Improved T2* Imaging without Increase in Scan Time: SWI Processing of 2D Gradient Echo

Soman, Salil; Holdsworth, Samantha J.; Barnes, P. D.; Rosenberg, Jarrett; Andre, Jalal B.; Bammer, Roland; Yeom, Kristen W.

doi:10.3174/ajnr.a3595

Cited by 19 publications

(14 citation statements)

References 19 publications

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“…Another interesting observation was that only 70% of the iron laden lesions demonstrated hypointense signal on GRE-T2* weighted images whereas 98% of the lesions showed hypointensity on SWI in spite of similar slice thickness and in-plane resolution for both these images. In accordance to previous studies 31,32 , our observation suggests that SWI is more sensitive to susceptibility effects than GRE-T2* weighted images probably because SWI combines information both from phase and magnitude images to ascertain the local susceptibility changes among neighboring tissues whereas susceptibility contrast on GRE-T2* is mainly dependent on a combination of spin-spin relaxation (T2) and magnetic field inhomogeneity. We believe that inclusion of phase information renders SWI more sensitive to susceptibility effects than GRE-T2* images.…”

Section: Discussionsupporting

confidence: 91%

Iron and Non-Iron-Related Characteristics of Multiple Sclerosis and Neuromyelitis Optica Lesions at 7T MRI

Chawla

Kister

Wuerfel

et al. 2016

American Journal of Neuroradiology

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Background and Purpose To investigate the potential of ultra-high field MR imaging to distinguish multiple sclerosis (MS) from neuromyelitis optica (NMO) and to characterize tissue injury associated with iron pathology within lesions. Methods Twenty-one MS and 21 NMO patients underwent 7T high-resolution 2D-gradient-echo (GRE-T2*) and 3D-susceptibility weighted imaging (SWI). An in-house developed algorithm was used to reconstruct quantitative susceptibility mapping (QSM) from SWI. Lesions were classified as ‘iron laden’ if they demonstrated hypointensity on GRE-T2*- weighted images and/or SWI, and hyperintensity on QSM. Lesions were considered ‘non-iron laden’ if they were hyperintense on GRE-T2* and isointense or hyperintense on QSM. Results Of 21 MS patients, 19 (90.5%) demonstrated atleast one QSM-hyperintense lesion and 11/21 (52.4%) patients harbored iron-laden lesions. No QSM-hyperintense or iron-laden lesions were observed in any of the NMO patients. Iron-laden and non iron-laden lesions could each be further characterized into two distinct patterns based on lesion signal and morphology on GRE-T2*/SWI and QSM. In MS, the majority of lesions (n=262, 75.9% of all lesions) were hyperintense on GRE-T2* and isointense on QSM (Pattern A), while a small minority (n=26, 7.5% of all lesions) were hyperintense on both GRE-T2* and QSM (Pattern B). Iron laden lesions (n=57, 16.5% of all lesions) were further classified as ‘nodular’ (n=22, 6.4%, Pattern C) or ‘ring-like’ (n=35, 10.1%, Pattern D). Conclusions Ultra-high field MRI may be useful in distinguishing MS from NMO. Different patterns related to iron and non-iron pathology may provide in vivo insights into pathophysiology of lesions in MS.

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Section: Discussionsupporting

confidence: 91%

Iron and Non-Iron-Related Characteristics of Multiple Sclerosis and Neuromyelitis Optica Lesions at 7T MRI

Chawla

Kister

Wuerfel

et al. 2016

American Journal of Neuroradiology

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“…Moreover, as SWI is more susceptible to artifacts caused by calvaria, susceptibility artifacts arising from field inhomogeneities at the interfaces between bone and tissue, the detection of small SAH and SDH may be limited. Soman et al reported that GRE was superior to SWI with regard to T2* lesion conspicuity in one case with cortical venous thrombosis due to worsened calvarial artifacts adjacent to the T2* lesion [33].…”

Section: Discussionmentioning

confidence: 99%

Contrast-Enhanced FLAIR (Fluid-Attenuated Inversion Recovery) for Evaluating Mild Traumatic Brain Injury

et al. 2014

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PurposeTo evaluate whether adding a contrast-enhanced fluid-attenuated inversion recovery (FLAIR) sequence to routine magnetic resonance imaging (MRI) can detect additional abnormalities in the brains of symptomatic patients with mild traumatic brain injury.Materials and MethodsFifty-four patients with persistent symptoms following mild closed head injury were included in our retrospective study (M∶F = 32∶22, mean age: 59.8±16.4, age range: 26–84 years). All MRI examinations were obtained within 14 days after head trauma (mean: 3.2±4.1 days, range: 0.2–14 days). Two neuroradiologists recorded (1) the presence of traumatic brain lesions on MR images with and without contrast-enhanced FLAIR images and (2) the pattern and location of meningeal enhancement depicted on contrast-enhanced FLAIR images. The number of additional traumatic brain lesions diagnosed with contrast-enhanced FLAIR was recorded. Correlations between meningeal enhancement and clinical findings were also evaluated.ResultsTraumatic brain lesions were detected on routine image sequences in 25 patients. Three additional cases of brain abnormality were detected with the contrast-enhanced FLAIR images. Meningeal enhancement was identified on contrast-enhanced FLAIR images in 9 cases while the other routine image sequences showed no findings of traumatic brain injury. Overall, the additional contrast-enhanced FLAIR images revealed more extensive abnormalities than routine imaging in 37 cases (p<0.001). In multivariate logistic regression analysis, subdural hematoma and posttraumatic loss of consciousness showed a significant association with meningeal enhancement on contrast-enhanced FLAIR images, with odds ratios 13.068 (95% confidence interval 2.037 to 83.852), and 15.487 (95% confidence interval 2.545 to 94.228), respectively.ConclusionMeningeal enhancement on contrast-enhanced FLAIR images can help detect traumatic brain lesions as well as additional abnormalities not identified on routine unenhanced MRI. Therefore contrast-enhanced FLAIR MR imaging is recommended when a contrast MR study is indicated in a patient with a symptomatic prior closed mild head injury.

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“…Like other neuroimaging studies evaluating cerebral microhemorrhage presence, this study used an accepted GRE imaging sequence as the reference standard for CMH presence 8, 15, 27, 28 . Here, the three echoes of the 3D GRE magnitude images were used as ground truth for the presence of CMHs, given that direct pathological correlation was not possible (as is the case in many clinical imaging studies).…”

Section: Discussionmentioning

confidence: 99%

Brain Injury Lesion Imaging Using Preconditioned Quantitative Susceptibility Mapping without Skull Stripping

Soman¹,

Liu

Kim³

et al. 2018

AJNR Am J Neuroradiol

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Background and Purpose Identifying cerebral microhemorrhage (CMH) burden can aid in the diagnosis and management of traumatic brain injury (TBI), stroke, hypertension, and cerebral amyloid angiopathy. MRI susceptibility based methods are more sensitive than CT for detecting CMH, but methods other than quantitative susceptibility mapping (QSM) provide results that vary with field strength and echo times, require additional phase maps to distinguish blood from calcification and depict CMHs as bloom artifacts. QSM provides universal quantification of tissue magnetic property without these constraints, but traditionally requires a mask (mQSM) generated by skull-stripping, which can pose challenges at tissue interphases. We evaluate the preconditioned QSM (pQSM) MRI method, which does not require skull-stripping, for improved depiction of brain parenchyma and pathology. Materials and Methods 56 subjects underwent brain MRI with 3D multi-echo GRE acquisition. MQSM images were created using a commonly used mask based QSM method and pQSM images were made using precondition based total field inversion. All images were reviewed by a neuroradiologist and a radiology resident. Results 10 subjects (18%), all with TBI, demonstrated blood products on 3D GRE. All lesions were visible on pQSM, while 6 were not visible on mQSM. 31 subjects (55%) demonstrated brain parenchyma and/or lesions which were visible on pQSM but not on mQSM. 6 subjects (11%) demonstrated pons artifacts on pQSM and mQSM, worse on pQSM. Conclusion pQSM MRI can bring the benefits of QSM imaging to clinical practice without the limitations of mQSM, especially for evaluating CMH associated pathologies, such as TBI.

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Improved T2* Imaging without Increase in Scan Time: SWI Processing of 2D Gradient Echo

Cited by 19 publications

References 19 publications

Iron and Non-Iron-Related Characteristics of Multiple Sclerosis and Neuromyelitis Optica Lesions at 7T MRI

Iron and Non-Iron-Related Characteristics of Multiple Sclerosis and Neuromyelitis Optica Lesions at 7T MRI

Contrast-Enhanced FLAIR (Fluid-Attenuated Inversion Recovery) for Evaluating Mild Traumatic Brain Injury

Brain Injury Lesion Imaging Using Preconditioned Quantitative Susceptibility Mapping without Skull Stripping

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