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Nyankima AG, Kasoji S, Cianciolo R, Dayton PA, Chang EH. Histological and blood chemistry examination of the rodent kidney after exposure to flash-replenishment ultrasound contrast imaging. ULTRASONICS 2019; 98:1-6. [PMID: 31121515 PMCID: PMC6710155 DOI: 10.1016/j.ultras.2019.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/28/2019] [Accepted: 05/09/2019] [Indexed: 05/12/2023]
Abstract
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).
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Affiliation(s)
- A Gloria Nyankima
- Joint Department of Biomedical Engineering, University of North Carolina Chapel Hill and North Carolina State University, Chapel Hill, NC, USA
| | - Sandeep Kasoji
- Joint Department of Biomedical Engineering, University of North Carolina Chapel Hill and North Carolina State University, Chapel Hill, NC, USA
| | - Rachel Cianciolo
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, USA
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina Chapel Hill and North Carolina State University, Chapel Hill, NC, USA
| | - Emily H Chang
- UNC Kidney Center and Division of Nephrology & Hypertension, University of North Carolina Chapel Hill, Chapel Hill, NC, USA.
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Nyankima AG, Rojas JD, Cianciolo R, Johnson KA, Dayton PA. In Vivo Assessment of the Potential for Renal Bio-Effects from the Vaporization of Perfluorocarbon Phase-Change Contrast Agents. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:368-376. [PMID: 29254872 DOI: 10.1016/j.ultrasmedbio.2017.10.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 10/12/2017] [Accepted: 10/30/2017] [Indexed: 06/07/2023]
Abstract
Low-boiling-point perfluorocarbon phase-change contrast agents (PCCAs) provide an alternative to microbubble contrast agents. Although parameter ranges related to in vivo bio-effects of microbubbles are fairly well characterized, few studies have been done to evaluate the potential of bio-effects related to PCCAs. To bridge this gap, we present an assessment of biological effects (e.g., hemorrhage) related to acoustically excited PCCAs in the rodent kidney. The presence or absence of bio-effects was observed after sonication with various perfluorocarbon core PCCAs (decafluorobutane, octafluoropropane or a 1:1 mixture) and as a function of activation pulse mechanical index (MI; minimum activation threshold, which was a moderate MI of 0.81-1.35 vs. a clinical maximum of 1.9). Bio-effects on renal tissue were assessed through hematology and histology including measurement of blood creatinine levels and the quantity of red blood cell (RBC) casts present in hematoxylin and eosin-stained kidney tissue sections after sonication. Short-term (24 h) and long-term (2 and 4 wk) analyses were performed after treatment. Results indicated that bio-effects from PCCA vaporization were not observed at lower mechanical indices. At higher mechanical indices, bio-effects were observed at 24 h, although these were not observable 2 wk after treatment.
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Affiliation(s)
- A Gloria Nyankima
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Juan D Rojas
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Rachel Cianciolo
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Kennita A Johnson
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, USA.
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Miller DL, Dou C, Lu X, Zhu YI, Fabiilli ML, Owens GE, Kripfgans OD. Use of Theranostic Strategies in Myocardial Cavitation-Enabled Therapy. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:1865-75. [PMID: 25890888 PMCID: PMC4461496 DOI: 10.1016/j.ultrasmedbio.2015.03.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 02/27/2015] [Accepted: 03/12/2015] [Indexed: 05/04/2023]
Abstract
The accumulation of microlesions induced by ultrasound interaction with contrast microbubbles in the myocardium potentially represents a new method of tissue reduction therapy. Anesthetized rats were treated in a heated water bath with 1.5-MHz focused ultrasound pulses triggered once every four heartbeats from the electrocardiogram during infusion of microbubble contrast agent. Treatment was guided by an 8-MHz B-mode imaging transducer, which also was used to provide estimates of left ventricular echogenicity as a possible predictor of efficacy during treatment. Strategies to reduce prospective clinical treatment durations were tested, including pulse modulation to simulate a theranostic scanning strategy and an increased agent infusion rate over shorter durations. Sources of variability, including ultrasound path variation and venous catheter placement, also were investigated. Electrocardiographic premature complexes were monitored, and Evans-blue stained cardiomyocyte scores were obtained from frozen sections. Left ventricular echogenicity reflected variations in the infused microbubble concentration, but failed to predict efficacy. Comparison of suspensions of varied microbubble size revealed that left ventricular echogenicity was dominated by larger bubbles, whereas efficacy appeared to be dependent on smaller sizes. Simulated scanning was as effective as the normal fixed-beam treatment, and high agent infusion allowed reduced treatment duration. The success of these theranostic strategies may increase the prospects for realistic clinical translation of myocardial cavitation-enabled therapy.
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Affiliation(s)
- Douglas L Miller
- Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan, USA.
| | - Chunyan Dou
- Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Xiaofang Lu
- Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Yiying I Zhu
- Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Mario L Fabiilli
- Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Gabe E Owens
- Department of Pediatrics and Communicable Diseases, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Oliver D Kripfgans
- Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan, USA
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Miller DL, Dou C, Owens GE, Kripfgans OD. Optimization of ultrasound parameters of myocardial cavitation microlesions for therapeutic application. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:1228-36. [PMID: 24613640 PMCID: PMC4011951 DOI: 10.1016/j.ultrasmedbio.2014.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 11/25/2013] [Accepted: 01/02/2014] [Indexed: 05/11/2023]
Abstract
Intermittent high intensity ultrasound scanning with contrast microbubbles can induce scattered cavitation microlesions in the myocardium, which may be of value for tissue reduction therapy. Anesthetized rats were treated in a heated water bath with 1.5 MHz focused ultrasound pulses, guided by an 8 MHz imaging transducer. The relative efficacy with 2 or 4 MPa pulses, 1:4 or 1:8 trigger intervals and 5 or 10 cycle pulses was explored in six groups. Electrocardiogram premature complexes (PCs) induced by the triggered pulse bursts were counted, and Evans blue stained cardiomyocyte scores (SCSs) were obtained. The increase from 2 to 4 MPa produced significant increases in PCs and SCSs and eliminated an anticipated decline in the rate of PC induction with time, which might hinder therapeutic efficacy. Increased intervals and pulse durations did not yield significant increases in the effects. The results suggest that cavitation microlesion production can be refined and potentially lead to a clinically robust therapeutic method.
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Affiliation(s)
- Douglas L Miller
- Department of Radiology, University of Michigan Health System, Ann Arbor, MI, USA.
| | - Chunyan Dou
- Department of Radiology, University of Michigan Health System, Ann Arbor, MI, USA
| | - Gabe E Owens
- Department of Pediatrics, University of Michigan Health System, Ann Arbor, MI, USA
| | - Oliver D Kripfgans
- Department of Radiology, University of Michigan Health System, Ann Arbor, MI, USA
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Johnson K, Cianciolo R, Gessner RC, Dayton PA. A pilot study to assess markers of renal damage in the rodent kidney after exposure to 7 MHz ultrasound pulse sequences designed to cause microbubble translation and disruption. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:168-72. [PMID: 22104535 PMCID: PMC3822907 DOI: 10.1016/j.ultrasmedbio.2011.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 10/03/2011] [Accepted: 10/04/2011] [Indexed: 05/09/2023]
Abstract
Acoustic radiation force has been proposed as a mechanism to enhance microbubble concentration for therapeutic and molecular imaging applications. It is hypothesized that once microbubbles are localized, bursting them with acoustic pressure could result in local drug delivery. It is known that low-frequency, high-amplitude acoustic energy combined with cavitation nuclei can result in bioeffects. However, little is known about the bioeffects potential of acoustic parameters involved in radiation force and microbubble destruction pulse sequences applied at higher frequencies. In this pilot study, rat kidneys are exposed to high-duty cycle, low-amplitude pulse sequences known to cause substantial bubble translation due to radiation force, as well as high-amplitude short pulse sequences known to cause microbubble destruction. Both studies are performed at 7 MHz on a clinical ultrasound system, and implemented in three-dimensions (3-D) for entire kidney exposure. Analysis of biomarkers of renal injury and renal histopathology indicate that there was no significant renal damage due to these ultrasound parameters in conjunction with microbubbles within the study group.
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Affiliation(s)
- Kennita Johnson
- Joint Department of Biomedical Engineering, University of North Carolina-North Carolina State University, Chapel Hill, NC 27599, USA
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Histological observation of islet hemorrhage induced by diagnostic ultrasound with contrast agent in rat pancreas. PLoS One 2011; 6:e21617. [PMID: 21738734 PMCID: PMC3125214 DOI: 10.1371/journal.pone.0021617] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 06/03/2011] [Indexed: 01/02/2023] Open
Abstract
Contrast enhanced diagnostic ultrasound CEDUS has been shown to induce capillary hemorrhage in heart and kidney. This study characterized the capillary hemorrhage induced in rat pancreas. The pancreata of anesthetized hairless rats were accessed by laparotomy. A 1.5 MHz diagnostic ultrasound probe with 2.3 MPa peak rarefactional pressure amplitude and 1 s intermittent trigger was used to scan the pancreas, located at the focus (3.8 cm), through saline coupling. The probe was swept to expose the entire organ in 5 min during infusion of Definity® contrast agent at 10 µL/kg/min, and this was repeated in a reverse sweep. The entire pancreas was removed, spread flat for fixation and histological slides were prepared from the mid-plane. Slides were scored blind for islet hemorrhage over the entire area of the organ. Intra-islet microlesions were evident and hemorrhage surrounded many islets. The hemorrhage often impacted nearby acini, and expanded into inter-lobular septa. In CEDUS pancreata removed soon after scanning, 76.2±11.8% (n = 6) of islets had evidence of hemorrhage and/or islet microlesions compared to 1.1±2.5% (n = 5) for sham CEDUS (P<0.001). In pancreata removed after 4 hr, fibrin formation was detected by immunohistology in the hemorrhage and intra-islet microlesions. Diagnostic ultrasound with contrast agent induced substantial capillary hemorrhage in rat pancreas, concentrated particularly in the islets.
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Miller DL, Dou C, Lucchesi BR. Are ECG premature complexes induced by ultrasonic cavitation electrophysiological responses to irreversible cardiomyocyte injury? ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:312-20. [PMID: 21257092 PMCID: PMC3046393 DOI: 10.1016/j.ultrasmedbio.2010.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 11/10/2010] [Accepted: 11/23/2010] [Indexed: 05/03/2023]
Abstract
The objective of this study was to explore the relationship between premature complexes (PCs) in the electrocardiogram (ECG) and lethal injury of cardiomyocytes induced by ultrasound exposure of the heart with contrast-agent gas bodies in the circulation. Anesthetized rats were exposed in a heated water bath to 1.55 MHz focused ultrasound with bursts triggered at end systole during contrast agent infusion. PCs were detected in ECG recordings and cardiomyocyte necrosis was scored by identifying Evans blue-stained cells in multiple frozen sections. With 0.1 μL/kg/min infusion of contrast agent for 5 min, both effects increased strongly for 2-ms bursts with increasing peak rarefactional pressure amplitude >1 MPa. At 8 MPa, statistically significant effects were found even for no agent infusion relative to sham tests. For 2-ms bursts at 2 MPa, the highly significant bioeffects seen for 10-, 1- and 0.1-μL/kg/min infusion became marginally significant for 0.01 μL/kg/min, which indicated a lower probability of cavitation nucleation. Burst duration variation from 0.2-20 ms produced no substantial trends in the results. Overall, the two effects were well correlated (r(2) = 0.88). The PCs occurring during contrast-enhanced ultrasound therefore appear to be electrophysiological responses to irreversible cardiomyocyte injury induced by ultrasonic cavitation.
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Affiliation(s)
- Douglas L Miller
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109-5667, USA.
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Miller DL, Dou C, Wiggins RC. Contrast-enhanced diagnostic ultrasound causes renal tissue damage in a porcine model. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2010; 29:1391-401. [PMID: 20876892 PMCID: PMC2948414 DOI: 10.7863/jum.2010.29.10.1391] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
OBJECTIVE Glomerular capillary hemorrhage (GCH) has been reported and confirmed as a consequence of contrast-enhanced diagnostic ultrasound (CEDUS) imaging of rat kidney. This study assessed renal tissue injury in the larger porcine model. METHODS The right kidneys of anesthetized pigs were imaged in 8 groups of 4 pigs. A Vingmed System Five ultrasound machine (General Electric Co, Cincinnati, OH) was used at 1.5 MHz in the B-mode to intermittently scan the kidney at 4-second intervals. An Acuson Sequoia 512 machine (Siemens Medical Solutions, Mountain View, CA) was used in the 1.5-MHz Cadence contrast pulse sequencing mode with intermittent agent clearance bursts at 4-second intervals. Kidneys were scanned transabdominally or after laparotomy through a saline standoff. The second machine's probe was placed in contact with the kidney for 1 group. A perflutren lipid microsphere contrast agent (Definity; Lantheus Medical Imaging, Inc, North Billerica, MA) was infused at 4 μL/kg/min (diluted 33:1 in saline) for 4 minutes during scanning. RESULTS Blood-filled urinary tubules were evident on the kidney surface for all groups except the group with the probe in contact with the kidney. Glomerular capillary hemorrhage was found by histologic processing in 31.7% ± 9.8% (mean ± SD) of glomeruli in the center of the scan plane for 1.7-MPa transabdominal scanning and 1.5% ± 2.9% of glomeruli in sham samples (P < .05). In addition, hematuria was detected after scanning, and tubular obstruction occurred in some nephrons. CONCLUSIONS Renal tissue damage was induced by CEDUS in the porcine model. This result, together with previous studies in rats, support a hypothesis that GCH would occur in humans from similar CEDUS exposure.
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Affiliation(s)
- Douglas L Miller
- Department of Radiology, University of Michigan Medical Center, Ann Arbor, MI 48109-0553, USA.
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