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The key factors that will influence the outcome of a patient with acute ischemic stroke are the time it takes to reopen the vessel (from the stroke onset time), the patient’s individual intracranial hemodynamics and inherent collateral flow, the viable tissue that is still left (penumbra), and the effectiveness of stoke treatment and intervention (Fig. 8.1 ). Imaging is useful in all these aspects.

Computational models of myocardial perfusion in normal as well as pathological conditions have contributed to recent advances in the personalized diagnosis and treatment of cardiovascular disease.. For the coronary circulation we attempt to develop a vascular tree model based on realistic replicas from the intramural vessels in hearts from animals and man. These virtual replicas are obtained by means of a novel imaging cryomicrotome producing a stack of 4000 images of 2000x2000 pixels. This paper describes the methods developed for segmentation of the images resulting in a 3D virtual vascular model. Also the methods for fluorescent microsphere detection are described used to validate the models in prediction of flow distribution over the walls of the heart chambers. Special attention is provided to the detection of collaterals and collateral flow.

In 1986, Murry and colleagues made the seminal observation that brief episodes of myocardial ischemia—too brief in themselves to cause myocyte death—paradoxically rendered the previously ischemic myocardium more resistant to a subsequent sustained period of coronary artery occlusion.1 This first report of “preconditioning with ischemia” in the anesthetized dog was soon duplicated by others using similar canine preparations,2–4 and confirmed by numerous investigators to occur in other species including the rat,5,6 rabbit7–9 and pig.10,11 As a result, there is unprecedented agreement among investigators and laboratories world-wide that ischemic preconditioning profoundly limits myocardial infarct size. However, the question which, to date, remains unanswered is: precisely how does brief ischemia protect the myocytes from a later episode of sustained coronary occlusion?

The purpose of the microvascular anastomosis between an extracranial and a cortical arterial vessel (2, 8) is to supply additional collateral blood flow to an ischemic cortical region of the brain. A major benefit may be derived from the by-pass in preventing or postponing further ischemic lesions and improving local blood flow. Based on our own clinical material the attempt is made in this study, to assess the therapeutic effect of this operation.

When coronary arteriograms are evaluated with a view to performing coronary angioplasty, some angiographic features need special attention. As coronary angioplasty is an attempt at “direct” treatment of coronary stenoses through transluminal access, the course and the condition of the coronary vascular bed proximal and distal to the stenosis and the morphology of the coronary stenosis are important for assessment of feasibility of the procedure and the risk of coronary vascular complications. Localization of coronary stenosis and distribution of the PTCA vessel distal to the obstruction largely determine the clinical consequences for the patient should total occlusion of the PTCA vessel occur. Both the presence or absence of angiographically visible collateral flow to or originating from the PTCA vessel and the status of the left ventricle can also influence the selection process with respect to dilatation strategy and patient safety.

The application of the intraaortic balloon counter pulsation (IABP) has become a standard therapy in patients with cardiogenic shock or in cases of low cardiac output postoperatively. Experimental results to show a reduction of the infarct size due to the IABP are contradictory (6, 9–12). The aim of this study is to find out if an acute evolving myocardial infarction can be reduced in size by the IABP.

The coronary artery tree is classically divided into three vessel systems and patients are categorised according to lesions involving 50% or more reduction of lumen diameter in the branches of these systems — thus, heart patients are described as having one-, two- or three-vessel disease. There are, however, a number of major branches in the coronary circulation and it is, for instance, often possible to perform coronary bypass surgery on a number of terminal vessels in each of the coronary systems. Each of these individual vessels is important and has to be evaluated if the extent of disease is to be accurately described. Furthermore, the effects of multiple stenoses are probably more than additive, so attention to only the severest stenosis does not give an adequate representation of the reduction of myocardial blood flow, one of the critical factors in determining the symptoms of ischaemic heart disease. A second critical factor is the amount of myocardium prejudiced by stenosis, which must determine the outcome of sudden events such as infarction resulting from changes related to that stenosis. These factors are to a variable extent ameliorated by collateral blood flow. It is very important, therefore, to take all of them into account when assessing the coronary circulation.

The rationale behind extra-intracranial arterial bypass (EIAB), developed and successfully applied to an inaccessible regional vascular obstructive lesion by DONAGHY and YASARGIL in 1966/67, is augmentation, of collateral blood flow to the brain (11, 12). This may ameliorate ischemic neurologic deficit and reduce the incidence of stroke or recurrent stroke. With the help of EIAB a prophylactic collateral blood supply can be established in order to allow therapeutic occlusion of a major intracranial vessel.

Many late follow-up studies after extra-intracranial (EC/IC) bypass have been performed recently (2, 4–6, 8, 11–15, 18), all of them based on results from cases ranging in number from 46 (18) to 100 (6). Here we report on 119 EC/IC bypass patients whose outcome was assessed both clinically and by (repeated) angiography.

Two advances in the last decade have made a major impact on coronary arteriography, namely, the introduction of the caesium iodide image intensifiers and the routine use of caudo-cranial (cranial) and cranio-caudal (caudal) angled projections [1–11].

Relief from angina pectoris, i.e. improvement of myocardial ischemia by means of medication, can be achieved in at least two ways: 1. by reducing the oxygen demand of the myocardium in general, thereby lessening the need for an increase in flow in the poststenotic, potentially ischemic areas of the myocardium, and 2. by increasing flow, mainly collateral flow to the ischemic area.