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Norén, Bengt
Publications (10 of 20) Show all publications
Forsgren, M., Norén, B., Kihlberg, J., Dahlqvist Leinhard, O., Kechagias, S. & Lundberg, P. (2015). Comparing hepatic 2D and 3D magnetic resonance elastography methods in a clinical setting – Initial experiences. European Journal of Radiology Open, 2, 66-70
Open this publication in new window or tab >>Comparing hepatic 2D and 3D magnetic resonance elastography methods in a clinical setting – Initial experiences
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2015 (English)In: European Journal of Radiology Open, E-ISSN 2352-0477, Vol. 2, p. 66-70Article in journal (Refereed) Published
Abstract [en]

Purpose

Continuous monitoring of liver fibrosis progression in patients is not feasible with the current diagnostic golden standard (needle biopsy). Recently, magnetic resonance elastography (MRE) has emerged as a promising method for such continuous monitoring. Since there are different MRE methods that could be used in a clinical setting there is a need to investigate whether measurements produced by these MRE methods are comparable. Hence, the purpose of this pilot study was to evaluate whether the measurements of the viscoelastic properties produced by 2D (stiffness) and 3D (elasticity and ‘Gabs,Elastic’) MRE are comparable.

Materials and methods

Seven patients with diffuse or suspect diffuse liver disease were examined in the same day with the two MRE methods. 2D MRE was performed using an acoustic passive transducer, with a 1.5 T GE 450 W MR system. 3D MRE was performed using an electromagnetic active transducer, with a 1.5 T Philips Achieva MR system. Finally, mean viscoelastic values were extracted from the same anatomical region for both methods by an experienced radiologist.

Results

Stiffness correlated well with the elasticity, R2 = 0.96 (P < 0.001; slope = 1.08, intercept = 0.61 kPa), as well as with ‘Gabs,ElasticR2 = 0.96 (P < 0.001; slope = 0.95, intercept = 0.28 kPa).

Conclusion

This pilot study shows that different MRE methods can produce comparable measurements of the viscoelastic properties of the liver. The existence of such comparable measurements is important, both from a clinical as well as a research perspective, since it allows for equipment-independent monitoring of disease progression.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Liver; Rheology; Elastography; Fibrosis; MRE; MRI
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-119848 (URN)10.1016/j.ejro.2015.04.001 (DOI)
Available from: 2015-06-26 Created: 2015-06-26 Last updated: 2019-06-14Bibliographically approved
Andersson, T., Romu, T., Karlsson, A., Norén, B., Forsgren, M., Smedby, Ö., . . . Dahlqvist Leinhard, O. (2015). Consistent intensity inhomogeneity correction in water–fat MRI. Journal of Magnetic Resonance Imaging, 42(2), 468-476
Open this publication in new window or tab >>Consistent intensity inhomogeneity correction in water–fat MRI
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2015 (English)In: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 42, no 2, p. 468-476Article in journal (Refereed) Published
Abstract [en]

PURPOSE:

To quantitatively and qualitatively evaluate the water-signal performance of the consistent intensity inhomogeneity correction (CIIC) method to correct for intensity inhomogeneities METHODS: Water-fat volumes were acquired using 1.5 Tesla (T) and 3.0T symmetrically sampled 2-point Dixon three-dimensional MRI. Two datasets: (i) 10 muscle tissue regions of interest (ROIs) from 10 subjects acquired with both 1.5T and 3.0T whole-body MRI. (ii) Seven liver tissue ROIs from 36 patients imaged using 1.5T MRI at six time points after Gd-EOB-DTPA injection. The performance of CIIC was evaluated quantitatively by analyzing its impact on the dispersion and bias of the water image ROI intensities, and qualitatively using side-by-side image comparisons.

RESULTS:

CIIC significantly ( P1.5T≤2.3×10-4,P3.0T≤1.0×10-6) decreased the nonphysiological intensity variance while preserving the average intensity levels. The side-by-side comparisons showed improved intensity consistency ( Pint⁡≤10-6) while not introducing artifacts ( Part=0.024) nor changed appearances ( Papp≤10-6).

CONCLUSION:

CIIC improves the spatiotemporal intensity consistency in regions of a homogenous tissue type. J. Magn. Reson. Imaging 2014.

Place, publisher, year, edition, pages
John Wiley & Sons, 2015
Keywords
water–fat imaging;Dixon imaging;inhomogeneity correction;intensity correction;water;fat quantification
National Category
Medical Image Processing Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-112129 (URN)10.1002/jmri.24778 (DOI)000358258600026 ()25355066 (PubMedID)
Note

Funding:

Financial support from the Swedish Research Council (VR/M 2007-2884), the Research Council of Southeast Sweden (FORSS 12621), Linkoping University, Lions Research Foundation in Linkoping, Linkoping University Hospital Research Foundations and the County Council of Ostergotland is gratefully acknowledged.

Available from: 2014-11-16 Created: 2014-11-16 Last updated: 2019-06-14
Norén, B., Dahlström, N., Forsgren, M., Dahlqvist Leinhard, O., Kechagias, S., Almer, S., . . . Lundberg, P. (2015). Visual assessment of biliary excretion of Gd-EOB-DTPA in patients with suspected diffuse liver disease – a biopsy-controlled prospective study. European Journal of Radiology Open, 2, 19-25
Open this publication in new window or tab >>Visual assessment of biliary excretion of Gd-EOB-DTPA in patients with suspected diffuse liver disease – a biopsy-controlled prospective study
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2015 (English)In: European Journal of Radiology Open, ISSN 2352-0477, Vol. 2, p. 19-25Article in journal (Refereed) Published
Abstract [en]

Objectives: To qualitatively evaluate late dynamic contrast phases, 10, 20 and 30 min, after administration of Gd-EOB-DTPA with regard to biliary excretion in patients presenting with elevated liver enzymes without any clinical signs of cirrhosis or hepatic decompensation and to compare the visual assessment of contrast agent excretion with histo-pathological fibrosis stage, contrast uptake parameters and blood tests.

Methods: 29 patients were prospectively examined using 1.5-T MRI. The visually assessed presence (1) or absence (0) of contrast agent for each of five anatomical regions in randomly reviewed time-series was summarised on a four grade scale. The scores, including a total visual score, were related to the histo-pathological findings, the quantitative contrast agent uptake parameters and blood tests

Results: No relationship between the fibrosis grade or contrast uptake parameters expressed as KHep or LSC_N could be established. A negative correlation between the visual assessment and ALP was found. Comparing a sub-group of cholestatic patients with fibrosis score and Gd-EOB-DTPAdynamic parameters did not add any additional significant correlation.

Conclusions: In this prospective study with a limited number of patients we were not able to demonstrate a correlation between visually assessed biliary excretion of Gd-EOB-DTPA and  histo-pathological or contrast uptake parameters.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Gd-EOB-­DTPA, Dynamic contrast enhanced MRI, Liver, Bile, Excretion
National Category
Radiology, Nuclear Medicine and Medical Imaging Physical Chemistry
Identifiers
urn:nbn:se:liu:diva-90159 (URN)10.1016/j.ejro.2014.12.004 (DOI)
Projects
NILB
Available from: 2013-03-20 Created: 2013-03-20 Last updated: 2019-06-14Bibliographically approved
Forsgren, M., Norén, B., Kihlberg, J., Dahlqvist Leinhard, O., Kechagias, S. & Lundberg, P. (2014). Comparing 2D and 3D Magnetic Resonance Elastography Techniques in a Clinical Setting: Initial Experiences. In: : . Paper presented at ISMRM 2014, International Society for Magnetic Resonance in Medicine, 10-16 May 2014, Milan, Italy.
Open this publication in new window or tab >>Comparing 2D and 3D Magnetic Resonance Elastography Techniques in a Clinical Setting: Initial Experiences
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2014 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

Purpose: It has been shown that liver fibrosis, and even cirrhosis, may be reversible in humans. For this reason there is a great need for the imminent introduction of non-invasive and clinically useful methods in order to monitor fibrosis in patients [1, 2]. A body of evidence points to the fact that MRE is a highly useful candidate towards this end [3]. However, before using such techniques more widely, it is important to verify that comparable physical measures are provided by alternative and clinically relevant MRE approaches. The aim of this pilot study was to compare 2D and 3D MRE, also known as MR Rheology, using a commercially available 2D system, with an acoustic transducer, and 3D MRE research system, with an electromagnetic transducer, with respect to liver stiffness and elasticity in patients with diffuse or suspected diffuse liver disease. Materials and Methods: Seven patients, referred to our hospital for evaluation of elevated serum alanine aminotransferase (ALT) and/or alkaline phosphatase (ALP) levels but without signs of cirrhosis on physical examination, were recruited from a previous study [4], and examined in the course of one day. Fibrosis staging from prior biopsy were gained from [4], see Table 1. The 3D MRE method included an active electromagnetic transducer generating waves at 56 Hz, and a 1.5 T Philips Achieva MR-scanner, with a phased array body coil (Sense TorsoXL, all 16 coil elements), GRE sequence parameters include; FOV = 320x256 mm2, matrix = 80x38, slice thickness = 4 mm, # slices = 9, FA = 15°, TR = 112 ms, TE = 9.21 ms, SENSE = 2. The 2D MRE method included a passive acoustic transducer generating waves at 60 Hz, and a 1.5 T GE 450W MR-scanner, with a phased array body coil (HD8 Torso, all 8 coil elements), GRE sequence parameters include; FOV = 440x440 mm2, matrix = 256x64, slice thickness = 10 mm, # slices = 4, FA = 30°, TR = 50 ms, TE = 21.7 ms, ASSET = 2. The transducers were on both systems placed on the anterior chest wall to the right of xiphoid process (patient in a supine position), the time between each MRE acquisition was dependent on how long it took to transfer the patient between the two MR systems in the hospital (<10 min) A region of interest (ROI) was placed in an appropriate single 10 mm slice acquired using the GE MR-scanner. A corresponding ROI for the Philips system, covering the same anatomical region, was placed over three slices (4 mm thickness each). This yielded a total cranio-caudal coverage of the ROIs equal to 10 mm (on the GE data) and 12 mm (on the Philips data). The mean and standard deviations of the stiffness (GE), elasticity (Philips) and Gabs,Elastic (Philips) were calculated. Gabs,Elastic is the absolute value of the shear modulus, which in principle is equivalent to the viscoelastic property, shear stiffness. In the 3D method the shear waves were obtained by applying the curl operator and using the Voigt rheological model to obtain shear elasticity maps [5, 6]. In the 2D method the GE system provided the stiffness maps. Statistics was performed using Mathematica 9. ROI drawing and quantification of the data from the GE system was performed using Sectra PACS IDS7, and ROI drawing and quantification of the data from the Philips system was performed using a custom software package implemented in ROOT, generously provided by R. Sinkus (Kings College, London, UK). Results: The measured values are presented in Table 1. Both elasticity and Gabs,Elastic correlates well with the stiffness measurement carried out in the GE system (Fig. 1), as was shown by the elasticity and stiffness correlation R2 = 0.96 (P < 0.001) slope = 1.08 (P < 0.001), intercept = 0.61 kPa (P = 0.08), Gabs,Elastic and stiffness correlation R2 = 0.96 (P < 0.001), slope = 0.95 (P< 0.001) intercept = 0.28 kPa (P = 0.43)

National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-109079 (URN)
Conference
ISMRM 2014, International Society for Magnetic Resonance in Medicine, 10-16 May 2014, Milan, Italy
Available from: 2014-08-05 Created: 2014-08-05 Last updated: 2019-06-14
Norén, B. (2013). Non-Invasive Assessment of Liver Fibrosis with 31P-Magnetic Resonance Spectroscopy and Dynamic Contrast Enhanced Magnetic Resonance Imaging. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Non-Invasive Assessment of Liver Fibrosis with 31P-Magnetic Resonance Spectroscopy and Dynamic Contrast Enhanced Magnetic Resonance Imaging
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The present study aims at demonstrating phosphorus metabolite concentration changes and alterations in uptake/excretion of a hepatocyte specific contrast agent in patients with diffuse - or suspected diffuse - liver disease by applying two non-invasive quantitative MR techniques and to compare the results with histo-pathological findings, with focus on liver fibrosis.

In the first study phosphorus-31 MR spectroscopy using slice selection (DRESS) was implemented. Patients with histopathologically proven diffuse liver disease (n = 9) and healthy individuals (n = 12) were examined. The patients had significantly lower concentrations of phosphodiesters (PDE) and ATP compared with controls. Constructing an ‘anabolic charge’ (AC) based on absolute concentrations, [PME] / ([PME] + [PDE]), the patients had a significant larger AC than the control subjects.

The MRS technique was then, in a second study, applied on two distinct groups of patients, one group with steatosis and none-to-moderate inflammation (n = 13) and one group with severe fibrosis or cirrhosis (n = 16). A control group (n = 13) was also included. Lower concentrations of PDE and a higher AC were found in the cirrhosis group compared to the control group. Also compared to the steatosis group, the cirrhosis group had lower concentrations of PDE and a higher AC.  A significant correlation between fibrosis stage and PDE and fibrosis stage and AC was found. Using an AC cut-off value of 0.27 to discriminate between mild (stage 0-2) and advanced (stage 3-4) fibrosis yielded an AUROC value of 0.78, similar as for discriminating between F0-1 vs. F2-4.

Dynamic contrast enhanced MRI (DCE-MRI) was performed prospectively in a third study on 38 patients referred for evaluation of elevated serum alanine aminotransferase (ALT) and/or alkaline phosphatase (ALP) levels. Data were acquired from regions of interest in the liver and spleen by using single-breath-hold symmetrically sampled two-point Dixon 3D images time-series (non-enhanced, arterial and venous portal phase; 3, 10, 20 and 30 min) following a bolus injection of Gd-EOB-DTPA (0.025 mmol/kg). A new quantification procedure for calculation of the ‘hepatocyte specific uptake rate’, KHep, was applied on a two-compartment pharmacokinetic model. Liver-to-spleen contrast ratios (LSC_N) were also calculated. AUROC values of 0.71, 0.80 and 0.78, respectively, were found for KHep, LSC_N10 and LSC_N20 with regard to severe versus mild fibrosis. Significant group differences were found for KHep (borderline), LSC_N10 and LSC_N20.

In study four no significant correlation between visual assessments of bile ducts excretion of Gd-EOB-DTPA and histo-pathological grading of fibrosis or the quantified uptake of Gd-EOB-DTPA defined as KHep and LSC_N.

In conclusion 31P-MRS and DCE-MRI show promising results for achieving a non-invasive approach in discriminating different levels of fibrosis from each other.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2013. p. 72
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1351
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-90154 (URN)9789175197050 (ISBN)
Public defence
2013-03-15, Eken, Hälsouniversitetet, Campus US, Linköpings universitet, Linköping, 09:00 (Swedish)
Opponent
Supervisors
Funder
Swedish Research Council
Available from: 2013-06-04 Created: 2013-03-20 Last updated: 2017-12-18Bibliographically approved
Norén, B., Forsgren, M. F., Dahlqvist Leinhard, O., Dahlström, N., Kihlberg, J., Romu, T., . . . Lundberg, P. (2013). Separation of advanced from mild hepatic fibrosis by quantification of the hepatobiliary uptake of Gd-EOB-DTPA. European Radiology, 23(1), 174-181
Open this publication in new window or tab >>Separation of advanced from mild hepatic fibrosis by quantification of the hepatobiliary uptake of Gd-EOB-DTPA
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2013 (English)In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 23, no 1, p. 174-181Article in journal (Refereed) Published
Abstract [en]

Objectives

To apply dynamic contrast-enhanced (DCE) MRI on patients presenting with elevated liver enzymes without clinical signs of hepatic decompensation in order to quantitatively compare the hepatocyte-specific uptake of Gd-EOB-DTPA with histopathological fibrosis stage.

Methods

A total of 38 patients were prospectively examined using 1.5-T MRI. Data were acquired from regions of interest in the liver and spleen by using time series of single-breath-hold symmetrically sampled two-point Dixon 3D images (non-enhanced, arterial and venous portal phase; 3, 10, 20 and 30 min) following a bolus injection of Gd-EOB-DTPA (0.025 mmol/kg). The signal intensity (SI) values were reconstructed using a phase-sensitive technique and normalised using multiscale adaptive normalising averaging (MANA). Liver-to-spleen contrast ratios (LSC_N) and the contrast uptake rate (KHep) were calculated. Liver biopsy was performed and classified according to the Batts and Ludwig system.

Results

Area under the receiver-operating characteristic curve (AUROC) values of 0.71, 0.80 and 0.78, respectively, were found for KHep, LSC_N10 and LSC_N20 with regard to severe versus mild fibrosis. Significant group differences were found for KHep (borderline), LSC_N10 and LSC_N20.

Conclusions

Liver fibrosis stage strongly influences the hepatocyte-specific uptake of Gd-EOB-DTPA. Potentially the normalisation technique and KHep will reduce patient and system bias, yielding a robust approach to non-invasive liver function determination.

Place, publisher, year, edition, pages
Springer, 2013
Keywords
Quantification, Gd-EOB-DTPA, Dynamic contrast-enhanced MRI, Pharmacokinetics, Liver
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-87242 (URN)10.1007/s00330-012-2583-2 (DOI)000312324500022 ()
Projects
NILB
Note

Funding Agencies|Swedish Research Council|VR/M 2007-2884|Medical Research Council of South-east Sweden|FORSS 12621|Linkoping University, Linkoping University Hospital Research Foundations||County Council of Ostergotland||

Available from: 2013-01-14 Created: 2013-01-14 Last updated: 2019-06-14
Norén, B., Dahlqvist Leinhard, O., Forsgren, M., Dahlström, N., Kihlberg, J., Romu, T., . . . Lundberg, P. (2012). Prospective Evaluation of a Novel Quantification Method for the Discrimination of Mild and Severe Hepatic Fibrosis Using Gd-EOB-DTPA. In: : . Paper presented at RSNA 2012, 98th Scientific Assembly and Annual Meeting, November 25-30, 2012, Chicago, USA.
Open this publication in new window or tab >>Prospective Evaluation of a Novel Quantification Method for the Discrimination of Mild and Severe Hepatic Fibrosis Using Gd-EOB-DTPA
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2012 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-90374 (URN)
Conference
RSNA 2012, 98th Scientific Assembly and Annual Meeting, November 25-30, 2012, Chicago, USA
Available from: 2013-03-25 Created: 2013-03-25 Last updated: 2019-06-14
Norén, B., Forsgren, M., Dahlqvist Leinhard, O., Dahlström, N., Kihlberg, J., Romu, T., . . . Lundberg, P. (2012). Quantification of the hepatobiliary uptake of Gd-EOB-DTPA can separate advanced from mild fibrosis. In: : . Paper presented at ISMRM 20th Annual Meeting & Exhibition, 5-11 May, 2012, Melbourne, Australia.
Open this publication in new window or tab >>Quantification of the hepatobiliary uptake of Gd-EOB-DTPA can separate advanced from mild fibrosis
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2012 (English)Conference paper, Published paper (Other academic)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-90373 (URN)
Conference
ISMRM 20th Annual Meeting & Exhibition, 5-11 May, 2012, Melbourne, Australia
Available from: 2013-03-25 Created: 2013-03-25 Last updated: 2019-06-14
Andersson, T., Romu, T., Norén, B., Forsgren, M., Smedby, Ö., Almer, S., . . . Dahlqvist Leinhard, O. (2012). Self-calibrated DCE MRI using Multi Scale Adaptive Normalized Averaging (MANA). In: Proceedings of the annual meeting of the International Society for Magnetic Resonance in Medicine (ISMRM 2012), 2012: . Paper presented at ISMRM 2012, 20th Annual Meeting & Exhibition, 5 - 11 May 2012, Melbourne, Australia.
Open this publication in new window or tab >>Self-calibrated DCE MRI using Multi Scale Adaptive Normalized Averaging (MANA)
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2012 (English)In: Proceedings of the annual meeting of the International Society for Magnetic Resonance in Medicine (ISMRM 2012), 2012, 2012Conference paper, Published paper (Other academic)
National Category
Medical Image Processing Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-78899 (URN)
Conference
ISMRM 2012, 20th Annual Meeting & Exhibition, 5 - 11 May 2012, Melbourne, Australia
Note

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Available from: 2012-06-24 Created: 2012-06-24 Last updated: 2019-06-14
Norén, B., Forsgren, M., Dahlqvist Leinhard, O., Dahlström, N., Kihlberg, J., Romu, T., . . . Lundberg, P. (2012). Separation of advanced from mild hepatic fibrosis by quantification of the hepatobiliary uptake of Gd-EOB-DTPA. In: : . Paper presented at RSNA 2012, November 25-30, 2012, Chicago, USA.
Open this publication in new window or tab >>Separation of advanced from mild hepatic fibrosis by quantification of the hepatobiliary uptake of Gd-EOB-DTPA
Show others...
2012 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-90386 (URN)
Conference
RSNA 2012, November 25-30, 2012, Chicago, USA
Available from: 2013-03-26 Created: 2013-03-25 Last updated: 2019-06-14
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