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Biomedical subjects

M Mascalchi

Publications and source records attributed to M Mascalchi.

At least 73 records · Page 4Linked to original sources
PubMed1995

MR angiography of spinal vascular malformations.

PURPOSE: To determine the potential and limitations of MR angiography in the evaluation of spinal vascular malformations. METHODS: Eleven consecutive patients with spinal vascular malformations proved with spinal selective arteriography underwent two-dimensional phase-contrast MR angiography. RESULTS: Abnormal vessels within the spinal canal were identified with MR angiography in 10 patients. In 1 patient with a dural arteriovenous fistula no definite vascular abnormality was seen with MR angiography. Correlation of MR angiography with spinal selective arteriography showed that the former allowed identification of the arterial feeder in 3 patients with intramedullary arteriovenous malformations and 2 with perimedullary arteriovenous fistula, whereas the source of intradural draining vein was seen in only 2 of 6 patients with dural arteriovenous fistula. CONCLUSION: MR angiography is a promising complementary tool to MR imaging for detection and characterization of spinal vascular malformations.

Adolescent↗
PubMed1994

MRI of pleomorphic xanthoastrocytoma: case report.

MRI showed a cortically-based partially cystic and markedly enhancing mass in the uncus of the right temporal lobe in a patient with long standing refractory partial complex seizures. Histopathological examination revealed a pleomorphic xanthoastrocytoma, a rare, usually benign tumour thought to originate from subpial astrocytes.

Adult↗
PubMed1994

Friedreich's ataxia: MR findings involving the cervical portion of the spinal cord.

OBJECTIVE: Loss of myelinated fibers and gliosis in the posterior and lateral columns of the spinal cord are histopathologic hallmarks of Friedreich's ataxia. These are accompanied by atrophy of the upper portion of the spinal cord. We performed a study to determine if MR imaging can be used to detect signal changes in the white matter tracts of the cervical spinal cord in these patients. SUBJECTS AND METHODS: The cervical spinal cord was imaged with a 0.5-T MR imaging system in 10 patients with Friedreich's ataxia and in 14 patients with cerebellar ataxias, who served as control subjects. In all of them, the examination protocol included sagittal T1-weighted spin-echo images, sagittal short T1 inversion-recovery images, and axial cardiac-gated long TR spin-echo or ungated low-flip-angle (20 degrees) gradient-recalled-echo images from C2 to C6. The anteroposterior diameter of the spinal cord at the level of C3 on axial images was measured on the display console in patients and control subjects. Two observers who did not know the clinical diagnosis were then asked to evaluate hard copies of the entire image set for each subject for possible intramedullary signal abnormalities. RESULTS: The anteroposterior diameter of the spinal cord was decreased in all but one of the patients with Friedreich's ataxia. Abnormal signal in the posterior or lateral columns of the spinal cord was observed on sagittal and axial images in nine patients with Friedreich's ataxia and in none of the control subjects. CONCLUSION: MR images of the cervical spinal cord in patients with Friedreich's ataxia show thinning and intramedullary signal changes in the cervical portion of the spinal cord, consistent with degeneration of posterior and lateral white matter tracts. These MR findings might be helpful for differential diagnosis in patients with progressive ataxia of uncertain clinical type.

Adult↗
PubMed1994

[Gadolinium-DTPA combined with a fat suppression technique in studies with magnetic resonance at 0.5 T in soft-tissue neoplasms].

Combination of fat suppression techniques with intravenous paramagnetic contrast administration is usually performed using high-field MR systems. We combined a modified three-point Dixon technique for fat suppression with gadolinium-DTPA administration in the investigation of soft tissue neoplasms at 0.5 T. Nineteen patients with 21 neoplasms (14 primary malignant, 2 metastatic, 5 benign tumors) were examined. Examination protocol included unenhanced SE T1, PD and T2-weighted images. After the intravenous administration of gadolinium-DTPA (0.1 mmol/kg), a modified three-point Dixon technique provided three image sets, i.e., conventional T1-weighted SE images, fat-suppressed T1-weighted images and water-suppressed T1-weighted images. Two observers evaluated the lesions for conspicuity and size in three image groups: unenhanced T1-, PD and T2-weighted images, enhanced conventional T1-weighted images, enhanced T1-weighted images with fat suppression. Ten lesions showed greater conspicuity on enhanced fat-suppressed images than on unenhanced T1-, PD and T2- and enhanced conventional T1-weighted images. In 16 cases lesions were more conspicuous on enhanced water images than on conventional enhanced T1 images. Ten tumors exhibited a larger size (difference exceeding 20%) on enhanced fat-suppressed images. The combination of gadolinium with the modified Dixon technique improves the demonstration of soft tissue neoplasms at 0.5 T and allows lesion size to be measured more accurately.

Adipose Tissue↗
PubMed1994

[Magnetic resonance angiography at 0.5 Tesla of the renal arteries. Capabilities and limitations of the 2-dimensional phase contrast technique].

To investigate the potentials and limitations of Magnetic Resonance Angiography (MRA) of the renal arteries at mid-field strength, 16 patients with arterial hypertension of suspected renovascular origin were submitted to MRA at 0.5 T with the two-dimensional (2D) phase-contrast technique and to arteriography. MRA yielded diagnostic images in 15 (94%) patients in whom MRA and arteriography identified 38 and 39 renal arteries, respectively. MRA sensitivity and specificity to steno-occlusive alterations of the renal arteries demonstrated by arteriography were 83% and 96%, respectively. These results, although obtained in a small group of patients, indicate that MRA of the renal arteries with a mid-field MR system and the 2D phase-contrast technique can allow the diagnosis of steno-occlusive alterations of the renal arteries. Main MRA limitations were its long acquisition time and some variability in the quality of the MRA images. Nevertheless, the ongoing rapid technical developments in the hardware of MR systems leave room for improving the accuracy of mid-field MRA of the renal arteries and justifies optimism as to its role in the screening of renovascular hypertension.

Adult↗
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

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

Slowly progressive familial dementia with recurrent strokes and white matter hypodensities on CT scan.

We describe 2 normotensive sisters presenting slowly progressive dementia associated with acute or subacute focal neurological symptoms, unilateral or bilateral motor signs, and dysarthria. Their father, who died in the seventh decade, had a similar clinical picture. Computerized axial tomography (CT) scan of the head showed symmetrical hypodensities in the periventricular white matter and mild to moderate hydrocephalus. In these patients a diagnosis of Binswanger's disease was based on the clinical features supported by white matter changes on CT scan. Our study suggests that genetic factors may play a role in the etiology of Binswanger's disease.

Adult↗
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

Spinal intramedullary subependymomas: case report and review of the literature.

A cervical spinal intramedullary subependymoma in a 53-year-old man is reported, and the relevant literature is reviewed. Spinal cord subependymomas seem to follow a benign course. Radiotherapy should not be administered to these patients. Magnetic resonance imaging, even with enhancement, is not able to distinguish between a subependymoma and the more common ependymoma.

Ependymoma↗
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↗