Aortic dissection

What it means

The aorta is a large, high-pressure artery with a wall made of several layers. A dissection begins when a tear opens in the innermost layer, and blood surges through it and forces its way between the layers, creating a second, false channel running alongside the real one. This splits the wall lengthwise over a variable distance — sometimes a short segment, sometimes the whole length of the aorta from the chest into the abdomen. The weakened, two-channel wall is at risk of rupturing or of cutting off blood supply to organs branching off the aorta.

Why it appears on a CT or MRI report

CT with contrast dye is the fastest and most common way to diagnose it, especially in the emergency setting, and shows a thin line (the intimal flap) separating a "true" and "false" channel within the aortic wall. Reports classify it by location — Stanford type A involves the first part of the aorta as it leaves the heart and is considered surgical; type B is limited to the aorta further along and is often, though not always, managed with medication first. The report will describe the extent, whether major branch arteries are involved, and whether there are complications like a contained leak, poor blood flow to an organ, or a widening of the aorta at the tear.

What it usually means

Even when a report uses calm technical language — "stable," "chronic," "without active extravasation" — a dissection is always a serious diagnosis that requires care from a specialist team, because the false channel remains a point of weakness in the aorta for as long as it exists. Acute dissections (found within about two weeks of onset) carry the highest immediate risk and are managed urgently: type A almost always needs emergency surgery, while type B is frequently treated first with aggressive blood pressure control, and sometimes a stent placed inside the vessel if complications appear. Dissections found weeks, months, or years after the original event are called chronic; the wall has had time to stabilize, but it needs ongoing monitoring for gradual widening, since a chronic dissection can still eventually require repair.

When to follow up

If you are reading this because you or someone with you has chest, back, or abdominal pain described as sudden, severe, tearing, or ripping — especially pain that moves from the chest into the back — seek emergency care immediately or call emergency services; do not wait for a scheduled appointment. If a dissection has already been diagnosed and you've been discharged with a treatment plan, keep every follow-up imaging appointment, take blood pressure medication exactly as prescribed, and contact your care team promptly for new or worsening pain, fainting, weakness on one side, or leg pain and coolness.

A plain-language way to picture it

Think of the aorta as a length of layered garden hose, with an inner tube and an outer sleeve bonded together. A dissection is a small nick in the inner tube that lets water force its way between the layers, ballooning a second channel along the hose's length and pushing the inner tube out of shape. The hose can keep carrying some water through the true channel, but the wall between the two channels is now thin and under strain — which is why the situation is treated as urgent rather than watched from a distance.