[Quality parameters in the treatment of acute stroke: comparison of various regional treatment concepts]. / Qualitätsparameter der akuten Schlaganfallversorgung: Gegenüberstellung unterschiedlicher regionaler Versorgungskonzepte.

BACKGROUND: The long-term prognosis of stroke patients is still dependent in particular on the timing of a correct diagnosis, immediate initiation of a suitable specific therapy and competent treatment in a stroke unit. Therefore, nationwide attempts are being made to establish a comprehensive coverage of the necessary specific competence and infrastructural requirements. Divergent regional circumstances and economic viewpoints determine the characteristics of the various healthcare concepts and the interplay between participating cooperation partners. This article compares the development with respect to three qualitative treatment parameters exemplified by four regional healthcare models during the time period 2008-2011. METHODS: The hospitalization rates for patients with transitory ischemic attacks, ischemic and hemorrhagic stroke, the case numbers for stoke unit treatment and the rates of systemic thrombolysis and mechanical thrombectomy in the regions of Berlin, the Ruhr Area, Ostwestfalen-Lippe and southeast Bayern (TEMPiS) are presented based on the data from the DRG statistical reports for the years 2008 and 2011. RESULTS: The average hospitalization rates for ischemic stroke patients (brain infarct ICD 163) in the time period from 2008 to 2011 were 294 per 100,000 inhabitants for the Ruhr Area, 257 per 100,000 inhabitants for Ostwestfalen-Lippe and 265 per 100,000 inhabitants each for Berlin and southeast Bayern. The complex stroke treatment quota for southeast Bayern in 2008 was 31 % and 47 % in 2011 and the respective quotas for the other regions studied were 42-44 % and 58-59 %. The rate of systemic thrombolysis in 2008 ranged between 4.2 % and 7.4 % and in 2011 the increase in the range for the 4 regions studied was between 41 % and 145 %. In 2011 the thrombectomy quota of 2 % in the Ruhr Area was the only one which was above the national average of 1.3 % of all brain infarcts. DISCUSSION: Stroke is a common disease in the four regions studied. For the established forms of therapy, complex treatment of stroke and systemic thrombolysis, the positive effect of structurally improved approaches in the four different regional treatment concepts could be confirmed during the course of the observational time period selected. Mechanical thrombectomy which is currently still considered to be an individual healing attempt, was used significantly more often in the Ruhr Area in 2011 than in the other three regions studied. A standardized referral procedure had previously been established in the metropolitan regions.

Contrast agent specific imaging modes for the ultrasonic assessment of parenchymal cerebral echo contrast enhancement.

Previous work has demonstrated that cerebral echo contrast enhancement can be assessed by means of transcranial ultrasound using transient response second harmonic imaging (HI). The current study was designed to explore possible advantages of two new contrast agent specific imaging modes, contrast burst imaging (CBI) and time variance imaging (TVI), that are based on the detection of destruction or splitting of microbubbles caused by ultrasound in comparison with contrast harmonic imaging (CHI), which is a broadband phase-inversion-based implementation of HI. Nine healthy individuals with adequate acoustic temporal bone windows were included in the study. Contrast harmonic imaging, CBI, and TVI examinations were performed in an axial diencephalic plane of section after an intravenous bolus injection of 4 g galactose-based microbubble suspension in a concentration of 400 mg/mL. Using time-intensity curves, peak intensities and times-to peak-intensity (TPIs) were calculated off-line in anterior and posterior parts of the thalamus, in the region of the lentiform nucleus, and in the white matter. The potential of the different techniques to visualize cerebral contrast enhancement in different brain areas was compared. All techniques produced accurate cerebral contrast enhancement in the majority of investigated brain areas. Contrast harmonic imaging visualized signal increase in 28 of 36 regions of interest (ROIs). In comparison, TVI and CBI examinations were successful in 32 and 35 investigations, respectively. In CHI examinations, contrast enhancement was most difficult to visualize in posterior parts of the thalamus (6 of 9) and the lentiform nucleus (6 of 9). In TVI examinations, anterior parts of the thalamus showed signal increase in only 6 of 9 examinations. For all investigated imaging modes, PIs and TPIs in different ROIs did not differ significantly, except that TVI demonstrated significantly higher PIs in the lentiform nucleus as compared with the thalamus and the white matter (P < 0.05). The current study demonstrates for the first time that CBI and TVI represent new ultrasonic tools that allow noninvasive assessment of focal cerebral contrast enhancement and that CBI and TVI improve diagnostic sensitivity as compared with CHI.

Transient response harmonic imaging: an ultrasound technique related to brain perfusion.

BACKGROUND AND PURPOSE: Gray-scale harmonic imaging is the first method to visualize blood perfusion and capillary blood flow with ultrasound after intravenous contrast agent application. The purpose of the present study was to evaluate the potential of transient response second harmonic imaging (TRsHI) to assess normal echo contrast characteristics in different brain areas by transcranial ultrasound. METHODS: In 18 patients without cerebrovascular diseases, TRsHI examinations were performed bilaterally with the use of the transtemporal approach after application of 6.5 mL of a galactose-based microbubble suspension (400 mg/mL). The transmission rate was once every 4 cardiac cycles. Regional cerebral contrast was visually assessed and then quantified off-line with the use of time-intensity curves. In 4 different regions of interest (ROI) (posterior part of the thalamus [ROIa], anterior part of the thalamus [ROIb], lentiform nucleus [ROIc], and white matter [ROId]), the following parameters were evaluated: peak intensity, area under the curve (AUC), and time to peak intensity. AUC ratios for ROIc/a, d/a, c/b, and d/b were calculated. RESULTS: In all patients parenchymal contrast enhancement was visually detectable. One hundred thirty-one characteristic time-intensity curves (baseline phase, peak contrast intensity, slow washout phase) were demonstrable in 144 ROIs. In ROIc and ROId, characteristic contrast curves could be observed most frequently (68/72 examinations), whereas time-intensity curves in ROIa and ROIb could not be evaluated because of inadequate contrast enhancement in 9 of 72 examinations. Time to peak intensity varied between 20 and 52 cardiac cycles; in 1 patient it was 88 cardiac cycles. In all individuals AUCs and in 16 of 18 subjects peak intensity in ROIc and ROId showed a 2- to 10-fold increase compared with ROIa and ROIb. In no examination did AUC ratios show a >2-fold side difference irrespective of the ROI. CONCLUSIONS: The present study demonstrates for the first time that TRsHI produces accurate contrast in different brain areas and represents an ultrasonic tool related to brain perfusion. Absolute values of quantitative parameters show high variations caused by different temporal bone thicknesses and a complex relationship between echo contrast concentrations and measurements of optic intensities. Ratios between different ROIs help to compare contrast enhancement in different brain areas. Furthermore, because of the fact that attenuation of contrast enhancement in TRsHI depends strictly on the insonation depth, harmonic imaging studies of brain perfusion cannot be compared directly with other imaging techniques such as positron emission tomography.