Resources/Protocols
Liver / abdomen
A constantly moving target where the battle is against breathing and bowel motion, and the diagnosis lives in the timing. Multi-phase contrast catches lesions leaking dye — arterial wash-in, portal peak, delayed fill-in — so a consistent breath-hold and precise phase timing decide the exam.
When this study is used
- Characterising a focal liver lesion — cyst, haemangioma, HCC or metastasis.
- Metastasis screening in known malignancy.
- Biliary obstruction assessment (with MRCP).
Patient & coil positioning
- Head-first supine, perfectly straight and centred; arms raised above the head to clear phase wrap over the liver edges.
- Torso phased-array coil centred at the xiphoid process for full liver, diaphragm and upper-abdomen coverage.
- Rehearse the breath-hold: 'breathe in, breathe out, hold' at gentle exhalation — exhalation gives a reproducible diaphragm position and standardises slice planning.
Localizer
Fast three-plane localizer in a single breath-hold. The coronal must show the whole liver from dome to the inferior tip of the right lobe, including both adrenals and the diaphragm.
Sequence planning
Each sequence below lists how the slice group is positioned — the reference line it follows, its coverage, and why it earns its place in the protocol. Plan against the localizer, not by eye.
Axial T2 fat-sat
AxialPlanning — Angle parallel to the dome of the liver, following the diaphragm's curve — not a flat axial block. Extend to include pancreas and kidneys.
Why — Fluid-content lesions (cysts, haemangiomas bright as 'light bulbs') versus solid lesions.
Axial DWI (b=50, 800) + ADC
AxialPlanning — Match the T2 coverage; free-breathing with several averages if breath-hold is unreliable.
Why — Restricted diffusion (bright DWI, dark ADC) as a hallmark of malignancy.
Axial T1 in/out-phase
AxialPlanning — Dual-echo in one breath-hold.
Why — Microscopic fat (adenoma, steatosis) or iron — the liver darkens out-of-phase.
Dynamic T1 fat-sat (multi-phase)
AxialPlanning — Same volume repeated across phases; time the arterial phase with a test bolus or fluoro-trigger.
Why — Arterial (~20–35 s) for hypervascular lesions, portal (~60–70 s) for hypovascular metastases, delayed (3–5 min) for haemangioma fill-in.
MRCP (thick + thin slab)
Coronal obliquePlanning — Heavily T2-weighted slab centred on the common bile duct, from intrahepatic ducts to the pancreatic head; MIP reconstruction.
Why — Non-contrast map of the biliary tree — stones, strictures.
Representative parameters
Ranges, not commandments — field strength, coil and vendor move the numbers. What must not move is understanding why each sits where it does.
| Sequence | Breathing | Notes |
|---|---|---|
| T2 fat-sat | Breath-hold or triggered | Dome-parallel; lesion signal |
| DWI (b=50, 800) | Free-breathing, NEX 4–8 | Malignancy hallmark |
| T1 in/out-phase | Single breath-hold | Fat/iron detection |
| Dynamic T1 FS | Breath-hold per phase | Arterial 20–35 s, portal 60–70 s, delayed 3–5 min |
| MRCP | Respiratory-triggered | Thick slab + 3D thin slab, MIP |
Artifacts & how to fix them
| Artifact | Typical cause | Mitigation |
|---|---|---|
| Breathing motion | Inconsistent breath-holds | Rehearse; respiratory triggering; parallel imaging |
| Chemical shift (liver–kidney) | Fat–water mismatch at interfaces | Raise bandwidth; spectral fat-sat; swap phase |
| Poor fat-sat over the liver | B0 inhomogeneity, bowel gas | Re-shim on the right lobe; Dixon; STIR for non-contrast |
| Venous contamination (dynamic) | Arterial phase mistimed late | Test bolus / fluoro-trigger for exact timing |
What am I looking at?
You are not reporting the study, but recognising pathology helps you keep it in the field of view and know when to add a sequence or contrast. How the common findings read on the console:
| Finding | Sequence to check | How it reads |
|---|---|---|
| HCC | Dynamic T1 (arterial + delayed) | Arterial enhancement then wash-out — darker than liver on delayed |
| Haemangioma | T2 FS + delayed T1 | Very bright 'light bulb' on T2; peripheral nodular delayed fill-in |
| Metastasis | DWI + portal T1 | Restricts on DWI; hypovascular (dark) on portal phase |
| Fatty liver | T1 in/out-phase | Liver darkens on the out-of-phase image |
Review checklist
- Whole liver covered dome to inferior tip on every phase.
- Arterial phase caught at true wash-in, not late.
- In/out-phase acquired at the same level for comparison.
- MRCP MIP shows the biliary tree continuously (if acquired).
Mistakes that cost repeats
- Inconsistent breath-holds smearing the dynamic series.
- Arterial phase timed late, so hypervascular lesions are missed.
- Flat axial block instead of dome-parallel, clipping the liver top.
- Fat-sat shimmed on the whole abdomen rather than the right lobe.
Common questions
- Why hold the breath at exhalation for liver MRI?
- Exhalation puts the diaphragm in a consistent, reproducible position between breath-holds. That standardises slice planning and keeps the liver in the same place across the dynamic phases, which is essential for comparing enhancement.
- Why is contrast timing so critical in the liver?
- Lesions are characterised by how they enhance over time. HCC lights up in the arterial phase and washes out later; metastases are best seen in the portal phase; haemangiomas fill in on delayed images. Miss the timing and you miss the diagnosis.
- What does the in/out-phase sequence show?
- It detects microscopic fat or iron within tissue. On the out-of-phase image, tissue containing both fat and water loses signal — so a fatty liver or a fat-containing adenoma visibly darkens compared with the in-phase image.
Try it in ScanFlo: Run a dynamic series and step through the arterial, portal and delayed phases on the same slice. Watch a lesion enhance and then wash out — reading that time-course, not a single image, is how liver lesions are told apart.