The Posterior Cerebral Artery and its Main Cortical Branches Identified with Noninvasive Transcranial Color-Coded Duplex Sonography.

PURPOSE: To differentiate PCA segments and cortical branches by means of transcranial color-coded duplex sonography (TCCD) and to measure flow parameters at rest and during visual stimulation. MATERIALS AND METHODS: 60 healthy subjects with a good acoustic temporal bone window were examined. The main stem of the PCA (P1, P2 and P3) and 4 main cortical branches - the anterior temporal artery (ATA), the occipital temporal artery (OTA), the parietooccipital artery (POA) and the calcarine artery (CA) - were assessed using an axial transtemporal approach. Systolic and diastolic blood flow velocities (BFVs) were recorded at rest and during visual stimulation. RESULTS: Identification of the P1 segment of the PCA was successful in 97.5% (117/120) of cases. The P2 and P3 segments were visualized in all cases. The 4 main cortical branches could be identified to varying degrees: ATA in 88%, OTA in 96%, POA in 69% and CA in 62%. There was an evoked flow response in the P2 main stem and in all cortical branches. The most pronounced increase in diastolic/systolic BFV after visual stimulation test was seen in the CA (42%/35%), followed by P2 (30%/24%), the POA (27%/27%), the OTA (16%/13%) and the ATA (9%/8%). CONCLUSION: Insonation through the temporal bone window with TCCD confidently allows the assessment of the P1 to P3 segments of the PCA as well as the 2 proximal branches, the ATA and the OTA. An ultrasound-based classification of PCA anatomy and its cortical branches may be used as a noninvasive method for the evaluation of posterior circulation pathology.

Venous drainage in multiple sclerosis: a combined MRI and ultrasound study.

BACKGROUND: Chronic cerebrospinal venous insufficiency (CCSVI) was proposed as the causal trigger for developing multiple sclerosis (MS). However, current data are contradictory and a gold standard for venous flow assessment is missing. OBJECTIVE: To compare structural magnetic resonance venography (MRV) and dynamic extracranial color-coded duplex sonography (ECCS) in a cohort of patients with MS. METHODS: We enrolled 40 patients (44 ± 10 years). All underwent contrast-enhanced MRV for assessment of internal jugular vein (IJV) and azygos vein (AV) narrowing, graded into 3 groups: 0%-50%, 51%-80%, and >80%. ECCS analysis of blood flow direction, cross-sectional area (CSA), and blood volume flow (BVF) in both IJV and vertebral veins (VV) occurred in the supine and upright body position. RESULTS: MRV identified 1 AV narrowing. IJV analysis yielded 12 patients for group 1 (30%), 19 patients for group 2 (48%), and 9 patients for group 3 (22%). By ECCS criteria, 4 patients (10%) presented with venous drainage abnormalities. Jugular BVF was different only between groups 1 and 3 (616 ± 133 vs. 381 ± 213 mL/min, p = 0.02). No other parameters in supine position and none of the parameters in the upright body position, apart from the IJV-BVF decrease in groups 1 and 3 (479 ± 172 vs. 231 ± 144 mL/min, p = 0.01), were different. CONCLUSIONS: Our ECCS data contradict the postulated 100% prevalence of CCSVI criteria in MS. MRV seems more sensitive to detect IJV narrowing compared to ECCS. A measurable hemodynamic effect only exists in vessel narrowings >80%. Our combined data argue against a causal relationship of venous narrowing and MS, favoring the rejection of the CCSVI hypothesis.

["Chronic cerebrospinal venous insufficiency" in multiple sclerosis - is multiple sclerosis a disease of the cerebrospinal venous outflow system?]. / "Chronische zerebrospinale venöse Insuffizienz" bei Multipler Sklerose - Ist die Multiple Sklerose eine Erkrankung des zerebrospinalen venösen Abflusssystems?

Chronic impaired venous outflow from the central nervous system has recently been claimed to be associated with multiple sclerosis (MS) pathology. This resulted in the term chronic cerebrospinal venous insufficiency (CCSVI) in MS. The concept of CCSVI is based on sonography studies showing that impaired venous outflow leading to pathological reflux is almost exclusively present in MS patients but not in healthy controls. Based on these findings, a new pathophysiological concept has been introduced suggesting that chronic venous outflow obstruction and venous reflux in the CNS result in pathological iron depositions leading to inflammation and neurodegeneration. The theory of CCSVI in MS has rapidly generated tremendous interest in the media and among patients and the scientific community. In particular, the potential shift in treatment concepts possibly leading to an interventional treatment approach including balloon angioplasty and venous stent placement is currently being debated. However, results from recent studies involving several imaging modalities have raised substantial concerns regarding the CCSVI concept in MS. In this review article, we explain the concept of CCSVI in MS and discuss this hypothesis in the context of MS pathophysiology and imaging studies which have tried to reproduce or refute this theory. In addition, we draw some major conclusions focusing in particular on the crucial question as to whether interventional treatment options are expedient. In conclusion, the present conclusive data confuting the theory of CCSVI in MS should lead to reluctance with respect to the interventional treatment of possible venous anomalies in MS patients.

Does routine transcranial duplex ultrasound heat up the patient brain?

PURPOSE: The effect of transcranial duplex ultrasound (US) on the intraventricular temperature in patients was analyzed. Temperature increases during examination have been identified as a potential risk factor but only data from model studies is currently available. MATERIALS AND METHODS: Patients who had an intracranial pressure/temperature transducer implanted and underwent US assessment were included. In an examination series (B-mode, combined B- and color mode, combined B- and color mode plus Doppler, 3 min for each mode), the intracranial thermodilution thermistor was focused while intraventricular temperature and body temperature (bladder catheter or rectal probe) were recorded continuously and temperature changes were analyzed. RESULTS: Thirty-one US examinations were performed in 14 patients. Twenty-six examinations in 9 patients in which the intracranial temperature probe was depicted were included. Initial patient temperatures ranged from 35.1dgC to 38.7dgC. No significant increase or decrease in intracranial temperature was seen after the first (B-mode), second (B- and color mode) and third (B- and color mode plus Doppler) duplex US examination. T-test for paired samples showed a constant temperature throughout US examination (two-sided significance: 1.000, 1.000, 0.731). CONCLUSION: Routine transcranial duplex ultrasound does not increase the intracranial temperature in patients.

Incompetence of internal jugular valve in patients with primary exertional headache: a risk factor?

The pathophysiology of primary exertional headache (EH) is unknown. Physical exertion is associated with Valsalva-like manoeuvres (VM). VM leads to increased intrathoracic pressure and reduces cerebral venous drainage. Internal jugular vein valve incompetence (IJVVI) leads to retrograde venous flow during VM with transient increase of intracranial pressure. We analysed the prevalence of IJVVI in EH patients using duplex ultrasound. Bilateral measurements were performed at rest and during VM in 20 patients and 40 controls. Incompetence was concluded if retrograde venous flow could be seen in the jugular Doppler spectrum during repeated VM. Seventy percent of EH patients and 20% of controls demonstrated IJVVI, yielding a significant difference (P = 0.0004). IJVVI was always observed on the dominant venous drainage side. Our study suggests that intracranial venous congestion caused by retrograde jugular venous flow might play a role in the pathophysiology of EH with IJVVI as a risk factor.

Internal jugular vein valve incompetence and intracranial venous anatomy in transient global amnesia.

BACKGROUND: Recently a causal relation between internal jugular vein valve incompetence (IJVVI) and transient global amnesia (TGA) has been suggested. IJVVI is postulated to provoke a transient mesiotemporal ischaemia by venous congestion. This mechanism requires a patent venous pathway from the affected IJV through the transverse sinus, confluens, straight sinus (SS), vein of Galen into the basal vein of Rosenthal and the internal cerebral veins. OBJECTIVE: To study IJVVI in TGA patients in relation to the intracranial venous anatomy. METHODS: IJVVI was defined if a repeated Valsalva manoeuvre (VM) led to a retrograde jugular flow detected by extracranial duplex ultrasound. Non-contrast venous MR angiography (MRA) was performed to analyse intracranial drainage patterns of the SS in relation to the side of the IJVVI. SS drainage was differentiated into three groups: predominantly right, left, and bilateral drainage. Ultrasound studies were performed in 25 TGA patients and 85 age matched controls. Twenty patients underwent venous MRA. RESULTS: Sixty eight per cent of patients and 33% of controls showed unilateral or bilateral IJVVI (p = 0.0025). In 36% of patients a TGA preceding VM was reported. Drainage pattern of SS and side of IJVVI corresponded in five of eight patients (63%) with VM and four of 12 patients without VM (33%, p = 0.0994). CONCLUSION: Our study confirms the significantly higher prevalence of IJVVI in TGA patients. However, no specific IJVVI related intracranial venous drainage patterns could be found to further support the hypothesis of a direct causal relation between IJVVI and TGA.

[Adenocarcinoma-associated nonbacterial thrombotic endocarditis as the cause of recurrent strokes]. / Adenokarzinom-assoziierte nichtbakterielle thrombotische Endokarditis als Ursache rezidivierender Schlaganfälle.

We describe a 60-year-old female patient without vascular risk factors diagnosed with cardioembolic ischemic stroke due to an atrial septal aneurysm with a right-to-left shunt. However, further investigation after recurrent strokes revealed a nonbacterial thrombotic endocarditis (NBTE) caused by a metastatic adenocarcinoma. The presented case illustrates the difficulties in establishing the diagnosis of NBTE premortally and points out the importance of repeated echocardiographic evaluations of cardiac valves and serological examination of tumor markers in patients with recurrent strokes of unknown origin.

Effects of prolonged head-down tilt on internal jugular vein cross-sectional area.

BACKGROUND: Head-down tilt is often used to assist cannulation of the internal jugular vein (IJV). However, the optimal duration of tilt before cannulation is not well defined. METHODS: Fifteen healthy volunteers were studied by B-mode duplex sonography to assess changes in cross-sectional area (CSA) of the right IJV during 10 degrees head-down tilt. RESULTS: Median CSA in the supine position was 102 mm(2) [range 16-266, mean (SD) 113 (69)]. CSA increased to 139 mm(2) [23-388, 158 (93)] immediately after tilting (P<0.0001, repeated measures ANOVA). No significant further change was noted in the next 20 min. CSA returned to baseline level after return to the supine position. CONCLUSION: The 10 degrees head-down tilt manoeuvre in healthy volunteers causes an immediate, significant increase in CSA in the right IJV. A longer tilt did not cause further increase in jugular CSA.

Venous collateral blood flow assessed by Doppler ultrasound after unilateral radical neck dissection.

Removal of the internal jugular vein (IJV) in unilateral radical neck dissection (rND) necessitates redirection of cerebrovenous blood to collateral pathways. If adaptation is insufficient, neurologic sequelae develop that are due to impaired venous drainage and increased intracranial pressure. The authors studied venous hemodynamic effects of unilateral rND using Doppler and duplex ultrasound in 17 patients. Blood flow velocities (BFVs) were recorded from the distal IJV (dIJV) and the vertebral vein (VV) before and 9 to 88 days after surgery. A preoperative compression test of the dIJV was performed to identify the side of dominant drainage. The BFV increased in the contralateral dIJV after right-sided rND (n = 10) by 111% (range, 50% to 320%), and after left-sided rND (n = 7) by 34% (range, 5% to 105%). In the contralateral VV, a rise of BFV by 75% was found. Our results confirm the role of the contralateral dIJV as the predominant collateral pathway. The VVs serve as an important additional major outflow. Doppler ultrasound may help to identify patients at risk of insufficient cerebrovenous drainage after rND.

The inferior petrosal sinus: assessment by transcranial Doppler ultrasound using the suboccipital approach.

Recently, intracranial veins and sinuses have been successfully insonated using the transtemporal and transoccipital approaches by transcranial Doppler ultrasound. The purpose of this study was to prove the capacity of the Doppler method to evaluate the inferior petrosal sinus via the suboccipital approach. Venous transcranial ultrasound was performed with a range-gated 2-MHz transducer in 80 healthy volunteers and patients without central nervous system disorders ranging in age from 15-84 years (mean +/- standard deviation [SD], 37.6 +/- 15.2 years). A venous signal with a flow directed toward the probe was considered to originate from the inferior petrosal sinus because of its proximity to the basilar artery. The inferior petrosal sinus was insonated in 96.3% of the cases at least on one side. It was found bilaterally in 48 (60%), on the right side in 74 (92.5%), and on the left side in 51 (63.8%) subjects, respectively. Mean blood flow velocity ranged from 8-53 cm/s (mean +/- SD, 19.6 +/- 8.7 cm/s). A significant age dependency of venous velocities was found. Weak but significant side-to-side differences were observed, reflecting the known right-sided predominance of venous outflow in humans. Using the suboccipital approach, the inferior petrosal sinus can be insonated in a high percentage of subjects without major difficulties and is defined by its vicinity to the basilar artery.

Venous Doppler ultrasound assessment of the parasellar region.

The purpose of this report is to present normal values for venous blood flow velocities from the parasellar region using transcranial Doppler ultrasound (2-MHz transducer) with both transtemporal and transorbital approaches and to examine the nature of previously reported low-pulsatility signals with velocities in the arterial range from this area. Forty-three subjects ranging in age from 18 to 56 years (mean +/- SD, 31.9 +/- 10.1 years) were examined. In all subjects, a venous signal directed away from the probe with the source lateral to the internal carotid artery siphon was detected on at least one side. A total of 72 parasellar venous signals were insonated. Signals were considered to belong to the main inflow and outflow vessels of the cavernous sinus. The mean blood flow velocity ranged from 6 to 81 cm/s (mean +/- SD, 27.3 +/- 17.4 cm/s). Typical transients in the Valsalva test confirmed the venous character of the signals. No significant gender, side-to-side or age dependency was observed. A separate analysis was done for venous high-velocity signals defined by a mean blood flow velocity greater than 30 cm/s. They were detected in 21 out of 43 subjects (48.9%) via a transtemporal approach and in 6 of them (14%) via the transorbital route, too. Again, no significant gender, side-to-side or age dependency was noted. In summary, we found a greater variability of venous blood flow velocities in the parasellar region compared to other basal cerebral veins, e.g. the basal vein of Rosenthal. The previously reported low-pulsatility signals with velocities in the arterial range proved to be of venous origin.

Venous microembolic signals detected in patients with cerebral sinus thrombosis.

BACKGROUND AND PURPOSE: We sought to assess the usefulness of the Doppler technique in the monitoring of microembolic signals in the main venous outflow pathways in superior sagittal sinus thrombosis. METHODS: Transcranial Doppler ultrasound was performed with a range-gated 2-MHz transducer in 6 patients with superior sagittal sinus thrombosis, in 5 subjects with platelet hyperaggregability, and in 20 healthy volunteers. Emboli monitoring was performed mainly in one distal internal jugular vein for 10 to 15 minutes. RESULTS: Three of the six patients (50%) with superior sagittal sinus thrombosis had microemboli. None of the patients with platelet hyperaggregation or healthy volunteers revealed microemboli. CONCLUSIONS: Microemboli can be found in superior sagittal sinus thrombosis by Doppler ultrasound. Their prognostic significance remains to be determined.