Infarct size/volume

Curry et al. Neurosurgery 2005 56(4) 681-692 Retrospective chart, operative report, and imaging review 38 patients treated with hemicraniectomy for large hemispheric infarcts (average volume 407 cm ) Survival and surgical selection of patients 32 patients survived at 1 year. Age but not time to surgery, volume of infarction or craniectomy size correlated with ability to walk and Barthel score... 

The proposal that NO or its reactant products mediate toxicity in the brain remains controversial in part because of the use of non-selective agents such as those listed above that block NO formation in neuronal, glial, and vascular compartments. Nevertheless, a major area of research has been into the potential role of NO in neuronal excitotoxicity. Functional deficits following cerebral ischaemia are consistently reduced by blockers of NOS and in mutant mice deficient in NOS activity, infarct volumes were significantly smaller one to three days after cerebral artery occlusion, and the neurological deficits were less than those in normal mice. Changes in blood flow or vascular anatomy did not account for these differences. By contrast, infarct size in the mutant became larger... 

Fig. 1. BEO dose-dependently reduces infarct size after permanent MCAo. Representative images of brain sections from (A) rats in — 5) sacrificed 24 h after permanent occlusion of middle cerebral artery (24 h MCAo) and (B) BEO-treated rats (n — 5) prior to MCAo BEO (0.5 ml/kg) was administered i.p. 1 h before MCAo. Brain sections were stained by TTC the ischemic region appears as a pale-stained area whereas the viable tissue is stained red. (C) Effects of different doses of BEO (0.05—1 ml/kg), administered i.p. 1 h before MCAo, on infarct volume results are expressed as mean S.E.M. (n = 4-6 per group). and Denote P< 0.05 andP< 0.01 versus 24 h MCAo, respectively (ANOVA followed by Dunnett multiple comparisons test).

TIA-related infarctions on DWI are often very small (Ay et al. 2002 Kidwell et al. 1999 Rovira et al. 2002). As mentioned before, 96% of infarctions on DWI are smaller than 1 ml in volume. The mean infarction load (total volume of all acute infarctions if there are multiple) on DWI has been reported to be 1.5+1.8 ml (Ay et al. 2005). An infarction load of less than 1.8 ml is associated with reversible clinical deficit within 24 h with 79% sensitivity and 78% specificity. Two other DWI studies have produced similar results. Ay et al. (2002) found that the infarction size was less than 15 mm in diameter in 85% of 27 TIA patients with infarction identified by DWI, of which 83% were punctate (< 5 mm). Rovira et al. (2002) estimated TIA-related infarctions range from 2 to 40 mm in diameter (mean, 15 mm). Figures 12.3 and 12.4 present examples of small hyperintense lesions on DWI that represent the remnants or footprints of a recent ischemia. 

Frazzini et al., 1994 Wistar rats MCAo Permanent 33 and 37, intraischemia, with or without MK-801 before or after ischemia Infarct volume 24 h postischemia Both hypothermia and MK-801 reduced infarct size no further reduction when combined... 

Onesti et al., 1991 SH rats MCAo Permanent 24 and 36, intraischemia and 1 h postischemia Infarct volume 24 h postischemia Reduced infarct size... 

Burns RJ, Gibbons RJ, Yi Q, et al. The relationships of left ventricular ejection fraction, end-systolic volume index and infarct size to six-month mortality after hospital discharge following myocardial infarction treated by thrombolysis. J Am... 

WuE, Ortiz JT, Tejedor P, et al. Infarct size by contrast enhanced cardiac magnetic resonance is a stronger predictor of outcomes than left ventricular ejection fraction or end-systolic volume index prospective cohort study. Heart 2008 94(6) 730—6. 

Roes SD, Kelle S, Kaandorp TAM, et al. Comparison of myocardial infarct size assessed with contrast-enhanced magnetic resonance imaging and left ventricular function and volumes to predict mortality in patients with healed myocardial infarction. Am J Cardiol 2007 100(6) 930-6. 

An early report from our group indicated that, in the absence of early recanalization, CTA-Sl typically defines minimal final infarct size and, hence, like DWI and thresholded CBF maps (Fig.5.5, 5.6), can be used to identify infarct core in the acute setting [34] (Figs. 5.5, 5.6). Coregistration and subtraction of the conventional, unenhanced CT brain images from the axial, post contrast CTA source images should result in quantitative blood volume maps of the entire brain [15, 27, 70]. CTA-SI subtraction maps, obtained by coregistration and subtraction of the unenhanced head CT... 

In another study, CTA-SI preceding DWI imaging was performed in 48 consecutive patients with clinically suspected stroke, presenting within 12 h of symptom onset (42 patients within 6 h) [24]. CTA-SI and DWI lesion volumes were independent predictors of final infarct volume, and overall sensitivity and specificity for parenchymal stroke detection were 16% and 90% for CTA-SI, and 100% and 100% for DWI, respectively. When cases with initial DWI lesion volume <15 mL (small lacunar and distal infarctions) were excluded from analysis, CTA-SI sensitivity and specificity increased to 95% and 100%, respectively. Although DWI is more sensitive than CTA-SI for parenchymal stroke detection of small lesions (Fig. 5.7), both DWI and CTA-SI are highly accurate predictors of final infarct volume. DWI tends to underestimate final infarct size, whereas CTA-SI more closely approximates final infarct size, despite the bias towards DWI being obtained after the CTA-SI in this cohort of patients with unknown recanalization status. 

Mehta, N., et al. Prediction of final infarct size in acute stroke using cerebral blood flow/cerebral blood volume mismatch added value of quantitative first pass CT perfusion imaging in successfully treated versus unsuccessfully treated/untreated patients, in Proceedings of the 41st Annual Meeting of the American Society of Neuroradiology. 

Studies using various imaging modalities (Xe-enhanced CT, MRI DWI, CTA source images, and CTP) have demonstrated that pretreatment core infarct size predicts the clinical response to reperfusion, and that core infarct volume less than 70-100 mL may be an effective treatment target... 

In their theoretical studies, Bogen et al (1980) assumed an initially spherical membrane model for the infarcted LV. Employing a finite element method, it was possible to obtain end diastolic and end systolic pressure-volume curves. From these P-V curves, the effects of infarct size and infarct stiffness on the... 

Figure 14 displays the relationships between stroke volume (relative to the stroke volume in the normal ventricle) and infarct size for various values of infarct stiffness. For EDP = 12mmHg, the percentage decrease in stroke volume exceeds the percentage of myocardial infarction e.g. a 41% infarct reduces function to levels of 48% and 28% of normal depending on the infarct stiffness. 

Figure 14. Stroke volume versus infarct size relationships for various infarct stiffnesses. The percentage decrease in stroke volume exceeds the percentage of myocardial infarction. (Reproduced from Bogen et al. An analysis of the mechanical disadvantage of myocardial infarction in the canine left ventricle, Circ Res 47 728,1980 with permission of the American Heart Association.)...

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