Spatial Resolution Requirements in Digital Radiography of Scaphoid Fractures

Jónsson, Ásbjörn; Laurin, S; Karner, Göran; Herrlin, Kristian; Hochbergs, P.; Jonsson, K.; Rudling, O.; Sandström, Staffan; Sloth, M.; Svahn, G.; Pettersson, Holger

doi:10.1177/02841851960373p226

Cited by 11 publications

(2 citation statements)

References 23 publications

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“…Observational and experimental studies on lesion detectability as a function of pixel size abound in the literature. [1][2][3][4][5][6][7][8][9] Typically, these studies involve human detection of a specific type of lesion from images acquired with different pixel sizes. These studies then utilize some form of receiver operating characteristic curve ͑ROC͒ 10 analysis to demonstrate lesion detectability as a function of pixel size.…”

Section: Introductionmentioning

confidence: 99%

A lesion detectability simulation method for digital x‐ray imaging

2000

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A simulation method is described in this work that aids in quantifying the upper limits of lesion detectability as a function of lesion size, lesion contrast, pixel size, and x-ray exposure for digital x-ray imaging systems. The method entails random lesion placement with subsequent simulated imaging on idealized x-ray detectors with no additive noise and 100% quantum detective efficiency. Lesions of different size and thickness were simulated. Mean (expectation) lesion signal-to-noise ratios (LSNRs) were calculated and receiver operating characteristic (ROC) curves were constructed based on LSNR ensembles. Mean (expectation) values of the areas under the ROC curves were calculated for lesions of varying size on pixel arrays of varying size at different exposures. Analyses were performed across several parameters, including lesion size, pixel size, and exposure levels representative of various areas of radiography. As expected, lesion detectability increased with lesion size, contrast, pixel size, and exposure. The model suggests that lesion detectability is strongly dependent on the relative alignment (phase) of the lesion with the pixel matrix for lesions on the order of the pixel size.

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Section: Introductionmentioning

confidence: 99%

A lesion detectability simulation method for digital x‐ray imaging

2000

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“…Radiography is a cheap and widely used primary imaging technique in the diagnosis of clinically suspected scaphoid fractures (3,7,9,20,22). However, several reports conclude that initial and follow-up conventional radiographs are not reliable for the detection of scaphoid fractures (22,24).…”

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confidence: 99%

Modified carpal box technique in the diagnosis of suspected scaphoid fractures

Toth¹,

Mester²,

Cseh³

et al. 2003

Acta Radiol

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Diagnostic accuracy of film-based, TIFF, and wavelet compressed digital temporomandibular joint images

et al. 2000

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The purpose of this research was to determine if digitization and the application of various compression routines to digital images of temporomandibular joint (TMJ) radiographs would diminish observer accuracy in the detection of specific osseous characteristics associated with TMJ degenerative joint disease (DJD). Nine observers viewed 6 cropped hard-copy radiographic films each of 34 TMJs (17 radiographic series). Regions of interest measuring 2 in x 2 in were digitized using an 8-bit scanner with transparency adapter at 300 dpi. The images were placed into a montage of 6 irnages and stored as tagged image file format (TIFF), compressed at 4 levels (25:1, 50:1, 75:1, and 100:1) using a wavelet algorithm, and displayed to the observers on a computer monitor. Their observations regarding condylar faceting, sclerosis, osteophyte formation, erosion, and abnormal shape were analyzed using ROC. Kappa values were determined for relative condylar size and condylar position within the glenoid fossa. Indices were compared using ANOVA at a significance level of P < .05. Although significant and substantial observer variability was demonstrated, there were no statistically significant differences between image modalities, except for condylar position, in which TIFF and wavelet (at all compression ratios) performed better than the original image. For faceting, wavelet 100:1 performed better than radiographic film images. Little actual image fUe reduction was achieved at compression ratios above 25:1.

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Spatial Resolution Requirements in Digital Radiography of Scaphoid Fractures

Abstract: The pixel size of 170 microns is adequate for the detection of subtle fractures, even after wavelet compression by a ratio of 10:1.

Cited by 11 publications

References 23 publications

A lesion detectability simulation method for digital x‐ray imaging

A lesion detectability simulation method for digital x‐ray imaging

Modified carpal box technique in the diagnosis of suspected scaphoid fractures

Diagnostic accuracy of film-based, TIFF, and wavelet compressed digital temporomandibular joint images

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