ACR breast density
Brief definition
ACR breast density describes how much glandular and connective tissue your breast contains relative to fatty tissue. The classification of the American College of Radiology (ACR) has four levels — from a (very fatty tissue) to d (extremely dense glandular tissue). The category appears in every mammogram report, and it matters for two reasons.
What is behind this finding?
ACR a means the breast consists mostly of fatty tissue — tumors would be easy to spot on a mammogram. ACR b shows scattered glandular tissue. ACR c describes heterogeneously dense breasts — smaller findings can be masked. ACR d (extremely dense) means the sensitivity of mammography is markedly reduced, because tumor tissue and glandular tissue both appear white on the X-ray image. Density depends on your age, your hormones and your genes, and in most women it drops after menopause. Keep in mind that the category is a judgment call by the radiologist reading the scan, so it can shift slightly from one mammogram to the next.
What does this mean for you?
If you are ACR a or b, mammography picks up most of what there is to find, and routine screening is usually enough. If you are ACR c or, especially, d, it is worth knowing that mammography alone is less reliable for you; adding an ultrasound — or an MRI if your risk is elevated — may be a good idea. Dense tissue is also a moderate risk factor for breast cancer on its own, separate from the fact that it hides things. Talk with your gynecologist about the screening plan that fits your situation.
When is a second opinion worthwhile?
If you have dense breasts (ACR c or d) and the report also comes back unclear — a BI-RADS 3 or 4, say — a second opinion is especially valuable, because that combination is where diagnostic uncertainty peaks. A second read of your mammogram is also worth considering if breast cancer runs in your family. Second View gets you a radiological second opinion within 48 hours.
How can I request a second opinion?
1. Get in touch
Contact us through our platform.
2. A radiologist gets back to you
A board-certified radiologist contacts you personally and works with you to pin down exactly which question the second opinion should answer — and whether your existing images (MRI, CT, or X-ray) are suitable for a second read.
3. Transparent, upfront pricing
You then receive a firm quote — usually €70–150, depending on the type of exam.
4. The second reading
Once you approve and pay, our radiologists — all licensed to practice in Germany — review your images carefully and independently.
5. Your report & follow-up questions
Your report arrives digitally, written in plain, easy-to-understand language.
If anything is unclear, you can speak directly with the radiologist who read your images.
Tip:
Many private health insurers reimburse some or all of the cost of a radiological second opinion.
You’ll receive an invoice you can submit to your insurer. If you have German statutory health insurance (GKV), you currently pay for the second opinion yourself — statutory insurance does not cover it (Section 27b of the German Social Code, Book V).