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Biomedical subjects

D Caramella

Publications and source records attributed to D Caramella.

At least 37 records · Page 2Linked to original sources
PubMed1999

Laparoscopy and laparoscopic ultrasonography for staging pancreatic cancer: critical appraisal.

A pilot study was designed to elucidate the role of staging laparoscopy for determining resectability in patients with pancreatic cancer. The additional value of laparoscopic contact ultrasonography (LCU) was also evaluated with specific regard to its ability to detect hepatic metastases and assess vascular infiltration of the portomesenteric trunk. A consecutive sample of 50 patients referred for operation of a suspected pancreatic cancer were submitted to preoperative contrast-enhanced high-resolution computed tomography (CT) and staging laparoscopy combined with LCU at a university hospital. For those progressing to exploratory laparotomy, the intraoperative findings relating to tumor diffusion and vascular infiltration were compared to CT, laparoscopic, and LCU data. Analytical description of the laparoscopic findings is given. Row data of predicted versus observed vascular infiltration were tabulated for CT and LCU. The sensitivity, specificity, and overall accuracy of each diagnostic test were calculated for comparative analysis. Laparoscopy alone prevented unnecessary laparotomy in 20% of cases. A complete procedure could not be achieved in 28% of patients. Three false-negative staging results occurred. LCU identified small (benign) hepatic nodules not seen by CT in 8% of patients. Sensitivity, specificity, and overall accuracy for assessing vascular infiltration were 82%, 53%, and 69% for CT and 94%, 80%, and 87% for LCU. Laparoscopy was confirmed to be safe and effective for staging pancreatic cancer. Because of its unique capabilities to detect even small peritoneal tumor deposits a quick exploration immediately before laparotomy is advised in all patients. The additional benefit of a more extensive procedure is not supported by our results. Although LCU appears to define the vascular involvement more accurately than conventional CT, the limitation of getting clinically useful ultrasound data in all the patients suggests its adoption in only a selected population.

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

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

Virtual CT intravascular endoscopy of the aorta: pierced surface and floating shape thresholding artifacts.

Two types of artifacts may appear in virtual computed tomographic endoscopic views of the aorta rendered at different threshold levels: pierced surface and floating shape artifacts. A positive correlation was found between mean attenuation of the aorta and the threshold levels at which these artifacts appeared. The correlation was statistically significant (0.71 < or = r < or = 0.86) for floating shape. An artifact-free threshold range can be predicted on the basis of aortic enhancement.

Adult↗
PubMed1998

CT in vascular pathologies.

Since the introduction of helical scanners, CT angiography (CTA) has achieved an essential role in many vascular applications that were previously managed with conventional angiography. The performance of CTA is based on the accurate selection of collimation width, pitch, reconstruction spacing and scan delay, which must be modulated on the basis of the clinical issue. However, the major improvement of CT has been provided by the recent implementation of many post-processing techniques, such as multiplanar reformatting, shaded surface display, maximum intensity projections, 3D perspectives of surface and volume rendering, which simulate virtual intravascular endoscopy. The integration of the potentialities of the scanner and of the image processing techniques permitted improvement of: (a) the evaluation of aneurysms, dissection and vascular anomalies involving the thoracic aorta; (b) carotid artery stenosis; (c) aneurysms of abdominal aorta; (d) renal artery stenosis; (e) follow-up of renal artery stenting; and (f) acute or chronic pulmonary embolism. Our experience has shown that the assessment of arterial pathologies with CTA requires the integration of 3D post-processing techniques in most applications.

Angiography↗
PubMed1998

Interactive DICOM image transmission and telediagnosis over the European ATM network.

The European High-Performance Information Infrastructure in Medicine, n(o)B3014 (HIM3) project of the Trans-European Network--Integrated Broadband Communications (TEN-IBC) program, started on March 1996 and finished on February 1997, aimed to test the medical usability of the European asynchronous transfer mode (ATM) network in medical image transmission. The Department of Radiology, University of Pisa, Pisa, Italy, and St-Luc University Hospital, Brussels, Belgium, involved in the project as healthcare partners in the radiological domain, established several connection sessions finalized to test the usability of Digital Imaging and Communication (DICOM) image transmission and interactive telediagnosis tools in the daily radiological practice. The Pisa site was connected to the Italian ATM pilot (Sirius Network) through the Tuscany metropolitan area network (MAN), while St-Luc University Hospital was connected to Belgium ATM network through the Brussels MAN. By means of international connections provided by the European JAMES project, a link between the two sites was established, connecting both national ATM networks. Due to the large variety of hardware present in the medical centers, multiplatform software tools were used and tested: central test node (CTN) release 2.8 [3], VAT [6], NV-3.3 [7], and IDI (UCL homemade multiplatform teleradiology tool for interactive visualization and processing of DICOM images). During the telediagnosis session, lead by radiologists in both hospitals, each site submitted neuroradiological clinical cases to the other for remote consultation. The connection, available for a period of two weeks, at 2-Mbit/s bandwidth, allowed the transmission of MR images (256 x 256 x 12 bit) and simultaneous multimedia interactive discussion of the cases. Both off-line transmission and review of the images, using the CTN DICOM transfer routines, and on-line interactive image discussion, using the IDI telediagnosis software, were tested successfully from the technical and medical point of view.

Computer Communication Networks↗
PubMed1997

Spontaneous epidural emphysema and pneumomediastinum during an asthmatic attack in a child.

CT revealed the presence of epidural emphysema as an incidental finding in a 13-year-old boy in whom mild infrequent coughing during an asthmatic attack resulted in a pneumomediastinum and subcutaneous emphysema. Epidural emphysema was not associated with neurological symptoms. The CT images demonstrated the pathway of air leakage from the posterior mediastinum through the intervertebral foramina into the epidural space. Repeat CT showed spontaneous resolution of the epidural emphysema.

Adolescent↗
PubMed1997

Usefulness of echo-color Doppler in differentiating parathyroid lesions from other cervical masses.

The aim of our study was to clarify possible differential color Doppler US features between parathyroid lesions and other cervical masses. A total of 56 parathyroid lesions in 54 patients with primary hyperparathyroidism were preoperatively examined with color Doppler sonography. Color Doppler flow patterns were compared with those of 72 thyroid nodules and 20 cervical lymph nodes. In 38 parathyroid lesions a correlation between color Doppler patterns and size, location, and pathological findings was performed. Color Doppler sonography showed five vascular distribution patterns: pattern I, absence of flow; pattern II, focal peripheral flow ("vascular pole") with arterial Doppler spectrum; pattern III, peripheral flow; pattern IV, internal flow ("parenchymal pattern"); pattern V, peripheral and intranodular flow. Pattern I was not specific for any cervical lesion considered. Conversely, pattern IV was observed solely in parathyroid lesions, and pattern II was observed in only one nonparathyroid lesion (thyroid nodule). Mixed pattern (pattern V) was observed solely in thyroid nodules. In addition, pattern III was a characteristic finding of thyroid nodules and was observed in only one parathyroid lesion. Color Doppler patterns of the parathyroid masses did not correlate with the size of the lesion or pathological findings, but only with the location of the gland. Our study showed that color Doppler assessment of parathyroid lesions is a useful integration of gray-scale US and may be helpful in distinguishing parathyroid lesions from other cervical masses.

Adenoma↗
PubMed1997

Ex-vivo MR imaging of liver intracellular contrast agents.

The objective is to evaluate whether an ex-vivo model can be used to test intracellular contrast agents for MR imaging of the liver. T1 weighted inversion recovery, proton density spin echo and T2* weighted gradient echo images of the liver were acquired at 0.5 T in 10 rats before and 30 min after intravenous injection of 0.075 mmol/kg Gadolinium benzyloxypropionictetraacetate (Gd-BOPTA, n = 5) or 0.015 mmol/kg dextran magnetite (DM, n = 5), Four additional animals served as controls. After exsanguination and perfusion with saline and formalin, specimens of the liver and brain were embedded in an agar gel and examined with MR imaging one to three weeks later using the same protocol. In-vivo, the mean liver signal enhancement caused by Gd-BOPTA in T1, proton density and T2* weighted images was +23%, +28% and -70%, respectively. The mean liver signal enhancement caused by DM was -71%, -76% and -94%. In-vitro, no signal change was seen in the brain of animals injected with Gd-BOPTA and DM as compared to controls. Liver signal was increased by Gd-BOPTA and decreased by DM. Mean liver enhancement rate induced by Gd-BOPTA was +22%, +5% and +27% for T1, proton density and T2* weighted images, respectively. Mean liver enhancement rate induced by DM was -27%, -19% and -31%. MR imaging signal changes induced by liver intracellular contrast agents are still appreciable in an ex-vivo model. The latter might be useful for for preliminary investigation of intracellular contrast agents for MR imaging of the liver.

Animals↗
PubMed1996

Teleradiology: state of the art in clinical environment.

Teleradiology may even be a tautology since communication is an essential part of radiology. The value of a radiological report is strictly dependent on how fast and clearly it is transmitted to the referring physician. The radiologist has therefore learnt to combine imaging expertise with communicator's skills. However, the term teleradiology is usually reserved to define the instances in which computers and digital networks help to reduce the limitations imposed by the physical distance between radiologists and between radiologist and referring physician. In this paper the main clinical applications of teleradiology will be presented, distinguishing between intra-institutional teleradiology (that involves more units belonging to the same department or to the same hospital) and inter-institutional teleradiology (more classically aimed at primary interpretation and subspecialty consultation). Finally a brief mention will be made concerning the potential for Internet to provide radiologists with new professional and educational opportunities.

Computer Communication Networks↗
PubMed1996

Use of a biocompatible fiducial marker in evaluating the accuracy of computed tomography image registration.

RATIONALE AND OBJECTIVES: Accurate registration of computed tomography (CT) images to the patient is crucial for computer-assisted surgery. Markers used in roentgen stereo-grammetric analysis (RSA) can be located in a CT scan using a novel approach and also can be located physically. Roentgen stereo-grammetric analysis data act as "ground truth" for the three-dimensional marker locations. METHODS: Two foam-bone phantoms were marked. The markers were scanned seven times with RSA, three times with axial CT, and contacted four times with a coordinate measuring arm. Root-mean-square (RMS) errors were derived for the registrations. RESULTS: Computed tomography and RSA data register to 0.15 mm RMS error. Computed tomography and arm data register to 0.25 mm. The markers are biocompatible, and the coordinate measuring arm is usable in an operating room. CONCLUSIONS: Typical in vitro registration errors are approximately 2 mm. The authors have developed a marker that provides superior registration, and a procedure that can be used for in vivo studies.

Biocompatible Materials↗
PubMed1996

Transperineal biopsy leads to the diagnosis of genitourinary neurofibromatosis in association with a congenital malformation of the urinary tract.

OBJECTIVE: A case of genitourinary fibromatosis with associated anomalies is presented. METHODS: Clinical evaluation included ultrasonography, urography, CT scan and MR image. Ultrasonography-guided perineal biopsy was performed with a 14-gauge Tru-cut needle. RESULTS: Rectal examination revealed a very hard prostatic mass in the 22-year-old patient. The histological result and clinical data indicated the diagnosis of genitourinary von Recklinghausen disease. CONCLUSION: We report a very rare case of genitourinary neurofibromatosis associated with congenital anomalies of the urinary tract. The diagnosis was obtained with US-guided transperineal biopsy.

Adult↗
PubMed1996

Small hepatocellular carcinoma. Detection with US, CT, MR imaging, DSA, and Lipiodol-CT.

Twenty-two patients with 37 small (3 cm or less) nodular lesions of hepatocellular carcinoma (HCC) were examined with ultrasonography (US), CT, MR imaging, digital subtraction angiography (DSA), and CT following intraarterial injection of Lipiodol (Lipiodol-CT). All patients subsequently underwent surgery, and the gold standard was provided by intraoperative US. The detection rate was 70% for US, 65% for CT, 62% for MR imaging, 73% for DSA, and 86% for Lipiodol-CT. A significant difference (p < 0.05) was observed between the detection rate of Lipiodol-CT and the detection rates of all the other imaging modalities. The difference was even more manifest (p < 0.02) when only lesions smaller than or equal to 1 cm were considered. It is concluded that Lipiodol-CT is the single most sensitive examination to detect small nodules of HCC. It should therefore be considered a mandatory step in the preoperative evaluation of patients with HCC considered to be surgical candidates after noninvasive imaging studies.

Aged↗