A 24-year-old woman, possibly pregnant, has right iliac fossa pain. Which imaging should be considered FIRST? A. CT abdomen B. Ultrasound C. Plain abdominal X-ray D. MRI ANSWER: B — ultrasound. WHY: it uses NO ionising radiation, is portable and repeatable, and can answer the question in many cases — so it is the first choice in PREGNANCY and in CHILDREN wherever it will do. A: CT carries a substantially higher radiation dose. It may still be necessary, but not as the first step here. C: a plain abdominal film rarely answers this question and still uses radiation. D: MRI avoids radiation but is slow, costly and less available. ALWAYS: ask about pregnancy BEFORE the scan and record that you asked.

What single question determines whether an imaging request is justified? ANSWER: WILL THE RESULT CHANGE MANAGEMENT? If a normal result and an abnormal result would both lead to the same next step, the scan is not justified — however reassuring it would feel to order, and however much it is expected. WHY THIS MATTERS: every request using ionising radiation carries a small increase in lifetime cancer risk. That is usually worth accepting, but only in exchange for information that alters what you do. TWO GROUPS NEEDING PARTICULAR CARE: CHILDREN — more radiosensitive, and longer for harm to develop WOMEN who might be pregnant THE REVERSE ERROR IS ALSO REAL: withholding a scan that would identify a life-threatening problem in a pregnant woman harms both her and the fetus. Ask the question; do not refuse imaging in pregnancy.

Why is a systematic approach to reading a chest film important? ANSWER: because finding ONE abnormality makes the eye STOP LOOKING — and the second one is missed. This is the commonest interpretation error, and it is not a failure of knowledge but of search. A WORKABLE ORDER: 1. The film itself — right patient, right date, adequate rotation, inspiration and penetration 2. AIRWAY — trachea central, pushed or pulled? 3. BREATHING — lung fields, side to side 4. CIRCULATION — heart size and mediastinum 5. DIAPHRAGM — both domes and the space beneath 6. EVERYTHING ELSE CHECK THE EDGES LAST, because that is where findings hide: apices, costophrenic angles, UNDER THE DIAPHRAGM (free air), behind the heart, and the BONES.

A patient has a convincing clinical picture of appendicitis but the ultrasound is reported as normal. What now? ANSWER: a normal image does NOT exclude the disease. Act on the clinical picture. 1. Ultrasound is operator-dependent and the appendix is not always visualised. 2. Early disease may not yet show changes. 3. A "normal" report may mean "the appendix was not seen", which is not the same as "the appendix is normal". WHAT TO DO: continue to manage as suspected appendicitis — observe, re-examine, discuss with the surgical team, and consider repeating or escalating the imaging. THE GENERAL PRINCIPLE: TREAT THE PATIENT, NOT THE REPORT. A convincing clinical picture outweighs a reassuring film. The opposite habit is how a deteriorating patient gets watched instead of treated.

Why is an early CT head often normal in ischaemic stroke, and what is the scan actually for? ANSWER: ischaemic changes take time to become visible on CT. The scan is done primarily to EXCLUDE HAEMORRHAGE. 1. In the first hours, an infarct commonly shows little or nothing. 2. A normal CT therefore does not exclude a stroke. 3. But BLEEDING is visible immediately. WHY THAT DISTINCTION IS THE WHOLE POINT: treatment for ischaemic stroke would be catastrophic if given to someone bleeding into the brain. The scan's job is to answer "is this a bleed?" — not "is this a stroke?" This is a good example of knowing WHAT QUESTION a test is answering rather than treating it as a general look.

Rewrite this request so it produces a useful report: "Abdomen ? cause" ANSWER: give the findings, the duration and the SPECIFIC QUESTION. BETTER: "Right iliac fossa pain 12 hours, localised tenderness and guarding, raised inflammatory markers. Query appendicitis. Query free fluid." WHY IT MATTERS: 1. The radiologist knows WHERE to concentrate. 2. Telling them WHAT YOU FEAR changes where they look — someone told you are worried about perforation looks specifically for free air. 3. Told nothing, they report in general terms, and the subtle finding you needed may not be commented on. BROADER POINT: the radiologist is a CONSULTANT COLLEAGUE, not a service counter. Given the clinical problem they will often suggest a better test than the one requested — sometimes that no imaging is needed at all.

A CT for abdominal pain reports a small incidental lesion unrelated to the symptoms. What is the risk of pursuing it? ANSWER: investigation of INCIDENTAL FINDINGS carries real harm. 1. Incidental findings are common, especially on CT, and most are harmless. 2. Pursuing them generates further imaging and further radiation. 3. It generates ANXIETY in a patient who was well. 4. It generates cost. 5. It can lead to biopsy or surgery — with genuine procedural risk — for something that was never causing symptoms. SO: an abnormal image is NOT automatically the answer to the clinical question. Decide what you think BEFORE reading the report, and notice when the report and the patient disagree. Incidental findings still require appropriate follow-up where guidance exists — the point is that pursuit should be considered, not automatic.