Transcranial color-coded duplex sonography of the middle cerebral artery: more than just the M1 segment.

OBJECTIVES: Routine sonography of the middle cerebral artery in acute ischemic stroke usually focuses on the main stem (M1 segment). However, stenoses and occlusions affect not only proximal but also more distal vessel branches, such as the M2 segments. Transcranial color-coded duplex sonography allows visualization of these segments; however, a formal analysis and description of normal blood flow values are missing. The purpose of this study was to analyze middle cerebral artery branching patterns with transcranial color-coded duplex sonography and to establish reference flow velocity values in the detectable M2 branches as well as the early temporal M1 branch. METHODS: Transcranial color-coded duplex sonography in the axial and coronal planes was performed in 50 participants without vascular disease and with a good temporal bone window (ie, fully visible M1 middle cerebral artery segment and A1 anterior cerebral artery segment). We analyzed the course and branching pattern of the M1 segment, including anatomic variants such as an early temporal M1 branch, and measured the length and flow parameters of the detectable M2 branches. RESULTS: Assessment of 100 hemispheres allowed classification into 3 anatomic patterns: M1 bifurcation (63%), M1 trifurcation (32%), and medial M1 branching into 2 major segments (2%). A clear distinction was not possible in 3 cases (3%). An early temporal M1 branch was detected in the coronal plane in 26%. CONCLUSIONS: Transcranial color-coded duplex sonography is a useful tool for analyzing anatomic variants and branching patterns of the middle cerebral artery as well as flow characteristics of M2 segments. Therefore, it also has potential to increase the diagnostic yield for the detection of middle cerebral artery disease in these vessel segments.

Development and validation of a dispatcher identification algorithm for stroke emergencies.

BACKGROUND AND PURPOSE: Recent innovations such as CT installation in ambulances may lead to earlier start of stroke-specific treatments. However, such technically complex mobile facilities require effective methods of correctly identifying patients before deployment. We aimed to develop and validate a new dispatcher identification algorithm for stroke emergencies. METHODS: Dispatcher identification algorithm for stroke emergencies was informed by systematic qualitative analysis of the content of emergency calls to ambulance dispatchers for patients with stroke or transient ischemic attack (N=117) and other neurological (N=39) and nonneurological (N=51) diseases (Part A). After training of dispatchers, sensitivity and predictive values were determined prospectively in patients admitted to Charité hospitals by using the discharge diagnosis as reference standard (Part B). RESULTS: Part A: Dysphasic/dysarthric symptoms (33%), unilateral symptoms (22%) and explicitly stated suspicion of stroke (47%) were typically identified in patients with stroke but infrequently in nonstroke cases (all <10%). Convulsive symptoms (41%) were frequent in other neurological diseases but not strokes (3%). Pain (26%) and breathlessness (31%) were often expressed in nonneurological emergencies (6% and 7% in strokes). Part B: Between October 15 and December 16, 2010, 5774 patients were admitted by ambulance with 246 coded with final stroke diagnoses. Sensitivity of dispatcher identification algorithm for stroke emergencies for detecting stroke was 53.3% and positive predictive value was 47.8% for stroke and 59.1% for stroke and transient ischemic attack. Of all 275 patients with stroke dispatcher codes, 215 (78.5%) were confirmed with neurological diagnosis. CONCLUSIONS: Using dispatcher identification algorithm for stroke emergencies, more than half of all patients with stroke admitted by ambulance were correctly identified by dispatchers. Most false-positive stroke codes had other neurological diagnoses.

No correlation of substantia nigra echogenicity and nigrostriatal degradation in Parkinson's disease.

BACKGROUND: Substantia nigra hyperechogenicity assessed by transcranial sonography is a typical finding in up to 90% of patients with idiopathic Parkinson's disease, although its value as a surrogate marker for disease progression in Parkinson's disease is controversial. (123) I-FP-CIT-single photon emission computed tomography (SPECT) represents an established paraclinical surrogate marker to quantify the nigrostriatal dopaminergic deficit in Parkinson's disease. Whereas most studies found no correlation between extent of substantia nigra echogenicity and the putaminal FP-CIT binding ratio, a more recent analysis reported opposite results. METHODS: In 92 patients with Parkinson's disease the substantia nigra echogenicity was compared with the putaminal FP-CIT binding ratio using an investigator-independent SPECT analysis protocol and with several clinical parameters. RESULTS: No correlation was found between the substantia nigra hyperechogenicity and the FP-CIT binding ratio or the disease severity. CONCLUSIONS: Substantia nigra hyperechogenicity does not reflect the degree of the nigrostriatal degeneration or the clinical state of the disease progression.

No cerebrocervical venous congestion in patients with multiple sclerosis.

OBJECTIVE: Multiple sclerosis (MS) is characterized by demyelination centered around cerebral veins. Recent studies suggested this topographic pattern may be caused by venous congestion, a condition termed chronic cerebrospinal venous insufficiency (CCSVI). Published sonographic criteria of CCSVI include reflux in the deep cerebral veins and/or the internal jugular and vertebral veins (IJVs and VVs), stenosis of the IJVs, missing flow in IJVs and VVs, and inverse postural response of the cerebral venous drainage. METHODS: We performed an extended extra- and transcranial color-coded sonography study including analysis of extracranial venous blood volume flow (BVF), cross-sectional areas, IJV flow analysis during Valsalva maneuver (VM), and CCSVI criteria. Fifty-six MS patients and 20 controls were studied. RESULTS: Except for 1 patient, blood flow direction in the IJVs and VVs was normal in all subjects. In none of the subjects was IJV stenosis detected. IJV and VV BVF in both groups was equal in the supine body position. The decrease of total jugular BVF on turning into the upright position was less pronounced in patients (173 +/- 235 vs 362 +/- 150 ml/min, p < 0.001), leading to higher BVF in the latter position (318 ml/min +/- 242 vs 123 +/- 109 ml/min; p < 0.001). No differences between groups were seen in intracranial veins and during VM. None of the subjects investigated in this study fulfilled >1 criterion for CCSVI. INTERPRETATION: Our results challenge the hypothesis that cerebral venous congestion plays a significant role in the pathogenesis of MS. Future studies should elucidate the difference between patients and healthy subjects in BVF regulation.

Brain parenchyma sonography and 123I-FP-CIT SPECT in Parkinson's disease and essential tremor.

We aimed to investigate the accuracy of transcranial brain parenchyma sonography (TCS) for differentiation between idiopathic Parkinson's disease (PD) and essential tremor (ET) in comparison to (123)I-FP-CIT SPECT (FP-CIT SPECT). Seventy-four patients, in whom PD or ET was suspected on the basis of clinical criteria, were analyzed. The echogenicity of the substantia nigra (SN) and the striatal binding of dopamine transporters (DAT) were evaluated by TCS and FP-CIT SPECT, respectively. Three patients were excluded due to an insufficient transtemporal bone window using TCS. Forty-six and 25 patients were clinically classified as PD and ET. SPECT revealed a reduced DAT binding in 42 of all 71 included patients. Thirty-six of the 42 patients with abnormal FP-CIT SPECT findings had a pathological SN hyperechogenicity, whereas TCS findings in the remaining 6 patients were normal. In 27 of 29 patients with normal SPECT findings the SN echogenicity was regular. Referring to FP-CIT SPECT, the sensitivity and specificity of TCS for detection of PD were 86 and 93%; the positive and negative predictive values were 95 and 82%, respectively. Sensitivity and specificity in detection of clinically diagnosed PD patients were 78 and 92% for TCS and 91 and 100% for FP-CIT SPECT, respectively. In patients with pathological FP-CIT SPECT and pathological TCS, the extent of SN hyperechogenicity did not correlate with the degree of reduction in dopamine transporter binding on the side opposite of the more affected limb. TCS allows a reliable differentiation of PD and ET. The TCS SN hyperechogenicity does not correlate with the extent of dopaminergic neuron degeneration.

Diagnostic transcranial ultrasound perfusion-imaging at 2.5 MHz does not affect the blood-brain barrier.

The purpose was to assess whether standard ultrasound (US) perfusion-imaging by means of contrast-enhanced transcranial color-coded sonography (TCCS) affects the blood-brain barrier (BBB) in patients with small-vessel disease (SVD). One week after a screening MRI to exclude a preexisting BBB disruption, unilateral TCCS phase inversion harmonic imaging (PIHI) was performed in an axial diencephalic plane after intravenous bolus application of 2.5 mL SonoVue (IGEA, Bracco, Italy). Magnetic resonance imaging (MRI) was performed immediately after US. In five patients, PIHI was performed applying a mean mechanical index (MI) of 0.7 +/- 0.1 for a time period of 2.5 min. MRI was started 12 +/- 2 min after US contrast injection. Comparisons of initial and post-US MRI by four blinded readers did not show any signs of BBB disruption. It is concluded that standard contrast-enhanced US perfusion imaging in patients with SVD did not lead to MRI-detectable BBB changes. This gives further evidence for safety of diagnostic US. Future investigations with larger sample sizes and higher-field MRI might give further insights into potential bioeffects of diagnostic, as well as therapeutic, contrast-enhanced transcranial US.

Internal jugular vein valve incompetence in COPD and primary pulmonary hypertension.

PURPOSE: Under physiologic conditions, intact internal jugular vein valves (IJVVs) efficiently prevent retrograde venous flow during intrathoracic pressure increase. Chronically elevated central venous pressure found in patients with chronic obstructive pulmonary disease (COPD) and primary pulmonary hypertension (PPH) might lead to IJVV incompetence (IJVVI). The aim of this study was to analyze the prevalence of IJVVI in patients with COPD and PPH using duplex sonography (DUS). METHOD: We included 30 COPD patients, 5 PPH patients, and 100 healthy controls in the study. IJVVI was diagnosed if retrograde jugular blood flow was seen on DUS during a Valsalva maneuver. Retrograde venous flow intensity was evaluated and graded according to extent and duration of reflux. RESULTS: IJVVI was found in 18 (60%) COPD patients and in all 5 (100%) PPH patients, which was significantly different from the controls (27%; p < 0.005). The intensity of venous retrograde flow correlated with the pulmonary artery pressure. CONCLUSION: Compared with healthy controls, COPDand PPH patients demonstrated a significantlygreater prevalence of IJVVI, which seems to be caused by the elevated central venous pressure. These patients may be at higher risk to develop central nervous system diseases related to cerebral outflow obstruction.

Transcranial and extracranial ultrasound assessment of cerebral hemodynamics in vascular and Alzheimer's dementia.

BACKGROUND: Increasing life expectancy of the population leads to a higher incidence of dementia. Exact differentiation between the most common types, vascular dementia (VD) and Alzheimer's dementia (AD), is crucial to the development and application of new treatment strategies. Both conditions are thought to differ greatly by their extent of microvascular affection. Transcranial and extracranial ultrasound permits analysis of cerebral hemodynamics and should help to differentiate between VD and AD. We compare multimodal ultrasound data between VD, AD and controls, and give an overview of the literature on this topic. METHODS: Twenty VD and 20 AD patients were studied and compared with 12 age-matched controls. Transcranial color-coded ultrasound was performed to assess blood flow velocity (V(mean)) and pulsatility indices (PI) of the middle cerebral artery (MCA). Extracranial duplex and Doppler ultrasound techniques were used to assess the blood volume flow (BVF) in the anterior circulation (both internal carotid arteries [ICA]) and posterior circulation (both vertebral arteries [VA]), the global cerebral blood flow (CBF = BVF(ICA) + BVF(VA)), the global cerebral circulation time (CCT = time delay of echo-contrast bolus arrival between ICA and internal jugular vein) and global cerebral blood volume (CBV = CCT x CBF). RESULTS: MCA V(mean) in VD (36 +/- 8 cm/s) and AD (43 +/- 13 cm/s) were significantly lower than in controls (59 +/- 13 cm/s) but did not differ significantly between VD and AD groups. PI (1.1 +/- 0.2; 1 +/- 0.2; 0.9 +/- 0.2) only differed significantly between VD group and controls. CBF and CCT in VD (570 +/- 61 ml/min; 8.8 +/- 2.6 s) and AD (578 +/- 77 ml/min; 8.2 +/- 1.4 s) were similar but differed significantly from controls (733 +/- 54 ml/min; 6.4 +/- 0.8 s). BVF in the anterior and posterior circulation of VD group (412 +/- 62 and 158 +/- 38 ml/min) and AD group (428 +/- 62 and 150 +/- 41 ml/min) were significantly lower than in controls (537 +/- 48 and 199 +/- 26 ml/min) but did not differ significantly between the patient groups. DISCUSSION: Transcranial and extracranial ultrasound does not help to distinguish between VD and AD. However, our results add insight into the pathophysiology of dementia, arguing in favor of a common 'vascular' pathway in both conditions.

Serial ultrasound assessment of the basal vein of Rosenthal in HSV encephalitis.

Herpes simplex virus encephalitis (HSVE) typically affects the baso-temporal brain. The venous blood drainage of this region mainly occurs via the basal vein of Rosenthal (BVR), which can easily be monitored by transcranial color-coded duplex sonography (TCCS), and might be a useful parameter for the activity of the disease. Serial blood flow velocity (BFV) measurements of the BVR and the basal cerebral arteries were performed in five acute HSVE patients by means of transcranial color-coded duplex sonography (TCCS). Remarkable increased BFV of the BVR at the affected side was found in all patients, showing a maximum within the first 8 d of infection followed by a tendency toward normalisation during the next weeks. In comparison, changes of BFV in the basal cerebral arteries were much more heterogeneous. Our findings suggest that TCCS measurements of the BVR might be used as an additional diagnostic bed-side tool to evaluate patients with HSVE during the acute stage.

Transcranial duplex ultrasound of the ophthalmic artery.

The purpose of this study was to identify the ophthalmic artery (OA) by means of transcranial color-coded sonography using a new approach via the transtemporal bone window and to compare blood flow measurements with values obtained from the transorbital approach. A total of 105 subjects were included. Two individuals had an insufficient unilateral bone window, according to our inclusion criteria. Of the remaining 208 OAs, 206 (99%) could successfully be insonated via the transorbital approach and 190 (91%) via the transtemporal approach. Transorbital systolic and diastolic flow velocity (FVs) ranged between 15 and 67 cm/s (mean +/- SD: 35 +/- 10) and 4 to 36 cm/s (14 +/- 5), pulsatility index ranged between 0.4 to 2.8 (1.2 +/- 0.4). Transtemporal systolic and diastolic FVs ranged between 15 and 58 cm/s (33 +/- 9) and 4 to 25 cm/s (11 +/- 4). Transorbital and transtemporal FVs correlated significantly (p = 0.01). Our study demonstrates that transtemporal insonation of the proximal intracranial OA is feasible. Whenever OA assessment for analysis of collateral function is required, this simple approach, avoiding direct eye bulb insonation, should be considered.

Multiple brain abscesses following surgical treatment of a perianal abscess.

We report a case of multiple brain abscesses (BAs) in a 67-year-old man with symptoms of progredient disorientation and amnestic aphasia. Onset of symptoms occurred one week after surgical treatment of a perianal abscess. No other source of infection was identified and the abscesses were limited to the brain. The immune status was normal but a patent foramen ovale (pFO) was found. The patient was treated with high-dose antibiotics, leading to a complete radiological disappearance of the BAs. Hematogenous spread of infectious emboli from a perianal focus exclusively to the brain is very rare. In our patient, the mechanisms of infectious spread into the brain might have occurred via a cardiac right-to-left shunt or alternatively via the non-valvular vertebral venous system. In this manuscript, both pathways are critically reviewed.

Ultrasonographic measurement of cerebral blood flow, cerebral circulation time and cerebral blood volume in vascular and Alzheimer's dementia.

Vascular dementia (VD) and Alzheimer's dementia (AD) are the most common differential diagnoses in patients with cognitive impairment. Although of different etiology, small vessel disease is postulated to be present in both conditions. We investigated global cerebral blood flow (CBF), global cerebral circulation time (CCT) and global cerebral blood volume (CBV) in VD and AD patients using a multimodal ultrasound (US) approach. 20 VD and 20 AD patients were included and compared with 12 age-matched controls. Duplex US of both internal carotid and vertebral arteries was performed to measure CBF. CCT was defined as the time delay of an echo-contrast bolus arrival between the internal carotid artery and internal jugular vein using extracranial Doppler. CBV was calculated as the product of CBF and CCT. CBF was significantly lower (VD: 570 +/- 61; AD: 578 +/- 77; controls: 733 +/- 54 ml/min) and CCT significantly longer (8.8 +/- 2.6; 8.2 +/- 1.4; 6.4 +/- 0.8 s) in both patient groups compared with controls (p < 0.003). No difference in CBF and CCT was found between the two patient groups. CBV was similar in all three groups (82 +/- 20; 79 +/- 19; 78 +/- 9 ml). The equally reduced CBF and prolonged CCT in VD and AD support the hypothesis, that small vessel disease is a relevant factor in both types of dementia. The presented multimodal US approach helps to assess the extent of changes in the global cerebral hemodynamics in patients with dementia but does not allow a differentiation between VD and AD.

Left ventricular apical thrombus after systemic thrombolysis with recombinant tissue plasminogen activator in a patient with acute ischemic stroke.

BACKGROUND: Thrombolysis with recombinant tissue plasminogen activator (rtPA) is an established treatment in acute stroke. To prevent rethrombosis after rtPA therapy, secondary anticoagulation with heparin is commonly performed. However, the recommended time-point and extent of heparin treatment vary and are not well investigated. CASE PRESENTATION: We report a 61-year-old man who developed an acute global aphasia and right-sided hemiparesis. Cranial CT was normal and systemic thrombolytic therapy with tPA was started 120 minutes after symptom onset. Low-dose subcutaneous heparin treatment was initiated 24 hours later. Transthoracic echocardiography (TTE) 12 hours after admission showed slightly reduced left ventricular ejection fraction (LVEF) but was otherwise normal. 48 hours later the patient suddenly deteriorated with clinical signs of dyspnea and tachycardia. TTE revelead a large left ventricular apical thrombus as well as a reduction of LVEF to 20 %. Serial further TTE investigations demonstrated a complete resolution of the thrombus and normalisation of LVEF within two days. CONCLUSION: Our case demonstrates an intracardiac thrombus formation following rtPA treatment of acute stroke, probably caused by secondary hypercoagulability. Rethrombosis or new thrombus formation might be an underestimated complication of rtPA therapy and potentially explain cases of secondary stroke progression.

Delayed Transcranial Echo-Contrast Bolus Arrival in Unilateral Internal Carotid Artery Stenosis and Occlusion.

Some patients with internal carotid artery (ICA) occlusion or stenosis are at risk of developing a hemodynamic stroke. Transcranial ultrasonography using an echo-contrast bolus technique might be able to assess the extent of hemodynamic compromise. We describe a transcranial Doppler sonographic method that analyzes the differences in echo-contrast bolus arrival between both middle cerebral arteries after intravenous echo-contrast application. Ten patients with 50%-79% ICA stenosis, 10 patients with 80%-99% ICA stenosis and 22 patients with ICA occlusion were studied and compared with 15 age-matched controls. There were significant increases in delayed filling of the middle cerebral artery in both 80%-99% stenoses and occlusions compared with controls. The extent of the observed delays did not correlate with vasomotor reactivity. Echo-contrast bolus arrival time can be used to gain additional information on the intracranial hemodynamic effects of extracranial carotid artery disease that seems to be independent of the established ultrasound indices.

Ultrasonographic assessment of global cerebral blood volume in healthy adults.

The authors describe a new ultrasonographic method for analysis of global cerebral blood volume (CBV) and its application under controlled hyperventilation. CBV was determined as the product of global cerebral blood flow volume (CBF) and global cerebral circulation time. CBF was measured by duplex sonography and calculated as the sum of flow volumes in both internal carotid arteries and vertebral arteries. Extracranial Doppler assessed cerebral circulation time by determining the time interval of echo-contrast bolus arrival between internal carotid artery and contralateral internal jugular vein. Forty-four healthy volunteers (mean age 45 +/- 19 years, range 20-79 years) were studied. Mean CBV was 77 +/- 13 mL. CBV did not correlate with age, end-tidal carbon dioxide level, heart rate, or blood pressure. Hypocapnia was induced in 10 subjects by controlled hyperventilation. Mean reduction of end-tidal carbon dioxide values by 9 +/- 1 mm Hg led to a significant increase in cerebral circulation time (6.1 +/- 0.9 to 8.4 +/- 1.1 second, P < 0.0001) and a significant CBF decrease (742 +/- 85 to 526 +/- 77 mL/min, P < 0.0001), whereas CBV remained unchanged (75 +/- 6 to 73 +/- 10 mL).

Extrajugular pathways of human cerebral venous blood drainage assessed by duplex ultrasound.

Cerebral venous drainage in humans is thought to be ensured mainly via the internal jugular veins (IJVs). However, anatomic, angiographic, and ultrasound studies suggest that the vertebral venous system serves as an important alternative drainage route. We assessed venous blood volume flow in vertebral veins (VVs) and IJVs of 12 healthy volunteers using duplex ultrasound. Measurements were performed at rest and during a transient bilateral IJV and a circular neck compression. Total venous blood volume flow at rest was 766 +/- 226 ml/min (IJVs: 720 +/- 232, VVs: 47 +/- 33 ml/min). During bilateral IJV compression, VV flow increased to 128 +/- 64 ml/min. Circular neck compression, causing an additional deep cervical vein obstruction, led to a further rise in VV volume flow (186 +/- 70 ml/min). As the observed flow increase did not compensate for IJV flow cessation, other parts of the vertebral venous system, like the intraspinal epidural veins and the deep cervical veins, have to be considered as additional alternative drainage pathways.

Doppler sonographic evaluation of shunts in patients with dural arteriovenous fistulas.

BACKGROUND AND PURPOSE: Doppler sonography has been used to assess global cerebral circulation time (CCT) in healthy volunteers and a small number of patients with cerebral arteriovenous malformations. We evaluated the effect of arteriovenous shunts on global CCT in patients with dural arteriovenous fistulas (DAVFs) by using this Doppler echo contrast-bolus tracking test. METHODS: We measured CCT as the time delay in a contrast bolus to the internal carotid artery (ICA) and internal jugular vein (IJV) in 13 patients with DAVF and 30 age-matched control subjects. Mean CCT and mean arterial and venous rise times (Delta t = 80% of total signal-intensity increase) were compared. Posttreatment follow-up measurements were performed in five patients. RESULTS: Mean CCT and venous Delta t were significantly different between patients and controls (CCT, 1.1 +/- 0.9 vs 6.9 +/- 1.2 seconds, P <.0001; venous Delta t, 5.2 +/- 2.0 vs 7.0 +/- 2.6 seconds, P =.024), but arterial Delta t values were not (4.4 +/- 1.8 vs 4.7 +/- 2.0 seconds). Posttreatment follow-up of two occluded fistulas showed CCT normalization. One near-occlusion showed a two-step increase in signal intensity, and incomplete occlusion in two patients left the CCT unchanged. One patient with an extracranial, highly vascularized glomus tumor draining into the IJV had a CCT of 1.8 seconds. CONCLUSION: In DAVF patients, sonographic CCT is significantly shortened. Our test is highly sensitive for arteriovenous shunts but not specific for DAVF alone. Follow-up measurements in DAVF patients are well correlated with results of angiographic treatment. CCT assessment might become an additional tool for evaluating these patients and monitoring their treatment.

Multimodal ultrasound assessment of cerebral hemodynamics in a patient with a diffuse cerebral angiomatosis.

Recent newly developed ultrasound (US) techniques extend our ability to study the cerebral hemodynamics in patients with arteriovenous malformations (AVM) beyond the conventional cerebral blood flow velocity (CBFV) analysis. We present US data of global cerebral blood flow (CBF) and global cerebral circulation time (CCT) in a patient with a unique bihemispherial diffuse cerebral angiomatosis and compare them with 10 age-matched controls. In addition, the estimation of an US-derived global cerebral blood volume (CBV) is proposed. Duplex sonographic CBF analysis revealed 2620 mL/min in the patient and 754 +/- 93 mL/min in controls. Doppler sonographic CCT was 2.9 s and 6.3 +/- 1.5 s and CBV 126 mL and 79 +/- 19 mL, respectively. US allows a simple, minimal invasive bedside analysis of several global hemodynamic parameters that might provide valuable additional information in patients with diffusely altered cerebral hemodynamics.

Dopplersonographic measurement of global cerebral circulation time using echo contrast-enhanced ultrasound in normal individuals and patients with arteriovenous malformations.

Echo-contrast "bolus tracking" by ultrasound (US) is an exciting new tool to study cerebral haemodynamics. In the present study, a global cerebral circulation time (CCT) was measured by extracranial Doppler as the time difference of contrast bolus arrival between the internal carotid artery and internal jugular vein. A total of 64 healthy volunteers and 9 patients with an angiographically diagnosed arteriovenous malformation (AVM) were studied. CCT in volunteers and patients was calculated as the time interval between the points of 10% rise (CCT(1)) and 90% rise (CCT(3)) of the total intensity increase and between the turning points (CCT(2)) of the resulting time-intensity curves. In the volunteer group, CCT(1) was 5.4 +/- 1.8 s, CCT(2) was 7 +/- 1.3 s and CCT(3) 7.5 +/- 1.8 s. CCT results in the AVM group were 2.8 +/- 2.5 s, 3.0 +/- 1.3 s and 4.5 +/- 2.1 s, respectively, and differed significantly from the controls. For the first time, we could confirm a significant shortening of CCT in patients with cerebral AVM by US. The presented test might become a new, additional tool for AVM evaluation and follow-up of treatment in these patients.

Venous drainage patterns in a case of pseudotumor cerebri following unilateral radical neck dissection.

We report the extracranial venous ultrasound findings in a case of pseudotumor cerebri (PTC) following unilateral radical neck dissection (rND). PTC is known to be a rare complication following bilateral rND, and is caused by venous outflow obstruction. Single cases of PTC have been reported after unilateral rND, and are thought to be due to resection of the dominant internal jugular vein (IJV) in the presence of a hypoplastic or aplastic contralateral transverse sinus. Our patient developed PTC despite prominent flow in the contralateral IJV as shown by venous ultrasound. No compensatory increase in flow in the vertebral veins was observed, as confirmed by digital subtraction angiography. We conclude that the physiological collateral function of the vertebral venous system and deep neck veins was insufficient and contributed to global venous outflow obstruction in our case of unilateral rND.