Fig. 23.12 
Conn's adenoma in the left adrenal gland: demonstrated by venography (with normal venogram for comparison). 
Film (a) shows the typical venographic appearance of a Conn's adenoma. The catheter tip is in the left adrenal vein and contrast medium has filled veins stretched around a I cm tumour in the superior pole of the adrenal gland. This appearance should be compared with that of a normal left adrenal venogram (b). Blood for aldosterone estimation should be taken from the adrenal vein prior to venography because of the risk of extravasation of contrast medium during that procedure. Even careful venography carries a small risk of adrenal infarction which could result in adrenal insufficiency if both adrenal glands are compromised. Adrenal venography alone is rarely carried out today, except to identify the catheter position during venous sampling.