Publications by authors named "Vahid Mohammadzadeh"

21 Publications

  • Page 1 of 1

Estimating the Severity of Visual Field Damage From Retinal Nerve Fiber Layer Thickness Measurements With Artificial Intelligence.

Transl Vis Sci Technol 2021 Aug;10(9):16

Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN, USA.

Purpose: The purpose of this study was to assess the accuracy of artificial neural networks (ANN) in estimating the severity of mean deviation (MD) from peripapillary retinal nerve fiber layer (RNFL) thickness measurements derived from optical coherence tomography (OCT).

Methods: Models were trained using 1796 pairs of visual field and OCT measurements from 1796 eyes to estimate visual field MD from RNFL data. Multivariable linear regression, random forest regressor, support vector regressor, and 1D convolutional neural network (CNN) models with sectoral RNFL thickness measurements were examined. Three independent subsets consisting of 698, 256, and 691 pairs of visual field and OCT measurements were used to validate the models. Estimation errors were visualized to assess model performance subjectively. Mean absolute error (MAE), root mean square error (RMSE), median absolute error, Pearson correlation, and R-squared metrics were used to assess model performance objectively.

Results: The MAE and RMSE of the ANN model based on the testing dataset were 4.0 dB (95% confidence interval = 3.8-4.2) and 5.2 dB (95% confidence interval = 5.1-5.4), respectively. The ranges of MAE and RMSE of the ANN model on independent datasets were 3.3-5.9 dB and 4.4-8.4 dB, respectively.

Conclusions: The proposed ANN model estimated MD from RNFL measurements better than multivariable linear regression model, random forest, support vector regressor, and 1-D CNN models. The model was generalizable to independent data from different centers and varying races.

Translational Relevance: Successful development of ANN models may assist clinicians in assessing visual function in glaucoma based on objective OCT measures with less dependence on subjective visual field tests.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1167/tvst.10.9.16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8375007PMC
August 2021

Detection of Longitudinal Ganglion Cell/Inner Plexiform Layer Change: Comparison of Two Spectral-Domain Optical Coherence Tomography Devices.

Am J Ophthalmol 2021 Jun 5;231:1-10. Epub 2021 Jun 5.

From the Glaucoma Division (G.M., V.M., S.H.Z., E.M., J.M., S.K.L., A.L.C., J.C., K.N-M.), Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California. Electronic address:

Purpose: We compared rates of change of macular ganglion cell/inner plexiform (GCIPL) thickness and proportion of worsening and improving rates from 2 optical coherence tomography (OCT) devices in a cohort of eyes with glaucoma.

Design: Longitudinal cohort study.

Methods: In a tertiary glaucoma clinic we evaluated 68 glaucoma eyes with ≥2 years of follow-up and ≥4 OCT images. Macular volume scans from 2 OCT devices were exported, coregistered, and segmented. Global and sectoral GCIPL data from the central 4.8 × 4.0-mm region were extracted. GCIPL rates of change were estimated with linear regression. Permutation analyses were used to control specificity with the 2.5 percentile cutoff point used to define "true" worsening. Main outcome measures included differences in global/sectoral GCIPL rates of change between 2 OCT devices and the proportion of negative vs positive rates of change (P < .05).

Results: Average (standard deviation) 24-2 visual field mean deviation, median (interquartile range) follow-up time, and number of OCT images were -9.4 (6.1) dB, 3.8 (3.3-4.2) years, and 6 (5-8), respectively. GCIPL rates of thinning from Spectralis OCT were faster (more negative) compared with Cirrus OCT; differences were significant in superonasal (P = .03) and superotemporal (P = .04) sectors. A higher proportion of significant negative rates was observed with Spectralis OCT both globally and in inferotemporal/superotemporal sectors (P < .04). Permutation analyses confirmed the higher proportion of global and sectoral negative rates of change with Spectralis OCT (P < .001).

Conclusions: Changes in macular GCIPL were detected more frequently on Spectralis' longitudinal volume scans than those of Cirrus OCT. OCT devices are not interchangeable with regard to detection of macular structural progression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajo.2021.05.016DOI Listing
June 2021

Estimating Ganglion Cell Complex Rates of Change With Bayesian Hierarchical Models.

Transl Vis Sci Technol 2021 04;10(4):15

Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.

Purpose: Develop a hierarchical longitudinal regression model for estimating local rates of change of macular ganglion cell complex (GCC) measurements with optical coherence tomography (OCT).

Methods: We enrolled 112 eyes with four or more macular OCT images and ≥2 years of follow-up. GCC thickness measurements within central 6 × 6 superpixels were extracted from macular volume scans. We fit data from each superpixel separately with several hierarchical Bayesian random-effects models. Models were compared with the Watanabe-Akaike information criterion. For our preferred model, we estimated population and individual slopes and intercepts (baseline thickness) and their correlation.

Results: Mean (SD) follow-up time and median (interquartile range) baseline 24-2 visual field mean deviation were 3.6 (0.4) years and -6.8 (-12.2 to -4.3) dB, respectively. The random intercepts and slopes model with random residual variance was the preferred model. While more individual and population negative slopes were observed in the paracentral and papillomacular superpixels, superpixels in the superotemporal and inferior regions displayed the highest correlation between baseline thickness and rates of change (r = -0.43 to -0.50 for the top five correlations).

Conclusions: A Bayesian linear hierarchical model with random intercepts/slopes and random variances is an optimal initial model for estimating GCC slopes at population and individual levels. This novel model is an efficient method for estimating macular rates of change and probability of glaucoma progression locally.

Translational Relevance: The proposed Bayesian hierarchical model can be applied to various macular outcomes from different OCT devices and to superpixels of variable sizes to estimate local rates of change and progression probability.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1167/tvst.10.4.15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8054624PMC
April 2021

Prediction of Visual Field Progression from OCT Structural Measures in Moderate to Advanced Glaucoma.

Am J Ophthalmol 2021 06 30;226:172-181. Epub 2021 Jan 30.

Departments of Ophthalmology and Genetics, Genomics, and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee, USA.

Purpose: To test the hypothesis that visual field (VF) progression can be predicted from baseline and longitudinal optical coherence tomography (OCT) structural measurements.

Design: Prospective cohort study.

Methods: A total of 104 eyes (104 patients) with ≥3 years of follow-up and ≥5 VF examinations were enrolled. We defined VF progression based on pointwise linear regression on 24-2 VF (≥3 locations with slope less than or equal to -1.0 dB/year and P < .01). We used elastic net logistic regression (ENR) and machine learning to predict VF progression with demographics, baseline circumpapillary retinal nerve fiber layer (RNFL), macular ganglion cell/inner plexiform layer (GCIPL) thickness, and RNFL and GCIPL change rates at central 24 superpixels and 3 eccentricities, 3.4°, 5.5°, and 6.8°, from fovea and hemimaculas. Areas-under-ROC curves (AUC) were used to compare models.

Results: Average ± SD follow-up and VF examinations were 4.5 ± 0.9 years and 8.7 ± 1.6, respectively. VF progression was detected in 23 eyes (22%). ENR selected rates of change of superotemporal RNFL sector and GCIPL change rates in 5 central superpixels and at 3.4° and 5.6° eccentricities as the best predictor subset (AUC = 0.79 ± 0.12). Best machine learning predictors consisted of baseline superior hemimacular GCIPL thickness and GCIPL change rates at 3.4° eccentricity and 3 central superpixels (AUC = 0.81 ± 0.10). Models using GCIPL-only structural variables performed better than RNFL-only models.

Conclusions: VF progression can be predicted with clinically relevant accuracy from baseline and longitudinal structural data. Further refinement of proposed models would assist clinicians with timely prediction of functional glaucoma progression and clinical decision making.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajo.2021.01.023DOI Listing
June 2021

Local Macular Thickness Relationships between 2 OCT Devices.

Ophthalmol Glaucoma 2021 Mar-Apr;4(2):209-215. Epub 2020 Aug 29.

Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California. Electronic address:

Purpose: To compare local ganglion cell-inner plexiform layer (GCIPL) thickness measurements between 2 OCT devices and to explore factors that may influence the difference in measurements.

Design: Cross-sectional study.

Participants: Sixty-nine glaucoma eyes (63 patients) with evidence of central damage or mean deviation (MD) of -6.0 dB or worse on a 24-2 visual field (VF).

Methods: Cirrus and Spectralis OCT macular volume scans were exported, data from the central 20° of both OCT devices were centered and aligned, and 50 × 50 arrays of 0.4° × 0.4° superpixels were created. We estimated nonparametric (Spearman's) correlations and used Bland-Altman plots to compare GCIPL thickness measurements between the two OCTs at the superpixel level. Factors that may have influenced the differences between thickness measurements between the two devices were explored with linear mixed models.

Main Outcome Measures: Pooled and individual-eye Spearman's correlation and agreement between thickness measurements from the two devices.

Results: The median 24-2 VF MD was -6.8 dB (interquartile range [IQR], -4.9 to -12.3 dB). The overall pooled Spearman's correlation between the two devices for all superpixels and eyes was 0.97 (P < 0.001). The median within-eye correlation coefficient was 0.72 (IQR, 0.59-0.79). Bland-Altman plots demonstrated a systematic bias in most individual eyes, with Spectralis GCIPL measurements becoming larger than Cirrus measurements with increasing superpixel thickness. The average superpixel thickness and distance to the fovea influenced the thickness difference between the two devices in multivariate models (P < 0.001).

Conclusions: Local macular thickness measurements from the Spectralis and Cirrus devices are highly correlated, but not interchangeable. Differences in thickness measurements between the two devices are influenced by the location of superpixels and their thickness.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ogla.2020.08.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7914265PMC
August 2020

Comparison of Rates of Progression of Macular OCT Measures in Glaucoma.

Transl Vis Sci Technol 2020 06 30;9(7):50. Epub 2020 Jun 30.

Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.

Purpose: The purpose of this study was to compare rates of change of various macular thickness measures and evaluate the influence of baseline damage on macular rates of change.

Methods: One hundred twelve eyes (112 patients) with ≥ 2 years of follow-up and ≥ 5 macular optical coherence tomography (OCT) images and 10-2 visual field (VF) tests were included. OCT measures of interests were full macular thickness (FMT), ganglion cell complex (GCC), ganglion cell/inner plexiform layer (GCIPL), ganglion cell layer (GCL), and outer retinal layer (ORL) thickness in 3° × 3° superpixels. Rates of change were estimated with linear regression and normalized by dividing rates by the average normative superpixel thickness. We compared rates of change and proportion of significantly worsening superpixels (detection rate) and improving superpixels (false discovery rate [FDR]) among macular measures as a function of baseline thickness and 10-2 VF status.

Results: Median (interquartile range [IQR]) baseline VF mean deviation, follow-up time, and number of VFs/OCTs were -7.6 dB (-11.8 to -3.8 dB), 4.5 years (4.0-5.0 years), and 9 (8-10), respectively. Normalized FMT and GCC rates of change were faster and detection rates were higher than GCIPL and GCL ( < 0.001), but FMT had lower FDR than GCC ( = 0.02); faster FMT rates were partially explained by ORL rates of change. GCC detection rates were less likely than GCIPL and GCL rates to decrease with diminishing baseline thickness or worse VF damage. In eyes with 10-2 VF worsening, GCC and GCL demonstrated the fastest rates of change.

Conclusions: GCC measurements are most likely to detect structural worsening along the spectrum of glaucoma severity. Although FMT rates of change are least influenced by baseline thickness, they partially reflect likely age-related ORL changes.

Translational Relevance: GCC thickness measurements seem to be the optimal macular outcome measure for detection of glaucoma deterioration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1167/tvst.9.7.50DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7414740PMC
June 2020

The Trajectory of Glaucoma Progression in 2-Dimensional Structural-Functional Space.

Ophthalmol Glaucoma 2020 Nov - Dec;3(6):466-474. Epub 2020 Jun 9.

Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California. Electronic address:

Purpose: To present a method that allows visualization of functional and structural change in 2-dimensional space.

Design: Retrospective, longitudinal, observational study.

Participants: Patients from the Stein Eye Institute, UCLA from 1993 through 2017.

Methods: Patients were arranged into 2 cohorts. Cohort 1 was used to create a structural score for the horizontal axis of the structural-functional (S-F) 2-dimensional space. The visual field (VF) index was used for the vertical axis as the functional score. Cohort 2 was used to apply those scores for analysis of S-F progression with a combined vector. The first cohort included eyes with mild glaucoma (abnormal glaucoma hemifield test results, pattern standard deviation <0.05 on 2 examinations, or mean deviation [MD] >-5 dB) and normal control participants. The second cohort included all stages of open-angle glaucoma with ≥5 OCT retinal nerve fiber layer scans, ≥5 reliable visual field (VF) results, and follow-up of ≥4 years.

Main Outcome Measures: Vectors were created for each eye to represent the trajectory of glaucoma progression over time. Each vector was defined by structural (x-axis) and functional (y-axis) components. The structural component was calculated with a linear model of Heidelberg Retina Tomograph (Heidelberg Engineering, Heidelberg, Germany) scores over time. The functional component was calculated with a linear model of VF measurements over time. The resultant vector and its confidence interval were plotted in 2-dimensional S-F space. Eyes were divided into severity stages based on baseline MD. A mean vector was calculated for each severity stage.

Results: We obtained 290 vectors from 290 eyes of 196 patients. The mean ± standard deviation follow-up period was 14.6±3.1 years. Average age was 58.6±8.8 years. Preperimetric, mild, moderate, and severe categories included 41, 89, 97, and 63 eyes, respectively. Mean baseline MDs were 0.8 dB, -0.95 dB, -3.57 dB, and -11.51 dB, respectively, and mean vector slopes for each severity categories were 0.79, 0.95, 1.95, and 2.08, respectively. Cook's distance removed 131 (7.1%) and 137 (7.4%) outliers from the structure and function regressions, respectively.

Conclusions: We report a method to visualize the trajectory of a patient's glaucoma progression in a 2-dimensional S-F space. The slope of the trajectory of glaucoma progression is a function of the severity of the disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ogla.2020.06.003DOI Listing
September 2021

Multiple Evanescent White Dot Syndrome: A Case Report and Experience with Corticosteroid Therapy.

Iran J Allergy Asthma Immunol 2020 May 17;19(S1):91-94. Epub 2020 May 17.

Eye Research Center, Farabi Hospital, Tehran University of Medical Sciences, Tehran, Iran AND Department of Retina, Farabi Hospital, Tehran University of Medical Sciences, Tehran, Iran.

Multiple evanescent white dot syndrome (MEWDS) is an inflammatory eye disease of the outer retina, retinal pigmented epithelium, choroid presenting with photopsia, loss of vision, and temporal scotoma. The patient was a 31-year-old female with a history of vision loss since 11 days ago (left eye). At presentation, best-corrected Snellen visual acuity was 20/140 in the Snellen chart. We decided to treat her with short time corticosteroid therapy (0.75 mg/kg/day prednisolone which was tapered in 3 weeks) for any possible rapid recovery of vision. The visual acuity of the involved eye was improved to 20/25 and 20/20, one week and three weeks after starting treatment respectively. Thus, it seems that short-term oral steroids might be an alternative method of management for patients with MEWDS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18502/ijaai.v19i(s1.r1).2865DOI Listing
May 2020

Macular imaging with optical coherence tomography in glaucoma.

Surv Ophthalmol 2020 Nov - Dec;65(6):597-638. Epub 2020 Mar 19.

Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, USA. Electronic address:

With the advent of spectral-domain optical coherence tomography, imaging of the posterior segment of the eye can be carried out rapidly at multiple anatomical locations, including the optic nerve head, circumpapillary retinal nerve fiber layer, and macula. There is now ample evidence to support the role of spectral-domain optical coherence tomography imaging of the macula for detection of early glaucoma. Macular spectral-domain optical coherence tomography measurements demonstrate high reproducibility, and evidence on its utility for detection of glaucoma progression is accumulating. We present a comprehensive review of macular spectral-domain optical coherence tomography imaging emerging as an essential diagnostic tool in glaucoma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.survophthal.2020.03.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7423773PMC
July 2021

Longitudinal Macular Structure-Function Relationships in Glaucoma.

Ophthalmology 2020 07 22;127(7):888-900. Epub 2020 Jan 22.

Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California. Electronic address:

Purpose: To investigate the relationship between longitudinal changes in macular thickness measurements from OCT and changes in central visual field (VF) in patients with glaucoma with central or advanced damage at baseline.

Design: Longitudinal cohort study.

Participants: A total of 116 eyes with ≥3 years of follow-up and ≥5 macular OCT images and central 10° VF tests were selected.

Methods: OCT superpixels and VF locations were matched correcting for retinal ganglion cell (RGC) displacement. Superpixel thickness and VF total deviation (TD) values, in both logarithmic and linear scales, were averaged within 3 eccentricities (3.4°, 5.6°, and 6.8°) and superior and inferior hemiretinas and hemifields. We estimated pointwise TD rates of change and rates of change at superpixels for full macular thickness (FMT), ganglion cell complex (GCC), ganglion cell inner plexiform layer (GCIPL), and ganglion cell layer (GCL). Correlation of structure-function (SF) rates of change was investigated with parametric tests. We compared the proportion of worsening and positive slopes for superpixels and VF test locations (negative vs. positive rates of change with P < 0.05) throughout the follow-up period. Permutation analyses were used to control specificity.

Main Outcome Measures: Magnitude of correlation between structural and functional rates of change and proportion of worsening and positive slopes as a function of follow-up time.

Results: The median (interquartile range) follow-up and number of exams were 4.2 (3.7-4.6) years and 8 (7-9), respectively. The highest correlation of change rates was observed at 3.4° and 5.6° eccentricities (r = 0.24, 0.41, 0.40, and 0.40 for FMT, GCC, GCIPL, and GCL for 3.4° eccentricity and r = 0.28, 0.32, 0.31, and 0.32 for FMT, GCC, GCIPL, and GCL for 5.6° eccentricity, respectively). Although GCC measures demonstrated the highest overall longitudinal SF correlations, the differences were not statistically significant. Significant structural worsening was more frequently detected than functional deterioration at 3- and 5-year time points (P < 0.025). Permutation analyses also confirmed this finding.

Conclusions: Correlations between central structural and functional rates of change were weak to fair in this cohort. Structural changes were detected more frequently than functional changes. Measurements of both structure and function are required for optimal detection of central progression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ophtha.2020.01.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7311272PMC
July 2020

Oral Mineralocorticoid-Receptor Antagonists: Choroidal Parameters Changes Using OCT in Central Serous Chorioretinopathy.

Ophthalmic Surg Lasers Imaging Retina 2019 11;50(11):726-733

Background And Objective: To evaluate the efficacy and safety of oral eplerenone in the treatment of acute and chronic central serous chorioretinopathy (CSCR).

Patients And Methods: Treatment-naïve patients with acute (< 3 months) and chronic (≥ 3 months) CSCR were enrolled in this prospective, nonrandomized, interventional, comparative case series. Patients with acute CSCR were either treated with oral eplerenone (acute case group; n = 16) or observed only (acute control group; n = 8). All chronic patients (chronic group; n = 25) were treated with oral eplerenone. Eplerenone was prescribed 25 mg twice per day for 3 months. Best-corrected visual acuity (BCVA) and optical coherence tomography measures, including subretinal fluid (SRF) height, subfoveal choroidal thickness (CT), central CT, central choroidal volume (CV), and total CV, were assessed at baseline and 3-month follow-up (FU) visit.

Results: BCVA improvement and SRF reduction at 3-month FU relative to baseline were observed in all three study groups. SRF was completely resolved in 13 patients (81.2%) in the acute case group, four patients (50%) in the acute control group, and eight patients (32%) in the chronic group. The acute case group showed greater SRF decrease relative to baseline compared to the chronic group (P = .009), but the resolution of SRF between acute cases and an acute control group was not statistically significant (P = .076). Subfoveal CT, central CT, total CV, and central CV were significantly reduced at the 3-month FU compared to baseline in both affected and the fellow eyes in the acute case and chronic groups, whereas no change was observed in either eyes in the acute control group. At 3 months' FU, the mean logMAR visual acuity demonstrated no significant difference among the study groups (P = .08). Eplerenone was well-tolerated, and no serious side effect was detected.

Conclusions: Oral eplerenone is a safe and effective treatment option for both acute and chronic CSCR. Resolution of SRF was more significant in acute CSR cases comparative to chronic cases. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:726-733.].
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3928/23258160-20191031-08DOI Listing
November 2019

Ocular movement disorders following scleral buckling surgery: A case series study.

J Curr Ophthalmol 2019 Jun 7;31(2):195-200. Epub 2018 Oct 7.

Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.

Purpose: To evaluate ocular movement disorders after scleral buckling surgery (SBS) for retinal detachment.

Methods: In this prospective, observational, case series, 206 patients (206 eyes) with rhegmatogenous retinal detachment who underwent SBS and investigated at the strabismus ward of Farabi Eye Hospital in Iran between November 2011 and November 2014 were assessed. Patients were followed from 6 to 36 months after SBS to evaluate for strabismus. Logistic regression analysis test and SPSS software version 20 were used for statistical analysis.

Results: From 206 patients, 56.8% were male, and 33.2% were female. For scleral buckle in 44.7% of patients, silicone band and tire (SBT) was used, and in 55.3%, a sponge. Among all patients, seven (3.39%) exhibited ocular movement disorder. There was no significant relation between type of buckle ( = 0.65) or the location of buckle ( = 0.56) and movement disorder.

Conclusion: Ocular movement disorder is one of the main complications after SBS without specific association between the type and location of exoplanet.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.joco.2018.09.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6611860PMC
June 2019

Vision Loss After Glaucoma Surgery: Progressive Macular Thinning as a Sign of Snuff-Out Phenomenon.

J Glaucoma 2019 06;28(6):e99-e102

Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA.

We herein report 2 eyes with significant loss of vision after glaucoma filtering surgery that was accompanied by progressive macular thinning detected on macular optical coherence tomography imaging. The findings provide evidence that progressive retinal ganglion cell loss is one of the causes of visual loss after uncomplicated glaucoma surgery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/IJG.0000000000001202DOI Listing
June 2019

Assessing the Relation of Epicardial Fat Thickness and Volume, Quantified by 256-Slice Computed Tomography Scan, With Coronary Artery Disease and Cardiovascular Risk Factors.

Arch Iran Med 2018 03 1;21(3):95-100. Epub 2018 Mar 1.

Department of Radiology, Shaheed Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.

Background: This study aimed to investigate the association between epicardial adipose tissue (EAT) and coronary artery disease (CAD) as well as cardiovascular risk factors.

Methods: Complete medical records of subjects were reviewed and cardiovascular risk factors were recorded. Epicardial fat volume (EFV) and epicardial fat thickness (EFT) were measured using digital volumetry of acquired images using a 256-slice CT-scanner. Calcium score was measured using Agatston method in non-contrast images. After contrast administration, bolus-tract images were obtained. Coronary arteries were assessed using reconstructed images in arterial phase of contrast-enhanced images. EFV and EFT measurements were compared to computed tomography angiography (CTA) findings of coronary arteries.

Results: A total of 269 patients (Mean age: 55.5 ± 12.1, 44% female) were included. Higher means of EFT and EFV were associated with coronary artery stenosis. However, the correlation coefficients of the arterial stenosis with EFT and EFV were weak. EFV and EFT had a significant association with age (P < 0.001, P < 0.001 respectively), body mass index (BMI) (P < 0.001, P < 0.001 respectively) and hypertension (P < 0.016, P < 0.003 respectively). Diabetes mellitus (DM) and hyperlipidemia were not significantly associated with EFV (P = 0.069 and 0.639 respectively) and EFT (P = 0.103 and 0.366 respectively). EFV and EFT showed a weak correlation coefficient with calcium scoring (Spearman correlation coefficients: 0.26 and 0.22 respectively, both P < 0.001). In multivariate logistic regression models considering coronary stenosis as dependent variable and EFV, EFT and other CAD risk factors as independent variables, EFV and EFT did not show significant P values and were omitted from the model by other CAD risk factors.

Conclusion: Increased EFV and EFT are associated with CAD, age, BMI and hypertension. However, no remarkable association was found between them and calcium score, hyperlipidemia or DM. These variables could weakly predict CAD in univariate models but they are not independent predictive factors for CAD in multivariate models consisting of other CAD risk factors. Hence, EFT and EFV are not independent predictors for CADs when they are considered simultaneously with other CAD risk factors.
View Article and Find Full Text PDF

Download full-text PDF

Source
March 2018

Topographic typology in a consecutive series of refractive surgery candidates.

Int Ophthalmol 2018 Aug 4;38(4):1611-1619. Epub 2017 Jul 4.

Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Qazvin Square, P.O. Box 1336616351, Tehran, Iran.

Purpose: The term 'keratoconus (KC) suspect' is used as a blanket term to refer to any deviation of virgin cornea shape toward KC features. We intend to subclassify such topographies in meaningful and informative designations.

Methods: Pentacam corneal topographies of 199 consecutive refractive surgery candidates (398 eyes) are examined. Features of steepness, inferior-superior asymmetry, focal steepening, thinning, and bounded anterior or posterior elevations are observed in the quad map. Scissoring on retinoscopy, loss of best spectacle-corrected visual acuity, and iron ring deposition were looked for. Through iterative observation and refinement of classification criteria-partly taken from the literature-all eyes were designated a specific topographic diagnosis, i.e., circumventing the usage of the expression KC 'suspect'.

Results: Topographies of 308, 48, 21, 13, 6, 1, and 1 (collectively 398 eyes) were designated: normal, 'atypical normal,' forme fruste KC, posterior KC, subclinical/mild KC, superior KC, and pseudo-KC, respectively.

Conclusion: Current imaging modalities of the cornea and our accumulated experience in refractive science allow assignment of distinctive designations for abnormal corneal shapes along the topography spectrum. We devised and used the expressions: normal, atypical normal, forme fruste (arrested-incomplete) KC, posterior KC, subclinical (active latent) KC, superior KC, and pseudo-keratoconus. Identification of 1.5% (mild) KC highlights the importance of screening for ultraviolet cross-linkage candidacy in refractive surgery referrals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10792-017-0631-2DOI Listing
August 2018

Diagnostic Efficacy of Coronary Artery Three-Dimensional Steady-State Free Precession Magnetic Resonance Angiography in Comparison with Invasive Coronary Angiography for Detecting Coronary Artery Disease.

Arch Iran Med 2017 May;20(5):314-319

Amiralam Hospital, Tehran University of Medical Sciences, Tehran, Iran.

Purpose: To assess the diagnostic value of three-dimensional steady-state free precession magnetic resonance angiography (3D-SSFP MRA) for detecting coronary artery disease (CAD).

Materials And Methods: Patients suspected of CAD based on clinical evaluation, underwent invasive coronary angiography (CAG) and Cardiac MRA (CMRA). Collected data in favor of any CAD findings in CMRA were compared to CAG results as the standard diagnostic method in CAD detection. Analysis was performed on per-patient, per-vessel and per-segment bases.

Results: A total of 30 patients (mean age: 43 ± 10 years, 19 men) were enrolled for analysis. On per-patient analysis, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under receiver operator characteristic (ROC) curve of CMRA for detection of coronary artery stenosis were 100% (CI95%: 75% - 100%), 50% (CI95%: 18% - 81%), 73.33% (CI95%: 46% - 90%), 100% (CI95%: 47% - 100%) and 0.827, respectively. On per-vessel analysis, CMRA had a sensitivity of 89.29% (CI95%: 71%-97%), specificity of 80.56% (CI95%: 63% - 91%), PPV of 78.13% (CI95%: 60% - 90%), NPV of 90.63% (CI95%: 74% - 98%) and area under ROC curve of 0.845. On per-segment analysis, sensitivity, specificity, PPV and NPV of CMRA for segmental stenosis detection were 77.78% (CI95%: 60% - 89%), 87% (CI95%: 81% - 92%), 62% (CI95%: 46% - 76%), and 93.89% (CI95%:  88% - 97%), respectively. Area under ROC curve was 0.835 on per-segment analysis.

Conclusion: 3D SSFP CMRA provides a promising non-invasive diagnostic tool for assessing coronary artery disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/0172005/AIM.0010DOI Listing
May 2017

Pretreatment Evaluation of Glioma.

Neuroimaging Clin N Am 2016 Nov 3;26(4):567-580. Epub 2016 Sep 3.

Division of Neuroradiology, Department of Radiology, Amiralam Hospital, Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

Glioma is considered the most common type of primary central nervous system (CNS) tumor. Imaging is crucial for diagnosis, characterization, grading, and therapeutic planning of CNS gliomas. Along with a brief description of conventional computed tomography and magnetic resonance imaging techniques, this article reviews the ever-developing role of modern imaging techniques in preoperative management of CNS gliomas. It discusses current clinical applications, promising features, and limitations of each imaging method.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nic.2016.06.006DOI Listing
November 2016

Generalized lymphadenopathy in infancy; a case report.

Iran J Pediatr 2013 Feb;23(1):105-8

Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran ; Department of Pediatrics, Tehran University of Medical Sciences, Tehran, Iran.

Background: Rosai-Dorfman disease (RDD) is a rare disease of histiocytic cells, a cause of benign cervical lymphadenopathy (LAP) and massive generalized lymph node enlargement in children and adults. There are also some reports on involvement of other human body organs with or without LAP.

Case Presentation: A 7-month-old infant with chief complaint of generalized massive LAP was referred to our center. RDD was diagnosed according to clinical manifestations and confirmed through histopathologic and immunoreactivity study on the obtained sample by cervical lymph node biopsy.

Conclusion: RDD is not a malignant illness and lymph node enlargement most often decreases in its size happens without special treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3575001PMC
February 2013

Efficacy of transarterial chemoembolization on lesion reduction in colorectal liver metastases.

Acta Med Iran 2012 ;50(8):535-40

Department of Radiology, Advanced Diagnostic and Interventional Radiology Research Center, Medical Imaging Center, Imam Khomeini Hospital, Tehran University of medical Sciences, Tehran, Iran.

Following failure of systemic chemotherapy, transarterial chemoembolization (TACE) is an available method to control unresectable liver metastases from colorectal carcinoma (CRC). The aim of present study was to evaluate the efficacy of chemoembolization for inoperable metastatic liver lesions from CRC. Forty-five CRC patients with liver metastases resistant to systemic chemotherapy were enrolled in our study. For each patient, three session of TACE were conducted with 45 days interval. A combination of mitomycin, doxorubicin, and lipiodol were used for TACE. A tri-phasic computed tomography scan and biochemical laboratory tests were performed for all patients at baseline and 30 days after each TACE. Image analysis included measurement of lesion diameters as well as contrast enhancement. Eleven patients deceased before completing three session and the final analyses were performed on the remaining 34 patients. Evaluation of a total 93 lesions in all patients after chemoembolization sessions revealed a 25.88% reduction in anteroposterior (AP) diameter, 33.92% transverse (T) diameter, and 42.22% in product of APxT diameter of lesions (P<0.001 for all instances). CT scan showed a total disappearance of 33% of lesions and evident reduction in contrast enhancement in 16% of them. There were no changes in contrast enhancement in 51% of lesions. Evaluation of single largest lesion in each patient revealed 57.32% reduction in AP diameter, 59.66% in T diameter, and 62.17% in product of APxT diameters (P<0.001 for all diameters). TACE offers a viable option for CRC patients with unresectable liver metastases by significantly reducing lesion size and contrast enhancement.
View Article and Find Full Text PDF

Download full-text PDF

Source
April 2013

Diagnostic performance of multislice CT coronary angiography in the assessment of significant coronary artery disease.

Acta Med Iran 2012 ;50(1):31-6

Department of Radiology, Rejaee Cardiovascular Research Center, Tehran University of Medical Sciences, Iran.

The use of noninvasive assessment tools such as multi-slice CT coronary angiography (MSCT-CA-CA) is recently considered mainly because it offers safety, patient convenience, and faster performance. The aim of the present study was to determine the ability of MSCT-CA-CA for the detection of significant stenoses in the coronary arteries, in comparison to conventional invasive coronary angiography (ICA). A total of 58 consecutive patients who were candidate for coronary angiography, with the diagnosis of acute coronary syndrome, from September 2006 to March 2006 were entered into the study. They underwent both coronary MSCT-CA-CA and ICA. The findings of each coronary segment were compared to MSCT-CA-CA in comparison with ICA. Based on artery analysis, sensitivity and specificity of MSCT-CA for the detection of involvement in RCA were 90.0% and 92.8%, in LAD were 71.8% and 92.9% and in LCX were 67.9% and 92.6%, respectively. On a per-segment basis, the sensitivity of MSCT-CA in the detection of injured segments ranged between 33.3% (for segment 11) and 100% (for segments 1, 2 and 12). Also, specificity ranged from 63.6% (for segment 15) and 98.1% (for segment 6). The presence of hypertension, hyperlipidemia, and smoking led to the reduction of the specificity and accuracy of MSCT-CA, whereas history of diabetes mellitus could increase the specificity and accuracy of this tool. MSCT-CA has high diagnostic performance in the assessment of significant coronary artery disease. Risk factors for coronary artery disease may influence this performance.
View Article and Find Full Text PDF

Download full-text PDF

Source
May 2012

Arterial damage accompanying supracondylar fractures of the humerus.

Trauma Mon 2012 Jan 15;16(4):160-3. Epub 2012 Jan 15.

Gilan University of Medical Science, Rasht, IR Iran.

Background: Arterial damage is sometimes associated with supracondylar fractures of the humerus. Diagnosis and careful management of the fracture and arterial repair is crucial.

Objectives: The aim of this study was to determine the prevalence and outcome of supracondylar fractures of the humerus with signs and symptoms of limb ischemia, before and after arterial decompression or arterial reconstruction.

Materials And Methods: From September 2004 to July 2010, 225 consecutive patients with supracondylar fracture of the humerus were prospectively recruited.

Results: From among 75 cases with Gartland type III fractures, 22 were found to have vascular injury.. Of the 22 cases with vascular injury, 7 patients underwent arterial reconstruction. The other 15 received arterial decompression. All patients had a satisfactory outcome.

Conclusions: A high level of suspicion and careful clinical evaluation leading to an early diagnosis and management of vascular injury accompanying supracondylar fracture is very important to prevent unnecessary sequelae ranging from limb claudication, and compartment syndrome to more severe complications like Volkmann's contracture and even limb loss.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5812/kowsar.22517464.3273DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3989565PMC
January 2012
-->