A radiology report follows a predictable structure, and once you know what each section does, you can pull the key information quickly. The most important section for you is the impression at the very bottom, which contains the radiologist’s bottom-line interpretation. Everything above it builds toward that conclusion. Under federal rules stemming from the 21st Century Cures Act, health systems must release imaging results to patient portals immediately after the report is finalized, so many people now see these reports before they’ve spoken with their doctor.
The Six Sections of a Standard Report
The American College of Radiology divides a radiology report into six sections: examination, history/indication, technique, comparison, findings, and impression. Not every report uses all six, and some combine them, but the general flow is the same regardless of whether you had a CT scan, an MRI, an X-ray, or an ultrasound.
Examination tells you what type of scan was performed and which body part was imaged. It might say something like “CT abdomen and pelvis with contrast.”
History/Indication is a brief note about why the scan was ordered. This comes from your referring doctor and might read “abdominal pain, rule out appendicitis.” The abbreviation “r/o” means “rule out.”
Technique describes the technical details of how the scan was performed, such as whether contrast dye was used or how the images were acquired. This section is written for the ordering physician and rarely contains anything you need to act on.
Comparison lists any prior imaging the radiologist reviewed alongside your current scan. If it says “Comparison: CT abdomen 3/15/2024,” the radiologist looked at that earlier scan to check for changes. If it says “No prior studies available for comparison,” they’re interpreting your images in isolation.
Findings is the longest section. It’s a detailed, organ-by-organ description of everything the radiologist sees on the images. This section contains the raw observations before the radiologist draws conclusions.
Impression is the summary at the end. It answers the clinical question, highlights the most important findings, and sometimes includes recommendations for follow-up. If you only read one section, read this one.
Findings vs. Impression
The distinction between these two sections trips up a lot of people. The findings section describes what the radiologist observes: sizes, shapes, densities, and locations of structures. The impression section interprets those observations into a diagnosis or differential diagnosis. For example, the findings might describe “a 2 cm low-density lesion in the right lobe of the liver,” while the impression might say “likely hepatic cyst, benign.”
Many referring physicians skip straight to the impression, and you can do the same. However, the findings section is useful if you want to understand the specific details behind the conclusion, or if you’re tracking something over time and want to compare measurements from one scan to the next. Occasionally, a finding mentioned in the body of the report doesn’t make it into the impression, particularly if the radiologist considered it minor or was focused on a more urgent issue.
Common Terms and What They Mean
Radiology reports are full of terms that sound alarming but are often neutral or even reassuring. Here are the ones you’ll encounter most:
- Unremarkable means normal. Nothing unusual was seen. This is good news.
- Stable means unchanged compared to a prior scan. A finding that is stable over time is generally less concerning than one that is growing or changing.
- Acute means new or recent.
- Chronic means long-standing or old.
- Nonspecific means the finding could have several possible explanations and isn’t pointing clearly to one diagnosis.
- No acute abnormality means nothing new or urgent was found, though there may be older, known changes present.
You may also see abbreviations scattered throughout. “CXR” is a chest X-ray. “SOB” stands for shortness of breath. “DX” means diagnosis. “MI” is a heart attack. “TIA” is a small stroke. These are shorthand carried over from the clinical notes your doctor provided to the radiologist.
Terms That Change by Scan Type
Each imaging modality uses its own vocabulary to describe how things look, and knowing which words go with which scan helps you decode the findings section.
On a CT scan, the radiologist describes structures by their density or attenuation. Dense structures like bone appear bright on the image and are called “hyperdense” or “high attenuation.” Less dense structures, like fluid or fat, appear darker and are “hypodense” or “low attenuation.” “Isodense” means something blends in with the surrounding tissue. You may occasionally see a measurement in Hounsfield units (HU), which is a precise number assigned to tissue density on CT.
On an MRI, the equivalent terms are based on signal intensity. Bright areas are “hyperintense” or “high signal,” dark areas are “hypointense” or “low signal,” and areas that match surrounding tissue are “isointense.” Because MRI uses different pulse sequences (often called T1 and T2), a structure can appear bright on one sequence and dark on another. The radiologist uses these patterns to narrow down what a finding is made of.
On an ultrasound, the vocabulary is about echogenicity, which describes how much sound a structure bounces back. “Hyperechoic” means bright (reflects a lot of sound). “Hypoechoic” means dark (reflects little sound). “Anechoic” means completely black, which typically indicates fluid, like the inside of a cyst. “Acoustic shadowing” refers to a dark streak behind a very dense object like a gallstone or kidney stone, and it’s actually a helpful clue that confirms the stone is there.
On a nuclear medicine scan, such as a bone scan or thyroid scan, the radiologist describes “uptake” of a radioactive tracer. “Increased uptake” means an area is absorbing more tracer than expected, which can signal inflammation, infection, or a tumor. “Decreased uptake” means less tracer than expected in that area.
Incidental Findings
Modern imaging is highly detailed, and scans frequently pick up things that have nothing to do with the reason you were scanned. These are called incidental findings, or sometimes “incidentalomas” when they involve a small mass. A CT scan done for kidney stones, for example, might note a small nodule in the lung or a cyst on an adrenal gland.
Most incidental findings are benign. The radiologist may describe them and then note something like “likely benign, no follow-up needed” or “recommend follow-up in 12 months.” These recommendations are based on established guidelines. For lung nodules, the Fleischner Society guidelines dictate follow-up timelines based on nodule size and your risk factors. A solid nodule smaller than 6 mm in a low-risk patient typically needs no follow-up, while larger or growing nodules may require repeat imaging at intervals of 6 to 24 months. If your report mentions a follow-up recommendation for an incidental finding, it’s worth confirming with your doctor that the follow-up gets scheduled.
Standardized Scoring Systems
For certain types of imaging, radiologists use standardized scoring systems that assign a number reflecting how suspicious a finding looks. These scores are designed to make reports more consistent across different radiologists and institutions. The most common ones are:
- BI-RADS for breast imaging (mammograms, breast MRI, breast ultrasound)
- TI-RADS for thyroid ultrasound
- PI-RADS for prostate MRI
- LI-RADS for liver imaging
- Lung-RADS for lung cancer screening CT
These systems use a numbered scale where lower numbers mean lower suspicion and higher numbers mean higher suspicion. BI-RADS is the most widely known and the one you’re most likely to encounter.
BI-RADS Categories Explained
BI-RADS scores range from 0 to 6. A score of 1 is completely normal. A score of 2 means something was seen, like a benign cyst or calcification, but it’s definitively not cancer. Both categories call for routine screening on your normal schedule.
A BI-RADS 3 means a finding that has a very low chance of being cancer (2% or less) but should be monitored with follow-up imaging every 6 to 12 months for at least two years. A BI-RADS 4 indicates a suspicious finding that warrants a biopsy. This category is subdivided: 4A carries a 2% to 10% likelihood of cancer, 4B is 10% to 50%, and 4C is 50% to 95%. A BI-RADS 5 means the finding is highly suspicious, with at least a 95% chance of being cancer, and biopsy is strongly recommended.
BI-RADS 0 simply means the evaluation is incomplete and additional imaging is needed before a score can be assigned. This is common and not a reason to panic. BI-RADS 6 is only used when cancer has already been confirmed by biopsy and the scan is monitoring treatment response.
How to Use Your Report Effectively
Start with the impression. Read it first to get the radiologist’s overall interpretation. If the impression says “no acute findings” or lists everything as unremarkable, you can feel reassured. If it includes a differential diagnosis (a list of possible explanations), the first item listed is typically considered the most likely.
Next, check for any recommendations. These usually appear at the end of the impression and might suggest follow-up imaging, a biopsy, or clinical correlation (meaning your doctor should factor in your symptoms and exam to decide next steps). Write these down so you can discuss them at your appointment.
If you want more detail, read the findings section organ by organ. Look for words like “stable,” “unchanged,” and “unremarkable” as reassuring markers. Flag anything described as “new,” “enlarging,” “suspicious,” or “concerning” for discussion with your doctor.
Keep in mind that radiologists interpret images without examining you. They don’t know your full medical history the way your treating doctor does. Phrases like “clinical correlation recommended” or “correlate clinically” mean the radiologist is flagging something that needs to be interpreted in context, and your doctor is the one who provides that context.