Radiology - Research Publications
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ItemTwo decades of percutaneous transjejunal biliary intervention for benign biliary disease: a review of the intervention nature and complications.(Springer Science and Business Media LLC, 2011-10)OBJECTIVE: To assess outcomes of percutaneous transjejunal biliary intervention (PTJBI) in terms of success and effectiveness in patients with a Roux-en-Y hepaticojejunostomy for benign biliary strictures and stones. METHODS: Clinical and radiographic records of 63 patients with a Roux-en-Y choledochojejunostomy or hepaticojejunostomy for benign disease who underwent at least one PTJBI between 1986 and 2007 were reviewed. Effectiveness was determined by successful access rate, rates of stricture dilatation and/or stone extraction, morbidity, complications and hospitalisation. RESULTS: PTJBI was attempted 494 times. Successful access to the Roux-en-Y was accomplished in 93% of interventions. After access to the Roux-en-Y was granted, all strictures were effectively dilated. Ninety-seven percent of extraction attempts of intrahepatic calculi were successful. The median number of interventions per patient was five. The median interval between interventions was 51.5 weeks (range 2.7-1,279.6 weeks). The early complication rate was 3%. Morbidity, measured in terms of cholangitis episodes was 14%, in 25 out of 63 patients. Mean hospitalisation was 4.1 nights per year. CONCLUSION: PTJBI is safe and effective in treating benign biliary strictures and/or calculi. High success rates and short hospitalisation periods, together with few complications make it a well-accepted and integral part of managing complex biliary problems.
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ItemVariability of Liver Shear Wave Measurements Using a New Ultrasound Elastographic Technique(WILEY, 2018-03)OBJECTIVES: A new 2-dimensional (2D) shear wave elastographic (SWE) device has been developed for the noninvasive assessment of liver fibrosis. Guidelines on measurement acquisition parameters are not yet well established for this technique. Our study aimed to assess 2D SWE measurement variability and to determine the number of measurements required per patient to reliably assess liver stiffness. METHODS: Two-dimensional SWE was assessed in 55 patients with mixed-etiology chronic liver disease on an Aplio 500 ultrasound system (Toshiba Medical Systems Corporation, Tochigi, Japan). Ten measurements were obtained per patient by an operator blinded to all preceding readings. Results were analyzed with clinical information obtained from medical records. RESULTS: The median interquartile range/median ratio for 2D SWE was 0.131 (quartiles 1-3, 0.089-0.174). Five readings provided an approximation within 0.11 m/s, or 4.2% of the median velocity of 10 measurements. Factors associated with increased measurement variability included body mass index (ρ = 0.388; P = .01), increased skin-to-liver capsule distance (ρ = 0.426; P = .002), and measurements taken within 1.5 cm of the liver capsule (P < .001). Measurements with heterogeneous shear wave profiles (indicated by a region of interest [ROI] SD/speed ratio > 0.15) showed greater deviation from the set's median velocity than those with an ROI SD/speed ratio of 0.15 or lower (0.42 versus 0.22 m/s; P = .001). CONCLUSIONS: Two-dimensional SWE showed low overall measurement variability, with a minimum of 5 readings providing equivalent precision to the existing method using 10 samples. Obesity, increasing abdominal wall thickness, subcapsular measurements and an ROI SD/speed ratio of greater than 0.15 were all associated with increased measurement variability. The ROI SD/speed ratio warrants further evaluation as a quality assessment metric, to allow objective operator assessment of individual 2D SWE measurement reliability in real time.
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ItemTargeted ultrasound of the liver: Impact on scanning time of a new approach in chronic liver disease(WILEY, 2017-08)INTRODUCTION: Targeted ultrasound of the liver (TUSL) has been proposed as a new approach in chronic liver disease to meet the increasing demands on ultrasound services in this patient population. This study analyses the impact of TUSL on examination time. METHODS: Retrospective cohort analysis of time taken to perform liver ultrasound on consecutive chronic liver disease patients pre- (n = 230) and post- (n = 147) introduction of TUSL. Within each cohort, patients were subdivided into three categories based on the clinical indication: Group 1. hepatocellular carcinoma (HCC) surveillance; Group 2. detection of cirrhosis, fibrosis or fatty liver; Group 3. detection of portal hypertension. The primary outcome was difference in examination time in the pre- and post-intervention groups. RESULTS: Introduction of TUSL led to 49% reduction in examination time (median (Q1-Q3) 23.7 (16.7-36.2) min in pre-TUSL period vs 12.1 (6.4-19.5) min in post, P < 0.001) and it was consistent across all three clinical indication groups (gr1: median 23.1 minutes vs 8.1 minutes (P < 0.001), gr2: 23.0 minutes vs 14.3 minutes (P < 0.001), gr3: 32.2 minutes vs 15.3 minutes (P = 0.006)). After the adjustment for clinical indication and sonographer's experience, impact of TUSL on time reduction remained significant with a 66.6% time reduction (95% CI 53.6 to 79.5). CONCLUSION: Targeted ultrasound of the liver improves efficiency of chronic liver disease ultrasound with halving of examination times and consequently has the potential to greatly improve resource utilization.
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ItemAcoustic radiation force impulse accuracy and the impact of hepatic steatosis on liver fibrosis staging(WILEY, 2016-10)INTRODUCTION: The accuracy of Acoustic Radiation Force Impulse (ARFI) imaging has been validated in the setting of hepatitis C, however, the accuracy in the setting of fatty liver disease (FLD) has been less well-established. The aim of this study was to assess the accuracy of ARFI in the setting of hepatic steatosis. METHODS: Patients with biopsy proven or sonographically diagnosed liver steatosis were assessed for ARFI trends including: inter-operator concordance, interquartile range, ARFI failure rate, relationship between ARFI velocity and steatosis severity, and concordance between biopsy and ARFI fibrosis scores. RESULTS: Three hundred and forty-nine patients were assessed (53 'biopsy' cohort and 296 'ultrasound' cohort), with 28 patients having biopsy on the same day as ARFI. Low stages of fibrosis (F0/1) were over-estimated by ARFI in 62% of cases with biopsy correlation (n = 16, P < 0.001), with ARFI offering increased accuracy in regard to higher-stage fibrosis (14/15 cases, 93%). In both the biopsy and ultrasound cohorts the failure rate and median inter-quartile range increased with increasing steatosis, and the inter-operator concordance remained good across all liver steatosis severities. CONCLUSION: In the setting of steatosis, ARFI is very sensitive in detecting, and accurate in diagnosing, higher stages of fibrosis regardless of steatosis severity. It tends to overestimate the fibrosis category in lower stages of fibrosis. The present study does not show conclusively if the presence of steatosis or its severity independently alters ARFI measurements.
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ItemUltrasound in chronic liver disease.(Springer Science and Business Media LLC, 2014-08)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.
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ItemSkin-Liver Distance and Interquartile Range-Median Ratio as Determinants of Interoperator Concordance in Acoustic Radiation Force Impulse Imaging(WOLTERS KLUWER MEDKNOW PUBLICATIONS, 2019)CONTEXT AND AIMS: The accuracy of acoustic radiation force impulse (ARFI) ultrasound compared to liver biopsy is higher when there is concordance between F-scores of two or more operators. We hypothesized that when the first operator interquartile range/median-velocity ratio (IMR) is <0.3 and skin-liver distance (SLD) is <2.5 cm, there is greater interoperator concordance and a second operator is not necessary. SUBJECTS AND METHODS: Two-operator ARFI ultrasound measurements (F-score, SLD, and IMR) were recorded for 927 consecutive patients. Chi-squared testing compared interoperator concordance for SLD <2.5 cm versus SLD ≥2.5 cm and IMR <0.3 versus IMR ≥0.3 when SLD <2.5 cm, in each of the F-score groups of 0/1, 2, 3, and 4. RESULTS: Statistically significant differences were demonstrated between SLD <2.5 cm and SLD ≥2.5 cm groups for F-scores 0/1 or 4 (P = 0.005) and F-scores 2 or 3 (P < 0.001). Concordance, when SLD measured <2.5 cm, was more than 85% for all F-score groups. In the SLD <2.5 cm group, concordance fell below 85% when IMR ≥0.3, for all F-scores except F2. Specifically, P values comparing IMR <0.3 and IMR ≥0.3 in the various first operator F-score groups were P = 0.040 for F0/F1, P = 0.580 for F2, P = 0.342 for F3, and P < 0.001 for F4. CONCLUSIONS: ARFI measurements from one operator can be considered acceptable when SLD <2.5 cm and IMR <0.3. Otherwise, adding a second operator can improve confidence in the result.
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ItemSurveillance of FAP: a prospective blinded comparison of capsule endoscopy and other GI imaging to detect small bowel polyps(BMC, 2010-04-04)BACKGROUND: Familial adenomatous polyposis (FAP) is a hereditary disorder characterized by polyposis along the gastrointestinal tract. Information on adenoma status below the duodenum has previously been restricted due to its inaccessibility in vivo. Capsule Endoscopy (CE) may provide a useful adjunct in screening for polyposis in the small bowel in FAP patients. This study aims to evaluate the effectiveness of CE in the assessment of patients with FAP, compared to other imaging modalities for the detection of small bowel polyps. METHOD: 20 consecutive patients with previously diagnosed FAP and duodenal polyps, presenting for routine surveillance of polyps at The Royal Melbourne Hospital were recruited. Each fasted patient initially underwent a magnetic resonance image (MRI) of the abdomen, and a barium small bowel follow-through study. Capsule Endoscopy was performed four weeks later on the fasted patient. An upper gastrointestinal side-viewing endoscopy was done one (1) to two (2) weeks after this. Endoscopists and investigators were blinded to results of other investigations and patient history. RESULTS: Within the stomach, upper gastrointestinal endoscopy found more polyps than other forms of imaging. SBFT and MRI generally performed poorly, identifying fewer polyps than both upper gastrointestinal and capsule endoscopy. CE was the only form of imaging that identified polyps in all segments of the small bowel as well as the only form of imaging able to provide multiple findings outside the stomach/duodenum. CONCLUSION: CE provides important information on possible polyp development distal to the duodenum, which may lead to surgical intervention. The place of CE as an adjunct in surveillance of FAP for a specific subset needs consideration and confirmation in replication studies. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12608000616370.