@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{kim_kasoji_durham_dayton_2022, title={Acoustic Hologram Lens Made of Nanoparticle-Epoxy Composite Molding for Directing Predefined Therapeutic Ultrasound Beams}, ISSN={["1948-5719"]}, DOI={10.1109/IUS54386.2022.9957379}, abstractNote={We present an acoustic hologram lens fabrication method for prototyping nondeformed hologram lenses with a tailored acoustic impedance. A pixelized hologram pattern is typically manufactured by photo-curing 3D printing methods, such as stereolithography (SLA) printing. However, SLA printing has major limitations for lens fabrication: vulnerability to deformation during photo-curing of a thin-plate shape lens structure and limited controllability of acoustic impedance. To overcome these limitations, we adopted a synthesized epoxy composite molding technique in this work. The used alumina nanoparticle (300 nm)-epoxy composite contains 22.5% alumina particles in volume. The characterized acoustic impedance of the composite was 4.68 MRayl whereas the conventional photopolymer exhibited 3.13 MRayl. We used these acoustic properties in lens modeling and acoustic hologram simulations. In simulations, the composite lens generated 145% pressure amplitude of the photopolymer lens due to improved acoustic impedance matching between a piezoelectric ceramic and water medium. We prototyped a composite lens through 1) 3D printing a lens cavity, 2) silicone rubber molding, and 3) epoxy composite lens molding. We observed no deformation of the prototyped composite lens whereas the photopolymer lens showed deformed edges. The beam mapping result using the composite lens showed 17% improved structural similarity with the designed pressure pattern compared to the photopolymer result. Due to the air bubbles trapped in a composite lens, the expected improvement of pressure amplitude over a photopolymer lens was not experimentally demonstrated. The additional degassing procedure will be included for future prototypes and pressure transmission will be evaluated.}, journal={2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS)}, author={Kim, Jinwook and Kasoji, Sandeep and Durham, Phillip G. and Dayton, Paul A.}, year={2022} }
 @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{kim_kasoji_durham_dayton_2021, title={Acoustic holograms for directing arbitrary cavitation patterns}, volume={118}, ISSN={["1077-3118"]}, DOI={10.1063/5.0035298}, abstractNote={Cavitation is an important phenomenon in biomedical acoustics. It can produce both desired outcomes (i.e., local therapeutic effects in vivo) and undesired outcomes (i.e., tissue damage), and it is, thus, important to both understand and direct cavitation fields. Through the use of three-dimensional-printed acoustic lenses and cavitation-sensitive acoustic phantoms, we demonstrate the generation of arbitrary shape two-dimensional (2D) microbubble cavitation fields. In this study, we demonstrate shaping a 1 MHz acoustic beam as the character “7” on a target plane that contains a higher mechanical index than the cavitation threshold for encapsulated microbubbles in a gelatin phantom. The lens pattern is first designed by calculating the phase map of the desired field using an angular spectrum approach. After lens implementation, acoustic pulsing through the lens generated the target acoustic field in a phantom and produced a cavitation map following the intended 2D pattern. The cavitation pattern was similar (with the structural similarity of 0.476) to the acoustic pressure map of the excitation beam.}, number={5}, journal={APPLIED PHYSICS LETTERS}, author={Kim, Jinwook and Kasoji, Sandeep and Durham, Phillip G. and Dayton, Paul A.}, year={2021}, month={Feb} }
 @article{nyankima_kasoji_cianciolo_dayton_chang_2019, title={Histological and blood chemistry examination of the rodent kidney after exposure to flash-replenishment ultrasound contrast imaging}, volume={98}, ISSN={["1874-9968"]}, DOI={10.1016/j.ultras.2019.05.003}, abstractNote={The purpose of this work is to investigate whether imaging sequences of flash-replenishment contrast enhanced ultrasound (CEUS) of the kidney result in chronic or acute bioeffects. Kidneys of female Fischer 344 rats were imaged using the flash-replenishment technique. Animals were separated into four groups (N = 31). Imaging was conducted with a 4C1 probe, driven by an Acuson Sequoia system with Definity microbubbles as the ultrasound contrast agent. During the flash phase of the imaging sequence, one kidney in each animal was exposed to either a mechanical index (MI) of 1.0 or 1.9. For each MI, half of the animals were sacrificed shortly after imaging (4 h) or after 2 weeks. A blinded veterinary nephropathologist reviewed the histopathology of both the imaged and control (non-imaged) kidney. Blood urea nitrogen (BUN) was measured for each animal prior to imaging and at the time of necropsy. Histopathology assessments in both the 1.0 and 1.9 MI groups revealed no signs of hemorrhage at either the 4-h or 2-week time point. BUN showed minor but statistically significant elevations in both the 1.0 and 1.9 MI groups, but no significant difference was present at the 2-week time point in the 1.0 MI group. All BUN levels (at both time points) remained in the normal range. In conclusion, CEUS with flash-replenishment imaging sequences did not result in kidney bioeffects observable with histology at early or late time points. Increases in BUN levels were observed after imaging, but were minimized when using a moderate MI (1.0).}, journal={ULTRASONICS}, author={Nyankima, A. Gloria and Kasoji, Sandeep and Cianciolo, Rachel and Dayton, Paul A. and Chang, Emily H.}, year={2019}, month={Sep}, pages={1–6} }
 @article{nyankima_kasoji_cianciolo_dayton_chang_2019, title={The biological response of rodent kidneys to low frequency, full volume diagnostic contrast-enhanced ultrasound imaging: Pilot data}, volume={25}, ISSN={["2352-3409"]}, DOI={10.1016/j.dib.2019.104170}, abstractNote={With the growth of contrast-enhanced ultrasound (CEUS) clinically, there are concerns about histologic bioeffects in regards to the implementation of high mechanical index (MI) imaging, such as the imaging sequence used for a specific CEUS technique known as flash-replenishment. The data presented are results from a pilot study, which explored flash-replenishment with high and moderate MI imaging sequences at time points of 24 hours and 2 weeks post imaging. This pilot study was followed by a larger study, which can be found in a journal article entitled “Histological and Blood Chemistry Examination of the Rodent Kidney After Exposure to Flash-Replenishment Ultrasound Contrast Imaging” Nyankima et al., 2019.}, journal={DATA IN BRIEF}, author={Nyankima, A. Gloria and Kasoji, Sandeep and Cianciolo, Rachel and Dayton, Paul A. and Chang, Emily H.}, year={2019}, month={Aug} }
 @article{li_kim_wang_kasoji_lindsey_dayton_jiang_2018, title={A Dual-Frequency Colinear Array for Acoustic Angiography in Prostate Cancer Evaluation}, volume={65}, ISSN={["1525-8955"]}, DOI={10.1109/TUFFC.2018.2872911}, abstractNote={Approximately 80% of men who reach 80 years of age will have some form of prostate cancer. The challenge remains to differentiate benign and malignant lesions. Based on recent research, acoustic angiography, a novel contrast-enhanced ultrasound imaging technique, can provide high-resolution visualization of tissue microvasculature and has demonstrated the ability to differentiate vascular characteristics between healthy and tumor tissue in preclinical studies. We hypothesize that transrectal acoustic angiography may enhance the assessment of prostate cancer. In this paper, we describe the development of a dual frequency, dual-layer colinear array transducer for transrectal acoustic angiography. The probe consists of 64 transmitting (TX) elements with a center frequency of 3 MHz and 128 receiving (RX) elements with a center frequency of 15 MHz. The dimensions of the array are 18 mm in azimuth and 9 mm in elevation. The pitch is  $280~\mu \text{m}$  for TX elements and 140  $\mu \text{m}$  for RX elements. Pulse-echo tests of TX/RX elements and aperture acoustic field measurements were conducted, and both results were compared with the simulation results. Real-time contrast imaging was performed using a Verasonics system and a tissue-mimicking phantom. Nonlinear acoustic responses from microbubble contrast agents at a depth of 35 mm were clearly observed. In vivo imaging in a rodent model demonstrated the ability to detect individual vessels underneath the skin. These results indicate the potential use of the array described herein for acoustic angiography imaging of prostate tumor and identification of regions of neovascularization for the guidance of prostate biopsies.}, number={12}, journal={IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL}, author={Li, Sibo and Kim, Jinwook and Wang, Zhuochen and Kasoji, Sandeep and Lindsey, Brooks D. and Dayton, Paul A. and Jiang, Xiaoning}, year={2018}, month={Dec}, pages={2418–2428} }
 @article{kasoji_chang_mullin_chong_rathmell_dayton_2017, title={A Pilot Clinical Study in Characterization of Malignant Renal-cell Carcinoma Subtype with Contrast-enhanced Ultrasound}, volume={39}, ISSN={["1096-0910"]}, DOI={10.1177/0161734616666383}, abstractNote={ Malignant renal cell carcinoma (RCC) is a diverse set of diseases, which are independently difficult to characterize using conventional MRI and CT protocols due to low temporal resolution to study perfusion characteristics. Because different disease subtypes have different prognoses and involve varying treatment regimens, the ability to determine RCC subtype non-invasively is a clinical need. Contrast-enhanced ultrasound (CEUS) has been assessed as a tool to characterize kidney lesions based on qualitative and quantitative assessment of perfusion patterns, and we hypothesize that this technique might help differentiate disease subtypes. Twelve patients with RCC confirmed pathologically were imaged using contrast-enhanced ultrasound. Time intensity curves were generated and analyzed quantitatively using 10 characteristic metrics. Results showed that peak intensity ( p = 0.001) and time-to-80% on wash-out ( p = 0.004) provided significant differences between clear cell, papillary, and chromophobe RCC subtypes. These results suggest that CEUS may be a feasible test for characterizing RCC subtypes. }, number={2}, journal={ULTRASONIC IMAGING}, author={Kasoji, Sandeep K. and Chang, Emily H. and Mullin, Lee B. and Chong, Wui K. and Rathmell, W. Kimryn and Dayton, Paul A.}, year={2017}, month={Mar}, pages={126–136} }
 @inproceedings{li_kim_wang_jiang_kasoji_lindsey_dayton_2016, title={A dual-frequency co-linear array for prostate acoustic angiography}, DOI={10.1109/ultsym.2016.7728718}, abstractNote={Approximately 80% of men who reach 80-years of age will have some form of prostate cancer. The challenge remains to differentiate indolent from aggressive disease. Based on recent research, acoustic angiography, a novel contrast enhanced ultrasound imaging technique, can provide high-resolution visualization of tissue microvasculature and has demonstrated the ability to differentiate vascular characteristics between healthy and tumor tissue. We hypothesize that transrectal acoustic angiography may enhance assessment of prostate cancer. In this paper, we describe the development of a dual layer co-linear array ultrasound transducer for transrectal acoustic angiography. The KLM model and Field II were used for the element design and acoustic field simulation, respectively. The probe consists of 64 transmit elements with a center frequency of 3 MHz and 128 receive elements with a center frequency of 15 MHz. The dimensions of the array are 18 mm in azimuth and 8 mm in elevation. The pitch is 280 μm for transmitting (TX) elements and 140 μm for receiving (RX) elements. Pulse-echo test of TX/RX elements were conducted and compared with the simulation results. Real-time contrast imaging was tested using a Verasonics system. Non-linear responses from microbubble contrast agents at a depth of 18 mm were clearly observed. The axial beam width (-6 dB) and CTR were calculated from the measured signals to be 400 μm and 20 dB, respectively. These results suggest that the prototype co-linear array is capable of performing dual-frequency superharmonic imaging of microbubbles for prostate cancer assessment.}, booktitle={2016 ieee international ultrasonics symposium (ius)}, author={Li, S. B. and Kim, J. and Wang, Z. C. and Jiang, X. N. and Kasoji, S. and Lindsey, B. and Dayton, P. A.}, year={2016} }
 @article{kasoji_pattenden_malc_jayakody_tsuruta_mieczkowski_janzen_dayton_2015, title={Cavitation Enhancing Nanodroplets Mediate Efficient DNA Fragmentation in a Bench Top Ultrasonic Water Bath}, volume={10}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0133014}, abstractNote={A perfluorocarbon nanodroplet formulation is shown to be an effective cavitation enhancement agent, enabling rapid and consistent fragmentation of genomic DNA in a standard ultrasonic water bath. This nanodroplet-enhanced method produces genomic DNA libraries and next-generation sequencing results indistinguishable from DNA samples fragmented in dedicated commercial acoustic sonication equipment, and with higher throughput. This technique thus enables widespread access to fast bench-top genomic DNA fragmentation.}, number={7}, journal={PLOS ONE}, author={Kasoji, Sandeep K. and Pattenden, Samantha G. and Malc, Ewa P. and Jayakody, Chatura N. and Tsuruta, James K. and Mieczkowski, Piotr A. and Janzen, William P. and Dayton, Paul A.}, year={2015}, month={Jul} }
 @article{kim_li_kasoji_dayton_jiang_2015, title={Dual-frequency Super Harmonic Imaging Piezoelectric Transducers for Transrectal Ultrasound}, volume={9438}, ISSN={["0277-786X"]}, DOI={10.1117/12.2084459}, abstractNote={In this paper, a 2/14 MHz dual-frequency single-element transducer and a 2/22 MHz sub-array (16/48-elements linear array) transducer were developed for contrast enhanced super-harmonic ultrasound imaging of prostate cancer with the low frequency ultrasound transducer as a transmitter for contrast agent (microbubble) excitation and the high frequency transducer as a receiver for detection of nonlinear responses from microbubbles. The 1-3 piezoelectric composite was used as active materials of the single-element transducers due to its low acoustic impedance and high coupling factor. A high dielectric constant PZT ceramic was used for the sub-array transducer due to its high dielectric property induced relatively low electrical impedance. The possible resonance modes of the active elements were estimated using finite element analysis (FEA). The pulse-echo response, peak-negative pressure and bubble response were tested, followed by in vitro contrast imaging tests using a graphite-gelatin tissue-mimicking phantom. The single-element dual frequency transducer (8 × 4 × 2 mm3) showed a -6 dB fractional bandwidth of 56.5% for the transmitter, and 41.8% for the receiver. A 2 MHz-transmitter (730 μm pitch and 6.5 mm elevation aperture) and a 22 MHz-receiver (240 μm pitch and 1.5 mm aperture) of the sub-array transducer exhibited -6 dB fractional bandwidth of 51.0% and 40.2%, respectively. The peak negative pressure at the far field was about -1.3 MPa with 200 Vpp, 1-cycle 2 MHz burst, which is high enough to excite microbubbles for nonlinear responses. The 7th harmonic responses from micro bubbles were successfully detected in the phantom imaging test showing a contrast-to-tissue ratio (CTR) of 16 dB.}, journal={HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS 2015}, author={Kim, Jinwook and Li, Sibo and Kasoji, Sandeep and Dayton, Paul A. and Jiang, Xiaoning}, year={2015} }
 @article{kim_li_kasoji_dayton_jiang_2015, title={Phantom evaluation of stacked-type dual-frequency 1-3 composite transducers: A feasibility study on intracavitary acoustic angiography}, volume={63}, ISSN={["1874-9968"]}, DOI={10.1016/j.ultras.2015.06.009}, abstractNote={In this paper, we present phantom evaluation results of a stacked-type dual-frequency 1-3 piezoelectric composite transducer as a feasibility study for intracavitary acoustic angiography. Our previous design (6.5/30 MHz PMN-PT single crystal transducer) for intravascular contrast ultrasound imaging exhibited a contrast-to-tissue ratio (CTR) of 12 dB with a penetration depth of 2.5 mm. For improved penetration depth (>3 mm) and comparable contrast-to-tissue ratio (>12 dB), we evaluated a lower frequency 2/14 MHz PZT 1-3 composite transducer. Superharmonic imaging performance of this transducer and a detailed characterization of key parameters for acoustic angiography are presented. The 2/14 MHz arrangement demonstrated a -6 dB fractional bandwidth of 56.5% for the transmitter and 41.8% for the receiver, and produced sufficient peak-negative pressures (>1.5 MPa) at 2 MHz to induce a strong nonlinear harmonic response from microbubble contrast agents. In an in-vitro contrast ultrasound study using a tissue mimicking phantom and 200 μm cellulose microvessels, higher harmonic microbubble responses, from the 5th through the 7th harmonics, were detected with a signal-to-noise ratio of 16 dB. The microvessels were resolved in a two-dimensional image with a -6dB axial resolution of 615 μm (5.5 times the wavelength of 14 MHz waves) and a contrast-to-tissue ratio of 16 dB. This feasibility study, including detailed explanation of phantom evaluation and characterization procedures for key parameters, will be useful for the development of future dual-frequency array transducers for intracavitary acoustic angiography.}, journal={ULTRASONICS}, author={Kim, Jinwook and Li, Sibo and Kasoji, Sandeep and Dayton, Paul A. and Jiang, Xiaoning}, year={2015}, month={Dec}, pages={7–15} }