1. Clinical evaluation of 11C-Met-avid pituitary lesions using a ZTE-based AC method
G. Delso, D. Gillett, W. Bashari, T. Matys,
I. Mendichovszky & M. Gurnell

2. The pituitary gland
The pituitary gland, or hypophysis, is an endocrine gland
located at the base of the brain,
suspended from the hypothalamus by a gray matter stalk.
It is housed by the hypophysial fossa of the sphenoid bone,
at the center of the middle cranial fossa.
The pituitary gland is approximately 13 mm in diameter
and 5 mm of height, weighting 500 mg.

3. Pituitary disease
The pituitary gland consists of two main lobes, anterior and posterior,
each releasing specific hormones that affect several bodily functions.
Overproduction or underproduction of a pituitary hormone
will affect the respective end-organ.

4. Pituitary disease Cushing’s (excess cortisol hormone)
Acromegaly (excess growth hormone)
Normal vs. acromegaly

5. Pituitary lesions Pituitary adenomas are tumors
that occur in the pituitary gland.
Pituitary adenomas represent 10% to 25%
of all intracranial neoplasms 
and the estimated prevalence rate
in the general population is approximately 17%.
Most adenomas are benign,
approximately 35% are invasive
and just 0.1% to 0.2 are carcinomas.
While pituitary adenomas are common,
affecting ~1:6 of the population,
clinically active adenomas
that require surgical treatment
affect ~1:1000 of the population.
Images courtesy of Dr. Bashari & Prof. Gurnell

6. Treatment: Trans-sphenoidal surgery (TSS)

7. Treatment: Trans-sphenoidal surgery (TSS)

8. Value of 11C-Methionine PET
Koulouri (2015). Eur J Endocrinol 173(4): M
Koulouri (2016). Eur J Endocrinol 175(5):
Value of 11C-Methionine PET
De novo Cushing’s disease
Cor SPGR + Gd, 1mm slices
[11C]-MET reflects amino acid transport

9. Value of 11C-Methionine PET
De novo Cushing’s disease
Cor SPGR + Gd, 1mm slices
[11C]-MET reflects amino acid transport

10. The OPTIMUM Study
“Optimising Pituitary Tumor Imaging with PET/MR Using 11C-Methionine.”
Discovery 690 PET/CT
SIGNA PET/MR

11. Patient summary 23 patients with clinically active pituitary lesions.
16 female, 7 male
Weight: 84 ± 23 kg
Age: 41 ± 14 kg
15 patients returned for a second session post-therapy.
Delay: 28 ± 1 days.

12. Imaging protocol PET/CT imaging on GE Discovery 690
Dose: 409 ± 44 MBq 11C-Methionine (half-life 20 minutes)
Start: 19 ± 2 minutes post-injection.
Duration: 20 minutes.
PET/MR imaging on GE SIGNA PET/MR
No additional dose
Start: 74 ± 22 minutes post-injection.
Duration: 40 minutes.

13. MR protocol FOCUS DWI BRAVO T1 BRAVO T2 CUBE FIESTA-C DCE LAVA-FLEX
FSPGR
ZTE
Contrast

14. PET results
PET/CT
PET/MR

15. Reconstruction pipeline
ZTE MRI
Reconstruction pipeline
Denoising
Intensity normalization
LAVA-FLEX MRI
Head atlas
Non-rigid registration
Head mask extraction
Energy scaling
Bias correction
Atlas MRAC
Resampling
Partial volume mask extraction
Hardware attenuation templates
Template merging
Sinus mask extraction
Energy scaling
Complete attenuation map
In-vivo attenuation map
Bone mask extraction
Resampling
Cavity mask extraction
Hardware attenuation map
Merging
Density mapping
Complete attenuation map
Pseudo-CT

16. Qualitative results

17. Quantitative results

18. Quantitative results with normalization

19. Results with template-enhanced ZTE

20. Ongoing work: Reconstruction improvements

21. Ongoing work: Vascular imaging

22. Conclusion Clinically relevant, ideal indication for PET/MR.
Successful PET/CT+PET/MR study, pre- & post- therapy.
Marginal quantitation improvement with ZTE-AC.
Preliminary evaluation of more advanced methods.
Ongoing work to improve PET resolution.
Ongoing work to improve anatomical context for surgery.

23. Questions?