Mark F McEntee | University Of Sydney (original) (raw)

Papers by Mark F McEntee

Journal of Medical Imaging and Radiation Sciences, 2016

The aim of this study is to compare mammographic breast density assessment with automated volumet... more The aim of this study is to compare mammographic breast density assessment with automated volumetric software with Breast Imaging Reporting and Data System (BIRADS) categorization by radiologists on two imaging systems. A data set of 120 mammograms was classified by twenty American Board of Radiology (ABR) Examiners. The mammograms were of 20 women (mean age, 60 years; range, 42-89 years). These women were image twice one year apart either on GE system or Hologic system. These images also had their volumetric density classified by using Volpara Density Grade (VDG). The radiologists were asked to estimate the mammographic density according to BIRADS categories (1-4). There was a moderate agreement between VDG classification and radiologist BIRADS density shown with Cohen's Kappa (κ=0.45; p<0.001). Radiologists estimated percentage density to be lower by an average of 0.37 for the Hologic system, the radiologist's BIRADS having a mean of 2.05 and the mean VDG higher at 2.42(t= -8.88; p<0.001). VDG and radiologist's BIRADS showed a positive strong correlation (r=0.87; p<0.001). Radiologist BIRADS and VDG AvBD% also showed a strong positive correlation (r=0.86; p<0.001). There was a large spread of radiologist's BIRADS categories for each of the VDG AvBD% classifications.Using Volpara, the Hologic system showed a lower mean AvBD% (9.5 vs. 9.6). However using BIRADS the Hologic systems showed a lower mean (2.05 vs. 2.22). Automated systems demonstrated higher internal validity. The results demonstrated a moderate agreement and a strong correlation between VDG classification and radiologist BIRADS density assessment.

Medical Imaging 2016: Image Perception, Observer Performance, and Technology Assessment, 2016

Medical Imaging 2014: Image Perception, Observer Performance, and Technology Assessment, 2014

ABSTRACT The aim of this study is to compare mammographic breast density assessment with automate... more ABSTRACT The aim of this study is to compare mammographic breast density assessment with automated volumetric software with Breast Imaging Reporting and Data System (BIRADS) categorization by radiologists on two imaging systems. A data set of 120 mammograms was classified by twenty American Board of Radiology (ABR) Examiners. The mammograms were of 20 women (mean age, 60 years; range, 42–89 years). These women were image twice once with GE system and the following year with Hologic system. These images also had their volumetric density classified by using Volpara Density Grade (VDG). The radiologists were asked to estimate the mammographic density according to BIRADS categories (1- 4). There was a moderate agreement between VDG classification and radiologist BIRADS density shown with Cohen’s Kappa (K=0.45; p<0.001). Radiologists estimated percentage density to be lower by an average of 0.37, the radiologist’s BIRADS having a mean of 2.13 and the mean VDG higher at 2.50 (t = -11.99; p<0.001). VDG and radiologist’s BIRADS showed a positive strong correlation (r=0.84; p<0.001). Radiologist BIRADS and VDG AvBD% also showed a strong positive correlation (r=0.86; p<0.001). There was a large spread of radiologist’s BIRADS categories for each of the VDG AvBD% classifications. Using Volpara, the Hologic system showed a higher meanAvBD% (10.02 vs. 9.97). However using BIRADS the Hologic systems showed a lower mean (2.05 vs. 2.21). Automated systems demonstrated higher internal validity. The results demonstrated a moderate agreement and a strong correlation between VDG classification and radiologist BIRADS density assessment. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Academic Radiology, 2015

To investigate agreement on mammographic breast density (MD) assessment between automated volumet... more To investigate agreement on mammographic breast density (MD) assessment between automated volumetric software and Breast Imaging Reporting and Data System (BIRADS) categorization by expert radiologists. Forty cases of left craniocaudal and mediolateral oblique mammograms from 20 women were used. All images had their volumetric density classified using Volpara density grade (VDG) and average volumetric breast density percentage. The same images were then classified into BIRADS categories (I-IV) by 20 American Board of Radiology examiners. The results demonstrated a moderate agreement (κ = 0.537; 95% CI = 0.234-0.699) between VDG classification and radiologists&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;#39; BIRADS density assessment. Interreader agreement using BIRADS also demonstrated moderate agreement (κ = 0.565; 95% CI = 0.519-0.610) ranging from 0.328 to 0.669. Radiologists&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;#39; average BIRADS was lower than average VDG scores by 0.33, with their mean being 2.13, whereas the mean VDG was 2.48 (U = -3.742; 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;lt; 0.001). VDG and BIRADS showed a very strong positive correlation (ρ = 0.91; 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;lt; 0.001) as did BIRADS and average volumetric breast density percentage (ρ = 0.94; 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;lt; 0.001). Automated volumetric breast density assessment shows moderate agreement and very strong correlation with BIRADS; interreader variations still exist within BIRADS. Because of the increasing importance of MD measurement in clinical management of patients, widely accepted, reproducible, and accurate measures of MD are required.

Journal of Medical Imaging and Radiation Oncology, 2016

The aim of this study was to evaluate observer variability in mammographic density assessment as ... more The aim of this study was to evaluate observer variability in mammographic density assessment as measured using the Royal Australian and New Zealand College of Radiologists (RANZCR) synoptic scales. Visual assessment of mammographic density by radiologists is commonly used in clinical practice; however, these assessments have been shown to be more subjective than quantitative methods. The study included 40 cases of left cranial-caudal (CC) and mediolateral oblique (MLO) radiographs from 20 women. RANZCR-registered radiologists (n = 26) estimated mammographic breast density of the same images according to RANZCR synoptic scales 1-4. All images had their volumetric density classified using Volpara Density Grade (VDG) and Average Volumetric Breast Density percentage (AvBD%). The results showed that the radiologists sampled had specialized for 17.18 years (sd 12.03) and read 2072 (sd 2441) mammograms per year on average. Inter-observer agreement using RANZCR synoptic scales had an average Kappa of 0.360; (95% CI = 0.308-0.412) and a range of 0.078-0.499. Radiologists estimated percentage density was lower by 0.37 than VDG, with their mean being 2.18 and the mean VDG was 2.55 (Z = -3.873; P < 0.001). VDG and RANZCR showed a positive strong correlation (ρ = 0.898; P < 0.001). AvBD% and RANZCR also showed a positive strong correlation (ρ = 0.904; P < 0.001). The inter-observer agreement with RANZCR synoptic scales was fair. Wide inter-observer variability was observed. Continued research on appropriate assessment methods for mammographic density assessment is required to avoid unnecessary variations.

Journal of Medical Imaging, 2015

Mammographic density (MD) is a significant risk factor for breast cancer and has been shown to re... more Mammographic density (MD) is a significant risk factor for breast cancer and has been shown to reduce the sensitivity of mammography screening. Knowledge of a woman's density can be used to predict her risk of developing breast cancer and personalize her imaging pathway. However, measurement of breast density has proven to be troublesome with wide variations in density recorded using radiologists' visual Breast Imaging Reporting and Data System (BIRADS). Several automated methods for assessing breast density have been proposed, each with their own source of measurement error. The use of differing mammographic imaging systems further complicates MD measurement, especially for the same women imaged over time. The purpose of this study was to investigate whether having a mammogram on differing manufacturer's equipment affects a woman's MD measurement. Raw mammographic images were acquired on two mammography imaging systems (General Electric and Hologic) one year apart and processed using VolparaDensity™ to obtain the Volpara Density Grade (VDG) and average volumetric breast density percentage (AvBD%). Visual BIRADS scores were also obtained from 20 expert readers. BIRADS scores for both systems showed strong positive correlation (ρ ¼ 0.904; p < 0.001), while the VDG (ρ ¼ 0.978; p < 0.001) and AvBD% (ρ ¼ 0.973; p < 0.001) showed stronger positive correlations. Substantial agreement was shown between the systems for BIRADS (κ ¼ 0.692; p < 0.001), however, the systems demonstrated an almost perfect agreement for VDG (κ ¼ 0.933; p < 0.001). Damases, Brennan, and McEntee: Mammographic density measurements are not affected. . . Downloaded From: http://medicalimaging.spiedigitallibrary.org/ on 03/08/2015 Terms of Use: http://spiedl.org/terms Damases, Brennan, and McEntee: Mammographic density measurements are not affected. . . Downloaded From: http://medicalimaging.spiedigitallibrary.org/ on 03/08/2015 Terms of Use: http://spiedl.org/terms 5 Conclusion Stronger positive correlations in VDG and AvBD% scores compared with BIRADS values were demonstrated between Damases, Brennan, and McEntee: Mammographic density measurements are not affected. . . Downloaded From: http://medicalimaging.spiedigitallibrary.org/ on 03/08/2015 Terms of Use: http://spiedl.org/terms

Medical Imaging 2015: Image Perception, Observer Performance, and Technology Assessment, 2015

The purpose of this study is to investigate whether having a mammogram on differing manufacturer ... more The purpose of this study is to investigate whether having a mammogram on differing manufacturer equipment will affect a woman's breast density (BD) measurement. The data set comprised of 40 cases, each containing a combined image of the left craniocaudal (LCC) and left mediolateral oblique (LMLO). These images were obtained from 20 women age between 42-89 years. The images were acquired on two imaging systems (GE and Hologic) one year apart. Volumetric BD was assessed by using Volpara Density Grade (VDG) and average BD% (AvBD%). Twenty American Board of Radiology (ABR) examiners assessed the same images using the BIRADS BD scale 1-4. Statistical comparisons were performed on the means using Mann-Whitney, on correlation using Spearman's rank coefficient of correlation and agreement using Cohen's Kappa. The absolute median BIRADS difference between GE and Hologic was 0.225 (2.00 versus 2.00; p<0.043). The VDG measures for GE was not statistically different to Hologic (2.00 versus 2.00; p<0.877), likewise the median AvBD% for the GE and Hologic systems showed no difference (6.51 versus 6.79; p<0.935). BIRADS for GE and Hologic systems showed strong positive correlation (ρ=0.904; p<0.001), while the VDG (ρ=0.978; p<0.001) and AvBD% (ρ=0.973; p<0.001) showed very strong positive correlations. There was a substantial agreement between GE and Hologic systems for BIRADS density shown with Cohen's Kappa (κ=0.692; p<0.001), however the systems demonstrated an almost perfect agreement for VDG (κ=0.933; p<0.001). Downloaded From: http://proceedings.spiedigitallibrary.org/ on 03/24/2015 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 9416 94160A-3 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 03/24/2015 Terms of Use: http://spiedl.org/terms The systems showed very strong positive correlation (ρ=0.978; p<0.001). Proc. of SPIE Vol. 9416 94160A-5 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 03/24/2015 Terms of Use: http://spiedl.org/terms

Any information contained in this pdf file is automatically generated from digital material submi... more Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to third-party sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expe...

Pediatric Radiology, 2015

The volume of CT examinations has increased with resultant increases in collective dose values ov... more The volume of CT examinations has increased with resultant increases in collective dose values over the last decade. To analyze the impact of the tube current and voltage modulation for dose values and image quality of pediatric head CT examinations. Head CT examinations were performed on anthropomorphic phantoms and four pediatric age categories before and after the introduction of dedicated pediatric curves for tube voltage and current modulation. Local diagnostic reference levels were calculated. Visual grading characteristic image quality evaluation was performed by four pediatric neuroradiologists and image noise comparisons were performed. Pediatric-specific modulation curves demonstrated a 49% decrease in mean radiation dose for phantom examinations. The local diagnostic reference levels (CTDIvol) for clinical examinations decreased by 52%, 41%, 46% and 40% for newborn, 5-, 10- and 15-year-old patients, respectively. Visual grading characteristic image quality was maintained for the majority of age categorizations (area under the curve = 0.5) and image noise measurements did not change (P = 0.693). Pediatric-specific dose modulation curves resulted in an overall mean dose reduction of 45% with no significant differences in subjective or objective image quality findings.

British Journal of Radiology, 2012

Objective: To propose Irish CT diagnostic reference levels (DRLs) by collecting radiation doses f... more Objective: To propose Irish CT diagnostic reference levels (DRLs) by collecting radiation doses for the most commonly performed CT examinations. Methods: A pilot study investigated the most frequent CT examinations. 40 CT sites were then asked to complete a survey booklet to allow the recording of CT parameters for each of 9 CT examinations during a 12-week period. Dose data [CT volume index (CTDI vol ) and dose-length product (DLP)] on a minimum of 10 average-sized patients in each category were recorded to calculate a mean site CTDI vol and DLP value. The rounded 75th percentile was used to calculate a DRL for each site and the country by compiling all results. Results are compared with international DRL data. Results: Data were collected for 3305 patients. 30 sites responded with data for 34 scanners, representing 54% of the national total. All equipment had multislice capability (2-128 slices). DRLs are proposed using CTDI vol (mGy) and DLP (mGy cm) for CT head (66/58 and 940, respectively), sinuses (16 and 210, respectively), cervical spine (19 and 420, respectively), thorax (9/11 and 390, respectively), high resolution CT (7 and 280, respectively), CT pulmonary angiography (13 and 430, respectively), multiphase abdomen (13 and 1120, respectively), routine abdomen/pelvis (12 and 600, respectively) and trunk examinations (10/12 and 850, respectively). These values are lower than current DRLs and comparable to other international studies. Wide variations in mean doses are noted across sites. Conclusions: Baseline figures for Irish CT DRLs are provided on the most frequently performed CT examinations. The variations in dose between CT departments as well as between identical scanners suggest a large potential for optimisation of examinations.

$Research paper thumbnail of The effect of compression on confidence during the detection of skull fractures in CT$

As part of a study to establish whether detection of cranial vault fractures is affected by JPEG ... more As part of a study to establish whether detection of cranial vault fractures is affected by JPEG 2000 30:1 and 60:1 lossy compression when compared to JPEG 2000 lossless compression we looked at the effects on confidence ratings 55 CT images, with three levels of JPEG 2000 compression (lossless, 30:1 & 60:1) were presented to 14 senior radiologists, 12 from the American Board of Radiology and 2 form Australia, 7 of whom were MSK specialists and 7 were neuroradiologists. 32 Images contained a single skull fracture while 23 were normal. Images were displayed on one calibrated, secondary LCD, in an ambient lighting of 32.2 lux. Observers were asked to identify the presence or absence of a fracture and where a fracture was present to locate and rate their confidence in its presence. A jack-knifed alternate free-response receiver operating characteristic (JAFROC) and a ROC methodology was employed and the DBM MRMC and ANOVA were used to explore differences between the lossless and lossy compressed images. A significant trend of increased confidence in true and false positive scores was seen with JPEG2000 Lossy 60:1 compression. An ANOVA on the mean confidence rating obtained for correct (TP) and incorrect (FP) localization skull fractions demonstrated that this was a significant difference between lossless and 60:1 [FP, p<0.001; TP, p<0.014] and 30:1 and 60:1 [FP, p<0.014; TP, p<0.037].

$Research paper thumbnail of The effect of JPEG2000 compression on detection of skull fractures in CT$

Rational and Objectives: To investigate the effect of the Joint Photographic Experts Group (JPEG2... more Rational and Objectives: To investigate the effect of the Joint Photographic Experts Group (JPEG2000) 30:1 and 60:1 lossy compression on the detection of cranial vault fractures when compared to JPEG2000 lossless compression. Materials and Methods: Fifty cranial computed tomography (CT) images were processed with three different level of JPEG2000 compression (lossless, 30:1 lossy, and 60:1 lossy) creating three sets of images. These were presented to five musculoskeletal specialists and five neuroradiologists. Each reader read at two of the three compression levels. Twenty-two cases contained a single fracture; the remaining 28 cases contained no fractures. Observers were asked to identify the presence or absence of a fracture, to locate its site, and rate their degree of confidence. Receiver operating characteristic (ROC), jackknife free-response receiver operating characteristic (JAFROC) and the Dorfman-Berbaum-Metz multiple reader multiple case (DBM-MRMC) analyses were used to ex...

Academic radiology, Jan 26, 2015

Three diagnostic performance test for the evaluation of image quality have been identified, a pre... more Three diagnostic performance test for the evaluation of image quality have been identified, a preference method, comparative grading and an evaluation of anatomical quality criteria. This study examines which of these is most effective. Softcopy chest radiographs acquired using two photostimulable phosphor systems (Agfa ADC and Kodak KESPR) have been evaluated using all three diagnostic performance tests.