For 60 years, a small number of people with a particular type of high blood pressure were never diagnosed.

The only available test used a catheter, which was difficult, so few hospitals even offered the test. In fact, 99% of such cases — until now — were never diagnosed because of the catheter test’s difficulty and its lack of availability.

But now, doctors at three United Kindgom hospitals have created and tested a new type of CT scan to light up tiny nodules in a key hormone-regulating gland and cure high blood pressure by removing them. Without the nodules being lit up by the dye, they were nearly impossible to see.

In most hypertension cases, the exact cause is unknown or can’t be pinned down, and the result is that those who have it must undergo lifelong treatment with drugs.

An estimated 5 to 20% of people with high blood pressure have a benign nodule in one of the adrenal glands that secretes a steroid hormone, called aldosterone [al-doss-tur-own]. The new scan uses a radioactive dye that sticks right to the aldosterone-producing nodule, lighting it up so surgeons can spot it and pluck it right out.

In these cases, the cause is a gene mutation in the adrenal glands, which results in excessive amounts of the steroid hormone aldosterone being produced.

Aldosterone causes the body to retain salt, driving blood pressure up.

Patients with too much aldosterone are resistant to the medicines most often used for high blood pressure, leaving them at risk for heart attacks and strokes.

While difficult, the old catheter test was as accurate as the new scan, but the new screening method is quick, painless and successful.