Inferior petrosal sinus sampling

Procedure

The procedure is typically performed in large medical centers by an experienced interventional radiologist, neurologist or neurosurgeon and guided using fluoroscopy. Catheters are inserted through the jugular or femoral veins into both inferior petrosal veins which drain blood from the pituitary gland. To maximize and stabilize the pulsatile ACTH secretion, a dose of intravenous corticotropin-releasing hormone (CRH) is usually given. ACTH levels are measured in the petrosal (central) and peripheral venous plasma before and within 10-12 minutes after administration of CRH. Where CRH is unavailable some centers use desmopressin. Measurement of the central-to-peripheral prolactin ratio can assist in verifying the correct placement of the catheters as well as in normalization of ACTH levels. In experienced centers, successful bilateral catheterization is reported in up to 90% of cases with very rare major complications.

Interpretation

In patients with true hypercortisolism, a central-to-peripheral ACTH gradient of ≥2 before, or ≥3 after CRH administration, is considered diagnostic for a pituitary source of ACTH. Some studies have shown that if catheters were appropriately placed, a gradient of ≥1.4 for ACTH concentrations between the two sinuses predicted the side of the tumor with ~70% accuracy.

References

References

1. (December 2021). "Consensus on diagnosis and management of Cushing's disease: a guideline update". The Lancet. Diabetes & Endocrinology.
2. (September 2007). "Desmopressin test during petrosal sinus sampling: a valuable tool to discriminate pituitary or ectopic ACTH-dependent Cushing's syndrome". European Journal of Endocrinology.
3. (February 1999). "A critical analysis of the value of simultaneous inferior petrosal sinus sampling in Cushing's disease and the occult ectopic adrenocorticotropin syndrome". The Journal of Clinical Endocrinology and Metabolism.
4. (August 2020). "Inferior petrosal sinus sampling – 16 years of experience from a single tertiary center in Israel". Bioscientifica.
5. (September 1991). "Petrosal sinus sampling with and without corticotropin-releasing hormone for the differential diagnosis of Cushing's syndrome". The New England Journal of Medicine.
6. (June 2013). "The lateralization accuracy of inferior petrosal sinus sampling in 501 patients with Cushing's disease". The Journal of Clinical Endocrinology and Metabolism.