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Intracardiac echocardiography

Intracardiac echocardiography (ICE) is catheter-based ultrasound imaging from inside the heart, used instead of TEE or fluoroscopy to guide transseptal puncture, AF ablation, ASD/PFO closure, and left atrial appendage occlusion.

Intracardiac thrombosis

Intracardiac thrombosis, also called intracardiac thrombus, is a blood clot forming inside a heart chamber, most often the left ventricle or left atrial appendage in atrial fibrillation or myocardial infarction; it is the most common cardiac mass and is detected mainly by echocardiography, CT, and CMR.

Intracavernosal injection

Intracavernosal injection (ICI) is a urological procedure in which a vasoactive drug is injected into the corpora cavernosa of the penis, a second-line erectile dysfunction treatment after PDE5 inhibitors.

Intracavernous injection

Intracavernous injection is a procedure that injects vasoactive drugs such as alprostadil directly into the corpora cavernosa of the penis to produce an erection for treating erectile dysfunction.

Intracellular chloride channel

Intracellular chloride channel: chloride-conducting channels of organelle membranes, including intracellular ClCs, bestrophins, CFTR, GPHR, and the six-member CLIC (p64) family, whose channel status is disputed.

Intracellular cobalamin processing defects (cbl groups)

Intracellular cobalamin processing defects are inherited disorders in which vitamin B12 cannot be converted into its active cofactors, classified into complementation groups cblA through cblJ.

Intracellular cytokine staining

Intracellular cytokine staining is a flow cytometry method that fixes and permeabilizes stimulated cells so fluorescent antibodies can measure cytokine production one cell at a time, resolving polyfunctionality.

Intracellular staining

Intracellular staining is a cytometry and microscopy technique in which cells are fixed and permeabilized so fluorescent antibodies can bind intracellular targets such as cytokines and transcription factors.

Intracerebral administration

Intracerebral administration is a drug delivery route in which a therapeutic agent is injected or infused directly into brain tissue, bypassing the blood–brain barrier, mainly through convection-enhanced delivery.

Intracerebral haemorrhage

Intracerebral haemorrhage (ICH), also called hemorrhagic stroke, is non-traumatic bleeding into brain parenchyma; the deadliest stroke type, over 10% of strokes, >40% mortality, treated with blood pressure control, hemostasis, and rehabilitation.

Intracerebral hemorrhage

Intracerebral hemorrhage (ICH), nontraumatic brain bleeding, second deadliest stroke type; ~10-20% of strokes, one-third die within a month; treated with early blood pressure control, care bundles, and minimally invasive clot evacuation (MISTIE III, ENRICH).

Intracerebroventricular injection

Intracerebroventricular (ICV) injection delivers substances such as drugs, antisense oligonucleotides, and gene therapy vectors into the brain's fluid-filled ventricles, bypassing the blood–brain barrier; it is used in animal research and approved therapies like cerliponase alfa.

Intraclass correlation

The intraclass correlation (ICC), also called the intracluster correlation, measures how strongly measurements on units in the same group resemble each other, as the share of variance between classes.

Oct 15, 2026

Intracluster light

Intracluster light (ICL) is faint, diffuse light from stars bound to a galaxy cluster's halo rather than to any individual galaxy, first proposed by Fritz Zwicky in 1937.

Intracluster medium

The intracluster medium (ICM) is the hot, tenuous plasma filling the space between galaxies in a cluster, hotter than 10 million degrees and shining in X rays.

Intracoastal Waterway

The Intracoastal Waterway (ICW) is a system of protected inshore channels along the Atlantic and Gulf coasts of the United States, from New Jersey to Texas.

Intracolonic administration

Intracolonic administration is a route of drug delivery in which the dose is placed directly into the colon, typically through an enema or a colonoscopically guided catheter.

Intracranial aneurysm

Intracranial (cerebral, brain) aneurysm: localized dilation of a brain artery; rupture causes subarachnoid hemorrhage. Treated by microsurgical clipping (first done by Dandy, 1937) or endovascular coiling (GDC, 1991).

Intracranial electroencephalography

Intracranial electroencephalography (iEEG) records brain electrical activity from electrodes inside the skull, either on the cortical surface (ECoG) or within the brain (SEEG), to localize seizure onset before surgery for drug-resistant epilepsy.

Intracranial granuloma

Intracranial granuloma (ICD-11 1D04.1) is a focal intracranial mass of macrophages and giant cells caused by infection (tuberculoma, fungal, parasitic), sarcoidosis, or foreign material; diagnosed by CT/MRI and biopsy.

Intracranial hemorrhage

Intracranial hemorrhage, also called intracerebral or subarachnoid hemorrhage, is bleeding inside the skull. It causes 10-20% of strokes, has 30-40% early mortality, and is treated per the 2022 AHA/ASA guideline.

Intracranial hypotension

Intracranial hypotension, also called spontaneous intracranial hypotension (SIH) or CSF hypovolemia, is low CSF volume from a spinal leak causing orthostatic headache; incidence 3.7/100,000, treated with epidural blood patch or surgery.

Intracranial pressure

Intracranial pressure (ICP), also called intracranial hypertension when elevated, is the pressure inside the rigid skull from brain, blood, and CSF. Normal 7–15 mm Hg; above 20–25 mm Hg pathological, treated with osmotherapy, drainage, or craniectomy.

Intracranial recording

Intracranial recording, also called intracranial EEG or iEEG, measures electrical activity directly from electrodes inside the skull or brain, chiefly to localize seizure onset in drug-resistant epilepsy.

Intracranial space-occupying lesion

Intracranial space-occupying lesion (ICD-11 MB71.0, ICD-10-CM R90.0), also called intracranial mass lesion: any discrete intracranial lesion causing mass effect, mainly tumor, hemorrhage, abscess, or infarction, evaluated chiefly by contrast-enhanced MRI.

Intracranial vascular malformation

Intracranial vascular malformation (ICD-11 8B22.4): abnormal brain blood vessels including AVMs, dural fistulas, cavernous malformations, venous anomalies, and telangiectasias, differing in hemorrhage risk and treatment.

Intracytoplasmic sperm injection

Intracytoplasmic sperm injection (ICSI): IVF micromanipulation technique injecting one spermatozoon into an oocyte's cytoplasm; first human success by Palermo et al. in 1992; standard for severe male factor infertility, used in ~70% of cycles, but no live-birth benefit over conventional IVF without male factor.

Intradermal injection

Intradermal injection delivers a small volume of drug or vaccine into the dermis, used for tuberculin and allergy skin tests and for dose-sparing vaccination against rabies, influenza, and mpox.

Intradermal test

An intradermal test is a diagnostic skin test that injects allergen or antigen into the dermis, detecting immediate IgE-mediated or delayed hypersensitivity, used in allergy workup and tuberculosis screening.