Tuberculine reaction measured by infrared thermography.

SETTING: The infection with Mycobacterium tuberculosis gives a delayed immune response, measured by the tuberculine skin test. We present a new technique for evaluation based on automatic detection and measurement of skin temperature due to infrared emission. DESIGN: 34 subjects (46.8±16.9 years) (12/22, M/F) with suspected tuberculosis disease were examined with an IR thermal camera, 48 h after tuberculin skin injection. RESULTS: In 20 subjects, IR analysis was positive for tuberculine test. Mean temperature of injection area was higher, around 1°C, for the positive group (36.2±1.1°C positive group; 35.1±1.6°C negative group, p<0.02 T test for unpaired groups). CONCLUSION: IR image analysis achieves similar estimation of tuberculin reaction as the visual evaluation, based on higher temperature due to increased heat radiation from the skin lesion.

Short term oxygen therapy effects in hypoxemic patients measured by drawing analysis.

BACKGROUND: Chronic hypoxemia has deleterious effects on psychomotor function that can affect daily life. There are no clear results regarding short term therapy with low concentrations of O2 in hypoxemic patients. We seek to demonstrate, by measuring the characteristics of drawing, these effects on psychomotor function of hypoxemic patients treated with O2. METHODS: Eight patients (7/1) M/F, age 69.5 (9.9) yr, mean (SD) with hypoxemia (Pa O2 62.2 (6.9) mmHg) performed two drawings of pictures. Tests were performed before and after 30 min breathing with O2. RESULTS: Stroke velocity increased after O2 for the house drawing (i.e. velocity 27.6 (5.5) mm/s basal, 30.9 (7.1) mm/s with O2, mean (SD), p<0.025, Wilcoxon test). The drawing time 'down' or fraction time the pen is touching the paper during the drawing phase decreased (i.e. time down 20.7 (6.6) s basal, 17.4 (6.3) s with O2, p<0.017, Wilcoxon test). CONCLUSIONS: This study shows that in patients with chronic hypoxemia, a short period of oxygen therapy produces changes in psychomotor function that can be measured by means of drawing analysis.

Fractal dimension analysis of malignant and benign endobronchial ultrasound nodes.

BACKGROUND: Endobronchial ultrasonography (EBUS) has been applied as a routine procedure for the diagnostic of hiliar and mediastinal nodes. The authors assessed the relationship between the echographic appearance of mediastinal nodes, based on endobronchial ultrasound images, and the likelihood of malignancy. METHODS: The images of twelve malignant and eleven benign nodes were evaluated. A previous processing method was applied to improve the quality of the images and to enhance the details. Texture and morphology parameters analyzed were: the image texture of the echographies and a fractal dimension that expressed the relationship between area and perimeter of the structures that appear in the image, and characterizes the convoluted inner structure of the hiliar and mediastinal nodes. RESULTS: Processed images showed that relationship between log perimeter and log area of hilar nodes was lineal (i.e. perimeter vs. area follow a power law). Fractal dimension was lower in the malignant nodes compared with non-malignant nodes (1.47(0.09), 1.53(0.10) mean(SD), Mann-Whitney U test p < 0.05)). CONCLUSION: Fractal dimension of ultrasonographic images of mediastinal nodes obtained through endobronchial ultrasound differ in malignant nodes from non-malignant. This parameter could differentiate malignat and non-malignat mediastinic and hiliar nodes.