal and vertical motion, with a bias toward vertical motion. This vertical bias has been explained by the dominance of intrahemispheric processing. In albinism, each hemisphere receives input from both visual hemifields owing to enhanced crossing of the optic nerves at the optic chiasm. This might affect the perception of the ambiguous MQ and particularly the vertical bias.
METHODS
The effect of optic nerve misrouting in persons with albinism and nystagmus (PWA, n = 14) on motion perception for MQ was compared with healthy controls (HC; n = 11) and with persons with nystagmus in the absence of optic nerve misrouting (PWN; n = 12). We varied the ratio of horizontal and vertical distances of MQ dots (aspect ratio [AR]) between 0.75 and 1.25 and compared the percentages of horizontal and vertical motion percepts as a function of AR between groups.
RESULTS
For HC, the probability of vertical motion perception increased as a sigmoid function with increasing AR exhibiting the expected vertical percept bias (mean, 58%; median, 54%; vertical motion percepts). PWA showed a surprisingly strong horizontal bias independent of the AR with a mean of 11% (median, 10%) vertical motion percepts. The PWN was in between PWA and HC, with a mean of 34% (median, 47%) vertical perception. Nystagmus alone is unlikely to explain this pattern of results because PWA and PWN had comparable fixation stabilities.
CONCLUSIONS
The strong horizontal bias observed in PWA and PWN might partly result from the horizontal nystagmus. The even stronger horizontal bias in PWA indicates that the intrahemispherical corepresentation of both visual hemifields may play an additional role. The altered perception of the MQ in PWA opens opportunities to (i) understand the interplay of stability and plasticity in altered visual pathway conditions and (ii) identify visual pathway abnormalities with a perception-based test using the MQ.
Topics: Humans; Albinism; Motion Perception; Nystagmus, Pathologic; Optic Chiasm; Optic Nerve
PubMed: 38015177
DOI: 10.1167/iovs.64.14.39