Duplex Doppler ultrasound for the detection of vascular occlusion following liver transplantation in children.

Sixty-three children and adolescent patients who received 78 consecutive orthotopic liver transplants and had serial duplex ultrasound monitoring were retrospectively reviewed for episodes of occlusion of the hepatic artery or portal vein. There were 13 documented episodes of complete occlusion of the main hepatic artery or a major branch, of which nine were diagnosed by the absence of flow during duplex ultrasound examination. Four occlusions were not detected, two affected hepatic artery branches, one an accessory hepatic artery, and one the main hepatic artery. The overall sensitivity of the method was 69% and specificity 100%. Six portal vein occlusions were documented in five patients and all six were successfully diagnosed on ultrasound examination, giving a sensitivity and specificity of 100%. Three of the patients had simultaneous occlusions of both vessels. In the early post-operative period duplex Doppler ultrasound examination has proved an effective non-invasive method for the detection of vascular occlusion, but is not yet sensitive enough to replace angiography fully for the detection of hepatic artery occlusion, particularly when this occurs distal to the main hepatic artery.

Doppler ultrasound of the hepatic veins: normal appearances.

Doppler ultrasound of the hepatic veins gives a pulsatile velocity profile which mirrors the cardiac cycle. We describe the physiological basis for the complex waveform and suggest a venous pulsatility index (VPI) which can be used to quantify it. We have studied normal volunteers under differing conditions to establish a normal range of VPI. This provides a baseline against which abnormal patterns of hepatic vein Doppler can be judged.

The role of hepatic vein Doppler in diagnosing acute rejection following paediatric liver transplantation.

Serial Doppler ultrasound examinations of the hepatic veins were performed on 50 consecutive paediatric liver transplants. Damping of the normally pulsatile signal was observed in 23 of the 32 biopsy-proven episodes of rejection. In 10 episodes, the reduction in hepatic vein pulsatility preceded clinical and biochemical evidence of rejection by up to 36 h. Seven cases had damped signals throughout the post-operative period which precluded assessment by this method. In two patients the hepatic vein signals remained pulsatile despite rejection, one patient having unsuspected tricuspid regurgitation, and the other a stenotic IVC anastomosis. In the 35 liver transplants with normal pulsatility, hepatic vein Doppler proved to be a valuable indicator of acute rejection during the first 2 weeks following transplantation (sensitivity 92%, specificity 100%, positive predictive value 100% and negative predictive value 83%).

Preliminary report: hepatic vein Doppler in the early diagnosis of acute liver transplant rejection.

37 transplanted livers (in thirty patients) were assessed by serial doppler ultrasound examination. 18 of 23 biopsy-proved rejection episodes were associated with abrupt damping of the normally pulsatile blood flow of the hepatic veins. In the other 5 episodes, the waveforms were damped at the outset by perioperative ischaemia. There were no rejection episodes with normal traces. Another cause of damping was cholangitis (5 episodes), but this was distinguishable clinically and biochemically. There were no episodes of rejection with normal hepatic vein traces. Serial doppler examination, in combination with clinical evaluation, may allow earlier diagnosis and treatment of liver rejection.

Ultrasound cystography in the diagnosis of vesicoureteric reflux.

Vesicoureteric reflux is common in children with urinary tract infection and may cause end-stage renal failure. The diagnosis is usually based on micturating cystourethrography (MCU). We describe an alternative technique using ultrasound during bladder infusion with agitated saline. Comparison of the 2 methods shows ultrasound to be 100% sensitive in the detection of grades 3 and 4 reflux. Conclusive evidence of reflux was seen in 2 cases where MCU was subsequently normal, questioning the role of MCU as the gold standard.

Ultrasound and plain X-ray screening in childhood urinary tract infection.

A group of 309 children over the age of 2 years was investigated with ultrasound and plain X-ray for suspected urinary infection. In 29 cases there were abnormal findings and in 10 the abnormalities were confirmed with cystography and intravenous urography. Of 280 children whose ultrasound and plain X-ray findings were normal, 26 re-presented with further symptoms and investigation with cystography and urography showed abnormalities in only 4. The remaining 254 children have remained well and have been spared the uncomfortable and potentially dangerous examinations of cystography and urography.

Bladder instability and denervation in patients with bladder outflow obstruction.

In vitro pharmacological studies were performed on endoscopic detrusor biopsies from patients with bladder outflow obstruction. Urodynamic studies had been undertaken to detect the presence of bladder instability. Muscle strips from patients with instability demonstrated supersensitivity to acetylcholine and reduction in nerve mediated responses, as compared with strips from stable bladders. These changes are interpreted as suggesting the presence of cholinergic denervation in obstructed patients with bladder instability.