7T MRI and Intraoperative Ultrasound-Guided Endoscopic Endonasal Resection of 3T MRI-Negative Pituitary Corticotroph Microadenoma: 2-Dimensional Operative Video

Pituitary microadenomas may be challenging to identify on MRI, precluding focal resection in some cases and increasing the risk of surgery.^1-4 Corticotroph adenomas in particular present as MRI-negative in up to 40% of cases.^4,5 Seven-tesla (7-T) MRI offers a greater level of detail than 1.5-T and 3-T and may be used to identify smaller pituitary lesions.^6,7 Intraoperative ultrasound may offer real-time image guidance.^8,9 In this video, the authors demonstrate a case of Cushing disease that was considered MRI-negative on 3-T imaging where 7-T MRI and intraoperative ultrasound supported the diagnosis and surgical management. The patient was a 60-year-old woman who presented with signs and symptoms typical of Cushing syndrome including weight gain, fatigue, and headache as well as refractory hypertension, and prediabetes. Preoperative laboratory workup was suggestive of Cushing disease; however, the patient was identified as MR-negative based on 3-T imaging. 7-T MRI showed a small region of hypoenhancement in the anterior-inferior pituitary gland suggestive of pituitary microadenoma. The patient provided consent and underwent endoscopic endonasal resection of the pituitary lesion with intraoperative ultrasound guidance. The surgery was uncomplicated, and histopathology confirmed a corticotroph adenoma. At 3-month follow-up, the patient had significant improvement in her symptoms, and laboratory studies supported biochemical cure. In this case, the combination of 7-T MRI and intraoperative ultrasound guided the endoscopic endonasal resection of a pituitary microadenoma, thereby minimizing the destruction of the healthy gland and ensuring the best outcome for the patient. Written informed consent was obtained from the patient for the publication of this work.