cy chu - Academia.edu (original) (raw)
Papers by cy chu
Author name used in this publication: 王灿龙Title in Traditional Chinese: 香港書面漢語句法變異: 粵語的移用、文言的保留及其他... more Author name used in this publication: 王灿龙Title in Traditional Chinese: 香港書面漢語句法變異: 粵語的移用、文言的保留及其他Journal title in Traditional Chinese: 語言文字應用2002-2003 > Academic research: refereed > Publication in refereed journalpublished_fina
2006-2007 > Academic research: refereed > Research book or monograph (author
Congenital defects of the posterior arch of the atlas are rare, with a reported prevalence of 0.9... more Congenital defects of the posterior arch of the atlas are rare, with a reported prevalence of 0.95 to 4%. The defects have been classified into five types (A-E), with type A being most common and types B-E being found only in 0.69% of the general population. Although most patients are asymptomatic, some may present with chronic neck pain, headache, Lhermitte’s sign, transient quadriparesis or even acute neurological deficits. The defects may also mimic a Jefferson fracture leading to a wrong diagnosis. Despite its rarity, knowledge of this congenital posterior arch defect of the atlas is important for avoiding diagnostic errors and to provide information on its management. We are therefore reporting a case with this congenital defect discovered as an incidental finding and provide a literature review about this rare anomaly.
Hong Kong Journal of Radiology, 2020
Introduction: Percutaneous transhepatic biliary stone removal is a well-established treatment for... more Introduction: Percutaneous transhepatic biliary stone removal is a well-established treatment for biliary stone disease, as an alternative to the standard endoscopic or surgical approaches. We present our experience in biliary stone removal via the percutaneous transhepatic route, focusing on the techniques, clinical success rate, and complications. Methods: Data on all percutaneous transhepatic biliary stone removals performed at our institution between January 2014 and May 2017 were extracted from patient records. Clinical outcomes, procedure success rate, and complication rate were analysed. Results: In total, 33 procedures were performed in 27 consecutive patients (24 men, 3 women, median age 78.0 years; range, 55-92 years). Reasons for percutaneous transhepatic biliary stone removal included contra-indication to or failure of endoscopic removal (prior gastrectomy or duodenal surgery, n = 19; failed endoscopic retrograde cholangiopancreatography cannulation, n = 3; duodenal stenosis, n = 3; and hepaticojejunostomy stricture, n = 1), and one patient had intrahepatic ductal stones not amenable to endoscopic removal. The overall clinical success rate was 90.9%, with an initial procedure success of complete ductal clearance achieved in 24 cases (72.7%) after the first attempt. Stone removal was unsuccessful in two cases, and incomplete stone removal was present in one case, which were all related to unfavourable biliary anatomy. There were no significant complications (0%) or mortality (0%). The mild complication rate was 15.2% (mild haemobilia, n = 5). Conclusion: Percutaneous transhepatic biliary stone removal is an effective and safe procedure. It is a reliable alternative for patients when endoscopic or surgical approaches are not feasible or unsuccessful.
Hong Kong Journal of Radiology, 2018
Epidermoid cysts in the pelvis are rare and usually associated with local trauma or surgery. They... more Epidermoid cysts in the pelvis are rare and usually associated with local trauma or surgery. They may mimic more threatening lesions and develop complications when they become large. We report a case of epidermoid cyst arising from the ischiorectal fossa in a woman with no history of local trauma or surgery.
Singapore medical journal, May 19, 2016
To identify predictors of outcome and clinical efficacy of emergency pelvic artery embolisation (... more To identify predictors of outcome and clinical efficacy of emergency pelvic artery embolisation (PAE) for primary postpartum haemorrhage (PPH) and to assess post-embolisation fertility of PAE in a regional hospital setting. A 12-year retrospective study of patients undergoing emergency PAE was conducted at a regional acute general hospital. Clinical and procedural parameters, clinical outcome and post-embolisation pregnancy success rates were analysed. There were 47,221 deliveries at our hospital during the study period, among which 33 patients required urgent PAE for primary PPH. Technical success rate for embolisation was 97.0% (n = 32). Clinically adequate haemostasis was achieved by a single embolisation procedure in 24 (72.7%) patients; the remaining eight eventually required surgery to achieve cessation of bleeding. Among the parameters studied, multivariate logistic regression analysis showed that pre-embolisation platelet count (p = 0.036) and maternal age (p = 0.019) were t...
Hong Kong Journal of Radiology, 2016
Objectives: To evaluate the radiation dose reduction to the lens by modifying the scanning plane ... more Objectives: To evaluate the radiation dose reduction to the lens by modifying the scanning plane to exclude the orbit in temporal bone computed tomography (CT). The effect on diagnostic image quality was also evaluated. Methods: Radiation dose reduction was evaluated using a phantom head and calibrated thermoluminescent dosimeters. Image quality was assessed in 34 patients. Two radiology fellows independently reviewed the image and assessed the image quality of 20 temporal bone structures. The image quality was scored on a 4-point scale and analysed with Mann Whitney U test. Results: We demonstrated a 31.4% to 46.1% dose reduction to the lens by excluding the orbit in the scan field. The dose-length products before and after the modification were comparable (p = 0.267). None of the assessed temporal bone structures demonstrated any significant difference in image quality (p > 0.05). Conclusion: Modification of the scanning plane in temporal bone CT can reduce radiation dose exposure to the lens and preserve the diagnostic image quality. This protocol should be considered to minimise the radiation exposure to patients.
Hong Kong Journal of Radiology, 2015
Objective: To investigate the utility of the Appendicitis Computed Tomography (ACT) scoring syste... more Objective: To investigate the utility of the Appendicitis Computed Tomography (ACT) scoring system in the diagnosis of perforated appendicitis and prediction of surgical outcome. Methods: A retrospective study was conducted on 102 subjects who underwent computed tomography (CT) scan and appendectomy for acute appendicitis between May 2011 and January 2012. Images were reviewed for five individual CT signs (appendiceal wall defect, phlegmon, abscess, extraluminal gas, and extraluminal appendicolith) and a score (ACT score) was assigned for each patient based on the number of detectable findings. Correlation of ACT score and individual CT signs with appendiceal perforation and surgical outcome was evaluated statistically. Diagnostic power was assessed using receiving operating characteristic (ROC) curve. Results: A total of 84 subjects were included in the final study after exclusion. ACT score was significantly higher for the perforated group compared with the non-perforated group (2.52 vs. 0.40, p < 0.001) and also higher for the open surgery group than the laparoscopic surgery group (2.78 vs. 0.93, p < 0.001). ACT score was an independent predictor of perforation (odds ratio [OR] = 7.05, p < 0.001), need for open surgery (OR = 2.99, p = 0.002), and operating time (increase of 12.93 minutes, p < 0.001). On ROC curves, ACT score showed a higher discriminating power for both appendiceal perforation (area under the curve [AUC] = 0.939) and need for open surgery (AUC = 0.858) than individual CT signs. An ACT score of 0 was 100% sensitive for excluding appendiceal perforation and open surgery in our study, whereas an ACT score of >3 was diagnostic for perforated appendix. Conclusions: The ACT score is a practical and accurate tool for diagnosis of appendiceal perforation and prediction of surgical outcome.
IEEE Wireless Communications Letters, 2014
ABSTRACT In this letter, we propose an efficient algorithm for the detection of the integer carri... more ABSTRACT In this letter, we propose an efficient algorithm for the detection of the integer carrier frequency offset (CFO) and sector identity used in the LTE cell search. For the conventional LTE cell search, the integer CFO and sector identity are jointly detected by utilizing the primary synchronization signal (PSS). By exploiting the symmetric property of the PSS, the integer CFO can be solely detected without the knowledge of sector identity, and thus, the joint detection of the integer CFO and sector identity is decoupled. Additionally, the proposed sequential integer CFO and sector identity detection (SISID) removes the effect of the channel frequency responses such that the detection accuracy is enhanced. We also design the SISID hardware architecture where the parts of the signals are processed in the polar coordinate so that all the multiplications are realized by additions/subtractions. The simulation results demonstrate that the proposed SISID achieves better detection accuracy than the conventional methods with only one third of the computational complexity.
Hong Kong Journal of Radiology, 2015
Hepatocellular carcinoma is a common malignancy in this locality due to the high prevalence of he... more Hepatocellular carcinoma is a common malignancy in this locality due to the high prevalence of hepatitis B carriers. Radiofrequency ablation is frequently used for treatment of hepatocellular carcinoma. Thermal injury to the diaphragm during radiofrequency ablation for liver tumour is a rare complication. Thermal injury may lead to a defect in the diaphragm and hernia formation. Intestinal obstruction can result from incarceration of the diaphragmatic hernia. We present a patient with intestinal obstruction due to incarcerated diaphragmatic hernia after radiofrequency ablation. The causes, presentation, and imaging findings of this condition are reviewed.
European Journal of Cancer Supplements, 2009
World journal of radiology, Jan 28, 2012
Lipomatous uterine tumors are uncommon benign neoplasms, with incidence ranging from 0.03% to 0.2... more Lipomatous uterine tumors are uncommon benign neoplasms, with incidence ranging from 0.03% to 0.2%. They can generally be subdivided into two types: pure or mixed lipomas. A third group of malignant neoplasm has been proposed, which is liposarcoma; however, this is very rare. In this article, we report three patients having lipomatous uterine tumors, including one uterine lipoma and two uterine lipoleiomyomas. All our patients are postmenopausal women, which is the typical presenting age group. They did not have any symptoms and the tumors were only found incidentally on imaging. However, in some patients, symptoms may uncommonly occur. If symptoms occur, these are similar to those of leiomyoma. We illustrate the imaging features of the tumors in our patients with ultrasound, computed tomography (CT) scan and magnetic resonance imaging (MRI). The tumor typically appears as a well-defined homogenously hyperechoic lesion on ultrasound. It shows fat density on CT scan and signal intens...
Author name used in this publication: 王灿龙Title in Traditional Chinese: 香港書面漢語句法變異: 粵語的移用、文言的保留及其他... more Author name used in this publication: 王灿龙Title in Traditional Chinese: 香港書面漢語句法變異: 粵語的移用、文言的保留及其他Journal title in Traditional Chinese: 語言文字應用2002-2003 > Academic research: refereed > Publication in refereed journalpublished_fina
2006-2007 > Academic research: refereed > Research book or monograph (author
Congenital defects of the posterior arch of the atlas are rare, with a reported prevalence of 0.9... more Congenital defects of the posterior arch of the atlas are rare, with a reported prevalence of 0.95 to 4%. The defects have been classified into five types (A-E), with type A being most common and types B-E being found only in 0.69% of the general population. Although most patients are asymptomatic, some may present with chronic neck pain, headache, Lhermitte’s sign, transient quadriparesis or even acute neurological deficits. The defects may also mimic a Jefferson fracture leading to a wrong diagnosis. Despite its rarity, knowledge of this congenital posterior arch defect of the atlas is important for avoiding diagnostic errors and to provide information on its management. We are therefore reporting a case with this congenital defect discovered as an incidental finding and provide a literature review about this rare anomaly.
Hong Kong Journal of Radiology, 2020
Introduction: Percutaneous transhepatic biliary stone removal is a well-established treatment for... more Introduction: Percutaneous transhepatic biliary stone removal is a well-established treatment for biliary stone disease, as an alternative to the standard endoscopic or surgical approaches. We present our experience in biliary stone removal via the percutaneous transhepatic route, focusing on the techniques, clinical success rate, and complications. Methods: Data on all percutaneous transhepatic biliary stone removals performed at our institution between January 2014 and May 2017 were extracted from patient records. Clinical outcomes, procedure success rate, and complication rate were analysed. Results: In total, 33 procedures were performed in 27 consecutive patients (24 men, 3 women, median age 78.0 years; range, 55-92 years). Reasons for percutaneous transhepatic biliary stone removal included contra-indication to or failure of endoscopic removal (prior gastrectomy or duodenal surgery, n = 19; failed endoscopic retrograde cholangiopancreatography cannulation, n = 3; duodenal stenosis, n = 3; and hepaticojejunostomy stricture, n = 1), and one patient had intrahepatic ductal stones not amenable to endoscopic removal. The overall clinical success rate was 90.9%, with an initial procedure success of complete ductal clearance achieved in 24 cases (72.7%) after the first attempt. Stone removal was unsuccessful in two cases, and incomplete stone removal was present in one case, which were all related to unfavourable biliary anatomy. There were no significant complications (0%) or mortality (0%). The mild complication rate was 15.2% (mild haemobilia, n = 5). Conclusion: Percutaneous transhepatic biliary stone removal is an effective and safe procedure. It is a reliable alternative for patients when endoscopic or surgical approaches are not feasible or unsuccessful.
Hong Kong Journal of Radiology, 2018
Epidermoid cysts in the pelvis are rare and usually associated with local trauma or surgery. They... more Epidermoid cysts in the pelvis are rare and usually associated with local trauma or surgery. They may mimic more threatening lesions and develop complications when they become large. We report a case of epidermoid cyst arising from the ischiorectal fossa in a woman with no history of local trauma or surgery.
Singapore medical journal, May 19, 2016
To identify predictors of outcome and clinical efficacy of emergency pelvic artery embolisation (... more To identify predictors of outcome and clinical efficacy of emergency pelvic artery embolisation (PAE) for primary postpartum haemorrhage (PPH) and to assess post-embolisation fertility of PAE in a regional hospital setting. A 12-year retrospective study of patients undergoing emergency PAE was conducted at a regional acute general hospital. Clinical and procedural parameters, clinical outcome and post-embolisation pregnancy success rates were analysed. There were 47,221 deliveries at our hospital during the study period, among which 33 patients required urgent PAE for primary PPH. Technical success rate for embolisation was 97.0% (n = 32). Clinically adequate haemostasis was achieved by a single embolisation procedure in 24 (72.7%) patients; the remaining eight eventually required surgery to achieve cessation of bleeding. Among the parameters studied, multivariate logistic regression analysis showed that pre-embolisation platelet count (p = 0.036) and maternal age (p = 0.019) were t...
Hong Kong Journal of Radiology, 2016
Objectives: To evaluate the radiation dose reduction to the lens by modifying the scanning plane ... more Objectives: To evaluate the radiation dose reduction to the lens by modifying the scanning plane to exclude the orbit in temporal bone computed tomography (CT). The effect on diagnostic image quality was also evaluated. Methods: Radiation dose reduction was evaluated using a phantom head and calibrated thermoluminescent dosimeters. Image quality was assessed in 34 patients. Two radiology fellows independently reviewed the image and assessed the image quality of 20 temporal bone structures. The image quality was scored on a 4-point scale and analysed with Mann Whitney U test. Results: We demonstrated a 31.4% to 46.1% dose reduction to the lens by excluding the orbit in the scan field. The dose-length products before and after the modification were comparable (p = 0.267). None of the assessed temporal bone structures demonstrated any significant difference in image quality (p > 0.05). Conclusion: Modification of the scanning plane in temporal bone CT can reduce radiation dose exposure to the lens and preserve the diagnostic image quality. This protocol should be considered to minimise the radiation exposure to patients.
Hong Kong Journal of Radiology, 2015
Objective: To investigate the utility of the Appendicitis Computed Tomography (ACT) scoring syste... more Objective: To investigate the utility of the Appendicitis Computed Tomography (ACT) scoring system in the diagnosis of perforated appendicitis and prediction of surgical outcome. Methods: A retrospective study was conducted on 102 subjects who underwent computed tomography (CT) scan and appendectomy for acute appendicitis between May 2011 and January 2012. Images were reviewed for five individual CT signs (appendiceal wall defect, phlegmon, abscess, extraluminal gas, and extraluminal appendicolith) and a score (ACT score) was assigned for each patient based on the number of detectable findings. Correlation of ACT score and individual CT signs with appendiceal perforation and surgical outcome was evaluated statistically. Diagnostic power was assessed using receiving operating characteristic (ROC) curve. Results: A total of 84 subjects were included in the final study after exclusion. ACT score was significantly higher for the perforated group compared with the non-perforated group (2.52 vs. 0.40, p < 0.001) and also higher for the open surgery group than the laparoscopic surgery group (2.78 vs. 0.93, p < 0.001). ACT score was an independent predictor of perforation (odds ratio [OR] = 7.05, p < 0.001), need for open surgery (OR = 2.99, p = 0.002), and operating time (increase of 12.93 minutes, p < 0.001). On ROC curves, ACT score showed a higher discriminating power for both appendiceal perforation (area under the curve [AUC] = 0.939) and need for open surgery (AUC = 0.858) than individual CT signs. An ACT score of 0 was 100% sensitive for excluding appendiceal perforation and open surgery in our study, whereas an ACT score of >3 was diagnostic for perforated appendix. Conclusions: The ACT score is a practical and accurate tool for diagnosis of appendiceal perforation and prediction of surgical outcome.
IEEE Wireless Communications Letters, 2014
ABSTRACT In this letter, we propose an efficient algorithm for the detection of the integer carri... more ABSTRACT In this letter, we propose an efficient algorithm for the detection of the integer carrier frequency offset (CFO) and sector identity used in the LTE cell search. For the conventional LTE cell search, the integer CFO and sector identity are jointly detected by utilizing the primary synchronization signal (PSS). By exploiting the symmetric property of the PSS, the integer CFO can be solely detected without the knowledge of sector identity, and thus, the joint detection of the integer CFO and sector identity is decoupled. Additionally, the proposed sequential integer CFO and sector identity detection (SISID) removes the effect of the channel frequency responses such that the detection accuracy is enhanced. We also design the SISID hardware architecture where the parts of the signals are processed in the polar coordinate so that all the multiplications are realized by additions/subtractions. The simulation results demonstrate that the proposed SISID achieves better detection accuracy than the conventional methods with only one third of the computational complexity.
Hong Kong Journal of Radiology, 2015
Hepatocellular carcinoma is a common malignancy in this locality due to the high prevalence of he... more Hepatocellular carcinoma is a common malignancy in this locality due to the high prevalence of hepatitis B carriers. Radiofrequency ablation is frequently used for treatment of hepatocellular carcinoma. Thermal injury to the diaphragm during radiofrequency ablation for liver tumour is a rare complication. Thermal injury may lead to a defect in the diaphragm and hernia formation. Intestinal obstruction can result from incarceration of the diaphragmatic hernia. We present a patient with intestinal obstruction due to incarcerated diaphragmatic hernia after radiofrequency ablation. The causes, presentation, and imaging findings of this condition are reviewed.
European Journal of Cancer Supplements, 2009
World journal of radiology, Jan 28, 2012
Lipomatous uterine tumors are uncommon benign neoplasms, with incidence ranging from 0.03% to 0.2... more Lipomatous uterine tumors are uncommon benign neoplasms, with incidence ranging from 0.03% to 0.2%. They can generally be subdivided into two types: pure or mixed lipomas. A third group of malignant neoplasm has been proposed, which is liposarcoma; however, this is very rare. In this article, we report three patients having lipomatous uterine tumors, including one uterine lipoma and two uterine lipoleiomyomas. All our patients are postmenopausal women, which is the typical presenting age group. They did not have any symptoms and the tumors were only found incidentally on imaging. However, in some patients, symptoms may uncommonly occur. If symptoms occur, these are similar to those of leiomyoma. We illustrate the imaging features of the tumors in our patients with ultrasound, computed tomography (CT) scan and magnetic resonance imaging (MRI). The tumor typically appears as a well-defined homogenously hyperechoic lesion on ultrasound. It shows fat density on CT scan and signal intens...