Advances in imaging.

The introduction of sonography, x-ray computed tomography, magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS) have enhanced the radiologist's ability to delineate and stage neoplasms in all parts of the human body. Images of excellent quality can be generated within a reasonable time frame and with minimal biologic risk. All of the more sophisticated imaging modalities are costly and none can, isolated from clinical data, provide histologic diagnoses. Within the next few years it is anticipated that the speed of magnetic resonance image acquisition will increase and that contrast agents for MRI will be brought into clinical use. Evaluation of cost-effectiveness will continue and new diagnostic algorithms can be expected to evolve.