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Biomedical subjects

P Pavone

Publications and source records attributed to P Pavone.

At least 19 recordsLinked to original sources
PubMed1998

Pancreatic adenocarcinoma: combination of MR imaging, MR angiography and MR cholangiopancreatography for the diagnosis and assessment of resectability.

The purpose of this study was to determine the possibility of integrating MR cholangiopancreatography (MRCP) and MR angiography (MRA) to conventional MR images in the diagnosis and assessment of resectability of pancreatic adenocarcinoma. Twenty-three patients with pancreatic adenocarcinoma were prospectively examined with MR. Conventional MR images were acquired in all patients. Three-dimensional MRCP and MRA images were acquired in all patients with suspected biliary and vascular involvement. Acquisition time was less than 45 min in all cases. Images were independently evaluated by two radiologists, with final reading decided by consensus among readers. Diagnosis was confirmed with surgery in 16 patients and with percutaneous biopsy in 7. Concordance among readers was high with a kappa value of 0.83. Pancreatic adenocarcinoma was observed in all patients. Correct assessment of unresectability due to vascular involvement was found in 22 of 23 patients. Biliary obstruction was evident in 13 patients, involving the biliary and pancreatic ducts in 9 and the biliary ducts only in 4. Technical advances permit extensive use of MRI in the evaluation of abdominal pathologies. The combination of MR imaging, MRCP, and MRA can provide sufficient information for the diagnosis and assessment of resectability of pancreatic adenocarcinoma, which otherwise would require three different exams.

Adenocarcinoma↗
PubMed1998

MR cholangiography: techniques and clinical applications.

Magnetic resonance cholangiography (MRCP) is a new non-invasive imaging technique for the evaluation of bilio-pancreatic disorders. Different sequences, using both breathhold and non-breathhold techniques, have been employed in order to obtain MRCP images. The authors discuss the technical aspects, particularly focusing their attention on a non-breathhold, three-dimensional, fat-suppressed turbo-spin-echo sequence, optimized on a 0.5-T magnet with 15 mT/m gradients. Clinical applications of MRCP are evaluated, presenting data from both the literature and personal experience. The main indication for MRCP study is represented by the evaluation of common bile duct obstruction, with the aim of assessing the presence of the obstruction (accuracy 85-100 %) and, subsequently, its level (accuracy 91-100 %) and its cause. The utility of associating conventional MR images to MRCP in malignant strictures in order to characterize and stage the malignant lesions is also discussed. Finally, data are presented regarding the indications and utility of MR pancreatography in the evaluation of patients with chronic pancreatitis.

Biliary Tract↗
PubMed1998

[Virtual endoscopy with a volumetric reconstruction technic: the technical aspects].

OBJECTIVE: We analyze the peculiar technical features of virtual endoscopy obtained with volume rendering. MATERIAL AND METHODS: Our preliminary experience is based on virtual endoscopy images from volumetric data acquired with spiral CT (Siemens, Somatom Plus 4) using acquisition protocols standardized for different anatomic areas. Images are reformatted at the CT console, to obtain 1 mm thick contiguous slices, and transferred in DICOM format to an O2 workstation (Silicon Graphics, Mountain View CA, USA) with processor speed of 180 Mhz, 256 Mbyte RAM memory and 4.1 Gbyte hard disk. The software is Vitrea 1.0 (Vital Images, Fairfield, Iowa), running on a Unix platform. Image output is obtained through the Ethernet network to a Macintosh computer and a thermic printer (Kodak 8600 XLS). RESULTS: Diagnostic quality images were obtained in all the cases. Fly-through in the airways allowed correct evaluation of the main bronchi and of the origin of segmentary bronchi. In the vascular district, both carotid strictures and abdominal aortic aneurysms were depicted, with the same accuracy as with conventional reconstruction techniques. In the colon studies, polypoid lesions were correctly depicted in all the cases, with good correlation with endoscopic and double-contrast barium enema findings. In a case of lipoma of the ascending colon, virtual endoscopy allowed to study the colon both cranially and caudally to the lesion. The simultaneous evaluation of axial CT images permitted to characterize the lesion correctly on the basis of its density values. DISCUSSION: The peculiar feature of volume rendering is the use of the whole information inside the imaging volume to reconstruct three-dimensional images; no threshold values are used and no data are lost as opposite to conventional image reconstruction techniques. The different anatomic structures are visualized modifying the reciprocal opacities, showing the structures of no interest as translucent. The modulation of different opacities is obtained modifying the shape of the opacity curve, either using pre-set curves or in a completely independent way. Other technical features of volume rendering are the perspective evaluation of the objects, color and lighting. In conclusion, volume rendering is a promising technique to elaborate three-dimensional images, offering very realistic endoscopic views. At present, the main limitation is represented by the need of powerful and high-cost workstations.

Aged↗
PubMed1997

MR cholangiography (MRC) in the evaluation of CBD stones before laparoscopic cholecystectomy.

BACKGROUND: The aim of our work was to evaluate the predictive value of MR cholangiography (MRC) in detecting CBD stones before laparoscopic surgical treatment. METHODS: MRC was performed as a unique preoperative imaging modality in 45 selected patients (16 male; 29 female; age range: 28-72; mean age: 54.4) before laparoscopic cholecystectomy. MRC imaging was obtained with a 3D Turbo Spin-Echo sequence (TR = 3000 ms, TE = 700 ms, Echo Train Length--128) with an acquisition time of 5 min 48 s. Diagnostic confirmation was obtained in all the cases at i.o. cholangiography. When a stone was detected it was removed by transcystic or transcholedochal approach. RESULTS: Eighteen of the 45 patients (40%) had CBD stones. MRC correctly evaluated 16 out of 18 stones, with a resulting sensitivity of 88.9%, specificity 100%, positive predictive value 100%, negative predictive value 90%, and accuracy 95.6%. CONCLUSIONS: Despite the good results of MRC, it cannot be proposed as a screening technique to be performed in all patients submitted to laparoscopic cholecystectomy due to high cost and the limited amount of MR equipment. In conclusion, only selected patients should be submitted to MRC before laparoscopic cholecystectomy.

Adult↗
PubMed1997

Magnetic resonance-cholangiopancreatography in the diagnosis of biliopancreatic diseases.

BACKGROUND: Magnetic resonance cholangiopancreatography (MRCP) is a new, noninvasive imaging technique for the visualization of the biliary ducts with cholangiographic images similar to those obtained with endoscopic retrograde cholangiopancreatography and percutaneous transhepatic cholangiography. No contrast medium injection is used. The aim of this study was to assess the feasibility of MRCP versus ERCP in the diagnosis of biliary tract and pancreatic diseases. PATIENTS AND METHODS: One hundred and thirty-six patients were submitted to MRCP. They were referred to MR study according to four inclusion criteria: (1) evidence or suspicion of choledocholithiasis, (2) benign or malignant bile ducts stenosis, (3) follow-up of patients submitted to biliary-enteric anastomosis, and (4) chronic pancreatitis with Wirsung duct dilatation. The MRCP was performed with a 0.5T superconducting magnet (Philips Gyroscan T5). When neoplastic disease was detected, additional images on axial planes were acquired. MRCP allowed images of diagnostic value to be obtained in all the cases. RESULTS: In choledocholithiasis, MRCP showed 91.6% sensitivity, 100% specificity, and overall diagnostic accuracy 96.8%. Of 48 patients with stenotic lesions, 16 were correctly characterized as benign and 30 as malignant. Two cases of focal chronic pancreatitis were misdiagnosed as pancreatic head carcinoma. In the patients submitted to biliary-enteric anastomosis, MCRP was able to detect the dilatation of the intrahepatic ducts, the stenosis, and associated stones in all 8 positive cases. In the remaining 7 patients with mild signs of cholangitis, MCRP showed irregular aspects of the biliary tree in the main ducts. In the 11 patients with chronic pancreatitis, MCRP was able to depict the dilated Wirsung duct and the stenotic tract, although the fine details of the secondary ducts were not evaluated due to the low spatial resolution as compared with conventional films. CONCLUSIONS: MRCP can be considered a technique able to completely replace diagnostic ERCP. Further studies are necessary for a better evaluation of the potential advantages and disadvantages of this technique.

Adult↗
PubMed1997

Role of MR venography in the evaluation of deep venous thrombosis.

PURPOSE: MR venography has been recommended for the evaluation of deep venous thrombosis. The purpose of our study was to determine the role of MR venography, in particular at the level of the pelvis where other diagnostic modalities show major limitations. MATERIALS AND METHODS: Forty-three patients with clinical suspicion of deep venous thrombosis were examined by means of pelvic MR venography. In all cases, a 2D-TOF sequence was used with cranial arterial presaturation. In selected cases, i.e. when a small intraluminal filling defect was present, a cine-PC sequence was used in addition in order to exclude the presence of a pulsatility artifact as causing the filling defect. In all cases, contrast venography was also performed and considered to be the standard of reference. RESULTS: MR venography showed 26 patients to be positive for deep venous thrombosis at the pelvic level. These positive results were correct in 25 cases. The analysis of the results provided values of sensitivity and specificity of respectively 100% and 94%, with an overall accuracy of 97.6%. CONCLUSIONS: Our results indicate that MR can provide highly accurate images, similar to those of contrast venography, in a noninvasive fashion. It is particularly useful in the pelvic region where the limitations of other imaging modalities are more evident.

Contrast Media↗
PubMed1997

MR cholangiography in the examination of patients with biliary-enteric anastomoses.

OBJECTIVE: The aim of our study was to determine the role of MR cholangiography in the noninvasive examination of patients with biliary-enteric anastomoses. SUBJECTS AND METHODS: Twenty-four patients (nine men and 15 women; mean age, 68.9 years old) with biliary-enteric anastomoses underwent MR cholangiography. We used a fat-suppressed three-dimensional turbo spin-echo sequence (3000/700 [TR/TE]; echo train length, 128) with no breath-hold, optimized with a 0.5-T magnet. Imaging studies were performed because of scheduled follow-up (five patients), persistent jaundice (six patients), cholangitis and abnormal liver function (eight patients), and a combination of transient jaundice, epigastric pain, and abnormal liver function (five patients). RESULTS: Image quality was graded from optimal to good in 21 (88%) of 24 cases and poor in three (13%) of 24 cases. The degree of bile duct dilatation was correctly assessed, with complete agreement between the two observers in all cases. MR cholangiography correctly showed bile duct irregularities in six of the eight patients with cholangitis (kappa = .59), anastomotic strictures in all 19 patients with strictures (kappa = .86), and 3- to 15-mm stones in nine of 10 patients (kappa = .95). A slight overestimation of the strictures occurred in four of the 19 cases with strictures. CONCLUSION: MR cholangiography is a reliable imaging technique for the examination of patients with biliary-enteric anastomoses.

Aged↗
PubMed1997

[Combined conventional magnetic resonance, magnetic resonance angiography, and magnetic resonance cholangiopancreatography in the diagnosis and staging of pancreatic carcinoma].

PURPOSE: This study was aimed to integrating MR CholangioPancreatography (MRCP) and MR Angiography (MRA) to conventional MR images in the diagnosis and resectability assessment of pancreatic adenocarcinoma. MATERIAL AND METHODS: Twenty-three consecutive patients with pancreatic adenocarcinoma (16 in the head and 7 in the body-tail region) were examined with MR. Conventional MR, 3D MRCP and venous and arterial MRA images were acquired to assess biliary and vascular involvement. Acquisition time never exceeded 40-45 minutes. The images were independently studied by two radiologists and the final reading was decided upon consensus among readers. Sixteen patients underwent surgery. RESULTS: The diagnosis was confirmed at surgery in 16 patients and at percutaneous biopsy in 7. Interreader agreement was considered high, with .83 interobserver variability. Pancreatic adenocarcinoma was found in all patients examined. Unresectability because of vascular involvement was correctly assessed in all patients but 1. Biliary obstruction was demonstrated in 13 patients, involving the biliary and pancreatic ducts in 9 and the biliary ducts only in 4. CONCLUSION: Technical advances now permit the extensive application of MRI to the study of abdominal conditions. The combination of MRI, MRCP and MRA can provide most of the information needed for the diagnosis and resectability assessment of pancreatic adenocarcinoma, which can otherwise be obtained only performing three different exams.

Adenocarcinoma↗
PubMed1997

[MR cholangiopancreatography: technique, indications and clinical results].

INTRODUCTION: MR cholangiopancreatography (MRCP) is a new noninvasive imaging technique for the study of biliopancreatic disorders, providing projectional images of the biliary tree and pancreatic duct without any contrast agent. MATERIAL AND METHODS: We used different sequences, with both breath-hold and nonbreath-hold techniques, to acquire MRCP images, first based on GE and then on FSE sequences. FSE images provide higher SNR and are less susceptible to artifacts (metal objects, motion and blood flow artifacts). At the Department of Radiology of the University of Rome La Sapienza, we acquired MRCP images with non breath-hold, 3D fat-suppressed TSE sequences (TR = 3000-2000, TE 700, turbo factor 128) optimized on a .5T magnet with 15 mT/m gradients. No patient preparation or sedation was required, although antiperistaltic drugs and oral administration of tap water were preferred. Four hundred and thirty patients were examined, all of them with an indication to conventional cholangiography. RESULTS: MRCP depicted the whole common bile duct and the first-order intrahepatic branches in all the normal cases. Its accuracy in identifying biliary obstruction level and site was 100%, versus 94.6% in characterizing its cause. MRCP had 96.3% diagnostic accuracy in choledocholithiasis, with some false positives and false negatives caused by: 1) small stones missed on MIP reconstructions; 2) signal loss due to complete CBD obstruction by stones; 3) pneumobilia; 4) differential diagnosis between small stones and air bubbles. The main role of MRCP in benign strictures is to provide a detailed map of the biliary tract for better treatment planning. In particular, MRCP is extremely useful in hepaticojejunostomy patients, where ERC is not indicated because of postoperative anatomical changes. Both conventional MRI and MRCP are important in malignant strictures to identify the lesion and to characterize and stage it. Finally, MR pancreatography is very useful to follow up chronic pancreatitis patients because it shows Wirsung duct strictures and dilatations, intraductal filling defects and, in some cases, the communication between the pseudocyst and the pancreatic duct. CONCLUSIONS: MRCP combined with conventional MRI can completely replace CT and ERCP in bilio-pancreatic disorders.

Adult↗
PubMed1996

MR cholangiopancreatography (MRCP) at 0.5 T: technique optimisation and preliminary results.

The aim of our study was to evaluate the feasibility of MR cholangiopancreatography (MRCP) at 0.5 T. To our knowledge no previous studies of MRCP have been performed at mid-field strength. Thirty-one patients with dilated biliary systems were examined with three-dimensional MRCP. All patients were studied with a 0.5 T superconducting magnet. A three-dimensional turbo spin-echo (TSE) sequence was acquired (TR = 5000 ms, TE = 244 ms, echo train length = 45; acquisition time = 14 min 10 s). Coronal images were post-processed with the MIP algorithm. Recently, the parameters have been optimised (TR = 3000 ms, TE = 700 ms, echo train length = 128), reducing the acquisition time to 3 min. Endoscopic retrograde cholangiopancreatography (ERCP) was performed in 26 cases; 5 patients underwent percutaneous transhepatic cholangiography PTC. MRCP and ERCP images were evaluated by an experienced radiologist and an endoscopist. MRCP of diagnostic quality was acquired in all patients. Choledocholithiasis was correctly evaluated by MRCP in 12 of 12 patients, compared with 11 correct diagnoses by ERCP. The presence and the level of the stricture were accurately shown in 16 of 16 patients with MRCP and in 13 of 16 patients with ERCP. The peripheral biliary tree above the obstruction and pancreatic duct were better evaluated by MRCP in all cases. In 3 of 3 patients who had undergone bilio-enteric surgery, a correct evaluation of the site of the anastomosis was possible with MRCP. It is concluded that MRCP performed at mid-field strength allows good visualisation of the dilated biliary system. Excellent results have been obtained on comparison with ERCP. MRCP performed at mid-field strength could have the same clinical value as high field strength MRCP.

Adult↗
PubMed1996

An integrated approach to senology education: combination of a hypermedia program with a multimedia archive.

The aim of this work was to demonstrate the computerized system on senology, which combines a hypermedia application to a multimedia didactical archive, integrated with a radiological information system. These applications have been developed on Macintosh computers using the softwares Supercard and 4th Dimension. The hypermedia application deals with basic principles of anatomy as well as the radiologic semeiology and pathology through different imaging techniques in order to illustrate basic principles. Thus, students can modify their learning pathways and the timing as they wish. Limitations are related to time consumption in preparing the programs and technical difficulties in expanding them. Multimedia archive allows to classify a large number of difficult and uncommon clinical cases, creating an easily updatable teaching file in digital format which considerably improves access to stored image data, also reducing loss of films and film degradation. From initial experiences we conclude that these systems are valid devices in information and up to date for physicians dedicated to the study of breast pathology.

Breast↗
PubMed1996

Radiology information and image management system: new approach to PACS with hypermedia capabilities of personal computers.

A system for archiving patient data and images was developed, installed, and evaluated in a radiology department. The system was developed with a relational database program for use with commercially available computers linked with an Ethernet network. The main options of the system are those of a conventional radiology information system: scheduling, registration, examination execution, reporting, archives and statistics, and system administration. However, the main feature of the system is the image archiving capability. Images are associated with patient records after capture by direct acquisition of the video signal or by scanning. Only relevant pathologic images are archived and a commonly employed compression algorithm is used, reducing the total memory requirement for each case to 200-600 kbytes. The diagnosis is still made by reading the original images. The low-resolution images stored in the system have an important role in teaching and consultation and as a first-line archive. Good results have been obtained with this system, which is used by medical and nonmedical staff without any special training.

Humans↗
PubMed1996

[Magnetic resonance pyelography: optimization of the technic and the preliminary results].

Magnetic resonance pyelography (MRP) is a new noninvasive method which demonstrates dilated urinary tracts with no need of contrast agent injection. This study was aimed at technique optimization, using new fast sequences with high intrinsic contrast, to demonstrate the urinary tract in obstructive uropathy patients. Twelve consecutive patients and 4 healthy volunteers were included in this prospective study; all the exams were performed with a high gradient power 0.5-T unit using T2- weighted turbo SE sequences, acquired three-dimensionally on the coronal plane. Obstructive uropathy was caused in 9 patients by neoplastic lesions, in 2 by postoperative strictures and in 1 by inflammatory tissue. In all patients MRP depicted the dilated urinary tract optimally, with good morphological detailing and the accurate assessment of both level and cause of obstruction. In the healthy volunteers, the absence of dilatation did not permit the complete visualization of the urinary tract. To conclude, MRP is a new technique which permits high-quality imaging of the urinary tract. Further studies are needed to assess its actual potentials and clinical role.

Adult↗
PubMed1996

[Lithiasis of the common bile duct: the role of cholangiography and magnetic resonance].

The aim of our study was to evaluate the sensitivity, specificity and diagnostic accuracy of Magnetic Resonance Cholangiography (MR-CP) in patients with suspected choledocholithiasis. Sixty-two patients (mean age: 56.3 years) previously submitted to US, were examined with MRCP. MR exams were performed with an 0.5 T superconductive magnet (Gyroscan T5-II; Philips, Medical System, Best, NL) and a body coil. 3D-TSE sequences (TR/TE/ETL = 5.000/244/45 ms) were acquired, with 14 min 10 sec acquisition time. In the last 21 patients, acquisition time was reduced down to 3 min, by optimizing the parameters as follows: TR/TE/ETL = 3.000/700/128 ms. The images, obtained on the coronal plane, were then reconstructed with the MIP algorithm. MRCP images were studied both as MIP reconstructions and as single slices. The diagnosis was always compared with endoscopic or percutaneous findings. MRCP images were of diagnostic quality in all cases, with 91.7% sensitivity, 100% specificity and 96.8% diagnostic accuracy. MRCP had 100% positive predictive value and 95% negative predictive value. In conclusion, this technique is extremely useful to examine the patients with obstructive jaundice secondary to lithiasis.

Adult↗