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385
result(s) for
"Yu, Simon C. H."
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Federated deep learning for detecting COVID-19 lung abnormalities in CT: a privacy-preserving multinational validation study
by
Dou, Qi
,
Yu, Kevin
,
Heng, Pheng Ann
in
692/53/2421
,
692/700/1421/1846/2771
,
Artificial intelligence
2021
Data privacy mechanisms are essential for rapidly scaling medical training databases to capture the heterogeneity of patient data distributions toward robust and generalizable machine learning systems. In the current COVID-19 pandemic, a major focus of artificial intelligence (AI) is interpreting chest CT, which can be readily used in the assessment and management of the disease. This paper demonstrates the feasibility of a federated learning method for detecting COVID-19 related CT abnormalities with external validation on patients from a multinational study. We recruited 132 patients from seven multinational different centers, with three internal hospitals from Hong Kong for training and testing, and four external, independent datasets from Mainland China and Germany, for validating model generalizability. We also conducted case studies on longitudinal scans for automated estimation of lesion burden for hospitalized COVID-19 patients. We explore the federated learning algorithms to develop a privacy-preserving AI model for COVID-19 medical image diagnosis with good generalization capability on unseen multinational datasets. Federated learning could provide an effective mechanism during pandemics to rapidly develop clinically useful AI across institutions and countries overcoming the burden of central aggregation of large amounts of sensitive data.
Journal Article
The association of liver function and quality of life of patients with liver cancer
2019
Background
Quality of life (QOL) assessments with the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30, QLQ-HCC18, C30 and HCC18 index scores have been shown to be prognostic factors for overall survival (OS) in patients with hepatocellular carcinoma (HCC), independent of disease stage and liver function. Liver function parameters (including bilirubin, albumin, international normalized ratio [INR], Child-Pugh class, ALBI grade, MELD, alkaline phosphatase [ALP]-to-platelet ratio, albumin-to-ALP ratio) have also been found to be independent prognostic factors for OS in HCC patients. There has been scanty data on whether QOL and baseline liver function per se are correlated in HCC patients. This study investigates the correlations between baseline QOL data and liver function variables in HCC patients.
Methods
From 2007 to 2011, 517 patients were enrolled. Baseline QOL was assessed at diagnosis using the EORTC QLQ-C30 and QLQ-HCC18; thereafter C30 and HCC18 index scores were derived. Clinical and laboratory data were collected. For liver function assessment, Child-Pugh class, ALBI grade, MELD, ALP-to-platelet ratio and albumin-to-ALP ratio were derived. Correlation analyses were performed between QOL and liver function data.
Results
Complete QOL data were available in 472 HCC patients. After adjusting for clinical variables, significant correlations were found between QOL (QLQ-C30 and QLQ-HCC18) and dichotomized liver function variables (including Child-Pugh class, ALBI grade and the presence of ascites). It was demonstrated that QOL had significant and potentially clinically important correlations with continuous liver function variables (albumin, bilirubin, ALP and albumin-to-ALP ratio), with the highest Spearman’s rank correlation coefficient (rho) exceeding 0.4. HCC18 and C30 index scores were also significantly correlated with these liver function variables. HCC18 index score, which had rho up to 0.37, generally performed better than C30 index score, which had rho up to 0.33.
Conclusions
In HCC patients, baseline QOL assessment (using EORTC QLQ-C30, QLQ-HCC18, C30 index-score or HCC18 index-score) is significantly correlated with liver function. Based on the findings of this study, future trials are warranted to assess whether treatment to enhance liver function could improve HCC patients’ QOL.
Journal Article
The Potential of Computational Fluid Dynamics Simulation on Serial Monitoring of Hemodynamic Change in Type B Aortic Dissection
by
Wong, Randolph H. L.
,
Underwood, Malcolm
,
Yu, Simon C. H.
in
Aneurysm, Dissecting - diagnostic imaging
,
Aneurysm, Dissecting - physiopathology
,
Aneurysm, Dissecting - surgery
2016
Purpose
We aimed to assess the potential of computational fluid dynamics simulation (CFD) in detecting changes in pressure and flow velocity in response to morphological changes in type B aortic dissection.
Materials and Methods
Pressure and velocity in four morphological models of type B aortic dissection before and after closure of the entry tear were calculated with CFD and analyzed for changes among the different scenarios. The control model (Model 1) was patient specific and built from the DICOM data of CTA, which bore one entry tear and three re-entry tears. Models 2–4 were modifications of Model 1, with two re-entry tears less in Model 2, one re-entry tear more in Model 3, and a larger entry tear in Model 4.
Results
The pressure and velocity pertaining to each of the morphological models were unique. Changes in pressure and velocity findings were accountable by the changes in morphological features of the different models. There was no blood flow in the false lumen across the entry tear after its closure, the blood flow direction across the re-entry tears was reversed after closure of the entry tear.
Conclusion
CFD simulation is probably useful to detect hemodynamic changes in the true and false lumens of type B aortic dissection in response to morphological changes, it may potentially be developed into a non-invasive and patient-specific tool for serial monitoring of hemodynamic changes of type B aortic dissection before and after treatment.
Journal Article
Phase I/II study of temsirolimus for patients with unresectable Hepatocellular Carcinoma (HCC)- a correlative study to explore potential biomarkers for response
2015
Background
The oncogenic PI3K/Akt/mTOR pathway is frequently activated in HCC. Data on the mTOR inhibitor, temsirolimus, is limited in HCC patients with concomitant chronic liver disease. The objectives of this study were: (1) In phase I, to determine DLTs and MTD of temsirolimus in HCC patients with chronic liver disease; (2) In phase II, to assess activity of temsirolimus in HCC, and (3) to explore potential biomarkers for response.
Methods
Major eligibility criteria included histologically confirmed advanced HCC and adequate organ function. In Phase I part of the study, temsirolimus was given weekly in 3-weekly cycle; dose levels were 20 mg (level 1), 25 mg (level 2) and 30 mg (level 3). The MTD was used in the subsequent phase II part; the primary endpoint was PFS and secondary endpoints were response and OS. In addition, exploratory analysis was conducted on pre-treatment tumour tissues to determine stathmin, pS6, pMTOR or p-AKT expressions as potential biomarkers for response. Overall survival and PFS were calculated using the Kaplan-Meier method. Reassessment CT scans were done every 6 weeks. All adverse events were reported using CTCAE v3.
Results
The Phase I part consisted of 19 patients, 2 of 6 patients at level 3 experienced DLT; dose level 2 was determined to be the MTD. The phase II part consisted of 36 patients. Amongst 35 assessable patients, there were 1 PR, 20 SD and 14 PD. Overall, the median PFS was 2.83 months (95% C.I. 1.63-5.24). The median OS was 8.89 months (95% C.I. 5.89-13.30). Grade ≥ 3 that occurred in > 10% of patients included thrombocytopenia (4) and hyponatraemia (4). Exploratory analysis revealed that disease stabilization (defined as CR + PR + SD > 12 weeks) in tumours having high and low pMTOR H-scores to be 70% and 29% respectively (OR 5.667, 95% CI 1.129-28.454, p = 0.035).
Conclusions
In HCC patients with chronic liver disease, the MTD of temsirolimus was 25 mg weekly in a 3-week cycle. The targeted PFS endpoint was not reached. However, further studies to identify appropriate patient subgroup are warranted.
Trial registration
This study has been registered in ClinicalTrials.gov (Id:
NCT00321594
) on 1 December 2010.
Journal Article
A phase II clinical study on the efficacy and predictive biomarker of pegylated recombinant arginase on hepatocellular carcinoma
2021
Background: Pegylated recombinant human arginase (PEG-BCT-100) is an arginine depleting drug. Preclinical studies showed that HCC is reliant on exogenous arginine for growth due to the under-expression of the arginine regenerating enzymes argininosuccinate synthetase (ASS) and ornithine transcarbamylase (OTC). Methods: This is a single arm open-label Phase II trial to assess the potential clinical efficacy of PEG-BCT-100 in chemo naïve sorafenib-failure HCC patients. Pre-treatment tumour biopsy was mandated for ASS and OTC expression by immunohistochemistry (IHC). Weekly intravenous PEG-BCT-100 at 2.7 mg/kg was given. Primary endpoint was time to progression (TTP); secondary endpoints included radiological response as per RECIST1.1, progression free survival (PFS) and overall survival (OS). Treatment outcomes were correlated with tumour immunohistochemical expressions of ASS and OTC. Results: In total 27 patients were recruited. The median TTP and PFS were both 6 weeks (95% CI, 5.9–6.0 weeks). The disease control rate (DCR) was 21.7% (5 stable disease). The drug was well tolerated. Post hoc analysis showed that duration of arginine depletion correlated with OS. For patients with available IHC results, 10 patients with ASS-negative tumour had OS of 35 weeks (95% CI: 8.3–78.0 weeks) vs. 15.14 weeks (95% CI: 13.4–15.1 weeks) in 3 with ASS-positive tumour; expression of OTC did not correlate with treatment outcomes. Conclusions: PEG-BCT-100 in chemo naïve post-sorafenib HCC is well tolerated with moderate DCR. ASS-negative confers OS advantage over ASS-positive HCC. ASS-negativity is a potential biomarker for OS in HCC and possibly for other ASS-negative arginine auxotrophic cancers. Trial registration number: NCT01092091. Date of registration: March 23, 2010.
Journal Article
A venographic operational classification for transvenous embolization of dural carotid-cavernous fistula
2011
Introduction
It is hypothesized that a venographic-based operational classification of dural carotid-cavernous fistula (DCCF) will facilitate early selection of the optimal venous route and enhance the efficacy of transvenous catheterization and embolization of the cavernous sinus.
Methods
This was a retrospective study on 97 patients who presented with symptomatic DCCF. Definition of classification type 1: both the anterior and posterior compartments of the cavernous sinus were opacified, type 2: only the anterior compartment was opacified, type 3: only the posterior compartment was opacified. Subtype a: the facial vein (FV) draining the superior ophthalmic vein (SOV) was opacified, subtype b: only the inferior petrosal sinus (IPS) was opacified, subtype c: neither the FV nor the IPS were opacified, subtype d: both the FV and the IPS were opacified. The SOV route was recommended for subtype 1a and type 2. The IPS route was recommended for subtype1b, 1c, 1d, and type 3. Success rates of catheterization by the recommended routes and non-recommended routes were calculated.
Results
Number of DCCF lesions were 20 (1a), 28 (1b), 23 (1c), 26 (1d), 16 (2a), 10 (2c), 2 (3b). Of 145 attempted catheterization, 91 and 54 were performed with a recommended route and un-recommended route, respectively. Success rate for catheterization and embolization performed with the recommended route and un-recommended route was 71/91 (78%) and 20/54 (37%), respectively (Chi-Square test
P
= 0.0024).
Conclusions
Venographic operational classification is useful for guiding the selection of optimal venous route which enhances the efficacy of transvenous embolization of the DCCF.
Journal Article
Biliary Complications Associated with Selective Internal Radiation (SIR) Therapy for Unresectable Liver Malignancies
by
Lai, Paul B. S.
,
Yu, Simon C. H.
,
Lau, W. Y.
in
Aged
,
Bacterial diseases
,
Bacterial diseases of the digestive system and abdomen
2008
Selective internal radiation (SIR) therapy using
90
yttrium microspheres is effective for treating selected cases of unresectable liver malignancies with little morbidity. We herein report two cases illustrating a very rare complication of SIR. A 68-year-old patient with inoperable recurrent hepatocellular carcinoma received one treatment of SIR with
90
yttrium microspheres and 4 months later presented with obstructive jaundice. Percutaneous transhepatic cholangiography revealed diffusely dilated intrahepatic ducts with multiple biliary strictures. Hepatic angiography showed normal hepatic arterial branches with no evidence of vascular insufficiency. Liver biopsy finally revealed cholestasis, cholangitis, and fibrosis, consistent with radiation-induced damage. Another 56-year-old patient with unresectable colorectal liver metastases presented with cholangitis 4 weeks after SIR. Ultrasonography showed no biliary dilatation, and endoscopic retrograde cholangiopancreatography demonstrated a normal biliary tree. Liver biopsy subsequently confirmed radiation-induced cholangitis.
Journal Article
Correlations of health-related quality of life with serum inflammatory indicators IL-8 and mIBI in patients with hepatocellular carcinoma
2019
Health-related quality of life (HRQoL) is a significant prognostic factor for overall survival in hepatocellular carcinoma (HCC) patients, and this is independent of stage and liver function. Inflammation plays a significant role in HCC development and progression. It was hypothesized that the inflammatory status of HCC patients may affect their HRQoL. The relationship between HRQoL and inflammatory status was explored using indicators IL-8 level and modified inflammation-based index (mIBI, based on IL-8, C-reactive protein, and albumin).
From 2007-2011, HCC patients were enrolled prospectively. Baseline HRQoL assessment utilized the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and QLQ-HCC18; clinical and laboratory data were collected at diagnosis. Two summary indices, C30 and HCC18 index-scores, were calculated. Correlation analyses were performed between HRQoL and inflammatory markers.
In the 445 patients studied, significant correlations were found between IL-8 levels and EORTC QLQ-C30, QLQ-HCC18, C30, and HCC18 index-scores. The strongest correlated factors were those reflective of constitutional symptoms, namely QLQ-C30 \"appetite loss\" (with Pearson's correlation coefficient,
=0.322,
<0.0001); QLQ-C30 \"fatigue\" (
=0.311,
<0.0001); QLQ-C30 \"role functioning\" (
=-0.305,
<0.0001); QLQ-HCC18 \"nutrition\" (
=0.317,
<0.0001); and QLQ-HCC18 \"fatigue\" (
=0.306,
<0.0001). In addition, moderate but significant correlations were also observed with HCC18 index score (
=0.321,
<0.0001), and C30 index score (
=0.306,
<0.0001). HRQoL factors were also significantly correlated with mIBI.
Baseline HRQoL using the conventional assessments of EORTC QLQ-C30 and QLQ-HCC18, as well as C30 and HCC18 index-scores, significantly correlated with inflammatory indicators (IL-8 level and mIBI) in HCC patients. Among the strongest correlations were those between IL-8 level and the two index-scores, as well as HRQoL aspects that represent constitutional symptoms. When paralleled with molecular findings, traditional HRQoL assessment in HCC has gained a new level of understanding: pattern recognition within an HRQoL instrument could potentially identify patients with more severe inflammatory state.
Journal Article
Plaque morphology in acute symptomatic intracranial atherosclerotic disease
2021
BackgroundIntracranial atherosclerotic disease (ICAD) is globally a major ischaemic stroke subtype with high recurrence. Understanding the morphology of symptomatic ICAD plaques, largely unknown by far, may help identify vulnerable lesions prone to relapse.MethodsWe prospectively recruited patients with acute ischaemic stroke or transient ischaemic attack attributed to high-grade ICAD (60%–99% stenosis). Plaque morphological parameters were assessed in three-dimensional rotational angiography, including surface contour, luminal stenosis, plaque length/thickness, upstream shoulder angulation, axial/longitudinal plaque distribution and presence of adjoining branch atheromatous disease (BAD). We compared morphological features of smooth, irregular and ulcerative plaques and correlated them with cerebral ischaemic lesion load downstream in MRI.ResultsAmong 180 recruited patients (median age=60 years; 63.3% male; median stenosis=75%), plaque contour was smooth (51 (28.3%)), irregular (101 (56.1%)) or ulcerative (28 (15.6%)). Surface ulcers were mostly at proximal (46.4%) and middle one-third (35.7%) of the lesions. Most (84.4%) plaques were eccentric, and half had their maximum thickness over the distal end. Ulcerative lesions were thicker (medians 1.6 vs 1.3 mm; p=0.003), had steeper upstream shoulder angulation (56.2° vs 31.0°; p<0.001) and more adjoining BAD (83.3% vs 57.0%; p=0.033) than non-ulcerative plaques. Ulcerative plaques were significantly associated with coexisting acute and chronic infarcts downstream (35.7% vs 12.5%; adjusted OR 4.29, 95% CI 1.65 to 11.14, p=0.003). Sensitivity analyses in patients with anterior-circulation ICAD lesions showed similar results in the associations between the plaque types and infarct load.ConclusionsUlcerative intracranial atherosclerotic plaques were associated with vulnerable morphological features and had a higher cumulative infarct load downstream.
Journal Article