Reading an image

What does "reading" an image mean?

It is the trade name for the part of the examination that produces the report. The Royal College of Radiologists defines its specialists as "doctors trained to read and interpret medical images, using a wide range of imaging techniques including X-ray, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and molecular imaging". Reading is a trained act, not a glance: the same College notes that radiologists also "run patient clinics, take biopsy samples and prepare patients for surgery", and that the reading itself feeds the recorded evaluation the Ionising Radiation (Medical Exposure) Regulations 2017 require for every exposure.

The word is older than radiology and it travels. A fly-fishing journal published in Georgia, Riffle Notes, uses exactly the same verb for a river: reading the water means spotting the current seams, quiet pockets and depth changes that decide where a fish lies. The two readings share a structure: a surface full of information, most of it irrelevant, and a trained eye that knows which three features carry the answer. In both cases the skill is taught, practised and impossible to fake.

Who reads, and who acquires?

In the UK the two jobs are deliberately separated. The image is acquired by the radiographer, the professional who, as the NHS puts it on its MRI page of 11 September 2025, controls the scanner "from the neighbouring room" while keeping contact with the person inside. The title is protected: the Health and Care Professions Council states that "the professions we regulate have one or more designated titles that are protected by law", and "Radiographer", "Diagnostic radiographer" and "Therapeutic radiographer" are the titles it protects for this profession.

The image is read by the radiologist, a specialist doctor, or in some departments by another appropriately trained reporter. Sonography is the boundary case: the Society of Radiographers records that "the sonography workforce is currently unregulated and the title 'sonographer' is not a legally protected one", and that UK sonographers "come from many different professional backgrounds". An ultrasound examination may therefore be performed and described by one person, while a CT or MRI is acquired by one professional and reported by another.

How does the reading become the report?

Through a written duty. Schedule 2 of IR(ME)R 2017 requires the employer to keep a procedure "for the carrying out and recording of an evaluation for each exposure including, where appropriate, factors relevant to patient dose". The radiologist's report is the form that evaluation usually takes. The NHS then describes the journey back: for ultrasound, the conclusions go to the doctor who requested the examination, with results sometimes immediate and sometimes after "a few weeks"; for CT and MRI the quoted window is "usually takes between 1 and 2 weeks", with CT allowed "up to 4 weeks".

The reading is also audited, not just filed. Regulation 7 of the same regulations makes clinical audit an employer duty, defined in regulation 2 as "a systematic examination or review of medical radiological procedures which seeks to improve the quality and outcome of patient care". A report is therefore read twice in its life: once by the radiologist who writes it, and again, in aggregate, by the audit process that checks whether the department's practice meets its own standards.

Why the word "reading" survives the digital age

Because the task did not change when the picture did. Film was read on a light box; the digital image is read on a reporting workstation, but the act is identical in kind: compare what the picture shows against what anatomy should show, decide what the difference means for the question the referrer asked, and write it down. The Royal College of Radiologists frames the aptitudes plainly, describing radiologists as "problem-solvers with broad clinical knowledge and a keen eye for detail". The image supplies the evidence; the reading supplies the answer.