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Biomedical subjects

M G Bonetti

Publications and source records attributed to M G Bonetti.

At least 19 recordsLinked to original sources
PubMed1997

Rhinopharyngoscopy, computed tomography and magnetic resonance imaging.

Rhinitis is defined as nasal congestion, sneezing, itching and rhinorrhoea, recently classified as allergic, infective, structural or "other". The increasing employment of flexible rhynolaringoscopy may represent one of the most useful diagnostic tools in the complex differential diagnosis between allergic and nonallergic rhinitis. Furthermore, chronic allergic rhinitis, with secondary impairment of mucociliary clearance and the plethora of frequent anatomical variations, especially in the ostiomeatal complex, appear to predispose the patient to recurrent rhinosinusitis. In the last two decades, a better understanding of mucociliary clearance of nasal cavity and paranasal sinuses has shifted the attention from the maxillary sinuses to the area of the antherior ethmoid sinuses. Plain film radiographic examination, the historical standard, due to its inability to individualize ethmoid and sphenoid disease, is being rapidly supplanted by computed tomography and magnetic resonance imaging in the diagnosis of rhinosinusitis. In allergic and non-allergic rhinitis the diagnostic role of magnetic resonance imaging and computed tomography is still under debate. Computed tomography and magnetic resonance imaging are more efficient in demonstrating the bone wall, mucosal layer and sinus content than classical and computerized radiology; they have a higher diagnostic performance index in spite of a higher cost and, for computed tomography, a higher radiation dose.

Diagnosis, Differential↗
PubMed1996

Hepatic iron overload in thalassemic patients: proposal and validation of an MRI method of assessment.

BACKGROUND: A simple, accurate, reproducible and noninvasive method of body iron overload assessment would be of great clinical use. Objective. The purpose of the study was the implementation of a 0. 5-T MRI method for liver iron overload measurement. MATERIALS AND METHODS: Thirty patients with thalassemia major took part in the study. Liver and paraspinal muscle signal intensity (SI) measurements were performed on T1-weighted images and normalized on a standard phantom, and a subjective hemochromatosis grading scale was made on both T1- and T2-weighted images. Serum ferritin levels and tissue iron from liver biopsy specimens were determined for comparison. RESULTS: A close correlation was found between bioptic liver iron and both the liver-to-phantom SI ratio (r = -0.88) and the subjective grading scale (rho = 0.89). Serum ferritin correlated poorly with liver iron deposition, whether assessed by biopsy (r = 0. 62) or MRI (r = -0.69). CONCLUSIONS: Both the subjective and the quantitative MRI methods proposed here are clinically valuable, with the former being adequate for a gross, the latter for an accurate estimation of tissue iron overload.

Adolescent↗
PubMed1996

Technical note: CT scout views of the cervical spine in severely head-injured patients.

The objective of this study was the validation of a CT multiprojection scout view method for the evaluation of cervical spine integrity in severely head-injured patients. Following brain CT, 130 consecutive patients underwent anteroposterior, laterolateral, and 45 degrees right and left oblique scout views of the cervical spine. The method allowed direct and prompt detection of traumatic lesions of the cervical spine in ten cases without moving the patients from the scanner table.

Adult↗
PubMed1996

Precision of sonographic measurement of articular cartilage: inter- and intraobserver analysis.

OBJECTIVE: To establish the precision of sonographic measurement of the thickness of the articular cartilage of the hip and knee in children. DESIGN: The precision was assessed by evaluating the intra- and interobserver variations in sonographic measurements. PATIENTS: A total of 65 healthy children were in the study. The articular cartilage of the right hip and knee of 40 subjects (mean age 10.3 years, range 4-16.9 years) was evaluated in masked fashion by two observers to assess the interobserver variability. The articular cartilage of the right hip and knee of 25 children (mean age 10.4 years, range 6.2-15.5 years) was examined twice by the same observer to assess the intraobserver variability. RESULTS AND CONCLUSIONS: Discrepancies between repeated measurements were expressed as data differences. The "limits of agreement" of data differences, i.e. the mean +2 SD and the mean -2 SD, ranged from -0.26 to +0.22 mm and from -0.56 to +0.48 mm for the interobserver analysis of the femoral head cartilage (FHC) and femoral condylar cartilage (FCC), respectively. The "limits of agreement" for the intraobserver analysis ranged from -0.16 to +0.15 mm and from -0.51 to +0.41 mm for the FHC and the FCC, respectively. The overall precision of the sonographic measurements was satisfactory. When used for determination of skeletal age, sonographic assessment of FHC thickness resulted in under/overestimation of skeletal age by about 7.5 months. In conclusion, sonographic measurement of articular cartilage is precise enough to be used in clinical practice.

Age Determination by Skeleton↗
PubMed1995

99mTc HM-PAO brain perfusion SPECT in brain death.

Diagnosis of brain death must be certain to allow discontinuation of artificial ventilation and organ transplantation. Brain death is present when all functions of the brain stem have irreversibly ceased. Clinical and electrophysiological criteria may be misinterpreted due to drug intoxication, hypothermia or technical artefacts. Thus, if clinical assessment is suboptimal, reliable early confirmatory tests may be required for demonstrating absence of intracranial blood flow. We have easily carried out and interpreted 99mTc HM-PAO SPECT in a consecutive series of 40 comatose patients with brain damage, without discontinuing therapy. Brain death was diagnosed in 7 patients, by recognising absence of brain perfusion, as shown by no intracranial radionuclide uptake. In patients in whom perfusion was seen on brain scans, HM-PAO SPECT improved assessment of the extent of injury, which in general was larger than suggested by CT.

Adolescent↗
PubMed1995

Spontaneous regression of exostoses: two case reports.

Exostoses are a common skeletal disorder. Despite their incidence, little is yet known about their origin and biological behaviour. In particular, spontaneous regression of exostoses--an extremely rare event--is still a subject for debate. In this study, we describe two additional cases of spontaneous regression of exostosis; one was a solitary lesion while the other occurred in a patient with multiple heritable exostoses. Radiographic findings are presented along with some of the theories which aim at explaining this phenomenon.

Bone Neoplasms↗
PubMed1994

Tc-99m HMPAO SPECT in a cerebral gunshot wound.

The authors examined regional cerebral blood flow by using Tc-99m HMPAO SPECT studies in a patient who received a gunshot wound to the brain. Although the presence of the retained bullet's fragments adversely affected the quality of CT images and contraindicated MRI studies, the SPECT examination did not have the same constraints and allowed both therapy assessment and prognostic evaluation. The repair of the cortical defect could also be assessed.

Adult↗
PubMed1993

Considerations of brain death on a SPECT cerebral perfusion study.

Brain death imaging is often a diagnostic challenge. Cerebral angioscintigraphy is extensively used for this analysis, but this test does not allow the perfusion evaluation of the posterior fossa. The authors report a case in which a SPECT study showed persistence of blood flow in infratentorial structures with total absence of cerebral (supratentorial) perfusion. This finding excluded the diagnosis of brain death.

Adult↗
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↗