The phase behavior and rheology of binary blends of polystyrene (PS) and poly(α-methylstyrene) (PαMS), exhibiting upper critical solution temperature (UCST), and binary blends of PS and poly(vinyl methyl ether) (PVME), exhibiting lower critical solution temperature (LCST), were investigated. For the study, (i) PS-40/PαMS-18, (ii) PS-38/PαMS-39, (iii) PS-40/PαMS-48, and (iv) PS-110/PVME-95 blend systems were prepared by solution casting. The results of differential scanning calorimetry suggest that each blend system investigated is miscible over the entire blend composition as evidenced by the single composition-dependent glass transition temperature. However, from oscillatory shear rheometry we observed evidence suggesting that microheterogeneity is present in the miscible region, as determined by cloud point measurements, at temperatures as far away as approximately 70 °C above the UCST of the PS/PαMS blend system and at temperatures as far away as only approximately 7 °C below the LCST of the PS/PVME blend system. Such observation leads us to conclude that the extent of dynamical composition fluctuations near the critical point depends on the chemical structures of a polymer pair. The observed difference in the extent of dynamical composition fluctuations between PS/PαMS and PS/PVME blend systems is interpreted by the difference in the temperature coefficient of the interaction parameter between the PS/PαMS and PS/PVME blend systems.

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No method has yet been approved for detecting lymphedema fibrosis before its progression. This study assessed the feasibility of computed tomography-based estimation of fibrosis. This observational, cross-sectional study included patients with lymphedema affecting one limb. Three types (maximum, mean, minimum) of computed tomography reticulation indexes were digitally calculated from trans-axial images using absorptive values, and the computed tomography reticulation indexes compared with clinical scales and measurements. Of 326 patients evaluated by at least one of lymphoscintigraphy, bio-electrical impedance, and computed tomography, 24 were evaluated by all three. The mean number of computed tomography scans in these patients was 109. Sixteen patients had breast cancer, seven had gynecologic cancers, and one had primary lymphedema. Mean computed tomography reticulation index (r = 0.52, p < 0.01) and maximal computed tomography reticulation index (r = 0.45, p < 0.05) were significantly associated with time from initial limb swelling to computed tomography. Mean computed tomography reticulation index (r = 0.86, p < 0.01), minimal computed tomography reticulation index (r = 0.79, p < 0.01), and maximal computed tomography reticulation index (r = 0.68, p < 0.01) were significantly associated with International Society of Lymphedema substage. Minimal computed tomography reticulation index correlated with 1-kHz-based bio-electrical impedance ratio (r = -0.46, p < 0.05) and with standardized proximal limb circumference difference ratio (r = 0.45, p < 0.05) of both limbs. Maximal computed tomography reticulation index had a sensitivity of 0.78, specificity of 0.60, and areas under the curve of 0.66 in detecting lymphoscintigraphic stage IV. The algorithm utilizing three-dimensional computed tomography images of epifascial fibrosis may be used as a marker for lymphedema duration, limb swelling, International Society of Lymphedema substage, and interstitial lymphatic fluids of lymphedema. The current approach shows promise in providing an additional method to assist in characterizing and monitoring lymphedema patients.

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