Jutta Ellermann
University of Minnesota, CMRR - Radiology, Faculty Member
Although T2 mapping allows noninvasive evaluation of meniscus degeneration, its application at 7T requires spin echo sequences with relatively long repetition times to meet the specific absorption rate (SAR) limits which can restrict the... more
Although T2 mapping allows noninvasive evaluation of meniscus degeneration, its application at 7T requires spin echo sequences with relatively long repetition times to meet the specific absorption rate (SAR) limits which can restrict the resolution of maps. This 7T study evaluates the potential of T2* mapping for the assessment of meniscal degeneration in six patients with arthroscopically verified posterior root tears of the medial meniscus and in healthy volunteers. Increased T2* in degenerated meniscus regions suggest T2* mapping is sensitive to meniscus degeneration. T2* mapping is a promising biomarker of early meniscal degeneration which is less SAR-demanding than T2 mapping.
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In vivo cartilage imaging of the musculoskeletal system using clinical 3 T magnetic resonance imaging (MRI) systems is limited by low spatial resolution, low signal-to-noise ratio, and/or long acquisition times. Ultrahigh-field (≥7 T)... more
In vivo cartilage imaging of the musculoskeletal system using clinical 3 T magnetic resonance imaging (MRI) systems is limited by low spatial resolution, low signal-to-noise ratio, and/or long acquisition times. Ultrahigh-field (≥7 T) whole-body MRI systems have great potential to overcome these limitations and become the new standard for clinical muskuloskeletal imaging of articular cartilage. However, a number of technical challenges must first be addressed, including transmit B1 field inhomogeneities, radiofrequency heating, errors due to B0 inhomogeneities, gradients, motion, and extended examination times. In this chapter, we provide an overview of technical solutions to address these challenges and their potential benefit for articular cartilage imaging with particular attention to joints within the torso (hip and shoulder). We also highlight a number of emerging applications for articular and epiphyseal cartilage imaging that may significantly benefit from ultrahigh-field systems and the latest technical developments. Given the rapid development of MRI technology at ultrahigh field strengths and the broad potential of these systems to improve musculoskeletal imaging capabilities of cartilage, ultrahigh-field whole-body MRI is certain to play a significant role in the advancement of our understanding of articular cartilage abnormalities and the investigation of therapeutic interventions.
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Ischemic injury induced during preservation and reperfusion contributes to post-operative failure in liver transplantation. Hepatic injury and recovery from preservation was studied in an isolated rat liver model reperfused with... more
Ischemic injury induced during preservation and reperfusion contributes to post-operative failure in liver transplantation. Hepatic injury and recovery from preservation was studied in an isolated rat liver model reperfused with oxygenated erythrocytes. In order to correlate morphological and functional findings, 31-P nuclear magnetic resonance spectroscopy and electron microscopy were used to investigate metabolic and ultrastructural changes during 6 hours of reperfusion. Following cold preservation, EM's showed a primary sinusoidal cell injury, whereas the hepatocytes were well maintained. During reperfusion, hepatocytes displayed further damage. The simultaneous presence of vacuolarly degenerated mitochondria and mitochondria of increased activity was noted. 31-P NMP spectra demonstrated initially a partial ATP-recovery. The maximum level of 60% of the control ATP-value could not be further increased. EM and 31-P NMR indicate that the progressive injury to the liver is due to microcirculatory malfunction induced by an endothelial cell damage, followed by injured hepatocytes themselves, and the consequent intracellular energy crisis that is produced.
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Scanning Electron Microscopy, Magnetic Resonance Spectroscopy, Medicine, Energy Metabolism, Transplantation, and 15 morePhosphorus, Liver, Animals, Male, Organ Preservation, Ultrastructure, Clinical Sciences, Rats, Hepatocyte, Reperfusion injury, Intracellular, Mitochondrion, cell damage, Liver injury, and Reperfusion
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With the advent of ultrafast Magnetic Resonance Imaging (MRI), it is now possible to produce images with high temporal resolution. This gives the opportunity to record the passage of the paramagnetic contrast material Gadolinium-DTPA... more
With the advent of ultrafast Magnetic Resonance Imaging (MRI), it is now possible to produce images with high temporal resolution. This gives the opportunity to record the passage of the paramagnetic contrast material Gadolinium-DTPA through the tissue of the heart muscle, yielding information on regional myocardial perfusion. We assessed the accuracy of MRI to detect and quantify reductions in coronary flow secondary to stenosis in dogs and patients. Regional blood flow was measured in dogs by left atrial injection of microspheres labeled with different radioactive isotopes. Signal intensity (SI) curves were generated in regions of interest over the myocardium and the cavum of the left ventricle. A newly developed two-compartment model based on the indicator-dilution method was used for interpretation of the SI-curves. In an optimization process the free parameters of the model equation were fitted to the measured SI-curves. The following flow parameters were determined: model parameter Q*, time to peak intensity (T), maximum signal intensity (SImax) and mean transit time (MTT) as calculated from a gamma variate fit. Absolute blood flow values were calculated for the parameters MTT and Q* assuming that the intravascular volume represents 10% of the total myocardial tissue volume. Measurements were performed on a 1.5 T Magnetom SP (Siemens AG, Erlangen) using a Turbo Flash sequence (TR = 6.5 ms, TE = 3 ms, TI = 100 ms, Flip Winkel = 9 degrees). Endsystolic images (voxel size = 1.8, 2.7, 15 mm3) were taken with an 18-cm Helmholtz surface coil in the short-axis view. A Gd-DTPA bolus (0.05 mmol/kg) was injected into the left atrium of 3 anesthetized closed-chest dogs. From the myocardial SI-curves the different parameters of myocardial perfusion were compared with flow assessed by microsphere injection over a wide range of myocardial blood flows (from 0.04 ml/min/g to 7.6 ml/min/g). A third-order polynominal fit showed a good correlation for the parameter Q* and MTT, whereas T and SImax were found to have a poor correlation. The linear regression analysis for a limited range of < 2 ml/min/g showed a superior estimation of myocardial perfusion for the parameter Q* than MTT. Blood flow > 2 ml/min/g was significantly underestimated by the MRT-measurements, but the parameter Q* showed the smallest amount of the divergent changes.(ABSTRACT TRUNCATED AT 400 WORDS)
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Magnetic Resonance Imaging, Nuclear Magnetic Resonance, Nuclear medicine, Medicine, Dogs, and 15 moreHumans, Female, Animals, Male, Aged, Middle Aged, Myocardial Infarction, Adult, Blood Flow, Coronary Circulation, Organometallic Compounds, Blood Flow Velocity, Contrast Media, Myocardial Ischemia, and Cardiovascular medicine and haematology
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Following their success in numerous imaging and computer vision applications, deep-learning (DL) techniques have emerged as one of the most prominent strategies for accelerated MRI reconstruction. These methods have been shown to... more
Following their success in numerous imaging and computer vision applications, deep-learning (DL) techniques have emerged as one of the most prominent strategies for accelerated MRI reconstruction. These methods have been shown to outperform conventional regularized methods based on compressed sensing (CS). However, in most comparisons, CS is implemented with two or three hand-tuned parameters, while DL methods enjoy a plethora of advanced data science tools. In this work, we revisitℓ1-wavelet CS reconstruction using these modern tools. Using ideas such as algorithm unrolling and advanced optimization methods over large databases that DL algorithms utilize, along with conventional insights from wavelet representations and CS theory, we show thatℓ1-wavelet CS can be fine-tuned to a level close to DL reconstruction for accelerated MRI. The optimizedℓ1-wavelet CS method uses only 128 parameters compared to &gt;500,000 for DL, employs a convex reconstruction at inference time, and performs within &lt;1% of a DL approach that has been used in multiple studies in terms of quantitative quality metrics.
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Increased autophagocytosis in hepatocytes was found in response to conditions of ischaemia/hypoxia. Initial stages proved to be recordable. These were found to become manifest through the formation of phospholipid membrane structures,... more
Increased autophagocytosis in hepatocytes was found in response to conditions of ischaemia/hypoxia. Initial stages proved to be recordable. These were found to become manifest through the formation of phospholipid membrane structures, approximately 5 nm in width, coalescing in circular formations with vesicular extensions. They may further develop to form multilayer myelin structures. Enveloped cytoplasmic regions and organelles were unchanged, at the beginning, and subsequently coalesced typically into autophagolysosomes and autophagic vacuoles. Verification will be necessary to find out if these initial stages occur only in response to hypoxia or constitute a phenomenon of general validity.
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Juvenile osteochondritis dissecans (JOCD) is an orthopedic joint disorder of children and adolescents that can lead to premature osteoarthritis. Thirteen patients (mean age: 12.3 years, 4 females), 15 JOCD‐affected and five contralateral... more
Juvenile osteochondritis dissecans (JOCD) is an orthopedic joint disorder of children and adolescents that can lead to premature osteoarthritis. Thirteen patients (mean age: 12.3 years, 4 females), 15 JOCD‐affected and five contralateral healthy knees, that had a baseline and a follow‐up magnetic resonance imaging (MRI) (mean interval of 8.9 months) and were treated nonoperatively during this interval were included. Retrospectively, patients were assigned to operative or nonoperative groups based on their electronic medical records. Volumetric mean T2* values were calculated within regions of interest (progeny lesion, interface, parent bone) and region matched control bone in healthy contralateral knees and condyles. The normalized percentage difference of T2* between baseline and follow up MRI in nonoperative patients significantly increased in progeny lesion (−47.8%, p < 0.001), parent bone (−13.9%, p < 0.001), and interface (−32.3%, p = 0.011), whereas the differences in op...
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Background: Understanding the morphology of cartilage/bony maturation in preadolescents may help explain adult trochlear variation. Purpose: To study trochlear morphology during maturation in children and infants using magnetic resonance... more
Background: Understanding the morphology of cartilage/bony maturation in preadolescents may help explain adult trochlear variation. Purpose: To study trochlear morphology during maturation in children and infants using magnetic resonance imaging (MRI). Study Design: Descriptive laboratory study. Methods: Twenty-four pediatric cadaveric knees (10 male and 14 female knees; age, 1 month to 10 years) were included. High-resolution imaging of the distal femoral secondary ossification center was performed using 7-T or 9.4-T MRI scanners. Three-dimensional MRI scans were produced, and images were reformatted; 3 slices in the axial, sagittal, and coronal planes images were analyzed, with coronal and sagittal imaging used for image orientation. Biometric analysis included lateral and medial trochlear height (TH); cartilaginous sulcus angle (CSA); osseous sulcus angle (OSA); trochlear depth; and trochlear facet (TF) length symmetry. Sex comparisons were considered when ≥1 specimen from both s...
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➤ Osteochondritis dissecans occurs most frequently in the active pediatric and young adult populations, commonly affecting the knee, elbow, or ankle, and may lead to premature osteoarthritis.➤ While generally considered an idiopathic... more
➤ Osteochondritis dissecans occurs most frequently in the active pediatric and young adult populations, commonly affecting the knee, elbow, or ankle, and may lead to premature osteoarthritis.➤ While generally considered an idiopathic phenomenon, various etiopathogenetic theories are being investigated, including local ischemia, aberrant endochondral ossification of the secondary subarticular physis, repetitive microtrauma, and genetic predisposition.➤ Diagnosis is based on the history, physical examination, radiography, and advanced imaging, with elbow ultrasonography and novel magnetic resonance imaging protocols potentially enabling early detection and in-depth staging.➤ Treatment largely depends on skeletal maturity and lesion stability, defined by the presence or absence of articular cartilage fracture and subchondral bone separation, as determined by imaging and arthroscopy, and is typically nonoperative for stable lesions in skeletally immature patients and operative for those...
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Juvenile osteochondritis dissecans (JOCD) lesions contain cartilaginous, fibrous and osseous tissues which are difficult to distinguish with clinical, morphological magnetic resonance imaging (MRI). Quantitative T 2 * mapping has earlier... more
Juvenile osteochondritis dissecans (JOCD) lesions contain cartilaginous, fibrous and osseous tissues which are difficult to distinguish with clinical, morphological magnetic resonance imaging (MRI). Quantitative T 2 * mapping has earlier been used to evaluate microstructure and composition of all aforementioned tissues as well as bone mineral density. However, the ability of T 2 * mapping to detect changes in tissue composition between different JOCD lesion regions, different disease stages, and between stable and unstable lesions has not been demonstrated. This study analyzed morphological and T 2 * MRI data from 25 patients (median age, 12.1 years) with 34 JOCD-affected and 13 healthy knees. Each lesion was assigned a stage reflecting the natural history of JOCD, with stages I and IV representing early and healed lesion, respectively. T 2 * values were evaluated within the progeny lesion, interface and parent bone of each lesion and in the control bone region. T 2 * was negatively correlated with JOCD stage in progeny lesion (ρ= -0.871; p<0.001) and interface regions (ρ= -0.649; p<0.001). Stage IV progeny showed significantly lower T 2 * than control bone (p=0.028). T 2 * was significantly lower in parent bone than in control bone of patients with stable lesions (p=0.009), but not in patients with unstable lesions (p=0.14). Clinical significance: T 2 * mapping enables differentiation between different stages of JOCD and quantitative measurement of the ossification degree in progeny lesion and interface. The observed T 2 * decrease in healed and stable lesions may indicate increased bone density as a result of the active repair process. T 2 * mapping provides quantitative information about JOCD lesion composition. This article is protected by copyright. All rights reserved.
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This study investigated the sensitivity of T1ρ and T2 relaxation time mapping to detect acute ischemic injury to the secondary ossification center (SOC) and epiphyseal cartilage of the femoral head in a piglet model of Legg–Calvé–Perthes... more
This study investigated the sensitivity of T1ρ and T2 relaxation time mapping to detect acute ischemic injury to the secondary ossification center (SOC) and epiphyseal cartilage of the femoral head in a piglet model of Legg–Calvé–Perthes disease. Six piglets underwent surgery to induce global right femoral head ischemia and were euthanized 48 h later. Fresh operated and contralateral‐control femoral heads were imaged ex vivo with T1, T2, and T1ρ mapping using a 9.4T magnetic resonance imaging scanner. The specimens were imaged a second time after a freeze/thaw cycle and then processed for histology. T1, T2, and T1ρ measurements in the SOC, epiphyseal cartilage, articular cartilage, and metaphysis were compared between operated and control femoral heads using paired t tests. The effects of freeze/thaw, T1ρ spin‐lock frequency, and fat saturation were also investigated. Five piglets with histologically confirmed ischemic injury were quantitatively analyzed. T1ρ was increased in the SO...
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Current clinical MRI of patients with juvenile osteochondritis dissecans (JOCD) is limited by the low reproducibility of lesion instability evaluation and inability to predict which lesions will heal after nonoperative treatment and which... more
Current clinical MRI of patients with juvenile osteochondritis dissecans (JOCD) is limited by the low reproducibility of lesion instability evaluation and inability to predict which lesions will heal after nonoperative treatment and which will later require surgery. The aim of this study is to verify the ability of apparent diffusion coefficient (ADC) to detect differences in lesion microstructure between different JOCD stages, treatment groups, and healthy, unaffected contralateral knees. Pediatric patients with JOCD received quantitative diffusion MRI between January 2016 and September 2020 in this prospective research study. A disease stage (I‐IV) and stability of each JOCD lesion was evaluated. ADCs were calculated in progeny lesion, interface, parent bone, cartilage overlying lesion, control bone, and control cartilage regions. ADC differences were evaluated using linear mixed models with Bonferroni correction. Evaluated were 30 patients (mean age, 13 years; 21 males), with 40 ...
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NMR-spectroscopy and electron microscopy were applied in order to find out whether nephrotoxic effects of cyclosporine A in combination with ischaemia on rat kidney are of significance for the energy metabolism of the organ. CSA was... more
NMR-spectroscopy and electron microscopy were applied in order to find out whether nephrotoxic effects of cyclosporine A in combination with ischaemia on rat kidney are of significance for the energy metabolism of the organ. CSA was administered in daily doses of 15 mg/kg rat over 20 days. Use was made of the particular advantage of 31P-NMR-spectroscopy to follow up the dynamics of high-energy phosphate concentrations in the same tissue. Ultrastructural changes were observed in the region of the proximal tubule. Some mitochondria showed degenerative changes, others increased density of cristae. The total number of mitochondria was increased. This observation together with the coexistence of vacuolarly degenerated mitochondria and mitochondria with increased activity after CSA treatment is interpreted as expression of a compensatory mechanism that keeps constant the totality of high-energy phosphates despite damage to some mitochondria.
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The effect of pentoxifylline on the recovery of renal energy metabolism after ischemia and reperfusion was studied by 31P nuclear magnetic resonance spectroscopy in vivo. Rat kidneys were exposed to 15, 30 and 60 min, respectively, of... more
The effect of pentoxifylline on the recovery of renal energy metabolism after ischemia and reperfusion was studied by 31P nuclear magnetic resonance spectroscopy in vivo. Rat kidneys were exposed to 15, 30 and 60 min, respectively, of ischemia by clamping the arteria renalis. Pre-ischemic application of pentoxifylline improves the recovery of renal energy metabolism. The concentration of ATP was found to be higher in pentoxifylline pretreated kidneys than in controls after ischemia. The 5'-nucleotidase inhibiting activity of pentoxifylline is suggested to be the mechanism responsible for the protective effect of the drug. 31P NMR spectroscopy proved to be a powerful tool for continuous follow-up of drug effects on metabolic processes.
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Deep learning based MRI reconstruction methods typically require databases of fully-sampled data as reference for training. However, fully-sampled acquisitions may be either challenging or impossible in numerous scenarios. Self-supervised... more
Deep learning based MRI reconstruction methods typically require databases of fully-sampled data as reference for training. However, fully-sampled acquisitions may be either challenging or impossible in numerous scenarios. Self-supervised learning enables training neural networks for MRI reconstruction without fully-sampled data by splitting available measurements into two disjoint sets. One of them is used in data consistency units in the network, and the other is used to define the loss. However, the performance of self-supervised learning degrades at high acceleration rates due to scarcity of acquired data. We propose a multi-mask self-supervised learning approach, which retrospectively splits available measurements into multiple 2-tuples of disjoint sets. Results on 3D knee and brain MRI shows that the proposed multi-mask self-supervised learning approach significantly improves upon single mask self-supervised learning at high acceleration rates.
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Objectives: Endochondral ossification is a skeletal developmental process in children by which the embryonic cartilaginous model of bones undergoes gradual ossification over time until skeletal maturity is reached. Juvenile... more
Objectives: Endochondral ossification is a skeletal developmental process in children by which the embryonic cartilaginous model of bones undergoes gradual ossification over time until skeletal maturity is reached. Juvenile Osteochondritis Dissecans (JOCD) is a developmental disease characterized by focal areas of chondronecrosis within the epiphyseal cartilage and subsequent delay of the ossification front. JOCD lesions can become loose bodies and lead to premature Osteoarthritis. The etiology of JOCD is not yet well understood, however, there is mounting evidence of a genetic predisposition. Recently, positive familial history, including familial OCD and a genome-wide association study in humans identified genetic loci related to juvenile OCD. In this longitudinal pilot study, we examined siblings of JOCD patients utilizing clinical 3T MRI data to evaluate morphological integrity of the epiphyseal cartilage and the advancing ossification front in the distal femoral condyles in bil...
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grade ≤ 1.5) and advanced OA (OARSI grade > 1.5) groups (*p<0.05, Mann-Whitney U test). Table 1. ROC AUCs for MR parameters and Spearman’s rank correlation coefficients (ρ) between OARSI grade and MR parameters for superficial and... more
grade ≤ 1.5) and advanced OA (OARSI grade > 1.5) groups (*p<0.05, Mann-Whitney U test). Table 1. ROC AUCs for MR parameters and Spearman’s rank correlation coefficients (ρ) between OARSI grade and MR parameters for superficial and full-thickness ROIs. All AUC values were significantly (p < 0.05) greater than 0.5, except for MTR in both ROIs. Param. / ROI AUC ρ (w/OARSI grade) Sup. Full Full T1 0.857 0.829 0.498 (p = 0.030) T1Gd 0.943 0.871 -0.680 (p = 0.001) T2 0.829 0.829 0.443 (p = 0.057) CW T1ρ 0.786 0.743 0.419 (p = 0.074) Adiab. T1ρ 0.871 0.871 0.569 (p = 0.011) Adiab. T2ρ 0.871 0.871 0.556 (p = 0.013) TRAFF 1.000 1.000 0.653 (p = 0.002) T1sat 0.857 0.829 0.572 (p = 0.010) MTR 0.543 0.521 -0.158 (p = 0.519) Multi-parametric MRI assessment of degeneration of human articular cartilage – association to histopathological grade Elli-Noora Salo, Jari Rautiainen, Virpi Tiitu, Mikko A. J. Finnilä, Olli-Matti Aho, Petri Lehenkari, Jutta Ellermann, Simo Saarakkala, Mikko J. Niss...
Femoroacetabular impingement (FAI) is a common source of hip pain in adults caused by a pathological abutment of the head-neck junction of the femur and the acetabular rim of the hip [6]. This abutment leads to mechanical friction, which... more
Femoroacetabular impingement (FAI) is a common source of hip pain in adults caused by a pathological abutment of the head-neck junction of the femur and the acetabular rim of the hip [6]. This abutment leads to mechanical friction, which can in turn cause labral and chondral lesions and lead to osteoarthritis (OA) [1, 2, 4, 5, 8]. The recommended treatment for FAI is joint preservation surgery if a labral tear has occurred, cartilage damage is not severe, and patient symptoms cannot be managed conservatively with physical therapy [3, 10, 11]. In FAI, cartilage damage is typically limited to the acetabulum and occurs deep within the tissue as a debonding of articular cartilage from underlying bone [2]. This so-called ‘cartilage delamination’ is the hallmark of the disease. If cartilage damage is severe, as would be the case if there was prevalent cartilage delamination, then joint preservation surgery will fail and total hip replacement will be necessary. Therefore, in order to appro...
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ABSTRACT
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The dorsal stream is a dominant visuomotor pathway that conappropriate motor output. Since the late 1960s two major nects the striate and extrastriate cortices to posterior parietal areas. visual pathways have been implicated in the... more
The dorsal stream is a dominant visuomotor pathway that conappropriate motor output. Since the late 1960s two major nects the striate and extrastriate cortices to posterior parietal areas. visual pathways have been implicated in the spatial control In turn, the posterior parietal areas send projections to the frontal of movement. As originally defined these two systems were primary motor and premotor areas. This cortical pathway is hyhypothesized to consist of the retinal projection to the supepothesized to be involved in the transformation of a visual input rior colliculus for localization of stimuli in space and the into the appropriate motor output. In this study we used functional geniculostriate system for the identification of stimuli (1). magnetic resonance imaging (f MRI) of the entire brain to deter-Although this initial hypothesis was an oversimplification, mine the patterns of activation that occurred while subjects perthe distinction between object identification and spatial loformed a visually guided motor task. In nine human subjects, calization-between ''what'' and ''where''-has persisted. f MRI data were acquired on a 4-T whole-body MR system
Fig.3 Separation of different spin pools and color coding of composite image of the pig specimen: red= fast relaxing, green=slow relaxing, blue= fat. The first figure shows the fast relaxing components (e.g.bone, calcified layer of the... more
Fig.3 Separation of different spin pools and color coding of composite image of the pig specimen: red= fast relaxing, green=slow relaxing, blue= fat. The first figure shows the fast relaxing components (e.g.bone, calcified layer of the cartilage and tightly bound collagen matrix part). SWIFT with magnetization preparation: Signal partitioning and 3D measurement of adiabatic T1rho in osteochondral specimen Jinjin Zhang, Mikko Johannes Nissi, Djaudat Idiyatullin, Shalom Michaeli, Michael Garwood, and Jutta Ellermann Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, United States, Department of Orthopedic Surgery, University of Minnesota, Minneapolis, Minnesota, United States
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To use quantitative susceptibility mapping (QSM) to investigate changes in cartilage canals in the distal femur of juvenile goats after their surgical transection. Chondronecrosis was surgically induced in the right medial femoral... more
To use quantitative susceptibility mapping (QSM) to investigate changes in cartilage canals in the distal femur of juvenile goats after their surgical transection. Chondronecrosis was surgically induced in the right medial femoral condyles of four 4-day-old goats. Both the operated and control knees were harvested at 2, 3, 5, and 10 weeks after the surgeries. Ex vivo MRI scans were conducted at 9.4 Tesla using TRAFF (relaxation time along a fictitious field)-weighted fast spin echo imaging and QSM to detect areas of chondronecrosis and investigate cartilage canal abnormalities. Histological sections from these same areas stained with hematoxylin and eosin and safranin O were evaluated to assess the affected tissues. Both the histological sections and the TRAFF -weighted images of the femoral condyles demonstrated focal areas of chondronecrosis, evidenced by pyknotic chondrocyte nuclei, loss of matrix staining, and altered MR image contrast. At increasing time points after surgery, p...
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Engineering, Algorithms, Biomedical Engineering, Magnetic Resonance Imaging, Medicine, and 11 moreCartilage, Animals, Physical sciences, Goats, Image Enhancement, Reproducibility of Results, Sensitivity and Specificity, Osteochondritis Dissecans, Asymptomatic Diseases., Medical and Health Sciences, and In Vitro Techniques
Identify and interrupt the vascular supply to portions of the distal femoral articular-epiphyseal cartilage complex (AECC) in goat kids to induce cartilage necrosis, characteristic of early lesions of osteochondrosis (OC); then utilize... more
Identify and interrupt the vascular supply to portions of the distal femoral articular-epiphyseal cartilage complex (AECC) in goat kids to induce cartilage necrosis, characteristic of early lesions of osteochondrosis (OC); then utilize magnetic resonance imaging (MRI) to identify necrotic areas of cartilage. Distal femora were perfused and cleared in goat kids of various ages to visualize the vascular supply to the distal femoral AECC. Vessels located on the axial aspect of the medial femoral condyle (MFC) and on the abaxial side of the lateral trochlear ridge were transected in eight 4- to 5-day-old goats to induce cartilage necrosis. Goats were euthanized 1, 2, 3, 4, 5, 6, 9, and 10 weeks post operatively and operated stifles were harvested. Adiabatic T1ρ relaxation time maps of the harvested distal femora were generated using a 9.4 T MR scanner, after which samples were evaluated histologically. Interruption of the vascular supply to the MFC caused lesions of cartilage necrosis i...
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Osteochondrosis (OC) is a common developmental orthopedic disease affecting both humans and animals. Despite increasing recognition of this disease among children and adolescents, its pathogenesis is incompletely understood because... more
Osteochondrosis (OC) is a common developmental orthopedic disease affecting both humans and animals. Despite increasing recognition of this disease among children and adolescents, its pathogenesis is incompletely understood because clinical signs are often not apparent until lesions have progressed to end-stage, and examination of cadaveric early lesions is not feasible. In contrast, both naturally-occurring and surgically-induced animal models of disease have been extensively studied, most notably in horses and swine, species in which OC is recognized to have profound health and economic implications. The potential for a translational model of human OC has not been recognized in the existing human literature. The purpose of this review is to highlight the similarities in signalment, predilection sites and clinical presentation of naturally-occurring OC in humans and animals and to propose a common pathogenesis for this condition across species. Review. The published human and veter...
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Engineering, Algorithms, Physics, Magnetic Resonance Imaging, Nuclear Magnetic Resonance, and 15 moreMedicine, Magnetic field, Brain Mapping, Brain, Humans, Mice, Animals, Physical sciences, Magnetic Resonance, Electromagnetic Fields, Human Brain, Dipole, Chemical Shift, Amplitude, and Rate Constant
There has recently been increased interest in the use of 7.0-T magnetic resonance imaging for evaluating articular cartilage degeneration and quantifying the progression of osteoarthritis. The purpose of this study was to evaluate... more
There has recently been increased interest in the use of 7.0-T magnetic resonance imaging for evaluating articular cartilage degeneration and quantifying the progression of osteoarthritis. The purpose of this study was to evaluate articular cartilage cross-sectional area and maximum thickness in the medial compartment of intact and destabilized canine knees using 7.0-T magnetic resonance images and compare these results with those obtained from the corresponding histologic sections. Controlled laboratory study. Five canines had a surgically created unilateral grade III posterolateral knee injury that was followed for 6 months before euthanasia. The opposite, noninjured knee was used as a control. At necropsy, 3-dimensional gradient echo images of the medial tibial plateau of both knees were obtained using a 7.0-T magnetic resonance imaging scanner. Articular cartilage area and maximum thickness in this site were digitally measured on the magnetic resonance images. The proximal tibias were processed for routine histologic analysis with hematoxylin and eosin staining. Articular cartilage area and maximum thickness were measured in histologic sections corresponding to the sites of the magnetic resonance slices. The magnetic resonance imaging results revealed an increase in articular cartilage area and maximum thickness in surgical knees compared with control knees in all specimens; these changes were significant for both parameters (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.05 for area; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.01 for thickness). The average increase in area was 14.8% and the average increase in maximum thickness was 15.1%. The histologic results revealed an average increase in area of 27.4% (P = .05) and an average increase in maximum thickness of 33.0% (P = .06). Correlation analysis between the magnetic resonance imaging and histology data revealed that the area values were significantly correlated (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .01), but the values for thickness obtained from magnetic resonance imaging were not significantly different from the histology sections (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .1). These results demonstrate that 7.0-T magnetic resonance imaging provides an alternative method to histology to evaluate early osteoarthritic changes in articular cartilage in a canine model by detecting increases in articular cartilage area. The noninvasive nature of 7.0-T magnetic resonance imaging will allow for in vivo monitoring of osteoarthritis progression and intervention in animal models and humans for osteoarthritis.