Early infarct

Several studies have validated the ability of CTP to distinguish between core and penumbra. In one study, Wintermark et al. found that the volumes of early infarcts in CTP CBV maps were highly correlated with volumes of early DWI lesions, whereas volumes of lesions seen in CTP CBF maps were close to those seen in the corresponding MRP MTT maps. In another study, the volume of the CBF abnormahty in an acute-stage infarct was highly correlated with final infarct volume in patients who did not exhibit recanalization after thrombolysis, consistent with extension of infarction into the penumbra. However, in patients who did exhibit recanalization after thrombolysis, final infarct volume was highly correlated with the initial CBV abnormality, consistent with failure of infarcts to extend into the ischemic penumbra. ... 

Wong CK, French JK, Krucoff MW, Gao W, Aylward PE, White HD. Slowed ST segment recovery despite early infarct artery patency in patients with Q waves at presentation with a first acute myocardial infarction implications of initial Q waves on myocyte reperfusion. Eur Heart J 2002b 23(18) 1449. 

ECASS /-// and ATLANTIS A-B trials The European Cooperative Acute Stroke Study (ECASS-I) enrolled 620 patients with acute ischemic stroke in whom treatment could be initiated within 6 h of stroke onset [42]. Patients were excluded if pretreatment CT showed signs of hemorrhage or major early infarction involving more than one-third of the MCA territory (diffuse sulcal effacement, poor differentiation between gray-white matter, and diffuse hypodensity). In a randomized double-blind study, patients either received placebo or IV t-PA (1.1 mg/kg to a maximum dose 100 mg 10% bolus followed by infusion over 1 h) and could not receive anticoagulants, antiplatelet, cerebroprotective. 

Keywords— Color, Early infarct, Hounsfield units. Ischemic stroke. Training system. 

The visualization of early stroke area represented by red (2) color is greatly improved with the help of proposed color map. Besides, the proposed color image also enables medical practitioners to pay full attention on suspected infarct area represented by red color in the brain image. Meanwhile, the detection of early infarct area is not solely based on spotting for red color region, but rather comparing the color symmetrically in brain image. With the help of color, medical practitioners will he even more difficult to miss out old infarct represented hy hlack color. Fig. 2 shows the early infarct area. 

Fig. 1 CT brain image of early infarct (a) Image before windowing process and (b) grayscale image after undergoing convorsion process...

Fig. 2 CT brain image of early infarct case, (a) Early infarct area indicated by a circle, (b) Early infarct area is represented by ted color...

Table 2 exhibits the scores of the evaluation on students without medical background. The result shows that the proposed method has improved the scores by 3.7%. As a result, the proposed method is proven to be helpful to enable students making accurate diagnosis for early infarct area. Meanwhile, there is also an improvement on scores from students with medical background. The improvement is achieved by 6.1% as tabulated in Table 3. 

It is well accepted that hypertension is a multifactorial disease. Only about 10% of the hypertensive patients have secondary hypertension for which causes, ie, partial coarctation of the renal artery, pheochromacytoma, aldosteronism, hormonal imbalances, etc, are known. The hallmark of hypertension is an abnormally elevated total peripheral resistance. In most patients hypertension produces no serious symptoms particularly in the early phase of the disease. This is why hypertension is called a silent killer. However, prolonged suffering of high arterial blood pressure leads to end organ damage, causing stroke, myocardial infarction, and heart failure, etc. Adequate treatment of hypertension has been proven to decrease the incidence of cardiovascular morbidity and mortaUty and therefore prolong life (176—183). 

Several clinical trials have been conducted with streptokinase adrninistered either intravenously or by direct infusion into a catheterized coronary artery. The results from 33 randomized trials conducted between 1959 and 1984 have been examined (75), and show a significant decrease in mortaUty rate (15.4%) in enzyme-treated patients vs matched controls (19.2%). These results correlate well with an ItaUan study encompassing 11,806 patients (76), in which the overall reduction in mortaUty was 19% in the streptokinase-treated group, ie, 1.5 million units adrninistered intravenously, compared with placebo-treated controls. The trial also shows that a delay in the initiation of treatment over six hours after the onset of symptoms nullifies any benefit from this type of thrombolytic therapy. Conversely, patients treated within one hour from the onset of symptoms had a remarkable decrease in mortaUty (47%). The benefits of streptokinase therapy, especially in the latter group of patients, was stiU evident in a one-year foUow-up (77). In addition to reducing mortahty rate, there was an improvement in left ventricular function and a reduction in the size of infarction. Thus early treatment with streptokinase is essential. 

However, already in an early clinical trial, rofecoxib was found to produce four times the number of myocardial infarctions than its comparator drug, naproxen. A subsequent trial of rofecoxib compared to placebo in colorectal cancer prevention demonstrated, after 18 months of study, that a greater number of myocardial infarctions occulted in the rofecoxib group. In 2004 the manufacturers of rofecoxib withdrew the diug from the market. A similar study of celecoxib compared to placebo in cancer prevention, showed that celecoxib also increased the risk of cardiovascular embolisms [3]. 

In most cases, the ultimate volume of an infarct is larger than that seen in initial DWI images,encompassing both initially DWI-abnormal tissue and other tissue into which the infarct extends. The ultimate volume of an infarct also is usually larger than that seen in early CBV maps. However, DWI images rather than CBV maps are usually used to identify the infarct core, both because infarcts are usually far more conspicuous in DWI images than in CBV maps, and because the DWI detects lesions that have been irreversibly damaged despite... 

FIGURE 2.11 Matched diffusion and perfusion abnormalities. An early DWI image (a) shows an acute infarct in the left thalamus. An MTT map (b) shows a small perfusion abnormality that is no larger than the diffusion abnormality. When diffusion and perfusion lesions are matched, there is usually minimal if any infarct extension. Indeed, in this case, a follow-up CT scan (c) shows no enlargement of the infarct. 

Wardlaw JM, Dorman PJ, Lewis SC, Sandercock PAG. Can stroke physicians and neuroradiologists identify signs of early cerebral infarction on CT J Neurol Neurosurg Psychiatry 1999 67 651-653. 

Fiorelli M, Bastianello S, von Kummer R, del Zoppo GJ, Larrue V, Lesaffre E, Ringleb AP, Lorenzano S, Manelfe C, Bozzao L. Hemorrhagic transformation within 36 hours of a cerebral infarct Relationships with early clinical deterioration and 3-month outcome in the european cooperative acute stroke study i (ECASS i) cohort. Stroke. 1999 30 2280-2284. 

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