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Adrenal Washout Calculator for CT Scan

An adrenal washout calculator is a tool that helps to estimate the degree of adrenal gland function based on the results of a computed tomography (CT) scan. The adrenal glands are two small endocrine glands located on top of the kidneys that produce hormones that play important roles in various bodily functions. The adrenal CT washout calculator uses the results of a CT scan to calculate the percentage washout of the contrast material that is used during the scan. The contrast material is injected into a vein to help highlight certain structures in the body during the scan. The washout percentage is calculated by comparing the amount of contrast material in the adrenal gland at the beginning of the scan to the amount present at the end of the scan. The adrenal CT washout calculator is typically used to assess the function of the adrenal glands in patients who may have a problem with their adrenal gland function, such as adrenal insufficiency or Cushing's syndrome. It can also be used to monitor the effectiveness of treatment for these conditions.

Adrenal Washout Calculator for CT Scan

Adrenal Washout Calculator for CT Scan

Pre-contrast HU

60-75 Second Post-contrast HU

15 Minute Delayed HU

Calculate

Value

Value

How It Works

The adrenal washout calculator uses CT imaging data to measure the attenuation (density) of the adrenal lesion at different time points:

• Pre-HU: Pre-contrast (unenhanced) CT attenuation
• Post-HU: Enhanced (contrast) CT attenuation, typically taken 60-70 seconds after contrast administration
• Delayed HU: Delayed CT attenuation, usually taken 10-15 minutes after contrast administration

• Absolute Washout Percentage (AWP) = 100 x ((Post HU - Delayed HU) / (Post HU - Pre HU))

• Relative washout (RWP) = 100 x ((Post HU - Delayed HU) / (Post HU))

Interpreting Results

• Absolute percentage washouts greater than 60% suggests an adenoma.
• Relative percentage washouts greater than 50% suggets an adenoma.
• An adrenal lesion greater than 120 HU with washout shouldn't be diagnosed as an adenoma.
• Malignant lesions usually exhibit lower washout percentages, which suggests the need for more investigation.

Learn more on the BackTable VI Podcast

BackTable is a knowledge resource for physicians by physicians. Get practical advice on the Adrenal Washout Calculator for CT Scan and how to build your practice by listening to the BackTable VI Podcast, reading exclusing BackTable Articles, and following the work of our Contributors.

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