Diagnostic Ultrasound in Obstetrics

I. INTRODUCTION

Since the 1950’s, ultrasound has been a common diagnostic tool used in obstetric medicine. For quite some time, human epidemiological studies have concluded that there are no deleterious effects associated with ultrasound screening in any stage of a woman’s pregnancy [1]. In addition, there has been no official ruling by any medical association that contraindicates this practice [2], [3] and at the same time, no governing protocol or directive that polices their use. Despite the lack of significant correlation, there have been some observable differences in neonates that are statistically ignored [4], [5]. Although considered as not-significant, such data coupled with limited understanding, is evidence enough to proceed with caution when using ultrasound.

The widespread acceptance of ultrasound is based on a lack of evidence, rather than a concrete understanding of the physiological changes involved with bioheat transfer and imaging. This then suggests that there are no risks involved to the patient under such a procedure. Closer scrutiny should be applied to this area of medicine, in light of the fact that x-rays were once deemed to be safe during pregnancy, but later found to cause neural mutation and death in fetuses [6].

II. REVIEW OF ULTRASOUND

History

From Doppler’s first published observations in 1842 that led to his namesake, the Doppler effect, it was not immediately evident, the role ultrasound would play in medicine. It would still be another 50 years from the time the Curie brothers realized the piezoelectric effect, that diagnostic ultrasound would be suggested.

Through different iterations, the acoustic waves known as ultrasound would first manifest its practical properties in the marine world and be used for such things as iceberg and submarine detection. Initially used for its heating properties as a therapeutic tool in the early 1930’s [6], [7], it was proposed, in the late 1940’s, that the non-invasive technique could be harnessed for focal tissue burning. This was applied to the field of ultrasound surgery and was crucial in treating the symptoms of Menière’s disease by destroying vestibular function [6].

In 1937, Karl Dussik first suggested the use of ultrasound for diagnostic purposes. He proposed a method for sending ultrasonic waves to the skull to display a “hyperphonogram.” The onset of World War II halted any progress in this area in medicine, but the war allowed special focus on the progress of ultrasound in enemy detection. A decade later, John Julian Wild published his thoughts on “The use of ultrasonic pulses or the measurement of biological tissues and the detection of tissue density changes.” Shortly after, ultrasound studies began steamrolling the field. Visualization of soft tissue structures via ultrasound led to the detection of flaws in