Table 3 Acoustic radiation force impulse (ARFI) and B-mode multiparametric ultrasound (mpUS) index of suspicion (IOS) lesion ranking criteria. IOS 1: clinically significant cancer is highly unlikely to be present. IOS 2: clinically significant cancer is unlikely to be present. IOS 3: the likelihood of clinically significant cancer is equivocal. IOS 4: clinically significant cancer is likely to be present. IOS 5: clinically significant cancer is highly likely to be present
From: Evaluation of 3D ARFI imaging of prostate cancer: diagnostic reliability and concordance with MpMRI
Peripheral Zone | Contralateral Symmetry | Intensity and Contrast | Texture | Margin |
|---|---|---|---|---|
IOS 1 | Symmetric or Asymmetric | Hyper- or Iso-intense, low contrast | Homogenous | Distinct or Indistinct |
IOS 2 | Asymmetric | Hypointense, low-to-medium contrast | Heterogeneous | Indistinct |
IOS 3 | Asymmetric | Hypointense, medium contrast | Heterogenous | Indistinct |
IOS 4 | Asymmetric | Hypointense, medium-to-high contrast in 3 views | Predominantly homogenous but with some heterogeneity present | Distinct |
IOS 5 | Asymmetric | Hypointense, high contrast in 3 views | Homogeneous in all 3 views | Distinct |
Transition Zone | Contralateral Symmetry | Intensity and Contrast | Texture | Margin |
IOS 1 | Symmetric or Asymmetric | Hyper- or Iso-intense, low contrast | Homogeneous | Distinct or Indistinct |
IOS 2 | Asymmetric | Hypointense, medium contrast | Heterogeneous | Indistinct or Encapsulated nodule (BPH) |
IOS 3 | Asymmetric | Hypointense, medium-to-high contrast | Homogeneous | Indistinct |
IOS 4 | Asymmetric | Hypointense, high contrast in 3 views | Predominantly homogeneous texture but could have some heterogeneity present | Distinct (not encapsulated/nodular) |
Central Zone | Contralateral Symmetry | Intensity and Contrast | Texture | Margin |
IOS 1 | Symmetric or Asymmetric | Hyper- or Iso-intense, low contrast | Homogeneous | Distinct or Indistinct |
IOS 2 | Symmetric | Hypointense, high contrast | Homogeneous | Distinct or Indistinct |
IOS 3 | Asymmetric | Hypointense, high contrast | Homogeneous | Distinct |