8 results on '"Nicholas Hazen"'
Search Results
2. Virtual-Reality Effects on Acute Pain During Office Hysteroscopy: A Randomized Controlled Trial
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Elizabeth Brunn, Megan Cheney, Nicholas Hazen, Vadim Morozov, and James K. Robinson
- Subjects
Obstetrics and Gynecology ,Surgery - Published
- 2022
3. Regional variation of corneal stromal deformation measured by high-frequency ultrasound elastography
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Keyton Clayson, Sunny Kwok, Jun Liu, Xueliang Pan, and Nicholas Hazen
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Adult ,Male ,Keratoconus ,Intraocular pressure ,medicine.medical_specialty ,Stromal cell ,genetic structures ,Corneal Stroma ,Deformation (meteorology) ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,0302 clinical medicine ,Cornea ,Ophthalmology ,medicine ,Ultrasound elastography ,Humans ,Intraocular Pressure ,Aged ,Ultrasonography ,Original Research ,030304 developmental biology ,0303 health sciences ,medicine.diagnostic_test ,business.industry ,Middle Aged ,medicine.disease ,eye diseases ,Biomechanical Phenomena ,medicine.anatomical_structure ,030221 ophthalmology & optometry ,Elasticity Imaging Techniques ,Female ,sense organs ,Elastography ,business ,Algorithms ,High frequency ultrasound - Abstract
The cornea’s mechanical response to intraocular pressure elevations may alter in ectatic diseases such as keratoconus. Regional variations of mechanical deformation in normal and keratoconus eyes during intraocular pressure elevation have not been well-characterized. We applied a high-frequency ultrasound elastography technique to characterize the regional deformation of normal and keratoconus human corneas through the full thickness of corneal stroma. A cross-section centered at the corneal apex in 11 normal and 2 keratoconus human donor eyes was imaged with high-frequency ultrasound during whole globe inflation from 5 to 30 mmHg. An ultrasound speckle tracking algorithm was used to compute local tissue displacements. Radial, tangential, and shear strains were mapped across the imaged cross-section. Strains in the central (1 mm surrounding apex) and paracentral (1 to 4 mm from apex) regions were analyzed in both normal and keratoconus eyes. Additional regional analysis was performed in the eye with severe keratoconus presenting significant thinning and scarring. Our results showed that in normal corneas, the central region had significantly smaller tangential stretch than the paracentral region, and that within the central region, the magnitudes of radial and shear strains were significantly larger than that of tangential strain. The eye with mild keratoconus had similar shear strain but substantially larger radial strains than normal corneas, while the eye with severe keratoconus had similar overall strains as in normal eyes but marked regional heterogeneity and large strains in the cone region. These findings suggested regional variation of mechanical responses to intraocular pressure elevation in both normal and keratoconus corneas, and keratoconus appeared to be associated with mechanical weakening in the cone region, especially in resisting radial compression. Comprehensive characterization of radial, tangential, and shear strains through corneal stroma may provide new insights to understand the biomechanical alterations in keratoconus.
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- 2021
4. #MIGS: Minimally Invasive Gynecologic Surgery Tag Ontology Project
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Nicholas Hazen, M.D. Truong, Cheryl B. Iglesia, Abigail Davenport, Rosanne M. Kho, Elizabeth A Brunn, and Elizabeth Hoang
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medicine.medical_specialty ,030219 obstetrics & reproductive medicine ,business.industry ,Frequency of use ,Psychological intervention ,Obstetrics and Gynecology ,Disease ,Ontology (information science) ,Influencer marketing ,Surgery ,03 medical and health sciences ,0302 clinical medicine ,Gynecologic Surgical Procedures ,030220 oncology & carcinogenesis ,Medicine ,Humans ,Social media ,Female ,business - Abstract
Study Objective The creation of an ontology may enable providers to more definitively engage the public in evidence-based and meaningful discussions about women's health. The goal of this study is to review and analyze the current social media status of minimally invasive gynecologic surgery (MIGS) on Twitter and create a tag ontology. Design Tag ontologies are lists of hashtags used to standardize searches within a social media platform. We examined trending terms and influencers on Twitter on the basis of the keyword “MIGS.” We then compiled a list of top hashtags on the basis of the number of tweets from January 2018 to August 2020. Terms were identified with manual Twitter queries and Symplur Signals and selected for inclusion in the ontology on the basis of frequency of use and clinical relevance. The ontology was then categorized by pelvic disease and intervention and reviewed/supplemented by key social media influencers for inclusivity. Setting N/A Patients N/A Interventions N/A Measurements and Main Results We identified 4550 tweets and 1836 users while searching #MIGS in August 2020. Twenty-nine terms were included in our ontology, which were then subcategorized into 6 groups (uterine pathology, adnexal pathology, menstruation, pelvic pathology, pelvic pain, and other). Conclusion Our study has created an ontology specific to the MIGS on the basis of Twitter usage over the last 2 years that may facilitate more effective social media communication.
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- 2021
5. Venous Thromboembolism in Women with Uterine Fibroids
- Author
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Valentina Baez Sosa, Kelly W. Fitzpatrick, Saira Farid, Stephen Fernandez, Hira Latif, Nicholas Hazen, and Vadim Morozov
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education.field_of_study ,medicine.medical_specialty ,Uterine fibroids ,Obstetrics ,business.industry ,Deep vein ,Incidence (epidemiology) ,Immunology ,Population ,Warfarin ,Cell Biology ,Hematology ,medicine.disease ,Biochemistry ,Inferior vena cava ,Pulmonary embolism ,medicine.anatomical_structure ,medicine.vein ,medicine ,cardiovascular diseases ,Prospective cohort study ,education ,business ,medicine.drug - Abstract
Background:Uterine fibroids, also called leiomyomas, are diagnosed in over two-third of females of reproductive age; about a quarter warrant treatment. Venous thromboembolism (VTE) is a challenging complication in patients with fibroids due to the increased risk of bleeding with anticoagulation, especially in the setting of associated menorrhagia. The incidence of deep vein thrombosis (DVT) is increased with higher uterine weight which may be related to the extrinsic venous compression of the iliac veins or the inferior vena cava. However, there is reported discordance between the site of uterine fibroid and the site of the DVT along with pulmonary embolism (PE) without evidence of lower extremity DVT suggesting an underlying hypercoagulable state that is more complex than mere hormonal and mechanical factors. Data regarding VTE in patients with uterine fibroids in the US is sparse and is limited to case reports. We performed a retrospective case control study to describe the rate and associated risk factors of VTE in patients with uterine fibroids. Objectives:Evaluate the incidence of VTE events in patients with uterine fibroids and explore trends and associations. Methods:A retrospective chart review of patients at our single, academic, DC metropolitan hospital was conducted. Patients were identified using electronic medical records via ICD-10 codes. Those seen as an inpatient or outpatient in our tertiary care fibroid center with a new diagnosis of uterine fibroids between January 1, 2015, and December 31, 2019 were included and compared to age matched controls of patients with uterine fibroids without VTE in a 1:2 ratio. Statistical analysis was reported as means and medians for descriptive data. Pearson's correlation was performed to determine associations. Results:A total of 6095 patients were diagnosed with uterine fibroids in 5 years, of which 2.2% (n=139) were found to have VTE after the diagnosis of uterine fibroid was made (see table 1). Of the patients with VTE, 88 had DVTs,63 had PE and 12 developed both DVT and PE. The mean age at diagnosis of VTE was 54 (SD=14.95) years. The majority of the patients in the VTE group were African Americans (86%) and mean BMI was 34.52 (SD =9.53), of which about 2/3 were obese or morbidly obese. Average weight of fibroid(s) for those who underwent surgical resection who had available records was noted to be 321 grams (n=11). Data regarding anticoagulation was available for 78% of the patients; the anticoagulant of choice being enoxaparin in 59%, warfarin in 9% and DOACs in 10% of the patients. Two Hundred and thirty-six age matched controls were identified. Statistically significant associations with BMI, race and comorbidities (including atrial fibrillation, congestive heart failure, diabetes, hypertension, HIV, pregnancy and cancer) were found in cases when compared to the control population. Furthermore, cases were found to have a lower mean hemoglobin (10.4 mg/dL) and higher platelet count (311,000/microL) which were statistically significant (p=0.0003). The use of non-steroidal anti-inflammatory drugs and iron supplementation was significantly more in cases than controls. D-dimer and ferritin levels seemed to trend higher and iron saturation lower in cases than controls but were not found to be statistically significant. Conclusions:VTE was found in 2.2% of patients with uterine fibroids, which is higher than the reported VTE incidence of 1-2 per 1000 in the general population. A significant association was found with race, which is consistent with literature that suggests African American patients have a higher rate of incident VTE and also comorbid conditions. Women with low hemoglobin and higher platelet count were more likely to experience VTE. The next steps include understanding more associations, laboratory and clinical, that will assist in risk stratification and tailoring management. Future prospective studies to recognize biomarkers that contribute the hypercoagulable state of uterine fibroids is warranted. Disclosures Morozov: Medtronic:Consultancy;Lumenis:Speakers Bureau;AbbVie:Speakers Bureau.Fitzpatrick:Pfizer:Honoraria.
- Published
- 2020
6. Heartbeat-Induced Corneal Axial Displacement and Strain Measured by High Frequency Ultrasound Elastography in Human Volunteers
- Author
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Xueliang Pan, Nicholas Hazen, Andrew J Hendershot, Jun Liu, Yanhui Ma, Keyton Clayson, and Sunny Kwok
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elastography ,Intraocular pressure ,genetic structures ,Heartbeat ,Biomedical Engineering ,Article ,Cornea ,ocular pulse ,Tonometry, Ocular ,Speckle pattern ,Heart Rate ,medicine ,Humans ,corneal displacements ,high frequency ultrasound ,medicine.diagnostic_test ,business.industry ,Pulse (signal processing) ,Ultrasound ,Repeatability ,Healthy Volunteers ,eye diseases ,Ophthalmology ,medicine.anatomical_structure ,Elasticity Imaging Techniques ,sense organs ,Elastography ,corneal biomechanics ,business ,Biomedical engineering - Abstract
Purpose The purpose of this study was to establish in vivo data acquisition and processing protocols for repeatable measurements of heartbeat-induced corneal displacements and strains in human eyes, using a high-frequency ultrasound elastography method, termed ocular pulse elastography (OPE). Methods Twenty-four volunteers with no known ocular diseases were recruited for this study. Intraocular pressure (IOP) and ocular pulse amplitude (OPA) were measured using a PASCAL Dynamic Contour Tonometer (DCT). An in vivo OPE protocol was developed to measure heartbeat-induced corneal displacements. Videos of the central 5.7 mm of the cornea were acquired using a 50-MHz ultrasound probe at 128 frames per second. The radiofrequency data of 1000 frames were analyzed using an ultrasound speckle tracking algorithm to calculate corneal displacements and quantify spectral and temporal characteristics. The intrasession and intersession repeatability of OPE- and DCT-measured parameters were also analyzed. Results The in vivo OPE protocol and setup were successful in tracking heartbeat-induced corneal motion using high-frequency ultrasound. Corneal axial displacements showed a strong cardiac rhythm, with good intrasession and intersession repeatability, and high interocular symmetry. Corneal strain was calculated in two eyes of two subjects, showing substantially different responses. Conclusions We demonstrated the feasibility of high-frequency ultrasound elastography for noninvasive in vivo measurement of the cornea's biomechanical responses to the intrinsic ocular pulse. The high intrasession and intersession repeatability suggested a robust implementation of this technique to the in vivo setting. Translational relevance OPE may offer a useful tool for clinical biomechanical evaluation of the cornea by quantifying its response to the intrinsic pulsation.
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- 2020
7. IOP-induced regional displacements in the optic nerve head and correlation with peripapillary sclera thickness
- Author
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Elias Pavlatos, Nicholas Hazen, Yanhui Ma, Keyton Clayson, Jun Liu, Sunny Kwok, Jiajun Sun, and Xueliang Pan
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Adult ,Male ,0301 basic medicine ,Intraocular pressure ,Lamina ,medicine.medical_specialty ,Materials science ,genetic structures ,Finite Element Analysis ,Optic Disk ,Glaucoma ,Article ,Young Adult ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Speckle pattern ,0302 clinical medicine ,Ophthalmology ,medicine ,Humans ,heterocyclic compounds ,Intraocular Pressure ,Aged ,Ultrasonography ,business.industry ,Ultrasound ,Echogenicity ,Middle Aged ,medicine.disease ,eye diseases ,Sensory Systems ,Sclera ,Cross-Sectional Studies ,030104 developmental biology ,medicine.anatomical_structure ,030221 ophthalmology & optometry ,Optic nerve ,Female ,sense organs ,business ,Algorithms - Abstract
Mechanical insult induced by intraocular pressure (IOP) is likely a driving force in the disease process of glaucoma. This study aimed to evaluate regional displacements in human optic nerve head (ONH) and peripapillary tissue (PPT) in response to acute IOP elevations, and their correlations with morphological characteristics of the posterior eye. Cross-sectional (2D) images of the ONH and PPT in 14 globes of 14 human donors were acquired with high-frequency ultrasound during whole globe inflation from 5 to 30 mm Hg. High-frequency ultrasound has a spatial resolution of tens of micrometers and is capable of imaging through the ONH and PPT thickness. Tissue displacements were calculated using a correlation-based speckle tracking algorithm for a dense matrix of kernels covering the 2D imaging plane. The ONH was manually segmented in the ultrasound B-mode images acquired at 5 mmHg based on echogenicity. The lamina cribrosa (LC) boundaries were visible in eight of the fourteen eyes and the LC region was segmented using a semi-automated superpixel-based method. The ONH had larger radial displacement than the PPT in all tested eyes and the difference increased with increasing IOP. A significant negative correlation was found between ONH-PPT displacement difference and PPT thickness (p 0.05), while no significant correlations were found between ONH-PPT displacement difference and other morphological parameters including PPT radius of curvature, scleral canal size, LC thickness and anterior LC surface depth. Within the ONH, the radial displacement decreased in the region anterior to and across LC but not in the region posterior to LC. Finite element models using simplified geometry and material properties confirmed the role of LC in reducing the overall ONH radial displacements, but did not predict the displacement gradient change observed experimentally. These results suggested that a thinner PPT may be associated with a larger relative posterior motion of the ONH with respect to the surrounding PPT and the LC may play a major role in preventing excessive posterior displacement of ONH during acute IOP elevations.
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- 2020
8. Subspecialty Influence on Scientific Peer Review for an Obstetrics and Gynecology Journal With a High Impact Factor
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Rebecca S. Benner, Thomas W. Riggs, Nicholas Hazen, Laura I. Parikh, and Nancy C. Chescheir
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medicine.medical_specialty ,Reproductive endocrinology and infertility ,MEDLINE ,Gynecologic oncology ,Subspecialty ,03 medical and health sciences ,0302 clinical medicine ,Obstetrics and gynaecology ,medicine ,Humans ,030212 general & internal medicine ,Retrospective Studies ,Gynecology ,Observer Variation ,business.industry ,Obstetrics and Gynecology ,Retrospective cohort study ,Odds ratio ,Obstetrics ,Family medicine ,Medicine ,Journal Impact Factor ,business ,030217 neurology & neurosurgery - Abstract
OBJECTIVE To evaluate whether quality of peer review and reviewer recommendation differ based on reviewer subspecialty in obstetrics and gynecology and to determine the role of experience on reviewer recommendation. METHODS We performed a retrospective cohort study of reviews submitted to Obstetrics & Gynecology between January 2010 and December 2014. Subspecialties were determined based on classification terms selected by each reviewer and included all major obstetrics and gynecology subspecialties, general obstetrics and gynecology, and nonobstetrics and gynecology categories. Review quality (graded on a 5-point Likert scale by the journal's editors) and reviewer recommendation of "reject" were compared across subspecialties using χ, analysis of variance, and multivariate logistic regression. RESULTS There were 20,027 reviews from 1,889 individual reviewers. Reviewers with family planning subspecialty provided higher-quality peer reviews compared with reviewers with gynecology only, reproductive endocrinology and infertility, gynecologic oncology, and general obstetrics and gynecology specialties (3.61±0.75 compared with 3.44±0.78, 3.42±0.72, 3.35±0.75, and 3.32±0.81, respectively, P
- Published
- 2017
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