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  • 1574

    Doppler Color Flow Imagingof Carotid Body Tumors

    W. Steinke, MD, M. Hennerici, MD, and A. Aulich, MD

    Doppler color flow imaging is a new ultrasound method for the simultaneous spatial display oftissue and vessel morphology (B-mode echotomograms) and of color-coded blood flow velocityinformation (Doppler-mode analysis). This new method is particularly useful in the neck, notonly for the assessment of brain arteries but also for the safe and valid identification of carotidparagangliomas compared with other neck tumors. Early clinical detection of carotid paragan-gliomas is difficult since these lesions often occur sporadically and the patients remainsymptom-free until the tumor becomes noticeable. Doppler color flow imaging allows thediagnosis of even small paragangliomas, which may improve management because of existingcomplications of surgical therapy. {Stroke 1989;20:1574-1577)

    Although carotid body tumors are thought to bethe most common type of paragangliomas,1- their prevalence and natural history areunknown because of the difficulties of early diagnosisand noninvasive follow-up. Meyer et al1 recentlyreviewed more than 600 cases reported in the litera-ture. Sporadic forms of carotid body tumors are morefrequent than autosomal dominant ones, which maypresent with a 32% incidence of bilateral tumors.Concepts for treatment of carotid body tumors areimpeded by the generally limited number of patientsreported in individual series. However, in a 50-yearretrospective study of 153 tumors from the MayoClinic, Hallett et al2 confirmed a persistent 40% risk ofcranial nerve lesions after surgery even if modernsurgical techniques were used. This high risk is sizedependent; the larger the tumor, the higher the post-operative complication rate.

    Although examination of the unaffected membersof a family with a known history of carotid bodytumors may result in the early diagnosis of smalltumors, early diagnosis is unlikely for the majorityof patients who present sporadically with or withoutminor complaints (e.g., discomfort, dysphagia,hoarseness, stridor) only after discovering a largepalpable mass in the neck.

    Noninvasive methods, and ultrasound in partic-ular, have only occasionally been used to assesscarotid body tumors.3-6 Hemodynamic Doppler-

    From the Neurologische Klinik der Universitat Diisseldorf,Diisseldorf, Federal Republic of Germany.

    Supported by the Deutsche Forschungsgemeinschaft GrantSFB 200/D2.

    Address for correspondence: Dr. M. Hennerici, Neurologi-sche Klinik der Universitat Dusseldorf, MoorenstraBe 5, D-4000Diisseldorf, Federal Republic of Germany.

    Received February 6, 1989; accepted June 23, 1989.

    mode analysis and B-mode echotomograms, eitheralone or combined in conventional duplex sys-tems, have often failed to definitely differentiatesuch lesions from other neck masses.5-6 The devel-opment of the Doppler color flow imaging (DCFI)technique facilitates the detection of blood flowin small tumor vessels, even in the absence ofsonographically identifiable wall structures, andtherefore may increase the diagnosis of carotidbody tumors at a very early stage. We present thecharacteristic features of DCFI in two patientswith carotid body tumors confirmed by subse-quent arteriography.

    Case ReportsDCFI examination was performed on an angio-

    dynograph (HQAD PV, Philips Medical System,Hamburg, FRG). The system uses a 7.5-MHz lineartransducer for the simultaneous display of a gray-scale (B-mode) tissue echotomograph and the Dopp-ler information, which is color-coded with regard tothe intravascular blood flow direction. Cell motiontoward the transducer is coded red, motion awayfrom the transducer is coded blue. Color saturationindicates signal amplitude, depending on the veloc-ity of the moving targets. In addition, a high-resolution conventional duplex scanner (DRF 400,Diasonics, Milpitas, California), combining a 4.5-MHz single-gate pulsed Doppler system with a10-MHz B-mode system, was used. The examina-tion procedure and results from normal subjects arereported elsewhere.7-8 Both patients underwent sub-sequent selected intra-arterial digital subtractionangiography (DSA).

    Case 1A 38-year-old man was admitted with familial

    hypercholesterolemia and coronary heart disease.

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  • Steinke et al DCFI of Carotid Paragangliomas 1575

    FIGURE 1. Case 1: a: High-resolution B-mode echotomo-gram of right carotid bifurca-tion. Widened angle ofbifurcation (BIF) with hetero-geneous echo-poor tissuebetween internal (ICA) andexternal (ECA) carotid arter-ies, b: Doppler color flowimage of right carotid bodytumor in corresponding longi-tudinal section of carotid bifur-cation. Hypervascularity be-tween ICA and ECA. c: Intra-arterial digital subtractionangiogram. Typical configura-tion of bifurcation, with smallvascularized tumor between twocarotid branches, with bloodsupply from ECA.

    His major complaint was exercise-dependent dys-pnea. For 2 years he had noted a small mass, whichhad increased in size without any associated symp-toms, in his right neck. Results of physical andneurologic examinations, including examination ofthe cranial nerves, were normal.

    High-resolution B-mode analysis showed a1.5x3.2 cm heterogeneous mass of poor echogenic-ity widening the right carotid bifurcation (Figurela). Irregularly distributed, bidirectional Dopplersignals in this area between the branching external(ECA) and internal (ICA) carotid arteries as revealedby DCFI supported the diagnosis of a hypervascu-larized tumor (Figure lb). Location and configura-tion of the carotid bifurcation and the state ofvascularization were considered typical for a carotidbody tumor. Intra-arterial DSA (Figure lc) con-firmed the diagnosis. Thoracic and abdominal com-puted tomograms gave no evidence of other paragan-gliomas. Concentrations of catecholamine metabolitesin the blood and urine were normal.

    This tumor was surgically removed without com-plications, and the diagnosis was histopathologi-cally confirmed.

    Case 2A 69-year-old woman was admitted for the diag-

    nosis of a pulsating mass at the left side of her neckbelow the mandibula; the mass had slowly increasedin size over 3 years and was initially considered tobe a carotid aneurysm. Results of physical andneurologic examinations were normal except for amoderate arterial hypertension and minimal pos-tural tremor. Results of routine laboratory investi-gations and concentrations of thyroid hormones andtumor markers were all within normal limits.

    High-resolution B-mode analysis demonstrated a2.6x2.8 cm circumscribed heterogeneous echo-poor tumor at the left carotid bifurcation stretchingthe ICA (Figure 2a). The ECA could hardly be seen,and the typical configuration of a widened carotidbifurcation was missed. However, DCFI showed a

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  • 1576 Stroke Vol 20, No 11, November 1989

    FIGURE 2. Case 2. a: Duplex sono-gram of left carotid bifurcationshowing circumscribed hypodensetumor stretching internal carotidartery (ICA). b: Doppler color flowimage of left carotid body tumorbelow ICA, with pathologic vascular-ity. c and d: Intra-arterial digitalsubtraction angiograms of left carotidartery, lateral (c) and anteroposte-rior views (d). Hypervascular tumorin area of bifurcation, stretching bothcarotid artery branches.

    diffuse vascularity near the carotid bifurcation (Fig-ure 2b). Intra-arterial DSA confirmed the diagnosisand demonstrated blood supply from branches ofthe ECA (Figure 2, c and d.)

    The patient refused surgical treatment.

    DiscussionDCFI is a recently developed ultrasound tech-

    nique. In addition to conventional duplex-systemanalysis, DCFI provides a simultaneous spatial dis-play from the Doppler shift data of blood flow invessels and organs, which is superimposed on theB-mode image. DCFI is particularly useful for thedisplay of small-caliber vessels, including tumorvessels, which are regularly missed during conven-tional duplex-system examination because of wallstructure interference.

    These case reports show the impressive appear-ance of carotid body tumors on DCFI. Diagnosis isbased on the widened contour of the bifurcation andon the easily recognized hypervascularity of thetumor. The latter is particularly necessary to differ-

    entiate tumors of the carotid body from avascular orhypovascularized cervical masses (e.g., lymph nodemetastases, salivary gland tumors, or brachialcysts).6 Thyroid tumors, which in some cases arehypervascular, are usually located medial to thecarotid bifurcation and differ from carotid bodytumors in their low peripheral resistance Dopplerprofile. Previous attempts to diagnose carotid bodytumors noninvasively by ultrasound are consistentwith our experience, indicating that it is not possi-ble to differentiate reliably between solid and cysticneck masses, which may both consist of heteroge-neous echo signals.5 Even if single-gate pulsed-wave Dopplersonography is added and an abnormalblood flow spectrum is assessed in selected areas,the lack of a two-dimensional blood flow display mayresult in considerable difficulty in combining ana-tomic and hemodynamic information.6 Thus, althoughit is often possible with conventional duplex ultra-sound to differentiate carotid aneurysms from tortu-ous vessels, demonstration of sonolucent areas in theabsence of flow signals by means of DCFI suggests

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  • Steinke et al DCFI of Carotid Paragangliomas 1577

    thrombotic material in an aneurysm and henceimproves the