Intraoperative acquisition of DTI in cranial neurosurgery: readout-segmented DTI versus standard single-shot DTI

2020 ◽  
Vol 133 (4) ◽  
pp. 1210-1219 ◽  
Author(s):  
Cameron A. Elliott ◽  
Hayden Danyluk ◽  
Keith E. Aronyk ◽  
Karolyn Au ◽  
B. Matt Wheatley ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Focal Cortical Dysplasia ◽  
High Grade Glioma ◽  
Cortical Dysplasia ◽  
Low Grade ◽  
Single Shot ◽  
Planar Imaging ◽  
Susceptibility Artifact ◽  
Echo Planar ◽  
Diffusion Tensor Imaging Dti

OBJECTIVEDiffusion tensor imaging (DTI) tractography is commonly used in neurosurgical practice but is largely limited to the preoperative setting. This is due primarily to image degradation caused by susceptibility artifact when conventional single-shot (SS) echo-planar imaging (EPI) DTI (SS-DTI) is acquired for open cranial, surgical position intraoperative DTI (iDTI). Readout-segmented (RS) EPI DTI (RS-DTI) has been reported to reduce such artifact but has not yet been evaluated in the intraoperative MRI (iMRI) environment. The authors evaluated the performance of RS versus SS EPI for DTI of the human brain in the iMRI setting.METHODSPre- and intraoperative 3-T 3D T1-weighted and 2D multislice RS-iDTI (called RESOLVE [readout segmentation of long variable echo-trains] on the Siemens platform) and SS-iDTI images were acquired in 22 adult patients undergoing intraaxial iMRI resections for suspected low-grade glioma (14; 64%), high-grade glioma (7; 32%), or focal cortical dysplasia. Regional susceptibility artifact, anatomical deviation relative to T1-weighted imaging, and tractographic output for surgically relevant tracts were compared between iDTI sequences as well as the intraoperative tract shifts from preoperative DTI.RESULTSRS-iDTI resulted in qualitatively less regional susceptibility artifact (resection cavity, orbitofrontal and anterior temporal cortices) and mean anatomical deviation in regions most prone to susceptibility artifact (RS-iDTI 2.7 ± 0.2 vs SS-iDTI 7.5 ± 0.4 mm) compared to SS-iDTI. Although tract reconstruction success did not significantly differ by DTI method, susceptibility artifact–related tractography failure (of at least 1 surgically relevant tract) occurred for SS-iDTI in 8/22 (36%) patients, and in 5 of these 8 patients RS-iDTI permitted successful reconstruction. Among cases with successful tractography for both sequences, maximal intersequence differences were substantial (mean 9.5 ± 5.7 mm, range −27.1 to 18.7 mm).CONCLUSIONSRS EPI enables higher quality and more accurate DTI for surgically relevant tractography of major white matter tracts in intraoperative, open cranium neurosurgical applications at 3 T.

scholarly journals GP.05 Intraoperative acquisition of diffusion tensor imaging in cranial neurosurgery: readout-segmented DTI versus standard single-shot DTI

2019 ◽  
Vol 46 (s1) ◽  
pp. S7
Author(s):  
CA Elliott ◽  
B Wheatley ◽  
H Danyluk ◽  
K Au ◽  
KE Aronyk ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
High Grade Glioma ◽  
Low Grade ◽  
Single Shot ◽  
Planar Imaging ◽  
Susceptibility Artifact ◽  
Echo Planar ◽  
Diffusion Tensor Imaging Dti

Background: Diffusion-tensor imaging (DTI) tractography is commonly used in neurosurgical practice, but is largely limited to the preoperative setting. This is due primarily to image degradation caused by susceptibility artifact when conventional single-shot (SS) echo-planar imaging DTI is acquired for open cranial, surgical position intraoperative DTI (iDTI). A novel, artifact-resistant, readout-segmented (RS) DTI has not yet been evaluated in the intraoperative MRI (iMRI) environment. Our objective was to evaluate the performance of RS-DTI versus SS-DTI for intraoperative white matter imaging. Methods: Pre- and intraoperative 3T, T1-weighted and DTI (RS-iDTI and SS-iDTI) in 22 adults undergoing intraaxial iMRI resections (low-grade glioma: 14, 64%; high-grade glioma: 7, 32%; cortical dysplasia: 1). Regional susceptibility artifact, anatomical deviation relative to T1WI, and tractographic output were compared between iDTI sequences. Results: RS-iDTI resulted in less regional susceptibility artifact and mean anatomic deviation (RS-iDTI: 2.7±0.2 mm versus SS-iDTI 7.5±0.4 mm; p<0.0001). Tractographic failure occurred in 8/22 (36%) patients for SS-iDTI whereas RS-iDTI permitted successful reconstruction in 4 of these 8. Maximal tractographic differences between DTI sequences were substantial (mean 9.7±5.7 mm). Conclusions: Readout-segmented EPI enables higher quality and more accurate DTI for surgically relevant tractography of major white matter tracts in intraoperative, open cranium, neurosurgical applications at 3T.

scholarly journals Fractional anisotropy thresholding for deterministic tractography of the roots of the brachial plexus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryckie G. Wade ◽  
Irvin Teh ◽  
Gustav Andersson ◽  
Fang-Cheng Yeh ◽  
Mikael Wiberg ◽  
...  
Keyword(s):  
Brachial Plexus ◽  
Fractional Anisotropy ◽  
Diffusion Tensor ◽  
B Value ◽  
Spinal Nerve ◽  
Single Shot ◽  
Planar Imaging ◽  
Deterministic Tractography ◽  
Echo Planar ◽  
The Brain

AbstractDiffusion tensor imaging (DTI) metrics, such as the fractional anisotropy (FA) and estimates of diffusivity are sensitive to the microstructure of peripheral nerves and may be displayed as tractograms. However, the ideal conditions for tractography of the roots of the brachial plexus are unclear, which represents the rationale for this study. Ten healthy adults were scanned using a Siemens Prisma (3T) and single-shot echo-planar imaging (b-value 0/1000 s/mm2, 64 directions, 2.5 mm3 with 4 averages; repeated in opposing phase encoding directions). Susceptibility correction and tractography were performed in DSI Studio by two independent raters. The effect of FA thresholding at increments of 0.01 (from 0.04 to 0.10) were tested. The mean FA varied between subjects by 2% (95% CI 1%, 3%). FA thresholds of 0.04, 0.05 and 0.06 all propagated 96% of tracts representing the roots; thresholding at 0.07 yielded 4% fewer tracts (p = 0.2), 0.08 yielded 11% fewer tracts (p = 0.008), 0.09 yielded 15% fewer tracts (p = 0.001) and 0.1 yielded 20% fewer tracts (p < 0.001). There was < 0.1% inter-rater variability in the measured FA and 99% agreement for tractography (κ = 0.92, p < 0.001). The fractional anisotropy thresholds required to generate tractograms of the roots of the brachial plexus appears to be lower than those used in the brain. We provide estimates of the probability of generating true tracts for each spinal nerve root of the brachial plexus, at different fractional anisotropy thresholds.

scholarly journals Diffusion Tensor Imaging of the Brachial Plexus: A Comparison between Readout-segmented and Conventional Single-shot Echo-planar Imaging

2019 ◽  
Vol 18 (2) ◽  
pp. 150-157 ◽  
Author(s):  
Michael J. Ho ◽  
Alexander Ciritsis ◽  
Andrei Manoliu ◽  
Bram Stieltjes ◽  
Magda Marcon ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Brachial Plexus ◽  
Diffusion Tensor ◽  
Echo Planar Imaging ◽  
Single Shot ◽  
Planar Imaging ◽  
Echo Planar

scholarly journals Embolic Complications of Endovascular Surgery for Cerebrovascular Diseases Evaluation with Diffusion-Weighted MR Imaging

2000 ◽  
Vol 6 (1_suppl) ◽  
pp. 223-226 ◽  
Author(s):  
H. Sakai ◽  
N. Sakai ◽  
I. Nakahara ◽  
T. Shimozuru ◽  
T. Higashi ◽  
...  
Keyword(s):  
Mr Imaging ◽  
B Value ◽  
Cerebrovascular Diseases ◽  
Endovascular Surgery ◽  
Single Shot ◽  
Planar Imaging ◽  
Diffusion Weighted ◽  
Screening Study ◽  
Cerebral Ischemic ◽  
Echo Planar

The purpose of this study was to evaluate asymptomatic embolisms during cerebral endovascular surgery for cerebrovascular diseases with diffusion-weighted magnetic resonance imaging (DWI) which allowed sensitive and early detection of cerebral ischemic lesions. 71 patients who underwent a total of 74 cerebral endovascular procedures were subjected to DWI screening study. MR imaging was performed on a 1.5T system by using single-shot SE echo-planar imaging (EPI) with b value of 1100 seconds per mm2 in pre- and post-treatment periods (between day 2 and 5 after procedures). In 38 (51.3%) of 74 procedures, new high intensity lesions, as recent infarctions related to procedures, were detected on post-procedural DWI. In 18 Of the patients (47.4%), symptomatic infarctions occurred and resulted in TIAs (n = 4), RINDs (n = 8), minor strokes (n = 6) and no major strokes and no death. 20 (52.6%) of the recent infarctions detected by DWI were asymptomatic lesions. Most of the asymptomatic ischemic lesions were likely to be distributed in watershed border areas. On the other hand, symptomatic lesions tended to be distributed in cortical and/or perforator regions and to be multiple. Thus, DWI is a useful method that can detect neurologically silent and asymptomatic ischemic lesions. It can be used to help to evaluate the safety and efficacy of neurovascular intervention.

scholarly journals Magnetic Resonance Fingerprinting with Combined Gradient- and Spin-echo Echo-planar Imaging: Simultaneous Estimation of T1, T2 and T2* with integrated-B1 Correction

2019 ◽  
Author(s):  
Mahdi Khajehim ◽  
Thomas Christen ◽  
J. Jean Chen
Keyword(s):  
Magnetic Resonance ◽  
Spin Echo ◽  
Echo Planar Imaging ◽  
Simultaneous Estimation ◽  
Single Shot ◽  
Planar Imaging ◽  
Reconstruction Process ◽  
Data Segment ◽  
T1 And T2 ◽  
Echo Planar

AbstractPurposeTo introduce a novel magnetic-resonance fingerprinting (MRF) framework with single-shot echo-planar imaging (EPI) readout to simultaneously estimate tissue T2, T1 and T2*, and integrate B1 correction.MethodsSpin-echo EPI is combined with gradient-echo EPI to achieve T2 estimation as well as T1 and T2* quantification. In the dictionary matching step, the GE-EPI data segment provides estimates of tissue T1 and T2* with additional B1 information, which are then incorporated into the T2-matching step that uses the SE-EPI data segment. In this way, biases in T2 and T2* estimates do not affect each other.ResultsAn excellent correspondence was found between our T1, T2, and T2* estimates and results obtained from standard approaches in both phantom and human scans. In the phantom scan, a linear relationship with R2>0.96 was found for all parameter estimates. The maximum error in the T2 estimate was found to be below 6%. In the in-vivo scan, similar contrast was noted between MRF and standard approaches, and values found in a small region of interest (ROI) located in the grey matter (GM) were in line with previous measurements (T2MRF=88±7ms vs T2Ref=89±11ms, T1MRF=1153±154ms vs T1Ref=1122±52ms, T2*MRF=56±4ms vs T2*Ref=53±3ms).ConclusionAdding a spin echo data segment to EPI based MRF allows accurate and robust measurements of T2, T1 and T2* relaxation times. This MRF framework is easier to implement than spiral-based MRF. It doesn’t suffer from undersampling artifacts and seems to require a smaller dictionary size that can fasten the reconstruction process.

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