Resources/Protocols
Pituitary / sella
Fine-detail imaging of a millimetre-scale gland. The target is often a microadenoma, and the trick is timing — the normal gland enhances instantly, the adenoma lags — so a dynamic contrast run is the money sequence.
When this study is used
- Hormonal imbalance (prolactinoma, acromegaly, Cushing's) — microadenoma hunt.
- Visual-field defect from a macroadenoma compressing the optic chiasm.
- Suspected sellar or parasellar mass.
Patient & coil positioning
- Head-first supine in a high-channel head coil, straight and snug; the sub-millimetre sequences make 2 mm of motion diagnostic-ruining.
- Centre on the glabella at the magnet isocentre for best field homogeneity.
- Firm padding and a forehead strap for sensory feedback.
Localizer
Three-plane localizer confirming a straight, centred head. The dedicated sequences focus a small FOV on the sella.
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.
Sagittal T1 (thin)
SagittalPlanning — Small FOV centred on the sella; sphenoid sinus to dorsum sellae.
Why — Midline anatomy — stalk, chiasm, gland height.
Coronal T1 & T2 (thin)
CoronalPlanning — Perpendicular to the sellar floor, aligned to the pituitary stalk. ≤3 mm slices, high matrix.
Why — Adenomas often read hypointense on T1 against the gland.
Dynamic coronal T1
CoronalPlanning — Same slice repeated every 20–30 s, starting with the injection.
Why — The wash-in test — the normal gland enhances first, a microadenoma stays dark as a filling defect before catching up.
Coronal T1 fat-sat post-contrast
CoronalPlanning — After the dynamic run.
Why — Delayed enhancement, cavernous-sinus and parasellar extension.
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 | Slice | Notes |
|---|---|---|
| Coronal T1/T2 | ≤3 mm | High matrix, small FOV |
| Dynamic T1 | ≤3 mm | Same slice every 20–30 s |
| Post-contrast T1 FS | ≤3 mm | Delayed, parasellar extent |
Artifacts & how to fix them
| Artifact | Typical cause | Mitigation |
|---|---|---|
| Motion blur | Long thin-slice acquisition | Firm immobilisation; efficient sequencing |
| Susceptibility from sinus | Air–bone at the sphenoid | Spin echo; short TE; careful shim |
| Missed microadenoma | Static post-contrast only | Always run the dynamic phase for wash-in 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 |
|---|---|---|
| Microadenoma | Dynamic coronal T1 | Small dark focus in the brightly enhancing gland during early phase |
| Macroadenoma | Sagittal/coronal T1+C | Sellar mass with 'snowman' shape indenting the chiasm |
| Stalk deviation | Coronal T1 | Infundibulum pushed away from the lesion |
Review checklist
- Small FOV centred tightly on the sella.
- Coronals aligned to the stalk, ≤3 mm, high matrix.
- Dynamic phase acquired for wash-in timing.
- Parasellar and cavernous-sinus extension assessed post-contrast.
Mistakes that cost repeats
- Relying on a single post-contrast series and missing a microadenoma.
- FOV too large, losing the resolution the gland needs.
- Motion over the long high-resolution acquisition.
- Slices not aligned to the stalk, foreshortening the gland.
Common questions
- Why is dynamic contrast used for pituitary imaging?
- A microadenoma usually enhances more slowly than normal gland tissue. Imaging repeatedly during contrast arrival captures that difference — the adenoma appears as a dark filling defect before it too enhances — which a single static post-contrast series can miss.
- How thin should pituitary slices be?
- 3 mm or less with a small field of view and a high matrix. The gland is only millimetres across, so resolution matters more than coverage here.
- Why align the coronals to the pituitary stalk?
- The stalk (infundibulum) is the anatomical anchor of the sella. Angling coronals to it gives true cross-sections of the gland and shows stalk deviation, an important sign of a small lesion.
Try it in ScanFlo: Run a dynamic coronal T1 and step through the phases on one slice. Watch the normal gland brighten first while a filling defect lags — that timing difference, not any single image, is how a microadenoma is caught.