This simple and reliable method has the potential as an effective modality to investigate the composition of noncalcified coronary artery plaques and thus help in their characterization. In this inversion method, (ρ(e), Z(eff)) of the scanned sample can be found by eliminating the effects of the CT machine and also by ensuring that the determination of the two unknowns (ρ(e), Ze(ff)) does not interfere with each other and the nature of the plaque can be identified in terms of a three component model.

Purpose Calcium sensing receptor (CaSR), on the surface of normal parathyroid cells, is essential for maintaining serum calcium levels. The normal pattern of CaSR immunostaining remains undefined and is presumptively circumferential. Given the physiological variation in serum calcium, we postulated that CaSR expression could not be uniformly circumferential. Also, cytoplasmic expression has not been evaluated either in normal or pathological tissues. We studied normal parathyroid tissues derived from forensic autopsies and those rimming parathyroid adenomas for membranous and cytoplasmic CaSR immunoexpression. Results were compared with primary hyperparathyroidism (PHPT) to look for any pathogenetic implications. Materials and methodsWe evaluated 34 normal parathyroid tissues from 11 autopsies, 30 normal rims, 45 parathyroid adenoma, 10 hyperplasia, and 7 carcinoma cases. Membranous expression was categorized complete/incomplete and weak/ moderate/strong; scored using Her2/Neu and Histo-scores; predominant pattern noted. Cytoplasmic expression was categorized negative/weak/moderate/strong; predominant intensity noted. Results Normal autopsy-derived parathyroid tissues were Her2/Neu 3 + , but incomplete membranous staining predominated in 85%. Their immune-scores were significantly more than the cases (p < < 0.05). The mean histo-score of normal rims was intermediate between the two (p < < 0.05). Cytoplasmic expression was strong in all autopsy-derived tissues, weak/negative in hyperplasia (100%), moderate in 16% adenomas, and 43% carcinomas. Conclusions Normal autopsy-derived parathyroid tissues showed strong but predominantly incomplete membranous expression. Surface CaSR expression decreased in PHPT and is probably an early event in parathyroid adenoma, seen even in normal rims. Whether there is a defect in CaSR trafficking from the cytoplasm to the cell surface in adenoma and carcinoma needs further evaluation.

Inversion of dual-energy computed tomography (DECT) data for obtaining the electron density and effective atomic number of substances has been a work in progress for the past forty years. It has been the practice to characterize the material in terms of Hounsfield Unit (HU) values obtained by two different energies. Since HU values are equipment-dependent quantities, it is necessary to develop a method that characterizes the substance in terms of certain physical quantities that are equipment independent. The process that we adopt is to find a calibration method by which all equipment-dependent quantities are eliminated and we directly deal with quantities that are representative of the sample, namely its electron density and effective atomic number. We collect the DECT data from 21 samples of non-calcified coronary artery plaques in human cadavers. With our standardized inversion method we have obtained the electron density and effective atomic number of these samples. With physical models of lipids and proteins it becomes possible to conclude that non-calcified plaque samples can have calcium dispersed in the lipid part of the plaque in trace amounts that cannot be observed by light based microscopy or by CT images alone. This characterization, may give a new insight in characterization of non-calcified coronary artery plaque and in medical diagnostics.