Diagnostic reliability of the percutaneous ultrasonic Doppler technique for vertebral arterial occlusive diseases

Ultrasound Criteria for Assessment of Vertebral Artery Origins

BACKGROUND AND PURPOSE

We sought to validate ultrasound as a reliable means of assessing vessel stenosis of vertebral artery origins.

METHODS

We reviewed 1,135 patient charts with ultrasound of the posterior circulation performed in 2008-2015 in a single hospital. Inclusion criteria for native vessels consisted of ultrasound and digital subtraction angiography (DSA) performed within 3 months. Patients with indwelling stents were analyzed separately from native vessels. Using DSA as the gold standard, we determined sensitivity and specificity of ultrasound in detecting occlusion at vertebral artery origin. All patients with nonoccluded native vertebral artery origins were evaluated for degree of stenosis on DSA, and compared to mean flow velocity (MFV), peak systolic velocity (PSV), and end-diastolic velocity (EDV) on ultrasound.

RESULTS

Among 218 vertebral artery origins in 139 patients evaluated, ultrasound showed sensitivity of 85.7% (95% confidence interval (CI): 69.7-95.2%) for occlusion and specificity of 99.5% (95%CI: 96.9-99.9%). Among 126 arteries without occlusion, <50% stenosis had average MFV (39 ± 19 cm/s), 50-69% stenosis had average MFV (68 ± 35 cm/s), and severe (70-99%) stenosis had average MFV (120 ± 93 cm/s) (P < .001). MFV cutoff value of 44 cm/s corresponded to 77% sensitivity and 70% specificity to detect vertebral artery origin stenosis >50% (C-statistic: .81). PSV value of 97 cm/s corresponded with 72% sensitivity and 70% specificity to detect >50% stenosis (C-statistic: .77). MFV cutoff value of 60 cm/s corresponded with 70% sensitivity and 82% specificity to predict 70-99% stenosis (C-statistic: .83). PSV cutoff value of 110 cm/s corresponded with 80% sensitivity and 72% specificity to predict 70-99% stenosis (C-statistic: .84).

CONCLUSION

Ultrasound has good sensitivity and excellent specificity for detecting vertebral origin occlusion. Flow velocity can be used to screen for severe stenosis of vertebral artery at origin.

Reliability and validity of clinical tests to assess the anatomical integrity of the cervical spine in adults with neck pain and its associated disorders: Part 1-A systematic review from the Cervical Assessment and Diagnosis Research Evaluation (CADRE) Collaboration

OBJECTIVE

To determine the reliability and validity of clinical tests to assess the anatomical integrity of the cervical spine in adults with neck pain and its associated disorders.

METHODS

We updated the systematic review of the 2000-2010 Bone and Joint Decade Task Force on Neck Pain and its Associated Disorders. We also searched the literature to identify studies on the reliability and validity of Doppler velocimetry for the evaluation of cervical arteries. Two independent reviewers screened and critically appraised studies. We conducted a best evidence synthesis of low risk of bias studies and ranked the phases of investigations using the classification proposed by Sackett and Haynes.

RESULTS

We screened 9022 articles and critically appraised 8 studies; all 8 studies had low risk of bias (three reliability and five validity Phase II-III studies). Preliminary evidence suggests that the extension-rotation test may be reliable and has adequate validity to rule out pain arising from facet joints. The evidence suggests variable reliability and preliminary validity for the evaluation of cervical radiculopathy including neurological examination (manual motor testing, dermatomal sensory testing, deep tendon reflexes, and pathological reflex testing), Spurling's and the upper limb neurodynamic tests. No evidence was found for doppler velocimetry.

CONCLUSIONS

Little evidence exists to support the use of clinical tests to evaluate the anatomical integrity of the cervical spine in adults with neck pain and its associated disorders. We found preliminary evidence to support the use of the extension-rotation test, neurological examination, Spurling's and the upper limb neurodynamic tests.

Pre-manipulative testing and the use of the velocimeter

Manipulation of the cervical spine remains a common intervention for neck pain and dysfunction, despite the well-documented associated risk of vertebrobasilar stroke. The currently advocated pre-manipulative risk assessment protocols include the use of provocative positional tests to challenge the integrity of the vascular supply to the brain. This paper critically evaluates the validity of these pre-manipulative provocative tests in the light of ultrasonographic blood flow studies of the vertebral arteries. It also critically evaluates the evidence concerning the clinical utility of a portable continuous wave Doppler device (or velocimeter) to examine vertebral artery blood flow prior to neck manipulation. There is clear evidence that the provocative tests may produce both false positive and false negative findings. Initial research regarding the clinical use of a velocimeter suggests this device may provide a more objective assessment of vertebral artery blood flow than the provocative tests. However, the sensitivity, specificity and reliability of the use of the velocimeter in identifying abnormal vascular flow in the vertebral arteries, and therefore its clinical utility, has not yet been fully established.

Posterior ponticles and rotational stenosis of vertebral arteries. A pilot study using Doppler ultrasound velocimetry and magnetic resonance angiography

OBJECTIVE

To determine whether the presence of posterior ponticles markedly increases by 30% or more, the incidence of major rotational stenosis of vertebral arteries.

METHODS

Doppler ultrasound studies were performed in 3 private chiropractic clinics and in the radiology department of a public hospital, and magnetic resonance angiography (MRA) studies were made in the latter location. Thirty-two chiropractic patients had Doppler velocimetery, and 16 of these patients had MRA scanning. The outcome measures included changes in Doppler velocimetry signals and MRA images indicative of marked rotational stenosis of vertebral arteries.

RESULTS

All vertebral arteries from the 32 patients displayed no signs indicative of marked rotational stenosis.

CONCLUSION

The findings of this study show that the incidence of major rotational stenosis of vertebral arteries is not markedly increased by the presence of posterior ponticles.

Echo-enhanced duplex sonography of extracranial vertebral arteries

We sought to investigate the potential benefit in examining extracranial vertebral arteries (ExVA) with an echo contrast agent. A total of 26 patients with insufficiently assessable ExVA underwent extracranial duplex sonography without and with an echo contrast medium. All examinations were recorded and analysed independently by two experienced sonographers. Interrater agreement was fair in assessment of B-mode quality, colour-coding, blooming artefacts, change of vmax, good to very good in all other rated categories. Using an echo contrast medium reduced overall inassessable ExVA by 48% and 36% according to the two raters, respectively. After contrast enhancement, diagnosis was clarified in ExVA formerly inassessable for hypoplasia in 60% vs. 56%, extracranial occlusion in 67% vs. 56% and resistance signal in 63% vs. 45%, respectively. Application of an echo contrast agent leads to clarification of ExVA sonographic diagnosis in approximately one third of poorly examinable patients (35% and 30%, respectively), and contributes in ruling out extracranial occlusion, hypoplasia and resistance signal.

Transesophageal echocardiographic identification of bilateral vertebral artery ostial stenosis

We describe the usefulness of transesophageal echocardiography in correctly diagnosing severe ostial stenosis of both the left and right vertebral arteries in an adult patient. Although transesophageal echocardiography has been previously used to identify left vertebral artery stenosis, to our knowledge this study represents the first demonstration of its usefulness in detecting bilateral vertebral artery ostial stenosis.

Vertebral arteries and cervical movement: Doppler ultrasound velocimetry for screening before manipulation

OBJECTIVE

It has been proposed that Doppler velocimetry, which is noninvasive, quick, and relatively inexpensive, should be used when the screening vertebral arteries before manipulation to reduce the risk of cervical manipulation-related injury to these vessels. The objective of this analysis of the literature is to study the evidence of the suitability of Doppler velocimetry for this purpose.

DATA SELECTION

Studies were examined that dealt with the incidence of stroke after manipulation, the proposed mechanisms for this clinical entity, the validity of the provocational tests that have been used in screening before manipulation, the validity and reliability of Doppler velocimetry of vertebral arteries, and the biomechanics of vertebral arteries.

RESULTS

There is a suspicion of increased risk for vertebrobasilar stroke for vertebral arteries that have markedly reduced patency in the neutral position and/or stenosis during cervical rotation. There is evidence that provocational tests lack validity and that Doppler velocimetry is valid in assessing the patency of vertebral arteries in the neutral position and during cervical rotation. Interexaminer reliability of the Doppler technique has been shown to be high. Doppler ultrasound screening also seems to be able to provide an indirect assessment of the mechanical stresses to the artery during cervical movements.

CONCLUSION

There is strong evidence to suggest that Doppler velocimetry should be included in the screening of vertebral arteries before manipulation.

Vertebral arteries and neck rotation: Doppler velocimeter interexaminer reliability

The purpose of this study was to test the interexaminer reliability of Doppler ultrasound (US) velocimeter examination of vertebral arteries during contralateral cervical rotation. Vertebral arteries from 20 adults were insonated using a bidirectional Doppler velocimeter at the suboccipital portal (standard technique) and C2 transverse process level (new technique) during contralateral cervical rotation. The data obtained by two examiners, regarding persistence or major reduction in Doppler signals, were compared. There was 93% agreement between the data from the two examiners, and the kappa score was 0.78 at p = 0.05. These results provide evidence to support the interexaminer reliability of bidirectional Doppler velocimeter examination for the purpose of assessing the effects of contralateral rotation on vertebral artery blood flow.

Vertebral arteries and neck rotation: Doppler velocimeter and duplex results compared

The purpose of this study was to test the validity of Doppler ultrasound (US) velocimeter examination of vertebral arteries during contralateral (to the opposite side) cervical rotation. Vertebral arteries from 20 subjects were insonated using a bidirectional Doppler velocimeter at the suboccipital portal (standard technique) and C2 transverse process level (new technique) during contralateral cervical rotation. The results, regarding persistence or major reduction in Doppler signals, were then compared with those from a colour-flow duplex US scanner using the same procedure. There was complete agreement between the combined suboccipital and C2 velocimeter results and those from the duplex scanner (k = 1.00 at p = 0.01): both sensitivity (n = 5) and specificity (n = 34) were 100%. This study provides evidence to support the validity of bidirectional Doppler velocimeter examination, by an experienced examiner, for the purpose of assessing the effects of contralateral rotation on vertebral artery blood flow.

The role of vertebral and internal carotid artery disease in the pathogenesis of vertebrobasilar transient ischemic attacks

Color-coded duplex sonography has improved the evaluation of the hemodynamics of the vertebral arteries (VA). A reliable differentiation between a normal vessel, hypoplasia, stenosis and occlusion of VA can now be made. We studied two groups of patients in a prospective study with isolated carotid artery disease (n = 48), and with a combination of carotid and vertebral artery disease (n = 14), to determine the role of VA in the pathogenesis of transient ischemic attacks (TIAs) in the vertebrobasilar system. Apart from the existing arteriosclerotic changes of the internal carotid arteries, the condition of the VA was of importance for the occurrence of TIAs in the vertebrobasilar territory. We found that 8% of the patients with isolated hemodynamically relevant stenosis or occlusion of one or both internal carotid arteries had a TIA in the vertebrobasilar territory. Patients with combined carotid and vertebral artery disease had an increase of TIAs in the same region in 71%. The high rate of TIAs in this group might be attributed to the combined effect of carotid and vertebral artery disease, as a third group (n = 30) with isolated vertebral artery disease showed TIAs in only 13%.

Duplex ultrasonography of vertebral arteries: examination, technique, normal values, and clinical applications

A technique for the imaging of vertebral arteries at their origins and along the longitudinal extracranial course is described. The results of the examination of 108 normal vertebral arteries are shown. The vertebral artery could be distinguished in the pretransverse and intertransverse segment C5-C6 in 100%. The average diameter of the vessel was 3.81 +/- 0.46 mm on the right and 3.88 +/- 0.47 on the left side. The average maximal systolic velocity was 43.0 +/- 8.9 cm/s on the right and 43.3 +/- 9.6 on the left side. In 81% of the cases the vertebral origin could be located on the right and in 65% of the cases on the left side. The technical quality of visualization, especially of the vertebral origin, was greatly influenced by the depth of the examined structure. Examples of pathologic findings, such as hypoplasia, stenosis, and occlusion, demonstrate the practical possibilities of this noninvasive method.

Continuous-wave Doppler of vertebral arteries in noninvasive diagnosis and management of vertebro-basilar TIAs

Continuous-wave Doppler and angiography of the vertebro-basilar system were used in 38 patients with vertebro-basilar transient ischemic attacks. 63 vertebral arteries were studied. Among 47 normal Doppler parameters, 46 were confirmed by angiography. The sonographic diagnostic procedure showed a very high negative predictive value (97.87%), while the positive predictive value was relatively low (56.25%). Data from literature were reviewed. The authors suggest that when Doppler of vertebral arteries is negative, there is a very low probability that a follow-up angiography will reveal pathologic conditions calling for a surgical approach.

Vertebral artery Doppler sonography

We have examined the vertebral and subclavian arteries in 1,205 patients using directional continuous-wave (c-w) Doppler sonography, and compared the sonographic findings with the results of unilateral or bilateral retrograde brachial arteriographies in the same patients. Doppler sonography revealed 33 false positives among 909 cases with normal angiographic findings. Some types of vertebral artery (VA) lesions allowed an excellent, others a fairly good differentiation by Doppler sonography: the complete subclavian steal syndrome with constant reversal of VA flow was reliably detected (16 cases). In the incomplete steal syndrome (5 cases) sonography was superior to angiography. Two bilateral distal VA occlusions and seven basilar artery occlusions - six in the proximal third and one in the rostral third - were detected sonographically; four basilar occlusions sparing the caudal third and one case exhibiting rete mirabile anastomoses were not identified by Doppler sonography. Our acoustically defined sonographic criteria did not permit an unequivocal assignment to an anatomical variant or a vascular lesion. The sensitivity in the detection of a severe stenosis at the VA origin amounted to 16 out of 31, and to 12 of 25 in cases with a proximal VA occlusion and reconstitution of the distal VA through cervical collaterals. Our results confirm that the conventional hand-held c-w Doppler sonography cannot replace angiography in the evaluation of vertebro-basilar insufficiency. It rather serves as an aid to the decision for or against angiography, and in the follow-up of angiographically proven lesions. However, several therapeutically important lesions are readily diagnosed by sonography.

Validity of continuous-wave Doppler sonography of the vertebrobasilar system

To assess the value of continuous-wave Doppler sonography for detection and exclusion of lesions in the vertebrobasilar system, the ultrasonic and angiographic findings were compared in a prospective study. Altogether, 200 vertebral arteries in 176 patients were evaluated by both methods. Insonation of the vertebral arteries was performed at the mastoid slope and at the origin of the vessel. Of 62 angiographically proven lesions, 45 were detected by ultrasound. Of 138 normal vertebral arteries, 129 were correctly diagnosed. Sensitivity for all lesions was 72.5%, and for hemodynamically relevant lesions it was 91%. Overall specificity was 93.5%. A positive predictive value of 83.3% and a negative predictive value of 88.4% for all lesions shown by angiography demonstrate the high reliability and accuracy of doppler ultrasound of the vertebrobasilar system.

The role of continuous-wave Doppler sonography in the diagnosis and management of basilar and vertebral artery occlusions, with special reference to its application during local fibrinolysis ("Vertebrobasilar disease. Time for a new strategy." Louis R. Caplan, 1981)

In general, the prognosis of bilateral vertebral or basilar artery occlusions is very poor. No satisfactory management of this condition is known; in addition, the early diagnosis of severe lesions of the "intradural vertebrobasilar artery" on the basis of clinical signs and symptoms alone is difficult and regularly requires invasive procedures. Continuous-wave Doppler sonography has proved to be of great value in the primary diagnosis of vertebrobasilar thrombosis. In two cases, in whom bilateral intracranial vertebral artery lesions and basilar thrombosis were successfully treated with the help of local intraarterial fibrinolysis, Doppler sonography proved to be a reliable diagnostic tool for the evaluation and the non-invasive follow-up of thrombolysis. Clinical, Doppler sonographic and angiographic findings are presented and correlated.

Semiquantitative evaluation of ophthalmic collateral flow in carotid artery occlusion: ultrasonic doppler study

The reliability of quantitative evaluation by doppler ultrasound with regard to the ophthalmic collateral blood flow in patients with carotid artery occlusion was estimated. The ultrasonic doppler flow signals of the ophthalmic collateral flow of 54 carotid occlusions were classified into four types and three degrees--high, moderate, and low reversed flow patterns--and were compared with the angiographic findings of the collateral flow classified into three grades--good, poor, and none. With the exception of three cases, the ultrasonic doppler flow patterns of the collateral flow correlated well with the angiographic findings in 54 occluded carotid arteries.