126
|
Miller DL. Induction of pulmonary hemorrhage in rats during diagnostic ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:1476-1482. [PMID: 22698500 DOI: 10.1016/j.ultrasmedbio.2012.04.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 03/26/2012] [Accepted: 04/06/2012] [Indexed: 06/01/2023]
Abstract
The induction of pulmonary hemorrhage by pulsed ultrasound was discovered over 20 years ago. This phenomenon may pose a risk of patient lung injury, particularly for point of care pulmonary ultrasound. A diagnostic ultrasound machine (HDI 5000; Philips Healthcare, Andover MA USA) with 7.6 MHz (CL15-7) linear array was used to image the right lung of anesthetized rats in a warmed water bath. The image showed rapid initiation and progression of comet tail artifacts across the lung image for an on-screen mechanical index (MI) of 0.9, which corresponded to a pulmonary hemorrhage in the lung. Groups of rats were scanned at a range of MI settings and a threshold was located at an MI of about 0.44. This finding indicated a greater sensitivity to pulmonary ultrasound than was expected, based on previous results. Further research is needed to understand this phenomenon and to develop safety guidelines for sonographers.
Collapse
|
127
|
Rodriguez G, Quan D. Bacterial growth on ED ultrasound machines. Am J Emerg Med 2011; 29:816-7. [PMID: 21676573 DOI: 10.1016/j.ajem.2011.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 03/08/2011] [Accepted: 03/15/2011] [Indexed: 01/22/2023] Open
|
128
|
Buys SS, Partridge E, Black A, Johnson CC, Lamerato L, Isaacs C, Reding DJ, Greenlee RT, Yokochi LA, Kessel B, Crawford ED, Church TR, Andriole GL, Weissfeld JL, Fouad MN, Chia D, O'Brien B, Ragard LR, Clapp JD, Rathmell JM, Riley TL, Hartge P, Pinsky PF, Zhu CS, Izmirlian G, Kramer BS, Miller AB, Xu JL, Prorok PC, Gohagan JK, Berg CD. Effect of screening on ovarian cancer mortality: the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Randomized Controlled Trial. JAMA 2011; 305:2295-303. [PMID: 21642681 DOI: 10.1001/jama.2011.766] [Citation(s) in RCA: 852] [Impact Index Per Article: 65.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CONTEXT Screening for ovarian cancer with cancer antigen 125 (CA-125) and transvaginal ultrasound has an unknown effect on mortality. OBJECTIVE To evaluate the effect of screening for ovarian cancer on mortality in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. DESIGN, SETTING, AND PARTICIPANTS Randomized controlled trial of 78,216 women aged 55 to 74 years assigned to undergo either annual screening (n = 39,105) or usual care (n = 39,111) at 10 screening centers across the United States between November 1993 and July 2001. Intervention The intervention group was offered annual screening with CA-125 for 6 years and transvaginal ultrasound for 4 years. Participants and their health care practitioners received the screening test results and managed evaluation of abnormal results. The usual care group was not offered annual screening with CA-125 for 6 years or transvaginal ultrasound but received their usual medical care. Participants were followed up for a maximum of 13 years (median [range], 12.4 years [10.9-13.0 years]) for cancer diagnoses and death until February 28, 2010. MAIN OUTCOME MEASURES Mortality from ovarian cancer, including primary peritoneal and fallopian tube cancers. Secondary outcomes included ovarian cancer incidence and complications associated with screening examinations and diagnostic procedures. RESULTS Ovarian cancer was diagnosed in 212 women (5.7 per 10,000 person-years) in the intervention group and 176 (4.7 per 10,000 person-years) in the usual care group (rate ratio [RR], 1.21; 95% confidence interval [CI], 0.99-1.48). There were 118 deaths caused by ovarian cancer (3.1 per 10,000 person-years) in the intervention group and 100 deaths (2.6 per 10,000 person-years) in the usual care group (mortality RR, 1.18; 95% CI, 0.82-1.71). Of 3285 women with false-positive results, 1080 underwent surgical follow-up; of whom, 163 women experienced at least 1 serious complication (15%). There were 2924 deaths due to other causes (excluding ovarian, colorectal, and lung cancer) (76.6 per 10,000 person-years) in the intervention group and 2914 deaths (76.2 per 10,000 person-years) in the usual care group (RR, 1.01; 95% CI, 0.96-1.06). CONCLUSIONS Among women in the general US population, simultaneous screening with CA-125 and transvaginal ultrasound compared with usual care did not reduce ovarian cancer mortality. Diagnostic evaluation following a false-positive screening test result was associated with complications. Trial Registration clinicaltrials.gov Identifier: NCT00002540.
Collapse
|
129
|
Bigelow TA, Church CC, Sandstrom K, Abbott JG, Ziskin MC, Edmonds PD, Herman B, Thomenius KE, Teo TJ. The thermal index: its strengths, weaknesses, and proposed improvements. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2011; 30:714-734. [PMID: 21527623 DOI: 10.7863/jum.2011.30.5.714] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The thermal index (TI) has been used as a relative indicator of thermal risk during diagnostic ultrasound examinations for many years. It is useful in providing feedback to the clinician or sonographer, allowing assessment of relative, potential risks to the patient of an adverse effect due to a thermal mechanism. Recently, several shortcomings of the TI formulations in quantifying the risk to the patient have been identified by members of the basic scientific community, and possible improvements to address these shortcomings have been proposed. For this reason, the Output Standards Subcommittee of the American Institute of Ultrasound in Medicine convened a subcommittee to review the strengths of the TI formulations as well as their weaknesses and proposed improvements. This article summarizes the findings of this subcommittee. After a careful review of the literature and an assessment of the cost of updating the TI formulations while maximizing the quality of patient care, the Output Standards Subcommittee makes the following recommendations: (1) some inconsistencies in the current TI formulations should be resolved, and the break point distance should be redefined to take focusing into consideration; (2) an entirely new indicator of thermal risk that incorporates the time dependence not be implemented at this time but be included in continuing efforts toward standards or consensus documents; (3) the exponential dependence of risk on temperature not be incorporated into a new definition of the TI formulations at this time but be included in continuing efforts toward standards or consensus documents; (4) the TI formulations not be altered to include nonlinear propagation at this time but be included in continuing efforts toward standards or consensus documents; and (5) a new indicator for risk from thermal mechanisms should be developed, distinct from the traditional TI formulations, for new imaging modalities such as acoustic radiation force impulse imaging, which have more complicated pulsing sequences than traditional imaging.
Collapse
|
130
|
Routine screening of the carotid arteries not recommended. HARVARD HEALTH LETTER 2011; 36:7. [PMID: 21560283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
|
131
|
Franchi-Abella S. [Ultrasound: a marvellous tool for fetal and neonatal study, but is there any specific precaution to take?]. ACTA ACUST UNITED AC 2011; 92:109-10. [PMID: 21352741 DOI: 10.1016/j.jradio.2010.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 12/02/2010] [Indexed: 11/20/2022]
|
132
|
Rajaraman P, Simpson J, Neta G, Berrington de Gonzalez A, Ansell P, Linet MS, Ron E, Roman E. Early life exposure to diagnostic radiation and ultrasound scans and risk of childhood cancer: case-control study. BMJ 2011; 342:d472. [PMID: 21310791 PMCID: PMC3037470 DOI: 10.1136/bmj.d472] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE To examine childhood cancer risks associated with exposure to diagnostic radiation and ultrasound scans in utero and in early infancy (age 0-100 days). DESIGN Case-control study. SETTING England and Wales. PARTICIPANTS 2690 childhood cancer cases and 4858 age, sex, and region matched controls from the United Kingdom Childhood Cancer Study (UKCCS), born 1976-96. MAIN OUTCOME MEASURES Risk of all childhood cancer, leukaemia, lymphoma, and central nervous system tumours, measured by odds ratios. RESULTS Logistic regression models conditioned on matching factors, with adjustment for maternal age and child's birth weight, showed no evidence of increased risk of childhood cancer with in utero exposure to ultrasound scans. Some indication existed of a slight increase in risk after in utero exposure to x rays for all cancers (odds ratio 1.l4, 95% confidence interval 0.90 to 1.45) and leukaemia (1.36, 0.91 to 2.02), but this was not statistically significant. Exposure to diagnostic x rays in early infancy (0-100 days) was associated with small, non-significant excess risks for all cancers and leukaemia, as well as increased risk of lymphoma (odds ratio 5.14, 1.27 to 20.78) on the basis of small numbers. CONCLUSIONS Although the results for lymphoma need to be replicated, all of the findings indicate possible risks of cancer from radiation at doses lower than those associated with commonly used procedures such as computed tomography scans, suggesting the need for cautious use of diagnostic radiation imaging procedures to the abdomen/pelvis of the mother during pregnancy and in children at very young ages.
Collapse
|
133
|
ter Haar G, Shaw A, Pye S, Ward B, Bottomley F, Nolan R, Coady AM. Guidance on reporting ultrasound exposure conditions for bio-effects studies. ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:177-83. [PMID: 21257086 DOI: 10.1016/j.ultrasmedbio.2010.10.021] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2009] [Revised: 10/16/2010] [Accepted: 10/19/2010] [Indexed: 05/07/2023]
Abstract
This guidance is intended to encourage best practice among researchers into ultrasound bio-effects in terms of how they determine and report the exposure conditions used in their studies. It covers both diagnostic and therapeutic applications of ultrasound and is intended to be useful to the researchers themselves, to the review boards of ethical and funding committees and to the editors and reviewers of scientific journals. Recommendations are made for reporting formats, depending on the information available, and level of the study.
Collapse
|
134
|
Ziskin MC. The thermal dose index. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2010; 29:1475-1479. [PMID: 20876902 DOI: 10.7863/jum.2010.29.10.1475] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
OBJECTIVE A new index is proposed to help sonographers easily assess the risk of an adverse thermal effect arising from a clinical examination. It is called the thermal dose index (TDI). METHODS The TDI uses the familiar thermal index (TI) and the examination duration to compute a dimensionless index. RESULTS The greater the TDI value, the greater the risk of a thermally induced adverse effect. If the TDI is 1 or less, there is no expectation of a thermally induced adverse effect. CONCLUSIONS Like the TI, the TDI would be a convenient index that is continually updated and displayed during an ultrasound examination. The TDI is a new estimate of thermal risk that takes into account the duration of an ultrasound examination.
Collapse
|
135
|
Ecke TH, Gerullis H, Heuck CJ, Bartel P, Hallmann S, Koch S, Ruttloff J. Does a new ultrasound probe change the complication rates of transrectal ultrasound-guided needle biopsies of the prostate? Anticancer Res 2010; 30:3071-3076. [PMID: 20683057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
BACKGROUND Transrectal ultrasound-guided prostate needle biopsies are performed to diagnose prostate cancer. This study prospectively evaluated the safety, morbidity and complication rates with two different ultrasound probes. PATIENTS AND METHODS Three huntred and thirty-two patients were biopsied using a biplane 7.5 MHz probe (GE Medical Systems Kretz Ultrasound, Zipf, Austria) and 101 patients using a biplane 5-10 MHz probe (BK-Medical, Herlev, Denmark). Four weeks after the procedure the patients were asked to fill out a questionnaire. RESULTS There were 3 major and 75 minor complications. The most common complication was haematuria in 8.1% of cases, followed by pain with urination in 5.3% of cases. After changing the ultrasound probe, the complication rates were slightly higher, but no statistical difference in any of the complication rates was found between the two groups. CONCLUSIONS Changing the method within the same team has no influence on complication rates and on prostate cancer detection rates.
Collapse
|
136
|
Hua L, Doll T. A series of 3 cases of corneal abrasion with multiple etiologies. ACTA ACUST UNITED AC 2010; 81:83-5. [PMID: 20152781 DOI: 10.1016/j.optm.2009.05.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 04/30/2009] [Accepted: 05/23/2009] [Indexed: 11/19/2022]
Abstract
BACKGROUND Most corneal abrasions are caused by mechanical injuries affecting the superficial epithelial layer. Although one of the functions of the eyelid is to protect the eye, its reaction time of about 425 msec is slower than many ocular insults; thus, corneal abrasions are among the most commonly occurring eye emergencies. CASE REPORTS Three cases of corneal abrasions with different etiologies are presented. The first case was a large abrasion of the cornea near the visual axis caused by a wood chip. A metal foreign body with rust was lodged in the cornea from metal grinding in the second case. The third case was iatrongenically induced by an A-scan probe while a fellow student was measuring the axial length of the eye. CONCLUSION Corneal abrasions are one of the most common ocular conditions presented to eye clinics or emergency departments. Although there are different etiologies of abraded corneal epithelium, current clinical management for most corneal abrasions involves a bandage contact lens, use of topical antibiotics, and cycloplegics. Large and central corneal abrasions, however, warrant a consultation with a corneal specialist.
Collapse
|
137
|
Tran TA, Le Guennec JY, Babuty D, Bougnoux P, Tranquart F, Bouakaz A. On the mechanisms of ultrasound contrast agents-induced arrhythmias. ULTRASOUND IN MEDICINE & BIOLOGY 2009; 35:1050-1056. [PMID: 19195768 DOI: 10.1016/j.ultrasmedbio.2008.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 11/02/2008] [Accepted: 11/20/2008] [Indexed: 05/27/2023]
Abstract
Recent reports have shown that imaging hard-shelled ultrasound (US) contrast agents at high mechanical indices engenders premature ventricular contractions (PVCs). We have shown that the oscillations of microbubbles next to a cell induce a mechanical pressure on its membrane resulting in the activation of stretch activated channels (SAC). The aim of this study is to demonstrate, in vivo and in vitro, the relationship between PVCs and SAC opening. Five anesthetized rats were used. PVCs were created in vivo with (1) US and a diluted solution of contrast microbubbles injected intravenously through the tail vein at a rate of 0.5 mL per min and (2) a manually induced mechanical stimulus, which consisted of stimulations by a flexible catheter introduced into the rat aorta and pushed until the left ventricle. PVCs were quantified through ECG measurements. In vitro experiments consisted of patch Clamp measurements on HL-1 heart cell line. The stimulation was carried out either manually with a glass rod or with US and microbubbles. For both in vivo and in vitro experiments, US consisted of 40-cycle waveforms at 1 MHz and peak negative pressures up to 300 kPa and exposure time varied from 1 to 2 min. We should emphasize that these parameters are different from those used in diagnostic conditions. In vivo, microbubbles and US at 300 kPa induced modification of rat's ECG while pressures below 300 kPa did not induce any PVC. US alone did not modify the rat's ECG. Similar PVCs were also created when stimulation with a catheter was applied. Regular heart beat rate was recovered immediately after the stimulation was stopped. In vitro, the mechanical stretch induced a cell membrane depolarization due to SAC opening. Similar effect was observed with US and microbubbles. The cell potential returned to its initial value when the stimulation was released. In conclusion, we presume that PVCs are generated through a cascade of events characterized by a mechanical action of oscillating microbubbles, opening of stretch activated ion channels, membrane depolarization and triggering of action potentials.
Collapse
|
138
|
Karagoz I, Kartal MK. A new safety parameter for diagnostic ultrasound thermal bioeffects: safe use time. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2009; 125:3601-3610. [PMID: 19507942 DOI: 10.1121/1.3126525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
It is widely accepted that diagnostic ultrasound has the potential to elevate the temperature of tissue being scanned. Because both the maximum value of the temperature rise and the temporal profile of that rise are necessary to estimate the risk correctly, the temperature rise [DeltaT(t)] at an observation point for an exposure condition is presumed to have two components, that is, DeltaT(t)=DeltaT(max)X(t). The amplitude component DeltaT(max) is the maximum value of DeltaT(t), and the exposure time component X(t) represents the time dependency of that DeltaT(t). Ninety-six cases were investigated to obtain the proposed DeltaT(t) model at six frequencies, four source diameters, and four f-numbers. Then, using the relative change in the rate of induction of a thermal effect due to ultrasound exposure that produces DeltaT(t) different from a threshold exposure, the safe use time (SUT) model was constructed. SUT informs the user of the maximum duration of exposure in a region at a particular output level that would be no more hazardous than scanning at the threshold exposure. Using the SUT model, high power ultrasound can be applied for a short time so that the user can improve imaging performance while staying within safe limits.
Collapse
|
139
|
Nelson TR, Fowlkes JB, Abramowicz JS, Church CC. Ultrasound biosafety considerations for the practicing sonographer and sonologist. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2009; 28:139-50. [PMID: 19168764 DOI: 10.7863/jum.2009.28.2.139] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The purpose of this article is to present the practicing sonographer and sonologist with an overview of the biohazards of ultrasound and guidelines for safe use.
Collapse
|
140
|
Oelze ML, Miller RJ, Blue JP, Zachary JF, O'Brien WD. Estimation of the acoustic impedance of lung versus level of inflation for different species and ages of animals. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2008; 124:2340-52. [PMID: 19062872 PMCID: PMC2677343 DOI: 10.1121/1.2973186] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
In a previous study, it was hypothesized that ultrasound-induced lung damage was related to the transfer of ultrasonic energy into the lungs (W. D. O'Brien et al. 2002, "Ultrasound-induced lung hemorrhage: Role of acoustic boundary conditions at the pleural surface," J. Acoust. Soc. Am. 111, 1102-1109). From this study a technique was developed to: 1) estimate the impedance (Mrayl) of fresh, excised, ex vivo rat lung versus its level of inflation (cm H(2)O) and 2) predict the fraction of ultrasonic energy transmitted into the lung (M. Oelze et al. 2003, "Impedance measurements of ex vivo rat lung at different volumes of inflation." J. Acoust. Soc. Am. 114, 3384-3393). In the current study, the same technique was used to estimate the frequency-dependent impedance of lungs from rats, rabbits, and pigs of various ages. Impedance values were estimated from lungs under deflation (atmospheric pressure, 0 cm H(2)O) and three volumes of inflation pressure [7 cm H(2)O (5 cm H(2)O for pigs), 10 cm H(2)O, and 15 cm H(2)O]. Lungs were scanned in a tank of degassed 37 degrees C water. The frequency-dependent acoustic pressure reflection coefficient was determined over a frequency range of 3.5-10 MHz. From the reflection coefficient, the frequency-dependent lung impedance was calculated with values ranging from an average of 1.4 Mrayl in deflated lungs (atmospheric pressure) to 0.1 Mrayl for fully inflated lungs (15 cm H(2)O). Across all species, deflated lung (i.e., approximately 7% of the total lung capacity) had impedance values closer to tissue values, suggesting that more acoustic energy was transmitted into the lung under deflated conditions. Finally, the impedance values of deflated lungs from different species at different ages were compared with the thresholds for ultrasound-induced lung damage. The comparison revealed that increases in ultrasonic energy transmission corresponded to lower injury threshold values.
Collapse
|
141
|
Miao H, Gracewski SM, Dalecki D. Ultrasonic excitation of a bubble inside a deformable tube: implications for ultrasonically induced hemorrhage. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2008; 124:2374-84. [PMID: 19062875 PMCID: PMC2677346 DOI: 10.1121/1.2967488] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Various independent investigations indicate that the presence of microbubbles within blood vessels may increase the likelihood of ultrasound-induced hemorrhage. To explore potential damage mechanisms, an axisymmetric coupled finite element and boundary element code was developed and employed to simulate the response of an acoustically excited bubble centered within a deformable tube. As expected, the tube mitigates the expansion of the bubble. The maximum tube dilation and maximum hoop stress were found to occur well before the bubble reached its maximum radius. Therefore, it is not likely that the expanding low pressure bubble pushes the tube wall outward. Instead, simulation results indicate that the tensile portion of the acoustic excitation plays a major role in tube dilation and thus tube rupture. The effects of tube dimensions (tube wall thickness 1-5 microm), material properties (Young's modulus 1-10 MPa), ultrasound frequency (1-10 MHz), and pressure amplitude (0.2-1.0 MPa) on bubble response and tube dilation were investigated. As the tube thickness, tube radius, and acoustic frequency decreased, the maximum hoop stress increased, indicating a higher potential for tube rupture and hemorrhage.
Collapse
|
142
|
ter Haar G. Bubble trouble? ULTRASCHALL IN DER MEDIZIN (STUTTGART, GERMANY : 1980) 2008; 29:550-551. [PMID: 18937172 DOI: 10.1055/s-0028-1098033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
|
143
|
Miller DL, Dou C, Wiggins RC. Frequency dependence of kidney injury induced by contrast-aided diagnostic ultrasound in rats. ULTRASOUND IN MEDICINE & BIOLOGY 2008; 34:1678-87. [PMID: 18485567 PMCID: PMC2586119 DOI: 10.1016/j.ultrasmedbio.2008.03.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 02/22/2008] [Accepted: 03/03/2008] [Indexed: 05/04/2023]
Abstract
This study was performed to examine the frequency dependence of glomerular capillary hemorrhage (GCH) induced by contrast-aided diagnostic ultrasound (DUS) in rats. Diagnostic ultrasound scanners were used for exposure at 3.2, 5.0 and 7.4 MHz, and previously published data at 1.5 and 2.5 MHz was also included. A laboratory exposure system was used to simulate DUS exposure at 1.0, 1.5, 2.25, 3.5, 5.0 and 7.5 MHz, with higher peak rarefactional pressure amplitudes (PRPAs) than were available from our DUS systems. The right kidneys of rats mounted in a water bath were exposed to intermittent image pulse sequences at 1 s intervals during infusion of diluted ultrasound contrast agent. The percentage of GCH was zero for low PRPAs, and then rapidly increased with increasing PRPAs above an apparent threshold, p(t). The values of p(t) were approximately proportional to the ultrasound frequency, f, such that p(t) /f was approximately 0.5 MPa/MHz for DUS and 0.6 MPa/MHz for laboratory system exposures. The increasing thresholds with increasing frequency limited the GCH effect for contrast-aided DUS, and no GCH was seen for DUS at 5.0 or 7.4 MHz for the highest available PRPAs.
Collapse
|
144
|
Valentino B, Caruso G, Lipari EF, Lipari D, Campisi A, Salvaggio G, Lagalla R. Anatomical and clinical study on effects of sonography with pulse inversion and microbubble contrast in rabbit kidney. ITALIAN JOURNAL OF ANATOMY AND EMBRYOLOGY = ARCHIVIO ITALIANO DI ANATOMIA ED EMBRIOLOGIA 2008; 113:159-166. [PMID: 19205588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Aim of the present study was to evaluate by transmission electron microscope (TEM) modifications in rabbit kidney-parenchyma after submission to ultrasound contrast agent (UCA) with Pulse Inversion Harmonic Imaging (PIHI). Seven inbred male albino rabbits were divided into three groups: 1) control group (n = 1 animal); 2) sonicated group (n = 3 animals); 3) sonicated group with UCA injection (CEUS) (n = 3 animals). The first group was not exposed to ultrasonography (US) and/or UCA. The second and third groups underwent baseline US and later to US with PIHI with a high mechanical index; in the third group UCA was simultaneously administered. Ultrastructural studies and image analysis were blindly performed on 50 samples (2mm3), including cortex and medulla, by two experienced pathologists with TEM. By TEM observations of the first and second groups showed no structural modifications of renal cortex and medulla. TEM observations of the third group showed ultrastructural changes of renal corpuscle, proximal and distal convoluted tubules and collecting tubules; further in the most of observed sections the filtration membrane had an alteration of typical trilaminar pattern and vacuolisation of glomerular endothelial cells with irregular edges. Therefore in rabbit kidney submitted to CEUS some ultrastructural modifications were observed.
Collapse
|
145
|
Fowlkes JB. American Institute of Ultrasound in Medicine consensus report on potential bioeffects of diagnostic ultrasound: executive summary. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2008; 27:503-515. [PMID: 18359906 DOI: 10.7863/jum.2008.27.4.503] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The continued examination of potential biological effects of ultrasound and their relationship to clinical practice is a key element in evaluating the safety of diagnostic ultrasound. Periodically, the American Institute of Ultrasound in Medicine (AIUM) sponsors conferences bringing experts together to examine the literature on ultrasound bioeffects and to develop conclusions and recommendations related to diagnostic ultrasound. The most recent effort included the examination of effects whose origins were thermal or nonthermal, with separate evaluations for potential effects related to fetal ultrasound. In addition, potential effects due to the introduction of ultrasound contrast agents were summarized. This information can be used to assess risks in comparison to the benefits of diagnostic ultrasound. The conclusions and recommendations are organized into 5 broad categories, with a comprehensive background and evaluation of each topic provided in the corresponding articles in this issue. The following summary is not meant as a substitute for the detailed examination of issues presented in each of the articles but rather as a means to facilitate further study of this consensus report and implementation of its recommendations. The conclusions and recommendations are the result of several rounds of deliberations at the consensus conference, subsequent review by the Bioeffects Committee of the AIUM, and approval by the AIUM Board of Governors.
Collapse
|
146
|
Church CC, Carstensen EL, Nyborg WL, Carson PL, Frizzell LA, Bailey MR. The risk of exposure to diagnostic ultrasound in postnatal subjects: nonthermal mechanisms. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2008; 27:565-596. [PMID: 18359909 DOI: 10.7863/jum.2008.27.4.565] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This review examines the nonthermal physical mechanisms by which ultrasound can harm tissue in postnatal patients. First the physical nature of the more significant interactions between ultrasound and tissue is described, followed by an examination of the existing literature with particular emphasis on the pressure thresholds for potential adverse effects. The interaction of ultrasonic fields with tissue depends in a fundamental way on whether the tissue naturally contains undissolved gas under normal physiologic conditions. Examples of gas-containing tissues are lung and intestine. Considerable effort has been devoted to investigating the acoustic parameters relevant to the threshold and extent of lung hemorrhage. Thresholds as low as 0.4 MPa at 1 MHz have been reported. The situation for intestinal damage is similar, although the threshold appears to be somewhat higher. For other tissues, auditory stimulation or tactile perception may occur, if rarely, during exposure to diagnostic ultrasound; ultrasound at similar or lower intensities is used therapeutically to accelerate the healing of bone fractures. At the exposure levels used in diagnostic ultrasound, there is no consistent evidence for adverse effects in tissues that are not known to contain stabilized gas bodies. Although modest tissue damage may occur in certain identifiable applications, the risk for induction of an adverse biological effect by a nonthermal mechanism due to exposure to diagnostic ultrasound is extremely small.
Collapse
|
147
|
O'Brien WD, Deng CX, Harris GR, Herman BA, Merritt CR, Sanghvi N, Zachary JF. The risk of exposure to diagnostic ultrasound in postnatal subjects: thermal effects. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2008; 27:517-35; quiz 537-40. [PMID: 18359907 PMCID: PMC2724319 DOI: 10.7863/jum.2008.27.4.517] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This review evaluates the thermal mechanism for ultrasound-induced biological effects in postnatal subjects. The focus is the evaluation of damage versus temperature increase. A view of ultrasound-induced temperature increase is presented, based on thermodynamic Arrhenius analyses. The hyperthermia and other literature revealed data that allowed for an estimate of a temperature increase threshold of tissue damage for very short exposure times. This evaluation yielded an exposure time extension of the 1997 American Institute of Ultrasound in Medicine Conclusions Regarding Heat statement (American Institute of Ultrasound in Medicine, Laurel, MD) to 0.1 second for nonfetal tissue, where, at this exposure time, the temperature increase threshold of tissue damage was estimated to be about 18 degrees C. The output display standard was also evaluated for soft tissue and bone cases, and it was concluded that the current thermal indices could be improved to reduce the deviations and scatter of computed maximum temperature rises.
Collapse
|
148
|
Murat FJ, Poissonnier L, Pasticier G, Gelet A. High-intensity focused ultrasound (HIFU) for prostate cancer. Cancer Control 2007; 14:244-9. [PMID: 17615530 DOI: 10.1177/107327480701400307] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The growing interest in high-intensity focused ultrasound (HIFU) is mainly due to its potential applications as a minimally invasive therapy. HIFU has been assessed for its role in the treatment of localized prostate cancer in patients who otherwise would not have benefited from surgery and in local recurrences after radiation failure. METHODS Relevant information on HIFU treatment was identified through a MEDLINE search using specified terms. Papers that presented original outcomes were included in the present review. RESULTS High biochemical efficacy, excellent tumor local control and favorable mid-term oncological data with a low morbidity rate have been proven in many series of patients. CONCLUSIONS Although HIFU is a recent and emerging technology, it has been well studied and developed to a point that HIFU will undoubtedly be an effective alternative to radiation therapy.
Collapse
|
149
|
Miller DL, Dou C, Wiggins RC. Simulation of diagnostic ultrasound image pulse sequences in cavitation bioeffects research. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2007; 122:2002-8. [PMID: 17902837 DOI: 10.1121/1.2773991] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Research on cavitational bioeffects of diagnostic ultrasound (DUS) typically involves a diagnostic scanner as the exposure source. However, this can limit the ranges of exposure parameters for experimentation. Anesthetized hairless rats were mounted in a water bath and their right kidneys were exposed to ultrasound. Amplitude modulation with Gaussian envelopes simulated the image pulse sequences (IPSs) produced by diagnostic scanning. A 10 mulkgmin IV dose of Definity((R)) contrast agent was given during 1-5 min exposures. Glomerular capillary hemorrhage was assessed by histology. A stationary exposure approximated the bioeffects induced by DUS within the beam area. However, the use of five closely spaced exposures more faithfully reproduced the total effect produced within a DUS scan plane. Single pulses delivered at 1 s intervals induced the same effect as the simulated DUS. Use of 100 ms triangle-wave modulations for ramp-up or ramp-down of the IPS gave no effect or a large effect, respectively. Finally, an air-backed transducer simulating DUS without contrast agent showed a zero effect even operating at twice the present DUS guideline upper limit. Relatively simple single-element laboratory exposure systems can simulate diagnostic ultrasound exposure and allow exploration of parameter ranges beyond those available on present clinical systems.
Collapse
|
150
|
Church CC. A proposal to clarify the relationship between the thermal index and the corresponding risk to the patient. ULTRASOUND IN MEDICINE & BIOLOGY 2007; 33:1489-94. [PMID: 17512108 DOI: 10.1016/j.ultrasmedbio.2007.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 02/28/2007] [Accepted: 03/02/2007] [Indexed: 05/15/2023]
Abstract
The thermal index (TI) displayed on the screens of most modern diagnostic ultrasound machines is linearly proportional to the absorbed power or, equivalently, to the in-situ intensity or temperature rise. Users are instructed to interpret the TI as a "relative indication of bioeffect risk." The thermal dose is a well-known empirical relationship between the temperature T of a biological system and the time t needed for that temperature to induce a deleterious effect. For any two temperatures, T1 and T2, and the corresponding times t1 and t2, required to produce the same level of effect, this general relation holds: t1/t2=RT2-T1, where R is the thermal normalization constant. Hence, it is experimentally determined that the rate of induction, or risk, of a thermal effect increases exponentially with temperature. Because exponential relationships are not intuitive to many users, there is a significant potential for underestimation of the thermal risk associated with exposure to diagnostic ultrasound. To better quantify this risk and thereby make the displayed information more useful, the current linear display of the calculated value of the thermal index, i.e., of TIcur, should be altered to an exponential form based on the thermal dose and representing the excess risk associated with the exposure: TInew=(RTIcur-1)/(R-1). This expression has the advantage that for the usual choice of R=4 for T<or=43 degrees C, TInew approximately TIcur in the range most often seen onscreen, i.e., TIcur<1.2, minimizing any confusion during a transition from TIcur to TInew. For the relatively rare but potentially much more serious circumstances when TIcur>3.5, the displayed TInew>>TIcur, consistent with empirical observations of the likelihood of harm. Additional advantages also obtain.
Collapse
|