ICH Volume Calculator

This ICH volume calculator estimates the size of a parenchymal hemorrhage based on a CT scan (computed tomography scan). All you need to know are the dimensions of the bleed as determined by the scan. The tool applies the ABC2 (also known as ABC CT) formula.

What is the measure of ABC, and what exactly does this mysterious abbreviation stands for? Read the article below to get the answers. Also, we included an explanation of this ABC calculator's use with a practical example. Use our ICH score calculator to assess the severity and mortality after intracerebral hemorrhage.

We try our best to make our Omni Calculators as precise and reliable as possible. However, this tool can never replace a professional doctor's assessment. All information on this website is for informational purposes only and is not intended to serve as a substitute for medical consultation. Always consult your results with a healthcare provider.

ABC CT comes from a simplified formula that physicians use to estimate the volume of a bleed. CT stands for computed tomography, the imaging method we use to estimate said volume. The ABC formula is as follows:

ICH volume = A × B × C × slices / 2,

where,

• A — Maximum length;
• B — Width perpendicular to A on the same head CT slice;
• C — Width of one slice; and
• slices — Number of slices with hemorrhage.

The proper ABC2 formula is more developed than the one above:

ICH volume = A × B × C × slices / hemorrhage shape

The hemorrhage shape can be either round/ellipsoid (and therefore equal to 2) or irregular/separated/multinodular (equal to 3).

Note that the volume of an ellipsoid is 4/3 × π × (A/2) × (B/2) × (C/2). With a rough estimation of π ~3, the volume becomes A×B×C/2.

A parenchymal hemorrhage, also known as intracerebral bleeding, may be caused by various chronic and acute conditions. Among the most common health issues that contribute greatly to the risk of hemorrhage is hypertension — elevated blood pressure may result in the tearing of arteries' walls inside the skull. Check if the blood pressure is within the recommended values with blood pressure calculator.

What else may cause an ICH?

• Drugs that influence the INR, such as heparin and warfarin used to prevent clots in heart and stroke conditions, may cause ICH. Also, alcohol, cocaine, and other illicit drugs. You can estimate your INR level with the INR calculator;
• Arteriovenous malformation;
• An aneurysm;
• Head trauma, fractures, penetrating wounds, car accidents, even if there is no open wound in the skull;
• Bleeding disorders: hemophilia, sickle cell anemia, DIC, thrombocytopenia;
• Tumors, such as angiomas and metastatic tumors, as they are highly vascularized;
• Amyloid angiopathy; and
• Nothing - bleeding may be spontaneous.

To use this ICH volume calculator, all you need is some data, preferably data derived from a head CT scan.

1. Measure the length (A) and width (B) of the bleeding.

2. Count the number of CT scan slices with bleeding (C) and the approximate width of each slice. If the area of hemorrhage covers ≥75% of the slice, it counts as one slice. Similarly, if the area of bleeding is between 25 and 75%, it counts as 0.5 slices. Otherwise, the slice doesn't count.

You can choose how many slices of which type you have, and the number of slices is calculated automatically in the advanced mode.

3. Finally, choose the hemorrhage's shape, whether it's ellipsoid, round, separated, multinodular, or irregular.

The formula to calculate ABC CT - based is simple:

ICH volume = A × B × C × slices / hemorrhage shape

For ellipsoid and round shapes, hemorrhage shape is substituted by 2. In the case of a separated, multinodular, or irregular shape, use 3 instead.

The result is the ICH volume in either ml, mm³, or cm³.

An intracerebral hemorrhage volume of >50-60 mL is a poor prognostic marker.

Let's work on an example. We have 65-year-old Robert, admitted to the Neurology Department because he is having trouble moving the right side of his body after falling from a chair and knocking himself unconscious. The physicians, suspecting a stroke, decided to do a head CT scan and discovered a major parenchymal hemorrhage. How big? Well, that's what they're trying to figure out now with the ABC formula from this ICH volume calculator.

• Length: 5 cm;
• Width: 3 cm;
• CT scan slice thickness: 2 mm;
• Number of slices: 40; and
• Shape: Ellipsoid.

ICH volume = 5 × 3 × 0.2 × 40 / 2

ICH volume = 60 mL³