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Biomedical subjects

P Pavone

Publications and source records attributed to P Pavone.

At least 163 records · Page 9Linked to original sources
PubMed1990

[Staging of bronchogenic cancer. Determination of mediastinal lymphatic involvement using magnetic resonance].

Twenty-five patients with bronchogenic carcinoma were prospectively studied by both CT and MR during 10 days preceding thoracotomy. MR scans included contiguous axial and coronal slices. Results of CT and MR studies were compared with the surgical and pathological findings. Although no significant difference was found between the two imaging methods for the evaluation of mediastinal nodes. MR appear to be superior to CT in the aortopulmonary and subcarinal node areas.

Adult↗
PubMed1990

[An animal model for the study of liver regeneration by magnetic resonance imaging].

Liver regeneration after partial hepatectomy was studied in rats by means of magnetic resonance (MR) imaging and T1 relaxation time. Fourteen hepatectomized rats were compared to sham operated ones and to controls which had not undergone any surgical treatment. The animals were imaged at 0.5 T, and inversion recovery (IR) technique was employed at the T-null of liver before surgery. T1 was determined in vitro with spectroscopy. Regenerating rat liver exhibited a significantly high increase in MR signal intensity and T1 values (p less than 0.05) 24 hours after surgery, returning to baseline values at 2 weeks. Sham operated animals and controls did not exhibit significant changes in signal intensity from baseline values (p greater than 0.05). These findings suggest that MR imaging is able to detect the pathophysiological changes occurring in liver parenchyma during the regenerating process and to monitor different stages of the hyperplastic process.

Animals↗
PubMed1990

[A comparative study between Gd-BOPTA, a biliary excretion contrast medium, and Gd-DTPA in the magnetic resonance imaging of the rat liver].

A new lipophilic compound, Gd-BOPTA, presenting a high rate (38.6%) of biliary excretion was tested as an hepato-specific MR contrast agent. Its adequacy was compared to that of Gd-DTPA in laboratory animals. T1-weighted spin-echo sequences (TR 220 ms, TE 20 ms) both before and after the administration of the 2 contrast agents (doses: 0.25, 0.5, and 1.0 mmol/kg) showed better liver enhancement with Gd-BOPTA than with Gd-DTPA. Gd-BOPTA superiority was more evident at lower doses, while at 1.0 mmol/kg a comparable enhancement was achieved. Inversion recovery sequence at the T-null of liver parenchyma before contrast (TR 800 ms, TE 30 ms, TI 100 ms) was performed after the injection of 0.1 and 0.5 mmol/kg of Gd-DTPA and Gd-BOPTA. This sequence allowed the good and long-lasting liver enhancement achieved with Gd-BOPTA to be even better demonstrated, while Gd-DTPA provided only a slight and early enhancement with 0.1 mmol/kg and returned to baseline values 60' after the injection of the highest dose (0.5 mmol/kg). Gd-BOPTA proved to be a good contrast agent to obtain prolonged liver enhancement, thus providing the radiologist with the long time needed to acquire conventional T1-weighted pulse sequences.

Acetates↗
PubMed1990

[Pathologic dilatation of the thoracic aorta: a study using magnetic resonance].

Magnetic resonance (MR) imaging provides detailed evaluation of cardiovascular structures, due to high intrinsic contrast between flowing blood and vessel's lumen. Early application have shown the clinical validity of the technique, with non-invasive, multiplanar imaging of large and medium sized vessels. In this study we evaluate the capabilities of MR in screening out patients with thoracic aorta enlargement. Examination has been performed in 16 patients, employing a 0.5 T superconductive unit, and acquiring images on axial, sagittal and coronal planes with 7 mm slice thickness. In 15 cases it was possible to detect the pathology and to characterize it according to type, location and extension. In 1 case it was no possible to make an accurate diagnosis for the presence of movement artefacts, due to poor patient's cooperation. In dissecting aneurysms the true and false lumen may be differentiated, with a good visualization of the intimal flap. The relation between the origin of the aortic branches and the aneurysm may also be ascertained.

Adult↗
PubMed1989

Thrombolysis of graft occlusion using high dose urokinase. An alternative to surgical treatment?

Two cases of acute leg ischemia from unilateral occlusion of an aorto-bifemoral graft, treated with high-dose urokinase intra-arterial infusion, are reported. This therapy allowed identification of the cause of thrombosis, recanalization of the graft and planning of reoperation. Indications for intra-arterial thrombolytic therapy and advantages of urokinase vs streptokinase are discussed.

Aged↗
PubMed1989

Magnetic resonance imaging of abdominal aortic grafts.

The widespread use of abdominal aortic grafting procedures and increasing awareness of related complications suggests the need for a reliable and non-invasive diagnostic technique which will allow early detection of both occlusive and non-occlusive complications. Ultrasound is generally used with satisfactory results, but has several limitations, whereas MRI has shown great promise in the study of cardiovascular disease, being non-invasive, multiplanar and multiparametric. The present research aims to evaluate MRI in the follow-up of abdominal aortic grafts, attempting to define its significance as a screening procedure in non-selected patients. MRI is reliable in ascertaining the normality of the graft as well as the complications, these being partial or total thrombosis, pseudoaneurysms and perigraft collections. The data obtained are highly satisfactory and are almost always superior to those achieved with ultrasound and CT.

Aorta, Abdominal↗
PubMed1989

[Optimization of the technic in the study of the upper abdomen using magnetic resonance. I. Artifact reduction].

Complete motion artifact suppression is possible in abdominal MR imaging with the simple optimization of sequence parameters, with no need for special softwares. The authors have studied the influence of sequence parameters modification on the signal/noise relation and on the presence of motion artifacts. The tested parameters included Repetition Time (TR), 150 to 2000 ms, Echo Time (TE), 20 to 120 ms, and the number of acquisitions, 2 to 16. In T1-weighted sequences, the major advantages were offered by the short TR and short TE association, with many acquisitions. Optimal signal/noise relation and complete motion artifact suppression were thus obtained. In T2-weighted sequences, TE values had to be changed according to the desired contrast enhancement, and the number of acquisitions could not be increased to more than 2 in order to keep the acquisition time short.

Abdomen↗
PubMed1989

[Magnetic resonance in the characterization of atherosclerotic lesions].

Fifty-one patients with occlusive and dilating vascular diseases were evaluated with MR imaging, using T1 and T2-weighted sequences and an 0.5 T superconducting magnet. Atheromatous plaques were detected in the carotids and on the aortic walls. Fatty lesions had high signal intensity on T1-weighted sequences and could be well distinguished from older thrombotic depositions which presented with medium signal intensity on T1-weighted scans and low signal on T2-weighted images. Thrombotic depositions in aneurysmal dilatation of the aorta and carotid arteries could be distinguished from patent internal lumen; inside them, areas of different signal intensity were demonstrated, which were related to the paramagnetic effect of hemoglobin degradation products (hemosiderin and methemoglobin).

Aorta, Abdominal↗
PubMed1988

[Abdominal aortic aneurysms. Comparison of magnetic resonance, ultrasound, CT x-ray and angiography].

Twenty-four cases of abdominal aortic aneurysm were studied by means of MR Imaging, Computed Tomography (CT), Ultrasound (US) and Angiography. MR Imaging gave detailed information on the site and extension of the aneurysm. The extent of branches involvement, the presence of thrombosis, and the adjacent structures were also demonstrated. Major limitations of angiography were its morbility, and the difficult/impossible demonstration of eventual thrombi, and of the adjacent structures. CT, although extremely valuable in emergency cases and in the detection of calcifications, provided insufficient information on the involvement of the vessels originating from the aorta. US proved useful in the screening of abdominal aortic aneurysms, but lacked both the accuracy and the reliability necessary to a complete preoperative evaluation. MR Imaging proves thus to be a good investigation technique for a complete assessment of aneurysmatic lesions. Its major limitation is its inability to detect calcifications, while its major advantages are the accurate demonstration of both blood flow and eventual thrombi, and the multiplanarity and non-invasiveness of the methodology.

Aged↗
PubMed1988

[Clinical evaluation of biliary endoprostheses. A comparison of endoprostheses made of teflon and percuflex].

For the decompression of the biliary tree in case of obstructive neoplastic jaundice, 62 biliary endoprostheses were placed in 54 patients as an alternative to internal-external drainage. Teflon prostheses were used in 26 patients--which were placed in the stenotic tract--while in 28 patients soft percuflex prostheses were used, whose lower extremity was placed in the duodenum. The mean survival has been 6-7 months, with peaks ranging from 1 month to 2 years. By comparing the results obtained with the two different kinds of prosthesis we found that soft endoprostheses were associated with a lower incidence of late complications than teflon prostheses: cholangitis occurred in 7.2% of cases (vs teflon: 16%), occlusions in 3.5% (vs teflon: 11.5%), migrations in 7.2% (vs teflon: 7.6%). The incidence of such complications was, however, higher a few months after the application of the prosthesis. This palliative treatment is suggested in patients whose expected survival is not longer than 1-6 months. On the contrary, in case of patients with a better prognosis, an internal-external catheter drainage is preferred, for an easier access to the site of the lesion.

Adult↗
PubMed1988

Multiple imaging modalities in a case of hibernoma.

Hibernoma is a rare hypervascular benign tumour that originate from brown fat. A case of hibernoma of the thigh, examined by xeroradiography, ultrasound, CT and angiography, is reported. The characteristics of this tumour are considered.

Adipose Tissue, Brown↗
PubMed1988

Iopamidol 150 in intra-arterial digital angiography of the peripheral vasculature: a comparative study.

The results of a comparative double-blind clinical trial involving peripheral intra-arterial DSA performed with low iodine iopamidol concentrations (150 and 200 mg. I/ml.) are reported. Forty-six patients were examined for vital signs, local (heat and pain sensations) and systemic reactions and monitored throughout the procedure. No untoward effect was observed apart from mild local reactions, which on the other hand did not produce any movement artifacts. Image quality was good to optimal in 98% of the cases. In no case were higher concentrations of contrast medium (cm) needed. No significant differences between the two concentrations of cm used were observed with respect to either contrast ability or tolerability.

Angiography↗
PubMed1988

[Magnetic resonance in the evaluation of intracranial aneurysms].

Eighteen patients affected by intra-cranial aneurysms, with size ranging from 3 to 30 mm, were studied by means of MRI, CT, and angiography. MRI was performed using Spin-Echo (SE) sequences with different Repetition Times (TR) and Echo Times (TE), which allowed the characterization of the lesions in relation to the relaxation times. MRI could identify all the aneurysms. In 13 subjects the parent vessels could be seen. In 5 patients the aneurysms could be recognized only after angiography, due to their dimension (less than 4 mm). The "flow effects" and the presence of methemoglobin and hemosiderin in the thrombosed portion of the lumen allowed both the detection of flow abnormalities and the characterization of laminate intra-aneurysmal thrombosis. In conclusion, MRI appears to be a sensitive methodology in the detection of intracranial aneurysms, even more sensitive than CT and Angiography in characterizing this kind of lesions.

Adult↗