The source of ACTH must be defined; the only way to do this is inferior petrosal
sinus ACTH after corticotropin-releasing hormone stimulus.
However, pituitary MRI was negative and inferior petrosal
sampling did not show a central to peripheral ACTH gradient.
Diagnostic errors aider inferior petrosal
1) Meningiomas can be confined to the IAC because the arachnoid villi can be distributed within the IAC and along the superficial petrosal
Bilateral inferior petrosal
sinus sampling seems to be the most accurate method for distinguishing pituitary from ectopic production of corticotrophin (1).
If a rapid ACTH test is used during the catheterization procedure, those patients with increased ACTH in the jugular venous samples do not need to undergo catheterization of the more proximal petrosal
veins, which is a more complex and risky procedure (73).
A loop of the superior cerebellar artery (SCA) and occasionally the anterior inferior cerebellar artery (AICA) or the petrosal
vein is identified as the vessel causing the compression.
5) The nerve then makes a sharp turn (genu) and enters the tympanic segment, giving off the greater, lesser, and external petrosal
Bilateral simultaneous inferior petrosal
sinus sampling (BIPSS) is a highly sensitive but invasive method used in the differential diagnosis of ACTH-dependent CS.
The following extracranial veins join the internal jugular vein in its passage through the neck; the inferior petrosal
sinus, pharyngeal plexus, facial vein, lingual vein, superior thyroid veins, middle thyroid vein, and jugular lymph trunk.
It is surrounded by various clinically significant structures, including the cochlea, middle ear, eustachian tube, gasserian ganglion, geniculate ganglion, greater superficial petrosal
nerve, and jugular fossa.
sinus sampling (IPSS) was performed only in one patient and confirmed the diagnosis of CD.