Once micro-catheters are in position, what is then done?
Simultaneous sampling of each microcatheter and the peripheral venous blood (via the groin sheath) is performed pre- and post-administration of corticotropin releasing hormone (CRH).
Explain the theory behind this test and how you interpret results.
CRH results in sudden release of ACTH from the ACTH-producing pituitary adenoma (if present), resulting in a rapid increase in the amount of ACTH in the blood draining from the pituitary. Typical values supporting the presence of a microadenoma are a high baseline ratio (pre-CRH > 1.7 : 1 central : peripheral) or a large local increase following stimulation (post-CRH > 3.3 : 1 central : peripheral).
Bilateral groin punctures were performed and 5 french guiding catheters passed up the IVC, through the right atrium and SVC into the internal jugulars to the base of skull.
Injection of contrast retrogradely opacified the inferior petrosal sinuses which were entered with micro-catheters (right, left) placed equidistant from the pituitary fossa, their position was confirmed with further injections of contrast. Contrast also outlines the sigmoid sinus and transverse sinus.
Following this simultaneous sampling of each microcatheter and the peripheral venous blood (via the groin sheath) was performed pre and post-administration of corticotropin-releasing hormone (CRH).