665 research outputs found
SYSTEM FOR AUTOMATIC DETECTION OF CLUSTERED MICROCALCIFICATIONS IN DIGITAL MAMMOGRAMS
In this paper, we investigate the performance of a Computer Aided Diagnosis (CAD) system for the detection of clustered microcalcifications in mammograms. Our detection algorithm consists of the combination of two different methods. The first, based on difference-image techniques and gaussianity statistical tests, finds out the most obvious signals. The second, is able to discover more subtle microcalcifications by exploiting a multiresolution analysis by means of the wavelet transform. We can separately tune the two methods, so that each one of them is able to detect signals with similar features. By combining signals coming out from the two parts through a logical OR operation, we can discover microcalcifications with different characteristics. Our algorithm yields a sensitivity of 91.4% with 0.4 false positive cluster per image on the 40 images of the Nijmegen database
Xâray Tomography Unveils the Construction Technique of UnâMontuâs Egyptian Coffin (Early 26th Dynasty)
The Bologna Archaeological Museum, in cooperation with prestigious Italian universities, institutions, and independent scholars, recently began a vast investigation programme on a group of Egyptian coffins of Theban provenance dating to the first millennium BC, primarily the 25thâ26th Dynasty (c. 746â525 BC). Herein, we present the results of the multidisciplinary investigation car-ried out on one of these coffins before its restoration intervention: the anthropoid wooden coffin of UnâMontu (Inv. MCABo EG1960). The integration of radiocarbon dating, wood species identifica-tion, and CT imaging enabled a deep understanding of the coffinâs wooden structure. In particular, we discuss the results of the tomographic investigation performed in situ. The use of a transportable Xâray facility largely reduced the risks associated with the transfer of the large object (1.80 cm tall) out of the museum without compromising image quality. Thanks to the 3D tomographic imaging, the coffin revealed the secrets of its construction technique, from the rational use of wood to the employment of canvas (incamottatura), from the use of dowels to the assembly procedure
Transannular patching is a valid alternative for tetralogy of Fallot and complete atrioventricular septal defect repair
Objective: We report our experience with repair of tetralogy of Fallot associated with complete atrioventricular
septal defect, addressing in particular the need for a pulmonary valve in the right ventricular outflow tract.
Methods: Between 1992 and 2006, 33 children with tetralogy of Fallot and complete atrioventricular septal defect
were admitted; 26 had Downâs syndrome (79%). Thirty-two children had complete repair (18 primary, 14
staged); of the 15 who received initial palliation, 1 died before complete repair. Right ventricular outflow tract
obstruction was relieved by transannular patch in 14 cases (42%), infundibular patch with preservation of the
pulmonary valve in 7 (21%), and right ventricleâtoâpulmonary artery conduit in 11 (33%).
Results: There were no hospital deaths. Actuarial survival was 96% 3.9% at 5 years and 85.9 1.1% at 10
years. Multivariate analysis showed that type of relief of right ventricular outflow tract obstruction did not influence
survival (P Œ .16), nor did the choice to use a valved conduit (P Œ .82). Primary correction (P Œ .05) and
lower weight at repair (P Œ .05) were associated with higher probability of survival. Mean follow-up was 69.3
5.9 months (range 0.2â282 months). There were 2 late deaths. Overall freedom from reoperation was 69% at 5
years and 38%at 10 years. Right ventricular outflow tract reconstruction without use of a valved conduit allowed
a significantly higher freedom from reinterventions (P<.05).
Conclusions: Tetralogy of Fallot associated with complete atrioventricular septal defect can be corrected at low
risk with favorable intermediate survival. Use of right ventricleâtoâpulmonary artery conduit can be avoided in
two thirds of patients with no impact on survival, possibly improving overall freedom from reintervention
Transannular patching is a valid alternative for tetralogy of Fallot and complete atrioventricular septal defect repair
Objective: We report our experience with repair of tetralogy of Fallot associated with complete atrioventricular
septal defect, addressing in particular the need for a pulmonary valve in the right ventricular outflow tract.
Methods: Between 1992 and 2006, 33 children with tetralogy of Fallot and complete atrioventricular septal defect
were admitted; 26 had Downâs syndrome (79%). Thirty-two children had complete repair (18 primary, 14
staged); of the 15 who received initial palliation, 1 died before complete repair. Right ventricular outflow tract
obstruction was relieved by transannular patch in 14 cases (42%), infundibular patch with preservation of the
pulmonary valve in 7 (21%), and right ventricleâtoâpulmonary artery conduit in 11 (33%).
Results: There were no hospital deaths. Actuarial survival was 96% 3.9% at 5 years and 85.9 1.1% at 10
years. Multivariate analysis showed that type of relief of right ventricular outflow tract obstruction did not influence
survival (P Œ .16), nor did the choice to use a valved conduit (P Œ .82). Primary correction (P Œ .05) and
lower weight at repair (P Œ .05) were associated with higher probability of survival. Mean follow-up was 69.3
5.9 months (range 0.2â282 months). There were 2 late deaths. Overall freedom from reoperation was 69% at 5
years and 38%at 10 years. Right ventricular outflow tract reconstruction without use of a valved conduit allowed
a significantly higher freedom from reinterventions (P<.05).
Conclusions: Tetralogy of Fallot associated with complete atrioventricular septal defect can be corrected at low
risk with favorable intermediate survival. Use of right ventricleâtoâpulmonary artery conduit can be avoided in
two thirds of patients with no impact on survival, possibly improving overall freedom from reintervention
Pathogenesis of secondary hyperparathyroidism
Chronic renal failure is the primary cause of secondary hyperparathyroidism (SHPT). Patients with mineral metabolism disorders commonly present with low serum calcium levels, hyperphosphatemia, and calcitriol deficiency. In normal renal function subjects, parathyroid cells have a low turnover and rarely undergo mitoses. In uremic conditions, however, parathyroid glands become hyperplasic and leave quiescence. During the last ten years, new molecular mechanisms have been investigated to better understand the pathogenesis of SHPT: the emerging role of the Calcium Sensing Receptor (CaSR); the importance of the parathyroid expression of the Vitamin D receptor (VDR); the growing evidence on the central role of the Fibroblast Growth Factor 23 (FGF-23). In contrast, the discovery of a parathyroid phosphate sensor or receptor has yet to be made
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