1
|
Efectos biológicos adversos y seguridad del ultrasonido en el embarazo. Revisión sistemática. PERINATOLOGÍA Y REPRODUCCIÓN HUMANA 2018. [DOI: 10.1016/j.rprh.2018.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
2
|
Schneider ME, Lombardo P. Brain Surface Heating After Exposure to Ultrasound: An Analysis Using Thermography. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:1138-1144. [PMID: 26924696 DOI: 10.1016/j.ultrasmedbio.2016.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 11/05/2015] [Accepted: 01/05/2016] [Indexed: 06/05/2023]
Abstract
Ultrasound is the imaging modality of choice to monitor brain pathologies in neonates after complicated deliveries. Animal studies have indicated that ultrasound may cause heating of brain tissues. To date, no study has explored brain surface heating by ultrasound during clinically relevant exposure. Hence, we investigated heating effects of B-mode and pulsed Doppler (PD) mode on ex vivo lamb brains using thermography. Five brains were scanned for 5 min in B-mode or for 3 min, 1 min, 30 s or 15 s in PD mode. Brain surface temperature was measured pre- and post-exposure using thermography. The highest mean temperature increase was recorded by B-mode (3.82 ± 0.43°C). All five PD exposure protocols were associated with surface temperature increases of 2.1-2.7°C. These outcomes highlight for the first time that B-mode ultrasound can contribute to brain surface heating during a routine cranial scan. Scan duration should be minimised whenever possible.
Collapse
Affiliation(s)
- Michal E Schneider
- Department of Medical Imaging and Radiation Sciences, School of Biomedical Science, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia.
| | - Paul Lombardo
- Department of Medical Imaging and Radiation Sciences, School of Biomedical Science, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
3
|
Schneider‐Kolsky ME, Ayobi Z, Lombardo P, Brown D, Kedang B, Gibbs ME. Ultrasound exposure of the foetal chick brain: effects on learning and memory. Int J Dev Neurosci 2009; 27:677-83. [DOI: 10.1016/j.ijdevneu.2009.07.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 07/14/2009] [Accepted: 07/29/2009] [Indexed: 11/15/2022] Open
Affiliation(s)
- Michal E. Schneider‐Kolsky
- Department of Medical Imaging & Radiation SciencesSchool of Biomedical ScienceFaculty of Medicine, Nursing and Health SciencesMonash UniversityClayton3800VictoriaAustralia
| | - Zohel Ayobi
- Department of Anatomy & Developmental BiologySchool of Biomedical ScienceFaculty of Medicine, Nursing and Health SciencesMonash UniversityClayton3800VictoriaAustralia
| | - Paul Lombardo
- Department of Medical Imaging & Radiation SciencesSchool of Biomedical ScienceFaculty of Medicine, Nursing and Health SciencesMonash UniversityClayton3800VictoriaAustralia
| | - Damian Brown
- Department of Medical Imaging & Radiation SciencesSchool of Biomedical ScienceFaculty of Medicine, Nursing and Health SciencesMonash UniversityClayton3800VictoriaAustralia
| | - Ben Kedang
- Department of Medical Imaging & Radiation SciencesSchool of Biomedical ScienceFaculty of Medicine, Nursing and Health SciencesMonash UniversityClayton3800VictoriaAustralia
| | - Marie E. Gibbs
- Department of Anatomy & Developmental BiologySchool of Biomedical ScienceFaculty of Medicine, Nursing and Health SciencesMonash UniversityClayton3800VictoriaAustralia
| |
Collapse
|
4
|
Liang HD, Zhou LX, Wells PNT, Halliwell M. Temperature measurement by thermal strain imaging with diagnostic power ultrasound, with potential for thermal index determination. ULTRASOUND IN MEDICINE & BIOLOGY 2009; 35:773-780. [PMID: 19243879 DOI: 10.1016/j.ultrasmedbio.2008.10.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 10/19/2008] [Accepted: 10/31/2008] [Indexed: 05/27/2023]
Abstract
Over the years, there has been a substantial increase in acoustic exposure in diagnostic ultrasound as new imaging modalities with higher intensities and frame rates have been introduced; and more electronic components have been packed into the probe head, so that there is a tendency for it to become hotter. With respect to potential thermal effects, including those which may be hazardous occurring during ultrasound scanning, there is a correspondingly growing need for in vivo techniques to guide the operator as to the actual temperature rise occurring in the examined tissues. Therefore, an in vivo temperature estimator would be of considerable practical value. The commonly-used method of tissue thermal index (TI) measurement with a hydrophone in water could underestimate the actual value of TI (in one report by as much as 2.9 times). To obtain meaningful results, it is necessary to map the temperature elevation in 2-D (or 3-D) space. We present methodology, results and validation of a 2-D spatial and temporal thermal strain ultrasound temperature estimation technique in phantoms, and its apparently novel application in tracking the evolution of heat deposition at diagnostic exposure levels. The same ultrasound probe is used for both transmission and reception. The displacement and thermal strain estimation methods are similar to those used in high-intensity focused ultrasound thermal monitoring. The use of radiofrequency signals permits the application of cross correlation as a similarity measurement for tracking feature displacement. The displacement is used to calculate the thermal strain directly related to the temperature rise. Good agreement was observed between the temperature rise and the ultrasound power and scan duration. Thermal strain up to 1.4% was observed during 4000-s scan. Based on the results obtained for the temperature range studied in this work, the technique demonstrates potential for applicability in phantom (and possibly in vivo tissue) temperature measurement for the determination of TI.
Collapse
|
5
|
Abramowicz JS, Barnett SB, Duck FA, Edmonds PD, Hynynen KH, Ziskin MC. Fetal thermal effects of diagnostic ultrasound. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2008; 27:541-59; quiz 560-3. [PMID: 18359908 DOI: 10.7863/jum.2008.27.4.541] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Processes that can produce a biological effect with some degree of heating (ie, about 1 degrees C above the physiologic temperature) act via a thermal mechanism. Investigations with laboratory animals have documented that pulsed ultrasound can produce elevations of temperature and damage in biological tissues in vivo, particularly in the presence of bone (intracranial temperature elevation). Acoustic outputs used to induce these adverse bioeffects are within the diagnostic range, although exposure times are usually considerably longer than in clinical practice. Conditions present in early pregnancy, such as lack of perfusion, may favor bioeffects. Thermally induced teratogenesis has been shown in many animal studies, as well as several controlled human studies; however, human studies have not shown a causal relationship between diagnostic ultrasound exposure during pregnancy and adverse biological effects to the fetus. All human epidemiologic studies, however, were conducted with commercially available devices predating 1992, that is, with acoustic outputs not exceeding a spatial-peak temporal-average intensity of 94 mW/cm2. Current limits in the United States allow a spatial-peak temporal-average intensity of 720 mW/cm2 for fetal applications. The synergistic effect of a raised body temperature (febrile status) and ultrasound insonation has not been examined in depth. Available evidence, experimental or epidemiologic, is insufficient to conclude that there is a causal relationship between obstetric diagnostic ultrasound exposure and obvious adverse thermal effects to the fetus. However, very subtle effects cannot be ruled out and indicate a need for further research, although research in humans may be extremely difficult to realize.
Collapse
Affiliation(s)
- Jacques S Abramowicz
- Department of Obstetrics and Gynecology, Rush University Medical Center, 1635 W Congress Pkwy, Chicago, IL 60612 USA.
| | | | | | | | | | | |
Collapse
|
6
|
Cucevic V, Brown AS, Foster FS. Thermal assessment of 40-MHz pulsed Doppler ultrasound in human eye. ULTRASOUND IN MEDICINE & BIOLOGY 2005; 31:565-573. [PMID: 15831335 DOI: 10.1016/j.ultrasmedbio.2005.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Revised: 12/22/2004] [Accepted: 01/06/2005] [Indexed: 05/24/2023]
Abstract
Tissue exposure to diagnostic pulsed Doppler ultrasound (US) can cause significant temperature rises. Temperature rise induced by US biomicroscopy (UBM) system (VS40, VisualSonics, Toronto, ON, Canada) was measured in ex vivo human and rabbit eyes with a 26-gauge K-type needle thermocouple. The operating frequency was 40 MHz with a free field I(SPTA) of 2.6 mW/cm(2) (B-mode) and 11.9 W/cm(2) (Doppler). Peak negative pressures were 5.22 MPa (B-mode) and 7.32 MPa (Doppler), resulting in MIs of 0.83 (B-mode) and 1.05 (Doppler mode). In Doppler mode, mean temperature rises of 2.27 degrees C and 1.93 degrees C were measured for the human lens and ciliary body after a 3-min insonation, vs. 2.66 degrees C for the rabbit lens. Our results indicate that US-induced temperature rise decreases with decreasing number of cycles, decreasing pulse-repetition frequency (PRF) or increased transmit attenuation, and is consistent with simple models of heating. To limit risk of temperature rises of 1 degrees C in human ciliary body, use of the maximum settings of 16 cycles (0.400 micros pulse duration), 20-kHz PRF should include 3-dB transmit attenuation, and exposure time should be limited. For insonation of the lens, exposure settings no higher than nine cycles (0.225-micros pulse duration) and 10-kHz PRF should be employed and exposure time limited to minimize risk of temperature increases of 1 degree C.
Collapse
Affiliation(s)
- Viviene Cucevic
- Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
| | | | | |
Collapse
|
7
|
Duckett AS, Reid AD, Leamen L, Cucevic V, Foster FS. Thermal assessment of 40-MHz ultrasound at soft tissue-bone interfaces. ULTRASOUND IN MEDICINE & BIOLOGY 2004; 30:665-673. [PMID: 15183233 DOI: 10.1016/j.ultrasmedbio.2004.02.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2003] [Revised: 02/11/2004] [Accepted: 02/26/2004] [Indexed: 05/24/2023]
Abstract
Tissue exposure to diagnostic ultrasound (US) can cause significant temperature rises. However, little has been reported on thermal effects of high-frequency US, and guidelines for the use of US do not necessarily apply to higher frequencies. Temperature rise induced by US biomicroscopy (UBM) was measured in phantoms containing mouse skulls and in anesthetized mice and mice post mortem, with a 50-microm K-type thermocouple. The operating frequency was 40 MHz with a free field I(SPTA) of 2.6 mW/cm(2) (B-mode) and 11.9 W/cm(2) (Doppler). Peak negative pressures were 5.22 MPa (B mode) and 7.32 MPa (Doppler), resulting in a mechanical index (MI) of 0.83 (B-mode) and 1.05 (Doppler mode). In Doppler mode, mean temperature rises of 1.80 degrees C and 1.73 degrees C were measured for proximal and distal skull phantom surfaces after a 3-min insonation. In vivo, the proximal mouse skull surface showed a mean temperature rise of 2.1 degrees C, with no statistically significant differences post mortem. Our results indicate temperature rise from insonation of bone interfaces using similar exposure parameters should not cause adverse bioeffects.
Collapse
Affiliation(s)
- Allison S Duckett
- Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ONT, Canada.
| | | | | | | | | |
Collapse
|
8
|
Barnett SB. Intracranial temperature elevation from diagnostic ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2001; 27:883-888. [PMID: 11476919 DOI: 10.1016/s0301-5629(01)00367-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Tissues of the central nervous system are sensitive to damage by physical agents, such as heat and ultrasound. Exposure to pulsed spectral Doppler ultrasound can significantly heat biologic tissue because of the relatively high intensities used and the need to hold the beam stationary during examinations. This has significant implications for sensitive neural tissue such as that exposed during spectral Doppler flow studies of fetal cerebral vessels. Recent changes in the FDA regulation allow delivery of almost eight times higher intensity into the fetal brain by ultrasound devices that incorporate an approved real-time output display in their design. In this situation, ultrasound users are expected to assess the risk/benefit ratio based on their interpretation of equipment output displays (including the thermal index, TI) and an understanding of the significance of biologic effects. To assist in the assessment of potential thermally mediated bioeffects, a number of conclusions can be drawn from the published scientific literature: the amount of ultrasound-induced intracranial heating increases with gestational age and the development of fetal bone; pulsed spectral Doppler ultrasound can produce biologically significant heating in the fetal brain; the rate of heating near bone is rapid, with approximately 75% of the maximum heating occurring within 30 s; blood flow has minimal cooling effect on ultrasound-induced heating of the brain when insonated with narrow focused clinical beams; the threshold for irreversible damage in the developing embryo and fetal brain is exceeded when a temperature increase of 4 degrees C is maintained for 5 min; an ultrasound exposure that produces a temperature increase of up to 1.5 degrees C in 120 s does not elicit measurable electrophysiologic responses in fetal brain; for some exposure conditions, the thermal index (TI), as used in the FDA-approved output display standard, underestimates the extent of ultrasound-induced intracranial temperature increase.
Collapse
Affiliation(s)
- S B Barnett
- CSIRO Telecommunications and Industrial Physics, Sydney, Australia.
| |
Collapse
|
9
|
Horder MM, Barnett SB, Vella GJ, Edwards MJ, Wood AK. Ultrasound-induced temperature increase in guinea-pig fetal brain in utero: third-trimester gestation. ULTRASOUND IN MEDICINE & BIOLOGY 1998; 24:1501-1510. [PMID: 10385971 DOI: 10.1016/s0301-5629(98)00090-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Temperature increase was measured at various depths in the brain of living fetal guinea pigs during in utero exposure to unscanned pulsed ultrasound at ISPTA 2.8 W/cm2. Mean temperature increases of 4.9 degrees C close to parietal bone and 1.2 degrees C in the midbrain were recorded after 2-min exposures. When exposures were repeated on the same sites in each fetus after death, the corresponding mean temperature increases were 4.9 degrees C and 1.3 degrees C, respectively. Cerebral blood perfusion had little cooling effect on ultrasound-induced heating in the guinea pig fetus of 57-61 days gestational age.
Collapse
Affiliation(s)
- M M Horder
- Department of Veterinary Clinical Sciences, University of Sydney, NSW Australia
| | | | | | | | | |
Collapse
|
10
|
Horder MM, Barnett SB, Vella GJ, Edwards MJ, Wood AK. In vivo heating of the guinea-pig fetal brain by pulsed ultrasound and estimates of thermal index. ULTRASOUND IN MEDICINE & BIOLOGY 1998; 24:1467-1474. [PMID: 10385968 DOI: 10.1016/s0301-5629(98)00111-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Temperature was measured in the brain in live near-term fetal guinea pigs (62-66 d gestational age), during in utero exposure to a fixed beam of pulsed ultrasound at intensity ISPTA 2.82 W/cm2. Mean temperature increases of 4.3 degrees C close to parietal bone and 1.1 degrees C in the mid-brain were recorded after 2-min exposures. These values were lower (12%) than those obtained for ultrasound-induced heating near the bone in dead fetuses insonated in utero. A significant cooling effect of vascular perfusion was observed only when guinea pig fetuses reached late gestation, near term, when the cerebral vessels were well developed. The estimated value for the thermal index (TIB), as used in AIUM/NEMA output display standard, underestimated the measured temperature increase at the bone-brain interface. The ratio of measured temperature to the TIB is 1.3. A modification of the cranial thermal index provided a more reasonable, conservative, estimate of the temperature increase at a biologically significant point of interest at the brain-bone interface.
Collapse
Affiliation(s)
- M M Horder
- Department of Veterinary Clinical Sciences, University of Sydney, New South Wales, Australia
| | | | | | | | | |
Collapse
|