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Purpose: To assess prospectively the agreement of magnetic resonance (MR) pulmonary perfusion with single-photon emission computed tomography (SPECT) perfusion for perfusion defects down to the subsegmental level in patients with suspected pulmonary embolism (PE)., Material and Methods: In 41 patients with suspected PE, contrast-enhanced MR pulmonary perfusion (3D-FLASH, TR/TE 1.6/0.6 ms) was compared to SPECT perfusion on a per-examination basis as well as at the lobar, segmental, and subsegmental level., Results: The MRI protocol was completed in all patients, and mean examination time was 3 min 56 s. MR perfusion showed a very high agreement with SPECT (kappa value per examination 0.98, and 0.98, 0.83, and 0.69 for lobar, segmental, and subsegmental perfusion defects, respectively). Of 15 patients with PE, MR perfusion detected 14 cases., Conclusion: The very high agreement of MR perfusion with SPECT perfusion enables the detection of subtle findings in suspected PE.

Serious postoperative psycho-neurological dysfunction is at least partially attributed to the occurrence of gaseous microbubbles in the arterial line of extracorporeal circulation (ECC). Therefore, we investigated in a prospective randomized double blind study whether the usage of dynamic bubble trap (DBT) will reduce microbubble load of patients undergoing aortic valve replacement. Patients (n = 41) were divided into group I (GI, n = 22) with DBT introduced into the arterial line of ECC and group II (GII, n = 19) with placebo-DBT instead. Doppler ultrasonography was used for detection of microbubbles before and after DBT, and for detection of high intensity transient signals (HITS) within the middle cerebral artery. The recording time during ECC was divided into period 1 (P1, until aortic clamp removal) and period 2 (P2, clamp removal until the end of ECC). A significant reduction of microbubble load was found in GI only (p < 0.0001 for ECC; p < 0.0001 for P1; p < 0.0025 for P2). A significant difference in number of HITS between the groups was observed in P1 only (p < 0.002 left middle cerebral artery, p < 0.005 right middle cerebral artery), since in P2 the trapped air in left chamber can go to the supraaortal vessels without passing ECC. In conclusion the use of DBT cannot substitute careful venting after aortic declamping. Nevertheless, reduction of HITS in the cross-clamped period of ECC justifies the use of DBT in patients undergoing open chamber surgery.

Background and Purpose: Ultrasound-accelerated thrombolysis is a promising approach toward acute stroke treatment. In previous in vitro studies, we demonstrated enhanced thrombus destruction induced by 20-kHz ultrasound. However, little is known about biological interactions of low-frequency ultrasound with brain tissue. The aim of this in vivo MRI study was to assess safety aspects of transcranial low-frequency ultrasound in rats., Methods: The cranium of 33 male Wistar rats was sonificated for 20 minutes (20-kHz continuous wave). Power output was varied between 0 and 2.6 W/cm2. Tympanal and rectal temperature was monitored. Diffusion-weighted imaging and T2-weighted imaging was performed before and 4 hours, 24 hours, and 5 days after sonification. Apparent diffusion coefficients (ADCs) and T2 relaxation time (T2-RT) were measured in regions of interest in the cortex and the basal ganglia. The animals were euthanized for histological evaluation thereafter., Results: Tympanal temperature increased significantly during insonation with 1.1 and 2.6 W/cm2. ADCs decreased significantly at 0.5 and 1.1 W/cm2, indicating cytotoxic edema. T2-RT increased significantly in the 0.5 and 1.1 W/cm2 group, consistent with vasogenic edema. No changes were detectable in the low-power output group (0.2 W/cm2). After sonification with 2.6 W/cm2, a significant loss of neurons could be detected on histopathology. Furthermore, 3 animals developed circumscript cortical lesions that could be identified as parenchymal necrosis., Conclusions: Low-frequency ultrasound caused vasogenic and cytotoxic brain edema and intracerebral necrosis in a dose-dependent fashion. This study indicates therapeutic low-frequency ultrasound as being potentially harmful and underlines the necessity of careful evaluation in further animal models.

Purpose: To retrospectively assess the indication for thoracic real-time MRI, demonstrate typical findings, analyze the diagnostic potential in subgroups with suspected pulmonary embolism (PE) and aortic dissection (AD), and describe the influence of real-time MRI on the role of MRI in acute thoracic diseases., Materials and Methods: From July 2001 to February 2005, real-time MRI was applied in 2,256 examinations in 1,714 patients. MRI was the primary diagnostic modality for these thoracic diseases as computed tomography has been available only since 2003. Characteristics of the TrueFISP sequence applied were: TR/TE/flip angle 3.1 ms/1.6 ms/59 degrees , respectively. FOV 340 - 360 mm, matrix size 156 to 192 x 256 pixels, slice thickness 3 to 4 mm, slices overlapped by 50 %. Acquisition time was 0.4 to 0.5 s per image. Three hundred and twenty transverse, coronal and sagittal images were acquired in three minutes. No breath holding, and only minimal patient cooperation, was required. Turbo-spin-echo sequences as well as ECG-gated and contrast-enhanced sequences were added depending on the indication., Results: Most common indications were: acute thoracic nonspecified disease (n = 276, 12.24 %), PE (n = 573, 25.4 %), bleeding (n = 154, 6.8 %), AD (n = 222, 9.8 %), topographic information in complex findings (n = 654, 29.0 %). Real-time MRI was the sole MRI technique applied in 180 examinations (8.0 %), ECG-gated real-time MRI was applied in 87 examinations and breath hold was used in 107 examinations. PE was diagnosed in 181 examinations; reference techniques (MRI, computed tomography, single photon emission computed tomography) confirmed 170 of these and detected 19 more cases (sensitivity 90.0 %, specificity 97.1 %). Real-time MRI detected 141 suspected AD and 53 more nonsuspected AD. Of these, 191 were confirmed by other MRI techniques, surgery or clinical course (98.5 %). Real-time MRI coincidentally detected 56 pulmonary tumors, all were confirmed with computed tomography. Thus, especially vascular diseases could be easily assessed with real-time MRI, while computed tomography had advantages in the evaluation of the lung parenchyma., Conclusion: Real-time MRI both enables emergency MRI examinations for thoracic diseases in clinical patients in unstable condition and allows an explorative style of working in patients with nondefined acute thoracic diseases.

Tha aim of this study was to demonstrate the feasibility of MRI for short-term follow-up examinations in patients with acute pulmonary embolism (PE), and to assess temporal changes of pulmonary perfusion and thrombus characteristics that may be helpful in determining thrombus age. Thirty-three patients (15 female, 18 male, mean age 59.4 years) with acute PE were examined initially and 1 week later using both 16-row computed tomography (CT) and MRI with magnetic resonance angiography (MRA), real-time MRI and magnetic resonance (MR) pulmonary perfusion imaging. MRA and MR pulmonary perfusion used contrast-enhanced 3D flash sequences, and real-time MRI used true fast imaging with steady-state precession sequences (repetition time/echo time 3.1/1.5, bandwidth 975 Hz, 256 matrix size, acquisition time 0.4 s per image) in three orthogonal planes. Follow-up examinations were feasible for all patients. Diagnosis of PE was concordant between MRI and CT in all patients. The signal intensity of embolic material increased after 1 week for real-time MRI [132+/-5 vs. 232+/-22 (standard error of the mean), p<0.001], but not significantly for MRA. MR pulmonary perfusion of areas affected by PE increased (area under the curve initially 9.6+/-7.4, at follow-up 40.7+/-7.6, p<0.001). A decreasing time-to-peak in normal lung areas (15.7+/-0.96 and 13.2+/-0.55, respectively, p<0.05) indicated systemic circulatory effects of PE, and subsiding pulmonary artery obstruction improved arterial inflow for the entire lung. Follow-up examinations of patients with acute PE are feasible with MRI, and a relation between thrombus appearance and thrombus age can be implied.

Objective: The causes of cerebral sinus and vein occlusion and the accompanying parenchymal changes remain largely unexplained. The clinical variability and low incidence of the disease complicate systematic clinical investigations. Animal studies are indispensable; however, existing animal models of sinus thrombosis do not allow for long-term follow-up studies and are not suitable for pharmacological recanalization because sinus thrombosis is induced by ligation and injection of thrombogenic substances and does not resemble sinus thrombosis in humans., Methods: We induced thrombosis of the superior sagittal sinus (SSS) by careful topical application of ferric chloride onto the SSS of rats, leading to highly reproducible occlusions. Magnetic resonance imaging was performed immediately after initiation of thrombosis and on postoperative Days 1, 2, and 7. Diffusion- and T2-weighted images allowed for calculation of the apparent diffusion coefficient and T2 relaxation time. Vascular status was assessed by venous magnetic resonance angiography. Neurological deficits were assessed with the rotarod test., Results: Seven days after induction of thrombosis, partial recanalization (50.7% of the SSS remaining occluded) was accompanied by a resolution of early generalized changes of the apparent diffusion coefficient and of T2 relaxation time, indicating edema of the entire brain parenchyma. Compared with sham-treated animals, clinical skills in the experimental group improved over time, which was statistically independent from the degree of recanalization. Histopathological analysis revealed no signs of cerebral infarction., Conclusion: This is the first animal model of SSS thrombosis that offers the possibility to investigate pathophysiological aspects of the disease as well as the influence of therapy on the nature of disease progression.

Background: Based on a newly developed model of reversible superior sagittal sinus (SSS) thrombosis in the rat, we investigated the effect of thrombolytic and anticoagulant treatment on recanalization, brain parenchymal changes, and motor deficits., Methods: Thrombosis of the SSS was induced by topical application of ferric chloride. Occlusion was confirmed by magnetic resonance angiography (MRA). Six hours after operation, single treatment with 10 mg recombinant tissue plasminogen activator (rtPA)/kg and 6 mg abciximab/kg or subcutaneous injection of 450 IU/kg enoxaparin twice daily was started, each group containing 10 rats. Follow-up MRI with T2- and diffusion-weighted images was performed on the first, second, and seventh postoperative day., Results: Control and enoxaparin-treated animals developed diffuse brain edema without infarction or intracerebral bleeding. This was indicated by an increase of T2 relaxation time and a decrease of the apparent diffusion coefficient in the parasagittal and lateral cortex. In these groups, the degree of recanalization after 7 days was comparable (48% versus 52%). Enoxaparin-treated animals showed significant amelioration of functional deficits. Clinical outcome was best in the abciximab-treated group, with a residual sinus occlusion of 36% after 1 week. Highest recanalization was achieved by lysis with rtPA (85%)., Conclusions: Enoxaparin treatment in rats with cerebral venous thrombosis significantly influences clinical outcome. However, it has no effect on recanalization. GPIIb/IIIa antagonists and rtPA accelerate thrombolysis. They may represent an alternative in treatment of cerebral venous thrombosis.

Background and Purpose: Although rare, cerebral venous thrombosis (CVT) is being diagnosed more frequently owing to improved imaging techniques. The venous infarcts caused by CVT in 50% of patients are largely reversible and differ from arterial stroke. Our purpose was to study the time-dependent changes of venous infarcts on MR images and to define the variables that influence lesion volume in humans., Methods: MR images and venous angiograms were evaluated in 15 consecutive patients with venous infarcts due to CVT of sinus, cortical, or internal veins. All patients were treated with intravenous dose-adjusted heparin followed by oral anticoagulation for 12 months. Reduction of signal intensity changes on T1- and T2-weighted images was correlated to the degree of recanalization, age, initial absolute lesion size, and hemorrhage., Results: Within the first 30 days, we found a significant correlation between the volume of the lesion on T1-weighted images and recanalization. However, early recanalization did not influence the final lesion volume after 12 months. Eleven patients showed complete resolution of changes on T1- and T2-weighted images. Age of the patients influenced initial absolute volume of brain damage., Conclusion: In venous stroke, even large parenchymal changes can resolve completely independent from recanalization of the thrombosed veins and sinuses. A plausible hypothesis is that venous infarcts largely consist of a persistent edema and that the lesion volume is influenced by the development of collateral veins. However, further investigations are necessary to understand the underlying abnormal mechanisms.

Background: There is insufficient data on short- and especially long-term prognosis of cerebral venous thrombosis (CVT)., Methods: In 79 consecutive patients, we analyzed factors for acute death and functional outcome at hospital discharge and after 6 months as well as long-term prognosis >/=12 months. Neurological deficits were graded on the National Institute of Health Stroke Scale (NIHSS), functional outcome on the modified Rankin Scale (mRS). Primary outcome was defined as mRS >/= 3 at 6 months, secondary outcomes were death during hospital treatment and number as well as type of complications during follow-up >/=12 months after hospital discharge. Forty-two patients were recruited prospectively, 37 were identified by chart review. Information on outcome was based on neurological examinations at our outpatient clinic., Results: Factors significantly related to acute death were age, the NIHSS on admission, more than two seizures despite antiepileptic treatment, venous infarct, and hemorrhagic transformation of the venous infarct. Primary outcome after 6 months in 74 patients was excellent with 73% of patients reaching a mRS 0-1, 4% a mRS of 2, and 23% a mRS 3-6, including 12 deaths in the acute stage of illness. Factors significantly related to a mRS >/= 3 at 6 months in a logistic regression analysis were age and items 1a-c of the NIHSS on admission related to consciousness. Fifty-eight surviving patients had a follow-up >/= 12 months (median: 31; mean: 52 +/- 61 months). Most frequent complication on long-term follow-up was epilepsy in nine patients and recurrent venous thrombosis in seven patients., Conclusions: When the acute stage of illness has been survived, CVT has a good prognosis unlike arterial ischemic stroke.

Background and Purpose: Investigating focal cerebral ischemia requires animal models that are relevant to human stroke. Complications and side effects are common among these models. The present study describes potential pitfalls in 3 techniques for middle cerebral artery occlusion (MCAO) in rats using magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA)., Methods: Rats were subjected to temporary MCAO for 90 minutes using the suture technique (group I; n=10) or to permanent MCAO using the suture technique (group II; n=10) or the macrosphere technique (group III; n=10). Clinical evaluation was performed after 3 hours and 24 hours. After 24 hours, animals underwent MRI and MRA to determine lesion size and the intracranial vascular status., Results: Hemispheric lesion volume was significantly smaller in group I (14.6%) compared with groups II (35.2%; P<0.01) and III (21.3%; P<0.05). Two animals (1 each in group II and III) did not demonstrate neurological deficits and had no lesion on MRI and a patent MCA main stem on MRA. Subarachnoid hemorrhage was detected in 2 animals (1 each in group I and II). MRA indicated a patent MCA main stem in 2 animals (group II), although both rats displayed neurological deficits. Hypothalamic infarction with subsequent pathological hyperthermia was detected in all animals in group II and in 1 rat in group III., Conclusions: Model failures occurred frequently in all groups. MRI and MRA helps to identify animals that need to be excluded from experimental stroke studies.

Cerebral venous thrombosis (CVT) associated with minor or trivial head trauma has only been described in a few cases so far. We report two patients who developed CVT after a sudden intracranial pressure increase and head acceleration. A 49-year-old woman jumped from a small rock, 1 m in height, and developed instantaneous occipital headaches. Magnetic resonance imaging (MRI) confirmed confluens sinuum thrombosis. Risk factors consisted of smoking and oral contraceptives. Our second patient, an 18-year-old woman, experienced instantaneous headaches after a sneezing attack. Superior sagittal and right-sided transverse sinus thrombosis were confirmed by venous computed tomography angiography. She took oral contraceptives as an additional risk factor. In about 20% of CVT cases the cause remains unclear. As minor head trauma may not have been recognized during history taking, this may represent a so far under-recognized precipitating factor for CVT.

The feasibility and diagnostic value of real-time magnetic resonance imaging (RT-MRI) for the diagnosis of acute pulmonary embolism (PE) was evaluated by comparing RT-MRI and magnetic resonance angiography (MRA). In 39 consecutive patients with suspected PE real-time true fast imaging with steady-state precession (TrueFisp) was prospectively compared with contrast-enhanced MRA on a 1.5-T MR scanner. The TrueFisp sequence used allowed acquisition of T2-weighted images at 0.4 s per image so that the pulmonary vasculature could be visualized in three orientations in <3 min without the need for breath holding or contrast media application. Results of additional scintigraphic pulmonary perfusion examinations were available from 17 patients. All 39 primary RT examinations (100%) and 30 of 39 MRA examinations (77%) were of diagnostic quality. The reasons underlying failure to achieve diagnostic quality for MRA were breathing artifacts among dyspneic patients in all 9 cases. Compared with MRA, the sensitivities and specificities of RT sequences for PE were 93 and 100% (per examination), 96 and 100% (lobar artery PE), and 97 and 100% (segmental artery PE), respectively. Compared with scintigraphy, the sensitivity and specificity of RT-MRI were 83 and 100%, respectively. The MRA reached 100% sensitivity and specificity in this subgroup. The RT-MRI proved to be very robust and undisturbed by respiratory movements and patient cooperation. Its image quality assured fast diagnostic examinations, and its sensitivity and specificity, compared with MRA and scintigraphy, were sufficient to allow the diagnosis of acute central, lobar, and segmental PE; therefore, the emergency diagnosis of PE using RT-MRI is feasible and reliable.

Background and Purpose: Cardiac surgery carries a high risk of neurological complications; therefore, these patients would be an appropriate target population for neuroprotective strategies. In this study, we evaluated postoperative diffusion-weighted imaging (DWI) as a potential surrogate marker for brain embolism and its relationship to neurobiochemical markers of brain injury., Methods: Of a total of 45 consecutive patients undergoing aortic valve replacement, 37 completed preoperative and postoperative MRI. At the time of the MRI studies, serum S100beta and neuron-specific enolase concentrations were determined. Preexisting T2 and postoperative DWI lesion volumes were quantified. All patients had a blinded neurological examination before and after operation., Results: New perioperative DWI lesions were present in 14 patients (38%), of whom only 3 developed focal neurological deficits. Eighteen small lesions were found in the white matter or vascular border zones in all but 2 patients with territorial stroke. The appearance of new DWI lesions correlated with age, pre-existing T2 lesion volume, and postoperative S100beta concentrations on days 2 to 4 after surgery. In a forward stepwise canonical discrimination model, only T2 lesion volume was selected as a relevant variable., Conclusions: The incidence of postoperative DWI lesions in aortic valve replacement is high, and a suitable marker for neuroprotective trials would be a reduction in the number of such lesions. The volume of preexisting T2 lesions is related to the development of perioperative DWI lesions.

Background and Purpose: Brain edema is a life-threatening consequence of stroke and leads to an extension of the affected tissue. The space-occupying effect due to brain edema can be quantified in rat stroke models with the use of MRI. The present study was performed to test 2 hypotheses: (1) Can quantification of the space-occupying effect due to brain edema serve as a noninvasive measure for brain water content? (2) Does morphometric assessment of brain swelling allow determination of true infarct size on MRI after correction for the space-occupying effect of edema?, Methods: Thirty rats were subjected to permanent suture middle cerebral artery occlusion. MRI was performed after 6 or 24 hours, and hemispheric swelling was assessed morphometrically. Interobserver and intraobserver agreements were determined for MRI measurements. In study I, the space-occupying effect due to brain edema was correlated with the absolute brain water content by the wet/dry method. In study II, lesion volumes corrected and uncorrected for edema were calculated on MRI and on TTC staining and compared., Results: Interobserver and intraobserver agreements for MRI measurements were excellent (r>or=0.97). Brain water content and hemispheric swelling correlated well after 6 and 24 hours (r>or=0.95). Corrected lesion volumes correlated with r=0.78 between TTC staining and MRI. Without edema correction, lesion volumes were overestimated by 20.3% after 6 hours and by 29.6% after 24 hours of ischemia., Conclusions: Morphometric assessment of hemispheric swelling on MRI can determine the increase in absolute brain water content noninvasively and can also provide ischemic lesion volumes corrected for brain edema.

Background and Purpose: Recanalization in dural sinus thrombosis (DST) has been observed previously; however, systematic prospective data are lacking. The influence of recanalization on DST outcome has not yet been thoroughly evaluated., Methods: Thirty-seven consecutive patients with DST were prospectively examined. Neurological deficits were graded with the National Institutes of Health Stroke Scale (NIHSS) on hospital admission and discharge. Functional outcome was assessed with the modified Rankin Scale (mRS) on hospital discharge and after 12 months. All patients were treated with intravenous heparin in the acute stage of illness, followed by oral anticoagulation for 12 months. Imaging follow-up with MR angiography and, in a few cases, with CT or conventional angiography was performed on hospital discharge and after 6 and 12 months., Results: Twelve-month functional outcome was excellent in 89% of patients with an mRS of 0 or 1. A recanalization rate of 60% was already observed on hospital discharge (22+/-6 days); thereafter, recanalization rates increased insignificantly. Early recanalization was not related to NIHSS score on hospital discharge or an mRS of 0 on discharge or after 12 months., Conclusions: We found a high frequency of early recanalization but without influence on clinical outcome parameters. Frequent imaging follow-ups in DST are not useful because they provide no information on patient outcome.

Magnetic resonance imaging (MRI) provides insights into the dynamics of focal cerebral ischemia. Usually, experimental stroke is induced outside the magnet bore, preventing investigators from acquiring pre-ischemic images for later pixel-by-pixel comparisons and from studying the earliest changes in the hyperacute phase of ischemia. Herein, we introduce a new and easy to apply in-bore occlusion protocol based on the intraarterial embolization of ceramic macrospheres. PE-50 tubing, filled with saline and six macrospheres (0.315-0.355 mm in diameter), was placed into the internal carotid artery (ICA) of anesthetized Sprague-Dawley rats. The animals were transferred into an MRI scanner (7.0 T) and baseline diffusion-weighted imaging (DWI) and T2-imaging was performed. Then the macrospheres were injected into the internal artery to occlude the MCA. Post-ischemic DWI and T2-imaging was started immediately thereafter. The apparent diffusion coefficient (ADC) (a marker for cytotoxic brain edema) and T2-relaxation time (a marker for vasogenic brain edema) were determined in the ischemic lesions and compared to the unaffected hemisphere. ADC significantly declined within the first 5-10 min after stroke onset. T2-relaxation time increased as early as at the first T2-imaging time-point (20-35 min after embolization). After 150 min of ischemia, the lesions covered 18.0 +/- 7.4% of the hemispheres. The model failed in one out of nine animals (11%). This model allows MR-imaging from the initial minutes after permanent middle cerebral artery (MCA) occlusion. It does not permit reperfusion. This technique might provide information about the pathophysiological processes in the hyperacute phase of stroke.

Background and Objectives: During transmyocardial laser revascularization (TMLR), multiple microembolic signals (MES) can be detected in cerebral arteries. We sought to characterize composition and clinical relevance of these MES and to evaluate strategies to reduce cerebral microembolization during TMLR., Study Design/materials and Methods: TMLR was performed in pigs. Laser energy was set to 4-10 J (group A) or 80 J (group B). Oxygen concentration was varied between 21 and 100%. MES were recorded in the ophthalmic artery. Brain and spinal cord were investigated histologically after 10 days., Results: More MES could be detected during high- compared to low-energy laser procedures. Ventilation with 100% oxygen reduced the number of MES. No lesions were found on histology., Conclusions: The number of MES depends on the laser energy. Laser-induces cavitation-effects lead to an additional release of nitrogen bubbles. Thus, the microembolic load can be reduced by ventilation with 100% oxygen and by decreasing the laser energy., (Copyright 2004 Wiley-Liss, Inc.)

Background: Recent studies suggest that healthy sport divers may develop clinically silent brain damage, based on the association between a finding of multiple brain lesions on MRI and the presence of right-to-left shunt, a pathway for venous gas bubbles to enter the arterial system., Methods: We performed echocontrast transcranial Doppler sonography in 42 sport divers to determine the presence of a right-to-left shunt. Cranial MRI was carried out using a 1.5 T magnet. A lesion was counted if it was hyperintense on both T2-weighted and T2-weighted fluid attenuated inversion recovery sequences. To test the hypothesis that the occurrence of postdive arterial gas emboli is related to brain lesions on MRI, we measured postdive intravascular bubbles in a subset of 15 divers 30 min after open water scuba dives., Results: Echocontrast transcranial Doppler sonography revealed a right-to-left shunt in 16 of the divers (38%). Only one hyperintensive lesion of the central white matter was found and that was in a diver with no evidence of a right-to-left shunt. Postdive arterial gas emboli were detected in 3 out of 15 divers; they had a right-to-left shunt, but no pathologic findings on cranial magnetic resonance imaging., Conclusions: Our data support the theory that right-to-left shunts can serve as a pathway for venous gas bubbles into the arterial circulation. However, we could not confirm an association between brain lesions and the presence of a right-to-left shunt in sport divers.

Background and Purpose: Permanent middle cerebral artery occlusion (MCAO) with the use of the suture technique causes hypothalamic damage with subsequent hyperthermia, which can confound neuroprotective drug studies. In the present study the neuroprotective effects of dizocilpine (MK-801) were compared in different permanent MCAO models with and without hypothalamic damage and hyperthermia., Methods: Sixty Sprague-Dawley rats were treated with MK-801 or placebo, beginning 15 minutes before MCAO, and assigned to the following groups: suture MCAO (group I), macrosphere MCAO without hypothalamic damage (group II), or macrosphere MCAO with intentionally induced hypothalamic infarction (group III). Body temperature was measured at 3, 6, and 24 hours. Lesion size was determined after 24 hours (2,3,5-triphenyltetrazolium chloride staining)., Results: Hypothalamic damage was present in animals in group I and was intentionally induced in group III with the use of a modified macrosphere MCAO technique. Body temperature was significantly increased 3, 6, and 24 hours after MCAO in these 2 groups of animals. Hypothalamic damage and subsequent hyperthermia could be avoided effectively by limiting the number of macrospheres (group II). MK-801 provided a highly significant neuroprotective effect in group II but not in groups I and III., Conclusions: Hypothalamic damage with subsequent hyperthermia masked the neuroprotective effect of MK-801. This side effect can be avoided by using the macrosphere MCAO technique with a limited number of spheres. This model therefore may be more appropriate to study the effects of neuroprotective drugs in permanent focal cerebral ischemia than the suture method.

Transmyocardial laser revascularization (TMLR) is known to induce cerebral microembolic signals (MES). We quantified laser induced MES in patients undergoing TMLR during cardiopulmonary bypass for coronary artery bypass grafting (group A) and during TMLR treatment alone (group B). The total number of MES during a single laser application with identical energy was significantly higher in group A compared to group B (P<0.001). Also the peak of MES occurred significantly later in group A (P<0.0001). An increase of laser energy was associated with an increase in numbers of MES particular in group B (r=0.641). Different TMLR modalities generate different amounts of cerebral microembolic signals. Thus, adjustment of TMLR to these modalities may reduce potentially harmful cerebral microemboli and warrants further evaluation.

Background and Purpose: The suture middle cerebral artery occlusion (MCAO) model is widely used for the simulation of focal cerebral ischemia in rats. This technique causes hypothalamic injury resulting in hyperthermia, which can worsen outcome and obscure neuroprotective effects. Herein, we introduce a new MCAO model that avoids these disadvantages., Methods: Permanent MCAO was performed by intraarterial embolization using six TiO(2) macrospheres (0.3-0.4 mm in diameter) or by the suture occlusion technique. Body temperature was monitored, functional and histologic outcome was assessed after 24 h. Additional 16 rats were subjected to macrosphere or suture MCAO. Lesion progression was evaluated using magnetic resonance imaging (MRI)., Results: The animals subjected to suture MCAO developed hyperthermia (>39 degrees C), while the temperature remained normal in the macrosphere MCAO group. Infarct size, functional outcome and model failure rate were not significantly different between the groups. Lesion size on MRI increased within the first 90 min and remained unchanged thereafter in both groups., Conclusions: The macrosphere MCAO model provides reproducible focal cerebral ischemia, similar to the established suture technique, but avoids hypothalamic damage and hyperthermia. This model, therefore, may be more appropriate for the preclinical evaluation of neuroprotective therapies and can also be used for stroke studies under difficult conditions, e.g., in awake animals or inside the MRI scanner.

Objectives: To evaluate in a prospective multicentre setting the feasibility of transcranial colour coded duplex sonography (TCCS) for examination of the middle cerebral artery (MCA) in patients with acute hemispheric stroke, and to assess the validity of sonographic findings in a subgroup of patients who also had a correlative angiographic examination., Methods: TCCS was performed in 58 consecutive patients within six hours of the onset of a moderate to severe hemispheric stroke. Ultrasound contrast agent (Levovist) was applied if necessary. Thirty two patients also had computed tomography angiography (n=13), magnetic resonance angiography (n=18), or digital subtraction angiography (n=1). In 14 of these patients, both the sonographic and corresponding angiographic examination were performed within six hours of stroke onset (mean time difference between TCCS and angiography 0.8 hours). Eighteen patients, in whom angiography was carried out more than 24 hours after stroke onset, had a follow up TCCS for method comparison (mean time difference 6.1 hours)., Results: Initial unenhanced TCCS performed 3.4 (SD 1.2) hours after the onset of symptoms depicted the symptomatic MCA mainstem in 32 patients (55%) (13 occlusions, one stenosis, 18 patent arteries). After signal enhancement, MCA status could be determined in 54 patients (93%) (p<0.05), showing an occlusion in 25, a stenosis in two, and a patent artery in 27 patients. In 31 of the 32 patients who had correlative angiography, TCCS and angiography produced the same diagnosis of the symptomatic MCA (10 occlusions, three stenoses, 18 patent arteries); TCCS was inconclusive in the remaining one., Conclusion: TCCS is a feasible, fast, and valid non-invasive bedside method for evaluating the MCA in an acute stroke setting, particularly when contrast enhancement is applied. It may be a valuable and cost effective alternative to computed tomography and magnetic resonance angiography in future stroke trials.

Background: In recent studies, coma, cerebral hemorrhage, older age, and infectious origin have been identified as prognostic factors in cerebral venous thrombosis (CVT). However, no studies of the prognosis of CVT have evaluated hemodynamic factors. However, it is conceivable that the presence or absence and the efficiency of venous collaterals, as well as recanalization, may have an impact on brain tissue damage and hence on the prognosis of acute CVT., Methods: Twenty-six patients with acute CVT (mean age, 40+/-15 years) were recruited prospectively. All patients were treated with intravenous heparin, followed by oral anticoagulation for 12 months, except for 2 patients who were lost to follow-up after hospital discharge. Neurological deficits were graded on the National Institute of Health Stroke Scale on admission, at hospital discharge, and at 90+/-14 days after admission. The functional clinical outcome was graded on the modified Rankin Scale on day 90 after admission. All patients received a venous transcranial duplex sonography (TCCS) on admission and were followed up in case of a pathological result until normalization was recorded (mean follow-up, 316+/-395 days; range, 13 to 1180 days)., Results: Initial TCCS was pathological in 18 of 26 patients (69%). Four distinct venous drainage types were identified: increased drainage to the cavernous sinus and to the deep cerebral veins, flow reversal in the basal veins, and either compensatory increased or reversed flow in the transverse sinus. Initially normal venous TCCS or normalized TCCS within 90 days was significantly related to favorable outcome., Conclusions: TCCS can be used to evaluate venous drainage patterns in acute CVT. Furthermore, initially normal and normalization of initially pathological venous TCCS within 90 days is related to a favorable outcome in this disease.

Background: The purpose of this study was to determine whether microembolic signals (MES) occur after valve-sparing operations on the aortic root. One of the advantages of these procedures relates to the freedom of macroemboli without anticoagulation. Whether this holds true for circulating microemboli has not yet been verified., Methods: For comparison, 8 male patients (mean age: 51.8 +/- 12.8 years) were investigated 20.5 +/- 8.4 months after implantation of a mechanical composite graft (group I) and 9 female and 7 male patients (mean age 55.0 +/- 13.4 years) 23.5 +/- 20.0 months after valve-sparing replacement of the aortic root (group II). The middle cerebral artery was insonated for 2 periods of 30 min, breathing room air or O 2 at 9 l/min., Result: Breathing room air, the amount of MES was considerably smaller in group II (0.94 +/- 1.95 vs. 56.1 +/- 58.9 per 30 min, p = 0.006). The difference was less pronounced (0.5 +/- 1.3 vs. 28.9 +/- 42.6 per 30 min, p = 0.009) breathing oxygen. Breathing oxygen reduced MES significantly in group I (p < 0.05) but not in group II (p > 0.05)., Conclusions: Aortic valve-sparing operations induce MES at a significantly lower rate than composite aortic valve replacement using a mechanical valve.

Background and Purpose: The diagnostic yield of vertebrobasilar transcranial color-coded duplex ultrasonography (US) is often hampered by insufficient acoustic penetration, anatomic variations, and vessel tortousity. The purpose of this study was to evaluate the effect of echo enhancement on vertebrobasilar transcranial color-coded duplex US., Methods: In 23 consecutive patients (mean age, 61.0 +/- 11.1 years) with vertebrobasilar stroke, the vertebrobasilar system (P1 segment of the posterior cerebral artery [PCA], basilar head, V4 segment of the vertebral artery, and basilar artery) was examined with transcranial color-coded duplex US before and after injection of an echo-enhancer. The acoustic window was graded according to visibility of parenchymal structures, and vessel imaging was graded according to the appearance of the color mode signal. Maximum depth of the basilar color signal was recorded. All patients with an abnormal or inconclusive US finding underwent either digital subtraction angiography or MR angiography., Results: In the P1 PCA, V4 vertebral artery, basilar artery, and basilar head, image quality was insufficient in 65%, 82%, 83%, and 38%, respectively, before echo enhancement, and in 15%, 30%, 35%, and 9%, respectively, after echo enhancement. In all graded vessels, the improved image quality with echo enhancement was statistically significant. Compared with the reference examinations in the 15 cases of occlusion or stenosis, definite diagnosis was possible in 60% (nine cases) with nonenhanced transcranial color-coded duplex US and in 93% of (14 cases) after echo enhancement., Conclusion: Echo enhancement resulted in improved image quality of the vertebrobasilar system and markedly increased diagnostic confidence.

Background and Purpose: The insonation of the posterior communicating artery (PcomA) is often hampered by the unfavorable insonation angle when the temporal acoustic bone window (TBW) is used. This problem may be ameliorated by a lateral frontal bone window (LFBW). This study evaluated the TBW and LFBW for the assessment of collateral intracranial flow conditions and aimed at defining diagnostic transcranial color-coded duplex sonography (TCCS) criteria that do not need compression maneuvers., Methods: The A1 segment of the anterior cerebral artery (ACA), the PcomA, and the P1 segment of the posterior cerebral artery (PCA) were insonated by TCCS in 40 controls and 20 patients (16 internal carotid artery [ICA] occlusions or high grade stenoses, 3 middle cerebral artery stenoses or occlusions, 1 PCA stenosis)., Results: Detection rates for the A1 ACA and P1 PCA were higher for the TBW (94%, 98%) compared to the LFBW (86%, 81%) in controls. The PcomA was identified more frequently through the LFBW (86%) compared to the TBW (80%). Through the LFBW angle, corrected flow velocity (FV) measurements were possible for the PcomA with an average correction of 6.5 degrees. In controls, in > 80% of identified PcomAs, flow was directed towards the ICA. Side to side differences were below 7% for peak systolic FVs. In the patients with ICA disease, a flow reversal in the ipsilateral A1 ACA and a FV difference of > 30% seemed feasible for diagnosis of anterior communicating artery crossflow. Criteria for PcomA crossflow were side differences of FVs in the PcomA of > or = 30% and in the P1 PCA of > or = 20%., Conclusions: The LFBW proved useful as a complementary insonation plane to assess intracranial crossflow conditions, especially via the PcomA. We were able to define TCCS criteria for functional relevant collateralization without the need of compression maneuvers.

Background and Purpose: Cerebral venous pressure is governed by intracranial pressure, cerebral perfusion pressure, and venous outflow resistance. Therefore, changes in venous flow velocities are to be expected because of changes in intracranial pressure and brain tissue dislocation in patients with ischemic stroke and space-occupying brain edema., Methods: In 21 prospectively recruited patients with middle cerebral artery stroke and postischemic edema, flow velocities in the basal veins, the vein of Galen, the straight sinus, and the P2 segment of the posterior cerebral artery were recorded every 0.9+/-0.5 days during the first 5 days after symptom onset with the use of transcranial color-coded duplex sonography. The midline shift of the third ventricle was determined by B-mode imaging., Results: We observed an initial increase of flow velocity in the basal vein ipsilateral to the lesion, followed by a significant decrease within 5 days after symptom onset and with increasing midline shift in patients with brain herniation. In the straight sinus, flow velocity showed a biphasic U-shaped response to increasing dislocation of the third ventricle, with an initial decrease followed by an increase in the course of mass movement (midline shift 1 to 1.5 cm). A steep increase of flow velocity in the vein of Galen took place with a midline shift >1.5 cm. In the survivors these changes could not be observed. Flow velocity in the P2 segment of the posterior cerebral artery followed a typical course in neither the fatal cases nor the survivors., Conclusions: Monitoring of flow velocities in the basal cerebral veins and in the straight sinus can provide additional pathophysiological information in patients with space-occupying brain edema after acute stroke.

Background and Purpose: Initially decreased apparent diffusion coefficient (ADC) values are reversible if reperfusion is rapidly performed after focal brain ischemia. We sought to determine if reperfusion-induced renormalization of initially abnormal values indicates reversal of cellular, morphologic changes that occur during acute ischemia., Methods: Eighteen rats underwent 30 minutes of middle cerebral artery occlusion (MCAO) without reperfusion (group A, n = 6), with 1.5 hours of reperfusion (group B, n = 6), or with 12 hours of reperfusion (group C, n = 6). Diffusion- and perfusion-weighted MR images were obtained at the end of MCAO and 1.5 and 12 hours after reperfusion. Immediately after the final MR study, the brains were fixed by cardiac perfusion with 4% paraformaldehyde. Neuronal injury was evaluated on hematoxylin-eosin-stained slices, and astrocytic size was determined by the area of glial fibrillary acidic protein (GFAP) plus S-100 expression., Results: In group A in which ADC values decreased significantly, 47 +/-12% of the neurons were slightly shrunken; astrocytes were moderately swollen, and the area expressing GFAP plus S-100 was larger than that in the contralateral hemisphere (117 microm(2) +/- 6 vs 89 microm(2) +/- 2; P <.001). In group B in which ADC had renormalized, most neurons were moderately shrunken, and the frequency of such neurons was greater in group B (92% +/- 2) than in group A (P <.001); astrocytes were markedly swollen, and the area was larger than that in the contralateral hemisphere (123 microm(2) +/- 8 vs 85 microm(2) +/- 4, P <.001). In group C in which a secondary ADC decrease occurred, most neurons (94% +/- 3) were severely shrunken, and some had eosinophilic cytoplasm; astrocytes were disintegrated, and the area of GFAP plus S-100 expression was reduced (78 microm(2) +/- 4 vs 90 microm(2) +/- 5, P <.001)., Conclusion: Reperfusion-induced acute renormalization of ADC values is not associated with the reversal of neuronal shrinkage and astrocytic swelling that occur during ischemia. Conversely, the morphologic changes of astrocytes and neurons progressively worsen over time, although ADC values show a biphasic change.

Background and Purpose: Venous transcranial color-coded duplex sonography is a new technique for noninvasive evaluation of the intracranial venous system. However, the interobserver and intraobserver reliability of this method is unclear., Methods: In 23 healthy volunteers (30 +/- 7.3 years of age), the deep middle cerebral vein (dMCV), basal vein (BV), vein of Galen (VG), and straight (SRS), transverse (TS), and superior sagittal (SSS) sinuses in addition to the arterial segments of the circle of Willis were insonated through the temporal bone window on 2 consecutive days by 2 experienced examiners. The examiners were blinded to each other's results. The interobserver and intraobserver reliability was calculated using a method described by Bland and Altman, resulting in 2-SD confidence intervals., Results: Non-angle-corrected and angle-corrected systolic and end diastolic venous flow velocities (FV) were in good accordance with published normal values, ranging between 8.6 and 19.2 cm/s. The interobserver reliabilities for non-angle-corrected systolic FVs in the dMCV, BV, VG, SRS, and TS were +/- 1.8, 2.4, 2.6, 3.3, and 4.6 cm/s; for angle-corrected systolic FVs, the interobserver reliabilities were +/- 2.5, 3.1, 13.9, 11.6, and 7.7 cm/s. The intraobserver reliabilities for non-angle-corrected systolic FVs in the dMCV, BV, VG, SRS, and TS were +/- 2.9, 3.2, 2.6, 3.2, and 6.1 cm/s; for angle-corrected systolic FVs, the intraobserver reliabilities were 3.2, 3.7, 13.9, 11.6, and 7.5 cm/s. Angle correction was not attempted for the SSS. The interobserver and intraobserver reliabilities for systolic FVs in the SSS were +/- 3.3 and +/- 3.3 cm/s, respectively., Conclusions: Intracranial venous FVs can be measured with a high interobserver and intraobserver reliability in healthy human subjects. Intraobserver reliability was higher for cerebral veins than for dural sinuses, predisposing them for follow-up examinations; however, angle correction for venous FVs in the VG and the SRS is not advisable.

Ultrasound contrast agents (UCAs) have a distinct diagnostic impact on transcranial Doppler (TCD) and duplex sonography. In addition to the properties of the UCA and ultrasound imaging modes, the duration of contrast enhancement depends on the administration mode. Infusion of UCAs may be appropriate for prolonging the diagnostically useful time of elevated Doppler intensity. Five sedated dogs were investigated by TCD during infusion with SonoVue, a new UCA consisting of sulfur hexafluoride microbubbles. The infusion rate was varied, and the time-intensity curves were analyzed. Infusion rate of 70 ml/h provided a stable mean level of increased Doppler intensity up to 24 to 26 dB over baseline, whereas a rate of 35 ml/h did not result in a stable plateau (range 8-19 dB over baseline [5 minutes after starting time]). The maximum increases in Doppler mean intensity (18.2 dB [35 ml/h] and 25.6 dB [70 ml/h]) were significantly different (P = .025). Pharmacokinetic analysis of SonoVue during inflow (by exponential functional fitting of the time-mean intensity curves) and elimination (by linear regression analysis) revealed no dose-related differences. This study demonstrated a dose-dependent level of increased Doppler mean intensity within the brain circulation during infusion of SonoVue. Unlike the bell-shaped course of Doppler signal enhancement seen after bolus injection, infusion generates a stable plateau, which is an important prerequisite for more advanced contrast applications.

Background and Purpose: Transcranial color-coded duplex sonography (TCCS) allows bedside imaging of intracranial hemodynamics and parenchymal structures. It provides reliable information regarding midline shift (MLS) in space-occupying hemispheric stroke. We studied the value of MLS measurement to predict fatal outcome at different time points after stroke onset., Methods: Forty-two patients with acute, severe hemispheric stroke were enrolled. Cranial computed tomography (CCT) and extracranial duplex sonography were performed on admission. TCCS was carried out 8+/-3, 16+/-3, 24+/-3, 32+/-3, and 40+/-3 hours after stroke onset. Lesion size was determined from follow-up CCT., Results: Twelve patients died as the result of cerebral herniation (group 1); 28 survived (group 2). Two patients received decompressive hemicraniectomy and were therefore excluded from further evaluation. MLS was significantly higher in group 1 as early as 16 hours after onset of stroke. Specificity and positive predictive values for death caused by cerebral herniation of MLS >/=2.5, 3.5, 4.0, and 5.0 mm after 16, 24, 32, and 40 hours were 1.0., Conclusions: TCCS helps to estimate outcome as early as 16 hours after stroke onset and thus facilitates identification of patients who are unlikely to survive without decompressive craniectomy. Because of its noninvasive character and bedside suitability, sonographic monitoring of MLS might be a useful tool in management of critically ill patients who cannot undergo repeated CCT scans.

Neurologic injury subsequent to decompression from diving may be due to paradoxical arterialization of venous gas emboli. Of 40 divers who performed 53 open water dives after being tested for a patent foramen ovale (PFO), arterial gas emboli were detected in 7 of 13 dives, which resulted in venous bubbles. In five of these seven dives, there was evidence of a PFO by contrast transcranial Doppler sonography, indicating an increased risk of arterializing venous bubbles in divers with a PFO.

Background and Purpose: A number of controlled trials have evaluated the benefit of intravenous thrombolysis in acute stroke with inconsistent results. None of these studies assessed the initial vascular status or provided information regarding the recanalization rate after therapy. Further trials need to clarify whether certain subgroups might possibly benefit more than others from intravenous thrombolysis. Therefore, a fast and valid method for assessment of cerebrovascular status is needed. In this multicenter study, we evaluated the potentials and limitations of color-coded duplex sonography (TCCS) for cerebrovascular status assessment in acute stroke patients before and after therapy. Furthermore, we compared the recanalization rate for patients referred to thrombolytic and conservative medical therapy., Methods: Fifty-eight patients suffering from hemispheric stroke were enrolled consecutively in 8 centers. Duplex sonography was performed on admission, 2 hours after start of therapy, and 24 hours after onset of symptoms. Therapy was started within 6 hours., Results: Intravenous thrombolysis was performed in 18 patients, conservative medical therapy in 39 patients, and early thromboendarterectomy in 1 patient. The middle cerebral artery (MCA) mainstem was patent in 29 patients (53.7%), occluded in 25 (46.3%), and was not assessable in 4 patients. Recanalization of the occluded MCA after 2 and 24 hours was diagnosed in 50% and 78% of the patients treated with rtPA and in 0% and 8% in the conservatively treated patients., Conclusions: Intravenous thrombolysis is highly effective in restoring blood flow after MCA occlusion. TCCS is suitable for assessment of the cerebrovascular status in acute stroke and therefore might define therapeutically relevant subgroups of patients in future stroke trials on the basis of their vascular pathology.

This study was conducted to investigate the early pulmonary effects of acute decompression in an animal model for human decompression sickness by CT and light microscopy. Ten test pigs were exposed to severe decompression stress in a chamber dive. Three pigs were kept at ambient pressure to serve as controls. Decompression stress was monitored by measurement of pulmonary artery pressure and arterial and venous Doppler recording of bubbles of inert gas. Chest CT was performed pre- and postdive and in addition the inflated lungs were examined after resection. Each lung was investigated by light microscopy. Hemodynamic data and bubble recordings reflected severe decompression stress in the ten test pigs. Computed tomography revealed large quantities of ectopic gas, predominantly intravascular, in three of ten pigs. These findings corresponded to maximum bubble counts in the Doppler study. The remaining test pigs showed lower bubble grades and no ectopic gas by CT. Sporadic interstitial edema was demonstrated in all animals--both test and control pigs--by CT of resected lungs and on histologic examination. A severe compression-decompression schedule can liberate large volumes of inert gas which are detectable by CT. Despite this severe decompression stress, which led to venous microembolism, CT and light microscopy did not demonstrate changes in lung structure related to the experimental dive. Increased extravascular lung water found in all animals may be due to infusion therapy.

Background and Purpose: Transcranial color-coded duplex sonography (TCCS) allows the noninvasive, easily reproducible measurement of midline dislocation (MLD) of the third ventricle in space-occupying stroke, even in critically ill patients. However, the method has been validated only in a small number of subjects. The aim of this study was to test the method under clinical conditions., Methods: In 61 prospectively recruited patients (mean age, 62+/-15 years) with supratentorial ischemic infarction or intracranial hemorrhage, the sonographic measurement of MLD was compared with cranial CT data in a 12-hour time window. Subgroup analysis was also undertaken for comparing TCCS and cranial CT measurements within a 3-hour time window., Results: One hundred twenty-two data pairs of TCCS and cranial CT MLD measurements were correlated within the 12-hour time window. TCCS and cranial CT measurements of MLD correlated both in the total patient group and in the different subgroups with coefficients of over 0.9. The 2-SD confidence interval of the difference between the TCCS measurements and the respective means of both methods in the total patient collective was +/-1.78 mm., Conclusion: TCCS provides a noninvasive, easily reproducible and reliable method for monitoring MLD of the third ventricle in stroke patients. It is particularly suitable for critically ill patients who are not fit for transportation.

Objective: To evaluate the influence of different Doppler system settings on time-intensity curves after ultrasound contrast agent (UCA) bolus injection. This is important for the comparison of different UCAs., Methods: Six sedated dogs were investigated with a transcranial Doppler system and Doppler power, sample volume size and high pass filter settings were modified during the procedure. Mean time intensity curves were determined and peak values of mean intensity as well as the decrease in Doppler intensity were compared for the different system settings. Three different UCAs were used (SonoVue(TM), BY963 and Levovist(TM))., Results: The Doppler time intensity curves showed a typical two phase decrease with a distribution phase alpha and an elimination phase beta with all three UCAs. Altering the system settings had a significant effect on the mean peak Doppler intensity for SonoVue(TM) (P=0.02) but not for BY963 or Levovist(TM) (P=0.07 and P=0.39, respectively), due to high variation of the Levovist(TM) and BY963 intensity values. There were no significant differences between the alpha slopes of BY963 and Levovist(TM) (P=0.96), or the beta slope of Levovist(TM) and SonoVue(TM) (P=0.62), when the results of all system settings were combined., Conclusion: Different Doppler system settings show no significant influence on the decrease of mean Doppler intensity, but have a significant effect on peak intensity.

Objective: To evaluate the diagnostic efficiency and accuracy of contrast-enhanced transcranial color-coded sonography (CE-TCCS)., Background: TCCS is hampered by insufficient ultrasonic penetration in 20% of cerebrovascular patients., Methods: In 47 patients whose basal arteries could not be assessed adequately, 59 TCCS examinations were performed before and after administration of the ultrasonic contrast agent (CA) Levovist. The assessability of different basal cerebral arteries after CA administration was evaluated off-line. Angiographic records were available from 11 patients., Results: Satisfactory investigation of the middle cerebral artery, the anterior cerebral artery, the P1 and P2 segments of the posterior cerebral artery, and the supraclinoid portion of the internal carotid artery siphon was possible in 5.1%, 28.8%, 35.6%, 55.9%, and 47.5% of patients before, and in 84.7%, 91.5%, 93.2%, 94.5%, and 93.2% of patients after contrast enhancement. Stenoses or occlusions of basal cerebral arteries were registered in 28 patients (60%). CE-TCCS diagnosis was confirmed by digital subtraction angiography or magnetic resonance angiography in 10 of the 11 patients, leading to positive and negative predictive values of 0.86 and 1.00., Conclusion: Contrast enhancement improves the diagnostic potential of TCCS significantly in patients with temporal bone window failure, and proved to be a reliable method for detecting middle cerebral artery and siphon occlusion.

Background and Objective: Transcranial color-coded sonography (TS) allows a noninvasive, accurate evaluation of lateral displacement of the third ventricle. The authors studied the prognostic value of TS monitoring of the midline shift (MLS) in acute hemispheric stroke., Method: Sixteen patients with acute middle cerebral artery (MCA) occlusion were investigated. On admission, the median modified Scandinavian Stroke Scale (mSSS) score was 6.0 (range, 5 to 8). Five patients died from cerebral herniation (group 1), 10 survived (group 2), and 1 patient (Patient 16) survived after decompressive surgery. TS was performed on days 1 to 4 (10 +/- 3, 32 +/- 4, 57 +/- 5, and 82 +/- 5 hours after onset of symptoms). Distance from the TS probe to the center of the third ventricle was measured both from the symptomatic (A) and asymptomatic (B) sides. MLS was calculated using the formula MLS = (A - B)/2., Results: Ten hours after stroke onset, MLS and mSSS scores were not significantly different between the two groups. At 32, 57, and 82 hours, MLS was higher in group 1 (32 hours, p = 0.001; 57 hours, p = 0.003; 82 hours, p = 0.023) whereas there was no difference in mSSS score after 32 hours. All patients with an MLS < 4 mm at 32 hours survived, whereas patients with an MLS > 4 mm died as a result of cerebral herniation, with the exception of the one patient who underwent decompressive hemicraniectomy., Conclusions: The study of MLS at 32 hours after stroke onset in patients with severe MCA infarctions may identify patients who are unlikely to survive. The value of MLS in determining the indication of decompressive craniectomy merits further study.

Transcranial color-coded duplex sonography is a recently introduced method for visualizing (1) the blood flow velocity of the basal cerebral arteries and (2) the brain parenchyma as an acoustic impedance image. Dislocation of the third ventricle due to space-occupying stroke is an important clinical marker. This study evaluated the dislocation of the third ventricle from the brain midline by transcranial duplex sonography in 10 healthy volunteers. The mean dislocation was 0.2 +/- 0.3 mm. Eighteen stroke patients were investigated within 12 hours by both duplex sonography and computed tomography (CT) and the dislocation of the third ventricle was measured. Correlation between the two methods was high (r = 0.87, N = 27). Twelve stroke patients divided into three subgroups according to the extent of the space-occupying effects of the lesion were followed for 3 weeks. The increase and decrease of the dislocation of the third ventricle over the time were monitored. In conclusion, transcranial duplex sonography is a reliable tool to monitor dislocation of the third ventricle due to space-occupying stroke.

Background and Purpose: Transcranial color-coded duplex sonography (TCCS) enables visualization of the intracranial parenchymal structures and measurement of blood flow velocity in the basal cerebral arteries. The present study aims to evaluate prospectively the clinical usefulness of TCCS in patients with acute stroke., Methods: Eighty-four consecutive patients with central nervous symptoms suggesting acute stroke were investigated within the first 48 hours after clinical onset. TCCS was performed with a 2.5-MHz sector transducer through the temporal bone window. CT was available in all patients., Results: Forty-eight patients suffered from an infarction or a transient ischemic attack (TIA) in the territory of the middle cerebral artery (MCA). Fifteen of them showed an MCA occlusion, and 12 of the 15 developed recanalization during follow-up. Twelve revealed an increased, decreased, or oscillating flow pattern in the MCA main stem, and 21 patients had no ultrasonic abnormalities. The positive and negative predictive values of a pathological flow pattern in patients with MCA infarctions or TIA were .92 and .48, respectively. Fifteen patients suffered from an intracerebral hematoma, which could be diagnosed by TCCS in 14 cases. The positive and negative predictive values of a pathological parenchymal echo pattern were .88 and .96, respectively. Three patients suffered from an infarction and one from a TIA in the posterior cerebral artery territory. One female patient with an acute deterioration of a hemiparesis showed a glioma. The dropout rate due to an insufficient acoustic temporal bone window was 20% (17/84)., Conclusions: TCCS is a noninvasive bedside method that provides rapid and reliable data regarding stroke subtype and mechanism immediately after onset. Window failure is a serious limitation of this method.

Transcranial duplex color-flow sonography provides visualization of intracranial structures, and measures angle-corrected blood flow velocity in the basal cerebral arteries of adults. In 44 patients with central nervous system disease, the oblique diameters of the third and the middle part of the lateral ventricle were measured by transcranial duplex color-flow sonography using a system with a 2.5-MHz transducer, and compared to computed tomography measurements. The correlation coefficients for the third and lateral ventricle measurements were r = 0.83 (p < 0.0001, N = 38) and 0.73 (p < 0.0001, N = 78), respectively. A second investigation was performed by transcranial duplex to evaluate intraobserver and interobserver reproducibility. The correlation coefficient representing interobserver reproducibility in 27 patients was r = 0.87 (p < 0.0001, N = 47) for the lateral ventricle and r = 0.9 (p < 0.0001, N = 49) for the third ventricle. The intraobserver reproducibility correlation coefficient was r = 0.93 (p < 0.0001, N = 22) for the lateral ventricle in 12 patients. In 49 healthy volunteers the oblique diameters of the lateral and third ventricles were age dependent, measuring 16.7 +/- 2.3 mm and 4.8 +/- 1.9 mm, respectively, in those younger than 59 years, compared to 19.0 +/- 2.9 mm and 7.6 +/- 2.1 mm in those 60 years or older. Therefore, transcranial duplex color-flow sonography measures noninvasively the third and the lateral ventricle in adults.