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Published on: January 17, 2018
Ectopic posterior pituitary high signal in preoperative and postoperative macroadenomas: dynamic MR imaging
Takahiro Takahashi1, Yukio Miki, Jun A Takahashi
1Department of Nuclear Medicine and Diagnostic Imaging, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
Background And Purpose:
In patients with macroadenoma, posterior pituitary high signal (PPHS) on T1-weighted magnetic resonance (MR) imaging is sometimes observed in an ectopic location. The present study compared incidences of ectopic PPHS before and after macroadenoma surgery using MR imaging, including dynamic MR imaging to ascertain whether this ectopic change is irreversible.
Materials And Methods:
MR imaging was performed preoperatively in 111 cases of macroadenoma, and then repeated more than 1-year postoperatively in 47 patients. Enhancement of PPHS was assessed using dynamic MR imaging. Areas of enhanced hyperintensity were considered true PPHS, and the relationship between presence and location of true PPHS and adenoma volume was analyzed. Moreover, changes in the presence and location of true PPHS were ascertained among the patients who underwent postoperative follow-up MR imaging.
Results:
Preoperatively, PPHS was seen only in the normal location in 29 patients (Group A: 26.1%). High signal was detected only in an ectopic location in 58 patients, and early enhancement of this ectopic high signal was confirmed by dynamic MR imaging in 56 patients (Group B: 50.5%). No PPHS was observed in 24 patients (Group C: 21.6%). Adenoma volume was significantly greater for Group B than for Group A (p<0.001). Among the Group B patients who underwent MR imaging postoperatively (n=31), the location of PPHS was not changed, except for two patients in whom PPHS was absent. Postoperatively, PPHS was not observed in the normal location in any patient in the Group B.
Conclusions:
Greater volume of adenoma is associated with a higher incidence of ectopic PPHS, and the ectopic change is irreversible.
Insights
Ectopic posterior pituitary high signal (PPHS) on MRI is linked to larger pituitary adenomas and appears to be an irreversible change. This finding is crucial for understanding pituitary adenoma effects.
Area of Science:
- Radiology
- Neuroimaging
- Endocrinology
Background:
- Posterior pituitary high signal (PPHS) on T1-weighted MRI can appear in ectopic locations in patients with pituitary macroadenoma.
- The nature and permanence of this ectopic PPHS are not fully understood.
Purpose of the Study:
- To compare the incidence of ectopic PPHS before and after macroadenoma surgery.
- To determine if the ectopic PPHS change is irreversible using dynamic MR imaging.
Main Methods:
- 111 patients with macroadenoma underwent preoperative MR imaging.
- 47 patients had follow-up MR imaging more than 1 year postoperatively.
- Dynamic MR imaging assessed PPHS enhancement to confirm true PPHS and analyze its location relative to adenoma volume.
Main Results:
- Preoperatively, 50.5% of patients showed ectopic PPHS, significantly associated with larger adenoma volumes compared to normal PPHS.
- Postoperative follow-up in 31 patients revealed persistent ectopic PPHS in most, with no return to the normal location.
- Two patients experienced PPHS absence postoperatively, but the ectopic location was generally irreversible.
Conclusions:
- Increased pituitary macroadenoma volume is associated with a higher likelihood of ectopic PPHS.
- The observed ectopic PPHS in macroadenoma patients is largely irreversible.
