Bio


Neil Kalwani, MD, MPP is a Clinical Instructor in the Division of Cardiovascular Medicine. He attended college at Yale University and completed graduate degrees in medicine and public policy at Harvard University. He trained in internal medicine at Brigham and Women’s Hospital before arriving at Stanford in 2018 for fellowship in cardiovascular medicine, during which he served as Chief Fellow. He then completed a postdoctoral fellowship through the Stanford-AHRQ Health Services Research Training Program in the Department of Health Policy. His clinical focus is in general and preventive cardiology and echocardiography. He practices at the VA Palo Alto Health Care System and at Stanford Health Care.

Dr. Kalwani's research focuses on the evaluation of policies and care delivery innovations designed to improve the value of care for patients with cardiovascular disease.

Clinical Focus


  • Cardiovascular Disease
  • Echocardiography
  • Preventive Medicine

Academic Appointments


Administrative Appointments


  • Chief Fellow, Division of Cardiovascular Medicine, Stanford School of Medicine (2020 - 2021)

Honors & Awards


  • Early Career Leadership Forum, California Chapter, American College of Cardiology (2022)
  • Early Career Investigator Abstract Award Semi-Finalist, AHA Quality of Care and Outcomes Research Conference Program Committee (2021)
  • General Winner, Stanford Resident/Fellow Quality Improvement & Patient Safety Symposium (2021)
  • Early Career Investigator Travel Award, AHA Quality of Care and Outcomes Research Conference Program Committee (2020)
  • Value-Based Health Care Delivery Intensive Seminar, Partners HealthCare Center of Expertise in Health Policy and Management and Harvard Business School (2017)
  • John H. Knowles Fellowship, Harvard Kennedy School (2013)

Boards, Advisory Committees, Professional Organizations


  • Member, American Society of Echocardiography (2022 - Present)
  • Member, American College of Cardiology (2018 - Present)
  • Member, American Heart Association (2018 - Present)

Professional Education


  • Postdoctoral Fellowship, Stanford University, Health Services Research (2022)
  • Board Certification: American Board of Internal Medicine, Cardiovascular Disease (2021)
  • Fellowship: Stanford School of Medicine (2021) CA
  • Board Certification, American Board of Internal Medicine, Internal Medicine (2018)
  • Residency: Brigham and Women's Hospital (2018) MA

All Publications


  • Impact of Patient-Reported Outcome Measurement in Heart Failure Clinic on Clinician Health Status Assessment and Patient Experience: A Sub-Study of the PRO-HF Trial. Circulation. Heart failure Sandhu, A. T., Zheng, J., Kalwani, N., Gupta, A., Calma, J., Skye, M., Lan, R., Yu, B., Spertus, J., Heidenreich, P. 2022

    Abstract

    Background: Clinicians typically estimate heart failure (HF) health status using the New York Heart Association (NYHA) class, which is often discordant with patient-reported health status. It is unknown if collecting patient-reported health status improves the accuracy of clinician assessments. Methods: The Patient-Reported Outcomes in Heart Failure Clinic (PRO-HF) trial is a randomized, non-blinded trial evaluating routine Kansas City Cardiomyopathy Questionnaire-12 (KCCQ-12) collection in HF clinic. Patients with a scheduled visit to Stanford HF clinic between August 30, 2021, and June 30, 2022 were enrolled and randomized to KCCQ-12 assessment or usual care. In this prespecified sub-study, we evaluated whether access to the KCCQ-12 improved the accuracy of clinicians' NYHA assessment or patients' perspectives on their clinician interaction. We surveyed clinicians regarding their patients' NYHA class, quality of life, and symptom frequency. Clinician responses were compared with patients' KCCQ-12 responses. We surveyed patients regarding their clinician interactions. Results: Of the 1,248 enrolled patients, 1,051 (84.2%) attended a visit during the sub-study. KCCQ-12 results were given to the clinicians treating the 528 patients in the KCCQ-12 arm; the 523 patients in the usual care arm completed the KCCQ-12 without the results being shared. The correlation between NYHA class and KCCQ-12 Overall Summary Score was stronger when clinicians had access to the KCCQ-12 (r=-0.73 vs. r=-0.61, p<0.001). More patients in the KCCQ-12 arm strongly agreed that their clinician understood their symptoms (95.2% vs. 89.7% of respondents; [OR 2.27; 95% CI: 1.32-3.87)]. However, patients in both arms reported similar quality of clinician communication and therapeutic alliance. Conclusions: Collecting the KCCQ-12 in HF clinic improved clinicians' accuracy of health status assessment; correspondingly, patients believed their clinicians better understood their symptoms. Registration: URL: ClinicalTrials.gov; Unique Identifier: NCT04164004.

    View details for DOI 10.1161/CIRCHEARTFAILURE.122.010280

    View details for PubMedID 36334312

  • The Patient-Reported Outcome Measurement in Heart Failure Clinic Trial: Rationale and Methods of The PRO-HF Trial. American heart journal Kalwani, N. M., Calma, J., Varghese, G. M., Gupta, A., Zheng, J., Brown-Johnson, C., Amano, A., Vilendrer, S., Winget, M., Asch, S. M., Heidenreich, P., Sandhu, A. 2022

    Abstract

    BACKGROUND: Among patients with heart failure (HF), patient-reported health status provides information beyond standard clinician assessment. Although HF management guidelines recommend collecting patient-reported health status as part of routine care, there is minimal data on the impact of this intervention.STUDY DESIGN: The Patient-Reported Outcomes in Heart Failure Clinic (PRO-HF) trial is a pragmatic, randomized, implementation-effectiveness trial testing the hypothesis that routine health status assessment via the Kansas City Cardiomyopathy Questionnaire-12 (KCCQ-12) leads to an improvement in patient-reported health status among patients treated in a tertiary health system HF clinic. PRO-HF has completed randomization of 1,248 participants to routine KCCQ-12 assessment or usual care. Patients randomized to the KCCQ-12 arm complete KCCQ-12 assessments before each HF clinic visit with the results shared with their treating clinician. Clinicians received education regarding the interpretation and potential utility of the KCCQ-12. The primary endpoint is the change in KCCQ-12 over 1 year. Secondary outcomes are HF therapy patterns and healthcare utilization, including clinic visits, testing, hospitalizations, and emergency department (ED) visits. As a sub-study, PRO-HF also evaluated the impact of routine KCCQ-12 assessment on patient experience and the accuracy of clinician-assessed health status. In addition, clinicians completed semi-structured interviews to capture their perceptions on the trial's implementation of routine KCCQ-12 assessment in clinical practice.CONCLUSIONS: PRO-HF is a pragmatic, randomized trial based in a real-world HF clinic to determine the feasibility of routinely assessing patient-reported health status and the impact of this intervention on health status, care delivery, patient experience, and the accuracy of clinician health status assessment.

    View details for DOI 10.1016/j.ahj.2022.10.081

    View details for PubMedID 36309127

  • Drivers of variation in telemedicine use during the COVID-19 pandemic: The experience of a large academic cardiovascular practice. Journal of telemedicine and telecare Koos, H., Parameswaran, V., Claire, S., Chen, C., Kalwani, N., Osmanlliu, E., Qureshi, L., Dash, R., Scheinker, D., Rodriguez, F. 2022: 1357633X221130288

    Abstract

    BACKGROUND: COVID-19 spurred rapid adoption and expansion of telemedicine. We investigated the factors driving visit modality (telemedicine vs. in-person) for outpatient visits at a large cardiovascular center.METHODS: We used electronic health record data from March 2020 to February 2021 from four cardiology subspecialties (general cardiology, electrophysiology, heart failure, and interventional cardiology) at a large academic health system in Northern California. There were 21,912 new and return visits with 69% delivered by telemedicine. We used hierarchical logistic regression and cross-validation methods to estimate the variation in visit modality explained by patient, clinician, and visit factors as measured by the mean area under the curve.RESULTS: Across all subspecialties, the clinician seen was the strongest predictor of telemedicine usage, while primary visit diagnosis was the next most predictive. In general cardiology, the model based on clinician seen had a mean area under the curve of 0.83, the model based on the primary diagnosis had a mean area under the curve of 0.69, and the model based on all patient characteristics combined had a mean area under the curve of 0.56. There was significant variation in telemedicine use across clinicians within each subspecialty, even for visits with the same primary visit diagnosis.CONCLUSION: Individual clinician practice patterns had the largest influence on visit modality across subspecialties in a large cardiovascular medicine practice, while primary diagnosis was less predictive, and patient characteristics even less so. Cardiovascular clinics should reduce variability in visit modality selection through standardized processes that integrate clinical factors and patient preference.

    View details for DOI 10.1177/1357633X221130288

    View details for PubMedID 36214200

  • DRIVERS OF VARIATION IN TELEMEDICINE USE AT AN ACADEMIC CARDIOVASCULAR CENTER DURING THE COVID-19 PANDEMIC Koos, H., Parameswaran, V., Claire, S., Chen, C., Kalwani, N., Osmanlliu, E., Dash, R., Scheinker, D., Rodriguez, F. ELSEVIER SCIENCE INC. 2022: 2046
  • Changes in telemedicine use and ambulatory visit volumes at a multispecialty cardiovascular center during the COVID-19 pandemic. Journal of telemedicine and telecare Kalwani, N. M., Osmanlliu, E., Parameswaran, V., Qureshi, L., Dash, R., Heidenreich, P. A., Scheinker, D., Rodriguez, F. 1800: 1357633X211073428

    Abstract

    Early in the COVID-19 pandemic, cardiology clinics rapidly implemented telemedicine to maintain access to care. Little is known about subsequent trends in telemedicine use and visit volumes across cardiology subspecialties. We conducted a retrospective cohort study including all patients with ambulatory visits at a multispecialty cardiovascular center in Northern California from March 2019 to February 2020 (pre-COVID) and March 2020 to February 2021 (COVID). Telemedicine use increased from 3.5% of visits (1200/33,976) during the pre-COVID period to 63.0% (21,251/33,706) during the COVID period. Visit volumes were below pre-COVID levels from March to May 2020 but exceeded pre-COVID levels after June 2020, including when local COVID-19 cases peaked. Telemedicine use was above 75% of visits in all cardiology subspecialties in April 2020 and stabilized at rates ranging from over 95% in electrophysiology to under 25% in heart transplant and vascular medicine. From June 2020 to February 2021, subspecialties delivering a greater percentage of visits through telemedicine experienced larger increases in new patient visits (r=0.81, p=0.029). Telemedicine can be used to deliver a significant proportion of outpatient cardiovascular care though utilization varies across subspecialties. Higher rates of telemedicine adoption may increase access to care in cardiology clinics.

    View details for DOI 10.1177/1357633X211073428

    View details for PubMedID 35108126

  • Initial Outcomes of CardioClick, a Telehealth Program for Preventive Cardiac Care: Observational Study. JMIR cardio Kalwani, N. M., Johnson, A. N., Parameswaran, V., Dash, R., Rodriguez, F. 2021; 5 (2): e28246

    Abstract

    BACKGROUND: Telehealth use has increased in specialty clinics, but there is limited evidence on the outcomes of telehealth in primary cardiovascular disease (CVD) prevention.OBJECTIVE: The objective of this study was to evaluate the initial outcomes of CardioClick, a telehealth primary CVD prevention program.METHODS: In 2017, the Stanford South Asian Translational Heart Initiative (a preventive cardiology clinic focused on high-risk South Asian patients) introduced CardioClick, which is a clinical pathway replacing in-person follow-up visits with video visits. We assessed patient engagement and changes in CVD risk factors in CardioClick patients and in a historical in-person cohort from the same clinic.RESULTS: In this study, 118 CardioClick patients and 441 patients who received in-person care were included. CardioClick patients were more likely to complete the clinic's CVD prevention program (76/118, 64.4% vs 173/441, 39.2%, respectively; P<.001) and they did so in lesser time (mean, 250 days vs 307 days, respectively; P<.001) than the patients in the historical in-person cohort. Patients who completed the CardioClick program achieved reductions in CVD risk factors, including blood pressure, lipid concentrations, and BMI, which matched or exceeded those observed in the historical in-person cohort.CONCLUSIONS: Telehealth can be used to deliver care effectively in a preventive cardiology clinic setting and may result in increased patient engagement. Further studies on telehealth outcomes are needed to determine the optimal role of virtual care models across diverse preventive medicine clinics.

    View details for DOI 10.2196/28246

    View details for PubMedID 34499037

  • High-Deductible Health Plans and Emergency Care for Chest Pain: To Go or Not to Go? Circulation Kalwani, N. M., Sandhu, A. T. 2021

    View details for DOI 10.1161/CIRCULATIONAHA.121.055368

    View details for PubMedID 34176296

  • STATIN ADHERENCE AFTER HEART TRANSPLANTATION: AN OUTCOMES ANALYSIS Li, K., Kalwani, N., Sandhu, A., Khush, K., Fearon, W. ELSEVIER SCIENCE INC. 2021: 569
  • Application of the Quadruple Aim to evaluate the operational impact of a telemedicine program. Healthcare (Amsterdam, Netherlands) Kalwani, N. M., Wang, K. M., Johnson, A. N., Deb, J. D., Gold, T., Maddukuri, A. K., Savage, E. G., Parameswaran, V., Dash, R., Scheinker, D., Rodriguez, F. 2021; 9 (4): 100593

    Abstract

    In response to the COVID-19 pandemic, telemedicine utilization has increased dramatically, yet most institutions lack a standardized approach to determine how much to invest in these programs.We used the Quadruple Aim to evaluate the operational impact of CardioClick, a program replacing in-person follow-up visits with video visits in a preventive cardiology clinic. We examined data for 134 patients enrolled in CardioClick with 181 video follow-up visits and 276 patients enrolled in the clinic's traditional prevention program with 694 in-person follow-up visits.Patients in CardioClick and the cohort receiving in-person care were similar in terms of age (43 vs 45 years), gender balance (74% vs 79% male), and baseline clinical characteristics. Video follow-up visits were shorter than in-person visits in terms of clinician time (median 22 vs 30 min) and total clinic time (median 22 vs 68 min). Video visits were more likely to end on time than in-person visits (71 vs 11%, p < .001). Physicians more often completed video visit documentation on the day of the visit (56 vs 42%, p = .002).Implementation of video follow-up visits in a preventive cardiology clinic was associated with operational improvements in the areas of efficiency, patient experience, and clinician experience. These benefits in three domains of the Quadruple Aim justify expanded use of telemedicine at our institution.The Quadruple Aim provides a framework to evaluate telemedicine programs recently implemented in many health systems.Level III (retrospective comparative study).

    View details for DOI 10.1016/j.hjdsi.2021.100593

    View details for PubMedID 34749227

  • Management of Lymphatic Vascular Malformations: A Systematic Review of the Literature. Journal of vascular surgery. Venous and lymphatic disorders Kalwani, N. M., Rockson, S. G. 2021

    Abstract

    Lymphatic malformations (LM) are common congenital vascular lesions, most often diagnosed at birth. They deform local anatomy and can be life-threatening if they compress the aerodigestive tract or other vital structures. Significant progress has been made in the treatment of LM in the past twenty years. We conducted a systematic review of the literature on the management of LM.On September 21, 2020, we searched PubMed/MEDLINE for studies published from 2000 to 2020 reporting outcomes of invasive and pharmacologic treatment of LM.A total of 251 studies met eligibility criteria. Surgery continues to be a mainstay in the management of LM, especially in the treatment of microcystic and mixed lesions. Sclerotherapy has emerged as a first-line treatment for macrocystic LM and as an adjunctive therapy used in combination with surgery for other lesions. Sirolimus, a strong inhibitor of mTOR, has shown tremendous promise in the treatment of LM, both as an oral and a topical agent. Recent investigations have shown the potential of targeted small molecule modulators of cellular pathways in the treatment of LM.Multiple invasive and pharmacologic therapies have been shown to be effective in the treatment of LM. Future research should focus on rigorous, prospective comparisons of these treatment modalities.

    View details for DOI 10.1016/j.jvsv.2021.01.013

    View details for PubMedID 33540133

  • Elective Percutaneous Coronary Intervention in Ambulatory Surgery Centers. JACC. Cardiovascular interventions Li, K., Kalwani, N. M., Heidenreich, P. A., Fearon, W. F. 2020

    Abstract

    OBJECTIVES: The aim of this study was to explore characteristics and outcomes of patients undergoing elective percutaneous coronary intervention (PCI) in ambulatory surgery centers (ASCs).BACKGROUND: Little is known about patients who underwent ASC PCI before Medicare reimbursement was instituted in2020.METHODS: Using commercial insurance claims from MarketScan, adults who underwent hospital outpatient department (HOPD) or ASC PCI for stable ischemic heart disease from 2007 to 2016 were studied. Propensity score analysis was used to measure the association between treatment setting and the primary composite outcome of 30-day myocardial infarction, bleeding complications, and hospital admission.RESULTS: The unmatched sample consisted of 95,492 HOPD and 849 ASC PCIs. Patients who underwent ASC PCI were more likely to be younger than 65 years, to live in the southern United States, and to have managed or consumer-driven health insurance. ASC PCI was also associated with decreased fractional flow reserve utilization (odds ratio [OR]: 0.31; 95% confidence interval [CI]: 0.20 to 0.48; p<0.001). In unmatched, multivariate analysis, ASC PCI was associated with increased odds of the primary outcome (OR: 1.25; 95%CI: 1.01 to 1.56; p=0.039) and bleeding complications (OR: 1.80; 95%CI: 1.11 to 2.90; p=0.016). In propensity-matched analysis, ASC PCI was not associated with the primary outcome (OR: 1.23; 95%CI: 0.94 to 1.60; p=0.124) but was significantly associated with increased bleeding complications (OR: 2.49; 95%CI: 1.25 to 4.95; p=0.009).CONCLUSIONS: Commercially insured patients undergoing ASC PCI were less likely to undergo fractional flow reserve testing and had higher odds of bleeding complications than HOPD-treated patients. Further study is warranted as Medicare ASC PCI volume increases.

    View details for DOI 10.1016/j.jcin.2020.10.015

    View details for PubMedID 33183992

  • Electrical Storm in COVID-19. JACC. Case reports O'Brien, C. n., Ning, N. n., McAvoy, J. n., Mitchell, J. E., Kalwani, N. n., Wang, P. n., Nguyen, D. n., Reejhsinghani, R. n., Rogers, A. n., Lorenzo, J. n. 2020; 2 (9): 1256–60

    Abstract

    COVID-19 is a global pandemic caused by SARS-CoV-2. Infection is associated with significant morbidity and mortality. Individuals with pre-existing cardiovascular disease or evidence of myocardial injury are at risk for severe disease and death. Little is understood about the mechanisms of myocardial injury or life-threatening cardiovascular sequelae. (Level of Difficulty: Intermediate.).

    View details for DOI 10.1016/j.jaccas.2020.05.032

    View details for PubMedID 32835266

    View details for PubMedCentralID PMC7259914

  • Longer-term impact of cardiology e-consults. American heart journal Wasfy, J. H., Rao, S. K., Kalwani, N., Chittle, M. D., Richardson, C. A., Gallen, K. M., Isselbacher, E. M., Kimball, A. B., Ferris, T. G. 2016; 173: 86-93

    Abstract

    Cardiac e-consults may be an effective way to deliver value-oriented outpatient cardiology care in an accountable care organization. Initial results of cardiac e-consults have demonstrated high satisfaction among both patients and referring providers, no known adverse events, and low rates of diagnostic testing. Nevertheless, differences between e-consults and traditional consults, effects of e-consults on traditional consult volume, and whether patients seek traditional consults after e-consults are unknown.We established a cardiac e-consult program on January 13, 2014. We then conducted detailed medical record reviews of all patients with e-consults to detect any adverse clinical events and detect subsequent traditional visits to cardiologists. We also performed 2 comparisons. First, we compared age, gender, and referral reason for e-consults vs traditional consults. Second, we compared changes in volume of referrals to cardiology vs other medical specialties that did not have e-consults. From January 13 to December 31, 2014, 1,642 traditional referrals and 165 e-consults were requested. The proportion of e-consults of all evaluations requested over that period was 9.1%. Gender balance was similar among traditional consults and e-consults (44.8% male for e-consults vs 45.0% for traditional consults, P = .981). E-consult patients were younger than traditional consult patients (55.3 vs 60.4 years, P < .001). After the introduction of cardiac e-consults, the increase in traditional cardiac visit requests was less than the increase in traditional visit requests for control specialties (4.5% vs 10.1%, P < .001). For e-consults with at least 6 months of follow-up, 75.6% patients did not have any type of traditional cardiology visit during the follow-up period.E-consults are an effective and safe mechanism to enhance value in outpatient cardiology care, with low rates of bounceback to traditional consults. E-consults can account for nearly one-tenth of total outpatient consultation volume at 1 year within an accountable care organization and are associated with a reduction in traditional referrals to cardiologists.

    View details for DOI 10.1016/j.ahj.2015.11.019

    View details for PubMedID 26920600

  • Plasmacytoma of the Clivus Presenting as Bilateral Sixth Nerve Palsy. Journal of neurological surgery reports Kalwani, N., Remenschneider, A. K., Faquin, W., Ferry, J., Holbrook, E. H. 2015; 76 (1): e156-9

    Abstract

    Background and Importance Plasmacytomas are monoclonal proliferations of plasma cells that may arise within soft tissue or bone. The skull base is a rare site for plasmacytomas to occur, and few cases have been reported in the literature. When present in the skull base, plasmacytomas may result in cranial neuropathies and often progress to multiple myeloma more rapidly than other intracranial or skeletal plasmacytomas. Clinical Presentation A 69-year-old man presented with a primary complaint of diplopia and an examination consistent with bilateral abducens nerve palsy. No other deficits were noted. Magnetic resonance imaging of the skull base demonstrated a large T1 isointense moderately enhancing lesion centered within the clivus. Endoscopic biopsy of the mass revealed sheets and aggregates of mature monoclonal plasma cells. The patient's initial systemic work-up revealed that this was a solitary lesion, and he was treated with radiation therapy to the skull base with a durable local effect at 18-month follow-up. Unfortunately he progressed to multiple myeloma with peripheral osteolytic lesions but has been stabilized on chemotherapeutics. Conclusion The clivus is an unusual site for intracranial plasmacytomas, and enhancing lesions must be differentiated from chordoma. Characteristic findings on histopathology include an immunoglobulin light-chain restricted clonal proliferation of plasma cells. Treatment is most commonly radiotherapy with surgery reserved for biopsy and palliation. Clinicians should be aware of the increased risk of progression to multiple myeloma in skull base plasmacytomas.

    View details for DOI 10.1055/s-0035-1554930

    View details for PubMedID 26251795

    View details for PubMedCentralID PMC4520983

  • FGF23 deficiency leads to mixed hearing loss and middle ear malformation in mice. PloS one Lysaght, A. C., Yuan, Q. n., Fan, Y. n., Kalwani, N. n., Caruso, P. n., Cunnane, M. n., Lanske, B. n., Stanković, K. M. 2014; 9 (9): e107681

    Abstract

    Fibroblast growth factor 23 (FGF23) is a circulating hormone important in phosphate homeostasis. Abnormal serum levels of FGF23 result in systemic pathologies in humans and mice, including renal phosphate wasting diseases and hyperphosphatemia. We sought to uncover the role FGF23 plays in the auditory system due to shared molecular mechanisms and genetic pathways between ear and kidney development, the critical roles multiple FGFs play in auditory development and the known hearing phenotype in mice deficient in klotho (KL), a critical co-factor for FGF23 signaling. Using functional assessments of hearing, we demonstrate that Fgf[Formula: see text] mice are profoundly deaf. Fgf[Formula: see text] mice have moderate hearing loss above 20 kHz, consistent with mixed conductive and sensorineural pathology of both middle and inner ear origin. Histology and high-voltage X-ray computed tomography of Fgf[Formula: see text] mice demonstrate dysplastic bulla and ossicles; Fgf[Formula: see text] mice have near-normal morphology. The cochleae of mutant mice appear nearly normal on gross and microscopic inspection. In wild type mice, FGF23 is ubiquitously expressed throughout the cochlea. Measurements from Fgf[Formula: see text] mice do not match the auditory phenotype of Kl-/- mice, suggesting that loss of FGF23 activity impacts the auditory system via mechanisms at least partially independent of KL. Given the extensive middle ear malformations and the overlap of initiation of FGF23 activity and Eustachian tube development, this work suggests a possible role for FGF23 in otitis media.

    View details for DOI 10.1371/journal.pone.0107681

    View details for PubMedID 25243481

    View details for PubMedCentralID PMC4171482

  • Quantitative polarized light microscopy of unstained mammalian cochlear sections. Journal of biomedical optics Kalwani, N. M., Ong, C. A., Lysaght, A. C., Haward, S. J., McKinley, G. H., Stankovic, K. M. 2013; 18 (2): 26021

    Abstract

    Hearing loss is the most common sensory deficit in the world, and most frequently it originates in the inner ear. Yet, the inner ear has been difficult to access for diagnosis because of its small size, delicate nature, complex three-dimensional anatomy, and encasement in the densest bone in the body. Evolving optical methods are promising to afford cellular diagnosis of pathologic changes in the inner ear. To appropriately interpret results from these emerging technologies, it is important to characterize optical properties of cochlear tissues. Here, we focus on that characterization using quantitative polarized light microscopy (qPLM) applied to unstained cochlear sections of the mouse, a common animal model of human hearing loss. We find that the most birefringent cochlear materials are collagen fibrils and myelin. Retardance of the otic capsule, the spiral ligament, and the basilar membrane are substantially higher than that of other cochlear structures. Retardance of the spiral ligament and the basilar membrane decrease from the cochlear base to the apex, compared with the more uniform retardance of other structures. The intricate structural details revealed by qPLM of unstained cochlear sections ex vivo strongly motivate future application of polarization-sensitive optical coherence tomography to human cochlea in vivo.

    View details for DOI 10.1117/1.JBO.18.2.026021

    View details for PubMedID 23407909

    View details for PubMedCentralID PMC3571355