Non-invasive evaluation of liver cirrhosis using ultrasound.

Ultrasound (US) is essential in both assessment of the potentially cirrhotic liver and surveillance of selected patients with chronic hepatitis as liver biopsy can be misleading or inaccurate in up to 25% of cases. Various techniques are already in routine use, such as grey-scale imaging, Doppler US, and contrast-enhanced US (CEUS), while newer techniques such as elastography and hepatic vein transit time (HVTT) have the potential to exclude patients without significant fibrosis or cirrhosis; however, they are operator dependent and require specific software. Grey-scale imaging may demonstrate changes, such as volume redistribution, capsule nodularity, parenchymal nodularity, and echotexture changes. The Doppler findings in the hepatic and portal veins, hepatic artery, and varices allow assessment of liver cirrhosis. However, the operator needs to be aware of limitations of these techniques. Low mechanical index CEUS plays an important role in the assessment of complications of cirrhosis, such as hepatocellular carcinoma and portal vein thrombus. Optimized US technique is crucial for accurate diagnosis of the cirrhotic liver and its complications.

Renal transplant sonography: correlation of Doppler and biopsy results in cellular rejection.

Seventy-one patients with allograft dysfunction had concomitant Doppler sonography and percutaneous biopsy. Forty-one had biopsy proven acute cellular rejection and eight had acute cellular rejection in combination with acute tubular necrosis. Real time ultrasonic appearance and various parameters of Doppler waveform were studied and compared with 30 controls who had a long period of stable function with no previous episodes of rejection or acute tubular necrosis (ATN). Morphological appearances were unhelpful in diagnosing rejection. A resistive index greater than 0.8 in the study group was highly specific for dysfunction but could not differentiate between acute rejection and ATN. However, two patients in the control group of normal transplants had a resistive index of 0.83. An early to mid diastolic notch was highly specific for acute rejection but of low sensitivity. It may be the only Doppler indication of cellular rejection and may be present when the resistive index is in the normal range.

The potential use of diuresis Doppler sonography in PUJ obstruction.

Three cases of proven PUJ (pelvi-ureteric junction) obstruction in whom duplex Doppler sonography was performed are described. In one case, there was a duplex transplant kidney with PUJ obstruction of the lower pole moiety. The resistive index of an interlobar lower pole artery was markedly elevated compared to that of an artery in the upper unobstructed moiety. In the other two cases, the resistive index of interlobar arteries of native kidneys increased significantly following intravenous frusemide simultaneous with an increase in the degree of pelvicalyceal dilatation. It is proposed that diuresis Doppler sonography may provide additional diagnostic information in patients with PUJ obstruction, and that the method warrants further evaluation.

Duplex and colour flow sonography in the diagnosis of post-biopsy arteriovenous fistulae in the transplant kidney.

Arteriovenous fistulae are a common sequel to percutaneous biopsy of the transplant kidney. The majority close spontaneously, but a proportion progress and may require embolization or surgical closure. They are characterized by a very pulsatile (arterialized) venous flow. The arteries sometimes demonstrate a low resistive index and/or high velocities, but normal values may be encountered. On colour flow Doppler the most characteristic appearance is a mosaic of colour due to a combination of tissue vibration and turbulence.

The effect of intravenous furosemide on the Doppler waveform in normal kidneys.

Duplex Doppler sonography is currently being evaluated in the differentiation of obstructive and nonobstructive hydronephrosis. It was thought that this method may be of use in the diagnosis and follow-up of pelviureteric junction obstruction, and that its sensitivity may be increased by the use of intravenous furosemide to raise the intrarenal pressure in obstructive cases. Before embarking on a formal study, a pilot study was initiated to determine the effect of furosemide on the Doppler waveform of the normal kidney. Intravenous furosemide had variable effects on peak systolic and end-diastolic velocities and little significant effect on resistive index but caused a constant and dramatic subjective increase in vascularity. Possible modes of action are discussed.

Coagulation studies and fistula blood flow during erythropoietin therapy in haemodialysis patients.

An increased incidence of fistula thrombosis has been reported in haemodialysis patients treated with recombinant human erythropoietin (rHuEpo). The present study sought to investigate this problem by measuring fistula blood flow, blood viscosity, and a variety of tests of coagulation and haemostasis in a group of ten haemodialysis patients treated with rHuEpo. Fistula blood flow did not alter during the first 12 months of rHuEpo despite a significant increase in whole-blood viscosity. Bleeding time improved in all ten patients after 4 months of therapy, and this improvement was maintained at 12 months. There were no significant changes in one-stage prothrombin time, kaolin cephalin clotting time, whole-blood clotting time, prothrombin consumption index, plasma fibrinogen factor VII, factor VIII, antithrombin III, or platelet aggregability to ADP over the first 4 months of rHuEpo. In contrast, protein C decreased from 84.3 to 66.4% (P less than 0.01) and protein S from 124.1 to 68.3% (P less than 0.001) over the first 4 months. By 8 and 12 months, the concentrations of these substances had returned to pretreatment values. The levels of protein C and S attained at 4 months are known to predispose to thrombosis, and it is possible that this effect may contribute to the increased incidence of fistula thrombosis observed in haemodialysis patients treated with rHuEpo.

Long-term cardiorespiratory effects of amelioration of renal anaemia by erythropoietin.

The long-term cardiorespiratory effects of recombinant human erythropoietin treatment were investigated in ten haemodialysis patients by means of maximum exercise testing, lung function tests, echocardiography, chest X-ray, and rheological assessment over 12 months. There were significant rises in exercise time (mean [SD] 13.2 [5.5] to 20.0 [6.2] min), maximum oxygen consumption (19.1 [7.0] to 25.0 [6.7] ml.min-1.kg-1), and anaerobic threshold (11.7 [3.6] to 15.4 [4.8] ml.min-1.kg-1) after 2 months of erythropoietin treatment. The improvements were maintained but not augmented on repeat testing after 4, 8, and 12 months of therapy. Carbon monoxide transfer [corrected] rose from 15.5 (2.9) to 18.6 (3.7) ml.min-1.mm Hg-1. There was a substantial reduction in exercise-induced cardiac ischaemia (eight patients had significant ST segment depression before erythropoietin, only one after 2 months' treatment, and none after 12 months' treatment), despite a significant rise in whole blood viscosity. Left ventricular mass, as estimated by echocardiography, progressively decreased from 354 (169) g to 251 (95) g after 12 months' treatment, and four patients showed a reduction in cardiothoracic ratio on chest X-ray.

Sonographic and computed tomographic features of polycystic disease of the liver.

Three cases of polycystic disease of the liver (PCL) are reported. Sonography (US) and computed tomography (CT) are diagnostic and the characteristic features are described.

Duplex Doppler ultrasound in the diagnosis of acute renal allograft rejection.

As renal transplantation becomes more commonplace and successful, there is an increasing demand for non-invasive methods of studying possible complications. One hundred and fifty-four duplex Doppler sonography scans were performed in 38 patients within 52 days of receiving a renal allograft. Renal vascular impedance was estimated in the intrarenal arteries by calculating the resistive index ([peak systolic frequency shift--lowest diastolic frequency shift]/peak systolic frequency shift). A resistive index of greater than 0.80 was very suggestive of rejection (positive predictive value 82%); with a value of less than 0.70 rejection was unlikely (negative predictive value, 98%).

Ultrasound changes in the transplant kidney.

The purpose of this trial was to study the ultrasound changes that take place in a non-selected group of transplant kidneys in the post-operative period and to identify the ultrasound signs that most accurately identify episodes of acute rejection. It was found that in patients with no episodes of rejection or acute tubular necrosis the ultrasound appearances of the kidney progressed in a predictable way to reach a stable picture similar to the non-transplanted kidney after 2 weeks. Those patients who had episodes of early rejection, but subsequently 'settled down' to a stable state had a similar progress between rejection episodes but the ultimate stable appearance of the kidney varied greatly. Those patients with recurrent rejection episodes, leading to eventual failure of the transplanted kidney, had an unpredictable sequence of ultrasound changes. These findings demonstrate that early rejection episodes may permanently affect the appearance of the kidney and this makes interpretation of future scans difficult unless a baseline scan is available for comparison. The comparison of cortico-medullary echogenicity with a baseline scan makes ultrasound a more specific test than previously reported, but does not improve the poor sensitivity.

Conjoined twins. Antenatal ultrasound diagnosis and a review of the literature.

Three sets of conjoined twins recently diagnosed by us in the antenatal period are presented. From these cases and a review of the literature we present the ultrasound diagnostic features of the various forms of this rare condition. We discuss the importance of associated anomalies and shared organs with their relevance to subsequent antenatal management and delivery. The importance of excluding this condition whenever twins are diagnosed on ultrasound is stressed.

Effects of two ultrasound scanning regimens on the management of pregnancy.

Two obstetric ultrasound scanning regimens were compared with each other and with two control groups by studying the effects on the management of pregnancy. One group of women was scanned routinely whilst the other was scanned only for specific clinical indications. Management was improved in both the scanned groups compared with that in the control groups, mainly in the mode and timing of delivery and in the admission pattern during pregnancy. Routine scanning resulted in more accurate early detection of placenta praevia and multiple pregnancy but there was no improvement in the management of labour compared with that in the group scanned only for specific reasons.

The value of ultrasound in previously undiagnosed renal failure.

Rapid advances in equipment and diagnostic criteria have made ultrasound sufficiently sensitive to replace high-dose urography (with its attendant risks and often lengthy examination time) as the initial imaging modality in renal failure. A prospective study was carried out in 56 patients (109 kidneys). All hydronephroses were accurately detected on ultrasound. 80% were due to obstruction, but showed no features that distinguished them from other causes of hydronephrosis. A diagnostic pathway is suggested.

Ultrasound of the fetal spine.

The sonographic appearance of the fetal spine was studied using a dynamic section (real time) machine in 7000 pregnancies. The interpretation of the appearance was verified by the use of aborted fetuses and models in a water bath, and by clinical outcome. Twenty-nine cases of spina bifida occurred in the series, 12 with associated anencephaly, 17 with a spinal defect alone. Analysis of results by clinical outcome and ultrasonic examination of aborted abnormal fetuses show that cases with significant vertebral body and/or lateral mass abnormalities could be detected with good accuracy (91%) but those with only neural arch defects were not accurately detected, making the overall accuracy 79%. The spine is visualised in two longitudinal planes. The cranio-cervical junction is well shown in the dorsal sagittal plane, while the sacrum is identified by its characteristic curve in the sagittal plane and by its relation to the iliac bones in the coronal plane. Gaps in the lines representing the neural canal are produced by sonic shadows in the iliac bones and shoulders in the coronal planes and by the soft tissues of the extended neck in the sagittal plane. An oblique view of the gluteal region may mimic a soft tissue swelling. A third line between the two representing the neural canal is due to the transverse processes of the vertebrae.