This document discusses neurosonology and transcranial Doppler ultrasound (TCD). It defines neurosonology as ultrasonic imaging of the brain and neural structures. TCD provides noninvasive, real-time measures of blood flow in the brain's basal arteries. The document outlines the clinical applications of TCD, including monitoring cerebral vasospasm after subarachnoid hemorrhage, detecting intracranial stenosis, assessing acute ischemic stroke, and screening for stroke risk in children with sickle cell disease. TCD is a useful tool for diagnosing and monitoring various cerebrovascular disorders.
Acute stroke management
IV thrombolysis guidelines
IV thrombolysis side effects
Early CT changes in stroke
ASPECTS scoring
AHA stroke guidelines
Thrombolysis controversies
Summary and illustrations of various traumatic brain injury including primary and secondary lesions as well as limited information on indications of brain imaging in trauma
Acute stroke management
IV thrombolysis guidelines
IV thrombolysis side effects
Early CT changes in stroke
ASPECTS scoring
AHA stroke guidelines
Thrombolysis controversies
Summary and illustrations of various traumatic brain injury including primary and secondary lesions as well as limited information on indications of brain imaging in trauma
SUMMARY:
- Neurophysiologic monitoring not universally adopted but in many centers has become routine monitor for some surgical procedures
- Ideal neurophysiologic monitoring in the neurosurgical procedure should be: non-invasive (v.s invasive), high sensitivity & specificity, cost effective, easy to use, simple instrumentation, and real time or continous monitoring.
This lecture prides 8 easy steps of scanning the neonatal brain through anterior fontanelle ,followed by examples of most commonly encountered abnormalities.
I've relaunched my website http://intraoperativeneuromonitoring.com. To kick things off, I am doing "30 Days Of Neuromonitoring" where I post an IONM article every business day for 30 days starting Oct 3rd. I've also released my CNIM Crash Course Oct 1st. A DABNM Crash Course should be done by December.
This presentation includes stroke and infarct latest defination an pathophysiology and CT MRI imaging features and management . This presntation help alot. Thanks
this presentation targets radio-diagnosis, neurology and neurosurgery junior staff, it presents simple basics of CT perfusion including principle, technique, applications, interpretation with few quiz cases.
CONCEPT OF NODOPATHIES AND PARANODOPATHIES.pptxNeurologyKota
emergence of autoimmune neuropathies and role of nodal and paranodal regions in their pathophysiology.
Peripheral neuropathies are traditionally categorized into demyelinating or axonal.
dysfunction at nodal/paranodal region key for better understanding of patients with immune mediated neuropathies.
antibodies targeting node and paranode of myelinated nerves have been increasingly detected in patients with immune mediated neuropathies.
have clinical phenotype similar common inflammatory neuropathies like Guillain Barre syndrome and chronic inflammatory demyelinating polyradiculoneuropathy
they respond poorly to conventional first line immunotherapies like IVIG
This presentation briefs out the approach of dementia assessment in line with consideration of recent advances. Now the pattern of assessment has evolved towards examining each individual domain rather than lobar assessment.
This presentation contains information about Dementia in Young onset. Also it describes the etiologies, clinical feature of common YOD & their management.
Entrapment Syndromes of Lower Limb.pptxNeurologyKota
This presentation contains information about the various Entrapment syndromes of Lower limb in descending order of topography. It also contains information about etiology, clinical features and management of each of these entrapment syndromes with special emphasis on electrodiagnostic confirmation.
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.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
263778731218 Abortion Clinic /Pills In Harare ,sisternakatoto
263778731218 Abortion Clinic /Pills In Harare ,ABORTION WOMEN’S CLINIC +27730423979 IN women clinic we believe that every woman should be able to make choices in her pregnancy. Our job is to provide compassionate care, safety,affordable and confidential services. That’s why we have won the trust from all generations of women all over the world. we use non surgical method(Abortion pills) to terminate…Dr.LISA +27730423979women Clinic is committed to providing the highest quality of obstetrical and gynecological care to women of all ages. Our dedicated staff aim to treat each patient and her health concerns with compassion and respect.Our dedicated group ABORTION WOMEN’S CLINIC +27730423979 IN women clinic we believe that every woman should be able to make choices in her pregnancy. Our job is to provide compassionate care, safety,affordable and confidential services. That’s why we have won the trust from all generations of women all over the world. we use non surgical method(Abortion pills) to terminate…Dr.LISA +27730423979women Clinic is committed to providing the highest quality of obstetrical and gynecological care to women of all ages. Our dedicated staff aim to treat each patient and her health concerns with compassion and respect.Our dedicated group of receptionists, nurses, and physicians have worked together as a teamof receptionists, nurses, and physicians have worked together as a team wwww.lisywomensclinic.co.za/
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
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
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.
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
2. • Definition : Ultrasonic imaging of the brain and other neural
structures.
• Includes :
– Transcranial Doppler ultrasound
– Ultrasound of Nerves
– Carotid Ultrasound
4. • TCD provides rapid, relatively inexpensive, noninvasive,
real-time measures of blood flow characteristics and
cerebrovascular hemodynamics within the basal arteries of
the brain.
• Can be used to measure flow velocity in the basal arteries of
the brain to assess relative changes in flow, diagnose focal
vascular stenosis, or to detect embolic signals within these
arteries.
5. • Can also be used to assess the physiologic health of a
particular vascular territory by :
– measuring blood flow responses to changes in blood
pressure (cerebral autoregulation)
– changes in end-tidal CO2 (cerebral vasoreactivity) or
– cognitive and motor activation (neurovascular coupling or
functional hyperemia).
• TCD is the most convenient way to monitor vascular changes
in response to interventions during acute cerebrovascular
events at the bedside.
6. • Established utility in the clinical diagnosis of a number of
cerebrovascular disorders such as acute ischemic stroke,
vasospasm, SAH, sickle cell disease, as well as other
conditions such as brain death.
• Physiologic data obtained from these measurements are
complementary to structural data obtained from various
modes of currently available vascular imaging.
• Clinical indication and research applications for this mode of
imaging continue to expand.
7. BASIC PRINCIPLES
• Principle - Doppler effect.
• Ultrasound waves emitted from the Doppler probe are
transmitted through the skull and reflected by moving RBCs
within the intracerebral vessels.
• The difference in the frequency between the emitted and
reflected waves (Doppler shift frequency) is directly
proportional to the speed of the moving RBCs (blood flow
velocity).
• Because blood flow within the vessel is laminar, the Doppler
signal obtained actually represents a mixture of different
Doppler frequency shifts forming a spectral display of the
distribution of the velocities of individual RBCs on the TCD
monitor.
8. • Spectral analysis can then be used to obtain measures of
blood flow velocity, as well as a few other characteristics of
flow within the insonated blood vessel.
• The specific parameters obtained from this spectral analysis
include Peak systolic velocity (Vs), End diastolic velocity (Vd),
Systolic upstroke or acceleration time, Pulsatility index (PI),
and time-averaged mean maximum velocity (Vmean ).
• The V mean is a continuous trace of peak velocities as a
function of time and in most TCD instruments, it is calculated
and displayed automatically.
9.
10. • The propagation speed of a wave - a constant that can be
obtained for various mediums (speed in soft tissue is 1541 m/s).
•Theta (θ) = the angle of insonation.
•If angle = 0, i.e. the emitted wave is parallel to the direction of
flow - the most accurate measure of flow velocity.
•The larger the angle, the greater is the error in velocity measure.
•Therefore, it is important to minimize this angle to < 30 degrees
to keep the error below 15%.
11. Physiologic Determinants of Blood Flow
Velocity and Indices
• A number of physiologic variables can impact blood flow
velocity as measured by TCD.
• For eg. Age, gender, hematocrit, viscosity, carbon dioxide,
temperature, blood pressure, and mental or motor activity.
• Therefore, it is important to remember that during the course
of a TCD study, any measured differences in blood flow
velocity should be interpreted in the context of these
variables.
• All studies should be conducted with the patients at rest—not
speaking or moving their limbs.
12. • Blood flow velocities in the basal arteries of the brain decline
@ 0.3 to 0.5% per year between 20 to 70 years of age.
• Women have been shown to have higher flow velocities than
men between 20 to 60 years of age - difference may be
explained by the lower hematocrit in premenopausal women.
• no detectable gender difference - >70 years.
• Hematocrit and viscosity are inversely related to cerebral
blood flow velocity.
• Best exemplified in children with Sickle cell anemia who have
a significant drop in their mean flow velocities after a blood
transfusion.
• Blood flow velocities increase by 20% with a drop in
hematocrit from 40% to 30%.
13. • Partial pressure of CO2 - major influence on cerebral blood
flow velocity.
• Measured blood flow velocity can also be higher with higher
systemic BP despite an intact autoregulatory system.
• Particularly important in patients with SAH who are
monitored for cerebral vasospasm as manifested by elevated
cerebral blood flow velocity and who may simultaneously be
undergoing induced hypertension to treat vasospasm.
• The effect of temperature on cerebral blood flow velocities -
not well established.
14. TYPES OF TRANSCRANIAL DOPPLER DEVICES
• Two types of TCD equipment are currently available:
Nonduplex (nonimaging) and Duplex (imaging) devices.
• In Nonduplex devices, the arteries are identified “blindly”
based on the audible Doppler shift and the spectral display.
• Specific vessel identification is based on standard criteria,
which includes the cranial window used, orientation of the
probe, depth of sample volume, direction of blood flow,
relationship to the terminal internal carotid artery, and
response to various maneuvers such as the common carotid
artery compression.
15. • The imaging B-mode transcranial color-coded duplex (TCCD)
combines pulsed wave Doppler ultrasound with a cross-
sectional view of the area of insonation, which allows
identification of the arteries in relation to various anatomic
locations.
• The color-coded Doppler also depicts the direction of the flow
in relation to the probe (transducer) while recording blood
flow velocities.
• However, in TCCD, the angle of insonation can be measured
and used to correct the flow velocity measurement.
16. THE TRANSCRANIAL DOPPLER EXAMINATION
• Performed using a 2 MHz frequency ultrasound probe.
• The higher frequency probes used in extracranial Doppler
studies not applicable for intracranial measurements because
higher frequency waves are not able to adequately penetrate
through the skull.
• Insonation of the cerebral arteries only possible through
thinner regions of the skull, termed Acoustic windows.
• Therefore, familiarity with the anatomic location of cerebral
arteries relative to the acoustic windows and blood flow
velocities for the various arteries is critical for accurate blood
flow measurements through the nonduplex mode.
17. • In general, four main acoustic windows have been described:
– The Transtemporal window
– the Transorbital window
– the Suboccipital window
– the Submandibular window and
• Although each window has unique advantages for different
arteries and indications, a complete TCD examination should
include measurements from all four windows and the course
of blood flow at various depths within each major branch of
the circle of Willis should be assessed.
22. CLINICAL APPLICATIONS OF TCD
1. SUBARACHNOID HEMORRHAGE & CEREBRAL VASOSPASM
• Angiographic cerebral vasospasm (VSP) occurs in 2/3 patients
with aneurysmal SAH with half becoming symptomatic.
• Significant direct correlation between VSP severity after SAH
and flow velocities in most cerebral arteries.
• TCD is much more sensitive for detecting proximal versus
distal VSP.
• Proximal VSP in any intracranial artery results in segmental or
diffuse elevations of the mean flow velocities without a
parallel flow velocity increase in the feeding extracranial
arteries such as the carotid or the vertebral arteries.
23. • The Lindegaard ratio (LR), defined as the ratio between the
time mean average (Vmean) velocity of the MCA to ICA helps
differentiate hyperemia from VSP.
• Hyperemia would result in flow elevations in both the MCA
and ICA and result in an LR < 3, whereas VSP would
preferentially elevate the MCA flow over the ICA with LR > 6.
• LR between 3 and 6 is a sign of mild VSP and > 6 is an
indication of severe VSP.
• Since distal VSP cannot be insonated - , increased Pulsatility
Index, indicating increased resistance distal to the site of
insonation, is used as a surrogate measure of distal VSP.
24. • In general, TCD flow velocity criteria - most reliable for
detecting angiographic MCA and basilar artery VSP.
• Some of the findings in MCA VSP include:
– MCA Vmean > 180 cm/s
– a sudden rise in MCA Vmean by > 65 cm/s or 20% increase
within a day during posthemorrhage days 3 to 7
– LR > 6 and
– abrupt increase in PI > 1.5 in two or more arteries
suggesting increase in ICP and/or VSP.
• TCD is most useful in monitoring the temporal course of
angiographic VSP following SAH.
• Sporadic measurements, especially if started after the
development of vasospasm, are less useful.
25. 2. INTRACRANIAL STENO-OCCLUSIVE DISEASE
• Intracranial atherosclerosis is a significant risk factor for
ischemic strokes and transient ischemic attacks (TIAs),
accounting for 10% of such events.
• TCD can be used to detect stenosis and occlusion of the
carotid siphon, proximal MCA, ACA, PCA, and basilar as well as
intracranial vertebral arteries.
• Due to the greater tortuosity and anatomic variability of the
vessels in the posterior circulation, the sensitivity, specificity,
positive predictive value, and negative predictive value of TCD
is generally higher in the anterior circulation.
26. • Diagnosis of stenosis > 50% using TCD is based on the
following criteria:
(1) acceleration of flow velocity through the stenotic segment
(2) decrease in velocity distal to the stenotic segment
(poststenotic dilatation)
(3) side-to-side differences in mean flow velocity and
(4) disturbances in flow (i.e., turbulence and murmurs).
• Intracranial occlusion diagnosed by absence of flow at the
normal position and depth for a specific vessel (despite
adequate “acoustic window” and visualised other vessels in
the vicinity)
• In addition, one may also find that flow velocities are
increased in other intracranial vessels due to activation of
collateral vessels.
27. 3. ACUTE ISCHEMIC STROKE
• TCD particularly useful in acute ischemic stroke where
repeated TCD studies can be used to track the course of an
arterial occlusion before and after thrombolysis.
• TCD can detect acute MCA occlusions with high (> 90%)
sensitivity,specificity, and positive and negative predictive
values.
• Can also detect occlusion in the ICA siphon, vertebral, and
basilar arteries with reasonable (70 to 90%) sensitivity and
positive predictive value and excellent specificity and negative
predictive value (> 90%).
28. • Recent studies suggest that ultrasound may also have an
independent effect in augmenting thrombolysis of the
occluded vessel in patients presenting with acute thrombosis.
(Eggers J et al : Effect of ultrasound on thrombolysis of
middle cerebral artery occlusion. Ann Neurol
2003;53(6):797–800)
• Continuous TCD recording significantly increased tPA-induced
arterial recanalization in the Clotbust trial.
• In this trial, 83% of patients achieved either partial or
complete recanalization with tPA and TCD monitoring
compared with 50% recanalization with tPA treatment alone.
29. • Early TCD findings can be very useful for prognosis in patients
presenting with acute ischemic stroke.
• Intracranial arterial occlusion detected by TCD is associated
with poor 90-day outcome, whereas a normal TCD study is
predictive of early recovery.
• Delayed (> 6 h) spontaneous recanalization as demonstrated
by TCD, is also independently associated with greater risk of
hemorrhagic transformation.
• In a recent study of 489 patients with recent TIA or minor
stroke, mean flow velocity and the ratio of pulsatility to mean
flow velocity were independent risk factors for not only stroke
recurrence, but also the occurrence of other major vascular
events (stroke, myocardial infarction, and vascular death)
30. 4. COLLATERAL FLOW
• Knowledge of collateral flow patterns of the basal arteries of
the brain has significant clinical implications in the
management of patients with cerebrovascular
atherothrombotic disease.
• Degree of collateral flow is correlated with infarct volume and
clinical outcome in patients with ischemic stroke.
• TCD can provide real-time information regarding the direction
and the velocity of blood flow in known intracranial collateral
channels, which become active in acute and/or chronic steno-
occlusive cerebrovascular diseases.
31. 5. SICKLE CELL DISEASE
• Children with sickle cell disease (SCD) have chronic hemolysis
resulting in low hemoglobin levels.
• Chronic anemia and hypoxia trigger angiogenesis and
neovascularization.
• In addition, the interaction of the sickled red cells with the
endothelium causes inflammation and intracranial stenosis.
32. • The compromised vascular system predisposes these children
to both ischemic and hemorrhagic infarcts.
• An increase Vmean > 200 cm/s in the ICA or MCA detected by
TCD has been shown to be associated with increased risk of
ischemic stroke in these children.
• In the Stroke Prevention Trial in Sickle Cell Disease (STOP),
children between 2 to 16 years old with no history of stroke
and MCA velocity threshold of 200 cm/s were randomly
allocated to standard care or to periodic blood transfusion
therapy to lower the hemoglobin S concentration to < 30% of
total hemoglobin.
• Blood transfusion based on mean flow velocity resulted in
92% stroke risk reduction.
33. • Following the TCD criteria in the STOP trial, a fivefold decrease
in the rate of first stroke was observed in children with SCD.
• In a retrospective cohort of 475 children, the incidence of
stroke declined 10-fold following TCD screening and
prophylactic blood transfusion over an 8-year period.
34. • The STOP II trial assessed the safety of discontinuing long-
term blood transfusion in children who had normal MCA flow
velocities and who had received transfusions for 30 months or
longer.
• The study was stopped early due to increased MCA flow
velocities and new ischemic strokes in the group that
discontinued transfusion.
• There were no strokes in the group that continued periodic
transfusion.
35. • Because early TCD screening coupled with prophylactic
transfusion seems to reduce overt stroke in children with SCD,
TCD assessment should now be a routine component of
preventive care for these children.
• TCD screening should be avoided during acute illnesses
because factors such as hypoxia, fever, hypoglycemia, and
worsening anemia may impact flow velocity measures.
• The impact of TCD based transfusion on subsequent stroke
risk has not been studied in adults with SCD.
36. 6. MICRO-EMBOLI DETECTION
• TCD is the only medical device that can detect circulating
cerebral microemboli, both solid and gaseous, in real-time.
• Based on backscatter of the ultrasound waves from the
emboli resulting in high-intensity transient signals (HITS) or
embolic signals in the Doppler spectrum as they travel
through the insonated vessel.
• The backscatter of the ultrasound from gaseous emboli are
higher than that of solid emboli of a similar size, which in turn
is higher than the backscatter observed from red blood cells
within normal flow.
• Embolic signals using TCD ultrasound - detected in patients
with carotid stenosis, myocardial infarction, atrial fibrillation,
and mechanical cardiac valves.
37.
38. • The role of TCD in antithrombotic therapy was subsequently
investigated in the CARESS (Clopidogrel and Aspirin for
Reduction of Emboli in Symptomatic Carotid Stenosis) trial,
which tested the effect of antithrombotic medications on
patients with symptomatic carotid stenosis > 50%.
• Patients with embolic signals were randomized to
combination antithrombotic therapy with clopidogrel and
aspirin or to aspirin therapy alone.
• TCD recording in the ipsilateral MCA on day 7 of the treatment
showed that the combination therapy was more effective
than aspirin alone in reducing embolic signals.
39. 7. CEREBRAL CIRCULATORY ARREST
• A decrease in cerebral perfusion pressure associated with
increases in ICP and PI result in compression of the
intracranial arteries and cessation of flow to the brain, leading
to cerebral circulatory arrest (CCA).
• The pattern of cerebral blood flow leading to CCA and brain
death can be visualized by TCD and monitored continuously at
bedside.
• When the ICP increases to match the diastolic perfusion
pressure, diastolic cerebral blood flow approaches zero.
40.
41. • With continued rise in ICP, diastolic blood flow reappears, but
it is in the opposite direction (reversed flow), visualized as
retrograde flow in the TCD.
• Systolic waveforms also become spiked.
• The retrograde or oscillatory diastolic flow along with systolic
spikes, result in no net forward cerebral blood flow and are
characteristic of CCA.
• TCD has very high sensitivity (96.5%) and specificity (100%) in
the diagnosis of cerebral circulatory arrest, but the possibility
of temporary arrest should be excluded by having the systolic
blood pressure > 70 mm Hg during the TCD assessment.
43. • In 1988, Fornage produced the first review of imaging findings
of peripheral nerves using sonography.
• USG remains an underutilized modality
• An excellent cost-effective modality in imaging of peripheral
nerves.
• The newer high-frequency probes allow high-resolution
imaging at relatively superficial location.
• USG can detect and evaluate traumatic, inflammatory,
infective, neoplastic, and compressive pathologies of the
peripheral nerves.
44. TECHNIQUE
• Almost all the nerves including digital nerves can be imaged
by USG.
• Before starting the scan of a peripheral nerve in a particular
region, one needs to know the detailed anatomy.
• A high-frequency linear array probe (8-15 MHz) is used.
• The examination is started from a known anatomic landmark
near the nerve.
• Once the nerve is localized in the short axis, it is traced
cranially and caudally to see for contour and architectural
abnormality.
45. • If pathology is encountered, then the attention is focused on
that particular segment.
• The probe is then turned in the long axis of the nerve and the
pathology is evaluated.
• Movement of limb helps to differentiate nerve from tendons,
whereas Color Doppler helps to differentiate nerves from
vessels.
• Lymph nodes are spherical and show a fatty hilum and can be
easily differentiated from nerves by their shape and inability
to trace them in longitudinal axis.
46. • The Normal nerve :
– Transverse section - reveals small hypoechoic areas
separated by hyperechoic septae, giving a “honeycomb-
like” appearance. The hypoechoic areas represent nerve
fascicles while the echogenic septae represent
interfascicular perineurium.
– Longitudinal sections - also reveal the fascicular
architecture, leading to a “bundle of straws” appearance.
– Normaly nerves have no detectable doppler flow (unless
injured or streched).
47. • Nerve is more echogenic compared to the muscle which
shows hypoechoic muscle fiber bundles with intervening
echogenic perimysium.
• The tendon more echogenic as compared to the nerve and
shows a compact arrangement of echogenic fibrils.
48. • Zaidman et al. (NEUROLOGY 2013) :
– Retrospectively compared accuracy of ultrasound and MRI
for detecting focal peripheral nerve pathology, excluding
idiopathic Carpal or Cubital tunnel syndromes.
– Ultrasound is more sensitive than MRI (93% vs 67%), has
equivalent specificity (86%), and better identifies
multifocal lesions than MRI.
– In sonographically accessible regions ultrasound is the
preferred initial imaging modality for anatomic evaluation
of suspected peripheral nervous system lesions.
49. Axial USG image of normal nerve showing rounded hypoechoic areas separated by
hyperechoic septae, giving a “Honeycomb” appearance
50. Longitudinal USG image of normal nerve depicting hypoechoic linear fascicles with
intervening echogenic interfascicular perineurium i.e. “Bundle of straws” appearance
52. 1. TRAUMA
• Nerve injuries are broadly classified as : Neurapraxia,
Axonotmesis, and Neurotmesis.
• Neurapraxia is injury with maintenance of nerve continuity.
• Axonotmesis is disruption of axons and myelin with intact
epi-and perineurium
• Neurotmesis is complete disruption of the nerve.
• Neurapraxia and axonotmesis have good chances of
recovery, while neurotmesis does not usually recover
without surgery
53. • USG can be used to detect and demonstrate :-
– the site of injury
– differentiate nerve injury in continuity from nerve
transaction
– evaluate the cause of compression, and
– detect foreign bodies as well as neuroma or scarring.
• USG also useful in localizing iatrogenic nerve injury following
limb lengthening procedures or due to orthopedic implants
where magnetic resonance imaging (MRI) may be limited
due to susceptibility artifacts.
54. • High resolution USG allows evaluation of small nerves like
digital nerves which may be difficult with MRI.
• Also, MRI may not differentiate neural contusion from nerve
disruption.
• Electrodiagnostic studies do not demonstrate morphologic
information like site and degree of injury. Hence, USG has an
important role to play in evaluation of patients with suspected
nerve injury.
55. • Neurapraxic injury is seen as swollen nerve with hypoechoic
appearance.
• Complete and partial transection of nerves can be
differentiated by USG.
• In cases with transection, it is important to provide the
distance between the stumps as it helps in deciding surgical
management.
• Stump or amputation neuromas (reactive thickening of the
nerves and not true tumors) may be seen as focal thickening
or mass-like lesions at the nerve ends .
56. (A) Longitudinal and (B) axial USG images in a patient with previous history of fracture
repair of humerus at the elbow. The K wire is impinging on the nerve, causing chronic
nerve degeneration seen as hypoechoic appearance of nerve with loss of normal
fascicular architecture
57. Longitudinal USG image reveals complete transection of the volar digital nerve of
middle finger following penetrating injury
58. Longitudinal USG image shows complete transection of the radial nerve following old
penetrating trauma.
Note the Amputation neuromas at both the cut ends seen as bulbous lesions
59. 2. TUMORS
• Most common nerve tumors are nerve sheath tumors which
include Schwannomas and Neurofibromas.
• It may not always be possible to differentiate between them
on USG.
• Seen as well-defined ovoid homogeneous hypoechoic lesions
with nerve entering and exiting from them.
• Schwannomas are eccentric along the long axis of nerve, with
nerve fascicles seen separately.
• Neurofibromas are spindle-shaped with loss of normal
fascicular architecture
60. (A) Longitudinal USG image showing a fusiform predominantly hypoechoic mass lesion
along the median nerve in forearm. The nerve can be located eccentrically along the
ventral aspect of the mass lesion, suggesting the diagnosis of Schwannoma
(B) Intraoperative image of the lesion confirming the ultrasound findings
(C) Intraoperative image after excision of the mass lesion with preservation of the nerve
61. 3. INFECTIVE LESIONS
• In India, leprosy is a common treatable condition whose
hallmark is nerve enlargement and inflammation.
• Clinical examination may be subjective and inaccurate.
• Also, many nerves may not be amenable to palpation.
• Early detection of nerve impairment can help in preventing
disability.
• USG can provide objective evidence of nerve enlargement and
also evaluate its internal architecture.
• In leprosy, the nerves may show enlargement as well as
edema, loss of fascicular architecture, and increased peri- and
endoneurium vascularity on Doppler.
• Jain et al. have demonstrated these changes in ulnar, median,
lateral peroneal, and popliteal nerves.
62. (A) Longitudinal USG image and (B) Color Doppler image of median nerve in a patient
with leprosy. The entire nerve is thickened with loss of fascicular architecture and
hypoechoic appearance. There is increased endoneurium and perineurium vascularity
on color Doppler
63. 4. ENTRAPMENT NEUROPATHIES
• Often unrecognized cause of pain and neural impairment.
• The nerves are more prone to compression in specific
locations where they course through osteofibrous tunnels.
• The median nerve in carpal tunnel and the ulnar nerve in
Guyon's canal and cubital tunnel are the common sites of
entrapment in the upper limb and can be evaluated with USG.
• Common peroneal nerve near fibular neck and posterior tibial
nerve in tarsal tunnel are commonly involved in the lower
limb.
64. • Carpal tunnel syndrome - most common entrapment
neuropathy.
• Occurs due to compression of the median nerve in the carpal
tunnel bounded by the carpal bones and the flexor
retinaculum.
• The diagnosis is based on the patient's history of sensory and
motor symptoms in median nerve distribution and clinical
examination findings.
• USG is comparable with nerve conduction studies in the
diagnosis of carpal tunnel syndrome.
• It shows the classic triad of (Buchberger et al) :-
– enlargement of the nerve at the level of distal radius and
proximal carpal tunnel
– flattening of the nerve in distal carpal tunnel and
– palmar bowing of the flexor retinaculum.
65. • A cross-sectional area of the median nerve proximal to the
tunnel inlet more than 10 mm2 is abnormal.
• The abrupt change in nerve caliber at the entrance of carpal
tunnel is called “notch sign”.
• The nerve may show a homogeneous hypoechoic appearance
with loss of fascicular echopattern
• A contralateral comparison usually helps in detecting subtle
signs to reach the diagnosis.
66. Longitudinal USG image of Normal median nerve proximal to and in the carpal tunnel.
T: Flexor tendons in the carpal tunnel; MN: Median nerve
67. (A) Longitudinal USG image shows enlargement of the median nerve at carpal tunnel
inlet and outlet in carpal tunnel syndrome.
(B) Axial USG image shows increase in cross-sectional area of the median nerve proximal
to the tunnel. It is 12.6 mm2 .Normal being less than 10 mm2
68. (A) Longitudinal USG image reveals abrupt change in the caliber of median nerve at
the entrance of carpal tunnel (Notch sign) in carpal tunnel syndrome.
(B) Intraoperative image confirming the ultrasound findings
70. REFERENCES
• Transcranial Doppler Ultrasound: Technique and Application :
Sushmita Purkayastha, Farzaneh Sorond : Seminars in
Neurology 2012;32:411–420.
• Textbook of Emergency Neuroradiology : T Scarabino
• Role of ultrasound in evaluation of peripheral nerves : Ashwin
D et al : Indian J Radiol Imaging. 2014 Jul-Sep; 24(3): 254–258.
• High-Resolution Sonography of Lower Extremity Peripheral
Nerves: Anatomic Correlation and Spectrum of Disease :
Siegfried Peer et al : J Ultrasound Med 21:315–322, 2002
• Sonography of Peripheral Nerve Pathology : R. M. Stuart et al :
American Journal of Roentgenology. 2004;182: 123-129.
• Bradley’s Neurology in clinical Practice : 7th edition