Intérêt d’une semi-quantification et d’une analyse statistique automatique pour l’interprétation de la tomoscintigraphie cérébrale de perfusion dans la maladie d’Alzheimer

IntroductionAs the visual interpretation of the brain perfusion SPECT for the diagnosis of Alzheimer's disease might be difficult, it is wished to benefit from techniques allowing to improve the diagnostic accuracy especially for the inexperienced readers.Materials and methodsThree readers retrospectively interpreted 77 ^99mTc-ECD SPECT studies within the context of suspected neurodegenerative disease. The probability of Alzheimer's disease was quoted from 1 to 5, and the optimum sensitivity and specificity values were determined from ROC curves. The readers also attributed a hypoperfusion score to 13 brain regions; a diagnosis was obtained from this semi-quantification using a simple logic rule. The SPECT scans were also analyzed using the Planet Neuro software and a diagnosis was reached from a threshold for 2 of the 90 analyzed regions. The gold standard was established by a comprehensive neurological evaluation with at least 5 years of follow-up.ResultsThe sensitivities and specificities of the three readers were 50 %, 56 %, 28 % and 76 %, 83 % and 90 %, respectively. Using the semi-quantification they were 50 %, 67 %, 61 % and 54 %, 85 %, 69 %. The results of two readers were more in agreement. Using the automatic quantification, sensitivity was 78 % and specificity 81 %.ConclusionThe semi-quantification seems to ameliorate the results of and the agreement between certain readers. However, the automatic quantification seems to be the only way of assisting all of the readers to improve their diagnostic performances.     

Matériel pour la récolte du microplancton dans les mares et étangs

Sans résuméCollège de France et Centre de Recherches Hydrobiologiques du C.N.R.S. à Gif.     

Effets de la fluorescence résiduelle dans les tissus biologiques sur les signaux de fluorescence résolus temporellement par la méthode des éléments finis

A computational model based on finite element method is derived to examine how the simulated time-dependent signals are related to the presence of residual fluorescence in biological media surrounding a fluorescent object. We apply a subtraction technique on recorded data when imperfect uptake of fluorescing agent into the tumor is considered. We show the limits of the subtracting method for low target: background fluorescent absorption contrast by extracting the time to reach the half maximum and analyzing the maximum of the time-resolved signals versus target depth.     

Une nouvelle observation d’une métastase testiculaire d’un adénocarcinome prostatique: Aspects diagnostiques et éthiopathogéniques

Testicular metastases from prostatic adenocarcinoma are rare. They are often asymptomatic and diagnosed incidentally or at autopsy after orchidectomy in more advanced stages of the disease. The authors report a new case and review the diagnosis and aetiopathogenesis of these metastases. A 67-year-old patient with prostatic adenocarcinoma presented with painless right testicular mass for two months with no inflammatory signs. Germ cell tumour serum markers were negative. Scrotal ultrasound showed a large testicular tumour measuring 7×4×3cm. Histological examination revealed a solid non-differentiated tumour, not suggestive of primary testicular tumour. The immunohistochemical panel confirmed the prostate as the primary site due to the positivity of cytokeratins, PSA and PSAP and the negativity of classical markers of germ cell tumours. Testicular metastases from prostatic adenocarcinoma are rare, but their incidence is currently on the increase. They are often asymptomatic and discovered after pulpectomy. This diagnosis must be considered in the case of a testicular mass in patients over the age of 50 with a history of prostatic adenocarcinoma. The diagnosis was established after orchidectomy by histological examination and immunohistochemical tests.     

Méthodes d’évaluation des érections automatiques nocturnes dans les dysfonctions érectiles

For more than 25 years, the study of nocturnal penile tumescence (NPT) has been a basic element in the investigation of erectile dysfunction. Numerous methods have been proposed; always non-invasive, generally not very onerous and easily achieved. They require little more than a basic understanding of physiology, and knowledge of the qualitative and quantitative criteria for assessing NPT, in order to avoid any incorrect or dangerous interpretation. Based on more than 8000 nights of recordings, it is possible to separate the advantages, inconveniences and operating costs of the major instrumentation options. Although rather unsatisfactory, plethysmography and rigidometry of NPT have become the cornerstone for investigating erectile dysfunction. Always necessary, sometimes these examinations alone are sufficient, for example when they are normal and allow confirmation of a psychogenic aetiology of impotence. In other situations they must be supplemented with other complementary examinations, in which case the results show an 80% correlation with NPT. A revival of interest in the study of NPT will occur once we have achieved the impossible: the availability of a cheap instrument allowing recording of turgidity, rigidity and REM sleep, without discomfort and in the patient’s home.     

Intérêt de la TEP dans le bilan d’extension et l’évaluation de la maladie résiduelle des séminomes testiculaires : étude rétrospective

AimsTo evaluate the value of PET/CT comparatively to CT in staging and restaging after chemotherapy of testicular seminoma, to assess quantitative methods and prognostic value of PET in post-chemotherapy residual masses.MethodsThirty-two patients and a maximum of 65 targeted lesions visualized on PET-CT and CT performed for staging and therapeutic response assessment were analysed and compared. Each lesion was quantified according to miscellaneous SUV normalized methods. Optimal threshold of SUV for prediction of residual disease was obtained (ROC method). The prognostic value of PET/CT at the completion of treatment was determined with progression free survival study (Kaplan-Meier method).ResultsPET/CT exhibited higher accuracy than CT in the initial staging and assessment of therapeutic response, respectively 98% versus 83.3% and 95.1% versus 75.6%. Quantification, whichever method, was not more efficient than visual reading for prediction of residual disease. Progression-free survival was higher with negative than with positive PET/CT (P = 0.0033).ConclusionOur work demonstrates that PET/CT exhibits better accuracy than CT in both staging and restaging at the end of treatment. Quantification methods do not improve accuracy of PET/CT for prediction of viable residual disease. The prognostic value of PET/CT appears very promising and needs to be confirmed by large prospective studies. PET/CT appears to be a relevant method of prognostic stratification of the risk of relapse in seminoma.     

Indications d’une étude méiotique dans l’infertilité masculine

Meiotic investigation is rare in male infertility. Now, some mutations affecting spermatogenesis exhibit characteristic cytogenetic figures, whereas testicular histology does not show specific aspects of this pathology. In male infertility with abnormal somatic caryotype, the aim of meiotic survey is to find the mechanisms inducing spermatogenic failure, and thus to lead to a better understanding of normal spermatogenesis. In addition to cytogenetic techniques, meiosis is also investigated by electron microscopy and molecular biology. Also, we think that a larger place must be grant to meiotic study in male infertility evaluation when the indication of testicular histopathology was settled.