1) Carotid Doppler ultrasound is used to evaluate the carotid arteries for stenosis or occlusion. It involves using grayscale, color Doppler, and spectral Doppler to examine the anatomy and flow of the carotid arteries.
2) A normal carotid Doppler ultrasound will show triphasic waveforms within the carotid arteries with velocities under 125 cm/sec. The intima-media thickness should be less than 0.8-0.9mm.
3) Carotid artery disease is most commonly caused by atherosclerosis which can be evaluated using Doppler ultrasound parameters like peak systolic velocity, end diastolic velocity, and ICA/CCA velocity ratios to grade the severity of stenosis.
In this part of presentation we will discuss the role of Doppler Ultrasound in the Diagnosis of other causes of stenosis and variable pattern in circulation.
In my opinion this presentation will help u to identify even rare pathologies.
In this part of presentation we will discuss the role of Doppler Ultrasound in the Diagnosis of other causes of stenosis and variable pattern in circulation.
In my opinion this presentation will help u to identify even rare pathologies.
Doppler ultrasound of visceral arteriesSamir Haffar
Doppler ultrasound of different diseases of visceral arteries including arterial stenosis and occlusion, arterial aneurysm, artrial pseudoaneurysm, arterio-venous fistula, artrial dissection, and abdominal vascular compression syndromes
Role of medical imaging in management of arteriovenous fistula Dr. Muhammad B...Dr. Muhammad Bin Zulfiqar
This presentation is very helpful for vascular sergeons, interventional radiologists and sonographers that how to map Vasculature before construction of AV fistula for hemodialysis, how to check its patency, how to check its proper functioning ,to comment on its failure and decide when to reintervene.
Doppler ultrasound of visceral arteriesSamir Haffar
Doppler ultrasound of different diseases of visceral arteries including arterial stenosis and occlusion, arterial aneurysm, artrial pseudoaneurysm, arterio-venous fistula, artrial dissection, and abdominal vascular compression syndromes
Role of medical imaging in management of arteriovenous fistula Dr. Muhammad B...Dr. Muhammad Bin Zulfiqar
This presentation is very helpful for vascular sergeons, interventional radiologists and sonographers that how to map Vasculature before construction of AV fistula for hemodialysis, how to check its patency, how to check its proper functioning ,to comment on its failure and decide when to reintervene.
Fundamentals of Vascular Ultrasound.
Looking at the basics of carotid, lower extremity arterial, renal, celiac, SMA studies, as well as touching on venous insufficiency. Part I of series.
Basics of Coronary Angiography Hewad Gulzai.pptxHewad Gulzai
Basics of Coronary Angiography for beginners, MD, DNB, DM students, Nurses, cathlab technicians, physicians and other healthcare members .
hope you will learn something from this ppt. 😀
Dislocation of joint is very tricky. In this presentation radiological evaluation of Dislocation of various joints will be discussed.
This is one of the best pictoral review of important joint dislocations
Renal Color Doppler Ultrasound.
After studying this presentation one will be able to perform and interpret ultrasound.
This presntation in my opinion is best short analog to text.
In this presentation we will discuss the bone age assessment mainly focusing wrist radiograph.
we shall also highlights some points in adult bone age
Basically it is an introduction. We shall not discuss its judicial importance
Role of medical imaging in developemental dysplasia of Hip Dr muhammad Bin Zu...Dr. Muhammad Bin Zulfiqar
In this presentation we will discuss the role of medical imaging---plain Radiography, Ultrasound,Arthrography, CT and MRI in the evaluation of Developemental dysplasia of hip. Our main focuss will be on Sonographic evaluation.
In this presentation we will discuss the basic of axial trauma from head to pelvis. We will discuss the important key points that aids in the diagnosis of axial trauma
This is a chapter from Grainger and Allison. I have Coolected all images from chapter 21 with caption in this presentation.
In my opinion it will be very benificial to have this in your android.
This presentation is the first series of the MR imaging of Knee.
In this presentation MRI anatomy has been discussed. As we all know good knowledge of medical imaging three dimensional anatomy is key for good reporting.
Hope we all get benifitted.
Suggestions are most welcome
This is a chapter from Grainger and Allison. I have Coolected all images from chapter 20 with caption in this presentation.
In my opinion it will be very benificial to have this in your android. ,
This presentation is almost a complete Pictoral view of Radiograph chest.
This presentation will help radiologist in daily reporting.
This presentation will help physicians, surgeons, anesthetist and almost all medical professionals in diagnosing commonly presenting cardiac diseases.
This will also help all in preparaing TOACS examination.
This is a chapter from Grainger and Allison. I have Coolected all images from chapter 19 with caption in this presentation.
In my opinion it will be very benificial to have this in your android. ,
In this presentation we will dscuss the imp imaging features of Posterior fossa tumors in pediatric age group.
Medulloblastoma
Pilocytic Astrocytoma
Ependymoma
Brainstem Glioma
Schwanoma
Meningioma
Epidermoid Cyst
Arachnoid Cyst
In this presentation we will discuss about the
Anatomy of Prostate
Technique of Transrectal US
Carcinoma Prostate and
Different modes of prostatic biopsy.
In this presentation we shall discuss all fractures with specific names .
This is a pictoral review.
This presentation will be very helpful for radiologist to have in their androids to help them in rapid reporting
In this presentation all images of Chapter 18 from Grainger and Allison have been discussed.
Our aim is to discuss authentic material .
This is only for educational purposes.
In this chapter air space infilteration have been discussed. Ground glass haze and consolidation are discussed in detail.
This presentation is a selection of images from 17th chapter of grainger and allison.
Our aim is to provide standard and proved cases of the disease process.
This all is for educational purpose
Objectives of this presentation are
Introduction to ct
Cross sectional anatomy
Common important pathologies
This presentation is aimed to educate beginers to help in ct interpretetion.
16 High Resolution Computed Tomography of Interstitial and Occupational Lung ...Dr. Muhammad Bin Zulfiqar
This presentation is collection of images from chapter 16 of Grainger and Allison.
Inthis we will discuss the ILD.
This is only for educational purposes.
This Presentation is a collection of chapter 5 images from Grainger and Allison.
Our aim is to study authentic data.
This is only for educational purposes
In this presentation we will discuss role of high resolution in characterizing normal variant and pathologies of spinal pathologies.
This is a pictoral review.
This presentation provides sufficient material for anyone who wants is interested in interventional radiology. Here we will discuss the available facilities, mechanisms and equipments.
In my opinion this presentation will prove a footstep in interventional radiology
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
2. Doppler US of carotid arteries
Anatomy of carotid arteries
Normal Doppler US of carotid arteries
Causes of carotid artery disease
Effect of extra-carotid diseases
3. PART I
Anatomy of carotid arteries
Normal Doppler US of carotid arteries
Causes of carotid artery disease
• Common Carotid Artery
• Internal Carotid Artery
• External carotid Artery
4. Extra cranial cerebral arteries
All arteries that carry blood from heart up to base of skull
Right & left sides of extra cranial circulation not symmetrical
6. Variations in extracranial circulation
Few
• Left CCA & SCA share single trunk
• Left vertebral artery arising directly from aortic arch
• Right vertebral origin arising directly from aortic arch
7. Vertebral artery course
V1
V0
V2
V3
V4
BA
VAs asymmetric in 75 % – Left dominant in 80 %
Posteriorly directed loop when exists C1 transverse process
2 VAs units to form basilar artery: collateralization
8. Doppler US of carotid arteries
Anatomy of carotid arteries
Normal Doppler US of carotid arteries
Causes of carotid artery disease
Effect of extra-carotid diseases
9. All carotid artery examinations should be
performed with:
Tahmasebpour HR et al. RadioGraphics 2005 ; 25 : 1561 – 1575.
• Gray-scale US
• Color Doppler
• Power Doppler
• Spectral Doppler
Integrate gray scale, color flow, & spectral findings
10. Position for scanning the carotid arteries
Patient lie down in supine or semisupine position
Head hyperextended & rotated 45° away from side being examined
Higher-frequency linear transducers (≥ 7.5 MHz)
11. Doppler ultrasound of carotid arteries / Tips
• Begin each scan on same side, usually the right
• Avoid excess pressure on carotid bifurcation to avoid
– Stimulate carotid sinus Bradycardia
Syncope
Ventricular asystole
– Compress arteries to cause spurious high velocities
16. Normal flow reversal zone in ICA
Velocities highest near flow divider
Flow reversal on opposite side
to flow divider
Flow reversal zone
Opposite to origin of ECA
17. Internal & external carotid artery
2 small branches originating from ECA
Power Doppler US
19. Typical normal Doppler spectra
Common carotid artery
Internal carotid artery
External carotid artery
Triphasic pattern
Dicrotic notch
PSV: 45 – 125 cm/sec
Difference between 2 sides < 15 cm/sec
20. Dicrotic notch
Normal feature
Closure of aortic valve with temporary cessation of forward flow
Resumption of forward flow by elastic rebound of aortic wall
22. Abnormal Doppler flow in tortuous vessel
Tortuous CCA displays color
Doppler eccentric jets of flow
High velocity due to eccentric
jet in tortuous CCA
Tortuosity can increase velocity, although there is no stenosis
Try sampling just beyond the curve
23. Temporal tapping of ECA
“Saw-tooth” appearance
Small regular deflections (TT)
Frequency corresponds to rate of temporal tapping
Deflections best seen during diastole
24. Differentiation between ICA & ECA
Features ICA ECA
Size Usually larger Usually smaller
Temporal tap Usually negative Usually positive
Pulsed Doppler Low resistance High resistance
Orientation Posterior Anterior
Branches Rarely Yes
25. Protocol for VA examination
– Direction of flow
– Waveform configuration
– Measure PSV
Longitudinal VA between transverse processes
Caudad survey
– Follow artery cauded to its origin
Cephalad survey
– Follow artery cephalad above transverse processes
26. Ultrasound of normal vertebral vessels
Cephalad flow throughout cardiac cycle
Low resistance flow pattern
VA origin regularly seen by experienced sonographers
Size: variable & asymmetric – Mean diameter 4 mm
PSV: 20 – 40 cm/sec – <10 cm/sec potentially abnormal
Vertebral artery
Vertebral vein
May occasionally be seen adjacent to VA
Flow caudad & nonpulsatile
30. Doppler US of carotid arteries
Anatomy of carotid arteries
Normal Doppler US of carotid arteries
Causes of carotid artery disease
Effect of extra-carotid diseases
31. Causes of carotid artery diseases
Arteriosclerotic disease
Non-arteriosclerotic diseases
Fibro muscular dysplasia
Dissection
Vasospasm
Aneurysm & pseudo aneurysm
Arterio-venous fistula
Arteritis: Takayasu – Horton
Carotid body tumor
Idiopathic carotidynia
Most common cause
32. Extracranial carotid artery & stroke
• Stroke is third leading cause of death in USA
• > 500,000 new cases of CVA reported annually
• 20 – 30% of stokes due to severe carotid artery stenosis
• Stenosis involves ICA within 2 cm of bifurcation
• CEA* more beneficial than medical tm in symptomatic
or asymptomatic patients with > 70% carotid
stenosis**
* CEA: Carotid endarterectomy
** NASCET: North American Symptomatic Carotid Endartectomy Trial
** ECST: European Carotid Surgery Trial
33. Common sites for extracranial arterial disease
Most common site at carotid bifurcation
with plaque extending into ICA
34. Plaque characterization
Low Lipid – Flow void
Moderate Collagen – Easy to see
High with shadow Calcification – Focal or diffuse
Echogenicity
Calcification: no correlation with neurologic symptoms
Focal hypoechoic zones: Hemorrhage – Necrosis – Lipid
Heterogenous plaque
Common sources of cerebral emboli: TIA – Stroke
Poor US results for ulcer detection
Plaque surface features
36. Calcified plaque
Calcific plaque with shadow
obscuring portion of the bulb
Interrogate artery beyond plaque
Shadowing segment < 1 cm
No turbulent flow: insignificant stenosis
Damped or turbulent flow: tight stenosis
Shadowing segment > 2 cm
Degree of stenosis indeterminate
Other modalities recommended
38. Sources of error in ulcer diagnosis
Plaque surface irregular
but not ulcerated
Adjacent plaque
simulate ulceration
Image plan does not include
the ulcer
40. Ulcerated plaque or twinkle artifact
Scale 86 cm/sec, color in diastole
Color flow disappeared
Color artifact continues to twinkle
Hard plaque in proximal ICA
Questionable flow at plaque surface
47. ICA stenosis on angiogram
ECST 2 (1998)
European Carotid Surgery Trial
(C – A / C) x 100
NASCET 1 (1991 – 1998)
North American Symptomatic Carotid Endartectomy Trial
(B – A / B) x 100
48. ICA stenosis on angiogram
Diameter reduction
* NASCET: North American Symptomatic Carotid Endartectomy Trial
** ECST: European Carotid Surgery Trial
30% 65%
40% 70%
50% 75%
60% 80%
70% 85%
80% 91%
90% 97%
* NASCET
(B – A / B) x 100
** ECST
(C – A / C) x 100
51. Aliasing or high velocity jet
Area of highest velocity in area of stenosis
52. Adjustment of color gain
Color gain at 80%
Marked turbulence of ICA & ECA
No luminal narrowing
Anatomy of bifurcation
demonstrated more accurately
Color gain at 66%
54. Color Doppler bruit
Extensive soft tissue color Doppler bruit surrounds
carotid bifurcation with 90% ICA stenosis
Confetti sign
55. Post stenotic zone/ Immediately after stenosis
• Cannot be precisely quantified (evaluated visually)
Fill-in of spectral window > 50% diameter
reduction
Severely disturbed flow > 70% diameter
reduction
High amplitude & low frequency Doppler signal
Flow reversal
Poor definition of spectral border
• May be only sign of carotid stenosis in calcified plaque
Spectral broadening
56. Spectral broadening
Immediately after stenosis
High amplitude & low frequency Doppler signal
Poor definition of spectral border
Flow reversal
Severe spectral broadening: > 70% diameter reduction
57. Pseudo-spectral broadening
• High gain setting
• Vessel wall motion
• Tortuous vessels
• Site of branching
• Abrupt change in vessel diameter
• ↑ velocity: athlete - high cardiac output - AVF1 - AVM2
• Aneurysm, dissection, & FMD3
1AVF: Arterio-Venous Fistula
2AVM: Arterio-Venous Malformation
3FMD: Fibro-Muscular Dysplasia
59. Sonographic features of severe ICA stenosis
Significant visible plaque (≥ 70% diameter reduction)
PSV > 230 cm/sec
EDV > 100 cm/sec
ICA/CCA PSV ratio ≥ 4.0
Spectral broadening
Color aliasing despite high velocity scale (100 cm/sec)
Color bruit artifact in surrounding tissue of stenosis
High-pitched sound at pulsed Doppler
60. Tight stenosis or occlusion?
• Difficult to distinguish tight stenosis from occlusion
• Completely occluded ICA
Will not release emboli
Not corrected by surgery
• Very severe stenosis
Potential source for emboli or acute thrombosis
May require urgent surgery
61. Optimization of low flow velocities
• Decreased color velocity scale
• Increase color, power & pulsed Doppler gain
• Decreased wall filter
• Focal zone at level of diseased segment
• Doppler angle as low as possible (60° or less)
• Increased persistence
• Increase sample volume gate
62. Subtotal occlusion of ICA
“string sign” or “trickle flow ”
Narrow channel of low-velocity in subtotal ICA occlusion
Low PRF & low filter required to detect low-velocity flow
63. High grade “string sign” stenosis
Tardus Parvus waveform
Tardus: Long rise time
Parvus: Low PSV
64. Endarterectomy without arteriography
• Arteriography Expensive
Risks: stroke (0.1 – 0.6%) – death (0.1%)
Rarely affect surgical plan
Sufficient information obtained with MRI
• Conditions Good experience of US department
Stenosis localized to carotid bifurcation
Unequivocal US findings
Symptoms ipsilateral to carotid stenosis
65. Causes of image/Doppler mismatch
• Cardiac arrhythmia
• Severe aortic stenosis
• Hypotension or hypertension
• Tortuous vessels
• Hypoechoic, anechoic or calcified plaques
• Long segment high grade stenosis
• Pre-occlusive lesion
• Tandem lesion
• Contra-lateral carotid stenosis
• Carotid dissection
66. Short & long stenosis of ICA
Short stenosis (frequent) Long stenosis (rare)
PSV lower than expected
EDV maintained at high level
Can produce very high PSV
(> 500 cm/s)
67. Long stenosis of ICA
Zwiebel WJ et al. Ultrasound Quarterly 2005 ; 21 : 113 – 122.
RICA
RICA: PSV 183 cm/sec
EDV 105 cm/sec
CCA: PSV 76 cm/sec
PSV ratio: 2.4
Inconsistent data
Long stenosis of ICA > 70%
68. Occlusion of ICA
• Absence of flow by color, power & pulsed Doppler
• “Internalization” of ipsilateral ECA waveform
• Reversed flow in ICA or CCA proximal to occlusion
• Thrombus or plaque completely fills lumen of ICA
• Externalization of ipsilateral CCA or proximal ICA
• Higher velocities in contralateral CCA vs. ipsilateral CCA
70. Occlusion of ICA
“to-and-fro” flow or thud flow
Tahmasebpour HR et al. RadioGraphics 2005 ; 25 : 1561 – 1575.
Damped systolic flow
Reversed flow in early diastole
Pulsed Doppler of CCA
72. Occlusion of CCA
Robbin ML et al. Ultrasound Clin 2006 ; 1 : 111 – 131.
Reversed flow from ECA
to supply ICA & brain
“ECA-to-ICA collateralization”
73. Occlusion of CCA
Tahmasebpour HR et al. RadioGraphics 2005 ; 25 : 1561 – 1575.
Absence of flow in distal CCA
Reversed flow in ECA
Normal flow in ICA
Internalization of ECA
Delayed systolic acceleration (Tardus)
Positive temporal tap maneuver
CCA, which has no branches, divides into the internal and external carotid arteries.Carotid artery widens at the level of the bifurcation to form the carotid bulb & degree of widening of carotid bulb is quite variable.Level of the carotid bifurcation in the neck is highly variable.Proximal branches of the ECA are the superior thyroid, lingual, facial and maxillary arteries.Vertebral artery is the first branch of the subclavian artery, arising from the highest point of the subclavian arch. At the sixth cervical vertebra, the vertebral artery runs posteriorly to travel upward through the transverse foramen of cervical vertebrae.Two vertebral arteries join, at the base of the skull, to form basilar artery, which then divides to form posterior cerebral arteries.
Tortuosity can cause apparent velocity increase even although there is no stenosis. This is due to difficulty in obtaining a correct insonating angle, non-linear or helical flow, or increased velocityon the inside of the curve. Try sampling just beyond the curve.
“Saw-tooth” appearance: مظهر أسنان المنشار
Endarterectomy decrease the risk of ipsi-lateral hemispheric stroke or death by 53 to 84% as compared to medical treatment.
Cauliflower: قرنبيط
Eddy: دوامة
A panel of experts from a variety of medical specialties was convened under the auspices of the Society of Radiologists in Ultrasound to arrive at a consensus about the performance of Doppler ultrasonography (US) to aid in diagnosis of internal carotid artery (ICA)stenosis. The panel met in San Francisco, Calif, October 22–23, 2002, and drew up a consensus statement. Although there are several facets of carotid disease that could be considered by such a panel, carotid stenosis (and by extension, carotid occlusion) is by far the most common pathologic process involving carotid arteries.The panel consisted of a moderator and 16 panelists from various medical specialties.
the method used to report the degree of narrowing from an angiogram differed between the European and North American trials.In the ECST trial, the degree of stenosis was measured by comparing the residual lumen diameter with the estimated diameter of the carotid bulb, whereas the NASCET trial compared the residual lumen diameter with the diameter of the normal distal ICA.
In the North American Symptomatic Carotid Endartectomy Trial, the narrowest portion of the vascular lumen was compared with the “normalized lumen distally”.In the European Symptomatic Carotid Trial study and studies performed prior to the NASCET study, the degree of stenosis was determined by comparing the narrowest diameter of the residual lumen to an estimate of the original lumen in the same area. Because the original lumen cannot be depicted on the angiogram, exact measurement is impossible.The panel recommended that the NASCET method of carotid stenosis measurement should be employed when angiography is used to correlate the US findings. While the NASCET method of measurement may not reflect the burden of atherosclerosis in the proximal ICA, it does minimize the amount of interobserver variability.
Stringsign stenosis(Figure 15a. Circumferential calcified plaque in the proximal ICA. (a) PW Doppler image of the right ICA obtained immediately distal to a circumferential shadowing plaque shows no sign of turbulence, and the PSV is within normal limits. Therefore, there is unlikely to be a significant stenosis behind the calcified plaque. (b) PW Doppler image of the proximal right ICA shows a tardus-parvus waveform. A severe proximal stenosis behind the shadowing plaque is suspected; therefore, evaluation with another imaging modality is required. (c) PW Doppler image of the right ICA shows spectral broadening (turbulence) with an elevated PSV. These results may be due to a high degree of stenosis immediately proximal to the point of sampling; therefore, further investigation with another imaging modality is required. )
Long stenosis: > 2 cm
It can be difficult to distinguish tight stenosis from occlusion. A completely occluded ICA cannot be corrected by surgery and will not release emboli. However, very severe stenosis can be a potential source for emboli or acute thrombosis and may require urgent surgery.
Thud: صوت مكتوم
The ECA is an important collateral pathway in patients with ipsilateral ICA occlusion and recurrent symptoms.This may influence the surgical decisions involving revascularization of the stenotic ECA.