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Adaptive registration of varying contrast-weighted images for improved tissue characterization (ARCTIC): application to T1 mapping.

https://arctichealth.org/en/permalink/ahliterature268568
Source
Magn Reson Med. 2015 Apr;73(4):1469-82
Publication Type
Article
Date
Apr-2015
Author
Sébastien Roujol
Murilo Foppa
Sebastian Weingärtner
Warren J Manning
Reza Nezafat
Source
Magn Reson Med. 2015 Apr;73(4):1469-82
Date
Apr-2015
Language
English
Publication Type
Article
Keywords
Algorithms
Artifacts
Female
Humans
Image Enhancement - methods
Image Interpretation, Computer-Assisted - methods
Magnetic Resonance Imaging, Cine - methods
Male
Middle Aged
Motion
Myocardium - pathology
Pattern Recognition, Automated - methods
Reproducibility of Results
Sensitivity and specificity
Subtraction Technique
Abstract
To propose and evaluate a novel nonrigid image registration approach for improved myocardial T1 mapping.
Myocardial motion is estimated as global affine motion refined by a novel local nonrigid motion estimation algorithm. A variational framework is proposed, which simultaneously estimates motion field and intensity variations, and uses an additional regularization term to constrain the deformation field using automatic feature tracking. The method was evaluated in 29 patients by measuring the DICE similarity coefficient and the myocardial boundary error in short axis and four chamber data. Each image series was visually assessed as "no motion" or "with motion." Overall T1 map quality and motion artifacts were assessed in the 85 T1 maps acquired in short axis view using a 4-point scale (1-nondiagnostic/severe motion artifact, 4-excellent/no motion artifact).
Increased DICE similarity coefficient (0.78 ± 0.14 to 0.87 ± 0.03, P
Notes
Cites: Med Image Anal. 1998 Mar;2(1):1-3610638851
Cites: Magn Reson Med. 2014 Mar;71(3):1024-3423650078
Cites: N Engl J Med. 2000 Nov 16;343(20):1445-5311078769
Cites: Radiology. 2001 Jan;218(1):215-2311152805
Cites: IEEE Trans Med Imaging. 2002 Sep;21(9):1011-2112564869
Cites: Magn Reson Med. 2004 Jul;52(1):141-615236377
Cites: Circulation. 1991 Jun;83(6):1849-651828192
Cites: J Comput Assist Tomogr. 1992 Mar-Apr;16(2):327-321545039
Cites: Circulation. 1994 Jan;89(1):151-638281642
Cites: J Mol Cell Cardiol. 1995 Jan;27(1):291-3057760353
Cites: Magn Reson Med. 1995 May;33(5):713-97596276
Cites: Radiology. 1999 Jun;211(3):698-70810352594
Cites: J Am Coll Cardiol. 2008 Nov 4;52(19):1574-8019007595
Cites: Magn Reson Med. 2010 Apr;63(4):1080-720373409
Cites: J Cardiovasc Magn Reson. 2010;12:6921092095
Cites: Future Cardiol. 2011 Sep;7(5):643-5021929344
Cites: IEEE Trans Med Imaging. 2011 Oct;30(10):1737-4521550879
Cites: Circ Cardiovasc Imaging. 2011 Nov;4(6):636-4021917782
Cites: IEEE Trans Inf Technol Biomed. 2012 May;16(3):365-7422411045
Cites: Magn Reson Med. 2012 Jun;67(6):1644-5522135227
Cites: J Cardiovasc Magn Reson. 2012;14:6322963517
Cites: Magn Reson Med. 2013 Jan;69(1):163-7022488966
Cites: Magn Reson Med. 2013 May;69(5):1408-2022736380
Cites: J Cardiovasc Magn Reson. 2013;15:5623800276
Cites: Magn Reson Med. 2014 Jun;71(6):2082-9523881866
Cites: Magn Reson Med. 2014 Feb;71(2):823-923440632
Cites: Herz. 2000 Jun;25(4):384-9110948774
PubMed ID
24798588 View in PubMed
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Alterations in regional homogeneity of resting-state brain activity in autism spectrum disorders.

https://arctichealth.org/en/permalink/ahliterature98452
Source
Brain Res. 2010 Mar 19;1321:169-79
Publication Type
Article
Date
Mar-19-2010
Author
Jyri-Johan Paakki
Jukka Rahko
Xiangyu Long
Irma Moilanen
Osmo Tervonen
Juha Nikkinen
Tuomo Starck
Jukka Remes
Tuula Hurtig
Helena Haapsamo
Katja Jussila
Sanna Kuusikko-Gauffin
Marja-Leena Mattila
Yufeng Zang
Vesa Kiviniemi
Author Affiliation
Department of Diagnostic Radiology, University Hospital of Oulu, PO Box 50, 90029 Oulu, Finland. jyri-johan.paakki@ppshp.fi
Source
Brain Res. 2010 Mar 19;1321:169-79
Date
Mar-19-2010
Language
English
Publication Type
Article
Keywords
Adolescent
Brain - physiopathology
Brain Mapping - methods
Child
Child Development Disorders, Pervasive - physiopathology
Female
Humans
Image Interpretation, Computer-Assisted - methods
Magnetic Resonance Imaging
Male
Rest
Abstract
Measures assessing resting-state brain activity with blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) can reveal cognitive disorders at an early stage. Analysis of regional homogeneity (ReHo) measures the local synchronization of spontaneous fMRI signals and has been successfully utilized in detecting alterations in subjects with attention-deficit hyperactivity disorder (ADHD), depression, schizophrenia, Parkinson's disease and Alzheimer's dementia. Resting-state brain activity was investigated in 28 adolescents with autism spectrum disorders (ASD) and 27 typically developing controls being imaged with BOLD fMRI and analyzed with the ReHo method. The hypothesis was that ReHo of resting-state brain activity would be different between ASD subjects and controls in brain areas previously shown to display functional alterations in stimulus or task based fMRI studies. Compared with the controls, the subjects with ASD had significantly decreased ReHo in right superior temporal sulcus region, right inferior and middle frontal gyri, bilateral cerebellar crus I, right insula and right postcentral gyrus. Significantly increased ReHo was discovered in right thalamus, left inferior frontal and anterior subcallosal gyrus and bilateral cerebellar lobule VIII. We conclude that subjects with ASD have right dominant ReHo alterations of resting-state brain activity, i.e., areas known to exhibit abnormal stimulus or task related functionality. Our results demonstrate that there is potential in utilizing the ReHo method in fMRI analyses of ASD.
PubMed ID
20053346 View in PubMed
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An audit of performance, interpretation, and influence of pretherapeutic MRI in rectal cancer: a Swedish population-based cohort study.

https://arctichealth.org/en/permalink/ahliterature302524
Source
Acta Radiol. 2019 Aug; 60(8):955-961
Publication Type
Journal Article
Date
Aug-2019

An echocardiographic study of the limitations of the Tei index in aortic stenosis.

https://arctichealth.org/en/permalink/ahliterature150648
Source
Echocardiography. 2009 Sep;26(8):891-9
Publication Type
Article
Date
Sep-2009
Author
Sachin Sud
David Massel
Author Affiliation
Department of Medicine, Division of Cardiology, London Health Sciences Centre, University Campus, University of Western Ontario, Ontario, Canada.
Source
Echocardiography. 2009 Sep;26(8):891-9
Date
Sep-2009
Language
English
Publication Type
Article
Keywords
Aorta - ultrasonography
Aortic Valve Stenosis - ultrasonography
Canada
Echocardiography - methods - standards
Humans
Image Interpretation, Computer-Assisted - methods
Reproducibility of Results
Sensitivity and specificity
Abstract
The omnibus Tei index, the sum of isovolumic contraction and relaxation times divided by the ejection time, is a good indicator of global cardiac function. However, these time intervals can be influenced by valvular heart disease and the role of the Tei index among patients with aortic stenosis (AS) and left ventricular systolic dysfunction remains incompletely defined.
Doppler time intervals were measured retrospectively by two observers, and the Tei index were calculated on 80 patients with various degrees of left ventricular systolic dysfunction and severity of AS. Differences between observers were resolved by consensus. Ejection fraction (EF) was visually estimated, and the aortic valve area (AVA) was calculated using the continuity equation.
The mean AVA was 1.1+/-0.5 cm(2) and the mean EF was 0.39+/-0.15. Although correlation (r = 0.61, P
PubMed ID
19486114 View in PubMed
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Automated extraction of temporal motor activity signals from video recordings of neonatal seizures based on adaptive block matching.

https://arctichealth.org/en/permalink/ahliterature58176
Source
IEEE Trans Biomed Eng. 2005 Apr;52(4):676-86
Publication Type
Article
Date
Apr-2005
Author
Nicolaos B Karayiannis
Abdul Sami
James D Frost
Merrill S Wise
Eli M Mizrahi
Author Affiliation
Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204-4005, USA. karayiannis@uh.edu
Source
IEEE Trans Biomed Eng. 2005 Apr;52(4):676-86
Date
Apr-2005
Language
English
Publication Type
Article
Keywords
Algorithms
Artificial Intelligence
Cluster analysis
Comparative Study
Feedback
Humans
Image Enhancement - methods
Image Interpretation, Computer-Assisted - methods
Infant, Newborn
Infant, Newborn, Diseases - diagnosis - physiopathology
Information Storage and Retrieval - methods
Intensive Care, Neonatal - methods
Models, Biological
Monitoring, Physiologic - methods
Motor Activity
Numerical Analysis, Computer-Assisted
Pattern Recognition, Automated - methods
Reproducibility of Results
Research Support, U.S. Gov't, P.H.S.
Seizures - diagnosis - physiopathology
Sensitivity and specificity
Signal Processing, Computer-Assisted
Subtraction Technique
Video Recording - methods
Abstract
This paper presents an automated procedure developed to extract quantitative information from video recordings of neonatal seizures in the form of motor activity signals. This procedure relies on optical flow computation to select anatomical sites located on the infants' body parts. Motor activity signals are extracted by tracking selected anatomical sites during the seizure using adaptive block matching. A block of pixels is tracked throughout a sequence of frames by searching for the most similar block of pixels in subsequent frames; this search is facilitated by employing various update strategies to account for the changing appearance of the block. The proposed procedure is used to extract temporal motor activity signals from video recordings of neonatal seizures and other events not associated with seizures.
PubMed ID
15825869 View in PubMed
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Average glandular dose in routine mammography screening using a Sectra MicroDose Mammography unit.

https://arctichealth.org/en/permalink/ahliterature16975
Source
Radiat Prot Dosimetry. 2005;114(1-3):436-43
Publication Type
Article
Date
2005
Author
Bengt Hemdal
Lars Herrnsdorf
Ingvar Andersson
Gert Bengtsson
Boel Heddson
Magnus Olsson
Author Affiliation
Department of Medical Radiation Physics, Lund University, Malmö University Hospital, SE-205 02 Malmö, Sweden. bengt.hemdal@rfa.mas.lu.se
Source
Radiat Prot Dosimetry. 2005;114(1-3):436-43
Date
2005
Language
English
Publication Type
Article
Keywords
Air
Breast - pathology
Breast Neoplasms - diagnosis
Europe
Female
Humans
Mammography - instrumentation - methods - standards
Mass Screening - methods
Photons
Radiation Dosage
Radiographic Image Enhancement - methods
Radiographic Image Interpretation, Computer-Assisted - methods
Radiometry - methods
Software
X-Ray Intensifying Screens
X-rays
Abstract
The Sectra MicroDose Mammography system is based on direct photon counting (with a solid-state detector), and a substantially lower dose to the breast than when using conventional systems can be expected. In this work absorbed dose measurements have been performed for the first unit used in routine mammography screening (at the Hospital of Helsingborg, Sweden). Two European protocols on dosimetry in mammography have been followed. Measurement of half value layer (HVL) cannot be performed as prescribed, but this study has demonstrated that non-invasive measurements of HVL can be performed accurately with a sensitive and well collimated solid-state detector with simultaneous correction for the energy dependence. The average glandular dose for a 50 mm standard breast with 50% glandularity, simulated by 45 mm polymethylmethacrylate, was found to be 0.21 and 0.28 mGy in March and December 2004, respectively. These values are much lower than for any other mammography system on the market today. It has to be stressed that the measurements were made using the current clinical settings and that no systematic optimisation of the relationship between absorbed dose and diagnostic image quality has been performed within the present study. In order to further increase the accuracy of absorbed dose measurements for this unit, the existing dose protocols should be revised to account also for the tungsten/aluminium anode/filter combination, the multi-slit pre-collimator device and the occurrence of a dose profile in the scanning direction.
PubMed ID
15933152 View in PubMed
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Clinical and angiographic follow-up after coronary drug-eluting and bare metal stent implantation. Do drug-eluting stents hold the promise?

https://arctichealth.org/en/permalink/ahliterature81244
Source
J Intern Med. 2006 Aug;260(2):118-24
Publication Type
Article
Date
Aug-2006
Author
Jensen J.
Lagerqvist B.
Aasa M.
Särev T.
Nilsson T.
Tornvall P.
Author Affiliation
Department of Cardiology, Karolinska University Hospital, Solna, Stockholm, Sweden. jens.jensen@karolinska.se
Source
J Intern Med. 2006 Aug;260(2):118-24
Date
Aug-2006
Language
English
Publication Type
Article
Keywords
Aged
Angioplasty, Transluminal, Percutaneous Coronary
Coronary Angiography
Coronary Restenosis - mortality - prevention & control - radiography
Coronary Stenosis - mortality - radiography - therapy
Delayed-Action Preparations
Disease-Free Survival
Drug Implants
Female
Follow-Up Studies
Humans
Immunosuppressive Agents - administration & dosage
Male
Metals
Middle Aged
Multivariate Analysis
Radiographic Image Interpretation, Computer-Assisted - methods
Registries
Sirolimus - administration & dosage
Stents
Sweden
Abstract
OBJECTIVES: To investigate the influence of drug-eluting stent (DES) implantation on clinical and angiographic restenosis. DESIGN: Registry study of data from the Swedish Coronary Angiography and Angioplasty Registry with a coronary angiographic substudy. SETTING: Multi-centre study. SUBJECTS: During October 2002 to May 2004 a total of 23 590 percutaneous coronary intervention (PCI) procedures were performed at 25 hospitals. After selection, to achieve comparable groups, a total of 5068 patients of whom 4111 had a bare metal stent (BMS) implanted and 957 had a DES implanted, remained. End-point in the registry follow-up was >50% diameter restenosis at clinically driven reangiography within 12 months after index PCI. The primary end-point in the angiographic substudy was late loss in patients' DES at 6-month angiographic follow-up. RESULTS: The rate of clinically driven restenosis, within 12 months, in patients receiving DES was less (3.9%) compared with those who received BMS (7.0%). In multivariate analysis the risk of clinical restenosis was one-third for DES compared with BMS (HR 0.36, 95% CI 0.25-0.52). In the angiographic substudy late loss was 0.07+/-0.53 mm (range -0.88 to 1.62). The amount of late loss was related to the presence of diabetes mellitus or not (0.19+/-0.45 mm vs. -0.12+/-0.58 mm), and lack of postdilatation of the stent or not (0.23+/-0.51 mm vs. -0.09+/-0.50 mm). CONCLUSIONS: The use of DES in the Swedish 'real world' is effective in reducing the clinically driven restenosis rate, when compared with patients with BMS treatment. In the angiographic follow-up the average late loss was as low as observed in recent randomized multi-centre trials.
PubMed ID
16882275 View in PubMed
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Clinical experience of strain imaging using DENSE for detecting infarcted cardiac segments.

https://arctichealth.org/en/permalink/ahliterature271144
Source
J Cardiovasc Magn Reson. 2015;17:50
Publication Type
Article
Date
2015
Author
Johan Kihlberg
Henrik Haraldsson
Andreas Sigfridsson
Tino Ebbers
Jan E Engvall
Source
J Cardiovasc Magn Reson. 2015;17:50
Date
2015
Language
English
Publication Type
Article
Keywords
Aged
Aged, 80 and over
Area Under Curve
Biomechanical Phenomena
Cicatrix - diagnosis - pathology - physiopathology
Contrast Media
Female
Gadolinium DTPA
Humans
Image Interpretation, Computer-Assisted - methods
Magnetic Resonance Imaging, Cine - methods
Male
Middle Aged
Myocardial Contraction
Myocardial Infarction - diagnosis - pathology - physiopathology
Myocardium - pathology
Predictive value of tests
ROC Curve
Reproducibility of Results
Stress, mechanical
Stroke Volume
Sweden
Ventricular Function, Left
Abstract
We hypothesised that myocardial deformation determined with magnetic resonance imaging (MRI) will detect myocardial scar.
Displacement Encoding with Stimulated Echoes (DENSE) was used to calculate left ventricular strain in 125 patients (29 women and 96 men) with suspected coronary artery disease. The patients also underwent cine imaging and late gadolinium enhancement. 57 patients had a scar area >1% in at least one segment, 23 were considered free from coronary artery disease (control group) and 45 had pathological findings but no scar (mixed group). Peak strain was calculated in eight combinations: radial and circumferential strain in transmural, subendocardial and epicardial layers derived from short axis acquisition, and transmural longitudinal and radial strain derived from long axis acquisitions. In addition, the difference between strain in affected segments and reference segments, "differential strain", from the control group was analysed.
In receiver-operator-characteristic analysis for the detection of 50% transmurality, circumferential strain performed best with area-under-curve (AUC) of 0.94. Using a cut-off value of -17%, sensitivity was 95% at a specificity of 80%. AUC did not further improve with differential strain. There were significant differences between the control group and global strain circumferential direction (-17% versus -12%) and in the longitudinal direction (-13% versus -10%). Interobserver and scan-rescan reproducibility was high with an intraclass correlation coefficient (ICC) >0.93.
DENSE-derived circumferential strain may be used for the detection of myocardial segments with >50 % scar area. The repeatability of strain is satisfactory. DENSE-derived global strain agrees with other global measures of left ventricular ejection fraction.
Notes
Cites: J Magn Reson Imaging. 2013 Mar;37(3):576-9922826177
Cites: Eur J Vasc Endovasc Surg. 2013 Apr;45(4):332-923403219
Cites: Eur Radiol. 2013 May;23(5):1210-723179525
Cites: Int J Cardiovasc Imaging. 2013 Dec;29(8):1779-8623934037
Cites: Scand Cardiovasc J. 2013 Dec;47(6):329-3424295289
Cites: Ann Biomed Eng. 2014 Mar;42(3):541-5424150239
Cites: MAGMA. 1999 Oct;9(1-2):85-9110555178
Cites: Magn Reson Med. 1999 Dec;42(6):1048-6010571926
Cites: Phys Med Biol. 2000 Jun;45(6):1665-8210870717
Cites: Magn Reson Med. 2001 Aug;46(2):324-3411477637
Cites: Magn Reson Med. 2001 Sep;46(3):523-3411550245
Cites: Circulation. 2002 Jan 29;105(4):539-4211815441
Cites: Magn Reson Med. 2004 Apr;51(4):744-5215065247
Cites: Magn Reson Med. 2004 Oct;52(4):774-8115389939
Cites: J Magn Reson. 1999 Mar;137(1):247-5210053155
Cites: J Magn Reson. 1999 Sep;140(1):41-5710479548
Cites: J Magn Reson. 2005 Sep;176(1):99-10615946874
Cites: Scand Cardiovasc J. 2005 Oct;39(5):267-7516269396
Cites: J Cardiovasc Magn Reson. 2005;7(5):775-8216353438
Cites: J Am Soc Echocardiogr. 2005 Dec;18(12):1440-6316376782
Cites: J Nucl Cardiol. 2007 Sep-Oct;14(5):729-4417826327
Cites: Scand J Clin Lab Invest. 2007;67(7):678-9517852799
Cites: Radiology. 2008 Feb;246(2):581-818055873
Cites: J Magn Reson Imaging. 2008 May;27(5):1019-2718425823
Cites: Magn Reson Med. 2009 Apr;61(4):981-819189288
Cites: Cardiovasc Ultrasound. 2009;7:5319917130
Cites: J Am Soc Echocardiogr. 2010 Apr;23(4):351-69; quiz 453-520362924
Cites: Magn Reson Med. 2010 May;63(5):1411-420432313
Cites: Magn Reson Imaging. 2011 Feb;29(2):202-821129876
Cites: Scand J Clin Lab Invest. 2011 May;71(3):232-921391777
Cites: J Cardiovasc Magn Reson. 2011;13:3621798021
Cites: Scand J Urol Nephrol. 2012 Jun;46(3):212-2222250974
Cites: Magn Reson Med. 2012 Jun;67(6):1590-922135133
Cites: Eur Heart J. 2012 Oct;33(19):2451-9622922415
PubMed ID
26104510 View in PubMed
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Comparison of EORTC criteria and PERCIST for PET/CT response evaluation of patients with metastatic colorectal cancer treated with irinotecan and cetuximab.

https://arctichealth.org/en/permalink/ahliterature114857
Source
J Nucl Med. 2013 Jul;54(7):1026-31
Publication Type
Article
Date
Jul-2013
Author
Kristin Skougaard
Dorte Nielsen
Benny Vittrup Jensen
Helle Westergren Hendel
Author Affiliation
Department of Oncology, Copenhagen University Hospital Herlev, Herlev, Denmark. skougaard@dadlnet.dk
Source
J Nucl Med. 2013 Jul;54(7):1026-31
Date
Jul-2013
Language
English
Publication Type
Article
Keywords
Adult
Aged
Aged, 80 and over
Antibodies, Monoclonal, Humanized - administration & dosage
Antineoplastic Combined Chemotherapy Protocols - administration & dosage
Bone Neoplasms - drug therapy - radionuclide imaging - secondary
Camptothecin - administration & dosage - analogs & derivatives
Colorectal Neoplasms - mortality - radionuclide imaging
Denmark - epidemiology
Digestive System Neoplasms - drug therapy - radionuclide imaging - secondary
Female
Fluorodeoxyglucose F18 - diagnostic use
Humans
Image Interpretation, Computer-Assisted - methods
Lung Neoplasms - drug therapy - radionuclide imaging - secondary
Lymphatic Metastasis
Male
Middle Aged
Multimodal Imaging - statistics & numerical data
Outcome Assessment (Health Care) - methods - statistics & numerical data
Positron-Emission Tomography
Prevalence
Radiopharmaceuticals - diagnostic use
Reproducibility of Results
Risk assessment
Sensitivity and specificity
Survival Analysis
Survival Rate
Tomography, X-Ray Computed
Treatment Outcome
Abstract
The study aim was to compare European Organization for Research and Treatment of Cancer (EORTC) criteria with PET Response Criteria in Solid Tumors (PERCIST) for response evaluation of patients with metastatic colorectal cancer treated with a combination of the chemotherapeutic drug irinotecan and the monoclonal antibody cetuximab.
From 2006 to 2009, patients with metastatic colorectal cancer were prospectively included in a phase II trial evaluating the combination of irinotecan and cetuximab every second week, as third-line treatment. (18)F-FDG PET/CT was performed between 1 and 14 d before the first treatment and after every fourth treatment cycle until progression was identified by CT with Response Evaluation Criteria in Solid Tumors (RECIST). Response evaluation with (18)F-FDG PET/CT was retrospectively performed according to both EORTC criteria and PERCIST, classifying the patients into 4 response categories: complete metabolic response (CMR), partial metabolic response (PMR), stable metabolic disease (SMD), and progressive metabolic disease (PMD). Individual best overall metabolic response (BOmR) was registered with both sets of criteria, as well as survival within response categories, and compared.
A total of 61 patients and 203 PET/CT scans were eligible for response evaluation. With EORTC criteria, 38 had PMR, 16 had SMD, and 7 had PMD as their BOmR. With PERCIST, 34 had PMR, 20 had SMD, and 7 had PMD as their BOmR. None of the patients had CMR. There was agreement between EORTC criteria and PERCIST in 87% of the patients, and the corresponding ?-coefficient was 0.76. Disagreements were confined to PMR and SMD. Median overall survival (OS) in months with EORTC criteria was 14.2 in the PMR group and 7.2 in the combined SMD + PMD group. With PERCIST, it was 14.5 in the PMR group and 7.9 in the SMD + PMD group.
Response evaluation with EORTC criteria and PERCIST gave similar responses and OS outcomes with good agreement on BOmR (?-coefficient, 0.76) and similar significant differences in median OS between response groups. Compared with EORTC criteria, we find PERCIST unambiguous because of clear definitions and therefore more straightforward to use.
PubMed ID
23572497 View in PubMed
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50 records – page 1 of 5.