Pediatric rectal and perineal problems

[Rectal tonsil or lymphoid follicular hyperplasia of the rectum]

The rectal tonsil is a reactive proliferation of lymphoid tissue located in the rectum. The morphology of the lymphoid proliferation of the colon is usually polypoid or, less commonly, nodular. Only in exceptional cases does lymphoid proliferation of the colon present as a mass in the rectum (rectal tonsil), although this is the most common presentation in middle-aged patients. It is important to be familiar with the rectal tonsil because in cases of exuberant growth it can be difficult to distinguish it from other types of masses. We present the case of rectal tonsil in a four-year-old girl. We describe the magnetic resonance imaging findings and review the literature.

Magnetic resonance imaging anatomy of the female genitalia in premenopausal and postmenopausal women

PURPOSE

We used contrast enhanced magnetic resonance imaging (MRI) of the female genital organs to describe normal anatomy and differences between premenopausal and postmenopausal women.

MATERIALS AND METHODS

A total of 12 healthy premenopausal and 9 healthy postmenopausal women underwent MRI. A 1.5 Tesla system with phased array coils anterior and posterior to the pelvis was used to produce T1-weighted images before and after intravenous administration of MS-325 (Epix Medical, Cambridge, Massachusetts), a new gadolinium based blood pool contrast agent. Select structural dimensions were measured for reference.

RESULTS

The clitoris and vestibular bulbs were well delineated on T1-weighted post-contrast images. The clitoral unit formed a brightly enhancing, wishbone-shaped structure lying just anterior to the inverted V of the bulbs, which surrounded the urethra and vagina. The urethral complex had a target-like appearance with layers that were discernible on T1 post-contrast images. The urethra, vagina and rectum formed a distinct complex within uniformly enhancing soft tissue. The vagina was well visualized in premenopausal subjects but without distinguishable mucosal rugae or clearly separate layers in postmenopausal subjects. Postmenopausal subjects were also observed to have smaller labia minora width, vestibular bulb width, vaginal width and wall thickness, and cervical diameter. Pelvic and genital structures were not well visualized on T1 noncontrast images.

CONCLUSIONS

To our knowledge we describe detailed female genital anatomy for the first time using MRI with MS-325 contrast medium. The clitoris, vestibular bulbs, labia majora and minora, urethra, vagina, cervix and rectum are well visualized on T1 post-contrast images. The observed genital anatomy on MRI was consistent with descriptions in current anatomical texts. Differences in the female genitalia between premenopausal and postmenopausal women were discernible on MRI. These data are important for future studies using MRI for evaluating anatomical anomalies, postoperative changes and female sexual function.