| 1. |
- Al-Amiry, Bariq, 1976-, et al.
(author)
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Does body mass index affect restoration of femoral offset, leg length and cup positioning after total hip arthroplasty? : a prospective cohort study
- 2019
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In: BMC Musculoskeletal Disorders. - : BioMed Central (BMC). - 1471-2474. ; 20
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Journal article (peer-reviewed)abstract
- Background: In obese patients, total hip arthroplasty (THA) can be technically demanding with increased perioperative risks. The aim of this prospective cohort study is to evaluate the effect of body mass index (BMI) on radiological restoration of femoral offset (FO) and leg length as well as acetabular cup positioning.Methods: In this prospective study, patients with unilateral primary osteoarthritis (OA) treated with THA between September 2010 and December 2013 were considered for inclusion. The perioperative plain radiographs were standardised and used to measure the preoperative degree of hip osteoarthritis, postoperative FO, leg length discrepancy (LLD), acetabular component inclination and anteversion.Results: We included 213 patients (74.5% of those considered for inclusion) with a mean BMI of 27.7 (SD 4.5) in the final analysis. The postoperative FO was improper in 55% and the LLD in 15%, while the cup inclination and anteversion were improper in 13 and 23% of patients respectively. A multivariable logistic regression model identified BMI as the only factor that affected LLD. Increased BMI increased the risk of LLD (OR 1.14, 95% CI 1.04 to 1.25). No other factors included in the model affected any of the primary or secondary outcomes.Conclusion: Increased BMI showed a negative effect on restoration of post-THA leg length but not on restoration of FO or positioning of the acetabular cup. Age, gender, OA duration or radiological severity and surgeon’s experience showed no relation to post-THA restoration of FO, leg length or cup positioning.
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| 2. |
- Al-Amiry, Bariq, 1976-
(author)
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Radiological measurements in total hip arthroplasty
- 2018
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Doctoral thesis (other academic/artistic)abstract
- Every year, about 1 million patients worldwide and 20000 patients in Sweden undergo total hip arthroplasty (THA). This type of operation is considered a successful, safe and cost-effective procedure to regain mobility and restore hip joint function in patients suffering from severe hip joint disease or trauma. The main goals of the operation are to relief the pain, improve quality of life (QoL) and to restore the biomechanical forces around the hip with appropriate femoral offset (FO), leg length and proper component position and orientation. The radiographic preoperative planning and postoperative evaluation of these parameters require good validity, interobserver reliability and intraobserver reproducibility. Most patients are satisfied after THA, although this treatment still has its complications. About 10 % of THA patients report persistent pain and suboptimal functional outcome and QoL at long-term follow-up. The absolute number of dissatisfied patients is expected to rise given the increase in the annual number of THA performed. Therefore, every effort should be made to investigate factors that possibly influence THA outcome. The data available about the influence of preoperative radiological severity and symptom duration of OA on the outcome of THA are scarce and contradictory. Further studies even needed to evaluate the effect of obesity on post-operative THA radiological measurements
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| 3. |
- Al-Amiry, Bariq Sh. 1976-, et al.
(author)
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The Influence of Radiological Severity and Symptom Duration of Osteoarthritis on Postoperative Outcome After Total Hip Arthroplasty : A Prospective Cohort Study
- 2018
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In: The Journal of Arthroplasty. - : CHURCHILL LIVINGSTONE INC MEDICAL PUBLISHERS. - 0883-5403 .- 1532-8406. ; 33:2, s. 436-440
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Journal article (peer-reviewed)abstract
- Background: We aimed to investigate the influence of preoperative radiological severity and symptom duration of hip osteoarthritis (OA) on the postoperative functional outcome, quality of life, as well as abductor muscle strength after total hip arthroplasty (THA). Methods: In this prospective cohort study, we studied 250 patients. Preoperatively, we evaluated the function with the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and quality of life with euroqol-5D (EQ-5D). At 1 year after THA, the same scores and also hip abductor muscle strength were measured in 222 patients. We divided the cohort twice, first according to the radiological OA severity [Kellgren-Lawrence classification (KL)] and then according to the OA symptom duration. We investigated whether the preoperative KL class and symptom duration influenced the 1-year WOMAC (primary outcome measure) or EQ-5D and abductor muscle strength (secondary outcome measures). Results: The crude results showed that KL class and symptom duration had no influence (P = .90 and P = .20, respectively) on the 1-yearWOMAC. Younger age, male gender, and lower body mass index were associated with a better function. Regarding 1-year EQ-5D, the crude results showed that body mass index and KL class had no influence (P = .83 and P = .39, respectively). The adjusted results showed that only age and gender influenced the postoperative EQ-5D. No influence of the tested factors was found on the 1-year abductor muscle strength. Conclusion: Preoperative radiological OA severity and symptom duration had no influence on the outcome of THA and should probably not affect the decision about timing the operative intervention.
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| 4. |
- Barrefelt, Asa, et al.
(author)
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Fluorescence labeled microbubbles for multimodal imaging
- 2015
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In: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 464:3, s. 737-742
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Journal article (peer-reviewed)abstract
- Air-filled polyvinyl alcohol microbubbles (PVA-MBs) were recently introduced as a contrast agent for ultrasound imaging. In the present study, we explore the possibility of extending their application in multimodal imaging by labeling them with a near infrared (NIR) fluorophore, VivoTag-680. PVA-MBs were injected intravenously into FVB/N female mice and their dynamic biodistribution over 24 h was determined by 3D-fluorescence imaging co-registered with 3D-mu CT imaging, to verify the anatomic location. To further confirm the biodistribution results from in vivo imaging, organs were removed and examined histologically using bright field and fluorescence microscopy. Fluorescence imaging detected PVA-MB accumulation in the lungs within the first 30 min post-injection. Redistribution to a low extent was observed in liver and kidneys at 4 h, and to a high extent mainly in the liver and spleen at 24 h. Histology confirmed PVA-MB localization in lung capillaries and macrophages. In the liver, they were associated with Kupffer cells; in the spleen, they were located mostly within the marginal-zone. Occasional MBs were observed in the kidney glomeruli and interstitium. The potential application of PVA-MBs as a contrast agent was also studied using ultrasound (US) imaging in subcutaneous and orthotopic pancreatic cancer mouse models, to visualize blood flow within the tumor mass. In conclusion, this study showed that PVA-MBs are useful as a contrast agent for multimodal imaging. (C) 2015 Elsevier Inc. All rights reserved.
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| 5. |
- Barrefelt, Åsa, et al.
(author)
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Biodistribution, kinetics, and biological fate of SPION microbubbles in the rat
- 2013
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In: International Journal of Nanomedicine. - 1176-9114 .- 1178-2013. ; 8, s. 3241-3254
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Journal article (peer-reviewed)abstract
- Background: In the present investigation, we studied the kinetics and biodistribution of a contrast agent consisting of poly(vinyl alcohol) (PVA) microbubbles containing superparamagnetic iron oxide (SPION) trapped between the PVA layers (SPION microbubbles). Methods: The biological fate of SPION microbubbles was determined in Sprague-Dawley rats after intravenous administration. Biodistribution and elimination of the microbubbles were studied in rats using magnetic resonance imaging for a period of 6 weeks. The rats were sacrificed and perfusion-fixated at different time points. The magnetic resonance imaging results obtained were compared with histopathologic findings in different organs. Results: SPION microbubbles could be detected in the liver using magnetic resonance imaging as early as 10 minutes post injection. The maximum signal was detected between 24 hours and one week post injection. Histopathology showed the presence of clustered SPION microbubbles predominantly in the lungs from the first time point investigated (10 minutes). The frequency of microbubbles declined in the pulmonary vasculature and increased in pulmonary, hepatic, and splenic macrophages over time, resulting in a relative shift from the lungs to the spleen and liver. Meanwhile, macrophages showed increasing signs of cytoplasmic iron accumulation, initially in the lungs, then followed by other organs. Conclusion: The present investigation highlights the biological behavior of SPION microbubbles, including organ distribution over time and indications for biodegradation. The present results are essential for developing SPION microbubbles as a potential contrast agent and/or a drug delivery vehicle for specific organs. Such a vehicle will facilitate the use of multimodality imaging techniques, including ultrasound, magnetic resonance imaging, and single positron emission computed tomography, and hence improve diagnostics, therapy, and the ability to monitor the efficacy of treatment.
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| 6. |
- Barrefelt, Åsa, et al.
(author)
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DYNAMIC MR IMAGING, BIODISTRIBUTION AND PHARMACOKINETICS OF POLYMER SHELLED MICROBUBBLES CONTAINING SPION
- 2014
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In: NANO. - 1793-2920. ; 9:6, s. 1450069-
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Journal article (peer-reviewed)abstract
- Magnetic Resonance Imaging (MRI) is a noninvasive diagnostic method that provides information on morphological and physiological changes of the internal organs over time. Imaging and measurements can be repeated on the same subject, thereby reducing inter-individual variability effects and hence the number of subjects required. A potential MRI contrast agent consisting of microbubbles embedded with superparamagnetic iron oxide nanoparticles (SPION) in the shell (SPION MBs) was injected intravenously into rats to determine their biodistribution and pharmacokinetics using MR imaging. Agarose phantoms containing SPION MBs were scanned using 3 T MRI to construct a standard curve. Rats were injected with SPION MBs, free SPION or plain MBs and scanned dynamically at 3 T using a clinical MR scanner. The relaxation rate (R2*) was studied over time as a measure of the iron oxide concentrations to enable calculation of the pharmacokinetic parameters. The kinetics of SPION MBs in the liver was fitted to a one-compartment model. Furthermore, the biological fate of SPION MBs was examined via a histological survey of tissue samples using Perls' Prussian blue staining and immunohistochemistry (IHC). 1.2 h after injection of SPION MBs, T2* of the liver had decreased to its minimum. The elimination half-life of SPION MBs was 598.2 +/- 97.3 h, while the half-life for SPION was 222.6 +/- 26.4 h. Moreover, our study showed that SPION MBs were taken up by the macrophages in the lungs, spleen and liver. MBs labeled with SPION can be used for MR imaging. Moreover, MRI is a reliable and noninvasive tool that can be utilized in pharmacokinetic investigations of future contrast agents using SPION MBs and SPION in the rat.
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| 7. |
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| 8. |
- Brismar, Torkel B
(author)
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Assessment of skeletal structure by MR relaxometry
- 1999
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Doctoral thesis (other academic/artistic)abstract
- Introduction: More than 40 per cent of all women older than 50 years will suffer from a hip, wrist or vertebral fracture. Most of these fractures are related to bone fragility, osteoporosis. If the disease is diagnosed and treated at an early stage the risk of fracture can be decreased. Traditional methods in clinical use primarily use the absorption of X-ray energy to evaluate bone quality. However, these methods do not evaluate the micro-structure of the bone, which has a major influence on biomechanical strength. This thesis evaluates a method to study the micro structure of trabecular bone by magnetic resonance (MR) relaxometry. Methods: Magnetic inhomogeneity arise at the interface between trabecular bone and bone marrow. The magnetic inhomogeneity results in decreased signal intensity in gradient echo images. The rate of the signal decrease can be used as an indirect measure of the trabecular bone structure called R2* (= 1/T2*). The trabecular bone is embedded in bone marrow containing fat and water. To evaluate the influence of fat and water content on T2* measurements the signal behaviour as a function of TE was studied in porcine lumbar vertebrae and fat emulsions. T2* values were related to biomechanical strength tested experimentally. A new method to study trabecular bone orientation by MR relaxometry was developed. MR relaxometric values of human vertebrae were related to the amount of bone mineral in vitro. The obtained MR relaxometric values of spine, hip and calcaneus were related to values obtained by dual X-ray absorptiometry (DXA) and by quantitative ultrasound QUS). Results: There was a relationship between fat content and T2*. As fat and water have different spin-lattice relaxation times (Tl) TR will theoretically also affect T2* measurements. The sagittal imaging plane is advantageous when performing MR relaxometry of the spine. Under experimental conditions MR relaxometry can predict biomechanical strength. Trabecular bone orientation studied by MR relaxometry in vitro can be calculated by rotation of the studied object in three orientations orthogonal to the external magnetic field. A relationship between results obtained by MR relaxometry and by bone mineral absorptiometry measurements was observed in vitro. Also in vivo MR relaxometry was related to absorptiometry of hip and to QUS of calcaneus. Conclusion: MR relaxometry is an accurate method to evaluate trabecular bone structure in vivo. The technique will be of interest not only for research purposes, but also for diagnosis and for treatment control at various diseases affecting the skeleton.
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| 9. |
- Brismar, Torkel B., et al.
(author)
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Magnetite Nanoparticles Can Be Coupled to Microbubbles to Support Multimodal Imaging
- 2012
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In: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 13:5, s. 1390-1399
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Journal article (peer-reviewed)abstract
- Microbubbles (MBs) are commonly used as injectable ultrasound contrast agent (UCA) in modern ultrasonography. Polymer-shelled UCAs present additional potentialities with respect to marketed lipid-shelled UCAs. They are more robust; that is, they have longer shelf and circulation life, and surface modifications are quite easily accomplished to obtain enhanced targeting and local drug delivery. The next generation of UCAs will be required to support not only ultrasound-based imaging methods but also other complementary diagnostic approaches such as magnetic resonance imaging or computer tomography. This work addresses the features of MBs that could function as contrast agents for both ultrasound and magnetic resonance imaging. The results indicate that the introduction of iron oxide nanoparticles (SPIONs) in the poly(vinyl alcohol) shell or on the external surface of the MBs does not greatly decrease the echogenicity of the host MBs compared with the unmodified one. The presence of SPIONs provides enough magnetic susceptibility to the MBs to accomplish good detectability both in vitro and in vivo. The distribution of SPIONs on the shell and their aggregation state seem to be key factors for the optimization of the transverse relaxation rate.
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| 10. |
- Brismar, Torkel, et al.
(author)
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Liver Vessel Enhancement by Gd-BOPTA and Gc-EOB-DTPA – a Comparison in Healthy Volunteers.
- 2009
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In: Acta Radiologica. - : Informa Healthcare. - 0284-1851 .- 1600-0455. ; 50:7, s. 709-715
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Journal article (peer-reviewed)abstract
- Background: A thorough understanding of magnetic resonance (MR) contrast media dynamics makes it possible to choose the optimal contrast media for each investigation. Differences in visualizing hepatobiliary function between Gd-BOPTA and Gd-EOB-DTPA have previously been demonstrated, but less has been published regarding differences in liver vessel visualization.Purpose: To compare the liver vessel and liver parenchymal enhancement dynamics of Gd-BOPTA (MultiHance®) and Gd-EOB-DTPA (Primovist®). Material and Methods: The signal intensity of the liver parenchyma, the common hepatic artery, the middle hepatic vein, and a segmental branch of the right portal vein, was obtained in 10 healthy volunteers before contrast media administration, during arterial and portal venous phases, and 10, 20, 30, 40 and 130 minutes after intravenous contrast medium injection, but due to scanner limitations not during the hepatic venous phase. Results: Maximum enhancement of liver parenchyma was observed from the portal venous phase until 130 minutes after Gd-BOPTA administration and from 10 minutes to 40 minutes after Gd-EOB-DTPA. There was no difference in maximum enhancement of liver parenchyma between the two contrast media. When using Gd-BOPTA, the vascular contrast enhancement was still apparent 40 minutes after injection, but had vanished 10 minutes after Gd-EOB-DTPA injection. The maximum difference in signal intensity between the vessels and the liver parenchyma was significantly greater with Gd-BOPTA than with Gd-EOB-DTPA (p<0.0001). Conclusion: At the dosage used in this study Gd-BOPTA yields higher maximum enhancement of the hepatic artery, portal vein and middle hepatic vein during the arterial and the portal venous phase and during the delayed phases than Gd-EOB-DTPA does, whereas there is no difference in liver parenchymal enhancement between the two contrast agents.
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