Recognition and management of Budd-Chiari syndrome: report of one hundred cases

Budd-Chiari syndrome is an unusual form of portal hypertension caused by occlusion of the hepatic venous outflow, and it is often confused with portal hypertension caused by liver cirrhosis. Its prognosis is poor, and optimal therapy remains to be established. This is a report of 100 confirmed cases of this syndrome treated from December 1982 to March 1988 at two vascular centers in China. Sixty-two male and 38 female patients, 15 to 62 years of age (mean age, 32.6 years) were treated. Seventy-six patients had intractable ascites, 56 had esophageal varices, and 22 had upper gastrointestinal bleeding. There were 37 cases of membranous obstruction, 57 cases of occlusion of the inferior vena cava above the confluence of the hepatic veins, and 6 cases of occlusion of the hepatic veins. Eighty-one patients were operated on. Operative mortality rate was 8.6% (7/81). Follow-up from 2 to 66 months revealed that 58 of the patients operated on (72%) had good results, whereas 11 of 19 (58%) patients treated nonoperatively died within 2 months after admission. On the basis of these data we conclude that the operative procedure must be tailored to the cause and underlying pathologic characteristics. Mesoatrial shunting is the operation of choice for patients with occlusion of the retrohepatic inferior vena cava and hepatic veins, and inferior vena cava--atrial shunting is the operation of choice for patients with occlusion of the inferior vena cava and patency of the hepatic veins. Membranotomy is used for patients with inferior vena cava webbing, and mesocaval shunting is used for patients with intrahepatic venous occlusion only.(ABSTRACT TRUNCATED AT 250 WORDS)

Seroepidemiologic study of rubella in selected Chinese female

To have a better understanding of rubella seroepidemiology among female population in Taiwan, we report a serologic survey of 4030 examinations for 2030 school girls and 2000 pregnant women, using enzyme-linked immunosorbent assay for the detection of rubella specific IgG. RA 27/3 vaccines were given to susceptible volunteer students and postpartum women for the evaluation of vaccine efficiency and its side effects. The results showed that the rubella susceptible female among 8 to 22-year-old girl students was 44.97%, which was higher than expected, as most of them experienced the outbreak of rubella in 1977. The susceptibility rate among the pregnant women was 19.35%, which was also higher than expected for an age group having been through two outbreaks in the past. All the vaccinees showed good tolerance to the vaccine and the seroconversion rate was 100%. With such high susceptibility rate among women of child bearing age and girl students, plus the endemic property of rubella infection in Taiwan, we can expect a high risk of congenital rubella syndrome. Mass vaccination against rubella should be brought into effect immediately.

Flow-induced phase effects and compensation technique for slice-selective pulses

Flowing spins experience a time-varying frequency during the application of slice-selective radiofrequency (RF) pulses. As a result the flowing spins accumulate phase relative to stationary spins as the spins are rotated toward the transverse plane. Using finite difference techniques to solve the Bloch equations for flowing spins, the phase of the transverse magnetization after a slice-selective pulse was evaluated for varying flow velocities and for tip angles which ranged between 0 degrees and 180 degrees. The following results were obtained for constant slice thickness: (1) For a fixed tip angle, the phase varies nonlinearly with velocity. (2) For a fixed velocity, the phase varies nonlinearly with tip angle. For small tip angles the nonlinearity in the variation as a function of velocity is very small but increases for tip angles greater than 90 degrees and becomes especially severe near 180 degrees. A method is proposed to desensitize the phase of flowing spins during the application of slice-selective pulses. The compensation scheme depends upon tip angle but is virtually independent of flow velocity. The technique was tested and verified with clinical images.

The solution of Bloch equations for flowing spins during a selective pulse using a finite difference method

The movement of spins during periods of selective pulses result in a modulation of the signal intensity and phase of the received magnetic resonance imaging (MRI) signal, and is a major cause of signal loss from vessels imaged with slice-selective pulses. Methods are well developed for compensation of phase perturbations for spins flowing at constant velocity during the time of applied gradients. However, for spins flowing during selective pulses, the magnitude of the amplitude and phase perturbations has not been understood nor to this time has any method of flow compensation been proposed. This is due in part to the difficulty in using the Bloch equations to quantify the amplitude and phase modulation during radiofrequency (rf) excitation since solutions cannot be obtained analytically. In this paper a finite difference method is used to solve Bloch equations for flowing spins during a 90 degrees selective pulse. Compared with stationary spins, the magnetization distribution for flowing spins exhibits a shift of the slice profile in the direction of the flow, an expansion of the profile, phase shifts, and changes in profile shape. The profiles show residual phase errors which become more severe with higher flow velocities, with flow compensation schemes which apply in the case of spins flowing during applied gradients, and in the absence of an rf pulse. The measurement and understanding of the magnetization distribution is important to designing pulse sequences that compensate for flow. Flow compensated pulse sequences are necessary to reduce image flow artifacts and to increase signal of vessels in MR angiographic images.