Fikunwa Kolawole

All Publications

• Ex-vivo functional and mechanical assessment of human endopelvic fascia in men undergoing radical prostatectomy. World journal of urology Abdalla, A. S., Chen, H., Kolawole, F. O., Nolley, R., Kao, C. S., Dobberfuhl, A. D., Gill, H. S. 2025; 43 (1): 209

  Abstract

  There are limited studies describing the contractile function of the endopelvic fascia in the male pelvis and the role of the endopelvic fascia in the pathophysiology of lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). We performed ex-vivo functional studies and described the histology of the endopelvic fascia.Endopelvic fascia specimens were collected from patients (n = 10) undergoing robotic prostatectomy. Two fascia strips (2 × 1 cm) from each side of the pelvis were excised and immediately used for functional studies. Each strip was cut into one centimeter piece for studying. One strip was suspended in organ baths and contractile response to potassium chloride (100 mM), and carbachol (0.01 µM, 1 µM, 10 µM, 20 µM) assessed. The second strip was used for histology with hematoxylin and eosin (H&E) and Masson-trichrome staining for elastic fibers, collagen and smooth muscle or stress strain testing.Twenty endopelvic fascia samples from 10 patients were analyzed. Only two specimens showed a contractile response to potassium chloride. The remaining 18 specimens exhibited no contractile response. Histologically, the fascia consisted mainly of fibrous connective tissue with minor adipose tissue and occasional smooth muscle, along with arterioles. Tensile testing revealed nonlinear behavior, with a nominal stiffness estimated at 0.765 MPa after the toe region.The male endopelvic fascia lacks contractile response to potassium chloride and cholinergic stimulation, resembling other human fasciae histologically. It's improbable that it contributes to male LUTS but may impede prostate expansion mechanically due to its fibrous nature.

  View details for DOI 10.1007/s00345-025-05578-5

  View details for PubMedID 40178628

  View details for PubMedCentralID 1472875

• Characterizing variability in passive myocardial stiffness in healthy human left ventricles using personalized MRI and finite element modeling. Scientific reports Kolawole, F. O., Wang, V. Y., Freytag, B., Loecher, M., Cork, T. E., Nash, M. P., Kuhl, E., Ennis, D. B. 2025; 15 (1): 5556

  Abstract

  Abnormal passive stiffness of the heart muscle (myocardium) is evident in the pathophysiology of several cardiovascular diseases, making it an important indicator of heart health. Recent advancements in cardiac imaging and biophysical modeling now enable more effective evaluation of this biomarker. Estimating passive myocardial stiffness can be accomplished through an MRI-based approach that requires comprehensive subject-specific input data. This includes the gross cardiac geometry (e.g. from conventional cine imaging), regional diastolic kinematics (e.g. from tagged MRI), microstructural configuration (e.g. from diffusion tensor imaging), and ventricular diastolic pressure, whether invasively measured or non-invasively estimated. Despite the progress in cardiac biomechanics simulations, developing a framework to integrate multiphase and multimodal cardiac MRI data for estimating passive myocardial stiffness has remained a challenge. Moreover, the sensitivity of estimated passive myocardial stiffness to input data has not been fully explored. This study aims to: (1) develop a framework for integrating subject-specific in vivo MRI data into in silico left ventricular finite element models to estimate passive myocardial stiffness, (2) apply the framework to estimate the passive myocardial stiffness of multiple healthy subjects under assumed filling pressure, and (3) assess the sensitivity of these estimates to loading conditions and myofiber orientations. This work contributes toward the establishment of a range of reference values for material parameters of passive myocardium in healthy human subjects. Notably, in this study, beat-to-beat variation in left ventricular end-diastolic pressure was found to have a greater influence on passive myocardial material parameter estimation than variation in fiber orientation.

  View details for DOI 10.1038/s41598-025-89243-2

  View details for PubMedID 39953070

  View details for PubMedCentralID PMC11829060

• Validating MRI-Derived Myocardial Stiffness Estimates Using In Vitro Synthetic Heart Models. Annals of biomedical engineering Kolawole, F. O., Peirlinck, M., Cork, T. E., Levenston, M., Kuhl, E., Ennis, D. B. 2023

  Abstract

  Impaired cardiac filling in response to increased passive myocardial stiffness contributes to the pathophysiology of heart failure. By leveraging cardiac MRI data and ventricular pressure measurements, we can estimate in vivo passive myocardial stiffness using personalized inverse finite element models. While it is well-known that this approach is subject to uncertainties, only few studies quantify the accuracy of these stiffness estimates. This lack of validation is, at least in part, due to the absence of ground truth in vivo passive myocardial stiffness values. Here, using 3D printing, we created soft, homogenous, isotropic, hyperelastic heart phantoms of varying geometry and stiffness and simulate diastolic filling by incorporating the phantoms into an MRI-compatible left ventricular inflation system. We estimate phantom stiffness from MRI and pressure data using inverse finite element analyses based on a Neo-Hookean model. We demonstrate that our identified softest and stiffest values of 215.7 and 512.3kPa agree well with the ground truth of 226.2 and 526.4kPa. Overall, our estimated stiffnesses revealed a good agreement with the ground truth ([Formula: see text] error) across all models. Our results suggest that MRI-driven computational constitutive modeling can accurately estimate synthetic heart material stiffnesses in the range of 200-500kPa.

  View details for DOI 10.1007/s10439-023-03164-7

  View details for PubMedID 36914919

• On the impact of vessel wall stiffness on quantitative flow dynamics in a synthetic model of the thoracic aorta. Scientific reports Zimmermann, J. n., Loecher, M. n., Kolawole, F. O., Bäumler, K. n., Gifford, K. n., Dual, S. A., Levenston, M. n., Marsden, A. L., Ennis, D. B. 2021; 11 (1): 6703

  Abstract

  Aortic wall stiffening is a predictive marker for morbidity in hypertensive patients. Arterial pulse wave velocity (PWV) correlates with the level of stiffness and can be derived using non-invasive 4D-flow magnetic resonance imaging (MRI). The objectives of this study were twofold: to develop subject-specific thoracic aorta models embedded into an MRI-compatible flow circuit operating under controlled physiological conditions; and to evaluate how a range of aortic wall stiffness impacts 4D-flow-based quantification of hemodynamics, particularly PWV. Three aorta models were 3D-printed using a novel photopolymer material at two compliant and one nearly rigid stiffnesses and characterized via tensile testing. Luminal pressure and 4D-flow MRI data were acquired for each model and cross-sectional net flow, peak velocities, and PWV were measured. In addition, the confounding effect of temporal resolution on all metrics was evaluated. Stiffer models resulted in increased systolic pressures (112, 116, and 133 mmHg), variations in velocity patterns, and increased peak velocities, peak flow rate, and PWV (5.8-7.3 m/s). Lower temporal resolution (20 ms down to 62.5 ms per image frame) impacted estimates of peak velocity and PWV (7.31 down to 4.77 m/s). Using compliant aorta models is essential to produce realistic flow dynamics and conditions that recapitulated in vivo hemodynamics.

  View details for DOI 10.1038/s41598-021-86174-6

  View details for PubMedID 33758315

• Quantitative Hemodynamics in Aortic Dissection: Comparing in Vitro MRI with FSI Simulation in a Compliant Model Functional Imaging and Modeling of the Heart Zimmermann, J., Loecher, M., Kolawole, F., Baumler, K., Gifford, K., Dual, S. A., Levenston, M. E., Marsden, A., Ennis, D. B. 2021: 575–586

  View details for DOI 10.1007/978-3-030-78710-3_55

• A Framework for Evaluating Myocardial Stiffness Using 3D-Printed Heart Phantoms Functional Imaging and Modeling of the Heart Kolawole, F., Peirlinck, M., Cork, T. E., Wang, V. Y., Dual, S. A., Levenston, M. E., Kuhl, E., Ennis, D. B. 2021: 305-314

  View details for DOI 10.1007/978-3-030-78710-3_30

• Miniature Diamond-Based Fiber Optic Pressure Sensor with Dual Polymer-Ceramic Adhesives SENSORS Bae, H., Giri, A., Kolawole, O., Azimi, A., Jackson, A., Harris, G. 2019; 19 (9)

  Abstract

  Diamond is a good candidate for harsh environment sensing due to its high melting temperature, Young's modulus, and thermal conductivity. A sensor made of diamond will be even more promising when combined with some advantages of optical sensing (i.e., EMI inertness, high temperature operation, and miniaturization). We present a miniature diamond-based fiber optic pressure sensor fabricated using dual polymer-ceramic adhesives. The UV curable polymer and the heat-curing ceramic adhesive are employed for easy and reliable optical fiber mounting. The usage of the two different adhesives considerably improves the manufacturability and linearity of the sensor, while significantly decreasing the error from the temperature cross-sensitivity. Experimental study shows that the sensor exhibits good linearity over a pressure range of 2.0-9.5 psi with a sensitivity of 18.5 nm/psi (R2 = 0.9979). Around 275 °C of working temperature was achieved by using polymer/ceramic dual adhesives. The sensor can benefit many fronts that require miniature, low-cost, and high-accuracy sensors including biomedical and industrial applications. With an added antioxidation layer on the diamond diaphragm, the sensor can also be applied for harsh environment applications due to the high melting temperature and Young's modulus of the material.

  View details for DOI 10.3390/s19092202

  View details for Web of Science ID 000469766800246

  View details for PubMedID 31086036

  View details for PubMedCentralID PMC6539731