Brian S. Garra, MD

The estimation of tissue hardness and masses by palpation during a physical examination is one of the oldest methods used in medical diagnosis. Palpation was practiced by Egyptian physicians as early as 2600 BCE.

Although ultrasound use in medicine continues to grow, the modality faces increasingly stiff competition from other modalities such as CT, MRI, and PET, which have undergone startling advances in the past several years. To respond to this competition, radiologists can employ several rapidly developing new technologies to enhance ultrasound's capabilities. With speckle reduction, volumetric imaging, and elastography, sonographers can reduce artifacts, improve image contrast, reduce image noise, and better gauge tissue stiffness to detect subtle hard-to-spot abnormalities. Proper use of these powerful new technologies can boost accuracy, repeatability, and efficiency to help keep ultrasound competitive with the other cross-sectional imaging modalities and perhaps open up new applications.

Diagnostic ultrasound is fading as a primary imaging modality in U.S. radiology departments. It is gradually being supplanted by CT, MR, and PET, which have seen major advances in speed and quality in the past decade. Multislice CT acquisitions allow whole-body scanning in minutes. Higher field MR scanners with more advanced pulse sequences and better coils have not only speeded up MR imaging but have vastly improved its ability to image blood vessels and blood flow without contrast toxicity and radiation exposure. PET/CT's ability to image metabolically active tissues at high spatial resolution has made it the modality of choice for cancer evaluation.