Understanding AUA Readings for Prostate Volume on Ultrasound

Understanding AUA on Ultrasound: Assessing the Prostate

When looking at ultrasound results for the prostate gland, you may come across the abbreviation AUA. But what exactly does AUA stand for in this context and what information does it provide? Let's take a closer look at how ultrasounds are used to evaluate the prostate and the meaning of AUA readings.

The Prostate Gland

The prostate is a small gland located below the bladder in men. It surrounds the urethra, which carries urine from the bladder out through the penis. The main functions of the prostate include:

• Producing fluid that nourishes and protects sperm
• Contracting to expel semen during ejaculation
• Regulating urine flow by pressing on the urethra

As men age, the prostate tends to grow larger. An enlarged prostate, known medically as benign prostatic hyperplasia (BPH), can squeeze the urethra and cause urinary symptoms.

Ultrasounds for Prostate Evaluation

Ultrasound imaging uses sound waves to create pictures of internal body structures. It can be used to visually assess the size and anatomy of the prostate gland. There are two main types of ultrasounds used:

• Abdominal ultrasound: A wand is moved over the abdomen to image the prostate through the skin, bladder, and rectal wall.
• Transrectal ultrasound (TRUS): A probe is inserted into the rectum to image the prostate up close.

In addition to size, ultrasounds allow assessment of prostate shape, contours, and consistency. It can also detect abnormal growths like cysts or tumors.

Measuring Prostate Volume

One of the main uses of TRUS is to measure prostate volume. Volume refers to the three-dimensional size of the prostate gland.

Why measure volume? Enlarged prostate volume can indicate underlying conditions causing prostate enlargement. It also guides treatment options and allows monitoring of size changes over time.

During a TRUS, the ultrasound technician will take measurements of prostate width, height, and depth. Prostate volume is then estimated using a calculation that multiplies these numbers together.

What is AUA?

This brings us to AUA. In ultrasound reports, AUA stands for "estimated prostate volume" based on the dimensions observed. You will see it reported like: AUA: 45 cc

The cc refers to cubic centimeters, the unit used for prostate volume. A normal prostate is usually 20-30 cc in younger men.

An AUA reading higher than this indicates prostate enlargement. For example, an AUA of 45 cc would signify moderate enlargement.

AUA Ranges

Here are the general guidelines for AUA readings on ultrasound:

• 30 cc or less = Normal prostate volume
• 30-50 cc = Moderate enlargement
• 50-80 cc = Severe enlargement
• Over 80 cc = Very severe enlargement

The higher the AUA number, the larger the prostate volume. Your doctor will interpret your specific AUA in relation to your symptoms and health history.

Understanding TRUS Reports

Looking at the full TRUS report provides added context beyond just the AUA reading. The radiologist may also comment on:

• Prostate shape - enlargement on one or both sides?
• Zonal anatomy - transition zone enlarged?
• Urethra - compressed or deviated?
• Bladder thickness - related to obstruction?
• Post-void residue - urine left after voiding?
• Other findings like cysts, lesions, or asymmetry

These details along with prostate volume help determine if BPH or other prostate problems are present.

Correlating AUA with PSA Levels

In some cases, the AUA may also be compared with PSA levels. PSA stands for prostate-specific antigen, a protein marker used to screen for prostate cancer risk.

Studies have shown a general correlation between higher PSA levels and larger prostate volumes. However, an elevated PSA may warrant further testing even if the AUA is normal.

Tracking Changes over Time

Sequential AUAs on repeat ultrasounds allow your doctor to monitor changes in prostate volume. This can assess response to medications or natural approaches to shrink an enlarged prostate.

A significantly rising AUA indicates continued prostate enlargement that may require surgical treatment if causing worsening urinary problems.

AUA in Prostate Cancer Screening

Although TRUS is often used for prostate cancer detection, AUA itself has limited usefulness for diagnosing cancer. A very high AUA could raise suspicion in combination with other risk factors.

However, prostate cancer can also be present with normal AUAs. More definitive tests like MRI scans and prostate biopsies are needed to properly evaluate for prostate cancer.

Limitations of AUA Readings

While the AUA provides a numeric estimate of prostate size, be aware that TRUS has limitations:

• User-dependent - relies on technician skill and experience
• Semi-objective method of measurement
• Cannot differentiate precise anatomy
• Not as accurate for determining volume as MRI

Take the AUA as one data point, but understand the bigger picture with input from your urologist or provider.

Key Takeaways

In summary, key things to know about AUA prostate measurements on ultrasound include:

• AUA stands for estimated prostate volume in cc
• Higher AUAs indicate larger prostate enlargement
• AUA interpretations account for age and other factors
• Compare to PSA levels and clinical picture for added context
• Monitor AUAs over time to track changes
• Has limitations so should not be used alone

Discuss your AUA results with your doctor to understand what prostate volume changes mean for your prostate health and symptoms.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.