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Biomedical subjects

F De Carlo

Publications and source records attributed to F De Carlo.

15 recordsLinked to original sources
PubMed2006

A completely automated CAD system for mass detection in a large mammographic database.

Mass localization plays a crucial role in computer-aided detection (CAD) systems for the classification of suspicious regions in mammograms. In this article we present a completely automated classification system for the detection of masses in digitized mammographic images. The tool system we discuss consists in three processing levels: (a) Image segmentation for the localization of regions of interest (ROIs). This step relies on an iterative dynamical threshold algorithm able to select iso-intensity closed contours around gray level maxima of the mammogram. (b) ROI characterization by means of textural features computed from the gray tone spatial dependence matrix (GTSDM), containing second-order spatial statistics information on the pixel gray level intensity. As the images under study were recorded in different centers and with different machine settings, eight GTSDM features were selected so as to be invariant under monotonic transformation. In this way, the images do not need to be normalized, as the adopted features depend on the texture only, rather than on the gray tone levels, too. (c) ROI classification by means of a neural network, with supervision provided by the radiologist's diagnosis. The CAD system was evaluated on a large database of 3369 mammographic images [2307 negative, 1062 pathological (or positive), containing at least one confirmed mass, as diagnosed by an expert radiologist]. To assess the performance of the system, receiver operating characteristic (ROC) and free-response ROC analysis were employed. The area under the ROC curve was found to be Az = 0.783 +/- 0.008 for the ROI-based classification. When evaluating the accuracy of the CAD against the radiologist-drawn boundaries, 4.23 false positives per image are found at 80% of mass sensitivity.

Algorithms↗
PubMed2004

Topographic classification of EEG patterns in Huntington's disease.

The aim of this study is to perform a topographic classification of electroencephalographic (EEG) patterns in subjects affected by the Huntington's disease (HD). The alpha activity is a discriminating feature for HD, as its amplitude reduction turns out to be a clear mark of the illness. When used as input variable to a supervised neural network, a good classification of pathological patterns and control ones is achieved with high values of sensitivity and specificity. It should be useful to get more insight into the local discriminating capabilities of the alpha rhythm by implementing a neural network approach to classify EEG patterns extracted from groups of channels corresponding to specific regions of the scalp. Receiver operating characteristic (ROC) curve analysis enables one to label each region with the value of the area under the curve, thus providing a local significance for HD classification. A reduction of the area when processing regions of the scalp, with respect to the whole, suggests that all channels provide significant contribution to HD pattern discrimination. These results can be interpreted as an effect of an abnormal subcortical modulation of the alpha rhythm, due to the dysfunctional action of the thalamus on the cortical activities. In a further study, morphometric features of thalamus and basal ganglia, evaluated by MRI, will be matched with the electrophysiological findings.

Brain Mapping↗
PubMed2003

Multiple microscopy modalities applied to a sea urchin tooth fragment.

Two synchrotron X-ray microscopy methods, phase-contrast microradiography (the propagation method) and absorption microCT (high-resolution computed tomography or microtomography), and laser-scanning confocal microscopy (visible wavelength) were used to study a fragment of the keel of a tooth of the sea urchin Lytechinus variegatus. Stripes observed in the phase-contrast images of the fragment were also seen in confocal micrographs. MicroCT showed that the stripes were due to two parallel planar arrays of low-absorption channels within the bulk of the keel. In the phase microradiographs, maximum contrast stripes appear when a channel image from one row coincides with a channel image from the second row; otherwise, contrast is minimal. Long channels do not appear to have been observed previously in keels of sea urchin teeth.

Animals↗
PubMed2003

Three-dimensional microarchitecture of the plates (primary, secondary, and carinar process) in the developing tooth of Lytechinus variegatus revealed by synchrotron X-ray absorption microtomography (microCT).

This paper reports the first noninvasive, volumetric study of entire cross-sections of a sea urchin tooth in which the individual calcite structural elements could be resolved. Two cross-sectionally intact fragments of a Lytechinus variegatus tooth were studied with synchrotron microCT (microcomputed tomography) with 1.66 microm voxels (volume elements). These fragments were from the plumula, that is the tooth zone with rapidly increasing levels of mineral; one fragment was from a position aboral of where the keel developed and the second was from the zone where the keel was developing. The primary plates, secondary plates, carinar process plates, prisms, and elements of the lamellar-needle complex were resolved. Comparison of the microCT data with optical micrographs of stained thin sections confirmed the identifications and measured dimensions of the characteristic microarchitectural features. The interplay of reinforcing structures (plates and prisms) was more clearly revealed in the volumetric numerical data sets than in single or sequential slices. While it is well known that the primary plates and prisms in camarodont teeth are situated to improve resistance to bending (which can be termed primary bending), the data presented provide a new understanding of the mechanical role of the carinar process plates, that is, a geometry consistent with that required in the keel to resist lateral or transverse bending of the tooth about a second axis. The increase in robustness of teeth incorporating lateral keel reinforcement suggests that the relative development of carinar processes (toward a geometry similar to that of L. variegatus) is a character which can be used to infer which sea urchins among the stirodonts are most primitive and among the camarodonts which are more primitive.

Animals↗
PubMed2003

Detection of subclinical brain electrical activity changes in Huntington's disease using artificial neural networks.

OBJECTIVE: The aim of this study was to analyze EEG background activity in Huntington's disease (HD) patients and relatives at risk, in relation to CAG repeat size and clinical state, in order to detect an electrophysiological marker of early disease. METHODS: We selected 13 patients and 7 subjects at risk. Thirteen normal subjects, sex- and age-matched, were also evaluated. Artifact-free epochs were selected and analyzed through Fast-Fourier Transform. EEG background activity was tested using both linear analysis and artificial neural network (ANN) classifier in order to evaluate whether EEG abnormalities were linked to functional changes preceding the onset of the disease. RESULTS: The most important EEG classification pattern was the absolute alpha power not correlated with cognitive decline. The ANN correctly classified 11/13 patients and 12/13 normals. Moreover, the neural scores for subjects at risk seemed to be correlated to the expected time before the onset of the disease. CONCLUSIONS: ANN is a very powerful method to discriminate between normals and patients. It could be used as an automatic diagnostic tool. EEG changes in positive gene-carriers for HD confirm an early functional impairment which should be taken into account in the genetic counseling and in the management of the early stages of the disease.

Adult↗
PubMed2000

Clustering data by inhomogeneous chaotic map lattices.

A new approach to clustering, based on the physical properties of inhomogeneous coupled chaotic maps, is presented. A chaotic map is assigned to each data point and short range couplings are introduced. The stationary regime of the system corresponds to a macroscopic attractor independent of the initial conditions. The mutual information between pairs of maps serves to partition the data set in clusters, without prior assumptions about the structure of the underlying distribution of the data. Experiments on simulated and real data sets show the effectiveness of the proposed algorithm.

Journal Article↗
PubMed1991

Prediction of postoperative pulmonary function following thoracic surgery for bronchial carcinoma.

At present surgery is accepted as the most effective mode of therapy for carcinoma of the lung. Because the lack of respiratory reserve is the major determinant of postoperative function, it is useful to identify the patient, who is at significant risk. Eighteen patients with lung cancer (mean age = 56 +/- 6.5 years) were studied preoperatively (preop) and postoperative (postop) (three to four months after lung resection) by spirometry, measurement of arterial blood gases, and quantitative lung scanning (99mTc). A predicted postoperative value of some variables was calculated by the formula: postop value = preop value x % function of regions of lung not resected. The correlation coefficient between the predicted (pred) and postoperatively observed (observ) values VC = vital capacity, FEV1 = forced expiratory volume in 1 second) is: VC pred/VC observ r = 0.83 p less than 0.001 FEV1 pred/FEV1 observ r = 0.82 p less than 0.001. The authors' results agree with earlier reports and show that the method used can accurately predict the postoperative respiratory function in patients undergoing lung resection (pneumonectomy or lobectomy). A predicted FEV1 of 0.8 L does not permit a surgical program, because, below this level, carbon dioxide retention becomes more frequent and exercise intolerance is increasingly severe (poor quality of life). The method proposed to predict the postoperative respiratory function is simple and routinely useful. The authors choose a perfusion instead of ventilation scan, because the former provides similar predicted postoperative data, and can be done routinely.

Carbon Dioxide↗
PubMed1982

[Changes in hematologic parameters in 120 Somalian subjects].

We have studied in Somali subjects (120), compared with 120 Caucasus subjects the hemoglobin, the hematocrit, the number of red cells, the MCV, the MCH and MCHC. The results demonstrate that in Somali subjects have significant reduction of all parameters, and the reasons of those blood disorders in this tropical country must be associated with the scourges of poverty and malnutrition.

Adolescent↗
PubMedDate not supplied

[An acute superior mediastinal syndrome with critical tracheal stenosis due to benign multinodular goiter complicated by intracystic hemorrhage].

Large benign goiter with a cervical and intrathoracic retrotracheal location is uncommon, but troublesome, since it affects the upper mediastinum and usually causes dyspnea, dysphagia or vascular obstruction; on the other hand, a large mediastinal cyst of thyroid origin complicated by a massive, spontaneous hemorrhage is an exceptional event, implicating vital prognosis through an acute tracheal compression. A 45-year-old-man presented all these complications of a previously neglected nodular-cystic goiter, causing an acute respiratory distress. An emergency diagnosis and consequent surgery, in delayed urgency, were performed. This case is presented because of its rarity. Its clinic management is discussed, in the framework of the existing literature.

Acute Disease↗
PubMedDate not supplied

[Gastric ulcer in the infant: clinical contribution].

The authors, after a short review on the etiopathological classification and the clinical exordium of the gastric ulcer in infancy, report a relapsing case nevertheless the therapy with cimetidine and antacid drugs. Furthermore they note the importance of the careful anamnesis and early and repeated occult blood stool tests to value for eventual gastric fiberendoscopy.

Anemia↗
PubMedDate not supplied

[The Guillain-Barré syndrome in childhood].

The authors describe a case day Guillain-Barré syndrome admitted in pediatrics hospital department for asthenia. Approximately an hour after admission, the patient showed dysphagia and respiratory insufficiency and was diagnosed a Guillain-Barré syndrome, successfully treated.

Child↗
PubMedDate not supplied

[A case of persistent fever].

The Authors report a case of difficult diagnosis, clinically characterised by long-term persistent fever. Clinical and laboratory tests led to a first conclusion of a tubercular infection; later of a perisplenic hematoma and the persistence of high inflammatory indices directed to a different diagnosis.

Child↗