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Biomedical subjects

G Simonetti

Publications and source records attributed to G Simonetti.

At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

[Non-invasive assessment of epiaortic vessels. Comparison of magnetic resonance angiography with gadolinium, spiral computerized tomography angiography, and digital angiography].

PURPOSE: The aim of the study was to compare gadolinium-enhanced MRA (Gd-MRA), Computed Tomography angiography (CTA) and digital subtraction angiography (DSA) in the evaluation of carotid stenosis. MATERIAL AND METHODS: Thirty patients with US-proven internal carotid artery stenosis over 50%, underwent Gd-MRA, CTA and DSA. Gd-MRA was acquired using the keyhole technique. RESULTS: The overall agreement was 90% for Gd-MRA and 93% for CTA. Gd-MRA and CTA overestimated 5 and 4 cases of mild stenosis and 1 case each of moderate stenosis, respectively. Gd-MRA better delineated ulcerated plaques, tandem lesions and pseudo-occlusions. DISCUSSION AND CONCLUSIONS: Because of the high speed acquisition breath-hold is no longer necessary for Gd-MRA and more delayed phases were analysed when necessary. The main limitation of Gd-MRA was represented by insufficient volume coverage that allowed the visualisation of supraaortic vessels from the arch only in 57% of the cases. Calcified plaques were very well detected by CTA and not by Gd-MRA. In our experience Gd-MRA represents the second step non invasive tool in patients with US-proven carotid stenosis. This leads to avoid conventional angiography in most cases.

Angiography, Digital Subtraction↗
PubMedDate not supplied

Diffusion and perfusion MR imaging in cases of Alzheimer's disease: correlations with cortical atrophy and lesion load.

BACKGROUND AND PURPOSE: Perfusion and diffusion-weighted MR imaging are powerful new imaging techniques for evaluating tissue pathophysiology in association with many neurologic disorders, such as neurodegenerative diseases. The purpose of our study was to evaluate the sensitivity and specificity of dynamic susceptibility contrast-enhanced MR imaging and diffusion-weighted MR imaging in cases of Alzheimer's disease and to assess the role of atrophy in the quantification of cortical perfusion. METHODS: Thirty-nine participants were studied: 18 patients with moderate cognitive impairment with probable Alzheimer's disease, 16 patients with mild impairment with possible or probable Alzheimer's disease, and 15 group-matched elderly healthy comparison volunteers. Relative values of temporoparietal, sensorimotor, and hippocampal regional cerebral blood volume (rCBV) were measured as a percentage of cerebellar rCBV, and group classification was assessed with logistic regression. Brain atrophy was used as a covariate to assess its role in rCBV quantification. Regions of interest placed on orientation-independent apparent diffusion coefficient maps allowed the calculation of apparent diffusion coefficient values and relative anisotropic indices of the head of the caudate nuclei, thalamus, parietal, frontal, and hippocampal cortices bilaterally, genu and splenium of corpus callosum, and anterior and posterior white matter in patients with Alzheimer's disease and in control volunteers. RESULTS: Temporoparietal rCBV ratios were reduced bilaterally in the patients with Alzheimer's disease. Sensitivity was 91% in moderately affected patients with Alzheimer's disease and 90% in patients with mild cases. Specificity was 87% in healthy comparison volunteers. Lower values of sensitivity and specificity were obtained for sensorimotor (73%, 50%, and 67%, respectively) and hippocampal cortices (80%, 80%, and 65%, respectively). Using brain atrophy as a covariate, patients with Alzheimer's disease still showed a statistically significant reduction of rCBV compared with control volunteers. Diffusion-weighted MR imaging analysis only showed a trend, with no statistic significance, of reduction of anisotropy in posterior white matter. CONCLUSION: Dynamic susceptibility contrast-enhanced MR imaging of rCBV may be an alternative to nuclear medicine imaging for the evaluation of patients with Alzheimer's disease. When brain atrophy is used as a covariate, differences in rCBV still persist between patients with Alzheimer's disease and control volunteers, suggesting that perfusion impairment is unrelated to atrophy. No significant results for either white or gray matter were obtained using diffusion-weighted MR imaging.

Aged↗
PubMedDate not supplied

Cerebral hemodynamics in asymptomatic patients with internal carotid artery occlusion: a dynamic susceptibility contrast MR and transcranial Doppler study.

BACKGROUND AND PURPOSE: Perfusion imaging with dynamic susceptibility contrast MR imaging (DSC-MRI) has been used to evaluate hemodynamic status in patients with symptomatic occlusive cerebrovascular disease. The aim of the present study was to determine the hemodynamic changes occurring in asymptomatic patients with unilateral internal carotid artery (ICA) occlusion by use of DSC-MRI with transcranial Doppler (TCD) measurement of the breath-holding index (BHI). METHODS: Nine patients with asymptomatic unilateral ICA occlusion underwent DSC-MRI and TCD examination. One patient was excluded from final analysis because of severe movement artifacts. On a separate workstation, regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and regional mean time to peak (rMTT) were calculated on the basis of signal decay rate during the passage of gadolinium bolus through the sampled volume in the territory of the middle cerebral artery. TCD-BHI was calculated in all patients. Six healthy subjects underwent the same MR protocol as the patients. RESULTS: Compared with control subjects, patients with unilateral ICA occlusions had hemodynamic changes in the ipsilateral hemisphere: rCBF was significantly lower than in controls (P <.01), and r MTT was significantly increased in both white (WM) and gray matter (GM) in the affected side (WM: P <.01; GM: P <.05). No statistically significant difference in rCBV was found in the group of patients (occluded versus contralateral, P <.1) or between the patient and control groups (occluded side versus controls, P <.1). The correlation of rCBV and BHI showed a strong relation of the two variables, showing a decrease of the latter when the former increased. CONCLUSION: DSC-MRI is a valuable tool for measuring hemodynamic changes in the presence of carotid disease with hemodynamic impairment. In our opinion, hemodynamic changes and efficiency of collateral pathways can be evaluated in occlusive carotid disease by using paired measurement of BHI and DSC-MRI. In the patient group, MR-determined rCBV and TCD-determined BHI showed a significant inverse correlation, suggesting similar significance of the two indices.

Angiography, Digital Subtraction↗
PubMedDate not supplied

Radioguided-surgery of early breast lesions.

BACKGROUND: Radioguided-surgery has been recently proposed in patients with clinically occult breast lesions. This study aimed to evaluate the feasibility of correctly locating and eradicating, by a single intralesional injection of a radiotracer, any breast lesion and, in the case of malignancy, to perform simultaneous sentinel lymph node (SLN) biopsy procedure. PATIENTS AND METHODS: Sixty-three women with early breast lesions were enrolled: 42 were invasive carcinomas, 16 in situ ductal carcinomas (DCIS) and 5 fibroadenomas. RESULTS: Scintigraphic images clearly identified the lesions in all patients while SLN/s were evident in 88% of them. At surgery all the breast lesions were easily radiolocalized and eradicated with minimum surgical trauma and, for those patients with invasive carcinomas, the SLN technique was performed in 86% of them. No skip metastases were found. CONCLUSION: A single intralesional administration of radiotracer is an easy and reliable procedure to simultaneously locate and remove both the non-palpable breast lesion and the SLN when primary malignancy was intraoperatively confirmed.

Adult↗
PubMedDate not supplied

[Ultrasound hysterosalpingography with levovist in the diagnosis of tubaric patency].

UNLABELLED: PURPOSE AIM: To asses the diagnostic value of hysterosalpingo-contrast sonography (HyCoSy) with Levovist(R) as alternative to conventional hysterosalpingography (HSG) in the study of infertility. MATERIAL AND METHODS: From September 1988 to March 2000 we evaluated 120 patients with a history of infertility. Thirty patients underwent both HyCoSy and HSG. HyCoSy was performed in the pre-ovulatory phase of mestrual cycle. The tecnique was the same for both examinations. After administering 15 ml contrast medium, we visualized the endometrial cavity, the flow of the contrast medium along the fallopian tubes and its passage into the peritoneum. RESULTS: In all cases Color-Power Doppler allowed visualization of the uterine cavity and of the spilling of the contrast medium into the peritoneum, yielding information on tube patency that was comparable to that obtained by conventional HSG. In 28 cases (93%) we obtained optimal visualization of the contrast medium at the level of both the endometrial cavity and the fallopian tubes. HyCoSy proved to be superior to conventional HSG in evaluating adjacent myometrial structures, adnexa and degree of follicular maturation, equal to HSG in visualizing the passage of the contrast medium into the peritoneum but inferior to HSG in imaging the fallopian tubes owing to their tortuosity. DISCUSSION AND CONCLUSIONS: The absence of ionising radiation makes HyCoSy a possible first choice examination in the evaluation of fallopian tube pathology. Conventional HSG should be kept for doubtful cases or for surgical procedures to correct mono- or bilateral obstruction.

Adult↗
PubMedDate not supplied

[Treatment of intermetatarsal neuromas with alcohol injection under US guide].

PURPOSE: The cause of intermetatarsal neuromas is unclear; the pathogenesis is, most likely, a mechanically induced degenerative neuropathy or an entrapment of the intermetatarsal nerve under the transverse intermetatarsal ligament. Treatment of intermetatarsal neuromas includes very simple methods, such as changing shoe styles, or more complex conservative treatments such as orthotic devices and steroid injections until surgical therapy. This study aimed to evaluate the neuroma's intralesional treatment with alcohol sclerosing injection as a viable alternative to steroid injections or surgery in persisting symptoms. MATERIAL AND METHODS: 23 patients with clinical symptoms of intermetatarsal neuroma and who had not undergone other treatments were treated with 30% alcohol applied under US guide. Each patient received from 3 to 7 applications at 7 to 10 day intervals. RESULTS: We performed 3 applications in 17 patients, 5 in 5 patients and 7 in 1 patient for a total of 83 applications with a technical success of 100%. A complete resolution of all symptoms was achieved in 91% of the patients. CONCLUSION: Alcohol sclerosing intralesional treatment under US guide is a viable alternative to conservative or surgery treatments in patients with intermetatarsal neuromas.

Adult↗
PubMedDate not supplied

Multidetector row CT coronary angiography: technique and preliminary experience.

PURPOSE: To report our preliminary experience with multi-slice spiral CT coronary angiography of the coronary arteries. MATERIALS AND METHODS: 50 volunteers (mean age 61 years, range 45-72) with baseline heart rates below 70 bpm underwent multi-detector row CT coronary angiography (GE Light Speed Plus, 140 kVp, 270 mA, 1.25-mm collimation, 0.5-second rotation time, high quality pitch) with retrospective ECG gating after receiving 140-150 ml of iodinated contrast medium (Iopamiro 300 mg-dl, Bracco, Italy) at a flow rate of 4 ml/sec. Three of the 50 patients had previously undergone coronary procedures (1 anterior descending artery stent, 1 left circumflex artery stent and 1 anterior descending artery percutaneous angioplasty) and three were undergoing follow-up examinations after by-pass surgery. The remaining 44 patients were asymptomatic and had no history of coronary artery disease. All CT angiograms were back-reconstructed from 20 to 80% of the diastolic cycle with 10% increments to establish the phase with fewer "stair-step" motion artefacts for each artery. Patients with heart rates above 70 bpm were administered beta-blockers during the five days preceding the examination in doses appropriate for the patient's clinical characteristics. RESULTS: The CT room occupation time ranged from 25 to 35 minutes (mean time 27') and the post-processing time from 30 to 60 minutes (mean time 40'). The left anterior descending artery was best visualised in middle diastole (70% of cardiac cycle), the circumflex artery at 60% of the cardiac cycle, and the right coronary artery at 40%. Out of 132 arteries, 19 (14.4%) were considered non-assessable due to "stair-step" motion artefacts, whereas 2 (1.5%) were only partially visualised owing to the presence of extensive wall calcifications. Among the 113 assessable arteries, we observed: 72 normal coronary arteries without stenosis or wall calcifications (54.5%); 28 arteries with minimal wall irregularities and stenoses below 50% (21.2%); 7 stenoses >50% involving the right coronary artery (no. 2), the anterior descending arteries (no. 4) and the left circumflex artery (no. 1) (5.3%). In the remaining 6 patients, optimal visualisation of the stents and venous and arterial surgical by-passes was obtained. CONCLUSIONS: Although further larger-scale studies are required to compare MSCT coronary angiography with CT coronary angiography, the application of MSCT technology to the study of the coronary arteries is a promising technique with a good potential for use in routine clinical practice. In selected patients (with baseline heart rates <70 bpm, or after beta-blocker therapy) it is able to provide very interesting results and could be used as a method of choice for following patients after interventional procedures or as a mass-screening tool to select patients to be referred for coronary angiography.

Aged↗
PubMedDate not supplied

[Interventional radiology in the treatment of acute and chronic mesenteric ischemia].

Radiologic revascularization procedures--i.e., percutaneous transluminal angioplasty (PTA) and fibrinolysis--are a valuable alternative to surgery in the treatment of stenoses and occlusions of the visceral vessels, that is the celiac tripod and the superior and inferior mesenteric arteries. We treated 32 patients, 10 of them with acute mesenteric ischemia and 22 with chronic mesenteric ischemia and clinical signs of angina abdominis. Grüntzig or pre-shaped Cobra or Simmons balloons were employed (diameter: 5-7 mm, with variable length) when PTA was performed. Urokinase or rtPA was employed for fibrinolysis. In 3 cases acute mesenteric ischemia was not occlusive and could be successfully treated with papaverine infusion. In 7 cases, acute mesenteric ischemia was occlusive: in 5 of these patients it was successfully treated by PTA and/or fibrinolysis. Our results were positive in 80% of the cases, with remission of clinical signs in 4 of 5 patients treated for acute mesenteric ischemia. In 22 patients with chronic mesenteric ischemia, 26 stenotic occlusions were observed at angiography and 22 were treated with PTA, which was technically successful in 21 instances (early success rate: 85-95%). At 24 months, 10% of restenosis was observed. In our experience, PTA of the visceral district, possibly preceded by loco-regional infusion of fibrinolytic drugs, can be widely applied and yields excellent therapeutic results.

Acute Disease↗
PubMedDate not supplied

Incidence and clinical study of ectopic erythropoiesis in adult patients with thalassemia intermedia.

We carried out total body computerized tomography (CT) studies and examined the retrospective clinical data of 29 adult patients with thalassemia intermedia (TI) to evaluate the incidence, features and pathogenesis of ectopic erythropoiesis (EE), located chiefly at the paravertebral gutters in the thorax, was present in 65.5% of the patients; 15% of them had severe clinical complications. We found a clear relationship between EE development and early presentation age of thalassemia, splenectomy and the presence of 100% fetal hemoglobin. The frequent occurrence of EE suggests that CT screening of patients with thalassemia intermedia should be mandatory. We also recommend radiotherapy as a preventive measure for the clinical complications of thalassemic patients with EE.

Adolescent↗
PubMedDate not supplied

Computed tomography detection of gastrointestinal neoplasms.

Gastrointestinal (GI) tract neoplasms can be detected, evaluated and staged by computed tomography (CT), especially from high-resolution examinations, but routine CT scanning may occasionally discover GI neoplasms in patients with non-specific symptoms. We therefore evaluated the sensitivity and main signs of CT examinations resulting from routine sessions. In 46 out of 1560 patients who underwent abdominal CT, it was possible to obtain a diagnosis of primitive gastric or colo-rectal tumour by means of barium X-ray and/or endoscopy. The sensitivity rate of CT obtained from the present study was 86% in gastric tumours and 87% in colonic tumours. In gastric lymphoma, infiltrating carcinoma of stomach and rectal carcinoma, the sensitivity rate was 100%. The CT diagnosis of GI neoplasms was based on diffuse or local thickening of the gut on a solid dishomogenous mass showing contrast enhancement. The prevalence of various patterns depends on site of origin and on macroscopic features of the neoplasia. In conclusion the results suggest that abdominal CT, even if performed with a method not specifically devoted to GI tract, has high sensitivity rates and then a high probability of detecting GI neoplasms when unsuspected at time of the examination. In our series 11% of GI neoplasms were initially diagnosed by routine CT examination.

Adult↗
PubMedDate not supplied

Postoperative CSF problems after spinal and lumbar surgery. General review.

Although the dura is frequently traumatized in surgery, and during lumbar punctures, it is surprising that the "CSF problem" is a rare complication in the surgical treatment for herniated intervertebral disc (0.1%); and exceptionally rare at cervical or dorsal level. In the upright position the CSF pressure at the site of the potential leak is greater in the lumbar region, lumbar operations are more frequently performed than cervical, and, perhaps, also because cervical operations are performed by fewer surgeons with greater specific experience. The purpose of this work is to describe the etiopathology, the symptomatology, the diagnosis and treatment of early and delayed CSF problems.

Cerebrospinal Fluid↗
PubMedDate not supplied

Collet-Sicard syndrome caused by a coiling of the internal carotid artery.

A Collet-Sicard syndrome was observed in a 53-year-old patient with a coiling of the left internal carotid artery just below the skull base. Although impairment of cranial nerves by tortuous vessel compression has frequently been reported, a combined palsy of the last four cranial nerves related to such a mechanism has never been described before.

Carotid Artery, Internal↗
PubMedDate not supplied

[Antimicrobial characteristics of a tincture of dequalinium chloride].

Dequalinium is a quaternary ammonium salt. From about 30 years Dequalinium (D.C.) was used in the treatment of the initial respiratory organs infections. It can be given orally and topically yet it cannot be given systemically cause its probable systemic toxicity. D.C. has a wide range of antimicrobial activity that is extended to Gram positive, Gram negative bacteria, protozoa and yeast. Its mechanism of action is directed to the cytoplasmatic membrane where D.C. caused its damage and consequently release of cellular components. Our study has been evaluated the antimicrobial activity of D.C. both as commercial product that pure substance. We tested 27 Gram positive bacteria, 49 Gram negative bacteria, 83 strains of fungi, we also tested the antimicrobial activity of D.C. commercial product and pure substance against 8 strains of protozoa; Trichomonas vaginalis. The antimicrobial activity was estimated in some experimental conditions, (cultural and no cultural conditions); in these experiments we can observed that the commercial product presents higher activity than pure substance. In cultural condition commercial product presents antimicrobial activity against Gram positive and negative bacteria and yeast; its interesting to evaluate that bacteria, that are resistant to the common antimicrobial agents were inhibited by D.C. tinture and pure substances. Our data exhibit that serum didn't interfere until the 2% concentration with the antimicrobial activity of D.C., moreover this antimicrobial activity is not influenced by the inoculum size until 10(5) cell/ml. D.C. presents higher activity at alkaline pH than acid pH but strains of C. albicans were killed by D.C. at acid pH. In no cultural conditions D.C. has demonstrated a rapid antimicrobial activity in short contact time (15 minute); the cells of some microorganisms were killed in 60 minutes. Against mycelial form, the commercial product demonstrates good activity higher than pure substance. The activity of D.C. against the formation of germ-tube from blastospores of C. albicans in N-acetyl-glucosamine solution (no culture medium) was markedly high; this is very important because in C. albicans the germ-tube production and yeast-mycelial conversion are prominent for pathogenicity and resistance to host defences. Our data demonstrate the good activity of D.C. against Trichomonas vaginalis; we can also observed that the antimicrobial activity of commercial product is higher than pure substance.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗