A Referring Clinician's Guide
- A radiology request is a question, not a vending-machine order — the better the question, the better the answer you get back.
- Give us the clinical story, not just a body part. "65M, sudden tearing chest pain, hypertensive" tells us far more than "chest pain, please CT."
- The right test depends on the question, the patient, and the trade-offs (radiation, contrast, time, availability) — there isn't one "best scan."
- When you're stuck, call the radiologist. We genuinely like the protocol question more than the angry one later.
Think of ordering imaging like sending a friend to the grocery store. If you text "get food," you will get something, but probably not dinner. If you text "get the ingredients for spaghetti — pasta, tomatoes, garlic," you get exactly what you needed. A radiology request works the same way: we can only answer the question you actually ask. This page is a field guide to asking well.
We answer questions, not anatomy
The single most common ordering mistake isn't picking the wrong scan — it's forgetting to say why. A request that reads "abdomen pain, CT" leaves the radiologist guessing whether you're worried about appendicitis, a kidney stone, or a leaking aneurysm. Those are three different protocols, three different contrast decisions, and three different sets of things we'll scrutinize.
So write the request like you're handing off to a colleague at 3 a.m.: a sentence of story, the specific worry, and any landmines (allergies, kidney function, pregnancy, devices). For more on matching the question to the modality, see Which Test, When.
A useful template: Who (age, sex, relevant history) + What (symptom, duration, exam finding) + Why (the diagnosis you're trying to confirm or exclude). "72F on warfarin, fell, now confused — exclude intracranial bleed." That request basically protocols itself.
A starting cheat-sheet, not a recipe book
Here's a rough map of common questions to a sensible first test. Treat it as a conversation-starter — your local protocols and the patient in front of you always win, and formal appropriateness guidance exists for the gray zones.
| Clinical question | Reasonable first test | Note |
|---|---|---|
| Suspected pulmonary embolism | CT pulmonary angiogram | Needs IV contrast; check kidney function. |
| Acute stroke symptoms | Non-contrast head CT first | Fast, rules out bleed before treatment. |
| Renal colic / flank pain | Non-contrast CT (CT KUB) | Stones don't need contrast to be seen. |
| First-trimester pelvic pain/bleeding | Pelvic ultrasound | No radiation; great for early pregnancy. |
| Suspected appendicitis (adult) | CT abdomen/pelvis with contrast | Ultrasound often first in kids/pregnancy. |
Notice the contrast decisions aren't random. Whether to give iodine depends on what you're hunting; the deeper logic lives in Contrast vs Non-Contrast.
The fine print on contrast and radiation
Two trade-offs trip people up most. The first is contrast. Iodinated contrast makes vessels and many lesions pop, but it has costs — so we'll often ask about kidney function and prior reactions. A documented contrast reaction history changes the plan, not necessarily cancels it. Tell us early.
The second is radiation. CT is a workhorse, but it isn't free; the dose is real even if the individual risk is small (the long view is in Radiation Biology & Risk). This matters most in two groups — children and pregnant patients — where we lean toward ultrasound and MRI when they can answer the question. See Pregnancy & Pediatric Dose.
"Just scan everything" is not a plan. A pan-CT on a young patient with a clear, localized problem hands them radiation and a high chance of an incidental finding — a harmless-looking spot that now demands follow-up, anxiety, and sometimes a biopsy of something that was never going to bother them.
Stat means stat (and other workflow truths)
Marking everything "STAT" is the imaging equivalent of crying wolf — if it's all urgent, nothing is. Reserve it for results that change management in the next hour, and the genuinely urgent studies will move faster.
If a finding is truly time-critical, the radiologist will call you directly. That closed-loop phone call is a safety net, not an insult — it's how critical results get communicated reliably.
A few small habits that make everyone's day better: flag implanted devices before an MRI (a pacemaker is not a "we'll sort it out at the scanner" problem), include the relevant prior history so we can compare, and tell us about clinical instability so the study gets the right monitoring.
How to read what comes back
The report is the answer to your question, so it helps to know how it's built — the impression up top is the punchline, and the body is the supporting evidence. If a report ever leaves your actual question unanswered, that's worth a call; sometimes the request didn't make the question clear, and sometimes we genuinely missed your point. The anatomy of a good report is covered in Writing a Great Radiology Report.
The one thing to remember
Imaging isn't a box to tick — it's a consult with a machine in the middle and a radiologist on the other end. Ask a sharp clinical question, share the landmines, and pick up the phone when you're unsure. Do that, and the scan stops being a guessing game and starts being the answer you actually needed.