Internet hand x-rays: A comparison of joint space narrowing and erosion scores (Sharp/Genant) of plain versus digitized x-rays in rheumatoid arthritis patients

Computer-based measurements of joint space analysis using metacarpal morphometry in hand radiograph for evaluation of rheumatoid arthritis

AIM AND OBJECTIVES

The aim and objectives are as follows: (i) to perform an automated segmentation of the hand from radiographs using a dual tree complex wavelet-based watershed algorithm; ii) to compare the measured statistical features of the joint space of the hand using gray level co-occurrence matrix (GLCM) method with standard diagnostic parameters of rheumatoid arthritis (RA).

METHODS

Fifty-three patients with RA and 17 age- and sex-matched healthy controls were included in the study. The erythrocyte sedimentation rate (ESR), C-reactive protein, rheumatoid factor, health assessment questionnaire score (HAQ), disease activity score (DAS) and hand radiographs of all the subjects were obtained. Joint space width and cortical thickness were measured in metacarpophalangeal joints (MCP) and metacarpal bone semi-automatically using MIMICS software. Dual tree complex wavelet transform-based watershed algorithm was applied for automated segmentation, and feature extraction was performed using the GLCM method in hand radiographs of the total population.

RESULTS

In the RA group (n = 53), the joint space width measured in the MCP1, MCP3, MCP5 of the hand were reduced significantly (P < 0.01) by 16.4%, 15.6%, and 17.5%, respectively compared to the normal group (n = 17). The measured combined cortical thickness at the second, third and fourth metacarpal bones of the hand were reduced significantly (P < 0.01) by 9.5%, 12% and 8%, respectively in the RA group compared to the normal group.

CONCLUSION

The dual tree complex wavelet transform-based watershed algorithm provided effective segmentation in the digitized hand radiographs. The standard diagnostic parameters for RA were highly correlated with measured statistical features at MCP3 hand joint in the total population studied.

Method comparison of automated matching software-assisted cone-beam CT and stereoscopic kilovoltage x-ray positional verification image-guided radiation therapy for head and neck cancer: a prospective analysis

We sought to characterize interchangeability and agreement between cone-beam computed tomography (CBCT) and digital stereoscopic kV x-ray (KVX) acquisition, two methods of isocenter positional verification currently used for IGRT of head and neck cancers (HNC). A cohort of 33 patients were near-simultaneously imaged by in-room KVX and CBCT. KVX and CBCT shifts were suggested using manufacturer software for the lateral (X), vertical (Y) and longitudinal (Z) dimensions. Intra-method repeatability, systematic and random error components were calculated for each imaging modality, as were recipe-based PTV expansion margins. Inter-method agreement in each axis was compared using limits of agreement (LOA) methodology, concordance analysis and orthogonal regression. 100 daily positional assessments were performed before daily therapy in 33 patients with head and neck cancer. Systematic error was greater for CBCT in all axes, with larger random error components in the Y- and Z-axis. Repeatability ranged from 9 to 14 mm for all axes, with CBCT showing greater repeatability in 2/3 axes. LOA showed paired shifts to agree 95% of the time within +/-11.3 mm in the X-axis, +/-9.4 mm in the Y-axis and +/-5.5 mm in the Z-axis. Concordance ranged from 'mediocre' to 'satisfactory'. Proportional bias was noted between paired X- and Z-axis measures, with a constant bias component in the Z-axis. Our data suggest non-negligible differences in software-derived CBCT and KVX image-guided directional shifts using formal method comparison statistics.

Digitized hand-wrist radiographs: Comparison of subjective and software-derived image quality at various compression ratios

INTRODUCTION

The objectives of this study were to compare the effect of JPEG 2000 compression of hand-wrist radiographs on observer image quality qualitative assessment and to compare with a software-derived quantitative image quality index.

METHODS

Fifteen hand-wrist radiographs were digitized and saved as TIFF and JPEG 2000 images at 4 levels of compression (20:1, 40:1, 60:1, and 80:1). The images, including rereads, were viewed by 13 orthodontic residents who determined the image quality rating on a scale of 1 to 5. A quantitative analysis was also performed by using a readily available software based on the human visual system (Image Quality Measure Computer Program, version 6.2, Mitre, Bedford, Mass). ANOVA was used to determine the optimal compression level (P < or =.05).

RESULTS

When we compared subjective indexes, JPEG compression greater than 60:1 significantly reduced image quality. When we used quantitative indexes, the JPEG 2000 images had lower quality at all compression ratios compared with the original TIFF images. There was excellent correlation (R2 >0.92) between qualitative and quantitative indexes.

CONCLUSIONS

Image Quality Measure indexes are more sensitive than subjective image quality assessments in quantifying image degradation with compression. There is potential for this software-based quantitative method in determining the optimal compression ratio for any image without the use of subjective raters.

Method comparison of ultrasound and kilovoltage x-ray fiducial marker imaging for prostate radiotherapy targeting

Several measurement techniques have been developed to address the capability for target volume reduction via target localization in image-guided radiotherapy; among these have been ultrasound (US) and fiducial marker (FM) software-assisted localization. In order to assess interchangeability between methods, US and FM localization were compared using established techniques for determination of agreement between measurement methods when a 'gold-standard' comparator does not exist, after performing both techniques daily on a sequential series of patients. At least 3 days prior to CT simulation, four gold seeds were placed within the prostate. FM software-assisted localization utilized the ExacTrac X-Ray 6D (BrainLab AG, Germany) kVp x-ray image acquisition system to determine prostate position; US prostate targeting was performed on each patient using the SonArray (Varian, Palo Alto, CA). Patients were aligned daily using laser alignment of skin marks. Directional shifts were then calculated by each respective system in the X, Y and Z dimensions before each daily treatment fraction, previous to any treatment or couch adjustment, as well as a composite vector of displacement. Directional shift agreement in each axis was compared using Altman-Bland limits of agreement, Lin's concordance coefficient with Partik's grading schema, and Deming orthogonal bias-weighted correlation methodology. 1,019 software-assisted shifts were suggested by US and FM in 39 patients. The 95% limits of agreement in X, Y and Z axes were +/-9.4 mm, +/-11.3 mm and +/-13.4, respectively. Three-dimensionally, measurements agreed within 13.4 mm in 95% of all paired measures. In all axes, concordance was graded as 'poor' or 'unacceptable'. Deming regression detected proportional bias in both directional axes and three-dimensional vectors. Our data suggest substantial differences between US and FM image-guided measures and subsequent suggested directional shifts. Analysis reveals that the vast majority of all individual US and FM directional measures may be expected to agree with each other within a range of 1-1.5 cm. Since neither system represents a gold standard, clinical judgment must dictate whether such a difference is of import. As IMRT protocols seek dose escalation and PTV reduction predicated on US- and FM-guided imaging, future studies are needed to address these potential clinically relevant issues regarding the interchangeability and accuracy of novel positional verification techniques. Comparison series with multiple image-guidance systems are needed to refine comparisons between targeting methods. However, we do not advocate interchangeability of US and FM localization methods.

Madelung's deformity: quantitative assessment of x-ray deformity

PURPOSE

To evaluate 5 defined measurement techniques that are applicable to x-rays of Madelung's deformity: ulnar tilt, lunate subsidence, lunate fossa angle, palmar tilt, and palmar carpal displacement. The measurements rely on the longitudinal axis of the ulna and the carpal bones to determine drawing lines and avoid the distorted distal radius and its deformed lunate fossa. The reliability and reproducibility of the measurements is determined.

METHODS

Forty-eight sets of posteroanterior and lateral x-ray views of the wrist of subjects with the clinical diagnosis of Madelung's deformity were measured by 4 raters. Each rater made the 5 defined measurements on each pair of x-rays. Pairs of raters were compared for reliability using the Pearson correlation coefficient and Lin's concordance correlation coefficient. Two raters repeated the 4 reliable measurements a minimum of 6 months after the first measurements. Each rater's results were compared for reproducibility using Lin's concordance correlation coefficient.

RESULTS

Ulnar tilt and lunate subsidence have excellent reliability and reproducibility. Palmar carpal displacement has acceptable reliability and reproducibility. Lunate fossa angle has borderline reliability but excellent reproducibility. Palmar tilt has poor reliability.

CONCLUSIONS

Ulnar tilt, lunate subsidence, and palmar carpal displacement, as defined, are considered reliable and reproducible measurements for quantifying the severity of Madelung's deformity on x-rays. Lunate fossa angle is not sufficiently reliable for comparing preoperative and postoperative wrists but may prove useful in establishing an early diagnosis. Palmar tilt is not measured reliably on a lateral x-ray because of the superimposition of multiple structures on a lateral x-ray and the absence of the volar part of the lunate fossa in patients with severe Madelung's deformity. Advanced imaging techniques are needed to delineate the deformity of the distal radius in a lateral projection.