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Chen Y, Chen X, Mok VCT, Lam WWM, Wong KS, Tang WK. Poststroke depression in patients with small subcortical infarcts. Clin Neurol Neurosurg 2008; 111:256-60. [PMID: 19036495 DOI: 10.1016/j.clineuro.2008.10.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 09/10/2008] [Accepted: 10/11/2008] [Indexed: 11/19/2022]
Abstract
OBJECTIVES Small subcortical infarcts (SSIs) can result from small vessel disease (SVD) and intracranial and extracranial large artery disease (LAD). No study has explored poststroke depression (PSD) in different etiological types of SSIs. METHODS Patients with SSIs resulting from LAD and SVD were included in the study. Poststroke depression was evaluated with the 15-item version of the geriatric depression scale (GDS) 3 months after stroke. RESULTS Of the 127 patients with SSIs, 44 had LAD and 83 had SVD. The LAD group had a significantly higher mean GDS score and higher frequency of PSD (p<0.05). The etiological type LAD was a significant independent risk factor for PSD. CONCLUSION PSD is more common in patients with SSIs resulting from LAD. This suggests that cerebral blood perfusion may play an important role in the development of PSD.
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Lam WWM, Au WY, Chu WCW, Tam S, Ha SY, Pennell DJ. One-stop measurement of iron deposition in the anterior pituitary, liver, and heart in thalassemia patients. J Magn Reson Imaging 2008; 28:29-33. [PMID: 18581349 DOI: 10.1002/jmri.21433] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To assess the feasibility of one-stop evaluation of iron load of myocardium, liver, and anterior pituitary gland in thalassemia patients. MATERIALS AND METHODS Fifty thalassemia major patients underwent a breath-hold magnetic resonance imaging (MRI) sequence for assessment of T2* for liver and myocardium, a short axis cine trueFISP sequence covering base to apex to assess the ejection fraction of left ventricle, and a turbo spin echo T2-weighted sequence for the anterior pituitary gland. The MRI parameters were correlated with serum growth hormone, insulin growth factor-1 (IGF-1), insulin growth factor binding protein-3 (IGFBP-3), and endocrine failure. RESULTS Ferritin was found to be associated with T2* liver (P < 0.005), T2SI (signal intensity) pituitary (P = 0.001), and T2 pituitary/fat (P = 0.001), but not with T2* heart. There was significant correlation of T2SI pituitary with IGF-1 and IGFBP-3. T2* liver (P < 0.001), T2* heart (P < 0.001), pituitary SI (P < 0.001) and pituitary/fat SI (P = 0.002) were also found to be significantly correlated with a history of hypogonadism. T2* heart was also found to be significantly correlated with IGF-1. CONCLUSION A quick MRI protocol for assessment of T2* liver, T2* heart, and T2SI pituitary is technically feasible. This might form an objective basis to monitor the response to different organs to chelation therapy.
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Leung TW, Yu SCH, Lam WWM, Wong LKS. The NIH registry on use of the Wingspan stent for symptomatic 70-99% intracranial arterial stenosis. Neurology 2008; 71:1124; author reply 1124-5. [PMID: 18824679 DOI: 10.1212/01.wnl.000032353.550765.3c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Liu T, Chu WCW, Young G, Li K, Yeung BHY, Guo L, Man GCW, Lam WWM, Wong STC, Cheng JCY. MR analysis of regional brain volume in adolescent idiopathic scoliosis: neurological manifestation of a systemic disease. J Magn Reson Imaging 2008; 27:732-6. [PMID: 18302230 DOI: 10.1002/jmri.21321] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To investigate whether regional brain volumes in adolescent idiopathic scoliosis (AIS) patients differ from matched control subjects as AIS subjects are reported to have poor performance on combined visual and proprioceptive testing and impaired postural balance in previous studies. MATERIALS AND METHODS Twenty AIS female patients with typical right-convex thoracic curve (age range,11-18 years; mean, 14.1 years) and 26 female controls (mean age, 14.8 years) underwent three-dimensional magnetization prepared rapid acquisition gradient echo (3D-MPRAGE) MR imaging. Volumes of 99 preselected neuroanatomical regions were compared by statistical parametric mapping and atlas-based hybrid warping. RESULTS Analysis of variance statistics revealed significant mean volumetric differences in 22 brain regions between AIS and controls. Ten regions were larger in AIS including the left frontal gyri and white matter in left frontal, parietal, and temporal regions, corpus callosum and brainstem. Twelve regions were smaller in AIS, including right-sided descending white matter tracts (anterior and posterior limbs of the right internal capsule and the cerebral peduncle) and deep nucleus (caudate), bilateral perirhinal cortices, left hippocampus and amygdala, bilateral precuneus gyri, and left middle and inferior occipital gyri. CONCLUSION Regional brain volume difference in AIS subjects may help to explain neurological abnormalities in this group.
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Tse GMK, Ma TKF, Lui PCW, Ng DCH, Yu AMC, Vong JSL, Niu Y, Chaiwun B, Lam WWM, Tan PH. Fine needle aspiration cytology of papillary lesions of the breast: how accurate is the diagnosis? J Clin Pathol 2008; 61:945-9. [DOI: 10.1136/jcp.2008.057489] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Chow PC, Liang XC, Cheung EWY, Lam WWM, Cheung YF. New two-dimensional global longitudinal strain and strain rate imaging for assessment of systemic right ventricular function. Heart 2008; 94:855-9. [DOI: 10.1136/hrt.2007.131862] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Leung TW, Lam WWM, Yu SCH, Leung CSF, Soo YOY, Wong LKS. Multimodal computed tomography evaluation before thrombolysis in acute ischaemic stroke. Hong Kong Med J 2008; 14:236-239. [PMID: 18525096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
Currently, when stroke patients are offered thrombolytic therapy, their ischaemic stroke subtypes are usually unknown. Given the risk of haemorrhage that accompanies thrombolytic therapy, unselective (or undiscriminating) use of recombinant tissue plasminogen activator in patients without large-artery thromboemboli is potentially hazardous. Advances in computed tomography techniques have enabled the stroke pathophysiology to be quickly delineated by multimodal computed tomography without compromise in time for recombinant tissue plasminogen activator administration. Through description of the investigation of a typical stroke patient, we report how this technique is feasible in a regional hospital and may guide judicious use of recombinant tissue plasminogen activator.
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Lam WWM, Chan CP, Chan CF, Mak CCC, Chan CF, Chong KWH, Leung MHJ, Tang MH. Factors affecting the palpability of breast lesion by self-examination. Singapore Med J 2008; 49:228-232. [PMID: 18363005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
INTRODUCTION This study aims to assess the accuracy of detection of breast lesion by breast self-examination and to assess different factors affecting the accuracy. METHODS All consecutive Chinese female patients, who attended our breast imaging unit in 2001, completed our questionnaire, had retrievable hard copy films, and had more than three years clinical follow-up, were recruited for this study. Different factors, such as age, menopausal status, previous experience of breastfeeding, family history of breast cancer, previous history of mastectomy or lumpectomy, hormonal therapy, oral contraceptive pills and previous history of mammography, were correlated with accuracy in self-detection of breast lesions retrospectively. The nature, size and location of the lesion, and breast size based on imaging, were also correlated with the accuracy in self-detection of breast lesions. RESULTS A total of 163 questionnaires were analysed. 111 patients detected a breast lesion themselves and 24 of these lesions were false-positives. A total of 173 lesions (27 cancerous, 146 benign lesions) were documented by either ultrasonography and/or mammography, and confirmed by either histology or three-year clinical follow-up. The overall sensitivity in detecting both benign and malignant breast lesions was 71% when number of breast lesions was used as the denominator, and up to 78% sensitivity was achieved when number of patients was used as the denominator. History of mastectomy, and size and nature of the lesions were found to affect the accuracy of self-detection of breast lesions. CONCLUSION Overall, breast self-examinations were effective in the detection of breast lesions and factors such as size of lesion, nature of the lesion and history of mastectomy affect the accuracy of the detections. Breast self-examination should be promoted for early detection of breast cancer.
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Mok VCT, Liu T, Lam WWM, Wong A, Hu X, Guo L, Chen XY, Tang WK, Wong KS, Wong S. Neuroimaging predictors of cognitive impairment in confluent white matter lesion: volumetric analyses of 99 brain regions. Dement Geriatr Cogn Disord 2008; 25:67-73. [PMID: 18042992 DOI: 10.1159/000111692] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/05/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Although confluent white matter lesion (WML) is associated with cognitive impairment, the mechanism explaining this association is controversial. We aimed to investigate comprehensively the MRI predictors of cognitive impairment in confluent WML. METHODS Among 45 lacunar stroke patients who had confluent WML, we evaluated the association of executive function [Mattis Dementia Rating Scale - Initiation/Perseveration subscale (MDRS I/P)] and global cognition [Mini-Mental State Examination (MMSE)] with the volume of WML, measures of lacunes and microbleeds, and the volumes of 99 other specific brain regions. RESULTS Regression analyses showed that WML volume predicted performance on the MDRS I/P (beta = -0.34, p = 0.016) independent of age. Volumes of cortical gray matter (cGM; beta = 0.41, p = 0.003), the lateral fronto-orbital gyrus (beta = 0.38, p = 0.01), superior frontal gyrus (beta = 0.29, p = 0.04), lateral ventricle (beta = -0.30, p = 0.04), and posterior limb of the internal capsule (beta = 0.43, p = 0.002) predicted MDRS I/P performance independent of WML volume. Volumes of cGM, and the lateral fronto-orbital gyrus predicted MMSE performance as well. CONCLUSION Atrophy along the frontosubcortical pathways and cGM predict cognition in confluent WML independent of WML volume.
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Mok V, Wong A, Ho S, Leung T, Lam WWM, Wong KS. Rivastigmine in Chinese patients with subcortical vascular dementia. Neuropsychiatr Dis Treat 2007; 3:943-8. [PMID: 19300631 PMCID: PMC2656338 DOI: 10.2147/ndt.s2221] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND We explored the efficacy and tolerability of rivastigmine among Chinese patients with subcortical vascular dementia. METHODS Forty subjects were randomized to either placebo (n = 20) or rivastigmine (n = 20) in a double-blind 26-week trial. Outcome measures were cognition (mini-mental state examination, frontal assessment battery), neuropsychiatric inventory (NPI), instrumental activities of daily living, clinical dementia rating scale, and adverse events. RESULTS No statistical significant benefit could be observed in the active group in any of the efficacy measures. A trend favoring active group was observed only in the NPI subscore of irritability (p = 0.066) and aberrant motor behavior (p = 0.068). Withdrawal rate was 30% and 15% in the active and placebo group, respectively. CONCLUSION Among Chinese subcortical vascular dementia patients, there was no apparent cognitive benefit associated with use of rivastigmine over the 6 months period. A trend favoring rivastigmine was observed in certain behavioral measures. Rivastigmine was associated with more withdrawals relative to placebo.
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Abstract
The study is to determine the optimal MRI bowel preparation regime for visualization of the stomach anatomy. Eight healthy volunteers were asked to take water, 75% barium and blueberry juice. The image quality and tolerance of different stomach distension regime were evaluated. Blueberry juice gave the best distension, but the signal intensity was not very homogeneous. Taking into account the image quality, tolerability and adverse effects, it is concluded that water is the most desirable oral contrast for MR stomach imaging.
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Tse GM, Tan PH, Cheung HS, Chu WCW, Lam WWM. Intermediate to highly suspicious calcification in breast lesions: a radio-pathologic correlation. Breast Cancer Res Treat 2007; 110:1-7. [PMID: 17674189 DOI: 10.1007/s10549-007-9695-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2007] [Accepted: 07/16/2007] [Indexed: 02/07/2023]
Abstract
Breast calcification is an important feature in the radiological assessment of breast lesions. There are well established diagnostic criteria basing on the morphology and distribution of the calcifications radiologically with recommendation protocols. Pathologically, calcifications in breast lesions are of dystrophic type, and may occur in either the secretory materials or necrotic debris, with inflammation and osteopontin being plausible mediators. Detection of calcium phosphate (hydroyapaptite) is considerably easier than calcium oxalate. Radiologically amorphous calcification represents a borderline type of calcification, and occurs in both benign and malignant (low grade) lesions, and warrants careful follow up and investigation. Clustering of calcification alone may not be an accurate predictor for malignancy, but when there are associated features like pleomorphism, branching, architectural distortion, and associated mass or density, the predictive value for malignant increases. Adequate sampling of calcification in the biopsy is crucial in the management of patients; in general, needle core biopsy or mammotome biopsy achieve satisfactory calcification retrieval. In a benign biopsy that fails to identify the calcifications visible in the mammography, further evaluation or cutting of the histologic block is recommended to minimize the potential of a false negative investigation.
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Chu WCW, Man GCW, Lam WWM, Yeung BHY, Chau WW, Ng BKW, Lam TP, Lee KM, Cheng JCY. A detailed morphologic and functional magnetic resonance imaging study of the craniocervical junction in adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 2007; 32:1667-74. [PMID: 17621216 DOI: 10.1097/brs.0b013e318074d539] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Conventional and phase-contrast magnetic resonance (MR) imaging were used to evaluate the morphology and cerebrospinal fluid (CSF) flow dynamics at craniocervical junction in adolescent idiopathic scoliosis (AIS). OBJECTIVES To determine the morphology of cerebellar tonsil, foramen magnum, and dynamic flow of CSF at the craniocervical junction in AIS patients versus normal controls and their correlation with somatosensory cortical evoked potentials (SSEP). SUMMARY OF BACKGROUND DATA Previous studies have documented obstructed CSF flow in patients with Chiari I malformation. Low-lying cerebellar tonsils and syringomyelia are also observed in AIS patients. We sought to investigate whether disturbed CSF flow is also evident in AIS subjects at the foramen magnum level and its association with level of cerebellar tonsils and dimensions of foramen magnum. METHODS Conventional and phase-contrast MR were performed in 105 adolescent girls (69 AIS subjects and 36 age-matched controls). Measurements of cerebellar tonsillar level related to the basion-opsithion (BO) line, anteroposterior (AP), transverse (TS) diameter, and area of foramen magnum, and peak velocity of CSF flow in both the anterior and posterior subarachnoid space through foramen magnum were obtained. Correlations were made among different parameters and SSEP findings. RESULTS A total of 42% of subjects in the AIS group had the cerebellar tonsillar tip positioned 1 mm below the BO line. The cerebellar tonsillar level in AIS subjects was significantly lower than the median tonsillar level in normal controls (P < 0.01). The AP diameter and area of foramen magnum were significantly larger in AIS subjects when compared with normal controls (P < 0.05), but the peak CSF velocities through foramen magnum showed no significant difference (P > 0.05). CONCLUSION Peak CSF velocities through foramen magnum were not significantly different in AIS subjects despite the presence of low-lying cerebellar tonsils. This might be explained by the compensatory effect of larger foramen magnum in AIS subjects.
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Chu WCW, Tam YH, Lam WWM, Ng AWH, Sit F, Yeung CK. Dynamic MR assessment of the anorectal angle and puborectalis muscle in pediatric patients with anismus: technique and feasibility. J Magn Reson Imaging 2007; 25:1067-72. [PMID: 17410575 DOI: 10.1002/jmri.20914] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To assess the feasibility of dynamic breath-hold MRI for evaluating changes in the anorectal angle and movements of the pelvic-floor musculature (puborectalis) during resting and straining states in pediatric patients presenting with anismus. MATERIALS AND METHODS Six pediatric patients (7-13 years old) with chronic constipation and manometric evidence of anismus were assessed by dynamic breath-hold MRI. Changes in the anorectal angle, the degree of pelvic-floor descent, and the thickness and length of the puborectalis muscles were measured during rest and straining. The findings were compared with those obtained in six age- and sex-matched controls. RESULTS The children with anismus had a smaller anorectal angle during straining, and the angle decreased from rest to defecation. The puborectalis also became paradoxically shortened and thickened during straining in the anismus group. There were significant differences between the two groups in terms of the change of degree of the anorectal angle, and the thickness and length of the puborectalis muscle during straining. CONCLUSION Fast dynamic MRI is feasible for evaluating pelvic-floor movement in pediatric patients. Preliminary results suggest that children with anismus have a smaller anorectal angle and a different puborectalis configuration compared to controls.
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Wong A, Mok VCT, Tang WK, Lam WWM, Wong KS. Comparing Mattis Dementia Rating Scale--initiation/perseveration subset and frontal assessment battery in stroke associated with small vessel disease. J Clin Exp Neuropsychol 2007; 29:160-9. [PMID: 17365251 DOI: 10.1080/13803390600582453] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Forty-two controls and 32 patients with stroke associated with small vessel disease (SSVD) were administered the Mattis Dementia Rating Scale Initiation / Perseveration subset (MDRS I/P) and Frontal Assessment Battery (FAB). Both tests showed comparably good ability in Receiver Operating Characteristics curves analysis (AUCMDRS I/P=0.887; AUC FAB=0.854, p=.833) in discriminating between controls and patients and correctly classified over 78% of subjects. Verbal fluency and motor programming contributed most to the discriminating power in the two tests. The MDRS I/P and FAB are useful in discriminating between controls and SSVD patients in a hospital setting.
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Han JH, Ho SSY, Lam WWM, Wong KS. Total cerebral blood flow estimated by color velocity imaging quantification ultrasound: a predictor for recurrent stroke? J Cereb Blood Flow Metab 2007; 27:850-6. [PMID: 16985507 DOI: 10.1038/sj.jcbfm.9600392] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although the Virchow's triad on thrombosis includes reduced blood flow as a factor, there has been relatively little data on the importance of total cerebral blood flow on the risk of subsequent stroke. In the current study, we investigate whether total cerebral blood flow helps predict stroke recurrence. Extracranial arterial blood flow volume estimated by color velocity imaging quantification ultrasound (CVIQ) is an index of cerebral blood flow measurement. We performed a cohort study of 210 consecutive acute stroke patients. Patients were studied with transcranial Doppler and duplex ultrasound for intra- and extracranial large artery disease within 3 days of symptom onset. The association between the risk of recurrent stroke and CVIQ was analyzed with Cox proportional hazards model. Thirty-nine patients (17.7%) developed an ischemic stroke during a mean follow-up of 47.5 months. The mean extracranial blood flow volume was significantly lower for patients who had a recurrent stroke than those without (594.4+/-130.3 versus 683.8+/-176.9 mL/min; P=0.003). In a Cox proportional hazards model adjusting for potential confounding variables, extracranial blood flow volume (hazard ratio (HR) for lowest tertile, 4.1; 95% confidence interval (CI), 1.5 to 11.0) along with male sex (HR, 2.5; 95% CI, 1.3 to 5.1), diabetes (HR, 2.5; 95% CI, 1.2 to 5.0) and large artery stenosis (HR, 2.2; 95% CI, 1.1 to 4.4) were independent predictors for stroke recurrence. Our data indicated that patient with low amount of blood flow to the brain is at risk of recurrent stroke.
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King AD, Ahuja AT, Yeung DK, Wong JKT, Lee YYP, Lam WWM, Ho SSM, Yu SCH, Leung SF. Delayed complications of radiotherapy treatment for nasopharyngeal carcinoma: imaging findings. Clin Radiol 2007; 62:195-203. [PMID: 17293211 DOI: 10.1016/j.crad.2006.10.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 09/29/2006] [Accepted: 10/03/2006] [Indexed: 11/20/2022]
Abstract
Radiotherapy is used to treat a wide variety of head and neck tumours that arise in and around the skull base. The delayed effects of radiation damages a range of structures, including the nervous system, bone, major vessels, mucus membranes, pituitary and salivary glands, as well as increasing the risk of radiation-induced neoplasms. In this review the complications resulting from radiation treatment for nasopharyngeal carcinoma (NPC), a cancer treated with a high dose of radiation to a fairly large region, are illustrated. Many patients with NPC have a long-term survival, so are at risk of developing delayed radiation effects, and hence may demonstrate a wide range of complications on imaging. Other tumours around the skull base treated with radiotherapy include meningiomas, chordomas, chondrosarcomas, pituitary adenomas, paranasal sinus and nasal cavity tumours. In these cases similar complications may be encountered on imaging, although the severity, incidence and location will vary.
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Ka-Tak W, Lam WWM, Yu SCH. MDCT of an Aberrant Right Subclavian Artery and of Bilateral Vertebral Arteries with Anomalous Origins. AJR Am J Roentgenol 2007; 188:W274-5. [PMID: 17312035 DOI: 10.2214/ajr.05.0694] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Wong TYY, Lam WWM, Lau TK. Foetal magnetic resonance imaging. Hong Kong Med J 2006; 12:486-7. [PMID: 17148808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023] Open
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Chu WCW, Mok GCF, Lam WWM, Yam MC, Sung RYT. Assessment of coronary artery aneurysms in paediatric patients with Kawasaki disease by multidetector row CT angiography: feasibility and comparison with 2D echocardiography. Pediatr Radiol 2006; 36:1148-53. [PMID: 16912893 DOI: 10.1007/s00247-006-0281-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 06/28/2006] [Accepted: 07/02/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND Transthoracic ECHO is the locally accepted method for coronary surveillance of patients with Kawasaki disease but it may have limited visualization in the older child. OBJECTIVE To assess the feasibility of multidetector CT (MDCT) angiography in the follow-up of coronary artery aneurysms in children with previous Kawasaki disease. MATERIALS AND METHODS Six children (5 boys, 1 girl; mean age 11.5 years) with known Kawasaki disease and coronary artery involvement underwent CT coronary angiography using 16-detector MDCT. The visualized lengths and diameter of all coronary segments were measured. The number, size and location of coronary artery aneurysms were recorded and compared with recent ECHO. RESULTS Twelve coronary artery aneurysms (seven saccular, five fusiform) were identified by MDCT angiography. One saccular aneurysm at the junction of the distal right coronary artery and posterior descending artery was not detected by ECHO while the remaining six in proximal segments were detected by both modalities. Two of five fusiform aneurysms were not detected by ECHO due to their small sizes. Excellent agreement was found between CT and ECHO for maximal diameter and length of the visualized aneurysms. CONCLUSIONS MDCT angiography accurately defines coronary artery aneurysms. It is more sensitive for detecting aneurysms at distal coronary segments and fusiform aneurysms of small size.
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Wen HM, Baum L, Cheung WS, Mok V, Lam WWM, Tomlinson B, Wong KS, Ng HK. Apolipoprotein E ?4 allele is associated with the volume of white matter changes in patients with lacunar infarcts. Eur J Neurol 2006; 13:1216-20. [PMID: 17038035 DOI: 10.1111/j.1468-1331.2006.01436.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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.
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Chu WCW, Li AM, Ng BKW, Chan DFY, Lam TP, Lam WWM, Cheng JCY. Dynamic magnetic resonance imaging in assessing lung volumes, chest wall, and diaphragm motions in adolescent idiopathic scoliosis versus normal controls. Spine (Phila Pa 1976) 2006; 31:2243-9. [PMID: 16946662 DOI: 10.1097/01.brs.0000232822.74349.32] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Dynamic breath-hold (BH)- magnetic resonance (MR) imaging was used to evaluate lung function in adolescent idiopathic scoliosis (AIS). OBJECTIVES Changes in lung volume, chest wall, and diaphragmatic motions were evaluated in AIS patients and compared with normal controls. SUMMARY OF BACKGROUND DATA Little is known about whether pulmonary function impairment in AIS is related to restriction of lung volume, poor chest wall expansibility, or impaired diaphragmatic motion. This is a study on the underlying pathophysiology of the abnormal pulmonary function in AIS using the ultrafast BH-MR imaging technique. METHODS Forty-two patients with moderate to severe right thoracic scoliosis (Cobb angle, 40 degrees -98 degrees), 22 patients with mild right thoracic scoliosis (Cobb angle 10 degrees -30 degrees), and 12 healthy subjects (age ranged, 11-18 years; all girls) were recruited for the following assessments: 1) inspiratory, expiratory, and change in lung volume; 2) change in anteroposterior (AP) and transverse (TS) diameter of the chest wall at two levels: carina and apical vertebra level; and 3) change in diaphragmatic heights. RESULTS Inspiratory, expiratory lung volume and diaphragmatic heights were significantly reduced in the severe scoliosis group (P < 0.05), but the change in lung volume was not affected. There was no significant difference in the change of AP or TS diameter of the chest wall as well as diaphragmatic motions among groups. CONCLUSION Impairment in lung function in AIS patients is predominantly due to restriction of lung volume.
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Chu WCW, Wong MS, Chau WW, Lam TP, Ng KW, Lam WWM, Cheng JCY. Curve correction effect of rigid spinal orthosis in different recumbent positions in adolescent idiopathic scoliosis (AIS): a pilot MRI study. Prosthet Orthot Int 2006; 30:136-44. [PMID: 16990224 DOI: 10.1080/03093640600578020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
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.
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Wang X, Lam WWM, Fan YH, Graham CA, Rainer TH, Wong KS. Topographic Patterns of Small Subcortical Infarcts Associated with MCA Stenosis: A Diffusion-Weighted MRI Study. J Neuroimaging 2006; 16:266-71. [PMID: 16808829 DOI: 10.1111/j.1552-6569.2006.00027.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Small subcortical infarcts (SSI, maximum lesion diameter < or =2.0 cm) are usually considered as infarcts caused by small vessel disease. However, SSI can also be associated with large artery occlusive disease such as middle cerebral artery (MCA) stenosis. We performed a prospective study to investigate the relationship between MCA stenosis and SSI distribution and further to investigate the mechanism of SSI caused by MCA stenosis. METHODS Magnetic resonance angiography (MRA) and diffusion-weighed MRI (DWI) of consecutive acute ischemic stroke patients with recent SSI were studied. The distribution of acute infarcts on DWI was categorized as cortical infarct (CI), border zone infarct (BI), or perforating artery infarct (PAI). RESULTS Totally, 93 cases were recruited, among which 12 had single SSI with MCA stenosis (group 1) and 26 patients had multiple SSI with MCA stenosis (group 2), while 55 patients without MCA stenosis had single SSI (group 3). For patients with single SSI and MCA stenosis, 6 had BI and 6 had PAI; for patients with multiple SSI and MCA stenosis, 25 had BI, 4 had PAI and 9 had CI (compared with group 1: P= .001); for patients with single SSI but without MCA stenosis, 20 had BI and 35 had PAI (compared with group 1: P= .58). CONCLUSION Multiple acute infarcts along the border zone are the commonest pattern in small infarcts with MCA stenosis, especially among those with multiple acute infarcts. Our data suggest that hemodynamic compromise and artery-to-artery embolism may be both important factors for infarcts in patients with MCA stenosis.
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Chu WCW, Li AM, Ng AWH, So HK, Lam WWM, Lo KL, Yeung MCA, Yau YS, Chiu WK, Leung CW, Ng PC, Hon KL, Mo KW, Fok TF, Ahuja AT. Thin-Section CT 12 Months After the Diagnosis of Severe Acute Respiratory Syndrome in Pediatric Patients. AJR Am J Roentgenol 2006; 186:1707-14. [PMID: 16714663 DOI: 10.2214/ajr.05.0382] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
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.
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