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Biomedical subjects

M Bonetti

Publications and source records attributed to M Bonetti.

36 records · Page 2Linked to original sources
PubMed1994

[Subarachnoid hemorrhage: assessment in the acute phase with angiography, with high-resolution magnetic resonance (angio-MR)].

Previous reports demonstrated that Magnetic Resonance Angiography (MRA) is a reliable means of diagnosing intracerebral aneurysms. However, in these early studies MRA was performed in patients with cerebral aneurysms already proved by intraarterial angiography. Our study was aimed at investigating the clinical feasibility and the diagnostic accuracy of high-resolution MRA in patients with acute subarachnoid hemorrhage. Twenty-five patients (15 women, 10 men) with CT diagnosis of subarachnoid hemorrhage were prospectively examined with high-resolution MRA within 24 hours of bleeding. All patients underwent intraarterial digital subtraction angiography (IA DSA) immediately after MRA examination. MRA studies were performed with a 1.5-T unit. MRA examinations of the cerebral vessels consisted of axial excitation of two 50-mm volume slabs, with 25% overlap, covering the cerebral circulation from the vertebro-basilar junction to the pericallosal artery. Pulse sequence variables were optimized to reduce voxel size (0.62 x 0.62 x 0.78) and to increase spatial resolution (160-mm FOV, 256 x 256 matrix, 0.78-mm slice thickness) while keeping S/N ratio high. The maximum intensity projection (MIP) reconstruction algorithm was used. The examination lasted nearly 20 minutes. Four MRA examinations (16%) were considered inadequate for diagnosis because of motion artifacts. High-resolution MRA detected 20 of 21 aneurysms in 17 patients, with 1 false positive and 1 false negative. Two patients had multiple aneurysms, 2 and 4 respectively, all of them detected by MRA. No cause of subarachnoid hemorrhage was found by IA DSA in 4 patients, while MRA studies were considered negative in 3 patients. Nineteen aneurysms were surgically clipped, while 2 basilar artery aneurysms were occluded by intravascular treatment. MRA and DSA findings were compared with surgical findings. Relative to IA DSA, MRA exhibited 95% sensitivity and 95% specificity. Aneurysm size ranged 2-10 mm: the smallest aneurysm detected by MRA was 2.5 mm. Anatomical and morphological agreement between MRA and IA DSA was excellent, with only slight MRA underestimation of the aneurysm size in 25% of cases and overestimation in 15% of cases. The aneurysm neck was shown by MRA in 60% and by IA DSA in 81% of cases. High-resolution MRA proved to be especially useful in complex anatomical sites where the direction of the aneurysm could be clearly demonstrated through the accurate selection of the appropriate projection angle and the careful examination of direct axial images.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗
PubMed1993

Hepatic tumor and tumor-like lesions in childhood.

Tumors of the liver are rare in infancy and childhood. Some are peculiar to the pediatric age, e.g., hepatoblastoma, infantile hemangioendothelioma, mesenchymal hamartoma, embryonal rhabdomyosarcoma. This review is based upon personal experience with a series of 32 cases. On the basis of the histological features it is proposed that focal modular hyperplasia (FNH) and mesenchymal hamartoma be considered as tumor-like lesions rather than true neoplasms. A few benign epithelial lesions (FNH, adenoma) were associated with inborn error of metabolism. In half of the patients, hepatocellular carcinoma (HCC) developed in perinatally hepatitis B virus (HBV)-infected children. HCC developed in a noncirrhotic liver in a single patient, in whom HBV-DNA integration had occurred.

Carcinoma, Hepatocellular↗
PubMed1987

Oral anticoagulant therapy control: evidence that INR expression improves the inter-laboratory comparability of results--the Bologna oral anticoagulant control exercise.

The aims of the present study were: 1) interlaboratory normalization of prothrombin time (PT) testing for anticoagulant therapy control through calibration of customary thromboplastins against international reference materials, and 2) "on field" validation of the advantages offered by expression of results as International Normalized Ratio (INR) as opposed to percentage activity. PT tests were carried out over 8 days on the same normal subjects (16) and patients on oral anticoagulants (48) in the 9 laboratories of the Bologna area. The use of customary thromboplastins and coagulometers was maintained in all labs throughout the study. The main results were: 1) the interlaboratory CV of the prothrombin ratios obtained for each sample with all customary thromboplastins (5 different brands) was 15%, but was reduced to levels of 5.8 to 8.9 when using constant thromboplastin brands and batches; 2) the International Sensitivity Index (ISI) values obtained in the different labs were only slightly influenced by the use of different coagulometers; 3) comparable ISI values were obtained through direct calibration with the international reference material and through intermediate calibration with a locally selected standard; 4) use of INR values instead of percentage activity greatly reduced interlaboratory variability and significantly improved uniformity of anticoagulation level measurements, thus reducing the possibility of erroneous prescriptions. The Bologna exercise is therefore of educational value for laboratory and community doctors of the area in understanding and accepting the INR system.

Administration, Oral↗
PubMed1985

A simple method of predicting left ventricular function in stabilized chronic respiratory failure.

A simple method of assessing left ventricular function in stabilized chronic respiratory failure (CRF) is proposed. 21 patients with CRF were ranked according to the prediction of left ventricular function derived from eight elementary clinical criteria including standard chest X-ray and conventional basal electrocardiography. Equilibrium radionuclide angiocardiography was performed at rest (rERNA) for the evaluation of left ventricular systolic function (ejection fraction, LVEF; peak ejection rate) and diastolic function (peak filling rate). Right ventricular ejection fraction (RVEF) was also measured. The clinical evaluation of the left ventricular function showed a high correlation with rERNA data (p less than 0.01 by Spearman's rank test). No correlation was found between rERNA parameters and PaO2 and between RVEF and LVEF. The clinical criteria proposed can thus predict left ventricular function in stabilized CRF with a high degree of confidence.

Angiocardiography↗
PubMedDate not supplied

[Role of cerebral magnetic resonance angiography in childhood].

This study evaluates the role of cerebral MR Angiography (MRA), as a part of the flowchart for the assessment of the brain in childhood. This noninvasive technique provides intra- and extra-cranial anatomic and physiologic vascular information, with a level of precision almost equal to that of arterial angiography. Indeed, MRA has reached a level of diagnostic accuracy such that the need for arterial angiography can be avoided, in most cases of cerebrovascular disorder. Therefore arterial angiography could be performed at the subacute (and more neurologically stable) stage, or presurgically, yielding additional morphologic and hemodynamic insights into cerebrovascular disease. MRA is also indicated at follow-up examination, and in treatment planning.

Brain↗
PubMedDate not supplied

[Magnetic resonance myelography. Preliminary experience].

Three-dimensional (3D) MR Myelography is a new technique using constructive interference steady-state (CISS) sequences, which are characterized by a symmetric flow compensation enhancing CSF signal intensity compared with neural and extradural structures. 3D myelographic projections with different rotation angles are obtained from the 3D dataset with a mathematical algorithm called maximum intensity projection (MIP). Myelographic projections yield a global view of subarachnoid spaces and of root sleeves with no intrathecal contrast agent injection. This study was aimed at assessing the feasibility, the clinical value and the diagnostic accuracy of 3D MR Myelography in comparison with conventional myelography. From September 1992 to January 1994, thirty-five myelograms were performed. The study population consisted of 10 volunteers, 8 patients with traumatic brachial plexus lesions, 7 with herniated disks (4 lumbar and 3 cervical disks), 4 with sacral radicular cysts, 2 with spinal vascular malformations, 3 with extramedullary intradural neoplasms (2 cervical neuromas and 1 cervical meningioma) and 1 with an intramedullary tumor (a conus medullaris ependymoma). All patients underwent SE MRI and conventional myelography (22 lumbar injections, 3 cervical injections of nonionic iodinated contrast agent) followed by CT (CT myelography). This trial demonstrates the feasibility of 3D MR myelography in the study of the cervical and lumbar spine: its results are comparable to those obtained with conventional myelography also in some specific indications like traumatic brachial plexus injuries, where invasive conventional myelography is usually thought to be essential.

Algorithms↗
PubMedDate not supplied

[The role of 3D CT in the treatment of maxillofacial malformations].

The computed tomographic studies obtained routinely in the examination of patients with congenital defects of facial bones can be utilized as a substrate to provide an accurate three-dimensional representation of osseous abnormalities. It is a useful tool for the maxillo-facial surgeon in clinical application, in diagnosis, accurate measurements, preoperative planning and post-operative follow-up. The experience of the Division of Maxillo-Facial Surgery of Bellaria Hospital and of the Radiological Department of Instituto Rizzoli at Bologna is presented.

Adolescent↗