Computerized Tomography (CT) Scan |
CT scans utilize an integrative
approach with motorized X-ray sources and advanced mathematical methods
to construct two-dimensional (2-D) cross-sectional images of the
patient. Using a computer, the 2-D images can then be coupled to create
advanced three-dimensional images of biological systems. |
CT scans can
identify regions of brain shrinkage and amyloid plaques. Additionally,
CT scans are utilized to confirm that other brain abnormalities such as,
tumors, subdural hematomas, and strokes are not the source of AD
symptoms |
Magnetic Resonance Imaging (MRI) |
MRIs implement a highly potent
magnetic field to stimulate protons in the body to orient towards the
applied magnetic field. Once the radiofrequency field initially applied
is removed, MRI detectors measure the energy released by the protons to
reorient with the magnetic field. Biological tissue varies across
systems, with each having their own unique magnetic properties. |
MRIs
can show regions afflicted with brain atrophy and detailed images of
blood vessels in the brain. Furthermore, MRIs are employed to confirm
that bleeding in the brain and fluid build-up are not contributing to
the appearance of AD symptoms. |
Positron Emission Tomography (PET) Scan
|
PET Scans carry out their function by utilizing an injected radioactive
isotope that emits positrons. The emitted positrons then collide with
electrons present in biological tissue to form two photons. These
photons are detected by scintillation crystals integrated within the PET
scanner. The scintillation crystals absorb the photons and then convert
the light energy derived from the photons into applicable electrical
signals.
|
Amyloid PET scans measure the pathological accumulation of beta-amyloid
proteins.
Tau PET scans identify the abnormal accumulation of tau proteins.
Fluorodeoxyglucose (FDG) PET scans quantify energy utilization in the
brain. Widespread studies have indicated that dementia patients often
show decreased glucose consumption in certain regions of the
brain.
|
Lumbar Punctures |
Lumbar punctures are performed by inserting a hollow
needle into the subarachnoid space of the spinal column to collect
samples of CSF. |
Lumbar punctures can identify abnormal levels of
beta-amyloid 42, tau, and phospho-tau in CSF. All of these proteins are
critical AD biomarkers. |