Inferior petrosal sinus sampling

Case contributed by Assoc Prof Frank Gaillard


ACTH dependent Cushing's syndrome and congestive cardiac failure. CT of the chest, abdomen and pelvis demonstrates no focal abnormality.

Patient Data

Age: 70 years
Gender: Female

MRI pituitary

Two 3 millimeter areas of delayed enhancement are seen in the pituitary gland, one on the right just posterior to the level of the stalk and the other more centrally at the same level. Whether both of these are functional microadenomas or whether one is non secretory is uncertain.  Pituitary stalk is midline. Chiasm and cavernous sinuses are uninvolved, with normal cavernous carotid flow voids.

Annotated image

Annotated images

Two possible microadenomas. One seen best on dynamic imaging (red arrow) is the more likely one. On delayed coronals another apparent region of hypo-enhancement (blue arrow) is seen, however as it neither seen on dynamic or sagittal imaging it is unlikely to be real. 

DSA (angiography)

Inferior petrosal sinus sampling

Bilateral groin punctures were performed and 5 french 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 placed equidistant from the pituitary fossa, their position confirmed with further injections of contrast. 
The last 2 images are of lateral and frontal projections demonstrating the final position of the microcatheters in the left and right petrosal sinuses.

Following this simultaneous sampling of each microcatheter and the peripheral venous blood (via the groin sheath) was performed pre and post administration of CRH. 

Annotated image

Annotated images

The images are of:

  • frontal projection of injection into the left jugular demonstrating retrograde flow up the left IPS and across to the right IPS. Retrograde flow up the sigmoid and transverse sinus and across to the right side is also noted. 
  • lateral projection of the same run as the first image.
  • final positioning of microcatheters.

The venous ACTH levels obtained from the right and left petrosal sinuses and peripheral blood are as follows (00:00 = baseline, other times are in minutes post CRH administration):

  • 00:00 right perosal sinus            14.7
  • 00:02 right perosal sinus             243
  • 00:05 right perosal sinus             139
  • 00:10 right perosal sinus            93.0
  • 00:15 rigth perosal sinus            58.4
  • 00:00 left perosal sinus             8.06
  • 00:02 left perosal sinus             81.7
  • 00:05 left perosal sinus             81.3
  • 00:10 left perosal sinus             11.5
  • 00:15 left perosal sinus             8.50
  • 00:00 peripheral                     1.40
  • 00:02 peripheral                     1.51
  • 00:05 peripheral                     1.43
  • 00:10 peripheral                     2.53
  • 00:15 peripheral                     3.29

These results are consistent with a pituitary microadenoma, most likely in the right side of the gland. 

Case Discussion

On the basis of the IPSS and MRI this patient went on to have an exploratory transphenoidal hypophysectomy. Although histological proof of a microadenoma was not achieved, the patient became biochemically normal following surgery and their ACTH levels returned to normal. 

At 18 months follow up remains well with normal pituitary function. 

Case courtesy of A/Prof Peter Mitchell, Royal Melbourne Hospital

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Case information

rID: 17876
Published: 21st May 2012
Last edited: 6th Jun 2021
Inclusion in quiz mode: Included