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Current Medical Imaging

Editor-in-Chief

ISSN (Print): 1573-4056
ISSN (Online): 1875-6603

Research Article

Assessment of Thermal and Mechanical Indices as Acoustic Output Parameters Used in Obstetric Ultrasound in Saudi Arabia

Author(s): Awadia Gareeballah*, Wafa Ghazai Alharbi, Taif Sami Alharbi, Rodina Mohammed Alhejaili, Nouf Ahmed Maashi, Fadwa Mohammed Al-Ahmadi, Sultan Abdulwadoud Alshoabi, Moawia Gameraddin, Maisa Elzaki, Walaa Alsharif, Raga Ahmed Abouraida, Mohammed Adam and Amel FH Alzain

Volume 20, 2024

Published on: 24 June, 2024

Article ID: e15734056312545 Pages: 7

DOI: 10.2174/0115734056312545240612095514

Price: $65

Abstract

Background: Patient safety is paramount in ultrasound procedures, particularly in obstetric ultrasounds involving both the mother and fetus. The thermal and mechanical indices (TI and MI) serve as crucial indicators of the acoustic output during ultrasound. Clinicians and specialists must know these indices and ensure they are within safe ranges. This study aimed to assess the parameters of acoustic output power employed in obstetric ultrasound (thermal and mechanical index).

Methodology: A cross-sectional observational study conducted at Maternity and Children's Hospital in Al-Madinah Al-Munawwarah, the data was collected from obstetric scanning of 411 pregnant females using a data collection sheet including gravida and women's age, gestational age, scan mode, scan time, and thermal and mechanical index (TI and MI) values.

Results: The study found that there were significant differences in safety indices measurement between different modes; in Pulsed Doppler, mean Thermal Index Bone (TIb) had the highest value (1.60±0.40), and the Mechanical Index (MI) was the lowest (0.68±0.33). There were insignificant differences in safety indices values in different modes in different trimesters. The thermal indices of soft tissue and bony structure (TIs and TIb) of brightness mode (B-mode) were constant in all trimesters, but the MI in the first trimester was lower than in the other trimesters.

Conclusion: This study concluded that the mean values of thermal indices used in B mode , M mode and Color Doppler lie within the Recommended limit of (BMUS) British Medical Ultrasound Society (below 0.7) except for Pulsed Doppler it was exceed 1.5. While for MI in different ultrasound modes except in pulsed Doppler the average values is higher than 0.7 which was recommended by (BMUS) British Medical Ultrasound Society and lower than 1.9 which was the maximum threshold approved by FDA (Food and drug Administration). The average scanning time is low (6.4 minute) reflect the safe use of ultrasound in obstetrics in this study.

[1]
Houston LE, Odibo AO, Macones GA. The safety of obstetrical ultrasound: A review. Prenat Diagn 2009; 29(13): 1204-12.
[http://dx.doi.org/10.1002/pd.2392] [PMID: 19899071]
[2]
How to interpret the ultrasound output display standard for diagnostic ultrasound devices: Version 3. J Ultrasound Med 2019; 38(12): 3101-5.
[http://dx.doi.org/10.1002/jum.15159] [PMID: 31736131]
[3]
Nelson TR, Fowlkes JB, Abramowicz JS, Church CC. Ultrasound biosafety considerations for the practicing sonographer and sonologist. J Ultrasound Med 2009; 28(2): 139-50.
[http://dx.doi.org/10.7863/jum.2009.28.2.139] [PMID: 19168764]
[4]
Sheiner E, Shoham-Vardi I, Pombar X, Hussey MJ, Strassner HT, Abramowicz JS. An increased thermal index can be achieved when performing Doppler studies in obstetric sonography. J Ultrasound Med 2007; 26(1): 71-6.
[http://dx.doi.org/10.7863/jum.2007.26.1.71] [PMID: 17182711]
[5]
ter Haar G. The new British Medical Ultrasound Society Guidelines for the safe use of diagnostic ultrasound equipment. Ultrasound 2010; 18(2): 50-1.
[http://dx.doi.org/10.1258/ult.2010.100007]
[6]
Abramowicz JS, Sheiner E. Ultrasound bioeffects and safety: What the practitioner should know. Sonography in Obstetrics & Gynecology: Principles and Practice. (7th ed.), McGraw Hill Professional 2010.
[7]
Ng KH. International guidelines and regulations for the safe use of diagnostic ultrasound in medicine. J Med Ultrasound 2002; 10(1): 5-9.
[http://dx.doi.org/10.1016/S0929-6441(09)60017-5]
[8]
Newnham JP, Evans SF, Michael CA, Stanley FJ, Landau LI. Effects of frequent ultrasound during pregnancy: A randomised controlled trial. Lancet 1993; 342(8876): 887-91.
[http://dx.doi.org/10.1016/0140-6736(93)91944-H] [PMID: 8105165]
[9]
Campbell JD, Elford RW, Brant RF. Case-control study of prenatal ultrasonography exposure in children with delayed speech. Obstet Gynecol Surv 1994; 49(7): 460-1.
[http://dx.doi.org/10.1097/00006254-199407000-00009]
[10]
Stark CR, Orleans M, Haverkamp AD, Murphy J. Short- and long-term risks after exposure to diagnostic ultrasound in utero. Obstet Anesthes Dig 1984; 4(4): 119.
[http://dx.doi.org/10.1097/00132582-198412000-00004] [PMID: 6198611]
[11]
Kieler H, Axelsson O, Haglund B, Nilsson S, Salvesen KÅ. Routine ultrasound screening in pregnancy and the children’s subsequent handedness. Early Hum Dev 1998; 50(2): 233-45.
[http://dx.doi.org/10.1016/S0378-3782(97)00097-2] [PMID: 9483394]
[12]
Salvesen K, Lees C, Abramowicz J, Brezinka C, Ter Haar G, Maršál K. ISUOG statement on the safe use of Doppler in the 11 to 13 +6‐week fetal ultrasound examination. Ultrasound Obstet Gynecol 2011; 37(6): 628-8.
[http://dx.doi.org/10.1002/uog.9026] [PMID: 21618313]
[13]
Sheiner E, Freeman J, Abramowicz JS. Acoustic output as measured by mechanical and thermal indices during routine obstetric ultrasound examinations. J Ultrasound Med 2005; 24(12): 1665-70.
[http://dx.doi.org/10.7863/jum.2005.24.12.1665] [PMID: 16301723]
[14]
Sheiner E, Hackmon R, Shoham-Vardi I, et al. A comparison between acoustic output indices in 2D and 3D/4D ultrasound in obstetrics. Ultrasound Obstet Gynecol 2007; 29(3): 326-8.
[http://dx.doi.org/10.1002/uog.3933] [PMID: 17265534]
[15]
Kamal Hagi S. Assessment of safety and exposure conditions during obstetric ultrasound at king abulaziz university hospital. J Am Sci 2012; 8(10): 287-90.
[16]
Nemescu D, Berescu A, Onofriescu M, Navolan DB, Rotariu C. Safety indices during fetal echocardiography at the time of first-trimester scan are machine dependent. PLOS ONE 2015; 10(5): e0127570.
[http://dx.doi.org/10.1371/journal.pone.0127570]
[17]
Barnett SB, Maulik D. Guidelines and recommendations for safe use of Doppler ultrasound in perinatal applications. J Matern Fetal Neonatal Med 2001; 10(2): 75-84.
[http://dx.doi.org/10.1080/jmf.10.2.75.84] [PMID: 11392597]
[18]
Miller DL. Safety assurance in obstetrical ultrasound. Semin Ultrasound CT MR 2008; 29(2): 156-64.
[http://dx.doi.org/10.1053/j.sult.2007.12.003] [PMID: 18450141]
[19]
Helmy S, Bader Y, Koch M, Tiringer D, Kollmann C. Measurement of thermal effects of doppler ultrasound: An in vitro study. PLoS One 2015; 10(8): e0135717.
[http://dx.doi.org/10.1371/journal.pone.0135717] [PMID: 26302465]
[20]
Guidelines for the safe use of diagnostic ultrasound equipment. BMUS Bulletin 2000; 8(3): 30-3.
[http://dx.doi.org/10.1177/1742271X0000800311]
[21]
Maeda K. Safety of ultrasound in obstetrics and gynecology. Donald School Textbook of Ultrasound in Obstetrics and Gynecology . Jaypee Brothers Medical Publishers (P) Ltd 2011; 1.
[http://dx.doi.org/10.5005/jp/books/11213_1]
[22]
The safe use of diagnostic ultrasound in obstetrics and gynecology. DSJUOG 2012; 6(3): 313-7.
[http://dx.doi.org/10.5005/jp-journals-10009-1254]
[23]
Sande RK, Matre K, Eide GE, Kiserud T. The effects of reducing the thermal index for bone from 1.0 to 0.5 and 0.1 on common obstetric pulsed wave Doppler measurements in the second half of pregnancy. Acta Obstet Gynecol Scand 2013; 92(7): 790-6.
[http://dx.doi.org/10.1111/aogs.12114] [PMID: 23418900]
[24]
Sheiner (F) E. Acoustic output as measured by mechanical and thermal indices during routine second trimester obstetrical ultrasound. Am J Obstet Gynecol 2005; 193(6): S157.
[http://dx.doi.org/10.1016/j.ajog.2005.10.628]

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