Biomedical subjects

G Dal Pozzo

Publications and source records attributed to G Dal Pozzo.

At least 19 recordsLinked to original sources

PubMed1997

Possible pathogenetic role of activated platelets in the primary antiphospholipid syndrome involving the central nervous system.

Neurological disorders occurring in the primary antiphospholipid syndrome (neuro-PAPS) have not yet been completely understood. Platelet activation has been suggested to play a crucial role in the pathogenesis of hemostatic disorders in the antiphospholipid syndrome, but no association with neuro-PAPS has been investigated so far. Therefore, we investigated 16 patients with PAPS by flow cytometry in the presence of circulating activated platelets as defined by the surface expression of activation-dependent glycoprotein CD62. In addition, the relationship among activated platelets and anticardiolipin antibodies (aCL) was evaluated. Compared to normal subjects CD62 was found significantly increased in these patients. Furthermore, a significantly increased percentage of CD62-positive platelets was found in the neuro-PAPS group (nine patients) compared to the non-neuro-PAPS patients (seven subjects). On the contrary, no significant difference was found between the two groups with regard to aCL IgG and platelet number. Furthermore, within the neuro-PAPS group, no difference was evidenced, in the CD62-positive platelet percentage, between the four subjects with thrombocytopenia and the five with the normal blood platelet count. Similarly, neuro-PAPS subjects with previous peripheral arterial and/or venous thrombosis did not show a significantly more elevated level of CD62-positive platelets. Finally, a linear correlation was found between the aCL IgG level and the CD62-positive platelet percentage in all the patients and, more significantly, in the neuro-PAPS group, but not within the non-neuro-PAPS patients. Our data demonstrate that circulating activated platelets are detectable by flow cytometry in the majority of PAPS patients and suggest the existence of a relationship among activated platelets, aCL, and neurological disease that patients affected by PAPS might undergo.

Adult↗

PubMed1997

Magnetic resonance imaging of cerebral associative white matter bundles employing fast-scan techniques.

Rapid scan techniques have introduced new sequence parameters as well as novel contrast concepts into everyday magnetic resonance imaging (MRI). In particular contrast characteristics of fast-spin echo (FSE) sequences showed some significant differences when compared to conventional spin echo images. The purpose of this work was to demonstrate the capabilities of FSE MRI in identifying and characterizing the in vivo anatomy of the main cerebral associative systems. Between March and November 1995, 20 healthy adult volunteers (12 males, 8 females, mean age 35 years) were submitted to a cranial MRI examination (1.5 Philips Gyroscan NT). In all cases axial and coronal 2-dimensional FSE T2-weighted and 2-dimensional inversion recovery FSE T1-weighted images were obtained. All MRI images were examined by a neuroradiologist (G. Dal Pozzo) for the depiction of the following compact white matter fiber bundles: anterior commissure, corpus callosum, superior fronto-occipital fasciculus, cingulum, fornix, mammillothalamic tract, uncinate fasciculus, superior and inferior longitudinal fasciculus. All these associative pathways could be well identified on T2-weighted images due to a lower signal intensity with respect to the surrounding white matter. On T1-weighted images only the corpus callosum, the anterior commissure and the fornix could always be identified. Correlation with myelin-specific colorations (Luxol fast blue stains) in anatomic atlases and a review of the literature on the myelinization process during infancy indicate that the short T2 relaxation times of the aforementioned cerebral associative systems may be due to heavy myelination and high fiber density. The correct visualization of interintrahemispheric associative white matter fiber bundles may play an important role in white matter disorders like dys- and demyelinating diseases and in the spreading of vasogenic edema and/or tumor being useful for their staging.

Adult↗

PubMed1995

MRI of spinal epidural lymphoma.

We reviewed the MRI features in eight patients with spinal epidural lymphoma (clinically primary in 4 patients); one patient had multiple lesions. The cervical spine was involved in one patient, the thoracolumbar spine in 5 and the sacrum in two. Mean longitudinal extension of the epidural lesion was 2.6 vertebral segments. The tumours were homogeneously isointense with the spinal cord on T1-weighted images and isointense or hyperintense on proton-density and T2-weighted images. The spinal cord was compressed in four patients but showed signal changes in only one. In five patients the lesions communicated through the intervertebral foramina with paravertebral soft tissue masses. In all but one of the patients diffuse signal changes in the vertebral body marrow consistent with osteolytic or osteoblastic changes were identified adjacent to or at distance from the epidural lesion. Vertebral collapse was observed in two patients.

Adult↗

PubMed1995

MRI of congenital Foix-Chavany-Marie syndrome.

MRI findings of bilateral central macrogyria allowed the diagnosis of a congenital variant of Foix-Chavany-Marie syndrome in four patients aged between 13 and 32 years, with facio-pharyngo-glosso-masticatory central diplegia, mental retardation and seizures.

Adolescent↗

PubMed1994

Quantitation of brain perfusion with 99mTc-bicisate and single SPECT scan: comparison with microsphere measurements.

This study describes and validates in a preliminary manner a method to measure the steady-state influx constant (Ki) of 99mTc-bicisate with one single photon emission computed tomography (SPECT) scan. The method is based on the analysis of the arterial concentration of the radioactivity. The results of this quantitation procedure were compared with regional CBF (rCBF) measurements made using 99mTc-microspheres (MI). Two quantitative indexes of perfusion, fractional brain uptake (FBU) and normalized (with cerebellum) brain uptake (NBU), were also evaluated. Two SPECT studies were performed on seven cardiovascular patients who had no signs of neurological disease. In the first of these, 99mTc-bicisate was used, while in the other, which was performed 2 days later, MI were injected into the left heart ventricle. The values of the FBU, NBU, and Ki of 99mTc-bicisate were calculated in several gray and white matter brain regions of interest (ROIs) and compared with the rCBF values measured with MI in coupled ROIs. Mean FBU values were 0.00008 +/- 0.00002 and 0.00004 +/- 0.00001 in the gray and the white matter, respectively. Mean NBU values were 0.99 +/- 0.04 and 0.54 +/- 0.05, mean Ki values were 0.36 +/- 0.06 and 0.19 +/- 0.03 ml g-1 min-1 and mean rCBF values were 0.51 +/- 0.04 and 0.27 +/- 0.04 ml g-1 min-1 in gray and white matter, respectively. Analysis of variance of the regression gave different F values for the regressions with rCBF of FBU (F = 19, n = 126), NBU (F = 289, n = 112), and Ki (F = 117, n = 126).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1993

Effectiveness of the Short TI Inversion Recovery (STIR) sequence in MR imaging of intramedullary spinal lesions.

A Short TI Inversion Recovery (STIR) sequence with spin-echo data collection was compared to a conventional cardiac gated long TR spin-echo (SE) sequence for detecting intramedullary signal abnormalities. The cervical (n = 48), cervico-thoracic (n = 1), and thoraco-lumbar (n = 18) spinal cord was imaged in a sagittal plane with a 0.5 T (n = 61) or 1.5 T (n = 6) MRI unit in 67 patients with clinical evidence of myelopathy of different etiologies (e.g., multiple sclerosis, trauma, herniated intervertebral disk, spondylosis, etc.). In all patients, ungated double or quadruple echo STIR images (TR 1000-1400 msec, TI 100 msec, TE 30-60 or 30-60-90-120 msec) were compared with cardiac gated long TR (1400-2100 msec), double echo (30-100, 50-100, or 50-150 msec) SE images with first order flow compensation for the second echo. Although STIR images appeared "noisier" than long TR SE images, they showed fewer ghost artifacts. In 55 patients, single or multiple, focal or diffuse, hyperintense areas within the spinal cord were observed on both long TR SE and (magnitude reconstructed) STIR images. Lesion conspicuity was better on the STIR images in 25 patients, better on the SE images in 14 patients, and equal in 16. STIR sequence provides a valuable alternative to gated long TR SE sequence for the MRI investigation of intramedullary spinal lesions.

Adolescent↗

PubMed1993

Acute spinal trauma: prognostic value of MRI appearances at 0.5 T.

Thirty-two patients with post-traumatic myelopathy were examined with a 0.5 T MRI system within 4 days of injury and the MRI findings analysed with respect to the immediate and residual functional deficit and (in 20 patients) the MRI appearances of the spinal cord in the chronic phase. In the acute phase a normal spinal cord was associated with only slight clinical deficit in four patients. Signal abnormalities in the spinal cord at the site of trauma were identified on T2-weighted spin-echo or T2*-weighted gradient-recalled echo images in 28 patients. The 12 most functionally impaired patients showed focal low signal suggestive of intramedullary haemorrhage: the other 16 had homogeneous high signal consistent with diffuse oedema. Swelling of the spinal cord and mild persistent cord compression following reduction were noted in 17 and 26 patients respectively. All patients were treated conservatively other than undergoing surgical decompression. Four died of complications. No patient with low signal in the spinal cord on initial MRI showed significant clinical improvement. Five whose spinal cord was hyperintense remained unchanged, whereas nine made a significant recovery, as did all patients with normal-appearing spinal cords. Cord compression on the initial examination was not relevant to clinical outcome. Intramedullary scars were identified at follow-up in 18 patients and were more extensive in those with haemorrhagic acute lesions. Haemorrhagic contusion of the spinal cord can be demonstrated in the acute phase with midfield MRI and is a valuable predictor of the functional outcome in patients with traumatic myelopathy.

Acute Disease↗

PubMed1993

Role of the mandibular first molar in the development of the supraorbital region in apes and humans.

Our previous studies in apes and humans have demonstrated that the development of the supraorbital ridge is a direct consequence of masticatory forces. The smaller the power arm/load arm ratio of the mandible, the greater the force exerted by the temporalis muscle and the larger the supraorbital ridge. The purpose of the present study is to further elucidate the role of the masticatory apparatus, in particular the role of the first mandibular molar. Measurements of the size of the supraorbital ridges in ape skulls and in human skulls from Tuscany, Italy and St. Lawrence Island, Alaska, were determined using parasagittal CAT scans as in our previous studies. For the purpose of this study, the mesio-distal and buccolingual dimensions of the first molar were measured from the actual tooth in all cases. Statistical analysis shows a positive correlation between the mesio-distal dimension of the mandibular first molar and the size of the ridge in humans (r = 0.61, p < 0.005) and in apes (r = 0.79, p < 0.01), which explains much of the variation in the size of the supraorbital ridge, 37% (0.61(2)) in humans and 62% (0.79(2)) in apes. The role of the mandibular first molar differs in humans versus apes because of differences in masticatory mechanics.

Adult↗

PubMed1993

Cine-MR imaging of aqueductal CSF flow in normal pressure hydrocephalus syndrome before and after CSF shunt.

Reproducibility of the aqueductal CSF signal intensity on a gradient echo cine-MR sequence exploiting through plane inflow enhancement was tested in 11 patients with normal or dilated ventricles. Seven patients with normal pressure hydrocephalus (NPH) syndrome were investigated with the sequence before and after CSF shunting. Two patients exhibiting central flow void within a hyperintense aqueductal CSF improved after surgery and the flow void disappeared after shunting. One patient with increased maximum and minimum aqueductal CSF signal as compared to 18 healthy controls also improved and the aqueductal CSF signal was considerably decreased after shunting. Three patients with aqueductal CSF values similar to those in the controls did not improve, notwithstanding their maximum aqueductal CSF signals decreasing slightly after shunting. No appreciable aqueductal CSF flow related enhancement consistent with non-communicating hydrocephalus was found in the last NPH patient who improved after surgery. Cine-MR with inflow technique yields a reproducible evaluation of flow-related aqueductal CSF signal changes which might help in identifying shunt responsive NPH patients. These are likely to be those with hyperdynamic aqueductal CSF or aqueductal obstruction.

Adolescent↗

PubMed1992

Multiple lesions in cerebral white matter in two young adults with thoracic extramedullary tumours.

Cranial MRI showed multiple lesions in white matter that were thought to be consistent with multiple sclerosis in two young adults presenting with symptoms of progressive myelopathy. MRI of the cervicothoracic spine around one and two years after onset showed the myelopathy to be due to mid-thoracic tumours. The tumours (an extradural meningioma and intradural neuroma) were resected with complete resolution of myelopathy in one patient but no recovery in the other. Spinal MRI (or myelography) should be performed in young patients presenting with signs of progressive myelopathy even when cranial MRI shows a picture typical of multiple sclerosis.

Adult↗

PubMed1992

Magnetic resonance imaging of degenerative diseases of the central nervous system.

MRI enables a better assessment than CT of the bulk loss, i.e. atrophy, which is a characteristic feature of all the degenerative diseases of CNS, at least in their advanced phases. Moreover, in several of these disorders, proton density, balanced and T2 weighted MR images can show symmetric areas of abnormally low or high signal intensity in the deep gray nuclei or white matter. Since these signal abnormalities are not specific of degenerative diseases of the CNS, their shape and distribution have to match those of the histopathological changes characteristic of each disease, before they could represent useful ancillary signs. Combination of the above MRI findings with appropriate clinical and laboratory features will however be crucial to the diagnosis in any single case.

Adult↗

PubMed1992

Rhabdomyosarcoma of the petrous ridge. CT and MR imaging in an atypical case with multiple cranial nerve palsy.

The CT and MR findings are reported in a case of biopsy proven rhabdomyosarcoma of the skull base. The tumor presumably originated in a pneumatized petrous ridge and had an atypical presentation of multiple cranial nerve palsy. The lesion exhibited a soft tissue density and a nonexpansile bone destruction on unenhanced CT. On MR imaging the lesion showed homogeneous intermediate signal intensity on T1 weighted images and a high signal intensity on proton density and T2 weighted images. The scanty literature on CT and MR features of rhabdomyosarcoma of the head and neck is reviewed.

Child, Preschool↗

PubMed1991

Intrathecal synthesis of free immunoglobulin light chains and IgM in initial multiple sclerosis.

We studied the intrathecal synthesis of free kappa, free lambda immunoglobulin light chains and of IgM in 33 consecutive patients with possible or probable MS at the time of their first diagnosis. Nineteen patients presented free kappa or lambda light chain bands in CSF after agarose isoelectric focusing, protein transfer to nitrocellulose and immunostaining with specific antisera. Nineteen patients had increased CSF levels of free kappa light chains as measured with a competitive ELISA. Fourteen had an increased IgM index, as evaluated with a sandwich ELISA. Twenty-six patients displayed CSF oligoclonal IgG bands in CSF and 25 had cerebral magnetic resonance imaging lesions suggestive of MS. The local production of free immunoglobulin light chains and IgM is often detected in the CSF of patients with early MS.

Adolescent↗

PubMed1991

[Congenital toxoplasmosis. Report of a case treated with spiramycin in the 24th week of pregnancy].

The Authors present one case of congenital toxoplasmosis; it was sustained by a primary maternal infection, contracted at the XXIII week of gestation. Even if we started the treatment with spiramycin at the XXIV week of gestation, both the prenatal ultrasound examination of the fetus, and the postnatal investigation of the newborn, showed that the young patient was affected by a severe form of congenital toxoplasmosis.

Female↗

PubMed1991

[The incidence of disk changes in volleyball players. The magnetic resonance findings].

In order to evaluate the to potential hazards related to athletic functional overload on the intervertebral disk we studied with MRI the incidence of intervertebral disk abnormalities in a group of 45 volunteers who had been playing professional volleyball for 3-7 years. As a control group we examined with MRI 30 professional swimmers as well. Among the volley-ball players the incidence of intervertebral disk alterations was 44.4%; they were represented by 8 cases of disk degeneration, 11 cases of bulging and 9 disk herniations (in 8 patients the simultaneous presence of more than one lesion was observed). In the control group the incidence of such lesions was 20%. The obtained results were correlated with the clinical findings and the age of the athletes. Among the 26 athletes with back pain only 13 had positive findings at MRI, while among the 19 asymptomatic athletes 7 showed lesions detectable with MRI. As for age, we observed that the younger athletes (17-19 years) had positive MRI findings in 38.5% of cases, while the players in the age group ranging from 23 to 26 years, had positive MRI findings in 56.2% of cases. The analysis of the different types of training of the volley-ball players and the control group, showed that 19 volley-ball players who followed appropriate training procedures had positive MRI findings in 21.1% of cases (in the control group the percentage was 20%). Among the 26 athletes who were trained with exercises that caused significant functional overload, 16 had intervertebral disk lesions at MRI (61.5%). Moreover, our data showed that the correlation of the incidence of disk lesions with the type of training (and relative varying degree of overload) is definitely more important than the one existing with the age of volley-ball players and the overall period of their athletic activity. MRI proved to be a useful technique for the early assessment of the intervertebral disk damage caused by an incorrect training in young athletes, even when asymptomatic.

Adolescent↗

PubMed1990

Sacrococcygeal chordoma: clinicoradiological study.

A case of sacrococcygeal chordoma is presented. We review the literature and we discuss the problems related to the etiology, the symptoms, the diagnosis and the treatment of this rare neoplasm. We present and discuss here the importance and the different possibilities of new diagnostic techniques, such as the CT and the MRI in the diagnosis and management of sacrococcygeal chordoma.

Chordoma↗

PubMed1990

Fast multiphase MR imaging of aqueductal CSF flow: 1. Study of healthy subjects.

Gradient-echo MR sequences are more sensitive to flow phenomena than spin-echo sequences are. We investigated aqueductal CSF flow by fast multiphase imaging. Fast multiphase imaging offers the opportunity to perform a dynamic study of fluid motion that is synchronous with the cardiac cycle. A section perpendicular to the cerebral aqueduct was imaged in 18 healthy volunteers. Serial, gated (every 50 msec from the ECG R wave), flow-compensated modulus images with 70 degrees-flip-angle excitation pulses were obtained with a single acquisition. The behavior vs time of CSF signal in the aqueduct was compared with that in the lateral ventricles. The former showed a peak at 0.47 +/- 0.1 fractions of a heart cycle after the R wave. No periodicity with the heart rate was observed for the ventricular CSF signal intensity. The mean CSF signal intensity in the aqueduct was found to range from about twice to three times that in the lateral ventricles over a cardiac cycle. Fast multiphase imaging is a sensitive and practical sequence for the MR investigation of aqueductal CSF flow. Its potential in patients with hydrocephalus is studied in a companion article.

Adult↗

PubMed1990

Fast multiphase MR imaging of aqueductal CSF flow: 2. Study in patients with hydrocephalus.

The signal intensity in the region corresponding to the cerebral aqueduct was evaluated in three patients with noncommunicating tension hydrocephalus (caused by aqueductal obstruction in two and type I Arnold-Chiari malformation in the other), seven patients with suspected normal-pressure hydrocephalus (three of whom subsequently underwent successful shunting), and 10 patients with ex vacuo (atrophic) hydrocephalus. A gradient-echo MR sequence, called fast multiphase imaging, was used. Serial images corresponding to different phases of the cardiac cycle were acquired. No flow-related enhancement was observed over the entire cardiac cycle in the patients with noncommunicating hydrocephalus. Patients with normal-pressure hydrocephalus showed a higher aqueductal CSF signal intensity, consistent with increased systolic flow rates, than patients with ex vacuo hydrocephalus. When comparing the above two groups of patients with a control group of healthy volunteers, significantly higher and lower values of the (mean) maximum aqueductal signal intensity were found in the normal-pressure hydrocephalus patients and the ex vacuo hydrocephalus patients, respectively. Fast multiphase MR evaluation of aqueductal CSF flow may help to differentiate patients with different types of hydrocephalus.

Adult↗