Endocrine Abstracts

Introduction: Up to 40% of cases with endocrinologically and surgically proven Cushing’s disease (CD) are MRI-negative¹. With intraoperative transsphenoidal ultrasound 72% of microadenomas in CD were identified as hyperechogenic structure². We report on the first 9 cases with intraoperative use of direct contact high-frequency ultrasound (hf-us) in patients with CD.

Patients: All 9 cases (all female, age 31–71 years) revealed typical symptoms of CD, 2 were recurrencies.

Technique: During direct transnasal microsurgical operations the sellar compartment was investigated in axial and sagittal direction at 12 and 13 MHz through the pituitary capsule after drilling of the bony floor by use of a digital ultrasound probe (B-mode frequency 7.5–13 MHz, wide of field 5 mm, penetration 20 mm).

Results: In all 4 cases with negative preoperative MRI intraoperative hf-us correctly localized micoadenomas. In 2 out of 5 cases with positive MRI hf-us identified a hyperechogenic structure at the site expected (positive control). In 2 other cases with micoadenomas MRI correctly predicted the site of the tumor, but no identification was possible by hf-us. In the only case with a macroadenoma, identification of the border between tumor and anterior pituitary gland was not possible by use of hf-us. Out of 8 cases with microadenomas, in 6 the tumor was identified by hf-us (75%). Early postoperative decline of serum cortisol to subnormal levels on the first postoperative morning revealed surgically induced remission of hypercortisolism in all 9 cases¹.

Conclusion: Intraoperative, direct contact hf-us may enable the surgeon to identify small pituitary adenomas even in cases of negative preoperative MRI, thus preventing these patients from extensive pituitary exploration.

1. Knappe UJ & Lüdecke DK. Neurosurgery 39 1996 484–493.

2. Ram Z et al. JNS 83 1995 225–230.