-
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 -
Journal of Neuroscience Methods Jan 2024Blood perfusion of the optic nerve (ON) plays a key role in many optic neuropathies. Microvascular changes precede or accompany neuronal changes, and detecting these...
BACKGROUND
Blood perfusion of the optic nerve (ON) plays a key role in many optic neuropathies. Microvascular changes precede or accompany neuronal changes, and detecting these changes at an early stage may facilitate early treatment to avoid blindness. However, the quantification of ON blood perfusion remains a challenge. This study aimed to evaluate the viability of three-dimensional pseudocontinuous arterial spin labelling (3D-pCASL) MRI for the quantification of ON blood flow (BF).
NEW METHOD
The ON segmentation was performed using nnFormer on a cohort of ten participants (4 males, 6 females, 25-59 years old). Subsequently, the mean BF of each ON segment was calculated using whole brain 3D-pCASL image data.
RESULTS
The average ON-BF values of the left and right intraorbital segments, left and right intracanalicular segments, left and right intracranial segments, optic chiasma, and left and right optic tract were 41.308 mL/100 g/min, 43.281 mL/100 g/min, 53.188 mL/100 g/min, 57.202 mL/100 g/min, 45.089 mL/100 g/min, 49.554 mL/100 g/min, 42. 326 mL/100 g/min, 43.831 mL/100 g/min and 45.176 mL/100 g/min, respectively. The ON-BF correlated with cerebral BF (r = 0.503, p = 0.024).
COMPARISON WITH EXISTING METHOD(S)
The 3D-pCASL can measure tissue microvascular blood perfusion in absolute quantitative units with good test-retest repeatability over a wide field of view and without restrictions on depth. The use of the nnFormer makes the measurement easy, objective and reproducible.
CONCLUSIONS
The study showed that, 3D-pCASL may be a promising tool for detecting abnormal ON-BF. In particular, 3D-pCASL coupled with the nnFormer provides an objective, reproducible, and reliable method to quantify BF in ON.
Topics: Male; Female; Humans; Adult; Middle Aged; Magnetic Resonance Angiography; Spin Labels; Magnetic Resonance Imaging; Cerebrovascular Circulation; Optic Nerve
PubMed: 37952831
DOI: 10.1016/j.jneumeth.2023.110007 -
Asian Journal of Surgery Feb 2024
Topics: Humans; Optic Chiasm; Optic Nerve; Foot; Lower Extremity
PubMed: 37945403
DOI: 10.1016/j.asjsur.2023.10.090 -
Frontiers in Oncology 2023Radiation therapy is a common treatment option for Head and Neck Cancer (HNC), where the accurate segmentation of Head and Neck (HN) Organs-AtRisks (OARs) is critical...
INTRODUCTION
Radiation therapy is a common treatment option for Head and Neck Cancer (HNC), where the accurate segmentation of Head and Neck (HN) Organs-AtRisks (OARs) is critical for effective treatment planning. Manual labeling of HN OARs is time-consuming and subjective. Therefore, deep learning segmentation methods have been widely used. However, it is still a challenging task for HN OARs segmentation due to some small-sized OARs such as optic chiasm and optic nerve.
METHODS
To address this challenge, we propose a parallel network architecture called PCG-Net, which incorporates both convolutional neural networks (CNN) and a Gate-Axial-Transformer (GAT) to effectively capture local information and global context. Additionally, we employ a cascade graph module (CGM) to enhance feature fusion through message-passing functions and information aggregation strategies. We conducted extensive experiments to evaluate the effectiveness of PCG-Net and its robustness in three different downstream tasks.
RESULTS
The results show that PCG-Net outperforms other methods, improves the accuracy of HN OARs segmentation, which can potentially improve treatment planning for HNC patients.
DISCUSSION
In summary, the PCG-Net model effectively establishes the dependency between local information and global context and employs CGM to enhance feature fusion for accurate segment HN OARs. The results demonstrate the superiority of PCGNet over other methods, making it a promising approach for HNC treatment planning.
PubMed: 37927463
DOI: 10.3389/fonc.2023.1177788 -
Molecular Characterization of Neurogranin (NRGN) Gene from Red‑Bellied Pacu (Piaractus brachypomus).Molecular Neurobiology May 2024Neurogranin (NRGN) is a small brain protein expressed in various telencephalic areas and plays an essential role in synaptic plasticity by regulating the availability of...
Neurogranin (NRGN) is a small brain protein expressed in various telencephalic areas and plays an essential role in synaptic plasticity by regulating the availability of calmodulin (CaM). The study aims to characterize the neurogranin gene in Colombian native fish, red-bellied pacu, Piaractus brachypomus, its basal tissue expression and differential expression in brain injury and sublethal toxicity by organophosphates. NRGN gene contains an open reading frame of 183 nucleotides encoding for 60 amino acids. Bioinformatics analysis showed an IQ motif necessary in the interaction with CaM. NRGN mRNA was detected in tissues with higher expression in brain, gills, and head kidney. In brain regions, NRGN showed high expression in the telencephalon (TE) and olfactory bulb (OB). In the sublethal toxicity experiment, NRGN mRNA was upregulated in individuals under organophosphate exposure in the OB and optic chiasm (OC). In brain injury experiment, NRGN showed upregulation at 14 days in OC and at 24 h and 7 days in TE. These findings demonstrate the differential expression of NRGN under different experimental conditions which make it a candidate for a biomarker in the brain of P. brachypomus.
Topics: Animals; Neurogranin; RNA, Messenger; Amino Acid Sequence; Phylogeny; Brain; Characiformes; Fish Proteins
PubMed: 37922064
DOI: 10.1007/s12035-023-03700-5 -
Biomedical Engineering Online Nov 2023The contouring of organs at risk (OARs) in head and neck cancer radiation treatment planning is a crucial, yet repetitive and time-consuming process. Recent studies have... (Meta-Analysis)
Meta-Analysis Review
PURPOSE
The contouring of organs at risk (OARs) in head and neck cancer radiation treatment planning is a crucial, yet repetitive and time-consuming process. Recent studies have applied deep learning (DL) algorithms to automatically contour head and neck OARs. This study aims to conduct a systematic review and meta-analysis to summarize and analyze the performance of DL algorithms in contouring head and neck OARs. The objective is to assess the advantages and limitations of DL algorithms in contour planning of head and neck OARs.
METHODS
This study conducted a literature search of Pubmed, Embase and Cochrane Library databases, to include studies related to DL contouring head and neck OARs, and the dice similarity coefficient (DSC) of four categories of OARs from the results of each study are selected as effect sizes for meta-analysis. Furthermore, this study conducted a subgroup analysis of OARs characterized by image modality and image type.
RESULTS
149 articles were retrieved, and 22 studies were included in the meta-analysis after excluding duplicate literature, primary screening, and re-screening. The combined effect sizes of DSC for brainstem, spinal cord, mandible, left eye, right eye, left optic nerve, right optic nerve, optic chiasm, left parotid, right parotid, left submandibular, and right submandibular are 0.87, 0.83, 0.92, 0.90, 0.90, 0.71, 0.74, 0.62, 0.85, 0.85, 0.82, and 0.82, respectively. For subgroup analysis, the combined effect sizes for segmentation of the brainstem, mandible, left optic nerve, and left parotid gland using CT and MRI images are 0.86/0.92, 0.92/0.90, 0.71/0.73, and 0.84/0.87, respectively. Pooled effect sizes using 2D and 3D images of the brainstem, mandible, left optic nerve, and left parotid gland for contouring are 0.88/0.87, 0.92/0.92, 0.75/0.71 and 0.87/0.85.
CONCLUSIONS
The use of automated contouring technology based on DL algorithms is an essential tool for contouring head and neck OARs, achieving high accuracy, reducing the workload of clinical radiation oncologists, and providing individualized, standardized, and refined treatment plans for implementing "precision radiotherapy". Improving DL performance requires the construction of high-quality data sets and enhancing algorithm optimization and innovation.
Topics: Humans; Deep Learning; Organs at Risk; Head; Head and Neck Neoplasms; Algorithms; Image Processing, Computer-Assisted
PubMed: 37915046
DOI: 10.1186/s12938-023-01159-y -
JCEM Case Reports Jul 2023Olfactory neuroblastomas, or esthesioneuroblastomas, are rare and aggressive malignant tumors that typically arise from the olfactory neuroepithelium in the upper nasal...
Olfactory neuroblastomas, or esthesioneuroblastomas, are rare and aggressive malignant tumors that typically arise from the olfactory neuroepithelium in the upper nasal cavity. In rare instances, they can be ectopic originating from areas outside the upper nasal cavity such as the sellar region. These tumors, also known as primary sellar neuroblastomas, may be mistaken for pituitary macroadenomas. We present a rare case of a primary sellar neuroblastoma in a 30-year-old woman with a prior diagnosis of presumed prolactinoma, status post transsphenoidal resection, with residual visual deficits, who presented with worsening vision and headaches. Pituitary magnetic resonance imaging showed a large sellar mass causing compression of the optic chiasm, and invasion of the right cavernous sinus and bilateral cavernous internal carotid arteries. The patient underwent a second transsphenoidal resection. Postoperatively, she developed central adrenal insufficiency, central hypothyroidism, central hypogonadism, and transient syndrome of inappropriate antidiuretic hormone secretion. Owing to rapid tumor regrowth, she underwent a craniotomy with plans for radiation treatment. This condition is challenging to diagnose and has poorly defined clinical management guidelines. An early, aggressive approach with surgical intervention is recommended.
PubMed: 37908997
DOI: 10.1210/jcemcr/luad081 -
JCEM Case Reports Jul 2023Hypopituitarism due to an internal carotid artery (ICA) aneurysm is rare. We present a case of hypopituitarism and hyperprolactinemia due to a giant right ICA aneurysm....
Hypopituitarism due to an internal carotid artery (ICA) aneurysm is rare. We present a case of hypopituitarism and hyperprolactinemia due to a giant right ICA aneurysm. A 56-year-old woman with a history of primary hypothyroidism presented with fatigue, right-sided headache, and blurred vision. Magnetic resonance (MR) of the brain revealed a sellar mass measuring 3.5 × 2.2 cm involving the right cavernous sinus. Initial neurologic examination was unremarkable, and her biochemical evaluation revealed secondary adrenal insufficiency, central hypogonadism, low serum free thyroxine, and mildly elevated serum prolactin, consistent with stalk effect. Hydrocortisone therapy was started for secondary adrenal insufficiency and her levothyroxine dose was adjusted. The patient was referred to neurosurgery for surgical management of her sellar lesion. Preoperative computed tomography angiography (CTA) of the brain revealed a right ICA aneurysm that contacted the optic chiasm and displaced the pituitary gland. The aneurysm was embolized and diverting stents were placed. Repeat laboratory tests showed resolution of the patient's secondary adrenal insufficiency, normalization of serum prolactin, and an increase in serum gonadotropin concentrations to the postmenopausal range. This case highlights that not all sellar lesions are pituitary adenomas, and CTA should be performed in the evaluation of large cavernous sinus lesions to exclude ICA aneurysm.
PubMed: 37908996
DOI: 10.1210/jcemcr/luad076 -
JCEM Case Reports Mar 2023A 31-year-old gentleman presented with clinical hyperthyroidism, goiter, bitemporal hemianopia, and discordant thyroid function test. The high α-subunit and absence of...
A 31-year-old gentleman presented with clinical hyperthyroidism, goiter, bitemporal hemianopia, and discordant thyroid function test. The high α-subunit and absence of throtropin (thyroid-stimulating hormone; TSH) response to thyrotropin-releasing hormone stimulation indicated a TSH-secreting pituitary tumor. Elevation in prolactin and growth hormone as well as secondary hypogonadism were also observed. A sellar-suprasellar mass displacing the optic chiasm was revealed upon magnetic resonance imaging. The patient was rendered euthyroid with carbimazole and Lugol's iodine before undergoing endoscopic transsphenoidal surgery. Due to the incomplete tumor excision during surgery, patient experienced recurrence of symptoms and rising thyroxine (T4) with nonsuppressed TSH. The histopathology examination demonstrated a plurihormonal tumor with positive immunohistochemical stain for TSH, growth hormone, and prolactin, with invasive and proliferative features. Subsequently he was initiated with a long-acting somatostatin analogue and underwent stereotactic radiosurgery. To date, his symptoms have improved, with a reduction of insulin-like growth factor 1 and normalization of other pituitary hormones as well as a slightly reduced size of the pituitary tumor.
PubMed: 37908485
DOI: 10.1210/jcemcr/luad016 -
JCEM Case Reports Jan 2023Pituitary hyperplasia occurs as a result of an increase in pituitary cell subtypes. It can be a consequence of either a physiological or pathological condition. In our...
Pituitary hyperplasia occurs as a result of an increase in pituitary cell subtypes. It can be a consequence of either a physiological or pathological condition. In our case, a 31-year-old pregnant woman at 16 weeks gestation presented with headaches and vision changes. Visual field testing demonstrated bitemporal hemianopsia, and magnetic resonance imaging (MRI) brain showed enlargement of the pituitary with compression of the optic chiasm. She was treated with cabergoline and steroids, and her symptoms improved. In a subsequent pregnancy, the patient developed similar symptoms, and with cabergoline treatment, her symptoms resolved. A postpartum MRI of her brain revealed a decrease in pituitary size back to baseline with normal pituitary hormone levels. This patient's likely diagnosis was physiologic pituitary hyperplasia. Pituitary hyperplasia can be difficult to diagnose since there are no explicit guidelines. Through deduction of imaging findings and hormonal levels, diagnosis of pituitary hyperplasia becomes a more manageable task.
PubMed: 37908281
DOI: 10.1210/jcemcr/luad003