| Method . | Criteria favoring a benign mass . | Strength of evidenceb . |
|---|---|---|
| Noncontrast CT | ≤ 10 HUc | ⊕⊕⊕○ |
| FDG-PET/CT | Absence of FDG uptake or uptake less than the liverd | ⊕○○○ |
| MRI—chemical shift | Loss of signal intensity on out-phase imaging consistent with lipid-rich adenoma | ⊕○○○ |
| CT with delayed contrast media washoute | Relative washout > 58%f | ⊕○○○ |
| Method . | Criteria favoring a benign mass . | Strength of evidenceb . |
|---|---|---|
| Noncontrast CT | ≤ 10 HUc | ⊕⊕⊕○ |
| FDG-PET/CT | Absence of FDG uptake or uptake less than the liverd | ⊕○○○ |
| MRI—chemical shift | Loss of signal intensity on out-phase imaging consistent with lipid-rich adenoma | ⊕○○○ |
| CT with delayed contrast media washoute | Relative washout > 58%f | ⊕○○○ |
These criteria apply only for masses with homogenous appearance, or masses that have other clear characteristics consistent with benign disease, eg, myelolipoma. A homogeneous mass is defined as a lesion with uniform density or signal intensity throughout. The measurements/region of interest (ROI) should include at least 75% of a lesion without contamination by tissues outside the adrenal lesion. Nonhomogeneous lesions should not be subjected to MRI or washout CT for further characterization.
The strength of recommendation based on our systematic review on this topic (Section 4.1.1) and our personal experience.
The majority of adrenal masses with HU 11-20 are also benign, especially in patients without history of extra-adrenal malignancy (see Section 4.1.1 and Reasoning R.2.4 for details).
Certain metastasis (eg, from kidney cancer or low grade lymphoma) may be FDG negative.
There is no clear evidence about the best time interval. However, experienced adrenal radiologists prefer 15 min over 10 min.
This cutoff based on a single study with only 253 adrenal tumors72 and has to be judged with caution and several older studies suggest a cutoff of 40%.
Abbreviation: HU, Hounsfield unit.
| Method . | Criteria favoring a benign mass . | Strength of evidenceb . |
|---|---|---|
| Noncontrast CT | ≤ 10 HUc | ⊕⊕⊕○ |
| FDG-PET/CT | Absence of FDG uptake or uptake less than the liverd | ⊕○○○ |
| MRI—chemical shift | Loss of signal intensity on out-phase imaging consistent with lipid-rich adenoma | ⊕○○○ |
| CT with delayed contrast media washoute | Relative washout > 58%f | ⊕○○○ |
| Method . | Criteria favoring a benign mass . | Strength of evidenceb . |
|---|---|---|
| Noncontrast CT | ≤ 10 HUc | ⊕⊕⊕○ |
| FDG-PET/CT | Absence of FDG uptake or uptake less than the liverd | ⊕○○○ |
| MRI—chemical shift | Loss of signal intensity on out-phase imaging consistent with lipid-rich adenoma | ⊕○○○ |
| CT with delayed contrast media washoute | Relative washout > 58%f | ⊕○○○ |
These criteria apply only for masses with homogenous appearance, or masses that have other clear characteristics consistent with benign disease, eg, myelolipoma. A homogeneous mass is defined as a lesion with uniform density or signal intensity throughout. The measurements/region of interest (ROI) should include at least 75% of a lesion without contamination by tissues outside the adrenal lesion. Nonhomogeneous lesions should not be subjected to MRI or washout CT for further characterization.
The strength of recommendation based on our systematic review on this topic (Section 4.1.1) and our personal experience.
The majority of adrenal masses with HU 11-20 are also benign, especially in patients without history of extra-adrenal malignancy (see Section 4.1.1 and Reasoning R.2.4 for details).
Certain metastasis (eg, from kidney cancer or low grade lymphoma) may be FDG negative.
There is no clear evidence about the best time interval. However, experienced adrenal radiologists prefer 15 min over 10 min.
This cutoff based on a single study with only 253 adrenal tumors72 and has to be judged with caution and several older studies suggest a cutoff of 40%.
Abbreviation: HU, Hounsfield unit.
This PDF is available to Subscribers Only
View Article Abstract & Purchase OptionsFor full access to this pdf, sign in to an existing account, or purchase an annual subscription.
