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  • 1
    ISSN: 1433-8491
    Keywords: Doppler sonography ; Basilar artery thrombosis ; Doppler-Sonographie ; Basilaristhrombose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei 6380 Doppler-Untersuchungen in den letzten $$3{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}$$ Jahren wurde in sieben Fällen eine hochgradige Zirkulationsstörung der A. basilaris bzw. beider distaler Vertebralarterien angenommen. Kriterium dafür war, daß die Vertebralarterien entweder beidseits nicht darstellbar waren oder keine diastolische Flußkomponente aufwiesen („externa-a-typische” Pulskurven). Die in sechs Fällen anschließend erfolgte Angiographie bestätigte die Diagnose: Viermal fand sich ein Basilarisverschluß, einmal eine langstreckige Basilarisstenose und einmal ein beidseitiger distaler Vertebralisverschluß. Drei weitere im gleichen Zeitraum angiographisch diagnostizierte Basilarisverschlüsse erfüllten bei der Doppler-sonographischen Erstuntersuchung nicht die oben genannten Kriterien, zwei davon auch nicht bei wiederholter Untersuchung. Die Doppler-Sonographie der Vertebralarterien kann somit als ein wesentliches diagnostisches Hilfsmittel beim Nachweis signifikanter Läsionen auch der distalen A. vertebralis und der A. basilaris gelten.
    Notes: Summary We have investigated 6,380 patients with directional c-w Doppler sonography within the last $$3{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}$$ years, and have suspected obstruction of the basilar artery or of both distal vertebral arteries in 7 cases. Either bilateral sonographic silence or an absent diastolic flow component of the vertebral arteries were employed as criteria in the sonographic evaluation. Angiography of the vertebro-basilar system, performed in 6 cases, confirmed the diagnoses: basilar artery occlusion was found in 4 patients, 1 patient revealed tight stenosis of the basilar artery in its entire length, and 1 patient exhibited occlusion of both distal vertebral arteries. Three further basilar artery occlusions were detected by means of angiography despite initially negative Doppler sonography within the same period of time; l of those patients, however, met the above criteria for basilar artery occlusion upon sonographic reevaluation on the following day. Thus, we believe that directional c-w Doppler sonography is very useful in the diagnosis of basilar artery obstruction.
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  • 2
    ISSN: 1433-8491
    Keywords: Ultrasonic Doppler ; Vertebral artery ; Basilar artery ; Vertebro-basilar insufficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have examined the vertebral and subclavian arteries in 1,205 patients using directional continuous-wave (c-w) Doppler sonography, and compared the sonographic findings with the results of unilateral or bilateral retrograde brachial arteriographies in the same patients. Doppler sonography revealed 33 false positives among 909 cases with normal angiographic findings. Some types of vertebral artery (VA) lesions allowed an excellent, others a fairly good differentiation by Doppler sonography: the complete subclavian steal syndrome with constant reversal of VA flow was reliably detected (16 cases). In the incomplete steal syndrome (5 cases) sonography was superior to angiography. Two bilateral distal VA occlusions and seven basilar artery occlusions — six in the proximal third and one in the rostral third — were detected sonographically; four basilar occlusions sparing the caudal third and one case exhibiting rete mirabile anastomoses were not identified by Doppler sonography. Our acoustically defined sonographic criteria did not permit an unequivocal assignment to an anatomical variant or a vascular lesion. The sensitivity in the detection of a severe stenosis at the VA origin amounted to 16 out of 31, and to 12 of 25 in cases with a proximal VA occlusion and reconstitution of the distal VA through cervical collaterals. Our results confirm that the conventional hand-held c-w Doppler sonography cannot replace angiography in the evaluation of vertebro-basilar insufficiency. It rather serves as an aid to the decision for or against angiography, and in the follow-up of angiographically proven lesions. However, several therapeutically important lesions are readily diagnosed by sonography.
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  • 3
    ISSN: 1433-8491
    Keywords: Basilar artery stenosis ; Basilar artery occlusion ; Continuous-wave Doppler sonography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the past 5 years we have investigated 29 patients with symptomatic basilar artery stenoses (14 cases) and occlusions (14) and a patent primitive trigeminal artery with thin-calibered basilar and vertebral arteries (1) using directional continuous-wave Doppler sonography of the vertebral arteries. A total of 19 patients survived, and 17 of them were clinically and sonographically reexamined after 40.4 ± 15.8 months (mean ± SD). Among the 8 patients with basilar stenoses, 6 — with no further transient ischemic attacks (TIAs) in the interval — exhibited an increase in the summed modified Pourcelot indices (relative end-diastolic flow velocities) of the vertebrals by 0.18 ± 0.16; the other 2 showed a decrease by 0.26 each, in 1 case temporally related to a TIA, in the 2nd case without further clinical deterioration. In the 8 survivors with basilar occlusions, 5 remained — by sonographic criteria — unchanged with summed modified Pourcelot indices of the vertebrals of 0.00, while 3 patients exhibited a slight increase in the summed modified Pourcelot indices of 0.13 ± 0.03. While the difference between the outcome of subsets of patients treated with regimens of 30,000–40,000 units heparin/day or phenprocoumon and less radical drugs were statistically not significant, the former regimen appeared clinically more efficacious in preventing further deterioration in approximately two-thirds of the patients affected. Due to the potential recurrence of neurological symptoms, a treatment period with phenprocoumon of 6 months after discharge from hospital appears justified. Due to these therapeutic efforts, approximately half of the patients initially affected survived with no or only a mild neurological deficit. Directional continuous-wave Doppler sonography is, in our opinion, a reliable technique for examining the short- and long-term changes in peripheral vascular resistance.
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  • 4
    ISSN: 1433-8491
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 5
    ISSN: 1432-1440
    Keywords: Adriamycin cardiomyopathy ; Isolated embryo ventricular cells ; Increment of Ca i 2+ ; Ionic flux measurements ; Adriamycin-Cardiomyopathie ; Isolierte Herzmuskelzellen ; Intracelluläre Calciumerhöhung ; Ionenflußmessungen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Cytostatikum Adriamycin verursacht bei Einwirkung auf isolierte Herzmuskelzellen von Hühnerembryonen im Vergleich zu dem metabolischen Inhibitor 2,4-Dinitrophenol einen Abfall der Kontraktionsamplitude, einen Anstieg der Schlagfrequenz und eine „Nach-Kontraktion“. Durch radioaktive Messungen konnte als Ursache hierfür eine Erhöhung des frei-ionisierten cytoplasmatischen Calciums gefunden werden. Zu dieser Erhöhung war es durch eine Verminderung der Rückresorption des Calciums in das sarkoplasmatische Retikulum und die Mitochondrien gekommen. Folge dieser Ca-Erhöhung sind eine Veränderung des Aktionspotentials, der Refraktärperiode sowie, über eine Kontrolle des Kaliumflusses, das Auftreten der „Nach-Kontraktionen“.
    Notes: Summary As compared to the metabolic inhibitor 2,4-Dinitrophenol, the cytostatic drug Adriamycin influences the isolated embryo ventricular cells of the chicken, thus causing a decrease in the contraction amplitude, an increase in the heart-rate, and the occurrence of “after-contractions”. With radioactive measurements it could be demonstrated, that the reason therefore is an increment of Ca i 2+ . This may be explained by a decreased Ca-uptake by the sarcoplasmic reticulum and the mitochondria. This increment of Ca i 2+ brought about a change in the action potential and the refractory-period, as well as the occurrence of “after-contractions” by control of the potassium flux.
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  • 6
    ISSN: 1432-1920
    Keywords: Doppler sonography ; Intracranial carotid artery disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have investigated 6,587 patients with directional continuous-wave (c-w) Doppler sonography of the carotid arteries during the last 33 months, and have developed criteria for the diagnosis of a significant increase in peripheral resistance of the internal carotid artery in conjunction with 1,671 retrograde brachial and direct carotid angiograms. We distinguished stenoses proximal (15 cases) and distal (4) to the origin of the ophthalmic artery, supraclinoid internal carotid artery occlusions (8), stenoses (2) and acute occlusions (10) of the middle cerebral artery. Stenoses in the carotid siphon (proximal or distal to the origin of the ophthalmic artery) of at least 60% reduction in lumen diameter showed a reduction of the relative end-diastolic flow velocity (modified Pourcelot's index) of more than 40%; additionally, stenoses proximal to the origin of the ophthalmic artery exhibited a variable alternating flow, or flow reversal, in the supratrochlear artery. Stenoses distal to the origin of the ophthalmic artery rarely revealed the theoretically expected increase in orthograde flow velocity in the supratrochlear artery. Stenoses of the middle cerebral artery consisting of more than atherosclerotic irregularities proved to be an exception. Supraclinoid occlusions of the internal carotid artery were reliably demonstrated by Doppler sonography. However, the majority of acute occlusions of the middle cerebral artery could not be detected by this means, probably due to anastomoses between the anterior and the middle cerebral arteries, which were detected by angiography. Thus, we believe that c-w Doppler sonography is a reliable tool to detect stenoses of the carotid siphon of more than 60% reduction in lumen diameter and supraclinoid carotid artery occlusions. Barriers to the cerebral blood flow located more peripherally cannot be diagnosed reliably with this technique.
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  • 7
    ISSN: 1432-1920
    Keywords: Doppler sonography ; basilar artery occlusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have investigated 6,972 patients with directional continuous-wave Doppler sonography within the last three and a half years, and have derived criteria for the sonographic diagnosis of basilar artery occlusion or tight stenosis in conjunction with 1,071 retrograde brachial angiograms. By sonographic patterns, we have suspected obstruction of the basilar artery or of both distal vertebral arteries in nine cases. Either bilateral sonographic silence or the absence of a diastolic flow component of the vertebral arteries served as criteria in the sonographic evaluation. Angiography of the vertebro-basilar system, performed in eight cases, showed near or complete occlusion in the distal vertebrals or in the proximal basilar artery. Degrees of stenosis less than an 80 percent reduction in lumen diameter could not be detected sonographically. Two further basilar artery occlusions were detected by means of angiography despite negative Doppler sonography: one of these patients showed an extensive collateral circulation between the posterior inferior and the superior cerebellar arteries, and one patient had an occlusion only of the middle and rostral thirds of the basilar artery, the proximal third and the anterior inferior cerebellar arteries being widely patent. Thus, we believe that directional CW Doppler sonography is very useful in the diagnosis of near or complete occlusion of both distal vertebral arteries or of the proximal basilar artery.
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  • 8
    ISSN: 1432-1920
    Keywords: C-w Doppler sonography ; EC-IC anastomoses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report the results obtained by means of directional c-w Doppler sonography on 33 patients with superficial temporal-to-middle cerebral artery anastomoses. The efficiency of the anastomosis was evaluated by the modified Pourcelot indices (relative end-diastolic flow velocities) of the preauricular superficial temporal artery and of the bypass-supplying branch at the edge of the burr-hole. The influence of intermittent compression of the bypass-supplying branch on the modified Pourcelot index of the ipsilateral common carotid was used as a further criterion in the sonographic evaluation. All efficient anastomoses, defined by a modified Pourcelot index of at least 0.20 at the edge of the burr-hole, exhibited a reduction of the relative end-diastolic flow velocity of 0.08 on the average in the common carotid during compression. In the 18 cases with unilateral occlusion of the internal carotid, bypass surgery was predominantly efficacious in those patients who showed a reduction in the sum of the modified Pourcelot indices of the remaining brain-supplying arteries of at least two standard deviations with respect to the mean of age-matched controls. The subgroups of patent and absent collaterals through the ophthalmic artery did not show any difference with respect to the percentage of efficient anastomoses. In all 4 patients with bilateral internal carotid artery occlusion, bypass surgery was effective, while 50% of the patients with intracranial carotid artery disease exhibited an insufficient anastomosis. The 2 patients with a stenosis or an occlusion of the M-1 segment of the middle cerebral artery showed modified Pourcelot indices of the anastomosis-supplying branch of 0.45 and 0.46 at the edge of the burr-hole, respectively. Thus, we believe that the efficiency of a superficial temporal-to-middle cerebral artery anastomosis can be evaluated semiquantitatively by directional c-w Doppler sonography. The preoperatively calculated sum of the modified Pourcelot indices of the remaining brain-supplying arteries can be used as an additional criterion for the evaluation of the necessity of bypass surgery, at least in cases of unilateral and bilateral internal carotid occlusions.
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