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Biomedical subjects

P Pavone

Publications and source records attributed to P Pavone.

At least 127 records · Page 7Linked to original sources
PubMed1994

[The MR tomography of focal liver lesions with the superparamagnetic contrast agent AMI-25 at 1.5 tesla].

Superparamagnetic iron oxide particles (AMI-25) were evaluated as a liver contrast agent in high-field MR imaging (1.5 T). 16 patients with up to 5 presumed focal liver lesions (liver metastases n = 8, HCC n = 5, Klatskin tumours n = 2, FNH n = 1) received 15 mumol Fe/kg BW intravenously and were examined via standard T1- and T2-weighted spin-echo sequences. Quantitative image analysis showed a post-contrast increase of the contrast-to-noise ratio (C/N) from 1.6 to 7.4 on SE 2,500/15 images (p < .05). However, C/N was in the same range on plain SE 2,500/90 scans. Blind evaluation by two independent readers revealed that AMI-25-enhanced images did not provide a significantly increased number of lesions. Two patients reported minor, self-limited side-effects (flush, back pain). We conclude that in contrast to reports at mid-field MR imagers, the use of AMI-25 at 1.5 T does not significantly improve the detection of focal liver lesions on conventional SE images.

Adult↗
PubMed1994

[The role of intraoperative echography in laparoscopic cholecystectomy].

On the basis of recent technological improvements, the laparoscopic approach has become the method of choice during cholecystectomy. This surgical procedure, however, needs that cholangiography be performed simultaneously to better define the anatomy of the biliary ducts and the possible presence of choledochus stones. The use of intraoperative US during cholecystectomy is nowadays advocated for the unquestionable advantages offered by this technique--i.e., its non-invasiveness, high spatial resolution and no need of contrast agent administration. In this study, we examined 30 patients with cholelithiasis who underwent laparoscopic cholecystectomy and were submitted to endolaparoscopic US besides routine intraoperative cholangiography. In all cases, both techniques allowed optimal visualization of the biliary tree, clearly demonstrating choledochus stones in 2 cases. Intraoperative US proved to be more accurate in two cases. In one case which was positive at intraoperative cholangiography, the method allowed the biliary duct filling defect to be referred to an artifact caused by the presence of an air bubble. In another case, the lack of opacification of the hepatic ducts at cholangiography was referred, after US, to extrinsic gallbladder compression. US also allowed the adjacent parenchymal organs, such as the liver and the head of pancreas, to be studied. A limitation of this technique was represented by the difficult assessment of the choledochus in the patients with anatomical abnormalities or adhesions of the intestinal loops of the upper abdomen. In conclusion, endolaparoscopic US proved to be a reliable technique in the intraoperative study of the biliary ducts and can be considered as a procedure complementary to intraoperative cholangiography.

Biliary Tract↗
PubMed1994

[Intraoperative digital cholangiography during laparoscopic cholecystectomy interventions].

In the last years, laparoscopic cholecystectomy has become the method of choice in the surgical treatment of gallbladder stones. Recently, the same laparoscopic approach has been used to remove choledochus stones. This surgical procedure needs the accurate intraoperative study of the biliary tree with diagnostic imaging modalities to better define the anatomy of the biliary ducts and the possible presence of choledochus stones. To this purpose, transcutaneous and endolaparoscopic US with dedicated probes and intraoperative cholangiography can be performed. In this study, we performed 30 laparoscopic cholecystectomies during which all the patients were submitted to intraoperative cholangiography with a digital fluoroscopic unit. The maneuvers for catheter insertion in the cystic duct and the examination as a whole took 3 to 5 minutes. Intraoperative cholangiography demonstrated choledochus stones in 3 patients, while preoperative US detected them in 2 patients only. In 8 cases the dynamic study, carried out with digital image acquisition, allowed to refer the biliary duct filling defects to artifacts caused by the presence of air bubbles. In conclusion, intraoperative cholangiography, also during endolaparoscopic cholecystectomy, plays a major role in the surgical assessment of the biliary tree. When the procedure was performed with a digital fluoroscopic unit, its diagnostic accuracy was higher and the images on the TV monitor were better visualized.

Cholangiography↗
PubMed1993

Role of magnetic resonance imaging (MRI) in detecting liver changes after gallstone extracorporeal shock wave lithotripsy (ESWL).

Recently published literature on biliary extracorporeal shock wave lithotripsy (ESWL) has shown that high-energy ESWL utilizing high kV is more effective than the low-energy ESWL and low kV used previously. Prior studies have not reported injury to the gallbladder or adjacent liver following ESWL. Our study evaluated 29 patients that were treated with high kV ESWL. Magnetic resonance imaging (MRI) was used to study the gallbladder and adjacent liver for possible injury resulting from the high-energy treatment. The patients, selected using the Dornier MPL-9000 United States protocol, underwent ESWL using 18-24 kV (average 21 kV). MRI was done both pre and post-ESWL in all 29 patients. Ten patients had a second treatment to reduce fragment size and, subsequently, had an additional MRI examination. Spin echo MRI images were obtained at the level of the gallbladder fossa using a 0.5-Tesla ESATOM RM 5000 (ESAOTE Biomedica, Genva, Italy.) superconductive unit. Both T1- and T2-weighted images were obtained. In 26 patients the hepatic parenchyma was normal post-ESWL. Two patients had a hyperintense region on T1-weighted images post-ESWL that was felt to be related to pericholecystic fat. A third patient had an abnormality detected on T2-weighted images that was thought to be due to hepatic edema or microhemorrhage. No significant changes were shown by laboratory or concurrent ultrasound examinations. Repeat MRI examinations in these three patients were normal. High-energy ESWL appears as safe as low-energy ESWL in the treatment of patients with symptomatic gallstones.

Adult↗
PubMed1993

[Hypermedia software for teaching anatomy of the upper abdomen with computerized tomography and magnetic resonance].

The authors have developed a hypermedia program for creating a tutorial of CT and MR anatomy of the upper abdomen. The program was created on a Mcintosh computer, with the Supercard software: it is made up of a series of windows, each of them containing images, texts, schematic representations and sound. Moreover, each window contains buttons which are activated with the mouse and allow different kinds of function, all created by the authors to be displayed. In particular, navigation buttons allow the users to move in the program either sequentially or non-linearly, according to their needs. The possibility of obtaining information and schematic representations is given by specific buttons. There are also multiple buttons hidden in the images which, when activated, allow the name of the selected organ to be displayed. In conclusion, this program can be especially helpful since it allows different data sets to be integrated to provide the user with complete information. Moreover, the program allows learning to be controlled, that is the user to be informed on timing and methods for more effective studying.

Abdomen↗
PubMed1993

[Angiography with magnetic resonance of the ++carotid arteries. Evaluation of clinical results obtained with low magnetic field equipment].

Magnetic Resonance Angiography (MRA) is the latest diagnostic technique for the noninvasive evaluation of cardiovascular conditions. This technique has proved to be especially useful in the study of carotid arteries. All the clinical studies reported to date have been obtained at high or medium field strength; our purpose is to assess the clinical value of MRA in the evaluation of carotid arteries at low field strength. All the exams were performed with an 0.2 T permanent magnet, using the 2D time of flight (TOF) technique, the only one which is currently available on our equipment. Forty-two patients with clinical diagnosis of cerebrovascular insufficiency were examined. In all cases MRA findings were confirmed with digital subtraction angiography (DSA), which was considered the gold standard. The double-blind evaluation of the results showed high agreement of the two techniques in 70 of 84 carotid arteries. A mild tendency to overestimation was observed in 4 normal cases considered as mild stenoses on MRA, in 2 cases with mild stenosis considered as discrete stenoses on MRA and in 1 case of severe stenosis considered as an occlusion on MRA. Underestimation was seen in 1 case of mild stenosis considered as normal on MRA, in 2 cases of discrete stenosis which appeared as mild stenoses on MRA and in 2 cases of occlusion considered as severe stenoses. Our study showed high agreement between MRA and DSA results, which means that high quality exams can be obtained even at low field strength. Further progress can be expected when 3D TOF and phase-contrast techniques will be introduced.

Adult↗
PubMed1993

[Animal experimentation in radiology. Objectives, organizational and ethical problems].

The contribution of biomedical sciences to the scientific breakthroughs in the last years has benefitted also by experiments on animals. As for diagnostic imaging, the use of new contrast media for angiography, CT and MRI makes it necessary, according to the law, to perform preliminary animal studies to test efficacy, pharmacokinetics and pharmacodynamics of the contrast agents. Experimental animal studies of clinically well-established contrast agents are also justified by the need to implement new imaging modalities. The close relationship between medical research and animal experimentation has awakened public opinion, as well as the researchers themselves, to the ethical and legal problems related to animal testing. This paper reports on the regulations which are currently in use in this field.

Animals↗
PubMed1993

Magnetic resonance angiography: current clinical applications.

Magnetic Resonance Angiography (MRA) is the newest non-invasive procedure for the evaluation of the vascular system. The basis to obtain images of vessels from Magnetic Resonance (MR) data rely upon the specific signal alteration determined by flowing blood. By using special techniques only these signals are evidenced, with cancelling of the surrounding stationary tissues. Clinical applications are reviewed in this paper. They include: Evaluation of intracranial vessels with important adjunct information to those obtained by conventional MR images; Definition of cerebrovascular disease including the carotid artery with good correlation with Digital Subtraction Angiography (DSA); Evidence of abdominal vessels, with clear imaging of abdominal aortic aneurysms; Definition of renal arteries; although problems exist, the technique may become useful in the future for the screening of renovascular hypertension; Visualization of peripheral vessels; initial results indicate a potential application in the evaluation of peripheral run-off distal to occlusions.

Carotid Artery Diseases↗
PubMed1992

A rare cause of digestive hemorrhage: an aneurysm of the superior pancreaticoduodenal artery rupturing into the duodenal stump of a Billroth II partial gastrectomy.

We report herein a case of an iatrogenic superior pancreaticoduodenal arterial aneurysm which ruptured into the duodenal stump of a Billroth II partial gastrectomy. Superselective angiography was used for the diagnosis, and successful embolization performed nonoperatively. A review of the literature revealed both the etiology and site of rupture in this case to be extremely uncommon.

Aneurysm↗
PubMed1992

Identification of coronary artery by-pass grafts: reliability of MRI in clinical practice.

In order to test MRI ability to detect the number and the sites of coronary artery by-pass grafts (CABGs), 22 patients with CABGs were studied. The detection of a neo-vessel in even one of the examination slices was considered as positive for the study, disregarding the difference between its origin and course. With such a criterion, MRI total percentage of vascular bridges identification resulted in 76.1% (51/67) with very low values for CABGs implanted on diagonal, obtuse marginal and posterior descending vessels (11/24 = 45.8%). These results lead to the conclusion that, although MRI has some advantages in the identification of CABGs implanted on the main coronary vessels in the early post-operative period, its extensive use cannot be proposed at the present state of the art.

Adult↗