@article{alhmoud_walmer_kavanagh_chang_johnson_bikdash_2023, title={CLASSIFYING KIDNEY DISEASE IN A VERVET MODEL USING SPATIALLY ENCODED CONTRAST-ENHANCED ULTRASOUND PERFUSION PARAMETERS}, volume={49}, ISSN={["1879-291X"]}, DOI={10.1016/j.ultrasmedbio.2022.10.015}, abstractNote={Early stages of diabetic kidney disease (DKD) are difficult to diagnose in patients with type 2 diabetes. This work was aimed at identifying contrast-enhanced ultrasound (CEUS) perfusion parameters, a microcirculatory biomarker indicative of early DKD progression. CEUS kidney flash-replenishment data were acquired in control, insulin resistant and diabetic vervet monkeys (N = 16). By use of a mono-exponential model, time-intensity curve parameters related to blood volume (A), velocity (β) and flow rate (perfusion index [PI]) were extracted from 10 concentric kidney layers to study spatial perfusion patterns that could serve as strong indicators of disease. Mean squared error (MSE) was used to assess model performance. Features calculated from the perfusion parameters were inputs for the linear regression models to determine which features could distinguish between cohorts. The mono-exponential model performed well, with average MSEs (±standard deviation) of 0.0254 (±0.0210), 0.0321 (±0.0242) and 0.0287 (±0.0130) for the control, insulin resistant and diabetic cohorts, respectively. Perfusion index features, with blood pressure, were the best classifiers between cohorts (p < 0.05). CEUS has the potential to detect early microvascular changes, providing insight into disease-related structural changes in the kidney. The sensitivity of this technique should be explored further by assessing various stages of DKD.}, number={3}, journal={ULTRASOUND IN MEDICINE AND BIOLOGY}, author={Alhmoud, Issa W. and Walmer, Rachel W. and Kavanagh, Kylie and Chang, Emily H. and Johnson, Kennita A. and Bikdash, Marwan}, year={2023}, month={Mar}, pages={761–772} }
 @article{walmer_ritter_sridharan_kasoji_altun_lee_olinger_wagner_radhakrishna_johnson_et al._2023, title={The Performance of Flash Replenishment Contrast-Enhanced Ultrasound for the Qualitative Assessment of Kidney Lesions in Patients with Chronic Kidney Disease}, volume={12}, ISSN={["2077-0383"]}, DOI={10.3390/jcm12206494}, abstractNote={We investigated the accuracy of CEUS for characterizing cystic and solid kidney lesions in patients with chronic kidney disease (CKD). Cystic lesions are assessed using Bosniak criteria for computed tomography (CT) and magnetic resonance imaging (MRI); however, in patients with moderate to severe kidney disease, CT and MRI contrast agents may be contraindicated. Contrast-enhanced ultrasound (CEUS) is a safe alternative for characterizing these lesions, but data on its performance among CKD patients are limited. We performed flash replenishment CEUS in 60 CKD patients (73 lesions). Final analysis included 53 patients (63 lesions). Four readers, blinded to true diagnosis, interpreted each lesion. Reader evaluations were compared to true lesion classifications. Performance metrics were calculated to assess malignant and benign diagnoses. Reader agreement was evaluated using Bowker’s symmetry test. Combined reader sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for diagnosing malignant lesions were 71%, 75%, 45%, and 90%, respectively. Sensitivity (81%) and specificity (83%) were highest in CKD IV/V patients when grouped by CKD stage. Combined reader sensitivity, specificity, PPV, and NPV for diagnosing benign lesions were 70%, 86%, 91%, and 61%, respectively. Again, in CKD IV/V patients, sensitivity (81%), specificity (95%), and PPV (98%) were highest. Inter-reader diagnostic agreement varied from 72% to 90%. In CKD patients, CEUS is a potential low-risk option for screening kidney lesions. CEUS may be particularly beneficial for CKD IV/V patients, where kidney preservation techniques are highly relevant.}, number={20}, journal={JOURNAL OF CLINICAL MEDICINE}, author={Walmer, Rachel W. and Ritter, Victor S. and Sridharan, Anush and Kasoji, Sandeep K. and Altun, Ersan and Lee, Ellie and Olinger, Kristen and Wagner, Sean and Radhakrishna, Roshni and Johnson, Kennita A. and et al.}, year={2023}, month={Oct} }
 @article{srivastava_sridharan_walmer_kasoji_burke_dayton_johnson_chang_2022, title={Association of Contrast-Enhanced Ultrasound-Derived Kidney Cortical Microvascular Perfusion with Kidney Function}, volume={3}, ISSN={["2641-7650"]}, DOI={10.34067/KID.0005452021}, abstractNote={Individuals with chronic kidney disease (CKD) have decreased kidney cortical microvascular perfusion, which may lead to worsening kidney function over time, but methods to quantify kidney cortical microvascular perfusion are not feasible to incorporate into clinical practice. Contrast-enhanced ultrasound (CEUS) may quantify kidney cortical microvascular perfusion, which requires further investigation in individuals across the spectrum of kidney function.We performed CEUS on a native kidney of 83 individuals across the spectrum of kidney function and calculated quantitative CEUS-derived kidney cortical microvascular perfusion biomarkers. Participants had a continuous infusion of the microbubble contrast agent (Definity) with a flash-replenishment sequence during their CEUS scan. Lower values of the microbubble velocity (β) and perfusion index (β×A) may represent lower kidney cortical microvascular perfusion. Multivariable linear regression models tested the associations of the microbubble velocity (β) and perfusion index (β×A) with estimated glomerular filtration rate (eGFR).Thirty-eight individuals with CKD (mean age±SD 65.2±12.6 years, median [IQR] eGFR 31.5 [18.9-41.5] ml/min per 1.73 m2), 37 individuals with end stage kidney disease (ESKD; age 54.8±12.3 years), and eight healthy volunteers (age 44.1±15.0 years, eGFR 117 [106-120] ml/min per 1.73 m2) underwent CEUS without side effects. Individuals with ESKD had the lowest microbubble velocity (β) and perfusion index (β×A) compared with individuals with CKD and healthy volunteers. The microbubble velocity (β) and perfusion index (β×A) had moderate positive correlations with eGFR (β: rs=0.44, P<0.001; β×A: rs=0.50, P<0.001). After multivariable adjustment, microbubble velocity (β) and perfusion index (β×A) remained significantly associated with eGFR (change in natural log transformed eGFR per 1 unit increase in natural log transformed biomarker: β, 0.38 [95%, CI 0.17 to 0.59]; β×A, 0.79 [95% CI, 0.45 to 1.13]).CEUS-derived kidney cortical microvascular perfusion biomarkers are associated with eGFR. Future studies are needed to determine if CEUS-derived kidney cortical microvascular perfusion biomarkers have prognostic value.}, number={4}, journal={KIDNEY360}, author={Srivastava, Anand and Sridharan, Anush and Walmer, Rachel W. and Kasoji, Sandeep K. and Burke, Lauren M. B. and Dayton, Paul A. and Johnson, Kennita A. and Chang, Emily H.}, year={2022}, month={Apr}, pages={647–656} }
 @article{marvin_ding_white_orlova_wang_zywot_vickerman_harr_tarrant_dayton_et al._2019, title={On Command Drug Delivery via Cell-Conveyed Phototherapeutics}, volume={15}, ISSN={["1613-6829"]}, DOI={10.1002/smll.201901442}, abstractNote={Herein, the use of red blood cells (RBCs) as carriers of cytoplasmically interned phototherapeutic agents is described. Photolysis promotes drug release from the RBC carrier thereby providing the means to target specific diseased sites. This strategy is realized with a vitamin B12-taxane conjugate (B12-TAX), in which the drug is linked to the vitamin via a photolabile CoC bond. The conjugate is introduced into mouse RBCs (mRBCs) via a pore-forming/pore-resealing procedure and is cytoplasmically retained due to the membrane impermeability of B12. Photolysis separates the taxane from the B12 cytoplasmic anchor, enabling the drug to exit the RBC carrier. A covalently appended Cy5 antenna sensitizes the conjugate (Cy5-B12-TAX) to far red light, thereby circumventing the intense light absorbing properties of hemoglobin (350-600 nm). Microscopy and imaging flow cytometry reveal that Cy5-B12-TAX-loaded mRBCs act as drug carriers. Furthermore, intravital imaging of mice furnish a real time assessment of circulating phototherapeutic-loaded mRBCs as well as evidence of the targeted photorelease of the taxane upon photolysis. Histopathology confirms that drug release occurs in a well resolved spatiotemporal fashion. Finally, acoustic angiography is employed to assess the consequences of taxane release at the tumor site in Nu/Nu-tumor-bearing mice.}, number={37}, journal={SMALL}, author={Marvin, Christina M. and Ding, Song and White, Rachel E. and Orlova, Natalia and Wang, Qunzhao and Zywot, Emilia M. and Vickerman, Brianna M. and Harr, Lauren and Tarrant, Teresa K. and Dayton, Paul A. and et al.}, year={2019}, month={Sep} }