Localization of insulinomas to regions of the pancreas by intra-arterial stimulation with calcium.
OBJECTIVE
To determine the sensitivity of calcium injected into pancreatic arteries in localizing insulin-secreting tumors to regions of the pancreas.


METHODS
To stimulate the release of insulin, 25 patients with surgically proven insulinomas (average diameter, 15 mm) had calcium gluconate (0.025 mEq Ca++/kg body weight) injected before surgery into the arteries supplying the pancreatic head (gastroduodenal and superior mesenteric arteries) and the body and tail (splenic artery) of the pancreas.


METHODS
Tertiary referral hospital.


METHODS
Insulin levels were measured in samples taken from the right and left hepatic veins before and 30, 60, and 120 seconds after calcium injection. A twofold increase in insulin level in the sample taken from the right hepatic vein 30 or 60 seconds after injection localized the insulinoma to the segment of the pancreas supplied by the selectively injected artery. Localization done using calcium stimulation was compared with localization done using transcutaneous ultrasonography (n = 22), computed tomography (n = 23), magnetic resonance imaging (n = 21), arteriography (n = 25), and portal venous sampling (n = 9).


RESULTS
Calcium stimulation localized 22 of 25 insulinomas (sensitivity, 88% [95% CI, 68% to 97%]) to the correct region of the pancreas. The sensitivities of the other imaging methods were 9% for ultrasonography (CI, 1% to 23%), 17% for computed tomography (CI, 5% to 39%), 43% for magnetic resonance imaging (CI, 22% to 66%), 36% for arteriography (CI, 18% to 57%), and 67% for portal venous sampling (CI, 30% to 93%). Calcium stimulation added only a few minutes to the time needed for pancreatic arteriography and caused no morbid conditions.


CONCLUSIONS
Intra-arterial calcium stimulation with right hepatic vein sampling for insulin gradients is the most sensitive preoperative test for localizing insulinomas.
Doppman
J L
JL
Diagnostic Radiology Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892-1182, USA.
Chang
R
R
Fraker
D L
DL
Norton
J A
JA
Alexander
H R
HR
Miller
D L
DL
Collier
E
E
Skarulis
M C
MC
Gorden
P
P
D000328:Adult; D000368:Aged; D002125:Calcium Gluconate / Q000008:administration & dosage; D005260:Female; D006503:Hepatic Veins; D006801:Humans; D007269:Injections, Intra-Arterial; D007328:Insulin / Q000097:blood / Q000378:metabolism; D000078790:Insulin Secretion; D007340:Insulinoma / Q000175:diagnosis* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D012680:Sensitivity and Specificity
D007328:Insulin; D002125:Calcium Gluconate