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Biomedical subjects

A Carriero

Publications and source records attributed to A Carriero.

At least 19 recordsLinked to original sources
PubMed1992

Measurement of segmental transit through the gut in man. A novel approach by the biomagnetic method.

The techniques commonly used to evaluate the transit of contents through the gut feature some limitations for being either inaccurate, invasive, inconvenient, or potentially dangerous for the subjects. Aim of this study was to establish a safe, noninvasive and accurate technique for the measurement of segmental oroanal transit time. We localized an orally ingested magnetic marker by means of a biomagnetic instrumentation that allows us to identify in a three-dimensional pattern the position of a biomagnetic source inside the body. The biomagnetic localizations were compared with the anatomical data obtained by magnetic resonance imaging investigations. The study was performed in 12 healthy subjects, and scans were taken every hour up to the arrival of the marker into the cecum; thereafter, scans were taken every 4 hr up to the elimination of the marker. In 99% of the isofield maps obtained from each field scan, the marker was localized within the bowel walls. The mean oroanal transit time was 56 +/- 5 hr, the mouth-to-cecum transit time was 13 +/- 1.7 hr, and the total colonic transit time was 43.5 +/- 5 hr (mean +/- SEM). Segmental colon transit did not show major differences among the regions considered, although most of the time was spent in the right colon. In fact, a good correlation was found between transit time through the right colon and oroanal and total colonic transit (r = 0.77, P < 0.02, r = 0.79, P < 0.02 respectively). In conclusion, this method might be a safe alternative to the techniques presently used in the clinical setting for the measurement of intestinal transit.

Administration, Oral↗
PubMed1992

[Magnetic resonance angiography with gadolinium (Gd-DTPA) versus baseline magnetic resonance angiography in the study of the intracranial circulation].

The authors evaluated the role of GdDTPA in magnetic resonance angiography (MRA) of intracranial vessels. Fifteen patients affected with different conditions underwent MRA of intracranial vessels before and after paramagnetic contrast medium infusion. A superconductive 1.5-T magnet (Magnetom Siemens) was used, and a head circular coil, together with the 3DFT TOF technique. The enhanced exam was performed following the infusion of 0.2 ml/kg of GdDTPA in about 2 minutes, with simultaneous MRA image acquisition. To compare enhanced with unenhanced images relative to signal intensity, the signal increase at the basilar artery and carotid sinus was studied, together with signal-to-noise (S/N) ratio and spatial resolution. During acquisition, enhanced MRA images at the basilar artery showed a mean intensity value of 423.8 +/- 33.2 vs 357.8 +/- 53.2 of unenhanced scans; a statistically significant difference (p < 0.05; p < 0.01) was observed in favor of enhanced images. At the carotid sinus, enhanced MRA showed 184.5 +/- 28.4 mean intensity value vs 190.5 +/- 19.8 of unenhanced exams; no statistically significant difference was observed (p < 0.05; p < 0.01) in favor of unenhanced exams. At the basilar artery the S/N ratio of baseline exams was 1.9 vs 2.2 for enhanced scans; at the carotid sinus S/N ratio was 2.4 (unenhanced) vs 2.3 (enhanced). Thus, MRA allowed better visualization of peripheral branches of arterial (95.6%) and venous vessels, which unenhanced scans always failed to depict; on the other hand, enhanced images exhibited poorer definition of arterial vessels which were never isolated from the background. The simultaneous visualization of arterial and venous vessels, of choroid plexus and mucosae, affect the quality of enhanced angiograms. At present, GdDTPA is the sole contrast medium suitable for MRA intracranial vessels even though, due to its pharmacokinetic features, it is not the optimum medium.

Adult↗
PubMed1992

[Magnetic resonance venogram of the intracranial circulation. Technique, anatomy, indications].

The authors standardized the MR-venography technique in 50 patients for the study of intracranial venous circulation and identified, for each vessel and district, the best acquisitions and rotations. The possible diagnostic applications of MR-angiography were also evaluated. The examinations were performed with a 1.5-T superconductive magnet (Magnetom, Siemens) and linear head coil. Fifty subjects were examined--40 healthy volunteers, 5 patients affected with multiple sclerosis (MS) and 5 patients with pathologic conditions of intracranial venous circulation. The 40 volunteers were studied with FISP 2D techniques; in 10 of them the images were acquired on the coronal plane, in 10 on the sagittal plane, in 10 on the axial plane, and in 10 on the axial plane after a 90 degrees saturation pulse to obtain saturation of the arterial signal. The FISP 3D sequence acquired on the axial plane and after i.v. gadolinium administration was used in the study of the 5 patients affected with MS. In the post-processing all the acquired images were rotated on the axial (z), sagittal (x), and coronal (y) axes, from 0 degrees to 180 degrees with a 15 degrees step. Data correlation showed that the veins of the postero-superior group were well visualized with 2D sequences on the sagittal plane and rotated, in the post-processing, on the z axis 0 degrees-180 degrees and on the coronal axis from -45 degrees to 45 degrees. The veins of the antero-inferior group were clearly demonstrated with 2D sequences acquired on the axial plane and after arterial saturation, rotated in the post-processing on the sagittal and coronal axes from -45 degrees to 45 degrees. Small veins--i.e., veins of the scalp, diploic and emissary veins, and inferior sagittal sinus--were well visualized with 2D sequences acquired on the coronal plane an rotated during post-processing on the z and x axes 0 degrees-180 degrees following i.v. injection of gadolinium. MR-venography is a new technique which can be useful to answer such specific diagnostic questions as the staging of brain neoplasm contiguous to intracranial venous vessels, the study of arteriovenous malformations and thrombosis on intracranial venous sinuses, as it has been demonstrated in 5 pathologic cases.

Cerebral Veins↗
PubMed1991

[Cerebrovascular pathology. Comparison of magnetic resonance and magnetic resonance angiography].

After making the visualization of the intracranial circulation possible without contrast media, the radiologist is now evaluating the diagnostic role of the different techniques of MRA. Attempts are also being made to characterize the main patterns of intracranial vascular diseases. The authors examined, with 3D TOF MRA, 40 patients presenting with 50 vascular lesions on MRI scans. Twenty of 40 patients were also studied with angiography. Seventeen aneurysms were detected, together with 3 stenoses of the cerebral arteries, 13 arteriovenous malformations, 12 dolichobasilar arteries, 3 postoperative and 2 post-embolization controls. MRI was performed with a superconductive magnet (1.5 T), a dedicated coil and gradient-echo 3D TOF FT sequences. The refocused sequence for flux, FISP 3DFT, required the following parameters: TR = 0.04 s, TE = 10 ms, flip angle = 15 degrees, 256 x 256 matrix, 1 acquisition. The 64-80 mm volume along the axial plane was divided so that an actual 1-mm thickness was excited. In post-processing, the maximum-intensity projection was employed on the axial plane 0 degrees-90 degrees (15 degrees interval). In the various conditions, the results obtained with MRA were correlated and compared with MRI findings. MRA provided useful additional information in 27.4% of cases in the study of aneurysms, arteriovenous malformations, vascular occlusion and dolichobasilar arteries, as well as in the follow-up of these lesions. MRA is currently suggested in the evaluation of cerebral circulation and is considered a complementary technique to MRI. MRA is also to be used preliminary to angiography.

Arteriovenous Malformations↗
PubMed1991

[Comparison of magnetic resonance angiography and digital angiography of the epiaortic vessels].

Atheromasic lesions and other pathologic conditions of the arterial vessels of the neck are the most frequent causes of cerebrovascular disease. Diagnostic imaging currently employs digital subtraction angiography (DSA), Doppler, and color-Doppler US to study these conditions. Digital subtraction intraarterial angiography (DSAA) can provide both an early diagnosis and an accurate preoperative depiction of neck vessels; however, in spite of its effective value, it still remains an invasive technique. Magnetic Resonance angiography (angio-MR) is the latest technique allowing the depiction of neck vessels morphology. It shares with digital angiography the capability of supplying spatial depiction of all the examined vascular structures, and with US its noninvasiveness. The authors investigated angio-MR capabilities in providing accurate and detailed images of neck arteries; the images were then compared with DSA ones. Thirty patients with cerebrovascular diseases were studied. MR imaging was performed with a 1.5 T unit with a dedicated coil, and gradient-echo sequences were employed. Refocused sequences for flow were acquired on both the coronal and the sagittal planes, with the following parameters: TR 40, TE 10, flip angle 25 degrees, acquisition volumes 80-35 mm, 64-15 frames. Digital angiography demonstrated 101 vascular lesions: 27 slight stenoses (less than 30%), 19 mild stenoses (31-70%), 12 severe stenoses (71-99%), 7 occlusions, 14 coilings, 7 kinkings, and 15 hypoplasias of vertebral artery. In slight stenoses, angio-MR underestimated the condition in 11/27 patients. In mild and severe stenoses, as well as in occlusive diseases, angio-MR tended to overestimate the condition. In coiling, kinking, and hypoplasia, angio-MR yielded the same results as DSA.

Angiography, Digital Subtraction↗
PubMed1990

Familial occurrence of gastric cancer in the 2-year experience of a population-based registry.

The authors studied the familial occurrence of tumors in 154 individuals with gastric cancer by reviewing the clinical data and the genealogical tree of all patients registered in 1986 through 1987 in the Local Health Care District of Modena, Italy, for cancer of the stomach. Crude and age-adjusted (world population) incidence rates of gastric cancer were 34.0 and 21.4 new cases/100,000/year, respectively, in men, and 24.5 and 10.9 in women, respectively. Among first-degree relatives of the registered patients there were 30 cases of gastric carcinoma versus 15 cases in a control group matched for age and sex (Mantel-Haenszel odds ratio [M-H OR] 3.14, P less than 0.01). This excess of gastric neoplasms was observed in siblings (17 versus 7, M-H OR 4.33, P less than 0.02) but not in parents (13 versus 8, not significant). Besides gastric cancer, there was no significant excess of other type of tumors in case families. The familial occurrence of gastric cancer tended to be more frequent in patients with "diffuse" carcinoma (52%) than in subjects with "intestinal" cancer (33%), although the difference was not statistically significant. In conclusion, the current investigation suggests that a "family history" for gastric neoplasms is usually observed in approximately 10% to 15% of the registered cases. As already described for other common malignancies, therefore, the familial occurrence of gastric carcinoma suggests the existence of a genetic susceptibility to cancer of the stomach, at least in a fraction of these patients.

Adult↗
PubMed1990

[New approaches in the diagnosis of pelvic recurrence after the Miles intervention].

The Authors refer some diagnostic and therapeutic observations about pelvic-perineal recurrence after abdominal-perineal excision of rectum (AAP). They analyze new possibilities of diagnostic instrumentation, in particularly TC and RM scanner, comparing the results and valuing the sensibility and specificity in a selected group of patients.

Adult↗
PubMed1990

[Familial paragangliomas of the neck: integrated imaging and the planning of family screening].

The authors have studied a case of familial paraganglioma of the neck with integrated diagnostic methods: sonography (US) and MR imaging. They verified, through personal experience and literature review, the utility of familial diagnostic screening and of clinico-diagnostic screening planning. The main aim was to detect the elements which could help plan the screening, thus improving the early diagnosis of paragangliomas.

Adult↗
PubMed1990

[Magnetic resonance angiography of the neck vessels: technique and anatomy].

The authors identified the standard projections for studying neck vessels with magnetic resonance angiography. Sixty volunteers underwent angio-MR of the arterial neck vessels with FISP 3D FT sequences obtained on the coronal and sagittal planes. The gradient-echo sequence (FISP 3D FT) was acquired with TR = 0.04-0.08 s and TE = 15 ms, with 25 degrees flip angle. Single excitated slices of thickness ranging from 1-2 mm were included in the acquisition volume. These sequences were subsequently processed by the maximum intensity projection method. Two radiologists examined our results to choose the optimal projections. We used a semiquantitative scale which allowed us to distinguish 3 different diagnostic levels for each projection: well-visualized vessels, poorly-visualized, and non-visualized ones. For each section axial rotations were performed ranging from 0 degree to 180 degrees, with 15 degrees intervals. On the coronal plane, rotations from -45 degrees to 45 degrees were the optimal ones to visualize the studied vessels. The 0 degree-15 degrees-30 degrees-45 degrees-135 degrees-165 degrees-180 degrees projections allowed the common carotids to be clearly demonstrated together with the vertebral arteries. The other projections appeared to be useless for diagnostic purposes. On the sagittal plane, rotations from 60 degrees to 120 degrees were the optimal ones. The 90 degrees projection allowed the demonstration of all the big arterial vessels of the neck, including carotid bifurcation and internal and external carotids. The assessment of the optimal diagnostic projections for angio-MR of the neck vessels is helpful to reduce post-processing time. As a matter of fact, the immediate visualization, during the examination, of the standard projections allows further acquisitions to be obtained--if needed--to try to solve specific diagnostic doubts.

Adult↗
PubMed1990

[Magnetic resonance angiography of the neck vessels: imaging optimization].

The neck vessels of 60 patients were studied by means of magnetic resonance angiography, with gradient-echo FISP sequences with short TR and TE and with a 25 degrees flip angle. To study arterial neck vessels, sequences were acquired on the coronal and on the sagittal planes, centered on the cricoid. The intracranial tract of the vertebral arteries required axial sequences centered under the floor of the sella turcica. Post-processing was obtained with the maximum intensity projection technique. The coronal and sagittal sequences were rotated on the axial plane from 0 degrees to 180 degrees with 15 degrees interval, while axial sequences were rotated on the sagittal plane from 0 degrees to 180 degrees with the same interval. TR, TE and flip angle values were very important for image quality: the thinner the volumes the more effective resolution power and vessel visualization. These volumes should not exceed 1.5 mm. Axial rotations of coronal sequences from -45 degrees to +45 degrees and of sagittal sequences from 60 degrees to 120 degrees were useful for diagnosis. The intracranial tract of the vertebral arteries was clearly depicted after axial sequences and after 75 degrees and 135 degrees sagittal rotations.

Adult↗
PubMed1990

[Magnetic resonance angiography of the pulmonary artery. Preliminary considerations].

The possibility was evaluated of imaging the pulmonary artery with MR angiography. Twenty healthy volunteers were studied using 3D FT gradient-echo sequences on the coronal plane, with post-processing by the maximum intensity projection method. TE and TR remaining short, flip angles were selected to increase pulmonary artery signal in contrast with hypointense adjacent tissues and vessels. Flip angle selection allowed the optimal differentiation between pulmonary artery and aorta with 15 degree-25 degree angles (range: 110.7 to 122 for the 15 degree flip angle and 158.7 to 182.1 for the 20 degree flip angle). The sequence was obtained on the coronal plane and the following parameters were employed: TR 0.03 s, TE 10 ms, flip angle 15 degree-20 degree, slice of the total volume 100 mm with 64 partitions, 256 x 256 matrix, 1 zoom factor, 1 acquisition. The patient was positioned with the right hemithorax raised by 30 degrees to visualize the common pulmonary artery and lying on his back, face upward, to visualize the right and left pulmonary arteries. Post-processing employed axial plane rotations from -45 degrees to +45 degrees, with 5 degrees step, and from 0 degrees to 180 degrees, with 15 degrees step. Angio-MR images of the pulmonary artery allowed the visualization of its main components, up to its right and left lobar branches. The main limitation of this technique consisted in its poor spatial resolution.

Adult↗
PubMed1990

[Magnetic resonance angiography of the intracranial vessels. Technique and anatomy].

Fifty volunteers were studied by means of MR angiography of the intracranial vessels, with a 1.5 T Siemens Magnetom. The technical features of the most employed MR angiographic techniques were analyzed. The inflow technique was tested with refocused gradient-echo sequences for the FISP 3DFT flow and a dedicate coil. The study was aimed at evaluating the resolution power of each technique and at identifying the most useful rotations and angles for each chosen vessels. The acquisition volume of the gradient-echo sequence was positioned on the axial plane with sella turcica in the center. TR was set at 0.04 s, TE at 10 ms, and flip angle was 15 degrees. A 256 x 256 matrix was used, and an 80-mm acquisition volume, with 64 partitions. The chosen images were rotated on the axial and sagittal planes 0 degrees-180 degrees. The results showed that both rotation planes and their relative angles allow the visualization of all the vessels. To reduce post-processing time, with immediate availability of computer keyboard, a standardization is suggested with 0 degrees-180 degrees rotations on the axial plane, with 15 degrees interval and 0 degrees-45 degrees rotations on the sagittal plane, with 15 degrees interval. The main limitation of this method is its spatial resolution, which was 1.2 mm in rotations and acquisitions on the axial plane and 1 mm in acquisitions on the axial plane rotated on the sagittal plane.

Adult↗