umu.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Grönlund, Christer
Publications (10 of 31) Show all publications
Lindkvist, M. & Grönlund, C. (2015). Absolute quantifications of oxy- and deoxyhemoglobin concentrations by combination of differentially resolved spectroscopy and spatially resolved spectroscopy [Letter to the editor]. Spectroscopy Letters, 48(3), 170-172
Open this publication in new window or tab >>Absolute quantifications of oxy- and deoxyhemoglobin concentrations by combination of differentially resolved spectroscopy and spatially resolved spectroscopy
2015 (English)In: Spectroscopy Letters, ISSN 0038-7010, E-ISSN 1532-2289, Vol. 48, no 3, p. 170-172Article in journal, Letter (Refereed) Published
Abstract [en]

This letter proposes a theoretical framework to calculate absolute concentrations of oxy- and deoxyhemoglobin using continuous-wave near-infrared spectroscopy. While previous methods on this topic require assumptions on constant blood volume, the proposed method does not. Equations for the absolute concentrations were derived from a combination of the modified Beer-Lambert equation and the theory of diffusion of photons in turbid media. The method has an advantage over and is theoretically consistent with previous methods. It needs yet to be evaluated in an experimental study.

Place, publisher, year, edition, pages
Taylor & Francis, 2015
Keyword
NIRS, absolute quantification, differential spectroscopy, spatially resolved spectroscopy
National Category
Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:umu:diva-96484 (URN)10.1080/00387010.2013.867887 (DOI)000343807900003 ()
Available from: 2014-12-01 Created: 2014-11-21 Last updated: 2018-03-15Bibliographically approved
Ibrahimi, P., Jashari, F., Johansson, E., Grönlund, C., Bajraktari, G., Wester, P. & Henein, M. Y. (2015). Common carotid intima-media features determine distal disease phenotype and vulnerability in asymptomatic patients. International Journal of Cardiology, 196, 22-28
Open this publication in new window or tab >>Common carotid intima-media features determine distal disease phenotype and vulnerability in asymptomatic patients
Show others...
2015 (English)In: International Journal of Cardiology, ISSN 0167-5273, E-ISSN 1874-1754, Vol. 196, p. 22-28Article in journal (Refereed) Published
Abstract [en]

Objectives: There is a growing awareness of the importance of carotid plaque features evaluation in stroke prediction. Carotid intima-media thickness (IMT) and recently its echogenicity were used for stroke prediction, although their clinical relevance was not well determined. The aim of this study was to assess the relationship between common carotid artery (CCA) ultrasound markers of atherosclerosis and distal, bifurcation and internal carotid artery (ICA), plaque features. Methods: We analyzed 137 carotid arteries in 87 asymptomatic patients with known carotid disease (mean age 69 +/- 6 year, 34.5% females). Intima media thickness (IMT) and its gray scale median (IM-GSM) were measured at the CCA. Plaque textural features including gray scale median (GSM), juxtaluminal black area (JBA-mm(2)) without a visible cap, and plaque coarseness, at bifurcation and ICA were also determined. CCA measurements were correlated with those of the distal plaques. Results: An increased IMT in CCA correlated with plaque irregularities in the bifurcation and ICA (r = 0.53, p < 0.001), while IM-GSM was closely related to plaque echogenicity (GSM) (r = 0.76, p < 0.001), and other textural plaque features. Both, IMT and IM-GSM correlated weakly with stenosis severity (r = 0.27, p = 0.001 and r = -0.18, p = 0.026) respectively. Conclusion: In asymptomatic patients, measurements of CCA reflect distal, bifurcation and ICA disease, with IMT reflecting plaque irregularities and IM-GSM as markers of textural plaque abnormalities. Integrating measurements of both IMT and IM-GSM in a model could be used as a better marker of disease vulnerability over and above each measure individually. 

Keyword
Carotid atherosclerosis, Intima-media thickness, Intima-media-gray scale median, Plaque features, aque vulnerability
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-107150 (URN)10.1016/j.ijcard.2015.05.168 (DOI)000358314300005 ()26070179 (PubMedID)
Available from: 2015-09-02 Created: 2015-08-19 Last updated: 2017-12-04Bibliographically approved
Lindqvist, G., Grönlund, C., Söderberg, S., Gonzalez, M., Henein, M. Y. & Tossavainen, E. (2014). Biventricular dysfunction and their consequences predict mortality in pulmonary arterial hypertension. Paper presented at Congress of the European-Society-of-Cardiology (ESC), AUG 30-SEP 03, 2014, Barcelona, SPAIN. European Heart Journal, 35(Supplement 1, Meeting abstract P492), 78-78
Open this publication in new window or tab >>Biventricular dysfunction and their consequences predict mortality in pulmonary arterial hypertension
Show others...
2014 (English)In: European Heart Journal, ISSN 0195-668X, E-ISSN 1522-9645, Vol. 35, no Supplement 1, Meeting abstract P492, p. 78-78Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
Oxford University Press, 2014
National Category
Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:umu:diva-97246 (URN)000343001300287 ()
Conference
Congress of the European-Society-of-Cardiology (ESC), AUG 30-SEP 03, 2014, Barcelona, SPAIN
Available from: 2014-12-15 Created: 2014-12-12 Last updated: 2018-03-15Bibliographically approved
Gustafsson, S., Granåsen, G., Wiklund, U., Grönlund, C., Suhr, O. B. & Lindqvist, P. (2014). Discriminating hereditary transthyretin cardiomyopathy from hypertrophic cardiomyopathy using an echocardiographic and ECG based classification tree. Paper presented at Congress of the European-Society-of-Cardiology (ESC), AUG 30-SEP 03, 2014, Barcelona, SPAIN. European Heart Journal, 35(Supplement 1, Meeting abstract P5254), 929-929
Open this publication in new window or tab >>Discriminating hereditary transthyretin cardiomyopathy from hypertrophic cardiomyopathy using an echocardiographic and ECG based classification tree
Show others...
2014 (English)In: European Heart Journal, ISSN 0195-668X, E-ISSN 1522-9645, Vol. 35, no Supplement 1, Meeting abstract P5254, p. 929-929Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
Oxford University Press, 2014
National Category
Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:umu:diva-97261 (URN)000343001305297 ()
Conference
Congress of the European-Society-of-Cardiology (ESC), AUG 30-SEP 03, 2014, Barcelona, SPAIN
Available from: 2014-12-15 Created: 2014-12-12 Last updated: 2017-12-05Bibliographically approved
Ibrahimi, P., Jashari, F., Johansson, E., Grönlund, C., Bajraktari, G., Wester, P. & Henein, M. Y. (2014). Vulnerable plaques in the contralateral carotid arteries in symptomatic patients: a detailed ultrasound analysis. Atherosclerosis, 235(2), 526-531
Open this publication in new window or tab >>Vulnerable plaques in the contralateral carotid arteries in symptomatic patients: a detailed ultrasound analysis
Show others...
2014 (English)In: Atherosclerosis, ISSN 0021-9150, E-ISSN 1879-1484, Vol. 235, no 2, p. 526-531Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND AIM: Carotid plaques may represent a generalized atherosclerotic syndrome or a localized disease. The aim of this study was to assess the morphological and textural features of carotid plaques located contralateral to the symptomatic side and compare them with the symptomatic side and with plaques from asymptomatic patients. METHODS: We studied 66 arteries in 39 patients (mean age 70 ± 7 year, 33% females). Arterial plaques were classified as either symptomatic (n = 30), contralateral to symptomatic (n = 25) or asymptomatic (n = 11). We compared several plaque features between these groups including the mean values of the grey scale median (GSM), entropy, juxtaluminal black area (JBA) without visible echogenic cap, GSM of the JBA and surface irregularity. RESULTS: The plaques contralateral to symptomatic arteries had similar morphological and textural features to those in the symptomatic arteries. In contrast, they had more vulnerable morphological and textural features than those in asymptomatic arteries: less smooth plaques (12% vs. 55%) and instead more often mildly irregular (60% vs 36%) or markedly irregular (28% vs. 9%; p = 0.03), lower GSM (26.2 ± 8 vs. 49.4 ± 14, p < 0.001) and lower GSM of the JBA (5.0 ± 3.6 vs. 11.4 ± 2.1, p = 0.008). The frequency of entropy and plaque calcification was similar in all groups. CONCLUSION: Symptomatic patients with carotid artery disease seem to have similar morphological and textural features of vulnerability in the symptomatic and the contralateral carotid arteries, which are profound compared with asymptomatic carotid arteries. These findings support the concept of generalized carotid atherosclerotic pathology rather than incidental unilateral disease, and also emphasize a need for aggressive measures for plaque stabilization, particularly in symptomatic patients.

Place, publisher, year, edition, pages
Elsevier, 2014
Keyword
carotid artery disease, plaque vulnerability, gray scale median, juxtaluminal black area
National Category
Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:umu:diva-93540 (URN)10.1016/j.atherosclerosis.2014.05.934 (DOI)000342411000941 ()24953493 (PubMedID)
Available from: 2014-09-24 Created: 2014-09-24 Last updated: 2017-12-05Bibliographically approved
Lindberg, F., Öhberg, F., Brodin, L. & Grönlund, C. (2013). Assessment of intramuscular activation patterns using ultrasound M-mode strain. Journal of Electromyography & Kinesiology, 23(4), 879-885
Open this publication in new window or tab >>Assessment of intramuscular activation patterns using ultrasound M-mode strain
2013 (English)In: Journal of Electromyography & Kinesiology, ISSN 1050-6411, E-ISSN 1873-5711, Vol. 23, no 4, p. 879-885Article in journal (Refereed) Published
Abstract [en]

The intramuscular activation pattern can be connected to the motor unit recruitment strategy of force generation and fatigue resistance. Electromyography has earlier been used in several studies to quantify the spatial inhomogeneity of the muscle activation. We applied ultrasound M-mode strain to study the activation pattern through the tissue deformation. Correlation values of the strain at different force levels were used to quantify the spatial changes in the activation. The assessment was done including the biceps brachii muscle of 8 healthy subjects performing isometric elbow flexion contractions ranging from 0% to 80% of maximum voluntary contraction. The obtained results were repeatable and demonstrated consistent changes of the correlation values during force regulation, in agreement with previously presented EMG-results. Both intra-subject and inter-subject activation patterns of strain were considered along and transverse the fiber direction. The results suggest that ultrasound M-mode strain can be used as a complementary method to study intramuscular activation patterns with high spatial resolution.

(C) 2013 Elsevier Ltd. All rights reserved.

Keyword
Intramuscular activation, Recruitment strategies, Ultrasound, Strain, Biceps brachii
National Category
Neurology Neurosciences Physiology Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-79242 (URN)10.1016/j.jelekin.2013.02.011 (DOI)000321107900019 ()
Available from: 2013-09-05 Created: 2013-08-13 Last updated: 2018-01-11Bibliographically approved
Gustafsson, S., Grönlund, C., Mörner, S., Suhr, O. & Lindqvist, P. (2013). Can echocardiography differentiate hereditary transthyretin amyloidosis from hypertrophic cardiomyopathy?. Paper presented at Congress of the European-Society-of-Cardiology (ESC), AUG 31-SEP 04, 2013, Amsterdam, NETHERLANDS. European Heart Journal, 34(Supplement: 1), 213-213
Open this publication in new window or tab >>Can echocardiography differentiate hereditary transthyretin amyloidosis from hypertrophic cardiomyopathy?
Show others...
2013 (English)In: European Heart Journal, ISSN 0195-668X, E-ISSN 1522-9645, Vol. 34, no Supplement: 1, p. 213-213Article in journal, Meeting abstract (Other academic) Published
Abstract [en]

Purpose: Hereditary transthyretin amyloidosis (ATTR) andhypertrophic cardiomyopathy (HCM) have many phenotypic similarities when examined by echocardiography. As the two conditions have different treatment strategies it is of importance to accurately diagnose these patients early in the disease. This study aimed to identify the most accurate echocardiographic method in differentiating these two conditions by using traditional and speckle tracking echocardiographyas well as myocardial texture analysis.

Methods: We investigated 40 healthy controls, 33 patients with biopsy proven ATTR and 20 with HCM. All patients had septal thickness >12 mm. We measured left ventricular (LV) global strain as intrinsic systolic function and LV E/e' to estimate filling pressures. We also tested septal cyclic integrated backscatter (cIBS) and septal entropy as both being measures for myocardial highly reflection pattern whereas cIBS showing motion of highly reflective echoes and entropy the distribution of highly reflective echoes.

Results: LV global strain, cIBS and E/e' were not useful in differentiating ATTR from HCM. However, septal entropy was found to be significantly different and showed an area under the curve from ROC analysis of 0.66 separating ATTR from HCM.

Conclusion: After using detailed analysis of different aspects of LV morphology and function we found that myocardial texture behavior from entropy analysis was the only method useful in differentiating patients with ATTR fromHCM.

Place, publisher, year, edition, pages
Oxford University Press, 2013
National Category
Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:umu:diva-85325 (URN)10.1093/eurheartj/eht308.P1195 (DOI)000327744601221 ()
Conference
Congress of the European-Society-of-Cardiology (ESC), AUG 31-SEP 04, 2013, Amsterdam, NETHERLANDS
Available from: 2014-02-04 Created: 2014-01-31 Last updated: 2017-12-06Bibliographically approved
Lindkvist, M., Granåsen, G. & Grönlund, C. (2013). Coherent Derivation of Equations for Differential Spectroscopy and Spatially Resolved Spectroscopy: An undergraduate tutorial. Spectroscopy Letters, 46(4), 243-249
Open this publication in new window or tab >>Coherent Derivation of Equations for Differential Spectroscopy and Spatially Resolved Spectroscopy: An undergraduate tutorial
2013 (English)In: Spectroscopy Letters, ISSN 0038-7010, E-ISSN 1532-2289, Vol. 46, no 4, p. 243-249Article in journal (Refereed) Published
Abstract [en]

Near-infrared spectroscopy (NIRS) is a spectroscopic method that is frequently used in health care and sports medicine to monitor oxygenation parameters in biological tissue. This tutorial provides a coherent derivation of equations for differential spectroscopy and spatially resolved spectroscopy, from basic theories to implementable equations. The basic theories are applicable to any kind of tissue oximeter but mainly focus on continuous-wave instruments. 

Place, publisher, year, edition, pages
Taylor & Francis, 2013
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:umu:diva-79133 (URN)10.1080/00387010.2012.728158 (DOI)000316657900001 ()
Available from: 2013-08-08 Created: 2013-08-08 Last updated: 2017-12-06Bibliographically approved
Lindberg, F., Mårtensson, M., Grönlund, C. & Brodin, L.-Å. (2013). Evaluation of ultrasound Tissue Velocity Imaging: a phantom study of velocity estimation in skeletal muscle low-level contractions. BMC Medical Imaging, 13(16)
Open this publication in new window or tab >>Evaluation of ultrasound Tissue Velocity Imaging: a phantom study of velocity estimation in skeletal muscle low-level contractions
2013 (English)In: BMC Medical Imaging, ISSN 1471-2342, E-ISSN 1471-2342, Vol. 13, no 16Article in journal (Refereed) Published
Abstract [en]

Background: Tissue Velocity Imaging (TVI) is an ultrasound based technique used for quantitative analysis of the cardiac function and has earlier been evaluated according to myocardial velocities. Recent years several studies have reported applying TVI in the analysis of skeletal muscles. Skeletal tissue velocities can be very low. In particular, when performing isometric contractions or contractions of low force level the velocities may be much lower compared to the myocardial tissue velocities. Methods: In this study TVI was evaluated for estimation of tissue velocities below the typical myocardial velocities. An in-house phantom was used to see how different PRF-settings affected the accuracy of the velocity estimations. Results: With phantom peak velocity at 0.03 cm/s the error ranged from 31% up to 313% with the different PRF-settings in this study. For the peak velocities at 0.17 cm/s and 0.26 cm/s there was no difference in error with tested PFR settings, it is kept approximately around 20%. Conclusions: The results from the present study showed that the PRF setting did not seem to affect the accuracy of the velocity estimation at tissue velocities above 0.17 cm/s. However at lower velocities (0.03 cm/s) the setting was crucial for the accuracy. The PRF should therefore preferable be reduced when the method is applied in low-level muscle contraction.

Keyword
Tissue Velocity Imaging, Ultrasound, Skeletal muscle, Phantom evaluation, Pulse repetition frequency
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-79055 (URN)10.1186/1471-2342-13-16 (DOI)000321369400001 ()
Available from: 2014-02-25 Created: 2013-08-06 Last updated: 2017-12-05Bibliographically approved
Grönlund, C., Claesson, K. & Holtermannz, A. (2013). Imaging two-dimensional mechanical waves of skeletal muscle contraction. Ultrasound in Medicine and Biology, 39(2), 360-369
Open this publication in new window or tab >>Imaging two-dimensional mechanical waves of skeletal muscle contraction
2013 (English)In: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 39, no 2, p. 360-369Article in journal (Refereed) Published
Abstract [en]

Skeletal muscle contraction is related to rapid mechanical shortening and thickening. Recently, specialized ultrasound systems have been applied to demonstrate and quantify transient tissue velocities and one-dimensional (1-D) propagation of mechanical waves during muscle contraction. Such waves could potentially provide novel information on musculoskeletal characteristics, function and disorders. In this work, we demonstrate two-dimensional (2-D) mechanical wave imaging following the skeletal muscle contraction. B-mode image acquisition during multiple consecutive electrostimulations, speckle-tracking and a time-stamp sorting protocol were used to obtain 1.4 kHz frame rate 2-D tissue velocity imaging of the biceps brachii muscle contraction. The results present novel information on tissue velocity profiles and mechanical wave propagation. In particular, counter-propagating compressional and shear waves in the longitudinal direction were observed in the contracting tissue (speed 2.8-4.4 m/s) and a compressional wave in the transverse direction of the non-contracting muscle tissue (1.2-1.9 m/s). In conclusion, analysing transient 2-D tissue velocity allows simultaneous assessment of both active and passive muscle tissue properties. (E-mail: christer.gronlund@vll.se) (C) 2013 World Federation for Ultrasound in Medicine & Biology.

Keyword
Ultrasound, Mechanical wave, Speckle-tracking, High frame rate, Skeletal muscle, Propagation velocity, Imaging, Electrostimulation, Compressional, Shear
National Category
Medical Image Processing Other Medical Engineering
Identifiers
urn:nbn:se:umu:diva-65907 (URN)10.1016/j.ultrasmedbio.2012.09.005 (DOI)000313207100018 ()
Available from: 2013-03-21 Created: 2013-02-13 Last updated: 2018-03-15Bibliographically approved
Organisations

Search in DiVA

Show all publications