This chapter discusses the basic ethical principles and practices for human experimentation. It touches on the related subject of regulatory and legal issues in neurological research. Disorders of the central nervous system (CNS) present a number of challenges for specifying core principles and practices of research ethics. In CNS research, the tensions between regulation and ethics are greatest around the use of placebo controls. Phase 1 trials of new CNS interventions, as with all interventions, generally present a high degree of risk and uncertainty. Many trials involving neurological disorders show evidence of placebo responses. Many CNS drug trials involve brain imaging, in one report, brain abnormalities, like malignancies or vascular malformations, were detected in as many as 18% of healthy volunteers. Issues of justice arise with particular frequency whenever CNS trials involve placebos. Researchers should also attend to various non-verbal or affective elements of communication that shape public expectations.

Computerized tomography scans are rapid, readily available, and relatively inexpensive. Volume of hemorrhage on computerized tomography (CT) is an important predictor of mortality and functional ability after intracerebral hemorrhage (ICH). Computerized tomography angiography (CTA) offers many clinical advantages over cerebral digital subtraction angiography (DSA) for the evaluation of intracranial vascular abnormalities in cases of ICH. CTA must be shown to have similar sensitivity and specificity as DSA in the detection of secondary causes of ICH. The use of non-contrast CT in the initial evaluation of patients presenting with suspected ICH is well established and universally accepted. Recently, advances in CTA have enabled this modality to gain wide acceptance in evaluating possible secondary causes of ICH, such as aneurysm or vascular malformation. As scanner technology and software rendering capabilities continue to improve, CTA appears poised to replace DSA and become the new gold standard for such evaluations.

This chapter reviews the evidence that blood is readily identifiable on magnetic resonance imaging (MRI). It describes how the use of multiple sequences provides additional information regarding the age of blood products. MRI signal changes on gradient recalled echo (GRE), T1- and T2-weighted images can be used to estimate the age of intracranial blood. MRI is the initial diagnostic procedure of choice for investigation of underlying structural causes of secondary intracerebral hemorrhage (ICH), including vascular malformations and neoplasms. It is generally recognized that MRI is superior to computed tomography (CT) in the evaluation of subarachnoid space diseases of an inflammatory or neoplastic origin. The existence and nature of the penumbra in ICH is arguably the most pressing outstanding information required by clinicians to make rational management decisions in ICH patients. MRI is a valuable tool for investigating the pathophysiology of acute and chronic ICH.

Vascular malformations constitute an important cause of intracranial hemorrhage especially in younger patients. These malformations may arise from any segment of the different functional units of the brain vasculature, including arteries, arterioles, capillaries, venules, and veins. Among vascular malformations causing intracranial hemorrhage, brain arteriovenous malformations (AVMs) are among the most frequently encountered. Brain AVMs commonly affect distal arterial branches and in roughly half of the cases, the malformation is found in the borderzone region shared by the distal anterior, middle, and/or posterior cerebral arteries. Cerebral angiography may help to differentiate brain AVMs from other types of intracranial anomalies with arterio-venous shunting. Resection of an associated developmental venous anomaly is contraindicated as its occlusion may lead to venous stasis, brain edema, and eventual hemorrhage. A developmental venous anomaly (DVA) is found in up to 30% of cerebral cavernous malformations (CCM) patients.