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W W M Lam

Publications and source records attributed to W W M Lam.

At least 19 recordsLinked to original sources
PubMed2006

The role of immunohistochemistry for smooth-muscle actin, p63, CD10 and cytokeratin 14 in the differential diagnosis of papillary lesions of the breast.

BACKGROUND: Histological differentiation of mammary papillary lesions can be difficult. The evaluation of myoepithelial cells can be helpful, with benign papilloma showing a continuous myoepithelial cell layer, which becomes attenuated or absent in malignant papillary lesions. METHODS: A large series of 100 papillomas (28 papillomas with florid epithelial hyperplasia) and 68 papillary carcinomas (9 invasive, 44 in situ, and 15 ductal carcinomas in situ (DCIS) involving papillomas) of the breast were stained for myoepithelial cells by immunohistochemistry using antibodies to smooth-muscle actin (SMA), p63, CD10 and cytokeratin (CK) 14. RESULTS: In the papillomas, using these four antibodies, myoepithelial cells were positive in 88%, 99%, 91% and 95% of cases, respectively, with SMA showing marked stromal component cell staining and CD10 showing epithelial and stromal staining. CK14 also showed epithelial staining in 71% of papillomas and 96% of papillomas with florid epithelial hyperplasia. In the papillary carcinomas, 36 (53%) cases showed staining of myoepithelial cells that were scattered, discontinuous and diminished in number and the remaining 32 (47%) cases did not show myoepithelial cells. Invasive papillary carcinoma has the lowest proportion (33%) with myoepithelial cells, and DCIS involving papillomas had the highest proportion (87%). CONCLUSIONS: p63 had the highest sensitivity and did not cross-react with stromal cells and only rarely with epithelial cells. CK14 has the added ability to distinguish between florid epithelial hyperplasia involving papilloma and DCIS involving papillomas. CK14 and p63 may be used as an adjunct in assessing difficult papillary lesions of the breast.

Actins↗
PubMed2006

Curve correction effect of rigid spinal orthosis in different recumbent positions in adolescent idiopathic scoliosis (AIS): a pilot MRI study.

In this pilot cross-sectional study, the effectiveness of rigid spinal orthoses in the correction of spinal curvature of 14 patients with moderate adolescent idiopathic scoliosis (AIS) at different recumbent positions (supine, prone, right and left decubitus) was investigated. Using magnetic resonance (MR) imaging and multi-planar reconstruction technique, evaluation of the scoliotic spine in the coronal, sagittal and axial planes and the effect of spinal orthosis on AIS at different recumbent positions was studied. There was significant reduction of coronal Cobb's angle (p < 0.05) with bracing at all four recumbent positions and the maximal reduction was found in the prone position (18% reduction). The sagittal Cobb's angle was only significantly reduced at the supine position while the axial rotation did not change significantly in all positions.

Adolescent↗
PubMed2006

Apolipoprotein E epsilon4 allele is associated with the volume of white matter changes in patients with lacunar infarcts.

The relationship between the apolipoprotein E (APOE) exon 4 polymorphism and white matter changes (WMC) in elderly subjects or patients with Alzheimer's disease is controversial. To investigate this polymorphism in relation to WMC in patients with lacunar infarcts, we prospectively observed 67 patients with acute lacunar infarct and 134 age- and sex-matched controls. Genotypes were determined using a nested polymerase chain reaction. WMC were measured quantitatively and were divided into two groups, severe and mild, with the mean volume of WMC as the cut point. Twenty-two patients (33%) had severe WMC. There was a significant difference in the distribution of APOE epsilon2, epsilon3, and epsilon4 alleles between severe and mild WMC groups (P = 0.002). The frequency of epsilon4 alleles was higher in patients with severe WMC than in those with mild WMC (25% vs. 7%, P = 0.003). These results suggest that APOE epsilon4 may exacerbate WMC in patients with lacunar infarcts. Further studies are required to confirm this finding.

Aged↗
PubMed2006

Role of radiologic features in the management of papillary lesions of the breast.

OBJECTIVE: The purpose of our study was to assess the role of imaging and core biopsy in the management of patients with papillary lesions of the breast. MATERIALS AND METHODS: Clinical records and mammographic and sonographic findings of 40 women with papillary lesions in the breast were retrieved. The imaging features and cytologic findings were correlated with histologic findings. RESULTS: Fifty-six papillary lesions in 40 patients underwent either mastectomy, segmental duct resection, or excision biopsy. There were three papillary carcinomas, 13 papillaryal lesions with carcinoma in situ, one atypical papilloma, four sclerosed papillomata, and 35 papillomata. Of these lesions, 37.5% (21/56) and 82.1% (46/56) could be detected on mammography and sonography, respectively. Galactography and dilated ducts helped to suggest the papillary nature of the lesions. However, mammography and sonography were not able to predict malignancy (sensitivity, 69% and 56%, respectively; specificity, 25% and 90%; positive predictive value [PPV], 60% and 75%; and negative predictive value [NPV], 33% and 90%). Combined interpretation of mammography and sonography gave a sensitivity of 61%, specificity of 33%, PPV of 85%, and NPV of 13%. Fine-needle aspiration gave a sensitivity of 44%, specificity of 68%, PPV of 31%, and NPV of 79%, whereas core biopsy gave a sensitivity of 82%, specificity of 100%, PPV of 100%, and NPV of 83% in the diagnosis of malignancy. CONCLUSION: Radiologic features are not sufficiently sensitive or specific to differentiate benign from malignant papillary lesions. Fine-needle aspiration and core biopsy have pitfalls, and the need for surgical excision of all papillary lesions should be revisited.

Adult↗
PubMed2006

Intravenous leiomyomatosis: computed tomography diagnosis.

Intravenous leiomyomatosis is a rare neoplastic condition characterised by nodular masses of histologically benign smooth muscle growing within veins. In most cases, the disease is confined to the pelvic veins, but involvement may extend to the inferior vena cava and right heart chamber. We report the computed tomography features of a woman who developed extensive intravenous leiomyomatosis and lung metastases, and presented with acute-onset lower limb swelling.

Diagnosis, Differential↗
PubMed2005

Determinants of prestroke cognitive impairment in stroke associated with small vessel disease.

Understanding the determinants of prestroke cognitive impairment (PCI) in stroke associated with small vessel disease (SVD) may shed light on how to prevent further cognitive deterioration after stroke. We administered the Informant Questionnaire on Cognitive Decline (IQCODE) to close informants of 78 consecutive stroke patients who had SVD. PCI, as defined by an average score of IQCODE > or =3.4 was found in 19 (24%) patients. Regression analyses were performed on the following risk factors for PCI: age, years of education, gender, previous stroke, volume of white matter changes, measures of silent lacunes, cerebral atrophy index, medial temporal lobe atrophy and frontal lobe atrophy. Multivariate regression analyses revealed that only cerebral atrophy index (OR 1.5, CI 1.2-1.9, p < 0.001) predicted PCI among patients with SVD.

Aged↗
PubMed2005

Cerebral blood flow (CBF)-directed management of ventilated head-injured patients.

OBJECTIVE: Ischaemic brain damage has been shown to be an important contributing factor causing head injury fatality. Maintenance of an adequate cerebral perfusion pressure is difficult in patients with elevated intracranial pressure (ICP) and deranged cerebral vasoreactivity. Thirty-five cases of ventilated moderate-to-severe head-injured patients were prospectively studied, correlating their cerebral haemodynamic abnormalities, neurochemical disturbances (using microdialysis methodology) and clinical outcome. METHODS: Cerebral haemodynamic abnormalities were defined and classified by transcranial Doppler ultrasonography (TCD) and stable xenon-CT cerebral blood flow measurements (XeCT) into their status of CO2 reactivity, pressure autoregulation, hyperaemia or non-hyperaemia. Two-hour episodes of these abnormalities with and without haemodynamic intervention were followed in their changes in ICP, CPP, intracerebral metabolites and finally their clinical outcome. RESULTS: Loss of CO2 reactivity was associated with a significantly higher ICP, increasing intracerebral metabolites (lactate, glutamate and glycerol) and invariably a fatal outcome. Impaired pressure autoregulation was also associated with an elevated ICP, but no significant difference in intracerebral metabolites and incidence of favourable clinical outcome. Patients with intact CO2 reactivity and impaired pressure autoregulation were treated with an elevated CPP in 32 episodes, resulting in a significant reduction in ICP, intracerebral glutamate and glycerol and non-survival. In patients with intact CO2 reactivity and impaired pressure autoregulation, eleven episodes of hyperaemia were identified by XeCT. A modest 20%, blood pressure reduction resulted in a trend towards a reduction of ICP, intracerebral glutamate and glycerol and non-survival. CONCLUSIONS: The need for haemodynamic intervention in this group of ventilated patients with moderate-to-severe head inury can be made logical when these abnormalities are identified daily. The success of management was reflected by a stable or improved ICP, CPP, intracerebral metabolic deranagement and survival.

Brain Ischemia↗
PubMed2005

Early computed tomography features in extensive middle cerebral artery territory infarct: prediction of survival.

BACKGROUND: To assess the predictive value of prognosis of different computed tomography (CT) features and National Institutes of Health Stroke Scale score (NIHSS) in acute extensive middle cerebral artery (MCA) infarct. METHODS: Fifty five patients with acute extensive MCA infarct had the CT performed within 24 hours of the onset of symptoms. A total of 11 CT features were analysed. The age distribution, presence of risk factors, presence of individual CT feature, the total CT score, and the NIHSS were correlated with the 30 day mortality. RESULTS: Single explanatory variable analysis showed NIHSS, presence of midline shift, midline shift of more than 1 cm, extent of infarct, presence of hydrocephalus, effacement of subarachnoid space/cella media, attenuation of corticomedullary differentiation, and total CT score were associated with the 30 day mortality. Both extent of infarct >67% and attenuation of corticomedullary differentiation gave a sensitivity and specificity of 93% and 95%, respectively, for the prediction of survival. Logistic regression analysis showed that the extent of infarct and NIHSS were the only independent predictors. CONCLUSIONS: CT features and admission NIHSS are important parameters for prediction of survival in extensive MCA infarct.

Aged↗
PubMed2005

Neuroimaging determinants of cognitive performances in stroke associated with small vessel disease.

BACKGROUND AND PURPOSE: Controversies still exist as to the neuroimaging determinants of cognitive impairment in cerebral small vessel disease (SVD). The authors studied the neuroimaging correlates of cognitive performances among patients with stroke associated with SVD. METHODS: The authors per formed cerebral computed tomography, magnetic resonance imaging, and diffusion-weighted imaging among 74 consecutive patients admitted to the acute stroke unit because of stroke associated with SVD. They examined the association between cognitive performances and the following neuroimaging features: volume of white matter changes (WMC), multiplicity of lacunae, location of lacunae, total cerebral atrophy, and frontal and medial temporal lobe atrophy. RESULTS: Apart from age and education, univariate linear regression analyses revealed that WMC volume, presence of thalamic lacunae, cerebral atrophy, and left frontal lobe atrophy predicted performance on the Mini-Mental State Examination while WMC volume, presence of thalamic infarcts, cerebral atrophy, and frontal lobe atrophy of both sides predicted performance on the Mattis Dementia Rating Scale-Initiation/Preservation subscale. In the multivariate analyses, education (R2=0.22, P<.001), left frontal lobe atrophy (R2=0.10, P=.004), and presence of thalamic lacunae (R2=0.04, P=.049) were found to predict performance on the Mini-Mental State Examination while age (R2=0.23, P<.001) and presence of thalamic lacunae (R2=0.08, P=.011) were found to predict performance on the Mattis Dementia Rating Scale-Initiation/Preservation. CONCLUSIONS: Among patients with stroke associated with SVD, thalamic lacunae and frontal lobe atrophy are key determinants of cognitive performances.

Age Factors↗
PubMed2005

Magnetic resonance coronary angiography with 3D TrueFISP: breath-hold versus respiratory gated imaging.

To compare the diagnostic accuracy of coronary magnetic resonance angiography with three-dimensional (3D) trueFISP breath-hold and respiratory gated techniques for the detection of significant coronary artery stenosis. 15 patients who recently underwent elective coronary angiogram were studied and a total of 60 arteries and 48 arteries were assessed by breath-hold and respiratory gated 3D trueFISP techniques, respectively. The image quality, length of artery visualized and the presence or absence of significant coronary artery stenosis were recorded. 83.3% and 81.7% of the arteries obtained with the respiratory gated and the breath-hold techniques, respectively, had an image quality suitable for further analysis. There was no significant difference in the length of artery visualized. Sensitivity and specificity of 80%, 100% and 75% and 100%, respectively, were obtained with the breath-hold and respiratory gated techniques in detecting significant stenosis in the coronary arteries. Both techniques have moderate sensitivity and high specificity in detection of significant stenosis in the visualized segments of the major coronary arteries. However, they cannot replace conventional coronary angiogram for diagnosing coronary artery disease at present. Further studies are required to evaluate whether breath-hold approach is more efficient, therefore should be performed first and respiratory gated approach reserved for those who cannot breath-hold.

Adult↗
PubMed2005

Role of imaging in management of hemophilic patients.

OBJECTIVE: The purpose of this study was to evaluate the role of symptomatology and conventional radiographic scoring in predicting synovial hypertrophy, which could affect the clinical management of hemophilic patients. MATERIALS AND METHODS: Twenty males (mean age, 14.3 years old) with hemophilic arthropathy, including 34 symptomatic joints and 26 asymptomatic joints (16 knees, 20 ankles, and 24 elbows) had conventional radiographs of individual joints obtained that were rated according to the Arnold-Hilgartner stage and the Pettersson score. The patients also underwent MRI for the detection of synovial hypertrophy. The association of synovial hypertrophy and symptomatology was evaluated using the chi-square or Fisher's exact test. The best sensitivity, specificity, and positive and negative predictive values in detection of synovial hypertrophy using symptomatology and radiographic scoring were calculated. RESULTS: A significant association was seen between symptomatology and synovial hypertrophy of the knee and ankle joints (p < 0.05). The sensitivity, specificity, and positive and negative predictive values of symptomatology in detection of synovial hypertrophy of the knee were 100%, 78%, 78%, and 100%, respectively, and for the ankle were 83%, 75%, 83%, and 75%, respectively. The Arnold-Hilgartner stage and Pettersson score of the radiograph had a significant association with synovial hypertrophy of the knee and ankle joints (p < 0.05). Arnold-Hilgartner staging provided a better prediction of synovial hypertrophy, with sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 100%, 100%, and 100% for knees and 82%, 100%, 100%, and 82% for ankles. CONCLUSION: In hemophilic patients, the presence of symptomatology in the knee and ankle joints is associated with synovial hypertrophy, and scoring of the conventional radiographs using Arnold-Hilgartner staging is useful for the prediction of synovial hypertrophy.

Adolescent↗
PubMed2004

Multiple acute cerebral infarcts on diffusion-weighted imaging and risk of recurrent stroke.

Multiple acute cerebral infarcts (MACIs) detected by diffusion-weighted imaging (DWI) may indicate an unstable source of thromboembolism. The authors studied 119 consecutive acute ischemic stroke patients within 24 hours of onset with DWI. MACIs were present in 20 patients (16.8%). During the follow-up period, there were 15 recurrent strokes, 3 acute coronary syndromes, and 5 deaths. MACI was the only significant independent predictor for vascular events and death (odd ratio [OR]] = 4.34; p = 0.001) and stroke recurrence (OR = 5.93; p = 0.001).

Acute Disease↗
PubMed2004

Albuminuria is a marker of increasing intracranial and extracranial vascular involvement in Type 2 diabetic Chinese patients.

AIMS/HYPOTHESIS: Albuminuria has been reported to be a marker of cardiovascular risk factors and disease morbidity and mortality, but its relationship with intracerebral atherosclerotic disease is less clear. The aim of this study was to investigate the association between albuminuria and intracranial and extracranial vascular involvement in Chinese Type 2 diabetic patients. METHODS: The anthropometric and fasting biochemical measurements of 966 Type 2 diabetic patients with normoalbuminuria (55.6%), microalbuminuria (27.7%) or macroalbuminuria (16.7%) were compared. The prevalence of microvascular and macrovascular disease and middle cerebral artery (MCA) stenosis, measured by transcranial Doppler ultrasound, were also compared between the groups. RESULTS: Albuminuria was closely associated with a range of adverse parameters, including high BP, dyslipidaemia, smoking and adiposity (all p<0.01). The prevalence of microvascular disease (retinopathy p<0.001) and macrovascular disease (peripheral vascular disease p=0.012, myocardial infarction, p=0.004, MCA stenosis p<0.001) increased significantly with increasing levels of albuminuria. Albuminuria was also found to be an independent predictor of microvascular and macrovascular disease. CONCLUSIONS/INTERPRETATION: Albuminuria was an independent predictor of increasing levels of vascular risk factors and microvascular and macrovascular disease in this group of Type 2 diabetic patients, and a possible role for albuminuria as a marker of intracranial cerebrovascular disease should be further investigated.

Aged↗
PubMed2004

Post-operative magnetic resonance evaluation of children after laparoscopic anorectoplasty for imperforate anus.

BACKGROUND AND AIMS: Laparoscopic anorectoplasty (LAR) is a relatively new procedure in the treatment of imperforate anus. Using magnetic resonance imaging (MRI), we evaluated the anatomical features of the anorectal region of children treated with LAR and compared this with conventional posterior sagittal anorectoplasty (PSARP). The findings were correlated with functional outcome. PATIENT/METHODS: A retrospective review of ten children with the high/intermediate types of imperforate anus underwent LAR between May 2000 and December 2002. MRI of the pelvis was performed post-operatively and a semi-quantitative score was used to assess the degree of sphincter symmetry, peri-rectal fibrosis, and the position of the pull-through rectum. The defecation status of these patients was also recorded. Eight historical patients who had undergone PSARP served as a control group. RESULTS/FINDINGS: When compared with PSARP patients, a significantly lower proportion of LAR patients had sphincter asymmetry (40 vs. 100%, p < 0.05) and peri-rectal fibrosis (40 vs. 87.5%, p < 0.05). The positioning of the rectum was, however, central for both groups (90 vs. 87.5%). No statistical correlation was found between defecation status and the degree of sphincter asymmetry or peri-rectal fibrosis. INTERPRETATION/CONCLUSION: LAR allows more optimal anatomical reconstruction for patients with the high/intermediate types of imperforate anus. However, additional factors that are not correctable by surgery, such as intrinsic innervation deficiency, also influence the clinical outcome.

Anal Canal↗
PubMed2004

Computer-assisted detection as a second reader in symptomatic Asian women with palpable breast cancer.

PURPOSE: To determine the potential role of a computer-assisted detection (CAD) algorithm as a second reader for experienced and inexperienced radiologists in mammography reading in Asian women. MATERIAL AND METHODS: Two-view mammograms performed in 124 consecutive patients who presented with palpable breast cancer masses were retrospectively evaluated by two experienced breast radiologists (7 and 10 years' experience). The original reports of the session radiologists with variable experience of reading mammograms (2 to more than 10 years) were also evaluated. The number of suspicious masses and microcalcification clusters detected in each patient by both groups of radiologists were recorded. The radiologists then re-evaluated the films with the CAD system as a second reader. Any improvement in the detectability of breast pathology by either the experienced radiologists and/or by the session radiologists was then assessed. A total of 127 breasts had biopsy-proven carcinoma; 74 breasts had mastectomy performed. All the imaging results were correlated with tru-cut biopsy or mastectomy histology. RESULTS: With CAD-aided interpretation, there were altogether 95 visible masses and 77 suspicious microcalcification clusters in 109 mammographically detectable cancers correlated with histology results. There was a 7.4% (7/95) and 10.4% (8/77) increase in the number of masses and microcalcification clusters detected, respectively, by the experienced radiologists after application of CAD, whereas the increase was 13.7% (13/95) and 27.3% (21/77) for detection of masses and microcalcifications by the session radiologists, respectively. In 9 patients, a secondary focus detected by CAD was confirmed by histology. Three patients had contralateral breast tumors, 1 had a satellite invasive tumor while 5 had ductal carcinoma in situ on the same breast. Based on the biopsies and 74 mastectomies, the true-positive and false-positive detection rate of CAD was 92.6% and 31.8% for detection of carcinomas. The true-positive and false-positive detection rates were 100% and 58.8% for microcalcification clusters. CONCLUSION: The current generation CAD algorithm helped to improve the detection rate of carcinomas, calcifications and multifocality in Asian breasts.

Adult↗
PubMed2004

Dynamic gadolinium-enhanced magnetic resonance urography for assessing drainage in dilated pelvicalyceal systems with moderate renal function: preliminary results and comparison with diuresis renography.

OBJECTIVE: To evaluate the use of dynamic gadolinium diethylenetriaminepenta-acetic acid (DTPA)-enhanced magnetic resonance urography (Gd-MRU) for assessing kidneys with markedly dilated pelvicalyceal systems and impaired function. PATIENTS AND METHODS: Eight children (mean age 30 months, sd 25) were assessed, diagnosed as having gross unilateral hydronephrosis with a mean (sd) anteroposterior renal pelvic diameter of 36 (7) mm and reduced (30-40%) renal function. Dynamic Gd-MRU was performed after the patients were pre-loaded with intravenous fluid and diuretics, and comprised a dynamic T1-weighted sequence after Gd-DTPA (0.1 mmol/kg body weight) was administered, with a time-intensity curve of each kidney produced. Drainage was diagnosed by a clearly declining time-intensity curve and direct visualization of contrast medium within the ureter in several frames. High-grade or complete obstruction was diagnosed when drainage of contrast medium could not be detected. Gd-MRU results were compared with diuresis radionuclide (mercapto-acetyltriglycine, MAG3) renography within the same week. Unobstructive units detected by Gd-MRU were treated conservatively with a close follow-up by ultrasonography and radionuclide studies. RESULTS: Diuresis MAG3 renography showed drainage in three dilated units and poor washout in five; in contrast, Gd-MRU showed drainage in seven dilated systems (three showed poor washout by MAG3), and obstruction in the remaining case. The unobstructed units detected by MRU under conservative treatment thus showed no further deterioration of renal function or progressive hydronephrosis in the subsequent follow-up (mean 18 months, range 15-23). CONCLUSION: These preliminary results suggest that dynamic Gd-MRU is a useful noninvasive imaging method in distinguishing obstructive from unobstructive dilated systems, particularly in patients with hydronephrosis and reduced renal function.

Child↗