The normal heart ratio, specifically the cardiothoracic ratio (CTR), typically falls between 0.42 and 0.50.
Understanding the Cardiothoracic Ratio (CTR)
The cardiothoracic ratio (CTR) is a measurement used in radiology to assess heart size in relation to chest size on a chest X-ray. It helps determine if the heart is enlarged (cardiomegaly).
How to Calculate CTR:
The CTR is calculated by dividing the maximum horizontal width of the heart by the maximum internal width of the chest at its widest point on a PA (Posterior-Anterior) chest radiograph.
Normal CTR Values:
| Condition | CTR Value | Interpretation |
|---|---|---|
| Normal Heart Size | 0.42-0.50 | Heart size is within the normal range. |
| Cardiomegaly | > 0.50 | May indicate an enlarged heart (cardiomegaly). |
Reference: Normal values range between 0.42 and 0.50... A value above 0.50 is considered abnormal and may indicate cardiomegaly [3].
Important Note: The cardiothoracic ratio should not be presented as a percentage, but as a ratio.
