Nonvisualization of the fetal gallbladder: frequency and prognostic importance.

PURPOSE: To assess the frequency of fetal gallbladder visualization through gestation and to determine the prognostic importance of nonvisualization. MATERIALS AND METHODS: Demonstration of the gallbladder was prospectively attempted in 578 consecutive second- and third-trimester obstetric ultrasound examinations. Data regarding gallbladder visualization were stratified into subgroups on the basis of estimated gestational age. Postnatal follow-up was performed in 80 fetuses with nonvisualization of the gallbladder. RESULTS: The gallbladder was seen on 477 of 578 (82.5%) fetal sonograms. The likelihood of gallbladder visualization increased with advancing gestational age, reaching a plateau of approximately 95% between 24 and 32 weeks. After 32 weeks, the frequency of visualization declined. Seventy-five of the 80 fetuses with nonvisualized gallbladders who underwent follow-up had normal outcomes. Except for one fetus with trisomy 21, all fetuses with abnormalities had relatively minor, non-life threatening problems that did not involve the gallbladder or biliary tract. CONCLUSION: Most fetuses with nonvisualization of the gallbladder have normal outcomes. The rate of nonvisualization of the fetal gallbladder is sufficiently high to undermine the utility of gallbladder visualization as a screen for fetal abnormality.

Urinary bladder diverticula: sonographic diagnosis and interpretive pitfalls.

Diverticula of the urinary bladder can occasionally appear as complex pelvic masses not obviously connected to the bladder. Such presentations can lead to diagnostic confusion and interpretative error. Sonographic findings and clinical histories were reviewed in 11 patients in whom bladder diverticula were initially mistaken for other types of pathologic pelvic processes. Sonographic techniques that were helpful in elucidating the true nature of the lesions included scanning from different perspectives with increasing increments of bladder distention, postvoid images, endovaginal views, and color Doppler interrogation. The diagnosis of bladder diverticula should be considered and actively pursued when sonologists are confronted with pelvic masses of ambiguous origin.

Chemical shift imaging of atherosclerosis at 7.0 Tesla.

Chemical shift imaging (CSI) was performed on cadaveric atherosclerotic fibrous plaques, periaortic adipose tissue, and cholesterol standards using a 7.0 Tesla horizontal bore prototype imaging spectrometer. Proton spectroscopy of intact tissue and deuterated chloroform extracted samples was done at the equivalent field strength of 7.0 Tesla on a vertical bore spectrometer, including studies of temperature dependence and T2 relaxation measurements. Spectra obtained using CSI on the imaging magnet were comparable with those from the conventional vertical spectrometer. Fibrous plaques and adipose tissue had unique spectral features, differing in the ratios of their water and various fat components. Chloroform extractions revealed a typical cholesteric ester spectrum for the fibrous plaque in contrast to the triglyceride spectrum of the adipose tissue. These two tissues also had different T2 relaxation measurements of their major fat resonances, with fibrous plaques having a short T2 compared to adipose tissue (15.9 milliseconds vs. 46.2 milliseconds). Temperature dependence studies showed that spectral signal intensity of the fat resonance of the fibrous plaque increased while linewidth decreased with increasing temperature from 24 degrees C to 37 degrees C. Atherosclerotic lesions may be studied at 7.0 Tesla, and NMR parameters defined in the present study may be used for further studies at other magnetic field strengths.