Tissue-mimicking oil-in-gelatin dispersions for use in heterogeneous elastography phantoms.

A ten-month study is presented of materials for use in heterogeneous elastography phantoms. The materials consist of gelatin with or without a suspension of microscopic safflower oil droplets. The highest volume percent of oil in the materials is 50%. Thimerosal acts as a preservative. The greater the safflower oil concentration, the lower the Young's modulus. Elastographic data for heterogeneous phantoms, in which the only variable is safflower oil concentration, demonstrate stability of inclusion geometry and elastic strain contrast. Young's modulus ratios (elastic contrasts) producible in a heterogeneous phantom are as high as 2.7. The phantoms are particularly useful for ultrasound elastography. They can also be employed in MR elastography, although the highest achievable ratio of longitudinal to transverse relaxation times is considerably less than is the case for soft tissues.

Immediate and delayed effects of treatment at the Dead Sea in patients with psoriatic arthritis.

The purpose of this study was to evaluate the immediate and delayed effects of balneotherapy at the Dead Sea on patients with psoriatic arthritis (PsA). A total of 42 patients with PsA were treated at the Dead Sea for 4 weeks. Patients were randomly allocated into two groups: group 1 (23 patients) and group 2 (19 patients). Both groups received daily exposure to sun ultraviolet rays and regular bathing at the Dead Sea. Group 1 was also treated with mud packs and sulfur baths. Patients were assessed by a dermatologist and a rheumatologist 3 days before arrival, at the end of treatment, and at weeks 8, 16, and 28 from the start of treatment. The clinical indices assessed were morning stiffness, right and left hand grip, number of tender joints, number of swollen joints, Schober test, distance from finger to floor when bending forward, patient's self-assessment of disease severity, inflammatory neck and back pain and psoriasis area and severity index (PASI) score. Comparison between groups disclosed a similar statistically significant improvement for variables such as PASI, morning stiffness, patient self-assessment, right and left grip, Schober test and distance from finger to floor when bending forward. For variables such as tender and swollen joints, and inflammatory neck and back pain, improvement over time was statistically significant in group 1. Addition of mud packs and sulfur baths to sun ultraviolet exposure and Dead Sea baths seems to prolong beneficial effects and improves inflammatory back pain.

Elastographic characterization of HIFU-induced lesions in canine livers.

The elastographic visualization and evaluation of high-intensity focused ultrasound (HIFU)-induced lesions were investigated. The lesions were induced in vitro in freshly excised canine livers. The use of different treatment intensity levels and exposure times resulted in lesions of different sizes. Each lesion was clearly depicted by the corresponding elastogram as being an area harder than the background. The strain contrast of the lesion/background was found to be dependent on the level of energy deposition. A lesion/background strain contrast between -2.5 dB and -3.5 dB was found to completely define the entire zone of tissue damage. The area of tissue damage was automatically estimated from the elastograms by evaluating the number of pixels enclosed inside the isointensity contour lines corresponding to a strain contrast of -2.5, -3 and -3.5 dB. The area of the lesion was measured from a tissue photograph obtained at approximately the same plane where elastographic data were collected. The estimated lesion areas ranged between approximately 10 mm2 and 110 mm2. A high correlation between the damaged areas as depicted by the elastograms and the corresponding areas as measured from the gross pathology photographs was found (r2 = 0.93, p value < 0.0004, n = 16). This statistically significant high correlation demonstrates that elastography has the potential to become a reliable and accurate modality for HIFU therapy monitoring.