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Biomedical subjects

G M Giannatempo

Publications and source records attributed to G M Giannatempo.

At least 19 recordsLinked to original sources
PubMed2006

Brain MRI white matter lesions in migraine patients: is there a relationship with antiphospholipid antibodies and coagulation parameters?

Brain magnetic resonance imaging (MRI) studies in migraine patients have demonstrated lesions consisting of focal regions of increased signal intensity within the white matter. Antiphospholipid antibodies are known to have a role in many diseases including migraine. The aim of the present study was to ascertain the relationship between MRI-visualized cerebral focal hyperintense lesions and serum antiphospholipid antibody levels, as well as blood coagulation parameters in migraine patients. One hundred and two (77 females, 25 males, mean age 33.8 +/- 11.1) consecutive migraine patients and a control group of 94 (70 females, 24 males, mean age 33.2 +/- 10.8) healthy subjects were enrolled. All individuals underwent brain MRI. Complete blood examinations, autoantibodies, antiphospholipids antibodies including anticardiolipin and lupus anticoagulant (aCL, LAC), antithrombin III, Protein C and S serum levels were ascertained in the subjects who presented white matter lesions on MRI. Twenty-seven (26.4%) migraine patients and six (6.3%) healthy subjects in the control group showed focal regions of increased intensity signal within cerebral white matter (odds ratio 5.3, 95% CI: 1.98-16.36). In migraine patients with white matter lesions, antiphospholipid antibodies were not detected and serum levels of antithrombin III, and proteins C and S were normal. White matter lesions in migraine patients are fairly common. This finding is not associated with antiphospholipid antibodies or abnormal coagulation parameters. The significance of such lesions at present remains unclear.

Adult↗
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↗
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↗
PubMed2001

Cerebellar metastasis as a unique presenting feature of gastric cancer.

Gastric cancer is often diagnosed in middle-aged patients undergoing upper gastrointestinal endoscopy for abdominal complaints or constitutional symptoms, such as dyspepsia, vomiting or anorexia, weight loss, anemia, jaundice, and ascites. Sometimes, all of these symptoms may be absent, and gastric cancer is diagnosed after detection of metastases to target organs, such as the liver or lung. In a few rare cases, however, even these metastatic localizations may be absent, and clinical signs are only represented by atypical symptoms caused by neurologic metastatic involvement. We report an exceptionally rare case of gastric cancer in which the only presenting symptoms were headache and dizziness caused by a single cerebellar metastasis.

Carcinoma, Signet Ring Cell↗
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

Global skeletal uptake of technetium-99m methylene diphosphonate in female patients receiving suppressive doses of L-thyroxine for differentiated thyroid cancer.

This study was carried out in order to investigate the possible detrimental effects on bone of levothyroxine (l-T4) suppressive therapy in female patients who had undergone surgery for differentiated thyroid cancer (DTC). Twenty female (14 premenopausal and 6 postmenopausal) patients receiving l-T4 suppressive therapy for DTC were studied. The sample was selected in such a way as to avoid factors influencing bone metabolism other than l-T4. All patients were monitored by sensitive thyroid-stimulating hormone, free triiodothyronine and free thyroxine assays throughout the follow-up. Nineteen healthy (12 premenopausal and 7 postmenopausal) matched women served as controls. In all subjects bone turnover was evaluated by the measurement of global skeletal uptake of technetium-99m methylene diphosphonate (GSU); bone mineral density (BMD) was measured by quantitative computed tomography at the lumbar spine (LS) and by dual-energy X-ray absorptiometry both at the LS and at three femoral sites: the femoral neck, Ward's triangle and the greater trochanter. No significant difference was found in either GSU or BMD between patients (treated for an average period of 68 months) and controls in the whole sample or in any subgroup. Furthermore, no correlations were found between either GSU or BMD and the duration of therapy, daily doses of l-T4 or results of thyroid function tests. Our data show that carefully monitored l-T4 therapy does not influence skeletal turnover (directly reflected by GSU) or the bone density of the spine and femur.

Absorptiometry, Photon↗
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↗
PubMed1997

Skeletal involvement in female acromegalic subjects: the effects of growth hormone excess in amenorrheal and menstruating patients.

Bone involvement is a common clinical feature in acromegalic patients, though previous studies gave divergent results possibly because of the different gonadal status of the patients studied. To study the influence of estrogen milieu in these patients, we evaluated 23 acromegalic patients with active disease, subdivided into two groups: menstruating and amenorrheal patients, comparable for duration and activity of disease. Forty-two matched women served as controls. Skeletal involvement was studied by measuring: (a) the main biomarkers of bone turnover: serum alkaline phosphatase total activity (AP), bone GLA protein (BGP), serum carboxy-terminal propeptide of type I collagen (PICP), serum type I cross-linked N-telopeptide (ICTP), and urinary pyridinoline and deoxypyridinoline corrected for creatinine (Pyr/Cr, D-Pyr/Cr) and urinary calcium/creatinine ratio (Ca/Cr); (b) bone mineral density (BMD), as measured by quantitative computed tomography both at lumbar spine and distal radius, and by dual X-ray absorptiometry both at lumbar spine and at three femoral sites (Ward's triangle, femoral neck, and great trochanter). AP, BGP, ICTP, Pyr/Cr, D-Pyr/Cr were significantly higher in patients than in controls, independent of the menstrual pattern. Higher PICP levels were found in the whole group and in menstruating acromegalics when compared with control women; no difference was found in amenorrheal patients, who in turn showed higher urinary Ca/Cr values. When patients were considered all together, BMD at spine, femoral neck, and trochanter was higher than in controls. In contrast, when the gonadal status was taking into account and, menstruating and amenorrheal subjects were considered separately, BMD at spine, but not in other sites, was significantly higher in menstruating patients than in controls. In contrast, no difference of BMD values at any site was observed between amenorrheal patients and controls. The mean BMD Z scores allowed us to detect an unequal involvement of different skeletal sites. Our results show that bone turnover is increased in acromegalic women and suggest that GH anabolic effect on bone is more evident in the presence of estrogens and that different skeletal sites may be affected differently by hormone excess.

Acromegaly↗
PubMed1997

[Magnetic resonance angiography of the vessels of the neck: the optimization of a dynamic technic during the rapid infusion of a paramagnetic contrast medium].

INTRODUCTION: A new noninvasive technique, dynamic Magnetic Resonance Angiography (MRA) during rapid infusion of paramagnetic contrast medium, has been recently developed for the study of neck vessels. This study was carried out to optimize technical parameters. MATERIALS AND METHODS: Twenty healthy volunteers (10 men and 10 women; age range: 25 to 50 years) were examined with a 1.5 T MR unit equipped with fast imaging software and a dedicated coil. Dynamic MRA was performed using fast spoiled gradient recalled (fast SPGR) sequences acquired on the coronal plane 13 s after contrast medium injection. Imaging parameters were: Echo Time (TE): 1 ms, Repetition Time (TR): 8 ms, flip angle: 60 degrees, matrix 256 x 128, number of excitations: 1, field of view: 18 x 13 cm, number of partitions per slab: 28, slice thickness: 1 mm, acquisition time: 32 s. A dose of .2 mmol/kg of paramagnetic contrast medium was administered with an MR compatible automatic injector, at a speed rate of 1.5 ml/s. Angiographic images were postprocessed with the maximum intensity projection (MIP) and targeted MIP algorithms. RESULTS: Using the above parameters and rapid contrast medium injection, the carotid arteries on the coronal plane (including the vessels from the proximal aspect of the common carotid arteries to the intracranial tract of the internal carotid arteries) in 18 cases. In the other two cases the tortuosity and the position of the carotid arteries on two different planes, prevented their complete visualization. The vertebral arteries were completely demonstrated in 50% of the investigated population. Partial or total overlapping of jugular veins did not affect the recognition of the carotid vessels in 10 cases, also with targeted MIP postprocessing. DISCUSSION: The vascular semiology of dynamic gadolinium enhanced MRA seems to be closer to that of conventional angiography than of conventional MRA, likely due to the same modality of vessel depiction, based on contrast medium administration. Flow artifacts, the major pitfall of conventional MRA causing signal void and overestimation of stenosis grade, are not frequent in dynamic MRA. CONCLUSIONS: Gadolinium enhanced dynamic MRA ensures panoramic and high resolution angiographic-like depiction of the neck vessels, providing rapid and excellent definition of vascular morphology. Thus dynamic MRA appears to be a substantial alternative to conventional MRA and conventional angiography.

Adult↗
PubMed1997

Long-term in vitro precision of single slice peripheral Quantitative Computed Tomography (pQCT): multicenter comparison.

In a multicenter evaluation the precision and stability of single slice peripheral Quantitative Computed Tomography (pQCT) systems were assessed. Compared to central Europe the peripheral QCT device is also widely used in the Italian health care system. Phantoms were measured frequently on each machine in four pQCT scanners over a two-year period using an identical automated software program. Intrasite and intersite phantom mineral densities, expressed in units of mg/cm3, were analyzed and examined. The short and long term precision were estimated from the consistency of these measurements using the root mean square error and expressed as coefficient of variation in percent (% CV). Short term precision was good (mean intrasite coefficient of variation (CV) 0.21 +/- 0.056 standard deviation (SD)). Intersite measurements of a single phantom revealed differences between machines of the same type of not more than 2.9 mg/cm3. At four sites frequent phantom measurements revealed a mean CV of 0.18% (range 0.12-0.28). No significant changes in the regression slopes (drift of the machine versus time) were observed. We conclude that the in vitro precision and stability of the single slice pQCT systems are sufficiently high and unlikely to negatively affect the in vivo precision.

Absorptiometry, Photon↗
PubMed1996

[The reduction of ferromagnetic artifacts by using a fast-spin-echo sequence in the postoperative assessment of degenerative diseases of the cervical spine].

This study was aimed at investigating if fast spin echo (FSE) pulse sequences can increase the diagnostic capabilities of MRI in the patients with degenerative disease of the postoperative cervical spine, considering their lower magnetic susceptibility than that of conventional spin echo (SE) sequences. The patient population consisted of 15 patients submitted to diskectomy after Cloward and Caspar. MR images were acquired with a 1.5-T unit (Signa, General Electric) with T2-weighted FSE versus conventional T1- and T2-weighted SE images. Thanks to fewer metallic artifacts, FSE images of the postoperative cervical spine yielded more pieces of information than conventional SE sequences in demonstrating the spine and its content. The best results were obtained in the patients with canal stenosis (8 patients) and myelomalacia (2 patients). In addition, the myelographic effect, another major semiologic feature of the FSE technique, provided further diagnostic information in these patients. Moreover, shorter examination times resulted in better patients tolerance, especially in those with recent surgery. Finally, reducing motion, blood flow or CSF flow artifacts definitely improved FSE image quality.

Aged↗
PubMed1996

[Magnetic resonance myelography with a fast-spin-echo sequence].

A major application of Magnetic Resonance Imaging (MRI) consists in the "myelographic effect", characterized by high signal intensity of the CSF, which permits to visualize spinal subarachnoid spaces and nerve root sheaths. Such new ultrafast pulse sequences as fast spin echo (FSE) further enhance CSF high signal intensity. In addition, suppressing background with the fat suppression technique and with maximum intensity projection (MIP), a particular algorithm already used in MR angiography, FSE sequences yield 3D myelography-like images. Our study was aimed at assessing the clinical role and the reliability of this technique. Our preliminary experience is based on 21 patients with pain in the lower back and legs and on 5 healthy volunteers; all the myelography-like images were obtained with a 1.5-T MR system (Signa, General Electric). The parameters for FSE myelography-like images included: TR = 6000, TE = 200, ETL = 32, thickness = 3 mm, matrix = 256 x 224, Nex = 4, FOV = 20 cm, fat presaturation, no phase wrap, acquisition time = 2 min 58 s. MR myelography sequences were acquired after a standard FSE T1/T2-weighted exam. MR-myelography results confirmed the diagnosis of disk herniation made on conventional T1/T2-weighted images, especially in thecal sac compression and/or amputation of nerve root sheaths. MR myelography appeared to be especially useful in migrated disk herniation or in abnormal origin of nerve roots. Moreover, it allowed full and panoramic visualization of the subarachnoid spaces and excellent definition of the thecal sac, nerve roots and nerve root sheaths. In one patient only movement artifacts affected image quality. To conclude, even though it fails to yield any functional information, MR myelography appears to be an easy, rapid and noninvasive support to conventional MRI of the lumbar spine, to replace conventional myelography.

Female↗
PubMed1996

[Fast spin echo imaging of vertebral metastasis: comparison of fat suppression techniques (FSE-CHESS, STIR-FSE)].

PURPOSES: To investigate the capabilities of fast spin echo (FSE) sequences in diagnosing spinal metastases and to compare two fat-suppression techniques: CHESS (chemical shift selective saturation) and STIR (short T1 inversion recovery). Fat suppression is recommended with FSE sequences because on them, different from conventional spin echo (SE) sequences, fat has high signal intensity in both T1 and T2 weighting, masking such high-signal bone lesions as metastases. METHODS: Ninety metastatic lesions in 32 patients were studied with T1-weighted SE and T2-weighted FSE sequences with and without fat suppression (FSE-CHESS and STIR-FSE). Quantitative analyses (metastasis size, signal intensity, margins and conspicuity) and qualitative analyses (artifacts and fat saturation homogeneity) were carried out of both fat-suppression sequences. Signal-to-noise (S/N) and contrast-to-noise (C/N) ratios were calculated in 20 metastatic lesions. The results were analyzed with the chi 2 method and the paired t-test. RESULTS: Both fat-suppression FSE sequences were more sensitive to focal lesions (100%) than T1-weighted SE sequences (96.6%). Lesion signal was higher than that of surrounding bone in 95.5% of fat-suppressed images, which facilitated the recognition of spinal metastases. On the contrary, conspicuity was higher (73.3%) and the margins more definite (68.8%) on T1-weighted SE than on T2-weighted FSE sequences. Fat suppression was more apparent on STIR-FSE than on FSE-CHESS sequences, even with no significant difference in C/N ratio. CONCLUSION: Both STIR-FSE and FSE-CHESS sequences are rapid and useful techniques to obtain fat saturation in FSE images. CHESS saturation is selective on fat signal, while STIR suppresses the signal of all the substances with the same short T1 as fat.

Adipose Tissue↗