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A Brunetti

Publications and source records attributed to A Brunetti.

At least 37 records · Page 2Linked to original sources
PubMed1999

Temporomandibular ankylosis in the cat: a review of seven cases.

Ankylosis of the temporomandibular joint (TMJ) in the cat is an unusual complication of traumatic lesions involving articular (true ankylosis) or periarticular structures (false ankylosis). Seven cats with true ankylosis of the TMJ (four cases unilateral and three cases bilateral), of which previous trauma had been documented in five cases, were referred to the authors' clinic between September 1991 and October 1996. Radiographic assessment was performed in all cases, using dorsoventral and oblique projections. Five subjects underwent arthroplastic excision of the TMJ and, in the remaining two cases, stretching of the jaws was performed under general anaesthesia. The surgical outcome was satisfactory in all but one case, where partially decreased joint mobility was observed (follow-up time one to five years), but in the two cases where non-surgical treatment was carried out, recurrence of TMJ ankylosis was observed (follow-up time two to five months). In the authors' experience, surgery represents the treatment of choice for TMJ ankylosis in cats. Additional mandibular symphysiotomy can confirm the radiological findings in unilateral cases.

Animals↗
PubMed1999

Frequency encoding for simultaneous display of multimodality images.

UNLABELLED: An original method for simultaneous display of functional and anatomic images, based on frequency encoding (FE), merges color PET with T1-weighted MR brain images, and grayscale PET with multispectral color MR images. A comparison with two other methods reported in the literature for image fusion (averaging and intensity modulation techniques) was performed. METHODS: For FE, the Fourier transform of the merged image was obtained summing the low frequencies of the PET image and the high frequencies of the MR image. For image averaging, the merged image was obtained as a weighted average of the intensities of the two images to be merged. For intensity modulation, the red, green and blue components of the color image were multiplied on a pixel-by-pixel basis by the grayscale image. A comparison of the performances of the three techniques was made by three independent observers assessing the conspicuity of specific MRI and PET information in the merged images. For evaluation purposes, images from seven patients and a computer-simulated MRI/PET phantom were used. Data were compared with a chi-square test applied to ranks. RESULTS: For the depiction of MRI and PET information when merging color PET and T1-weighted MR images, FE was rated superior to intensity modulation and averaging techniques in a significant number of comparisons. For merging grayscale PET with multispectral color MR images, FE and intensity modulation were rated superior to image averaging in terms of both MRI and PET information. CONCLUSION: The data suggest that improved simultaneous evaluation of MRI and PET information can be achieved with a method based on FE.

Brain↗
PubMed1999

Morphological imaging of thymic disorders.

The thymus is a bilobed lymphoid organ the morphology of which varies considerably with age as a result of a process of fatty infiltration occurring after puberty. Although several diseases can arise in the thymic parenchyma, including germ cell and neuroendocrine tumours, primitive epithelial neoplasms (thymomas) are the most common neoplasms and account for almost 10% of mediastinal masses. Thymomas are usually benign but can be locally invasive. Up to 30% of patients with a thymoma have myasthenia gravis, which is more commonly associated with thymic hyperplasia. The latter results in a symmetric diffuse enlargement of the thymus. However, thymic hyperplasia can be histologically found in up to 50% of normal-sized thymuses on computed tomography (CT). CT is much more accurate in detecting thymomas than it is in detecting thymic hyperplasia, although CT findings may be unspecific. CT can be exhaustive in the case of an encapsulated thymoma (65% of all thymomas), which appear as a solid homogeneous mass with a slight contrast enhancement and a well-defined surrounding fat plane. These tumours rarely recur after surgery. CT can also accurately detect a spread through the capsule into the adjacent mediastinal fat, which characterizes invasive thymomas (35%). These, however, are best evaluated by magnetic resonance imaging (MRI). On T1-weighted MR scans the thymus is well delineated against the mediastinal fat, whereas marked inhomogeneity of the signal may appear on T2-weighted images as a result of areas of cystic degeneration in the tumour mass. The superior contrast resolution of MRI and the multiplanar images that can be produced with it are well suited for documenting the mediastinal spread of invasive thymomas. MRI depicts accurately pleural and/or pericardial implants as well as the involvement of great vessels, offering considerable aid in the planning of surgery.

Adult↗
PubMed1998

Reproducibility of intracranial volume measurement by unsupervised multispectral brain segmentation.

To assess the inter-study variability of a recently published unsupervised segmentation method (Magn. Reson. Med. 1997;37:84-93), 14 brain MR studies were performed in five normal subjects. Standard deviations for absolute and fractional volumes of intracranial compartments, which reflect the experimental variability, were smaller than 16.5 ml and 1.1%, respectively. By comparing the experimental component of the variability with the variability observed in our reference database, an estimate of the biological variability of the intracranial fractional volumes in the database population was obtained.

Adolescent↗
PubMed1998

Decreased brain glucose utilization in patients with Cushing's disease.

UNLABELLED: Glucocorticoid hormones affect glucose use in different tissues, and the results of several experimental studies have suggested that glucocorticoids have a central action on cerebral metabolism. PET, using the radiotracer 18F-fluorodeoxyglucose (FDG), permits the measurement of cerebral glucose metabolism. METHODS: To investigate whether cerebral glucose metabolism would be altered in patients with increased plasma glucocorticoid levels, we analyzed the FDG PET studies that were done on 13 patients with Cushing's disease and compared the results with those obtained in 13 age-matched normal control subjects. A second FDG PET scan was performed on 4 patients after surgical removal of the pituitary adenoma. RESULTS: Patients with Cushing's disease had a significant reduction in cerebral glucose metabolism compared with normal controls. In the patients on whom a second PET scan was performed, there was a trend toward increased glucose metabolism on the second scan when comparing pre- and postsurgery values for each patient. CONCLUSION: We suggest that the decreased cerebral glucose metabolism we observed in Cushing's disease is attributable to increased glucocorticoid levels, and we speculate that abnormal cerebral glucose metabolism might contribute to the cognitive and psychiatric abnormalities that are frequently observed in patients with Cushing's disease.

Brain↗
PubMed1997

Unsupervised, automated segmentation of the normal brain using a multispectral relaxometric magnetic resonance approach.

The purpose of this study was the development and testing of a method for unsupervised, automated brain segmentation. Two spin-echo sequences were used to obtain relaxation rates and proton-density maps from 1.5 T MR studies, with two axial data sets including the entire brain. Fifty normal subjects (age range, 16 to 76 years) were studied. A Three-dimensional (3D) spectrum of the tissue voxels was used for automatic segmentation of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) and for calculation of their volumes. Accuracy and reproducibility were tested with a three-compartment phantom simulating GM, WM, and CSF. In the normal subjects, a significant decrease of GM fractional volume and increased CSF volume with age were observed (P < 0.0001), with no significant changes in WM. This multispectral segmentation method permits reproducible, operator-independent volumetric measurements.

Adolescent↗
PubMed1997

White matter lesion detection in multiple sclerosis: improved interobserver concordance with multispectral MRI display.

An assessment of the detectability of white matter lesions and of concordance between observers with different levels of MRI reading experience was performed with comparative evaluation of spin-echo MRI images and of corresponding "multispectral" maps in 16 patients with definite multiple sclerosis (MS). Multispectral maps were obtained by means of a recently described post-processing technique based on the simultaneous display of MRI parameters and a standardized colour scale with red, green and blue coding for relaxation rates R1 and R2 and proton density, respectively. Spin-echo images on films and multispectral maps displayed on a personal computer were randomly rated at 2-month intervals. Interobserver concordance (k-test) was assessed among three readers with different levels of MRI experience (an experienced neuroradiologist, a radiology resident and a neurologist). For multispectral maps we found increased interobserver concordance with the experienced neuroradiologist (multispectral vs conventional images; k = 0.77 vs 0.66 for the radiology resident and 0.66 vs 0.56 for the neurologist), an increased number of detected lesions and decreased reading time. Multispectral maps permit easy detection of MS lesions and may improve interobserver concordance compared with conventional spinecho studies.

Adult↗
PubMed1997

Myelography in the dog with non-ionic contrast media at different iodine concentrations.

Image quality and side effects were evaluated retrospectively in a series of 183 myelographic studies performed with two non-ionic contrast media (iohexol and iopamidol) at different concentrations. Side effects during and following the procedure were recorded. Image quality was assessed using an arbitrary scoring system and statistical analysis was performed with the cross-tabulation test (4 x 2 table) by comparing two groups receiving contrast medium at higher and lower concentrations. No significant differences in side effects were observed between the two groups but the ratings for image quality were significantly higher in the group receiving contrast medium at the higher concentration than in the group receiving the lower concentration. The results suggest that a high concentration of non-ionic contrast media can safely be used in dogs and may improve image quality.

Animals↗
PubMed1997

Advances in brain imaging: a new ethical challenge.

Technical advances in the past 25 years permitted substantial advances in the neuroimaging field, expanding the diagnostic and research potentials and significantly reducing the use of old invasive imaging techniques for research purposes. The safer procedures now available allow acquisition of reference data, morphological assessment and functional characterisation from healthy volunteers. However, enrollment of volunteers is still a sensitive ethical issue. Ethical problems related to informed consent, for both research and diagnostic procedures, in patients with neuropsychiatric disorders represent an additional crucial issue. Furthermore, with both functional and structural neuroimaging studies, there is a theoretical risk of violation of individual privacy. Research in the neuroimaging field should tend to increase the amount of information obtained through appropriate post-processing procedures, including multimodality image fusion, and to limit stress and discomfort.

Brain↗
PubMed1996

Resistance to tomato yellow leaf curl geminivirus in Nicotiana benthamiana plants transformed with a truncated viral C1 gene.

The C1 gene of tomato yellow leaf curl geminivirus (TYLCV) encodes a multifunctional protein (Rep) involved in replication. A truncated form of this gene, capable of expressing the N-terminal 210 amino acids (aa) of the Rep protein, was cloned under the control of the CaMV 35S promoter and introduced into Nicotiana benthamiana using Agrobacterium tumefaciens. The same sequence was also cloned in antisense orientation. When self-pollinated progeny of 19 primary transformants were tested for resistance to TYLCV by agroinoculation, some plants proved to be resistant, particularly in the sense lines. Two such lines were further studied. The presence of the transgene was verified and its expression was followed at intervals. All plants that were resistant to TYLCV at 4 weeks postinoculation (wpi) contained detectable amounts of transgenic mRNA and protein at the time of infection. Resistance was overcome in a few plants at 9 wpi, and in most at 15 wpi. Infection of leaf discs derived from transgenic plants showed that expression of the transgene correlated with a substantial reduction of viral DNA replication. Cotransfections of tobacco protoplasts demonstrated that inhibition of viral DNA replication requires expression of the truncated Rep protein and suggested that the small ORF C4, also present in our construct, plays no role in the resistance observed. The results obtained using both transient and stable gene expression systems show that the expression of the N-terminal 210 aa of the TYLCV Rep protein efficiently interferes with virus infection.

Agrobacterium tumefaciens↗
PubMed1996

Human diabetes associated with defects in nuclear regulatory proteins for the insulin receptor gene.

The control of gene transcription is mediated by sequence-specific DNA-binding proteins (trans-acting factors) that bind to upstream regulatory elements (cis elements). We have previously identified two DNA-binding proteins that specifically interact with two unique AT-rich sequences of the 5' regulatory region of the insulin receptor gene which have in vivo promoter activity. Herein we have investigated the expression of these DNA-binding proteins in cells from two unrelated patients with insulin resistance and non-insulin-dependent diabetes mellitus. In these patients, the insulin receptor gene was normal. In EBV-transformed lymphoblasts from both patients, insulin receptor mRNA levels and insulin receptor expression were decreased. The expression of nuclear-binding proteins for the 5' regulatory region of the insulin receptor gene was markedly reduced, and this defect paralleled the decrease in insulin receptor protein expression. These studies indicate that DNA-binding proteins to the regulatory region of the insulin receptor gene are important for expression of the insulin receptor. Further, they suggest that in affected individuals, defects in the expression of these proteins may cause decreased insulin receptor expression and insulin resistance.

Cell Extracts↗
PubMed1996

Different thallium-201 single-photon emission tomographic patterns in benign and aggressive meningiomas.

To evaluate the possibility of preoperatively obtaining an index of aggressiveness for intracranial meningiomas, we prospectively studied 22 patients with computed tomographic or magnetic resonance imaging evidence of meningeal tumour, using single-photon emission tomography (SPET) of the brain and thallium-201 (201Tl). On a brain-dedicated SPET scanner, a rapid acquisition protocol with early, short scans was started simultaneously with the intravenous administration of 111 MBq 201Tl, covering the initial intratumoral distribution of the tracer. Twenty minutes post injection, a delayed SPET scan was also obtained. On the reconstructed and attenuation-corrected images we calculated the 201Tl concentration in tumour and normal contralateral brain tissue, and compared intratumoral tracer concentration in the initial and the final part of the rapid acquisition protocol. Benign and malignant meningiomas were classified as such based on histological examination. In malignant lesions, the ratio of the 201Tl concentration at 2-4 min post injection to that at 14-16 min was found to be significantly higher than in non-aggressive neoplasms (mean+/-1 SD: 1.14+/-0.31 and 0.56+/-0.13, respectively, P <0.01). Conversely, in the delayed scan, most lesions showed high tracer concentration, and the two groups could not be distinguished. In addition, three recurrent meningiomas displayed the same imaging behaviour as the malignant group, i.e. had similar 201Tl concentration values at 2-4 and at 14-16 min. Our findings suggest that the comparative assessment of intratumoral 201Tl concentration at 2-4 and at 14-16 min post injection could provide a fast, simple method to differentiate preoperatively intracranial meningiomas with different biological behaviour.

Female↗
PubMed1996

Functional characterization of brain tumors: an overview of the potential clinical value.

Early detection and characterization are still challenging issues in the diagnostic approach to brain tumors. Among functional imaging techniques, a clinical role for positron emission tomography studies with [18F]-fluorodeoxyglucose and for single photon emission computed tomography studies with [201Tl]-thallium-chloride has emerged. The clinical role of magnetic resonance spectroscopy is still being defined, whereas functional magnetic resonance imaging seems able to provide useful data for presurgical localization of critical cortical areas. Integration of morphostructural information provided by computed tomography and magnetic resonance imaging, with functional characterization and cyto-histologic evaluation of biologic markers, may assist in answering the open diagnostic questions concerning brain tumors.

Brain Neoplasms↗
PubMed1996

Morphologic alterations in the cilia of a cat.

Based upon ultrastructural findings and computed tomography, a presumptive diagnosis of feline primary ciliary dyskinesia was made in a 2.5-year-old cat. The cat demonstrated morphologic alterations in the ultrastructure of oviductal cilia. In the oviduct, axonemal abnormalities were detected in 132 (20%) of 660 cross-sectioned cilia. The main ultrastructural ciliary defects were a lack of central microtubules, transposition of peripheral doublets to the center of the axoneme, supernumerary microtubules, and morphologic abnormalities of peripheral doublets. Computed tomography of the chest was consistent with early lesions of bronchiectasis, suggesting chronic stagnation of respiratory secretions, attributed to abnormal function of respiratory cilia. Specifically, the cranial branches of the cat's bronchi were wider and thicker than those of five healthy controls. Foci of pleural thickening and interstitial enlargement were also observed.

Animals↗
PubMed1996

Evaluation of brain perfusion with high resolution single photon emission tomography in the diagnosis of brain death.

Nuclear Medicine studies performed with tomographic acquisition and tracers such as Technetium-99m hexamethyl-propyleneamine oxime (99mTc-HMPAO) are able to assess cerebral blood flow. A case is reported of a patient with a large intracranial tumor, of possible pituitary origin, with a clinical and electroencephalographic suspicion of brain death. The patient had endocrinous-metabolic impairments for a history of impotence, since 18 months, and diabetes insipidus with a urine output of 350 ml/hr in the first 24 hours from the clinical suspicion of brain death. Due to the endocrinous-metabolic impairments, according to Italian law, it was necessary to confirm the diagnosis of brain death by performing a study able to assess cerebral blood flow. A single Photon Emission Tomography (SPET) scan was performed after the intravenous administration of 99mTc-HMPAO using a high resolution, brain dedicated device. No tracer uptake was evident in cerebral, cerebellar and brain stem structures. The cerebral blood flow study by SPET confirmed the diagnosis of brain death and made the organ transplant possible in a short period of time. High resolution SPET studies are useful to confirm the diagnosis of brain death when there are factors that can influence clinical and electroencephalographic signs, reducing time to authorise the organ explant.

Adult↗
PubMed1995

1H MR spectroscopy in patients with metastatic brain tumors: a multicenter study.

In a cooperative study involving six clinical MR centers, localized 1H MR spectroscopy was used to characterize untreated metastatic brain tumors (40 cases, 45 lesions). Cubic volumes (3.4 or 8 cm3) filled for more than 50% by metastatic brain tissue were examined by single-voxel double spin echo MRS, by using chemical shift selective imaging (CHESS) pulses for water suppression and TE = 135 ms. Choline (Cho), creatine (Cr) and N-acetyl aspartate (NAA) levels in brain metastases of mammary carcinoma (n = 13), lung cancer (n = 11) and melanoma (n = 10) were similar. Metastasis NAA/Cho signal intensity ratio varied between 0.00 and 1.17, compared with 2.68 +/- 0.56 (SD) in lobus occipitalis and 1.94 +/- 0.63 in corpus nuclei caudati region (P < 0.0001, both). 1H MR spectroscopy, although not suited to recognize the primary tumor of metastases, could serve as a clinical test for excluding (metastatic) tumor as cause of solitary focal brain disorders that are hard to diagnose with current imaging methods.

Adult↗