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Biomedical subjects

G Simonetti

Publications and source records attributed to G Simonetti.

At least 91 records · Page 5Linked to original sources
PubMed1995

Mammography with synchrotron radiation.

PURPOSE: To determine the feasibility of using synchrotron radiation (SR) in diagnostic mammography. MATERIALS AND METHODS: Monochromatic SR of x-ray beams of selected energies of 14-20 keV were used to obtain mammograms of surgically removed breast specimens that contained tumor nodules. For comparison, conventional mammograms of the same specimens were also obtained. RESULTS: The mammograms obtained with SR had higher contrast and better resolution than did traditional mammograms and demonstrated excellent detail in all cases studied. The mean glandular doses at 17 and 18 keV were 1.56 and 0.83 mGy, respectively, which is compatible with the mean value of 1.41 mGy delivered with the conventional grid apparatus. CONCLUSION: SR mammography appears to be a promising diagnostic imaging technique.

Animals↗
PubMed1995

[Angiography with spiral computed tomography. The basic principles and clinical potentials].

Technical characteristics, acquisition modality and data representations as well as examination protocols and main clinical applications of spiral CT angiography (CTA) are described. The different methods of 2D (MPR, CPR) and 3D (SSD, MIP) data display and their advantages and limitations were investigated. We describe the examination technique representing an important tool to achieve good image quality and to make the correct diagnosis. The clinical effectiveness and the main applications in the body were studied. CTA already has a clinical role for arterial system study, while it is less indicated in the venous system because good and continuous contrast agent opacification is difficult to obtain. In our preliminary experience, CTA can be considered an effective alternative to DSA in the assessment of vascular conditions because it is easier to perform, more rapid and less invasive.

Angiography↗
PubMed1995

[Computerized tomography assessment of bone damage following injury of the anterior cruciate ligament].

An ACL tear causes an anterior subluxation of the tibial bone which rotates with its fulcrum on the medial collateral ligament; consequently, the lateral femoral condyle impacts on the external tibial plateau. The presence of a subcortical lesion of the spongiform bone in the posterior external tibial plateau is an indirect sign of an ACL tear. On MR images, traumatic changes are depicted as changes in bone marrow signals. To assess the diagnostic capabilities of CT in demonstrating the bone lesion subsequent to ACL trauma, 23 patients with positive MR exams of the knee were submitted to CT. Fifteen patients had complete ACL tears, 8 had partial tears and 20 exhibited an occult fracture of the posterior portion of the external tibial plateau. This study pointed out a significant correlation between ACL tears and changes in the spongiform structure of the posterolateral tibial plateau. Such changes are depicted not only by MRI but also by CT: the latter method is also a valuable tool to study these conditions long after the traumatic event. No more than 5 slices, 1-1.5 mm thick, acquired at the tibial plateau allowed the trabecular structure and its abnormal changes to be studied without markedly lengthening examination time.

Anterior Cruciate Ligament Injuries↗
PubMed1995

[Aneurysmal disease. Initial clinical experience with spiral computerized tomography angiography].

This study was aimed to assess the comparative capabilities of CT angiography (CTA) and DSA in diagnosing aneurysms in different sites in a series of 20 patients. Volumes were measured during intravenous contrast agent infusion and images were then edited and reformatted as 2D and 3D displays (MPR, SSD, MIP techniques). Some of the main semiologic patterns of aneurysms were considered and the diagnostic accuracy of the 3 reconstruction techniques was assessed and compared with that of axial CT and DSA. Abdominal aortic aneurysms were analyzed separately to study the involvement of main collateral vessels. The best results were obtained with MIP and MPR in the assessment of aneurysm extent and neck. MPR is the only technique which could depict the thrombus and the best technique to demonstrate the relationships between aneurysm and adjacent structures. The MIP technique depicts calcifications and is the method of choice to demonstrate the involvement of collateral vessels by abdominal aortic aneurysms. SSD permits good assessment of the neck and of the longitudinal extent of the aneurysms but is severely limited in the analysis of the other variables.

Aged↗
PubMed1995

Antifungal agents. 10. Synthesis and antifungal activities of aryl-(1H-imidazol-1-yl)-(isoquinolin-1-yl) methane derivatives.

Various aryl-(1H-imidazol-1-yl)-(isoquinolin-1-yl)methane derivatives have been synthesized and tested as antifungal agents. The new imidazoles have been obtained by the action of 1,1'-sulfinyldiimidazole on aryl-(isoquinolin-1-yl)carbinols, which have been prepared by standard procedures starting from isoquinoline. Among 44 test derivatives only a few have exhibited some antifungal activity, the most active compound (4e) being twofold less potent than miconazole, ketoconazole and bifonazole, used as standard drugs.

Antifungal Agents↗
PubMed1995

[Comparative evaluation of ultrasonography, computerized tomography, angiography and lipiodol CT in defining extent of hepatocarcinoma. A multicenter study].

The authors report the results of a multicentric trial on hepatocellular carcinoma (HCC) patients, whose lesions were confirmed with biopsy or by high (> 400 ng/ml) alpha-fetoprotein levels. The series consisted of 149 patients examined in 8 different centers and submitted to ultrasonography (US), Computed Tomography (CT) before and after contrast agent administration, angiography and Lipiodol CT. According to lesion size and number, the patients were divided with each imaging modality into three groups: a) group 1: unifocal HCC < 5 cm diameter; b) group 2: multifocal HCC with 2-3 nodules and/or tumor mass < 80 ml; c) multifocal HCC with more than 3 nodules (with total tumor mass not exceeding 40% of liver volume) or with total tumor mass > 80 ml. In 77 patients all the examinations were available for comparison. US and CT diagnosed more patients as belonging to group 1 than angiography and Lipiodol CT, while more patients were classified as groups 2 and 3 with angiography and Lipiodol CT, meaning that US and CT may understage some HCC cases (about 15%) because they show a lower number of nodules. This observation was confirmed by the direct comparison between US and Lipiodol CT (in 114 patients), CT and Lipiodol CT (in 103 patients) and angiography and Lipiodol CT (in 116 patients). US and Lipiodol CT were in disagreement in 18 cases, CT and Lipiodol CT in 16 cases and angiography and Lipiodol CT in 13 cases. In most of these cases, Lipiodol CT showed more lesions than the other techniques. The size of the undetected lesions was small, ranging few mm to 2 cm in nearly all cases. To conclude, the results of this multicentric trial show that Lipiodol CT is a fundamental tool to evaluate HCC extent. In contrast, conventional CT appeared not to add any significant piece of information and can therefore be excluded from the diagnostic protocol of HCC.

Angiography↗
PubMed1995

[Percutaneous transluminal angioplasty in the treatment of iliac stenosis. The authors' new guideline for 100 patients].

This retrospective study was carried out from January, 1990, to September, 1994, after reviewing a series of 100 patients submitted to 143 percutaneous maneuvers (PTA) for aortoiliac revascularization (PTA, PTA and stenting, PTA and bypass). This study was aimed at conforming as much as possible our patients selection criteria and the analysis of the results to the current standards adopted by the major interventional radiology and vascular surgery departments. The Fontaine and the SCVIR classification methods were used for patients selection. Long-term patency was analyzed with clinical and noninvasive diagnostic exams. The results were studied with the Life-table analysis statistical method. The patients were divided into 3 groups: the patients treated only with PTA, those treated with PTA and stenting and finally those submitted to PTA before or after a surgical bypass. The results were analyzed separately. In 95/100 patients the maneuver was technically successful and immediate clinical success was not achieved only in one of them. At the first follow-up we collected data on 87 patients; at 3 years we followed-up 30 patients, but only 5 of them had to be resubmitted to PTA (3 PTA and stenting and 2 PTA alone) because of restenosis. Secondary patency was obtained in 91% and 84% of patients at 1 year and 3 years, respectively. With the Life-table analysis, the cumulative patency rate was 95.44% at 36 months. Few complications were observed (11/100 patients), especially considering that they were classified as "severe" in 3 cases only. To conclude, our results prove PTA to be a highly effective tool in the aortoiliac arteries, whose low mortality and complication rates suggest the use of this percutaneous procedure.

Aged↗
PubMed1994

A double-blind comparative study of the safety and efficacy of iomeprol in renal intra-arterial digital subtraction angiography.

This randomised, double-blind, parallel group study was to compare the safety, tolerance and diagnostic efficacy of iomeprol and iopamidol, both at an iodine concentration of 150 mgI/ml, in 40 patients with arterial hypertension who required renal intra-arterial digital subtraction angiography (IA-DSA) for suspected renovascular stenosis. All patients underwent extensive pre- and post-contrast clinical, instrumental and laboratory controls for safety assessments. The tolerance to the test contrast media was evaluated in terms of discomfort associated with the injection of the test compounds. Image quality was prospectively graded by two independent readers according to a five-point scale as follows: 1, insufficient; 2, sufficient; 3, good; 4, excellent; E, excessive. The quality of vascular opacification in the region of interest was rated as diagnostic in 87.8% of radiographs obtained in the iomeprol group and in 84.5% in the iopamidol group, without significant differences between the two study groups. The results of angiography were always useful for subsequent patient management. The procedure was always well tolerated. There were no clinically significant changes in vital signs, ECG and laboratory parameters during the study in both groups. The results of our study show that iomeprol 150 mgI/ml, and iopamidol 150 mgI/ml are equally effective, well tolerated and safe contrast agents when used for IA-DSA.

Adult↗
PubMed1994

Advances in interventional radiology in oncology.

Interventional radiology (IR) includes all procedures performed percutaneously under US, fluoroscopy, CT or DSA guidance by a radiologist to obtain diagnostic and therapeutic achievements. According to the pathology under examination, these procedures may be applied alone, as a definite therapeutic tool, or together with other traditional techniques permitting an easier and more successful application. In this report the authors discuss briefly the IR possibilities in many oncological branches.

Chemoembolization, Therapeutic↗
PubMed1994

Halifax interlaminar clamps for posterior atlanto-axial arthrodesis with spinal fusion by "H" bone+graft.

The use of Halifax interlaminar clamps in posterior arthrodesis for atlanto-axial instabilities has recently been reported. The four Anderson II fractures submitted were surgically treated by posterior arthrodesis with Halifax clamps and bilateral "H" shaped bone-grafts obtained from the iliac crest. Only in the first case--initially treated without fusion--a review of the system became necessary due to the loosening of one clamp. No post-operative neurological complications appeared and non malunion or nonunion occurred at follow-up. Posterior arthrodesis with Halifax clamps does not involve any complication connected with the use of metal wire and the association of posterior fusion by lateral "H" shaped bone grafts ensures a stable and physiological reduction of dens fractures and atlanto-axial luxations/subluxations often associated.

Adult↗
PubMed1994

[Magnetic resonance imaging in denervated muscle. A preliminary study].

Ten patients with various forms of peripheral neuropathy and spinal radiculopathy were examined with MRI using a low-field permanent magnet (0.2 T) and spin echo (SE)/inversion recovery (IR) sequences, with an adequate inversion time to suppress healthy muscle signal. In acute denervation MR sensitivity was low on both sequences; in subacute denervation the damaged muscle was more intense than the healthy muscle only on IR sequences. MRI adequately depicted fatty infiltration in chronic denervation. In conclusion, MRI is a promising tool for mapping and noninvasively monitoring denervated motor units in skeletal muscles, whose role is currently complementary to that of electromyography.

Acute Disease↗
PubMed1994

[An introduction to fast and ultrafast sequences in magnetic resonance].

The main limitations of magnetic resonance imaging (MRI) are due to the long acquisition time needed for data sampling. Fast and ultrafast sequences, thanks to progress in hardware and software technology, allow the acquisition times to be dramatically reduced. Such improvements will definitely increase MR capabilities and make MRI a fast and dynamic technique no longer depending on patients' cooperation and limited by patients' conditions--e.g., trauma, pediatric, or claustrophobic patients--or even by the anatomic features of the region of interest. The latest experimental studies are aimed at increasing the clinical applications and the perspectives of clinical MRI and at such ambitious goals as MR-fluoroscopy, interventional MRI, total body examination in less than one minute and functional MRI. In this paper the technical principles and the main indications of this new kind of sequences are reported, with a special emphasis on Gradient-Echo (GE), Turbo Spin-Echo (turbo SE) or Fast Spin-Echo (fast SE), Turbo FLASH and Echo Planar (EP) sequence. A smaller flip angle (FA) and the substitution of the 180 degrees RF pulse with a gradient reversal are the main differences of GE from SE sequences. From GE sequences, several fast sequences are derived, such as angiographic and turbo FLASH sequences. The latter, thanks to 180 degrees preinversion RF pulse, using idoneous inversion times (IT), provide flexible contrast. Turbo SE sequences, which are directly derived from conventional SE sequence, allow the acquisition time to be markedly shortened, by acquiring several Fourier lines of K-space for each TR. The repetition of several 180 degrees pulses following the excitatory 90 degrees RF pulse does the trick through the creation of multiple echoes for a single TR. EP sequences are the fastest ones currently available: with them, an image can be acquired in 30-100 ms. However, the limited availability of the relative hardware and the need of both quality implementation and the definition of clinical indications are major obstacles to the widespread use of these sequences. The SE T2-weighted sequence, the main responsible for the long examination time, will be replaced soon. Further implementation of these sequences will make MRI a fast, flexible and adaptable method to any exam and patient disability.

Echo-Planar Imaging↗
PubMed1994

Antifungal agents. VIII. Synthesis and antifungal activities of bipyrryl analogues of bifonazole.

Various bipyrryl analogues of bifonazole were synthesized starting from aryl-3-pyrryl-1-imidazolylmethanes. The introduction of a second pyrryl portion was performed by linking an acrylate moiety at 1-position of the pyrrole ring and then by treatment with TosMIC. The bipyrryl esters were hydrolyzed and decarboxylated to afford the required imidazoles. All new imidazole derivatives were tested against Candida albicans and Candida spp using as standard controls miconazole, bifonazole and ketoconazole.

Antifungal Agents↗
PubMed1993

Palliative treatment of extrahepatic bile ducts tumors.

Extrahepatic bile duct (EHBD) tumors often become symptomatic in an advanced stage when curative resection is seldom possible. In a group of 111 patients, 7 (6.3%) received no treatment, 32 (28.8%) underwent non-operative biliary drainage (NOD), and 72 (64.8%) underwent surgical exploration. Radical resection was possible in only 25 cases (34.7%); 14 patients (19.4%) underwent a biliary digestive bypass (BDB), 15 (20.8%) received a transtumoral biliary prosthesis (TBP), and 18 (25.0%) an external biliary drainage (EBD). Average survival rates were: 6.5 months after BDB, 4.0 months after TBP, and 2.8 months after EBD. In a second group of 2,066 patients with primary and secondary malignant obstruction of the upper EHBD, treated with the insertion of a Carey-Coons transhepatic transtumoral biliary prosthesis, the average survival was 4.3 months. The early morbidity rate was 0.6%. Obstruction of the prosthesis occurred in 91 patients (4.4%), and the late morbidity rate was 3.6%. Although EHBD tumor treatment results are generally poor, surgical exploration should be performed in all patients with acceptable surgical risk, and without evidence of disseminated disease. When resection of the tumor is not feasible, we favor the use of a BDB or of a biliary prosthesis over that of an external drainage. In poor risk cases or cases with evidence of disseminated disease, we prefer the placement of an internal prosthesis (PTBD or endoscopic.

Adult↗