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Featured researches published by Vivek Patel.


Canadian Journal of Ophthalmology-journal Canadien D Ophtalmologie | 2014

Incidence of discordant temporal artery biopsy in the diagnosis of giant cell arteritis.

Bethany Durling; Andrew Toren; Vivek Patel; Steven Gilberg; Ezekiel Weis; David R. Jordan

OBJECTIVE We investigated the rate of discordant biopsy results (i.e., 1 side negative, 1 side positive) in patients who underwent initial bilateral temporal artery biopsies for suspected giant cell arteritis (GCA). DESIGN A cohort study. PARTICIPANTS Consecutive patients undergoing temporal artery biopsy were enrolled. Of the 259 patients enrolled, 250 underwent initial bilateral temporal artery biopsies. METHODS Positive biopsies were defined based on accepted histologic definitions. Healed arteritis was considered a positive result. Clinical information was collected for all patients using a questionnaire administered by an ophthalmologist. Pathology results, including biopsy length (as measured by the pathologist), and laboratory information (i.e., serum erythrocyte sedimentation rate [ESR] and C-reactive protein [CRP] levels) were collected from digital patient records for statistical analysis. The main outcome was the rate of discordant biopsy in consecutive patients who underwent initial bilateral temporal artery biopsy. RESULTS Giant cell arteritis was confirmed in 62 (24.2%) of the 250 patients, including 3 patients with biopsies recorded as healed arteritis. The rate of discordant biopsy was 4.4% with 11 unilaterally positive biopsies. There was no statistical difference between the length of the left- and right-sided biopsies in either the unilaterally or bilaterally positive groups (p = 0.13 and p = 0.79, respectively). The average maximum ESR value for the bilateral group (58.7 mm/h) was significantly higher than the average maximum ESR value for the unilateral group (30.7 mm/h, p = 0.03). The average maximum CRP value for the bilateral group was 59.2 mg/L and 28.6 mg/L for the unilateral group (p = 0.30). Discordance between the localization of symptoms and the side of positive biopsy occurred in 3 patients (i.e., 3 patients had left-sided symptoms only, yet a right-sided positive biopsy). CONCLUSIONS The rate of discordant biopsies in patients who underwent initial bilateral temporal artery biopsies was considerable in our patient cohort. Given this reasonably high rate of discordance between sides, as well as the lack of correlation between side of positivity and laterality of presenting symptoms, we recommend initial bilateral temporal artery biopsies to enhance the diagnostic certainty of the disease.


Clinical Ophthalmology | 2017

Multivariable prediction model for suspected giant cell arteritis: development and validation

Edsel Ing; Gabriela Lahaie Luna; Andrew Toren; Royce Ing; John J. Chen; Nitika Arora; Nurhan Torun; Otana A Jakpor; J Alexander Fraser; Felix Tyndel; Arun Sundaram; Xinyang Liu; Cindy Ty Lam; Vivek Patel; Ezekiel Weis; David R. Jordan; Steven Gilberg; Christian Pagnoux; Martin ten Hove

Purpose To develop and validate a diagnostic prediction model for patients with suspected giant cell arteritis (GCA). Methods A retrospective review of records of consecutive adult patients undergoing temporal artery biopsy (TABx) for suspected GCA was conducted at seven university centers. The pathologic diagnosis was considered the final diagnosis. The predictor variables were age, gender, new onset headache, clinical temporal artery abnormality, jaw claudication, ischemic vision loss (VL), diplopia, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and platelet level. Multiple imputation was performed for missing data. Logistic regression was used to compare our models with the non-histologic American College of Rheumatology (ACR) GCA classification criteria. Internal validation was performed with 10-fold cross validation and bootstrap techniques. External validation was performed by geographic site. Results There were 530 complete TABx records: 397 were negative and 133 positive for GCA. Age, jaw claudication, VL, platelets, and log CRP were statistically significant predictors of positive TABx, whereas ESR, gender, headache, and temporal artery abnormality were not. The parsimonious model had a cross-validated bootstrap area under the receiver operating characteristic curve (AUROC) of 0.810 (95% CI =0.766–0.854), geographic external validation AUROC’s in the range of 0.75–0.85, calibration pH–L of 0.812, sensitivity of 43.6%, and specificity of 95.2%, which outperformed the ACR criteria. Conclusion Our prediction rule with calculator and nomogram aids in the triage of patients with suspected GCA and may decrease the need for TABx in select low-score at-risk subjects. However, misclassification remains a concern.


Journal of Neuro-ophthalmology | 2015

High-Resolution 3D Magnetic Resonance Imaging of the Sixth Cranial Nerve: Anatomic and Pathologic Considerations by Segment.

Marinos Kontzialis; Asim F. Choudhri; Vivek Patel; Prem S. Subramanian; Masaru Ishii; Gary L. Gallia; Nafi Aygun; Ari M. Blitz

Background: Weakness of the sixth cranial nerve is the most common cause of an ocular motor cranial nerve palsy. It is often difficult to identify a corresponding abnormality on neuroimaging to correlate with the clinical examination. Evidence Acquisition: High-resolution 3D skull base magnetic resonance imaging (MRI) allows for visualization of the sixth nerve along much of its course and may increase sensitivity for abnormalities in regions that previously were challenging to evaluate. In this review, the authors share their experience with high-resolution imaging of the sixth nerve. Results: For each segment, anatomic features visible on high-resolution imaging are described along with relevant pathologic entities. Conclusions: We present a segmental approach to high-resolution 3D MRI for evaluation of the sixth nerve from the nuclear to the orbital segment.


Retinal Cases & Brief Reports | 2017

THE SECOND BLIND SPOT: SMALL RETINAL VESSEL VASCULOPATHY AFTER VACCINATION AGAINST NEISSERIA MENINGITIDIS AND YELLOW FEVER.

Stavros N. Moysidis; Nicole Koulisis; Vivek Patel; Amir H. Kashani; Narsing A. Rao; Mark S. Humayun; Damien C. Rodger

Purpose: To describe a case of small retinal vessel vasculopathy postvaccination. Methods: We report the case of a 41-year-old white man who presented with a “second blind spot,” describing a nasal scotoma in the right eye that started 4 days after vaccinations against Neisseria meningitidis and the yellow fever virus, and after a 2-month period of high stress and decreased sleep. Clinical examination, Humphrey visual field testing, and multimodal imaging with fundus photographs, autofluorescence, fluorescein angiography, and spectral domain optical coherence tomography and angiography were performed. Results: Clinical examination revealed a well-circumscribed, triangular area of retinal graying of about 1-disk diameter in size, located at the border of the temporal macula. This corresponded to a deep scotoma similar in size to the physiologic blind spot on Humphrey visual field 24-2 testing. There was mild hypoautofluoresence of this lesion on autofluorescence, hypofluorescence on fluorescein angiography, and focal attenuation of a small artery just distal to the bifurcation of an artery supplying the involved area. Spectral domain optical coherence tomography through the lesion conveyed hyperreflectivity most prominent in the inner and outer plexiform layers, with extension of the hyperreflectivity into the ganglion cell and inner nuclear layers. Spectral domain optical coherence tomography angiography demonstrated arteriolar and capillary dropout, more pronounced in the superficial retinal layer compared to the deeper retinal layer. At 1-month follow-up, his scotoma improved with monitoring, with reduction from −32 dB to −7 dB on Humphrey visual field testing. There was clinical resolution of the area of graying and decreased hyperreflectivity on spectral domain optical coherence tomography, with atrophy of the inner retina. Spectral domain optical coherence tomography angiography showed progression of arteriolar and capillary dropout, more so in the superficial than in the deep capillary plexus. Conclusion: We describe a case of small artery occlusion in a previously healthy patient, 4 days after vaccination against N. meningitidis and yellow fever. Fluorescein angiography yielded greater diagnostic value than OCTA for evaluating the occlusion, whereas spectral domain optical coherence tomography angiography enabled better visualization of capillary dropout and layer-specific assessment. Further research is required to determine whether vaccination in general, or directed specifically at N. meningitidis or yellow fever, is associated with small vessel vasculopathy and the underlying pathogenesis.


Canadian Journal of Ophthalmology-journal Canadien D Ophtalmologie | 2016

Clinical predictors of positive temporal artery biopsy

Andrew Toren; Ezekiel Weis; Vivek Patel; Bethany Monteith; Steven Gilberg; David R. Jordan

OBJECTIVE We investigated the ability of known clinical signs and symptoms, as well as common laboratory tests, to correctly predict a positive temporal artery biopsy. DESIGN A prospective cohort study. PARTICIPANTS Consecutive patients in a tertiary referral centre undergoing temporal artery biopsy. METHODS Clinical information was collected using a predesigned questionnaire. Pathology results and laboratory information were collected from digital patient records. MAIN OUTCOME MEASURE The predictive value of clinical signs, symptoms, and laboratory values of a positive temporal artery biopsy. RESULTS Over a 3-year period, 259 patients were enrolled and 251 patients were analyzed. Sixty-one patients had a positive biopsy. Clinical features most predictive of a positive biopsy were jaw claudication (positive likelihood ratio [LR+] 2.31) and abnormal temporal artery pulse (LR+ 2.62). Receiver operating characteristic curves generated for erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and platelets values showed an area under curve (AUC) value of 0.71, 0.75, and 0.76, respectively. The initiation of steroids decreased the diagnostic utility of the ESR, CRP, and platelets values (AUC = 0.58, 0.61, and 0.63, respectively). CONCLUSIONS A variety of clinical signs and symptoms were observed in patients referred for a temporal artery biopsy. Clinical signs and symptoms were less accurate in predicting a positive biopsy than laboratory tests. No combination of clinical signs and symptoms tested was able to predict giant cell arteritis with the certainty necessary to justify or withhold long-term steroid therapy.


Canadian Journal of Ophthalmology-journal Canadien D Ophtalmologie | 2017

Development of a predictive model for temporal artery biopsies

Ezekiel Weis; Andrew Toren; David R. Jordan; Vivek Patel; Steven Gilberg

OBJECTIVE Temporal artery biopsy is a critical, relatively safe, and reliable test in the diagnosis of temporal arteritis. Yet, a clarification of the pre-test probabilities may provide clarity on which patients with suspected giant cell arteritis would benefit from this invasive diagnostic procedure. DESIGN A prospective case series PARTICIPANTS: A consecutive case series of patients referred to the Ophthalmology service for temporal artery biopsy. METHODS All subjects underwent standardized serum testing, and signs and symptoms assessment. Predictive models were created and evaluated. RESULTS 119 patients were analyzed. This exploratory study found that a simple model including platelet count, erythrocyte sedimentation rate, and c-reactive protein was able to define a subset of patients with a pre-test probability of a positive biopsy of 0% or 100%. 40% (95% confidence interval 31%-49%) of patients fell into this category. CONCLUSIONS Utilizing a simple clinically applicable predictive model of the pretest probability of a temporal artery biopsy in patients with suspected giant cell arteritis, up to 31%-49% of temporal artery biopsies may be avoided. This study was a single site exploratory study with data-driven thresholds - therefore these results need to be validated with an independent sample prior to clinical use.


Current Treatment Options in Neurology | 2015

Treatment of Ocular Motor Palsies

Imran Jivraj; Vivek Patel

Opinion statementThe management of ocular motor palsies first requires careful determination of the etiology. Possibilities include ischemia, inflammation, infection, trauma, compression, or congenital. Prognosis for recovery varies greatly between etiologies; hence, determination of the underlying process is crucial in the short- and long-term management of these patients. Naturally, our ultimate goal is to improve visual function as much as possible. A guiding principle in the initial management of ocular motor palsies is to improve patient comfort and visual function by eliminating diplopia in primary position while clinically observing the patient for improvement or stability. Offering a definitive treatment which creates the largest possible zone of binocular single vision in primary and reading positions can be undertaken once stability has been demonstrated. In the initial phase after an acute ocular motor palsy has occurred, occlusion of an eye can be used to eliminate diplopia. Options include a patch or applying translucent or satin tape to one of the lenses which prevents diplopia but still lets light through. Alternatively, prismatic correction placed on or ground into spectacles may improve function and restore binocularity in patients with temporary or permanent ocular deviations. This is generally effective for patients with up to 20 to 25 prism diopters (PD) of horizontal misalignment and 10 to 15 PD of vertical. Once a stable misalignment has been demonstrated (several months), a variety of surgical options exist. Use of adjustable sutures, improved suture materials, and surgical techniques has expanded the role and scope of surgery for these patients. Planning the surgical approach is based on residual extraocular muscle function, careful measurements, and assessment of patient expectations.


Archive | 2017

Vertical and Horizontal Muscle Recessions With and Without Adjustable Suture

Vivek Patel

Patients should have been evaluated and deemed appropriate for such surgical intervention. Measurements of ocular misalignment need to be as precise as possible and stable for at least 6 months. If systemic thyroid status remains uncontrolled, surgery should be postponed until stability is achieved. If orbital decompression is considered, this should be performed before strabismus surgery, and orthoptic measurements repeated 2 months after decompression surgery. Clinical activity of the eye disease should also be minimal at the time of surgery.


Archive | 2017

Hummelsheim Transposition for Complete Paralytic Sixth Nerve Palsy

Vivek Patel

Patients should have been evaluated and deemed appropriate for such surgical intervention. Measurements of ocular misalignment need to be as precise as possible and stable for at least 6 months. A transposition of the vertical rectus muscles should be considered for patients with a complete or near complete sixth nerve palsy, given that a standard recess and resect procedure would not be sufficient to address the deficit in abduction.


American Journal of Ophthalmology Case Reports | 2017

Utility of optical coherence tomography angiography in detecting glaucomatous damage in a uveitic patient with disc congestion: A case report

Jiun Lap Do; Beau Sylvester; Anoush Shahidzadeh; Ruikang K. Wang; Zhongdi Chu; Vivek Patel; Grace M. Richter

Purpose To report a case of uveitic glaucoma with a congested optic disc where optical coherence tomography angiography (OCT-A) provided diagnostic utility in assessing glaucomatous damage but optical coherence tomography (OCT) alone had limited utility. Observations We report a case of a 33-year-old Caucasian female referred to the USC Roski Eye Institute for uncontrolled intraocular pressure (IOP) in the left eye. She was managed by an outside provider for 6 months, where her IOP ranged from 28 to 42 mm Hg in the left eye on maximally tolerated medical therapy. Her clinical exam was consistent with Herpes family trabeculitis, optic nerve congestion, and possible glaucomatous damage. Initial evaluation of the optic nerve by standard modalities (fundus exam and OCT) was limited by optic nerve congestion; however, OCT-A showed peripapillary hypoperfusion, as commonly observed in glaucomatous eyes. She underwent aqueous shunt implantation for elevated IOPs poorly controlled by medications. Conclusions and importance OCT-A can be a useful tool in the evaluation of glaucoma in instances where disc congestion masks both nerve excavation and retinal nerve fiber thinning normally seen on exam and on standard OCT of the optic nerve.

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Amir H. Kashani

University of Southern California

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Grace M. Richter

University of Southern California

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