In vivo recognition of vascular structures by near infra-red - - PowerPoint PPT Presentation

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In vivo recognition of vascular structures by near infra-red - - PowerPoint PPT Presentation

Nov 11, 2022 257 likes •501 views

In vivo recognition of vascular structures by near infra-red transillumination Valentina Bello, Elisabetta Bodo, Sara Pizzurro, Sabina Merlo Department of Electrical, Computer and Biomedical Engineering University of Pavia, Pavia, Italy

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In vivo recognition of vascular structures by near infra-red transillumination

Valentina Bello, Elisabetta Bodo, Sara Pizzurro, Sabina Merlo Department of Electrical, Computer and Biomedical Engineering University of Pavia, Pavia, Italy

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Background

Transillumination followed by diffused light observation ✓Easy method to obtain qualitative information on the internal structure of a relatively thin tissue section ✓Used for detecting pathological conditions as well as for identifying vein locations ✘Using visible light for transillumination, a dark environment is needed ✘Images or videos are usually not captured nor analyzed for biosignal detection

IMAGE DETECTOR

TISSUE UNDER TEST

LIGHT SOURCE

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GOAL

Design, assembling and testing of portable optoelectronic instrumental configurations to achieve efficient transillumination and image acquisition for in vivo tissue imaging and detection of time-dependent vital signs Illuminator versions: 7-LED probe / 36-VCSEL matrix, both lc= 850 nm CMOS camera with optical filters for image/video acquisition VCSEL: lower driving current and local optical power, negligible thermal effect ➜ LESS INVASIVE than LED Narrow band emission of VCSEL with narrow band detection ➜ better ambient light rejection

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NIR VCSEL Matrix (36) Tissue 5 cm 50 cm USB3.0 PC OPV 332

CMOS camera with lens and

  • ptical filters

LWP: lcut-on= 780 nm BP: lcenter= 850 nm B=10 nm

VCSEL Matrix driver

Image taken with all VCSELs ON

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PC

CMOS camera with lens and

  • ptical filters

VCSEL Matrix driver

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VCSELs OFF Subject 1 Left hand Subject 2 Right hand Subject 3 Right hand Subject 4 Left hand Subject 5 Right hand Subject 6 Right hand Subject 7 Right hand

FEMALE SUBJECTS MALE SUBJECTS

Dorsal venous network and dorsal venous arch of hand (Anastomosis)

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MATLAB processing of the videos:

  • video reading
  • selection of the region of interest (ROI)
  • elaboration of the grey value of each pixel of the ROI
  • gray level variation in time-domain
  • peripheral pressure wave in time-domain
  • extraction of the main spectral components of the signal:

cardiac frequency fHR and respiratory frequency fRR

FFT

M-PEG VIDEOS 1 min 85 fps

Software FlyCapture2

ROI

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MATLAB processing of the videos:

  • video reading
  • selection of the region of interest (ROI)
  • elaboration of the grey value of each pixel of the ROI
  • gray level variation in time-domain
  • peripheral pressure wave in time-domain
  • extraction of the main spectral components of the signal:

cardiac frequency fHR and respiratory frequency fRR

FFT

M-PEG VIDEOS 1 min 85 fps

Software FlyCapture2

ROI

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MATLAB processing of the videos:

  • video reading
  • selection of the region of interest (ROI)
  • elaboration of the grey value of each pixel of the ROI
  • gray level variation in time-domain
  • peripheral pressure wave in time-domain
  • extraction of the main spectral components of the signal:

cardiac frequency fHR and respiratory frequency fRR

FFT

M-PEG VIDEOS 1 min 85 fps

Software FlyCapture2

ROI

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HR: HEART RATE RR: RESPIRATORY RATE

FEMALE SUBJECTS

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fRR due to respiratory sinus arrhythmia

HR: HEART RATE RR: RESPIRATORY RATE

FEMALE SUBJECTS

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HR: HEART RATE RR: RESPIRATORY RATE

MALE SUBJECTS

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Subject 4 Left Hand ROI Raw image

MALE SUBJECT

Histogram

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Adjusted image Equalized image

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FEMALE SUBJECT

Subject 2 Wrist

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fRR=0.25Hz ➜15bpm fHR=1.084Hz ➜65bpm

MALE SUBJECT WITH DARK SKIN visible NIR VCSEL transillumination

2fHR 3fHR

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MALE SUBJECT WITH DARK SKIN

RAW image Adjusted image

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Fertilized chicken eggs under incubation

Vessels

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Morpho-functional imaging

ROI Raw image

VIDEO ACQUISITION: Movements of the embryo inside the eggshell

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Adjusted Histogram

Equalized Histogram

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CONCLUSIONS

Main features:

  • non-invasive method: it uses non-ionizing radiations
  • non-contact and remote analyses
  • during the test, no thermal or pressure stress or constraints
  • applicable on dark skinned subjects
  • works in normal ambient light conditions
  • morphological details with post-processing elaboration
  • save documentation

A VCSEL-based NIR transillumination system exploiting a portable

  • ptoelectronic instrumental configuration:

Successful diagnostic tool for morpho-functional imaging

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THANKS!