@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={
            Background
            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.
          }, 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{czernuszewicz_aji_moore_montgomery_velasco_torres_anand_johnson_deal_zuki_et al._2022, title={Development of a Robotic Shear Wave Elastography System for Noninvasive Staging of Liver Disease in Murine Models}, ISSN={["2471-254X"]}, DOI={10.1002/hep4.1912}, abstractNote={Shear wave elastography (SWE) is an ultrasound‐based stiffness quantification technology that is used for noninvasive liver fibrosis assessment. However, despite widescale clinical adoption, SWE is largely unused by preclinical researchers and drug developers for studies of liver disease progression in small animal models due to significant experimental, technical, and reproducibility challenges. Therefore, the aim of this work was to develop a tool designed specifically for assessing liver stiffness and echogenicity in small animals to better enable longitudinal preclinical studies. A high‐frequency linear array transducer (12‐24 MHz) was integrated into a robotic small animal ultrasound system (Vega; SonoVol, Inc., Durham, NC) to perform liver stiffness and echogenicity measurements in three dimensions. The instrument was validated with tissue‐mimicking phantoms and a mouse model of nonalcoholic steatohepatitis. Female C57BL/6J mice (n = 40) were placed on choline‐deficient, L‐amino acid‐defined, high‐fat diet and imaged longitudinally for 15 weeks. A subset was sacrificed after each imaging timepoint (n = 5) for histological validation, and analyses of receiver operating characteristic (ROC) curves were performed. Results demonstrated that robotic measurements of echogenicity and stiffness were most strongly correlated with macrovesicular steatosis (R2 = 0.891) and fibrosis (R2 = 0.839), respectively. For diagnostic classification of fibrosis (Ishak score), areas under ROC (AUROCs) curves were 0.969 for ≥Ishak1, 0.984 for ≥Ishak2, 0.980 for ≥Ishak3, and 0.969 for ≥Ishak4. For classification of macrovesicular steatosis (S‐score), AUROCs were 1.00 for ≥S2 and 0.997 for ≥S3. Average scanning and analysis time was <5 minutes/liver. Conclusion: Robotic SWE in small animals is feasible and sensitive to small changes in liver disease state, facilitating in vivo staging of rodent liver disease with minimal sonographic expertise.}, journal={HEPATOLOGY COMMUNICATIONS}, author={Czernuszewicz, Tomasz J. and Aji, Adam M. and Moore, Christopher J. and Montgomery, Stephanie A. and Velasco, Brian and Torres, Gabriela and Anand, Keerthi S. and Johnson, Kennita A. and Deal, Allison M. and Zuki, Dzenan and et al.}, year={2022}, month={Feb} }