Multiphasic MR imaging: a new method for direct imaging of pulsatile CSF flow

A new technique is described that allows for the creation of pure pulsatile flow magnetic resonance (MR) images in a single acquisition. Five to 16 electrocardiographically gated images spanning the entire cardiac cycle are obtained with use of a gradient-echo pulse sequence. The section can be varied from 4 mm thick to full thickness projection. Taken singly, each image provides direct assessment of flow direction and velocity. Subtraction of image pairs eliminates signal detected from stationary protons, producing images of pulsatile flow. In this study the technique was used to image the flow of cerebrospinal fluid (CSF) in healthy subjects and in one patient with syringohydromyelia. The data suggest that multiphasic MR imaging provides a powerful means for the noninvasive assessment of CSF pulsatile flow dynamics and may have potential clinical application for the investigation of a variety of abnormalities such as normal pressure hydrocephalus, syrinx, and spinal block.     

Type II estrogen binding sites (EBS) in intracranial tumors

Four meningiomas and six neuroepithelial tumors were assayed for the presence of estrogen receptors (ER), type II estrogen binding sites (EBS) and progesterone receptors (PgR). ER were detected in 7 out of 10 cases with levels ranging between 2.5 and 20.7 fmoles/mg of cytosolic protein. On the contrary, PgR were found in all samples (10 cases) and their levels ranged between 8.8 and 130.6 fmoles/mg of cytosolic protein. All tumor samples expressed appreciable amounts of type II EBS ranging between 452 and 2320 fmoles/mg of protein. Although the precise functional role of type II EBS is still unknown, their presence may reflect an hormonal sensitivity of these tumors.     

Maternal serum Down syndrome screening: unconjugated estriol is not useful

Study of 41 known Down syndrome cases and 441 matched controls did not confirm earlier reports that low unconjugated estriol levels can be used to detect fetal Down syndrome. Hence the obstetric community should exercise caution in using unconjugated estriol levels as a marker in prenatal Down syndrome screening.     

Rickettsia rickettsii infection of cultured human endothelial cells induces tissue factor expression

Microvascular thrombi underlie many of the clinical manifestations of Rocky Mountain spotted fever (RMSF), a disease characterized by Rickettsia rickettsii infection of vascular endothelial cells. Studies were designed to determine whether R rickettsii-infection of cultured human umbilical vein endothelial cells results in tissue factor (TF) induction, a process that could directly activate coagulation in infected vessels. Whereas uninfected endothelial cell cultures showed essentially undetectable TF mRNA and activity, both TF mRNA and activity were present after R rickettsii infection. TF mRNA levels were transient, peaking at 4 hours after the initiation of infection, whereas the peak of TF activity occurred at 8 hours. Induction of the TF response requires the intracellular presence of R rickettsii organisms, because uninfected rickettsia were ineffective and the response was blocked by inhibiting rickettsial entry using cytochalasin B. TF induction was not mediated by endothelial cell release of soluble factor, because no response was induced using culture medium conditioned by R rickettsii-infected cells. Furthermore, preadsorption of suspensions of R rickettsii with polymyxin B to remove contaminating lipopolysaccharide did not eliminate the TF response. Induction of TF in vital endothelial cells during R rickettsii infection could be the trigger for vascular thrombus formation of RMSF.     

MR gated subtraction angiography: evaluation of lower extremities

We report the first clinical experience with a new method for projective imaging of blood vessels (angiography) using magnetic resonance. Vascular contrast is produced noninvasively by the phase response of moving protons. Diastolic and systolic gated images produce, respectively, flow signal and flow void; the difference image is a map of the pulsatile flow: an arteriogram. Preliminary studies are presented of the lower extremities of one healthy volunteer and four patients (one each with occlusive disease, soft-tissue tumor, arteriovenous malformation, and venous femoral-popliteal graft). Patient data are compared with accompanying conventional arteriograms, and the new method is discussed.     

Morphometric analysis of the optic disc surface

Purpose: Since the glaucomatous loss of nerve fibers changes the appearance of the optic disc, we evaluated the morphology of the surface of the optic disc in normal and glaucomatous eyes by using a computerized system to provide the reciprocal position of a large number of points placed on its surface in order to study the clinical significance of differences in the smoothness of optic disc surface. Methods: The morphology of the optic disc surface was evaluated by means of simultaneous stereoscopic videographic pictures (IMAGEnet X Rev-3.51b — Topcon Europe, The Netherlands): the reciprocal distribution of a large number of points located on the surface of one eye of 100 subjects randomly chosen (45 normal and 55 glaucoma patients) was studied.In order to define the level of smoothness of the optic disc surface, the differences of the relative position of each surface point were studied by measuring the standard deviation (SD) from the average heights of the points (n. ranging from 623 to 1916 depending on the size of the disc area) that identify the optic disc surface. Results: The coefficient of variation of the reciprocal location of the points, placed on the optic disc surface at the different measurements performed by a single operator was 10.4%. The differences in Optic Disc Surface Smoothness (ODSS) between glaucoma and normal group were statistically significant (p < 0.0001 using Mann-Whitney U test). No correlation was detectable between age and standard deviation.The best threshold value, calculated using ROC methodology, able to separate the two groups was: normal group: SD <- – 17.79 (–1 × 10^–2 mm); glaucoma group: SD > – 17.79 (– 1 × 10^–2 mm).Such threshold value had a sensitivity of 82.1 %, a specificity of 92.2% and a diagnostic precision (DP) of 86.5% in dividing the glaucoma group from the normal group. Conclusion: ODSS is a global index of optic disc conditions based on quantitative measurements of the morphology of the optic disc surface. As such it does not provide information about the location and the characteristics of optic disc damage. Nevertheless, ODSS measurement is able to separate normal from glaucomatous optic disc with a rather interesting sensitivity, specificity and diagnostic precision (DP). As such it could be useful both for research and clinical applications.     

Indications for breast imaging in women under age 35 years

To determine appropriate indications for breast imaging in young women, the authors correlated patient histories with mammographic and/or sonographic findings and biopsy or follow-up results for 625 patients aged 13-34 years. The only important indications were a palpable mass and suspicion of an abscess. Of the 335 studies performed for evaluation of a palpable mass, 184 (55%) were normal, 28 (8%) were compatible with benign disease, and 123 (37%) were suggestive of malignancy. Biopsies were performed in 73 patients; the findings were benign in 67 cases, and carcinoma was found in six. Imaging studies were considered helpful in four of the 15 cases of suspected abscess, in that the studies established the presence and extent of an abscess. Studies in 275 women were performed for a variety of other indications. The findings were normal in 239 (87%) studies, benign in 21 (8%), and suggestive of malignancy in 15 (5%); there were no known carcinomas in any of the patients. Women with the "low-yield" indications identified in this study should be followed up clinically rather than referred for imaging studies.     

Irradiation induces release of von Willebrand protein from endothelial cells in culture

Human umbilical vein endothelial cells in tissue culture were irradiated with doses between 0 and 40 Gy, and the released von Willebrand (vW) protein and that which remained associated with the cells was quantitated. Doses of 20 Gy and higher produced a statistically significant increase in amount of vW protein secreted. This release was present whether the cells were labeled continuously throughout the experiment or just prelabeled before irradiation. An increase in fibronectin secretion was not observed. The release response to radiation was slow, reaching significance close to 24 hours after irradiation. The release of vW protein was not due to cell lysis, because the secreted vW protein contained very little of the large 260- kilodalton vW precursor subunit present in cell lysates and the cells appeared intact by immunofluorescence staining.