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Lasers Surg Med. 2015 Aug;47(6):520-5. doi: 10.1002/lsm.22370.

Fiber-based laser speckle imaging for the detection of pulsatile flow.

Author information

1
Beckman Laser Institute and Medical Clinic, University of California, Irvine, California, 92612.
2
Department of Biomedical Engineering, University of California, Irvine, California, 92697.
3
Optics Department, Instituto Nacional de Astrofísica, Óptica y Electrónica, Puebla, México, 72840.
4
Department of Surgery, University of California, Irvine Medical Center, Orange, California, 92868.
5
Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, California, 92697.

Abstract

BACKGROUND AND OBJECTIVE:

In endodontics, a major diagnostic challenge is the accurate assessment of pulp status. In this study, we designed and characterized a fiber-based laser speckle imaging system to study pulsatile blood flow in the tooth.

STUDY DESIGN/MATERIALS AND METHODS:

To take transilluminated laser speckle images of the teeth, we built a custom fiber-based probe. To assess our ability to detect changes in pulsatile flow, we performed in vitro and preliminary in vivo tests on tissue-simulating phantoms and human teeth. We imaged flow of intralipid in a glass microchannel at simulated heart rates ranging from 40 beats/minute (bpm) to 120 bpm (0.67-2.00 Hz). We also collected in vivo data from the upper front incisors of healthy subjects. From the measured raw speckle data, we calculated temporal speckle contrast versus time. With frequency-domain analysis, we identified the frequency components of the contrast waveforms.

RESULTS:

With our approach, we observed in vitro the presence of pulsatile flow at different simulated heart rates. We characterized simulated heart rate with an accuracy of and >98%. In the in vivo proof-of-principle experiment, we measured heart rates of 69, 90, and 57 bpm, which agreed with measurements of subject heart rate taken with a wearable, commercial pulse oximeter.

CONCLUSIONS:

We designed, built, and tested the performance of a dental imaging probe. Data from in vitro and in -vivo tests strongly suggest that this probe can detect the presence of pulsatile flow. LSI may enable endodontists to noninvasively assess pulpal vitality via direct measurement of blood flow.

KEYWORDS:

cold test; dental photoplethysmography; electric pulp test; endodontics; leached fiber bundle; pulpal vitality; pulsatile blood flow; root canal

PMID:
26202900
PMCID:
PMC4605827
DOI:
10.1002/lsm.22370
[Indexed for MEDLINE]
Free PMC Article

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