Perfluorobutane contrast-enhanced ultrasonography: a new standard for ultrasonography-guided thermal ablation of sonographically occult liver tumours?

INTRODUCTION@#Image-guided thermal ablation, preferably with ultrasonography (US), is increasingly used for treatment of small liver tumours. Perfluorobutane-contrast-enhanced US (pCEUS) is a promising tool that may allow for targeting of tumours that are otherwise imperceptible on greyscale US. Although pCEUS has been reported to be effective, the literature has been limited outside of Japan and South Korea. We aimed to provide data that supports the use of pCEUS in the thermal ablation of sonographically occult liver tumours.@*METHODS@#We conducted a retrospective single-centre study of 35 consecutive patients who underwent pCEUS-guided ablation of 48 liver tumours with a median size of 1.2 cm. Periprocedural, one-month post-treatment and relevant follow-up imaging studies were reviewed. Electronic records were also obtained, with long-term follow-up data of 12-28 months being available for 32 patients.@*RESULTS@#36 (75%) tumours that were imperceptible on greyscale US became visible with pCEUS. Overall, complete tumour ablation at one month was 89%. 1 (3%) patient developed a major complication following treatment, while 6 (17%) had minor post-treatment complaints. The local tumour progression rate was 17%, with a median time of 14 months.@*CONCLUSION@#pCEUS has a role in US-guided thermal ablation of liver tumours, offering a high technical success rate that is comparable to reported data. Additional benefits may include improved procedural time and freedom from ionising radiation.

Single-centre retrospective review of risk factors for local tumour progression and complications in radiofrequency ablation of 555 hepatic lesions

INTRODUCTION@#This study aimed to assess safety, local tumour progression (LTP) and risk factors for LTP after radiofrequency ablation (RFA) of liver tumours in a single centre.@*METHODS@#All consecutive patients treated with RFA for liver tumours between January 2009 and October 2012 were included. Previously treated lesions that progressed were excluded. Using electronic medical records, the following data was captured: patient demographics, pre-procedural laboratory results, Child-Pugh status, tumour characteristics, development of tumoral seeding, RFA complications and LTP. Possible risk factors for LTP were identified using Cox regression.@*RESULTS@#In total, 555 liver tumours were treated in 337 patients. 483 (87.0%) hepatocellular carcinomas, 52 (9.4%) colorectal metastases and 20 (3.6%) other tumour types were treated. Mean tumour size was 2.1 ± 1.1 (range 0.4-6.8) cm. Mean follow-up duration was 387 days. 416 (75.0%) lesions had no LTP at the last imaging. 70 (12.6%) patients had minor complications requiring observation, while 7 (1.3%) patients had significant complications requiring prolonged hospitalisation or further interventions. Only one case of tumour seeding was detected. Using multivariate Cox regression, the following factors were statistically significant in predicting LTP: hilar location (relative ratio [RR] 3.988), colorectal metastases (RR 2.075), size (RR 1.290) and younger age (RR 0.982).@*CONCLUSION@#RFA of liver tumours is safe and effective, with a low significant complication rate of 1.3%. Hilar lesions are most prone to LTP, followed by lesions that were larger in size and colorectal metastases. 75.0% of patients showed no LTP at the last follow-up.

Percutaneous Endovascular Treatment to Salvage Non-Maturing Arteriovenous Fistulas in a Multiethnic Asian Population

<p><b>INTRODUCTION</b>An arteriovenous fistula (AVF) is the preferred method for haemodialysis in patients with end-stage renal failure. Previous studies have shown value in attempting percutaneous transluminal angioplasty (PTA) to salvage AVFs that fail to mature, but they are relatively small in size and mainly reported in Western populations. We reviewed our data of PTA in non-maturing AVFs to establish whether this technique is translatable to our local multiethnic population.</p><p><b>MATERIALS AND METHODS</b>We retrospectively reviewed the medical records and procedural images of 105 patients who had PTA for non-maturing AVFs performed at our department from January 2008 to January 2011. Technical success was defined as ≤30% residual stenosis after angioplasty. Clinical success was defined as at least 1 successful haemodialysis session within 4 weeks after PTA.</p><p><b>RESULTS</b>All 105 patients underwent angioplasty for at least 1 haemodynamically significant stenosis. Six (5.7%) had additional embolisation of accessory veins. Technical success was achieved in 95.2% of cases. The clinical success rate was 76.2%. Primary patency rates at 3, 6 and 12 months were 83%, 45% and 28%, respectively. Secondary patency rates at 3, 6 and 12 months were 90%, 79% and 70%, respectively. The minor complication rate was 18.1%. No major complications were encountered. An average of 1.7 interventions per access-year was required to maintain AVF patency. Patients with a preoperative vein size >2.0 mm and age <55 years were more likely to achieve clinical success, although not statistically significant.</p><p><b>CONCLUSION</b>PTA is a viable option to help salvage non-maturing AVFs in a multiethnic Asian population.</p>

Application of a standardised protocol for hepatic venous pressure gradient measurement improves quality of readings and facilitates reduction of variceal bleeding in cirrhotics

<p><b>INTRODUCTION</b>Hepatic venous pressure gradient (HVPG) measurement is recommended for prognostic and therapeutic indications in centres with adequate resources and expertise. Our study aimed to evaluate the quality of HVPG measurements at our centre before and after introduction of a standardised protocol, and the clinical relevance of the HVPG to variceal bleeding in cirrhotics.</p><p><b>METHODS</b>HVPG measurements performed at Singapore General Hospital from 2005-2013 were retrospectively reviewed. Criteria for quality HVPG readings were triplicate readings, absence of negative pressure values and variability of ≤ 2 mmHg. The rate of variceal bleeding was compared in cirrhotics who achieved a HVPG response to pharmacotherapy (reduction of the HVPG to < 12 mmHg or by ≥ 20% of baseline) and those who did not.</p><p><b>RESULTS</b>126 HVPG measurements were performed in 105 patients (mean age 54.7 ± 11.4 years; 55.2% men). 80% had liver cirrhosis and 20% had non-cirrhotic portal hypertension (NCPH). The mean overall HVPG was 13.5 ± 7.2 mmHg, with a significant difference between the cirrhosis and NCPH groups (p < 0.001). The proportion of quality readings significantly improved after the protocol was introduced. HVPG response was achieved in 28 (33.3%, n = 84) cirrhotics. Nine had variceal bleeding over a median follow-up of 29 months. The rate of variceal bleeding was significantly lower in HVPG responders compared to nonresponders (p = 0.025).</p><p><b>CONCLUSION</b>The quality of HVPG measurements in our centre improved after the introduction of a standardised protocol. A HVPG response can prognosticate the risk of variceal bleeding in cirrhotics.</p>

Single centre experience of transjugular liver biopsy in 152 patients

<p><b>INTRODUCTION</b>Liver biopsy is considered the definitive investigation in the diagnosis and management of liver disease. This study describes the experience of performing transjugular liver biopsy (TJLB) over the last 9 years in a local single centre.</p><p><b>MATERIALS AND METHODS</b>A retrospective review of consecutive TJLB procedures performed at our institution was conducted. A total of 152 patients (74 males and 78 females), with a mean age of 47.4 years (range, 13 to 83 years) underwent a total of 154 TJLB procedures at our institution between March 2003 and November 2011. The principal indication for TJLB was severe coagulopathy in over 80% of patients. The technical success, number of passes, histological adequacy and complication rates were analysed.</p><p><b>RESULTS</b>The procedural success rate was 98.7% (152 out of 154 procedures). Adequate material for diagnosis was obtained in 149 out of 152 (98.0%) technically successful procedures. There was procedure related morbidity in 8 patients (5.2%) of which all but one were self-limiting requiring no further intervention. We also performed hepatic venous pressure gradient (HVPG) measurements in 19% of patients at the time of TJLB.</p><p><b>CONCLUSION</b>TJLB performed at our institution is a safe and reliable technique in patients in whom traditional percutaneous liver biopsy may be hazardous. TJLB has a high technical success rate as well as a high diagnostic yield with a low complication rate. TJLB also has the added benefit of performing HVPG, which is of increasing importance in management and prognostication of chronic liver disease.</p>

Supplementary breast ultrasound screening in Asian women with negative but dense mammograms-a pilot study

<p><b>INTRODUCTION</b>Dense breasts are common in Asian women and they limit the sensitivity of mammography. This study evaluates the performance of supplementary breast ultrasound screening in Asian women with dense mammograms.</p><p><b>MATERIALS AND METHODS</b>The study was approved by the hospital's Institutional Review Board. A prospective clinical trial was performed between September 2002 and November 2004. Asymptomatic Asian women with negative and dense mammograms were offered supplementary ultrasound screening for breast cancer. Ultrasound assessment was categorised as U1 to U4. U1 and U2 cases were recommended routine interval screening mammography. U3 cases were recommended follow-up ultrasound in 6 months and routine interval screening mammography and U4 cases were recommended biopsy.</p><p><b>RESULTS</b>One hundred and forty-one women with mean age of 45.1 years were enrolled into the study. Mean scan time was 13.0 minutes (± 5.6 minutes) for bilateral vs 11.0 minutes (± 1.4 minutes) for unilateral scans. There were 10 patients and 14 patients in the in the U3 and U4 categories, respectively. Two U4 category patients were diagnosed with malignancy-a-6 mm ductal carcinoma-in-situ and a 13- mm invasive ductal carcinoma. The breast cancer detection rate was 1.4%. Sensitivity and specifi city were 100% (2/2) and 88.5% (92/104) respectively. The positive predictive value was 14.3% (2/14) and the negative predictive value was 100% (92/92).</p><p><b>CONCLUSION</b>This pilot study reveals the usefulness of supplementary ultrasound screening in detecting early stage mammographically and clinically occult breast cancers in Asian women with dense breasts. A larger long-term study is, however, needed to assess its feasibility and impact on breast cancer prognosis.</p>

Stent-assisted percutaneous angioplasty for extra-cranial carotid disease:experience at Singapore General Hospital

<p><b>INTRODUCTION</b>This study aims to analyse the results of carotid stenting in a tertiary referral centre in Singapore.</p><p><b>MATERIALS AND METHODS</b>Retrospective analysis of all carotid artery stenting (CAS) cases in a single centre from March 1997 to December 2008 was performed. Sixty successful procedures were performed in 61 patients, with bilateral stenting in 1 patient, and 2 failed procedures. The majority were Chinese (78.7%) and males (77.0%), with a high proportion having hypertension (82.0%) and hypercholesterolaemia (78.7%). The majority (91.8%) of patients were high surgical risk candidates, primarily due to cardiac risk factors. Ten patients (16.4%) had prior neck irradiation for nasopharyngeal carcinoma, and 3 patients each (4.9%) had previous endarterectomy and contralateral occlusion. A distal embolic protection device was used in 71.7% of cases.</p><p><b>RESULTS</b>Technical success was 96.8%. The 30-day stroke and death rate was 13.8%, comparable to reported results for this high surgical risk population.</p><p><b>CONCLUSION</b>CAS is a technically feasible and a relatively safe alternative to endarterectomy to treat extracranial carotid stenosis, especially in patients who are inoperable or at high surgical risk.</p>