Describing a Finding
- Describing a finding means turning what you see into words precise enough that someone who can't see your screen knows exactly what you mean.
- A good description answers a fixed set of questions: where it is, how big, what it looks like, and how its edges behave.
- Describe first, diagnose second. Naming the disease too early makes you stop looking and stop describing.
- Use the same words everyone else uses. Inventing your own vocabulary is the radiology equivalent of giving directions using landmarks only you can see.
Imagine calling a friend to describe a dog you saw. "It was, like, a dog. Brownish. Medium." Useless. Now imagine: "A knee-high short-haired dog, tan with a black muzzle, pointed ears, standing at the corner of 5th and Main." Suddenly your friend can practically pick it out of a lineup. That second version is what radiologists are doing all day, except the dog is a shadow on a scan and the friend is a surgeon deciding whether to operate.
Describing a finding is the unglamorous skill that everything else sits on top of. You can't reach the right diagnosis if you can't first say, out loud and precisely, what you're looking at.
Why bother describing it at all? Just say what it is
Tempting, but backwards. The moment you blurt out a diagnosis, your brain quietly closes the file and stops examining the evidence. I've talked myself into "obvious pneumonia" and then noticed, a beat too late, the rib fracture sitting right next to it that I'd stopped looking for.
Describing forces you to slow down and actually account for what's on the image. It's also how you communicate when you're not sure — and you're often not sure. A precise description of an uncertain thing is far more useful to the next doctor than a confident guess.
A finding is what you observe. A diagnosis is what you think it means. Keep them in separate sentences. "There is a 2 cm rounded opacity in the right upper lobe" is a finding. "Likely a granuloma" is the interpretation. The first one is hard to argue with; the second one is a discussion.
The checklist: the questions every finding has to answer
Whether it's a lung shadow, a liver lump, or a bright spot in the brain, you can describe almost anything by marching through the same short list. Think of it as the standard intake form a finding has to fill out before it's allowed to leave.
| Question | What you're pinning down | Example phrasing |
|---|---|---|
| Where? | Precise location — organ, lobe, segment, side | "in the medial right lower lobe" |
| How many / how big? | Single vs multiple; measured size | "a solitary 14 mm nodule" |
| What density / signal? | How bright or dark, vs nearby tissue | "low density relative to liver" |
| What shape & margin? | Round vs irregular; sharp vs fuzzy edge | "round with smooth, well-defined margins" |
| What's it doing to neighbors? | Pushing, invading, surrounding fluid | "displacing the adjacent vessel without invading it" |
You won't always have an answer to every line, and that's fine — but running the list means you never accidentally forget to mention that the "small nodule" was actually one of fifteen.
Location: be boringly specific
"Left lung" is a county. The surgeon wants a street address. Use the named anatomy — lobes, segments, vascular territories — because those are the words that survive the trip from your screen to someone else's brain intact. This is also where a disciplined search pattern pays off: you can't localize against a map you don't have.
Density and signal: bright, dark, or somewhere in between
You can't describe how something looks without a reference point. On a radiograph or CT, that anchor is the four basic radiographic densities — is the thing as dark as air, as gray as soft tissue, as white as bone? On MRI we instead say "high signal" or "low signal" on a particular sequence, because brightness on MRI depends entirely on which sequence you're looking at.
The trick is to always describe relative to a neighbor: "denser than the surrounding lung," "darker than liver." Absolute words like "white" mean different things depending on how the image is displayed (window settings can make the same pixel look snow-white or charcoal). Comparison is honest; absolutes lie.
When you're unsure, compare the finding to a structure of known density in the same image — muscle, fat, fluid, vessel. "Similar density to the adjacent muscle" tells the reader far more than "kind of gray," and it's a comparison nobody can dispute.
Margins: the edge tells a story
How a finding meets its surroundings is often the single most informative feature, so don't rush past it. A smooth, sharply drawn edge tends to suggest something slow and well-behaved — picture a marble dropped on a table, holding its tidy outline. A fuzzy, spiculated, or ill-defined edge — more like a drop of ink bleeding into a paper towel — tends to suggest something more aggressive or actively spreading. These are tendencies, not promises, but the margin is so useful that leaving it out of a description is like describing a coastline without saying whether it's a clean cliff or a marsh.
Don't let the diagnosis you're hoping for sand the edges of what you describe. If a mass has an irregular margin, say "irregular" even if you'd love it to be benign. The description is a record of what's actually there; bending it to fit your favorite diagnosis is how misses happen.
Putting it together (and a note on numbers)
Strung together, the checklist becomes one clean sentence: "A solitary 14 mm rounded nodule with smooth margins in the right lower lobe, of soft-tissue density, not invading the adjacent pleura." Anyone reading that can picture it without ever seeing your screen — which is the entire point.
A few habits keep descriptions trustworthy. Measure, don't eyeball, when size matters — "14 mm" travels and gets compared to next year's scan; "smallish" does not. Note laterality explicitly, because left/right errors are dangerously easy. And when something is genuinely borderline, say so rather than forcing a crisp label onto a fuzzy reality.
This same describe-then-interpret discipline shows up everywhere in radiology — it's exactly how you'd describe a fracture, too — and it's the raw material that eventually becomes the formal radiology report.
If you remember nothing else: describe what you see before you decide what it means. Pin down where it is, how big, what it looks like, and how its edges behave — in words specific enough that a colleague who can't see the image could nod and say, "Yep, I know exactly what you're looking at."