Alexander Chris Vlantis

Prof. Alexander Chris Vlantis

Otorhinolaryngology, Head and Neck Surgery, Chinese University of Hong Kong, Hong Kong, China
orcid

Research Focus & Metrics

Academic Career Length

34Years (1993-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2004 in Radiology
Verified
Journal Article
Closed access
AKAnn D. King
Ann D. King
GTGary M. K. Tse
Gary M. K. Tse
AAAnil T. Ahuja
Anil T. Ahuja
EYEdmund H. Y. Yuen
Edmund H. Y. Yuen
AVAlexander Chris Vlantis
Alexander Chris Vlantis
AHAndrew C. van Hasselt
Andrew C. van Hasselt
To compare the diagnostic accuracy of computed tomography (CT), magnetic resonance (MR) imaging, and ultrasonography (US) in the detection of necrosis in metastatic cervical nodes from patients with head and neck squamous cell carcinoma. Twenty-seven patients (age range, 39-85 years; mean age, 62 years) with squamous cell carcinoma in the head and neck underwent CT, MR imaging, and US. Three radiologists evaluated the images for nodal necrosis. The results of each modality were analyzed for sensitivity, specificity, and accuracy. Pathologic analysis of the surgical resection served as the reference standard. The three modalities were compared for specificity and sensitivity with the McNemar test. Pathologic examination revealed 903 nodes, of which 89 were malignant. Of the malignant nodes, 43 were necrotic. Analysis of the detection of necrosis in the 89 malignant nodes showed an accuracy, sensitivity, and specificity of 92%, 91%, and 93% for CT; 91%, 93%, and 89% for MR imaging; and 85%, 77%, and 93% for US, respectively. All imaging modalities failed to depict necrotic areas of 3 mm or smaller in three nodes, and necrosis was missed in an additional seven nodes with US and in one node with CT. Necrosis could not be distinguished from other components of malignancy, such as viable tumor and scar tissue, in seven nodes (CT, 3; MR imaging, 5; US, 3). The sensitivity of both MR imaging and CT was significantly better than that of US (P =.0082 and P =.0339, respectively). There was no significant difference in sensitivity (P =.3173) between MR imaging and CT, or in the specificity of the three modalities. MR imaging is comparable to CT for the detection of necrosis. The sensitivity of MR imaging and CT is better than that of US.

1 February 2013 in Radiology
Verified
Journal Article
Closed access
AKAnn D. King
Ann D. King
KCKwok-Keung Chow
Kwok-Keung Chow
KYKwok-Hung Yu
Kwok-Hung Yu
FMFrankie Kwok Fai Mo
Frankie Kwok Fai Mo
DYDavid K. W. Yeung
David K. W. Yeung
AAAnil T. Ahuja
Anil T. Ahuja
Diffusion-weighted imaging of primary head and neck squamous cell carcinoma with apparent diffusion coefficient histogram analysis shows potential for predicting local failure within 2 years of treatment with chemotherapy and radiation therapy. PurposeTo determine the diagnostic performance of diffusion-weighted (DW) imaging for the prediction of treatment failure in primary head and neck squamous cell carcinoma (HNSCC).Materials and MethodsThe study was approved by the local institutional ethics committee and conducted with informed written consent in patients with primary HNSCC treated with radiation therapy and chemotherapy. DW imaging of the primary tumor was performed before treatment in 37 patients and was repeated within 2 weeks of treatment in 30 patients. Histograms of apparent diffusion coefficients (ADCs) were analyzed, and mean ADC, kurtosis, skewness, and their respective percentage change were correlated for local failure and local control at 2 years by using the Student t test. Univariate and multivariate analyses of the ADC parameters, T stage, and tumor volume were performed by using logistic regression for prediction of local failure.ResultsLocal failure occurred in 16 of 37 (43%) patients and local control occurred in 21 of 37...

23 March 2010 in European Radiology
Verified
Journal Article
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AKAnn D. King
Ann D. King
FMFrankie K. F. Mo
Frankie K. F. Mo
KYKwok-Hung Yu
Kwok-Hung Yu
DYDavid K. W. Yeung
David K. W. Yeung
HZHua Zhou
Hua Zhou
AAAnil T. Ahuja
Anil T. Ahuja

1 August 2008 in Current Cancer Drug Targets
Verified
Journal Article
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PDF file
George G ChenGeorge G Chen
George G Chen
AVAlexander Chris Vlantis
Alexander Chris Vlantis
QZQiang Zeng
Qiang Zeng
CHC. Andrew van Hasselt
C. Andrew van Hasselt
Thyroid cancer occurs three times more frequently in females than in males, and in females the incidence decreases after menopause. This gender difference suggests that the growth and progression of thyroid cancer may be influenced by female sex hormones, particularly estrogens. Experimental data have clearly demonstrated that estrogens can influence cancer cell growth. The action of estrogens on target sites is mediated through related but distinct estrogen receptors, designated estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), both of which are known to be expressed in thyroid cancer cells. The proliferation of thyroid cancer cells is promoted by an ERα agonist, whereas the proliferation is reduced by the enhanced expression of ERβ or by an ERβ agonist. When ERβ is down-regulated, the proliferation of thyroid cells is significantly increased. Studies have shown that the expression of ERα in thyroid cancer cells is increased while the expression of ERβ is either very low or absent. In conclusion, it appears that estrogens have opposite effects on the growth of thyroid cancer cells, depending on the balance between ERα and ERβ in the cells. The modulation of ERα and ERβ and the intervention of their pathways may open up new potential targets for the treatment of thyroid cancer.

1 February 2011 in Radiology
Verified
Journal Article
Closed access
AKAnn D. King
Ann D. King
AVAlexander Chris Vlantis
Alexander Chris Vlantis
KBKunwar S. S. Bhatia
Kunwar S. S. Bhatia
BZBenny Chung-Ying Zee
Benny Chung-Ying Zee
JWJohn K. S. Woo
John K. S. Woo
AAAnil T. Ahuja
Anil T. Ahuja
To compare the accuracy of magnetic resonance (MR) imaging with that of the current clinical standard of endoscopy and endoscopic biopsy, to determine whether MR imaging depicts subclinical cancers missed at endoscopy and endoscopic biopsy, and to determine whether MR imaging can identify patients without nasopharyngeal carcinoma (NPC) who do not need to undergo invasive sampling biopsy. The study protocol was approved by the institutional review board; written informed consent was obtained from all patients. Patients suspected of having NPC underwent MR imaging, endoscopy, and endoscopic biopsy. Endoscopic biopsy targeted the suspected tumor or sampled the endoscopically normal nasopharynx. The final diagnosis was based on results of the endoscopic biopsy or on results of a repeat biopsy directed at the lesion detected at MR imaging. The sensitivity and specificity of the three investigations were compared by using the Fisher exact test. NPC was present in 77 (31%) of 246 patients and absent in 169 (69%) patients. The combined sensitivity, specificity, and accuracy, respectively, were 100%, 93%, and 95% for MR imaging, 90%, 93%, and 92% for endoscopy, and 95%, 100%, and 98% for endoscopic biopsy. Benign disease was mistaken for NPC in 12 (7%) of 169 patients at MR imaging and in 11 (6%) patients at endoscopy. The sensitivity of MR imaging was significantly higher than that of endoscopy (P = .006) and was similar to that of endoscopic biopsy (P = .120). The specificity of MR imaging was similar to that of endoscopy (P = .120) and was significantly lower than that of endoscopic biopsy (P < .001). MR imaging is an accurate test for the diagnosis of NPC. MR imaging depicts subclinical cancers missed at endoscopy and endoscopic biopsy and helps identify the majority of patients who do not have NPC and who therefore do not need to undergo invasive sampling biopsies.

15 November 2007 in Cell Proliferation
Verified
Journal Article
Closed access
PDF file
QZQ. Zeng
Q. Zeng
George G ChenGeorge G Chen
George G Chen
AVAlexander Chris Vlantis
Alexander Chris Vlantis
CHC. A. Van Hasselt
C. A. Van Hasselt