Journal of Neurology, Neurosurgery, and Psychiatry 1990;53:379-383

Dissection of the cervical internal carotid artery.The role of Doppler/Duplex studies andconservative management

M S M Eljamel, P R D Humphrey,MD M Shaw

AbstractCervical internal carotid dissection is notrare. Doppler ultrasound screening ofyoung patients presenting with stroke,identified 10 patients with reduced com-mon and internal carotid blood flow with-out any evidence of atheroma. Eight, onangiography proved to have a dissectionofthe cervical internal carotid artery. Allwere managed conservatively. Sevenreceived anticoagulant therapy, stoppingany further neurological symptoms.

Mersey RegionalDepartment ofMedical and SurgicalNeurology, WaltonHospital, LiverpoolM S M EljamelP R D HumphreyMD M ShawCorrespondence to:Dr M S M Eljamel,The Mersey RegionalDepartment of Medical andSurgical Neurology, WaltonHospital, Rice Lane,Liverpool L9 1AE.Received 3 January 1989and in final revised form 28September 1989.Accepted 1 November 1989

Since Jentzer' reported a case of a spon-taneously dissecting aneurysm of the internalcarotid artery in 1954, an increasingly largenumber of reports have found a higherincidence than had initially been thought.2'Spontaneous resolution, with a good recovery,has been documented.'3 This report examinesthe screening of young patients, with stroke ortransient ischaemic attacks (TIAs), using Dop-pler ultrasonography to decide which patientsshould undergo angiography to detect internalcarotid artery dissection; the results of nonsurgical management of this condition are alsogiven.

PatientsEight patients, in whom dissection of thecervical internal carotid artery was diagnosedon angiography, were admitted to the regionalunit from a population of approximately threemillion, during the period September 1986 toMay 1988. During this time 700 Doppler/

Duplex examinations were carried out for vas-cular disease.The details of the clinical presentations are

summarised in table 1. The male:female ratiowas 5:3 and the age range 14 to 55 years.Cerebral hemisphere signs were present in allcases. Transient ischaemic attacks occurred inthree cases, stuttering stroke (that is, a strokeevolving in a stepwise fashion) in a furtherthree cases, and multiple strokes in the othertwo patients. One patient began with transientischaemic attacks and subsequently developeda stuttering stroke (case 8). Of the multiplestrokes, one (case 6) had a left hemispherestroke four years earlier and had undergone anextracranial-intracranial bypass procedure,elsewhere, on the right side in addition to beinggiven antiplatelet agents, and the second case(case 7) experienced progressive visual failureover three years from multiple cerebral in-farcts. In only one case was a carotid bruitfound on examination.More than half the patients were or had been

smokers. Using the definitions accepted in theFramingham Study,9 four patients were hyper-tensive, three falling into the definite and oneinto the borderline categories. Two patients(cases 1 and 7) had family histories of vasculardisease. Two had experienced recent minortrauma to the neck: case 2 as the result of a kickto the opposite side of the neck during martialarts training and case 4 rotational effects afterbeing struck on the nose by a falling object.Case 8 had sustained a moderately severe headinjury 20 years earlier.

Table 1 Clinical details

Case no Patient Clinicalfeatures Event Factors

1 14 M headache stutteringL umn paresis stroke 10 days

2 17 M headache stuttering smokerR umn paresis stroke 10 days neck traumadysphasia

3 37 F R umn paresis stuttering BP 170/90dysphasia stroke 14 days oral

contraceptive4 37 F headache 5 TIAs BP 160/90

R umn paresis (45 min each) smokerparaesthesia R arm 7 days nasal traumadysphasia

5 38 M paraesthesia R face 2 TIAs smokeramaurosis fugax 2 weekscarotid bruit

6 40 M R hemiparesis 2 strokes smokerdysphasia 4 yrs & now

7 47 F slow visual loss strokes + + + BP 180/120paraesthesia L arm over 3 yrsdysphasia

8 55 M R uimn paresis TIAs 18 mths BP 150/90paraesthesia R arm then progressive ex-smoker

stroke 3 mths

InvestigationsComputerised tomography (CT) scans con-firmed the presence of infarcts in 75% of cases.The majority were in the cortex and thesubcortical white matter but in case 1 wererestricted to the capsule and the caudatenucleus (fig 1).Duplex ultrasonic and CW Doppler exami-

nations (using a Diasonics Duplex CV 400scanner and a Kranzbuhler 761 CW flowmeter)were used as screening tests in all cases.Reduced flow in both the common and internalcarotid arteries, upon the side appropriate tothe clinical features was found in all cases (fig2). Atheroma was detected in 3 cases, 2 ofwhom had bilateral disease. However in noneof these three was the atheroma severe enoughto account for the reduced flows in the commonand internal carotid arteries. Reversal of flowthrough the supraorbital vessels occurred in

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Figure I Caudatenucleus infarct on CT(arrow indicates).

only one case. The dissection itself was seen onDuplex scanning (fig 3) in two cases. Fivepatients had Duplex Scanning within twoweeks of onset of symptoms; two within threemonths of the last symptom and one at a year.

Cerebral digital subtraction angiographywas carried out by intra-arterial injection in allcases (table 2). Each case showed the "stringsign", (fig 4a) which is considered to be diag-nostic for the condition, in the cervical internalcarotid artery. The lesion was left sided in five,right sided in two and bilateral in one.

Figure 2 Dopplervelocity in internal carotidartery a) normal,b) reduced.

The other angiographic findings were:1) Embolic occlusion of one or more of thedistal intracranial arteries in four patients;2) "beading" of the contralateral internalcarotid artery compatible with fibromusculardysplasia was present in two patients; 3) ananeurysm arising from the cervical portion ofthe internal carotid artery, adjacent to the skullbase in one patient (fig 4a and b) mild atheromawas demonstrated in only two patients, both ofwhom had bilateral disease demonstrated onultrasonic examination.Two additional young patients, aged nine

and 22, who had reduced internal carotid flowon Doppler studies, and no other abnormalityin the cervical carotid arteries even onangiography, had multiple intracranial vas-cular occlusions of the distal branches of themiddle and anterior cerebral arteries. These,therefore represent false positives.One patient, aged 43, had a left hemiplegia

and right Horner's sign with reduced rightinternal carotid artery flow. Angiography wasnot thought justifiable as his deficit wascomplete.

ManagementAnticoagulation, using heparin initially andwarfarin for twelve months, was started withinthree weeks of the ictus in four patients, threeof whom presented with stuttering strokes.The outcome in each was good (table 3), eventhough two had further minor attacks beforefull anticoagulation was achieved. Three of thefour patients who were initially treated withantiplatelet agents (aspirin in all cases pluspersantin in cases 5 and 6) continued to haveattacks and were therefore switched toanticoagulants, with symptomatic control.Case 6 had had a right sided extra/intracranialbypass operation carried out following the firststroke (which affected the left cerebral hemis-phere) suffered four years before presentationto this unit.

Repeat Doppler studies after anticoagulanttreatment was instituted showed an improvedflow in four cases, three of whom had beenanticoagulated within three weeks of the ictus.

DiscussionCervical internal carotid dissection is a more

Figure 3 Fixed linear shape (arrow indicates) in lumenof internal carotid artery above bifurcation thought to besecondary to dissection.

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381Dissection of the cervical internal carotid artery

Table 2 Investigations

Case no Side CT infarct Doppler* Angio (int carotid)

1 R capsule/caudate flow reduced "string" signdysplasia**distal occl'

2 L cortex flow reduced "string" signwhite matter distal occl"

3 L cortex flow reduced "string" sign4 L - atheroma/flow "string" sign

reduced5 R - flow reduced/ "string" sign

reversed supra-orbital flow distal occlnec aneurysm

6 R and L old cortex/ L flow reduced "string" signwhite matter mild stenosis

7 L multiple cortex/ flow reduced "string" signwhite matter bilat atheroma dysplasia**

distal occlbilat atheroma

8 L multiple cortex/ flow reduced "string" signwhite matter bilat atheroma bilat atheroma

*Reduced flow was found in the appropriate internal and common carotid arteries.**Fibromuscular dysplasiaec-extracranial

common cause of cerebral ischaemia than hasbeen previously recognised.25 Its pathogenesisis not fully understood, but some conditions,which are associated, may be causal agents;these include fibromuscular dysplasia of theinternal carotid and the renal arteries which hasbeen reported in 10-20% of cases,2 31014 cysticmedial necrosis,415 hypertension, atheroma, afamily history of arteriosclerosis, and phaeo-chromocytoma.'6 Two of this current seriesshowed angiographic appearances compatible

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with the diagnosis of fibromuscular dysplasia,four were hypertensive (including one patientwho was borderline as judged by the Fram-ingham criteria),9 two had atheromatous dis-ease seen on angiography and two a familyhistory of arterial disease. Spontaneous inter-nal carotid artery dissection is well recognised.The significance of the patients with minortrauma remains uncertain as there has been nocase control study to our knowledge. Mostcentres in the United Kingdom do not performangiograms on all young patients with TIAs orstroke; however a history of recent trauma mayinfluence this decision creating a biasedimpression that dissection usually followstrauma. This study used Doppler/Duplexscanning as the discriminator and a history ofminor trauma was elicited in two of the eightpatients. Minor trauma in the form of either, aminor direct blunt injury to the neck, orrotation (particularly if combined with anelement of flexion/extension) of the neck, can-not be excluded as an initiating factor."7-9 Incentres where all young stroke patients havehad angiograms, cervical carotid dissection isthe dominant cause.20Three patients had ipsilateral headache at

presentation as described previously.2' Theliterature suggests that carotid bruits are foundat the time of presentation in 10-50% of caseswhilst occulosympathetic paresis (Horner's

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Figure 4 Angiogram a: string sign, b) aneurysm (A). CCA-common carotid artery, ICA-internal carotid artery, ECA-external carotidartery.

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Table 3 Treatment andfollow up

Case Therapy Time Ictusl Doppler Flow Follow up afterNo Anti-Coag/Platelet Therapy Change Outcome this therapy

1 + - 13 days improved good 14 mths2 + - 10 days improved good 31 mths3 + - 20 days none good 16 mths4 + - 1 day improved good 15 mths5 - + 0 days improved good 22 mths6 + + 4 mths none old R hemiparesis 12 mths7 + + 24 mths none poor vision 14 mths8 + + 2 mths improved good 14 mths

Cases 6, 7, and 8 all had further ischaemic events on aspirin and were therefore anticoagulated.Good outcome = full functional recovery and no further ischaemic events following establishment of therapy.Cases 6 and 7 continued with their pre-anticoagulation deficit.

syndrome) which is thought to be one of thecardinal signs, is present in 21-58%. Both mayspontaneously resolve in the first week.3 1013 14Carotid bruits were heard in one case but noangiographically proven case demonstrated an

occulosympathetic paresis.The Doppler/Duplex examination is a sim-

ple non invasive test, carrying little risk and inexperienced hands is a reliable method ofscreening patients presenting with carotiddisease.22 Eight cases of angiographicallyproven dissection of the cervical internalcarotid artery have been discovered in youngpatients having strokes.Doppler/Duplex examinations were carried

out in all eight cases on presentation beforeangiography, and showed that the blood flow inthe common and proximal internal carotidarteries was considerably reduced. However,the reduction in flow as judged on Dopplerstudies is a non specific finding. In the absenceof a significant stenosis at the bifurcation, itimplies that there is a distal obstruction to flow,either in the distal cervical internal carotidartery or in the intracranial run off from theinternal carotid artery. In this unit this dopplerfinding has usually been due to dissection,there being only two other young patients withsuch reduced flow who did not have a dissec-tion; in both cases angiography showed this wasdue to intracranial multi-vessel occlusion.These cases could therefore be considered as

false positives. Doppler will only detect a

proximal flow change from a dissection if thelumen of the internal carotid artery is reducedby 60% or more; this criterion is likely to befulfilled if the "string sign" is present. Imagingthe vessel may help in some of these cases withless severe degrees of stenosis; in two cases itshowed a consistent intravascular echo in theinternal carotid artery just distal to the bifurca-tion (fig 3). This was thought to be the dissec-tion. Similar findings have been reported invertebral artery dissection.23Doppler was also used as an objective follow

up test to monitor progress. An increase in flowwas found in the majority of patients whoimproved (table 3).Angiography, which carries a recognised

mortality and morbidity,24 is often unreward-ing in the young when investigating ischaemicdisease. We believe it is not justified to carryout angiography in all young patients with TIAor stroke not attributable to subarachnoidhaemorrhage. Nor do we usually angiogrampatients with a dense stroke; there was one

other young patient with a left hemiplegia andright Horner's syndrome with reduced flow inthe right carotid artery in whom angiographywas not performed, because his deficit wascomplete. It is therefore not possible todetermine a false negative rate for Doppler/Duplex scanning in carotid dissection. All thecases reported here had TIAs or a partialdeficit; angiography was performed on thebasis of the Doppler/duplex findings before adecision about anticoagulation. Each showedthe "string sign" and half, distal occlusion. Thefrequency of the "string sign" was similar topreviously reported series but distal occlusionseems to be two and five times more common inthis group.2' 10 113 14Management of internal carotid dissection

remains controversial and varies from in-activity3410 to surgical intervention.241011 1425 26

Antiplatelet agents have been advocated,particularly in those presenting with unilateralheadache, bruits or occulosympathetic pare-sis.310 Other authors5610 1327-29 have reportedthe use of anticoagulant therapy both withheparin and with warfarin. Though the risk ofhaemorrhage into infarcted areas of brain iswell recognised, it has not proved a problem inthe treatment of spontaneous dissection of the

3 5 6 10 13 27-9cervical internal carotid artery.Antiplatelet agents did not stop the symptomsin three of the four patients in this study. Anti-coagulation on the other hand stopped theprogression of symptoms in the patients withstuttering strokes or transient ischaemic attacksand in those who continued to have symptomsin spite of treatment with aspirin. Though thefollow up is as yet short, complete resolution ofneurological symptoms has occurred in thethree patients presenting with stutteringstroke. Late transient neurological events havebeen described in the Bordeaux study quotedby Bogousslavsky,30 although recurrent dissec-tion is very rare.13 19

Operation is made difficult by the extensionof the dissection to the skull base. However inspite of the morbidity and mortality, surgerycan be considered in refractory cases not res-ponding to medical management, provided thatthe dissection is accessible. Extra-intracranialbypass surgery has been advocated in cases inwhich distal occlusion has occurred.310

In conclusion, dissection of the cervicalinternal carotid artery has proved to be acommon cause of stroke or transient ischaemicattack in the young patient presenting to thisunit. More minor cases may well go undetec-

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Dissection of the cervical internal carotid artery

ted. Doppler/Duplex ultrasonography wouldseem to be a useful screening test and helpsmake the decision as to whether one shouldproceed to angiography in this young agegroup. Anticoagulation would seem to be thetreatment of choice in those with recurrent orprogressive hemisphere neurological symp-toms and signs whose deficit is not complete.

We are grateful to the Medical Research Council,The Chest, Heart and Stroke Association, and theMerseyside Research Association for financial help.

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