A computer-based method for precise detection and calculation of affected skin areas.

BACKGROUND: The aim of this study was to describe and validate a method to obtain reproducible and comparable results concerning extension of a specific skin area, unaffected by individual differences in body surface area. METHODS: A phantom simulating the human torso was equipped with three irregular areas representing the increasing extension of an affected skin area over time. A large sheet of flexible calques paper was placed at the phantom, and five clinicians copied the three irregular shapes two times, resulting in 60 copies. Subsequently, a digital photograph was taken of the calques papers with a clinical ruler placed at the margin. The images were postprocessed and measured in the program 'ImageJ' by two observers. An exact area measurement of the three irregular shapes was performed for comparison. RESULTS: We found an interobserver variation of 0·36% when comparing the measurements of all three areas. Comparing observer measurements with the exact areas size, we found an underestimate of 2·52%. We observed a tendency that the discrepancy in measurement increases when the measured area decreases. CONCLUSION: We find this method accurate, reproducible and easy to use. The presented method can be of help when documenting psoriasis and other dermatologic conditions as well as when exploring the effects of new types and variations of ultrasound-guided peripheral nerve blocks - especially in study volunteers.

External pneumatic compression device prevents fainting in standing weight-bearing MRI: a cohort study.

OBJECTIVE: To investigate if a peristaltic external pneumatic compression device attached to the legs, while scanning, can reduce a substantial risk of fainting in standing weight-bearing magnetic resonance imaging (MRI). MATERIALS AND METHODS: This study comprised all patients with low back pain referred to standing MRI of the lumbar spine, using a 0.25-T open G-Scanner, from June 2011 to April 2012. The standing MRI protocol included a sagittal TSE T2w and an axial GRE T2w sequence giving a total scan time of 17 min. The first patients were scanned standing without a device (control group), and then from January to April 2012 the patients were scanned in the standing position using an external pneumatic compression device, attached to the legs (experimental group). RESULTS: One hundred and forty-nine patients (mean age 42.5, standard deviation 12.5, and range 20-77 years) were included and scanned standing. No significant difference in age (p = 0.51) or gender (p = 0.47) was observed between the control group (n = 86) and the experimental group (n = 63). Sixteen patients (19 %) fainted in the control group during the standing MRI scan, compared to one patient (2 %) in the experimental group where the pneumatic compression device was applied. The difference between groups was highly significant (p = 0.001; Fisher's exact test), with an OR = 0.071 (exact 95 % CI: 0.002 to 0.486) for the pneumatic compression device. CONCLUSIONS: A substantial risk of fainting during standing MRI was almost eliminated by using an external peristaltic pneumatic compression device.

Correlation between computer-aided dynamic gadolinium-enhanced MRI assessment of inflammation and semi-quantitative synovitis and bone marrow oedema scores of the wrist in patients with rheumatoid arthritis--a cohort study.

OBJECTIVE: To test the correlation between assessment of inflammation using dynamic contrast-enhanced MRI (DCE-MRI) analysed by a novel computer-aided approach and semi-quantitative scores of synovitis and bone marrow oedema (BME) using the OMERACT-RA MRI Scoring (RAMRIS) system, in the wrist of patients with RA. METHODS: Fifty-four RA patients had conventional and DCE-MRI of a symptomatic wrist using a low-field 0.2T extremity scanner. RAMRIS synovitis and BME of the wrist joint were done. DCE-MRI data were analysed in three ways: (i) in all images (fully automated approach), (ii) within a large extended region of interest (ROI) placed around the wrist joint (semi-automated approach) and (iii) within a small ROI placed in the area with most visual enhancement (semi-automated approach). Time spent on each procedure was noted. Spearman's rank correlation test was applied to assess the correlation between RAMRIS and the computer-generated dynamic parameters. RESULTS: RAMRIS synovitis (range 2-9), BME (range 0-39) and the dynamic parameters reflecting the number of enhancing voxels were significantly correlated, especially when an extended ROI around the wrist was used (ρ = 0.74; P < 0.01 for synovitis and ρ = 0.82; P < 0.01 for BME). The observer spent on average 20 min (range 12-25 min) to perform RAMRIS, including acquisition of the results in the database, and 8 min (range 7-10 min) to perform all above-mentioned computer-aided analyses. CONCLUSION: Computer-aided analysis of DCE-MRI data correlated with RAMRIS synovitis and BME and was twice as fast to perform. This technique may be useful for quick semi-automated assessment of joint inflammation, but needs further validation.