141 research outputs found
Colorectal Carcinoma: Local Tumor Staging and Assessment of Lymph Node Metastasis by High-Resolution MR Imaging in Surgical Specimens
Purpose. To assess the accuracy of high-resolution MR imaging as a means of evaluating mural invasion and lymph node metastasis by colorectal carcinoma in surgical specimens. Materials and Methods. High-resolution T1-weighted and T2-weighted MR images were obtained in 92 surgical specimens containing 96 colorectal carcinomas. Results. T2-weighted MR images clearly depicted the normal colorectal wall as consisting of seven layers. In 90 (94%) of the 96 carcinomas the depth of mural invasion depicted by MR imaging correlated well with the histopathologic stage. Nodal signal intensity on T2-weighted images (93%) and nodal border contour (93%) were more accurate than nodal size (89%) as indicators of lymph node metastasis, and MR imaging provided the highest accuracy (94%–96%) when they were combined. Conclusion. High-resolution MR imaging is a very accurate method for evaluating both mural invasion and lymph node metastasis by colorectal carcinoma in surgical specimens
The brightest UV-selected galaxies in protoclusters at : Ancestors of Brightest Cluster Galaxies?
We present the results of a survey of the brightest UV-selected galaxies in
protoclusters. These proto-brightest cluster galaxy (proto-BCG) candidates are
drawn from 179 overdense regions of -dropout galaxies at from the
Hyper Suprime-Cam Subaru Strategic Program identified previously as good
protocluster candidates. This study is the first to extend the systematic study
of the progenitors of BCGs from to . We carefully remove
possible contaminants from foreground galaxies and, for each structure, we
select the brightest galaxy that is at least 1 mag brighter than the fifth
brightest galaxy. We select 63 proto-BCG candidates and compare their
properties with those of galaxies in the field and those of other galaxies in
overdense structures. The proto-BCG candidates and their surrounding galaxies
have different rest-UV color distributions to field galaxies and
other galaxies in protoclusters that do not host proto-BCGs. In addition,
galaxies surrounding proto-BCGs are brighter than those in protoclusters
without proto-BCGs. The image stacking analysis reveals that the average
effective radius of proto-BCGs is larger than that of field
galaxies. The color differences suggest that proto-BCGs and their
surrounding galaxies are dustier than other galaxies at . These results
suggest that specific environmental effects or assembly biasses have already
emerged in some protoclusters as early as , and we suggest that
proto-BCGs have different star formation histories than other galaxies in the
same epoch.Comment: 18 pages, 11 figures, Accepted for publication in Ap
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