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Biomedical subjects

H F Wong

Publications and source records attributed to H F Wong.

At least 37 records · Page 2Linked to original sources
PubMed1997

CT angiography of intracranial aneurysms: advantages and pitfalls.

OBJECTIVE: To determine the clinical usefulness of computed tomography (CT) angiography in the evaluation of cerebral aneurysms. MATERIALS AND METHODS: From October 1994 through April 1996, 26 patients with 30 surgical proven intracranial aneurysms underwent both CT angiography and catheter cerebral angiography. The findings of the two methods were reviewed independently and then compared with each other. RESULTS: Comparing with catheter angiography, CT angiography was superior in demonstrating the aneurysmal neck in seven aneurysms but was inferior in one. The thrombosed part and calcification of aneurysms were clearly demonstrated on CT angiograms. CT angiography also aided in differentiating tight vascular loops from aneurysms. On CT angiograms, one posterior communicating arterial aneurysm was overlooked and another anterior choroidal artery aneurysm was misinterpreted as a posterior communicating artery aneurysm. Of note were two patients in whom the infundibulum of the orbitofrontal artery was misinterpreted as the anterior communicating artery aneurysm. CONCLUSION: CT angiography can compliment conventional catheter angiography for its better demonstration of the 3-dimensional anatomy. It can provide surgical information about the neck, calcification and thrombosed part of an aneurysm and its relation to adjacent structures. However, caution is advocated because CT angiography may fail to demonstrate small but important vessels such as posterior communicating, anterior choroidal and orbitofrontal arteries. Recognition of the limitations of CT angiography is important in minimizing interpretation errors.

Adult↗
PubMed1997

CT findings of bronchial transection.

A case of right bronchial rupture demonstrated by computed tomography (CT) is reported. Chest radiographs of a 55-year-old man who sustained blunt chest trauma showed bilateral pneumomediastinum, hydropneumothorax, and subcutaneous emphysema with fracture of the left 3rd and 4th ribs. CT showed wall defect over the right main bronchus with the air in airway contiguous to that in the mediastinum. Bronchoscopy and thoracostomy confirmed the CT findings and the patient was treated by bronchorrhaphy with end-to-end anastomosis. The airway should be meticulously evaluated in cases of mediastinal and subcutaneous emphysema, especially after trauma.

Bronchi↗
PubMed1997

Factors related to detection of blood flow by color Doppler ultrasonography in intussusception.

Color Doppler ultrasonography was performed in 125 patients with 134 intussusceptions. Color flow was present in 121 cases of intussusception (group A) and was absent in 13 cases (group B). Young age and duration of symptoms greater than 48 hr were significantly related to the nonvisualization of blood flow detected by color Doppler sonography (P < 0.05). The successful rate of air reduction was significantly higher in group A than in group B (109 of 121 versus 4 of 13). Color Doppler ultrasonography is useful to predict the reducibility of an intussuscepted intestine. The nonvisualization of blood flow by this method is not a contraindication for air reduction.

Adolescent↗
PubMed1997

Three-dimensional magnetic resonance cholangiopancreatography for evaluation of obstructive jaundice.

The purpose of this study was to assess the diagnostic value of magnetic resonance cholangiopancreatography (MRCP) in studying the anatomy, sites, and causes of obstructive jaundice. From September 1994 to May 1996 three-dimensional MRCP was performed on 31 patients with abdominal pain and obstructive jaundice with a fast spin-echo T2-weighted pulse sequence. The images were reconstructed using maximal intensity projection, AVERAGE and SURFACE algorithm processing techniques at a graphics workstation. All the reconstructed images were compared with those obtained using conventional cholangiographic techniques, such as endoscopic retrograde cholangiopancreatography, percutaneous transhepatic cholangiography and drainage, and intraoperative cholangiography. The patients' diagnoses included choledochal cyst (13), cholangiocarcinoma (five), choledocholithiasis (four), pancreatic head carcinoma (three), rhabdomyosarcoma (one), papillary Vater carcinoma (one), recurrent gastric carcinoma (one), ascaris (one), and biliary atresia (two). Extrahepatic biliary dilatation was present in all 13 patients with choledochal cyst; the pancreatic ducts and their entrance level to the common bile duct were observed in eight of these patients. The level of obstruction in patients with cholangiocarcinoma was well documented but the biliary tract of one patient with biliary atresia was not identified by MRCP. In one patient with biliary rhabdomyosarcoma, MRCP clearly delineated the extrabiliary extension of the tumor. In a patient with ascaris in the common bile duct an increase in signal intensity inside the digestive tract of the worm denoted fluid in its gut. Lithiasis was shown in all of the four patients with choledocholithiasis. Thus, MRCP is a useful tool in the assessment of biliary tract obstruction and its causes, and is a valuable addition to ultrasonography.

Adolescent↗
PubMed1996

Tuberculoma en plaque: CT.

A 35-year-old woman presented with a 6-month history of intermittent headaches, vomiting and dizziness. CT showed a plaque-like mass with tiny calcifications along the surface of the left frontal lobe. The mass exhibited heterogeneous enhancement with a few low-density foci. Underlying sulcal obliteration and enhancement and white matter oedema were also noted. Histopathological examination of excised material was consistent with tuberculoma. Recognition of this unusual presentation of intracranial tuberculoma may facilitate appropriate diagnosis and management.

Adult↗
PubMed1996

Primary cardiac chondrosarcoma.

A case of primary cardiac chondrosarcoma in a 41-year-old woman who presented with cardiac tamponade and cardiac intracavitary obstruction is described. The tumor originated from the right atrium and invaded the adjacent right ventricular wall and interatrial septum. Primary cardiac chondrosarcoma is extremely rare, and its clinical, computed tomographic, echocardiographic, and magnetic resonance imaging findings are described.

Adult↗
PubMed1996

The effects of a self-educating blood component request form and enforcements of transfusion guidelines on FFP and platelet usage. Queen Mary Hospital, Hong Kong. British Committee for Standards in Hematology (BCSH).

Despite establishment of transfusion guidelines and feedback intervention, FFP and platelet transfusion were still inappropriate in many clinical situations at our hospital. Many physicians never read or referred to the guidelines when they were ordering FFP and platelet transfusion. A new blood component request form with the guidelines printed on it was designed to facilitate physician education and enforcement of these transfusion guidelines. The form was well accepted by junior house staff and inappropriate transfusion was significantly reduced.

Attitude of Health Personnel↗
PubMed1996

A novel system for providing compatible blood to patients during surgery: "self-service" electronic blood banking by nursing staff.

BACKGROUND: A good blood bank must be able to provide compatible blood units promptly to operating room patients with minimal wastage. A "self-service" by nursing staff blood banking system that is safe, efficient, and well-accepted has been developed. STUDY DESIGN AND METHODS: Specific blood units are no longer assigned to surgical patients who have a negative pretransfusion antibody screen, irrespective of the type of surgery. A computer-generated list of the serial numbers of all group-identical blood units currently in the blood bank inventory is provided for each patient. The units themselves are not labeled with a patient's name. The group O list will be provided for group O patients, the group A list for group A patients, and so forth. Should the patient require transfusion during surgery, the operating room nurses go to the refrigerator, remove any group-identical unit, and check the serial number of the unit against the serial numbers on the patient's list. If the serial number is on that list, the blood bank will accept responsibility for compatibility. The system was implemented in 1995. RESULTS: Since implementation, a total of 2154 patients have undergone operations at this hospital. Thirty-two patients received more than 10 units of red cells each. There were no transfusion errors. The crossmatch-to-transfusion ratio was reduced from 1.67 to 1.12. Turnaround time for supplying additional or urgent units to patients in operating room was shortened from 33 to 2.5 minutes. There was no incidence of a blood unit's serial number not being on the list. Work by nurses and technical staff was reduced by nearly 50 percent. CONCLUSION: The "self-service" (by nursing staff) blood banking system described is safe and efficient. It saves staff time and can be easily set up.

Blood Banks↗
PubMed1996

The impact of a gel system on routine work in a general hospital blood bank.

The gel system has been reported to be more sensitive and specific than the conventional tube indirect antiglobulin test (IAT) for antibody screening. However, a major concern about the gel system is its cost. A cost analysis study was therefore conducted at our hospital. The gel system costs more than the conventional tube IAT per test; however, the total staff and reagent costs per year were about equal, because of staff savings. Workload and cost per patient requiring blood were reduced using the gel system.

Journal Article↗
PubMed1996

Posterior bow and vanishing line signs in diagnosis of burst fractures of the spine on plain radiographs.

It is not uncommon to misdiagnose a burst fracture as a wedge compression fracture initially on plain film, resulting in a late progressive deformity and neurologic damage. The purpose of this study was to analyze the sensitivity, specificity and positive predictive value of plain radiographs in the diagnosis of thoracic and lumbar burst fractures using the posterior bow (PB) and vanishing line (VL) signs. Seven independent examiners, comprising three chief orthopedic residents, two radiologic third-year residents and two emergency attending physicians (orthopedists), randomly reviewed 26 sets of admission anteroposterior and lateral thoracolumbar spine radiographs taken in association with back injuries. They were asked to decide whether patients had a burst or a wedge compression fracture. All patients had computed tomography (CT) scans for diagnostic confirmation. The overall initial sensitivity using discriminant analysis in the diagnosis of burst fractures was 80%. This increased to 90% after the examiners were requested to use the PB and VL signs. The specificity decreased slightly from 75% to 71%, while the positive predictive value remained at 88%. Overdiagnosis of wedge compression fractures as burst fractures occurred, especially when the quality of the films was not ideal. We conclude that, with careful reading, the PB and VL signs help in identifying burst fractures on the initial plain film evaluation.

Adult↗
PubMed1995

Congenital extracranial meningioma.

The authors report a case of congenital meningioma in a newborn. This tumour is extremely rare and only six cases have been reported in the literature. Those reported cases were mainly intracranial. This is the first case of a neonatal extracranial meningioma that was evaluated preoperatively by computed tomography and magnetic resonance imaging.

Humans↗
PubMed1995

Pneumatic reduction of intussusception in children.

Over the past decade, pneumatic reduction has been increasingly accepted as the treatment of choice for pediatric intussusception. However the effectiveness of air compared with the more traditional barium reduction of intussusception continues to be a source of concern and debate. From August 1993 to November 1994, pneumatic reduction was used to treat 75 episodes in 73 patients with proven intussusception at Chang Gung Memorial Hospital, Taoyuan. Two patients underwent air reduction twice because of recurrence following an initial successful reduction. The recurrence rate was 3%. Successful reduction was achieved in 65/75 (87%) episodes. None of the patients experienced any complications following the procedure. In two of the 10 patients in whom reduction failed, one was subsequently found to have a Meckel's diverticulum and the other a duplication cyst as a leading point. This prospective study indicates that air enema is a safe and effective form of treatment for intussusception in infants and children. Pneumatic reduction should be the treatment of choice in the initial management of intussusception.

Child↗
PubMed1994

Endoscopic injection sclerotherapy for esophageal variceal bleeding in children with extrahepatic portal vein obstruction.

From October 1989 to March 1994, 30 endoscopic injection sclerotherapies were performed in four consecutive female children who had extrahepatic portal vein obstruction complicated with esophageal variceal bleeding. Eradication of varices was achieved in three patients. However, bleeding occurred again in two of these patients due to esophageal varix recurrence. One patient, who discontinued sclerotherapy because of hemoptysis during treatment, also had 12 episodes of esophageal bleeding which were controlled by shunt therapy. In addition to hemoptysis, other complications were bleeding during sclerotherapy and fever. The sclerotherapy complication rate in this study was 17%. Our results suggest that endoscopic injection sclerotherapy is an effective and safe method for the prevention of variceal bleeding in children with extrahepatic portal vein obstruction. Long-term regular endoscopy follow-up and even repeated sclerotherapy are needed to prevent bleeding due to recurrence of esophageal varices.

Child↗
PubMed1994

Intussusception in infants and children: risk factors leading to surgical reduction.

Intussusception is commonly the etiology of intestinal obstruction in infants and children. To investigate demographic data, clinicopathologic features and therapeutic prognosis of patients with intussusception, we reviewed 361 intussusceptions in 333 patients over an 11-year period. Most patients were below two years of age and there was a male preponderance of 1.6:1. There was no seasonal difference between the number of cases. The clinical triad of vomiting, abdominal colicky pain and bloody stools was manifested in only one-third of our patients. Secondary intussusception contributed to 6.6% of cases and Meckel's diverticulum was the most common pathologic cause. Positive findings were recorded in 82% of 67 patients undergoing sonographic examination. Intussusception of the ileo-colic type was most frequently encountered. Most patients (79%) were diagnosed within 48 hours and almost all cases underwent primary barium enema reduction. The success rate was 45%. Laparotomy was performed in 207 patients (57%) refractory to enema reduction or with critical illness, and intestinal resection was required in 28 (14%). Long-standing duration of illness (> 24 hours), positive clinical triad, positive pathologic lead point, and radiologic finding of bowel obstruction were identified as risk factors leading patients to surgical reduction (p < 0.001). Postoperative complications and recurrent intussusception developed in some patients, and the overall mortality was 0.6%. The clinical characteristics of intussusception in children generally remained unchanged as compared to previous reports. Early identification of patients with risk factors for surgical treatment is important to decrease the need for intestinal resection.

Adolescent↗
PubMed1994

Mesenteric panniculitis: report of two cases.

Mesenteric panniculitis is a rare inflammatory process of the mesenteric fat with unknown etiology. We report two pathologically proven cases of mesenteric panniculitis. Both patients presented with abdominal pain and palpable masses. In one patient, computed tomography (CT) demonstrated a well-defined heterogenous mass containing fat density at the mesocolon. In the other patient, CT showed a fatty mass encompassing mesenteric vessels at the root of the mesentery. Although the definite diagnosis of mesenteric panniculitis depends on histopathology, recognition of CT features is helpful in the diagnosis and avoids unnecessary extensive operation.

Adult↗
PubMed1993

Retroperitoneal Castleman's disease: report of two cases.

Castleman's disease (angiofollicular lymph node hyperplasia) is a rare benign disorder characterized by hypervascular lymphoid hyperplasia. It usually manifests as an asymptomatic, solitary mediastinal tumor, and seldom presents as an isolated retroperitoneal mass. We report two cases of histologically proven Castleman's disease occurring in the retroperitoneum. Their computed tomographic and angiographic features are presented, and the characteristics of this condition are described. Recognition of Castleman's disease in the retroperitoneal area is helpful in avoiding massive intraoperative hemorrhage and an unnecessarily extensive operation.

Adolescent↗