Page 87 - Ultrasonography in Prehospital and Emergency Medicine - Rein Ketelaars

Which ultrasound transducer type is best for diagnosing pneumothorax in pre-hospital care? 85
After we fitted the linear mixed model, we found significant differences in image quality between all three transducers. The image quality with the linear-array transducer was 1.78 higher than the image quality with the phased-array transducer on a 5-point Likert scale. These comparisons in image quality between transducers are displayed in Table 3.5.
The image quality was deemed too bad to make a diagnosis in ten cases: 8 of 330 phased-array transducer clips and 2 of 330 linear-array transducer clips. Of those, seven clips showed a pneumothorax and three showed normal lung sliding.
Table 3.5
Linear-array Linear-array Curved-array
Difference in image quality between transducer types
Compared transducers
Estimate [95% CI]
p value
vs Curved-array vs Phased-array vs Phased-array
0.53 [0.29, 0.76] 1.78 [1.56, 2.01] 1.25 [1.09, 1.42]
< .0001 < .0001 < .0001
This table presents the differences in reported image quality between a combination of two transducers, using a linear mixed model with a random intercept.
The image quality was reported on a 5-point Likert scale: 1, very poor; 5, very good.
A positive value indicates that the image quality was better with the left of the two compared transducers.
180 160 140 120 100
80 60 40 20
0
Figure 3.6
Image quality 1 = very poor 2
3
4
5 = very good
linear-array
curved-array
phased-array
Clustered bar count of the image quality rating per transducer type
After we fitted the linear mixed model we found a significant difference in image quality between all three trans- ducers (p < .0001) as displayed in Table 3.5.
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