Collateral blood supply through the ophthalmic artery: a steal phenomenon analyzed by color Doppler imaging

OBJECTIVE: This study aimed to evaluate the retrobulbar circulatory effects of reversed ophthalmic artery flow (ROAF) on the ophthalmic artery branches by means of color Doppler imaging. DESIGN: The design was a case-controlled study. PARTICIPANTS: Among 56 consecutive patients with severe (>70% stenosis) occlusive carotid artery disease, 15 patients (26.8%) with ROAF were identified. The control group consisted of 15 patients with similar degrees of carotid artery stenosis and forward ophthalmic artery flow. INTERVENTION: Arteriography and measurement of the retrobulbar hemodynamic parameters with color Doppler imaging were performed. MAIN OUTCOME MEASURES: Blood flow velocities and resistive index in the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. RESULTS: Arteriography confirmed the diagnosis of ROAF in all 15 patients. There was no patient with ROAF diagnosed by arteriography and not diagnosed by color Doppler imaging. The frequency of bilateral severe occlusive carotid artery disease was significantly higher in the ROAF group (40%) compared to the control group (6.6%) (P = 0.04). Patients with ROAF showed significantly reduced vascular resistance in the ophthalmic artery (P = 0.03), higher vascular resistance, and lower blood flow velocities in the central retinal and temporal short posterior ciliary arteries (P < 0.05). CONCLUSION: This study suggests that patients with ROAF show a steal phenomenon, characterized by a shunt to the low-resistance intracranial circuit and reduction of retrobulbar blood flow.     

Noninvasive angiography for the diagnosis of vertebral artery disease using Doppler ultrasound (vertebral artery Doppler)

A transoral noninvasive procedure in the oropharynx using local anesthesia was applied to detect flow in the vertebral arteries with a bidirectional continuous-wave Doppler ultrasound system. Common carotid artery compression was used to identify the vertebral artery. Flow direction, amplitude of flow signals, diastolic flow, and reaction of flow on common carotid artery compression served as diagnostic parameters. The procedure was applied in 90 patients of whom 42 underwent angiography. The method has proved to be 82% accurate. It was most reliable in the diagnosis of occlusion or aplasia, subclavian steal and normalcy, and was less reliable in the detection of stenosis or hypoplasia of a vertebral artery. Eleven patients with subclavin steal, five patients with a missing vertebral artery three patients with hypoplasia or stenosis, and 15 patients with normal angiorgraphical findings were correctly diagnosed by Doppler; normal Doppler findings were present in three patients with a mission or stenosed vertebral artery. Those patients (five) with Doppler indications of subclavian steal (one patient), missing vertebral artery (two patients), or stenosis (two patients) had normal angiograms. Application of the Doppler procedure, after 11 subclavin endarterectomies, informed the surgeon immediately about the hemodynamic effect of surgical intervention. Rethrombosis was diagnosed in two patients by postoperative Doppler examination.     

The hemodynamic characteristics of the central retinal artery and ophthalmic artery in atherosclerotic lesions of the carotid arteries based on the data from ultrasonic study methods

Central retinal artery and orbital artery were examined by ultrasonograph in 348 patients with atherosclerosis of the carotid arteries. Doppler shift of frequency spectrum was detected in the central retinal artery, which is typical of the ischemic syndrome of the eye. Its characteristics include decreased diastolic component of velocity and increased resistance index. The possibility of using duplex scanning with color Doppler flow mapping for assessing the treatment efficacy is demonstrated. A direct relationship between the degree of stenosis in the internal carotid artery and blood flow in the orbital artery is revealed. The detected changes do not notably affect the Doppler spectrum characteristics in the central retinal artery.     

Vasospasm diagnosis: theoretical and real transcranial Doppler sensitivity

In 40 patients middle cerebral artery trunk (M1) flow velocity was recorded just before 54 carotid angiography in 54 cases exhibiting vasospasm after aneurysm rupture. Angiographic vasospasm distribution was studied; cases of symptomatic vasospasm were noted and were compared with transcranial Doppler data. Angiographic vasospasm was present in M1 in 41/54 carotid angiograms. Postulating that all the cases of M1 angiographic vasospasm should be identified by transcranial Doppler, the theoretical sensitivity of TCD was 76%. In this series however the real sensitivity of TCD in vasospasm diagnosis was only 70%: besides 13 cases where vasospasm was not present in M1 (mainly after ACoA Aneurysm rupture), TCD failed to identify 3 cases of M1 angiographic vasospasm. Vasospasm may not be located in M1 even when severe and symptomatic (4 cases in this series). Transcranial Doppler remains a mediocre tool for identifying vasospasm after anterior communicating artery aneurysm rupture (sensitivity: 55%). Its reliability is better after internal carotid aneurysm rupture (sensitivity: 72%) and excellent after middle cerebral artery aneurysm rupture (sensitivity: 93%). In order to test the drugs or methods used to prevent or combat vasospasm, angiography has to be considered when during the vasospasm risk period TCD does not demonstrate vasospasm in M1, either in patients in whom clinical deterioration is occurring without other obvious explanation, or in all patients.     

Renal vascular Doppler imaging: clinical benefits of power mode

Power Doppler ultrasound (US) is a new technology that is superior to conventional color Doppler imaging in the detection of blood flow. Because of its greater sensitivity to flow and reduced angle dependence, power Doppler US demonstrates optimal color filling of renal pedicular vessels and allows improved evaluation of the renal parenchymal microvasculature. Power Doppler US was used as an adjunct to conventional color Doppler imaging in technically challenging cases and to improve evaluation of renal vascular disorders in a series of 916 patients. The primary clinical advantages of using power Doppler US compared with conventional color Doppler imaging include better morphologic appreciation of atherosclerotic changes in the renal artery wall, allowing improved diagnostic performance especially in hemodynamically nonsignificant plaques; ability to differentiate between subocclusive renal artery stenosis and occlusion; increased confidence in the diagnosis of renal vein thrombosis and in the assessment of caval tumor thrombus; and better appreciation of renal cortical perfusion defects. In addition, because of its greater sensitivity to perivascular artifact, power Doppler US has the potential to increase the detection rate for intrarenal arteriovenous fistulas.     

Complete MR angiography and Doppler ultrasound as the sole imaging modalities prior to carotid endarterectomy

OBJECTIVE: To assess the combination of duplex Doppler ultrasound (DUS) and complete carotid magnetic resonance angiography (MRA) for the non-invasive imaging of carotid disease and their effect on outcomes. Determine inter-reader agreement of carotid MRA. MATERIALS AND METHODS: One-hundred and ten carotid bifurcations were evaluated using DUS, 2D and 3D time-of-flight MRA from the aortic arch to the Circle of Willis in 55 patients. Percentage stenoses were determined by two blinded readers using standardized criteria. Clinical follow-up was by chart review. RESULTS: Correlation of Doppler and MRA was excellent (r=0.903, P<0.001). Inter-reader agreement (K) for MRA was good: internal carotid artery (ICA) (0.750), external carotid artery (ECA) (0.674) and common carotid artery (CCA) (0.410). Differences in CCA readings were due to minor differences in categorizing lesions as CCA versus ICA or ECA. MRA and Doppler detected nine occluded ICAs. Two DUS occlusions had ICA flow by MRA; one due to a reconstituted precavernous ICA, one a near occluded vessel. Five patients (9%) had surgical management modified by MRA with four not having surgery: three distal ICA/Siphon occlusions and one less severe stenosis by MRA. One tandem lesion not visualized by DUS was surgically significant. Nine aortic arch abnormalities had no surgical impact, possibly due to small sample size. Of 41 endarterectomies, there were no complications from errors of diagnosis. CONCLUSION: Carotid MRA correlates well with DUS with good inter-reader agreement. MRA confirms Doppler findings, expands anatomical information and identifies tandem lesions from the aortic arch to the Circle of Willis which can affect surgical management. This approach to carotid artery imaging appears to have no negative effect on surgical outcome.     

Effect of opioid blockade on insulin and growth hormone (GH) secretion in patients with polycystic ovary syndrome: the heterogeneity of impaired GH secretion is related to both obesity and hyperinsulinism

Amplitude-coded color Doppler sonography (ACD) has become an useful adjunct to gray-scale US and conventional color Doppler sonography (CD) for the assessment of vascular diseases and pathologic conditions that might affect or alter tissue vascularization or perfusion. Basically, all US units that generate conventional color Doppler information through autocorrelation technique are capable of displaying ACD. This technique is also referred to as power Doppler, amplitude-mode color Doppler US, color Doppler energy (CDE), or US angiography. Amplitude-coded color Doppler sonography has already emerged as a valuable adjunct to conventional CD, particularly for evaluating flow in parts of the body where CD signal is weak because of slow flow, small blood vessels, or both.     

The hemodynamics and anatomy of the circle of Willis. The technic and clinical value of selective MR angiography

This study evaluates the usefulness of MR angiography in analysing the individual collateral flow dynamics and anatomy of the circle of Willis in 56 patients with high-grade extracranial carotid stenosis or occlusion. Selective MRA of the carotid or vertebrobasilar area was performed by means of presaturation up to the brain-supplying arteries at the level of the middle neck (angled presaturation slabs). Results obtained with selective and non-selective MRA in 56 consecutive patients were compared with the findings at transcranial Doppler ultrasonography and arterial angiography. Ischaemic cerebral infarctions were classified by computerized tomography and correlated with the results of collateral flow analysis: Sensitivity of selective MRA in detecting intracranial collateral flow via anterior or posterior communicating artery was 96 and 97%, respectively; sensitivity in depicting extracranial transorbital flow was lower (71%). Non-selective MRA was 100% sensitive in detecting a non-filling of the horizontal (A1) segment of the anterior cerebral artery and in identifying an origin of the posterior cerebral artery from the intracranial carotid artery. Slow flow infarctions occurred more frequently in patients with transorbital and posterior-to-anterior collateral flow than in patients with collateral flow via anterior communicating artery.     

Visualization of tumor vessels in hepatocellular carcinoma. Power Doppler compared with color Doppler and angiography

PURPOSE: To assess the visualization of tumor vessels in hepatocellular carcinoma (HCC) by power Doppler sonography. MATERIAL AND METHODS: We examined 40 patients with 47 HCC lesions by means of power Doppler sonography and compared its visualization of tumor vessels with those of color Doppler and angiography. RESULTS: In 38 (81%) of the 47 lesions, power Doppler sonography improved the visualization of tumor vessels compared with color Doppler sonography; in the remaining lesions no significant difference was noted. In lesions located within 7 cm in depth, there was no significant difference between power Doppler sonography and angiography. In 10 (83%) out of 12 small (< or = 2 cm in diameter) lesions and in 11 (85%) out of 13 hypovascular lesions, power Doppler sonography performed considerably better than angiography. In deeper-seated lesions, however, angiography was significantly superior to power Doppler sonography. CONCLUSION: Power Doppler sonography is more sensitive in detecting the fine tumor vessels in most HCCs than color Doppler sonography. In addition, power Doppler sonography can replace angiography in evaluating tumor vascularity in HCCs except in lesions that are deep-seated or located near the heart. In these lesions, angiography can complement power Doppler sonography in demonstrating tumor vessels.     

Color Doppler imaging assessment of blood flow in vascularized pedicle grafts for avascular necrosis of the femoral head: angiographic correlation

The aim of this study was to examine whether color Doppler imaging can be used to assess vascular patency after use of pedicle pelvic bone grafts in the operative treatment of avascular necrosis of the femoral head. We performed color Doppler imaging and selective angiography in 10 consecutive patients (12 hip joints) treated for avascular necrosis of the femoral head. In comparison to angiographic results, nine patent and two occluded grafts were demonstrated correctly by color Doppler imaging. In one case, a graft confirmed as patent by angiography was not demonstrable by color Doppler imaging. Accuracy, sensitivity, and specificity of color Doppler imaging were high when compared to angiography as a standard. Color Doppler imaging is suited to evaluate vascular patency after use of vascularized pedicle bone grafts in the treatment of avascular necrosis of the femoral head.     

Spontaneous and heparin-induced recanalization of the completely occluded internal carotid artery--a neglected phenomenon? 2 case reports and review of the literature

This report presents two cases of totally occluded internal carotid arteries, verified by angiography. In both cases the vessel was recanalised under heparinisation. This was first detected by duplex carotid sonography. Angiographic follow-up showed a high-grade stenosis at the origin of the internal carotid artery. Both female patients were then operated successfully. It is important to consider the possibility of spontaneous recanalisation of an occluded internal carotid artery because there are clear indications for operative treatment in such a case. In case of total occlusion, as a rule no operative treatment is possible.     

Comparison of magnetic resonance volume flow rates, angiography, and carotid Dopplers. Preliminary results

BACKGROUND AND PURPOSE: We compared the results of conventional angiography, carotid Doppler, and magnetic resonance angiography volume flow rates to determine the clinical utility of volume flow rate assessment of blood flow to the anterior circulation in patients with carotid occlusive disease. METHODS: From 11 symptomatic patients, a total of 22 extracranial carotid arteries were studied with all three techniques. The studies were independently read, and regression analysis was used to compare the measurements. RESULTS: Carotid Doppler measurements of the distal extracranial carotid arteries were proportional to the inverse of the extracranial carotid volume flow rate (r = .53, R2 = 29%, P < .01), volume flow rates were proportional to the inverse of measured percent stenosis on angiography (r = .84, R2 = 71%, P < .01), and Dopplers were proportional to angiography (r = .94, R2 = 90%, P < .01). Symptomatic Doppler systolic velocity was significantly higher (P < .002), symptomatic measured stenosis was significantly higher (P < .002), and symptomatic volume flow rate was significantly lower (P < .01) than their respective asymptomatic-side values. These preliminary observations, however, may well change once a large data set, especially one in which more patients with high-grade carotid stenosis are included, is studied. CONCLUSIONS: Assessment of carotid volume flow rates by magnetic resonance angiography quantifies flow reduction secondary to atherosclerotic occlusive disease. The easily obtained flow data add both documentation of arterial flow characteristics related to internal carotid stenosis and information regarding the adequacy of collateral pathways.     

Mycotic aneurysm of the external carotid artery

Mycotic aneurysms of the extracranial carotid arteries are extremely rare. A case is reported of a false aneurysm of the left external carotid artery. This developed secondary to cervical lymphadenitis which did not settle with high dose antibiotic therapy. The diagnosis was made on investigation with carotid doppler ultrasound and confirmed with computerized tomography. Digital subtraction angiography was performed to highlight the vascular anatomy. In addition percutaneous balloon catheter control of blood flow in the external carotid artery was used as an adjunct to surgical management.     

The diagnosis of obstructions of the vertebral and subclavian arteries by means of directional Doppler sonography (author's transl)

The Doppler examination of the vertebral and subclavian arteries was compared with the angiographic findings in 40 cases. The vertebral flow was recorded at its atlas slope, the subclavian artery at the supraclavicular fossa. Twenty-seven normal Doppler results were confirmed by angiography in 26 cases. In one case there was a 70% stenosis at the origin of the vertebral artery. Occlusions, stenoses, and severe hypoplasia of the vertebral artery can be detected, but not distinguished from each other by the Doppler examination. Diagnostically relevant findings are either nondetectable flow above the vertebral artery or only minor pulsations with amplitudes less than 25% of the normal side. Eleven cases showed a flow reversal in a vertebral artery. Five of them were angiographically controlled and all showed a typical subclavian steal syndrome. Although the precision of the results of the examination of the vertebral artery is not as good as for the carotid arteries, it is a rough, suitable atraumatic screening method particularly for the subclavian steal syndrome.     

Noninvasive assessment of collateral blood flow of the cerebral hemisphere by Doppler ultrasound

Directional flow in the frontal artery, a terminal branch of the ophthalmic artery, was assessed nonivasively by Doppler ultrasound druing brief digital compression of the ipsilateral common carotid artery in 62 patients. Directional frontal artery flow during carotid compression was compared with mean distal internal carotid back pressure measured at subsequent carotid endarterectomy. Mean carotid back pressure in 28 patients with normal frontal artery flow direction during carotid compression, 68 +/- 14 millimeters of mercury, was significantly higher than that observed in 24 patients in whom frontal artery flow was completely obliterated and ten in whom frontal artery flow was reversed. Distal internal carotid back pressure exceeded 48 millimeters of mercury in all patients with normal frontal artery flow direction during carotid compression. Conversely, carotid back pressure was below 41 millimeters of mercury in all but one patient in whom frontal artery flow was obliterated or bliterated or reversed during carotid compression. The results of this study indicate that Doppler ultrasound assessment of frontal artery flow direction during simultaneous carotid compression provides a rapid, sale noninvasive estimate of the adequacy of collateral hemispheric circulation.     

Use of ultrasound methods in vascular and circulatory diseases (author's transl)

The paper summarizes the principles, techniques and efficiency of ultrasound methods as indicator systems in the assessment of the peripheral and cerebral arteries; our studies predominantly refer to the use of these simple, non-invasive procedures in combination with sphygmo-oscillography and dynamographic circulation analysis, respectively. Ultrasound Doppler flowmetry (Pulse Doppler method), which permits relative measurements of the flow velocity in the peripheral haemodynamic regions, is of great importance in the rapid ascertainment of the patency of the major arterial trunks and the non-palpable vessels and also in the diagnosis, localization and follow-up control of stenoses and occlusions. Changes in the flow velocity due to organic or functional factors can be recorded by this method acoustically, oscilloscopically and graphically; measurements of the systolic blood pressure in the limb arteries by the Doppler technique provide semi-quantitative information in regard to the condition of the circulation. The registration of Doppler signals over the supra-orbital artery before and after compression of the superficial temporal artery and the common carotid artery has become established as a screening procedure for stenoses of the internal carotid artery. Ultrasound echography, which enables pulse registration and determination of vessel diameters, especially of the carotid siphon, can also be used for the detection of obstructions in the region of the internal carotid artery, as well as the vertebral artery.     

A case of large neonatal arteriovenous malformation with heart failure. Color Doppler sonography, MRI and MR angiography as early non-invasive diagnostic procedures

We report a case of a large arteriovenous malformation (AVM) of neonatal onset with heart failure. Transfontanel color Doppler sonography revealed abnormal vessels in the early stage of the investigation. Magnetic resonance imaging (MRI) revealed numerous flow voids suggesting abnormal vessels, and magnetic resonance angiography (MRA) disclosed numerous bizarre abnormal vessels. Color Doppler sonography is a convenient and appropriate procedure for the early bedside diagnosis of neonatal AVMs. MRI and MRA can replace cerebral angiography for the diagnosis of neonatal AVMs.     

Nonatheromatous carotid artery disease

Common and uncommon nonatheromatous diseases affecting the cervical carotid artery are discussed. Specifically, the radiographic and pertinent clinical features of cervical carotid artery congenital variants, dissection, fibromuscular dysplasia, Takayasu's arteritis, and infection are described. Catheter angiography continues to have an important role in the diagnosis of many of these conditions. Magnetic resonance imaging techniques are emerging as a useful adjunct to catheter angiography and occasionally may be the primary imaging modality for diagnosis.     

Predicting the effect of carotid artery occlusion during carotid endarterectomy: comparing transcranial doppler measurements and cerebral angiography

BACKGROUND and PURPOSE: We correlated the mean transcranial Doppler blood flow velocity (FVm) during carotid endarterectomy with the functional collateral pathway(s) documented by angiography. METHODS: Three patient groups were established: group 1 was dependent on the anterior communicating artery, group 2 on the anterior communicating artery and ipsilateral posterior communicating artery, and group 3 on the ipsilateral posterior communicating artery. Continuous middle cerebral artery FVm and electroencephalographic monitoring were performed in 45 patients during carotid endarterectomy. RESULTS: Clamped FVm was lowest in group 3 at 17+/-9 cm/s versus 36+/-16 and 33+/-11 cm/s for groups 1 and 2 (P<0.01). FVm values in groups 1 and 2 were similar. There was significant cerebral arterial vasodilation in group 3 patients on the basis of a pulsatility index of 0.38+/-0.15. The maximum FVm after clamp release was similar among the 3 groups. Normalized blood flow velocity 1 minute before release of the clamp was increased from the minimum flow velocity after clamping only in group 1 and 2 patients. CONCLUSIONS: The ipsilateral posterior communicating artery is a minor collateral pathway during acute carotid occlusion that contributes little to the collateral flow if there is a functional anterior communicating artery. Collateral flow through the middle cerebral artery is not recruited during occlusion in group 3 patients. The reperfusion FVm transient is independent of the primary collateral pathway. Documentation of functional collateral pathways on the basis of Doppler or angiographic examination may be advantageous in future studies since it can provide the basis for comparison among studies.