Vincent Lai

Megalencephalic Leukoencephalopathy with Cysts without MLC1 Defect Two Phenotypes

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is an autosomal recessive disease characterized by early infantile macrocephaly and delayed motor and cognitive deterioration. Magnetic resonance imaging (MRI) shows diffusely abnormal and swollen cerebral white matter and subcortical cysts. On follow‐up, atrophy ensues. Approximately 80% of MLC patients have mutations in MLC1. We report 16 MLC patients without MLC1 mutations. Eight retained the classical clinical and MRI phenotype. The other 8 showed major MRI improvement. They lacked motor decline. Five had normal intelligence; 3 displayed cognitive deficiency. In conclusion, 2 phenotypes can be distinguished among the non‐MLC1 mutated MLC patients: a classical and a benign phenotype. ANN NEUROL 2010;67:834–837

Endovascular treatment paradigm of carotid blowout syndrome: Review of 8-years experience

OBJECTIVES Endovascular treatment is effective in treating carotid blowout syndrome (CBS). We reviewed our experience in addressing CBS over eight years and presented an account of the treatment paradigm and management algorithm. METHOD All cases of CBS from 2003 to 2010 with endovascular treatment performed in our center were reviewed. 15 CBS in 14 patients were recruited. Based on our management algorithm, treatment regimen was stratified into deconstructive or constructive methods. Their clinical presentations, angiographic features, angiographic and clinical outcomes were reviewed. RESULTS 10 patients were treated with deconstructive method by means of permanent vessel occlusion (PVO) and 4 patients were treated with constructive method by means of placement of covered stent (n=3) or flow diverting device (n=1). Immediate hemostasis was achieved in all cases. 7 (50%) patients, in whom 5 treated with PVO and 2 with covered stent, had favorable outcomes and survived at a median follow-up period of 4 months (range: 1-84 months). CONCLUSION Permanent vessel occlusion remains the gold standard of treatment and tends to show a favorable long-term outcome. Off-label use of covered stent and flow-diverting device can produce satisfactory results should balloon occlusion test fail, but long-term follow up would be required for definitive assessment.

Diagnostic power of various computed tomography signs in diagnosing acute appendicitis

OBJECTIVE To review the diagnostic power of various computed tomography (CT) signs in acute appendicitis, in particular those initially classified as inconclusive. MATERIALS AND METHODS Retrospective review of 100 CT abdomen and pelvis studies with assessment of maximal luminal diameter, wall thickness and cross-sectional diameter of the appendix, periappendiceal inflammatory changes, and presence of appendicolith. RESULTS All CT signs show statistically significant occurrences in acute appendicitis. Their respective cut-off values with best sensitivity and specificity were calculated. Those from the inconclusive cases were also reviewed. CONCLUSION Maximal cross-sectional diameter of the appendix is the most powerful parameter. Rest of the CT signs is supportive, especially in cases with inconclusive results.

Bridging Intimate Partner Violence and the Human Brain A Literature Review

Past studies mainly focused on the physical and structural brain injuries in women survivors with a history of intimate partner violence (IPV), but little attention has been given to the biological impact and cognitive dysfunction resulting from such psychological stress. In this article, we aim to establish the connection between IPV and the brain by reviewing current literature examining (1) the biological mechanisms linking IPV, stress, and the brain; (2) the functional and anatomical considerations of the brain in abused women; and (3) the abused women’s behavioral responses to IPV, including fear, pain, and emotion regulation, by utilizing functional neuroimaging. The major significance of this study is in highlighting the need to advance beyond self-reports and to obtain scientific evidence of the neurological impact and cognitive dysfunction in abused women with a history of IPV, an area in which current literature remains at a descriptive level.

Correlation between tissue metabolism and cellularity assessed by standardized uptake value and apparent diffusion coefficient in peritoneal metastasis

To evaluate the correlation between standardized uptake value (SUV) (tissue metabolism) and apparent diffusion coefficient (ADC) (water diffusivity) in peritoneal metastases.

Comparison of initial high resolution computed tomography features in viral pneumonia between metapneumovirus infection and severe acute respiratory syndrome

Abstract Objective To review and compare initial high resolution computed tomography (HRCT) findings in patients with metapneumovirus pneumonia and severe acute respiratory syndrome (SARS-Coronovirus). Materials and methods 4 cases of metapneumovirus pneumonia (mean age of 52.3years) in an institutional outbreak (Castle Peak Hospital) in 2008 and 38 cases of SARS-coronovirus (mean age of 39.6years) admitted to Tuen Mun hospital during an epidemic outbreak in 2003 were included. HRCT findings of the lungs for all patients were retrospectively reviewed by two independent radiologists. Results In the metapneumovirus group, common HRCT features were ground glass opacities (100%), consolidation (100%), parenchymal band (100%), bronchiectasis (75%). Crazy paving pattern was absent. They were predominantly subpleural and basal in location and bilateral involvement was observed in 50% of patients. In the SARS group, common HRCT features were ground glass opacities (92.1%), interlobular septal thickening (86.8%), crazy paving pattern (73.7%) and consolidation (68%). Bronchiectasis was not seen. Majority of patient demonstrated segmental or lobar in distribution and bilateral involvement was observed in 44.7% of patients. Pleural effusion and lymphadenopathy were of consistent rare features in both groups. Conclusion Ground glass opacities, interlobular septal thickening and consolidations were consistent HRCT manifestations in both metapneumovirus infection and SARS. The presence of bronchiectasis (0% in SARS) may point towards metapneumovirus while crazy paving pattern is more suggestive of SARS.

Reply to letter to the editor "why current evidence is against flow diverters for treatment of carotid blowout syndrome".

We agree that use of flow diverting device may not be ideal in ases of ruptured irradiation-induced carotid pseudoaneurysms, s the capability of re-endothelization of the injured vessel will e impaired due to irradiation necrosis. In addition, the risk of nfection will be significantly increased, further compromises the ealing process, as shown in our series. In contrary, two of our atients treated with covered stent demonstrated good clinical outomes with no recurrence of bleeding. One of them in particular ad been surviving for 84 months up to the latest follow-up and emained asymptomatic. Despite the small data size in our series, our initial experience avored the use of covered stent. Yet, the lack of a properly designed overed stent suitable for use in extracranial or intracranial carotid rtery raises concern of its long term safety and efficacy. The poor exibility of the covered stent may precipitate stent fracture or vesel injury if it is implanted in an unfavorable location such as turning

Prognostication of serial post-intensity-modulated radiation therapy undetectable plasma EBV DNA for nasopharyngeal carcinoma

Plasma Epstein-Barr virus (EBV) DNA titers have been used to monitor treatment response and provide prognostic information on survival for nasopharyngeal carcinoma (NPC). However, the long-term prognostic role of pretreatment and posttreatment titers after radical contemporaneous radiation therapy remains uncertain. We recruited 260 evaluable patients with non-metastatic NPC treated with radical intensity-modulated radiation therapy (IMRT) with or without adjunct chemotherapy. Plasma EBV DNA titers at baseline and then 8 weeks and 6 months after IMRT were measured. Cox regression models were employed to identify interaction between post-IMRT 8th week and 6th month undetectable titers and 3-year survival endpoints. Concordance indices (Ct) from time-dependent receiver-operating characteristics (TDROC) were compared between patients with post-IMRT undetectable and those with detectable titers. After a median follow-up duration of 3.4 years (range 1.4-4.6 years), patients with post-IMRT 8th week and 6th month undetectable plasma EBV DNA titers enjoyed longer 3-year survival endpoints than those who had detectable titers at the same time points. Post-IMRT 8th week, and more significantly, post-IMRT 6th month undetectable plasma EBV DNA were the only significant prognostic factors of 3-year survival endpoints. Ct values for all 3-year survival endpoints for both post-IMRT 8th week and 6th month undetectable plasma EBV DNA were significantly higher in those with stage IVA–IVB diseases compared to stage I-III counterparts. Early post-IMRT undetectable plasma EBV DNA titers were prognostic of 3-year survival endpoints in patients with non-metastatic NPC. Intensified treatment should be further explored for patients with persistently detectable titers after IMRT.

Radiation-Induced Peripheral Nerve Neurofibromata in a Patient Receiving Hypofractionated Radiation Therapy

SUMMARY: Radiation-induced peripheral nerve tumor, in particular a benign entity such as a neurofibroma, is rare, with only a few cases being reported so far. We demonstrate a case of radiation-induced neurofibromata along the left cervical nerve roots in a man with a background of localized targeted hypofractionated radiation therapy as adjuvant treatment for left cervical nodal metastasis complicating nasopharyngeal carcinoma. The toxicity of high-dose radiation in a hypofractionated regime is also stressed.

Intravoxel incoherent motion MR imaging in nasopharyngeal carcinoma: comparison and correlation with dynamic contrast enhanced MR imaging

Objectives To compare accuracy and assess agreement between intravoxel incoherent motion (IVIM) magnetic resonance (MR) perfusion-related parameters and quantitative dynamic contrast-enhanced (DCE) MR parameters in nasopharyngeal carcinoma (NPC). Results D, f, D*, Ktrans, Kep and Vp were significantly lower in the high stage group while Ve was significantly higher in the high stage group. Optimal cut-off values were: D=0.749 × 10−3 mm2/s; f=0.145; D*=100.401 × 10−3 mm2/s; Ktrans=0.571/min; Kep=0.8196/min; Ve=0.6556 %; Vp=0.0757 %. D* (p=0.001), Ktrans (p<0.001), Ve (p=0.014) were all reliable independent predictors for AJCC staging. IVIM-MR perfusion-related (f, D*) and DCE-MR (Ktrans, Kep, Ve, Vp) parameters were significantly correlated (p<0.001). Materials and Methods 75 patients with newly diagnosed NPC were prospectively recruited. Diffusion-weighted MR and DCE-MR imaging were performed with respective IVIM (D, f, D*) and DCE (Ktrans, Kep, Ve, Vp) MR parameters calculated. Patients were stratified into low and high tumor stage groups according to American Joint Committee on Cancer (AJCC) staging for determination of the predictive powers of IVIM-MR and DCE-MR parameters using t–test, ROC curve analyses and multiple logistic regression analysis. Correlation between IVIM-MR perfusion-related and DCE-MR parameters was assessed using Spearmans rank correlation. Conclusion IVIM-MR perfusion-related and quantitative DCE-MR parameters were significantly correlated in the assessment of NPC and were both reliable independent predictors in the prediction of AJCC staging. IVIM-MR perfusion imaging can be a potential useful non-invasive perfusion imaging tool for clinical use in the assessment of NPC.