A. Maiorana

Phenylketonuria: white-matter changes assessed by 3.0-T magnetic resonance (MR) imaging, MR spectroscopy and MR diffusion

PurposeThis study evaluated the sensitivity of a 3.0-Tesla (T) magnetic resonance imaging (MRI) in measuring cerebral phenylalanine using proton magnetic resonance spectroscopy and in assessing MR-documented white-matter changes by means of diffusion studies (diffusion-weighted imaging, apparent diffusion coefficient map; diffusion tensor imaging) in patients with phenylketonuria.Materials and methodsThirty-two patients with the classical clinical and biochemical deficits of phenylketonuria underwent biochemical (blood phenylalanine), genotypic (phenylalanine hydroxylase gene) and radiological investigation by means of MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging with a 3.0-T scanner.ResultsPeriventricular and subcortical white-matter changes were detected on all MR scans. In 29/32 patients, proton magnetic resonance spectroscopy easily documented abnormal signal elevation at 7.36 ppm, corresponding to phenylalanine, despite its low concentration. Phenylalanine signal amplitude relative to the creatine/phosphocreatine signal increased linearly with blood phenylalanine values (r 0.7067; p<0.001). Diffusion MRI demonstrated hyperintensity in the areas exhibiting MRI changes as well as decreased apparent diffusion coefficient values, but fractional anisotropy indices were normal.ConclusionsThe high signal, together with better spectral, spatial, contrast and temporal resolution, makes the 3.0-T MR the most suitable technique in the study of the phenylketonuria. In particular, the multimodal approach with MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging can provide more information than previous studies performed with low-field systems.RiassuntoObiettivoValutare in pazienti con fenilchetonuria la sensibilità di un sistema di risonanza magnetica (RM) a 3,0 Tesla (T) nel misurare la fenilalanina cerebrale con la spettroscopia protonica e nel documentare le alterazioni della sostanza bianca rilevate con lo studio RM di base utilizzando gli studi di diffusione (imaging pesato in diffusione, mappa del coefficiente di diffusione apparente, imaging del tensore).Materiali e metodiTrentadue pazienti con il deficit clinico e biochimico classico di fenilchetonuria sono stati sottoposti ad uno studio biochimico (livelli della fenilalanina cerebrale), genotipico (gene fenilalanina idrossilasi) e radiologico mediante uno studio RM di base, di spettroscopia e di diffusione con apparecchiatura a 3,0 T.RisultatiIn tutte le immagini RM morfologiche sono state rilevate alterazioni della sostanza bianca periventricolari e sottocorticali. In 29 pazienti su 32 la spettroscopia protonica ha rilevato facilmente un picco anomalo a 7,36 ppm corrispondente alla fenilalanina nonostante la sua bassa concentrazione. Ls’ampiezza del segnale della fenilalanina relativo al rapporto creatina/fosfocreatina incrementa linearmente con la fenilalanina ematica (r=0,7067; p<0,001). Lo studio di diffusione ha evidenziato iperintensità focali nelle aree di alterato segnale documentate con lo studio RM di base, valori di coefficiente di diffusione apparente ridotto e indici di anisotropia frazionata normale.ConclusioniLs’alto segnale assieme alla maggiore risoluzione spettrale, spaziale, di contrasto e temporale rende il sistema 3,0 T ideale per lo studio della fenilchetonuria. In particolare ls’approccio multimodale con imaging RM di base, di spettroscopia e di diffusione può fornire maggiori informazioni rispetto ai precedenti studi acquisiti con sistemi a più basso campo.Purpose. This study evaluated the sensitivity of a 3.0-Tesla (T) magnetic resonance imaging (MRI) in measuring cerebral phenylalanine using proton magnetic resonance spectroscopy and in assessing MR-documented whitematter changes by means of diffusion studies (diffusionweighted imaging, apparent diffusion coefficient map; diffusion tensor imaging) in patients with phenylketonuria. Materials and methods. Thirty-two patients with the

3.0-T morphological and angiographic brain imaging: a 5-years experience

Ever since the introduction of magnetic resonance (MR), imaging with 1.5 Tesla (T) has been considered the gold standard for the study of all areas of the body. Until not long ago, higher-field MR equipment was exclusively employed for research, not for clinical use. More recently, the introduction of 3.0-T MR machines for new and more sophisticated clinical applications has resulted in important benefits, especially in neuroradiology. Indeed, their high gradient power and field intensity (3.0 T) allow adjunctive and more advanced diagnostic methodologies to be performed with excellent resolution in a fraction of the acquisition time required with earlier machines. The purpose of this paper is to illustrate the distinctive semeiological characteristics of 3.0-T morphological and angiographic brain imaging compared with lower-field systems and highlight the respective advantages and drawbacks based on the experience gained in the first 5 years from the installation of a 3.0-T magnet.

Dosimetric Characterization and Image Quality Assessment in Breast Tomosynthesis

The aim of this paper was to investigate the diagnostic potential of tomosynthesis imaging compared with the performance of 2-D digital mammography in terms of radiation dose and image quality. In particular, suitable dosimeter and phantom were used for quantifying the average glandular dose and image quality parameters, respectively. First, according to standard protocols and European guidelines, the characterization of the used tomosynthesis system was carried out to verify the reliability of characteristic parameters of the system. Successively, the absorbed dose was calculated by means of experimental measurements and the application of estimation methods. The calculated dose was then compared with the value provided by the system; this approach has confirmed the tendency of mammography equipment manufacturers to underestimate the mean glandular dose. Finally, the detection capability of different details with different contrasts was objectively assessed for both breast tomosynthesis and 2-D mammography.

High-Field MRI and Safety: I. Installations

High-field magnetic resonance (MR), originally developed in the framework of spectroscopy and functional neuroradiology, has become to our days an important diagnostic tool not only in research but also in advanced clinical practice.

Fenilchetonuria: Studio RM a 3,0 T delle alterazioni della sostanza bianca con imaging di base, di spettroscopia e di diffusione

PurposeThis study evaluated the sensitivity of a 3.0-Tesla (T) magnetic resonance imaging (MRI) in measuring cerebral phenylalanine using proton magnetic resonance spectroscopy and in assessing MR-documented white-matter changes by means of diffusion studies (diffusion-weighted imaging, apparent diffusion coefficient map; diffusion tensor imaging) in patients with phenylketonuria.Materials and methodsThirty-two patients with the classical clinical and biochemical deficits of phenylketonuria underwent biochemical (blood phenylalanine), genotypic (phenylalanine hydroxylase gene) and radiological investigation by means of MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging with a 3.0-T scanner.ResultsPeriventricular and subcortical white-matter changes were detected on all MR scans. In 29/32 patients, proton magnetic resonance spectroscopy easily documented abnormal signal elevation at 7.36 ppm, corresponding to phenylalanine, despite its low concentration. Phenylalanine signal amplitude relative to the creatine/phosphocreatine signal increased linearly with blood phenylalanine values (r 0.7067; p<0.001). Diffusion MRI demonstrated hyperintensity in the areas exhibiting MRI changes as well as decreased apparent diffusion coefficient values, but fractional anisotropy indices were normal.ConclusionsThe high signal, together with better spectral, spatial, contrast and temporal resolution, makes the 3.0-T MR the most suitable technique in the study of the phenylketonuria. In particular, the multimodal approach with MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging can provide more information than previous studies performed with low-field systems.RiassuntoObiettivoValutare in pazienti con fenilchetonuria la sensibilità di un sistema di risonanza magnetica (RM) a 3,0 Tesla (T) nel misurare la fenilalanina cerebrale con la spettroscopia protonica e nel documentare le alterazioni della sostanza bianca rilevate con lo studio RM di base utilizzando gli studi di diffusione (imaging pesato in diffusione, mappa del coefficiente di diffusione apparente, imaging del tensore).Materiali e metodiTrentadue pazienti con il deficit clinico e biochimico classico di fenilchetonuria sono stati sottoposti ad uno studio biochimico (livelli della fenilalanina cerebrale), genotipico (gene fenilalanina idrossilasi) e radiologico mediante uno studio RM di base, di spettroscopia e di diffusione con apparecchiatura a 3,0 T.RisultatiIn tutte le immagini RM morfologiche sono state rilevate alterazioni della sostanza bianca periventricolari e sottocorticali. In 29 pazienti su 32 la spettroscopia protonica ha rilevato facilmente un picco anomalo a 7,36 ppm corrispondente alla fenilalanina nonostante la sua bassa concentrazione. Ls’ampiezza del segnale della fenilalanina relativo al rapporto creatina/fosfocreatina incrementa linearmente con la fenilalanina ematica (r=0,7067; p<0,001). Lo studio di diffusione ha evidenziato iperintensità focali nelle aree di alterato segnale documentate con lo studio RM di base, valori di coefficiente di diffusione apparente ridotto e indici di anisotropia frazionata normale.ConclusioniLs’alto segnale assieme alla maggiore risoluzione spettrale, spaziale, di contrasto e temporale rende il sistema 3,0 T ideale per lo studio della fenilchetonuria. In particolare ls’approccio multimodale con imaging RM di base, di spettroscopia e di diffusione può fornire maggiori informazioni rispetto ai precedenti studi acquisiti con sistemi a più basso campo.Purpose. This study evaluated the sensitivity of a 3.0-Tesla (T) magnetic resonance imaging (MRI) in measuring cerebral phenylalanine using proton magnetic resonance spectroscopy and in assessing MR-documented whitematter changes by means of diffusion studies (diffusionweighted imaging, apparent diffusion coefficient map; diffusion tensor imaging) in patients with phenylketonuria. Materials and methods. Thirty-two patients with the

Phenylketonuria: white-matter changes assessed by 3.0-T magnetic resonance (MR) imaging, MR spectroscopy and MR diffusion Fenilchetonuria: studio RM a 3,0 T delle alterazioni della sostanza bianca con imaging di base, di spettroscopia e di diffusione

PurposeThis study evaluated the sensitivity of a 3.0-Tesla (T) magnetic resonance imaging (MRI) in measuring cerebral phenylalanine using proton magnetic resonance spectroscopy and in assessing MR-documented white-matter changes by means of diffusion studies (diffusion-weighted imaging, apparent diffusion coefficient map; diffusion tensor imaging) in patients with phenylketonuria.Materials and methodsThirty-two patients with the classical clinical and biochemical deficits of phenylketonuria underwent biochemical (blood phenylalanine), genotypic (phenylalanine hydroxylase gene) and radiological investigation by means of MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging with a 3.0-T scanner.ResultsPeriventricular and subcortical white-matter changes were detected on all MR scans. In 29/32 patients, proton magnetic resonance spectroscopy easily documented abnormal signal elevation at 7.36 ppm, corresponding to phenylalanine, despite its low concentration. Phenylalanine signal amplitude relative to the creatine/phosphocreatine signal increased linearly with blood phenylalanine values (r 0.7067; p<0.001). Diffusion MRI demonstrated hyperintensity in the areas exhibiting MRI changes as well as decreased apparent diffusion coefficient values, but fractional anisotropy indices were normal.ConclusionsThe high signal, together with better spectral, spatial, contrast and temporal resolution, makes the 3.0-T MR the most suitable technique in the study of the phenylketonuria. In particular, the multimodal approach with MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging can provide more information than previous studies performed with low-field systems.RiassuntoObiettivoValutare in pazienti con fenilchetonuria la sensibilità di un sistema di risonanza magnetica (RM) a 3,0 Tesla (T) nel misurare la fenilalanina cerebrale con la spettroscopia protonica e nel documentare le alterazioni della sostanza bianca rilevate con lo studio RM di base utilizzando gli studi di diffusione (imaging pesato in diffusione, mappa del coefficiente di diffusione apparente, imaging del tensore).Materiali e metodiTrentadue pazienti con il deficit clinico e biochimico classico di fenilchetonuria sono stati sottoposti ad uno studio biochimico (livelli della fenilalanina cerebrale), genotipico (gene fenilalanina idrossilasi) e radiologico mediante uno studio RM di base, di spettroscopia e di diffusione con apparecchiatura a 3,0 T.RisultatiIn tutte le immagini RM morfologiche sono state rilevate alterazioni della sostanza bianca periventricolari e sottocorticali. In 29 pazienti su 32 la spettroscopia protonica ha rilevato facilmente un picco anomalo a 7,36 ppm corrispondente alla fenilalanina nonostante la sua bassa concentrazione. Ls’ampiezza del segnale della fenilalanina relativo al rapporto creatina/fosfocreatina incrementa linearmente con la fenilalanina ematica (r=0,7067; p<0,001). Lo studio di diffusione ha evidenziato iperintensità focali nelle aree di alterato segnale documentate con lo studio RM di base, valori di coefficiente di diffusione apparente ridotto e indici di anisotropia frazionata normale.ConclusioniLs’alto segnale assieme alla maggiore risoluzione spettrale, spaziale, di contrasto e temporale rende il sistema 3,0 T ideale per lo studio della fenilchetonuria. In particolare ls’approccio multimodale con imaging RM di base, di spettroscopia e di diffusione può fornire maggiori informazioni rispetto ai precedenti studi acquisiti con sistemi a più basso campo.Purpose. This study evaluated the sensitivity of a 3.0-Tesla (T) magnetic resonance imaging (MRI) in measuring cerebral phenylalanine using proton magnetic resonance spectroscopy and in assessing MR-documented whitematter changes by means of diffusion studies (diffusionweighted imaging, apparent diffusion coefficient map; diffusion tensor imaging) in patients with phenylketonuria. Materials and methods. Thirty-two patients with the

L'imaging morfologico ed angiografico cerebrale 3,0 T: L'esperienza di 5 anni

Ever since the introduction of magnetic resonance (MR), imaging with 1.5 Tesla (T) has been considered the gold standard for the study of all areas of the body. Until not long ago, higher-field MR equipment was exclusively employed for research, not for clinical use. More recently, the introduction of 3.0-T MR machines for new and more sophisticated clinical applications has resulted in important benefits, especially in neuroradiology. Indeed, their high gradient power and field intensity (3.0 T) allow adjunctive and more advanced diagnostic methodologies to be performed with excellent resolution in a fraction of the acquisition time required with earlier machines. The purpose of this paper is to illustrate the distinctive semeiological characteristics of 3.0-T morphological and angiographic brain imaging compared with lower-field systems and highlight the respective advantages and drawbacks based on the experience gained in the first 5 years from the installation of a 3.0-T magnet.

3.0-T morphological and angiographic brain imaging: a 5-years experience L'imaging morfologico ed angiografico cerebrale 3,0 T: l'esperienza di 5 anni

Ever since the introduction of magnetic resonance (MR), imaging with 1.5 Tesla (T) has been considered the gold standard for the study of all areas of the body. Until not long ago, higher-field MR equipment was exclusively employed for research, not for clinical use. More recently, the introduction of 3.0-T MR machines for new and more sophisticated clinical applications has resulted in important benefits, especially in neuroradiology. Indeed, their high gradient power and field intensity (3.0 T) allow adjunctive and more advanced diagnostic methodologies to be performed with excellent resolution in a fraction of the acquisition time required with earlier machines. The purpose of this paper is to illustrate the distinctive semeiological characteristics of 3.0-T morphological and angiographic brain imaging compared with lower-field systems and highlight the respective advantages and drawbacks based on the experience gained in the first 5 years from the installation of a 3.0-T magnet.

High-Field MRI and Safety: I. Installation

High-field magnetic resonance (MR), originally developed in the framework of spectroscopy and functional neuroradiology, is set to become an important diagnostic tool not only in research but also in advanced clinical practice. High magnetic fields afford a better signal/noise ratio (SNR) and consequently better spatial resolution in a shorter acquisition time, even though the diagnostic outcome is then subject to the dependence on the magnetic field of other factors that variously contribute to image quality. The rationale for the utilization of high magnetic fields in MR diagnostic imaging is obvious. The distribution of the population into two spin levels is statistically determined: