About

Professor Rouzbeh Amini is an Associate Professor in the Department of Bioengineering at Northeastern University College of Engineering. His research focuses on brain imaging analysis, particularly related to brain diseases such as Chiari Malformation Type 1. He is involved in interdisciplinary research that aims to understand brain tissue motion and its relationship to symptoms and surgical outcomes, contributing valuable insights into the biomarker discovery process for this condition. He is recognized for his contributions to the field through collaborative research efforts, including a recent publication in the Magnetic Resonance Imaging journal, where his team investigated the correlation between brain tissue motion and surgical results in Chiari Malformation patients. His work emphasizes the importance of rigorous data analysis and integrity, underscoring that results which do not support initial hypotheses are equally valuable. Professor Amini's research is characterized by a commitment to advancing human health through innovative imaging techniques and data analysis, fostering a deeper understanding of brain mechanics and pathology.

Research topics

• Medicine
• Radiology
• Nuclear medicine
• Internal medicine
• Anatomy
• Physics
• Optics
• Mathematics
• Materials science
• Acoustics
• Surgery
• Biomedical engineering
• Biology
• Pathology
• Neuroscience
• Nuclear magnetic resonance

Selected publications

• An Integrated Multiphoton Imaging Workflow for Quantitative Analysis of Aortic Tissue Microstructure

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-01-27

  article

  Abstract Quantitative, reproducible characterization of aortic microstructure is essential for advancing vascular biomechanics and mechanobiology. To address this need, we present a comprehensive image-analysis workflow that extracts quantitative descriptors of tissue microstructure from multiphoton microscopy stacks of the murine thoracic aorta. Channel-specific signals are acquired for fibrillar collagen (second harmonic generation), elastin (two-photon autofluorescence), and cell nuclei (two-photon excited fluorescence). Following reorientation into the XZ plane, individual elastic lamellae are traced to quantify lamellar thickness and interlamellar spacing using circle-based geometry (Taubin fitting). After correction for vessel wall curvature via a cylindrical transformation, segmented nuclei are assigned to medial or adventitial compartments based on visual estimates of adventitial volume fraction, and nuclear morphology is characterized via ellipsoidal fitting in terms of nuclear aspect ratio and major-axis orientation. Collagen organization is resolved in XY sections by extracting fiber centerlines to quantify straightness and amplitude; traces from serial sections are then combined to reconstruct the three-dimensional collagen network and estimate porosity and linear fiber density, while fiber orientation distributions are derived from principal component analysis–based angles and fit using a von Mises mixture model. Finally, collagen and elastin volume fractions are computed via a two-stage fixed-threshold approach calibrated on a balanced training subset. Overall, this modular and robust workflow provides an integrated framework for studying aortic wall remodeling across physiological and pathological processes. Non-Technical Summary As the main blood vessel in our body, the aorta needs to be both strong and flexible. This balance comes from three main parts: elastic layers that allow the aorta to stretch, strong fibers that prevent tearing, and cells that sense and respond to changes in blood pressure and other signals. When any of these components are altered, the aorta may stiffen or weaken, which can interfere with normal blood flow. In this study, we developed a clear and consistent way to measure the structure of the aortic wall using microscope images. The approach examines how thick the elastic layers are and how far apart they lie, the size and orientation of cell centers, and how straight or wavy structural fibers appear. It also estimates how much of each component is present in the aortic wall. Because the same steps are applied each time, results can be fairly compared across different conditions. Overall, this tool transforms detailed images into simple measurements, helping scientists understand how the aorta changes in health and disease.

  PublisherDOI

• An examination of atlanto-occipital curvature in adult Chiari malformation type 1 and control groups

  Journal of Craniovertebral Junction and Spine · 2026-05-01

  articleOpen access

  ABSTRACT Objective: To compare computed tomography (CT) scan-based morphometric measures associated with atlanto-occipital joint (AOJ) instability between Chiari malformation type I (CMI) patients and controls and to examine associations between these measures, clinical symptoms, and established craniocervical/posterior fossa morphometrics in CMI. Materials and Methods: Four AOJ-related morphometric measures were evaluated on CT: condyle–C1 interval (CCI), C1 socket depth-to-length ratio (DL ratio), condyle depth-to-depth ratio (CD ratio), and atlas tilt angle. Measurements were compared between CMI ( n = 45) and controls ( n = 55). Within CMI, associations were tested between AOJ measures and symptom variables, as well as 13 established craniocervical/posterior fossa morphometrics. Results: Mean CCI was slightly larger in CMI than in controls (1.00 vs. 0.91 mm, P < 0.05). DL ratio, CD ratio, and atlas tilt angle did not differ significantly between groups. Within CMI, CCI showed a modest association with hypermobility ( r = 0.34, P < 0.05). Moderate correlations were observed between AOJ measures and selected morphometrics, suggesting relationships between AOJ geometry and posterior fossa/craniocervical anatomy. Conclusion: Among the AOJ measures examined, only CCI demonstrated a small but statistically significant group difference and a modest association with hypermobility in CMI. The shape of the AOJ curvature was not different between CMI and control. However, further investigation of AOJ-related morphometrics as potential contributors to symptom heterogeneity among CMI patients is necessary.

  PublisherDOI

• Capturing sclera anisotropy using direct collagen fiber models: linking microstructure to macroscopic mechanical properties

  Biomechanics and Modeling in Mechanobiology · 2026-01-09

  article
  PublisherDOI

• Chordae Rupture Alters Tricuspid Valve Leaflet Biomechanics

  Cardiovascular Engineering and Technology · 2026-01-05

  articleOpen accessSenior authorCorresponding

  Abstract Purpose Tricuspid valve chordae tendineae rupture is a valvular lesion that is often overlooked, though is postulated to be more prevalent than currently known. We examined the hemodynamics and biomechanical response of the tricuspid valve leaflets following chordae rupture to understand how acute changes in the post-rupture mechanical environment may contribute to long-term remodeling responses. Methods Porcine valve leaflet deformation was studied in an intact heart in an ex vivo setup using sonomicrometry techniques before and after chordae rupture, which was induced by severing a chordae bundle connected to the septal leaflet. Results Following chordae rupture, pulmonary artery pressure dropped approximately 5 mmHg ( $$p=0.048$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0.048</mml:mn> </mml:mrow> </mml:math> ), indicating that valvular regurgitation occurred immediately after rupture. Mean maximum principal stretch of the septal leaflet increased 12% after rupture ( $$p=0.006$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0.006</mml:mn> </mml:mrow> </mml:math> ). Conclusion The immediate changes in post-rupture septal leaflet stretches show that chordae tendineae rupture acutely alters the biomechanical environment of the tricuspid valve, which may result in chronic tissue remodeling responses. Non-technical Summary The tricuspid valve is one of the four valves in the heart. Rupture of supporting structures of the tricuspid valve leaflet, known as chordae tendineae, may be more common than previously thought. In this study, we used excised pig hearts to examine how chordae rupture affects valvular function. With our experimental beating heart system, we pumped fluid through the hearts under realistic conditions and measured changes in pressure and leaflet motion before and after chordae rupture. After rupture, we observed a change in pressures and leaflet motion, causing the valve to leak and become less efficient. These changes may influence how the valve functions over time.

  PublisherOA PDFDOI

• Population Variations in Helmet Fit Affect Calculated Head Injury Risk in Blunt Impact

  Journal of Biomechanical Engineering · 2025-12-13

  articleOpen access

  A helmet will not fit the same way on different individuals with different head sizes and shapes. However, the degree to which subject-specific fit differences may affect the risk of injury remains understudied. In this study, we used experimentally measured head/helmet contact force to generate different levels of initial padding compression when applied to a finite element head model. The deformed padding configuration was used as the initial condition for subsequent blunt impact analyses. As the level of initial padding compression increased, the resulting maximum force, total impulse, and the resulting head injury metrics increased by up to 20%. The results of this study highlight the importance of accurate modeling of initial pad deformation before blunt impact and provide a workflow for establishing such a configuration in other helmet applications. Intuitively, two different people wearing an identical helmet will experience a different fit, since the size and shape of their heads will differ. However, it is unclear how that variation in fit will affect the risk of injury for most helmet types. In this study, we generated different helmet fit conditions in a simulated model of a head and helmet, based on previous experimental measurements of the force between the helmet padding and the head. Four conditions were generated: zero, low, medium, and high initial fitting forces. Using the different fit configurations, we simulated two types of impacts on the front, back, side, and top of the helmet, and calculated the risk of injury to the brain and skull. Our results suggest that differences in padding compression arising from differences in head shape can significantly change the risk of injury. Higher initial padding compression resulted in greater force applied to the head and higher values of brain and skull injury metrics. These effects were more apparent for lower energy impacts, suggesting that the differences might be important to consider for helmets where the user sees repeated, low-intensity impacts such as in American football. Our analysis was limited to one type of helmet, and we were unable to vary the geometry of the head, meaning that the data should be interpreted cautiously. However, our results provide compelling evidence that the level of initial compression in the padding due to the user's head is an important factor to incorporate when designing new helmets.

  PublisherDOI

• Toward a Consistent Framework for Describing the Free Vibration Modes of the Brain

  Journal of Biomechanical Engineering · 2025-01-22 · 5 citations

  articleOpen access

  Frequency-domain analysis of brain tissue motion has received increased focus in recent years as an approach to describing the response of the brain to impact or vibration sources in the built environment. While researchers in many experimental and numerical studies have sought to identify natural resonant frequencies of the brain, sparse description of the associated vibration modes limits comparison of results between studies. We performed a modal analysis to extract the natural frequencies and associated mode shapes of a finite element (FE) model of the head. The vibration modes were characterized using two-dimensional (2D) plate deformation notation in the basic medical planes. Many of the vibration modes characterized are similar to those found in previous numerical and experimental studies. We propose this characterization method as an approach to increase compatibility of results between studies of brain vibration behavior.

  PublisherOA PDFDOI

• Cardiac-induced brain tissue motion in Chiari Malformation type 1 subjects and its relationship to symptomatology, morphometrics, and surgical outcomes

  Magnetic Resonance Imaging · 2025-09-22

  articleOpen access

  PURPOSE: To determine whether cardiac-induced brain-tissue displacement in Chiari Malformation type 1 (CMI) relates to patient symptoms, morphometrics, and surgical outcomes. METHODS: We performed cardiac-gated phase-contrast MRI in 45 adults with CMI, converting velocity measurements to voxel-wise displacement in the cerebellum, pons, medulla, and cervical cord. We examined if displacement was correlated with each symptoms of subjects, and two anatomic measurements: tonsillar position (TP) and the ratio of neural-tissue area at foramen magnum to the area of foramen magnum. In seven patients who underwent posterior fossa decompression (PFD), we compared pre- versus post-operative displacement in seven paired scans and related changes to the Chicago Chiari Outcome Scale (CCOS). RESULTS: No significant correlations were found between displacement and symptom reports. TP correlated moderately with displacement (r = 0.47-0.61, p < 0.002), and ratio of neural-tissue area showed modest links to cerebellar motion (r = 0.34-0.36, p < 0.02). After PFD, mean and peak cerebellar displacement decreased by 45 % and 60 %, respectively (p < 0.05), but neither pre-operative motion nor its reduction predicted CCOS scores. CONCLUSION: While displacement increases with anatomical crowding and normalizes after surgery, it does not predict clinical symptoms or surgical outcomes. Future work should combine multiple biomechanical markers and detailed symptom scales in an effort to develop a multidimensional biomarker for guiding treatment and assessing recovery in CMI.

  PublisherDOI

• Extracellular matrix repair and organization of chronic infected diabetic wounds treated with methacrylated chitosan-based hydrogels

  Acta Biomaterialia · 2025-05-01 · 10 citations

  articleOpen access

  Diabetic foot ulcers (DFUs) are a multifactorial medical problem that require multifaceted approaches for effective healing. Most research on DFU healing has concentrated on promoting wound closure, with less emphasis on the quality of repaired tissue. This is problematic, however, since quality of the repaired tissues can have potential to improve wound healing outcomes and limit re-ulceration. If more functionally active dermis replaces the lost tissue, this can effectively maximize strength, organization, and overall structure of the plantar surface. Additionally, DFUs commonly show multi-strain infection, which further exacerbates the non-healing status of these wounds. Treatment of chronic wounds can be benefitted by application of oxygen and localized infection treatment, both can be achieved via our methacrylated chitosan-based (MACF) hydrogel. A non-healing diabetic infected wound model was used to explore extracellular matrix (ECM) organization, tensile strength, and metabolomic profiles at a 21-day endpoint as a marker for maturation and improved functionality of repaired tissues over normal scar formation. Effective remediation of infection was achieved with 14 days of polyhexamethylene biguanide (PHMB) application with improved wound repair compared to continuous treatment. Prolonged (21 day) application of PHMB showed resulting necrosis, although standard application times for patients with infected wounds can reach up to 28 continuous days. Biaxial mechanical analysis showed improved isotropic strength of infected tissues treated with MACF with PHMB stopped on D14, supported by collagen fiber orientation in second harmonics generation (SHG) imaging. Oxygenating MACF treatments also improved collagen deposition through the enhancement of the hydroxyproline fibrillary collagen synthesis pathway. These structural and mechanical results demonstrate a promising potential treatment for infected diabetic foot ulcers which shows improved dermal functionality. STATEMENT OF SIGNIFICANCE: Diabetic foot ulcers are a multifaceted problem in the medical field exacerbated by infection, with potential for gangrene, lower limb amputation, sepsis, or death. Current treatment regimens include oxygen therapy, physical debridement, and strong antibacterials. However, there is a lack of multi-faceted approaches, which we have designed in our oxygenating chitosan-based hydrogels capable of delivering antibiotics. Treatments currently focus on closure of wounds; however, functionality of regenerated tissues are limited due to fibrotic scar formation. Therefore, we have chosen to focus not only on closure, but also quality of regenerated tissues through mechanical testing and analysis of extracellular matrix composition and organization, with a goal of improving functionality of regenerated tissues.

  PublisherDOI

• Measurement and Assessment of Head-to-Helmet Contact Forces

  Annals of Biomedical Engineering · 2025-01-25 · 7 citations

  articleOpen accessSenior author

  PURPOSE: To evaluate the population variation in head-to-helmet contact forces in helmet users. METHODS: Four different size Kevlar composite helmets were instrumented with contact pressure sensors and chinstrap tension meters. A total number of 89 volunteers (25 female and 64 male volunteers) participated in the study. The length, width, and circumference of their heads were measured and each volunteer was assigned a helmet size. Volunteers were asked to wear the helmet in three different configurations and the chinstrap tension and contact force between the head and each of the seven interior pads were recorded. RESULTS: The majority of forces measured on any individual pad were between 0 and 5 N. However, some users exhibited pressure points with forces as high as 30 N. The contact force distribution is non-uniform across the interior of the helmet, with the largest force concentrated at the front. Head shape is a major driver of the observed contact force. There was a statistically significant difference between female and male volunteers, and between groups with different experience levels. CONCLUSIONS: The fit of helmet systems is highly subject specific. The current metrics used to assign helmet sizes may not accurately predict correct helmet fit.

  PublisherOA PDFDOI

• Impact of pupillary dilation on the efficacy of laser peripheral iridotomy

  Artificial Intelligence in Vision and Ophthalmology · 2025-09-15 · 2 citations

  articleOpen accessSenior author

  Purpose: To assess outcomes of laser peripheral iridotomy (LPI) procedures following dilation by evaluating the pressure difference across the iris posterior-anterior chamber resulting from varying hole sizes and locations. Methods: Using an anterior segment optical coherence tomography (AS-OCT) image, we created a 3-D finite element model of the iris. We then manually identified a dilator region where the dilator stress was applied to simulate pupillary dilation. To mimic LPI, we made a hole of 200 microns in diameter near the pupillary margin, at the mid-periphery, and at the periphery of the iris. Using computational fluid dynamics methods, we computed the pressure difference developed by the hole before and after pupil dilation at each location. This process was then repeated with a hole of 400 microns in diameter. Results: The pressure difference developed across a 200-micron hole when the hole was placed near the pupil, at the iris mid-periphery, and near the iris periphery was 0.85 Pa, 0.80 Pa, and 0.92 Pa, respectively. Following pupil dilation, the pressure difference increased in all cases. For the compressible iris model, the pressure increased by 4.70%, 63.75%, and 52.17% near the pupil, at the iris mid-periphery, and near the iris periphery, respectively. For the nearly incompressible model, the pressure increased by 7.06%, 51.25%, and 55.43% near the pupil, at the iris mid-periphery, and near the iris periphery, respectively. Across a 400-micron diameter hole, the pressure difference developed was extremely small (&lt; 0.1 Pa) across all cases, both before and following dilation. Conclusion: While LPI offers a solution for narrow or closed anterior chamber angles, in some patient populations the angles remain occludable following LPI. One possible reason could be attributed to the additional pressure difference across the anterior and posterior chamber due to the change in LPI hole size following dilation-inducediris deformation. Our study shows that the LPI hole size/location affects the pressure difference in both compressible and nearly incompressible irides.

  PublisherOA PDFDOI

Recent grants

• CAREER: Multi-scale Assessment of Biomechanical Alterations in Tricuspid Valves Following Pregnancy

  NSF · $496k · 2020–2025

• CAREER: Multi-scale Assessment of Biomechanical Alterations in Tricuspid Valves Following Pregnancy

  NSF · $400k · 2019–2020

• NIH Grant F32HL110651

  NIH · $101k · 2014

Frequent coauthors

• Syril Dorairaj

  Mayo Clinic in Florida

  32 shared

• Victor H. Barocas

  Twin Cities Orthopedics

  29 shared

• Anup Pant

  17 shared

• Samuel D. Salinas

  Universidad del Noreste

  17 shared

• Ayat Alni’mat

  16 shared

• Mo’ath AlShawabkeh

  Hashemite University

  16 shared

• Neda Rashidi

  Washington University in St. Louis

  14 shared

• Vineet S. Thomas

  Northeastern University

  13 shared

Labs

• Laboratory for Soft Tissue BiomechanicsPI

Education

• PhD, Biomedical Engineering

  Univeristy of Minnesota

  2010

• MS, Mechanical Engineering

  Northeastern University

  2005

• BS, Mechanical Engineering

  Sharif University of Technology

  2001

Awards & honors

• 2026 Community Advocate Award
• 2022 College of Engineering Faculty Fellow
• National Science Foundation CAREER Award