Contrast-enhanced ultrasound in gallbladder disease: a pictorial review.

With its excellent contrast and spatial resolution, and the ability to image in real-time, ultrasound is the main imaging modality for assessing the gallbladder (GB). The application of contrast-enhanced ultrasound (CEUS) of the GB is now increasingly recognized as a useful addition to ultrasound and other cross-sectional imaging in the assessment of neoplastic and non-neoplastic GB disease. With the ability to image microcirculation and optimal contrast resolution, CEUS allows high-quality delineation in real-time, allowing for increased diagnostic confidence. In addition, ultrasound contrast agents have a favorable safety profile and can be used if CT or MR contrast agents are contraindicated or undesired. In this review, the CEUS appearances of a range of GB diseases encountered are presented, including adenomyomatosis, polyps, carcinoma, sludge, and cholecystitis with mural ulceration or perforation.

The changing place of liver biopsy in clinical practice: an audit of an Australian tertiary hospital.

Liver biopsy is an important tool in hepatology, with a role now generally limited to cases of diagnostic uncertainty. A retrospective audit performed at the Royal Melbourne Hospital aimed to identify the indications for liver biopsy and its impact on management. Ten per cent (20/195) of biopsies lacked a strong clinical indication, with hepatology involvement in only 8/20. We recommend prior hepatologist assessment to minimise unnecessary biopsies.

Ultrasound in chronic liver disease.

BACKGROUND: With the high prevalence of diffuse liver disease there is a strong clinical need for noninvasive detection and grading of fibrosis and steatosis as well as detection of complications. METHODS: B-mode ultrasound supplemented by portal system Doppler and contrast-enhanced ultrasound are the principal techniques in the assessment of liver parenchyma and portal venous hypertension and in hepatocellular carcinoma surveillance. RESULTS: Fibrosis can be detected and staged with reasonable accuracy using Transient Elastography and Acoustic Radiation Force Imaging. Newer elastography techniques are emerging that are undergoing validation and may further improve accuracy. Ultrasound grading of hepatic steatosis currently is predominantly qualitative. CONCLUSION: A summary of methods including B-mode, Doppler, contrast-enhanced ultrasound and various elastography techniques, and their current performance in assessing the liver, is provided. TEACHING POINTS: • Diffuse liver disease is becoming more prevalent and there is a strong clinical need for noninvasive detection. • Portal hypertension can be best diagnosed by demonstrating portosystemic collateral venous flow. • B-mode US is the principal US technique supplemented by portal system Doppler. • B-mode US is relied upon in HCC surveillance, and CEUS is useful in the evaluation of possible HCC. • Fibrosis can be detected and staged with reasonable accuracy using TE and ARFI. • US detection of steatosis is currently reasonably accurate but grading of severity is of limited accuracy.

Guidelines and good clinical practice recommendations for contrast enhanced ultrasound (CEUS) in the liver--update 2012: a WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS.

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS) using contrast specific imaging techniques. This joint WFUMB-EFSUMB initiative has implicated experts from major leading ultrasound societies worldwide. These liver CEUS guidelines are simultaneously published in the official journals of both organizing federations (i.e., Ultrasound in Medicine and Biology for WFUMB and Ultraschall in der Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis and improve the management of patients worldwide.

Radiology teaching: essentials of a quality teaching programme.

Medical student teaching is an important component of radiology education. Despite the practice of radiology undergoing significant changes during the last two or three decades, the importance of radiology has not translated fully into medical school curricula in Australia and New Zealand. This article reviews the essential components of a quality medical student teaching programme.

Spiral computed tomography-intravenous cholangiography with three-dimensional reconstructions for imaging the biliary tree.

This study aimed to assess the ability of CT-i.v. cholangiography to show the perihilar biliary and cystic duct anatomy and to assess the relative performance of axial, maximum intensity projection and surface rendered displays. We also assessed the correlation between serum bilirubin levels and adequacy of biliary opacification. Spiral CT was carried out following infusion of 100 mL of Biliscopin in 181 patients with suspected biliary disease. The display of biliary anatomy was of high quality, with 91% of patients having good opacification of at least first-order bile ducts and 84% having good opacification of at least third-order right and left hepatic ducts. The quality of biliary opacification correlated inversely to serum bilirubin levels, with levels above two to three times the normal value being associated with lower rates of good opacification. Maximum intensity projection and surface rendered reformats aided anatomical interpretation to a similar degree. The relative frequency of types of perihilar branching patterns and cystic duct junctional anatomy correlated closely to those reported from previous anatomical studies.

Bile duct varices presenting as a porta hepatis mass.

Bile duct varices are a rare manifestation of portal vein cavernous transformation. They can present as an apparent enhancing, vascular mass in the porta hepatis and are readily diagnosed using ultrasound and CT modalities. Diagnosis is important to avoid unnecessary intervention and concomitant risk of haemobilia.

Treatment of renovascular disease with percutaneous stent insertion: long-term outcomes.

Renal artery stenosis is a common, progressive cause of hypertension and renal impairment, and is frequently treated with percutaneous transluminal dilatation and stenting. The outcome of this procedure is still being evaluated. The records of 198 consecutive patients who had stents inserted at the Royal Melbourne Hospital were analysed retrospectively, and adequate follow-up information on 148 (75%), in whom a total of 182 renal arteries had been treated was obtained. Technical success was achieved in 144 patients (97%). Complications occurred in 19 patients (13.3%), with major complications occurring in 10 (7.0%) and one death occurring in relation to the procedure. A fall in average systolic blood pressure of 13.2 mmHg (12.1-14.3 mmHg) was seen and a fall in diastolic blood pressure of 10.1 mmHg (9.3-10.9 mmHg), without an increase in the number of antihypertensive drugs used. Renal function remained stable in the majority of patients, particularly those who had minimal baseline renal impairment. Restenosis was common after 6 months, occurring eventually in 29% of screened patients, but was not shown to affect clinical outcomes. Insertion of renal artery stents is a safe and effective treatment for renal artery stenosis.

Pancreatic head melanoma producing obstructive jaundice: magnetic resonance characteristics aiding differentiation from adenocarcinoma.

A case is reported of malignant melanoma presenting as a mass in the head of the pancreas producing obstructive jaundice. On MR imaging the mass displayed signal characteristics not typical of adenocarcinoma but instead exhibited a low signal on T2-weighted images and early phase dynamic enhancement, the combination of which should suggest the possibility of melanoma.

Doppler ultrasound (pre- and post-contrast enhancement) for detection of recurrent stenosis in stented renal arteries: preliminary results.

The purpose of the present paper was to assess whether conventional renal Doppler ultrasound and the commonly used parameters of peak systolic velocity and renal aortic ratio may be an appropriate modality for the follow-up of renal artery stents. A total of 19 arteries in 15 patients was examined with both renal Doppler ultrasound and angiography for the presence or absence of recurrent renal artery stenosis. Disease was considered present on angiography if the arterial diameter was more than 60% stenotic. Doppler criteria for stenosis were either a peak systolic velocity of > 180 cm/s or a renal aortic ratio of > 3.0. Echo enhancement with Levovist (Schering, Berlin, Germany) was used if studies were technically unsuccessful or to improve diagnostic confidence. Renal Doppler ultrasound detected 100% of renal artery stenoses. The specificity was 75%, the positive predictive value was 67% and the negative predictive value was 100%. Echo enhancement improved the technical success rate from 89 to 95% and also increased diagnostic confidence in six examinations. The present limited study suggests that similar renal Doppler parameters as used for the study of unstented renal arteries may be applied to the examination of renal arteries with renal stents in situ. It therefore suggests that Doppler ultrasound may provide an adequate non-invasive means of renal artery stent follow-up, particularly when combined with echo-enhancing agents. Further study is warranted to confirm these initial conclusions.

Using Doppler sonography to reveal renal artery stenosis: an evaluation of optimal imaging parameters.

OBJECTIVE: The aim of this study was to determine the accuracy of direct and indirect parameters for the diagnosis of renal artery stenosis and to determine the most useful thresholds for these parameters. SUBJECTS AND METHODS: One hundred twenty-five arteries in 63 patients were examined with renal Doppler sonography and angiography for the presence or absence of renal artery stenosis. Arteries were considered stenosed on angiography if there was a diameter reduction of greater than 60%. Renal Doppler sonographic measures of peak systolic velocity, renal aortic ratio, acceleration time, and acceleration were recorded and compared with the angiographically determined presence or absence of disease. RESULTS: Doppler examination was technically successful in 87% of kidneys and 76% of patients. Receiver operating characteristic analysis showed the optimal peak systolic velocity threshold to be 180 cm/sec and the optimal renal aortic ratio threshold to be 3.0. An acceleration time greater than 70 msec and an acceleration less than 300 cm/sec2 yielded sensitivities of 41% and 56%, respectively, and specificities of 85% and 62%, respectively. Combining a renal aortic ratio of greater than 3.0 or peak systolic velocity greater than 180 cm/sec provided the best combination of parameters with a sensitivity and sensitivity at 85% and 76%, respectively. CONCLUSION: The most accurate use of parameters was found to be a combination of either peak systolic velocity greater than 180 cm/sec or renal aortic ratio greater than 3.0. Indirect parameters were not found to be useful in predicting the presence or absence of renal artery stenosis.

Comparison of two Doppler ultrasound criteria for grading cervical internal carotid artery stenosis.

In a review of 49 carotid arteries that had been assessed by ultrasound and angiography, two Doppler criteria were compared for accuracy in grading internal carotid artery (ICA) stenosis. The Seattle criteria for Doppler spectral analysis and the internal-to-common carotid artery peak systolic velocity ratio were of similar accuracy. When used in combination, there was an increase in sensitivity compared with the use of a single criterion. The velocity ratio had a higher sensitivity for detection of high-grade stenosis, but it tended to overestimate the grade of stenosis more than the Seattle criteria. To increase the sensitivity for detection of severe stenosis, the criteria should be used together and the higher grade of stenosis should be taken if there is a mismatch in assessment.

Contrast-enhanced Doppler ultrasound for renal artery stenosis.

The use of renal artery Doppler ultrasound for the diagnosis of renal artery stenosis is a well-established technique in selected populations, but the technical failure rate of the examination leading to incomplete studies is a major drawback. The results of ultrasound contrast-enhanced renal artery Doppler for renal artery stenosis, using the echo-enhancing agent, Levovist, are reported here. Sixteen patients (22 arteries) were examined with Levovist. The technical success rate of these examinations was 91%, and all four renal artery stenoses were correctly identified. It is concluded that the use of ultrasound contrast (Levovist) increases the technical success rate of renal artery Doppler ultrasound in this setting, with similar accuracy to unenhanced Doppler examinations.

Magnetic resonance cholangiopancreatography.

Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive imaging method for examining the biliary and pancreatic ducts. The technique uses heavily T2-weighted imaging, which produces high signal from bile and other static fluids by virtue of their long T2 time, while suppressing background signal. Fast scanning techniques, particularly half-Fourier fast spin-echo techniques, are continuing to improve image resolution and allow scans within short breath-holds, reducing the effects of respiratory movement. The MRCP method has reached a level of resolution and reliability where it may well largely replace diagnostic endoscopic retrograde cholangiopancreatography (ERCP) in the near future. A review of MRCP techniques and imaging findings is presented with emphasis on half-Fourier imaging, with reference to potential clinical indications and limitations. Use of MRCP shows a high sensitivity and specificity for detection of biliary dilatation, calculi, strictures and anatomical variants. Experience with MR imaging of the pancreatic duct is less extensively described in the literature, but pancreatic duct dilatation, calculi and anatomy can now be reliably detected. However, as experience with MRCP increases, some sources of errors and limitations are becoming apparent, with image artefacts, and gas, blood or sludge within ducts potentially mimicking stones or strictures.

MRI of the liver.

MRI of the liver is a powerful imaging modality for detection and characterization of liver pathology. MRI technology continues to evolve with developments in scanner hardware performance and refinements in imaging sequences, particularly in respect to fast imaging techniques, improving the quality of images that can be routinely achieved. Fast imaging techniques allow dynamic contrast-enhanced scanning to assist in lesion detection and characterization. An array of tissue-specific contrast agents are also becoming available; the clinical utility of some of these agents is yet to be fully established. An overview of scanning technique, contrast media, and the role of MRI in liver lesion detection and characterization is presented, with a review of the typical imaging characteristics of common focal and diffuse hepatic diseases. Where possible, emphasis has been placed on features that allow distinction between the various pathologic entities described.

Percutaneous transjejunal biliary intervention: 10-year experience with access via Roux-en-Y loops.

PURPOSE: To assess the safety and efficacy of percutaneous retrograde transjejunal cholangiography and biliary intervention for benign and malignant disease. MATERIALS AND METHODS: The clinical and radiographic records of 43 patients (31 with benign and 12 with malignant disease) who had undergone percutaneous retrograde transjejunal biliary intervention over a 10-year period at a single institution were reviewed. One hundred eighty-one procedures were performed via a fixed Roux-en-Y loop and 15 via an unfixed loop. RESULTS: Percutaneous retrograde transjejunal cholangiography was attempted on 196 occasions (143 for benign and 53 for malignant disease). Primary successful access was obtained in 181 (92.3%). Adjunctive percutaneous transhepatic cholangiography improved successful access in an additional seven procedures, to 188 (95.9%). Interventions included stricture dilation, stone extraction, stent insertion, and brachytherapy. The mean number of biliary interventions and the mean interval between them were 3.1 interventions and 5.9 months in the benign group and 3.6 interventions and 3.8 months in the malignant group. The complication rate was 4.1%, with no deaths or episodes of biliary sepsis. CONCLUSION: Percutaneous transjejunal biliary access allows repeated interventions over many years with a low morbidity. Routine superficial fixation of Roux-en-Y loops is recommended for all biliary-enteric anastomoses to allow use of this safe and effective approach for any subsequent biliary intervention.

A comparison of Doppler flowmetry with conventional assessment of acute changes in hepatic blood flow.

The validity and clinical relevance of Doppler flowmetry in measuring changes in regional blood flow are uncertain. In the present study we compared changes induced ketanserin in regional splanchnic blood flow as measured by Doppler flowmetry with changes in conventionally measured systemic and in hepatic haemodynamic indices estimated pharmacokinetically using indocyanine green. Fourteen patients with alcoholic cirrhosis and portal hypertension were evaluated. On multivariate analyses, significant associations were noted for only three indices: changes in estimated hepatic blood flow were predicted jointly by changes in flow in the main and right portal veins and hepatic artery (R2 = 0.80); changes in intrahepatic shunting (indocyanine green extraction) were predicted by changes in flow in the main and right portal veins (R2 = 0.55); and changes in sinusoidal perfusion (indocyanine green clearance) were significantly predicted by changes in main portal vein flow alone (R2 = 0.76). These data support the validity of Doppler flowmetry in quantifying change in regional blood flow, but highlight the limitations in its clinical application and interpretation. The association of changes in main portal vein flow with changes in sinusoidal perfusion has clinical potential but requires confirmation using other modulating drugs.

A home-made phantom for learning ultrasound-guided invasive techniques.

An ultrasound phantom is described which allows practice of ultrasound-guidance of needle placement over variable depths and into targets of variable size. The phantom mimics a solid organ in its echogenicity and can be cheaply and easily made from resources of the domestic kitchen.