What do the words in a lung CT report mean?

A lung CT report is full of words that are routine for the radiologist and frightening for the patient. First, an important point: a word in a report means “something was seen”, not “a disease was diagnosed”. The report is written by a radiologist, and what it means for you is for your treating doctor to decide. The ALA also says always talk to your doctor to understand your own result.

What parts does a report have?

The ALA describes the parts of a report like this:

• Examination: the CT scan, with or without contrast (an injected dye).
• Technique: how it was done.
• Comparison: whether it was compared with earlier imaging. This is why you should bring old reports and films to your visit.
• Findings: everything that was seen, including size and appearance.
• Impression: the radiologist’s summary of the interpretation. If you are short of time, read this part first and ask about it.
• Recommendation: the next step that is suggested.

Nodule

The ALA defines a nodule as “a small mass of dense tissue in the lung” that shows up as a white spot on an X-ray or CT scan. CUH (a UK hospital leaflet) says it is usually smaller than one centimetre, that nodules are “very common” and are often found by chance, on an X-ray or CT scan taken for another reason.

A nodule is usually benign

The ALA says most nodules are benign, meaning not cancer. CUH says about 90 percent. A nodule can come from a scar, an earlier infection (such as pneumonia or TB), inflammation or irritants in the air (ALA, CUH). In a small percentage of cases it is cancer, and sometimes the cause is not found. That is why follow-up is done.

A small, unchanging, smooth, round and solid nodule looks more likely to be benign. Growing, an uneven or spiky edge, and being part-solid or non-solid make the appearance more concerning (ALA). That means a sign for further assessment, not a diagnosis of cancer. The ALA also says doctors weigh this appearance together with your overall health.

What happens after a nodule?

• Often just follow-up with CT scans. The ALA says for a benign or slow-growing nodule a CT scan may be repeated every few months to look for growth, and on its report guide page it gives repeat imaging at 3, 6 or 12 months as an example. CUH says the second CT scan is about 3 to 6 months later and several scans may be taken over one to four years. If the nodule does not grow over the set period (usually one to two years), it is regarded as benign and usually no treatment is needed.
• The timing is set by your doctor. CUH says specialists set the time of the next CT scan from the CT result and risk factors. The ALA also says lung specialists use special guidelines and take into account size, shape, overall health and risk factors. So your plan will differ from someone else’s, and the intervals above are only examples.
• If it grows, CUH says a PET scan or biopsy may be needed. The ALA also says a biopsy is sometimes suggested. That means further assessment.
• Keep up the follow-up even without symptoms, and tell your doctor if you develop a cough, blood-stained phlegm, breathlessness, or pain in the chest or shoulder (CUH).

Density: solid, ground glass, part-solid

The ALA describes nodules by density:

• Solid: dense and white.
• Non-solid or ground-glass: hazy and paler (fuzzy). The name comes from frosted glass.
• Part-solid: has both a solid part and a ground-glass part.

These words describe only the appearance, not the cause. The ALA suggests asking your doctor: “How many millimetres is my nodule, and is it solid, part-solid or ground glass?” That is why a doctor weighs the appearance together with size, change over time and your history.

Other words about a nodule’s appearance

• Size: the ALA says it is written in millimetres (and sometimes volume).
• Edge: smooth, bumpy or spiculated. Spiculated means the edge has spikes (ALA).
• Calcification: deposits of minerals in the nodule. The ALA says its pattern (complete, central, popcorn or ring) helps the radiologist guess the cause.
• Fat: sometimes a report says a nodule contains fat (ALA).
• Change: “unchanged”, “new”, “larger” or “smaller” (ALA). This is why comparison with an earlier CT scan matters.

Other words you see in a report

• Lymph node: the ALA describes these as bean-shaped organs in the chest. If the report mentions a lymph node, the ALA says to ask your doctor what the lymph node finding means. The report may also give its location, for example the space between the two lungs (mediastinum).
• Pleural effusion: the ALA describes it as too much fluid collecting between the lung and the chest wall.
• Pleura: the membrane covering the lung and chest wall. “Juxtapleural” means near this membrane (ALA).
• Emphysema: WHO and the NHS describe it as damage to the air sacs of the lung that is part of COPD. The NHS says COPD is permanent damage, but the word alone is not a final diagnosis. The doctor reads the finding together with your symptoms and spirometry.
• Bronchiectasis: the NHS says the airways widen after inflammation and mucus collects. The NHS says a CT scan often confirms it, and it is usually not curable but treatment controls the symptoms.
• Scarring or fibrosis: the NHS and NHLBI speak of scar tissue in the lung, and the NHS says that in conditions such as lung fibrosis a CT scan is used to see the scarring. NHLBI says that in interstitial diseases lung tissue becomes stiff and thick. If these words are in your report, what they mean is for your doctor to say after a full assessment, not the word itself.
• Contrast: a dye sometimes injected into a vein so structures show up better (NHS and NHLBI).
• Lung-RADS: the ALA describes it as a screening tool that helps the doctor choose the next step, and it may appear in a screening report. Its number must be explained to you by your doctor.

If you cannot find a word in this list (for example “consolidation” or “infiltrate”), ask your doctor.

Questions the ALA suggests asking your doctor

• How many millimetres is the nodule, and is it solid, part-solid or ground glass?
• Is it new, larger, unchanged or smaller?
• What does the pattern of calcification or fat show?
• Does my report have a Lung-RADS category and what does it mean?
• Should I have repeat imaging? What kind and when?
• Is a biopsy needed? Why or why not?
• Is there a lymph node or pleural finding I should know about?

Write the questions down before the visit.

Final reminders

• An incidental finding on a CT scan is common and most nodules are benign, but follow-up is set by your doctor and should not be skipped because it is “probably fine”.
• If you smoke cigarettes or hookah, or used to, this affects the follow-up plan (the ALA counts risk factors among the doctor’s considerations). Telling your doctor is not blame, it only makes the plan more accurate.
• Do not interpret your CT result on the internet without your doctor. This page only helps you ask better questions.
• If you have sudden breathlessness, blood-stained phlegm or chest pain, do not wait for follow-up. See the guide “When to call urgently”.