Mi And Ti Output Display Accuracy; Factors That Contribute To Display Uncertainty - FujiFilm SonoSite Edge II User Manual

Table 10-3: TI or MI  1.0 (continued)
Transducer Model
TEExi/8-3
Even when MI is less than 1.0, the system provides a continuous real-time display of MI in all imaging modes, in
increments of 0.1.
The system meets the output display standard for TI and provides a continuous real-time display of TI in all imaging
modes, in increments of 0.1.
The TI consists of three user-selectable indices, and only one of these is displayed at any one time. In order to display TI
properly and meet the ALARA principle, the user selects an appropriate TI based on the specific exam being
performed. FUJIFILM SonoSite provides a copy of AIUM Medical Ultrasound Safety, which contains guidance on
determining which TI is appropriate. Refer to
Note

MI and TI output display accuracy

The accuracy result for the MI is stated statistically. With 95% confidence, 95% of the measured MI values will
be within +18% to -25% of the displayed MI value, or +0.2 of the displayed value, whichever value is larger.
The accuracy result for the TI is stated statistically. With 95% confidence, 95% of the measured TI values will be
within +21% to -40% of the displayed TI value, or +0.2 of the displayed value, whichever value is larger. The
values equate to +1dB to -3dB.
A displayed value of 0.0 for MI or TI means that the calculated estimate for the index is less than 0.05.

Factors that contribute to display uncertainty

The net uncertainty of the displayed indices is derived by combining the quantified uncertainty from three
sources: measurement uncertainty, system and transducer variability, and engineering assumptions and
approximations made when calculating the display values.
Measurement errors of the acoustic parameters when taking the reference data are the major source of error
that contributes to the display uncertainty. The measurement error is described in
precision and uncertainty"
The displayed MI and TI values are based on calculations that use a set of acoustic output measurements that
were made using a single reference ultrasound system with a single reference transducer that is representative
of the population of transducers of that type. The reference system and transducer are chosen from a sample
population of systems and transducers taken from early production units, and they are selected based on
Output display
2D/
Index
M Mode
MI No
TIC, TIB, or TIS No
"Related guidance documents"
For output display information for the P11x transducer, refer to the P11x Transducer
User Guide, included with the P11x transducer.
on page 234.
CPD/
PW Doppler
Color
No No
No Yes
on page 182.
"Acoustic measurement
CW Doppler
No
Yes
181