BROOKLYN 3 MRI USER GROUP Anna Marie LYNDON

1. Sat 31stAug 2013 Session 2 / Talk 1 10:34 – 10:55 BROOKLYN 3 MRI USER GROUP Anna Marie LYNDON 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 1st 2011 and December 12th 2011. All studies were acquired on a 1.5T MagnetomAvanto 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.

2. Evaluation of QISSNon-CE MRA technique Anna-Maria Lydon, Andrew Holden Centre for Advanced MRI University of Auckland, New Zealand

3. SIEMENS WIP sequence - QISS • Background • Other non CE-MRA techniques • QISS – how it works • Recruitment • Challenges & limitations • Results • Case examples • Conclusion

4. Conventional CE-MRA sequences • Compares favourably with invasive catheter angiography • Still requires contrast media

5. SIEMENS non-CE MRA sequences • Native SPACE • A 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

6. Cine Scout Mean curve analysis

7. Femoro-popliteal Station CE-MRA NATIVE SPACE DSA

8. Tibial Station CE-MRA NATIVE SPACE

9. 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?) NATIVE SPACE CE-MRA

10. 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).

11. QISS – CAMRI Experience • 50 volunteers studied from March 1st to December 12th 2011 • Of these - 3 normal volunteers • - 47 clinical patients • 1.5T MagnetomAvanto 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

12. QISS – CAMRI Experience

13. QISS – Patient distribution 3 volunteers 2 Female – all stations 1 Male – foot and ankle 47 clinical patients 21 Female 26 Male Stations – Tibial (Std) - 16 Hi-res trifurcation - 6 Fem-pop - 17 Aorto-iliac - 14 Heart rate - Range 50-120bpm

14. QISS – Clinical Indications • 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

15. QISS – Limitations & challenges Venous Contamination- Our first clinical patient had the QISS sequence acquired in the abdominal (aorto-iliac) region post contrast. QISS #03 data set MIP

16. QISS – Limitations & challenges 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

17. 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 MIP QISS data set Ce-MRA MIP

18. QISS – Limitations & challenges Patient movement MIP’s often showed small steps between the stations. This was due to slight patient movement between slabs

19. 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.

20. QISS – Limitations & challenges SlowAF CE-MRA MIP SlowAF - QISS MIP Fast AF - CE-MRA MIP Fast AF - QISS MIP Arrhythmia & poor ECG - 6 patients presented with arrhythmia, eg, atrial fibrillation and bigeminy. In addition, 2 patients had poor ECG traces 1x patient had tachycardia (HR 115bpm)

21. QISS – Image Assessment • 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

22. QISS – Image Quality • Grade 1: non-diagnostic • Grade 2: poor quality • Grade 3: diagnostic • Grade 4: excellent quality Aorto-iliac Femoro-popliteal Tibial

23. QISS – Stenosis Severity • 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

24. QISS – Case examples QISS MIP CE-MRA Case #38 Aorto-iliac station (stations 6-8) 73yo Male Claudication both calves Fast AF – HR 115bpm

25. QISS – Case examples QISS MIP CE-MRA MIP Case #09 Femoro-popliteal stations Male ? SFA occlusion HR 62bpm

26. QISS – Case examples QISS MIP CE-MRA Case #46 56yo Male Severe left leg claudication AF 90 -120 bpm Hi-res trifurcation tibial station

27. QISS – Case examples Case #47 Male volunteer Researcher High-res foot & ankle station

28. Conclusion 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.

29. 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.

30. 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