The effects of three physiologically different vasomodulators, angiotensin II (a vasoconstrictor), hydralazine (a vasodilator), and histamine (a permeability modulator), on the pharmaco-kinetics of entry of small molecules (measured by Gd-DTPA concentration) into normal and abnormal tissue were studied in rats implanted with R3230 AC tumors. Sequential dynamic Gd-DTPA-enhanced MRI studies, one before and one after vasomodulator administration, were performed, and the signal intensities of various tissues analyzed. Angiotensin II (6 micrograms/kg) reduced blood flow in tumors, but increased it in muscles. Hydralazine (5 mg/kg) reduced blood flow in tumors, kidneys, and livers, and slowed Gd-DTPA clearance from tumors, livers, and muscles. Histamine (25 micrograms/kg) increased renal blood flow, hastening Gd-DTPA clearance causing reduced measurable blood flow in tumors and muscles. By simultaneously monitoring the effects in various tissues, the pharmacokinetic effect of each drug in the entire body could be obtained.

An 18‐week‐old boy was referred by the pediatric service for evaluation of a large congenital nevus. The baby was a term infant who was noted to have extensive pigmented skin lesions at birth that extended from the scalp to the feet. Apgar scores and physical examination (including neuromuscular examination) were within normal limits. Electroencephalographic tracings were normal and unenhanced cranial computerized tomography (CT) was reported as showing a subarachnoid cyst with atrophic changes, involving predominantly the inferior aspect of the cerebellar hemispheres bilaterally. Hydrocephalus or signs thereof were not present. Lumbar spine films were normal. The patient was next evaluated at age 3 months, where he was reported to roll over, reach for objects, and smile. At age 17 weeks, the baby had dermabrasion of an abdominal portion of his congenital nevus, followed by autologous epidermal cell autograft. The baby was subsequently hospitalized at the University of California Irvine Medical Center for complications from this procedure. Upon initial dermatologic evaluation, the baby was noted to have uniformly brown pigmented bathing‐trunk verrucous lesions covering his buttocks, scrotum, two‐thirds of his trunk, and proximal portions of his extremities. Multiple similar but smaller lesions were noted on the face, scalp, and distal extremities (Fig. 1). Tense anterior fontanelles, frontal bossing, Babinski reflexes bilaterally, and possible “setting‐sun” sign (downward gaze of the eyes secondary to pressure from the midbrain) were apparent. Although the length (size) percentile for the baby was normal, the plot of head circumference was noted to deviate above the normal range by age 3 months. Magnetic resonance imaging (MRI) of the brain was performed. The midline sagittal T1 weighted image (Fig. 2a) demonstrated an enlarged posterior fossa with vermin hypoplasia and hydrocephalus. An axial image through the dilated sylvian aqueduct revealed a hyperintense focus, characteristic of melanocytes, adjacent to the dilated left temporal horn (Fig. 2b). More superiorly, enhancing leptomeningeal deposits were identified (not shown). Cerebrospinal fluid was obtained after subsequent placement of a right ventricular‐peritoneal shunt. The fluid was bloody, but sterile, and without malignant cells. Staining for melanin of the few nucleated cells in this limited cerebrospinal fluid sample was negative. Several excisional biopsies of a nevus from locations on the feet, wrist, back, and buttock showed the picture of either congenital melanocytic nevus or congenital melanocytic nevus with atypical melanocytic hyperplasia; however, no significant atypia was identified in the specimens containing foci of atypical melanocytic hyperplasia.

We attempted to demonstrate the morphological changes of an extrauterine pregnancy by nuclear magnetic resonance imaging. Spin echo mode was used to take images in all three space directions. An enlargement of the uterus with an empty cavity and a hyperplasia of the supporting vasculature were demonstrated as alterations correlating with an extrauterine pregnancy.

No abstract

Patients with a corpus carcinoma were examined by magnetic resonance imaging before and after application of the paramagnetic contrast agent Gd-DTPA. The images were obtained by spin echo technique with the repetition times 0.5 s or 1.8 s and the echo times 35/70 ms. The dosis of the contrast agent was 0.1 mmol per kg body weight. The contrast between myometrium and tumour increased after injection of the contrast agent and structures within the tumour can be better differentiated. The pelvic organs (bowel and urinary bladder) can be seen in greater detail. Images taken with short repetition times after application of Gd-DTPA show greater contrast than pictures picked up with the same imaging parameters without contrast agent. Furthermore, there is an improvement compared with images taken with long repetition times.