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Biomedical subjects

M G Bonetti

Publications and source records attributed to M G Bonetti.

17 recordsLinked to original sources
PubMed1992

Crossed cerebello-cerebral diaschisis: a SPECT study.

A scintigraphic single photon emission computed tomographic (SPECT) evaluation of frontal perfusion alteration was performed in five patients with known cerebellar lesions but with normal supratentorial computed tomographic (CT) or magnetic resonance (MR) scans. A clearly evident asymmetry was found in prefrontal areas in the four subjects with acquired cerebellar damage. The fifth subject, who had congenital left cerebellar hypoplasia, did not show any frontal flow asymmetry. The data support the growing clinical evidence that the cerebellum contributes to the cognitive processes of the frontal lobes and suggest a possible role for SPECT examination in the assessment of functional cognitive impairment in patients with acquired cerebellar lesions.

Adolescent↗
PubMed1991

Right ventricular aneurysm: a new prognostic indicator after a first acute myocardial infarction.

The prognostic implication of a right ventricular aneurysm after a first acute myocardial infarction (AMI) was assessed on a series of 137 AMI patients 12 of whom had a right ventricular aneurysm detected at radionuclide angiocardiography. The follow-up lasted 36 months. Mortality was 50 and 18.4% in patients with and without right ventricular aneurysm, respectively (p less than 0.02). Groups did not differ in age, male-to-female ratio, AMI site, left ventricular ejection fraction (LVEF), peak filling rate (PFR), left ventricular size. A multivariate logistic analysis showed that only three out of ten clinical and functional variables qualified to be independent predictors of death: right ventricular aneurysm (odd ratio = 2.48, confidence limits = 1.21-4.98), LVEF less than 52% (odd ratio = 1.91, confidence limits = 1.03-3.48), abnormal terminal P wave forces (odd ratio = 1.72, confidence limits = 1.07-2.75). The analysis of single case histories did not provide a clue to clarify the reasons accounting for the negative prognostic implication of a right ventricular aneurysm. In conclusion, a significant positive relationship between right ventricular aneurysm and mortality after AMI has been demonstrated; further study is needed to clarify the relevant mechanisms.

Aged↗
PubMed1991

[Diagnostic yield in rhino-sinusal inflammatory pathology: comparison of projective radiology, CT and MR].

In everyday practice, the radiologist is concerned with the diagnosis of inflammatory conditions of the nose and paranasal sinuses. This paper was aimed at evaluating and comparing the diagnostic efficacy of the main diagnostic imaging procedures currently available. Fifty-six patients were studied: 25 with computed radiography (CR) and CT, 21 with CR and MRI (0.22 T resistive magnet), and 10 with CR, CT, and MRI. From the diagnostic point of view, the conventional-like CR image was assumed as analog to the conventional radiographic (RX) one on the basis of previous personal experience. The following elements were separately considered for RX, CR, CT, and MRI: anatomical structure identificability, spatial resolution, dosimetry, time consumption, diagnostic results, and economics. A global performance index was calculated (RX less than 1; CR = 1; MRI ranging 1.2-2.2; CT = 7.3). CR was superior to RX, from both a diagnostic and a dosimetric point of view, but buying the equipment is nowadays expensive. CT and MRI were superior to both RX and CR in the diagnosis of inflammatory conditions of the nose and paranasal sinuses. When an inflammatory condition is unquestionable, MRI is more accurate than CT, but the latter (thanks to its optimal documentation of both bony walls and soft tissues) is superior to MRI in the differential diagnosis of a generic disease of the nose and paranasal sinuses--that is, when the inflammatory nature is questionable. MRI limitations were poor visualization of bone walls, high cost, and poor access. Thus, CT emerged as the technique of choice, thanks to its diagnostic results, easy access and low cost, with a negligible radiation dose to patients.

Adult↗
PubMed1991

[Vertebral collapse model: combined diagnostic imaging].

Ninety-eight consecutive patients with 344 collapsed vertebrae underwent conventional and/or digital radiography and MRI. Vertebral collapse was due to osteopenia (16 cases), trauma (17 cases), and vertebral osteonecrosis (3 cases). Other causes were: spondylodiscitis (9 patients), primary neoplasm (4 patients), metastases (37 patients), and hemomyelopathies (7 patients); 5 patients bore vertebral angiomas. Sixty-three patients also underwent CT and 25 bone scintigraphy. As far as collapsed vertebral endplates are concerned, according to a previous classification, outcomes were divided into 4 groups. Type 1 (focal concave collapse) was observed in 10% of benign lesions and in 1% of malignant ones; type 2 (diffuse concave collapse) in 24% of benign and in 16% of malignant lesions; type 3 (focal collapse with an acute angle) in 11% of benign and malignant lesions, and type 4 (diffuse collapse with an acute angle) in 11% of benign and in 26% of malignant lesions. Neural arch involvement was observed in 3% of benign lesions and in 16% of malignant ones; paravertebral soft-tissue involvement in 6% of benign and in 29% of malignant lesions; vertebral canal involvement in 11% of benign lesions and in 20% of malignant ones. The intervertebral disk proximal to vertebral collapse was more involved in benign lesions (24%) than in malignant ones (8%). MR signal followed 4 main patterns: low signal on T1-weighted images and high signal on proton-density and T2-weighted images (2% of benign lesions, 49% of malignant ones), low signal on all sequences (7% of benign lesions and 25% of malignant ones), isointense signal on all sequences (50% of benign and 21% of malignant lesions), and high signal on all sequences (41% of benign lesions and 0% of malignant ones).

Adolescent↗
PubMed1990

Cardiac arrhythmias and left ventricular function in respiratory failure from chronic obstructive pulmonary disease.

In 22 patients with COPD, we studied the relationship between left ventricular function and cardiac arrhythmias. Ventricular arrhythmias were detected on a 24-h ECG recorded at the beginning of the observation period and after a stable improvement of RF. Left ventricular function was evaluated by equilibrium-gated radionuclide angiocardiography measuring LVEF, PER and PFR. We found a significant decrease in the arrhythmia score after improvement of RF; LVEF and PFR were slightly depressed in six and nine patients, respectively. A "step-up" multiple regression analysis revealed a significant inverse correlation between PFR and ventricular arrhythmias during worsened RF, whereas LVEF, arterial blood gases and clinical data were not significantly predictive variables. Thus, a depressed left ventricular diastolic performance seems to be a predictive factor for arrhythmias during RF from COPD. The poor definition of the statistical model suggests that other presently unknown factors contribute to the genesis of ventricular arrhythmias.

Arrhythmias, Cardiac↗
PubMed1990

[Preliminary experience of the study of the hand using digital radiology with photo-excitable phosphors and direct magnification. Comparison with the traditional high resolution technique].

Photostimulable phosphor computed radiography (CR) is a new technique. The authors applied direct magnification CR to hand study (IP matrix: 1770 x 2370), and compared the results with conventional radiography ones (high MTF industrial type film, without screens, 5 x optic enlargement reading). In both cases, a mammographic unit was employed for acquiring the images. Thirty patients affected with renal osteodystrophy, psoriatic arthropathy or rheumatoid arthritis, and 20 normal subjects were examined. Digital images were processed by a particular sensitometry curve and spatial filtering with unlinear unsharp masking: we obtained good visualization of small lesions (subperiosteal resorption, cortical bone tunnelling, minute periosteal necrosis), not inferior to that obtained with conventional techniques. CR has further advantages, such as low economic and biological cost, wide exposure and recording range, image processing, easy archiving and networking.

Arthritis, Psoriatic↗
PubMed1990

[High-resolution rapid multiplanar reconstructions in the CT study of the spine. Our experience].

The authors describe the utility of fast and high-resolution multiplanar CT reconstructions in the study of the rachis. Their experience is reported with an up-to-date software with 2 different representation modalities (CMR 01B). A "package" of contiguous axial images is obtained in a standard way; the images are then reformatted by computer to obtain (in just a few seconds) high-resolution reconstructed images in different planes (coronal, sagittal, and oblique). In the authors' opinion the method, in spite of some limitations, yields in most cases additional information which is not provided by conventional CT. Reconstructed images are most useful in the study of complex anatomical structures (such as vertebral metameres) along their anatomical planes.

Humans↗
PubMed1990

[Comparison of traditional methods and digital technics in the study of the biliary and pancreatic systems using endoscopic retrograde cholangiopancreatography (ERCP)].

ERCP holds a key role in the diagnosis of pancreatic-biliary disease. In this technical paper the authors report their experience with computed radiography (CR) in ERCP diagnostic imaging. A stimulable phosphor system was employed (Toshiba TCR-201). Fifteen pancreatic-biliary patients were studied with both conventional and CR techniques. With the same diagnostic output and radiological system, CR was superior to conventional technique in: dramatic exposure-time reduction, image post-processing (exposure error amendment, contrast change, spatial filtering, zooming, gray-scale inversion, etc.), patient exposure reduction, and digital archiving.

Aged↗
PubMed1989

[Radiological study of the thorax. Evaluation of efficacy-efficiency of a large-field image intensifier in mass screening].

Chest X-ray is the most frequent examination in radiology and accounts for a considerable portion of total population radiation exposure, mostly in screening programs. The ideal radiographic system is the one providing the best image quality together with the lowest dose to the patient, at a low cost. In this paper the authors analyze the potentials of a new chest X-ray examination unit equipped with a large-screen image intensifier (TS 57-Siemens). Two-thousand subjects were examined with this unit. The technical aspects of everyday practice are analyzed from the radiologist's point of view, together with the dose to the patient, image quality, and costs.

Adult↗
PubMed1987

[Assessment of uteroplacental circulation with radioisotopes].

The authors have evaluated placental blood flow using a non-invasive radioisotopic approach, with the intravenous administration of 1 mCi 113mIn. The method is evaluated in 20 normal pregnancies, in 24 patients with intrauterine growth retardation, in 8 patients with iso-Rh-immunization and in 9 patients with gestational diabetes. In the group with intrauterine growth retardation 2 pregnancies with extensive fetal malformations were included. In one case without evident histological placental alteration the index was 3.94 at 34 weeks of gestation and 5.62 at 36 weeks of gestation. In the second one with placental infarcts the index was 3.46 at 38 weeks of gestation. Normal pregnancies showed a flow index of 5.50 +/- 1.57 (1 s.d.) units compared to the pathological pregnancies value of 2.74 +/- 0.90 (1 s.d.) units. (p less than 0.001). The conclusions drawn are: The method is very well suited to clinical evaluation of placental blood flow. The evaluation of placental blood flow cannot be directly equated with fetal development as it is not its only determinant. This method is a indirect index of placental function in small for gestational age fetuses with malformations.

Congenital Abnormalities↗
PubMed1986

Correlation of functional parameters derived by equilibrium radionuclide angiocardiography and left ventricular size in patients with old myocardial infarction.

A total of 131 patients with old (over 6 months) myocardial infarction (MI) and 18 normal subjects underwent equilibrium radionuclide angiocardiography at rest (rERNA). The following rERNA parameters were assessed: left ventricular ejection fraction (LVEF), peak ejection rate (PER), peak filling rate (PFR), regional wall motion and a left ventricular size index. The patients with old MI were divided into four groups (I to IV) according to increasing left ventricular (LV) size, and the behaviour of the numerical parameters (LVEF, PER, PFR) was evaluated in each group. LVEF proved to be the most sensitive numerical parameter of overall LV performance. PFR decreased significantly from group I to group III but not from group III to group IV, suggesting that for extreme degrees of left ventricular enlargement some compensatory mechanism acts to prevent a too large fall in LV compliance. The effects of the site of the previous MI on LV performance were also evaluated. Both LV size and performance were least affected by postero-inferior MI. The LVEF was, however, a better predictor of LV size than the site of the MI.

Adult↗
PubMed1986

Equilibrium radionuclide angiocardiography to select inotropic therapy in patients with left ventricular aneurysm.

Fourteen patients with postinfarctual ventricular aneurysm underwent equilibrium radionuclide angiocardiography at rest (ERNA) before and after oral digoxin administration in order to evaluate the effects of increasing myocardial contractility upon both ventricular aneurysm mechanical behaviour and global ventricular function. The ejection fraction (EF) was not significantly affected by digoxin therapy. However, digoxin induced changes in EF (delta EF) correlated inversely with changes in aneurysm size and directly with changes in the extent of the hypokinetic area. Two types of aneurysm were observed: high-compliance aneurysm the size of which increased after digoxin administration while both EF and the extent of the hypokinetic area fell, and low compliance aneurysm for which opposite changes occurred. This different behaviour of ventricular aneurysm may have important practical implications as surgery would be probably more effective than medical treatment in improving resting ventricular function in patients with high-compliance aneurysm.

Adult↗