Cine bSSFP
| Artefact | Appearance | Cause | Fix |
|---|---|---|---|
| Off-resonance banding | Dark bands across the image, worst at the edges of the field and near lung, sternum and devices | B0 inhomogeneity; bSSFP signal nulls where the off-resonance phase accumulated per TR reaches π | Re-shim over the heart; adjust centre frequency; shorten TR; spoiled GRE cine (worse blood-myocardium contrast, no banding) |
| Flow ghosting | Copies of bright blood displaced along the phase-encode direction | Pulsatile flow; incomplete breath-hold | Swap phase-encode direction; saturation bands; repeat the breath-hold |
| Respiratory blurring | Blurred endocardial border, doubled diaphragm | Breathing during the segmented acquisition | Shorter breath-hold (fewer phases, higher acceleration); real-time cine; respiratory-gated free-breathing cine |
| Arrhythmia | Blurred or stepped edges, dropped frames, blocky appearance | Irregular R-R intervals corrupt the segmented k-space | Arrhythmia rejection window; prospective triggering; real-time cine |
| Mis-triggering | Ghosting, wrong phase order, very short apparent R-R | ECG trace degraded by the magnetohydrodynamic effect or poor electrode contact; T-wave triggering | Re-position electrodes; vectorcardiographic gating; pulse oximetry gating as a last resort |
| Wraparound (aliasing) | Anatomy from outside the field of view folded onto the image | Field of view smaller than the object in the phase-encode direction | Increase FOV; phase oversampling; saturation band over the arms |
| Parallel imaging | Fold-over or a band of noise in the centre of the image | Acceleration factor too high for the coil geometry (g-factor); wrong calibration | Lower acceleration; re-acquire calibration; change phase-encode direction |
| Metal susceptibility | Signal void with distortion, sometimes with bright pile-up at the edge | Sternal wires, valve prostheses, clips, devices | Spoiled GRE cine; shorter TE; the void is smaller at 1.5T than 3T |
Late gadolinium enhancement
| Artefact | Appearance | Cause | Fix |
|---|---|---|---|
| Wrong inversion time | Myocardium grey rather than black (TI too short: signal may invert and mimic enhancement; TI too long: reduced scar contrast) | TI not matched to the current myocardial T1, which shortens with time after contrast | Repeat the TI scout; phase-sensitive inversion recovery (PSIR), which is insensitive to TI error |
| Bright blood masking subendocardium | Thin subendocardial enhancement invisible against the blood pool | Blood and scar both bright on standard LGE | Dark-blood LGE variants; longer TI; compare with cine wall motion |
| Motion ghosting | Copies of enhancing structures along phase encode; blurred scar | Breathing or arrhythmia during the segmented acquisition | Single-shot LGE with motion correction and averaging (free-breathing); repeat with a shorter breath-hold |
| Gibbs ringing | Thin bright or dark line parallel to a sharp edge, most often at the blood-myocardium interface | Truncation of k-space at the acquisition matrix | Higher matrix; check the line moves with the phase-encode direction |
| Metal susceptibility | Signal void and distortion near the implant; inversion fails locally, so myocardium next to a device appears bright | Local field distortion from the device, wires or valve | Wideband inversion pulse for ICDs; spoiled GRE readout; shorter TE |
| Wraparound | Anatomy folded onto the heart | Small FOV | Increase FOV or phase oversampling |
First-pass perfusion
| Artefact | Appearance | Cause | Fix |
|---|---|---|---|
| Dark rim artefact | Thin dark subendocardial line, 1 to 2 pixels, appearing as the bolus arrives in the LV cavity and fading over a few frames | Gibbs truncation and cardiac motion at the sharp blood-myocardium boundary during peak contrast | Higher in-plane resolution; see the comparison below; a true defect persists and follows a coronary territory |
| Respiratory motion | Slices drift through the stack, mis-registered frames | Breathing during the 40 to 60 heartbeat acquisition | Motion-corrected reconstruction; coach a breath-hold through peak enhancement; free-breathing protocols with registration |
| Parallel imaging noise | Central band of noise or fold-over in each frame | High acceleration in a low-SNR sequence | Lower acceleration; alternative reconstruction (kt or compressed sensing) |
| Off-resonance | Dark bands through the myocardium in every frame (bSSFP readout) | B0 inhomogeneity | Shim; spoiled GRE readout, which is standard at 3T |
| Arrhythmia | Missed or repeated frames; a slice acquired at a different cardiac phase | Irregular R-R with a fixed slice schedule | Read the frame timing; accept if the defect persists across frames; repeat if in doubt |
T1, T2 and T2* mapping
| Artefact | Sequence | Appearance | Cause and fix |
|---|---|---|---|
| Mis-registration | T1, T2 | Bright or dark rim at the endocardium or epicardium on the map; poor fit quality | Breathing or motion between the source images. Motion-corrected fitting; repeat with a better breath-hold; read the fit error map |
| Heart-rate dependence | MOLLI T1 | T1 underestimated at high heart rates, and shifted by ectopics | Incomplete recovery between inversions. Heart-rate-adapted schemes (5(3)3), ShMOLLI or SASHA; report the scheme used |
| Off-resonance | bSSFP-based T1 and T2 | Regional T1 or T2 error, usually inferolateral or near lung | B0 inhomogeneity through the bSSFP readout. Shim; check the frequency; exclude the segment |
| Partial volume | All | Elevated values at the blood-myocardium border and in thin walls | Contours too close to the border. Erode the ROI; report septal values |
| Susceptibility | T2* | Falsely short T2* near the inferior wall, posterior vein, lung and RV insertion | Local field gradients. Measure the mid-septum only; truncate the late echoes in heavy iron loading; 1.5T |
| Fat-water swap | Dixon | Fat and water images exchanged, regionally or whole-slice | Phase unwrapping failure with poor shim. Re-shim and repeat; three-point Dixon |
Dark rim artefact versus true subendocardial defect or LGE
| Feature | Dark rim artefact | True finding |
|---|---|---|
| Distribution | Circumferential or at the phase-encode edges, all territories | Follows a coronary territory |
| Timing (perfusion) | Appears with cavity enhancement, gone within a few frames | Persists through and after peak myocardial enhancement |
| Thickness | 1 to 2 pixels, uniform | Wider, transmural extent varies |
| Phase-encode direction | Changes with it | Does not |
| Wall motion | Normal | Often abnormal in the same segment |
| LGE | None in the segment | Matching subendocardial LGE in infarction; none in ischaemia without infarction |
- Ferreira PF, Gatehouse PD, Mohiaddin RH, Firmin DN. Cardiovascular magnetic resonance artefacts. J Cardiovasc Magn Reson 2013;15(1):41. doi:10.1186/1532-429X-15-41
- Di Bella EVR, Parker DL, Sinusas AJ. On the dark rim artifact in dynamic contrast-enhanced MRI myocardial perfusion studies. Magn Reson Med 2005;54(5):1295-1299. doi:10.1002/mrm.20666
- Kramer CM, Barkhausen J, Bucciarelli-Ducci C, Flamm SD, Kim RJ, Nagel E. Standardized cardiovascular magnetic resonance imaging (CMR) protocols: 2020 update. J Cardiovasc Magn Reson 2020;22(1):17. doi:10.1186/s12968-020-00607-1
- Messroghli DR, Moon JC, Ferreira VM, et al. Clinical recommendations for cardiovascular magnetic resonance mapping of T1, T2, T2* and extracellular volume: a consensus statement by SCMR endorsed by EACVI. J Cardiovasc Magn Reson 2017;19(1):75. doi:10.1186/s12968-017-0389-8