Splenomegaly — CT / MRI / US

CTMRIUSSplenic index (Prassopoulos 1997)

Assessment of splenic size and splenomegaly.

Applies to

Assessment of splenic enlargement on CT, MRI, or ultrasound in an adult

Does not apply to

Pediatric patients (use age- and height-specific references)
Focal splenic lesions (characterize separately)

What to report

Tap an item to check it off while dictating.

1.Craniocaudal length
Longest dimension; > 13 cm on ultrasound indicates splenomegaly. Report the single length even when volumetry is not performed.
2.Width and thickness
Transverse width and AP thickness for the splenic index (length × width × thickness).
3.Splenic index
Product of the three dimensions; normal ≈ 120–480 cm³. Report the index or an estimated volume.
4.Contour and accessory spleen
Note lobulation and any splenule/accessory spleen, and homogeneity of enhancement.
5.Associated findings
Portal hypertension signs, varices, lymphadenopathy, or diffuse marrow/organ disease that suggest an etiology.

Scores & calculators

Splenic index & volume

Splenic index and estimated volume from three orthogonal dimensions.

Length (craniocaudal)

Width (transverse)

Thickness (AP)

Complete the inputs to see the result.

Splenic index = length × width × thickness (cm); normal ≈ 120–480 cm³. Estimated volume = 0.524 × L × W × Th. A craniocaudal length > 13 cm on ultrasound also indicates splenomegaly. Use pediatric-specific references under 18 years.

Ellipsoid volume

Volume of an ellipsoid lesion or organ from three orthogonal diameters.

Length

Width

Height

Complete the inputs to see the result.

Ellipsoid formula V = (π/6) × L × W × H. 1 cm³ = 1 mL.

Sources

Splenic index and volume — Prassopoulos P et al. Eur Radiol (1997)

Content review: Content pending clinical review · 2026-07-10

Educational reference for trained clinicians. Verify every result against the cited original guideline before use. Not a substitute for clinical judgment or medical advice.