Transcranial duplex imaging with a sulfurhexafluoride echocontrast agent: enhancement and diagnostic quality.

BACKGROUND AND PURPOSE: The authors investigate characteristics of ultrasound enhancement and diagnostic quality of a sulfurhexafluorides (SF6)-containing echocontrast agent (SonoVue) in cerebrovascular patients with insufficient temporal bone window by transcranial color-coded duplex (TCCD) sonography. METHODS: Thirty patients (mean age = 62.2 +/- 11.1 years) were enrolled. SF6 was administered intravenously in 4 different doses (0.3, 0.6, 1.2, and 2.4 mL). By videotape analysis, time to contrast appearance, duration of contrast enhancement, and duration of clinically useful signal enhancement were measured. Overall quality of ultrasound investigation was also assessed. RESULTS: Time to contrast appearance ranged from 11 to 74 seconds (mean = 26 seconds). For the 0.3, 0.6, 1.2, and 2.4 mL doses, average times to contrast appearance of 30 +/- 12 seconds, 28 +/- 10 seconds, 23 +/- 8 seconds, and 22 +/- 6 seconds were measured. Duration of TCCD signal enhancement was 438 +/- 169 seconds, 483 +/- 195 seconds, 713 +/- 299 seconds, and 788 +/- 344 seconds for the different doses. Clinically useful enhancement was 160 +/- 124 seconds, 200 +/- 157 seconds, 260 +/- 166 seconds, and 327 +/- 239 seconds. CONCLUSIONS: Administration of SonoVue led to a quality improvement in 21 patients. In TCCD, it optimizes visualization of the cerebral arteries in patients with inadequate bone window. A dose of at least 1.2 mL provides the best enhanced images.

A new model of chronic cardiac ischemia in rabbits.

Chronic cardiac ischemia has mainly been studied in large species such as pigs or dogs. Little research has been performed using small species such as rabbits. In the present study, 1-3 wk after implantation of a novel device (ameroid) on the circumflex coronary artery of New Zealand White rabbits, vessel patency was evaluated by coronary angiography, corrosion cast, and radiolabeled microspheres. Coronary angiograms showed, after 21 days, either total occlusion or severe stenosis in seven of eight arteries, which was confirmed by corrosion casts. The ameroid group had less blood flow in the epicardial (-62%) and endocardial (-54%) layers of the ischemic area compared with sham-operated rabbits (P < 0.05). Blood flow increased in the ischemic area compared with day 0 during acute occlusion, suggesting that progressive coronary occlusion initiated the growth of de novo collateral vessels. Thus we have developed a new model of chronic cardiac ischemia in rabbits with documented progressive coronary stenosis and occlusion that is suitable to test various therapeutic angiogenesis strategies.

[Area reduction in carotid stenosis of the internal carotid artery]. / Querschnittsflächenreduktion bei A.-carotis-interna-Stenose. Bestimmung mit intensitätsgewichteter farbkodierter Duplexonographie.

AIM: In patients with atherosclerotic extracranial internal carotid artery (ICA-) stenosis the diagnostic value of colour Doppler energy (CDE)-coded duplexsonography was compared to three other methods: continuous wave (cw) Doppler peak systolic frequency (pF), pulsed wave (pw) Doppler peak systolic velocity (pV), and intraarterial digital subtraction angiography. METHODS: In 58 patients who suffered from 60 moderate to severe ICA stenoses, B-mode sonography combined with CDE-coded duplex sonography was applied to measure the extent of the stenosis by determining the residual lumen width. Results were correlated to pF and pV and with various angiographic indices. RESULTS: The determined values of the degree of stenosis were correlated to the measurement of pV (r = 0.441, p < 0.01), but not to pF (r = 0.122, n.s.). The best correlation to angiography was obtained when the linear ICA diameter was compared to the distal common carotid artery (common carotid artery index) (r = 0.214, n.s.). Sensitivity, specificity and diagnostic accuracy were comparable to the different frequency-based measurements, but the positive predictive value was lower. CONCLUSIONS: Determination of the degree of stenosis based on CDE alone is not reliable enough to allow correct diagnosis of severe carotid artery stenosis. In combination with the peak frequency method is's diagnostic value could be improved. This requires verification in a separate study.

[Intensive monitoring of patients with acute cerebral ischemia within the scope of a coordinated stroke treatment concept: initial experiences]. / Intensivmedizinische Uberwachung von Patienten mit akuter zerebraler Ischämie im Rahmen eines koordinierten Hirnschlagbehandlungskonzepts: erste Erfahrungen.

QUESTIONS UNDER STUDY: It has been shown that the prognosis of patients with stroke can be improved by specialized stroke units. Whether any additional benefit can be achieved by use of intensive care resources is unknown. Therefore, it was the purpose of this study to analyze our first experience of management of patients with acute ischaemic stroke in an intensive care unit, as part of a newly implemented coordinated stroke concept. METHODS: A consecutive series of 88 patients with acute ischemic stroke (age 64.4 +/- 14.2 years, 28% females) hospitalized in a medical intensive care unit according to predefined criteria formed the study population. The goals were to monitor vital functions, to complete diagnostic studies in timely fashion and to prevent and treat complications. RESULTS: The patients were hospitalized in the intensive care unit for a mean period of 34.4 +/- 19.5 hours. Relevant pathologic findings included systolic hypertension > 220 mm Hg in 5% and permanent or intermittent relative systolic hypotension < 150 mm Hg in 25% and 98% of patients respectively. One patient (1%) died during the stay. Additional diagnostic studies were performed more often in patients with progressive or fluctuating symptoms (100% of patients in each group) than in those with improving or stable symptoms (50% of patients in each group). Fourteen percent of patients were treated for hypertension and 30% for hypotension. Antithrombotic therapy with aspirin was started in 34%, prophylaxis for venous thrombosis with low dose heparin in 39% and systemic anticoagulation in 40% of patients respectively. No cardiac or pulmonary complications requiring treatment were observed and no specific therapies for neurologic complications were utilized. At the time of discharge from the intensive care unit, 88% of patients showed improved or stable neurologic findings. CONCLUSIONS: In the present analysis, an unexpectedly high incidence of relative arterial hypotension was observed in patients hospitalized in an intensive care unit for acute ischaemic stroke. Therapeutic measures were restricted mainly to blood pressure control and anticoagulation/antithrombotic treatment. Specific therapies for neurologic complications or interventions requiring the resources of an intensive care unit were not used. Whether defined patient groups with ischaemic stroke will benefit from specific treatment in an intensive care unit needs to be tested by controlled, randomized studies.