Free radiology calculators for the reading room
Enter values or choose factors to see a calculation, with comparisons drawn from published sources where applicable. Every page stays dark for the reading room.
Results
- Absolute washout APWAbsolute percentage washout: 100 × (Enhanced − Delayed) / (Enhanced − Unenhanced). Decides the category when an unenhanced value is available; adenoma range ≥60% (ACR 2017).
- 56.7%
- Relative washout RPWRelative percentage washout: 100 × (Enhanced − Delayed) / Enhanced. Decides the category only when no unenhanced value is available; adenoma range ≥40% (ACR 2017).
- 37.3%
Washout category
Decision order, top to bottom| Step | Criterion | Meaning | This lesion |
|---|---|---|---|
| W1Step 1 of this calculator’s decision order, applied top to bottom. A Radikulus step label, not an ACR category. | Unenhanced ≤10 HUUnenhanced attenuation at or below 10 HU, checked first. | Low unenhanced attenuationUnenhanced attenuation ≤10 HU is consistent with benign low-density features. For a homogeneous lesion, ESE recommends no further adrenal imaging; possible entities include lipid-rich adenoma, myelolipoma and a fluid-filled cyst. | |
| W2Step 2 of this calculator’s decision order, applied top to bottom. A Radikulus step label, not an ACR category. | Early and delayed enhancement <10 HULess than 10 HU change from unenhanced on the early phase, without delayed enhancement ≥10 HU. | Washout not applicableNo measurable early enhancement (<10 HU change); washout is not applicable. ACR considers a mass without enhancement a cyst or hemorrhage requiring no follow-up imaging. | |
| W3Step 3 of this calculator’s decision order, applied top to bottom. A Radikulus step label, not an ACR category. | Delayed > enhancedDelayed attenuation exceeds enhanced attenuation. | No washout: indeterminateNo washout: not adenoma-typical — indeterminate. | |
| W4Step 4 of this calculator’s decision order, applied top to bottom. A Radikulus step label, not an ACR category. | APW ≥60%Absolute percentage washout: 100 × (Enhanced − Delayed) / (Enhanced − Unenhanced). Decides the category when an unenhanced value is available; adenoma range ≥60% (ACR 2017). | Adenoma rangeWashout at or above the adenoma threshold. ESE 2023 (PMID 37318239): evidence for accuracy of these cutoffs in adrenal incidentalomas was very low. | |
| W5Step 5 of this calculator’s decision order, applied top to bottom. A Radikulus step label, not an ACR category. | APW <60%Absolute percentage washout: 100 × (Enhanced − Delayed) / (Enhanced − Unenhanced). Decides the category when an unenhanced value is available; adenoma range ≥60% (ACR 2017). | IndeterminateIndeterminate by washout criteria (absolute washout <60%). | APWAbsolute percentage washout: 100 × (Enhanced − Delayed) / (Enhanced − Unenhanced). Decides the category when an unenhanced value is available; adenoma range ≥60% (ACR 2017).56.7% |
Washout criteria apply only to homogeneous masses (ESE 2023)Washout characterization assumes a homogeneous mass. ESE 2023 advises against using washout CT to characterize nonhomogeneous lesions (Table 4).
6–12-month follow-up CT may be considered (ACR 2017)When dedicated adrenal CT cannot establish a benign diagnosis, 6–12-month follow-up CT to document stability may be considered, depending on clinical context (ACR 2017).
Imaging does not determine hormonal function. See endocrine evaluation guidance (ACR 2017; ESE 2023).
Calculators
Body CT
Chest CT
Organ volumes
- Prostate Volume & PSA Density CalculatorEllipsoid prostate volume with optional PSA density.
- Ovarian Volume CalculatorOvarian volume from three dimensions, with Pavlik’s published limits and a conditional PCOM volume assessment for eligible inputs.
- Uterus Volume CalculatorUterine volume from three measurements, with optional comparison to Kelsey 2016 age-reference centiles.
- Ellipsoid Organ Volume CalculatorVoluMetricsGeometric volume estimates from three diameters, with organ presets and selectable prostate and testis formulas.
Musculoskeletal
How the calculators are built
- Sources you can see
- Each calculator names the guidelines or studies it uses, links to the sources and says when it was last checked for newer criteria.
- Calculations and context
- Results show the calculation, comparisons drawn from published sources where applicable, and relevant imaging guidance. Clinical guidance stays in the article and linked sources.
- Simulate cases are labelled
- Simulate loads published cases, cited by PMID, or reviewed hypothetical cases labelled as hypothetical.
- Sources and calculation tests
- Each calculator cites its sources. The test suite includes comparisons with a separate Python reference built from a shared specification.