Splenic Index Calculator (CT Scan)
Calculate the Splenic Index to diagnose splenomegaly using CT measurements. Includes visual references and standard thresholds for radiologists.
About
Radiologists and clinicians use the Splenic Index to objectively quantify spleen size and diagnose splenomegaly. While linear length is often used as a quick proxy, the volumetric index provides a more accurate correlation with actual splenic volume. This tool simplifies the calculation derived from standard axial and coronal CT images. It is particularly useful in oncology staging, hematologic disorders, and trauma assessment where precise organ tracking is required.
The calculation requires three orthogonal measurements: length, width, and thickness. Values exceeding the standard threshold suggest enlargement, warranting further clinical correlation. Accuracy in measurement placement (e.g., measuring width at the splenic hilum) is critical for valid results.
Formulas
The Splenic Index (SI) is the product of the three maximum dimensions of the spleen measured in centimeters. It is a dimensionless unit, though it strongly correlates with volume.
Where:
- L = Length (Craniocaudal max)
- W = Width (Transverse max)
- T = Thickness (Anteroposterior max)
Reference Data
| Parameter | Value / Range | Clinical Significance |
|---|---|---|
| Normal Splenic Index | 120 - 480 | Physiological range in healthy adults. |
| Splenomegaly Threshold | > 480 | Indicates enlargement (Splenomegaly). |
| Massive Splenomegaly | > 1000 | Often seen in myelofibrosis or malaria. |
| Average Length (L) | 12 - 15 cm | Max Craniocaudal dimension. |
| Average Width (W) | 7 - 10 cm | Max Transverse dimension. |
| Average Thickness (T) | 3 - 5 cm | Max Anteroposterior dimension. |
| Correlated Volume | V ≈ 30 + 0.58 × Index | Estimates true volume in cm3. |
| Modality | CT / MRI | Standard cross-sectional imaging. |