Comparative in vivo and pathological analysis of the blood-brain barrier in mouse telencephalic transplants.

The post-transplantation status of the blood-brain barrier (BBB) is still a matter of debate. In an attempt to define BBB properties after neural transplantation in mice of a defined genetic background, we have used two exogenous markers (horseradish peroxidase and Evans blue), one endogenous marker (immunoglobulins), and in vivo contrast enhanced magnetic resonance imaging (MRI) and compared the results obtained with the different methods. With all four techniques employed, we found the BBB to be reconstituted in 67% of the grafts 3 weeks after grafting, and in more than 90% of all grafts 50 days after grafting. Horseradish peroxidase and contrast enhanced MRI were the most sensitive techniques, the latter offering the unique advantage of repetitive scanning of individual grafts. Our findings provide important information for transplantation studies in mouse models for neurodegenerative diseases.

Optimization of prostate carcinoma staging: comparison of imaging and clinical methods.

PURPOSE: The diagnostic value of endorectal coil MRI, body coil MRI, transrectal ultrasound, digital rectal examination and PSA levels were prospectively analysed in order to define the most accurate preoperative staging method. METHODS: 33 patients with prostate carcinoma, who underwent subsequent prostatectomy, were enrolled in the study and examined on a 1.5T system using the body coil as well as the endorectal surface coil before and after the administration of contrast material. The results were compared to digital rectal examination, prostate specific antigen levels and endorectal ultrasound. RESULTS: Staging accuracy of endorectal coil MRI was 87.9% with a sensitivity of 88.9% and specificity of 86.7%. For body coil MRI, the staging accuracy was 75.7%, the sensitivity 66.7% and the specificity 87.9%, for transrectal ultrasound 69.6%, 41.7% and 100% and for the digital rectal examination 56.6%, 33.3% and 100%, respectively. Prediction was improved by combining results of endorectal coil MRI with PSA values. CONCLUSION: Endorectal ultrasound and digital rectal examination both had a tendency to underestimate the extent of the lesion. Endorectal coil MRI proved to be the best preoperative staging method. In combination with PSA values, diagnostic accuracy could be further improved. Therefore, local staging of prostate cancer could be based on these two parameters alone.

Contrast-enhanced endorectal coil MRI in local staging of prostate carcinoma.

OBJECTIVE: Our goal was to evaluate contrast-enhanced MRI using an endorectal coil in detecting and staging prostate carcinoma. MATERIALS AND METHODS: Sixty patients with clinically suspected prostate carcinoma were examined by T1-weighted contrast-enhanced endorectal coil MRI at 1.5 T. Results were compared with T2-weighted images in all cases and with histologic findings following radical prostatectomy in 28 patients. RESULTS: Prostate carcinomas showed no consistent pattern of contrast enhancement. In 27 patients, the tumor enhanced less than the surrounding prostatic tissue; in 10 patients, enhancement was heterogeneous; and in 23 cases, the lesion was hyperintense compared with normal glandular tissue. With respect to tumor delineation, contrast-enhanced sequences were superior to T2-weighted images in 1 case only; in 24 patients, the tumor could not be delineated at all. However, contrast-enhanced sequences provided a higher diagnostic confidence in delineating the seminal vesicles, prostate capsule, and neurovascular bundle in nine, six, and three cases, respectively. In the operated patients, accuracy, sensitivity, and specificity for staging advanced disease were comparable for both sequences. CONCLUSION: The T2-weighted sequences remain mandatory for delineation of prostate carcinoma. Contrast-enhanced T1-weighted sequences do not improve overall staging accuracy and therefore are not warranted routinely, but should be considered in cases requiring clearer delineation of the prostate capsule and/or seminal vesicles.

[High-resolution magnetic resonance tomography of the lesser pelvis using an endorectal coil]. / Hochauflösende Magnetresonanztomographie des kleinen Beckens mittels Endorektalspule.

Spatial resolution of MRI within the true pelvis can be increased by a factor of 12 using an endorectal coil. The value of this new method for demonstrating the prostate, the rectum, the cervix and vagina and of pathological processes of these organs was examined in 89 patients and the results compared with conventional body coil MRI. In 25 patients who underwent radical surgery the results of the preoperative studies were compared with the histological findings. Detailed recognition of anatomical structures was markedly improved by using the endorectal coil. Diagnosis of carcinoma of the prostate and extension of the tumour was accurately assessed in 33 patients. Preoperative staging was correct in 87%, compared with 73% when using a body coil. The difference was less marked in examinations for carcinomas of the rectum, the cervix and vagina. Nevertheless, staging was more accurate in a few cases with a better recognition of recurrences. MRI with endorectal coils will have an important role in diagnosis of carcinomas of the prostate in the future. Its use in the diagnosis of carcinomas of the rectum and cervix must be subject to further studies.