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.
There has been much debate in recent years surrounding the application of handheld devices such as personal digital assistants (PDAs), smartphones, and more recently the Apple iPad, in health care. The potential applications for such devices and their utility in medicine is clear with studies in 2003 and 2005 suggesting that 46% of nonradiology attending physicians and trainees in one tertiary care academic medical center and approximately 45% of randomly selected active and training radiologists who were members of the Radiological Society of North America were using PDAs . Aside from scheduling and calendar applications, the nonradiology physicians used their devices for accessing drug information programs, medical references, and medical calculators. In the 2005 study, only 24.6% of surveyed radiologists had a radiology application installed on their devices, whereas many remained skeptical about the potential utility for PDAs to be used to view entire imaging studies directly from a picture archiving and communication system (PACS) . The radiologists identified memory capacity, software availability, and screen resolution as the important factors influencing any decision to purchase a PDA. There is much anecdotal evidence to suggest that the usage rates amongst physicians and radiologists is much greater following ongoing developments in smartphone technology, along with the introduction of the iPhone and iPad . Since its launch in April 2010, the iPad itself has generated significant interest in terms of its role in medicine and its potential application for the display of radiological images.
Although these devices are used in modern medicine as outlined, the iPad with its larger display size and superior contrast ratio to other handheld devices warrants closer investigation in terms of its utility in radiology. Many of the other previously identified limitations of handheld devices such as user interface, inherently low resolution, poor connectivity, slow data transfer, available software, processor speed, memory, data security, and Digital Imaging and Communications in Medicine (DICOM) compatibility have now been overcome or have at least progressed . According to these studies, the consensus is that such handheld devices have the greatest potential in terms of accessing radiological images remote to the radiology department or indeed remote to the institution for initial review purposes and can be used to discern primary pathologies but should not be used to help prepare radiological reports. The application of such technology to primary diagnosis of emergency radiology examinations has been explored by several authors for a range of clinical scenarios and handheld technologies. Toomey at al have explored the use of PDAs and the iTouch for detection of orthopaedic fractures on radiographs and intracranial hemorrhage on computed tomography (CT) , Choudhri et al have undertaken some preliminary work exploring the utility of the iPhone for the review of abdominal CT for the evaluation of acute appendicitis , whereas Rosenberg explored the impact of reviewing CT brain examinations for the neurosurgical triage of patients .
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Materials and methods
Overview
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Equipment
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Table 1
Comparison of the Two Display Devices Used for the Study
Specification Type ViewSonic (VP201m) iPad Maximum luminance ∗ 157 cdm −2 300.1 cdm −2 Minimum luminance ∗ 0.4 cdm −2 0.45 cdm −2 Contrast ratio ∗ 392:1 667:1 Display resolutions 1200 × 1600 pixels 1024 × 768 pixels Screen type LCD LED backlit Screen size (in) 20.1 (51.0) 9.7 (24.3) Interaction method Mouse Multitouch touchscreen
LCD, liquid crystal display; LED, light-emitting diode.
Values in parentheses are centimeters.
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Images
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Software
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Observers
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Table 2
Binormal (Dorfman-Berbaum-Metz Multireader-Multicase) and Empirical/Trapezoidal (Ziltron) Area under the Receiver Operating Characteristic Curve, Sensitivity and Specificity Scores and Difference for all Readers
Reader iPad ViewSonic VP201m AUC (Binormal) AUC (Empirical) Sensitivity Specificity AUC (Binormal) AUC (Empirical) Sensitivity Specificity AUC Difference (Binormal) 1 m 0.943 0.91 0.92 0.72 0.890 0.86 0.85 0.67 −0.053 2 m 0.843 0.82 0.85 0.72 0.907 0.89 0.92 0.89 0.064 3 i 0.844 0.82 0.62 0.83 0.886 0.86 0.85 0.83 0.042 4 m 0.921 0.89 0.85 0.78 0.870 0.85 0.85 0.67 −0.051 5 i 0.902 0.90 0.85 0.89 0.867 0.85 0.62 0.94 −0.035 6 m 0.870 0.85 0.77 0.67 0.809 0.78 0.85 0.61 −0.061 7 i 0.895 0.83 0.92 0.67 0.926 0.87 0.92 0.78 0.031 8 m 0.950 0.92 0.92 0.89 0.933 0.90 0.77 0.89 −0.017 9 m 0.893 0.75 0.85 0.56 0.863 0.83 0.92 0.56 −0.030 10 m 0.874 0.82 0.85 0.72 0.877 0.81 0.77 0.83 0.003 11 i 0.689 0.75 0.77 0.72 0.861 0.86 0.62 0.89 0.172 12 i 0.938 0.91 1.0 0.67 0.887 0.85 0.85 0.83 −0.051 13 i 0.852 0.77 0.77 0.78 0.950 0.88 0.92 0.83 0.098 Mean 0.878 (0.0675) 0.842 (0.061) 0.842 (0.095) 0.740 (0.094) 0.887 (0.0367) 0.853 (0.032) 0.824 (0.104) 0.786 (0.120) 0.009 (0.070)
AUC, area under the curve.
Subscript indicates which display device was used for first viewing (m = monitor; i = iPad).
Analysis of variance empirical AUC: P = .55, sensitivity P = .654, specificity P = .285.
*Standard deviations shown in parentheses.
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Statistical Analysis
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Results
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Table 3
Results of Dorfman-Berbaum-Metz Multireader-Multicase Analysis
Analysis 95% Confidence Intervals_F__P_ IPad (Mean AUC = 0.878) ViewSonic VP201m (Mean AUC = 0.887) Difference (Mean AUC = −0.009) Random readers and cases (0.785–0.972) (0.791–0.982) (−0.051 to 0.034) 0.19 .6696 Fixed readers, random cases (0.783–0.973) (0.786–0.988) (−0.041 to 0.023) 0.29 .5961 Random readers, fixed cases (0.837–0.919) (0.865–0.909) (−0.051 to 0.034) 0.19 .6696
AUC, area under the curve.
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Sensitivity and Specificity
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Discussion
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Conclusion
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Acknowledgments
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