Cerebral MR Perfusion Imaging Analysis of Peritumoral Tissue.

Highly malignant gliomas have an infiltrating growth making it impossible to establish the exact limits of the lesion with magnetic resonance images after contrast medium administration because the peripheral component of the lesion does not enhance. On the contrary, cerebral metastases have an expansive growth and therefore lack a peripheral component beyond the enhanced area. In some cases the MR perfusional technique can demonstrate neoplastic tissue even with little damage to the brain-blood barrier and therefore with no enhancement.

Perfusion MRI in the evaluation of the relationship between tumour growth, necrosis and angiogenesis in glioblastomas and grade 1 meningiomas.

Angiogenesis is a common characteristic of tumours, and it is reasonable to assume that it has an influence on tumour growth, depending on the grade of malignancy. We therefore studied angiogenesis in 25 patients: 14 with glioblastoma multiforme and 11 with grade I meningioma. Our aim was to assess how angiogenesis conditions growth and necrosis.

Study on the variations of the apparent diffusion coefficient in areas of solid tumor in high grade gliomas.

Present knowledge suggests that in glioblastoma multiforme the value of the apparent diffusion coefficient (ADC) is elevated in the solid part and hyperintense in T1, in spite of the elevated cellularity, and also in areas where peritumoral vasogenic edema is present. The purpose of our study has been to verify in vivo if the ADC increases in areas of solid tumor because of an increased presence of edema, like it happens in areas surrounding the tumor. Sixteen patients with histologically verified glioblastoma multiforme underwent a magnetic resonance (MR) examination with sequences: T1-weighted pre and post contrast, diffusion-weighted at b = 0 and b = 1000 s/mm(2), perfusion-weighted.

Seroprevalence of hepatitis A virus and Helicobacter pylori infections in the general population of a developed European country (the San Marino study): evidence for similar pattern of spread.

Objective: To evaluate the role of faecal-oral transmission in the spread of Helicobacter pylori.

Design: A cross-sectional comparison of the patterns of hepatitis A and H. pylori seropositivity.

Population-based survey of hepatitis A virus infection in the Republic of San Marino.

In 1990-1991, the prevalence of antibodies to hepatitis A virus infection (anti-HAV) was assayed by the ELISA method among 1528 apparently healthy subjects, 20-85 years old in the Republic of San Marino. Subjects were selected from the list of residents by a random stratified sampling procedure with a proportional allocation by age, sex and district of residence. The overall anti-HAV prevalence was 64.