Petrous Sinus Sampling
Inferior Petrosal Sinus Sampling (IPSS) is an advanced minimally invasive diagnostic procedure used to identify the source of excess ACTH hormone in patients with suspected Cushing disease. It helps doctors distinguish whether ACTH is coming from a tiny pituitary adenoma or from an ectopic source elsewhere in the body. This is especially useful when MRI findings are unclear or the pituitary tumor is too small to detect.
During the procedure, thin microcatheters are gently guided through the veins, usually from the groin, to both inferior petrosal sinuses near the pituitary gland. Blood samples are taken before and after hormone stimulation, such as CRH or desmopressin, to compare ACTH levels. Modern biplane angiography, high-resolution venous mapping, roadmap imaging, and careful catheter navigation improve precision and safety. IPSS is not a treatment itself, but it plays a key role in planning the right treatment strategy.
Treatment / Procedure Approach
Petrosal Sinus Sampling is performed in a cath lab under image guidance. The doctor places small catheters into veins draining the pituitary gland and collects timed blood samples. The results help decide whether the patient may need pituitary surgery, further endocrine evaluation, or treatment for an ectopic ACTH source. IPSS is considered highly accurate for differentiating pituitary Cushing disease from ectopic ACTH secretion when done in the right clinical setting.
FAQs
No. It is a minimally invasive diagnostic procedure done through a small vein puncture.
Sometimes pituitary tumors are very small and may not be clearly visible on MRI. IPSS helps confirm the hormone source.
Most patients feel only mild discomfort. The procedure is usually done with local anesthesia and monitoring.
No. It helps doctors choose the correct treatment plan, such as pituitary surgery or further evaluation.
IPSS is generally safe in experienced hands, though rare complications can occur, so careful planning and monitoring are important.