Marco Paterni

Università di Pisa, Pisa, Tuscany, Italy

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Publications (84)278.54 Total impact

  • M. Demi · M. Paterni · V. Gemignani · A. Benassi
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    ABSTRACT: In this paper we show how the generalization of the first absolute central moment gives rise to a class of nonlinear filters and how they can be used in image analysis to enhance lines, edges, corners and intersections between different discontinuities. Since the filters are nonlinear the recovered edge information can be also combined to obtain information that would not be obtained by varying the parameters of the original filter. Furthermore, we show how a mass center of the first absolute central moment can be defined and how this can be used to develop a new contour tracking procedure. The mass centers computed at the points of a given approximate starting contour are closer to the 'true' contour than the points of the starting contour. Therefore, the final contour can be localized by iteratively computing the mass centers of the first absolute central moment.
    No preview · Article · Mar 2015

  • No preview · Article · Dec 2014 · Artery Research
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    ABSTRACT: Context Hyperglycemia is associated with a higher carotid intima-media thickness (IMT), however it is not established whether this increase reflects early atherosclerotic changes or adaptive remodeling responding to hyperglycemia-induced alteration in mechanical properties of the arterial wall. Objective Aim of this study was to compare carotid geometry and circumferential wall stress between patients with type 2 diabetes mellitus (T2DM) and healthy controls, and to evaluate the associations between chronic glucose exposure and measures of arterial structure and function. Design Case-control and cross-sectional study Setting Institutional practice Participants One hundred thirty-three T2DM patients free of cardiovascular complications and 133 healthy controls with normal glucose metabolism, matched for sex, age, body mass index Main Outcome Measures Common carotid artery (CCA) IMT, luminal diameter, wave speed (WS) and local pulse pressure (PP) Results As compared to controls, T2DM patients had higher (P<0.0001) CCA IMT (640±81 vs 709±118 μ m), luminal diameter (6.12±0.67 vs 6.69±0.56 mm) and brachial PP (47±7 vs 57±12 mmHg), whereas luminal radius to IMT ratio (4.8±0.7 vs 4.8±0.8, P=0.57) and circumferential wall stress (49.0±8.3 vs 50.6±10.3 kPa, P=0.26) were comparable between the two groups. In T2DM patients, glycosylated hemoglobin was independently related to CCA WS and local PP, but not to IMT that was determined by age, local PP and luminal diameter. Conclusions This study suggests that increase in IMT associated with a higher glucose exposure might reflect an adaptive remodeling counteracting raise in pulsatile strain and preventing increment in circumferential wall stress caused by luminal enlargement of stiff arteries.
    Full-text · Article · Jul 2014 · Journal of Clinical Endocrinology & Metabolism

  • No preview · Article · Jun 2011 · Journal of Hypertension

  • No preview · Article · Sep 2008 · The Journal of Clinical Endocrinology and Metabolism
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    ABSTRACT: An independent association between obesity and preclinical carotid atherosclerosis has been demonstrated, however, the pathophysiological links were not clearly established. Body composition (BC) influences systemic hemodynamics and may participate in the remodeling of common carotid artery (CCA), independently of risk factors. This study evaluated the association between CCA structure and BC in a large population of healthy subjects. This was a cross-sectional study. The study was conducted at 19 European centers. The study included 627 healthy subjects (252 men, age 30-60 yr, body mass index 17-40 kg/m2). CCA luminal diameter and intima-media thickness were measured on digitized ultrasound images. Acoustic properties of CCA wall were evaluated by digital densitometric analysis and described in terms of mean gray level. BC was assessed by electrical bioimpedance. Insulin sensitivity (euglycemic hyperinsulinemic clamp) and plasma adiponectin levels were measured. Associations between CCA structure, age, BC, and metabolic and atherosclerotic risk factors were analyzed by multivariate regression models. Independent factors affecting CCA diameter were fat-free mass and waist girth (standardized r = 0.44 and 0.12; P < 0.01 and < 0.0001; R2 = 0.35); independent correlates of intima-media thickness were age, CCA diameter, systolic blood pressure, and low-density lipoprotein-cholesterol (standardized r = 0.39, 0.25, 0.10, and 0.14; P < 0.005-0.0001; R2 = 0.40). The mean gray level of carotid wall was independently associated with age and waist girth (standardized r = 0.23 and 0.12; P < 0.0001 and = 0.001; R2 = 0.30). Findings of this cross-sectional study suggest that BC modulates CCA diameter, and may induce adaptive changes in carotid wall thickness, independently of metabolic and atherosclerotic factors. Central adiposity modifies the acoustic properties of carotid wall.
    No preview · Article · Aug 2008 · Journal of Clinical Endocrinology & Metabolism
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    ABSTRACT: Regular endurance exercise has been shown to reduce the age-related increase in arterial stiffness that is thought to contribute to cardiovascular risk. The aim of this study was to evaluate the influence of age and habitual physical activity on carotid artery wall thickness and stiffness in a population of young to middle-age subjects at low cardiovascular risk. The study population consisted of 432 healthy subjects (166 men; mean+/-SD age, 43+/-8 years; range, 30 to 60 years) free of carotid atherosclerosis and with low coronary heart disease risk, as determined by the Framingham prediction score sheet. All subjects underwent B-mode ultrasonography of the extracranial carotid arteries and physical activity assessment by actigraph, an accelerometer capable of monitoring the intensity and duration of body movements. The intima-media thickness of the common carotid artery was measured on ultrasound images, along with systodiastolic changes in luminal diameter, and indices of carotid stiffness were calculated. Intima-media thickness and carotid stiffness increased with age in both men and women (r=0.24 to 0.52, P<0.001). The magnitude of objectively assessed daily physical activity was negatively related to indices of carotid stiffness (r from -0.20 to -0.25, P<0.001) but not to intima-media thickness. In multivariate regression analyses that included several cardiovascular risk factors such as obesity, blood pressure, plasma lipids, and smoking habits, age and physical activity were independently related to carotid stiffness. This study provides cross-sectional evidence that habitual physical activity is inversely related to the age-dependent increase in carotid wall stiffness in a young to middle-age population at low risk.
    Full-text · Article · Sep 2007 · Stroke

  • No preview · Article · Sep 2007 · Artery Research
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    ABSTRACT: In the hypertensive heart, epicardial arteries are not enlarged, despite increased total coronary flow related to augmented cardiac workload, wall stress, and left ventricular (LV) mass. The aims of this study were to assess the impact of different hemodynamic factors and LV mass on baseline left main coronary artery (LMA) size in hypertensive LV hypertrophy (LVH) and physiologic LVH, used as a pressure-independent model of hypertrophy. In 104 subjects without coronary disease (26 normotensive subjects without LVH, 15 athletes with physiologic LVH, and 63 untreated hypertensive subjects [28 without and 35 with LVH]), LMA size and coronary flow reserve (CFR) were measured by transesophageal echocardiography, and LV mass, volumes, stroke work, and wall stress were measured by transthoracic echocardiography. The LMA area in normotensive control subjects, athletes, and hypertensive subjects without and with LVH was 13.2 +/- 4.2, 17.5 +/- 2.9, 10.1 +/- 3.2 and 13.1 +/- 3.9 mm(2). In normotensive control subjects, LMA size increased with body surface area, rate-pressure product, stroke work, and LV mass or wall thickness (r = 0.39, 0.39, 0.47 and 0.67 or 0.62, P < .05-0.01). In athletes with physiologic LVH, LMA area increased with CFR (0.65, P < .01). In the whole hypertensive population, LMA lumen increased with LV mass (r = 0.40, P < .01), and decreased with office systolic blood pressure (r = -0.48, P < .01). In the hypertensive LVH, baseline LMA area is not increased and is inversely related to office systolic blood pressure. In the physiologic LVH, increase in baseline LMA size seems to reflect effect of high-flow stimuli.
    No preview · Article · Mar 2007 · American Journal of Hypertension
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    Full-text · Article · Jan 2005
  • M. Paterni · F. Bartolomucci · C. Morizzo · C. Palombo

    No preview · Article · Jan 2005 · High Blood Pressure & Cardiovascular Prevention
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    ABSTRACT: Aims of this study were to: (1) demonstrate whether quantitative myocardial contrast echocardiography could detect an index of myocardial blood flow reserve through the analysis of refilling curves generated by microbubble transit into myocardium both at rest and after vasodilatation induced by dipyridamole; and (2) explore with this method myocardial microcirculatory function in two different models (ie, patients with essential hypertension and control subjects). Two groups of strictly age-matched men were studied (case-control study): 12 patients who were adults (28.2 +/- 0.2 years) and asymptomatic with never-treated essential hypertension, a mild degree of left ventricular hypertrophy, and normal left ventricular function; and 12 control subjects. Quantitative myocardial contrast echocardiography was performed in all study participants. We used second-generation ultrasound microbubbles as echocardiography contrast agent. Real-time color-coded power modulation was performed with a phased-array system interfaced to a S3 transducer (1.3-3.6 MHz). In control subjects there was little increase in myocardial blood volume (30%) between basal and hyperemic status (P <.05); in patients with hypertension this parameter increased by 22% (P <.05). Myocardial blood velocity increased after dipyridamole by 270% in control subjects (P <.01), whereas for patients with hypertension this parameter increased only by 150% (P <.02). The index of myocardial blood flow reserve was significantly lower for patients with hypertension than in control subjects (3.3 +/- 0.3 vs 4.4 +/- 0.3, respectively; P <.01). Results of our study documented that myocardial microcirculation in young adult patients with hypertension showed an early impairment in the vasodilatation capacity of the resistance arterioles under dipyridamole-induced hyperemia, as demonstrated by a reduction of myocardial blood flow reserve. Myocardial blood velocity increased after dipyridamole induction in control subjects, whereas patients with hypertension showed a significantly lesser increase. Myocardial blood flow reserve was significantly lower for patients with hypertension because of an early impairment in vasodilatation capacity of resistance arterioles under dipyridamole-induced hyperemia.
    No preview · Article · Oct 2004 · Journal of the American Society of Echocardiography

  • No preview · Article · Jun 2004 · Journal of Hypertension

  • No preview · Article · Jun 2004 · Journal of Hypertension

  • No preview · Article · Jun 2004 · Journal of Hypertension
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    V. Gemignani · M. Paterni · A. Benassi · M. Demi
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    ABSTRACT: In this paper, a new system for real time contour tracking is presented. If a rough contour of the desired structure is available on the first image of a sequence, the system can automatically outline the contours on the subsequent images at video rate. The method we used is based on a new edge detector which was obtained by the generalization of the first order absolute central moment operator. The new algorithm proved to be very robust to noise and fast enough to be implemented in real time. The contour tracking procedure was implemented on an integrated software/hardware platform composed of a personal computer equipped with a digital signal processing board. The system can capture an analog video signal with a resolution of 512×512 pixels, 25 frames/s, process the data and display the results in real time. A graphical user interface is also available to interact with the system. Tests on images of the descending thoracic aorta and of a carotid, recorded by echocardiography, are reported. The cross-sectional area of the aorta and the diameter of the carotid were computed in real time and plotted on the user interface. The system proved to be a useful tool for the investigation of vascular mechanisms.
    Full-text · Article · Apr 2004 · Real-Time Imaging
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    ABSTRACT: We investigated whether differences in cellular composition of the shoulder region of carotid plaque, a cell-rich, debris-free area, can be revealed with computer-driven analysis of ultrasound scans. In 26 patients referred for carotid endarterectomy, the shoulder region of plaque eligible for surgical removal was identified with ultrasound scanning. Digital images were obtained and evaluated with a specially developed computer-driven system (Medical Image Processing [MIP]). The gray level distribution of the region of interest (ROI), along with some statistical parameters exploring the spatial distribution of pixels, such as entropy and second angular moment, were analyzed. In the specimen retrieved at surgery, the area corresponding to the ROI was selected. Cryosections were tested at immunocytochemistry with monoclonal antibodies specific to smooth muscle cells (SMCs), macrophages), and lymphocytes. Computerized image analysis was performed to quantify each cellular component of the lesion. Mean gray levels were related positively to the content of SMCs (r = 0.576, P =.002) and negatively to the content of macrophages (r = -0.555, P =.003). Lymphocytes did not show any correlation. Prevalence of SMCs, expressed as the ratio SMC/(SMC + macrophages), was related positively with entropy (r = 0.517, P =.007) and negatively with the second angular moment (r = -0.422, P =.032). The quartiles of gray level were useful for detecting significant differences in terms of cellular composition. Some cellular features of the shoulder region of plaque are associated with specific videodensitometric patterns evaluated with MIP. This approach enables in vivo noninvasive prediction and monitoring of cell composition of the shoulder region, and could be extended to study of the thickened intima.
    Full-text · Article · Jan 2004 · Journal of Vascular Surgery
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    Preview · Article · Dec 2003 · European Heart Journal – Cardiovascular Imaging
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    M. Paterni · F. Faita · A. Benassi · M. Demi
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    ABSTRACT: Echographic imaging plays a decisive role in diagnostics. However, the narrow field of view which is obtainable with an ultrasound probe can be a serious drawback. Techniques are needed to extend the field of view by reconstructing panoramic images from image sequences. In this paper the results obtained with the algorithm developed by H. Bulthof et al. are illustrated. The algorithm was used to estimate the motion of the probe between every pair of consecutive frames of echographic sequences. Subsequently, the gray level map of every single frame of the sequence was translated according to the estimated motion and added to the gray level maps of the previous frames with a mean operation. Three kinds of test sequences were used to evaluate the algorithm performances: simulated sequences, sequences of a calibration phantom and sequences of brachial arteries.
    Full-text · Conference Paper · Oct 2003
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    ABSTRACT: The study was carried out in two different models of left ventricular hypertrophy: athlete's heart and essential arterial hypertension. Three groups of strictly age-matched males were studied: one group of 10 young adult untreated essential hypertensive patients (H), a second group of 10 athletes (A), and a group of 10 healthy individuals as controls (C). A Sonos 5500 echograph with S4 harmonic transducer was used with Levovist (ultrasonic tracer) before and after dipyridamole injection; digitised images of quantitative myocardial contrast echocardiography were collected with Power Harmonic Doppler. Angio images were analysed using dedicated PC software by placing a region-of-interest on the septum. Peak intensity, half-time (HT), the area under the curve of appearance and disappearance of microbubbles at 2/3 of PI, both in absolute and indexed values (/LVMi), were sampled. The per cent increase of PI after dipyridamole was significantly higher in C (+73%, P < 0.01) than in H (+31%) and in A (+33%) (P < 0.05). The area of appearance was significantly lower in H in comparison with C and A, both at rest and after vasodilatation. The disappearance area after dipyridamole was significantly higher in C and in A (+124%) than in H (+104%) (P < 0.05). Some hypothesis could be made: an impairment in the coronary microcirculatory function in hypertensive patients could be because of an in-crease in the arteriolar resistance. Angiogenesis and several different functional adaptations are the mechanisms that allow an optimal distribution of oxygen and of substrates to the hypertrophied myocardium of the athletes.
    Full-text · Article · May 2003 · Journal of Human Hypertension

Publication Stats

1k Citations
278.54 Total Impact Points


  • 1993-2014
    • Università di Pisa
      • Department of Clinical and Experimental Medicine
      Pisa, Tuscany, Italy
  • 1995-2008
    • Italian National Research Council
      • Institute of Clinical Physiology IFC
      Roma, Latium, Italy
  • 2001
    • Università degli Studi del Sannio
      Benevento, Campania, Italy
    • Università degli Studi G. d'Annunzio Chieti e Pescara
      Chieta, Abruzzo, Italy