Detecting intracranial hemorrhages using nearinfrared spectroscopy

1
Detecting intracranial hemorrhages using
near-infrared spectroscopy

• David J. Link
• Analytical/Radio/Nuclear (ARN) Seminar
• Spring 2008

2
Overview

• Importance and relevance
• Current non-invasive methods
• Near Infrared Spectroscopy (NIRS)
• Hematomas and Hemorrhages
• CRAINSCAN design
• Experimental Design
• Other Studies
• Conclusion

3
Importance

• Rapid detection of intracerebral hematomas
  drastically improves the chance of survival
• Rapid and reliable diagnosis enables caretakers
  to take immediate action
• 15 of patients admitted to emergency departments
  have intracranial bleeding
• 3 need immediate neurosurgical intervention

4
Current Method of Choice

• Computed tomography (CT)

• Positives
• Sensitivity and specificity nearing 100
• Non-invasive
• Negatives
• Not always immediately available
• Needs specific technicians and neurosurgical
  consultants (not always available)

Frank, J. W. Introduction to imaging Ionizing
radiation studentBMJ 200311349-392.
5
Other non-Invasive Methods

• Trans-cranial Doppler Ultrasonography (TCD)
• 2 MHz pulsed signal transmitted through the skull
• Doppler shift principle to measure red cell flow
  velocity (FV)
• Used for deeper brain injuries
• Near Infrared Spectroscopy (NIRS)
• Based on NIR light passing through skin and bone
  easily
• Absorption proportional to concentration of
  certain chromophores (Fe in hemoglobin and Cu in
  cytochrome aa3)

6
NIRS History

• Wilbur Kay with Beckman Instruments
• mid-1950s
• Di- and tri-atomic molecules from group theory
  and selection rules
• Perkin-Elmer and Cary
• Combining with visible
• USDA/ARS National NIR Research Project
• World wide network of collaborating laboratories
• Created International Official Methods

7
Near-Infrared Spectroscopy (NIRS)

• Electromagnetic Spectrum

Image taken from UNBC GIS LAB, Natural Hazards
Remote Sensing http//www.gis.unbc.ca/resources/g
eog100b.php
8
Infrared Spectral Regions
Table adapted from Principles of Instrumental
Analysis by Skoog, Holler and Nieman, 5th Edition.
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Vibrational Spectroscopy

• Hookes Law
• Two body harmonic oscillator
• NIR comprises combination bands and overtones
• If the world was simple multiples would work
• Life is not simple!

10
Franck-Condon Principle

• Classical
• Electronic transitions are very fast
• Vibrational levels corresponding to minimal
  changes in the nuclear coordinates favored
• Semi-classical
• P 1/v
• As v approaches 0, P approaches infinity

http//commons.wikimedia.org/wiki/ImageFranck-Con
don-diagram.png
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NIRS Instrumentation

• Sources
• Incandescent lamps
• Quartz halogen lamps
• LEDs
• Detectors
• Silicon-based CCDs
• InGaAs photodiodes
• PbS photoconductive detectors

12
NIRS Instrumentation Types

• Dispersive Infrared Instruments
• Emerged in the 1940s
• Designed for organic compounds
• Fourier Transform Infrared Spectrometer (FT-IR)
• Developed for commercial use in the 1960s
• Became common once computers caught up
• Portable and specific application devices
• Using specific wavelengths with laser diodes or
  filtered detectors

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FT-IR Principles

• Uses interferometer system

http//www.thermo.com/eThermo/CMA/PDFs/Product/pro
ductPDF_21615.pdf
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FT-IR Interference Patterns
A
B
C

• Two wavelength
• Multiple wavelengths
• Infrared Interferogram

http//www.thermo.com/eThermo/CMA/PDFs/Product/pro
ductPDF_21615.pdf
15
FT-IR Spectra Acquisition
http//www.thermo.com/eThermo/CMA/PDFs/Product/pro
ductPDF_21615.pdf
16
Dispersive Infrared

• Grating to create monochromatic detection
• Scan over all wavelengths by rotating grating
• Exit slit small enough for high precision

http//www.thermo.com/eThermo/CMA/PDFs/Product/pro
ductPDF_21615.pdf
17
NIRS Example Spectrum
Example NIRS transmission spectrum of caffeine
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Chemometrics

• Principal Component Analysis (PCA)
• Axis transformation to variance
• Cluster analysis
• Regression analysis

• Partial Least Square Regression (PLSR)
• Linear model
• Describes predictable variables in terms of
  observable variables
• Linear uses and not cluster

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Pros and Cons of NIRS

• Positives

• Negatives

• Highly unique spectra
• Non-destructive
• Rapid
• Nearly all organic molecules will interact
• Great for comparative analysis

• Structure determination
• Heavy data processing
• Peak heights and Beer-Lamberts law
• Interferences from water

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NIRS Applications

• Pharmaceutical
• Quality control and diagnostics
• Medical Diagnostics
• Blood sugar and oximetry
• Food and Agrochemical
• Quality control
• Combustion Research

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Terminology

• Hemorrhage
• Bleeding/ loss of blood from the circulatory
  system
• Intracranial Hemorrhage
• Bleeding within the skull
• Hematoma
• Blood tumor
• Caused by damage to blood vessel in turn causing
  blood to collect under the skin

22
Subdural and Epidural
Epidural
Subdural
http//www.octc.kctcs.edu/gcaplan/anat/Notes/API2
0Notes20L20Central20Nervous20System-Brain.htm
23
Glasgow Coma Scale

• Reliable, objective way of recording the
  conscious state of a person

Recreated from Teasdale G, Jennett B. Assessment
of coma and impaired consciousness. A practical
scale. Lancet 1974,281-84.
24
Clinical Trial

• Key Information
• B. Kessel, I. Jeroukhimov, I. Ashkenazi et. Al.
• This study was funded by Thomas Thomas Medical
  Marketing, representing Odicrain GmbH in Israel.
  Funders were not involved in the study design,
  data collection, analysis or interpretation of
  data, the writing of the manuscript or the
  decision to submit the manuscript for
  publication.
• Published International Journal of the Care of
  the Injured in 2007

25
Experimental Design

• Two Clinics
• Patients admitted
• If mandated head CT/Glasgow Coma score lt15
• Children under 18 and pregnant women were omitted
• Optical Density
• Instrument penetrates 3-4 cm deep
• Difference between each hemi-cranium gt 0.45
  considered significant inferring a hematoma
• CT following NIRS and CT used as control

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Detection Principle
Photo receiver

• Measurement of the optical density of tissue
• Device contains a laser source and a neighboring
  photo-receiver which are both pressed
  simultaneously to the patients head

Laser source
http//www.opticaldiagnosticsystems.com/
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Device Specifications

• Diode Laser
• 785 nm
• Class I laser
• Under 25mW
• Detector
• Photo-receiving transducer
• Counts radiant photons
• Voltage is proportional to incident radiation

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Detection Principle (cont.)

• Schematic Drawing

• CT Image

http//www.opticaldiagnosticsystems.com/training.p
df
http//www.opticaldiagnosticsystems.com/training.p
df
29
Detection Principle (cont.)
Figures recreated from CRAINSCAN website
http//www.opticaldiagnosticssystmes.com
30
Results

• 12 month long study
• 110 patients enrolled (64 men, 46 women)
• Mean GCS was 12.6 (range 3-15)
• 21 cases of epidural or subdural hematoma were
  found

Recreated from B. Kessel, I. Jeroukhimov, I.
Ashkenazi et. Al. Early detection of
life-threatening intracranial haemorrhage using a
portable near-infrared spectroscopy device. J.
Care Injured 2007381065-1068.
31
Results (cont.)

• NIRS outcome
• Sensitivity 90.5
• Specificity 95.5
• Positive predictive value 82.6
• Negative predictive value 97.7
• CT as Control
• Sensitivity and Specificity nearing 100

32
Other Similar Studies

• Kahraman S, et al.
• "The accuracy of near-infrared spectroscopy in
  detection of subdural and epidural hematomas" J.
  Trauma 2006
• Sensitivity 87
• Goldberg S. et al.
• "Near-infrared spectroscopy (NIRS) as a
  diagnostic tool in patients with suspected stroke
  or traumatic brain injury" Diagnostic Optical
  Spectroscopy in Biomedicine. 2001
• Stroke Sensitivity-65 and specificity-87
• Hematomas Sensitivity-98 and specificity-100

33
Conclusion

• NIRS does have many advantages
• NIRS can be used for rapid and reliable detection
  of both epidural and subdural hematomas
• Has not been shown to effectively differentiate
  epidural and subdural hematomas
• Portable device gives great versatility
• What if hematoma in both hemispheres?
• Portable NIRS should not and will not replace a
  CT scan

34
References

• B. Kessel, I. Jeroukhimov, I. Ashkenazi et. Al.
  Early detection of life-threatening intracranial
  haemorrhage using a portable near-infrared
  spectroscopy device. J. Care Injured
  2007381065-1068.
• Frank, J. W. Introduction to imaging Ionizing
  radiation. studentBMJ 200311349-392.
• Gopinath SP, Robertson CS, Contant CF, et al.
  Early detection of delayed traumatic intracranial
  hematomas using near-infrared spectroscopy. J
  Neurosurg 199583438-44.
• Gupta AK. Monitoring the injured brain in the
  intensive care unit. J Postgrad Med
  200248218-25.

35
Thanks!

• Analytical Spectroscopy Research Group
• Dr. Robert Lodder
• Thaddaeus Hannel
• Joshua Butcher
• Bala Sandeep Guddety
• University of Kentucky
• You for listening!