[Viability of human cancer cells in culture after exposure to diagnostic ultrasound]

Reports have appeared in the literature regarding biological damage to human cells following exposure to diagnostic ultrasound. We have examined the effects of diagnostic ultrasound (Sonel 400, C.G.R.) on human cell lines established in our laboratory. We report here that exposure to diagnostic ultrasound, at maximum exposure intensity and at exposure time as long as 60 minutes, produces no cell lysis as determined by vital dye exclusion ability, and as confirmed by electron microscopy. However, the exposure to ultrasound produced by an apparatus delivering an acoustic power higher than the diagnostic levels (Sonoscope-Alcatel) can cause the complete lysis of the same cells.

[Experimental studies on possible biological effects of ultrasonic diagnosis: ultrastructural analysis of rat embryo]

Within the limits of a systematic research on the biological effects of the ultrasounds, the authors refer on their personal experience on rat's embrions treated, for 120 seconds, with a ultrasonic beam having the common characteristics used in diagnostic investigations. The ultra-structural studies on the hepatic parenchyma substantially confirm the previous results obtained in the adult cavy, exposed for the same period of time, i.e. a diffuse cytoplasmic vacuolization and an unstable mitochondrial damage. Various suggestions are advanced on the particular sensibility that the mitocondria show because of the ultrasonic action. The authors explain the limits of their experimentation in this specific sector of the scientific research.

Auditory evoked potential alterations induced by pulsed ultrasound

Diagnostic levels of pulsed ultrasound were applied abdominally over the uteri of pregnant rats for five minutes daily during the first 20 days of gestation. The average energy output of the ultrasound machine at the optimum focal length of the transducer (5.4 cm) was 7.2 mW/sq cm. Postnatal auditory evoked potentials demonstrated a significant alteration in the offspring of the treated animals when compared with similarly treated, but nonexposed controls. This alteration only occurred in the high frequency range. Neither light nor electron microscopy revealed significant morphologic alterations in the cochlear elements of the exposed offspring. Although a cochlear deficit occurred in a range known to be important to the rat's hearing, several issues make this data reassuring to clinicians using diagnostic levels of pulsed ultrasound: the total amount of ultrasound exposure was higher than would be expected with human use, the defect was mild, and the absence of clear-cut morphologic abnormalities may indicate the presence of a minimal, or even reversible, defect.

Diagnostic ultrasound and sister chromatid exchanges: failure to reproduce positive findings

Human lymphocytes were exposed in vitro to ultrasound from two clinical devices, one of which was previously reported to have increased the frequency of sister chromatid exchanges. The ultrasonic exposures had no significant effect on the frequency of sister chromatid exchanges from three blood donors. Exposure to ultrasound also had no effect on cell cycle progression. A concomitant positive control (mitomycin C) resulted in a significant increase in sister chromatid exchanges.

Acute water intoxication following pelvic ultrasound examination

Ultrasonography is a widely used imaging technique whose popularity is based, in part, on its reputation for being relatively without risk to the patient. Like most procedures, however, ultrasound studies may be associated with complications, as the case presented here illustrates. A 79-year-old woman was given a large oral water load before a pelvic ultrasound examination and experienced symptoms of acute water intoxication afterward. When hyponatremia was corrected, the patient's condition returned to normal.

Legal liability in the use of ultrasound by office-based obstetricians

Ultrasound has proved to be a valuable diagnostic tool in the practice of obstetrics. Its rapidly increasing use by the office-based obstetrician, however, has opened a potential new area of legal vulnerability. The malpractice liability that may arise from its use is reviewed and practical ways to avoid it are considered.

Obstetric ultrasound and childhood malignancies

The mothers of 1731 children who died of cancer in the United Kingdom between 1972 and 1981, together with the mothers of 1731 matched controls, were asked about exposure to diagnostic ultrasound during the relevant pregnancy. The claims of 103 case mothers and 103 control mothers were verified by hospital records. Exposure to ultrasound in utero did not differ between cancer and control children. It is concluded that ultrasound is safe as regards the risk of cancer and leukaemia. The observed difference between cases and controls exposed during the earlier years of ultrasound use may be due to the selective application of this technique to abnormal pregnancies at that time.

Ultrasound examinations in pregnancy and childhood cancer

Analysis of information obtained in an inter-regional epidemiological study by interviewing the parents of 555 children with malignancy diagnosed between 1980 to 1983 and the parents of 1110 control children did not reveal any significant association between exposure to ultrasound examination in pregnancy and risk of childhood cancer.