Publications by authors named "Karl E Jensen"

7 Publications

  • Page 1 of 1

Reliable Gait Recognition Using 3D Reconstructions and Random Forests - An Anthropometric Approach.

J Forensic Sci 2016 05 6;61(3):637-48. Epub 2016 Jan 6.

Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen, Denmark.

Photogrammetric measurements of bodily dimensions and analysis of gait patterns in CCTV are important tools in forensic investigations but accurate extraction of the measurements are challenging. This study tested whether manual annotation of the joint centers on 3D reconstructions could provide reliable recognition. Sixteen participants performed normal walking where 3D reconstructions were obtained continually. Segment lengths and kinematics from the extremities were manually extracted by eight expert observers. The results showed that all the participants were recognized, assuming the same expert annotated the data. Recognition based on data annotated by different experts was less reliable achieving 72.6% correct recognitions as some parameters were heavily affected by interobserver variability. This study verified that 3D reconstructions are feasible for forensic gait analysis as an improved alternative to conventional CCTV. However, further studies are needed to account for the use of different clothing, field conditions, etc.
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http://dx.doi.org/10.1111/1556-4029.13015DOI Listing
May 2016

Diagnosis of bone metastasis from thyroid carcinoma: a multidisciplinary approach.

Acta Radiol Open 2015 Nov 3;4(11):2058460115603248. Epub 2015 Nov 3.

Department of Radiology, Rigshospitalet, Copenhagen, Denmark.

Sarcomas are rare tumors originating from soft tissue or bone. Diagnosis and treatment of sarcomas should be performed at specialized sarcoma centers, where patients are evaluated at a multidisciplinary tumor conference. We present a case where sarcoma was suspected from magnetic resonance imaging (MRI), but histology revealed a metastasis from thyroid carcinoma, although the patient had no previous history of thyroid malignancy and resection of the thyroid gland was without malignancy. Ultrasound-guided biopsy was possible due to cortical destruction and the multidisciplinary approach with re-evaluation of previous pathology and a thorough patient history enabled a final diagnosis.
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http://dx.doi.org/10.1177/2058460115603248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4641552PMC
November 2015

New equations to calculate 3D joint centres in the lower extremities.

Med Eng Phys 2015 Oct 28;37(10):948-55. Epub 2015 Aug 28.

Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen, Denmark.

Biomechanical movement analysis in 3D requires estimation of joint centres in the lower extremities and this estimation is based on extrapolation from markers placed on anatomical landmarks. The purpose of the present study was to quantify the accuracy of three established set of equations and provide new improved equations to predict the joint centre locations. The 'true' joint centres of the knee and ankle joint were obtained in vivo by MRI scans on 10 male subjects whereas the 'true' hip joint centre was obtained in 10 male and 10 female cadavers by CT scans. For the hip joint the errors ranged from 26.7 (8.9) to 29.6 (7.5) mm, for the knee joint 5.8 (3.1) to 22.6 (3.3) mm and for the ankle joint 14.4 (2.2) to 27.0 (4.6) mm. This differed significantly from the improved equations by which the error for the hip joint ranged from 8.2 (3.6) to 11.6 (5.6) mm, for the knee joint from 2.9 (2.1) to 4.7 (2.5) mm and for the ankle joint from 3.4 (1.3) to 4.1 (2.0) mm. The coefficients in the new hip joint equations differed significantly between sexes. This difference depends on anatomical differences of the male and female pelvis.
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http://dx.doi.org/10.1016/j.medengphy.2015.07.001DOI Listing
October 2015

A non-fatal case of invasive zygomycete (Lichtheimia corymbifera) infection in an allogeneic haematopoietic cell transplant recipient.

APMIS 2013 May 23;121(5):456-9. Epub 2012 Nov 23.

Department of International Health, Immunology & Microbiology, The Faculty of Health Sciences, The University of Copenhagen, Copenhagen, Denmark.

Post-transplant infections in allogeneic haematopoietic cell transplant (allo-HCT) recipients often have severe consequences. This is especially the case when dealing with zygomycete infections where the result is often fatal. A major problem when dealing with zygomycete infections is the need for an accurate and fast diagnosis as the phylum is highly resistant towards the conventional antifungals. We herein describe a non-fatal case of Lichtheimia corymbifera infection in an allo-HCT recipient.
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http://dx.doi.org/10.1111/apm.12008DOI Listing
May 2013

Fast and robust analysis of dynamic contrast enhanced MRI datasets.

Med Image Comput Comput Assist Interv 2007 ;10(Pt 2):261-9

School of Computing, University of Leeds, UK.

A fully automated method for quantitative analysis of dynamic contrast-enhanced MRI data acquired with low and high field scanners, using spin echo and gradient echo sequences, depicting various joints is presented. The method incorporates efficient pre-processing techniques and a robust algorithm for quantitative assessment of dynamic signal intensity vs. time curves. It provides differentiated information to the reader regarding areas with the most active perfusion and permits depiction of different disease activity in separate compartments of a joint. Additionally, it provides information on the speed of contrast agent uptake by various tissues. The method delivers objective and easily reproducible results, which have been favourably viewed by a number of medical experts.
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http://dx.doi.org/10.1007/978-3-540-75759-7_32DOI Listing
January 2008

Outcome of isolated tibial polyethylene insert exchange after uncemented total knee arthroplasty: 27 patients followed for 8-71 months.

Acta Orthop 2006 Dec;77(6):917-20

Department of Orthopedics U, Rigshospitalet, National University Hospital, Copenhagen, Denmark.

Background: The outcome of performing isolated tibial polyethylene insert exchange (ITPIE) after total knee arthroplasty (TKA) is under debate. We evaluated the survival probability of ITPE after uncemented TKA.

Method: 27 patients (27 knees) with an ITPIE performed mean 9 (0.9-17) years after the initial TKA were included in the study (22 patients also had the patellar component replaced simultaneously). All patients had their exchange performed at our department between 1997 and 2001 and had their latest follow-up examination mean 40 (8-71) months after the exchange.

Results: During the follow-up, 2 patients had total knee revision because of aseptic loosening and 2 patients had isolated patella component exchange (in 1 of the patients, combined with a new ITPIE). Kaplan-Meier survival analysis gave a survival probability of 80% at 34 months of follow-up.

Interpretation: The short-term survival after an ITPIE was similar to that of a total knee revision with exchange of all components. Since the ITPIE is a much smaller operation with fast rehabilitation, we recommend it in elderly patients with a well-fixed and wellaligned prosthesis without surface damage of the components.
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http://dx.doi.org/10.1080/17453670610013222DOI Listing
December 2006

Ultrasonography of the metacarpophalangeal and proximal interphalangeal joints in rheumatoid arthritis: a comparison with magnetic resonance imaging, conventional radiography and clinical examination.

Arthritis Res Ther 2006 6;8(2):R52. Epub 2006 Mar 6.

Department of Rheumatology, University of Copenhagen Hvidovre Hospital, Kettegård Allé 30, 2650 Hvidovre, Denmark.

Signs of inflammation and destruction in the finger joints are the principal features of rheumatoid arthritis (RA). There are few studies assessing the sensitivity and specificity of ultrasonography in detecting these signs. The objective of the present study was to investigate whether ultrasonography can provide information on signs of inflammation and destruction in RA finger joints that are not available with conventional radiography and clinical examination, and comparable to the information provided by magnetic resonance imaging (MRI). The second to fifth metacarpophalangeal and proximal interphalangeal joints of 40 RA patients and 20 control persons were assessed with ultrasonography, clinical examination, radiography and MRI. With MRI as the reference method, the sensitivity, specificity and accuracy of ultrasonography in detecting bone erosions in the finger joints were 0.59, 0.98 and 0.96, respectively; they were 0.42, 0.99 and 0.95 for radiography. The sensitivity, specificity and accuracy of ultrasonography, with signs of inflammation on T1-weighted MRI sequences as the reference method, were 0.70, 0.78 and 0.76, respectively; they were 0.40, 0.85 and 0.72 for the clinical examination. With MRI as the reference method, ultrasonography had higher sensitivity and accuracy in detecting signs of inflammation and destruction in RA finger joints than did clinical and radiographic examinations, without loss of specificity. This study shows that ultrasonography has the potential to improve assessment of patients with RA.
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http://dx.doi.org/10.1186/ar1904DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1526591PMC
August 2006
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