Biomedical subjects

Alex W H Ng

Publications and source records attributed to Alex W H Ng.

4 recordsLinked to original sources

PubMed2006

Thin-Section CT 12 Months After the Diagnosis of Severe Acute Respiratory Syndrome in Pediatric Patients.

OBJECTIVE: The objective of our study was to report the thin-section CT findings 12 months after the diagnosis of severe acute respiratory syndrome (SARS) in pediatric patients who had recovered clinically but had persistent abnormal CT findings 6 months after the diagnosis. The clinical data for these patients were correlated to identify risk factors that might increase the likelihood of the development of CT abnormalities. SUBJECTS AND METHODS: The study involved an extended 12-month thin-section CT follow-up of 16 of 47 pediatrics patients with SARS coronavirus-associated pneumonia proven serologically (21 girls and 26 boys; age range, 1.5-17 years; median age, 13.6 years). Patients' clinical information, the extent of radiographic opacification during the acute phase of illness, and conventional pulmonary function test results on follow-up were obtained for correlation. The clinical parameters were compared with other pediatric SARS patients who had normal CT findings at the 6-month follow-up. RESULTS: Fifteen patients still had abnormal CT findings 12 months after diagnosis, all of whom were older than 10 years (age range, 10-17 years). In seven patients with previous residual ground-glass opacification at the 6-month follow-up, two showed persistent changes and three had a reticular pattern in the area of the previously detected abnormality, whereas two showed complete resolution. The extent of air trapping remained similar to that at the 6-month follow-up in nine of 11 patients while two showed a slight increase in the same segments. Parenchymal scars remained unchanged from the 6- to 12-month follow-up in all six patients with that finding. None of our patients showed any evidence of bronchiectasis or bronchial wall thickening. Lymphopenia (p = 0.03), extent of radiographic opacification at acute illness (p = 0.047), and duration of use of ribavirin (p = 0.03) were significant risk factors in predicting whether abnormal CT features persisted 12 months after diagnosis. CONCLUSION: We found that 32% of the children (15/47) affected with SARS showed thin-section CT abnormalities up to 12 months after diagnosis despite clinical remission and unremarkable pulmonary function assessment. Persistent CT abnormalities are more likely to develop in patients who are older and who present with more severe disease. The CT changes in children with SARS are, however, minor.

Adolescent↗

PubMed2005

Chest radiograph scores as potential prognostic indicators in severe acute respiratory syndrome (SARS).

OBJECTIVE: We analyzed serial chest radiographic scores for lung opacification in patients with severe acute respiratory syndrome (SARS) for temporal changes and differences between fatal and discharged cases. We sought to establish the earliest radiographic scores sensitive as potential prognostic indicators of fatal outcomes. MATERIALS AND METHODS: Chest radiographs that had been obtained from presentation until the death or discharge of 313 patients with SARS were scored on the basis of the percentage area and location of lung opacification. Profile analysis and univariable logistic regression were performed on these radiographic scores. RESULTS: Despite the increased mortality risks of advanced age and male sex, no significant difference was seen in the percentage area of opacification (AO%) between the sexes in either the group of patients with fatal outcomes or the group of patients who were discharged. No difference existed between age groups (< 65 years vs >/= 65 years), except for the radiograph showing the peak lung opacification in the deceased group in which the lungs of older patients had less opacification than those of younger patients. The radiographic scores obtained by day 7 were the earliest ones with good performance in prognostic prediction. The model showed good discriminatory performance, indicated by high C-indexes for receiver operator characteristic curves (0.86 for AO% and 0.90 for the number of opacified zones). The predicted proportion of patients with fatal outcomes showed high agreement with percentage of patients who died (goodness-of-fit statistic p = 0.18 for AO%, 0.73 for the number of opacified zones). By day 7, crude odds ratio of death was 1.73 per 5% of AO% (p < 0.0001) or 2.93 per lung zone opacified (p < 0.0001). CONCLUSION: Chest radiographic scores (percentage of lung or the number of zones opacified) by day 7 could be used as fatal prognostic indicators.

Adolescent↗

PubMed2004

Primitive neuroectodermal kidney tumour.

Renal primitive neuroectodermal tumour (PNET) is a rare malignant tumour of paediatric patients. We describe the important imaging findings, including the ultrasound, CT and MRI of a case of renal PNET in a teenager. To our knowledge, some findings have not been described previously. Some features that have been considered as characteristic are not present in our case, and it is, to our knowledge, the first documented case with such extensive tumour thrombus. We also demonstrate the importance of including PNET as a differential diagnosis because combined chemotherapy is thought to be the best first-line treatment in most cases. Histological diagnosis can be determined by a minimally invasive procedure instead of laparotomy or open biopsy.

Adolescent↗

PubMedDate not supplied

Extensive paraspinal abscess complicating tuberculous spondylitis in an adolescent with Pott kyphosis.

A 16-year-old girl who suffered from untreated tuberculosis spondylitis since childhood presented with marked Potts kyphotic deformity in adolescence. She had increasing shortness of breath and was admitted for investigation of right pleural effusion. On radiological examination, she was found to have extensive paraspinal abscesses, with the largest collection trapped within the kyphotic angulation in the thoracic region. The latter could only be appreciated with magnetic resonance (MR) imaging and had been overlooked in the initial computed tomography (CT).

Abscess↗