Publications (12)17.13 Total impact
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Article: In vitro investigation of poor cerebrospinal fluid suppression on fluid-attenuated inversion recovery images in the presence of a gadolinium-based contrast agent.
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ABSTRACT: Cerebrospinal fluid (CSF) enhancement on fluid-attenuated inversion recovery (FLAIR) images obtained post-gadolinium (Gd)-based agent injection is described in stroke and multiple sclerosis. Blood brain barrier (BBB) disruption with contrast agent extravasation into CSF shortens T(1) relaxation times, reducing fluid suppression. Reduced fluid suppression on FLAIR images was investigated in vitro in the presence of escalating gadopentetate dimeglumine (Gd-DTPA) concentrations mixed with artificial CSF. Low Gd-DTPA concentrations impair fluid suppression of FLAIR imaging in association with progressively reduced T(1) values. At higher concentrations, the prevalent T(2) shortening effect can explain signal intensity (SI) reduction. Post-Gd FLAIR may be useful in detecting subtle BBB leakage.Magnetic Resonance in Medicine 08/2008; 60(1):220-3. · 2.96 Impact Factor -
Article: In vitro investigation of poor cerebrospinal fluid suppression on fluid‐attenuated inversion recovery images in the presence of a gadolinium‐based contrast agent
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ABSTRACT: Cerebrospinal fluid (CSF) enhancement on fluid-attenuated inversion recovery (FLAIR) images obtained post-gadolinium (Gd)-based agent injection is described in stroke and multiple sclerosis. Blood brain barrier (BBB) disruption with contrast agent extravasation into CSF shortens T1 relaxation times, reducing fluid suppression. Reduced fluid suppression on FLAIR images was investigated in vitro in the presence of escalating gadopentetate dimeglumine (Gd-DTPA) concentrations mixed with artificial CSF. Low Gd-DTPA concentrations impair fluid suppression of FLAIR imaging in association with progressively reduced T1 values. At higher concentrations, the prevalent T2 shortening effect can explain signal intensity (SI) reduction. Post-Gd FLAIR may be useful in detecting subtle BBB leakage. Magn Reson Med 60:220–223, 2008. © 2008 Wiley-Liss, Inc.Magnetic Resonance in Medicine 06/2008; 60(1):220 - 223. · 2.96 Impact Factor -
Article: Supervised automatic procedure to identify new lesions in brain MR longitudinal studies of patients with multiple sclerosis.
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ABSTRACT: Identification of new enhancing lesions is a major endpoint of longitudinal brain magnetic resonance (MR) studies of multiple sclerosis (MS). To date, this is a visual, time-consuming procedure. We present here a supervised automated procedure (SAP) aimed at reducing the time needed to identify new MS enhancing lesions. The SAP uses an algorithm including Cartesian coordinates of the lesions to be compared, their area and a constant (k). The procedure was validated for enhancing lesions on T1-weighted spin-echo images after intravenous administration of 0.1 mmol/kg of paramagnetic contrast agent, randomly selected from a dataset of a longitudinal MR study on ten relapsing-remitting MS patients followed for 2-5 years. During the validation session, two readers decided by consensus whether two lesions, present on the same slice of two examinations performed on subsequent dates, were the same or not. In this way, k was calibrated to obtain the same result from both visual inspection and automatic algorithm output. After evaluating of 25+/-5 (mean+/-standard deviation) lesions in each of ten different sessions with correction of k value, the k value became a stable value (0.45+/-0.05). Once the suitable value of k was found, SAP was able to identify new enhancing lesions, avoiding visual inspection, which is usually a lengthy procedure.La radiologia medica 04/2008; 113(2):300-6. · 1.44 Impact Factor -
Article: Stochastic resonance in the human visual system - A fMRI study
RIVISTA DI NEURORADIOLOGIA. 01/2000; 13(1):119-123. -
Article: fMRI studies of visual cortical activity during noise stimulation
NEUROCOMPUTING. 01/1999; 26-7:511-516. -
Chapter: fMRI studies of visual cortical activity during noise stimulation
01/1999: pages 511-516; -
Article: fMRI studies of visual cortical activity during noise stimulation.
Neurocomputing. 01/1999; 26-27:511-516. -
Article: Effect of copolymer-1 on serial gadolinium-enhanced MRI in relapsing remitting multiple sclerosis.
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ABSTRACT: We examined the effect of Copolymer-1 (Cop1) on magnetic resonance (MR) imaging changes in 10 patients with relapsing-remitting multiple sclerosis (RRMS). Monthly gadolinium (Gd)-enhanced MR imaging was performed for 9 to 27 months in the pretreatment period followed by 10 to 14 additional months during Cop1 treatment. MR images were evaluated by two radiologists (F.S. and R.C.P.) masked to the scan date. We found a 57% decrease in the frequency of new Gd-enhancing lesions and in the mean area/month of new Gd-enhancing lesions in the Cop1 treatment period compared with the pretreatment period (0.92 versus 2.20 lesions per month and 22 mm2 versus 43 mm2 area/month; p = 0.1, Wilcoxon signed rank test). Percentage change in lesion load area on T2-weighted images showed a decrease in the accumulation of lesion area during treatment, which was significant for the patient group with a longer pretreatment period (p = 0.05, Friedman test). These results demonstrate a reduction in the number of new Gd-enhancing lesions and in the lesion load during Cop1 treatment compared with the preceding period without therapy and are suggestive of an effect of Cop1 on MR abnormalities observed in multiple sclerosis.Neurology 05/1998; 50(4):1127-33. · 8.31 Impact Factor -
Article: [Magnetic resonance spectroscopy: what is its role in cardiography?].
Cardiologia (Rome, Italy) 05/1998; 43(4):347-55. -
Article: The choice of radiographic film-screen systems: quality evaluation and purchasing specifications drafting. Report on A.I.F.B. Working Group activity.
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ABSTRACT: The comparative evaluation of radiographic screen-film systems presents several problems from both the theoretical and the experimental points of view. From the theoretical point of view the main difficulties are related to the choice of the parameters best suited to express the "overall quality" of a system. This quantity is expressed as a product of image quality index and system sensitivity. As image quality index we assumed the signal-to-noise power ratio: this index depends in an explicit way on contrast, resolution and noise of the system. From the experimental point of view the main problem is that to measure some basic quantities, sophisticated and expensive equipment, like computer-controlled microdensitometers, is generally required. In this paper, we report the Italian Association of Biomedical Physicists Task group suggestions for measuring the basic physical parameters (with particular reference to the use of cost-effective equipment and for purchasing specification drafting). Using synthetic quality indices, the evaluation criteria of radiographic materials are directly derived from the general theory of radiographic image perception.La radiologia medica 06/1993; 85(5):662-7. · 1.44 Impact Factor -
Article: Magnetic resonance spectroscopy of ischemic heart disease.
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ABSTRACT: An overview of the basic knowledge necessary to understand the procedure of Magnetic Resonance Spectroscopy of the myocardium and its most significant applications in the study of ischemic heart disease, is presented, with reference to the personal experience. The chemical shift phenomenon, the main techniques of spectroscopic localization and the general aspects of myocardial 31P and 1H Magnetic Resonance Spectroscopy, including proton decoupling and magnetization transfer, are illustrated. Postprocessing techniques before and after Fourier transform are mentioned. 31P Magnetic Resonance Spectroscopy allows the noninvasive assessment of the metabolism of high energy phosphates, PCr/ATP ratio in particular, in the in vivo myocardial tissue with significant applications in the diagnostic approach to ischemic patients with the support of provocative tests (dobutamine). 1H Magnetic Resonance Spectroscopy allows similar evaluations based on the peak of total creatinine.Rays 24(1):149-64. -
Article: fMRI studies of visual cortical activity during noise stimulation
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ABSTRACT: Psychophysics experiments on the human visual system have established that the sensitivity for the detection of fine detail in noise contaminated images can be quantitatively and repeatably measured using stochastic resonance as a tool. Optimal noise results in maximal sensitivity. Does this mean simply that the retina is averaging out the noise, or instead is the visual cortex involved in some level of computation? We report results of functional magnetic resonance imaging experiments which indicate the latter.Neurocomputing.
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- La radiologia medica (2)
- Neurology (1)
- Rays (1)
- Cardiologia (Rome, Italy) (1)
- Magnetic Resonance in Medicine (1)
Institutions
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2008
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Università degli Studi di Genova
Genova, Liguria, Italy -
Azienda Ospedaliera Universitaria San Martino di Genova
Genova, Liguria, Italy
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