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Xavier Golay - One of the best experts on this subject based on the ideXlab platform.
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cerebral border zones between Distal End branches of intracranial arteries mr imaging
Radiology, 2008Co-Authors: Jeroen Hendrikse, Esben Thade Petersen, Peter Jan Van Laar, Xavier GolayAbstract:This study had institutional review board approval; informed consent was obtained from all participants. The study purpose was to prospectively determine whether a longer arterial transit time (ATT), from the proximal vasculature in the neck toward the Distal End branches of the intracranial arteries, can be utilized to identify cerebral border zone regions. A magnetic resonance (MR) imaging method based on noninvasive arterial spin-labeling (ASL) perfusion MR imaging with image acquisition at a series of increasing delay times was used to quantify regional ATTs. Fifteen healthy volunteers (age range, 22–34 years; nine men, six women) were included. ASL perfusion MR imaging demonstrated an increase in ATT in the cerebral border zone regions, extEnding from the frontal and occipital horns of the lateral ventricle to the frontal and parietooccipital cortices, relative to ATT in non–border zone regions. Cerebral blood flow and arterial blood volume in these anterior and posterior border zone regions were sig...
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cerebral border zones between Distal End branches of intracranial arteries mr imaging
Radiology, 2008Co-Authors: Jeroen Hendrikse, Esben Thade Petersen, Peter Jan Van Laar, Xavier GolayAbstract:This study had institutional review board approval; informed consent was obtained from all participants. The study purpose was to prospectively determine whether a longer arterial transit time (ATT), from the proximal vasculature in the neck toward the Distal End branches of the intracranial arteries, can be utilized to identify cerebral border zone regions. A magnetic resonance (MR) imaging method based on noninvasive arterial spin-labeling (ASL) perfusion MR imaging with image acquisition at a series of increasing delay times was used to quantify regional ATTs. Fifteen healthy volunteers (age range, 22-34 years; nine men, six women) were included. ASL perfusion MR imaging demonstrated an increase in ATT in the cerebral border zone regions, extEnding from the frontal and occipital horns of the lateral ventricle to the frontal and parietooccipital cortices, relative to ATT in non-border zone regions. Cerebral blood flow and arterial blood volume in these anterior and posterior border zone regions were significantly lower (P < .001) than in non-border zone regions.
Peter Muir - One of the best experts on this subject based on the ideXlab platform.
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Computed Tomographic Imaging of Subchondral Fatigue Cracks in the Distal End of the Third Metacarpal Bone in the Thoroughbred Racehorse Can Predict Crack Micromotion in an Ex-Vivo Model
2016Co-Authors: Mariesoleil Dubois, Patricia Marquis, Vicki L. Kalscheur, Mark D. Markel, Kelsey Rayment, Ronald P Mccabe, Samantha Morello, Zhengling Hao, Peter MuirAbstract:Articular stress fracture arising from the Distal End of the third metacarpal bone (MC3) is a common serious injury in Thoroughbred racehorses. Currently, there is no method for predicting fracture risk clinically. We describe an ex-vivo biomechanical model in which we measured subchondral crack micromotion under compressive loading that modeled high speed running. Using this model, we determined the relationship between subchondral crack dimensions measured using computed tomography (CT) and crack micromotion. Thoracic limbs from 40 Thoroughbred racehorses that had sustained a catastrophic injury were studied. Limbs were radiographed and examined using CT. Parasagittal subchondral fatigue crack dimensions were measured on CT images using image analysis software. MC3 bones with fatigue cracks were tested using five cycles of compressive loading at-7,500N (38 condyles, 18 horses). Crack motion was recorded using an extensometer. Mechanical testing was validated using bones with 3 mm and 5 mm deep parasagittal subchondral slots that modeled naturally occurring fatigue cracks. After testing, subchondral crack density was determined histologically. Creation of parasagittal subchondral slots induced significant micromotion during loading (p,0.001). In our biomechanical model, we found a significant positive correlation between extensometer micromotion and parasagittal crack area derived from reconstructed CT images (SR = 0.32, p,0.05). Correlations with transverse and frontal plane crack lengths were not significant. Histologic fatigue damage was not significantly correlated with crack dimensions determined by CT o
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computed tomographic imaging of subchondral fatigue cracks in the Distal End of the third metacarpal bone in the thoroughbred racehorse can predict crack micromotion in an ex vivo model
PLOS ONE, 2014Co-Authors: Mariesoleil Dubois, Patricia Marquis, Vicki L. Kalscheur, Mark D. Markel, Samantha L Morello, Kelsey Rayment, Ray Vanderby, Ronald P Mccabe, Peter MuirAbstract:: Articular stress fracture arising from the Distal End of the third metacarpal bone (MC3) is a common serious injury in Thoroughbred racehorses. Currently, there is no method for predicting fracture risk clinically. We describe an ex-vivo biomechanical model in which we measured subchondral crack micromotion under compressive loading that modeled high speed running. Using this model, we determined the relationship between subchondral crack dimensions measured using computed tomography (CT) and crack micromotion. Thoracic limbs from 40 Thoroughbred racehorses that had sustained a catastrophic injury were studied. Limbs were radiographed and examined using CT. Parasagittal subchondral fatigue crack dimensions were measured on CT images using image analysis software. MC3 bones with fatigue cracks were tested using five cycles of compressive loading at -7,500N (38 condyles, 18 horses). Crack motion was recorded using an extensometer. Mechanical testing was validated using bones with 3 mm and 5 mm deep parasagittal subchondral slots that modeled naturally occurring fatigue cracks. After testing, subchondral crack density was determined histologically. Creation of parasagittal subchondral slots induced significant micromotion during loading (p<0.001). In our biomechanical model, we found a significant positive correlation between extensometer micromotion and parasagittal crack area derived from reconstructed CT images (SR = 0.32, p<0.05). Correlations with transverse and frontal plane crack lengths were not significant. Histologic fatigue damage was not significantly correlated with crack dimensions determined by CT or extensometer micromotion. Bones with parasagittal crack area measurements above 30 mm2 may have a high risk of crack propagation and condylar fracture in vivo because of crack micromotion. In conclusion, our results suggest that CT could be used to quantify subchondral fatigue crack dimensions in racing Thoroughbred horses in-vivo to assess risk of condylar fracture. Horses with parasagittal crack arrays that exceed 30 mm2 may have a high risk for development of condylar fracture.
Jeroen Hendrikse - One of the best experts on this subject based on the ideXlab platform.
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cerebral border zones between Distal End branches of intracranial arteries mr imaging
Radiology, 2008Co-Authors: Jeroen Hendrikse, Esben Thade Petersen, Peter Jan Van Laar, Xavier GolayAbstract:This study had institutional review board approval; informed consent was obtained from all participants. The study purpose was to prospectively determine whether a longer arterial transit time (ATT), from the proximal vasculature in the neck toward the Distal End branches of the intracranial arteries, can be utilized to identify cerebral border zone regions. A magnetic resonance (MR) imaging method based on noninvasive arterial spin-labeling (ASL) perfusion MR imaging with image acquisition at a series of increasing delay times was used to quantify regional ATTs. Fifteen healthy volunteers (age range, 22–34 years; nine men, six women) were included. ASL perfusion MR imaging demonstrated an increase in ATT in the cerebral border zone regions, extEnding from the frontal and occipital horns of the lateral ventricle to the frontal and parietooccipital cortices, relative to ATT in non–border zone regions. Cerebral blood flow and arterial blood volume in these anterior and posterior border zone regions were sig...
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cerebral border zones between Distal End branches of intracranial arteries mr imaging
Radiology, 2008Co-Authors: Jeroen Hendrikse, Esben Thade Petersen, Peter Jan Van Laar, Xavier GolayAbstract:This study had institutional review board approval; informed consent was obtained from all participants. The study purpose was to prospectively determine whether a longer arterial transit time (ATT), from the proximal vasculature in the neck toward the Distal End branches of the intracranial arteries, can be utilized to identify cerebral border zone regions. A magnetic resonance (MR) imaging method based on noninvasive arterial spin-labeling (ASL) perfusion MR imaging with image acquisition at a series of increasing delay times was used to quantify regional ATTs. Fifteen healthy volunteers (age range, 22-34 years; nine men, six women) were included. ASL perfusion MR imaging demonstrated an increase in ATT in the cerebral border zone regions, extEnding from the frontal and occipital horns of the lateral ventricle to the frontal and parietooccipital cortices, relative to ATT in non-border zone regions. Cerebral blood flow and arterial blood volume in these anterior and posterior border zone regions were significantly lower (P < .001) than in non-border zone regions.
Jesse B Jupiter - One of the best experts on this subject based on the ideXlab platform.
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intra articular fractures of the Distal End of the radius in young adults reexamined as evidence based and outcomes medicine
Journal of Bone and Joint Surgery American Volume, 2009Co-Authors: Brian M Haus, Jesse B JupiterAbstract:The article “Intra-Articular Fractures of the Distal End of the Radius in Young Adults,” by Knirk and Jupiter, published in The Journal of Bone and Joint Surgery1 in 1986, in its day, was arguably one of the most important works on the management of intra-articular fractures of the Distal End of the radius. Prior to the publication of that study, the critical factors that determined successful long-term management of intra-articular Distal radial fractures in young patients had not been determined. The finding with the greatest impact on treatment algorithms was that accurate articular restoration was the most critical factor in preventing long-term arthritis in young patients with intra-articular Distal radial fractures. However, twenty-three years of advancements in orthopaedic surgery and technology have exposed the methodological flaws of that study. The radiographic analysis incorrectly interpreted fracture lines, and the study failed to use intraobserver and interobserver validation in its analysis. The study also was conducted before the popularization of computerized tomography and wrist arthroscopy. Despite these shortcomings, an updated critical analysis reveals that its conclusions are still germane in today's treatment of Distal radial fractures in young adults. The study by Knirk and Jupiter1 has been cited in 330 research and scholarly articles. Although it is sometimes inaccurately referenced2, it ranks among the most cited manuscripts in the orthopaedic surgery literature. Today, its conclusions not only direct the treatment of Distal radial fractures but they also continue to generate hypotheses for outcome studies. Given the impact of the study on the standard of care and orthopaedic research, it is appropriate to critically review its methodology to determine whether the findings remain relevant today. Intra-articular fractures of the Distal End of the radius in the young adult are a distinct group of fractures that can lead to accelerated …
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operative treatment of volar intra articular fractures of the Distal End of the radius
Journal of Bone and Joint Surgery American Volume, 1996Co-Authors: Jesse B Jupiter, Diego L Fernandez, Choonlai Toh, Thomas Fellman, David RingAbstract:We retrospectively reviewed the results of operative treatment of forty-nine volar marginal intra-articular fractures of the Distal End of the radius. According to the Comprehensive Classification of Fractures, there were two B3.1 fractures (characterized by a small volar fragment, with the sigmoid notch intact), three B3.2 fractures (characterized by a large volar fragment that included the sigmoid notch), and forty-four B3.3 fractures (characterized by comminution of the volar fragment). Although all fractures healed and only nine patients had evidence of osteoarthrosis on follow-up radiographs, there were six early and fourteen late complications, some of which adversely influenced the over-all outcome. After an average of fifty-one months (range, twenty-four to 117 months), there were thirty-one excellent, ten good, and eight fair results according to the system described by Gartland and Werley, and thirty-two excellent, nine good, five fair, and three poor results according to the modified system of Green and O'Brien. Two factors were found to have a significant association with a fair or poor outcome: evidence of osteoarthrosis on the most recent follow-up radiographs and reversal of the normal volar tilt of the Distal End of the radius. The age of the patient, the interval from the injury to the operation, a concomitant injury of the ipsilateral upper extremity, an associated fracture of the ulnar styloid process, the radio-ulnar index, ulnar angulation, the classification of the fracture, comminution of the volar fragment, and articular incongruity were not significantly associated with the outcome.
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a comparison of early and late reconstruction of malunited fractures of the Distal End of the radius
Journal of Bone and Joint Surgery American Volume, 1996Co-Authors: Jesse B Jupiter, David RingAbstract:AbstractWe retrospectively evaluated the results for ten patients in whom a malaligned fracture of the Distal End of the radius had been treated with early reconstruction (an average of eight weeks [range, six to fourteen weeks] after the injury) consisting of an osteotomy through the site of the fr
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coronal shear fractures of the Distal End of the humerus
Journal of Bone and Joint Surgery American Volume, 1996Co-Authors: Michael D Mckee, Jesse B Jupiter, Brent Do H BambergerAbstract:We identified a shear fracture of the Distal articular surface of the humerus, with anterior and proximal displacement of the capitellum and a portion of the trochlea, in six patients (five female and one male). The average age of the patients was thirty-eight years (range, ten to sixty-three years). Each fracture was the result of a fall from a standing height. A characteristic radiographic abnormality, which we have termed the double-arc sign, was seen on the lateral radiograph of each patient and represented the subchondral bone of the displaced capitellum and the lateral trochlear ridge. All patients were managed with open reduction, internal fixation, and early motion of the elbow. The average duration of follow-up was twenty-two months (range, eighteen to twenty-six months). The fracture united in all patients at an average of six weeks (range, four to nine weeks), without radiographic evidence of osteonecrosis of the fracture fragment. Flexion of the elbow averaged 141 degrees (range, 130 to 150 degrees), with an average flexion contracture of 15 degrees (range, 0 to 40 degrees). Pronation of the forearm averaged 83 degrees, and supination averaged 84 degrees. All patients had a good or excellent functional result, according to the elbow-rating scale of Broberg and Morrey.
Mariesoleil Dubois - One of the best experts on this subject based on the ideXlab platform.
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Computed Tomographic Imaging of Subchondral Fatigue Cracks in the Distal End of the Third Metacarpal Bone in the Thoroughbred Racehorse Can Predict Crack Micromotion in an Ex-Vivo Model
2016Co-Authors: Mariesoleil Dubois, Patricia Marquis, Vicki L. Kalscheur, Mark D. Markel, Kelsey Rayment, Ronald P Mccabe, Samantha Morello, Zhengling Hao, Peter MuirAbstract:Articular stress fracture arising from the Distal End of the third metacarpal bone (MC3) is a common serious injury in Thoroughbred racehorses. Currently, there is no method for predicting fracture risk clinically. We describe an ex-vivo biomechanical model in which we measured subchondral crack micromotion under compressive loading that modeled high speed running. Using this model, we determined the relationship between subchondral crack dimensions measured using computed tomography (CT) and crack micromotion. Thoracic limbs from 40 Thoroughbred racehorses that had sustained a catastrophic injury were studied. Limbs were radiographed and examined using CT. Parasagittal subchondral fatigue crack dimensions were measured on CT images using image analysis software. MC3 bones with fatigue cracks were tested using five cycles of compressive loading at-7,500N (38 condyles, 18 horses). Crack motion was recorded using an extensometer. Mechanical testing was validated using bones with 3 mm and 5 mm deep parasagittal subchondral slots that modeled naturally occurring fatigue cracks. After testing, subchondral crack density was determined histologically. Creation of parasagittal subchondral slots induced significant micromotion during loading (p,0.001). In our biomechanical model, we found a significant positive correlation between extensometer micromotion and parasagittal crack area derived from reconstructed CT images (SR = 0.32, p,0.05). Correlations with transverse and frontal plane crack lengths were not significant. Histologic fatigue damage was not significantly correlated with crack dimensions determined by CT o
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computed tomographic imaging of subchondral fatigue cracks in the Distal End of the third metacarpal bone in the thoroughbred racehorse can predict crack micromotion in an ex vivo model
PLOS ONE, 2014Co-Authors: Mariesoleil Dubois, Patricia Marquis, Vicki L. Kalscheur, Mark D. Markel, Samantha L Morello, Kelsey Rayment, Ray Vanderby, Ronald P Mccabe, Peter MuirAbstract:: Articular stress fracture arising from the Distal End of the third metacarpal bone (MC3) is a common serious injury in Thoroughbred racehorses. Currently, there is no method for predicting fracture risk clinically. We describe an ex-vivo biomechanical model in which we measured subchondral crack micromotion under compressive loading that modeled high speed running. Using this model, we determined the relationship between subchondral crack dimensions measured using computed tomography (CT) and crack micromotion. Thoracic limbs from 40 Thoroughbred racehorses that had sustained a catastrophic injury were studied. Limbs were radiographed and examined using CT. Parasagittal subchondral fatigue crack dimensions were measured on CT images using image analysis software. MC3 bones with fatigue cracks were tested using five cycles of compressive loading at -7,500N (38 condyles, 18 horses). Crack motion was recorded using an extensometer. Mechanical testing was validated using bones with 3 mm and 5 mm deep parasagittal subchondral slots that modeled naturally occurring fatigue cracks. After testing, subchondral crack density was determined histologically. Creation of parasagittal subchondral slots induced significant micromotion during loading (p<0.001). In our biomechanical model, we found a significant positive correlation between extensometer micromotion and parasagittal crack area derived from reconstructed CT images (SR = 0.32, p<0.05). Correlations with transverse and frontal plane crack lengths were not significant. Histologic fatigue damage was not significantly correlated with crack dimensions determined by CT or extensometer micromotion. Bones with parasagittal crack area measurements above 30 mm2 may have a high risk of crack propagation and condylar fracture in vivo because of crack micromotion. In conclusion, our results suggest that CT could be used to quantify subchondral fatigue crack dimensions in racing Thoroughbred horses in-vivo to assess risk of condylar fracture. Horses with parasagittal crack arrays that exceed 30 mm2 may have a high risk for development of condylar fracture.