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.
References in periodicals archive ?
com provides an overall perspective of the actual sound attenuation value of various ear plug types compared to laboratory use of the same devices.
CT neck shows the fat as non-homogeneous tissue with low attenuation value consistent with fat.
It has been reported that each class of mineral in the stone gives a different attenuation value in NCCT.
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.
Difference of attenuation values in the affected kidney versus the unaffected kidney: The affected kidney having an attenuation value of about 5 HU less as compared to the unaffected side.
Each pixel (picture element) of a CT image has a CT attenuation value that is expressed in HU (Hounsfield Units), which range from 3095 HU for dense cortical bone to -1000 HU for CT density of air.
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.
Transmission data were reconstructed at a nuclear medicine workstation (eNTEGRA; GE Healthcare) to obtain cross-sectional attenuation images (256 x 256 matrix) in which each pixel represents the attenuation value of the corresponding tissue.
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.