oa Editorial

Functional imaging with various radioligands and single photon emission tomography (SPECT) or positron emission tomography (PET) has demonstrated many types of blood flow, glucose metabolic and neurochemical dysfunctions in a variety of neurological disorders. Functional neurotransmitter imaging is an evolving technique to detect neurotransmittersreleased during a task performance. Dr. Alan Fischman reports striatal and extrastriataldopamine neurotransmission during performance of a variety of cognitive and behavioral tasks. Dr. Biswas describes the role of SPECT and magnetic resonance imaging (MRI) for pre- and postoperative evaluation of childhood Moyamoya disease, which is characterized by chronic progressive stenosis leading to occulusion of carotid as well as anterior and middle carotid arteries. Imaging presynaptic dopaminergic markers provides key insights into the pathophysiology of Parkinson's disease (PD), which is characterized by bradykinesia, tremor, rigidity, and postural instability. Dr. Vijay Dhawan covers diagnostic and therapeutic applications of dopaminergic and metabolic imaging in PD and other movement disorders. Functional MRI has ushered in a new area in the imaging of cognitive brain activity and refines the management of patients with a variety of brain disorders while simultaneously revealing new insights into normal and abnormal cognitive function. Clinical applications have been on presurgical mapping of sensorimotor, language, and memory function as well as imaging of brain pathways mediating the emotions. Alzheimer's disease (AD) has been identified as a common form of dementia in the elderly, and its early, objective and quantitative indicators are important for clinical assessment and monitoring of therapeutic interventions. Dr. Frederik Giesel presents a recently developed post processing technique to segment and visulaize the ventricular system and measure ventricular volumes in patients with mild cognitive impairment and AD. Perfusion-weighted MRI is concerned with microscopic flow at the capillary level, and the contrast may be either endogenous or exogenous. Quantitative characterization of the full diffusion tensor is clinically avaliable, and diffusion anisotropy has been shown to vary widely within white matter. Diffusion tensor is a 3D data set in which each element inthe matrix has an associated magnitude and direction of diffusion. Dr. de Marco specifies the use of functional MRI data to explore putative networks of interconnected active areas and the various steps in the analysis of structural equation modeling (SEM) which uses theoretical and/or empirical hypotheses to estimate the effects (path coefficients) of an experimental task. Tracking gliomas dynamics on MRI has become important for therapeutic management. Dr. Hugues Duffau provides an extensive review of existing algorithms for the three computational tasks (image segmentation and registration as well as in silico growth modeling) involved in patient-specific tumor modeling. Interventional and surgical procedures in the abdomen or pelvis can result in urinary injury. Hemodynamically stable patients with microscopic hematuria are treated conservatively and probably do not need additional imaging. Multidetector CT (MDCT) is the method of choice for evaluating trauma patients with macroscopic hematuria and plays an important role in selecting treatment for the indivisual patient. A suspected vascular injury requires evaluation by CT angiography. Suspicion of injury to the renal collecting system or ureters needs delayed imaging during excretory phase. Dr. Maja Hrabak makes a pictorial review of iatrogenic urinary trauma diagnosed fast and accurately by MDCT cystography, urography and angiograpgy. Ultrasound contrast agents in conjunction with contrast specific imaging techniques are increasingly accepted in clinical use. Dr. Christian Gorg reports the use of sulfur hexafluoride based microbubble contrast medium (Sonovue) with contrastspecific continuous mode software (Acuson) for the diagnosis of various splenic pathology.