Journal of Diagnostic Medical Sonography

To correlate potential bioeffects with exposure to ultrasound, a quantitative characterization of the ultrasound beam is essential. As a first step in this process various intensity descriptors have been developed. These intensity descriptors are defined and compared. The intensity ranges of different types of diagnostic instruments are presented.

Damage induced by ultrasound is associated with mechanical, thermal, and cavitation interactions with matter. The physical basis for each is discussed. Cavitation is examined in detail with the aid of illustrative examples.

Color Doppler was used to evaluate urine jets within the urinary bladder in adult patients. In normally hydrated patients, urine was noted to jet from both sides within an interval of a few seconds. Future use of color Doppler in evaluating renal function and urinary tract pathology by visualizing urine output may be possible.

With the advent of advanced duplex ultrasound or color flow Doppler, the authors believe that a complete assessment of aneurysm can be obtained by ultrasound alone. The information required by the surgeon for surgical resection of various types of aneurysms is outlined. The ability of color flow Doppler to rapidly assess both the arterial wall and residual lumen, identify stenoses and branches, in addition to simplifying complex flow phenomenon make it uniquely qualified for this task. To date, the authors have completed eight aortic grafts based solely on the ultrasound findings.

The genitalia was visualized as a part of the general fetal anatomical survey during prenatal ultrasound of more than 2210 fetuses between the ages of 16 to 42 weeks. The sex detection rate for 1200 male fetuses was more than 93%. No testicular descent was present before 20 weeks but was seen as early as 22 weeks; 98% of fetuses showed descent of one or both testes at about 35 weeks. Moderate hydrocele was detected in 5% of fetuses of 30 weeks gestation or older. No abnormality was found in a patient with bilateral neonatal testicular torsion during prenatal ultrasound. The authors believe a brief examination of fetal genitalia may identify abnormalities of fetal gender and detect more serious conditions such as scrotal hernia and prenatal testicular torsion, which requires surgical intervention at birth.

The climate that has developed from the shortage of imaging professionals has placed increased burdens on clinical instructors. Thus, educational programs must ensure that students continue to receive appropriate clinical education. One simple technique that has been successful in ensuring appropriate clinical education at the institution of the authors is discussed.