Petrosal Venous Sinus Sampling

Fig. 1

A detailed knowledge of normal and variant pituitary venous drainage anatomy. DSA venogram with catheter tips bilaterally in the inferior petrosal sinuses (black arrowhead). Internal jugular vein (blue arrowhead) and cavernous sinus (white arrowhead)

Aberrant

There is considerable variation in both the anatomical positions of the junctions between each venous segment and their morphology. A variety of classifications of IPS anatomy have been proposed. Procedurally the key factors determining accurate catheter positioning are the position of the junction of the IPS into the internal jugular vein, its morphology (plexus or single vein), and the presence and position of the anterior condylar vein. Three basic patterns of venous anatomy (Types A–C) have been described, all with separate variants (Fig. 2).

Fig. 2

Anatomical variants of the inferior petrosal sinus (IPS). Type A – venous drainage into the internal jugular vein is via a single inferior petrosal sinus (anterior condylar vein may or may not be in communication). Type B – drainage via a plexus of smaller vessels. Type C – IPS drains into the vertebral venous plexus via the anterior condylar vein

The pattern of venous drainage differs between the two sides in up to 40 % of patients necessitating pre-sampling venous angiography. For example, in Type C anatomy, IPS sampling would lead to false-negative results as pituitary venous drainage is via the vertebral venous plexus.

Equipment

Catheters: MPA and microcatheter

Pre-procedure Medications

Performed either under conscious sedation or without sedation or systemic analgesia.
Pediatric BIPSS may require general anesthesia.

Procedure

Access

Review any relevant previous pre-procedural imaging.

Femoral venous access.
Two 6 or 7-French sheaths in the femoral vein. These can be unilateral, but in children/smaller veins a bilateral technique used.
The sheaths should be oversized by 1 French relative to the catheter used to allow peripheral venous sampling.