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Subependymal giant cell astrocytoma (SEGA, SGCA, or SGCT) is a low-grade astrocytic brain tumor (astrocytoma) that arises within the ventricles of the brain. [1] It is most commonly associated with tuberous sclerosis complex (TSC). Although it is a low-grade tumor, its location can potentially obstruct the ventricles and lead to hydrocephalus.
Arterial spin labeling (ASL), also known as arterial spin tagging, is a magnetic resonance imaging technique used to quantify cerebral blood perfusion by labelling blood water as it flows throughout the brain. ASL specifically refers to magnetic labeling of arterial blood below or in the imaging slab, without the need of gadolinium contrast. [1]
Grading of the tumor sample is a method of classification that helps the doctor to determine the severity of the astrocytoma and to decide on the best treatment options. The neuropathologist grades the tumor by looking for atypical cells, the growth of new blood vessels, and for indicators of cell division called mitotic figures. [citation needed]
As a free solubilized aqueous ion, gadolinium(III) is highly toxic, but the chelated compounds are generally regarded as safe for individuals without kidney disease. Free Gd 3+ has a median lethal dose of 0.34 mmol/kg (IV, mouse) [27] or 100–200 mg/kg, but the LD50 is increased by a factor of 31 times [28] when Gd 3+ is chelated. [29]
Structural magnetic resonance imaging (structural MRI) of a head, from top to base of the skull. The first chapter of the history of neuroimaging traces back to the Italian neuroscientist Angelo Mosso who invented the 'human circulation balance', which could non-invasively measure the redistribution of blood during emotional and intellectual activity.
The contrast agents used for DCE-MRI are often gadolinium based. Interaction with the gadolinium (Gd) contrast agent (commonly a gadolinium ion chelate) causes the relaxation time of water protons to decrease, and therefore images acquired after gadolinium injection display higher signal in T1-weighted images indicating the present of the agent.
Thalamic gliomas are most often discovered on magnetic resonance imaging following symptoms, with the most common presenting symptom being motor deficit. [2] While a definitive diagnosis of the neoplasm cannot be made without a biopsy of the tumor, biopsies have historically been avoided due to the extreme sensitivity of the region.
SPECT can be used to complement any gamma imaging study, where a true 3D representation can be helpful, such as tumor imaging, infection imaging, thyroid imaging or bone scintigraphy. Because SPECT permits accurate localisation in 3D space, it can be used to provide information about localised function in internal organs, such as functional ...