Acoustic resolution photoacoustic Doppler flowmetry for assessment of patient rectal cancer blood perfusion

Sep 21, 2026

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Photoacoustic Doppler flowmetry provides quantitative blood perfusion information alongside photoacoustic vascular contrast for rectal cancer evaluation. The study develops and validates a correlational Doppler flowmetry using an acoustic resolution photoacoustic microscopy (AR-PAM) system. The approach extracts perfusion by signal filtering and conditioning, A-line correlation, and angle compensation, supported by flow phantoms and contrast agents. The method is applied to in vivo post-treatment AR-PAM images to evaluate response and differentiate residual cancer, tumor bed tissue, and normal rectal tissue.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages11

Reading Time28 min

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Abstract

Introduction

Clinical motivation for rectal cancer assessment

Photoacoustic imaging and AR-PAM/US system context

Existing Doppler flowmetry approaches and limitations

Study direction and quantitative Doppler algorithm

RESEARCH PAPER Acoustic resolution photoacoustic Doppler flowmetry for assessment of patient rectal cancer blood perfusion Sitai Kou ,a Xiandong Leng,a Hongbo Luo,b Haolin Nie,a and Quing Zhua,b,c,* aWashington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States bWashington University in St. Louis, Department of Electrical and System Engineering, St. Louis, Missouri, United States cWashington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States | ABSTRACT. Significance: Photoacoustic Doppler flowmetry offers quantitative blood perfusion information in addition to photoacoustic vascular contrast for rectal cancer assessment.
Aim: We aim to develop and validate a correlational Doppler flowmetry utilizing an acoustic resolution photoacoustic microscopy (AR-PAM) system for blood perfusion analysis.
Approach: To extract blood perfusion information, we implemented AR-PAM Doppler flowmetry consisting of signal filtering and conditioning, A-line correlation, and angle compensation. We developed flow phantoms and contrast agent to systemically investigate the flowmetry’s efficacy in a series of phantom studies. The developed correlational Doppler flowmetry was applied to images collected during in vivo AR-PAM for post-treatment rectal cancer evaluation.
Results: The linearity and accuracy of the Doppler flow measurement system were validated in phantom studies. Imaging rectal cancer patients treated with chemoradiation demonstrated the feasibility of using correlational Doppler flowmetry to assess treatment response and distinguish residual cancer from cancer-free tumor bed tissue and normal rectal tissue.
Conclusions: A new correlational Doppler flowmetry was developed and validated through systematic phantom evaluations. The results of its application to in vivo patients suggest it could be a useful addition to photoacoustic endoscopy for post-treatment rectal cancer assessment.
© The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. [DOI: 10.1117/1.JBO.29.S1.S11517]
Keywords: acoustic resolution photoacoustic microscopy; photoacoustic Doppler flowmetry; ultrasound; rectal cancer; endoscopy
Paper 230277SSR received Sep. 18, 2023; revised Dec. 18, 2023; accepted Dec. 21, 2023; published Jan.
13, 2024 . | | --- | | 1 Introduction
Rectal cancer is prevalent in the United States, with an estimated 43,340 new cases in 2020, and the incidence rate among people 50 and younger has been increasing for the past decade.1 Rectal cancer requires complex care coordinated among surgeons, oncologists, and radiation specialists to achieve the highest survival rate. In recent years, clinical trials have investigated a nonoperative strategy called “watch and wait,” which allows patients with complete clinical | *Address all correspondence to Quing Zhu, [zhu.q@wustl.edu](zhu.q@wustl.edu) Journal of Biomedical Optics S11517-1 Vol. 29(S1) Kou et al.: Acoustic resolution photoacoustic Doppler flowmetry. . . responses to treatment to avoid surgical rectal resection and still achieve good long-term oncologic and functional outcomes.2,3 “Watch and wait” has gained tremendous interest, particularly among patients wishing to avoid often highly morbid rectal surgery. However, the strategy relies on accurate assessment of tumor regression and confident identification of patients with a pathological complete response (pCR), i.e., no residual tumors. Current assessment tools include digital rectal examination, endoscopy with biopsy, and functional MRI (fMRI) . Unfortunately, none of these modalities is particularly sensitive to residual tumor in the post-treatment rectum.4–6 Photoacoustic imaging (PAI) is a promising functional imaging technique that offers tu

FAQs

What is the goal of the correlational Doppler flowmetry in this study?

To develop and validate a correlational Doppler flowmetry that extracts blood perfusion information from an AR-PAM system for assessing rectal cancer.

How does the proposed AR-PAM Doppler flowmetry obtain flow information?

It uses signal filtering and conditioning, A-line correlation, and angle compensation to convert AR-PAM signals into blood perfusion flowmetry information.

What evidence supports the method’s performance?

Linearity and measurement accuracy were validated through phantom studies, and feasibility was demonstrated in in vivo images from rectal cancer patients after chemoradiation.

Sep 21, 2026

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