Title:Assessment of Thermal and Mechanical Indices as Acoustic Output Parameters
Used in Obstetric Ultrasound in Saudi Arabia
Volume: 20
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
Affiliation:
- Department of Diagnostic Radiology, College of Applied Medical Sciences, Taibah University, Al-Madinah Al-Munawwarah, Kingdom of Saudi
Arabia
Keywords:
Thermal index bone (TIb), Mechanical index (MI), B-mode, M-mode, Color doppler, Pulsed doppler.
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.