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Warntjes, M. J., Blystad, I., Tisell, A. & Larsson, E.-M. -. (2018). Synthesizing a Contrast-Enhancement Map in Patients with High-Grade Gliomas Based on a Postcontrast MR Imaging Quantification Only. American Journal of Neuroradiology, 39(12), 2194-2199
Open this publication in new window or tab >>Synthesizing a Contrast-Enhancement Map in Patients with High-Grade Gliomas Based on a Postcontrast MR Imaging Quantification Only
2018 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 39, no 12, p. 2194-2199Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND PURPOSE: Administration of a gadolinium-based contrast agent is an important diagnostic biomarker for blood-brain barrier damage. In clinical use, detection is based on subjective comparison of native and postgadolinium-based contrast agent T1-weighted images. Quantitative MR imaging studies have suggested a relation between the longitudinal relaxation rate and proton-density in the brain parenchyma, which is disturbed by gadolinium-based contrast agents. This discrepancy can be used to synthesize a contrast-enhancement map based solely on the postgadolinium-based contrast agent acquisition. The aim of this study was to compare synthetic enhancement maps with subtraction maps of native and postgadolinium-based contrast agent images. MATERIALS AND METHODS: For 14 patients with high-grade gliomas, quantitative MR imaging was performed before and after gadolinium-based contrast agent administration. The quantification sequence was multidynamic and multiecho, with a scan time of 6 minutes. The 2 image stacks were coregistered using in-plane transformation. The longitudinal relaxation maps were subtracted and correlated with the synthetic longitudinal relaxation enhancement maps on the basis of the postgadolinium-based contrast agent images only. ROIs were drawn for tumor delineation. RESULTS: Linear regression of the subtraction and synthetic longitudinal relaxation enhancement maps showed a slope of 1.02 0.19 and an intercept of 0.05 +/- 0.12. The Pearson correlation coefficient was 0.861 +/- 0.059, and the coefficient of variation was 0.18 +/- 0.04. On average, a volume of 1.71 +/- 1.28 mL of low-intensity enhancement was detected in the synthetic enhancement maps outside the borders of the drawn ROI. CONCLUSIONS: The study shows that there was a good correlation between subtraction longitudinal relaxation enhancement maps and synthetic longitudinal relaxation enhancement maps in patients with high-grade gliomas. The method may improve the sensitivity and objectivity for the detection of gadolinium-based contrast agent enhancement.

Place, publisher, year, edition, pages
AMER SOC NEURORADIOLOGY, 2018
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-153692 (URN)10.3174/ajnr.A5870 (DOI)000452729200013 ()30409854 (PubMedID)
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-05-01
Blystad, I. (2017). Clinical Applications of Synthetic MRI of the Brain. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Clinical Applications of Synthetic MRI of the Brain
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Magnetic Resonance Imaging (MRI) has a high soft-tissue contrast with a high sensitivity for detecting pathological changes in the brain. Conventional MRI is a time-consuming method with multiple scans that relies on the visual assessment of the neuroradiologist. Synthetic MRI uses one scan to produce conventional images, but also quantitative maps based on relaxometry, that can be used to quantitatively analyse tissue properties and pathological changes. The studies presented here apply the use of synthetic MRI of the brain in different clinical settings.

In the first study, synthetic MR images were compared to conventional MR images in 22 patients. The contrast, the contrast-to-noise ratio, and the diagnostic quality were assessed. Image quality was perceived to be inferior in the synthetic images, but synthetic images agreed with the clinical diagnoses to the same extent as the conventional images.

Patients with early multiple sclerosis were analysed in the second study. In patients with multiple sclerosis, contrast-enhancing white matter lesions are a sign of active disease and can indicate a need for a change in therapy. Gadolinium-based contrast agents are used to detect active lesions, but concern has been raised regarding the long-term effects of repeated use of gadolinium. In this study, relaxometry was used to evaluate whether pre-contrast injection tissue-relaxation rates and proton density can identify active lesions without gadolinium. The findings suggest that active lesions often have relaxation times and proton density that differ from non-enhancing lesions, but with some overlap. This makes it difficult to replace gadolinium-based contrast agent injection with synthetic MRI in the monitoring of MS patients.

Malignant gliomas are primary brain tumours with contrast enhancement due to a defective blood-brain barrier. However, they also grow in an infiltrative, diffuse manner, making it difficult to clearly delineate them from surrounding normal brain tissue in the diagnostic workup, at surgery, and during follow-up. The contrast-enhancing part of the tumour is easily visualised, but not the diffuse infiltration. In studies three and four, synthetic MRI was used to analyse the peritumoral area of malignant gliomas, and revealed quantitative findings regarding peritumoral relaxation changes and non-visible contrast enhancement suggestive of non-visible infiltrative tumour growth.

In conclusion, synthetic MRI provides quantitative information about the brain tissue and this could improve the diagnosis and treatment for patients.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2017. p. 77
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1600
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-143032 (URN)10.3384/diss.diva-143032 (DOI)9789176854136 (ISBN)
Public defence
2017-12-13, Berzeliussalen, Campus US, Linköping, 09:00 (English)
Opponent
Supervisors
Available from: 2017-11-16 Created: 2017-11-16 Last updated: 2019-10-28Bibliographically approved
Blystad, I., Warntjes, M. J., Smedby, Ö., Lundberg, P., Larsson, E.-M. & Tisell, A. (2017). Quantitative MRI for analysis of peritumoral edema in malignant gliomas. PLoS ONE, 12(5), Article ID e0177135.
Open this publication in new window or tab >>Quantitative MRI for analysis of peritumoral edema in malignant gliomas
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2017 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 5, article id e0177135Article in journal (Refereed) Published
Abstract [en]

Background and purpose Damage to the blood-brain barrier with subsequent contrast enhancement is a hallmark of glioblastoma. Non-enhancing tumor invasion into the peritumoral edema is, however, not usually visible on conventional magnetic resonance imaging. New quantitative techniques using relaxometry offer additional information about tissue properties. The aim of this study was to evaluate longitudinal relaxation R-1, transverse relaxation R-2, and proton density in the peritumoral edema in a group of patients with malignant glioma before surgery to assess whether relaxometry can detect changes not visible on conventional images. Methods In a prospective study, 24 patients with suspected malignant glioma were examined before surgery. A standard MRI protocol was used with the addition of a quantitative MR method (MAGIC), which measured R-1, R-2, and proton density. The diagnosis of malignant glioma was confirmed after biopsy/surgery. In 19 patients synthetic MR images were then created from the MAGIC scan, and ROIs were placed in the peritumoral edema to obtain the quantitative values. Dynamic susceptibility contrast perfusion was used to obtain cerebral blood volume (rCBV) data of the peritumoral edema. Voxel-based statistical analysis was performed using a mixed linear model. Results R-1, R-2, and rCBV decrease with increasing distance from the contrast-enhancing part of the tumor. There is a significant increase in R1 gradient after contrast agent injection (Pamp;lt;.0001). There is a heterogeneous pattern of relaxation values in the peritumoral edema adjacent to the contrast-enhancing part of the tumor. Conclusion Quantitative analysis with relaxometry of peritumoral edema in malignant gliomas detects tissue changes not visualized on conventional MR images. The finding of decreasing R-1 and R-2 means shorter relaxation times closer to the tumor, which could reflect tumor invasion into the peritumoral edema. However, these findings need to be validated in the future.

Place, publisher, year, edition, pages
PUBLIC LIBRARY SCIENCE, 2017
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-138480 (URN)10.1371/journal.pone.0177135 (DOI)000402058800007 ()28542553 (PubMedID)
Note

Funding Agencies|Medical Research Council of Southeast Sweden [FORSS-234551]

Available from: 2017-06-19 Created: 2017-06-19 Last updated: 2018-04-17
Blystad, I., Håkansson, I., Tisell, A., Ernerudh, J., Smedby, Ö., Lundberg, P. & Larsson, E.-M. (2016). Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent. American Journal of Neuroradiology, 37(1), 94-100
Open this publication in new window or tab >>Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent
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2016 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 37, no 1, p. 94-100Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND PURPOSE: Contrast-enhancing MS lesions are important markers of active inflammation in the diagnostic work-up of MS and in disease monitoring with MR imaging. Because intravenous contrast agents involve an expense and a potential risk of adverse events, it would be desirable to identify active lesions without using a contrast agent. The purpose of this study was to evaluate whether pre-contrast injection tissue-relaxation rates and proton density of MS lesions, by using a new quantitative MR imaging sequence, can identify active lesions. MATERIALS AND METHODS: Forty-four patients with a clinical suspicion of MS were studied. MR imaging with a standard clinical MS protocol and a quantitative MR imaging sequence was performed at inclusion (baseline) and after 1 year. ROIs were placed in MS lesions, classified as nonenhancing or enhancing. Longitudinal and transverse relaxation rates, as well as proton density were obtained from the quantitative MR imaging sequence. Statistical analyses of ROI values were performed by using a mixed linear model, logistic regression, and receiver operating characteristic analysis. RESULTS: Enhancing lesions had a significantly (P < .001) higher mean longitudinal relaxation rate (1.22 0.36 versus 0.89 +/- 0.24), a higher mean transverse relaxation rate (9.8 +/- 2.6 versus 7.4 +/- 1.9), and a lower mean proton density (77 +/- 11.2 versus 90 +/- 8.4) than nonenhancing lesions. An area under the receiver operating characteristic curve value of 0.832 was obtained. CONCLUSIONS: Contrast-enhancing MS lesions often have proton density and relaxation times that differ from those in nonenhancing lesions, with lower proton density and shorter relaxation times in enhancing lesions compared with nonenhancing lesions.

Place, publisher, year, edition, pages
AMER SOC NEURORADIOLOGY, 2016
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-124482 (URN)10.3174/ajnr.A4501 (DOI)000367466500019 ()26471751 (PubMedID)
Note

Funding Agencies|National Science and Engineering Research Council; University of Linkoping; University Hospital Research Funds

Available from: 2016-02-02 Created: 2016-02-01 Last updated: 2017-11-16
Bertus Warntjes, M. J., Blystad, I., Tisell, A. & Lundberg, P. (2014). Obtaining Double Inversion Recovery and Phase Sensitive Inversion Recovery Images without additional Scan Time. In: : . Paper presented at Radiological Society of North America, (RSNA) 2014, Chicago, USA..
Open this publication in new window or tab >>Obtaining Double Inversion Recovery and Phase Sensitive Inversion Recovery Images without additional Scan Time
2014 (English)Conference paper, Poster (with or without abstract) (Other academic)
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-114351 (URN)
Conference
Radiological Society of North America, (RSNA) 2014, Chicago, USA.
Available from: 2015-02-19 Created: 2015-02-19 Last updated: 2015-04-14
Blystad, I., Håkansson, I., Tisell, A., Ernerudh, J., Smedby, Ö., Lundberg, P. & Larsson, E. (2014). Quantitative MRI for the evaluation of active MS-lesions without gadolinium based contrast agent.. In: : . Paper presented at World Federation of Neuroradiological Societies - WFNRS 2014 (Istanbul Turky).
Open this publication in new window or tab >>Quantitative MRI for the evaluation of active MS-lesions without gadolinium based contrast agent.
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2014 (English)Conference paper, Poster (with or without abstract) (Other academic)
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-114321 (URN)
Conference
World Federation of Neuroradiological Societies - WFNRS 2014 (Istanbul Turky)
Available from: 2015-02-18 Created: 2015-02-18 Last updated: 2015-04-14
West, J., Blystad, I., Engström, M., Warntjes, M. J. & Lundberg, P. (2013). Application of Quantitative MRI for Brain Tissue Segmentation at 1.5 T and 3.0 T Field Strengths. PLoS ONE, 8(9)
Open this publication in new window or tab >>Application of Quantitative MRI for Brain Tissue Segmentation at 1.5 T and 3.0 T Field Strengths
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2013 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 9Article in journal (Refereed) Published
Abstract [en]

Background

Brain tissue segmentation of white matter (WM), grey matter (GM), and cerebrospinal fluid (CSF) are important in neuroradiological applications. Quantitative Mri (qMRI) allows segmentation based on physical tissue properties, and the dependencies on MR scanner settings are removed. Brain tissue groups into clusters in the three dimensional space formed by the qMRI parameters R1, R2 and PD, and partial volume voxels are intermediate in this space. The qMRI parameters, however, depend on the main magnetic field strength. Therefore, longitudinal studies can be seriously limited by system upgrades. The aim of this work was to apply one recently described brain tissue segmentation method, based on qMRI, at both 1.5 T and 3.0 T field strengths, and to investigate similarities and differences.

Methods

In vivo qMRI measurements were performed on 10 healthy subjects using both 1.5 T and 3.0 T MR scanners. The brain tissue segmentation method was applied for both 1.5 T and 3.0 T and volumes of WM, GM, CSF and brain parenchymal fraction (BPF) were calculated on both field strengths. Repeatability was calculated for each scanner and a General Linear Model was used to examine the effect of field strength. Voxel-wise t-tests were also performed to evaluate regional differences.

Results

Statistically significant differences were found between 1.5 T and 3.0 T for WM, GM, CSF and BPF (p<0.001). Analyses of main effects showed that WM was underestimated, while GM and CSF were overestimated on 1.5 T compared to 3.0 T. The mean differences between 1.5 T and 3.0 T were -66 mL WM, 40 mL GM, 29 mL CSF and -1.99% BPF. Voxel-wise t-tests revealed regional differences of WM and GM in deep brain structures, cerebellum and brain stem.

Conclusions

Most of the brain was identically classified at the two field strengths, although some regional differences were observed.

Place, publisher, year, edition, pages
United States: Public Library of Science, 2013
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-97960 (URN)10.1371/journal.pone.0074795 (DOI)000324494000135 ()
Available from: 2013-09-23 Created: 2013-09-23 Last updated: 2017-12-06
Warntjes, M., Tisell, A., Blystad, I., Landtblom, A.-M., Engström, M. & Lundberg, P. (2013). Normalized Quantitative Magnetic Resonance Imaging on Multiple Sclerosis. In: : . Paper presented at International Society for Magnetic Resonance in Medicine (ISMRM), Salt Lake City 2013.
Open this publication in new window or tab >>Normalized Quantitative Magnetic Resonance Imaging on Multiple Sclerosis
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2013 (English)Conference paper, Poster (with or without abstract) (Other academic)
National Category
Other Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-114871 (URN)
Conference
International Society for Magnetic Resonance in Medicine (ISMRM), Salt Lake City 2013
Available from: 2015-03-05 Created: 2015-03-05 Last updated: 2016-02-19
West, J., Blystad, I., Engström, M., Warntjes, M. J. & Lundberg, P. (2013). On fully automated whole-brain tissue segementation at 1.5 T and 3 T based on quantitative MRI.. In: : . Paper presented at International Society for Magnetic Resonance in Medicine (ISMRM-MS 2013), London, UK.
Open this publication in new window or tab >>On fully automated whole-brain tissue segementation at 1.5 T and 3 T based on quantitative MRI.
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2013 (English)Conference paper, Poster (with or without abstract) (Other academic)
National Category
Other Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-114874 (URN)
Conference
International Society for Magnetic Resonance in Medicine (ISMRM-MS 2013), London, UK
Available from: 2015-03-05 Created: 2015-03-05 Last updated: 2017-11-16
West, J., Blystad, I., Engström, M., Warntjes, M. J. & Lundberg, P. (2013). QMRI of normal appearing white matter in MS patients with normal MR imaging brain scans. In: : . Paper presented at European Society for Magnetic Resonance in Medicine and Biology (ESMRMB 2013), Toulouse, France.
Open this publication in new window or tab >>QMRI of normal appearing white matter in MS patients with normal MR imaging brain scans
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2013 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-114870 (URN)
Conference
European Society for Magnetic Resonance in Medicine and Biology (ESMRMB 2013), Toulouse, France
Available from: 2015-03-05 Created: 2015-03-05 Last updated: 2016-02-19
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8857-5698

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