Studies on the use of non-Rayleigh statistics for ultrasonic tissue characterization.

The research groups at Drexel University and Thomas Jefferson University had proposed the use of non-Rayleigh statistics for tissue characterization. Previous work based on the hypothesis that the envelope of the backscattered echosignal from abnormal regions of the tissue is more likely to be K-distributed than Rayleigh distributed, used the parameter of the K-distribution, M, to distinguish between regions containing benign or malignant masses and normal ones. In this work the B-scan breast images of 19 patients were studied using this approach. Previous studies have also been extended to exploit the existence of non-uniform phase characteristics of the echosignal from scatterers with some regular spacings, such as those in a periodic or quasi-periodic alignment. Computer simulations were carried out to show that the phase statistics deviate significantly from uniform in the range of (0, 2 pi) if the imaging region contained a number of periodically aligned (regular lattice) scatterers along with a collection of randomly distributed scatterers resulting in a quasi-periodic arrangement. This methodology was then applied to B-scan images of the breasts to distinguish between benign and malignant masses. If benign lesions show some sort of quasi-periodic or regular structures in the tissue, they will present non-uniform phase characteristics while more randomly structured malignant masses will have uniform phase characteristics. It is seen that the K-distribution may be used to identify the abnormal regions in the breast images and information on the phase may be used to further separate the abnormal regions into benign and malignant ones.

Immunophenotypic features of uterine stromal cells. CD34 expression in endocervical stroma.

CD34 is a myeloid progenitor cell antigen present in endothelial cells and some other mesenchymal cells, including perivascular and periadnexal dermal fibroblasts. It was evaluated immunohistochemically in uterine stromal tissue and in 4 aggressive angiomyxomas and 6 endometrial stromal sarcomas with potentially related and similar stromal tissues. The stromal cells in normal endocervix and endocervical polyps were strongly CD34 positive irrespective of the cycle phase, and negative for muscle actins. Ectocervical stroma was variably but generally less CD34 reactive. In the endometrium, the CD34 reactivity was limited to the stromal cells of the basal endometrium and was found only in 4 of 20 from proliferative endometria and 1 of 8 from secretory endometria. The uterine cervical and myometrial smooth muscle tissues showed CD34 positive cells only between the muscle bundles and around the vessels. In pelvic aggressive angiomyxomas and endometrial stromal sarcomas the tumour cells were CD34 negative and only the vascular endothelial cells were positive. Endothelial cell-specific antigen, CD31, was identified only in endothelial cells and was not present in the endocervical stroma. These results illustrate the particular immunohistochemical profile of endocervical stromal tissue, namely the strong CD34 expression. The CD34 reactivity of the endocervical tissues should be noted and not confused with neoplasms known to be strongly CD34 positive, such as angiosarcomas, Kaposi's sarcomas and some other spindle cell sarcomas.

Endothelial cell markers CD31, CD34, and BNH9 antibody to H- and Y-antigens--evaluation of their specificity and sensitivity in the diagnosis of vascular tumors and comparison with von Willebrand factor.

Sixty vascular tumors including 23 angiosarcomas, 300 nonvascular tumors, and selected normal tissues were immunohistochemically evaluated with antibodies to CD31, CD34, and von Willebrand factor (vWF), and monoclonal antibody BNH9, to test the sensitivity and specificity of these markers in the identification of endothelial cells and vascular tumors. Formaldehyde-fixed paraffin-embedded tissues and avidin biotin complex immunostaining were used. All markers labeled normal vascular and lymphatic endothelial cells approximately equally with the exception of CD34 which showed inconsistent expression within the lymphatics. In addition, antibody to CD31 reacted with platelets and megakaryocytes, CD34 with fibroblasts and aortic smooth muscle cells, and BNH9 with many epithelial cells including squamous and gastrointestinal epithelia. Antibody to vWF often showed significant stromal background staining which made the staining occasionally uninterpretable. Benign vascular tumors showed rather uniform staining with all antibodies. However, angiosarcomas were heterogeneous; CD31 was positive in 21/27, CD34 in 25/27 cases, BNH9 in 22/25, and vWF in 18/27 cases. Epithelioid hemangioendotheliomas showed consistent labeling for vWF, but were inconsistently labeled with antibodies to the other markers. Kaposi's sarcoma was positive for both CD31 and CD34. In addition, antibody to CD34 labeled the tumor cells in hemangiopericytoma, cerebellar hemangioblastoma, meningioma, most epithelioid sarcomas, dermatofibrosarcomas, and in a few other sarcomas. CD31, in turn, was not found in sarcomas other than angiosarcomas, but labeled weakly occasional carcinomas and mesotheliomas. Many adenocarcinomas and the glandular component of synovial sarcoma were BNH9 positive.(ABSTRACT TRUNCATED AT 250 WORDS)