ABSTRACT
Clinical researchers are evaluating the utility of obtaining sequential images of pigmented lesions taken over time for purposes of comparison with the aim of detecting subtle changes suggestive of melanoma. Therefore, the image acquisition process is critical and will need to be strictly standardized before any firm conclusions can be drawn from analysis of sequential images. The influence of patient positioning on the accuracy of sequential image analysis has not been considered in most studies evaluating sequential images. In this experimental study, the influence of patient positioning on the size and shape of an inked circle placed on the skin was determined and measured. Inked circular marks (15 mm in diameter, area 176.71 mm2) were placed on the skin of the lumbar and suprascapular areas of 60 consecutive patients. The diameter and area of the 'circle' was measured with the patient in the prone position with head centred, prone position with head turned to the right, prone position with head turned left, and in the seated position. Statistical analysis was performed with Student's t-tests (paired data). We observed statistically significant differences in the shape, mean maximal diameter and area of the inked circular marks on both the suprascapular area and in the lumbar area after changes of patient positioning (P<0.001). To conclude, the position of the patient must be fixed and standardized during acquisition of sequential images, at least for lesions 15 mm in diameter or larger. Furthermore, it is our opinion that the methods used to control for patient positioning should be reported in the methodology section of studies that report on comparison of sequential images. Only then can we accurately compare sequential images and avoid 'false positive lesion enlargement' being categorized as a true change.
Subject(s)
Diagnostic Imaging/standards , Melanoma/diagnosis , Skin Neoplasms/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Analysis of Variance , False Positive Reactions , Female , Humans , Male , Middle Aged , Phantoms, Imaging , Prone Position , Reference StandardsABSTRACT
BACKGROUND: The coexistence of granuloma annulare (GA) and autoimmune thyroiditis (AT) has been sporadically observed in female patients, but the significance of this rarely reported association remains uncertain. OBJECTIVE: To investigate for the first time the frequency and type of thyroid disease in adult women with localized granuloma annulare (LGA) compared with a matched control group. METHODS: Twenty-four adult women with histology-proven LGA and a control group of 100 age-matched female patients with other unrelated cutaneous diseases were screened for thyroid disease in a tertiary teaching hospital in northern Spain. Laboratory evaluation included routine hematologic and chemistry analysis, antinuclear antibody, rheumatoid factor, thyroid function test (sensitive thyroid-stimulating hormone [TSH]), thyroid autoantibody levels, and antibodies to thyroid peroxidase in all patients and controls. Thyroid hormones (free triiodothyroxine and free thyroxine) were measured when TSH value was abnormal. AT was defined as hypothyroidism (TSH value >5 mU/L) and in addition to elevated antithyroid antibodies or characteristic thyroid biopsy. The results were compared using Fisher's exact test. RESULTS: Statistical evaluation of the findings obtained in this study showed mainly that the frequency of AT was increased significantly in the group of adult women with LGA (3/24, 12%) compared with the matched control group (1/100) (Fisher's exact test: P =.022). CONCLUSION: Although little can be inferred from a single investigation, the results of this pilot study indicate an association between LGA and AT in adult female patients, supporting the theory that at least a subset of GA belongs to the spectrum of autoimmune diseases.
