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T Scarabino

Publications and source records attributed to T Scarabino.

At least 19 recordsLinked to original sources
PubMed2006

Spectroscopic, diffusion and perfusion magnetic resonance imaging at 3.0 Tesla in the delineation of glioblastomas: preliminary results.

Recent advances in magnetic resonance imaging (MRI) have allowed the evaluation of metabolic, diffusion and hemodynamic features of malignant gliomas. The aim of this study was to evaluate whether such information provided useful, complementary information to conventional MRI for improving the evaluation of glioblastoma extent. Ten patients with glioblastoma multiforme underwent conventional MRI, proton MR spectroscopic imaging (1H-MRSI), perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI). Metabolite signals, including normalized choline, N-acetylaspartate, creatine and lactate/lipids, were obtained by 1H-MRSI; apparent diffusion coefficient (ADC) by DWI; and relative cerebral blood volume (rCBV) by PWI. In edematous-appearing areas, 3 multiparametric patterns were identified: infiltrating tumor, with abnormal metabolite ratios, lower ADC and higher rCBV; pure edema, with normal metabolite ratios, higher ADC and lower rCBV; and tumor-infiltrated edema, with abnormal metabolite ratios and intermediate ADC and rCBV. In normal-appearing areas, 2 multiparametric patterns were identified: tumor-infiltrated tissue, with abnormal metabolite ratios and higher rCBV; and normal tissue, with normal MR parameters. The combination of 1H-MRSI, DWI and PWI features contributed to delineation of glioblastomas, offering information not available with conventional MRI. This approach may enhance the assessment of brain gliomas, providing useful information for guiding stereotactic biopsies, surgical resection and radiation treatment.

Brain Neoplasms↗
PubMed2005

Supratentorial low-grade gliomas. Neuroradiology.

The radiologic modality that most likely provides the imaging information needed in a patient suspected of having a brain tumors is magnetic resonance imaging. A brain tumors can be reliably ruled out, if the standard magnetic resonance examination is performed properly and experts interpret the results as negative for tumor. In this paper we will illustrate morphological aspects of low-grade supratentorial neoplasms, including tumors of neuroepithelial tissue, such as low-grade diffuse fibrillary astrocytomas, and circumscribed astrocytic lesions (pilocytic astrocytoma, pleomorphic xantoastrocytoma and subependymal giant cell astrocytoma). Then the main practical applications of functional imaging in neurosurgery will be also debated.

Brain↗
PubMed2004

Perfusion- and BOLD-based fMRI in the study of a human pathological model for task-related flow reductions.

In the present work, an arteriovenous malformation was taken as a pathological model for studying task-related flow decreases during a motor task. Combined Blood Oxygen Level Dependent (BOLD)-perfusion experiments were applied in order to evaluate the relative sensitivity of these techniques to task-related reductions in cerebral blood flow (CBF). Results shows that, by matching the sensitivity of the methods (which exhibit a different contrast-to-noise ratio) in the primary motor cortex, the spatial extent of the regions of decreased perfusion signal is larger than those of the BOLD signal reduction. The above finding suggests that perfusion imaging, that already represents a gold standard method in the detection of vascular phenomena, may estimate task-related flow decreases in a functional time-series better than BOLD.

Adult↗
PubMed2003

High-field proton MRS of human brain.

Proton magnetic resonance spectroscopy (1H-MRS) of the brain reveals specific biochemical information about cerebral metabolites, which may support clinical diagnoses and enhance the understanding of neurological disorders. The advantages of performing 1H-MRS at higher field strengths include better signal to noise ratio (SNR) and increased spectral, spatial and temporal resolution, allowing the acquisition of high quality, easily quantifiable spectra in acceptable imaging times. In addition to improved measurement precision of N-acetylaspartate, choline, creatine and myo-inositol, high-field systems allow the high-resolution measurement of other metabolites, such as glutamate, glutamine, gamma-aminobutyric acid, scyllo-inositol, aspartate, taurine, N-acetylaspartylglutamate, glucose and branched amino acids, thus extending the range of metabolic information. However, these advantages may be hampered by intrinsic field-dependent technical difficulties, such as decreased T2 signal, chemical shift dispersion errors, J-modulation anomalies, increased magnetic susceptibility, eddy current artifacts, limitations in the design of homogeneous and sensitive radiofrequency (RF) coils, magnetic field instability and safety issues. Several studies demonstrated that these limitations could be overcome, suggesting that the appropriate optimization of high-field 1H-MRS would expand the application in the fields of clinical research and diagnostic routine.

Algorithms↗
PubMed2003

High field functional MRI.

Functional magnetic resonance imaging (fMRI) has become the most widely used approach for studying brain functions in humans. The rapid and widespread diffusion of fMRI has been favoured by the properties this technique presents, and particularly by its sensitivity in analysing brain functional phenomena and by the lack of biological invasiveness, resulting in an unprecedented and unparalleled flexibility of use. These properties of fMRI brought the functional examination of the brain within the reach of the whole neuroscience community and have appreciably stimulated the research on the functional processes of the living brain. Among the main features of fMRI, its spatial and temporal resolution represents clear advantages compared with the other methods of functional neuroimaging. In fact, the high spatial resolution of fMRI permits to produce more precise and better localised information, and its temporal resolution provides the potential of a better understanding of neural dynamics at the level of single functional areas and of the neural constituents of functional patterns. A fundamental possibility of improving spatial and temporal resolution without excessively degrading signal-to-noise ratio consists in the use of high magnetic field intensity fMRI units. Besides, high field units make the use of more demanding fMRI paradigms, like single trial event related studies, much more compatible with the need of a solid statistical evaluation. This has notably promoted the diffusion of high field MRI units for human studies throughout the world, with very high field MRI units, up to 8 T, working in a few research centres, and a larger number of MRI units with field intensity ranging between 3 and 5 T.

Brain↗
PubMed2000

MRI T-staging of laryngeal tumours: role of contrast medium.

Our aim was to evaluate the relative diagnostic accuracy of MRI without contrast medium and MRI before and after contrast medium in the assessment of T-staging of laryngeal tumours. We studied 25 men (mean age 51.8, range 41-61) with laryngeal squamous cell carcinomas, using Spin-echo (SE) T1-weighted and fast SE T2-weighted sequences. The T1-weighted sequences were then repeated after gadolinium-diethylene-triaminepenta-acetic acid (Gd DTPA) 0.1 ml/kg. All patients then underwent biopsy and surgery. Two radiologists independently assessed the anonymised images by filling-out two multiple-choice forms, one for each technique, at a 2 week interval. The forms included a judgement concerning tumour identification and infiltration of the anterior commissure, supraglottic region, arytenoid cartilage, Morgagni's ventricle, paraglottic space, thyroid and cricoid cartilages, thyro-hyo-epiglottic space, vocal cords, subglottic region, and epiglottis. Similar forms were filled out by the surgeon and the pathologist after surgery. The sensitivity, specificity and diagnostic accuracy of MRI were unaffected by the use of contrast medium. Since it did not provide additional staging information, its continued routine use in these cases is not justified.

Adult↗
PubMed2000

Proton MR spectroscopy in connatal Pelizaeus-Merzbacher disease.

BACKGROUND: Pelizaeus-Merzbacher disease (PMD) is a rare dysmyelinating disorder characterised by early pendular nystagmus, often rotatory and muscular hypotonia with subsequent ataxia, spasticity and mental retardation. Various point mutations or duplications in the PLP gene on the X chromosome are responsible for PMD in the majority of patients. Autosomal recessive inheritance, particularly in the connatal form, cannot be excluded. Three different forms of the disease have been identified based on their onset, progression and severity of myelin pathology indicated by MRI features. Objective. To determine if MR spectroscopy is useful in the diagnosis of the connatal form of PMD. MATERIALS AND METHODS: Proton MR spectroscopy was performed on two children with connatal PMD. RESULTS: Our patients showed a markedly decreased peak of Cho. This alteration is well represented by quantitative analysis of the NAA-to-Cho ratio, which is the most important ratio affected. A significant decrease of the Cho-to-Cr ratio is also present. In the connatal form of PMD, global lack of myelination may be relevant, as demonstrated by a significant Cho peak reduction. CONCLUSIONS: Proton MR spectroscopy may be of diagnostic value in metabolic and destructive disorders of the brain. A greater number of patients with connatal PMD is needed in order to elucidate the significance of reduction of the Cho peak.

Brain↗
PubMed1999

Proton magnetic resonance spectroscopy of the brain in pediatric patients.

H1-MRS is a non-invasive technique which provides different levels of information on brain tissue: the N-acetyl aspartate (NAA) is an indicator of neuronal development, the choline containing compound peak (Cho) provides information on myelination and on cell membrane turnover and gliosis, inositol (Ins) is considered a marker of neuronal degeneration. Lactate may be detected in presence of defective energy metabolism. In the perineonatal period, the brain is apt to be insulted by a variety of events including asphyxia, hypoxemia, hemorrhage, which may subsequently cause delay in development. It is clinically important to assess the degree of brain damage and to obtain the prognostic information in the neonatal and early infantile period. MRS has become available for clinical examinations of the brain during development and these techniques can be used to document improvement or the progression towards irreversible damage.

Adolescent↗
PubMed1999

Osteochondroma of the L-5 vertebra: a rare cause of sciatic pain. Case report.

Solitary or multiple osteochondromas, which are benign bone tumors that usually occur in the long bones, are rarely found in the vertebral column. When present in the spine, however, they have a predilection for the cervical or upper thoracic regions. The authors present the case of a solitary osteochondroma arising from the left L-5 articular process that contributed to sciatica; complete cure was achieved following its removal. It is possible to speculate that the cartilage of secondary ossification centers can be the origin of aberrant islands of cartilaginous tissue that cause the osteochondroma to form. The more rapid the ossification process of these centers, the greater the probability that aberrant cartilage will form. Therefore, the fact that osteochondromas are more frequently located in the higher segments of the vertebral column could be explained by the different durations of the ossification processes in these centers, which increase gradually below the cervical segments.

Adult↗
PubMed1999

Contrast-enhanced MR angiography (CE MRA) in the study of the carotid stenosis: comparison with digital subtraction angiography (DSA).

PURPOSE: To determine sensitivity, specificity and diagnostic accuracy of contrast-enhanced magnetic resonance angiography (CE MRA) compared to digital subtraction angiography (DSA) in the study of carotid stenosis. METHODS AND MATERIAL: We studied 23 patients with suspected cerebro-vascular insufficiency by carotid stenosis. Diagnostic examinations by means of CE MRA and DSA were carried out within 24 hours of each other. A 1.5 T superconductive magnet (Signa-General Electric) was used for CE MRA. This technique was performed using a fast spoiled gradient echo recalled (SPGR) sequence acquired in coronal plane 13 sec after injection of contrast medium. Imaging parameters were: TR/TE/FA 8 msec/1 msec/60 degrees, matrix 256 x 128, 1 excitation, FOV 18 x 13 cm, 28 slices per slab, slice thickness of 1 mm, acquisition time of 32 sec. The post-processing was performed using maximum intensity projection (MIP) and targeted MIP. For DSA examinations a Politron 1000 VR unit (Siemens) was used. RESULTS: In the identification and quantification of lesions, CE MRA showed values of 100%. In particular, in comparison to DSA, CE MRA was accurate in diagnosing all true negative and positive cases. The location of stenosis evaluated with CE MRA agreed in all cases with DSA. CONCLUSION: In our experience CE MRA proved to be a very valuable technique in diagnosing carotid stenosis, showing the same diagnostic accuracy as DSA. In this way CE MRA appears to be a substantial alternative technique to conventional MRA and other non-invasive diagnostic methods.

Aged↗
PubMed1998

Carotid stenosis: a comparison between MR and spiral CT angiography.

We performed a preliminary study comparing three-dimensional time-of-flight (3 D TOF) magnetic resonance angiography (MRA) and spiral CT angiography (SCTA) in the detection and assessment of internal carotid artery stenosis. Digital subtraction angiography (DSA) was the reference examination. We examined 20 patients with signs of cerebrovascular insufficiency, who underwent MRA, SCTA and DSA within a 3 day period. Both internal carotid arteries were assessed by three blinded readers for degree of stenosis at two different levels (bulb and remaining section) giving a total of 80 assessments. Interobserver variability, sensitivity, specificity, diagnostic accuracy, concordance, overestimation and underestimation were assessed. Interobserver variability was not statistically significant. MRA showed higher sensitivity, specificity, diagnostic accuracy and concordance than SCTA (92.0% vs 80.8%, 98.2% vs 96.4%, 96.3% vs 91.3% and 96.0% vs 88.0%, respectively). MRA gave rise to a 5.0% overestimation rate, whereas SCTA occasioned a 7.5% underestimation rate. These differences are not statistically significant. These results suggest that MRA is a more useful, noninvasive modality for assessment of the internal carotid artery with a more than 70% stenosis.

Aged↗
PubMed1998

High-resolution magnetic resonance angiography of the internal carotid artery: 2D vs 3D TOF in stenotic disease.

The aim of this study was to compare high-resolution 2D TOF with high-resolution 3D TOF in the study of internal carotid artery disease. Sixty-four patients with clinical signs of cerebrovascular insufficiency were studied with a superconductive 1.5 T magnet using two techniques: 2D and 3D TOF. Digital subtraction angiography (DSA) was the gold standard. The 2D TOF technique was performed using the following parameters: TR/TE/FA/MA 49 ms/9 ms/60 degrees/512 x 256; the 3D TOF was performed with the following parameters: TR/TE/FA/MA 50 ms/8 ms/20 degrees/512 x 256. The 2D TOF agreed with DSA in 116 of 128 diagnostic judgments (90%) and overestimated seven times. The 3D TOF technique agreed with DSA in 125 of 128 diagnostic judgments (97%) with one overestimation and two underestimations. There was no statistically significant difference (P < 0.05) between the two different techniques. Our study confirms the high reliability of the methodology carried out with the high-resolution 2D and 3D technique.

Angiography, Digital Subtraction↗
PubMed1998

MR angiography in carotid stenosis: a comparison of three techniques.

PURPOSE: To compare the accuracy of three different magnetic resonance angiography (MRA) techniques for studying steno-occlusive disease of carotid arteries. METHODS: 64 patients were evaluated with three MRA techniques- three-dimensional (3D) time-of-flight (TOF), two-dimensional (2D) TOF, and 3D Phase-Contrast (PC); the acquisition was in the axial plane, the volume included the carotid bifurcation. Digital subtraction angiography (DSA) was considered the 'gold standard'. The MRA images were reprojected with a maximum intensity pixel ray-tracing (MIP) algorithm. The three MRA techniques were blindly graded as normal, mildly stenotic (0-29%), moderately stenotic (30-49%), severely stenotic (70-99%), or occluded. RESULTS: DSA provided 128 diagnostic judgments: 92 were negatives and 36 positives. 2D TOF was in agreement with angiography in 116 of 128 cases (90%), but overestimated the results in seven cases and underestimated in five cases. 3D TOF agreed with angiography in 125 of 128 cases (97%), with one overestimation and two under estimations. 3D PC was concordant in 116 of 128 cases (90%), overestimating in six cases, underestimating in six cases. The sensitivity, specificity and diagnostic accuracy for 2D TOF was, respectively 84%, 94%, and 92%, while for 3D TOF was 94%, 100%, and 98%, and for 3D PC 86%, 98%, and 95%. The comparison of the three different MRA techniques provided no statistically significant difference (Friedman test P < 0.05). CONCLUSION: The high degree of diagnostic accuracy of MRA found in the study of the steno-occlusive disease of the carotid arteries confirms the high degree of reliability of this methodology carried out with the 3D TOF technique, compared to 2D TOF and 3D PC.

Carotid Arteries↗
PubMed1998

[Stenosis-occlusion of the carotid bifurcation. Angiography with MR and contrast media versus digital angiography].

PURPOSE: To evaluate the comparative sensitivity, specificity and diagnostic accuracy of contrast enhanced magnetic resonance angiography (CE MRA) and digital subtraction angiography (DSA) in the study of carotid bifurcation stenoses. MATERIAL AND METHODS: Twenty-three patients with suspected cerebrovascular insufficiency by carotid stenosis were examined with CE MRA and DSA within 24 hours of each other. A 1.5 superconductive unit (Signa, General Electric) was used for CE MRA; fast spoiled gradient echo recalled (SPGR) images were acquired on the coronal plane 12 s after contrast medium injection, with the following parameters: TR/TE/FA 8/1/60, MA 256 x 128, NEX 1, FOV 18 x 13, slices/slab 28, slice thickness 1 mm, TA 32 s. The images were postprocessed with the maximum intensity projection (MIP) and the targeted MIP algorithms. A Siemens Politron 1000 VR unit was used for DSA examinations. RESULTS: DSA diagnosed 21 true positives, namely 4 grade II, 4 grade III, 10 grade IV and 3 grade V stenoses. CE MRA scored 100% in stenosis identification and grading, accurately diagnosing all the true negatives and the true positives and was always in agreement with DSA as to stenosis site. CONCLUSION: CE MRA can be considered the technique of choice to study stenosis occlusion in the epiaortic vessels, because it permits a rapid panoramic study of the neck vessels and accurate stenosis grading with similar patterns to those of DSA. Thus, CE MRA appears to be a valid alternative to DSA.

Aged↗
PubMed1997

[Magnetic resonance angiography in stenosing-occlusive diseases of the carotid arteries: 3D with time of flight versus 3D with phase contrast].

We assessed the comparative sensitivity, specificity and diagnostic accuracy of 3D time of flight (TOF) versus 3D phase contrast (PC) MRA in the study of stenoses/occlusions of the extracranial carotid artery. Fifty-four patients were submitted to MRA because of their symptoms or of signs of cerebrovascular insufficiency. 3D TOF and 3D PC axial slices were acquired with a high field magnet; digital angiography was the gold standard. The parameters of 3D TOF acquisitions were: TR/TE/FA 50/8/20, 1 NEX, 512 x 256 matrix, 16 x 12 FOV, 1 axial slab of 60 slices, 1 mm slice thickness, superior presaturation band, ramp pulse, TA 10-18 minutes. 3D PC parameters were: TR/TE/ FA 25/9/20, 1 NEX, 256 x 128 matrix, 18 x 13 FOV, 1 axial slab of 60 slices, 1 mm slice thickness, VENC 35 cm/s, TA 10-15 minutes. 3D TOF MRA was in agreement with digital angiography in 95.6% of cases (22/23), overestimating a grade 3 stenosis as grade 4 (one case, 4.3%) and underestimating no stenoses. 3D PC MRA was in agreement with digital angiography in 78.2% of cases (18/23), overestimating three stenoses (13%); one grade 1 as grade 2 and two grade 4 as grade 5; two stenoses were underestimated (8.6%); one grade 4 as grade 3 and one grade 4 as grade 2. Sensitivity, specificity and diagnostic accuracy were 91.4%, 98.9% and 95.7% for 3D TOF, versus 83.2%, 97.2% and 92.3% for 3D PC, respectively. The two MRA techniques had different semiology. In spite of outstanding background noise suppression, 3D PC poorly depicted the turbulent flow at the carotid bifurcation in carotid stenoses. Therefore, 3D TOF appears a better technique to study stenoses/occlusions of the extracranial carotid arteries.

Carotid Stenosis↗
PubMed1997

Spiral CT angiography in the study of the carotid stenoses.

PURPOSE: To determine sensitivity, specificity and diagnostic accuracy of spiral CT angiography (S-CTA) compared to Digital Subtraction Angiography (DSA). MATERIALS AND METHODS: We studied 40 patients with suspected cerebro-vascular insufficiency by carotid stenosis. Diagnostic examinations by means of S-CTA and DSA were carried out within 24 hours of each other. Twelve of these patients underwent thromboendoarterectomy (TEA). Prospeed SX GE was used for S-CTA. Post-processing was performed using Maximum Intensity Projection (MIP) after deleting osteo-muscular structures and CT angiograms were displayed in an oblique anterior view at an angle of 10 degrees-15 degrees along the longitudinal axis. For DSA examinations, a Siemens Politron 1000 VR unit was used. RESULTS: In this study S-CTA showed values of sensitivity, specificity and diagnostic accuracy of 88%, 100% and 96%, respectively. CONCLUSIONS: In the future, with the improvement of non-invasive techniques (S-CTA, MRA), DSA should be replaced, as the gold-standard, in the evaluation of stenotic disease of the carotid bifurcation.

Adult↗