Contrast-enhanced CT rim sign may predict vestibular schwannoma adhesion and postoperative complications

AIM

To investigate the clinical and radiological features to predict adhesion between vestibular schwannoma (VS) and brain tissue which is a critical risk factor for postoperative infarction and residual tumour.

MATERIAL AND METHODS

One hundred and seven consecutive VS surgeries were analysed. After excluding cases without contrast-enhanced (CE) computed tomography (CT), Koos grades 1 and 2, and cases with incomplete clinical data, 44 patients were finally included in the study. Enhancement of the tumour capsule on the brainstem side on CE-CT was defined as the CE-CT rim sign, which was analysed along with clinical characteristics, including tumour adhesion and postoperative complications.

RESULTS

Eight patients exhibited CE-CT rim signs; 17 had tumour adhesions. Four patients had postoperative infarction at the ipsilateral middle cerebellar peduncle; 18 exhibited postoperative infarction and/or residual tumour at the middle cerebellar peduncle. The CE-CT rim sign significantly correlated with tumour adhesion, postoperative infarction, and postoperative infarction and/or residual tumour in the cerebellar peduncle. Univariate regression analysis revealed that the CE-CT rim sign significantly correlated with tumour adhesion (odds ratio [OR] 6.81, 95% confidence interval [CI] 1.18-39.25, p=0.032) and postoperative infarction and/or residual tumour at the cerebellar peduncle (OR 6.00, 95% CI 1.04-34.31, p=0.044).

CONCLUSION

The CE-CT rim sign was identified in 18.2% of patients with VS and significantly correlated with tumour adhesion and postoperative complications, such as postoperative infarction and residual tumour. This study highlights the importance of the preoperative CE-CT rim sign in VS, which is predictive of tumour adhesion and postoperative complications.

Health-life expectancy according to various functional levels

OBJECTIVES

To estimate disability-free life expectancy according to three functional levels.

DESIGN

A 2-year prospective study of older residents in a rural Japanese community. The functional ability of each individual was determined with self-completed questionnaires at baseline (1994) and at follow-up (1996).

SETTING AND PARTICIPANTS

All residents of Wakuya Town, Japan, who were aged 65 years or older at the start of the study in 1994 (n = 3590).

MEASUREMENTS

Single-year increment-decrement life tables were constructed from mortality rates and incidence of disability rates. Independent life expectancies in three functional areas: basic activities of daily living (ADL), instrumental activities of daily living (IADL), and mobility, were estimated for each sex and each year of age.

RESULTS

The incidence and prevalence of disability were similar in men and women. For both sexes, independent life in IADL was shorter than independent life in ADL and mobility. The development and progression of disability were different between sexes: men experienced disability at a younger age and at a faster rate than women.

CONCLUSIONS

The slow progress of disability, with a longer duration in a disabled state among women, induces a heavy burden on health and welfare resources. Interventions to delay the onset of disability in women should reduce the economic burden to society as well as improve the quality of life. Prospective studies to look at the process of disablement, based on direct observation, are needed to confirm the gender differences.

Selective induction of glandular stomach carcinoma in F344 rats by N-methyl-N-nitrosourea

To study the carcinogenic action of N-methyl-N-nitrosourea (MNU) on the stomach, MNU in distilled water at a concentration of 400 ppm was provided as drinking water to F344 male rats for 25 weeks (group I) or 15 weeks (group II). Twenty weeks following the cessation of the administration, invasive adenocarcinomas were found in the glandular stomach in 100% of 16 rats in group I and 38% of 21 rats in group II. Bone formation occurred within the stroma of carcinoma in 5 rats in group I. No neoplastic lesions developed in the esophagus, forestomach or duodenum of any rat. Thus, MNU in drinking water selectively induces glandular stomach carcinoma in high incidence in these rats.

[Histopathologic study of rapidly induced colonic carcinoma in rats by N-methyl-N-nitrosourea--with special reference to histogenesis]

The rat model of N-methyl-N-nitrosourea (MNU)-induced colorectal carcinogenesis was studied to determine histogenesis and evaluate early proliferative lesions and invasive carcinoma by the measurement of DNA content. Twenty-five male Fischer rats, weighing 150-160 g, were intra-rectally given MNU dissolved in distilled water, at a dose of 2 mg/rat, 3 times weekly for 5 weeks. Histopathologically, the lesions were classified into 3 foci, that is dysplastic focus composed of single gland, intra-mucosal dysplastic focus and macroscopic or invasive carcinoma. Macroscopic lesions were gradually increased in number and size with time. The earliest lesion, which could be recognized as single gland dysplastic foci, not only preceded the occurrence of invasive carcinoma, but also appeared most frequently in the colonic segment that subsequently showed the site of the highest incidence of advanced carcinoma. Thus, single gland foci might be precancerous lesions. However, on the basis of similar findings of the DNA distribution pattern in single gland foci, intramucosal foci and invasive carcinoma, these foci could be regarded as "de novo carcinoma" or, at least, it can be said that the development of carcinoma was not preceded by adenomatous polyp in our present experiment.