Alan Wang

Prof. Dr. Alan Wang

Auckland Bioengineering Institute, Faculty of Medical and Health Sciences, University of Auckland, Grafton, Auckland 1010, New Zealand
orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

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

Representative Publications

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17 January 2024 in Insights into Imaging
Verified
Journal Article
Open access
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BKBurak Kocak
Burak Kocak
TDTugba Akinci D'Antonoli
Tugba Akinci D'Antonoli
NMNathaniel Mercaldo
Nathaniel Mercaldo
AAAngel Alberich-Bayarri
Angel Alberich-Bayarri
BBBettina Baeßler
Bettina Baeßler
Renato CuocoloRenato Cuocolo
Renato Cuocolo
Purpose: To propose a new quality scoring tool, METhodological RadiomICs Score (METRICS), to assess and improve research quality of radiomics studies. Methods: We conducted an online modified Delphi study with a group of international experts. It was performed in three consecutive stages: Stage#1, item preparation; Stage#2, panel discussion among EuSoMII Auditing Group members to identify the items to be voted; and Stage#3, four rounds of the modified Delphi exercise by panelists to determine the items eligible for the METRICS and their weights. The consensus threshold was 75%. Based on the median ranks derived from expert panel opinion and their rank-sum based conversion to importance scores, the category and item weights were calculated. Result: In total, 59 panelists from 19 countries participated in selection and ranking of the items and categories. Final METRICS tool included 30 items within 9 categories. According to their weights, the categories were in descending order of importance: study design, imaging data, image processing and feature extraction, metrics and comparison, testing, feature processing, preparation for modeling, segmentation, and open science. A web application and a repository were developed to streamline the calculation of the METRICS score and to collect feedback from the radiomics community. Conclusion: In this work, we developed a scoring tool for assessing the methodological quality of the radiomics research, with a large international panel and a modified Delphi protocol. With its conditional format to cover methodological variations, it provides a well-constructed framework for the key methodological concepts to assess the quality of radiomic research papers. Critical relevance statement: A quality assessment tool, METhodological RadiomICs Score (METRICS), is made available by a large group of international domain experts, with transparent methodology, aiming at evaluating and improving research quality in radiomics and machine learning. Key points: • A methodological scoring tool, METRICS, was developed for assessing the quality of radiomics research, with a large international expert panel and a modified Delphi protocol. • The proposed scoring tool presents expert opinion-based importance weights of categories and items with a transparent methodology for the first time. • METRICS accounts for varying use cases, from handcrafted radiomics to entirely deep learning-based pipelines. • A web application has been developed to help with the calculation of the METRICS score (https://metricsscore.github.io/metrics/METRICS.html) and a repository created to collect feedback from the radiomics community (https://github.com/metricsscore/metrics). Graphical

24 March 2023 in Bioengineering
Verified
Journal Article
Open access
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FEFatemeh Esmaeili
Fatemeh Esmaeili
ECErica Cassie
Erica Cassie
HNHong Phan T. Nguyen
Hong Phan T. Nguyen
NPNatalie Olivia Victoria Plank
Natalie Olivia Victoria Plank
CUCharles Peter Unsworth
Charles Peter Unsworth
Alan WangAlan Wang
Alan Wang
Anomaly detection is a significant task in sensors’ signal processing since interpreting an abnormal signal can lead to making a high-risk decision in terms of sensors’ applications. Deep learning algorithms are effective tools for anomaly detection due to their capability to address imbalanced datasets. In this study, we took a semi-supervised learning approach, utilizing normal data for training the deep learning neural networks, in order to address the diverse and unknown features of anomalies. We developed autoencoder-based prediction models to automatically detect anomalous data recorded by three electrochemical aptasensors, with variations in the signals’ lengths for particular concentrations, analytes, and bioreceptors. Prediction models employed autoencoder networks and the kernel density estimation (KDE) method for finding the threshold to detect anomalies. Moreover, the autoencoder networks were vanilla, unidirectional long short-term memory (ULSTM), and bidirectional LSTM (BLSTM) autoencoders for the training stage of the prediction models. However, the decision-making was based on the result of these three networks and the integration of vanilla and LSTM networks’ results. The accuracy as a performance metric of anomaly prediction models showed that the performance of vanilla and integrated models were comparable, while the LSTM-based autoencoder models showed the least accuracy. Considering the integrated model of ULSTM and vanilla autoencoder, the accuracy for the dataset with the lengthier signals was approximately 80%, while it was 65% and 40% for the other datasets. The lowest accuracy belonged to the dataset with the least normal data in its dataset. These results demonstrate that the proposed vanilla and integrated models can automatically detect abnormal data when there is sufficient normal data for training the models.

22 January 2024 in Computers in Biology and Medicine
Verified
Journal Article
Closed access
LXLiangliang Xiang
Liangliang Xiang
Yaodong GuYaodong Gu
Yaodong Gu
ZGZixiang Gao
Zixiang Gao
PYPeimin Yu
Peimin Yu
VSVickie Shim
Vickie Shim
JFJustin Fernandez
Justin Fernandez

27 February 2025 in Medical Image Analysis
Verified
Journal Article
Open access
YLYinbin Lu
Yinbin Lu
Alan WangAlan Wang
Alan Wang
Vision-Language Models (VLMs) are regarded as efficient paradigms that build a bridge between visual perception and textual interpretation. For medical visual tasks, they can benefit from expert observation and physician knowledge extracted from textual context, thereby improving the visual understanding of models. Motivated by the fact that extensive medical reports are commonly attached to medical imaging, medical VLMs have triggered more and more interest, serving not only as self-supervised learning in the pretraining stage but also as a means to introduce auxiliary information into medical visual perception. To strengthen the understanding of such a promising direction, this survey aims to provide an in-depth exploration and review of medical VLMs for various visual recognition and reasoning tasks. Firstly, we present an introduction to medical VLMs. Then, we provide preliminaries and delve into how to exploit language in medical visual tasks from diverse perspectives. Further, we investigate publicly available VLM datasets and discuss the challenges and future perspectives. We expect that the comprehensive discussion about state-of-the-art medical VLMs will make researchers realize their significant potential.

12 September 2023 in Bioengineering
Verified
Journal Article
Open access
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JMJake McNaughton
Jake McNaughton
Justin FernandezJustin Fernandez
Justin Fernandez
SHSamantha Medical Research Holdsworth
Samantha Medical Research Holdsworth
BCBenjamin Chong
Benjamin Chong
VSVickie Shim
Vickie Shim
Alan WangAlan Wang
Alan Wang
Background: CT scans are often the first and only form of brain imaging that is performed to inform treatment plans for neurological patients due to its time- and cost-effective nature. However, MR images give a more detailed picture of tissue structure and characteristics and are more likely to pick up abnormalities and lesions. The purpose of this paper is to review studies which use deep learning methods to generate synthetic medical images of modalities such as MRI and CT. Methods: A literature search was performed in March 2023, and relevant articles were selected and analyzed. The year of publication, dataset size, input modality, synthesized modality, deep learning architecture, motivations, and evaluation methods were analyzed. Results: A total of 103 studies were included in this review, all of which were published since 2017. Of these, 74% of studies investigated MRI to CT synthesis, and the remaining studies investigated CT to MRI, Cross MRI, PET to CT, and MRI to PET. Additionally, 58% of studies were motivated by synthesizing CT scans from MRI to perform MRI-only radiation therapy. Other motivations included synthesizing scans to aid diagnosis and completing datasets by synthesizing missing scans. Conclusions: Considerably more research has been carried out on MRI to CT synthesis, despite CT to MRI synthesis yielding specific benefits. A limitation on medical image synthesis is that medical datasets, especially paired datasets of different modalities, are lacking in size and availability; it is therefore recommended that a global consortium be developed to obtain and make available more datasets for use. Finally, it is recommended that work be carried out to establish all uses of the synthesis of medical scans in clinical practice and discover which evaluation methods are suitable for assessing the synthesized images for these needs.

23 November 2023 in Bioengineering
Verified
Journal Article
Open access
PDF file
FEFatemeh Esmaeili
Fatemeh Esmaeili
ECErica Cassie
Erica Cassie
HNHong Phan T. Nguyen
Hong Phan T. Nguyen
NPNatalie Olivia Victoria Plank
Natalie Olivia Victoria Plank
CUCharles Peter Unsworth
Charles Peter Unsworth
Alan WangAlan Wang
Alan Wang
Nanomaterial-based aptasensors serve as useful instruments for detecting small biological entities. This work utilizes data gathered from three electrochemical aptamer-based sensors varying in receptors, analytes of interest, and lengths of signals. Our ultimate objective was the automatic detection and quantification of target analytes from a segment of the signal recorded by these sensors. Initially, we proposed a data augmentation method using conditional variational autoencoders to address data scarcity. Secondly, we employed recurrent-based networks for signal extrapolation, ensuring uniform signal lengths. In the third step, we developed seven deep learning classification models (GRU, unidirectional LSTM (ULSTM), bidirectional LSTM (BLSTM), ConvGRU, ConvULSTM, ConvBLSTM, and CNN) to identify and quantify specific analyte concentrations for six distinct classes, ranging from the absence of analyte to 10 μM. Finally, the second classification model was created to distinguish between abnormal and normal data segments, detect the presence or absence of analytes in the sample, and, if detected, identify the specific analyte and quantify its concentration. Evaluating the time series forecasting showed that the GRU-based network outperformed two other ULSTM and BLSTM networks. Regarding classification models, it turned out signal extrapolation was not effective in improving the classification performance. Comparing the role of the network architectures in classification performance, the result showed that hybrid networks, including both convolutional and recurrent layers and CNN networks, achieved 82% to 99% accuracy across all three datasets. Utilizing short-term Fourier transform (STFT) as the preprocessing technique improved the performance of all datasets with accuracies from 84% to 99%. These findings underscore the effectiveness of suitable data preprocessing methods in enhancing neural network performance, enabling automatic analyte identification and quantification from electrochemical aptasensor signals.