Cine MRI is an MRI that is a loop, not a still: many frames of the same plane, timed to a repeating motion (a heartbeat, CSF, a joint). It is physiology, not a photograph of anatomy. It is not a standard uptake value. It is not a perfusion map. It is not a Hounsfield unit.
If you meant PET SUV → standard uptake values. If you meant the SUVbw calculator → SUV calculator. If you meant tissue blood-flow → tissue perfusion. If you meant AHA 17-segment wall-motion language → cardiac segments. If you meant drawing chambers → heart segmentation. If you meant Tesla / spatial-temporal-contrast → resolution of MRI (a later leftover; pointed, not rewritten).
706 left this URL on purpose. Cardiac / cine MRI ≠ SUV. PYCAD builds custom web DICOM viewers and imaging models. It does not ship a cine workstation or a cardiac-MRI product.
A loop, not a camcorder
A clinical cine is almost never “hit record for ten seconds.” The heart moves faster than a fully sampled k-space line. The scanner takes one (or a few) k-space segments per heartbeat, at a known phase of the cycle, and builds each frame across many beats. ECG leads give the timing. That is gating.
- Retrospective gating. Acquire through the cycle, bin by the ECG after. You can reconstruct more phases. Arrhythmia and a changing R–R mess the bins.
- Prospective gating. Trigger on the R-wave and acquire a planned window. Cleaner if the rate is steady; you can miss late diastole.
- Breath-hold. Most cardiac cine is a short hold per slice. Free-breathing / real-time cine exists; spatial or temporal resolution usually pays.
The workhorse contrast for cardiac cine is balanced steady-state free precession (bSSFP; vendor names include TrueFISP / FIESTA / b-FFE). Blood is bright, myocardium is darker. That blood–muscle edge is why ejection fraction and wall motion are readable. SSFP is not a flow-quant sequence. Phase-contrast cine is the one that encodes velocity; do not call an SSFP jet “a flow measurement.”
The knobs that actually change the movie
| Knob | What it is | What you trade |
|---|---|---|
| Temporal resolution | Time between frames in the reconstructed loop (how fine the cycle is sampled) | Finer frames catch a valve leaflet. They cost SNR or spatial resolution or breath-hold length |
| Spatial resolution | Pixel / slice thickness | Needed for a thin wall or a small VSD. Costs time or SNR |
| TR / TE | How often you excite, when you listen | Short TR/TE is how bSSFP stays balanced and motion-tolerant. Wrong pair = banding, not “more cinema” |
| Views per segment | How much k-space you grab per beat for one frame | More views → fewer beats → shorter hold, worse temporal resolution |
| Flip / banding | bSSFP is sensitive to off-resonance | A bright blood pool with black bands at 3 T is a field/shim problem, not a disease |
EF wants enough phases to see end-diastole and end-systole. A valve leaflet wants temporal resolution more than a pretty still. A tiny mass on a leaflet wants spatial resolution and may not need a 40-phase loop. The leftover resolution of MRI URL is Tesla / spatial-temporal-contrast as a glossary; this page is the cine trade.
What people use the loop for
- Ventricular volumes and EF. Trace (or a model traces) the cavity on short-axis cine through the cycle. Stroke volume and EF come from those volumes. That is why cine is the reference for function in a lot of cardiac MRI protocols. The AHA 17-segment names for where the wall fails live on cardiac segments. Drawing the chamber as a mask is heart segmentation.
- Wall motion. Akinesis / hypokinesis / dyskinesis after infarct. The loop shows it; late gadolinium enhancement (a different series) says whether that wall is scar.
- Valves, qualitatively. A dark or bright jet on SSFP is a clue. Quantifying regurgitant volume is usually phase-contrast plus volumetry, not “eyeball the SSFP jet.”
- Congenital anatomy in motion. Connections and streaming you cannot hold in one still. Planning still wants the static anatomy series too.
- CSF. Phase-contrast cine at the aqueduct or foramen magnum (Chiari, a suspected blockage). Different encoding; same “loop” idea.
- Joints. Kinematic cine of a knee or TMJ. Niche, real, not a cardiac protocol with the name filed off.
Perfusion imaging (first-pass gadolinium, arterial spin label) is a flow through tissue map. That job sits on tissue perfusion. A PET SUV is activity / dose / weight — standard uptake values and the calculator. Do not 301 this URL into either.
AI, without the 0.98
The slow step is tracing every short-axis frame. Models that segment LV / RV / myocardium on cine and emit EF / volumes / mass exist in papers and in some vendor tools. They fail on the cases you care about: congenital, metal, a truncated apex, a right ventricle that is not the training prior. A published AUC on one challenge is not a clinic. The radiologist still signs.
CineMA and similar foundation-model write-ups are one research line. They are not a PYCAD cine product and not a reason to keep a Nature-link costume in this article.
What this page is not
- Not a patient prep FAQ (gown, metal, hold still). That is the site protocol, not an explainer.
- Not a buyer’s guide for a cine workstation.
- Not 4D CT (a different leftover / cluster job: a moving CT target).
- Not a PYCAD cardiac-AI SKU.
The file is still DICOM. A web viewer that can play a cine loop is a viewer feature, not a new modality.