Comparison of pharmacological thrombolysis with mechanical thrombectomy in thrombosed arteriovenous fistulas and grafts: a systemic review and meta-analysis

AIM

To compare the effectiveness and safety of pharmacological thrombolysis and mechanical thrombectomy.

MATERIAL AND METHODS

This review was conducted in accordance with the PRISMA guidelines. Pooled proportions and subgroup analysis were calculated for primary and secondary patency rates, technical success, clinical success, major and minor complications rates.

RESULTS

This systematic review identified a total of 6,492 studies of which 17 studies were included for analysis. A total of 1,089 patients comprising 451 (41.4 %) and 638 (58.6 %) patients who underwent thrombolysis and mechanical thrombectomy procedures, respectively, were analysed. No significant differences were observed between thrombolysis and mechanical thrombectomy procedures in terms of technical success, clinical success, major and minor complications rates, primary and secondary patency rates; however, subgroup analysis of overall arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) demonstrated a significantly higher rate of major complications within the AVF group (p=0.0248).

CONCLUSION

The present meta-analysis suggests that pharmacological thrombolysis and mechanical thrombectomy procedures are similarly effective and safe; however, AVFs are subject to higher major complications compared to AVGs.

Deeper may not be better: relationship between catheter dysfunction and location of the catheter tip in right-sided tunnelled haemodialysis catheters

AIM

To examine the relationship between catheter tip location and catheter dysfunction in the context of tunnelled central venous catheters (CVCs) for haemodialysis.

MATERIALS AND METHODS

This was a retrospective study of 993 haemodialysis patients who underwent insertion of tunnelled CVCs of step-tip design via the right internal jugular vein (IJV). Based on intra-procedural radiographs, the catheter tip was characterised as being in the superior vena cava (SVC), cavo-atrial junction (CAJ), or deep right atrium (DRA). Patients were tracked for 90 days post-procedure for complications resulting in catheter replacement, and these were compared between cohorts. Statistical analysis was performed with Pearson's chi-square and Fisher's exact tests for categorical variables and two-sample t-test and one-way analysis of variance (ANOVA) for continuous variables.

RESULTS

Ninety-five patients (9.6%) experienced catheter dysfunction necessitating replacement within 90 days of insertion. Tip location in SVC was associated with lower occurrence of catheter dysfunction (1.9%) as compared with the CAJ (8%) and DRA (11%; p=0.049). Catheter replacement due to other complications (catheter-associated bacteraemia, cuff dislodgement, exit-site infection, external catheter damage) showed no statistically significant relation to location of the CVC tip.

CONCLUSION

When utilising tunnelled CVCs with a step-tip design inserted via the right IJV, location of the catheter tip in the SVC is associated with reduced occurrence of catheter dysfunction as compared to either the CAJ or DRA.

Pre-Operative Embolisation of Musculoskeletal Tumours - A Single Centre Experience

Introduction

The management of musculoskeletal tumours is complex and requires a multi-disciplinary approach. Preoperative embolisation can be often employed to reduce intra-operative blood loss and complication rates from surgery. We report our experience with the safety, technical success and efficacy of pre-operative embolisation in musculoskeletal tumours.

Materials and Methods

Thirteen consecutive patients who underwent pre-operative embolisation of a musculoskeletal tumour followed by surgical intervention at our institution from May 2012 to January 2016 were enrolled into the study. Patient demographics, tumour characteristics, embolisation techniques and type of surgery were recorded. Technical success of embolisation, amount of blood loss during surgery and transfusion requirements were estimated.

Results

There were five female and eight male patients who underwent pre-operative embolisation during the study period. The age ranged between 16 to 68 years, and the median age was 54. Technical success was achieved in all patients. Mean intra-operative blood loss was 1403ml, with a range of 150ml to 6900ml. Eight patients (62%) required intra-operative blood products of packed red blood cells and fresh frozen plasma. No major complications occurred during embolisation.

Conclusion

Pre-operative trans-arterial embolisation is feasible and safe for a variety of large and hypervascular musculoskeletal tumours. Our small series suggests that preoperative embolisation could contribute to the reduction of the intra-operative and post-operative blood product transfusion. It should be considered as a pre-operative adjunct for major tumour resections with a high risk of bleeding. The use of the haemoglobin gap complemented the assessment of perioperative blood loss.

Mercury in dental amalgam: Are our health care workers at risk?

Dental amalgam in fillings exposes workers to mercury. The exposure to mercury was investigated among 1871 dental health care workers. The aim of the study was to evaluate the risk of mercury exposure among dental compared to nondental health care workers and to determine other risk factors for mercury exposure. Respondents answered questionnaires to obtain demographic, personal, professional, and workplace information and were examined for their own amalgam fillings. Chronic mercury exposure was assessed through urinary mercury levels. In total, 1409 dental and 462 nondental health care workers participated in the study. Median urine mercury levels for dental and nondental health care workers were 2.75 μg/L (interquartile range [IQR] = 3.0175) and 2.66 μg/L (IQR = 3.04) respectively. For mercury exposure, there were no significant risk factor found among the workers involved within the dental care. The Mann-Whitney test showed that urine mercury levels were significantly different between respondents who eat seafood more than 5 times per week compared to those who eat it less frequently or not at all (p = 0.003). The urinary mercury levels indicated significant difference between dental workers in their practice using squeeze cloths (Mann-Whitney test, p = 0.03). Multiple logistic regression showed that only the usage of cosmetic products that might contain mercury was found to be significantly associated with the urinary mercury levels (odds ratio [OR] = 15.237; CI: 3.612-64.276). Therefore, mean urinary mercury levels of health care workers were low. Exposure to dental amalgam is not associated with high mercury exposure. However, usage of cosmetic products containing mercury and high seafood consumption may lead to the increase of exposure to mercury.

IMPLICATIONS

Exposure to the high levels of mercury from dental amalgam can lead to serious health effects among the dental health care workers. Nationwide chronic mercury exposure among dental personnel was assessed through urinary mercury levels. Findings suggest low urinary mercury levels of these health care workers. Exposure to dental amalgam is not associated with high mercury exposure. However, the usage of cosmetic products containing mercury and high seafood consumption may lead to the increase of exposure to mercury.

Mutant p53-R273H mediates cancer cell survival and anoikis resistance through AKT-dependent suppression of BCL2-modifying factor (BMF)

p53 is the most frequently mutated tumor-suppressor gene in human cancers. Unlike other tumor-suppressor genes, p53 mutations mainly occur as missense mutations within the DNA-binding domain, leading to the expression of full-length mutant p53 protein. Mutant p53 proteins not only lose their tumor-suppressor function, but may also gain new oncogenic functions and promote tumorigenesis. Here, we showed that silencing of endogenous p53-R273H contact mutant, but not p53-R175H conformational mutant, reduced AKT phosphorylation, induced BCL2-modifying factor (BMF) expression, sensitized BIM dissociation from BCL-X_L and induced mitochondria-dependent apoptosis in cancer cells. Importantly, cancer cells harboring endogenous p53-R273H mutant were also found to be inherently resistant to anoikis and lack BMF induction following culture in suspension. Underlying these activities is the ability of p53-R273H mutant to suppress BMF expression that is dependent on constitutively active PI3K/AKT signaling. Collectively, these findings suggest that p53-R273H can specifically drive AKT signaling and suppress BMF expression, resulting in enhanced cell survivability and anoikis resistance. These findings open the possibility that blocking of PI3K/AKT will have therapeutic benefit in mutant p53-R273H expressing cancers.

Heavy fermions. Unconventional Fermi surface in an insulating state

Insulators occur in more than one guise; a recent finding was a class of topological insulators, which host a conducting surface juxtaposed with an insulating bulk. Here, we report the observation of an unusual insulating state with an electrically insulating bulk that simultaneously yields bulk quantum oscillations with characteristics of an unconventional Fermi liquid. We present quantum oscillation measurements of magnetic torque in high-purity single crystals of the Kondo insulator SmB6, which reveal quantum oscillation frequencies characteristic of a large three-dimensional conduction electron Fermi surface similar to the metallic rare earth hexaborides such as PrB6 and LaB6. The quantum oscillation amplitude strongly increases at low temperatures, appearing strikingly at variance with conventional metallic behavior.

Pilot study evaluating catheter-directed contrast-enhanced ultrasound compared to catheter-directed computed tomography arteriography as adjuncts to digital subtraction angiography to guide transarterial chemoembolization

AIM

To investigate the feasibility and procedural value of catheter-directed contrast-enhanced ultrasound (CCEUS) compared with catheter-directed computed tomography arteriography (CCTA) in patients undergoing transarterial chemoembolization (TACE) guided by digital subtraction angiography (DSA).

MATERIALS AND METHODS

From December 2010 to December 2011, a pilot study was conducted including nine patients (mean age 66.6 years; SD 8.3 years; seven men) undergoing TACE with drug-eluting beads for unresectable hepatocellular carcinoma (HCC). Both CCEUS and CCTA were performed in addition to DSA. Alterations of treatment plan based on CCEUS were recorded and compared with CCTA.

RESULTS

CCEUS provided additional information to DSA altering the treatment plan in four out of nine patients (44.4%). In these four patients, CCEUS helped to identify additional tumour feeders (n = 2) or led to a change in catheter position (n = 2). The information provided by CCEUS was similar to that provided by CCTA.

CONCLUSION

CCEUS is a potentially valuable imaging tool in adjunction to DSA when performing TACE and may provide similar information to CCTA.

Adjuvant hepatic intra-arterial iodine-131-lipiodol following curative resection of hepatocellular carcinoma: a prospective randomized trial

BACKGROUND

The purpose of the present study was to determine whether intrahepatic injection of (131)I-lipiodol (Lipiodol) is effective against recurrence of surgically resected hepatocellular carcinoma (HCC).

METHODS

From June 2001 through March 2007, this nationwide multi-center prospective randomized controlled trial enrolled 103 patients 4-6 weeks after curative resection of HCC with complete recovery (52: Lipiodol, 51: Control). Follow-up was every 3 months for 1 year, then every 6 months. Primary and secondary endpoints were recurrence-free survival (RFS) and overall survival (OS), respectively, both of which were evaluated by the Kaplan-Meier technique and summarized by the hazard ratio (HR). The design was based on information obtained from a similar trial that had been conducted in Hong Kong.

RESULTS

The Lipiodol group showed a small, and nonsignificant, improvement over control in RFS (HR = 0.75; 95 % confidence interval [95 % CI] 0.46-1.23; p = 0.25) and OS (HR = 0.88; 95 % CI 0.51-1.51; p = 0.64). Only two serious adverse events were reported, both with hypothyroidism caused by (131)I-lipiodol and hepatic artery dissection during angiography.

CONCLUSIONS

The randomized trial provides insufficient evidence to recommend the routine use of (131)I-lipiodol in these patients.

Fluoroscopy-guided, transcervical, selective salpingography and fallopian tube recanalisation

This study is a retrospective review of the transcervical fluoroscopy-guided fallopian tube recanalisation (FTR) procedures done in a multi-ethnic south-east Asian population, over 9 years. A total of 100 patients with infertility and documented proximal tubal obstruction (PTO) were referred for FTR. On-table hysterosalpingography under sedation demonstrated true PTO in 96 patients. At selective-salpingography, the PTO cleared in 16 patients; 78 required FTR and two had fimbrial blockage. The technical success rate of FTR was 86.8% and the post-FTR pregnancy rate was 36.84% at a mean follow-up interval of 12.2 months. There were no major, immediate procedure-related complications. There was an ectopic pregnancy in a single treated patient. Fluoroscopy-guided FTR is a safe treatment option in patients with infertility from PTO, with high technical success rate, low complication rate and increased chances of pregnancy; therefore it should be preferred before attempting more expensive and resource-intensive procedures.

Retrospective analysis of results of treatment for nasopharyngeal carcinoma in Penang General Hospital from 2001-2005

BACKGROUND

Nasopharyngeal carcinoma (NPC) is one of the commonest cancers encountered in Malaysia. This study aimed to evaluate the treatment outcomes for patients with NPC treated in Penang General Hospital with specific analysis of prognostic clinicopathological features and treatment modalities.

MATERIALS AND METHODS

This retrospective study examined NPC patients between 1st January 2001 and 31st December 2005 in Penang General Hospital. Survival analyses were performed using the Kaplan-Meier method and comparisons between groups were made using the log-rank test. Important prognostic factors including patient demographics, tumour and treatment factors were analysed using the Cox proportional hazard model.

RESULTS

A total of 285 patients were identified with a median age of 51 years, 72.6% being males. The majority were Chinese (66%) followed by Malays (31.9%). Primary tumour stages (T stages) 3 and 4 were present in 18.6% and 34% of patients respectively, and nodal disease was present in 80.4%. On overall AJCC staging, 29.1% had stage III and 50.2% had stage IV disease. Some 39.6% of patients had WHO type 3 histology and 7.4% had WHO type 1-2 histology with the remainder having NPC with no subtype reported. Concurrent chemo-irradiation was the commonest treatment received by patients (51.9%) followed by radiotherapy alone (41.8%). The 5 year overall survival and cause specific survival were 33.3% and 42.7% respectively. Age group, T stage, N stage and WHO histological subtype were independent prognostic factors for overall survival on multivariate analysis. For cause specific survival they were T stage and N stage.

CONCLUSION

The 5 years overall survival rate was 33.3%. This low figure is primarily due to late presentation. Efforts to detect NPC at earlier stages in Malaysia are urgently needed. These should include public education to increase awareness of the prevalence of this highly treatable disease.

Self-expanding nitinol stents in recanalisation of long-length superficial femoral artery occlusions in patients with critical limb ischaemia

INTRODUCTION

This study aims to evaluate our experience with self-expanding nitinol stent- enabled recanalisation of long-length occlusions (30 cm or more) of the superficial femoral artery (SFA).

METHODS

573 patients underwent 842 lower limb interventions from August 2006 to December 2008. A retrospective review of patients undergoing recanalisation of long-length SFA occlusions with self-expanding nitinol stents and an evaluation of their patency and impact on limb salvage, were done.

RESULTS

22 patients (mean age 62.5 years, male: female ratio 11:11) underwent 22 long-length SFA stenting procedures. The spectrum of critical limb ischaemia included rest pain (five), ulcer (six) and gangrene (11). Length of occlusions varied from 30 cm to 45 cm (average length 36.4 cm). Five patients had stents placed through the ipsilateral popliteal artery approach, and the rest had stents placed through the femoral artery approach. All patients were followed up over an average duration of 12 months. One patient died due to associated medical conditions during this period. Six out of 21 (28.6 percent) of the stents thrombosed completely on one year follow-up. Of these, two patients underwent amputation, one patient had a bypass, and the stent in two patients were recanalised with balloon angioplasty. All remaining patent stents showed varying degrees of stenoses at one year. The overall limb salvage rate at one year following stent placement was 81 percent.

CONCLUSION

Our experience showed the beneficial result of long-length SFA stent placement with good limb salvage outcome. Repeat interventions may be required to maintain the patency of stents in these patients.

Endovascular aortic repair: the experience of two tertiary institutions in Singapore

INTRODUCTION

Endovascular aortic repair (EVAR) has gained prominence as a means of treating aortic disease, with lower perioperative morbidity and mortality compared to open surgery. This article aimed to describe the experience of two tertiary hospitals in a Southeast Asian population.

METHODS

A retrospective review of 100 consecutive patients undergoing EVAR in two hospitals in Singapore was conducted. This included patients undergoing elective as well as emergency repair.

RESULTS

The mean duration of follow-up was 31.8 months. The mean aneurysm size was 6.3 cm and the mean length of stay was 12.1 days. 64 percent of the patients were of American Society of Anesthesiologists class III or above. The deployment success was 98 percent. Major complications (acute myocardial infarction, pneumonia, cerebrovascular accidents, renal failure, colonic infarction and spinal cord infarction) occurred in 18 patients. Perioperative mortality occurred in six percent of cases. The endoleak rate was 28 percent. Both patients with colonic infarction had a single patent internal iliac artery post-procedure, and end-stage renal failure.

CONCLUSION

Our results are comparable to published experiences in aortic stenting. Our population possibly had a higher incidence of short common iliac arteries. Revascularisation of internal iliac arteries should be considered for patients with end-stage renal failure and a single patent internal iliac artery.

Gadolinium-enhanced magnetic resonance angiography in renal artery stenosis: comparison with digital subtraction angiography

OBJECTIVES

To evaluate the accuracy of gadolinium-enhanced magnetic resonance angiography in assessing renal artery stenosis compared to catheter digital subtraction angiography.

DESIGN

Retrospective study.

SETTING

Singapore General Hospital.

PATIENTS

Records of patients who underwent magnetic resonance angiography as well as digital subtraction angiography for assessment of renal artery stenosis from January 2003 to December 2005 were reviewed.

RESULTS

There were 27 patients (14 male, 13 female) with a mean age of 62 (range, 44-77) years. There were 10 patients with renal transplants; their native renal arteries were not evaluated. Each of the two experienced interventional and body magnetic resonance radiologists, who were blinded to the results, reviewed the digital subtraction angiography and magnetic resonance angiography images respectively. Digital subtraction angiography was used as the standard of reference. A total of 39 renal arteries from these 27 patients were evaluated. One of the arteries was previously stented and could not be assessed with magnetic resonance angiography due to severe artefacts. Of the remaining 38 renal arteries, two were graded as normal, seven as having mild stenosis (<50%), eight as having moderate stenosis (> or =50% but <75%), and 21 as having severe stenosis (> or =75%). Magnetic resonance angiography and digital subtraction angiography were concordant in 89% of the arteries; magnetic resonance angiography overestimated the degree of stenosis in 8% and underestimated it in 3% of them. In the evaluation of clinically significant renal artery stenosis (> or =50%) with magnetic resonance angiography, the overall sensitivity, specificity, positive predictive value, and negative predictive value were 97%, 67%, 90%, and 86% respectively. The sensitivity and specificity of magnetic resonance angiography in transplant renal artery stenosis was 100%. CONCLUSION. Our experience suggested that gadolinium-enhanced magnetic resonance angiography is a sensitive non-invasive modality useful in the assessment of clinically significant renal artery stenosis.

High-average-power mid-infrared ZnGeP2 optical parametric oscillator with a wavelength-dependent polarization rotator

A wavelength-dependent polarization rotator is used to transform the orthogonal polarizations of the signal and idler of a near-degenerate type II KTP optical parametric oscillator (OPO) into a common polarization state. This common polarization allows a single ZnGeP2 OPO to fully utilize the 2 microm signal and idler KTP OPO outputs in a mid-IR conversion. The simple design of the wavelength-dependent polarization rotator yields a compact source that simultaneously generates four mid-JR wavelengths collinearly with a total mid-IR average power of 5.5 W at a >15 kHz pulse repetition rate.

Fluorosis prevalence among schoolchildren in a fluoridated community in Malaysia

OBJECTIVES

This study aims to assess the magnitude of the problem of fluorosis among 10-11 year old schoolchildren in a fluoridated area in Malaysia.

METHODS

An analytical cross-sectional design was adopted. Sampling of subjects was by a 2-stage systematic random sampling technique in Selangor, a fully fluoridated area. 1,343 10-11 year olds were assessed for fluorosis using the Dean's index.

RESULTS

The prevalence of fluorosis was 58.7% (788 subjects); 478 (35.6%) subjects exhibited very mild fluorosis, 196 (14.6%) mild, 102 (7.6%) moderate, 12 (0.9%) severe and 555 (41.3%) no fluorosis. Tooth prevalence was 30.1%. Overall, the Community Fluorosis Index (CFI) was 0.96 and ranged from 0.23 to 1.72. Fifteen out of 30 schools had CFI > 1.0 (medium public health significance).

CONCLUSIONS

The prevalence of dental fluorosis in Malaysia (mostly very mild to mild) at 58.7% is indicative of slightly above optimal levels of exposure. There were pockets of areas where fluorosis were of medium public health significance (CFI > 1.0). It must be cautioned that, fluorosis if not monitored closely, can become an increasing public health concern.

Uterine artery embolisation for symptomatic fibroids in a tertiary hospital in Singapore

INTRODUCTION

Transcatheter uterine artery embolisation (UAE) for the treatment of symptomatic uterine enlargement due to fibroids has been performed in several overseas centres with promising results. We report our experience with UAE in Singapore General Hospital.

MATERIALS AND METHODS

Twenty women with symptomatic uterine fibroids who declined surgery were treated by transcatheter UAE. The uterine arteries were selectively catheterised and embolised with polyvinyl alcohol particles. Post-procedure analgesia was administered via a patient-controlled analgesia pump. The patients were followed up at regular intervals clinically and with transabdominal ultrasonography.

RESULTS

Transcatheter UAE was performed on all patients with no major complications. Nineteen patients had both uterine arteries embolised while 1 patient had only the right uterine artery embolised on account of hypoplasia of the left uterine artery. The mean hospital stay was 3.5 days (range, 2 to 9). At a mean follow-up of 56 weeks (range, 6 to 168), all patients reported improvements in their presenting symptoms. Objective improvement in terms of reduction of uterine and fibroid sizes was determined on ultrasonography. The median size of the uterine volume decreased from 308 to 187 mL while the median diameter of the largest fibroid reduced from 6.2 to 4.6 cm. The median haemoglobin level increased to 12.7 g/dL from the pre-procedural median of 9.9 g/dL. One patient, who initially responded with a decrease in uterine and dominant fibroid size, became symptomatic (menorrhagia) at 6 months post-embolisation. She underwent a repeat procedure with complete resolution of symptoms. A second patient had recurrence of symptoms at 12 months, but was subsequently lost to follow-up.

CONCLUSION

Mid-term results of UAE for the treatment of symptomatic fibroids in our hospital indicate this to be a safe and effective therapeutic option.

Pregnancy following embolisation of uterine arteriovenous malformation--a case report

INTRODUCTION

Pregnancy following successful embolisation of a uterine arteriovenous malformation (AVM) is rare. Hypovascularity of treated areas affecting placentation and fetal growth has been postulated to be the cause for adverse pregnancy outcomes.

CLINICAL PICTURE

A 37-year-old multiparous lady presented with anaemia from repeated heavy vaginal bleeding from an iatrogenic uterine AVM. This was diagnosed with power Doppler ultrasonography and embolised after pelvis angiography with hystoacryl and lipiodol. Following this she had a spontaneous pregnancy with a normal outcome.

CONCLUSION

There are no distinguishing clinical features of a uterine AVM. An index of suspicion and power Doppler sonography help in reaching a diagnosis. Dilatation and curettage should be avoided as this can precipitate torrential vaginal bleeding.

Colorectal hepatic metastases: Role of radiofrequency ablation

INTRODUCTION

Radiofrequency ablation (RFA) is a new minimally invasive treatment that has been increasingly used in the treatment of liver metastases. This review aims to outline the principles governing the use of RFA and to examine its role when applied to the management of colorectal liver metastases.

METHODS

A Medline search of experimental and clinical studies relating to the use of RFA in the management of colorectal hepatic metastasis was carried out.

RESULTS

RFA is currently used as an alternative to surgery in patients with unresectable disease, and sometimes as its companion, allowing patients hitherto considered unsuitable for resection to become surgical candidates. RFA has been shown to be safe and well tolerated, with few major complications and minimal patient discomfort. Although its use is unlikely to achieve cure in such patients, it has a definite role in palliation and relief of symptoms. Long-term data, when these become available, may also show improved survival. However, because RFA is a local ablative therapy, it does not address the progressive and systemic nature of colorectal carcinoma.

CONCLUSIONS

RFA is an important alternative/complimentary tool in the management of colorectal hepatic metastases. Combining RFA with surgery or chemotherapy may reduce the incidence of local and systemic relapse.

Clinical utility of selective intra-arterial calcium-stimulated hepatic venous sampling in regionalisation of insulinomas--the Singapore experience

INTRODUCTION

To evaluate the efficacy and safety of selective intra-arterial calcium-stimulated hepatic venous sampling (ASVS) as a preoperative regionalisation modality for insulinomas.

DESIGN AND METHODS

Four patients with biochemically-proven endogenous hyperinsulinism and negative spiral computed tomographic (CT) pancreas were subjected to ASVS between October 1999 to May 2001. Results obtained from ASVS were compared with localisation studies using either magnetic resonance imaging (MRI) or endoscopic ultrasonography (EUS); and these were confirmed surgically whenever possible.

RESULTS

ASVS led to a definitive regionalisation in all 4 patients evaluated; the predicted location of the insulinoma matched the findings intraoperatively in all 3 patients who were operated upon. These were all proven to be insulinoma histologically. However, 1 patient showed a positive ASVS result in samples obtained from the left hepatic vein only. In the patient who was unable to undergo surgical resection due to other co-morbid factors, his ASVS findings were corroborated by localisation obtained from the MRI study. Conversely, EUS was found to give an incorrect localisation of insulinoma in 1 patient. Adverse effects were encountered in 3 patients (2 with mild hypotension and 1 with transient atrial fibrillation); however, premature termination of the procedure was not necessary in any of the patients.

CONCLUSION

ASVS is accurate and reliable for regionalisation of insulinoma, especially in patients who do not have an obvious, unequivocal tumour using high quality current-generation MRI scans.

Outcome of percutaneous nephrostomy for the management of pyonephrosis

OBJECTIVE

The aim of this study was to evaluate the efficacy of percutaneous nephrostomy (PCN) drainage for the interim management of pyonephrosis.

METHODS

Ninety-two consecutive patients [29 men, 63 women; mean age, 57 years; range, 23 to 88] who underwent PCN for the treatment of pyonephrosis from 1996 to 1999 were evaluated retrospectively. The clinical presentation, bacteriology and patient outcomes were analyzed.

RESULTS

The majority [77%] of patients had underlying obstructing urinary calculi. Other causes of obstruction included strictures [9%], papillary necrosis [7%], pelvi-ureteric junction obstruction [4%] and malignant stricture [3%]. The microorganisms cultured were Escherichia coli [30%], Klebsiella [19%], Proteus [8%], Pseudomonas [5%], Enterococcus [5%], and Candida spp [5%]. The microorganisms were sensitive to gentamicin [79%], ceftriaxone [71%], cephalexin [54%], nitrofurantoin [40%], cotrimoxazole [35%], nalidixic acid [32%] and ampicillin [29%]. Only 30% of bladder urine cultures were positive for microorganisms; the addition of PCN cultures improved this yield to 58%. The antibiotic regimen was revised according to the PCN culture whenever there was a discrepancy. After PCN, 69% of patients underwent minimally invasive procedures as definitive treatment of the obstructing lesion. Only 14% of patients required open surgery. There was low procedure-related morbidity [14%] and low overall mortality [2%].

CONCLUSIONS

PCN cultures yield important bacteriological information. The procedure is associated with minimal morbidity, facilitates definitive treatment and provides therapeutic benefit.

A case of uterine artery pseudoaneurysms

Uterine artery pseudoaneurysms is a rare cause of haemorrhage but is potentially life-threatening and can occur after common gynaecological operations such as a Caesarean section or a hysterectomy. A 33-year-old woman who developed secondary postpartum haemorrhage after a Caesarean section was diagnosed to have uterine artery pseudoaneurysms on ultrasound scan. She was treated with bilateral uterine artery embolisation via selective catherisation of uterine arteries. Good outcome with the aneurysms remaining obliterated was obtained. Angiographic embolisation is a safe and effective method of treating postpartum haemorrhage in haemodynamically stable patients and should be an option before resorting to surgery in appropriately selected cases.

Single centre review of radiologically-guided percutaneous nephrostomies: a report of 273 procedures

INTRODUCTION

To evaluate the technical success and complications associated with radiologically-guided percutaneous nephrostomies (PCNs) in a single centre.

MATERIALS AND METHODS

A total of 273 PCNs performed in 190 patients in our hospital over a 3-year period from January 1997 to December 1999 were retrospectively reviewed. The study population consisted of 97 males and 93 females, ranging in age from 13 to 91 years. The main indications were urinary obstruction (77.7%), pyonephrosis (18.3%) and urinary diversion (4%). Demographic variables, technical and risk factors related to the procedure, complications, effect on urine cultures and body temperature; and subsequent patient management were examined.

RESULTS

The technical success rate was 99%. The 30-day mortality was 7.2%, none of which were procedure related. Haemorrhage requiring transfusion occurred in 4.3% while septicaemia affected 3.2% of patients. Drainage catheter complications included catheter dislodgement and blockage which were 11.9% and 4.1%, respectively. Thirty-one per cent of PCNs subsequently underwent ureteric stenting as the definitive treatment modality.

CONCLUSION

Radiologically-guided PCN is a safe procedure with a high technical success rate.

Diagnostic accuracy of focused appendiceal CT in clinically equivocal cases of acute appendicitis

PURPOSE

To determine the diagnostic accuracy of modified focused appendiceal computed tomography (CT) to exclude or confirm appendicitis in patients who presented with equivocal symptoms and signs of appendicitis.

MATERIALS AND METHODS

One hundred patients (age range, 14-81 years; mean age, 30.6 years) with equivocal symptoms and signs of acute appendicitis were included in this prospective study. Patients were given 30 mL of diatrizoate meglumine and diatrizoate sodium and 60 mL of sorbitol mixed in 1 L of water orally over 1 hour. CT was performed 1.5 hours after the commencement of oral contrast material administration. The criteria used for the diagnosis of appendicitis were (a) appendix greater than 6 mm in maximum diameter, (b) no contrast material in the appendiceal lumen, and (c) inflammatory changes in the periappendiceal fat. CT results were compared with histopathologic findings at appendectomy. Patients with negative CT findings were followed up by telephone or clinically.

RESULTS

Of 100 cases, 30 were positive at CT and 70 were negative. There were 28 true-positive cases; two false-positive cases, one cecal diverticulitis and one pelvic peritonitis with periappendicitis; and two false-negative cases, one perforated appendix and one mucosal and submucosal inflammation of the appendix but no transmural inflammation. Sensitivity was 93%, specificity was 97%, and accuracy was 96%.

CONCLUSION

Focused appendiceal CT in which oral contrast material is used alone yields high levels of accuracy in clinically equivocal cases of acute appendicitis.

Acute renal colic: value of unenhanced spiral computed tomography compared with intravenous urography

OBJECTIVE

The objective of this study was to compare the efficacy of plain spiral computed tomographic (CT) scan with intravenous urography (IVU) in the evaluation of patients with suspected urinary calculi/obstruction.

MATERIALS AND METHODS

Twenty consecutive patients with acute signs of renal colic were prospectively examined with unenhanced spiral CT followed by an IVU within the same day. The CT scans were reviewed jointly by 2 radiologists blinded to the IVU and a consensus was reached for each finding. The IVU was similarly reviewed by another 2 separate radiologists.

RESULTS

Eleven of the 20 patients had signs of urinary obstruction on CT and IVU. Of these 11 patients, 7 had a ureteric calculus that was demonstrated on CT and IVU and 4 had a calculus that was demonstrated on CT only. Two patients had a urinary calculus seen on CT and IVU with no signs of urinary obstruction. One patient had a calculus seen on CT alone with no urinary obstruction. Two patients only had signs of urinary obstruction on CT. The remaining 4 cases had normal findings on CT and IVU.

CONCLUSION

Unenhanced CT is more effective than IVU in identifying ureteric calculi and is equally effective in detecting urinary obstruction. CT is also useful in detecting secondary signs of obstruction even in the absence of any calculus.

188rhenium-TDD-lipiodol in treatment of inoperable primary hepatocellular carcinoma--a case report

INTRODUCTION

The aim of this study was to investigate the potential of using 188Re Lipiodol for selective internal radiation therapy of inoperable hepatocellular carcinoma (HCC).

CLINICAL PICTURE

A 33-year-old female with poorly-differentiated multicentric HCC, elevated alpha-fetoprotein (AFP) and increased serum alkaline phosphatase.

TREATMENT

Over a 2-month interval, the patient was treated twice with 4GBq of 188Re-TDD-Lipiodol.

OUTCOMES

There was good localisation of 188Re Lipiodol in the tumours, but also in thyroid (first treatment) and gastrointestinal tract (both treatments). So far (5 months post-treatment), the patient remains well with stable disease.

CONCLUSIONS

188Re Lipiodol can be an effective radiopharmaceutical for the treatment of HCC; however, more work must be done to minimise the uptake in bowel.

Health beliefs in oral cancer: Malaysian estate Indian scenario

This is a study to describe the health beliefs related to oral cancer (OC) in a high-risk group in Malaysia, a predominantly Indian community living in an agricultural setting called an estate. The study population was a convenient sample of 112 adults, above 20 years of age, attending oral cancer screening in two estates. The subjects consisted of 106 (94.6%) Indians and six (5.4%) Malays. Using the Health Belief Model, the perceptions of susceptibility to OC, its severity, and the benefits of and barriers to preventive actions, as well as beliefs underlying OC aetiology were investigated. About half of the subjects (n=57, 50.9%) felt susceptible to oral cancer. A majority of subjects (n=93, 83.0%) felt that oral cancer is a severe disease. Thirty four people (30.4%) perceived OC as a preventable disease, while 56 (50%) did not, and the remaining 22 (19.6%) did not know if OC was preventable or not. The majority of subjects (84.8%) believed that modifications to the betel quid habit could be beneficial. The information solicited can be used as a starting point to design health-education activities aimed at this group in particular and the population in general.

DNA testing for fragile X syndrome in 255 males from special schools in Singapore

INTRODUCTION

Fragile X syndrome, the most common cause of inherited mental retardation, results from unstable expansion of a trinucleotide (CGG)n repeat in the FMR1 gene. Phenotypic expression is variable making clinical diagnosis difficult, while diagnosis by Southern blotting is relatively expensive and labour intensive. The prevalence in Singapore has not been studied.

MATERIALS AND METHODS

We developed a rapid screening test using a PCR analysis. We studied 255 males with unexplained cause for learning difficulties from 8 special schools. A clinical scoring system based on characteristic features described was devised.

RESULTS

PCR analysis showed absence of the band for the normal allele in 11 samples, 6 of which were confirmed by Southern blotting to be positive for FMR1 expansion, giving a 2% false-positive rate with PCR. Sensitivity of the PCR test was evaluated by performing Southern blotting in all PCR-normal samples; all of which were confirmed to be normal. This PCR test was shown to be highly reproducible. Clinical criteria were not predictive.

CONCLUSIONS

Six (2.4%) new cases of fragile X syndrome were detected. There is a need to incorporate fragile X testing in routine screening of patients with developmental delay and learning difficulties. The use of PCR could eliminate the need for Southern blotting in up to 95% of cases. PCR analysis provides a simple, reliable and rapid tool for screening.

Clinics in diagnostic imaging (44). Testicular tumour with retroperitoneal lymphadenopathy and inferior vena cava thrombosis

A 20-year-old Indian man presented with a two week history of non-specific abdominal pain. Abdominal ultrasonograpy incidentally detected a thrombus in the inferior vena cava (IVC). Computed tomography revealed the presence of extensive para-aortic lymph node disease as well as a filling defect in the IVC. Scrotal ultrasonography located a heterogeneous intra-testicular tumour in an otherwise palpably-normal testis. The extent of the IVC thrombus was evaluated by the use of magnetic resonance imaging. Inguinal orchidectomy was performed and histology revealed a non-seminomatous germ cell tumour. Combination chemotherapy led to complete resolution of lymph node disease and IVC thrombus. The patient remained well 9 months after diagnosis. The causes of IVC obstruction, role of imaging in investigating IVC obstruction and the management of tumour involvement of the IVC are discussed.

Outcome of tunnelled central venous haemodialysis catheters inserted by radiologists

Radiologists have only recently been involved in the percutaneous placement of tunnelled central venous haemodialysis catheters. We report our initial experience with our first 60 catheters. All catheters were successfully inserted. Immediate complications encountered included puncture site haemorrhage in 3 patients (5%) and puncture of the left brachiocephalic vein in 1 patient (1.7%). These were managed conservatively without any clinical sequelae. About 80% of the catheters were uncomplicated and removed electively. Slightly more than 80% of the catheters were in place for more than 30 days. Infection and blocked catheters were the most common short-term complications. Ten catheters (17%) were infected resulting in premature removal of 9. There was 1 death from presumed line sepsis. Mean duration before the onset of infection was 53 days; the rate of infection was 0.28 episodes per 100 catheter days. Five catheters (8%) were blocked or had poor flow. The mean duration before the onset of blockage was 39 days and the rate of blockage was 0.14 episodes per 100 catheter days. A higher proportion of catheters inserted from the left encountered complications. In conclusion, percutaneous insertion of tunnelled haemodialysis catheters by radiologists is safe and effective. The right internal jugular vein should be the preferred access site. Precautions should be taken to avoid infectious complications given the high rate of catheter removal amongst infected catheters.

Radiological placement of 211 central venous catheters: outcome and complications

A prospective study of 211 central venous catheters consecutively placed in 186 patients under radiological guidance was conducted over an 18-month period. The majority (64%) of our patients were at risk for acute complications or failure. These risks included bleeding tendency, distorted anatomy, or previous complicated lines and failed "blind" percutaneous attempts. We employed the subtraction angiographic technique for venous mapping or ultrasound localisation to guide our initial puncture. The accumulated catheter experience was 15,295 days and the median catheter survival time was 166 days. The success rate was 100%. Our acute complications included 1 case of arterial puncture (0.5%), 2 pneumothoraces (1.0%), and 13 patients (6.1%) with haematoma or prolonged oozing at the puncture site. The calculated infection rate was 0.25 episodes per 100 catheter days at risk. These results are comparable to those reported in the literature. We conclude that central venous catheterisation using imaging guidance is accurate and safe, and should be the method of choice especially in high-risk patients.

Partial nephrectomy for renal tumours: the Singapore General Hospital experience

From January 1991 to August 1998, 220 radical nephrectomies were performed for renal cell carcinoma (RCC). During the same period, 27 patients underwent partial nephrectomy for their renal tumours. These included 19 male and 8 female (mean age, 54; range, 35-75). Their clinical presentation, diagnostic modalities and surgical outcome were evaluated. The lesions included 18 RCCs, 7 angiomyolipomas (AMLs), 1 oncocytoma and 1 dysoncogenetic renal tumour. Only 8 patients had specific urological symptoms. Computerised tomography (CT) scan was diagnostic in 78% of cases. Tumour size ranged from 15-50 mm for RCC and 30-190 mm for AML, respectively. Operative time averaged 92 minutes (range: 35-145). The hospital stay ranged from 3 to 25 days (mean 11). Complications occurred in four cases (14.8%); there was one death (3.7%). No tumour recurrence was detected during a mean follow up of 20 months. None of the patients developed significant renal impairment. Partial nephrectomy is feasible in small RCC and some large AML, and can be offered in selected patients.

Tissue microangiography using a simplified barium sulphate cadaver injection technique

This study investigated the application of soft tissue X-ray imaging as a method of studying vascular anatomy in injected cadaveric specimens. The arterial system of the anatomical region of interest was perfused with a barium sulphate-gelatin suspension. After curing, the tissues were removed by meticulous dissection and examined using the soft tissue X-ray imaging system. This technique of microangiography was able to demonstrate the entire arterial system of the perfused specimen. This simplified technique shows great potential in the study of vascular anatomy of flaps.

Using uncovered metallic endoprostheses to treat recurrent benign esophageal strictures

OBJECTIVE

The management of recurrent benign esophageal strictures is a difficult clinical problem, especially in patients who are not surgical candidates. We evaluated the role of uncovered metallic endoprostheses in four patients who had strictures that were resistant to repeated balloon dilatation.

CONCLUSION

Our preliminary experience indicates that uncovered metallic endoprostheses can be effective in treating a select group of patients who have benign esophageal strictures and for whom multiple dilatations have failed. It is also important to note that epithelial hyperplasia can result in stenoses and recurrent dysphagia.

Human herpesvirus-6 (HHV-6) DNA and virus-encoded antigen in oral lesions

Archival oral tissues comprising 51 squamous cell carcinomas, 18 non-malignant lesions and 7 normal mucosa samples were investigated for human herpesvirus-6 (HHV-6)-encoded antigens and HHV-6 DNA. The virus-specific antigens were detected by an immunohistochemical method using monoclonal antibodies. Two further techniques used for HHV-6 DNA detection included the polymerase chain reaction (PCR) with virus-specific primers and in situ hybridization using digoxigenin-labelled oligonucleotides specific for HHV-6A and HHV-6B genotypes. A high proportion (79-80%) of the squamous cell carcinomas were positive for HHV-6 with the various detection methods. In cases of lichen planus and leukoplakia a high prevalence rate (67-100%) was noted with in situ hybridization and immunohistochemical techniques but a lower proportion (22-33%) was detected with the PCR method. All 7 normal tissues tested were negative for HHV-6. The HHV-6 variant B was found in 60% of the oral carcinoma tissues analysed. The study demonstrates the frequent presence of HHV-6 in neoplastic and non-malignant lesions of the oral cavity. While the role of HHV-6 in oral mucosal tissues remains to be determined, the in vitro tumorigenic potential of the virus suggests a possible role in the etiopathogenesis of oral lesions.

The use of metallic stents in the palliation of inoperable oesophageal carcinoma

Carcinoma of the oesophagus is the seventh most common malignancy worldwide. It is a disease with a poor prognosis; more than half of the patients present with surgically irresectable tumours. For such patients, palliative therapy is directed towards the relief of dysphagia. Expandable metallic stents have recently been developed for use in the oesophagus. These have the advantage of being introduced through small diameter delivery catheters. Once released, they can expand to as much as 25 mm in diameter, potentially allowing patients to consume a normal diet. The current designs of metallic stents include the Strecker stent, the Wallstent endoprosthesis, and the Gianturco-Rosch stent. The Strecker is an uncovered stent while the other two are covered on the outside of the stent with plastic to prevent tumour ingrowth. A review of the literature indicates that deployment of these stents is associated with a high technical success rate. Improvement in swallowing function is seen in 83% to 100% of these patients. The overall complication rates are low. However, covered stents are prone to migration while uncovered stents are vulnerable to tumour ingrowth. Further improvements in design promise to expand the role of these endoprostheses in the management of oesophageal carcinoma.

Palliation of inoperable esophageal carcinoma: a prospective randomized trial of laser therapy and stent placement

PURPOSE

A prospective, randomized comparison of the result of endoscopic laser therapy and that of placement of self-expandable metallic endoprostheses was performed to determine which method provides the best palliation of dysphagia in patients with inoperable esophageal carcinoma.

MATERIALS AND METHODS

Sixty patients participated in the study. Twenty-three were randomly assigned to undergo plastic-covered stent placement, 19 to undergo uncovered stent placement, and 18 to undergo laser therapy. The quality of swallowing was assessed with the dysphagia score, which ranged from 0 for normal swallowing to 4 for complete dysphagia.

RESULTS

The mean improvement in dysphagia score was 2 and ranged from -1 to 3 in patients who underwent placement of plastic-covered stents, was 2 and ranged from 0 to 4 in those who underwent placement of uncovered stents, and was 1 and ranged from 0 to 2 in those who underwent laser therapy. Six of 23 (26%) plastic-covered stents migrated, whereas none of the uncovered stents did so (P < .02). Tumor ingrowth through uncovered stents occurred in five of 19 patients (26%).

CONCLUSION

Placement of metallic esophageal endoprostheses is substantially better than endoscopic laser therapy for palliation of dysphagia in patients with inoperable esophageal carcinoma. Use of uncovered and plastic-covered metallic stents provides equal palliation in patients with dysphagia.

Two cases of chronic recurrent multifocal osteomyelitis: radiological and scintigraphic findings

Chronic recurrent multifocal osteomyelitis (CRMO) is an extremely rare condition, of uncertain aetiology. Since first described, in 1972, under 100 cases have been reported. It is being reported with increasing frequency, and many cases of this disease go unreported. It most commonly affects patients in childhood or adolescence. No infective agent has been identified, and antibiotics do not affect the course of the disease. We present the cases of two female children with this disorder, describe the radiological and scintigraphic findings and review the literature. Case 1 is the first reported case to our knowledge of CRMO presenting with cranial nerve palsies.

Metallic endoprostheses for malignant tracheobronchial obstruction: initial experience

PURPOSE

To assess the efficacy of the Wallstent endoprosthesis in malignant tracheobronchial obstruction.

METHODS

Seven patients with irresectable carcinoma of the bronchus were treated with nine Wallstent endoprostheses. The procedures were performed under endoscopic and fluoroscopic guidance. Wallstent endoprostheses ranging from 8-16 mm in diameter and 26-49 mm in length were deployed after balloon dilatation of the strictures.

RESULTS

All stents were successfully deployed in the desired positions. There was one procedural complication and one procedure related death. Three patients showed significant improvement in respiratory status after stenting. At a mean follow-up of 5.1 months, there has been no stent migration, fracture, or collapse. One patient had proximal tumor overgrowth that was treated with additional stent insertion. One patient died after a bout of massive hemoptysis 3 months poststenting and it was difficult to tell whether this was related to the endoprosthesis.

CONCLUSION

The use of the Wallstent endoprosthesis in malignant tracheobronchial obstruction is technically feasible.

The use of metallic stents in the treatment of malignant superior vena caval obstruction

Superior vena caval obstruction due to malignancy is conventionally treated by radiotherapy and/or chemotherapy. In patients with unresolved or recurrent obstruction after treatment, expandable metallic stents can be percutaneously placed within the vena cava for relief of symptoms. In this series, metallic stents were successfully deployed in 11 consecutive patients with bronchial carcinoma. Gianturco Z stents were used in 10 patients and Strecker stents in one. There were 2 minor procedural complications of no sequelae. All patients had partial or full relief of symptoms after the procedure. On follow-up (mean 3.9 months), 9 patients had no recurrent symptoms up till the time of death or the present time. Two patients had recurrent obstruction, both within a week of the procedure. Based on our experience, percutaneous stenting was an effective means of palliation in this group of patients when other treatment modalities failed.

Glucocorticoid action on the growth and development of insects

Cortisol increased growth and differentiation in the large milkweed insect (Oncopeltus fasciatus). The glucocorticoid significantly increased the growth of the insect as analyzed by wet and dry weights. Cortisol also stimulated the development of the insects over that of the controls during the six day bioassay.