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Biomedical subjects

S Magnaldi

Publications and source records attributed to S Magnaldi.

At least 19 recordsLinked to original sources
PubMed1997

Bone marrow relaxation times in Gaucher disease before and after enzyme replacement therapy.

The aim of this work was to monitor the effectiveness of enzyme replacement therapy on the basis of the changes in T1 relaxation times in Gaucher patients. A total of 26 patients underwent MR before enzyme replacement therapy; of them, 18 have been followed-up. A total of 22 age-matched controls underwent the same MR study. Scans were focused on the femoral neck, and T1 relaxation times were measured by means of a mixed spin-echo inversion recovery sequence. The T1 relaxation times in Gaucher patients were significantly longer than normal (p < 0.05). After enzyme replacement therapy, T1 relaxation times gradually became closer to those of control subjects, and there was also a significant decrease (p < 0.01) with respect to values before therapy, probably due to an increase in the fat/water ratio. Evaluation of T1 relaxation time may supply a useful indication of Gaucher disease regression after enzyme replacement therapy particularly in those cases in which a normal skeletal appearance corresponds to prolonged T1 relaxation times.

Adolescent↗
PubMed1997

Assessment of pituitary microadenomas: comparison between 2D and 3D MR sequences.

The aim of this study was to compare the diagnostic value and image quality of two different T1-weighted MR sequences in the evaluation of PRL-secreting pituitary microadenomas. Twenty-four patients with a clinical diagnosis of pituitary microprolactinoma were prospectively examined with both a 2D SE and a 3D turbo-SE T1-weighted coronal sequence, before and after intravenous contrast medium administration. Evaluation of MR images was done only on postcontrast images and considered the number of slices in which the lesions were visible and image quality, which was evaluated by both a subjective score and objective parameters (signal-to-noise and contrast-to-noise ratios). Pituitary microprolactinomas are visible in a higher number of slices in 3D TSE sequences; the subjective scores for image quality and signal-to-noise ratios were similar in both 2D and 3D sequences; the contrast-to-noise ratio was always higher in 3D sequences. In patients with hyperprolactinemia, the authors recommend using coronal 3D TSE T1-weighted sequences for evaluation of the pituitary region. 2D SE T1-weighted sequences may be considered if a shorter examination time is required (i.e., for claustrophobic patients) and in assessment or follow-up of microadenomas when a larger size lesion is clinically suspected.

Adult↗
PubMed1995

Absolute quantitation of brain 1H nuclear magnetic resonance spectra. Comparison of different approaches.

RATIONALE AND OBJECTIVES: Three different calibration techniques of 1H localized nuclear magnetic resonance (NMR) spectra were applied to a group of healthy volunteers. Absolute concentrations of the metabolites and their standard deviations were compared, and the clinical feasibility of these calibration technique is discussed. METHODS: Eighteen healthy volunteers were included in the study. Both water and creatine were used as internal standard, and a pertinent solution of metabolites was used as an external standard. The T2 relaxation times of the brain metabolites were evaluated in each examination. RESULTS AND CONCLUSIONS: The concentrations obtained using water as an internal standard and using an external standard are very similar, and the first of these methods show smaller standard deviations. The authors' results show that the use of creatine as an internal standard may induce systematic errors in absolute calibration because of the uncertainty on the true creatine concentration.

Adult↗
PubMed1995

[Tridimensional reconstructions of intra- and extracranial arteries using computerized tomography].

Three-dimensional Computed Tomographic Angiography (3D CTA) is a new imaging technique for vascular structures. This study was aimed at investigating the diagnostic role of 3D CTA in the intracranial and extracranial arteries. Fifteen patients with intracranial artery disease (thirteen with aneurysms and two with arteriovenous malformations) and fifteen patients with stenosis of the common, internal or external carotid arteries underwent 3D CTA. All patients had been examined with intraarterial angiography. The CT examinations were performed with dynamic scanning during intravenous contrast agent administration. Three-millimeter thick contiguous slices were obtained in the cervical region and 1.5-mm contiguous slices in the intracranial region. CT findings were processed to produce 3D views on an independent workstation. 3D CTA results were compared with those of intraarterial DSA in all cases. Agreement was found in 13 of 15 cases of intracranial vascular abnormalities, and in 26 of the 30 carotid arteries in classifying the severity of the stenosis. The 3D views, which exhibit an excellent image quality, seem to be comparable to angiography in the intracranial and extracranial arteries. The main advantages of this technique are: 1) its low invasivity since only an intravenous contrast agent injection is required; 2) its easy and fast acquisition (2-3 minutes are needed if a non-spiral CT unit is used and less than one minute with spiral CT); 3) good demonstration of the calcified plaques which can be also removed with the softwares available at the workstation, to show the overall vessel lumen; 4) thanks to its simplicity the examination can also be performed in emergency (i.e. in patients with subarachnoid hemorrhage, if plain CT is positive for subarachnoid bleeding). Its main limitations are: 1) the need of an adequate concentration of contrast agent in the vessels; 2) artifacts due to calcified and bone structures; 3) no information about vessel inflow; 4) limited discrimination between arteries and veins in some areas (cavernous sinus); 5) limited field of view compared to angiography.

Carotid Arteries↗
PubMed1994

Neurofibromatosis type 1: the evolution of deep gray and white matter MR abnormalities.

PURPOSE: To investigate the evolution of deeply located high-signal-intensity abnormalities of the brain on T2-weighted MR images of patients with neurofibromatosis type 1 (NF-1). METHODS: The study consists of two patient groups: 1) retrospective evaluation of MR scans of 24 symptomatic NF-1 patients, 10 of whom were sequentially studied, and 2) prospective MR evaluations of 20 asymptomatic NF-1 subjects from 14 families; 2 of these families were sequentially studied. RESULTS: Deeply located, high-signal-intensity abnormalities on T2-weighted images were noted in 34 of 44 NF-1 subjects (77%). If NF-1 patients are grouped according to age, 28 of 30 subjects (93%) younger than 15 years had the lesions, whereas 4 of 7 subjects (57%) between 16 and 30 years, and 2 of 7 subjects (29%) older than 31 years had lesions. High-signal lesions in basal ganglia and brain stem were demonstrated in all decades with relatively high frequency. Lesions in the cerebellar white matter and dentate nuclei were mainly found in the patients younger than 10 years, and never found after the third decade. In 13 sequential studies (mean interval, 24 months), lesions appeared to increase in size in 3, remain unchanged in size in 2, and decrease in size in 7. One subject showed a mixed pattern of lesion size change. CONCLUSIONS: Deeply located high-signal-intensity lesions on T2-weighted MR images are more evident in young NF-1 patients. The underlying brain abnormality, while pathologically unproved, is probably transient.

Adolescent↗
PubMed1993

Alzheimer's disease histologically proven studied by MRI and MRS: two cases.

Two patients affected by severe Alzheimer's disease (AD) were investigated by MRI and image-guided 31P MRS. In one case, 1H MRS was additionally performed. In both cases the diagnosis of AD was confirmed, post mortem, by the pathologist. The spectral parameters of the 31P MR spectra were estimated by fitting the 31P MR signals in the time domain. Our 31P MRS results suggest that it is possible to detect the membrane catabolism, as indexed with the level of PDE resonances visible in in vivo 31P MRS, at least in severe AD cases. The 1H spectrum from AD brain showed a marked decrease of NAA signal respect to choline.

Aged↗
PubMed1992

Idiopathic anterior hypopituitarism: magnetic resonance imaging and clinical correlation.

We describe the anatomical abnormalities in the hypothalamic-pituitary region revealed by magnetic resonance imaging (MRI) in 10 patients, 8 men and 2 women, affected by idiopathic anterior hypopituitarism (IAH). In all cases contiguous sagittal and coronal T-1 weighted images were obtained. In 9 patients the high-intensity posterior lobe was missing, in almost all patients the pituitary stalk was thin and/or transected, and in 8 a bright T-1 nodule was detected at the infundibular apex, near the tuber cinereum, in the median eminence. None had diabetes insipidus. MRI proves to be very useful in understanding the etiopathogenesis of IAH.

Adult↗
PubMed1992

[Magnetic resonance in trigeminal neuralgia].

One of the possible causes of the so-called "essential" trigeminal neuralgia is a neurovascular compression of the fifth cranial nerve root at the pons. The demonstration of this hypothesis could orientate the surgical treatment to microvascular decompression. In order to evaluate the role of MRI in the diagnosis of trigeminal neuralgia due to neurovascular compression, the authors present the results of a prospective evaluation of the cranial MR studies of 18 neuralgic patients in comparison with a retrospective evaluation of the cranial MR studies of 50 healthy control subjects. The results show that neurovascular compression can be demonstrated in 83.3% of the neurological patients. In all cases a good correlation between the clinical symptoms, the side of positive MR findings and the surgical findings, when available, was demonstrated. On the other hand, neurovascular compression was demonstrated in 28% of the healthy control subjects. The authors conclude that neurovascular compression can be demonstrated in a high percentage of patients with the so-called "essential" trigeminal neuralgia. Compared with the other imaging modalities (angiography, Computed Tomography) MRI is the best technique in the diagnosis of this disease. In fact, MRI is not only able to differentiate the symptomatic from the essential type of neuralgia, but is also very sensitive in the identification of trigeminal neuralgia due to neurovascular compression. This diagnosis could direct the surgical treatment to microvascular decompression.

Adolescent↗
PubMed1990

[Encephalic lesions in neurofibromatosis: clinical manifestations and typical magnetic resonance findings].

Neurofibromatosis is the commonest neuroectodermal disease. It is characterized by dysplasias and/or tumors of organs and tissues derived from the embryonic ectoderm, mesoderm and endoderm, and most frequently presents with nervous system and cutaneous lesions. It can be classified as neurofibromatosis type 1 (NF-1 or von Recklinghausen disease) and neurofibromatosis type 2 (NF-2 or bilateral acoustic neurofibromatosis). In order to assess clinical presentation of the disease and diagnostic value of Magnetic Resonance Imaging (MRI), the authors retrospectively evaluated the clinical records and the cranial MR studies of 21 patients with neurofibromatosis (18 with NF-1 and 3 with NF-2). Distinctive abnormalities between the two types were found in both clinical presentation and MR studies. Clinically, NF-1 patients presented most often with blindness, while NF-2 patients were deaf and had fewer cutaneous lesions. The evaluation of MR studies showed that NF-1 patients were more likely to be affected with intracranial gliomas, predominantly of the optic pathways. Moreover, foci of prolonged T2 relaxation were frequently observed, primarily in the globus pallidus of the basal ganglia and in the dentate nucleus of the cerebellum. Some of the foci in the globi pallidi exhibited increased signal intensity on T1-weighted images as well. NF-2 patients more frequently presented with bilateral acoustic schwannomas, meningiomas and cerebral white matter foci of prolonged T2 relaxation, but they did not have dentate and basal ganglia lesions. The authors conclude that as a rule the manifestations of NF-1 and NF-2 on cranial MRI are separate and distinct; they do not overlap. MRI is an useful clinical tool for the diagnosis and the follow-up of patients with neurofibromatosis.

Adolescent↗
PubMed1989

[CT study of the cervical spine with intravenous administration of the contrast medium].

Computed tomography (CT) without contrast medium is largely applied to the study of intervertebral disk pathology in the lumbar spine, but has not been widely accepted in the cervical spine, due to technical and anatomical limitations. For these reasons many neuroradiologists still prefer myelography or myelo-CT. CT may yield better results if combined with iv contrast medium injection, which allows a better visualization of disk herniation. This technique is aimed at enhancing the density of the venous plexus which is located close to the intervertebral disk, the vertebral bodies and the neural foramina. A better contrast enhancement is thus obtained between the disk and the spinal cord. The authors' experience is based on 61 patients who underwent contrast enhanced CT; in 22 cases myelography and myelo-CT were also performed. The authors describe their technique and the most frequent CT findings of disk herniation: the typical finding includes a focal hypodensity surrounded by a linear blush, due to a posteriorly dislocated epidural vein. The posterior linear blush alone may be present in few cases. Contrast-enhanced CT is very useful in the study of disk pathology of the cervical spine, even when compared with myelography and myelo-CT, due the increase in the density of epidural plexus it allows. However, the technique must be very accurate if the same results as those of myelo-CT are to be obtained.

Adult↗
PubMed1988

[Diagnostic imaging of renal tumors of small dimensions].

The incidence of small renal tumors (less than cm 3) has increased in the past few years. Reasons for the increased number of reports are related to the contribution of Sonography and Computed Tomography--which enable a greater number of kidneys to be examined and allow a more detailed study of renal parenchyma. In order to assess the diagnostic value and role of the various imaging techniques in this pathology, the authors reviewed all renal tumors observed between 1982 and 1987. Nineteen cases presented with the characteristics of small renal tumors with "solid" findings on both US and CT. Sixteen cases were histologically proven (15 adenocarcinomas, 1 oncocytoma). Three recent, unoperated, cases are included since their features are the same as in the other cases. Metastases and other kinds of tumors (i.e. angiomyolipomas) are not included in this series. Ivp was performed in 14/19 cases; US and CT were always performed. CT proved to be the most sensitive technique, being positive in all cases. Ivp was positive in 9/14 cases (64%) and US in 14/19 (73%). A significant increase in the number of small renal tumors detected was observed, mainly in 1985-1987. This increase is correlated with the increase in the total number of abdominal examinations which US and CT have made possible. Most patients were asymptomatic; in fact, 15/19 cases were incidentally discovered with US and CT of the upper abdomen. US and CT appear to give a substantial contribution to an early diagnosis of small renal tumors, which may have a significant impact on both surgery and prognosis.

Adenocarcinoma↗
PubMed1988

[Computerized tomography of the spine in the evaluation of multiple myeloma].

Computed Tomography (CT) of the spine was performed on 17 patients with myeloma in order to assess the role of the technique in recognizing and evaluating the extent of the lesions. Myelomatous lesions followed two patterns at CT: first of all, multiple focal lesions, whose density is either solid, liquid, or fatty; second, an extensive pattern involving the spongiosa of the vertebra, including the posterior arch. CT detected more lesions than conventional radiology; furthermore, the extent of the lesions was much better demonstrated by CT. CT should thus be performed: a) in case of pain and/or neurological findings in negative radiological examinations; b) to evaluate the extent of myelomatous lesions (mainly in the spine); c) in solitary myeloma CT may be performed on different bone segments with clinical symptomatology but normal X-ray findings.

Humans↗
PubMed1987

Contrast agent nephrotoxicity: comparison of ionic and nonionic contrast agents.

The effects on glomerular and proximal tubular function of an ionic contrast agent (sodium meglumine diatrizoate) and a nonionic agent (iopamidol) were compared in 34 patients with normal renal function. The patients received large doses (2.5 ml/kg body weight) of contrast material for IV digital subtraction angiography. Urine samples, collected before, immediately after, and on the first and third days after digital subtraction angiography, were analyzed for albumin, alanil-aminopeptidase, alpha-glucosidase, and beta-2-microglobulin. The changes noted were mild and of short duration with both contrast agents, despite the high dose given. These results suggest that, at least as far as renal toxicity is measured by these tests is concerned, ionic monomers can be safely used instead of more expensive nonionic media in procedures, such as digital subtraction angiography, that require high doses of contrast material.

Adult↗
PubMed1986

Impact of technology and technique on the performance of the intravenous D.S.A. of the carotid arteries.

Intravenous Digital Subtraction Angiography (i.v. D.S.A.) was performed at the carotid bifurcation level in 259 patients with clinical or physical findings of a Cerebrovascular Insufficiency (C.V.I.). The angiographic examinations have been performed during two different periods, basically differing for the technology of the digital equipment and for the technique used. The personal experience showed how these two factors are important in determining the quality of the image and therefore the accuracy of the i.v. studies. Images of good quality of the common and internal carotid arteries have been obtained in 73% and 54% of the cases of the first period and in 93% and 82% of the cases of the second period. The role of the i.v. D.S.A. in the management of the C.V.I. depends not only upon the quality of the images, but also upon the surgical policy and from the availability of ultrasounds.

Angiography↗