Optical coherence tomography (OCT) is a non-invasive imaging technique that uses light to capture high-resolution cross-sectional images of the retina. OCT was introduced in 1991 and has since become a widely used tool for ophthalmic diagnosis. It provides 10 micrometer resolution images, allowing visualization of individual retinal layers. Several technological advancements, including Fourier-domain OCT and swept-source OCT, have improved imaging speeds and depths. OCT angiography allows visualization of the retinal and choroidal vasculature without dyes. Precise quantitative and qualitative analysis of OCT images provides crucial information for diagnosing and monitoring many retinal conditions.
OCT is a great technology,Many ophthalmologist find very difficult to understand it ,SO I have tired to simplify it as much as possible .Hope everyone can understand now onwards the basic about OCT .
Every feedback s most welcomed sothat i can improve further in coming days
Please email your feedback to me in the following address
yourgyanu@gmail.com
OCT is a great technology,Many ophthalmologist find very difficult to understand it ,SO I have tired to simplify it as much as possible .Hope everyone can understand now onwards the basic about OCT .
Every feedback s most welcomed sothat i can improve further in coming days
Please email your feedback to me in the following address
yourgyanu@gmail.com
Optical coherence tomography angiography optovue a very basic lecture detailing the new advancement of dyeless angiography by spectral domain OCT system and SSADA and Motion correction algorithm
Optical coherence tomography angiography optovue a very basic lecture detailing the new advancement of dyeless angiography by spectral domain OCT system and SSADA and Motion correction algorithm
This presentation is mainly focused on the clinical diagnosis and interpretation of oct macula.This is presented on 4th year optometry as topic presentation.
optical coherence tomography is a new tool that makes retinal diagnosis easier. the above ppt includes a detailed and precise notes on OCT and its interpretation.
Review of the imaging modalities in Glaucoma. Structural loss precedes functional loss. Presentation includes a review of OCT, HRT and GDxVcc for posterior segment as well as AS-OCT and UBM for anterior segment.
OPTICAL COHERENCE TOMOGRAPHY (SKIN OCT)....
Optical coherence tomography (OCT) is an established medical imaging technique that uses light to capture micrometer-resolution, three dimensional images from within optical scattering media (e.g., biological tissue). Optical coherence media (e.g., biological tissue). Optical coherence tomography is based on low coherence interferometry, typically employing near-infrared light. The use of relative long wavelength light allows it to penetrate into the scattering medium. Confocal microscopy, another optical technique, typically penetrates less deeply into the sample but with higher resolution.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
2. Overview
• History and evolution.
• What is OCT ?
• OCT Physics
• What is OCT Angiography
• Interpretation of OCT.
• Limitations.
3. History
• OCT was first introduced in 1991 and has found many uses outside of
ophthalmology, where it has been used to image certain non-transparent
tissues.
• Due to the transparency of the eye (i.e. the retina can be viewed through the
pupil), OCT has gained wide popularity as an ophthalmic diagnostic tool.
Optical coherence tomogram of a
fingertip. It is possible to observe
the sweat glands, having
"corkscrew appearance"
5. What is OCT ?
• Optical Coherence Tomography (OCT) is a non-invasive,
noncontact, technique for obtaining sub-surface images of
translucent or opaque materials at a resolution equivalent to a low-
power microscope.
• Reflected light is used instead of sound waves(It is an ‘optical
ultrasound’, imaging reflections from within tissue to provide
cross-sectional images)
• it provides tissue morphology imagery at much higher resolution
(better than 10 µm) than other imaging modalities such as MRI or
ultrasound.
6. Comparison of various imaging methods according to their resolutions and penetration depths.
The length of the “pendulum” represents the penetration depth while the diameter of the circle
represents the spatial resolution of the imaging
7. • Piezoelectric effect( curie brothers 1880)
• Came in to ophthalmology in 1956
• Resolution 50 micro m
• High frequency 35-50 MHz
• Can combine with Doppler / movement and flow within a tissue / colour
coded for high and low flow
• Penetrates hazy media
B -SCAN
8. • Contact
• Poor resolution
• Can image when media hazy
• Less costly
B-SCAN VS OCT
9. The key benefits of OCT over B scan:
Advantages
• Non-contact
• Minimal cooperation needed
• Resolution ~ 10 μm
• Pick up earliest signs
of disease
• Quantitatively monitor
disease/staging
Disadvantages
• Best for optically transparent tissues
• Diminished penetration through
Retinal/subretinal hemorrhage
• Requires pupil diameter > 4 mm
10. • Fiber-based OCT system in a Michelson configuration. The light (Infrared light
840nm)from a low-coherence source is split in two by the coupler with each part
traveling along a separate arm of the interferometer,
• the reference and the sample arm. The light backscattered from the reference
mirror and from the sample recombine at the coupler and generate an interference
pattern, which is recorded by a single point detector
OCT Basic principle
11. • Interferometry is used to record the optical path length of received
photons allowing rejection of most photons that scatter multiple times
before detection.
• Thus OCT can build up clear 3D images of thick samples by rejecting
background signal while collecting light directly reflected from
surfaces of interest.
12. Axial resolution, or
definition,
determines which
retinal layers can be
distinguished. Axial
resolution is determined
by the
light source.
Transverse resolution is determined by optics of the eye, as limited by
pupil size, and as corrected by the scanner
13. OCT Platforms
• Time domain (TD-OCT)
• Fourier-domain OCT (FD-OCT).
Fourier-domain OCT imaging can also be done in two ways:
spectral-domain OCT (SD-OCT)
swept-source OCT (SS-OCT).
• High definition- HD
• Array of detectors/ 100000 scans per second ( 200 times faster than
time domain)
14. 1. Time Domain OCT
• In TD-OCT a mirror in the reference
arm of the inter-ferometer is moved
to match the delay in various layers of
the sample
• The resulting interference is
processed to produce the axial scan
waveform.
• The reference mirror must move one
cycle for each axial scan. The need
for mechanical movement limits the
speed of image acquisition.
15. Fourier-domain OCT (FD-OCT)
• In FD-OCT the reference mirror is kept
stationary. The spectral pattern of the
interference between the sample and the
reference reflections is measured • The spectral
interferogram is fourier transformed to provide
an axial scan.
• The absence of moving part allows the image to be
acquired very rapidly .
• the full spectral bandwidth sets the axial
resolution.
• Reflections from all layers in the sample are
detected simultaneously.
• This parallel axial scan is much more efficient,
resulting in both greater speed and higher signal-
to-noise ratio.
16. TD-OCT vs FD-OCT
• Spectral domain measures retinal thickness from RPE to ILM
• Time domain measures retinal thickness from IS/OS to ILM
17. Swept-source OCT (SS-OCT)
• SS-OCT has improved acquisition
speed, volume and depth of ocular
tissue measurements compared with
SD-OCT technology.
• has a scan speed of 100,000 A-scans
per second and uses a 1050nm
wavelength to pass through
cataracts and retinal hemorrhages.
• It is the first ophthalmic diagnostic
technology to demonstrate the entire
structure of the posterior
precortical vitreous pocket
(PPVP) in vivo.
.
18. Swept-source OCT (SS-OCT)
• The roles of the PPVP in
physiological posterior vitreous
detachment and Vitreoretinal
interface disorders have now been
elucidated
• Deeper penetration of SS-OCT has
made it possible to view the choroid.
• It also has an important role in
central serous chorioretinopathy
and uveitis.
• Treat Harada disease by monitoring
the choroidal thickness.
19. OCT Angiography
• Optical coherence tomography
angiography (OCT-A) emerged as a
non-invasive technique for imaging
the microvasculature of the retina
and choroid, and the first clinical
studies using this innovative
technology were published in 2014.
OCT-A technology uses laser light reflectance of the
surface of moving red blood cells to accurately
depict vessels through different segmented areas of
the eye, thus eliminating the need for intravascular
dyes
20. OCT interpretation
2 MODES OF INTERPRETATION - Objective & Subjective
For accurate interpretation both have to be combined
OCT reading must be done in 2 stages :
1.Qualitative and quantitative analysis
2.Deduction and synthesis
21. Qualitative Analysis
• Morphological studies -
- Overall retinal structural changes, changes in retinal outline , retinal
structural changes and morphological changes in the post layers
-Anomalous structures- pre/epi/intra/sub retinal
• Reflectivity study - hyper/hypo/ shadow areas
Quantitative Analysis
• Thickness, Volumetery and shadow areas
22. Color coding in OCT
Those with low reflectivity are represented by dark colors (black and blue).
photoreceptor layer,choroid,vitreous fluid or blood
Intermediate reflectivity is shown Green.
Highly reflective structures are shown in bright colures (white and red)
Nerve Fiber Layer, RPE,choriocapillaris
23. Interpretation of retinal scan
• Vitreous anterior to retina is non reflective and is seen as a dark space.
• Vitreo retinal interface is well defined due to contrast between the non
reflective vitreous and backscattering retina
24. 1. Anterior boundary of retina formed by highly reflective RNFL is seen as a red layer due to
bright back scattering.
2. Posterior boundary of retina is also seen as a red layer representing highly reflective (RPE) and
chorio capillaries
3.Outer segment of retinal photoreceptors, being minimally reflective are represented by dark layer
just anterior to RPE
4.Different intermediate layers of neurosensory retina seen as an alternating layer of moderate and
low reflectivity.
Retinal layers are represented as below
32. Advanced Vaisualization
The Tissue Layer image allows you to isolate
and visualize a layer of the retina. The thickness
and placement of the layer are adjustable. This
provides an optical biopsy of the retina by
extracting the layer of interest
33. Each high definition line is comprised of 4096 A-scans
Rotation, length of lines and height of scan area can be adjusted
Custom 5-Line Raster Scan
34. Limitations
• OCT utilizes light waves (unlike ultrasound which uses
sound waves) media opacities can interfere with optimal
imaging.
eg; vitreous hemorrhage, dense cataract or corneal
opacities.
• Patient movement can diminish the quality of the image.
• The quality of the image is also dependent on the
operator.