U.S. patent application number 11/537123 was filed with the patent office on 2007-05-31 for method and apparatus for method for viewing and analyzing of one or more biological samples with progressively increasing resolutions.
This patent application is currently assigned to The General Hospital Corporation. Invention is credited to Brett Eugene Bouma, Melissa Suter, Guillermo J. Tearney, Benjamin J. Vakoc, Dvir Yelin.
Application Number | 20070121196 11/537123 |
Document ID | / |
Family ID | 37533302 |
Filed Date | 2007-05-31 |
United States Patent
Application |
20070121196 |
Kind Code |
A1 |
Tearney; Guillermo J. ; et
al. |
May 31, 2007 |
METHOD AND APPARATUS FOR METHOD FOR VIEWING AND ANALYZING OF ONE OR
MORE BIOLOGICAL SAMPLES WITH PROGRESSIVELY INCREASING
RESOLUTIONS
Abstract
Method, apparatus and arrangement according an exemplary
embodiment of the present invention can be provided for analyzing
and/or illustrating at least one portion of an anatomical
structure. For example, light can be forwarded to such portion so
as to generate first information which is related to the portion.
For example, the light can be provided on or within a subject. The
first information can be received, and at least one section of the
portion may be selected based on the first information so as to
generate second information. A magnification of a display of the
portion may be progressively modified as a function of the second
information.
Inventors: |
Tearney; Guillermo J.;
(Cambridge, MA) ; Yelin; Dvir; (Brookline, MA)
; Vakoc; Benjamin J.; (Cambridge, MA) ; Suter;
Melissa; (Boston, MA) ; Bouma; Brett Eugene;
(Quincy, MA) |
Correspondence
Address: |
DORSEY & WHITNEY LLP;INTELLECTUAL PROPERTY DEPARTMENT
250 PARK AVENUE
NEW YORK
NY
10177
US
|
Assignee: |
The General Hospital
Corporation
Boston
MA
|
Family ID: |
37533302 |
Appl. No.: |
11/537123 |
Filed: |
September 29, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60721802 |
Sep 29, 2005 |
|
|
|
Current U.S.
Class: |
359/333 ;
600/407 |
Current CPC
Class: |
G01N 21/6486 20130101;
G01N 21/25 20130101; G01B 9/02 20130101; G02B 21/0028 20130101;
G01B 9/02027 20130101; G01B 9/02064 20130101; A61B 5/0068 20130101;
A61B 5/0075 20130101; A61B 5/6852 20130101; G01N 21/27 20130101;
G01N 23/046 20130101; A61B 5/0073 20130101; G02B 23/2461 20130101;
A61B 5/0062 20130101; G01B 9/02091 20130101; G01N 2223/419
20130101; G01B 9/04 20130101; G02B 23/2423 20130101; G01N 2021/1765
20130101; A61B 5/0066 20130101; G02B 23/2476 20130101; G01B 9/02049
20130101; G01N 21/6458 20130101; G01N 33/4833 20130101; G02B 23/243
20130101; A61B 5/0084 20130101; G01B 9/02087 20130101; G01N 21/4795
20130101 |
Class at
Publication: |
359/333 ;
600/407 |
International
Class: |
H01S 3/00 20060101
H01S003/00 |
Claims
1. A method for at least one of analyzing or illustrating at least
one portion of an anatomical structure, comprising: forwarding
light to the at least one portion so as to generate first
information which is related to the at least one portion, wherein
the light is provided on or within a subject; receiving the first
information, and selecting at least one section of the at least one
portion based on the first information so as to generate second
information; and progressively modifying a magnification of a
display of the at least one portion as a function of the second
information.
2. The method according to claim 1, wherein the modifying step
comprises modifying a display of a position of the at least one
portion.
3. The method according to claim 1, wherein the modifying step
comprises modifying a display of a depth of the at least one
portion within the anatomical structure.
4. The method according to claim 1, wherein the second information
is associated with a region provided within the at least one
portion.
5. The method according to claim 1, wherein the second information
is obtained by user-selecting the region.
6. The method according to claim 1, wherein the selecting step is
automatically performed by a processing arrangement without an
input from a user.
7. The method according to claim 1, further comprising determining
an area of an abnormality within the at least one portion, and
wherein the processing arrangement performs the selecting and
modifying steps so as to display at least one section of the
abnormality.
8. The method according to claim 1, further comprising determining
an area of an abnormality within the at least one portion using a
processing arrangement so as to generate third information, and
wherein the selecting step is performed by a user as a function of
the third information.
9. The method according to claim 1, further comprising determining
an area of an abnormality within the at least one portion using a
processing arrangement so as to generate third information, and
wherein the selecting step is performed by the processing
arrangement as a function of the third information.
10. The method according to claim 1, wherein the first information
is associated with a two-dimensional representation of the at least
one portion.
11. The method according to claim 1, wherein the first information
is associated with a three-dimensional representation of the at
least one portion.
12. The method according to claim 1, wherein the first information
is associated with a representation of the at least one portion
which has more than three dimensions.
13. The method according to claim 1, wherein the at least one
portion has an area that is greater than 1 mm.sup.2.
14. The method according to claim 1, wherein the at least one
portion has an area that is greater than 10 mm.sup.2.
15. The method according to claim 1, wherein a displayed section of
the at least one portion has an area is less than 1 cm.sup.2.
16. The method according to claim 1, wherein a displayed section of
the at least one portion has an area is less than 1 mm.sup.2.
17. The method according to claim 1, wherein a displayed section of
the at least one portion has an area is less than 100
.mu.m.sup.2.
18. The method according to claim 1, wherein the first information
is associated with at least one of: a confocal microscopy
procedure, a spectrally-encoded confocal microscopy procedure, an
optical coherence tomography procedure, and an optical frequency
domain interferometry procedure.
19. The method according to claim 1, further comprising providing
an arrangement within the anatomical structure so as to provide the
light to the at least one portion.
20. An apparatus for at least one of analyzing or illustrating at
least one portion of an anatomical structure, comprising: at least
one first arrangement which is configured to forward light to the
at least one portion so as to generate first information which is
related to the at least one portion; at least one second
arrangement which is configured to receive the first information,
and select at least one section of the at least one portion based
on the first information so as to generate second information; and
at least one third arrangement which is configured to progressively
modify a magnification of a display of the at least one portion as
a function of the second information.
21. An arrangement for at least one of analyzing or illustrating at
least one portion of an anatomical structure, comprising: a first
set of instructions which, when executed by a processing
arrangement, configures the processing arrangement to receive first
information which is related to the at least one portion generated
in response to light being forwarded to the at least one portion; a
second set of instructions which, when executed by the processing
arrangement, configures the processing arrangement to receive the
first information, and allows at least one of the processing
arrangement or a user to select at least one section of the at
least one portion based on the first information so as to generate
second information; and a third set of instructions which, when
executed by the processing arrangement, configures the processing
arrangement to progressively modify a magnification of a display of
the at least one portion as a function of the second information.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is based upon and claims the benefit of
priority from U.S. Patent Application Ser. No. 60/721,802, filed
Sep. 29, 2005, the entire disclosure of which is incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to relates to methods and
arrangement for viewing and analyzing of one or more biological
samples and anatomic structures with progressively increasing
resolutions.
BACKGROUND OF THE INVENTION
[0003] Radiological techniques such as X-ray computed tomography
("CT"), magnetic resonance imaging ("MRI"), and ultrasound can
enable noninvasive visualization of human pathology at the organ
level. Although these modalities may be capable of identifying
large-scale pathology, the diagnosis of cancer can require the
evaluation of microscopic structures that is beyond the resolution
of conventional imaging techniques. Consequently, biopsy and
histopathologic examination may be required for diagnosis. Because
precancerous growth and early stage cancers often arise on a
microscopic scale, they can present significant challenges for
identification and diagnosis. Conventional screening and
surveillance of these pathologies relies on unguided biopsy and
morphological analysis of Hematoxylin and Eosin ("H&E") stained
slides. Although this approach may be regarded as a current
standard for microscopic diagnosis, it requires the removal of
tissue from the patient and significant processing time to generate
slides. More importantly, histopathology is inherently a point
sampling technique; frequently only a very small fraction of the
diseased tissue can be excised and often less than 1% of a biopsy
sample may be examined by a pathologist.
[0004] It may be preferable to obtain microscopic diagnoses from an
entire organ or biological system in a living human patient.
However, the lack of an appropriate imaging technology can greatly
limits options for screening for pre-neoplastic conditions (e.g.
metaplasia) and dysplasia. In addition, an inability to identify
areas of dysplasia and carcinoma in situ has led to screening
procedures such as, e.g., random biopsy of the prostate, colon,
esophagus, and bladder, etc., which can be highly undesirable and
indiscriminate. Many diagnostic tasks presently referred to a
frozen section laboratory, such as the delineation of surgical
tumor margins, could be improved by a diagnostic modality capable
of rapidly imaging large tissue volumes on a microscopic scale. A
technology that could fill this gap between pathology and radiology
would be of great benefit to patient management and health
care.
[0005] Technical advances have been made to increase the resolution
of non-invasive imaging techniques such as, e.g., micro-CT,
micro-PET, and magnetic resonance imaging ("MRI") microscopy.
Resolutions approaching 20 .mu.m have been achieved by these
technologies, but fundamental physical limitations can still
prevent their application in patients. Microscopic optical biopsy
techniques, performed in situ, have recently been advanced for
non-excisional histopathologic diagnosis. Reflectance confocal
microscopy ("RCM") may be particularly well-suited for non-invasive
microscopy in patients, as it is capable of measuring microscopic
structure without tissue contact and does not require the
administration of extrinsic contrast agents. RCM can reject out of
focus light and detects backscattered photons selectively
originating from a single plane within the tissue. RCM can be
implemented, e.g., by rapidly scanning a focused beam of
electromagnetic radiation in a plane parallel to a tissue surface,
yielding transverse or en face images of tissue. The large
numerical aperture (NA) that may be used in RCM can yield a very
high spatial resolution (1-2 .mu.m), enabling visualization of
subcellular structures. High NA imaging, however, can be
particularly sensitive to aberrations that arise as light
propagates through inhomogeneous tissue. Also, high-resolution
imaging with RCM is typically limited to a depth of about 100-400
.mu.m.
[0006] RCM has been extensively demonstrated as a viable imaging
technique for skin tissue. Development of endoscopic confocal
microscopy systems has been more difficult, owing at least in part
to the substantial technical challenges involved in miniaturizing a
scanning microscope. One major obstacle to direct application of
the concepts of confocal microscopy to endoscopy is the engineering
of a mechanism for rapidly rastering a focused beam at the distal
end of a small-diameter, flexible probe. A variety of approaches
have been proposed to address this problem, including the use of
distal micro-electromechanical systems ("MEMS") beam scanning
devices and proximal scanning of single-mode fiber bundles. Also,
RCM may provide microscopic images only at discrete locations--a
"point sampling" technique. As currently implemented, point
sampling can be inherent to RCM because it has a limited field of
view, which may be comparable to or less than that of an excisional
biopsy, and the imaging rate can be too slow for comprehensive
large field microscopy.
[0007] Another challenge in adapting confocal microscopy to
endoscopic applications can include miniaturization of high NA
objectives that may be used for optical sectioning. Such
miniaturization may be achieved by providing, e.g., a
gradient-index lens system, dual-axis objectives, or custom designs
of miniature objectives. For example, detailed images of the
morphology of cervical epithelium may be obtained in vivo using a
fiber optic bundle coupled to a miniature objective lens, and
fluorescence-based images of colorectal lesions may be achieved
using commercial instruments such as those which may be obtained,
e.g., from Olympus Corp. and Pentax/Optiscan.
[0008] Despite these advances, there may be a need to provide
methods and arrangement that can parse data (e.g., provided either
at the cellular level, architectural level or both that can be
obtained from large surface areas or even possibly entire organs)
so that it may be appropriately interpreted in a timely, accurate
manner. Indeed, the amount of this data can be large and difficult
to view at one time such data, and thus such methods and
arrangements would be beneficial for viewing and analysis
thereof.
OBJECTS AND SUMMARY OF THE INVENTION
[0009] One of the objects of the present invention is to overcome
certain deficiencies and shortcomings of the prior art systems
(including those described herein above), and provide exemplary
embodiments of methods and arrangement for viewing and analyzing of
one or more biological samples and anatomic structures with
progressively increasing resolutions. Such exemplary methods and
arrangements can be used along with a visual inspection of the data
or by automatic processing procedures of the data to guide the
visualization of areas that are most likely to contain abnormal
and/or unhealthy tissue.
[0010] Accordingly, method, apparatus and arrangement according an
exemplary embodiment of the present invention can be provided and
which may analyze and/or illustrate at least one portion of an
anatomical structure. For example, ain such exemplary embodiment,
light can be forwarded to such portion so as to generate first
information which is related to the portion. For example, the light
can be provided on or within a subject. The first information can
be received, and at least one section of the portion may be
selected based on the first information so as to generate second
information. A magnification of a display of the portion may be
progressively modified as a function of the second information.
[0011] In a further exemplary embodiment of the present invention,
display of position and/or depth of the at least one portion can be
modified (e.g., within the anatomical structure). The second
information can be associated with a region provided within such
portion, and/or may be obtained by user-selecting the region. The
selection can be automatically performed by a processing
arrangement without an input from a user. An area of an abnormality
within the at least one portion can be determined, and the
processing arrangement may perform the selection and modification
so as to display at least one section of the abnormality. An area
of an abnormality can be determined within the portion using the
processing arrangement so as to generate third information, and the
selection can be performed by the user and/or the processing
arrangement as a function of the third information.
[0012] According to yet another exemplary embodiment of the present
invention, the first information can be associated with two-,
three- or four or more-dimensional, representation of the portion.
Further, the portion can have an area that is greater than 1
mm.sup.2 and/or 10 mm.sup.2. A displayed section of the portion can
have an area is less than 1 cm.sup.2, 1 mm.sup.2 and/or 100
.mu..sup.2. The first information can be associated with a confocal
microscopy procedure, a spectrally-encoded confocal microscopy
procedure, an optical coherence tomography procedure, and/or an
optical frequency domain interferometry procedure. An arrangement
can be situated within the anatomical structure so as to provide
the light to the portion.
[0013] Other features and advantages of the present invention will
become apparent upon reading the following detailed description of
embodiments of the invention, when taken in conjunction with the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Further objects, features and advantages of the present
invention will become apparent from the following detailed
description taken in conjunction with the accompanying figures
showing illustrative embodiments of the present invention, in
which:
[0015] FIG. 1 is a schematic illustration of an exemplary
spectrally encoded confocal microscopy (SECM) system;
[0016] FIG. 2A is an exemplary SECM image of a swine intestinal
epithelium, obtained ex vivo, 100 .mu.m from the tissue surface
using a single mode source and single-mode detection (SM-MM)
configuration;
[0017] FIG. 2B is another exemplary SECM image of a swine
intestinal epithelium, obtained using a single-mode source and
multi-mode detection (SM-MM) configuration;
[0018] FIG. 2C is a magnified view of an SECM image of a swine
intestinal epithelium;
[0019] FIG. 3A is an exemplary SECM image of a swine intestinal
epithelium, obtained ex vivo, after compression of the bowel wall
at an imaging depth of 50 .mu.m;
[0020] FIG. 3B is an exemplary SECM image of a swine intestinal
epithelium, obtained ex vivo, after compression of the bowel wall
at an imaging depth of 100 .mu.m;
[0021] FIG. 4 is a schematic illustration of an exemplary SECM
apparatus;
[0022] FIG. 5 is an exemplary SECM image of a USAF chart;
[0023] FIG. 6A is an exemplary SECM image based on data taken from
a lens paper sample, displayed at a magnification of 1.times.;
[0024] FIG. 6B is an exemplary SECM image based on data taken from
a lens paper sample, displayed at a magnification of
4.5.times.;
[0025] FIG. 6C is an exemplary SECM image based on data taken from
a lens paper sample, displayed at a magnification of
16.7.times.;
[0026] FIG. 6D is an exemplary SECM image based on data taken from
a lens paper sample, displayed at a magnification of 50.times.;
[0027] FIG. 6E is an exemplary SECM image based on data taken from
a lens paper sample, displayed at a magnification of
125.times.;
[0028] FIG. 7 is a series of exemplary SECM data obtained from a
lens paper sample at five different focal positions, together with
a combine image that was generated by combining the data in the
five individual images;
[0029] FIG. 8A is an exemplary SECM image based on data taken from
a swine intestinal tissue fragment, displayed at a magnification of
1.times.;
[0030] FIG. 8B is an exemplary SECM image based on data taken from
a swine intestinal tissue fragment, displayed at a magnification of
4.times.;
[0031] FIG. 8C is an exemplary SECM image based on data taken from
a swine intestinal tissue fragment, displayed at a magnification of
20.times.;
[0032] FIG. 8D is an exemplary SECM image based on data taken from
a swine intestinal tissue fragment, displayed at a magnification of
40.times.;
[0033] FIG. 9A are front and elevation side views of microscopic
images of a porcine esophagus in vivo which shows a vascular
network within the submucosa without image enhancement or exogenous
contrast agents using an exemplary embodiment of a method and an
arrangement according to the present invention;
[0034] FIG. 9B is a side view of the microscopic image of a
longitudinal cross-section through a wall of the esophageal at a
location illustrated in FIG. 9A;
[0035] FIG. 9C is a side view of an unwrapped transverse section at
the location illustrated in A;
[0036] FIG. 9D is a side view of an expanded view of a selected
section of the image illustrated in FIG. 9C;
[0037] FIG. 9E is an exemplary image of a representative histology
section obtained from the anatomical region corresponding to the
image illustrated in FIG. 9D;
[0038] FIG. 10 is a flow diagram of an exemplary embodiment of the
method for progressively zooming into a microscopy dataset of an
anatomical structure of the present invention;
[0039] FIG. 11 is a series of exemplary images of esophageal mucosa
obtained using optical coherence tomography ("OCT") techniques,
demonstrating an implementation of an exemplary embodiment of an
automatic processing procedure for identifying normal squamous
mucosa as compared to Barrett's esophagus and adenocarcinoma;
[0040] FIG. 12 is a set of exemplary images of atherosclerotic
plaque obtained using the OCT techniques, which have been processed
to identify a macrophage density; and
[0041] FIG. 13 is a flow diagram of another exemplary embodiment of
the method according to the present invention for progressively
zooming to a microscopy dataset of an anatomical structure based on
the results obtained via a signal processing technique to
automatically identify regions of interest that may be viewed at a
high magnification.
[0042] Throughout the figures, the same reference numerals and
characters, unless otherwise stated, are used to denote like
features, elements, components or portions of the illustrated
embodiments. Moreover, while the subject invention will now be
described in detail with reference to the figures, it is done so in
connection with the illustrative embodiments. It is intended that
changes and modifications can be made to the described embodiments
without departing from the true scope and spirit of the subject
invention as defined by the appended claims.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0043] In accordance with exemplary embodiments of the present
invention, methods and arrangement according to exemplary
embodiments of the present invention can be provided for viewing
and analyzing of one or more biological samples and anatomic
structures with progressively increasing resolutions. Such
exemplary methods and arrangements can be used along with a visual
inspection of the data or by automatic processing procedures of the
data to guide the visualization of areas that are most likely to
contain abnormal and/or unhealthy tissue.
[0044] An exemplary SECM technique is shown in FIG. 1. The output
from a single-mode optical fiber 100, which may be located at a
distal end of a probe, can be collimated by a collimating lens 110,
and then illuminate a dispersive optical element (such as, e.g., a
transmission diffraction grating 120). An objective lens 130 can
then focus each diffracted wavelength to a distinct spatial
location within the specimen, resulting in a transverse line focus
140 where each point on the line may be characterized by a distinct
wavelength. After reflection from the specimen, which may be, e.g.,
biological tissue, the optical signal can be recombined by the
diffraction element 120 and collected by the single-mode fiber 100.
The core aperture of the single-mode fiber 100 can provide a
spatial filtering mechanism that is capable of rejecting
out-of-focus light. Outside the probe (and optionally within a
system console) the spectrum of the returned light can be measured
and converted into confocal reflectance as a function of transverse
displacement within the specimen. The spectral decoding can be
performed rapidly. Thus an image created by scanning the beam in a
direction orthogonal to the line focus can be accomplished by
relatively slow and straightforward mechanical actuation.
[0045] SECM techniques may allow the use of endoscopic RCM, and it
can be capable of providing image data at extremely high rates
using high-speed linear CCD cameras. Commercially available linear
CCD arrays can obtain data at a rate greater than about 60 million
pixels per second. When incorporated into an SECM spectrometer,
these arrays can produce confocal images at speeds that are about
10 times faster than a typical video rate and up to 100 times
faster than some endoscopic RCM techniques. The rapid imaging rate
and fiber-optic design of typical SECM systems can permit
comprehensive, large area microscopy through an endoscopic
probe.
[0046] Techniques using optical coherence tomography ("OCT") and
variations thereof may be used for comprehensive architectural
screening. Acquiring an OCT signal in the wavelength domain, rather
than in the time domain, can provide orders of magnitude
improvement in imaging speed while maintaining excellent image
quality. Using spectral domain OCT ("SD-OCT") techniques,
high-resolution ranging can be conducted in biological tissue by
detecting spectrally resolved interference between a tissue sample
and a reference. Because SD-OCT systems can utilize the same
high-speed linear CCD's as SECM systems, they can also be capable
of capturing images at 60 million pixels/s, which is approximately
two orders of magnitude faster than conventional time-domain OCT
("TD-OCT") systems. With this acquisition rate and resolution,
SD-OCT systems can provide comprehensive volumetric microscopy at
the architectural level in a clinical environment.
[0047] The information provided by SD-OCT and SECM systems can be
complementary, and a hybrid platform utilizing both techniques can
provide information on the architectural and cellular structure of
tissue that may be essential to accurate diagnosis. Although a
combination of disparate technologies typically requires extensive
engineering and may compromises performance, SECM and SD-OCT
systems can share key components, and a high-performance
multi-modality system can be provided without substantially
increasing complexity or cost of the individual systems.
[0048] An SECM system in accordance with certain exemplary
embodiments of the present invention can utilize a wavelength-swept
1300 nm source and a single-element photodetector to obtain
spectrally encoded information as a function of time. With this
system, images can be acquired at rates of up to about 30
frames/second having high lateral (1.4 .mu.m) and axial (6 .mu.m)
resolutions, over a 400 .mu.m field of view ("FOV"). Images of
freshly excised swine duodenum segments were imaged ex vivo with a
high speed system to illustrate the capability of an SECM system to
identify subcellular structures that may be found in specialized
intestinal metaplasia ("SIM"), the metaplastic change of BE.
[0049] FIGS. 2A-2C depict exemplary SECM images of a swine
intestinal epithelium obtained ex vivo using two imaging modes and
corresponding fiber configurations: a single-mode illumination with
single-mode detection ("SM-SM"), and a single-mode illumination
with multi-mode detection ("SM-MM"). The SM-SM image in FIG. 2A
shows the epithelium structure 100 .mu.m from the tissue surface
using a single mode source and single-mode detection. The image of
the same tissue region shown in FIG. 2B, obtained using a using a
single mode source and multi-mode detection (SM-MM) with a
core:aperture ratio of 1:4, appears smoother and may be more easily
interpreted because of the reduction in speckle noise. FIG. 2C is a
magnified view of the image shown in FIG. 2B that shows evidence of
villi containing a poorly reflecting core (e.g., lamina propria or
"lp") and a more highly scattering columnar epithelium. Bright
image densities visible at the base of the columnar cells,
consistent with nuclei (indicated by arrows) are evident in FIG.
2C.
[0050] The thickness of an esophageal wall being imaged in vivo
using OCT techniques can be decreased, e.g., by about a factor of
two using an inflated balloon. The swine intestinal sample shown in
FIGS. 2A-2C was decreased by the same amount, and the subcellular
features observed using SECM techniques were well preserved. FIGS.
3A and 3B show images of this thinned sample obtained at a depth of
50 .mu.m and 100 .mu.m, respectively.
[0051] The penetration depth of a commercial 800 nm laser scanning
confocal microscope was observed to be reduced by about 20% as
compared to that obtained with a 1300 nm SECM system. This reduced
penetration may be a result of increased scattering of the shorter
wavelength source. Thus an SECM system using an 840 nm source may
provide sufficient penetration to identify subcellular structure
of, e.g., an intestinal epithelium.
[0052] An apparatus in accordance with certain exemplary
embodiments of the present invention that is configured to provide
comprehensive SECM images is illustrated schematically in FIG. 4.
This exemplary apparatus can be configured to obtain images from a
cylindrical sample having a length of 2.5 cm and a diameter of 2.0
cm, which are approximately the dimensions of the distal esophagus.
A fiber-coupled 2.0 mW superluminescent diode 200, having a
wavelength centered at 800 nm and a bandwidth of 45 nm (QSSL-790-2,
qPhotonics, Chesapeake, Va.) was configured to illuminate a 50/50
single-mode fiber optic beam splitter 405. Light transmitted
through one port of the splitter was collimated by a collimator 410
and transmitted through a fiber 412 to a focusing apparatus 415 and
to a grating-lens pair that includes a grating 420 (1780 lpmm,
Holographix, LLC, Hudson, Mass.) and a 350230-B asphere lens 425
(Thor Labs, Inc., Newton, N.J.) having a focal length, f, of 4.5
mm, a clear aperture of 5.0 mm, and a NA of 0.55. This arrangement
was capable of producing a 500 .mu.m longitudinal linear array, or
line, of focused, spectrally-encoded spots 430 on an interior
surface of the cylindrical sample. The grating-lens pair was
affixed to the shaft of a motor 435 (1516SR, 15 mm diameter,
MicroMo Electronics, Inc., Clearwater, Fla.) by a housing 440. As
the motor 435 rotated, the spectrally encoded line was scanned
across the inner circumference of the cylindrical sample. The motor
435, housing 440, and grating-lens pair were translated along a
longitudinal axis of the cylindrical sample during rotation of the
motor 435 using a computer-controlled linear stage 445 (Nanomotion
II, 2.5 cm range, Melles Griot, Rochester, N.Y.). This procedure
produced a helical scan of the entire interior surface of the
cylindrical sample.
[0053] Light reflected from the sample was transmitted back through
the optical system into the single-mode fiber 412 and provided by
the fiber 412 to a spectrometer 450 and linear CCD 455 that
includes 2048 pixels and has a 30 kHz line rate (Basler L104K,
Basler Vision Technologies, Exton, Pa.). A computer 460 was used to
store, analyze and display image data provided by the spectrometer
450 and CCD 455. Approximately 60,000 points per motor rotation (at
0.5 Hz, or 30 rpm) were digitized to achieve a 1.0 .mu.m
circumferential sampling density. The longitudinal velocity of the
motor was 0.25 mm/s and the time required for one complete scan of
the cylindrical sample was 100 seconds.
[0054] The 1/e.sup.2 diameter of the collimated beam on the
grating-lens pair was 4.0 mm. As a result, the effective NA of this
exemplary apparatus was approximately 0.4, which corresponds to a
theoretical spot diameter of approximately 1.2 .mu.m and a confocal
parameter of approximately 2.5 .mu.m. In a system that is free of
optical aberrations, the theoretical spectral resolution on the
sample may be 0.8 .ANG., which can yield up to approximately 630
resolvable points across the spectrally encoded line 430. The
spectrometer 450 in the detection arm was designed to exceed the
predicted spectral resolution of the probe.
[0055] An SECM scan of a 1951 USAF resolution chart obtained using
this apparatus is shown in FIG. 5. The smallest bars in this
Figure, which are separated by 2.2 .mu.m, were resolved. A
transverse line spread function full-width-half-maximum ("FWHM")
and an axial FWHM function obtained using a mirror scanned through
the focus were measured as 2.1 .mu.m and 5.5 .mu.m, respectively.
The field of view was observed to be about 500 .mu.m. These
measurements were slightly lower than corresponding theoretical
values, which may be attributed to aberrations in the optical path.
These actual parameters indicate that the exemplary apparatus
described herein is capable of providing sufficient resolution to
be used for confocal microscopy in biological tissue.
[0056] SECM image data for a complete pullback image of a 2.5 cm
phantom specimen are shown in FIG. 6. Polar coordinates were
converted to rectangular coordinates prior to generating these
displayed images. The phantom specimen was made using lens paper
affixed to the inner surface of a 2.1 cm inner diameter Teflon
tube. In a low magnification image shown in FIG. 6A, macroscopic
structure of the paper, including folds and voids, can be observed.
Circumferential stripes that are visible may have resulted from the
lower spectral power and lens aberrations that may be present at or
near the ends of the spectrally-encoded line. Individual fibers and
fiber microstructure can be clearly resolved in regions of this
data set that are presented at higher magnifications, as shown in
FIGS. 6B-6E.
[0057] By adjusting the focusing apparatus 415 in FIG. 4A,
cylindrical two-dimensional ("2D") images of the phantom sample
were acquired at five discrete focal depths over a range of 120
.mu.m. These five images 710-750 shown in FIG. 7 were then summed
to create an integrated image 760, which demonstrates a nearly
complete coverage of the surface of the phantom sample.
[0058] Imaging biological samples using an SECM apparatus such as
that described herein can be complicated by the lack of a centering
apparatus for the optical scan head. In order to provide further
improvements for generating wide-field microscopy images and data,
a sample of swine intestine was placed on top of a 2.0 cm diameter
transparent cylinder. A 360.degree. scan of this sample, which was
acquired in 1 second, is shown in FIG. 8A. Imaged tissue appears in
only one sector of the cylindrical scan because the probe was not
centered and the sample did not wrap completely around the
cylinder. FIGS. 8B-8D show a sequence of magnified regions of this
tissue sample. The image shown in FIG. 8B is an expansion of a 1.5
cm sector outlined by a dotted rectangle in FIG. 8A. Similarly, the
image in FIG. 8C represents an expansion of the rectangle outlined
in FIG. 8B, and the image in FIG. 8D represents an expansion of the
rectangle outlined in FIG. 8C. Magnified images of the tissue in
the image FIG. 8B are suggestive of a glandular structure. The
magnified images in FIGS. 8C-8D exhibit villi and nuclear features
that are similar to those observed using a 1300 nm SECM system, as
shown in FIGS. 2 and 3. Other areas of the SECM scan in FIG. 8A
show artifacts, including specular reflectance from the transparent
cylinder and complete signal dropout, both of which may result from
improper positioning of a focused SECM beam.
[0059] Conducting comprehensive confocal microscopy in patients can
present a variety of technical challenges. Such challenges may
include, e.g., increasing the imaging rate, miniaturizing the probe
optics and mechanical components, incorporating a centering
mechanism, and implementing a technique for dynamically changing
the focal plane.
[0060] The image acquisition speed of an SECM system can be
improved by, e.g., a factor of about 2-4 as compared with the
exemplary system described hereinabove. Such an improvement can be
realized by providing certain modifications. For example, a higher
power semiconductor light source (such as, e.g., a Superlum Diode,
T-840 HP: 25 mW, 840 nm, 100 nm spectral bandwidth) can provide
1000 spectrally resolvable points. The increase in optical power
can improve sensitivity and the larger bandwidth may widen the
field of view, making it possible to scan the SECM beam
approximately two times faster. Also, using an optical circulator
such as, e.g., an OC-3-850 (Optics for Research, Caldwell, N.J.)
can increase the efficiency of light delivered to the probe and
collected from the probe. Using a faster, more sensitive linear CCD
such as, for example, an AVIIVA M4-2048 having 2048 pixels and a 60
kHz readout rate (Atmel Corporation,) can provide a twofold
increase in data acquisition speed and an improved spectral
response over the wavelength range used to generate image data.
Performance may also be improved by using, e.g., a Camera Link
interface that can be capable of transferring data at a rate of
approximately 120 MB/s from a camera to a hard-drive array for
storage.
[0061] Sensitivity, which can be understood to refer to a minimum
detectable reflectance, is a system parameter that can affect
confocal image quality and penetration depth. A fraction of the
incident light, which may be approximately 10.sup.-4 to 10.sup.-7,
can be reflected from skin at depths up to approximately 300 .mu.m
when using a near-infrared RCM technique. Based on the NA of the
objective lens used in the exemplary system in accordance with
certain exemplary embodiments of the present invention described
herein and the observation that skin may attenuate light more
significantly than non-keratinized epithelial mucosa, the exemplary
SECM probe objective described herein may collect approximately
3.times.10.sup.-4 to 3.times.10.sup.-7 of the illuminating light
reflected from deep within tissue. The 25 mW light source may be
separated into, e.g., approximately 1000 independent beams. A
maximum double pass insertion loss can be estimated to be
approximately 10 dB (6 dB from the probe, and 4 dB from the fiber
optics and spectrometer). Each pixel in an array may thus be
illuminated by approximately 50 to 50,000 photons/pixel for each
line integration period based on these estimated parameters.
[0062] Using a multi-mode detection technique, a factor of 10
signal gain may be achieved, resulting in approximately 500 to
500,000 photons/pixel per scan for such a configuration. A single
pixel on an Atmel AVIIVA M4 camera, e.g., can reliably detect light
if a signal is above the dark current fluctuation that occurs at
approximately 240 photons. If this device has approximately a 50%
quantum efficiency at these wavelengths, a minimum detectable
signal can be produced at approximately 480 photons/pixel per scan.
Based on these approximations, an Atmel camera may have sufficient
sensitivity to allow SECM imaging at deeper tissue depths. Quantum
noise-limited detection of a predicted minimum reflectance can be
achieved by using a multi-mode fiber for collection or by
increasing the source power.
[0063] According to one exemplary embodiment of the present
invention, methods and arrangements can be provided for navigating,
analyze and display large microscopic datasets from anatomical
structures.
[0064] FIGS. 9A-9E illustrate various images of a porcine esophagus
in vivo obtained using comprehensive microscopy and the exemplary
embodiments of the methods and arrangements of the present
invention. These exemplary images can be generated by a computer
460 (e.g., personal computer, mini computer, etc.) shown in FIG. 4
or another processing arrangement which may be configured (e.g., by
software) to forward such images to a display 470 of FIG. 4 or
another output arrangement. In addition, the computer 460 can
control various component of the exemplary system of FIG. 4 (e.g.,
motor 435, line translator 445, focusing apparatus 415, etc.) to
focus on various areas of anatomical structures automatically
and/or under a manual control which would enable the navigation,
analysis and display of the large microscopic datasets associated
with the anatomical structures.
[0065] For example, FIG. 9A shows front and elevation side views
900, 905, respectively, of microscopic images of a porcine
esophagus in vivo which provides a vascular network within the
submucosa without image enhancement or exogenous contrast agents
using such exemplary embodiment of the method and arrangement.
Indeed, e.g., 14 GB volumetric data set of FIG. 9A can be rendered
and downsampled for a presentation in arbitrary orientations and
perspectives. The vascular network within the submucosa is shown
without such image enhancement or exogenous contrast agents.
Cross-sectional images can be located on the volume image for
higher resolution viewing using the computer 460 configured for
such exemplary task(s) and other components of the system of FIG.
4.
[0066] FIG. 9B shows a side view 910 of the microscopic image of a
longitudinal cross-section through a wall of the esophageal at a
location illustrated in FIG. 9A. For example, this image 910 is
inverted with epithelium at the top; dimensions: 45 mm horizontal,
2.6 mm vertical. In the raw data, a periodic vertical offset
corresponding to the motion of the beating heart can be observed.
An exemplary embodiment of a surface-aligning procedure can be used
to reduce this artifact but a residual vertical banding, that may
still be observed with a period of 300 microns corresponding to a
heart rate of 90 beats/min. The exemplary longitudinal pitch
between adjacent A-lines is shown as 32 .mu.m.
[0067] FIG. 9C shows a side view 920 of an unwrapped transverse
section (e.g., cylindrical coordinates r & .theta. are mapped
to vertical and horizontal) at the location illustrated in FIG. 9A.
For example, the exemplary dimensions of the illustration are as
follows: 57 mm--horizontal, 2.6 mm--vertical. Both FIGS. 9B and 9C
illustrate the imaging through the entire esophageal wall, and can
enable an identification of the squamous epithelium (e), lamina
propria (lp), muscularis mucosa (mm), submucosa (s), and muscularis
propria (mp). FIG. 9D shows a side view 930 of an expanded view of
a selected section of the image illustrated in FIG. 9C which can be
used to assist with such identification. FIG. 9E shows an exemplary
image of a representative histology section (H&E stain)
obtained from the anatomical region corresponding to the image
illustrated in FIG. 9D.
[0068] For example, FIG. 10 depicts a flow diagram describing an
exemplary embodiment of a method or a procedure according to the
present invention for analyzing and/or viewing the data set at
progressively higher resolutions, which can be executed using the
computer 460 shown in FIG. 4. Particularly, in step 1000, a
microscopic dataset, which can have a resolution of less than 10
.mu.m, may be acquired over a large area of tissue or from a volume
of tissue, or organ therein. The data can then be formatted (in
step 1010) in a representation that may illustrate a low
magnification or low power view of the entire data set or a portion
of the data set. In step 1020, the user may view the data set, and
using a computer interface, can select (a) a rectangular region,
(b) a point, (c) an arbitrary shaped region, and/or (d) a depth in
which to visualize a higher magnification view. The new region can
be viewed in step 1020, and the user can (a) select another region,
(b) zoom in at a point, (c) zoom out, (d) translate the current
view in three dimensions, and/or (e) change the depth location of
viewing within the dataset.
[0069] The entire exemplary process illustrated in FIG. 10 can be
repeated until the area or areas of interest can be identified for
visualization. The user can select different images at any
magnification or view to store for later inspection. Labeling of
each individual view can also be conducted during the exemplary
navigation procedure. Various regions/images at different
magnifications/locations can be bookmarked so that the user can
return to the same region/image during a subsequent navigation
session.
[0070] FIGS. 6A-6E, 7 and 9A-9E illustrate examples of the
progressive magnification while viewing a large area microscopic
dataset.
[0071] The exemplary embodiment of the navigation procedure
described herein can be implemented by the computer 460, and also
utilize various processing techniques to assist the user in
determining various areas to magnify and view the sample, and
different portions and regions thereof. For example, FIG. 11
depicts a series of exemplary images of esophageal mucosa obtained
using optical coherence tomography ("OCT") techniques,
demonstrating an implementation of an exemplary embodiment of an
automatic processing procedure for identifying normal or benign
squamous mucosa as compared to Barrett's esophagus and
adenocarcinoma via an analysis of OCT image spatial
frequencies.
[0072] As shown in FIG. 11, OCT images 1100, 1110, and 1120 and
spatial frequency distributions 1105, 1115, and 1125 of different
disease states are shown. Squamous epithelium 1100 (SE) has
vertical spatial frequencies (see arrows 1007 in panel 1105),
corresponding to horizontal layers that may not be present in SIM.
A widely varying spatial frequency distribution are shown in the
exemplary OCT images of adenocarcinoma (CA) 1120 and its
corresponding spatial frequencies 1125 compared with SIMND 1110 and
1115. FIG. 12 depicts an illustration of a macrophage content 1210
obtained from OCT images of atherosclerotic plaques 1200 by
determining the normalized standard deviation parameter (NSD). The
density of macrophages can be obtained and displayed as an image
using a color table 1220.
[0073] These and other exemplary image processing analysis
procedures and steps can be applied to the microscopic data set and
utilized to highlight regions of potential disease for subsequent
directed navigation. FIG. 13 depicts a flow diagram of an exemplary
embodiment of the method and procedure according to the present
invention for navigating and evaluating the microscopic image data
set. In this exemplary method/procedure, a microscopic dataset can
be obtained in step 1300, which preferably has a resolution of less
than 10 .mu.m, possibly acquired over a large area of tissue or
from a volume of tissue or organ therein. The data is then
processed automatically by a processing arrangement (e.g., using
the computer 460) in step 1310 to identify regions/locations that
either contain areas suspect for disease or conversely areas that
are suspected to contain no disease (i.e., healthy portions). In
step 1320, the unhealthy areas can be represented using a color or
other marking method, and then viewed at low magnification of the
entire microscopic data volume in step 1330.
[0074] The user can then select a region to view in step 1340,
guided by the processing data and the representation thereof. The
user may then view the data set and, using a computer interface,
select (a) a rectangular region, (a) a point, (c) an arbitrary
shaped region, and/or (d) a depth in which to visualize a higher
magnification view. The new region can be viewed, and the user (or
the computer 460) can manually or automatically (a) select another
region, (b) zoom in at a point/zoom out (step 1350), (d) translate
the current view in three dimensions, and/or (e) change the depth
location of viewing within the dataset. Further, in step 1360, the
user can view the newly illustrated region. The exemplary
method/procedure may be repeated until the area(s) of interest
is/are identified for visualization. The user or the computer 460
can select different images at any magnification or view to store
for later inspection. Labeling of each individual view can also be
conducted during the exemplary navigation process. The
regions/images at different magnifications/locations can be
bookmarked and stored so that the user can return to the same
region/image during a subsequent navigation session.
[0075] The foregoing merely illustrates the principles of the
invention. Various modifications and alterations to the described
embodiments will be apparent to those skilled in the art in view of
the teachings herein. Indeed, the arrangements, systems and methods
according to the exemplary embodiments of the present invention can
be used with any OCT system, OFDI system, SD-OCT system or other
imaging systems, and for example with those described in
International Patent Application PCT/US2004/029148, filed Sep. 8,
2004, U.S. patent application Ser. No. 11/266,779, filed Nov. 2,
2005, and U.S. patent application Ser. No. 10/501,276, filed Jul.
9, 2004, the disclosures of which are incorporated by reference
herein in their entireties. It will thus be appreciated that those
skilled in the art will be able to devise numerous systems,
arrangements and methods which, although not explicitly shown or
described herein, embody the principles of the invention and are
thus within the spirit and scope of the present invention. In
addition, to the extent that the prior art knowledge has not been
explicitly incorporated by reference herein above, it is explicitly
being incorporated herein in its entirety. All publications
referenced herein above are incorporated herein by reference in
their entireties.
* * * * *