Biomedical subjects
Publications and source records attributed to P Pavone.
We report on two infants with primary unilateral thalamic hemorrhage which occurred at two months of age. Both infants were normal prior to the onset of hemorrhage. Both children presented with seizures and subsequently developed epilepsy. These cases suggest that primary unilateral thalamic hemorrhage can occur in seemingly well infants outside the neonatal period.
Recently, there has been increasing interest in the study, characterization, and management of infantile spasms. With technological advances, it is now possible to determine a specific diagnosis on many patients with infantile spasms, thus broadening the spectrum of conditions associated with this electroclinical syndrome. We report a child with infantile spasms who also had a vascular malformation of the vein of Galen. Both clinical and electroencephalographic findings improved rapidly after endovascular treatment of the vascular anomaly, suggesting a possible association.
We report a 10-year-old girl with Marin-Amat syndrome, a rare facial synkinesis sometimes referred to as the inverted Marcus Gunn phenomenon. Symptoms were apparent 6 months following unilateral peripheral facial nerve palsy. Her facial synkinesis failed to improve, despite improvement in her facial palsy consistent with an aberrant regeneration of the facial nerve. The clinical Several neurologic syndromes feature abnormal interactions, or synkinesis, between anatomically proximate muscle groups. Among these, the Marcus Gunn phenomenon (trigemino-oculomotor synkinesis) is one of the best described in children. The Marcus Gunn phenomenon, or 'jaw-winking phenomenon,' consists of unilateral congenital ptosis and retraction of the ptotic lid upon moving of the lower jaw. Although many adults have been reported with this synkinesis, it is usually most prominent in newborn infants, in whom rapid spasmodic movements of the lid are seen during periods of nursing. In general, the Marcus Gunn phenomenon is unilateral and sporadic although familial and bilateral cases have been reported. Marin-Amat syndrome (or 'inverse Marcus Gunn phenomenon') is a rarely reported synkinesis in which one eyelid closes upon full opening of the jaw or movement of the jaw laterally. We now report a 10-year-old patient who began to develop features of Marin-Amat syndrome involving the right eyelid 1 month following right facial nerve palsy. This is the first documented report of this syndrome in a child.
OBJECTIVE: The aim of our study was to assess the role of MR cholangiography in the diagnosis of late biliary complications after liver transplantation. SUBJECTS AND METHODS: Twenty-three liver transplantation patients (18 men and five women; mean age, 46 years) underwent MR cholangiography using a nonbreath-hold, fat-suppressed three-dimensional turbo spin-echo sequence (TR/TE, 3000/700; echo train length, 128) optimized on a 0.5-T magnet. Inclusion criteria were liver function tests with abnormal results and hyperbilirubinemia with a clinical pattern not specific for biliary obstruction. All patients were referred by clinicians for contrast-enhanced cholangiography. Diagnostic confirmation was obtained with percutaneous transhepatic cholangiography (n = 4), endoscopic retrograde cholangiography (n = 8), T-tube cholangiography (n = 1), or clinical follow-up (n = 10). RESULTS: In 11 patients, no abnormalities of the biliary tract were revealed by MR cholangiography. In 11 patients, twelve strictures were diagnosed (nine anastomotic, two nonanastomotic-intrahepatic, and one nonanastomotic-extrahepatic, with association between anastomotic and nonanastomotic strictures in two cases). In one other patient, kinking of the common bile duct at the level of the anastomosis was observed. In all cases, MR cholangiography correctly showed the site of the stricture and the dilatation of bile ducts above, with excellent correlation with contrast-enhanced cholangiographic findings. Strictures were correctly graded in eight of 10 patients and were overestimated in two. Other findings included a 1-cm stone detected proximal to the obstructed common bile duct in one patient and multiple intrahepatic stones in another patient. CONCLUSION: MR cholangiography can show biliary obstruction and provide important information for planning therapeutic procedures.
OBJECTIVE: To determine the role of MR imaging in the localization of pancreatic insulinomas in patients with clinical and laboratory diagnosis of insulin-producing tumor. MATERIAL AND METHODS: Thirty-one patients presenting with signs and symptoms of pancreatic insulinomas were prospectively included in our study. Twenty-six patients underwent surgery, and pathologic specimens were examined: 5 patients, in whom the initial diagnosis of insulinoma was excluded, were also studied and then followed up. All patients were studied with a high gradient power 0.5 T magnet. Images were evaluated by 2 radiologists blinded to previous investigations, tests and results. RESULTS: MR imaging correctly localized 24 of the 26 insulinomas (2 were false-negative and 1 false-positive) and was correctly negative in the 5 control patients. The interobserver agreement had a kappa value of 0.89. CONCLUSION: MR imaging was accurate in localizing pancreatic insulinomas and as a consequence, patients in our institution are now submitted to surgery directly after the MR examination. Invasive methods are considered only in cases in which, despite clear biochemical results, MR imaging has not demonstrated a pancreatic focal lesion.
PURPOSE: To evaluate the possible role of MR imaging in the assessment of patients with urinary tract obstruction by combining conventional MR imaging and MR pyelography (MRP). MATERIAL AND METHODS: Forty-three patients with dilated upper urinary tract were studied with a high gradient strength 0.5 T magnet. Respiratory compensated T1-weighted, SE and T2-weighted TSE sequences were acquired in all patients. MRP images were obtained by using a respiratory compensated 3D T2-weighted TSE sequence. MRP images were reconstructed with a MIP algorithm. In all cases, urography and/or ascending pyelography were also performed. Images were independently evaluated by two radiologists. RESULTS: The dilated tract ureter and the level of the obstruction could be correctly demonstrated in all cases. The cause of the obstruction was correctly demonstrated by examiner 1 in 90% and by examiner 2 in 88%. The interobserver agreement was high with a kappa-value of 0.96. CONCLUSION: In cases of obstructive hydroureteronephrosis MR imaging, combining MRP and conventional sequences, can be proposed as an accurate technique in the assessment of level and cause of obstruction.
Until recently, MR examinations of the pancreas were limited by motion artifacts, vascular pulsatility and poor spatial resolution. Today, new techniques have been developed, which allow to overcome these problems and provide additional information such as selective images of biliary and pancreatic ducts and vascular structures. MR examinations of the pancreas need to include either breath-hold or nonbreath-hold morphological T1- and T2-weighted images; a contrast agent is required when the study is performed with fast imaging which allow the acquisition of dynamic images in arterial and portal venous phases. Recently, a new liver-specific contrast agent (Mn-DPDP) has been demonstrated to provide selective pancreatic enhancement. As a complement to baseline sequences, MR cholangiopancreatography images can be acquired, possibly integrated by functional examination after secretin administration. Finally, contrast-enhanced MR angiography opens new perspectives for vascular studies, particularly for the locoregional staging of pancreatic cancer.
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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.
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.
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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.
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.
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.
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.
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.
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.
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