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Biomedical subjects

C Bartolozzi

Publications and source records attributed to C Bartolozzi.

At least 37 records · Page 2Linked to original sources
PubMed2000

MnDPDP-enhanced MRI vs dual-phase spiral CT in the detection of hepatocellular carcinoma in cirrhosis.

The objectives of this study were twofold: (a) to assess safety and tolerability of the hepatobiliary MR contrast agent MnDPDP; and (b) to investigate the sensitivity of MnDPDP-enhanced MRI, in comparison with dual-phase spiral CT, in the detection of hepatocellular carcinoma (HCC) in cirrhosis. Fifty patients with liver cirrhosis and histologically proven HCC were enrolled in a prospective phase-IIIB clinical trial. All patients underwent evaluation with dual-phase spiral CT and pre-contrast and post-contrast MRI at 1.5 T. The MR examination protocol included spin-echo (SE) and gradient-recalled-echo (GRE) T1-weighted images acquired before and 60-120 min after administration of 0.5 micromol/kg (0.5 ml/kg) MnDPDP (Teslascan, Nycomed Amersham, Oslo, Norway); and fast T2-weighted SE images obtained solely before contrast injection. Gold standard was provided by findings at Lipiodol CT in combination with follow-up spiral CT studies, which were repeated at 4-month intervals over a 10- to 27-month (mean +/- SD 20.1 +/- 5.1 months) follow-up period. No serious adverse event occurred. Eighty tumors ranging 0.8-9.1 cm in diameter (mean +/- SD 3.2 +/- 2.4 cm) were detected by Lipiodol CT or confirmed as cancerous foci by follow-up CT studies. Pre-contrast MRI detected 38 of 80 lesions (48%); MnDPDP-enhanced MRI, 65 of 80 lesions (81%); pre-contrast plus post-contrast MRI, 69 of 80 lesions (86%); and dual-phase spiral CT, 64 of 80 lesions (80%). The difference between unenhanced and MnDPDP-enhanced MRI was statistically significant (p < 0.001). The difference between MRI (pre-contrast plus post-contrast) and dual-phase spiral CT was not statistically significant (p = 0.33). The confidence in the final diagnosis, however, was significantly higher for MRI as compared with spiral CT (p<0.001). MnDPDP is a safe and well-tolerated hepatobiliary MR contrast agent. Magnetic resonance imaging with use of MnDPDP is significantly more sensitive than unenhanced MRI and as good as dual-phase spiral CT for detection of HCC in cirrhosis.

Carcinoma, Hepatocellular↗
PubMed2000

High-resolution magnetic resonance and volume rendering of the labyrinth.

Our aim was to verify the feasibility of volume rendering (VR) of high-resolution magnetic resonance (HR-MR) data sets of the labyrinth. We retrospectively reviewed the HR-MR data sets of 16 consecutive patients with no MR evidence of labyrinthine pathology. High-resolution MR data sets were obtained by means of a 3D T2-weighted FSE sequence with the use of a 3-in. circular surface coil for signal reception, and processed with a high-end workstation. Two reviewers performed separately VR of the labyrinth by selecting the signal intensity interval for attribution of opacity and transparency. Concerning the time taken for definition of the volume of interest, the two observers needed, respectively, 28.9 and 33.1 min (SD +/- 8.7-9.5 min), whereas the time taken for VR was respectively, 26 and 33.2 min (SD +/- 8.8-8.9 min). Concerning the selection of the signal intensity interval, the two observers had, respectively, 86.4 and 88.7 mean lower threshold (SD +/- 34.5-33.5), 488.9 and 495.4 mean upper threshold (SD +/- 56.3-53.8). In our experience, we have found VR of HR-MR to offer a reliable and reproducible technique for producing 3D representations of the labyrinth. The VR algorithms use all data within the imaging volume and optimize the dynamic range ascribed to the object being visualized.

Adolescent↗
PubMed2000

Teleradiology in Europe.

The new concept of teleradiology is centered on the consideration that it involves management of medical information rather than the simple transmission of diagnostic images from one location to another. Teleradiology must therefore be able to contribute to the seamless integration of the digital environment in which medical data are managed throughout and beyond the hospital, generating value added services for the patients as well as prospective economical benefits for the institution. In this perspective the evolution of telecommunication with the spectacular success of mobile telephony and Internet will play and increasingly important role, by allowing further development in the exchange of multimedia medical information on a regional as well as international level. However, new responsibilities are being given to the radiologists, who must take all necessary technical and organizational actions in order to avoid that the digital management of data may endanger the confidentiality and the integrity of patients' data.

Computer Security↗
PubMed2000

Contrast-enhanced color Doppler ultrasonography in suspected parathyroid lesions.

PURPOSE: To assess the usefulness of US contrast media in the evaluation of patients with primary hyperparathyroidism, with a nodule showing US features of a primary parathyroid lesion but lacking the color Doppler US appearance of a parathyroid mass. MATERIAL AND METHODS: Thirteen patients (7 female, 6 male; age range 51-79 years) were examined with US before and after administration of a stabilized galactose-based microbubble contrast agent. Ten patients underwent surgery and the final histological examination demonstrated parathyroid adenoma in 9 cases and a mesenchymal benign nodule in 1 case. Three nodules were proved to be of thyroid origin at fine-needle aspiration biopsy. RESULTS AND CONCLUSION: The use of a US contrast agent resulted in a diagnostic gain compared to unenhanced studies in 12/13 cases. Color Doppler findings characteristic of parathyroid lesions were observed in 7/13 cases, of thyroid nodules in 4/13 cases, and nonspecific patterns in 2/13 cases. Contrast-enhanced color Doppler US can be proposed in selected patients in whom unenhanced color Doppler provides uncertain findings. Its ideal application should be the evaluation of cervical lesions without detectable intranodular flow at unenhanced Doppler studies. In these cases, the contrast agent helps in visualizing typical color Doppler signals of the parathyroid lesions ("vascular pole" and "mixed pattern").

Adenoma↗
PubMed2000

Focal liver lesions: evaluation of the efficacy of gadobenate dimeglumine in MR imaging--a multicenter phase III clinical study.

PURPOSE: To evaluate gadobenate dimeglumine (Gd-BOPTA) for dynamic and delayed magnetic resonance (MR) imaging of focal liver lesions. MATERIALS AND METHODS: In 126 of 214 patients, MR imaging was performed before Gd-BOPTA administration, immediately after bolus administration of a 0.05- mmol/kg dose of Gd-BOPTA, and 60-120 minutes after an additional intravenously infused 0.05-mmol/kg dose. In 88 patients, imaging was performed before and 60-120 minutes after a single, intravenously infused 0.1-mmol/kg dose. T1- and T2-weighted spin-echo and T1-weighted gradient-echo images were acquired. On-site and blinded off-site reviewers prospectively evaluated all images. Intraoperative ultrasonography, computed tomography (CT) during arterial portography, and/or CT with iodized oil served as the reference methods in 110 patients. RESULTS: Significantly more lesions were detected on combined pre- and postcontrast images compared with on precontrast images alone (P <. 01). All reviewers reported a decreased mean size of the smallest detected lesion and improved lesion conspicuity on postcontrast images. All on-site reviewers and two off-site reviewers reported increased overall diagnostic confidence (P <.01). Additional lesion characterization information was provided on up to 109 (59%) of 184 delayed images and for up to 50 (42%) of 118 patients in whom dynamic images were assessed. Gd-BOPTA would have helped change the diagnosis in 99 (47%) of 209 cases and affected patient treatment in 408 (23%) of 209 cases. CONCLUSION: Gd-BOPTA increases liver lesion conspicuity and detectability and aids in the characterization of lesions.

Adult↗
PubMed2000

Percutaneous radio-frequency thermal ablation of nonresectable hepatocellular carcinoma after occlusion of tumor blood supply.

PURPOSE: To evaluate the usefulness of percutaneous radio-frequency (RF) thermal ablation of nonresectable hepatocellular carcinoma (HCC) after occlusion of the tumor arterial supply. MATERIALS AND METHODS: Sixty-two patients with cirrhosis and biopsy-proved HCC underwent RF ablation after interruption of the tumor arterial supply by means of occlusion of either the hepatic artery with a balloon catheter (40 patients) or the feeding arteries with gelatin sponge particles (22 patients). RESULTS: After a single RF procedure in 56 patients and after two procedures in six patients, spiral computed tomography (CT) demonstrated a nonenhancing area corresponding in shape to the previously identified HCC, which was suggestive of complete necrosis. No major complications occurred. Two patients subsequently underwent surgical resection; the remaining 60 patients were followed up with spiral CT. During a mean follow-up of 12.1 months, 11 HCC nodules showed areas of local progression; 49 were identified as nonenhancing areas with a 40%-75% reduction in maximum diameter. The 1-year estimate of failure risk was 19% for local recurrence and 45% for overall intrahepatic recurrence. The estimated 1-year survival was 87%. Histopathologic analysis of one autopsy and two surgical specimens revealed more than 90% necrosis in one specimen and 100% necrosis in two. CONCLUSION: HCC nodules 3.5-8.5 cm in diameter can be ablated in one or two RF sessions after occlusion of the tumor arterial supply.

Aged↗
PubMed2000

Oral doxifluridine in advanced hepatocellular carcinoma: A phase II study.

Hepatocellular carcinoma (HCC) remains one of the most common neoplasms in the world. Doxifluridine is an oral fluoropyrimidine derivative activated to 5-fluorouracil by uridine phosphorylase which is more expressed in malignant cells. Therefore, we conducted a phase II study to evaluate the activity of oral doxifluridine in patients with advanced hepatocellular carcinoma. Twenty-five advanced hepatocellular carcinoma patients entered the study; doxifluridine was given orally at the initial daily total dose of 2,250 mg for 4 consecutive days every week. All patients are evaluable for toxicity: these included mainly grade 1-2 (WHO) diarrhea, stomatitis, nausea and vomiting; 4 patients (16%) experienced grade 3-4 diarrhea. Twenty-four patients are evaluable for response and 1 complete and 3 partial responses have been observed (response rat 17%, 95% confidence interval: 5-37). Oral doxifluridine at the dose and schedule we used, although having only modest activity in advanced HCC, may represent an alternative to other frequently used chemotherapeutic agents, because of its favorable toxicity profile and its simple route of administration.

Administration, Oral↗
PubMed2000

MR virtual endoscopy of the upper urinary tract.

OBJECTIVE: We investigated the feasibility of applying surface-rendered virtual endoscopy to the visualization of the upper urinary tract by processing unenhanced MR urography data sets. SUBJECTS AND METHODS: Twenty-six patients, having neoplastic lesions (n = 9), calculi (n = 8), pelviureteric junction stenoses (n = 4), postoperative fibrotic strictures (n = 3), and extrinsic compressions of the ureter (n = 2), underwent unenhanced MR urography. Virtual endoscopy of the upper urinary tract was obtained using a thresholding technique and surface-rendering MR urography data sets. RESULTS: Virtual endoscopy of the renal pelvis and calices was feasible in all cases on the side of the urinary obstruction. Virtual endoscopy of the ureter was obtained for a diameter of at least larger than 5 mm. The nondilated side could be partially explored in 11 cases (43%). The mean virtual endoscopy threshold required for the visualization of the urinary tract was 157.36-159.94. The mean time for virtual endoscopy was 13.8 min. Endoluminal masses were found in three (12%) of 26 cases on the renal pelvis (corresponding to neoplastic lesions), and occlusions, in 23 (88%) of 26 on the pelviureteric junction and ureter (neoplastic lesions and other abnormalities). CONCLUSION: Virtual endoscopy of MR urography data sets is feasible in patients with urinary tract dilatation. Virtual endoscopy displays the renal pelvis, calices, and ureter and, moreover, can show endoluminal changes caused by abnormalities.

Diagnostic Techniques, Urological↗
PubMed2000

Virtual endoscopy of the middle and inner ear with spiral computed tomography.

OBJECTIVE: To evaluate the inner anatomy of the auditory apparatus by means of virtual endoscopy of spiral computed tomography (CT) data sets. BACKGROUND: Virtual endoscopy permits simulation of the fiberoptic endoscopy perspective by processing CT or magnetic resonance images. METHODS: Seven formalin-fixed specimens of human mastoid were scanned with spiral CT with the following protocol: beam collimation 1 mm, pitch ratio 1, reconstruction spacing 0.2 to 0.5 mm, field of view 90 mm. For the generation of endoscopic views of the auditory spaces, the axial images were processed with Navigator software 2.0 running on UltraSparc I workstation. RESULTS: Virtual endoscopy allowed the demonstration of the external auditory canal, the head and handle of the malleus, the stapes and incudostapedial articulation, the corpus, the long process of the incus with its lenticular process and the short limb, the malleoincudal articulation, the rounded promontory, the round and oval windows, and Prussak's space. From inside the basal turn of the cochlea, virtual endoscopy showed the orifices of the fenestrae cochlea and vestibuli, the origin of the lateral and the anterior semicircular canals, and the basal turn of cochlea. The optimal perspectives that allowed demonstration of the anatomical details of the middle and inner ear are described. CONCLUSION: Virtual endoscopy allows the generation of inner views of the auditory spaces. This new method of image processing can be proposed as an integrative tool of spiral CT imaging.

Culture Techniques↗
PubMed2000

Laparoscopic radiofrequency thermal ablation of hepatocarcinoma: preliminary experience.

The objective was to evaluate the feasibility, safety, and effectiveness of radiofrequency thermal ablation (RFT), performed during laparoscopy with a cooled-tip electrode needle, in the treatment of neoplastic hepatic focal lesions. Seven patients with hepatocarcinoma (10 hepatic lesions) were treated during laparoscopy with RFT using a 100-watt RF generator and 17-gauge, dual-lumen, cooled-tip electrode needles with a 3-cm exposed tip. The mean exposure time was 12 minutes for each needle insertion. Spiral computed tomography scanning detected complete tumor necrosis in nine lesions; in one lesion, peripheral neoplastic tissue was detected, and percutaneous RFT was performed. Two patients during follow-up developed two new neoplastic lesions, treated with percutaneous ethanol injection. No recurrences of the treated lesions were seen after 6 months of follow up. Intraoperative RFT with a cooled-tip electrode needle is a safe and effective local treatment of hepatic focal lesions during laparoscopic surgery. Possible indications are large hepatocarcinoma (>5 cm), superficial lesions, multiple lesions, or tumor located near vascular or biliary structures.

Aged↗
PubMed1999

Endorectal coil MR imaging findings in hemospermia.

The purpose of this study was to illustrate the spectrum of abnormalities found at endorectal coil magnetic resonance (MR) imaging in patients with hemospermia. Ninety patients aged between 23 and 71 years (mean age 41 years) presenting with hemospermia underwent evaluation with endorectal coil MR imaging at 1.5 T. Duration of hemospermia ranged between 5 days and 4 years (mean 15 months). MR examination protocol included T1-weighted spin-echo (SE) and T2-weighted fast SE MR images obtained in the sagittal, coronal, and axial planes. Abnormalities were observed on endorectal-coil MR images in 49 of 90 patients (54%). Blood within the seminal vesicle or the ejaculatory duct was recognized in 23 of 90 patients (25%). Dilatation of the seminal vesicles or the ejaculatory duct was observed in 31 of 90 patients (34%). Cystic lesions were identified in 14 cases, eight of which involved the utriculus and six the ejaculatory duct. Calculi within the seminal vesicles were depicted in seven patients. No malignant disease was demonstrated. In conclusion, despite the evidence that hemospermia is most often a benign and self-limiting condition, we found that endorectal coil MR imaging can detect abnormal findings in more than half of the patients, and may be helpful in assessing the level at which hemorrhage occurred and in defining the cause of the disease.

Adult↗
PubMed1999

Detection of accessory renal arteries with virtual vascular endoscopy of the aorta.

PURPOSE: To evaluate the diagnostic accuracy of virtual vascular endoscopy (VVE) in the detection of accessory renal arteries. METHODS: We retrospectively reviewed the CT angiography data sets of 67 patients (29 male and 38 female; age range 17-72 years, mean age 53 years) imaged for the study of the renal arteries, and affected by renovascular hypertension. All patients also had intraarterial digital subtraction angiography (DSA). CT angiography data sets were processed to obtain maximum intensity projection (MIP) and surface-rendered VVE of the aorta. Axial images, MIP, and VVE were evaluated separately and in combination in the detection of accessory renal arteries. Their results in terms of sensitivity and specificity were then compared with DSA. RESULTS: Axial images had a sensitivity of 88% and specificity of 94% for accessory renal artery detection, MIP had a sensitivity of 88% and specificity of 98%, and VVE had a sensitivity of 63% and a specificity of 88% (p < 0.05 vs DSA), but these increased to 88% and 98% respectively if endoscopic views were integrated with the other display techniques. CONCLUSION: VVE based on surface rendering does not add substantial benefits to CTY angiography; by contrast MIP is the most accurate display technique for the detection of accessory renal arteries.

Adolescent↗
PubMed1999

Pseudoaneurysm of the abdominal aorta: evaluation with virtual angioscopy of spiral-CT data sets.

We describe a case of graft-related pseudoaneurysm of the abdominal aorta evaluated with spiral CT and DSA. Spiral CT data sets were processed to obtain surface-rendered internal views (virtual angioscopy, VA) of the graft and the pseudoaneurysm, and to demonstrate from inside the lumen the site of dehiscence. A jet flow phenomenon inside the pseudoaneurysm was observed at DSA. Spiral-CT axial images, multiplanar volume reconstructions with maximum intensity projections, and shaded surface display showed the site of rupture. The VA findings were: (a) from inside the graft lumen, the evidence of a communication canal between the graft and the pseudoaneurysm; and (b) from inside the pseudoaneurysm, the presence of a jet flow. The VA findings showed good correlation with those obtained with the other imaging techniques.

Aneurysm, False↗
PubMed1999

Abdominal MR: liver and pancreas.

Following the introduction of rapid, high-quality scan techniques and the development of new, tissue-specific contrast agents, the applications of MRI for abdominal imaging are experiencing unprecedented growth. This article examines the current status of liver and pancreatic MRI, highlighting technical and methodological approach, use of contrast agents, and main clinical applications. The MRI technique appears to be the ideal diagnostic tool for detection and characterization of benign and malignant liver neoplasms, and for evaluating tumor response after nonsurgical treatments. Dynamic imaging after bolus injection of a gadolinium chelate is currently a fundamental component of an MRI examination of the liver in many instances. Optimal dynamic scanning depends on the use of a multisection spoiled gradient-echo technique that allows one to image the entire region of interest during a single suspended respiration. Images are obtained during four phases relative to the injection of the contrast agent: precontrast, arterial (pre-sinusoidal), portal (sinusoidal), and delayed (extracellular) phase. Liver-specific contrast agents, including hepatobiliary agents and reticuloendothelial system-targeted iron oxide particles, however, may offer advantages over gadolinium chelates in some clinical settings. Computed tomography is still preferred to MRI for imaging the pancreas. However, state-of-the-art MRI may currently be at least as accurate as spiral CT for depiction of inflammatory and neoplastic pancreatic diseases. Moreover, MRI has the advantage of allowing simultaneous investigation of the biliary tree, owing to cholangiopancreatography techniques. Hence, a comprehensive assessment of most pancreatic diseases can be achieved with a single examination.

Contrast Media↗
PubMed1999

MR virtual endoscopy of the pancreaticobiliary tract.

PURPOSE: To evaluate the feasibility of surface-rendered magnetic resonance virtual endoscopy (MRVE) of magnetic resonance cholangiopancreatography (MRCP) data sets. We retrospectively reviewed MR cholangiopancreatography data sets of 120 patients with biliary stone (n=40), inflammatory ampullary stenosis (n=12), pancreatic tumor (n=8), cholangiocarcinoma (n=7), stenosis of surgical bilio-enteric anastomosis (n=4), extrinsic localized common bile duct stenosis (n=2), ampullary carcinoma (n=2), pancreatic duct stone (n=1), tumor of the gallbladder (n=1), and normal pancreaticobiliary tree (n=43). MRVE views were generated with Navigator software. Segmentation of the acquired data sets was performed with a thresholding technique. Navigation sequences were simulated through the entire biliary tract. MRVE was obtained in 27 (63%) of the 43 normal patients. Endoscopic views were generated in all 77 patients with partial or complete obstruction of the pancreaticobiliary tree. Among these, three groups of patterns were identified: 36 (47%) endoluminal masses (polyp-like masses), 17 (22%) luminal stenoses, 24 (31%) luminal occlusion. In 29 cases, hole artifacts through the internal wall were observed and interpreted as mistakes of segmentation. MRVE proved to show the internal anatomy of the biliary tract and endoluminal changes due to pathological condition. Further investigations are needed to test the usefulness and the potentialities of this technique.

Adolescent↗
PubMed1999

Choledocolithiasis: diagnostic accuracy of MR cholangiopancreatography. Three-year experience.

The purpose of this study was to evaluate the diagnostic accuracy of MR cholangiopancreatography (MRCP) in the detection of common bile duct stones. A series of 286 consecutive patients were referred for MRCP, that was performed with a 1.5 T MR unit, through a non-breath-hold, respiratory-triggered, fat-suppressed, two-dimensional, heavily T2-weighted fast spin-echo sequence in the coronal plane. Axial T1 and T2-weighted sequences were first obtained. Axial, coronal, and Maximum Intensity Projection images were evaluated by three independent readers, who were asked to determine whether stones were present or not inside the biliary tract. The findings of MRCP images were compared with endoscopic retrograde cholangiopancreatography, percutaneous trans-hepatic cholangiography, intra-operative cholangiography, surgical, or imaging follow-up findings. Two-hundred and seventy-eight out of 286 MRCP examinations were judged diagnostic by the three reviewers. Among the 278 patients included in our study group, biliary tract lithiasis was proved in 76 cases (27%). On the basis of reviewers' reading, MRCP had sensitivity 92-93%, specificity 97-98%, positive predictive value 91-93%, negative predictive value 97-98%, and the diagnostic accuracy ranged between 95% and 96% in the detection of calculi. Interobserver agreement was excellent (K = 0.84, kappa statistic). MRCP showed a high diagnostic accuracy and an excellent inter-observer agreement in the detection of common bile duct stones.

Adolescent↗
PubMed1999

Noninvasive assessment of renal artery stenosis: current imaging protocols and future directions in ultrasonography.

Doppler ultrasound is one of many modalities that have been evaluated for the detection of renal artery stenosis. The lack of standardization in examination protocols and diagnostic criteria, as well as the wide differences in reported accuracy among different laboratories have, however, prevented universal acceptance of this technique as a reliable screening test for renal artery stenosis. The recent introduction of ultrasound contrast agents has substantially expanded the potential of color Doppler ultrasound. The use of microbubble echoenhancers in combination with harmonic Doppler imaging has been shown to improve diagnostic confidence by improving the operator's ability to visualize the renal arteries, and to significantly reduce the number of equivocal examinations. Moreover, contrast-enhanced Doppler ultrasound can provide functional information through analysis of renal time-intensity wash in/wash out curves. State-of-the-art contrast-enhanced Doppler ultrasound seems to have the potential to become a useful screening test for patients at risk from renovascular hypertension.

Blood Flow Velocity↗