Presentation on theme: "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."— Presentation transcript:
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 ( 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 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
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 1 st to December 12 th 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
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 Hi-res trifurcation - 6 Fem-pop - 17 Aorto-iliac - 14 Heart rate - Range 50-120bpm QISS – Patient distribution
Claudication – 31 Ulcers – 3 Other - ?PAD (specific level) - pulses (weak/absent) - 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 MIP QISS data set Ce-MRA MIP
Patient movement 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 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) QISS – Limitations & challenges Fast AF - CE-MRA MIP Slow AF - QISS MIP Slow AF CE-MRA MIP
Images independently reviewed by 3 vascular radiologists Images independently reviewed by 3 vascular radiologists Imaged are segments graded for image quality: Imaged are segments graded for image quality: Grade 1: non-diagnostic Grade 1: non-diagnostic Grade 2: poor quality Grade 2: poor quality Grade 3: diagnostic Grade 3: diagnostic Grade 4: excellent quality Grade 4: excellent quality Stenoses were colour coded as according to assessed severity Stenoses were colour coded as according to assessed severity QISS – Image Assessment
QISS – Stenosis Severity Correlation with CE-MRA Poor Excellent Image qualityNumber Non-diagnostic3 Poor7 Diagnostic14 Excellent23 QISS sequences compared to “gold standard” CE-MRA by 1 reviewer 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 QISS images of excellent and diagnostic quality compared well with CE-MRA, independent of site
Case #38 Aorto-iliac station (stations 6-8) 73yo Male Claudication both calves Fast AF – HR 115bpm QISS MIP CE-MRA QISS MIP CE-MRA QISS – Case examples
QISS MIP CE-MRA MIP QISS MIP CE-MRA MIP Case #09 Femoro-popliteal stations Male ? SFA occlusion HR 62bpm
56yo Male Severe left leg claudication AF 90 -120 bpm Hi-res trifurcation tibial station QISS – Case examples Case #46 QISS MIP CE-MRA QISS MIP CE-MRA
Case #47 Male volunteer Researcher 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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