Duplex carotid sonography: criteria for stenosis, accuracy, and pitfalls.

Jacobs, Norman; Grant, E G; Schellinger, Dieter; Byrd, Marcus; Richardson, J. David; Cohan, Stanley

doi:10.1148/radiology.154.2.3880910

Cited by 113 publications

(20 citation statements)

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“…Direct Vélocimétrie Criteria These criteria, validated by numerous authors, use maximum systolic and maximum end-diastolic frequencies/velocities obtained by continuous-wave (CWD) (ta ble 1) [11][12][13][14][15][16][17][18] and pulsed-wave Doppler (PWD) (table 2) [19][20][21][22][23][24][25][26][27][28][29]; these values are inversely proportional to the degree of stenosis in area.…”

Section: Ultrasoundmentioning

confidence: 99%

Quantification of Atheromatous Stenosis in the Extracranial Internal Carotid Artery

Bray¹,

Glatt²

1995

Cerebrovasc Dis

197

125

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An international consensus meeting to determine criteria for the quantification of stenosis of the extracranial internal carotid artery was held in Paris on December 2 and 3, 1994. A review of the literature and expert analysis of validity and reproducibility led to the following recommendations: Intra-arterial X-ray angiography: At present, two main methods of quantification are being evaluated, the distal and the local method, the former being the better validated. The latter method, on the other hand, is better able to represent moderate lesions at the level of the carotid bulb. Therefore, it is suggested that a ratio between the stenosis and the common carotid artery should also be established. X-ray angiography prior to carotid endarterectomy can be avoided if ultrasound and MR angiography concur in identifying severe stenosis provided that intracranial vessels are without relevant disease. Ultrasound Doppler duplex methods can quantify the degree of extracranial carotid artery stenosis in terms of both diameter reduction according to the criteria established by recent surgical studies (NASCET – distal degree of stenosis – and ECST – local degree of stenosis – as well as residual area in cross-sections. The latter is more suitable since hemodynamic effect, local increase of velocity, and pressure drop are taken into consideration. Technical requirements (carrier frequency 4–5 MHz, Doppler angle inferior to 60°, sample volume ≧5 mm) call for a combination of three validated criteria. Maximum Doppler shift/flow velocities measured at the narrowest point of the stenosis and the degree of poststenotic flow disturbances should be examined. In systole, a value of 4 kHz (120 cm/s) (f0 = 4 MHz), identifies most stenoses >50% in local diameter reduction and as in end-diastole, a value of 4.5 kHz (135 cm/s) identifies stenoses of >80%. Carotid ratio: The systolic velocity ratio should be recorded between the site of the stenosis and the common carotid artery obtained 3 cm below the bifurcation. This limits the influence of general hemodynamic factors unrelated to the stenosis such as the cardiac output. A threshold value of >1.5 determines stenoses of >50% and a threshold value of >4, stenoses of >70%. Area ratio: The ratio between the total arterial lumen in cross-section and the minimal residual lumen should be determined by echotomography and additional color Doppler flow imaging. In addition there are indirect criteria, such as asymmetry of pulsatility of the common carotid artery and middle cerebral artery signals as well as inverted flow of the ophthalmic artery which distinguish moderate from high-degree stenoses (>80% diameter reduction). Magnetic resonance angiography (MRA): With this method, a diameter ratio using the distal degree of stenosis is recommended with data obtained from transverse source images in addition to transverse T1 sequences. MRA is a complement to ultrasonic methods, particularly in cases of calcified stenoses and for the analysis of intracranial vessels.

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Section: Ultrasoundmentioning

confidence: 99%

Quantification of Atheromatous Stenosis in the Extracranial Internal Carotid Artery

Bray¹,

Glatt²

1995

Cerebrovasc Dis

197

125

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“…External carotid artery (ECA) stenosis is less frequent and clinically less important than ICA stenosis, but it may be the cause of carotid bruit if there is no stenosis in the ICA. The duplex US findings concerning external carotid stenosis have been handled in the same material with internal carotid stenoses (6,8,12,16), and the same Doppler criteria have been used to evaluate them. However, the flow values seem to be different in the ECA, and we wanted to establish the velocity criteria.…”

mentioning

confidence: 99%

Duplex US of the External Carotid Artery

et al. 1996

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The ratio between the systolic peak velocities of the internal and common carotid arteries (vpICA/vpCCA), vpICA and grey-scale imaging measurement are generally used to evaluate internal carotid stenosis against known flow criteria in order to differentiate non-significant from significant stenosis. The same criteria are also used for evaluating the external carotid artery (ECA). Our data on 707 normal or stenotic ECA nevertheless showed that the systolic peak velocity of the normal ECA (vpECA) and its ratio to the systolic velocity of the CCA (vpECA/vpCCA) are higher than vpICA and vpICA/vpCCA. vpECA/vpCCA is about 2 in > 0-49% ECA stenosis. Only in severe stenosis are the peak velocities almost comparable. The ratio between the peak end diastolic velocities (edvECA/edvCCA) and edvECA proved to be unreliable, as did grey-scale imaging measurement of the external carotid stenosis. In addition, ipsi-lateral internal carotid stenosis greatly affects the non-stenotic external carotid flow values, and probably has the same effect on the flow values of a stenotic external artery. Thus, external carotid flow values must be considered carefully.

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“…B-mode imaging, however, also has major limitations [19], Fresh red thrombi, flowing blood, intraplaque hem orrhages, and even atheroma share low echogenity as a characteristic feature [20]. A minimum amount of early organization by connective tissue is necessary for very fresh thrombi to be differentiated by B-mode ultra sound.…”

Section: Discussionmentioning

confidence: 99%

B-Mode Imaging of Intraluminal Thrombus of the Internal Carotid Artery

Weiller¹,

Reinartz²,

Füzesi³

et al. 1991

Cerebrovasc Dis

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Six patients with the diagnosis of intraluminal thrombus of the internal carotid artery are reported. In the first 2 patients with large thrombi, CW-Doppler sonography, B-mode scanning, and histological findings were in agreement The third patient had CW-Doppler and B-mode sonographical findings of a large intraluminal thrombus immediately before an embolic cerebral infarct. Three weeks later, angiography showed a plaque with only an excavation remaining. Another patient had an intraluminal thrombus superimposed on a nonstenosing plaque which was not detected by CW-Doppler sonography but could be identified during B-mode scanning. Angiography and pathoanatomy were confirmative. The fifth patient with B-mode visualization of an echolucent intraluminal structure did not show any thrombus intraoperatively. The sixth patient is reported to demonstrate the failure of B-mode imaging as well as angiography in detecting clots which were found pathoanatomically. Intraluminal thrombi as potential sources of brain embolism can be attached to atherosclerotic plaques of any degree of stenosis. Nonstenosing lesions with an attached thrombus may escape CW-Doppler sonography and even angiography but may be shown during high-resolution B-mode imaging. False-positive findings, however, cannot be avoided. Plaques with thrombi may cause strokes more frequently than assumed.

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Duplex carotid sonography: criteria for stenosis, accuracy, and pitfalls.

Cited by 113 publications

References 0 publications

Quantification of Atheromatous Stenosis in the Extracranial Internal Carotid Artery

Quantification of Atheromatous Stenosis in the Extracranial Internal Carotid Artery

Duplex US of the External Carotid Artery

B-Mode Imaging of Intraluminal Thrombus of the Internal Carotid Artery

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