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Year : 2018 | Volume : 6 | Issue : 2 | Page : 74 - 78  


Original Articles
Carotid artery evaluation in ischemic stroke patients using Color Doppler imaging

Jyotsna Katuri1, Anindita Mishra2*

1Resident, 2Professor &HOD, Department of Radio diagnosis, GSL Medical College, Rajahmundry, Andhra Pradesh

Corresponding Author*

Email: dr.aninditamishra@gmail.com

Abstract:

Background: Stroke is a major cause of mortality, morbidity, & health care expenditure globally. Carotid artery stenosis accounts for approximately 85% of all strokes. There is great value of safe, noninvasive and low cost screening test; therefore Doppler ultrasound study of carotid system is an important modality. Duplex Sonography, combining high resolution imaging and Doppler spectrum analysis has proved to be popular, non invasive, accurate and cost effective means of assessing carotid artery disease.

Objective: 1.To assess carotid arteries with the help of color Doppler and -B mode imaging in carotid artery disease. 2. To correlate cerebrovascular accidents with extra cranial carotid artery status.

Methods: This study was carried out in patients who had symptoms and signs of strokes, or transient ischemic attacks at a tertiary teaching hospital from the period of January 2015 to June 2016. The study was carried out on 94 patients. A detailed clinical history was taken and clinical examination findings were recorded. Risk factors like hypertension, diabetes mellitus, smoking and ischemic heart disease were documented. CT scan examination of the brain was carried out in all the patients and the findings were noted.

Results: In this study, 79% of the patients were males and only 21% were females. The highest number of stroke patients in our study was found in the age group of 50-59 years which was 28%. Around 17% of patients had right MCA territory infarct, 9% had Left MCA territory infarct. Lacunar infarcts were seen in 33% patients. About 3% patients had right ACA territory infarct, 2% patients had left ACA infarct, 2%patients had right cerebellar infarct & 5% patients have age related cerebral atrophy. Normal study of brain was found in 25 patients in this study, 63% of patients had plaque in the carotid system. 47% of patients had plaque on the right side, 41% patients had plaque on the left side and 12% patients had bilateral involvement.

Conclusion: Color Doppler examination is an economic, safe, reproducible and less time consuming method of demonstrating the cause of cerebrovascular insufficiency in the extra cranial carotid artery system and will guide in instituting treatment modalities.

Keywords: Stroke, Color Doppler, Carotid arteries, risk factors

Introduction:

Background: Stroke is a major cause of mortality, morbidity, & health care expenditure globally. Carotid artery stenosis accounts for approximately 85% of all strokes. There is great value of safe, noninvasive and low cost screening test; therefore Doppler ultrasound study of carotid system is an important modality. Duplex Sonography, combining high resolution imaging and Doppler spectrum analysis has proved to be popular, non invasive, accurate and cost effective means of assessing carotid artery disease.

Objective: 1.To assess carotid arteries with the help of color Doppler and -B mode imaging in carotid artery disease. 2. To correlate cerebrovascular accidents with extra cranial carotid artery status.

Methods: This study was carried out in patients who had symptoms and signs of strokes, or transient ischemic attacks at a tertiary teaching hospital from the period of January 2015 to June 2016. The study was carried out on 94 patients. A detailed clinical history was taken and clinical examination findings were recorded. Risk factors like hypertension, diabetes mellitus, smoking and ischemic heart disease were documented. CT scan examination of the brain was carried out in all the patients and the findings were noted.

Results: In this study, 79% of the patients were males and only 21% were females. The highest number of stroke patients in our study was found in the age group of 50-59 years which was 28%. Around 17% of patients had right MCA territory infarct, 9% had Left MCA territory infarct. Lacunar infarcts were seen in 33% patients. About 3% patients had right ACA territory infarct, 2% patients had left ACA infarct, 2%patients had right cerebellar infarct & 5% patients have age related cerebral atrophy. Normal study of brain was found in 25 patients in this study, 63% of patients had plaque in the carotid system. 47% of patients had plaque on the right side, 41% patients had plaque on the left side and 12% patients had bilateral involvement.

Conclusion: Color Doppler examination is an economic, safe, reproducible and less time consuming method of demonstrating the cause of cerebrovascular insufficiency in the extra cranial carotid artery system and will guide in instituting treatment modalities.

Keywords: Stroke, Color Doppler, Carotid arteries, risk factors

Methods:

This study was carried out in patients who had symptoms and signs of strokes, or transient ischemic attacks at GSL Medical college hospital, Rajahmundry from the period of January 2015 to June 2016. The study was carried out on 94 patients. A detailed clinical history was taken and clinical examination findings were recorded. Risk factors like hypertension, diabetes mellitus, smoking and ischemic heart disease were documented. CT scan examination of the brain was carried out in all the patients and the findings were noted. The data gathered from the color Doppler examination consisted of:

  • ƒ Peak Systolic velocity of common carotid artery
  • ƒ Peak systolic velocity of internal carotid artery
  • ƒ Velocity ratios between internal carotid artery and common carotid artery
  • ƒ Plaque characteristics as seen on the real time image
  • ƒ The presence of Spectral broadening.

All the examination was performed with a Doppler angle of 60 degrees. Color Doppler examination of the carotid arteries was done using Philips HD 7 Color Doppler with 11MHz linear array electronic transducer.

Examination Technique: Carotid arteries were examined with patient in the supine position. Neck exposure was enhanced by tilting and rotating the head away from the side being examined, and ipsilateral shoulder was dropped as far as possible. The examiner was seated at the right side of the patient.

The postero-lateral and far posterolateral transducer positions were used to examine the carotid arteries in long axis (longitudinal). Short axis (transverse) views of the carotid arteries were obtained from an anterior, lateral or posterolateral approach.

The Examination Sequence: The first step began with a longitudinal survey of the cervical carotid arteries, with the transducer in a lateral position. The common carotid artery was identified at the clavicle, and the transducer was moved cephalad along the artery until the carotid bifurcation was seen. The location of the bifurcation was then ascertained by shifting back and forth between the internal and external carotid branches. The internal carotid artery was followed as cephalad as possible using a posterolateral transducer position. The location of plaque and major points of obstruction are noted during survey examinations.

In the second step, each abnormal area was scrutinized for the extent of plaque formation, internal plaque characterization and degree of luminal narrowing was noted (from Color Doppler and spectral Doppler information). The detailed examination of atheromatous lesions was initially conducted from a lateral and posterolateral transducer position.

In the third step, carotid arteries were re-examined from an anterior transducer position, which was roughly at right angles to the other longitudinal positions. The plaque was re-evaluated from this position.

In the fourth step, when the longitudinal examination was completed, the carotid vessels were studied from transverse position. At the carotid bifurcation, the identity of the internal and external carotid branches was confirmed by web form analysis. The location of plaque and stenosis (common, external or internal carotid segments) was reaffirmed. Visual or Doppler assessment of stenosis severity were done.

Results:

The present study was done to evaluate the extra cranial carotid arterial system in the population who presented with stroke. About 74 patients out of 94 (79%) of the patients were males and 21 out of 94 (21%) were females.

Highest number of stroke patients were found in the age group of 50-59 years which was 27 out of 94 (28%) followed by the age group between 40-49 years which was 21% i.e. 20 out of 94 patients(Table 1).

Out of the 94 patients studied, 36(38.3%) patients had right sided stroke, 42 (45%) patients had left sided stroke. Bilateral involvement was seen in 3 (3%) patients and 13 (14%) patients had transient ischemic attack (Graph 1).

According to CT scan findings, 16(17%) patients had right MCA territory infarct, 8 (9%) had Left MCA territory infarct (Table 2). Lacunar infarcts were seen in 31 (33%) patients. Only 3 (3%) patients had right ACA territory infarct, 2 (2%) patients had left ACA infarct, 2 (2%) patients had right cerebellar infarct & 5 (5%) patients have age related cerebral atrophy. Normal study of brain was found in 25 patients.

The risk factors that cause plaque formation and stroke were evaluated. Out of the total 94 patients, 37 (39%) patients had variable degree of hypertension out of which 5 (14%) had significant stenosis.

41 of the patients out of 94 (44%) had history of smoking. Out of them, 7 (17%) had significant stenosis. About 13 patients out of 94 (14%) had diabetes mellitus of which 6 (46%) had significant stenosis. Family history of stroke was present in 14 (15%) patients of which 4 (29%) showed significant stenosis (Graph 2).

Cardiac problem was ruled out among the study subjects who can interfere in the velocity profiles of the carotid system. The peak systolic velocity ratio of ICA / CCA was taken to define the percentage of significant stenosis. Out of 19 patients with significant stenosis (>50-69%), 7 (37%) patients had significant block on the right side, 7 (37%) had significant stenosis on the left side and bilateral significant block in 5 (26%) patients.

About 59 out of 94(63%) patients had plaque in the carotid system. 28 ( 47%) patients had plaque on the right side, 24 (41%) patients had plaque on the left side and 7(12%) patients had bilateral involvement (Table 3).

Internal carotid artery was found to be the commonest site affected by the plaque. In the right internal carotid artery plaques were found in 13 (22%) patients and in 14 (24%) patients on the left & bilateral in 5 (8%) patients. Plaques in carotid bulb were seen on the right side in 9(15%) patients and on the left side in 5 (8%). Plaques in the common carotid artery were also seen on the right side in 6 (10%) patients and 5 (8%) on the left side & bilateral in 2 (3%) patients (Graph 3).

In this study, 6 (21%) patients had homogenous plaques on the right side, 10 (17%) had non-homogeneous plaques and 21 (75%) patients were found to have calcified plaques. On the left side 5 (21%) patients had homogenous plaques, 12 (50%) had non homogenous plaques and 15 (62%) had calcified plaques.

Discussion:

Cerebrovascular disease is the third leading cause of death. About 30-60% of strokes are caused by atherosclerotic disease involving the extra cranial carotid arteries usually within 2 cm of carotid bifurcation. Angiography is gold standard but invasive and expensive and involves significant risk to the patients. Sonography is unique among vascular imaging procedures in that it can assess plaque composition which may have prognostic value and may be useful for selection of medical and surgical therapy.

The present study was done to evaluate the extra cranial carotid arterial system in the population who presented with stroke. Palomaki H et al studied the risk factors for cervical atherosclerosis in patients with ischemic stroke and transient ischemic attack and found that incidence of stroke increases after 60 years of age which is almost similar to the present study where the highest number of stroke patients in our study was found in the age group of 50-59 years which was 28%7. Lemolo F et al. in their study showed that only 2.5% of stroke victims were females whereas in our study, 21% were females. 8

The risk factors that cause plaque formation and stroke were evaluated. Carlene Lawes et al had studied 188000 patients with hypertension out of which 6800 had stroke events whereas in the present study, 39 % patients had variable degree of hypertension. 9 Ladecola et al had proved that control of blood pressure leads to a substantially lower risk of stroke10.Toshifumi Mannami et al confirmed a positive relationship between smoking and risk of stroke. 11 They estimated that 22% of stroke was attributable to smoking but 44% of patients in our study had history of smoking.

Diabetes mellitus is another risk factor for atherosclerosis. Lindberg Pertu and Roine Ristoin their study had observed that two thirds of all ischemic stroke types on admission had diabetes mellitus whereas in this study 14% patients had diabetes mellitus. 12 Schulz UGR, Flossmann E and Rothwell studied family history of stroke and found that 23% of stroke patients had positive family history. In this study family history of stroke was present in 14% of patients. 13

In the ultrasound literature different authors say that one or another of the 3 major Doppler parameters that is peak systolic velocity, end diastolic velocity or systolic velocity ratio is the most accurate predictor of clinically significant ICA stenosis.

In this study the peak systolic velocity ratio of ICA/CCA is taken to define the percentage of significant stenosis. Out of 19 patients with significant stenosis (> 50-69%), 7 (37%) patients had significant block on the right side, 7 (37%) had significant stenosis on the left side and bilateral significant block in 5 (26%) patients.

In our study 59 (63%) patients had plaque in the carotid system which is similar to the study by Schulte Altedorneburg G et al. 14 The commonest cause for obstruction is due to the atheromatous plaque. Schulte Altedorneburg G et al found steno occlusive carotid lesion in 64% of the patients studied. He also confirmed his findings by post mortem studies 14. Zwiebel WJ, found that the carotid bifurcation was commonly involved by the atherosclerotic plaque followed by the origin of carotid arteries whereas internal carotid artery was found to be the commonest site affected by the plaque in our study. 15

In our study, 21% of patients had homogenous plaques on the right side & 21% on the left side, 17%) had non-homogeneous plaques on right side & 50% of patients on left side. Aburahma Ali F, Wulu John T & Crotty Brad confirmed that soft plaques and non-homogeneous plaques are more positively correlated with symptoms than with any degree of stenosis and were the cause of adverse neurological events. 16

Limitation of the study: No histo-pathological correlation was done in our study because surgery was not done in any of the above patients.

Conclusion:

Color Doppler examination is an economic, safe, reproducible and less time consuming method of demonstrating the cause of cerebrovascular insufficiency in the extra cranial carotid artery system and will guide in instituting treatment modalities.

References:

  1. Carotid artery stenosis: Cost effectiveness of Assessment of Cerebrovascular Reserve to Guide Treatment of Asymptomatic Patients. by Dr Pandya et al RSNA 014.
  2. Stroke in India fact sheet by Fiona C Taylor, Suresh Kumar K, South Asian Network for Chronic Disease, IIPH Hyderabad, Public Health Foundation of India.
  3. Diagnostic ultrasound by Carol M Rumack , Stephane R Wilson, Debora Levine ,4th edition pg 949..
  4. Diaz J, Sempere AP. Cerebral ischemia: new risk factors. Cerebrovasc Dis 2004;17 Suppl 1:43-50.
  5. Ladecola Costantino, Gorelick Philip B. Hypertension, Angiotensin and stroke: Beyond blood pressure. Stroke 2003;35(2):348-50.
  6. Fulesdi B, Bereczki D, Mihalka L et al. Carotid atherosclerotic lesions in stroke patients with diabetes mellitus. Orv hetil 1999;140(13):697-700.
  7. Palomaki H, Kaste M, Raininko R et al. Risk factors for cervical atherosclerosis in patients with transient ischemic attack or minor ischemic stroke. Stroke 1993;24:970-5.
  8. Lemolo F, Martiniuk A, Dteinman DA, Spence JD. Sex differences in carotid plaque and stenosis. Stroke 2004;35(2):477-81
  9. Lawes C, Benett DA, Feigin VL, Anthony R. Blood pressure and stroke: An overview of published reviews. Stroke 2004;35(4):1024-33.
  10. Costantino L, Gorelick PB. Hypertension, angiotension and stroke: Beyond blood pressure. Stroke 2003;35(2):348-50.
  11. Mannami T, Iso H, Baba S et al. Cigarette smoking and risk of stroke and its sub types among middle aged Japanese men and women: The JPHC Study cohort 1: Stroke 2004;35(6):1248-53.
  12. Perttu P, Risto R. Hyperglycemia in acute stroke. Stroke 2004;35(2):363-4.
  13. Schulz UGR, Flossmann E, Rothwell P. Heritability of ischemic stroke to age, vascular risk factors, and subtypes of incident stroke in population based studies. Stroke 2004;35(4):819-24
  14. Schulte AG, Droste DW, Felszeghy S et al. Detection of carotid artery stenosis by in vivo duplex ultrasound. Stroke 2002;33(10):2402
  15. Zweibel WJ. Normal carotid arteries and carotid examination technique: Chapter 8 in Introduction to vascular ultrasonography, 4th ed, W.B. Saunders Company 2000: 113-118.
  16. Aburahma Ali F, Wulu John T, CrottyBrad. Carotid plaque ultrasonic heterogeneity and severity of Stenosis. Stroke 2002;33:1772.

Table 1: Age distribution among the stroke patients

AGE GROUP

  1. OF PATIENTS

%

40-49

23

24.40%

50-59

27

28.70%

60-69

15

16.00%

70-79

20

21.30%

>80

9

9.60%

TOTAL

94

100%

Fig-1: distribution of side of stroke among the patients

Table -2: Site of infarct among the patients according to their CT findings

CT FINDINGS

  1. OF PATIENTS

PERCENTAGE (%)

RT MCA INFARCT

16

17

LT MCA INFARCT

8

9

RT ACA INFARCT

2

2

ACA MCA WATERSHED INFARCT

3

3

LEFT FRONTAL LOBE INFARCT

2

2

LACUNAR INFARCTS

31

33

CEREBRAL ATROPHY

5

5

RT CEREBELLAR INFARCT

2

2

NORMAL STUDY

25

27

TOTAL

94

100

Fig -2: Association of risk factors & vessel stenosis among the patients.

Table-3: Distribution of plaque in the carotid system of the patients

SIDE OF PLAQUE

  1. OF PATIENTS

PERCENTAGE (%)

RT

28

47%

LT

24

41%

B/L

7

12%

TOTAL

59

100%

Fig -3: Plaque distribution according to site





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