Suspected phaeochromocytoma or paraganglioma

Endocrine Society PPGL guideline 2014; ACR AC Adrenal Mass 2021

Imaging follows biochemistry, never precedes it. Once catecholamine excess is confirmed, the task is locating a tumour that is adrenal in most cases but can lie anywhere along the sympathetic chain — so coverage, not adrenal-specific protocol, is the vetting decision.

Biochemically confirmed or strongly suspected catecholamine excess, an adrenal lesion with imaging features suggesting phaeochromocytoma, or surveillance in a known genetic predisposition syndrome.

Referenced decision support — confirm against your local protocol.

Decision support, not a directive. Protocols and timings shown are typical published ones — your local protocol takes precedence, and the vetting radiologist decides.

The request in front of you

Everything is optional. Leave a field alone and the answer assumes nothing — the verdict updates as you go.

Study requested

What the referrer actually asked for. It is evidence of intent, not a constraint on the right answer.

Contrast as written

What the request form says, not what it should say.

Age

Pick a band, or type an exact age if it matters.

years

Pregnancy status

Renal risk factors

The question a vetter can actually answer from the request. An explicit “none known” is a real answer, and it removes checks rather than deferring them.

Previous contrast reaction

The pathway — tap anything already done

Marking a study complete moves the answer on. A patient arrives partway through a pathway far more often than at the start of one.

Accept as requested

CT Abdomen and Pelvis — Portal Venous Phase

CT Abdomen and Pelvis

What we'd amend, and why

Coverage is the reason this is a whole abdomen and pelvis study rather than an adrenal one. Most of these tumours are adrenal, but a substantial minority arise in the organ of Zuckerkandl, the bladder wall or anywhere along the para-aortic sympathetic chain, and a protocol targeted at the adrenal beds will simply not include them. Contrast-enhanced imaging is what shows the characteristically avid, often heterogeneous and necrotic enhancement pattern, and modern CT resolves lesions down to a few millimetres. Non-ionic contrast can be given without routine alpha blockade.

Nothing needs resolving before this goes ahead. Routine checks below are owned downstream.

How was this decided?

pathwaystandard — Adults — tumour localisation
rulerule-contrast-reaction-premed — Prior contrast reaction and elective premedication; checked by Nurse before the scan
rulerule-metformin — Metformin and iodinated contrast; checked by Radiographer at the scanner
rulerule-paeds-dose — Child-sized technique and contrast dose; checked by Radiographer at the scanner
rulerule-pregnancy-ionising — Pregnancy status before an ionising exposure; checked by Radiographer at the scanner
rulerule-renal-iodinated — Kidney function and intravenous iodinated contrast; checked by Radiographer at the scanner
rulerule-iv-access — Intravenous access adequate for the planned injection; checked by Radiographer at the scanner

Decision support only. Local protocol takes precedence.

Handled at the scanner(4)nothing for you to do

Settled and owned downstream. Each returns to a radiologist only on the stated trigger.

Metformin and iodinated contrast
Confirm whether the patient takes metformin or a metformin-containing combination, and if so whether ACR Category II applies (eGFR below 30, known or suspected AKI, or an arterial catheter study likely to cause renal embolisation). If Category I — that is, no AKI and eGFR at or above 30 — no action of any kind is needed.
Radiographer at the scannerAt the scanner
Flags back if: The patient takes metformin AND meets ACR Category II — eGFR below 30 mL/min/1.73 m2, known or suspected acute kidney injury, or an arterial catheter procedure with likely renal arterial embolisation. Metformin plus a normal or mildly reduced eGFR is explicitly NOT a flag-back: there is no need to stop metformin before or after intravenous iodinated contrast in Category I patients, and no need to re-check creatinine afterwards.
Child-sized technique and contrast dose
Confirm that a size- or weight-based protocol is selected — child-sized kV and mAs against size-based diagnostic reference ranges — and that contrast volume is calculated by weight rather than taken from an adult default. Weight-based iodinated contrast volumes of roughly 1.5–2.0 mL/kg are widely used in paediatric CT.
Radiographer at the scannerAt the scanner
Flags back if: No paediatric or size-based protocol exists on the scanner for the requested examination, or the requested coverage or number of phases exceeds what the clinical question needs — for example a multiphase study where a single phase answers it, or whole-body coverage for a focal question.
Pregnancy status before an ionising exposure
Make the pregnancy enquiry immediately before the exposure and record the answer. In the UK this is a statutory operator duty discharged at the time of exposure under the employer’s written procedures required by IR(ME)R 2017 — it is not something the vetting radiologist can perform or pre-empt, and a request is complete without it.
Radiographer at the scannerAt the scanner
Flags back if: The patient states that she is, or may be, pregnant AND the uterus is in or near the primary beam. The exposure is then paused for re-justification by the IR(ME)R practitioner before it proceeds.
Intravenous access adequate for the planned injection
Site and test a cannula that supports the protocol flow rate, preferring an antecubital or large forearm vein, and observe the injection for extravasation. A 20-gauge or larger cannula is preferred for flow rates of 3 mL/s or more.
Radiographer at the scannerAt the scanner
Flags back if: No cannula can be sited that supports the protocol flow rate — for example only a 22-gauge hand or foot cannula for a CT angiogram needing 4–5 mL/s; or the only available access is a central line or port that is not labelled power-injectable; or an extravasation occurs.

Worth asking the referrer (1)

None of these hold the request up. They sharpen the protocol or the plan that follows.

Have plasma free or urinary fractionated metanephrines been measured, and what were they?
Imaging localises a biochemically established tumour. Scanning first inverts the pathway and generates incidental adrenal nodules that then need explaining.

Pathways

Big forks are separate pathways; the first whose conditions match is the one used.

Adults — tumour localisation

Matches your inputsDefault

Role	Study & protocol	Why this answers the question
First line	CT Abdomen and Pelvis CT Abdomen and Pelvis — Portal Venous Phase usually appropriate	Coverage is the reason this is a whole abdomen and pelvis study rather than an adrenal one. Most of these tumours are adrenal, but a substantial minority arise in the organ of Zuckerkandl, the bladder wall or anywhere along the para-aortic sympathetic chain, and a protocol targeted at the adrenal beds will simply not include them. Contrast-enhanced imaging is what shows the characteristically avid, often heterogeneous and necrotic enhancement pattern, and modern CT resolves lesions down to a few millimetres. Non-ionic contrast can be given without routine alpha blockade.
Reasonable alternative	MRI Adrenal MRI Adrenal — chemical shift	Preferred where radiation must be limited — genetic syndrome surveillance in a young patient, pregnancy, repeated follow-up — and where metastatic disease is being tracked. The morphological sequences, not the chemical-shift component, do the work here: these lesions are typically markedly T2-bright and do not lose signal on opposed-phase imaging, which is the opposite of an adenoma.
Second line	CT Chest CT Chest — Contrast-Enhanced (Venous Phase)	Extends the search when abdominal and pelvic imaging is negative despite convincing biochemistry, and is the study for pulmonary metastatic disease in a malignant paraganglioma.

Functional imaging with a catecholamine-analogue or somatostatin-receptor tracer is the next step when cross-sectional imaging is negative or metastatic disease is suspected; those tracers are not represented in this vocabulary and must be requested separately.

Pitfalls

Imaging before biochemistry. The result is a hunt for an incidental adrenal nodule that has nothing to do with the symptoms.
Restricting coverage to the adrenals and missing an extra-adrenal paraganglioma, which is the single commonest localisation failure.
Applying adenoma washout thresholds to these lesions and calling a phaeochromocytoma benign.
Withholding contrast on the historical belief that it provokes a crisis, and producing an unenhanced study that cannot show the enhancement pattern.
Forgetting that these tumours are frequently cystic or haemorrhagic and can be mistaken for a complex cyst or a haematoma.

Priors — what to pull first

A previous scan showing an adrenal nodule with high unenhanced attenuation and marked enhancement, previously dismissed as indeterminate, is often the lesion.
In a known predisposition syndrome, retrieve the surveillance protocol — the sites at risk differ by genotype and dictate coverage.

What makes a good request

The Endocrine Society guideline sequences the work-up as biochemical testing first, imaging second, and recommends CT of the abdomen and pelvis as the initial locating study, with MRI preferred where metastatic disease is present or radiation must be limited.
Roughly one in six of these tumours is extra-adrenal, and paragangliomas occur anywhere from the skull base to the pelvic floor. Coverage limited to the adrenal beds is the commonest way to miss one.
Adrenal washout criteria do not apply. Phaeochromocytomas are almost never lipid-rich, frequently exceed 10 HU unenhanced, and can show washout values in the adenoma range — the thresholds were not derived in this population.
The old teaching that iodinated contrast provokes a hypertensive crisis derives from ionic agents. Studies of non-ionic contrast in patients not taking alpha blockade found no pressor crises, and specific blockade before contrast-enhanced CT is not required on that basis.

Scoring this once it is done

The classification and risk tools this question ends in.

Adrenal Washout Calculator (CT)Semiquantitative mIBG (Curie) Score Adrenal MRI Chemical Shift (Signal Intensity Index & Adrenal-to-Spleen Ratio)

How these studies are acquired

Contrast, phases and timing for every study on the pathways above.

CT Abdomen and Pelvis — Portal Venous Phase MRI Adrenal — chemical shift CT Chest — Contrast-Enhanced (Venous Phase)

Confirm locally

CT Abdomen and Pelvis — Portal Venous Phase: timings are typical — confirm against local protocol.
Timings, contrast volumes and rates above are typical published values. Your department's protocol, scanner and patient population decide the actual numbers.
Safety thresholds and premedication policy follow local policy where it differs from the cited guidance.

References

Implemented from the cited published sources. Educational and workflow support only; confirm against current guidelines and local policy before clinical use.