Undiagnosed: One Patient, Five Scans and a Diagnosis Nobody Expected

This is a constructed clinical teaching scenario. The patient is fictional, but the investigation pathway, imaging principles and nursing considerations are based on UK practice. You are not supposed to know the diagnosis at the beginning. That is the point.

Meet Maya, 29.

She is a second-year student nurse, currently juggling university work, placement shifts and the usual attempt to have a life somewhere in between. She goes to the gym when she can, has never smoked and has no major medical history. For the last eight weeks she has had a cough that will not quite disappear. At first she blamed a cold. Then long placement days. Then the fact that everyone seems to be coughing at some point.

More recently she has noticed that climbing stairs leaves her more breathless than usual. She has lost around 4 kg without trying and feels tired in a way that sleep does not seem to fix. She has even caught herself doing what healthcare students are particularly good at: explaining away her own symptoms because she can think of a less frightening reason for each one.

Today she develops a small amount of haemoptysis: blood-streaked sputum.

That is what finally brings her back for assessment.

There is an uncomfortable twist here. Maya has spent the last two years learning how to recognise deterioration, ask patients about symptoms and understand investigations. Now she is the person sitting on the examination couch answering the questions.

If Maya were your course-mate, would cancer be your first thought?

Probably not. She is 29. She has never smoked. She looks like somebody you might sit beside in a lecture, meet on placement or message the night before an assessment asking whether you have understood the assignment properly.

But clinical assessment cannot stop at what seems statistically likely for someone's age. Maya has persistent respiratory symptoms, unexplained weight loss and haemoptysis. Something needs explaining.

And this is where imaging begins.

The first image: a chest X-ray

Maya is sent for a chest X-ray.

Before we look at the result, stop for a second. Why start with an X-ray when CT can produce much more detailed images?

Because the most detailed test is not automatically the best first test. A chest X-ray is quick, widely available and uses a relatively low dose of ionising radiation. It can identify abnormalities such as consolidation, pleural effusion, pneumothorax and some masses that may explain respiratory symptoms. There is an important detail in Maya’s case, though: she is 29. NICE NG12 recommendations for an urgent chest X-ray based on symptoms associated with possible lung cancer are largely age-based and apply to people aged 40 and over. Maya therefore should not be presented as automatically meeting that standard age-based pathway. In her case, imaging follows clinical assessment and concern about a persistent, unexplained combination of cough, breathlessness, weight loss and haemoptysis. Her age makes lung cancer less likely; it does not make significant pathology impossible.

An X-ray works by passing ionising electromagnetic radiation through the body towards a detector. Different tissues attenuate, or reduce, the X-ray beam by different amounts.

Air in the lungs allows much of the beam through and therefore appears relatively dark. Dense structures such as bone absorb more X-rays and appear lighter. Soft tissues sit between those extremes.

But there is a limitation hiding inside that simplicity: a standard chest X-ray compresses three-dimensional anatomy into a two-dimensional projection. Structures overlap. A lesion can be obscured by the heart, diaphragm, ribs or other tissues. And an abnormality on an X-ray does not automatically tell you what that abnormality is.

Maya's report returns:

Chest X-ray: focal right upper-zone opacity with right hilar prominence. Further cross-sectional imaging advised.

That is not a diagnosis.

An opacity simply means an area looks more opaque than expected. Infection could do that. A mass could do that. Other pathology could do that.

So the X-ray has done its job. It has answered one question: is there something abnormal enough here to investigate further?

The answer is yes.

Now the clinical question changes.

Why CT comes next

Following the abnormal chest X-ray, Maya is referred urgently for specialist assessment and undergoes contrast-enhanced CT of the chest, including the liver, adrenal glands and lower neck. NICE recommends this imaging before biopsy when lung cancer is suspected because CT helps define the primary lesion, assess lymph nodes and look for evidence of metastatic disease while also helping the team decide the most appropriate method of obtaining tissue.

This is where students sometimes think CT is simply a “better X-ray”. It is more useful to understand what has changed.

CT still uses X-rays, so it still involves ionising radiation. But instead of producing one projection through the body, an X-ray tube rotates around the patient while detectors collect information from many angles. A computer reconstructs those data into cross-sectional images.

Think of the difference like this: the chest X-ray looked through Maya's chest all at once. CT lets the team examine reconstructed slices through it.

That dramatically reduces the problem of structures being superimposed on one another and allows much more precise assessment of the size and location of an abnormality, nearby structures, lymph nodes and other organs.

This is why CT commonly follows an abnormal chest X-ray when lung cancer is suspected.

Maya's CT is performed with iodinated intravenous contrast.

Why contrast?

Contrast changes the attenuation of X-rays in blood vessels and tissues, helping particular structures and abnormalities stand out from their surroundings. It can improve assessment of vessels, lymph nodes, masses and organ enhancement.

From a nursing perspective, “going for CT” therefore involves more than arranging transport. The exact preparation depends on the examination and local protocol, but the team may need to know about pregnancy possibility, previous reactions to contrast media, renal function, medicines or other relevant risks, and whether suitable IV access is available.

And a useful terminology point: avoid casually writing “iodine allergy”. Iodine is an essential element and is not itself an allergen in the way that phrase implies. What matters clinically is whether the patient has previously reacted to a particular contrast agent, what happened and how severe the reaction was.

Then Maya's CT report arrives.

CT chest: 3.4 cm right upper-lobe lesion with enlarged right hilar and mediastinal lymph nodes. Small right pleural effusion. A mildly enlarged right supraclavicular lymph node is also noted. No definite liver or adrenal metastases identified on this examination.

Now we know much more.

But we still do not know what the lesion is.

CT can show anatomy beautifully. It can tell us that a lesion exists, where it is, its dimensions and what else looks abnormal. It cannot look at an image and provide the cellular diagnosis required to determine exactly what a tumour is.

This is the point where imaging and pathology meet.

The scan that helps obtain tissue: ultrasound

The enlarged supraclavicular lymph node seen on CT can be assessed with ultrasound and, if suitable, sampled.

This is a very different imaging technology.

Ultrasound does not use ionising radiation. The transducer sends high-frequency sound waves into the tissues and detects returning echoes. The timing and strength of those echoes are used to construct an image in real time.

Why is “real time” important here?

Because the operator can see the lymph node, surrounding tissues, blood vessels and the needle as the procedure takes place. Ultrasound is therefore not just diagnostic imaging; it can be used to guide procedures safely and accurately.

For Maya, the node provides a potential route to tissue without immediately having to pass a needle through lung tissue.

The ultrasound confirms an abnormal-appearing right supraclavicular node and an ultrasound-guided core biopsy is performed.

At this point Maya asks the question nearly every patient in this situation wants answered:

“So does that mean it's cancer?”

The answer is still: we do not know yet.

Suspicious imaging is not the same thing as histological confirmation.

The sample goes to pathology.

While waiting, the respiratory multidisciplinary team reviews the imaging and considers what further staging information would be needed if malignancy is confirmed.

A few days later the pathology result returns.

Biopsy: metastatic adenocarcinoma consistent with a primary lung origin.

For the first time, Maya has a tissue diagnosis.

She has lung cancer.

At 29.

As a second-year nursing student, she understands enough medical language to recognise some of the words before the clinician has finished explaining them. But knowing terminology is not the same as being prepared to hear it applied to yourself. From this point, Maya is a patient first. Her healthcare knowledge may affect the questions she asks, but it must never be assumed that she understands, is coping, or needs less explanation than anybody else.

And this is exactly why the scenario began with her age and smoking history. Lung cancer is strongly associated with increasing age and tobacco exposure, but neither youth nor never-smoking status makes it impossible. A student should use epidemiology to understand risk, not to dismiss unexplained clinical findings.

Now another question immediately replaces the first one.

How far has it spread?

PET-CT: anatomy meets metabolic activity

Maya is referred for PET-CT as part of staging and treatment planning.

PET-CT is actually two imaging approaches combined.

The CT component provides anatomical information. The PET component provides information about the distribution of a radioactive tracer and therefore about aspects of tissue physiology and metabolism.

A commonly used tracer in oncology is fluorodeoxyglucose, or FDG, a glucose analogue labelled with the positron-emitting radionuclide fluorine-18. Tissues with increased glucose metabolism may accumulate more FDG.

When the radionuclide decays it emits a positron. After travelling a very short distance, the positron interacts with an electron. Their annihilation produces two photons travelling in approximately opposite directions. The PET scanner detects coincident photon events and reconstructs where tracer activity is occurring.

You do not need to become a nuclear physicist to understand the clinical point: PET tells us about tracer activity; CT tells us where that activity is anatomically.

This is why PET-CT can be so useful in cancer staging. It can reveal metabolically active sites that alter the understanding of disease extent and therefore treatment planning.

But there is a trap.

FDG uptake does not equal cancer.

Inflammation and infection can also be metabolically active. PET findings have to be interpreted in clinical and anatomical context. A bright area on PET is not a microscopic diagnosis.

Maya also discovers that preparation matters. PET departments commonly ask patients to avoid eating for a period before FDG imaging and to avoid strenuous exercise beforehand. Blood glucose can affect image quality and protocols may need adjustment for people with diabetes. Pregnancy and breastfeeding status are also important because radioactive tracers are involved.

Her PET-CT report shows:

PET-CT: intense FDG uptake in the known right upper-lobe primary lesion and involved right hilar, mediastinal and supraclavicular nodes. No convincing FDG-avid distant extracranial metastatic disease.

That sounds almost reassuring.

Almost.

Because during her clinic review Maya mentions something she had not thought important before.

For the last fortnight she has had intermittent headaches. Yesterday, while typing, she briefly felt that her left hand was “not doing what I wanted it to do”. It lasted less than a minute.

Now there is a new clinical question.

PET-CT has provided valuable staging information, but Maya has now introduced a new clinical problem: focal neurological symptoms and headaches in someone with a newly diagnosed malignancy. The brain therefore requires dedicated imaging. NICE guidance for suspected brain metastases allows CT of the head followed by MRI if CT is normal, or MRI as the initial diagnostic investigation. In Maya’s scenario, the specialist team proceeds directly to contrast-enhanced MRI because detailed assessment for intracranial metastatic disease is required.

So Maya is booked for an MRI of the brain.

MRI: when soft-tissue detail becomes the question

MRI feels completely different from the scans Maya has already had because it does not use X-rays.

It uses a powerful magnetic field, radiofrequency energy and magnetic field gradients to generate images based largely on the behaviour of hydrogen nuclei, particularly the abundant hydrogen in body water and fat.

In the scanner's magnetic field, a small excess of hydrogen nuclei align with that field. Radiofrequency pulses perturb that alignment. As the nuclei return towards equilibrium, they produce signals that can be spatially encoded and reconstructed into images.

Different tissues return towards equilibrium at different rates. By changing the sequence parameters, MRI can emphasise different tissue characteristics. This is why you hear terms such as T1-weighted, T2-weighted, diffusion-weighted imaging and FLAIR. They are not different machines; they are different ways of interrogating tissue signal.

For students, the practical takeaway is that MRI offers excellent soft-tissue contrast, particularly in structures such as the brain and spinal cord.

But no ionising radiation does not mean “no safety issues”.

The magnetic field is extremely powerful and is always treated as a major safety consideration. Patients require careful screening for implants, devices, previous surgery, possible metallic foreign bodies and other hazards. Some devices are MR Safe, some MR Conditional and some may be unsafe. “The patient has metal in them” is not enough information to make the decision.

Claustrophobia matters too. So does the patient's ability to lie still. If gadolinium-based contrast is required, the imaging team follows current contrast-safety guidance and considers individual risk factors. Routine renal-function testing is not required before every administration of a modern gadolinium-based contrast agent, so preparation should follow the specific agent, clinical circumstances and local radiology protocol.

Maya completes the scan.

The report returns:

MRI brain with contrast: solitary 8 mm enhancing lesion in the right frontal lobe with mild surrounding oedema, suspicious for a metastasis.

One small lesion has changed the picture again.

And notice what happened across the pathway. The X-ray was not “wrong” because it could not stage Maya's cancer. CT was not “incomplete” because it could not provide histology. Ultrasound was not “basic” because it was used to guide a biopsy. PET-CT was not “better than MRI” because it surveyed metabolic activity throughout much of the body.

Each test answered a different question.

The result: what does Maya actually have?

Maya's final diagnosis is lung adenocarcinoma with regional nodal involvement and a solitary brain metastasis. The precise TNM stage and treatment plan would be determined by the specialist multidisciplinary team using the complete imaging, pathology, molecular results and clinical assessment.

We are deliberately going to stop the staging discussion here.

Why? Because Maya's story is going to continue in a separate care-planning teaching case. There we can take the information collected during this diagnostic pathway and work through TNM staging properly, performance status, molecular testing, treatment intent, symptoms, psychosocial assessment, nursing priorities, goals, interventions, evaluation and what a genuinely person-centred plan looks like for a 29-year-old student nurse whose life has suddenly changed direction.

That separation matters educationally. This article is about understanding why different imaging modalities were chosen and what each investigation contributed. The next case will ask a different question: now that we know what is happening, how do we plan Maya's care?

And there is another important modern part of the story.

Because Maya has non-small-cell lung adenocarcinoma, tumour tissue can undergo molecular testing for actionable alterations and biomarkers that may influence systemic treatment. The diagnosis is no longer simply “lung cancer, therefore chemotherapy”. Histological subtype, stage, molecular characteristics, performance status and the patient's own preferences all influence management.

That discussion belongs to the next stage of Maya's care, but it matters because it shows why obtaining good-quality tissue was not an administrative step between scans. The biopsy provides information that imaging cannot.

Now rewind the whole pathway

Maya started with symptoms, not a diagnosis.

The chest X-ray was a sensible first investigation because it could rapidly identify a significant thoracic abnormality. It told the team that something was wrong, but the two-dimensional projection could not characterise or stage it adequately.

The contrast-enhanced CT turned that projection into detailed cross-sectional anatomy. It defined the lung lesion, demonstrated abnormal lymph nodes, identified a pleural effusion and showed an accessible supraclavicular node. But suspicious anatomy was still not histology.

Ultrasound then answered a procedural question: can we see and safely target that node in real time to obtain tissue? The biopsy converted suspicion into a pathological diagnosis.

PET-CT then asked a different question: where else is metabolically active disease apparent, and how might that alter staging and treatment planning?

Finally, new neurological symptoms created another question. MRI was used because detailed brain imaging was now clinically necessary, and it demonstrated the small intracranial lesion.

Five imaging technologies did not mean five attempts to find the same answer.

They were five different tools answering five different questions.

What were you doing as the student nurse during all of this?

There is another layer to this question now: Maya could have been standing beside you on placement a few weeks ago.

That is worth remembering. Healthcare professionals and students become patients too. Familiarity with clinical environments does not remove fear, uncertainty, loss of control or the need for clear explanations. In fact, partial clinical knowledge can sometimes create its own anxiety because Maya knows enough to understand what some possibilities mean while still not knowing what will happen to her.

When Maya is first assessed, somebody needs to notice that “young and probably fit” does not explain haemoptysis, persistent cough, weight loss and breathlessness. Observations, symptom assessment, escalation and accurate documentation matter before the first image exists.

Before CT, somebody needs to check the requested preparation has happened, communicate relevant history and make sure Maya can safely get to and through the scan. If contrast is planned, the appropriate screening and local protocol need to be followed.

Before the ultrasound-guided biopsy, Maya needs an explanation of what is happening, appropriate consent from the practitioner performing the procedure, preparation according to local protocol and support with the fact that she is undergoing a biopsy for possible cancer at 29.

After an invasive procedure, nursing assessment matters. Pain, bleeding, observations and procedure-specific complications are not somebody else's problem because the scan has finished.

Before PET-CT, preparation affects the quality and safety of the investigation. Has Maya followed the fasting instructions? Is pregnancy possible? Is she breastfeeding? Does she have diabetes or another issue that affects preparation? Has she exercised heavily despite being asked not to? These are not trivial questions when tracer distribution and radiation safety matter.

Before MRI, the safety screening deserves respect. Never reassure somebody that an implant is “probably fine”. The exact device and its MR conditions need to be established by the imaging team. You also need to think about pain, anxiety, claustrophobia, mobility and whether the patient can tolerate lying still.

And throughout all of it, Maya is still a person waiting to find out whether she has cancer.

She may ask you what the scan shows. She may stare at the radiographer's face looking for clues. She may see something on a monitor and ask whether it is the tumour.

You do not diagnose from the screen or interpret images beyond your role. You can acknowledge the anxiety, explain the process you understand, check what she has been told and make sure questions reach the appropriate clinician.

“I don't know yet, but I'll find out when the team expects the report and make sure you know what happens next” is much safer and kinder than guessing.

One last thing: imaging has risks, but that does not make it dangerous by default

X-ray, CT and PET-CT involve ionising radiation. MRI and ultrasound do not.

That distinction matters, but it should not turn into “radiation scan bad, non-radiation scan good”.

Clinical imaging is justified by weighing the expected benefit against the risk. CT may expose a patient to more ionising radiation than a plain X-ray, but in a patient where rapid cross-sectional imaging can identify serious disease, that information may be extremely valuable.

MRI avoids ionising radiation but has its own safety requirements, availability constraints and practical limitations. Ultrasound is excellent for many questions but sound does not travel well through air and is limited by factors such as depth, overlying structures and the acoustic window. PET-CT can reveal metabolically active disease but involves a radiotracer, CT radiation and limitations in specificity.

There is no universally “best scan”.

There is a best investigation for the clinical question in front of the team, for this particular patient, at this particular point in the pathway.

The part I want you to remember

If you meet a patient who has had an X-ray, then CT, then ultrasound, then PET-CT, then MRI, do not assume the team keeps repeating tests because nobody can decide what is happening.

Ask yourself:

What question did the last investigation answer, and what question is still unanswered?

That single habit will make medical imaging much easier to understand.

Maya's X-ray found an abnormality. CT mapped the anatomy. Ultrasound helped obtain tissue. Pathology named the disease. PET-CT mapped metabolic disease. MRI answered the new neurological question.

And the diagnosis only became clear because all of those pieces were interpreted together.

For Maya, however, diagnosis is not the end of the story. It is the point at which care planning begins.

References

National Institute for Health and Care Excellence (NICE). Lung cancer: diagnosis and management (NG122). Available at: NICE NG122.

National Institute for Health and Care Excellence (NICE). Suspected cancer: recognition and referral (NG12). Available at: NICE NG12.

NHS. Lung cancer: diagnosis. Available at: NHS lung cancer diagnosis.

NHS. PET scan. Available at: NHS PET scan.

NHS. CT scan. Available at: NHS CT scan.

NHS. MRI scan. Available at: NHS MRI scan.

NHS. Ultrasound scan. Available at: NHS ultrasound scan.

This fictional scenario is for student learning and placement preparation. It does not represent one real patient's experience and does not replace clinical assessment, local policy, specialist advice or supervision.