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W Steinke

Publications and source records attributed to W Steinke.

At least 37 records · Page 2Linked to original sources
PubMed1998

Biotransformation of cerivastatin in mice, rats, and dogs in vivo.

Biotransformation of cerivastatin was investigated in mice, rats, and dogs in vivo using the 14C-labeled drug. Marked species differences exist, both in pathways and extent of cerivastatin metabolism. Unchanged drug, together with its lactone, predominates in dog plasma and represents 40% of the dose in the excreta, whereas in rat bile they account for approximately 10% of the dose. In mice, the drug is metabolized rapidly and almost completely. Biotransformation of cerivastatin occurs by three distinct phase I routes and by phase II conjugation with sugar-type moieties and taurine. Phase I routes are demethylation of the pyridinyl methyl ether, beta-oxidation of the 3,5-dihydroxy acid side chain, and reductive removal of the side chain 3-hydroxy group. In dogs, demethylation is the dominating phase I biotransformation. Phase II conjugation is equally important. In dog bile, different regioisomeric drug glucuronides and the benzylic glucuronide and glucoside conjugate of the demethylated drug were found. In rats, besides demethylation, beta-oxidation of the dihydroxy acid side chain-followed by reductive removal of the 5-hydroxy group-is the major reaction. The resulting pentenoic acid derivatives are observed in plasma and liver homogenate. These metabolites are subsequently conjugated with taurine and excreted in the bile. This metabolic sequence is also important in mice. Furthermore, only in mice, cerivastatin is subject to reductive removal of the 3-hydroxy group, together with demethylation. The 5-hydroxyheptenoic acids formed predominate in plasma and liver homogenate, whereas the corresponding taurine conjugates are excreted in the bile.

Animals↗
PubMed1997

Cerebrovascular involvement in the acute phase of bacterial meningitis.

Cerebral ischaemia is a common complication of bacterial meningitis. Although cerebrovascular involvement in the acute phase of inflammation may be particularly important for the still unacceptably high morbidity and mortality, only, a few studies have investigated cerebrovascular changes in bacterial meningitis. We prospectively investigated changes of intracranial cerebral blood flow velocities (CBFV) in 22 patients (12 men, 10 women, mean age 48 years, 19 years, SD) with bacterial meningitis, by means of transcranial Doppler sonography (TCD). According to previously published criteria the degree of arterial narrowing was assessed and related to the patients' outcome. Elevated CBFVs in the middle cerebral artery were documented in 18/22 patients with markedly increased systolic peak velocities (CBFV of > 210 cm/s) in 7 patients. Serial examinations performed in 11 patients showed elevated CBFV as early as day 1, reaching peak CBFV between day 3 and day 6 after onset of symptoms in most cases. Furthermore, cerebrovascular involvement was also documented by disturbances of physiological slow spontaneous oscillations of blood flow velocities in 5/10 patients examined with TCD. Low Glasgow Coma Scales (< 7) on admission (29% vs 0%), focal cerebral ischaemic deficits (29% vs 7%) and, seizures (43% vs 7%) were more frequent in patients with CBFV of > 210 cm/s. Finally, a poor clinical outcome was significantly related to severe vascular involvement (P < 0.05). In conclusion, cerebrovascular complications are frequently found in patients with bacterial meningitis. TCD is an easily applicable technique for revealing vascular changes non-invasively, even in severely ill patients. Since our data suggest an unfavourable course of the disease in association with increased CBFV in intracranial arteries, probably indicating vasospasm, TCD could potentially be used to identify high-risk patients who could benefit from adjuvant therapeutic interventions.

Adult↗
PubMed1997

Mechanisms of infarction in the superficial posterior cerebral artery territory.

Numerous reports have described a variety of clinical syndromes resulting from posterior cerebral artery (PCA) infarction, whereas only a few pathoanatomical and retrospective clinical studies have investigated the underlying mechanisms. Therefore we attempted to determine the causes of infarction in the superficial posterior cerebral artery (PCA) territory by means of a more comprehensive, modern vascular and cardiac study. During a 4-year period 74 consecutive patients (49 men, 25 women) with acute PCA infarction documented on CT (n = 74) and MRI (n = 41) were included in the study. Patients had a neurological examination, vascular studies [extra- and transcranial Doppler (n = 74), magnetic resonance (n = 31) or intra-arterial (n = 22) angiography], cardiac evaluation [ECG (n = 74), transthoracic (n = 74) and transoesophageal echocardiography (n = 30)], and coagulation tests. A cardiac source of embolism was established in 31%, significant vertebrobasilar artery disease in 22%, and PCA stenosis or occlusion in 8% of the patients. Rare causes, such as hypercoagulopathy or paradoxical embolism via a patent foramen ovale, were present in 15%. However, in spite of the comprehensive diagnostic evaluation, the cause of the stroke remained undetermined in 24% of the cases. Apart from complete infarcts of the posterior branches of the PCA, which occurred more frequently in cardioembolic strokes (18%, P < 0.05), the topographical patterns of infarct extension and the coincidence of infarction in the deep territories of the PCA, the cerebellum and brainstem were not significantly different among the causal subgroups. The frequency of haemorrhagic transformation (18%) was highest among cardioembolic strokes (44%, P < 0.001). This prospective study of PCA infarction demonstrated embolism from cardiac and vascular sources as the predominant cause. In contrast to previous studies, we found no evidence of migraine as a cause of PCA infarction, whereas paradoxical embolism was the presumed cause in a considerable number of cases. Whereas the cause of stroke could not reliably be derived from infarct topography, haemorrhagic transformation indicated there had been cardioembolism in most cases.

Adolescent↗
PubMed1997

Power Doppler imaging of carotid artery stenosis. Comparison with color Doppler flow imaging and angiography.

BACKGROUND AND PURPOSE: Power Doppler imaging (PDI) is a new sonographic technique that has recently been introduced for vascular application. Since the technical principles of PDI may provide increased sensitivity to visualize the continuity of blood flow in arterial stenoses, we investigated the diagnostic significance of PDI and the intermethod relationship for the measurement and classification of internal carotid artery (ICA) stenosis in comparison with both color Doppler flow imaging (CDFI) and angiography. METHODS: One hundred patients with a total of 128 ICA stenoses (50% to 69%, n = 37; 70% to 79%, n = 27; 80% to 99%, n = 64) and 12 ICA occlusions were consecutively investigated by means of PDI, CDFI, and intra-arterial angiography (n = 48). Reduction of the intrastenotic lumen was measured on longitudinal and transverse views of PDI and CDFI for the calculation of the degree of diameter and area stenosis, respectively. Angiographic stenosis was determined with the use of the North American Symptomatic Carotid Endarterectomy Trial (NASCET), European Carotid Surgery Trial (ECST), and common carotid (CC) methods. RESULTS: PDI provided significantly more excellent or good (92% versus 79%; P < .01) displays of the intrastenotic lumen than CDFI, particularly in complicated high-grade stenosis. While linear regression analysis demonstrated a high overall correlation between PDI and CDFI for diameter (r = .88; P < .001) and area stenosis (r = .79; P < .001), categorization of ICA stenosis revealed best agreement for 80% to 99% area stenoses. Since angiography frequently either underclassified (NASCET method) or overclassified (ECST, CC methods) the degree of ICA stenosis in comparison to both PDI and CDFI, the sonographic-angiographic correlation was only moderate (regression coefficients ranged from .62 to .70; P < .001). CONCLUSIONS: PDI further improves the assessment of ICA stenosis by providing better visualization of the stenotic vascular lumen than CDFI. Sonographic imaging of the stenotic plaque on both PDI and CDFI provided a direct measurement of the local degree of stenosis, while the angiographic grade of stenosis essentially depended on the method used for evaluation.

Adult↗
PubMed1997

Echocontrast-enhanced transcranial color-coded sonography for the diagnosis of transverse sinus venous thrombosis.

BACKGROUND AND PURPOSE: Early diagnosis of cerebral transverse sinus venous thrombosis (TSVT) is difficult because of nonspecific and variable clinical presentations. Therefore, we evaluated the diagnostic value of transcranial color-coded duplex sonography (TCCS) after administration of an echocontrast-enhancing agent (cTCCS) in clinically suspected TSVT. METHODS: We examined 14 patients (6 men, 8 women; mean age, 48 years; range, 18 to 70 years) with signs and symptoms suggestive of cerebral TSVT. Color-coded signals from the contralateral transverse sinus were displayed transtemporally before and after injections of an echocontrast agent by TCCS. Sonographic findings were correlated with MRI and MR venography (MRV). RESULTS: Before echocontrast enhancement, TCCS displayed color Doppler signals in 7 of 28 transverse sinus. Echocontrast TCCS obtained sufficient color signals in 27 of 28 transverse sinus. Thus, diagnostic confidence was achieved in all but 1 patient. In 13 patients, cTCCS identified 3 cases with symmetrical blood flow in the transverse sinus, which was confirmed by MRV. Accordingly, asymmetry of venous blood flow was correctly assessed by cTCCS in the other 10 patients. In 6 of these 10 patients, cTCCS demonstrated residual color flow signals, which on MRI/MRV corresponded to partial TSVT (4 cases) and to hypoplasia (1 case) of the transverse sinus. One case of complete thrombotic occlusion of the transverse sinus was missed by cTCCS because of color Doppler signals originating from an adjacent dural fistula. Echocontrast TCCS diagnosis of occlusion of a transverse sinus was confirmed by MRI/MRV in all cases (aplasia of transverse sinus, n = 1; complete TSVT, n = 3). Systolic peak flow velocities were significantly decreased in hypoplastic or partially occluded transverse sinus (9.4 +/- 4.0 cm/s) and significantly increased contralaterally (28.4 +/- 6.5 cm/s) with respect to patients with symmetrical appearance of the transverse sinus (17.5 +/- 1.9 cm/s) (P < .05). CONCLUSIONS: TCCS examination of the cerebral venous system is difficult without contrast media application and almost useless for the study of TSVT. However, cTCCS is of practical value in the initial workup of patients with clinically suspected TSVT and may provide further insight for follow-up studies in view of monitoring the recanalization.

Adolescent↗
PubMed1997

Pharmacokinetics of miglitol. Absorption, distribution, metabolism, and excretion following administration to rats, dogs, and man.

The absorption, distribution, metabolism, and excretion of miglitol ((2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl)-3,4,5-piperidinet riol, CAS 72432-03-2, BAY m 1099) have been studied following single and repeated administration of non-labelled and radiolabelled (3H, 14C) drug to rats, dogs, and human volunteers via different routes of administration (intravenous, oral, intraduodenal) and at various doses (0.3-450 mg/kg). After intravenous administration, miglitol is excreted rapidly and completely via the renal route. No indication was found for a metabolization of radiolabelled miglitol. The (renal) clearance of miglitol is in the range of the glomerular filtration rate. Miglitol is rapidly eliminated from plasma with apparent elimination half-lives of 0.4-1.8 h. Miglitol is virtually not bound to plasma proteins. After oral administration miglitol is rapidly and at low doses also completely absorbed. At higher doses (> or = 5 mg/kg in rats and dogs, > 50 mg in humans) a saturation of absorption becomes evident. Miglitol is distributed predominantly in the extracellular space. The volumes of distribution are low (0.3-0.8 l/ kg). In rats high concentrations were initially found in the kidneys, the blood and some well-perfused tissues. The permeation across the blood/brain barrier is very low. Elimination from organs and tissues occurs rapidly resulting in very low residual radioactivity in the body 2 days after dosing (< 0.9% of the dose). At this very low concentration level a terminal elimination phase of radioactivity characterized by half-lives of 50-110 h was observed giving rise to a slight tendency for accumulation (accumulation factors < 6) following repeated administration to rats. In pregnant rats [14C]miglitol crossed the placental barrier slowly and to a limited extent. In lactating rats miglitol was found in milk in concentrations similar to those in the maternal plasma.

1-Deoxynojirimycin↗
PubMed1997

Pharmacokinetics and metabolism of the new thromboxane A2 receptor antagonist ramatroban in animals. 1st communication: absorption, concentrations in plasma, metabolism, and excretion after single administration to rats and dogs.

The absorption, concentrations in plasma, metabolism and excretion of ramatroban ((+)-(3R)-3-(4-fluorophenylsulfonamido)-1,2,3,4-tetrahydro-9- carbazolepropanoic acid, CAS 116649-85-5, BAY u 3405) have been studied following a single intravenous, oral, or intraduodenal administration of 14C-labeled or nonlabeled compound to rats and dogs (dose range: 1-10 mg.kg-1). After intraduodenal administration of [14C]ramatroban, enteral absorption of radioactivity was rapid and almost complete both in bile duct-cannulated male rats (83%) and female dogs (95%). The oral bioavailability of ramatroban was complete in the dog but amounted to about 50% in the rat due to presystemic elimination. A marked food effect on the rate but not on the extent of absorption was observed in rats. The elimination of the parent compound from plasma occurred rapidly with total clearance of 1.2 l.h-1.kg-1 in male rats and 0.7 l.h-1.kg-1 in dogs. After oral administration to male rats AUC increased dose-proportionally between 1 and 10 mg.kg-1, whereas in Cmax an over-proportional increase was observed. Excretion of total radioactivity was fast and occurred predominantly via the biliary/fecal route in both species. The residues were low, 144 h after dosing less than 0.2% of the radioactivity remained in the body of rats. A considerable sex difference was found in rats following oral administration of ramatroban. In females a 3-fold higher AUC and a 1.7-fold longer half-life of unchanged compound, as well as 3-fold higher renal excretion of total radioactivity was observed. A marked species difference exists in the metabolism of ramatroban. In dogs the drug was almost exclusively metabolized via conjugation with glucuronic acid, whereas in rats oxidative phase I metabolism and glucuronidation were equally important. As a consequence enterohepatic circulation was much more pronounced in dogs (77%) than in rats (17% of the initial dose).

Administration, Oral↗
PubMed1997

Pharmacokinetics and metabolism of the new thromboxane A2 receptor antagonist ramatroban in animals. 2nd communication: distribution to organs and tissues in male, female and pregnant rats, and characteristics of protein binding in plasma.

The distribution to organs and tissues, placental transfer and mammary excretion of ramatroban ((+)- (3R)-3-(4-fluorophenylsulfonamido)-1,2,3,4-tetrahydro-9- carbazolepropanoic acid, CAS 116649-85-5, BAY u 3405) have been investigated in rats. Furthermore, the characteristics of protein binding in plasma of various species including man are described. After single oral administration of [14C]ramatroban to male rats, the radioactivity was preferentially localized in liver and kidneys, the tissue-to-plasma concentration ratios at tmax were 20 for liver and 6.3 for kidneys, respectively. For all other organs/tissues, a low to moderate affinity was detected. [14C]Ramatroban and its labeled metabolites did hardly penetrate the blood-brain barrier, and the brain-to-plasma concentration ratio was 0.03 at tmax. After repeated oral administration to male rats for 21 days, once daily, the radioactivity concentrations in organs and tissues showed only a slight tendency to accumulate. The AUC ratios in the dosing interval exhibited little or no increase, the highest accumulation factor was approximately 2. The steady-state of the trough levels in plasma was reached rapidly, with the third administration. The autoradiographic distribution pattern was not changed due to repeated administration. After receiving single oral doses of [14C]ramatroban, female rats showed almost identical autoradiographic distribution patterns of radioactivity compared with males. Although being similarly distributed, in most organs and tissues of pregnant rats (19th day of gestation) distinctly higher radioactivity concentrations were observed than in males. Maximal fetal concentrations occurred at 7 h after dosing. The distribution in fetuses was similar to that in maternal body, revealing relatively high concentrations in liver, kidneys, and gastrointestinal contents. The fetal AUC reached 68% of the AUC in maternal plasma. [14C]Ramatroban was excreted with the milk of lactating rats. The total amount within 24 h was estimated to be 1.7% of the maternal dose. [14C]Ramatroban is highly bound to plasma proteins in all species tested: rabbit (unbound fraction: 1.7-1.9%), rat (2.1-2.4%), man (2.0-2.7%), dog (2.4-2.8%), mouse (3.7-4.1%), guinea-pig (4.3-4.7%).

Administration, Oral↗
PubMed1996

Topography of cerebral infarction associated with carotid artery dissection.

Because the pathogenesis of cerebral ischaemia in internal carotid artery dissection (ICAD) is controversial we studied the topography of cerebral infarction that results from ICAD according to pathophysiology of embolic and haemodynamic stroke. Sixty-four patients with 67 ICADs diagnosed by angiography, Doppler duplex sonography and magnetic resonance imaging (MRI) were studied prospectively during the past decade. According to current pathophysiological concepts, cortical territorial infarcts and large subcortical lenticulostriate infarcts revealed by CT or MRI were classified as embolic, while smaller infarcts in the subcortical junctional zone and infarcts in the cortical borderzone between the middle (MCA) and anterior cerebral artery were interpreted as haemodynamic infarcts. Of the 67 dissections 37 (55%) were associated with brain infarcts, of which territorial MCA infarcts of variable size accounted for 60%. These were combined with infarcts of the anterior and posterior cerebral artery in 5%; 8% of the patients had complete MCA infarction. Large lenticulostriate infarcts were present in 11%. Haemodynamic infarcts involved the subcortical junctional zone in 16% but never the anterior cortical borderzone. Although different abnormal Doppler findings indicated haemodynamically significant carotid obstruction in all symptomatic ICADs, only the characteristic high-resistance Doppler signal was significantly associated with the occurrence of brain infarction (in 66%, P < 0.01). The angiographic features of ICAD did not correlate with the incidence or with the topography of cerebral infarction. Patterns of infarction in ICAD indicate a predominantly embolic causation probably due to thrombus formation in the dissected carotid artery in the presence of severe haemodynamic obstruction, as demonstrated by Doppler sonography.

Adolescent↗
PubMed1996

[Spiral CT angiography in stenoses of the middle cerebral artery].

INTRODUCTION: Transcranial Doppler ultrasonography (TCD) and magnetic resonance angiography (MRA) are well-established techniques for ascertaining intracranial obstructive artery disease. The short examination time required for additional helical CT angiography (CTA) allows quick management of emergency patients already undergoing native CT. However, today the ability of CTA to detect stenoses of the middle cerebral artery (MCA) has not been proven. To analyse the value of CTA in the classification of atherosclerotic disease 23 MCA stenoses confirmed by TCD and MRA were investigated. METHODS: CTA was performed on a Hispeed advantage scanner (GE) using a bolus injection of 70 ml KM and 40 ml NaCl with a flow rate of 2.5 ml/s, a thickness of 1 mm, a pitch of 1.5 and a 1 mm increment. CTA was presented as maximum intensity projection (MIP) and as multi-projection volume reconstruction (MPVR). A three-step classification of stenosis was compared with the results of TCD and MRA. RESULTS: Good opacification of the MCA was achieved in M1 and M2 segments in all patients. Classification of stenosis by CTA agreed with MRA and TCD in 14 cases; 7 stenoses were assigned to a lower classification by CTA. Two low-grade stenoses could not be proven by CTA. Although MIP and MPVR yield the same result in stenosis classification MPVR showed a sharper image quality. In contrast to MRA, veins were highly opacified in CTA. Artery and vein were sometimes superimposed, which had to be avoided by changing the projection angle. CONCLUSION: Medium- and high-grade MCA stenoses can be demonstrated by CTA quickly and reliably. Compared to MRA and TCD, CTA provides lower grading of stenosis.

Blood Flow Velocity↗
PubMed1996

Ischemia-induced migraine from paradoxical cardioembolic stroke.

Although little is known on the pathophysiologic mechanism of migraine-related stroke, the prevailing attitude is that vasoconstriction and activation of clotting factors play a primary role. In 2 female patients presenting with migraine and stroke, risk profiles and history were consistent with this pathophysiologic mechanism. Cerebro- and cardiovascular workup, however, led to a diagnosis of paradoxical cardioembolic stroke through a patent foramen ovale. Since there is hardly any evidence in the literature that migraine acts as a risk factor for stroke on its own, these case reports emphasize the importance of complete cardiovascular evaluation in patients with suspected migrainous stroke.

Adolescent↗
PubMed1996

Sonographic assessment of carotid artery stenosis. Comparison of power Doppler imaging and color Doppler flow imaging.

BACKGROUND AND PURPOSE: Power Doppler imaging (PDI) is a new ultrasound technique that, in contrast to color Doppler flow imaging (CDFI), generates intravascular color signals from the reflected echo amplitude depending mainly on the density of red blood cells. We evaluated the diagnostic significance of PDI compared with CDFI for the measurement of carotid stenosis and characterization of plaque surface. METHODS: In 25 internal carotid artery stenoses, reduction of the intrastenotic lumen contrasted by blood density signals and color Doppler signals on longitudinal and transverse views was assessed for correlative evaluation. In addition, the peak systolic flow velocity of the Doppler spectrum was correlated with PDI and CDFI measurements. RESULTS: PDI provided good visualization of the residual lumen in all stenoses, whereas displays on CDFI were inadequate in two calcified plaques. PDI revealed two ulcerative stenoses classified as smooth on CDFI. The correlation between PDI and CDFI was high for measurement of area stenosis (r = .93) and moderate for diameter stenosis (r = .73). Similarly, cross-sectional reduction on both imaging methods correlated more significantly with peak systolic flow velocity than diameter reduction. CONCLUSIONS: This pilot study suggests that PDI provides additional information for luminal measurement and characterization of plaque surface in complicated high-grade carotid stenosis. Because of the absent visualization of hemodynamics, PDI should be used in combination with CDFI.

Aged↗
PubMed1996

[Cerebral artery dissection].

The main symptom of arterial dissection is intense acute unilateral headache. The pain is commonly located around the eye, in the temple or the front with a carotid artery dissection [CAD] and in the posterior neck and occiput with a vertebral artery dissection [VAD]. Transient or persistent cerebral ischemic symptoms are similarly frequent but usually occur later in the time course. Horner's syndrome indicating a lesion of perivascular sympathetic fibres represents the third leading symptom and occurs in more than one third of the patients. Compression of local structures such as lower nerve or radicular palsies is rare. This constellation of symptoms in a young patient without vascular risk factors should rise suspicion of a dissection, in particular, if there is a preceding 'trivial' trauma. Characteristic features on Doppler/duplex sonography provide the diagnosis of dissection in almost all CAD and the majority of VAD. MRI demonstrating the mural hematoma allows reliable confirmation of the suspected diagnosis. Angiography is necessary only in selected cases, more often in VAD than in CAD. Brain infarction may be prevented, if premonitory symptoms, which occur in 60 to 80% of the patients, are recognized as such. Therefore, if there is clinical and sonographic suspicion of CAD or VAD, anticoagulation therapy with heparin should should be started before other imaging procedures finally prove the diagnosis. Because immediate anticoagulation may prevent cerebral embolism, this treatment strategy seems appropriate, although its efficacy has not been established by a controlled study. Anticoagulation should be continued until resolution of the dissection.

Adult↗
PubMed1994

Pathophysiologic assessment of data from a stroke data bank.

Stroke data banks have been instrumental in helping us to clarify stroke etiology and in the investigation of clinical-topographic correlations. For these purposes they have relied upon results from noninvasive vascular and cardiac methods, including extra- and transcranial Doppler sonography and echocardiography, as well as from procedures such as cranial computed tomography and magnetic resonance imaging. Conventional database concepts have also been used to assess pathophysiologic aspects of stroke. Although such applications have made important contributions in this multidiscipline area of investigation, they are limited by a lack of explicit representation of pathophysiologic knowledge for data interpretation. Recent results from artificial intelligence research suggest exciting new frontiers for medical database design with concepts stemming from second generation expert systems. We propose an extended concept for stroke data banks to include a knowledge-based system which incorporates current patient data, heuristic knowledge relating clinical features to functional impairment, and pathophysiologic models of neurological disease.

Cerebrovascular Disorders↗
PubMed1994

Compensatory carotid artery dilatation in early atherosclerosis.

BACKGROUND: From pathological studies of coronary arteries, it has been recognized that progressive plaque development may be compensated for by an increase of the arterial diameter. However, the dynamics of this process have not been investigated, and it is not known whether compensatory dilatation is a general pathomechanism in human arteries. METHODS AND RESULTS: Using a high-resolution duplex scanner and subsequent three-dimensional plaque reconstruction, we prospectively studied the effect of carotid plaque development on the vascular geometry in 32 patients at 6- to 12-month intervals. Plaque progression in 41% (n = 26) of studies was associated with an increase of the vessel diameter between 0.4 and 1.2 mm in 76% (n = 20). Among 36 unchanged plaque developments, enlargement of the arterial diameter was assessed in only 28% (n = 10) (P < .001). CONCLUSIONS: Our data suggest that increasing plaque volume is significantly associated with enlargement of carotid artery segments, which compensates for arterial narrowing in early stages of the disease.

Aged↗
PubMed1994

Noninvasive monitoring of internal carotid artery dissection.

BACKGROUND AND PURPOSE: Internal carotid artery dissection has increasingly been reported as a cause of transient ischemic attack or stroke. However, scarce data exist on the natural history of the arterial lesions and the temporal profile of recanalization. METHODS: We followed 48 patients with 50 angiographically confirmed internal carotid artery dissections by sequential duplex Doppler studies in 2- to 4-day intervals during the first weeks after the onset of symptoms and after 4 weeks in 1- to 2-month intervals for up to 2 years. We assessed sonographic features as well as the frequency and time course of resolution. RESULTS: Initial Doppler findings were abnormal in all patients, most of whom (68%) presented with a characteristic bidirectional high-resistance Doppler signal in the internal carotid artery. Gradual recanalization was found in 68% of the dissections after an average interval of 51 days. Changes of Doppler flow patterns in follow-up studies and features of intra-arterial angiography correlated with the development of internal carotid artery dissection and mirrored the recanalization process. CONCLUSIONS: Our findings suggest that Doppler sonography provides early recognition of internal carotid artery dissection and monitoring of its resolution. Thus, ultrasound studies may guide clinical decisions according to the development of the dissection.

Adolescent↗