Biomedical subjects
Publications and source records attributed to L Landoni.
Serial angioscintigraphy with 99mTc-pertecnetate and gamma camera was carried out in more than 500 cases of cerebropathies with various but prevalently vascular pathogenesis. Pictures are described and discussed with reference to the differential diagnosis, and a number of significant cases are reported in detail.
The calcifications of Fahr disease that are detected by CT in the dentate nuclei of the cerebellum, basal ganglia, and white matter of the cerebral hemispheres displayed three patterns with magnetic resonance imaging using the multiple echo technique: (a) cerebellar calcifications were undetected; (b) basal ganglia calcifications displayed low or no signal and appeared as "black" areas in four echoes; and (c) white matter calcifications displayed a high signal in the four echoes and appeared intensely white. The different behavior of the three calcified sites probably reflects different stages of the disease or different metabolic states with predominance of inert calcium deposits in the basal ganglia. In the white matter there is probably a higher concentration of binding proteins and mucopolysaccharides.
Magnetic resonance imaging was performed in eight patients with extramedullary cervical tumors; two were studied with a 0.15 T resistive system and six with a 0.5 superconductive unit. All tumors were verified surgically: Five meningiomas and three schwannomas were found. Magnetic resonance demonstrated the location and size of the tumors as well as their relationship with and mass effect on the adjacent spinal cord. Meningiomas showed a tendency to have relaxation times close to those of the normal parenchyma; in multiple echo sequences their signal tends to decay in a way similar to that of the spinal cord. The different signal from the surrounding cerebrospinal fluid sometimes provides a visual cleavage to define the extramedullary location of the neoplasm. Schwannomas and neurofibromas have a less constant behavior; their T2 relaxation time may be slightly longer than that of the spinal cord and the tumor may display a more intense signal in the T2 weighted images. Usually, however, the signal intensity of the extramedullary tumors is lower than that of the intramedullary.
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More than 1300 patients have been examined with MR for diseases of the CNS since October 1983. Eight hundred patients were studied with a resistive 0.15 Tesla system and the remaining with a superconductive 0.5 Tesla system. Lesions of the cervical spinal cord, syringomyelia and intra or extra-axial tumors, were perfectly demonstrated. The absence of artefacts in the posterior fossa, as well as sagittal and coronal slices, allow an excellent demonstration of lesions, particularly of brain stem tumors. In a large group of patients with multiple sclerosis, MR has proven to be diagnostically superior to CT, evoked potentials and CSF examination. Sensitivity is very high but specificity may be low in infra- and supratentorial gliomas. Differentiation of tumor from oedema may be difficult.