Amyloid-related imaging abnormalities (ARIA) are abnormal differences seen in

magnetic resonance imaging of the brain Magnetic resonance imaging of the brain uses magnetic resonance imaging (MRI) to produce high quality two-dimensional or three-dimensional images of the brain and brainstem as well as the cerebellum without the use of ionizing radiation (X-rays) or ...

in patients with

Alzheimer's disease Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ...

. ARIA is associated with amyloid-modifying therapies, particularly human

monoclonal antibodies A monoclonal antibody (mAb, more rarely called moAb) is an antibody produced from a cell Lineage made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell. Monoclonal antibodies ca ...

such as

aducanumab Aducanumab, sold under the brand name Aduhelm, is a medication designed to treat Alzheimer's disease (AD). It is a monoclonal antibody that targets aggregated forms (plaque) of amyloid beta (Aβ) found in the brains of people with Alzheimer's d ...

. There are two types of ARIA: ARIA-E and ARIA-H. The phenomenon was first seen in trials of

bapineuzumab Bapineuzumab (nicknamed "bapi") is a humanized monoclonal antibody that acts on the nervous system and may have potential therapeutic value for the treatment of Alzheimer's disease and possibly glaucoma. However, in 2012 it failed to produce sign ...

ARIA-E

ARIA-E refers to

cerebral edema Cerebral edema is excess accumulation of fluid (edema) in the intracellular or extracellular spaces of the brain. This typically causes impaired nerve function, increased pressure within the skull, and can eventually lead to direct compressio ...

, involving the breakdown of the tight endothelial junctions of the blood-brain barrier and subsequent accumulation of fluid. In a

double-blind In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expec ...

trial of the humanised monoclonal antibody

solanezumab Solanezumab (proposed INN, LY2062430) is a monoclonal antibody being investigated by Eli Lilly as a neuroprotector for patients with Alzheimer's disease. The drug originally attracted extensive media coverage proclaiming it a breakthrough, but ...

(n = 2042), sixteen patients (11 taking the drug, 5 taking a placebo), or 0.78% developed ARIA-E. A further 7 patients developed ARIA-E during an

open-label An open-label trial, or open trial, is a type of clinical trial in which information is not withheld from trial participants. In particular, both the researchers and participants know which treatment is being administered. This contrasts with a do ...

extension of the trial. The effect of ARIA-E depends on the severity and location of the edema. Symptoms may include

headache Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches. Headaches can occur as a result ...

, changes in mental state,

confusion In medicine, confusion is the quality or state of being bewildered or unclear. The term "acute mental confusion"

, vomiting, nausea, tremor and gait disturbances.

ARIA-H

ARIA-H refers to cerebral microhaemorrhages (mH), small

haemorrhages Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...

on the brain, often accompanied by

hemosiderosis Hemosiderosis is a form of iron overload disorder resulting in the accumulation of hemosiderin. Types include: * Transfusion hemosiderosis * Idiopathic pulmonary hemosiderosis * Transfusional diabetes Organs affected: * Hemosiderin depositi ...

. mH are usually seen as small, round and low intensity

lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classifi ...

s and are small

haemosiderin Hemosiderin image of a kidney viewed under a microscope. The brown areas represent hemosiderin Hemosiderin or haemosiderin is an iron-storage complex that is composed of partially digested ferritin and lysosomes. The breakdown of heme gives rise ...

deposits. Some studies define mH as being less than or equal to 10mm, while others define the cut-off as ≤ 5mm. The

prevalence In epidemiology, prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seatbelt use) at a specific time. It is derived by comparing the number o ...

of mH in healthy elderly people is approximately 6%, but this value increases to between 50% and 80% in elderly people with

cerebrovascular disease Cerebrovascular disease includes a variety of medical conditions that affect the blood vessels of the brain and the cerebral circulation. Arteries supplying oxygen and nutrients to the brain are often damaged or deformed in these disorders. The ...

ARIA MRI Classification Criteria

References

External links

{{Medical resources , ICD10 = , ICD9 = , ICDO = , OMIM = , DiseasesDB = , MedlinePlus = , eMedicineSubj = , eMedicineTopic = , MeshID = Alzheimer's disease Neuroimaging Magnetic resonance imaging