Clinical utility of spoiled-gradient echo 3D-T1 sequence in deciding appropriate treatment strategy for ACTH-producing pituitary adenoma; a case report and review of the literature

INTRODUCTION AND IMPORTANCE: When treating adrenocorticotropic hormone (ACTH)-producing adenoma, accurate tumor localization is critical. We report a case of Cushing's disease in which MRI with a spoiled-gradient echo 3D T1-weighted sequence was useful in precise localization of an ACTH-producing adenoma and deciding appropriate treatment strategy. CASE PRESENTATION: A 47-year-old woman was admitted to our hospital with signs and symptoms of Cushing's disease. Laboratory findings showed hypercortisolemia and suggested Cushing's disease. However, neuroimaging on conventional pituitary MRI using a spin-echo (SE) protocol did not confirm pituitary adenoma in the sella turcica. Inferior petrosal sinus sampling suggested a higher central/peripheral ratio of ACTH after corticotropin-releasing hormone (CRH) administration on the right side. Reviewing the dynamic MRI using an SE protocol from that perspective, we vaguely identified a 5.0 mm area of gradual contrast on the right side of the pituitary gland. In addition, pituitary MRI with a spoiled-gradient echo 3D T1-weighted sequence, a 2.0 mm hypo-enhancing region was identified on the right side within the anterior pituitary gland. The tumor was resected completely removing the right pituitary gland including the tumor. The histological diagnosis was ACTH-producing pituitary adenoma. Symptoms of Cushing's disease gradually improved and endocrinological function normalized. Follow-up neuroimaging after 1 year showed no signs of recurrence. CLINICAL DISCUSSION: In the treatment of Cushing's disease, accurate detection of ACTH-producing pituitary adenoma is crucial to maximizing curative rates. However, exact confirmation of the tumor location is very difficult. CONCLUSION: MRI with a spoiled-gradient echo 3D T1-weighted sequence may facilitate accurate tumor localization and appropriate treatment strategy.