Radiology report: what each part means and how to read it after the fact

A radiology report is the written result of an imaging study. A technologist acquires the images; a radiologist, or another authorized practitioner, reads them and dictates or types the report. The report goes to the clinician who ordered the study, and it becomes part of the medical record.

The images and the report are separate records. The images are what the scanner captured. The report is 1 physician's interpretation of them, written at 1 point in time with the history and prior studies available at that moment. When a case turns on whether something was missed, experts look at the images. Everyone else, including the treating doctors at the time, usually worked from the report.

That is why the report deserves close reading. What it says, where it says it (findings or impression), whether it recommends follow-up, when it was finalized and who it was sent to are all facts that can be established from the record without reading a single image.

Terms you will meet

Indication

The clinical question or reason for the exam, usually copied from the order.

Technique

How the study was done: modality, body part, protocol, contrast.

Comparison

Prior studies the radiologist compared against, or a statement that none were available.

Findings

The body of the report: what was seen, organ by organ or region by region.

Impression

The conclusion. Many clinicians read only this section.

Preliminary report

An early read, often overnight by a resident or teleradiologist, that directs immediate care before the final report. Also called a wet read.

Addendum

A later addition to a signed report, dated separately. The original text should remain.

Incidental finding

Something unrelated to the clinical question, such as a lung nodule on a scan ordered for a clot.

The mock report below is a CT scan ordered in an emergency department to rule out a blood clot in the lungs. The layout is invented. The 9 marked parts follow the structure the American College of Radiology suggests for diagnostic imaging reports.

What a radiology report can and cannot tell you

Many studies produce more than 1 report. Overnight and in emergencies, a resident, a teleradiology service or an on-call radiologist gives a preliminary read so care can proceed. The final report comes later, sometimes hours later. The ACR practice parameter says a preliminary report "very likely will contain limited or incomplete information" and should be kept, labeled as preliminary, because clinical decisions may have been based on it.

The ACR expects a significant difference between the preliminary and final reads to be reported to the treating clinician in a way that "reasonably ensures receipt," and the communication to be documented in the final report. In a well-run department such changes are uncommon: 1 academic center found major discrepancies in 0.89% of 45,608 resident preliminary reads over a year. Uncommon is not never, and the file should show what happened when there was one.

Urgent and unexpected findings

The ACR describes 3 situations that call for communication beyond the routine report: findings needing immediate intervention (a collapsed lung, a misplaced tube), findings that differ from an earlier read of the same study, and significant unexpected findings that could worsen if not acted on. For these, the interpreting physician should call or otherwise reach the treating clinician, and document the date, time, method and person reached.

"Interpreting physicians should document all nonroutine communications."

Federal rules cover signing and keeping radiology reports in hospitals, and set detailed content and delivery rules for mammography. The ACR practice parameter is a professional standard, not a regulation, but it is widely cited as the benchmark for what a report should contain and how findings should be communicated.

CMS guidance to surveyors adds that radiology records must include, at a minimum, the orders for the services, copies of reports and printouts, and the images. Radiology records are patient medical records, so the general medical record rules apply to them too. The mammography rules also require the report to address every clinical question the referring provider raised, "even if the assessment is negative or benign."

The ACR also says the ordering clinician shares responsibility for obtaining imaging results. In a missed follow-up case, both sides of that handoff are in the record: the report and its distribution on 1 side, the clinician's result inbox and notes on the other.

Radiology errors are a studied subject with a large literature. A 2015 review in RadioGraphics notes that the overall rate of radiologists' errors has not changed since it was first estimated in the 1960s, and divides them into perceptual errors, where the abnormality is not seen, and cognitive errors, where it is seen but misjudged.

Kim and Mansfield reviewed 656 imaging exams with delayed diagnoses, collected at 1 center from 2002 to 2010, and classified 1,269 errors:

The last number is the one reviewers should remember. A miss tends to repeat, partly because later readers compare against the earlier report. So a delayed diagnosis case often involves a series of reports, each of which needs its own review.

Reporting a finding does not guarantee it is acted on. Blagev and colleagues reviewed 1,000 emergency department CT scans for blood clots. 9.9% had incidental lung nodules that needed follow-up under published guidelines. Only 29% (28 of 96) were followed up. When the nodule appeared only in the findings section, the follow-up rate was 0 of 12. Even when the report explicitly recommended follow-up, it was 29% (19 of 65).

What each flag means

1. A preliminary read that answered only the question asked. "No PE" was the right answer to the order. Whether the nodule should have been in the preliminary read is a question for a radiology expert.
2. Discharge before the final report. The ED note calls the CT negative nearly 7 hours before the final report was signed. Any later review of the final report by the ED team would be in the ED's result inbox logs.
3. A finding without an impression or recommendation. The nodule is in the findings only. Whether a follow-up recommendation was expected is for the expert; the study data say findings-only nodules were rarely followed up.
4. A distribution list without the primary care doctor. The report went to the ordering physician. The PCP note repeats "CT neg."
5. A later scan without comparison. The 2026 report says no prior studies were available, though the 2025 CT is in the same system. Growth over 14 months is what a comparison would have shown.
6. A 13-month gap. No imaging, no mention of the nodule in any note.

The same case on 1 timeline

The method works for a single X-ray or a series of scans over years. The goal is a list of what each report said, where, when and to whom, and what the clinicians did next.

1. List every study. Every imaging exam in the file, with date, modality and ordering provider.
2. Collect every version. Preliminary, final, addenda and outside reads for each study.
3. Read the whole report. Findings, limitations, impression and recommendations, in that order.
4. Mark the gaps between sections. Findings not carried into the impression, and recommendations that are missing or vague.
5. Compare versions. Differences between preliminary and final, and whether the change was communicated and documented.
6. Check comparisons. Whether each report compared against the prior studies that existed.
7. Follow the report. Distribution list, result acknowledgment, and the next clinician note that mentions it.
8. Follow the recommendation. Whether recommended imaging or tests were ordered, done and read.

Does this radiology report need a closer look?

RADIOLOGY REPORT CHECKLIST
Study: [MODALITY, BODY PART]   Date/time: [ ]
Facility: [ ]   Ordering provider: [ ]
Report version: [preliminary / final / addendum / corrected]

[ ] Indication stated and addressed in the impression
[ ] Technique, contrast and dose stated
[ ] Comparison studies named, or "none" (check if priors exist)
[ ] Findings: every abnormal finding listed
[ ] Limitations stated if the study was compromised
[ ] Impression answers the clinical question
[ ] Every significant finding carried into the impression
[ ] Follow-up recommendation stated where appropriate
[ ] Urgent or unexpected finding: call documented
    (date, time, method, person reached)
[ ] Dictated / preliminary / final times and signer
[ ] Distribution: who received the report
[ ] Mammography: assessment category, density,
    lay letter date, provider report date

IMAGING REVIEW LOG
Patient: [ID]    Period: [DATES]

Date/time | Study | Version (prelim / final / addendum)
  | Findings (page) | Impression (page)
  | Recommendation | Sent to | Next action found (page)
  | Question

Example:
03/11/2025 08:10 | CT angiogram chest | Final
  | 8 mm solid RUL nodule (p. 9) | No PE (p. 10)
  | None | ED attending | PCP note "CT neg" (p. 22)
  | Findings-only nodule, PCP not on distribution

Before you rely on a radiology report

• Every version is in handPreliminary, final, addenda, outside reads.
• The images are requestedFor any read an expert will need to assess.
• Signature times are knownFor each version, with the signer.
• The distribution record is in handWho received the report, and when.
• Prior studies are listedTo check each comparison statement.
• Clinician notes after each study are in handTo find what was done with the result.

0 of 6 checked.

A radiology report often leads to a biopsy; the pathology report guide covers what comes next. For hospital stays, the discharge summary guide covers results still pending when the patient leaves, and the EHR audit trail guide covers how to prove who opened a result and when.

A delayed diagnosis file can hold dozens of imaging reports over several years, each with its own versions, next to thousands of pages of clinical notes. Chapter 7's method asks for every finding, every recommendation and every follow-up action to be lined up by date. Doing that by hand is where findings-only items and missing comparisons get missed a second time.

AI medical record review can read every report in the file, pull each finding, impression and recommendation onto an AI medical chronology with a page-level citation, and put the clinician notes that follow beside them. A nodule reported in March and never mentioned again shows up as a gap you can check in seconds.

2 limits matter here. The software reads the report text, not the images; whether a finding was visible is a question for a radiologist looking at the scans. And a large language model (LLM) can hallucinate or drop a finding, which is why every line needs its page and a human in the loop checks it.

Medrecords AI works this way on the files you upload. It builds a cited medical chronology across imaging, pathology and clinical notes, each entry linked to its page. You can ask "every imaging finding with a follow-up recommendation, and the next study of that area" through cited Q&A, trace a finding across years with condition progression tracking and record search, and flag reports that should exist but were not produced. Flags are signals, not verdicts. It does not read images, decide whether a finding was missed, or retrieve records from providers. It runs under SOC 2 and HIPAA with a signed business associate agreement (see security and HIPAA). Self-Service bills 10 cents a deduplicated page, down to 5 cents at volume, duplicates free; Enterprise On-Prem is an annual license.

If you are comparing tools, our guide to medical record review covers what to ask any medical chronology software vendor. See how imaging review fits emergency department failure to diagnose, medical malpractice, expert witness and underwriting work.

What are the parts of a radiology report?

A header with the patient, exam and ordering provider; the indication; the technique; comparison studies; findings; limitations; the impression; recommendations; and the signature with dictation and finalization times.

What is the impression on a radiology report?

The radiologist's conclusion. It should answer the clinical question and carry forward any significant finding. Many clinicians read only this section, so a finding left out of it is easy to miss.

What is the difference between a preliminary and a final radiology report?

A preliminary report is an early read, often overnight, to direct immediate care. The final report is the signed, definitive interpretation. The ACR says preliminary reports should be kept because decisions may have been based on them.

What is an addendum to a radiology report?

A later addition to a signed report, dated separately, such as a correction or a comparison with an outside study. The original text should remain visible.

How long must radiology images and reports be kept?

Hospitals must keep reports and images for at least 5 years under federal rules. Mammography facilities have separate rules, and state law may require longer.

Who is responsible for following up on an incidental finding?

The ACR says the interpreting radiologist should communicate significant unexpected findings and the ordering clinician shares responsibility for obtaining results. Who did what is established from the report, its distribution and the notes that follow.

Can a radiology report prove a finding was missed?

It shows what was reported. Whether something was visible on the images and should have been reported takes a radiologist reviewing the images themselves.

Can AI read radiology reports for a legal case?

AI can extract every finding, impression and recommendation from the report text and put them on a timeline with page citations. It does not replace a radiologist reading the images.

Is it HIPAA compliant to upload imaging reports to an AI tool?

It can be, with a vendor that signs a business associate agreement, holds a SOC 2 report and commits in writing not to train on your data. A consumer chatbot without a BAA is a different matter.

Regulations, the CMS State Operations Manual (Appendix A, revision 248) and the ACR practice parameter were read in full text from primary sources in September 2026, and quoted text is verbatim. Study figures come from the published abstracts. The mock report, patient, physicians, dates and pages in chapters 2, 6 and 7 are hypothetical. Product facts come from this site's product pages. Nothing here is legal or medical advice.

• 42 CFR 482.26: radiologic services, signed reports and 5-year retention.
• 21 CFR 900.12: mammography report content, patient and provider communication, and record keeping.
• CMS State Operations Manual, Appendix A: interpretive guidance at tag A-0553 (radiology records).
• ACR Practice Parameter for Communication of Diagnostic Imaging Findings, revised 2025 (Resolution 9).
• Kim YW, Mansfield LT, "Fool me twice: delayed diagnoses in radiology with emphasis on perpetuated errors", AJR 202(3):465-470, 2014.
• Blagev DP, Lloyd JF, Conner K, et al., "Follow-up of incidental pulmonary nodules and the radiology report", Journal of the American College of Radiology 11(4):378-383, 2014.
• Ruutiainen AT, Scanlon MH, Itri JN, "Identifying benchmarks for discrepancy rates in preliminary interpretations provided by radiology trainees at an academic institution", Journal of the American College of Radiology 8(9):644-648, 2011.
• Whang JS, Baker SR, Patel R, et al., "The causes of medical malpractice suits against radiologists in the United States", Radiology 266(2):548-554, 2013.
• Callen JL, Westbrook JI, Georgiou A, Li J, "Failure to follow-up test results for ambulatory patients: a systematic review", Journal of General Internal Medicine 27(10):1334-1348, 2012.
• Bruno MA, Walker EA, Abujudeh HH, "Understanding and confronting our mistakes: the epidemiology of error in radiology and strategies for error reduction", RadioGraphics 35(6):1668-1676, 2015.