Different Types Of Nodules Research Articles

Volumetric measurement of pulmonary nodules at low-dose chest CT: effect of reconstruction setting on measurement variability

ObjectiveTo assess volumetric measurement variability in pulmonary nodules detected at low-dose chest CT with three reconstruction settings.MethodsThe volume of 200 solid pulmonary nodules was measured three times using commercially available semi-automated software of low-dose chest CT data-sets reconstructed with 1 mm section thickness and a soft kernel (A), 2 mm and a soft kernel (B), and 2 mm and a sharp kernel (C), respectively. Repeatability coefficients of the three measurements within each setting were calculated by the Bland and Altman method. A three-level model was applied to test the impact of reconstruction setting on the measured volume.ResultsThe repeatability coefficients were 8.9, 22.5 and 37.5% for settings A, B and C. Three-level analysis showed that settings A and C yielded a 1.29 times higher estimate of nodule volume compared with setting B (P = 0.03). The significant interaction among setting, nodule location and morphology demonstrated that the effect of the reconstruction setting was different for different types of nodules. Low-dose CT reconstructed with 1 mm section thickness and a soft kernel provided the most repeatable volume measurement.ConclusionA wide, nodule-type-dependent range of agreement between volume measurements with different reconstruction settings suggests strict consistency is required for serial CT studies.

A novel multithreshold method for nodule detection in lung CT

Multislice computed tomography (MSCT) is a valuable tool for lung cancer detection, thanks to its ability to identify noncalcified nodules of small size (from about 3 mm). Due to the large number of images generated by MSCT, there is much interest in developing computer-aided detection (CAD) systems that could assist radiologists in the lung nodule detection task. A complete multistage CAD system, including lung boundary segmentation, regions of interest (ROIs) selection, feature extraction, and false positive reduction is presented. The selection of ROIs is based on a multithreshold surface-triangulation approach. Surface triangulation is performed at different threshold values, varying from a minimum to a maximum value in a wide range. At a given threshold value, a ROI is defined as the volume inside a connected component of the triangulated isosurface. The evolution of a ROI as a function of the threshold can be represented by a treelike structure. A multithreshold ROI is defined as a path on this tree, which starts from a terminal ROI and ends on the root ROI. For each ROI, the volume, surface area, roundness, density, and moments of inertia are computed as functions of the threshold and used as input to a classification system based on artificial neural networks. The method is suitable to detect different types of nodules, including juxta-pleural nodules and nodules connected to blood vessels. A training set of 109 low-dose MSCT scans made available by the Pisa center of the Italung-CT trial and annotated by expert radiologists was used for the algorithm design and optimization. The system performance was tested on an independent set of 23 low-dose MSCT scans coming from the Pisa Italung-CT center and on 83 scans made available by the Lung Image Database Consortium (LIDC) annotated by four expert radiologists. On the Italung-CT test set, for nodules having a diameter greater than or equal to 3 mm, the system achieved 84% and 71% sensitivity at false positive/scan rates of 10 and 4, respectively. For nodules having a diameter greater than or equal to 4 mm, the sensitivities were 97% and 80% at false positive/scan rates of 10 and 4, respectively. On the LIDC data set, the system achieved a 79% sensitivity at a false positive/scan rate of 4 in the detection of nodules with a diameter greater than or equal to 3 mm that have been annotated by all four radiologists.

Sprent, J.I. Nodulation in legumes

This book is a welcome addition to the existing, extensive, but now outdated literature on legumes and their interactions with nitrogen‐fixing root‐nodulating bacteria. Over the past 30 years, there has been extensive reclassification of both the legumes and of the rhizobia that nodulate them, and the terminology can be very confusing to anyone new to the field. However, clear guidance is needed because the subject is of great interest not only to microbiologists and plant scientists, but also to ecologists, agronomists and many others who do not keep up with the latest scientific literature. The ability of leguminous plants to enrich the soil has been known for millennia. The role of rhizobia in forming nitrogen‐fixing root nodules has been known for over a century, and details of the molecular interactions between the plant and bacterial partners in this symbiosis have been revealed in the last two decades. The title, Nodulation in legumes, accurately describes the contents of the book, as it covers all relevant aspects. These range from a description of the legumes and different groups of rhizobia, to details of the mechanisms by which different types of nodules are formed, including recent findings on molecular signalling and on plant and bacterial phylogeny. Although the book is not very long, it is clear and concise and provides enough detail to give a full picture of current knowledge in the areas it covers. There are plenty of references to recent research papers for readers who need more depth. There is also a comprehensive list of the various taxonomic groups that comprise the legumes, and information about their nodulation status; this is useful as such information can be very difficult to find in the older literature that uses outdated classification. The book is A4 size and the pages are well set out, with good illustrations and some colour plates of plants and nodules that are especially informative. It is easy to read and it will be invaluable for undergraduate and postgraduate students who are studying symbiotic nitrogen fixation, and for anyone who needs a good, general, contemporary text to introduce the topic. However, I also recommend it to specialists in the field of legume/rhizobial symbiosis as it provides a very useful overview of the changes in terminology over recent years, and thus should help to prevent confusion. In summary, it is a timely book that should appeal to a diverse readership.

Stromal nodules in benign prostatic hyperplasia.

Stromal nodules from benign prostatic hyperplasia (BPH; n = 375 from autopsy, n = 100 from biopsy specimens) were investigated with regard to cytoskeletal components, topography, vascularization, leukocytic infiltrates, and proliferative activity. The nature of stromal nodules was studied by histopathology and immunohistochemistry, using antibodies against alpha-actin, desmin, myosin, vimentin, BMA-120, factor VIII, CD3, CD4, CD20, CD34, CD45RO, CD68, PCNA, and MiB1. The findings lead to an extended classification of stromal nodules in BPH: immature mesenchymal (IM; 8.8%), fibroblastic (FB; 65.2), fibromuscular (FM; 21.6), and smooth muscular (SM; 4.4%). The different types occurred in all age decades in a similar distribution (FB > FM > IM > SM). Topographical studies (modified zonal subdivision of McNeal) revealed stromal nodules predominantly in the transitional zone (n = 286), less in the central zone (n = 78), occasionally in the peripheral zone (n = 11), and predominantly in the periurethral (n = 287) and less in the intermediate (n = 84) and subcapsular (n = 4) regions. The different types of nodules presented a distinct vascular pattern. FB, FM, and SM nodules showed significantly increased diffuse infiltrates of T lymphocytes-mainly T helper cells (mean 73%)-and an increase of B lymphocytes. Proliferative activity in the nodules was not observed. Stromal nodules were not observed in normal nonhyperplastic prostates; they only occurred in combination with hyperplastic nodular glandular proliferates. The findings are suggestive of a maturational sequence of stromal nodules in BPH and of a possible significance of immunocompetent cells in the development of stromal nodules and further suggest that both stroma and epithelium of the prostate respond with nodular hyperplasia to the stimulus, which causes BPH.

CONCENTRATION, SOURCE OF MANGANESE AND IRON IN FERROMANGANESE NODULES AND THE RELATIONSHIP BETWEEN NODULES AND SEDIMENTARY ENVIRONMENTS IN NORTH PACIFIC REGION

The concentration, source of manganese and iron in ferromanganese nodules and therelation between nodules and sedimentary environments are discussed in detail by asynthetical study on chemical information of ferromanganese nodules and correspondingsediment, pore water and geological, biological (bacteria) information in 26 stations fromthe North Pacific region (7- 13°N, 178- 165°W). The result shows that (i) the concen-tration and distribution characteristics of magnese and iron in ferromanganese nod-ules differ in different types of nodules, however, the concentration decreases with theincrease in grain sizes of nodules; (ii) the source of iron in different types of nodulesis basically the same, i. e. the slow sedimentation of overlying water; (iii) manganesein nodules comes mainly from the diffusion of Mn~(2+) in the pore water, and Mn~(2+) fromthe reduction of Mn~(4+) in sediments by the medium of bacteria. As the distribution of bac-teria is believed to be strongly affected by the sedimentary environment, differenttypes of nodules are formed in the different environments.

The feeding system of Vesuvius between 1754 and 1944

The occurrence of short-term variations of Sr isotopic ratios in the Vesuvian historical lavas, and the occurrence of different types of nodules, which formed in different P-T conditions, permit the identification of two different deep magmatic reservoirs. The cumulative effusion rate of Vesuvius between 1694 and 1944 allows a calculation of the magma production rate in the same period. Based on these data, a model of the Vesuvian feeding system is presented. Between 1754 and 1944 mixing of magmas probably occurred in two deep-seated magma reservoirs. We calculated the volume of such reservoirs (∼ 0.1 km 3). The increased effusion rate of Vesuvius after 1858 is nicely explained by the simultaneous activity of both reservoirs. Geometrical constraints on the Vesuvian conduit are also discussed.

Characteristics and genesis of nodules and concretions occurring in soils of the R. Chinit area, Kompong Thom Province, Cambodia

Abstract Morphological, chemical and mineralogical studies were made on different types of nodules and concretions occurring in Gleysols, Ferralsols and Vertisols of the R. Chinit area, Kompong Thorn Province, Cambodia. The examinations indicated that nodules have developed through impregnation of soil matrix with iron and/or manganese oxides, whilceoncretions have formed through periodical precipitation of iron oxide around ferruginous or manganiferous nuclei to the exclusion of surrounding soil materials. Alternation of wet and dry seasons is believed to play an important part in the localization of iron and manganese into mottles and their subsequent hardening. The proportion of anhydrous iron oxides (hematite, maghemite) to hydrated iron oxide (goethite) appears to be closely related to the degree of desiccation of soils in dry seasons. Decomposition of kaolinite in the nodules and concretions was suggested by their lower kaolinite, and higher amorphous silica and alumina contents as compared to the s...