Thousand shades of gray - The role of imaging display in diagnosis of occult scaphoid fractures - A pilot study

Introduction

Most hospitals and clinics utilize commercial grade displays for viewing wrist radiographs. There is no evidence regarding the role of the imaging display used to evaluate the radiographs. The aim of this study was to compare the rates of scaphoid fracture diagnosis by commercial grade and medical grade displays.

Methods

Wrist radiographs of patients that had clinical signs of scaphoid fracture without findings on plain radiography (suspected scaphoid fractures) were retrospectively collected from ER department and interpreted for radiographic signs of fracture by four orthopedics seniors commercial grade and medical grade displays. The difference in fracture diagnosis rates were studied. Inter- and intra-observer variability were also studied.

Results

Study population comprised of 175 high quality wrist radiographs were interpreted. Mean 48.25 (27%) scaphoid fractures were observed on commercial grade display compared to 66 (38.2%) on medical grade display (p = 0.076). The total inter-observer agreement could be defined as a moderate agreement (κ = 0.527, Accuracy = 0.77). Total agreement between all observers were observed in 86 (49.1%) cases compared to 89 (50.9%) cases when reviewing X-rays on commercial and medical displays, respectively.

Discussion

The scaphoid fracture detection rate on medical grade display was not statistically higher compared to non-medical grade displays, but we did find a tendency toward medical grade display. We found that in a substantial number of cases, our observers recognize signs of fracture that were initially evaluated as "suspected fracture" by the ER physicians. As a pilot study, we found evidence that support the need for a prospective study designed to compare the observations to a gold standard modality, such as MRI. We believe utilizing medical grade displays can increase the rate of diagnosis in cases of clinically suspected scaphoid fractures and better manage the clinical scenario of a suspected scaphoid fracture.

Impact of viewing conditions on the performance assessment of different computer monitors used for dental diagnostics

Purpose

This study aimed to assess the computer monitors used for analysis and interpretation of digital radiographs within the clinics of the Oral Health Centre of Western Australia.

Materials and Methods

In total, 135 computer monitors (3 brands, 6 models) were assessed by analysing the same radiographic image of a combined 13-step aluminium step wedge and the Artinis CDDent 1.0® (Artinis Medical Systems B.V.®, Elst, the Netherlands) test object. The number of steps and cylindrical objects observed on each monitor was recorded along with the monitor's make, model, position relative to the researcher's eye level, and proximity to the nearest window. The number of window panels blocked by blinds, the outside weather conditions, and the number of ceiling lights over the surgical suite/cubicle were also recorded. MedCalc® version 19.2.1 (MedCalc Software Ltd®, Ostend, Belgium, https://www.medcalc.org; 2020) was used for statistical analyses (Kruskal-Wallis test and stepwise regression analysis). The level of significance was set at P<0.05.

Results

Stepwise regression analysis showed that only the monitor brand and proximity of the monitor to a window had a significant impact on the monitor's performance (P<0.05). The Kruskal-Wallis test showed significant differences (P<0.05) in monitor performance for all variables investigated, except for the weather and the clinic in which the monitors were placed.

Conclusion

The vast performance variation present between computer monitors implies the need for a review of monitor selection, calibration, and viewing conditions.

Reduction of visual acuity decreases capacity to evaluate radiographic image quality

INTRODUCTION

To determine the impact of reduced visual acuity on the evaluation of a test object and appendicular radiographs.

METHODS

Visual acuity was reduced by two different magnitudes using simulation glasses and compared to normal vision (no glasses). During phase one phantom images were produced for the purpose of counting objects by 13 observers and on phase 2 image appraisal of anatomical structures was performed on anonymized radiographic images by 7 observers. The monitors were calibrated (SMPTE RP133 test pattern) and the room lighting was maintained at 7 ± 1 lux. Image display and data on grading were managed using ViewDEX (v.2.0) and the area under the visual grading characteristic (AUC_VGC) was calculated using VGC Analyzer (v1.0.2). Inferential statistics were calculated using SPSS.

RESULTS

For the evaluation of appendicular radiographs the total interpretation time was longer when visual acuity was reduced with 2 pairs of simulation glasses (15.4 versus 8.9 min). Visual grading analysis showed that observers can lose the ability to detect anatomical and contrast differences when they have a simulated visual acuity reduction, being more challenging to differentiate low contrast details. No simulation glasses, compared to 1 pair gives an AUC_VGC of 0.302 (0.280, 0.333), that decreases to 0.197 (0.175, 0.223) when using 2 pairs of glasses.

CONCLUSIONS

Reduced visual acuity has a significant negative impact on the evaluation of test objects and clinical images. Further work is required to test the impact of reduced visual acuity on visual search, technical evaluation of a wider range of images as well as pathology detection/characterization performance.

IMPLICATIONS FOR PRACTICE

It seems that visual performance needs to be considered to reduce the risks associated with incomplete or incorrect diagnosis. If employers or professional bodies were to introduce regular eye tests into health screening it may reduce the risk of misinterpretation as a result of poor vision.

An Evaluation of Performance Characteristics of Primary Display Devices

The aim of this study was to complete a full evaluation of the new EIZO RX850 liquid crystal display and compare it to two currently used medical displays in Australia (EIZO GS510 and Barco MDCG 5121). The American Association of Physicists in Medicine (AAPM) Task Group 18 Quality Control test pattern was used to assess the performance of three high-resolution primary medical displays: EIZO RX850, EIZO GS510, and Barco MDCG 5121. A Konica Minolta spectroradiometer (CS-2000) was used to assess luminance response, non-uniformity, veiling glare, and color uniformity. Qualitative evaluation of noise was also performed. Seven breast lesions were displayed on each monitor and photographed with a calibrated 5.5-MP Olympus E-1 digital SLR camera. ImageJ software was used to sample pixel information from each lesion and surrounding background to calculate their conspicuity index on each of the displays. All monitor fulfilled all AAPM acceptance criteria. The performance characteristics for EIZO RX850, Barco MDCG 5121, and EIZO GS510 respectively were as follows: maximum luminance (490, 500.5, and 413 cd/m(2)), minimum luminance (0.724, 1.170, and 0.92 cd/m(2)), contrast ratio (675:1, 428:1, 449:1), just-noticeable difference index (635, 622, 609), non-uniformity (20, 5.92, and 8.5 %), veiling glare (GR = 2465.6, 720.4, 1249.8), and color uniformity (Δu'v' = +0.003, +0.002, +0.002). All monitors demonstrated low noise levels. The conspicuity index (χ) of the lesions was slightly higher in the EIZO RX850 display. All medical displays fulfilled AAPM performance criteria, and performance characteristics of EIZO RX850 are equal to or better than those of the Barco MDCG 5121 and EIZO GS510 displays.

Improved parenchymal liver enhancement with extended delay on Gd-EOB-DTPA-enhanced MRI in patients with parenchymal liver disease: associated clinical and imaging factors

AIM

To establish the effect of prolonged hepatobiliary phase (HBP) delay time on hepatic enhancement in patients with parenchymal liver disease (PLD).

MATERIALS AND METHODS

Gadoxetate disodium (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) examinations with HBP were obtained after 20- (HBP-20) and 30-minute (HBP-30) delays in patients with PLD. For each patient, the Model for End-Stage Liver Disease (MELD) score, total and direct bilirubin, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), prothrombin time (PT), and partial thromboplastin time (PTT) were recorded. Signal intensities of the liver, main portal vein, and spleen on pre-contrast, HBP-20, and HBP-30 were documented. Signal intensities were used to calculate liver relative enhancement (LRE), liver-spleen index (LSI), and liver-portal vein index (LPI) for HBP-20 and HBP-30. Improved hepatic enhancement was considered if two or more indices were higher on HBP-30 than HBP-20. A logistic regression model was constructed with improved hepatic enhancement as the outcome.

RESULTS

One hundred and twenty-nine patients underwent 142 MRIs. Mean LRE, LSI, and LPI each increased from HBP-20 to HBP-30 (p = 0.004, p < 0.001, and p < 0.001, respectively). Seventy-two point five percent of cases demonstrated improved hepatic enhancement. The odds ratios for improved hepatic enhancement were 0.85 for MELD score (p = 0.02) and 3.2 for the 3 T scanner (p = 0.02), adjusted for age and sex.

CONCLUSION

Increasing HBP delay to 30 minutes improves hepatic enhancement in patients with PLD, particularly if using a 3 T scanner. This effect is attenuated with higher MELD scores.

Could standardizing "commercial off-the-shelf" (COTS) monitors to the DICOM part 14: GSDF improve the presentation of dental images? A visual grading characteristics analysis

OBJECTIVES

To investigate whether standardizing commercial off-the-shelf (COTS) display devices to the digital imaging and communications in medicine part 14: greyscale standard display function (DICOM part 14: GSDF) would affect the presentation of dental images.

METHODS

Two COTS display devices from the radiology department of a dental teaching hospital and a laptop computer monitor for reference were calibrated to conform to DICOM part 14: GSDF. Four dental surgeons and two final-year students undertook a relative visual grading analysis of the two devices before and after calibration, under control of the viewing environment.

RESULTS

Calibrating COTS display devices to conform to the DICOM part 14: GSDF and viewing under reduced ambient light result in a consistent, perceived visual sensation for the presented radiological image. The area under the visual grading characteristics curve (AUCVGC) before calibration is 0.62 CI (0.56, 0.68) and AUCVGC after calibration is 0.51 CI (0.45, 0.57).

CONCLUSIONS

Standardizing COTS display devices to the DICOM part 14: GSDF can improve image presentation.

Observer performance using virtual pathology slides: impact of LCD color reproduction accuracy

The use of color LCDs in medical imaging is growing as more clinical specialties use digital images as a resource in diagnosis and treatment decisions. Telemedicine applications such as telepathology, teledermatology, and teleophthalmology rely heavily on color images. However, standard methods for calibrating, characterizing, and profiling color displays do not exist, resulting in inconsistent presentation. To address this, we developed a calibration, characterization, and profiling protocol for color-critical medical imaging applications. Physical characterization of displays calibrated with and without the protocol revealed high color reproduction accuracy with the protocol. The present study assessed the impact of this protocol on observer performance. A set of 250 breast biopsy virtual slide regions of interest (half malignant, half benign) were shown to six pathologists, once using the calibration protocol and once using the same display in its "native" off-the-shelf uncalibrated state. Diagnostic accuracy and time to render a decision were measured. In terms of ROC performance, Az (area under the curve) calibrated = 0.8570 and Az uncalibrated = 0.8488. No statistically significant difference (p = 0.4112) was observed. In terms of interpretation speed, mean calibrated = 4.895 s; mean uncalibrated = 6.304 s which is statistically significant (p = 0.0460). Early results suggest a slight advantage diagnostically for a properly calibrated and color-managed display and a significant potential advantage in terms of improved workflow. Future work should be conducted using different types of color images that may be more dependent on accurate color rendering and a wider range of LCDs with varying characteristics.

Flexible image evaluation: iPad versus secondary-class monitors for review of MR spinal emergency cases, a comparative study

RATIONALE AND OBJECTIVES

Studies have highlighted the potential of handheld viewing devices for rapid diagnosis and increased smartphone usage among physicians and radiologists is known as is the clinical applicability of hand-held devices for computed tomography (CT) spinal injury cases. Magnetic resonance (MR), however, is the accepted gold standard for spinal imaging, providing visualization of both ligament and spinal cord pathology. This study investigated the diagnostic accuracy of the iPad, the most probable alternative display device outside the radiology environment and financially viable alternative, when reviewing emergency spinal MR images, in comparison with secondary-class LCD devices in the case of the interpretation of CT and MR imaging examinations.

MATERIALS AND METHODS

In total 31 MR cases including both positives (n = 13) containing one of four possible presentations: spinal cord compression, cauda equine syndrome, spinal cord hemorrhage, or spinal cord edema and controls (n = 18) were reviewed. Ziltron iPad software facilitated the display of cases and the receiver operating characteristic (ROC) analysis. Thirteen American Board of Radiology board-certified radiologists reviewed all cases on both displays. Standardized viewing conditions were maintained.

RESULTS

Dorfman-Berbaum-Metz multireader-multicase (DBM MRMC) analysis was performed including random readers/random cases, fixed readers/random cases and random readers/fixed cases. No differences of statistical significance (P ≤ .05) could be found in terms of area under the curve, sensitivity and specificity between the iPad and secondary-class display.

CONCLUSION

The iPad performed with equal diagnostic accuracy when compared with the secondary-class LCD device after DBM MRMC analysis, demonstrating the iPad as an option to aid initial review of MR spinal emergency cases.