Biomedical subjects
Publications and source records attributed to B Demas.
A 57-year-old male with a high grade leiomyosarcoma of the prostate is presented. The local extent of the tumor was accurately described by magnetic resonance imaging (MRI). Following chemotherapy, the tumor volume was reduced by 60% and was judged to be clinically resectable by MRI. Despite radical cystoprostatectomy, the patient died of metastatic disease.
MR imaging (0.35 and 1.50 T) was used to assess the appearance of the seminal vesicles. The size and signal intensity of normal seminal vesicles vary with the age of the subject. In general, on T2-weighted images, the signal intensity of normal seminal vesicles is lower than that of fat in prepubertal children, similar to or higher than that of fat in adults, and similar to or lower than that of fat in patients older than 70 years of age. Endocrine and radiation therapy will influence the size and signal intensity of the seminal vesicles. The purpose of the essay is to illustrate the spectrum of seminal vesicle disease, including congenital anomalies, inflammation, and neoplastic disease. Although MR imaging is helpful in depicting seminal vesicle abnormalities, it does not allow differentiation of benign from malignant disease, distinction of hemorrhage due to tumor invasion from postbiopsy changes, or distinguishing between glandular obstruction due to tumor infiltration and mechanical compression.
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Forty computed tomography (CT)-assisted aspirations performed with only hand guidance were prospectively compared with 40 performed with a CT body-stereotaxic system. Although there was no statistically significant difference in lesion size and path length between the two groups, use of stereotaxis compared with hand guidance decreased by 75% the number of needle manipulations required to place a needle within a lesion. With the stereotaxic method, only 43 needle manipulations were required to confirm a needle placement in 40 lesions, with no lesion requiring more than two attempts. Use of stereotaxis decreased the number of localization scans by 80% and biopsy time by 50%. It is concluded that CT-guided needle placements with hand guidance are often inaccurate and, unless the lesion is large, require multiple needle manipulations to place a needle within the lesion. Stereotaxis-guided biopsies, on the other hand, decrease radiation exposure, biopsy time, and trauma from multiple needle punctures.