CT Chest — Bronchial Artery CTA (pre-embolisation)

Thoracic inlet to below the costophrenic angles as a minimum, extended to include the aortic arch and the upper abdomen so that the coeliac axis, the inferior phrenic arteries and the subclavian and internal mammary origins are covered — the non-bronchial systemic feeders live outside a standard chest field of view, and a study that omits them answers only half the question.

Typical, not policy

Timings, volumes and delays here are representative values drawn from published guidance. Scanner generation, injector, cardiac output and local preference all move them. Confirm against your department's own protocol before you rely on a number.

When to use it

Massive or recurrent haemoptysis, as the road map immediately before bronchial artery embolisation.
Localising the bleeding side and lobe where bronchoscopy is non-diagnostic or unavailable, and simultaneously showing the underlying cause — bronchiectasis, aspergilloma, tuberculosis, malignancy.
Identifying an anomalous or ectopic bronchial artery origin, and any non-bronchial systemic supply, before the interventional radiologist takes the patient to the angiography suite.
Excluding a pulmonary arterial source such as a Rasmussen aneurysm or a pulmonary artery pseudoaneurysm, which is embolised by a different route and would be missed by an operator who assumed bronchial supply.

Technique

Timing is the whole protocol: acquisition triggers in the descending thoracic aorta and the scan must be arterial, because a venous-timed chest CT shows enhancing mediastinal veins and no bronchial arteries at all.
A high injection rate and a high iodine concentration are what make a 1-2 mm vessel visible; this cannot be achieved through a small peripheral cannula.
Extending the caudal coverage to include the coeliac axis and inferior phrenic arteries is not optional in a chronic inflammatory lung — inferior phrenic and intercostal feeders are common and are the usual reason embolisation fails.
Oblique maximum intensity projections along the descending aorta are how the bronchial artery origins are actually found; axial review alone will miss them.
A dedicated spinal artery search is worthwhile: a bronchial artery giving rise to an anterior spinal branch changes whether that vessel can be embolised at all.

Where it goes wrong

A venous-phase or routine staging chest CT will not show the bronchial arteries. Requesting "CT chest with contrast" for haemoptysis and then sending the patient for embolisation on that study is the commonest protocol error here.
Restricting coverage to a standard chest field of view and missing non-bronchial systemic feeders from the internal mammary, inferior phrenic, intercostal, subclavian and axillary arteries — recurrent bleeding after embolisation is most often from a feeder that was never imaged.
Failing to identify an anterior spinal artery arising from a bronchial artery, which is the origin of the spinal cord infarction risk that embolisation carries.
Assuming a bronchial source. Pulmonary arterial bleeding is a minority but it is a different procedure, and it is only distinguished by looking for it.
Delaying the scan to optimise renal safety in a patient who is exsanguinating into their airway. In massive haemoptysis the airway is the immediate threat and the renal check belongs downstream, not ahead of the scan.
Motion from coughing, which is near-universal in this population and is mitigated by the fastest available acquisition rather than by repeated breath-hold coaching.

Clinical questions that reach this study

Suspected pancreatic mass or painless obstructive jaundice Suspected cholangiocarcinoma Colorectal cancer — staging Incidental pulmonary nodule — characterisation and follow-up Known or suspected lung cancer — staging Suspected pneumonia and non-resolving consolidation Suspected empyema or complicated parapneumonic effusion Undiagnosed unilateral pleural effusion Suspected interstitial lung disease Suspected bronchiectasis Haemoptysis Suspected pneumothorax Suspected superior vena cava obstruction Staging or completion CT in a known solid tumour Liver assessment in a hypervascular primary Response assessment on systemic therapy Suspected or newly diagnosed lymphoma Metastatic disease with no identified primary Head and neck cancer — staging and post-treatment surveillance Indeterminate renal mass or suspected renal cell carcinoma Suspected phaeochromocytoma or paraganglioma Bladder cancer — pretreatment staging Acute scrotum and scrotal mass Suspected ovarian cancer or indeterminate adnexal mass

Contrast

Iodinated, intravenous

Typically 80-100 mL of high-concentration non-ionic iodinated contrast at 4-5 mL/s through a cannula of at least 18-20G, with a saline chaser. Bolus-tracked with the monitoring ROI in the descending thoracic aorta at around 100-150 HU and a short post-trigger delay of roughly 4-6 seconds — short deliberately, because the bronchial arteries fill with the aorta and a longer delay lets the pulmonary veins and mediastinal veins opacify, which is what makes a 1-2 mm systemic feeder impossible to follow. Where tracking is unavailable, a fixed delay of about 15-20 seconds is the fallback and is less reliable.

Acquisition

Breathing: Single inspiratory breath-hold where possible; in a patient who is actively bleeding, a fast free-breathing acquisition is preferable to a delayed one.
Reconstruction: Thin sub-millimetre axial reconstructions in a soft-tissue kernel with sagittal and coronal reformats and maximum intensity projections in oblique planes along the descending aorta; a lung kernel series in parallel to show the parenchymal source of bleeding.
Preparation: Full inspiratory breath-hold, practised before the acquisition. Arms above the head; arms down doubles streak artefact through the upper thorax.

Phases

Each phase is authored once and shared across every protocol that uses it, so the physiology below is the same wherever you meet it.

CT angiography, bolus-trackedNo fixed delay. A monitoring ROI is placed in the target vessel (commonly the aorta) and acquisition triggers at a set attenuation rise — a ~100 HU threshold is widely used — followed by a short diagnostic delay of a few seconds for table movement and breath-hold instruction. Confirm locally.
This is not a separate physiological phase so much as a technique for hitting one reliably. The transferable principle is that a fixed delay assumes an average circulation, and the patients who most need vascular imaging — the shocked, the failing, the arrhythmic, the aneurysmal — are precisely those whose circulation time is furthest from average. Tracking the bolus in the target vessel replaces that assumption with a measurement, so peak arterial opacification is achieved in the individual patient. The trade-off is that the technique commits the scan to whatever the monitoring ROI sees: a badly placed ROI, a mistimed breath-hold or a threshold reached by a contralateral vein produces a systematically mistimed study rather than a slightly degraded one.

Safety checks this protocol carries

Derived from the contrast agent and phases above, not authored here — which is why they cannot drift apart from what the protocol actually does.

Prior contrast reaction and elective premedication· nurse pre scan
Intravenous access adequate for the planned injection· radiographer at scan
Metformin and iodinated contrast· radiographer at scan
Child-sized technique and contrast dose· radiographer at scan
Pregnancy status before an ionising exposure· radiographer at scan
Kidney function and intravenous iodinated contrast· radiographer at scan

References

ACR Appropriateness Criteria — Hemoptysis
CIRSE Standards of Practice on Bronchial Artery Embolisation. Cardiovascular and Interventional Radiology.
Multidetector CT angiography of bronchial and non-bronchial systemic arteries in the evaluation of haemoptysis. RadioGraphics.