S C H Chan

Queen Elizabeth Hospital, Hong Kong, Hong Kong

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Publications (9)8.79 Total impact

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    ABSTRACT: Vesicoureteric reflux has been associated with paediatric urinary tract infection. Fluoroscopic micturating cystourethrography (MCU) has been the gold standard of diagnostic test for decades; however, it has been criticized owing to its lower detection rate and radiation dose to children. Therefore, new radiation-free reflux imaging modalities have been developed, in which ultrasound-based contrast-enhanced voiding urosonography (ceVUS) is a good example. However, ultrasonography has been considered as an operator-dependent examination. Therefore, our study aimed to examine the inter-observer agreement of this sonographic technique, which has not been evaluated before. Moreover, the second-generation ultrasound contrast SonoVue has been recently marketed, and the data on its efficacy on intravesical use in ceVUS is relatively scarce. Thus, we also aimed to investigate the diagnostic performance and safety profile of SonoVue-enhanced VUS in the diagnosis of vesicoureteric reflux. Our prospective comparative study compared the diagnostic performance of ceVUS with MCU in young children presenting with first episode of urinary tract infection. We performed sequential ceVUS and MCU examinations in 31 patients (62 pelvi-ureter units). Perfect inter-observer agreement (Cohen's kappa statistics = 1.0, p < 0.001) was achieved in ceVUS, suggesting its good reliability in reflux detection and grading. Using MCU as reference, ceVUS had 100 % sensitivity and 84 % specificity and carried higher reflux detection rate than MCU (p < 0.001). There was no complication encountered. Conclusion: Voiding urosonography is a reliable, sensitive, safe and radiation-free modality in the investigation of vesicoureteric reflux in children. It should be incorporated in the diagnostic algorithm in paediatric urinary tract infection.
    European Journal of Pediatrics 03/2014; 173(8). DOI:10.1007/s00431-014-2297-3 · 1.89 Impact Factor
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    H S Fung · S Lau · M K Chan · K W Tang · YL Cheung · S C H Chan ·
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    ABSTRACT: A persistent sciatic artery is a rare embryological anomaly. We report a case of a persistent sciatic artery with aneurysm formation and thrombosis in a patient with rheumatoid arthritis/systemic lupus erythematosus overlap syndrome and Raynaud's phenomenon. The diagnosis and complete, accurate evaluation of the arterial anatomy of the lower limb were achieved using computed tomographic angiography.
    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 01/2009; 14(6):492-4. · 0.87 Impact Factor
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    P C H Kwok · K K Ho · C C Ma · S S Chung · C C W Tse · P L F Tang · F S K Cheng · S C H Chan ·
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    ABSTRACT: To review the results of endovascular treatment of acute thoracic aortic diseases in a group of Chinese patients. Retrospective study. A tertiary referral hospital with a cardiothoracic surgery service. All 15 patients presenting with acute thoracic aortic diseases between September 2001 and October 2005 inclusive, of whom eight had traumatic rupture, four had complicated acute dissections, two had mycotic aneurysms, and one an aneurysm with an aortobronchial fistula. Thoracic aortic stent grafting. Immediate success, 6-month and 1-year survival rates. The median follow-up period was 20.6 months (range, 0-50.1 months). Stent grafts were deployed with immediate success in all patients. Two patients had ancillary bypass surgery for the supra-aortic branches. There were two in-hospital deaths. Four sustained access artery injury and needed graft repair. Computed tomography at 1 month showed complete thrombosis of the aneurysmal lumen or the thoracic aortic false lumen in 12 of 13 survivors. Computed tomography at 6 months showed complete thrombosis of the aneurysmal lumen or the false lumen in nine of 10 patients due for follow-up. Both 6-month and 1-year survival rates were 87%. Thoracic aortic stent grafting for acute thoracic aortic disease is feasible and has a high success rate, with good short-to-midterm results. However, the large size of the stent graft introducer set imposes a high risk of access artery injury, for which further improvements are necessary.
    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 11/2006; 12(5):355-60. · 0.87 Impact Factor
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    H L J Mak · P C H Kwok · H H L Chau · M K Chan · S C H Chan · S C S Chan ·
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    ABSTRACT: To evaluate the medium-term results of uterine fibroid embolisation in Chinese women with symptomatic uterine fibroids. Prospective case series study. Gynaecology and Interventional Radiology units in a public hospital, Hong Kong. Patients with symptomatic fibroids who underwent uterine fibroid embolisation in Queen Elizabeth Hospital from October 1998 to June 2004. Fifty women (mean age, 42.9 years; median follow-up period, 27.5 months) were recruited. Most (82%) had menorrhagia as the chief presenting symptom. Embolisation was successful in 49 (98%) women. Complications occurred in 12 (24%) patients, but were all self-limiting. Significant decrease in the median clinical uterine size (14 weeks vs 10 weeks) and median volume of the largest fibroid on magnetic resonance imaging (157.9 mL vs 45 mL) were observed during the first year. The reduction seemed to be maintained till the last follow-up. Menorrhagia improved in 34 (84%) patients, dysmenorrhoea in 28 (88%), pelvic pain in 18 (82%) and abdominal mass in 15 (83%). Poor response was found for urinary symptoms (29% improvement). Eight (16%) patients underwent hysterectomies after uterine fibroid embolisation. On logistic regression analysis, the only significant predictive factor for symptomatic improvement was fibroid volume reduction at 6 months (P=0.03). Uterine fibroid embolisation is an effective uterine-preserving therapy in patients with symptomatic fibroids; overall symptomatic improvement was estimated as 80%. Uterine or fibroid size reduction correlated well with clinical outcome. The impact of uterine fibroid embolisation on young women wishing to conceive is yet to be determined.
    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 11/2006; 12(5):361-7. · 0.87 Impact Factor
  • S.S.M. Lo · K.W. Siu · T.K. Tsang · K.Y. Kwok · A.M.W. Wai · H.S. Fung · F.C.Y. Lam · S.C.H. Chan ·
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    ABSTRACT: Foreign body ingestion is not uncommon but the majority of foreign objects ingested traverse the gastrointestinal tract without complications. We report a case of retroperitoneal abscess in a 38-year-old man following perforation of the colon by an ingested toothpick.
    Journal of the Hong Kong College of Radiologists 01/2005; 8(4):254-255.
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    P C H Kwok · K K Ho · T K M Chung · S C H Chan · A K H Lai · A C Y Chan · C L Liu ·
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    ABSTRACT: To investigate the role of aortic stent grafting in emergency treatment of traumatic rupture of the descending thoracic aorta in patients with multiple injuries. Retrospective study. Cardiothoracic surgery facility of a tertiary referral hospital, Hong Kong. Between September 2001 and September 2002, four patients who had sustained a blunt injury to the chest after high-speed deceleration injury were recruited. Three patients were treated with stent grafting because concomitant head injury and multiple other injuries precluded the use of open thoracic surgery. One patient had no head injury and was offered stent grafting as a less invasive treatment. The pseudoaneurysm was covered with an aortic stent graft under fluoroscopic and angiographic guidance. Technical success of treatment, complications, and treatment outcome. Three patients recovered and were discharged from hospital. The computed tomography scan at 3 months to 6 months after surgery showed resolution of the pseudoaneurysm. The final patient was still in the hospital. Follow-up computed tomography 2 weeks later showed exclusion of the pseudoaneurysm. There was one external iliac artery thrombosis on the side of femoral arteriotomy, which was recanalised with thrombectomy. There was another unintentional partial coverage of the left subclavian artery, which was asymptomatic. No other major complication was present and there was no paraplegia after the stent grafting. Aortic stent graft is useful for emergency treatment of descending thoracic aortic injury. In the short term, it causes less morbidity and mortality than does open surgery, and can be life-saving when there is no surgical alternative. The long-term effect is still unknown.
    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 01/2004; 9(6):435-40. · 0.87 Impact Factor
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    P C H Kwok · T W Lam · C L Lam · A K H Lai · H Y Lo · S C H Chan ·
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    ABSTRACT: We report two rare cases of acute pulmonary complication after transarterial chemoembolisation for inoperable hepatocellular carcinoma. Both cases involved a large tumour and hepatic vein invasion. The first patient, a 27-year-old man, died of pulmonary tumour embolism 4 days after transarterial chemoembolisation. Acute dyspnoea developed in the second patient, a 63-year-old man, following the procedure due to pulmonary oil embolisation and chemical pneumonitis. The chest condition of this patient improved, but he subsequently died of liver failure 3 weeks later. Our cases illustrate the point that if locoregional treatment is offered as a palliative treatment, patients with hepatic vein invasion should be warned of the possible complications of massive tumour embolism, pulmonary oil embolisation, and subsequent death.
    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 01/2004; 9(6):457-60. · 0.87 Impact Factor
  • C M Chan · K M Cheng · J Y L Cheung · F W T Lee · K W Tang · C H Tse · S C H Chan ·
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    ABSTRACT: Patients with dural arteriovenous fistula (DAVF) are at higher risk of developing neurological deficits when there is retrograde leptomeningeal venous drainage. Our aim is to demonstrate the presence of dilated deep medullary veins in the brain on magnetic resonance imaging (MR) in this group of patients, and to assess their clinical significance. Nine patients with angiographically proven DAVF associated with leptomeningeal venous drainage who had MR before treatment were studied.MR was performed in at least two orthogonal planes before and after gadolinium administration. The dural fistula was located at the cavernous sinus in five patients, at the transverse-sigmoid sinus in three and at the tentorium in one. Dilated deep medullary veins were noted in six patients. Of these, four showed parenchymal abnormalities which included intracerebral haematoma, venous infarction, brain oedema and T2 hyperintensity in brainstem. Venous varix was present in one patient. No neurological complication or parenchymal change was observed in the three patients without dilated deep medullary veins. Therefore, in patients with intracranial DAVF associated with leptomeningeal venous recruitment, the MR finding of dilated deep medullary veins suggests a more severe degree of venous hypertension and congestion in the brain. This subgroup of patients has a much higher chance of neurological complications and warrants urgent intervention.
    Interventional Neuroradiology 09/2002; 8(3):265-72. · 0.78 Impact Factor
  • A.K.H. Lai · P.C.H. Kwok · S.W. Man · R.S.F. Lau · S.C.H. Chan ·
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    ABSTRACT: An evaluator-blinded randomized clinical trial was undertaken to assess the effectiveness and patient acceptance of three bowel cleansing regimens: conventional cleansing enema, Pico-salax and Golytely. One hundred and fifty patients, referred for barium enema examination, were allocated to one of the three regimens. Both the radiographers and the radiologists did not know the method of preparation. Radiographers were requested to enter the patients' data, the number of bowel openings, the patients' comments of the preparation and side effects. Films were reviewed independently by two experienced radiologists for the degree of bowel cleanliness and quality of barium coating. The mean (standard deviation) of bowel opening frequency for the cleansing enema, Pico-Salax and Golytely were 3.6(4.4), 8.3(4.8) and 7.1(4.2), respectively, with less bowel opening in the cleansing enema. There was less nausea associated with the cleansing enema (P = 0.006), more vomiting with Golytely (P = 0.008), less abdominal fullness with Pico-salax (P = 0.0006), less anorectal irritation with Golytely (P = 0.025), and no difference in the abdominal pain amongst three groups. There was no statistically significant difference in the number of bowel openings between the groups. Patients found that Pico-salax tasted better than Golytely (P = 0.0094) and Golytely was less accepted in the amount of fluid intake (P = 0.0018 and P < 0.0002 comparing Golytely with the cleansing enema and Pico-salax). Chi-squared testing showed no statistically significant difference in bowel cleanliness and quality of barium coating among the three preparations. There was no difference in the effectiveness of the three regimens. Pico-salax seems the most acceptable because it has the fewest side effects.
    Clinical Radiology 09/1996; 51(8):566-9. DOI:10.1016/S0009-9260(96)80137-1 · 1.76 Impact Factor