Low-osmolar CT contrast is safe for patients with pheochromocytoma
Intravenous low-osmolar contrast–enhanced CT can safely be used in patients with pheochromocytoma who are not receiving a- or ?-blockers, according to a prospective study in the Jan. 6 issue of the Annals of Internal Medicine.

Contrast-enhanced CT is useful for localizing pheochromocytoma. However, the authors noted that in patients with suspected pheochromocytoma, CT is often canceled or not performed because of “the strong belief” that intravenous contrast may induce hypertensive crisis.

Smita K. Baid, MD, from the Warren G. Magnuson Clinical Center, National Institutes of Health (NIH) in Bethesda, Md., sought to examine whether intravenous low-osmolar contrast administration during CT induces catecholamine release that increases blood pressure or heart rate.

The researchers studied 22 patients with pheochromocytoma (15 nonadrenal; seven adrenal) and eight unmatched control participants without pheochromocytoma.

Baid and colleagues found that plasma catecholamine levels within and between groups did not significantly differ before and after intravenous administration of low-osmolar CT contrast. They reported that patients with pheochromocytoma experienced a clinically and statistically significant increase in diastolic blood pressure that was not accompanied by corresponding increases in plasma catecholamine levels.

The difference became non–statistically significant after adjustment for use of a- and ?-blockers, the authors wrote.

According to the researchers, the study had limited statistical power to detect differences between case patients and control participants.

However, Baid and colleagues concluded that contemporary low-osmolar CT contrast is safe for patients with pheochromocytoma based on their findings.

Eunice Kennedy Shriver National Institute of Child Health and Development and the NIH funded the study.