hjernavbildning

Hjernavnmbildning is a collective term for noninvasive methods that visualize the brain’s structure and function. It covers techniques used to examine anatomy, detect pathology, and study brain activity and metabolism. The field combines radiology, nuclear medicine, and neuroscience to aid diagnosis, treatment planning, and research.

Structural imaging focuses on the anatomy of the brain. Computed tomography (CT) uses X-rays to produce fast cross-sectional images and is often used in acute situations such as head trauma. Magnetic resonance imaging (MRI) uses strong magnetic fields and radio waves to generate high-resolution images of brain tissue, providing detailed views of gray and white matter, tumors, strokes, and structural abnormalities. Advanced MRI methods, such as diffusion tensor imaging (DTI), map the orientation of white matter tracts and support understanding of connectivity.

Functional imaging assesses brain activity or metabolism. Functional MRI (fMRI) measures blood flow changes associated with neural activity, enabling mapping of functional areas during tasks or at rest. Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) use radioactive tracers to visualize metabolic processes or receptor activity, aiding evaluation of neurodegenerative diseases, epilepsy, and cancer. These techniques can complement each other in clinical and research settings.

Applications include diagnosis and monitoring of stroke, tumors, multiple sclerosis, and dementia; localization of epileptic foci; pre-surgical planning; and investigation of cognitive and behavioral brain networks. Safety considerations vary by modality: CT and PET involve ionizing radiation; MRI requires screening for implants and devices and may pose claustrophobia risks. While powerful, imaging results must be interpreted alongside clinical information to avoid overdiagnosis or misinterpretation.