attenuation value

attenuation value

A measure of an imaging beam’s reduction in intensity by the tissue through which it passes.
Examples, attenuation values Air has a negative AV; fluids have an AV up to the low 30s; non-calcified solid masses to the low 70s; calcified masses up to 100.
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11) An unenhanced CT (NC-CT) attenuation value of up to 10 HU has been shown to diagnose a lipid-rich adenoma with 71% sensitivity and 98% specificity, and is therefore used as the threshold below which adrenal lesions are considered to be definitively benign (Figure 5).
The attenuation value is denoted by the number following the hyphen in the Pasternack part number.
CT washout formulae for adenoma characterisation Percentage washout Formula Washout values (%) Adenoma Malignant Absolute % washout-APW (E-D)/(E-U) x 100 > 60 < 60 Relative % washout-RPW (E-D)/E x 100 > 40 < 40 E = enhanced attenuation value-60 seconds; D = delayed enhanced value-15 minutes; U = unenhanced attenuation value.
The differences in the mean sound pressure level resulted from the application of plants with different foliage types while the control group represented the relative attenuation value.
The attenuation value of the ROC is determined by its geometry (that is, the ratio of open to active surface area of the sectors) while the surface reflectivity has no effect on this value.
The smaller the difference between the measured site attenuation value and the ideal site attenuation (ideal value), the higher the quality of the anechoic chamber.
If the growth is not functioning, then it should be imaged using unenhanced CT to determine its attenuation value using Hounsfield units, as this will indicate whether it is lipid-rich or lipid-poor.
TSB-67 contains the limit attenuation value for each frequency step of 1 MHz.
That is the minimum light attenuation value for all f/1.
to establish the objective criteria for the HMCA sign, the authors concluded that an absolute attenuation value of 43 Hounsfield units (HU) of the abnormal MCA and a ratio of more than 1.
The CT attenuation value can also indicate the possible malignancy of an adrenal mass, the panel said.