PET/MRI may improve diagnosis of Cushing disease

PET/MRI could become the diagnostic method of choice over MRI alone for identifying small pituitary tumors associated with Cushing disease, according to a study published March 21 in the Journal of Nuclear Medicine.

In patients diagnosed with the disease yet who had inconclusive MRI results, PET/MRI was positive in 100% of cases, noted lead author Ilanah Pruis, a doctoral student at Erasmus University Medical Center in Rotterdam, Netherlands.

“This multimodal imaging technique provides a welcome improvement for diagnosis, planning of surgery, and clinical outcome in patients with Cushing disease,” the authors wrote.

Cushing disease is characterized by small tumors in pituitary glands, which causes them to secrete excess cortisol, the authors explained. While it is a rare disease, over time it can cause severely disabling conditions, such as high blood pressure or type II diabetes.

Currently, guidelines recommend the use of MRI and inferior petrosal sinus sampling (IPSS) to diagnose these tumors. IPSS is an invasive procedure in which cortisol hormone levels are sampled from the veins that drain the pituitary gland.

In up to 40% of patients, however, MRI is inconclusive, as the lesions are smaller than 10 millimeters in diameter. Even advanced MRI techniques, such as dynamic perfusion imaging, can leave small lesions undetected in up to one third of patients, the authors noted.

In preclinical work, PET imaging using a radiotracer named F-18 FET has been shown to bind with high affinity to a molecular target in pituitary tumors, and in this study, the researchers aimed to test this technique combined with MRI in a multimodal approach.

The researchers analyzed results from 22 patients (68% women; mean age 48 years) who underwent F-18 FET PET/MRI at Erasmus MC between February 2021 and December 2022. All patients showed a clear pituitary tumor F-18 FET-PET/MRI, whereas reading of the MRI alone yielded a suspected lesion in only 50%, the authors found.

T1-weighted postgadolinium MR images (A and C) and F-18 FET-PET/MR images (B and D) centered at pituitary before (A and B) and after (C and D) transsphenoidal surgery. This patient with Cushing disease showed clear focal uptake (B) but no clear lesion on previously obtained and accompanying MRI (A). Postoperative tissue analysis did confirm resection of small pituitary adenoma/PitNET, and postoperative F-18 FET-PET showed no residual uptake (D). Image courtesy of the Journal of Nuclear Medicine.T1-weighted postgadolinium MR images (A and C) and F-18 FET-PET/MR images (B and D) centered at pituitary before (A and B) and after (C and D) transsphenoidal surgery. This patient with Cushing disease showed clear focal uptake (B) but no clear lesion on previously obtained and accompanying MRI (A). Postoperative tissue analysis did confirm resection of small pituitary adenoma/PitNET, and postoperative F-18 FET-PET showed no residual uptake (D). Image courtesy of the Journal of Nuclear Medicine.

Importantly, 16 patients underwent treatment based on the results — either surgery, Gamma Knife, or CyberKnife therapy — with 12 of these patients achieving short-term remission, the authors noted.

“[F-18 FET-PET/MRI] is of great clinical value because it allows precision surgery and targeted Gamma Knife or CyberKnife therapy,” the group wrote.

The researchers noted that only one previous study evaluated F-18 FET-PET/MRI in these patients and that their study was limited, given the relatively small number of patients.

“Future studies will be directed at head-to-head comparisons of the performance of F-18 FET- PET and other diagnostic techniques, including advanced MRI sequences… preferably in patients at the time of initial clinical presentation,” the authors concluded.

A link to the full study can be found here.

From https://www.auntminnie.com/clinical-news/molecular-imaging/article/15667496/petmri-may-improve-diagnosis-of-cushing-disease

Day 5, Cushing’s Awareness Challenge

In Day 9 on April 9, 2015, I wrote about how we got the Cushing’s colors of blue and yellow.  This post is going to be about the first Cushing’s ribbons.

I was on vacation  in September, 2001 when SuziQ called me to let me know that we had had our first Cushie casualty (that we knew about).

On the message boards, Lorrie wrote: Our dear friend, Janice died this past Tuesday, September 4, 2001. I received an IM from her best friend Janine, tonight. Janine had been reading the boards, as Janice had told her about this site, and she came upon my name and decided to IM me. I am grateful that she did. She said that she knew that Janice would want all of us to know that she didn’t just stop posting.

For all of the newcomers to the board that did not know Janice, she was a very caring individual. She always had something positive to say. Janice was 36 years old, was married and had no children. She had a miscarriage in December and began to have symptoms of Cushing’s during that pregnancy. After the pregnancy, she continued to have symptoms. When discussing this with her doctor, she was told that her symptoms were just related to her D&C. She did not buy this and continued until she received the accurate diagnosis of Cushing’s Syndrome (adrenal) in March of 2001. Tragically, Janice’s tumor was cancerous, a very rare form of Cushing’s.

Janice then had her tumor and adrenal gland removed by open adrenalectomy, a few months ago. She then began chemotherapy. She was very brave through this even though she experienced severe side effects, including weakness and dizziness. She continued to post on this board at times and even though she was going through so much, she continued with a positive attitude. She even gave me a referral to a doctor a few weeks ago. She was my inspiration. Whenever I thought I had it bad, I thought of what she was dealing with, and I gained more perspective.

Janice was having difficulty with low potassium levels and difficulty breathing. She was admitted to the hospital, a CT scan was done and showed tumor metastasis to the lungs. She then was begun on a more aggressive regimen of chemo. She was discharged and apparently seemed to be doing well.

The potassium then began to drop again, she spiked a temp and she was again admitted to the hospital. She improved and was set to be discharged and then she threw a blood clot into her lungs. She was required to be put on a ventilator. She apparently was at high risk for a heart attack. Her husband did not want her to suffer anymore and did not want her to suffer the pain of a heart attack and so chose for the doctors to discontinue the ventilator on Tuesday. She died shortly thereafter.

Janice was our friend. She was a Cushie sister. I will always remember her. Janine asked me to let her know when we get the Cushing’s ribbons made as she and the rest of Janice’s family would like to wear them in her memory. She said that Janice would want to do anything she could to make others more aware of Cushing’s.

The image at the top of the page shows the first blue and yellow ribbon which were worn at Janice’s funeral.  When we had our “official ribbons” made, we sent several to Janice’s family.

Janice was the first of us to die but there have been more, way too many more, over the years.  I’ll write a bit more about that on Day 21.