Search

Over the past decade near infrared spectroscopy (NIRS) and imaging are rapidly evolving for a large number of new clinical applications. These techniques, based upon near-infrared light transmission through biological tissues, aim to monitor the hemoglobin and myoglobin concentration changes due to particular physiological state. Clinical applications regard, for instance, the monitoring of muscles and cerebral oxygenation, functional brain activation studies and heart perfusion research. Recently, some works presented tissue oxygenation studies in beating or arrested isolated small animal hearts. Lately, diffuse optical tomography (DOT) has been developed: it employs tissue arrays of infrared sources and detectors to obtain maps of optical properties of illuminated tissues. In this paper we present the design and realization of a first prototype of a near infrared tomograph for the myocardial perfusion analysis of isolated small animal hearts. Preliminary tests have been performed using some phantoms with different NIR absorption coefficients and an isolated rat heart. The device is able to distinguish objects with different absorption coefficients in the imaging area and to provide 2D map of small animals heart IR light absorption.

Continuous monitoring and analysis of vital parameters like SO2, heart frequency, breathing frequency is important for the prevention and management of cardiac heart failure. The cardiac sentinel allows continuous monitoring and recording of these parameters and automatic transmission of the collected data to the clinical server via an inbuilt GSM modem.

A Web application was built to support cardiologist's medical decision-making. Main components are: 1. a 3D-dynamic virtual heart, integrating the single patient's cardiac and coronary abnormalities. 2. Estimation of patient's outcome on the basis of historical data analysis on the subpopulation/s with the closest similarity to the patient's risk profile. 3. Same derived from published clinical controlled trials. 4. External web links to international guidelines, risk charts and epidemiological surveys. Each patient is characterized by over one-hundred parameters belonging to anamnesis, test results, final diagnosis, therapy and follow-up. Historical data were retrieved from the Institute's cardiology database-containing more than 11,000 patients hospitalized in the last 30 years and systematically followed up for 10 years - and were graphically rendered. Cardiologists have expressed appreciation toward the project as it gives easy access to a wide range of data, precious for medical decision-making and important for research protocols and clinical and administrative patient management.

To quantify the heterogeneity of contrast enhancement inside left ventricular (LV) cavity, 10 patients were studied by harmonic intermittent power Doppler following venous echo contrast administration. Regions of interest were drawn in the LV cavity along the main axis and transversally to derive time-intensity curves. Signal intensity at plateau (A) significantly decreased along LV longitudinal axis: from apex (48/spl plusmn/6 dB), to center (41/spl plusmn/7) and base (31/spl plusmn/9 dB, p

We have developed a system that integrates, through a virtual 3D-dynamic heart model, all the pertinent clinical and instrumental information obtained for patients hospitalized for suspected or documented ischemic heart disease (IHD). In the present study we retrospectively compared the diagnosis formulated by the cardiologist in the discharge record with that automatically provided by the system. Divergences were found in 27% of the 110 patients studied and classified into four types: I) inability of the system to provide the correct diagnosis because of the lack of pertinent diagnostic parameters in the model (3%), a cardiologist's diagnosis which was either II) not supported by objective data (3%), III) in conflict with the available information (10%), or IV) incomplete (11%). An experimental trial has been started in which the cardiologist in charge of the patient uses the automatic system during the diagnostic process and compilation of the discharge report.

A cardiological multidimensional database, Image, was implemented in the 1982 to store the most important data obtained during hospitalization of patients affected by cardiovascular disease. The database is populated when the patient is discharge and subsequently enriched with follow up data. Patients are followed for at least five years, maximum for ten years. At the moment database contains almost 10000 patients. In the population observed over the twenty years changes in demographic, clinical manifestations and therapeutic approaches of cardiovascular disease are found Follow up data allow to correlate treatment approaches with prognosis. The long-term Image database results essential 1) to obtain clinical data integration useful for playback consultation for health care or research purposes 2) to obtain epidemiological information on diseases 3) to follow the different impact of therapeutic procedures on prognosis.

Growing progress in the understanding of cardiac physiopathology requires multiparametric approach to diagnosis and management of diseases. However, the number of information the heterogeneity of its source, and the technical terminology itself make the process of medical decision and its appraisal difficult. In order to facilitate integration and communication the most significant information on the individual cardiac patient was concentrated in a 3D dynamic heart model able to easily disclose left ventricular anatomical functional and perfusional abnormalities as well as their spatial relationship with coronary lesions.

A model of the topology of coronary perfusion based on the theory of self-organizing maps is proposed. The model is based on general physical assumptions about the basic mechanisms of the spatial organization of arterial networks. On the basis of such assumptions the authors obtain a cost functional whose optimization leads to the computation of model parameters. Application to X-ray coronary angiography is described, a particular attention being paid to the assessment of the regions potentially perfused by each vessel. Moreover, in order to account for the potential adaptation of the heart vascular tree to pathological conditions such as vessel lumen reduction, the self-adaptation capabilities of the proposed model are analyzed. Preliminary results from clinical data are described.

Digital communication in medical image consulting is challenged by information overflow. This is true in particular for cardioangiographic images that require 25 frame/sec and matrices of 512*512 pixels. Based on multimedia commercial platform, a system for simultaneous digitising of biological signals, audio tracks and image sequences, has been developed in the catheterization laboratory. The work plan was subdivided in: -immediate retrieving and consulting of multimedia documents, -multimedia relational archiving; -communication tools for host consultants. The following services are already operative in the routine clinical activity which have been experienced on over 50 catheterization procedures: real time acquisition of long angiographic cine sequences; local editing and quantitative evaluation; transmission of essential elementary data (clinical data, hemodynamic and angiographic findings including 10 descriptive images) for local hospital information system and LAN services; teleconsulting and desktop sharing services for exchanging information and images of interest among remote experts; videoconferencing; transmission of complete angiographic examinations in digital form; standard communication protocol for the transmission of resulting data on an Internet backbone; hi-speed telematics services (i.e., videoconferencing and transfer of image sequences) operating on broad-band networks, such as local and metropolitan area networks. Cardiologists, radiologists, computer scientists, engineers and national companies are contributing to the development of an user-friendly system continuously updated according to technical and scientific progress.

We report on the use of the entire coronary tree as a natural descriptor of heart motion. The displacement field of the vascular net is estimated by tracking its geometrical and topological features. Afterwards, the shape and Me movement of epicardium are recovered by using a deformable model derived on the basis of general physical assumptions. The heart surface and the related motion field are represented through a spherical harmonic series. This permits a compact analytical description which is global and focal at the same time and is well suited for a multi-level analysis. Experimental results on clinical angiographic data are illustrated.

In previous studies, we have reported on: a) the three-dimensional reconstruction of coronary trees from bi-plane angiography, and b) the recovery of heart surface from epicardial vessels. On the ground of such works, we have developed a computational model of the spatial distribution of myocardial vascularization. The proposed model is based a on self-organizing neural network of the Kohonen's type. This allows the computation of an optimal topology-preserving map of the arterial tree onto the epicardium. The availability of such a map permits the computation of the areas at risk directly from X-ray angiography. Preliminary results from clinical data are illustrated.

To study the influence of altitude exposure on heart rate variability (HRV) and cardiac ventricular function, 11 male climbers performed 24-hour ECG and echocardiographic evaluation during an expedition to Mount Everest. Recordings were done as soon as they reached the altitude of 5000 m, after at least 15 days of acclimatization and at sea level (both before and after the expedition). HRV indices were computed (in the time and frequency domains) on the RR time series, and major cardiac measures were calculated from the best echocardiographic view. Significant changes in HRV and other cardiac indices were detected after altitude exposure. Altitude distress induced tachycardia and reduced some HRV indices. The respiratory pattern was used to document sleep apnea, which greatly interferes with RR-interval time series. It was concluded that altitude distress modifies the cardiac function, whose interference with the heart-rate reflex could explain the HRV changes.

The authors' aim was to validate a graphic model conceived for integrating and transferring information on cardiac abnormalities of patients with ischemic heart disease (IHD). Information derived from anamnesis, ECG and invasive and non-invasive imaging techniques were synthesized in a simple, self-explanatory, color-coded, dynamic, 3D heart. Data from 116 consecutive patients were analyzed. The following features were considered: 1. Expressiveness of the model 2. Incompleteness, conflict and redundancy of data 3. Questionable medical decisions. Immediateness of representation was reached even in very complex cases. Though frequent missing information was critical for the patient management in few cases only. Conflicts on regional motility were frequent but clinically marginal. In 5% conflicts on the diagnosis of ischemia or necrosis and were potentially relevant. Finally, 12% of revascularizations were performed in absence of stenosis-related ischemia or hibernation.

To study the influence of altitude exposure on heart rate variability (HRV) and the possible detection of apnea by ECG 11 male climbers performed 24-hour ECG and respiratory signal monitoring during an expedition to the Everest. Recordings were done as soon as they reached the altitude (=>5000 m, P1), after at least 15 days of acclimatization (P2) and at sea level (before and after the expedition, B1, B2). HRV indices were computed on the RR time series, and their mean hourly values were fitted by a harmonic regression model to quantify the circadian periodic structure. Significant changes of HPV indices were detected after altitude exposure: altitude distress induces tachycardia, reduces HRV indices and blunts circadian heart rate variability. Respiratory pattern greatly interferes with RR interval time series.