Same scan, different question depending on the stage of your care. Before a problem is identified, a chest X-ray asks: is anything obviously wrong? Before surgery, a CT and a PET-CT ask: where is the cancer and can it be removed? Before agreeing to operate, a VQ SPECT-CT and an echocardiogram ask: can this patient tolerate the operation? After surgery, the X-ray asks: are the lungs recovering well? Dr Lawrence Okiror, Consultant Thoracic and Robotic Surgeon at London Bridge Hospital and The Lister Chelsea, reviews imaging personally at every consultation. Private appointments within 2–3 working days. Self-referrals welcome.
Last reviewed: May 2026 · Dr Lawrence Okiror FRCS(CTh) FRCSEd(CTh) · GMC 6150382
Every scan is requested to answer a specific surgical question — not to describe the lung in the abstract. The question changes at each stage of care.
Tests build on each other. X-ray narrows what needs more detail. CT narrows what needs PET-CT. PET-CT narrows what needs tissue. Each scan asks a different question.
At consultation, scans are opened on screen and reviewed image by image — not summarised from the radiology report. The decision is made with the imaging in front of you.
There is no shortage of imaging information online. NHS pages, radiology society pages, and oncology charities all explain what a CT scan is, how an MRI works, and what radiation dose to expect. This page does something different. It explains what a thoracic surgeon is looking for in each scan — the question being asked, the reason the scan was requested at this point rather than another, and how the answer changes what happens next.
The same CT scan asks one question before a problem is identified, a different question before surgery is offered, and a third question after the operation. The same chest X-ray that screens for an unexplained finding becomes, after a lung resection, a structured check that the remaining lung is recovering. The framing matters. A scan in isolation is just an image; a scan read in context is a decision.
The sections below walk through the imaging journey in the order in which it is usually requested — from the first abnormal X-ray to the post-operative recovery scan — explaining at each stage what the surgeon is looking for, when an additional or different scan is added, and why.
The first chest imaging most people have is a chest X-ray — for a persistent cough, a routine occupational check, breathlessness, or as part of an unrelated assessment. The X-ray is a two-dimensional shadow image of the chest taken in under a minute. It is inexpensive, low-radiation (about 0.02 mSv, the equivalent of three days of background radiation), and an efficient screen for obvious abnormalities — pneumonia, large pneumothorax, sizeable fluid collections, gross emphysema, and substantial tumours.
Its limitation is detail. Small nodules, early interstitial change, and subtle lymph node enlargement are not visible on chest X-ray. If symptoms continue despite a normal X-ray, or if the X-ray itself raises a question, the next test is almost always a CT scan of the chest.
A baseline CT thorax is the workhorse of thoracic imaging. It produces cross-sectional images of every structure inside the chest in under a minute. For a suspected lung nodule, an unexplained shadow on chest X-ray, or symptoms not explained by the X-ray, the CT is what defines whether anything actually needs surgical attention. If you have been told you have a nodule or a shadow, the shadow on a scan and what is a lung nodule pages explain what happens next.
For patients with breathlessness rather than a nodule, the relevant scan is a HRCT — a high-resolution CT of the lung designed to show fine structural detail. HRCT is the scan that defines the pattern of emphysema, identifies pulmonary fibrosis, and assesses small-airway disease. It is the planning scan before emphysema surgery and lung volume reduction (see Emphysema Surgery in 2026).
A CTPA (CT pulmonary angiogram) is a specific CT protocol used to look for blood clots in the lungs (pulmonary embolism), with intravenous contrast timed to the pulmonary arteries. It is not used for routine lung assessment — it answers a specific clinical question when PE is suspected.
Once a lung cancer is suspected or confirmed, the question changes. The CT alone is no longer enough. Staging answers two questions: how big is the cancer and what local structures does it involve, and has it spread anywhere else?
The first scan is usually a CT of the chest, abdomen, and pelvis with intravenous contrast. The contrast highlights blood vessels and helps distinguish a tumour from surrounding lung, lymph nodes from blood vessels, and active liver lesions from benign cysts. The abdomen and pelvis are included because lung cancer can spread to the liver and adrenal glands, and these are checked at the same time as the chest staging.
The second scan, almost always, is a PET-CT. A small amount of radioactive glucose (FDG) is injected; tissues with high metabolic activity light up. Most lung cancers and active lymph nodes show on PET; scarring, granulomas, and benign nodules usually do not. PET-CT identifies lymph nodes that look normal on CT but are involved, and screens the rest of the body for distant spread that CT alone may miss. It does not replace tissue biopsy; it changes the question of where to biopsy, and whether to operate at all.
For Stage II disease and above, and for any patient being considered for radical treatment with neurological symptoms, a brain MRI is added to staging. Lung cancer can spread to the brain even when the primary tumour is small, and MRI is more sensitive than CT for the small metastases that change a treatment plan. The scan itself is painless; gadolinium contrast is usually given.
For a fuller account of how staging informs surgical planning, see Lung Cancer Surgery in 2026 and, for patients with cancer that has already spread to the lung from elsewhere, Cancer Spread to the Lungs.
Each scan narrows what the next one is for. A poorly staged cancer is harder to treat well. Compressing staging too quickly — biopsying before PET, operating before brain MRI — risks missing information that would have changed the operation.
Staging tells you what cancer the patient has. Fitness assessment tells you what operation the patient can have. The two questions are separate and the imaging is different.
The framework for fitness — cardiac risk, operative risk, post-operative breathing — is set out in detail on Fitness for Lung Surgery. What follows is the imaging part of that assessment.
Lung function imaging
A three-dimensional functional lung scan that maps how much of total lung function comes from each region. For patients told their breathing tests are borderline for surgery, the regional picture often changes the answer. Used routinely in emphysema surgery planning; brought across into lung cancer surgery where lung function is a constraint.
Private patients scanned at Guy's and St Thomas' (PMI or self-pay). Read more →
Cardiac imaging
An echocardiogram (cardiac ultrasound) is the routine test — it measures heart function, screens valves, and estimates the pressure in the pulmonary arteries. It is requested before any major lung resection in patients with cardiac history and is part of routine work-up before lung volume reduction surgery in severe emphysema.
A myocardial perfusion scan (MPS) looks for reduced blood flow to the heart muscle — relevant where coronary disease is suspected. A cardiac MRI is reserved for selected cases where the question is muscle viability, complex congenital anatomy, or suspected infiltrative disease.
Beyond lung cancer staging and fitness assessment, specific surgical problems call for specific imaging. Three modalities deserve their own treatment.
Soft tissue, vessels, spine, diaphragm
MRI uses magnetic fields rather than X-rays and excels at soft tissue, structures next to the spine, and the great vessels. In thoracic practice it is used selectively rather than routinely. The scan takes around 45 minutes and is louder and more enclosed than CT — relevant for patients with claustrophobia, who can usually be supported with sedation if needed.
The main thoracic MRI indications:
Diaphragm, fluid, image-guided procedures
Ultrasound uses sound waves rather than radiation and shows images in real time as the probe moves. In thoracic practice it has three distinct uses:
Specialised PET
A DOTATATE PET-CT uses a different tracer (Gallium-68 DOTATATE) to standard FDG PET. The tracer binds to somatostatin receptors expressed by neuroendocrine tumours, including most lung carcinoids. For a confirmed or suspected pulmonary neuroendocrine tumour, DOTATATE PET is more sensitive than FDG PET-CT for defining the extent of disease and identifying additional sites that would change the operation.
Dr Okiror has direct access to DOTATATE PET at both his NHS base (Guy's and St Thomas') and at London Bridge Hospital (private) — the same access on both sides of the practice, which is unusual.
For more on the spectrum of lung neuroendocrine tumours — typical carcinoid, atypical carcinoid, large-cell neuroendocrine carcinoma — and the specialist multidisciplinary route for locally advanced or recurrent disease, see Rare Chest Tumours.
The same chest X-ray that started the journey is now a different test. After lung surgery, Dr Okiror requests a chest X-ray at follow-up to check that the remaining lung has re-expanded properly, that there is no significant collection of fluid (pleural effusion) or air (pneumothorax), and that the operative site is healing as expected. The X-ray is quick, low-radiation, and gives the necessary structural answer at this point.
For lung cancer surveillance, follow-up CT scans are scheduled at defined intervals according to national guidance — typically every six months for the first two years and yearly thereafter, adjusted to the stage and pathology of the resected cancer. The role of the surveillance CT is to detect recurrence early and to monitor the contralateral lung for new primary disease, which screen-detected cohorts have shown to be a real risk.
For pulmonary metastasectomy, restaging CT before each operation is the rule. See Pulmonary Metastasectomy.
For the recovery pathway after lung surgery — prehab, day-one mobilisation, follow-up clinic structure — see Recovery After Lung Surgery.
Three practical questions come up at almost every consultation, and they deserve a direct answer.
Radiation. Cumulative dose across staging and follow-up matters more than any single scan. A chest X-ray is around 0.02 mSv (three days of background). A standard CT thorax 5–7 mSv. A staging CT thorax-abdomen-pelvis with contrast around 10 mSv. A PET-CT around 12–15 mSv. MRI and ultrasound use no ionising radiation. For younger patients in particular, the question of dose is real but should not preclude appropriate imaging — the risk of an inadequately staged or under-monitored cancer is higher than the radiation risk of the scan that defines the treatment.
Contrast. Intravenous contrast is used for staging CT to define vessels and lymph nodes. Patients with reduced kidney function or previous contrast allergy need a tailored protocol. Gadolinium contrast (used in MRI) is generally well-tolerated. Fasting is required before PET-CT but not before most CT scans.
Over-imaging. Every scan should answer a specific clinical question. Repeating scans for reassurance, scanning before the previous result is interpreted, or imaging without a defined next step are common patterns that add radiation and anxiety without changing the decision. At consultation, Dr Okiror requests only the imaging that will change what happens next — and explains, in the room, why each scan is being asked for.
If you have a scan and want an independent surgeon's read — opening the imaging directly rather than relying on the written report — most patients are seen within 2–3 working days.
Book a Consultation →Or call Jo Mitchelson:
020 7952 2882
Bringing your imaging to the consultation — on disc, digitally, or with access from the originating hospital — allows the scans to be reviewed directly rather than summarised from the written report. Appointments at London Bridge Hospital and The Lister Chelsea within 2–3 working days. Self-referrals welcome.
Jo Mitchelson, PA · 020 7952 2882 · pa@lungsurgeon.co.uk
St Thomas’ Hospital #1 UK · Guy’s Hospital #2 UK · London Bridge Hospital #10 UK · Newsweek World’s Best Hospitals 2026
Stage-by-stage pathway from screening to surgery and beyond.
Emphysema Surgery in 2026EBV and LVRS — HRCT and VQ SPECT-CT are the planning scans.
Borderline Lung FunctionVQ SPECT-CT regional function mapping when spirometry alone is not enough.
Fitness for Lung SurgeryThe three-part framework: cardiac risk, operative risk, post-operative breathing.
Rare Chest TumoursCarcinoids, the wider neuroendocrine spectrum, and rare airway tumours — including DOTATATE PET in staging.
Specialist Second OpinionIndependent review of imaging and treatment plan within 2–3 working days.