Inflow Inversion-Recovery bSSFP Angiography (b-TFE / B-TRANCE, NATIVE TrueFISP, Inhance Inflow IR, Time-SLIP) — Inversion Geometry, TI, Triggering, Respiratory Strategy, Acceleration and Renal Evidence
Linked parent page: Balanced Steady-State Free Precession (bSSFP) Sequence — Physics, Contrast, Off-Resonance Banding, Variants, Vendor Nomenclature (TrueFISP, FIESTA, Balanced FFE / b-TFE) and Clinical Use
Inflow Inversion-Recovery bSSFP Angiography — Philips b-TFE / B-TRANCE and Equivalents (Time-SLIP, NATIVE TrueFISP, Inhance Inflow IR): Inversion Geometry, TI, Triggering, Respiratory Strategy, Acceleration and Renal Evidence
MRIninja Knowledge Base | Sequence/Technique Deep Dive Builds on: Triggered Non-Contrast-Enhanced MRA (Section 6) · bSSFP Sequence · Stationary Tissue vs. Flowing Fluid Version 1.0 — October 2026
1. Introduction and Scope
The Triggered Non-Contrast-Enhanced MRA page places inflow inversion-recovery (inflow-IR) bSSFP in the taxonomy of non-contrast methods and summarises it in a single section; the bSSFP Sequence page develops the physics of the readout (T2/T1 contrast, transient phase, banding). This page assumes both as known and develops what neither covers: how the inversion is built, how the inversion time is chosen, how triggering and breathing are handled, how the acquisition is accelerated, how the vendor implementations differ, and what the renal evidence actually shows. It is organised around the Philips implementation (readout named balanced FFE or b-TFE; angiographic product name B-TRANCE) because that is the platform for which the user-facing names are least transparent, with the other vendors' equivalents covered for comparison.
Names, stated precisely. In the sources verified for this page, a Philips group describes b-TRANCE as "a VCG-triggered balanced SSFP sequence with a slice-selective inversion pulse" [9]; the readout is called "balanced turbo field echo (B-TFE)" in a Philips-affiliated renal study [10] and "balanced FFE (bFFE)" in a Philips-affiliated portal-vein study [8]. Edelman and Koktzoglou list B-TRANCE as the Philips counterpart of Siemens NATIVE TrueFISP, GE Inhance Inflow IR and Canon Time-SLIP [13]. "TRANCE" is not one sequence: in the same Philips-affiliated portal-vein abstract, "3D TRANCE" is a turbo spin-echo sequence acquired without ECG triggering, compared against a 3D balanced FFE readout [8], whereas in the lower-limb literature TRANCE is a peripheral-pulse- or ECG-triggered 3D TSE subtraction technique [7]. The suffix describes the strategy (triggered, non-contrast angiography); the readout (TSE or balanced FFE) differs by application, and the "B-" prefix marks the balanced readout.
Information status. Numerical parameters are quoted only from sources that report them, with platform and field strength, and are examples of reported practice rather than recommended settings. Several primary sources were available only as abstracts, which is stated in the bibliography. Two sources could not be read at all (Section 10).
2. The Inversion Pulse — Two Geometries That Share One Idea
2.1 The Shared Principle
In every implementation, an inversion pulse is used to make the stationary background in the imaging region nearly null at the moment of readout, while blood that has entered the region after the inversion arrives with magnetisation that has not been inverted (or has been restored), and therefore appears bright on the bSSFP readout [13,14,15]. The contrast is thus inflow-dependent and non-subtractive: a single acquisition, with no systolic/diastolic or tag/control pair [13].
2.2 Region (Slab-/Slice-Selective) Inversion
Siemens describes NATIVE TrueFISP as an inversion pulse applied to the region of interest, "fresh non-inverted blood flowing into the inverted slab appearing bright"; the upper limit of the inversion band should match the upper limit of the FOV [14]. Edelman and Koktzoglou describe a thick axial inversion band that suppresses stationary and venous signal, with chemical fat suppression and a wait of up to 1400 ms for inflow [13]. The Philips description of B-TRANCE as bSSFP with a "slice-selective inversion pulse" [9] is consistent with this geometry; the retrieved sources do not specify the band orientation or thickness on the Philips console, and those fields are not described here.
2.3 Time-SLIP: Non-Selective Plus Selective Inversion
Time-SLIP (Canon / Toshiba) is described as combining a non-selective 180° pulse, which inverts the imaging region and the surrounding tissue, with a selective 180° pulse applied to an upstream region: spins in the upstream region receive two 180° pulses and are restored toward positive longitudinal magnetisation, whereas the background outside the selective region stays inverted; at the chosen inversion time the stationary tissue approaches its null point while the restored upstream blood has flowed into the imaging volume [15]. The same source notes that some methods acquire tag-on and tag-off images and subtract them to improve background suppression [15]. Time-SLIP angiography of the renal arteries has been evaluated in a prospective study with a 3D flow-in bSSFP readout at 1.5 T [2] and in an international multicentre trial [1]. The relationship between the Time-SLIP geometry and the Philips and Siemens region-inversion implementations is therefore one of how the inflowing blood is tagged, not of the readout.
| Item | Region inversion (NATIVE TrueFISP; Inhance Inflow IR; B-TRANCE per [9]) | Time-SLIP |
|---|---|---|
| Inversion pulses | Inversion of the region/slab of interest [13,14] | Non-selective plus selective 180° pulse [15] |
| Blood signal source | Fresh non-inverted blood entering the inverted slab [14] | Upstream blood restored by two inversions and flowing in [15] |
| Background | Inverted, nulled near the readout [13] | Inverted outside the selective region, nulled near the readout [15] |
| Readout | 3D bSSFP [13,14] | 3D bSSFP in the renal studies [1,2] |
2.4 How This Differs from Time-of-Flight (TOF) Inflow
Both families depend on inflow of blood that differs in magnetisation from the stationary tissue, but the mechanism that suppresses the background is different. In TOF, "stationary tissues in an imaged volume become magnetically saturated by multiple repetitive RF-pulses", and blood entering the slab is not saturated, so it "appears paradoxically bright compared to background tissue"; flip angles of 30°–60° are used to maximise this contrast, and enhancement is greatest when the vessel is perpendicular to the imaging plane, so TOF is "somewhat insensitive to in-plane flow" [17]. In inflow-IR bSSFP the background is not saturated but inverted and allowed to recover to its null point at the readout [13,14,15], and the readout itself is a bSSFP, whose native blood signal is high for reasons that have nothing to do with flow (T2/T1 contrast, see the bSSFP page).
| Feature | TOF | Inflow-IR bSSFP (b-TFE / B-TRANCE and equivalents) |
|---|---|---|
| Background suppression | Steady-state saturation by repeated RF [17] | Inversion and recovery to the null point at the chosen TI [13,14] |
| Readout | Spoiled gradient echo | Balanced SSFP (see the bSSFP page) |
| Timing parameter | No inversion time; slab thickness is limited by saturation of the inflowing blood [17] | Explicit TI, about 1000–1400 ms in the cited sources [14,15] |
| Cardiac triggering | Not part of the basic technique | Triggered, with an inversion per trigger when ECG is used [9,14] |
| Typical target | In-plane flow is a recognised limitation [17]; target vessels not stated on that page | Renal and abdominal arteries; "generally ineffective" for peripheral arteries [13] |
| Signal dependence on vessel orientation | Strong: in-plane flow saturates [17] | Not described as a limitation in the retrieved sources; dependent on the inflow direction relative to the inversion region [15] |
Reasoning, not a quoted statement: the practical consequence of the different suppression mechanism is that the key parameter of TOF is the relationship between TR, flip angle, slab thickness and blood velocity, whereas the key parameter of inflow-IR is the TI relative to the heart rate and the blood travel distance. A TR or flip-angle adjustment that improves a TOF angiogram has no equivalent effect on the background suppression of an inflow-IR scan, where the nulling is set by the TI.
3. Inversion Time, Triggering and the Cardiac Cycle
3.1 Choosing TI
TI sets the balance between two competing requirements: it must be long enough for fresh blood to travel into the imaging region and fill the vessel, and short enough that the inverted stationary tissue is still close to its null point at readout. Reported values are:
- Time-SLIP at 1.5 T: a typical TI "on the order of 1000–1200 ms", depending on anatomy, field strength, flow velocity, heart rate and tissue T1 [15];
- Siemens NATIVE TrueFISP: "long enough to always include an inflow episode (eg 1200 to 1400 ms)" when running without ECG; when 1400 ms does not fit in a single R–R interval, every second trigger is used while the trigger-pulse parameter stays at 1 [14];
- inflow times of up to 1400 ms in the general review [13].
Reasoning, not a quoted statement: a TI that is too short leaves the vessel only partly filled, which would shorten the visible vessel length (the shorter mean maximal visible length of 61.1 mm for non-enhanced SSFP versus 69.9 mm for contrast-enhanced MRA in one prospective study is consistent with, but not proof of, this effect [3]); a TI that is too long lets the background recover and reduces suppression. The Time-SLIP source states that the TI should be adapted to heart rate, flow velocity and anatomy [15], and a Philips-affiliated abstract on respiratory-triggered renal MRA reports that optimising flip angle and TI is what allows renal arteries to be visualised [11]; the specific values are not given in the retrieved text.
3.2 Triggering
Philips describes B-TRANCE as VCG-triggered [9]; Siemens recommends ECG triggering "highly", with a new inversion played out for each trigger, and notes that data can be acquired without ECG [14]. The reason for triggering is to fix the phase of the cardiac cycle at which inflow and readout take place, since inflow velocity and thus the filled vessel length vary within the cycle (general reasoning consistent with the pulsatility described on the triggered NCE-MRA page). Which cardiac phase the readout window is placed in on each platform is not stated in the retrieved sources and is not asserted here. Siemens states that the inversion time is maximised automatically and that the captured cycle can be checked on the Geometry-Inversion subcard [14].
4. The bSSFP Readout in This Setting
The behaviour of the readout follows the bSSFP page; the points specific to angiography are:
- Short TR and banding. The Philips-affiliated portal-vein study reports a 3D balanced FFE with TR 5.6–6.0 ms, TE 1.86 ms and a flip angle of 85° on a 1.5 T Achieva system [8]. These values lie inside the 3–6 ms range that Scheffler and Lehnhardt give for banding control at 1.5 T [16]. The banding trade-offs at 3 T are those of the bSSFP page.
- Fat. Fat is bright on bSSFP; Edelman and Koktzoglou describe chemical fat suppression in this family [13], and a 3T Inhance study describes the technique as "3D fat-suppressed inflow inversion recovery balanced SSFP" [5].
- Background suppression. A T2-preparation added to a respiratory-triggered, selective-inversion, balanced-SSFP renal protocol was reported to improve vessel-to-background contrast and image quality of the aorta and renal arteries in healthy volunteers (abstract) [11].
- Transmit hardware at 3 T. The Philips 3 T B-TRANCE work used a multi-transmit body coil with 16-channel anterior and 12-channel posterior receive coils [9].
The choice of readout is itself a variable: in healthy volunteers, a 3D TSE-based TRANCE gave higher SNR and CNR in every vessel and more portal-venous branches than a 3D balanced FFE with Time-SLIP (for example mean portal vein SNR 227 ± 118 versus 140 ± 59), with a mean image-quality score of 3.6 ± 0.5 versus 3.0 ± 0.8 [8]. This is an abstract in 25 volunteers and does not establish equivalence in patients; its relevance here is that a bSSFP readout is chosen for its speed and blood signal, not because it is superior in every territory. The Time-SLIP review source states that a TSE readout is less susceptible to susceptibility effects and is preferred in the lungs, where air–tissue interfaces make bSSFP problematic [15].
4.1 Banding in Inflow-IR Angiography
The mechanism and general mitigation of banding are developed on the bSSFP page (Section 5): the signal is periodic in the off-resonance frequency, with signal voids at ±1/(2·TR) from the centre frequency repeating every 1/TR [16]. This section covers only what is specific to the angiographic use.
Worked numbers from the reported parameters. The following is arithmetic from the band-spacing relationship, applied to TR values reported in the sources above, not a measurement from them:
| Reported TR | Source and setting | Band spacing (1/TR) | First band from centre (±1/(2·TR)) |
|---|---|---|---|
| 5.1 ms | GE inflow-IR bSSFP, 3 T (TR/TE/TI 5.1/2.5/1300 ms, ±125 kHz bandwidth, 54 slices of 2.0 mm) [12] | ≈ 196 Hz | ≈ ±98 Hz |
| 5.6–6.0 ms | Philips balanced FFE, 1.5 T, portal vein [8] | ≈ 167–179 Hz | ≈ ±83–89 Hz |
For scale, the water–fat chemical shift of about 3.5 ppm corresponds to roughly 224 Hz at 1.5 T and 447 Hz at 3 T (general MR physics, calculated from the proton Larmor frequency, not drawn from the cited sources). For TR values of 5–6 ms the fat–water separation therefore spans more than one band period at both field strengths (about 1.1–1.3 periods at 1.5 T and 2.3–2.7 periods at 3 T, by the same arithmetic), so fat and water cannot both sit away from a band; the SCMR consensus likewise states that at 3 T the increased sensitivity of bSSFP to off-resonance "tends to worsen dark banding and flow artifacts" [18].
Why it matters for an angiogram. Reasoning, not a quoted statement: the inversion nulls the stationary background, so bands in the background are largely invisible; the clinically relevant effect is a band falling across a vessel, where the lumen signal drops and may resemble a stenosis or occlusion. Large coverage in the abdomen, with bowel gas and the kidneys within the shim volume, increases the field variation that must be accommodated. Edelman and Koktzoglou note that bSSFP is more sensitive to off-resonance than fast spin-echo [13]. No study retrieved for this page quantifies how often banding produces a false-positive stenosis in inflow-IR renal angiography, and the renal accuracy studies in Section 7 do not report it as a separate error class.
A logical test for a suspected band artefact. Reasoning, not a published protocol: because band positions depend on the off-resonance map and on TR, a signal loss that moves or disappears when the centre frequency or TR is changed slightly is not anatomical, whereas a true stenosis stays at the same position. Mitigation options named in the sources are shimming over the vessel region, short TR, adjusting the centre frequency and, where applicable, phase-cycled acquisitions [16,18]; phase-cycled combination multiplies the scan time and its use in triggered angiography was not described in the retrieved sources. Philips-specific console controls for shim volume and frequency adjustment were not established in the retrieved sources and are not listed here.
Example images of banding were not embedded: illustrative figures found in the literature are subject to publisher copyright, and no verified b-TFE angiographic example with a reusable licence was identified. Site-owned, anonymised images are preferable.
5. Respiratory Strategy and Acceleration
Renal and abdominal arteries move with respiration, and inflow-IR scans are long enough that this matters: Philips-affiliated authors describe b-TRANCE as taking "long enough" that motion artefacts are a problem, with respiratory gating or navigation reducing motion but lengthening the scan [9]. Five approaches appear in the verified literature:
| Strategy | Implementation and reported detail | Source |
|---|---|---|
| Navigator / respiratory gating | 1D PACE navigator on Siemens NATIVE TrueFISP (alternative: respiratory cushion); respiratory gating "typically used" in the general review; irregular breathing degrades images; image quality significantly better with stable respiration in a 72-subject study (p < 0.01) | [13,14,4] |
| Regulated breathing | Breathing regulated with recorded voice instructions in a prospective 23-patient Time-SLIP study at 1.5 T | [2] |
| Respiratory triggering | Respiratory-triggered selective-inversion balanced SSFP in healthy volunteers (abstract) | [11] |
| Breath-hold with compressed sensing | b-TRANCE with Compressed SENSE at 3 T: acceleration factor 5 for breath-hold and 6 for free-breathing in the main comparisons, up to 16 in one volunteer, for which the breath-hold scan took 19 seconds; free-breathing b-TRANCE in about 30 seconds; a radiologist rated all scans diagnostic with consistent reproducibility (four volunteers; abstract) | [9] |
| Accelerated B-TFE (CS-SENSE) | 3.0 T Ingenia CX, 11 healthy volunteers, six protocols (SENSE 2; CS-SENSE 2, 4, 6, 8, 10): factors 2, 4 and 6 showed no significant difference from SENSE 2 in SNR, CNR or subjective score; CS-SENSE 6 took 75 s versus 243 s for SENSE 2; factor 6 recommended (abstract) | [10] |
The accelerated-acquisition data are volunteer abstracts from vendor-affiliated groups. They show that the scan time of B-TFE/B-TRANCE renal angiography can be reduced substantially without a measurable loss of image quality in healthy volunteers; they do not show equivalent diagnostic accuracy for renal artery stenosis in patients.
6. Vendor Implementations Compared
| Vendor | Product name [13] | What is documented in the verified sources |
|---|---|---|
| Philips | B-TRANCE | VCG-triggered balanced SSFP with slice-selective inversion; 3 T Ingenia work with Compressed SENSE; "balanced FFE" (1.5 T Achieva, portal vein) and "B-TFE" (3 T Ingenia CX, renal) readout names [8,9,10] |
| Siemens | NATIVE TrueFISP | Region inversion, ECG recommended, 1D PACE navigator, TI up to 1200–1400 ms, every-second-trigger rule, typical acquisition 2–5 minutes, uses in renal arteries, renal transplants and reduced stroke volume [14] |
| GE | Inhance Inflow IR | "3D fat-suppressed inflow inversion recovery balanced SSFP" (Inhance 3D Inflow IR) on a 3 T Signa HDxt in a 201-patient study [5]; 3 T inflow-enhanced IR bSSFP renal abstract with GE co-authors [12]; 1.5 T "inflow inversion recovery" in a 72-subject study [4] |
| Canon | Time-SLIP | Non-selective plus selective inversion; renal trials at 1.5 T [1,2] |
The Siemens, Canon and GE entries are the products of Edelman and Koktzoglou's Table 1 [13]. The mapping of Hitachi/Fujifilm (VASC-ASL) is discussed on the triggered NCE-MRA page and is not repeated here. One Chinese 1.5 T study of "inflow inversion recovery" [4] does not state the vendor in the retrieved abstract and is listed as a generic inflow-IR result.
7. Renal Evidence
The renal arteries are the territory with the strongest published evidence for inflow-IR bSSFP. All of the studies below are single-technique accuracy studies against a contrast-enhanced reference or DSA, mostly at 1.5 T.
| Study | Technique, field strength | Design | Result as reported |
|---|---|---|---|
| Wyttenbach 2007 [3] | Slab-selective inversion-prepared 3D SSFP, 1.5 T | Prospective, 53 patients, 108 arteries, CE-MRA reference | Per artery: sensitivity 100% / 95%, specificity 93% / 95% (two readers); stenosis overestimated (six and four false positives); maximal visible vessel length 61.1 mm vs 69.9 mm (P < .001) |
| Parienty 2011 [2] | Time-SLIP, flow-in 3D bSSFP, 1.5 T, regulated breathing | Prospective, 23 CKD patients, 45 arteries, DSA reference | Sensitivity 93% (26/28), specificity 88% (15/17), accuracy 91% (41/45) for ≥ 50% stenosis; Spearman ρ = 0.91; mean bias 2.33% (SD 11.95); image quality good in 87%, moderate in 13% |
| Albert 2015 (REACT trial) [1] | Time-SLIP with bSSFP | Multicentre, 75 patients, 161 arteries, CTA reference | Sensitivity 74%, specificity 93%, accuracy 90%; difference from CTA not statistically significant (p = 0.45); 16 misclassified arteries, 3 clinically relevant; image quality excellent in 75%, good in 21% |
| Xu 2017 [4] | Inflow inversion recovery, respiratory-gated, 1.5 T | 72 subjects, CE-MRA reference | Sensitivity 92–93%, specificity 98% for ≥ 50% stenosis; better branch visibility than CE-MRA; image quality better with stable breathing |
| Lal 2021 [5] | Inhance 3D Inflow IR, 3 T | 201 patients, 400 arteries, CE-MRA reference | Correct identification of 72 patients (95 arteries) with significant stenosis; two arteries underestimated as grade 2 (both grade 3 on CE-MRA); sensitivity and specificity not reported in the retrieved record |
| Bley 2010 [12] | Inflow-enhanced IR bSSFP, 3 T | Abstract; suspected RAS or transplant | Moderate agreement with CE-MRA for both readers; strong inter-observer agreement for stenosis above 50% |
| Glockner 2010 [6] | Inhance inflow-IR SSFP vs 3D CE-MRA | Title and DOI only (abstract not retrievable) | Not read; no result is claimed |
7.1 How to Read the Table
Three patterns recur. First, specificity is high (88–98% in the studies that report it). Second, sensitivity varies widely, from 74% in the multicentre REACT trial against CTA to 92–100% in the single-centre studies against CE-MRA or DSA; the study with the weakest sensitivity is the one with the most independent reference standard and the broadest centre mix, which suggests that single-centre figures may overstate performance (an inference, not a stated conclusion). Third, the direction of the grading error is not consistent: overestimation of stenosis in the earliest prospective study [3] and a slight positive bias in the Time-SLIP study [2], versus underestimation of two arteries in the 3 T Inhance study [5]. The REACT authors conclude that Time-SLIP "shows promise" and "may be" a safe alternative to contrast-enhanced CTA [1]; this page does not extend that to a general recommendation.
8. Territories Beyond the Renal Arteries
Edelman and Koktzoglou describe inflow-IR bSSFP's primary use as renal and abdominal arteries and note that it is "generally ineffective for peripheral arteries", where the triggered subtraction and QISS techniques of the angiography page are used [13]. Siemens lists NATIVE TrueFISP for renal transplants (usually without respiratory gating) and for patients with reduced stroke volume or dehydration [14]. For the hepatic portal vein, the verified evidence is the volunteer abstract of Section 4, in which TSE-based TRANCE outperformed the balanced FFE readout [8]. No verified evidence on thoracic, pulmonary or intracranial inflow-IR bSSFP was retrieved for this page.
9. Pitfalls and Failure Modes
| Problem | Evidence / mechanism | Mitigation |
|---|---|---|
| Irregular or deep breathing | Image quality significantly worse with unstable respiration [4]; irregular breathing degrades images [13] | Navigator, regulated breathing, breath-hold with acceleration (Section 5) |
| Slow flow, severe stenosis, short vessel length | Slow flow or severe distal stenosis limits visible vessel length [13]; shorter visible length than CE-MRA [3] | Adapt TI to flow and heart rate [15]; correlate with other imaging when findings are discordant |
| Stenosis over- or under-estimation | Overestimation [3], slight positive bias [2], underestimation of two arteries [5] | Interpret grade with caution; confirm borderline findings |
| Banding and susceptibility | bSSFP off-resonance behaviour (see bSSFP page); more sensitive than fast spin-echo [13] | Shim, short TR, centre-frequency adjustment |
| Assumed inflow direction | Selective-labelling methods assume known inflow direction, which can fail with retrograde flow or shunting [15] | Consider the haemodynamics before choosing the technique |
| Triggering failure | Inversion is played per trigger when ECG is used [14] | Verify the trigger signal; rely on the platform's TI/R–R rules |
10. Evidence Gaps and Ongoing Debate
- No guideline or consensus statement specific to inflow-IR bSSFP angiography was verified. All clinical claims rest on single studies and one multicentre trial.
- Philips-specific parameters are not quantified. TR, TE, flip angle, TI and voxel values for B-TRANCE were not available in the retrieved text (the parameter tables of the Philips-affiliated abstracts were images). Only the balanced-FFE portal-vein parameters of Section 4 and a GE 3 T inflow-IR example (TR/TE/TI 5.1/2.5/1300 ms [12]) are reported. Console labels are intentionally not enumerated.
- Two sources could not be read. The PubMed record of Glockner et al. (rate-limited) and a PubMed Central paper on axial versus coronal Time-SLIP acquisition (browser-check page) were not accessible; neither contributes a claim to this page.
- Inconsistent centre counts. The REACT trial is described as four centres in one bibliographic record and as seven centres in five countries in a press report; this page cites the bibliographic record's abstract data only and does not state a centre count.
- Vendor-affiliated abstracts. The b-TRANCE acceleration data [9,10] and the respiratory-triggered work [11] are conference abstracts with vendor-affiliated authors in small volunteer samples.
- Banding frequency in practice is not quantified for inflow-IR angiography; the worked numbers in Section 4.1 are arithmetic, and the recognition test is a logical inference.
- Which cardiac phase the readout occupies on each platform was not established in the retrieved sources.
11. Evidence-Based References
No official guideline, consensus statement, systematic review or meta-analysis specific to this technique was verified. References are listed by evidence tier and recency.
B. Consensus Statements
C. Important Prospective / Original Studies
Conference Abstracts (vendor-affiliated or abstract-only)
D. Technical MRI Papers and Reviews
End of document — Inflow Inversion-Recovery bSSFP Angiography (b-TFE / B-TRANCE) — MRIninja v1.0 — October 2026
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