Evaluation of desmopressin stimulated bilateral inferior petrosal sinus sampling in diagnosing Cushing′s disease

Objective To evaluate desmopressin stimulated inferior petrosal sinus sampling in diagnosing Cushing′s disease.Methods Sixteen ACTH-dependent Cushing′s disease patients underwent bilateral desmopressin stimulated inferior petrosal sinus ( IPS ) sampling because of negative or equivocal magnetic resonance imaging.Cortisol response to high-dose dexamethasone suppression test was also evaluated.ACTH sampling was taken from a peripheral vein and bilateral IPS before and both 5 and 10 min after injection of desmopressin.Diagnosis was based on the ratio of ACTH level in between IPS to peripheral vein by desmopressin test.Diagnosis was confirmed after surgery.Results High-dose dexamethasone suppression test showed suppressible in 9 of 16 patients with Cushing′s disease.An IPS gradient ＞2 was found in 14 of the 16 cases (87.5％ )with Cushing′s disease after desmopressin injection,while before injection the respective figure was 12 of 16 (75.0％).No severe adverse effects were observed during or after the procedure.Conclusion Desmopressin test during bilateral IPS sampling is a safe and effective diagnostic procedure in Cushing′s disease. Key words: Cushing′s disease;  Bilateral inferior petrosal sinus sampling;  Desmopressin;  Diagnosis