Agenda

Better living through pharmacology

By James Brice

Diagnostic pharmacology is heading toward a renaissance that will make the dreams of every contrast agent salesperson come true. Most radiological procedures will eventually be performed with a contrast agent designed to track therapies on a cellular level.

Contrast enhancement has been available practically since radiology's genesis. Early radiologists learned that a drop of iodine could work magic diagnostically but could also cause adverse reactions. The iodinated contrast agents' Jekyll and Hyde character formed the basis of radiology's love-hate relationship with contrast media.

Exquisite anatomical images without the use of contrast agents have long been a component of the idealized, perfect radiological examination. Eliminating contrast would go a long way to reducing patient discomfort, and subtracting the variable cost of the agents would make imaging less expensive.

Several modalities developed in the latter part of the 20th century came close to that goal. Purists thought they had found the perfect exam in MRI, until the developers of gadolinium-DTPA demonstrated that contrast-enhanced MRI is better in many instances. Ultrasound is still performed without contrast, but that will change for some applications when several agents break through the FDA logjam.

No matter how laudable it may be, the dream of totally noninvasive radiology will be dashed when molecular imaging is ready for clinical prime time. Molecular imaging will resemble nuclear medicine but on a much broader scale. Many early applications of mo-lecular imaging will, in fact, use radionuclides to track cells and report gene expression.

This is an inevitability that radiologists will have to accept. Better living is destined to come to radiology through chemistry.