BROOKLYN 3 MRI USER GROUP Anna Marie LYNDON Sat 31 st Aug 2013 Session 2 / Talk 1 10:34 – 10:55 ABSTRACT In this study we assessed a Works-in-Progress sequence developed by Siemens for evaluation of the peripheral arterial tree without contrast agent - Quiescent Interval Single Shot MR Angiography (QISS) sequence. Previously we have evaluated other non-contrast enhanced angiographic techniques (Native Space and Native TrueFisp) which worked well in the majority of regions but still presented some limitations. It was hoped that the new technique using the inflow of non-saturated blood spins & acquiring single-shot 2D TrueFISP readout images might improve detection and accuracy of lesions, particularly in the abdominal and pelvic region. A total of 50 volunteers were recruited between March 1 st 2011 and December 12 th 2011. All studies were acquired on a 1.5T Magnetom Avanto scanner (Siemens, Erlangen, Germany). The first two participants were healthy volunteers, followed by 48 clinical patients. The images were independently reviewed by 3 Vascular Radiologists blinded to patient details. Diseased arterial segments were assessed as normal, stenosed or occluded. Stenosis severity was assessed as mild (< 50% diameter loss), moderate (50-70% diameter loss) and severe (> 70% diameter loss). Stenosis and occlusion length were also assessed. These findings were then compared to the “gold standard” CE-MRA to allow assessment of accuracy of the QISS sequence in assessing arterial disease severity and extent. The QISS sequence produced images that corresponded very well with the contrast enhanced images of the same anatomical regions. Stenoses and occlusions were accurately assessed in the majority of cases. We present our findings and show some examples of the strengths and weaknesses of this Works-in-Progress technique.
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BROOKLYN 3MRI USER GROUP
Anna Marie LYNDON
Sat 31st Aug 2013Session 2 / Talk 1
10:34 – 10:55
ABSTRACTIn this study we assessed a Works-in-Progress sequence developed by Siemens for evaluation of the peripheral arterial tree without contrast agent - Quiescent Interval Single Shot MR Angiography (QISS) sequence.Previously we have evaluated other non-contrast enhanced angiographic techniques (Native Space and Native TrueFisp) which worked well in the majority of regions but still presented some limitations. It was hoped that the new technique using the inflow of non-saturated blood spins & acquiring single-shot 2D TrueFISP readout images might improve detection and accuracy of lesions, particularly in the abdominal and pelvic region.A total of 50 volunteers were recruited between March 1st 2011 and December 12th 2011. All studies were acquired on a 1.5T Magnetom Avanto scanner (Siemens, Erlangen, Germany). The first two participants were healthy volunteers, followed by 48 clinical patients.The images were independently reviewed by 3 Vascular Radiologists blinded to patient details. Diseased arterial segments were assessed as normal, stenosed or occluded. Stenosis severity was assessed as mild (< 50% diameter loss), moderate (50-70% diameter loss) and severe (> 70% diameter loss). Stenosis and occlusion length were also assessed.These findings were then compared to the “gold standard” CE-MRA to allow assessment of accuracy of the QISS sequence in assessing arterial disease severity and extent.The QISS sequence produced images that corresponded very well with the contrast enhanced images of the same anatomical regions. Stenoses and occlusions were accurately assessed in the majority of cases.We present our findings and show some examples of the strengths and weaknesses of this Works-in-Progress technique.
Evaluation of QISS
Non-CE MRA technique
Anna-Maria Lydon, Andrew Holden Centre for Advanced MRI
University of Auckland, New Zealand
Background Other non CE-MRA techniques QISS – how it works Recruitment Challenges & limitations Results Case examples Conclusion
SIEMENS WIP sequence - QISS
Conventional CE-MRA sequences
Compares favourably with invasive catheter angiography
Still requires contrast media
SIEMENS non-CE MRA sequences
Native SPACEA technique that relies on the inherent difference in signal between fast flowing blood in systole and the slower flowing blood in the diastolic phase of the cardiac cycle
It is a high spatial resolution 3D TSE sequence with contrast optimized variable flip-angle trains and inherent flow sensitivity
Cine Scout Mean curve analysis
Femoro-popliteal Station
CE-MRA
NATIVE SPACE
DSA
Tibial Station
CE-MRA
NATIVE SPACE
Aorto-iliac Station All 4 cases assessed as poor quality Poor vessel signal intensity obtained from
the aorta and iliac vessels but femoral vessels well seen (S:N issues?)
CE-MRA
NATIVESPACE
SIEMENS WIP sequence - QISS Quiescent-Interval Single Shot Magnetic
Resonance Angiography (QISS) Rapid, sequential two-dimensional (2D) steady-state free
precession acquisition acquired using ECG-gating Acquires one slice per heartbeat
Figure 1. Pulse sequence diagram of the QISS sequence (Edelman et al, MRM 2009).
QISS – CAMRI Experience 50 volunteers studied from March 1st to
December 12th 2011
Of these - 3 normal volunteers- 47 clinical patients
1.5T Magnetom Avanto scanner (Siemens, Erlangen, Germany) using a dedicated peripheral vascular coil and body matrix coils as required
Image quality assessed and graded from non-diagnostic to excellent
QISS – CAMRI Experience
3 volunteers 2 Female – all stations
1 Male – foot and ankle
47 clinical patients 21 Female26 Male
Stations – Tibial (Std) - 16 Hi-res trifurcation - 6
Fem-pop - 17Aorto-iliac - 14
Heart rate - Range 50-120bpm
QISS – Patient distribution
Claudication – 31 Ulcers – 3 Other - ?PAD (specific level)
- pulses (weak/absent)- 1 x Type B aortic dissection- 2 x aneurysms (AAA and iliac)- 1 x toe numbness- Previous grafts/ PTA- 1 x amputee with weak pulses
remaining limb- 5 x TKJR, 1 x THJR
QISS – Clinical Indications
Venous Contamination - Our first clinical patient had the QISS sequence acquired in the abdominal (aorto-iliac) region post contrast.
QISS – Limitations & challenges
QISS #03 data set MIP
In-Plane Signal Loss - be seen when the vessel orientation runs in-plane with the slice orientation. CE-MRA MIP QISS MIP QISS angled slab
showing signal loss
QISS – Limitations & challenges
Abdominal (aortio-iliac) region – - The initial healthy volunteers struggled with the breath-holds- By adapting the abdominal (aorto-iliac) regions to a single concatenation with 2-3 averages this sequence could be acquired with free breathing
QISS – Limitations & challenges
MIP QISS data set Ce-MRA MIP
Patient movement
MIP’s often showed small steps between the stations. This was due to slight patient movement between slabs
QISS – Limitations & challenges
QISS MIP Ce-MRA MIP
Metal Artifact – 5 of the clinical volunteers had a total knee joint replacements and 1 had a total hip joint replacement.
QISS – Limitations & challenges
Fast AF - QISS MIP
Arrhythmia & poor ECG - 6 patients presented with arrhythmia, eg, atrial fibrillation and bigeminy. In addition, 2 patients had poor ECG traces1x patient had tachycardia (HR 115bpm)
QISS – Limitations & challenges
Fast AF - CE-MRA MIP
Slow AF - QISS MIP
Slow AF CE-MRA MIP
Images independently reviewed by 3 vascular radiologists Imaged are segments graded for image quality:
Grade 1: non-diagnostic Grade 2: poor quality Grade 3: diagnostic Grade 4: excellent quality
Stenoses were colour coded as according to assessed severity
QISS – Image Assessment
Grade 1: non-diagnostic Grade 2: poor quality Grade 3: diagnostic Grade 4: excellent quality
QISS – Image Quality
Grade NumberN=14
1 2 2 2 3 4 4 6
Grade NumberN=17
1 1 2 3 3 6 4 7
Grade NumberN=16
1 0 2 2 3 4 4 10
Aorto-iliac Femoro-popliteal Tibial
QISS – Stenosis Severity
Correlation with CE-MRA Poor Poor Excellent Excellent
Image quality Number Non-diagnostic 3 Poor 7 Diagnostic 14 Excellent 23
QISS sequences compared to “gold standard” CE-MRA by 1 reviewer
QISS images of excellent and diagnostic quality compared well with CE-MRA, independent of site
Case #38 Aorto-iliac station (stations 6-8)73yo MaleClaudication both calvesFast AF – HR 115bpm QISS MIP CE-MRA
QISS – Case examples
QISS – Case examples
QISS MIP CE-MRA MIP
Case #09 Femoro-popliteal stationsMale? SFA occlusionHR 62bpm
56yo MaleSevere left leg claudicationAF 90 -120 bpmHi-res trifurcation tibial station
QISS – Case examplesCase #46
QISS MIP CE-MRA
Case #47Male volunteerResearcher High-res foot & ankle station
QISS – Case examples
In our experience the QISS sequence has been a robust and relatively easy sequence to run We have found it quick and easy to use Potentially is of great use in cases where patients are unable to have Gadolinium contrast agent. However – there are pitfalls to be aware of.
Conclusion
References Bi, X & Glielmi, C (2010), ‘Non contrast-enhanced,
Quiescent Interval Single Shot (QISS) MR Angiography of the Peripheral Arteries’, Siemens Applications Guide (Works-in-Progress # 592).
Eldelman RR, Sheehan JJ, Dunkle E, Schindler N, Carr J, Koktzoglou I (2010), ‘Quiescent-Interval Single-Shot Unenhanced Magnetic Resonance Angiography of Peripheral Vascular Disease: Technical Considerations and Clinical Feasibility’, Magnetic Resonance in Medicine, vol. 63, pp. 951-8.
Acknowledgements Dr Andrew Holden, Dr Brett Cowan,
Kate Handley, Hilary McIntyre, Rachel Heron and all the team at CAMRI
Dr Peter Schmitt, Dr Andreas Greiser & the CV development team at Siemens, Erlangen
All our patients who volunteered
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