Reshaping pituitary tumor diagnosis through advanced imaging

Aug. 05, 2026

For patients with pituitary tumors — especially those with hormone-related conditions such as Cushing disease — getting an accurate diagnosis can be challenging. In patients with Cushing disease, these tumors are often extremely small. And they may not be identified conclusively in up to 40% of patients using standard assessment. In these cases, negative imaging leaves uncertainty about tumor presence and location and results in lower remission rates following surgery.

At Mayo Clinic, a growing suite of advanced imaging approaches is helping close that gap — giving clinicians clearer answers and patients a more confident path forward.

"Improved imaging has a direct impact on care," says Jamie J. Van Gompel, M.D., a neurosurgeon at Mayo Clinic in Rochester, Minnesota. "Better preoperative visualization helps surgeons plan more precisely, avoid unnecessary exploration and focus treatment where it is most likely to succeed."

Expanding what imaging can reveal

While MRI remains the foundation of pituitary imaging, Mayo Clinic teams are using specialized sequences and complementary technologies to enhance what standard scans can show. These techniques are not used for every patient; rather, imaging is tailored on a case-by-case basis.

Why seeing the tumor matters

CISS sequence identifies occult pituitary tumor

A 39-year-old woman with Cushing disease underwent CISS imaging of her pituitary gland. Image (A) clearly shows a lesion on the right gland. On a standard MRI (Image B), however, the same tumor was much harder to see and not well defined. The tumor was later surgically removed and confirmed to be the cause of her condition.

STIR sequence reveals corticotroph adenoma

A 67-year-old woman with Cushing disease had a T2-weighted (A) and contrast enhanced 3D T1-weighted (B) scans that did not show a clear tumor. A STIR scan (C) was able to detect a small abnormal area in the pituitary gland. This was later confirmed to be a corticotroph adenoma.

Dynamic contrast-enhanced PCD-CT identifies pituitary adenomas

A 67-year-old woman with Cushing disease had a preoperative T1-weighted scan (left) that showed no definite lesion. Dynamic contrast-enhanced PCD-CT (right) shows two distinct lesions (arrows) in the right pituitary gland, found to be pathology-proved adenomas.

Because surgery is often the primary treatment for hormonally active tumors, knowing exactly where a lesion is before surgery matters. When imaging is inconclusive, patients may face additional testing, invasive diagnostic procedures or less targeted surgery.

One such approach is contrast-enhanced CISS/FIESTA imaging, an MRI sequence that improves the visual contrast between pituitary tumors and normal gland tissue. In a Mayo Clinic study of patients with Cushing disease, this technique identified discrete pituitary microadenomas in 94% of cases, compared with 65% identified using conventional contrast-enhanced T1-weighted MRI alone. The tumors also were more clearly defined, helping clinicians distinguish true lesions from surrounding tissue. The study results were published in the American Journal of Neuroradiology in 2025.

Advanced contrast-enhanced T2-weighted STIR imaging takes a different approach. By suppressing signals from the pituitary gland, an adenoma can become more conspicuous. This method may help not only with identifying small lesions but also with defining the extent of tumors, including whether they extend into the cavernous sinus. In published Mayo Clinic research in the American Journal of Neuroradiology in 2026, this technique successfully highlighted tumors that were not visible on standard MRI sequences, including lesions later confirmed during surgery.

In select cases, clinicians also may turn to a photon-counting detector CT. This advanced form of CT imaging provides detailed iodine maps of the pituitary region. This technology is particularly useful when MRI findings are inconclusive. As noted in a recent publication in the American Journal of Neuroradiology, 25 patients with Cushing disease underwent imaging at Mayo Clinic. In these patients, photon-counting detector CT accurately identified 92% of lesions compared with contrast-enhanced MRI, which detected 56% of lesions accurately.

"The real strength lies not in any single test, but in having multiple advanced options available," says Ian T. Mark, M.D., a radiologist at Mayo Clinic in Rochester, Minnesota.

From research to patient care

Several of these imaging techniques are in practice at Mayo Clinic. However, ongoing studies are exploring additional ways to improve tumor detection, particularly for patients whose imaging remains negative despite clear biochemical evidence of disease.

Two active clinical studies are evaluating emerging approaches:

Evaluation of Intraoperative Contrast Enhanced Ultrasound for the Identification of Pituitary Adenoma in Cushing Disease Compared to Other Pituitary Tumors.
FET PET/CT Imaging To Localize Pituitary Adenomas In Cushing Disease.

A clearer path forward

The clinical impact of advanced imaging can mean less uncertainty and more confidence in treatment decisions.

By combining clinical expertise and a broad range of imaging capabilities, Mayo Clinic teams are helping ensure that pituitary tumors once considered uncertain or unseen are increasingly identifiable, allowing care to move forward with greater clarity and purpose.