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Imaging veins, oxygen extraction fraction, arteries and vessel wall using susceptibility weighted imaging (SWI) and susceptibility mapping (SWIM) SWI E. Mark Haacke Department of Radiology, Wayne State University Detroit, Michigan SWIM Conflicts of Interest • Support from Siemens Medical Systems • DoD grant on SWI and SWIM • NIH grant on USPIO susceptibility Qualitative SWI versus quantitative susceptibility mapping (QSM) or SWIM 0.5mm isotropic resolution, TE = 20ms, 3T SWI SWIM Imaging veins and blood products using SWI and SWIM1‐3 MRA SWI SWI MCI case TBI case SWI a SWIM b SWIM reversed c Imaging veins and blood products using SWI and SWIM: Challenging the neurovascular system4 200mg caffeine pills (a, d) or 1000mg diamox IV injection (c, f). SWI Compared to the control condition (b,e), significant oxygen saturation changes are observed post-challenge on veins throughout the brain. SWIM Caffeine: flow change = − 27% ± 9% and ΔY = − 0.09 ± 0.02 Diamox: flow change = +40% ± 7% and ΔY = +0.10 ± 0.01 Sequence diagram of the fully flow-compensated double-echo SWI sequence5 Image courtesy of Dongmei Wu FC1 FC2 FC3 Imaging veins and arteries using double echo SWI5 Images courtesy of Meiyun Wang, Zhengzhou Thrombus dominates the SWI image (TE = 7.5ms) Thrombus dominates the SWIM image (TE = 7.5ms) First echo MIP First echo MRA like signal Second echo (17.5ms) true SWI Note the asymmetrically prominent cortical veins First echo SWI phase image Imaging veins and arteries using an interleaved rephased/dephased double echo SWI6 250μ x 250μ x 500μ resolution Small arteries around 250 microns and possibly down to even 100 microns are becoming visible MRA short echo SWI RP-DP MRA Simultaneous MRV and MRI using a double echo interleaved SWI rephased/dephased sequence7 SWI only veins RP-DP MRA At 3T, veins are more naturally suppressed because they have T2* = 25ms while arteries have a T2* closer to 70-80ms. Images acquired with a resolution of 0.5mm x 0.5mm in-plane and 1mm thick slice. 0.5mm in-plane resolution. Images courtesy of Yongquan Ye, PhD MRI scan date: 2013.01.04 MTT SWI { MTT SWI MRI scan date: 2013.01.11 Imaging stroke patients with SWI and PWI8,9: Note that the MTT region indicating reduced perfusion matches the area highlighting the veins in the SWI image which corroborates the fact that flow is reduced and that the deoxyhemoglobin levels are increased in this territory. After treatment both the increases in MTT and evidence of the asymmetrically prominent cortical veins disappears. Images courtesy of Dr. Yu Luo. Visualizing Oxygen Extraction Fraction and Brain Iron Green ‐ deoxyhemoglobin levels in the veins Blue represents iron in the basal ganglia and midbrain Stroke: Isolating poor flow using a threshold in SWIM9,10 Imaging headache and idiopathic intracranial hypertension Asymmetrically prominent cortical veins are seen bilaterally Abnormal dural sinuses and jugular vein Imaging vessel wall using SWI and SWIM11,12 TE = 15.6ms 0.5mm x 0.5mm x 1mm sagittal acquisition 8 minutes without parallel imaging 2008 time frame 0.37 radian phase shift Carotid vessel wall plaque, TE = 5ms Carotid artery SWI and SWIM: Images courtesy of Hyun Seok Choi and Eo-Jin from Seoul, Korea SWIM magnitude MRA Flow compensated, TE = 5ms with an inplane resolution of 0.5mm x 0.5mm and 64 slices 2mm thick Scan time 4min, 36sec phase phase This may be a case of vulnerable plaque. Here you can see what appears to be a small thrombus on the inside wall. If that is the case, it could break off and become an embolus causing a stroke. SWIM validates it is iron and therefore likely blood. 1st Annual MRI Workshop on Stroke and Traumatic Brain Injury November 18‐19, 2014 ‐ Shenyang, China Held at Northeastern University (NEU) Representatives from the following cities presented: Academic speakers from Shanghai, Zhengzhou, Tianjin, Shenyang, Seoul, Detroit, and a speaker from Siemens Healthcare from Beijing AGENDA: GOALS FOR AN INTEGRATED STROKE IMAGING PROTOCOL • The use of SWI and SWIM in revealing changes in oxygen saturation • Intracranial black blood T1 imaging pre/post contrast to evaluate atherosclerosis • Monitoring patients from the acute to sub‐acute stage • Creating a database for this new 4‐tiered stroke protocol 2nd Annual MRI Workshop on Stroke and Traumatic Brain Injury • Tentatively scheduled for August, 2015 in Beijing Conclusions and Future Directions for Non‐contrast Uses of SWI/SWIM Imaging veins and arteries simultaneously using a multi‐echo SWI sequence Quantifying oxygen extraction fraction and iron Imaging vessel wall in the head, neck, abdomen and legs to study atherosclerosis and vulnerable plaque This talk can be found at www.swim‐mri.com 1) E.M. Haacke, Y. Xu, Y.C.N. Cheng, and J. Reichenbach. Susceptiblity Weighted Imaging (SWI). MRM 2004; 52:612‐618. 2) S. Mittal, Z. Wu, J. Neelavalli, and E.M. Haacke. Susceptibility‐Weighted Imaging: Technical Aspects and Clinical Applications, Part 2. AJNR 2009; 30:232‐252. 3) Haacke EM, Liu S, Buch S, Zheng W, Wu D, Ye Y. Quantitative susceptibility mapping: current status and future directions.Magn Reson Imaging. 2015 Jan;33(1):1‐25. doi: 10.1016/j.mri.2014.09.004. 4) Schweser F, Deistung A, Lehr BW, Reichenbach JR. Differentiation between diamagnetic and paramagnetic cerebral lesions based on magnetic susceptibility mapping. Med Phys. 2010; 37(10):5165‐78. 5) Dongmei Wu, Saifeng Liu, Sagar Buch, Yongquan Ye, Yongming Dai and E. Mark Haacke. A Fully Flow Compensated Multi‐echo Susceptibility Weighted Imaging Sequence: Acceleration and Background Field Effects on Flow Compensation ( manuscript submitted for publication to MRM). 6) Salamon, G., 1971. Atlas of the arteries of the human brain. Sandoz, Paris 7) E.M. Haacke and Y. Ye. The role of susceptibility weighted imaging in functional MRI. Neuroimage. 2012; 62(2):923‐929 PMID: 22245649. 8) M. Li, J. Hu, Y. Miao, H. Shen, D. Tao, Z. Yang, Q. Li, S.Y. Xuan, W. Raza, S. Alzubaidi, and E.M. Haacke. In vivo measurement of oxygenation changes after stroke using susceptibility weighted imaging filtered phase data. PLoS One. 2013 May 13; 8(5): e63013 PMID: 23675450. 9) S. Xia, D. Utriainen, J. Tang, Z. Kou, G. Zheng, X. Wang, W. Shen, E.M. Haacke, and G. Lu. Decreased oxygen saturation in asymmetrically prominent cortical veins in patients with cerebral ischemic stroke. Magn Reson Imaging. 2014 Aug 15. [Epub ahead of print] PMID: 25131626 10) J Liu, S Xia, R Hanks, N Wiseman, EM Haacke, Z Kou. Susceptibility Weighted Imaging and Mapping of Micro‐hemorrhages and Major Veins after Traumatic Brain Injury. Journal of Neurotrauma, 2015, accepted. 11) Q. Yang, J. Liu, S.R.S. Barnes, Z. Wu, K. Li, J. Neelavalli, J. Hu, and E.M. Haacke. Imaging the Vessel Wall in Major Peripheral Arteries using Susceptibility Weighted Imaging: Visualizing Calcifications. JMRI 2009; 30:357‐365. 12) S. Barnes and E.M. Haacke. Settling Properties of Venous Blood Demonstrated in the Peripheral Vasculature Using Susceptibility‐Weighted Imaging (SWI). JMRI 2009; 29:1465‐1470. Imaging macromolecular transport using SWIM Background Dr. Satish Kristhnamurthy from Syracuse University has previously shown that macromolecules (dextran) are transported from the ventricles into the brain tissue and are rapidly concentrated in the perivascular space surrounding microvessels throughout the brain. Hypothesis These macromolecules are then cleared from the perivascular space by passing through the endothelium and into the blood (via the venous system) and are transported out of the brain. Clearance of iron dextran for a normal rat versus delayed clearance for the hydrocephalic rat SWI (TE=7.71ms) at 7T pre, 1 hour and 1h30m for a normal rat (#7) (top row) and a hydrocephalic rat (#16) (bottom). The hydrocephalic rat has high Fe-Dextran concentration in the lateral ventricles compared to the normal rat. The injection side lateral ventricle has higher Fe-dextran concentration. Susceptibility maps can be used to follow the Fe-Dextran The timings are pre contrast, 50 minutes (central column) and 1.5h (right column). The dextran remained in the CSF channels, LV, 3rd ventricle aqueduct, 4th ventricle and resulted in higher concentration and permeated to the parenchyma from the CSF channels. SWIM showed no uptake in normal rats (first row) and significant uptake in the veins for the hydrocephalic rats over time (second row).