Diffusion-weighted MRI: detection of cerebral ischemia before and after carotid thromboendarterectomy

PURPOSE: Conventional postoperative evaluation of patients following carotid thromboendarterectomy (TEA) consists of a clinical neurologic examination to assess neurologic deficits, color duplex ultrasound to document the surgically reestablished patency of the carotid artery, and CT for exclusion of postoperative ischemic infarctions. Recent studies prove that diffusion-weighted MRI is more sensitive in the detection of fresh insults than conventional MRI and CT. The objective of the study was to ascertain the incidence of clinically asymptomatic peri-and postoperative ischemic infarctions visualized at MRI. METHOD: We included 52 patients in the study. Fifty-one patients (31 men, 20 women; average age 68 years) underwent cranial MR examination including a diffusion-weighted sequence at 24 h prior to carotid TEA and again 24 h following the procedure. One patient did not agree to participate. RESULTS: In 29 of 51 patients (56%), neither the pre-nor the postoperative MR scans showed any diffusion abnormalities. In 16 patients (31%), however, preoperative MRI detected fresh ischemic insults. In nine patients (17.6%), the size of the insult resulted in surgery being postponed for 4 weeks. In six patients (11.8%), postoperative MRI returned findings of fresh disturbances of diffusion suggestive of ischemia that were not visualized on preoperative scans. Discrete neurologic deficits were observed in only two (3.9%) of these patients. Deficits were transient and disappeared within 72 h. CONCLUSION: Our findings underscore MRI's capacity for visualizing perioperative ischemic events. Moreover, MRI provides evidence of clinically asymptomatic embolisms that occur perioperatively.     

Direct comparison of 3D spiral vs. Cartesian gradient-echo coronary magnetic resonance angiography.

While 3D thin-slab coronary magnetic resonance angiography (MRA) has traditionally been performed using a Cartesian acquisition scheme, spiral k-space data acquisition offers several potential advantages. However, these strategies have not been directly compared in the same subjects using similar methodologies. Thus, in the present study a comparison was made between 3D coronary MRA using Cartesian segmented k-space gradient-echo and spiral k-space data acquisition schemes. In both approaches the same spatial resolution was used and data were acquired during free breathing using navigator gating and prospective slice tracking. Magnetization preparation (T(2) preparation and fat suppression) was applied to increase the contrast. For spiral imaging two different examinations were performed, using one or two spiral interleaves, during each R-R interval. Spiral acquisitions were found to be superior to the Cartesian scheme with respect to the signal-to-noise ratio (SNR) and contrast-to-noise-ratio (CNR) (both P < 0.001) and image quality. The single spiral per R-R interval acquisition had the same total scan duration as the Cartesian acquisition, but the single spiral had the best image quality and a 2.6-fold increase in SNR. The double-interleaf spiral approach showed a 50% reduction in scanning time, a 1.8-fold increase in SNR, and similar image quality when compared to the standard Cartesian approach. Spiral 3D coronary MRA appears to be preferable to the Cartesian scheme. The increase in SNR may be "traded" for either shorter scanning times using multiple consecutive spiral interleaves, or for enhanced spatial resolution.     

Desmoplastic fibroma of the proximal ulna

A young man presented with desmoplastic fibroma in the proximal ulna. This rare tumour was treated by curettage and bone grafting.     

Serum levels of CD14 in neonatal sepsis by Gram-positive and Gram-negative bacteria

The purpose of this study is to measure soluble CD14 (sCD14) levels in sera from newborn with sepsis, to compare it with other markers, and to study its evolution in Gram-negative and Gram-positive sepsis. Forty normal newborns were included (26 were full term and 14 were preterm infants), 20 babies had a positive blood culture (11 Gram-positive and 9 Gram-negative) and 16 cases were suspected of having sepsis based on clinical and laboratory findings, but a negative blood culture. Interleukin-6 (IL-6), sCD14, and tumour necrosis factor-α (TNFα) were measured by enzyme immunoassay, and fibronectin (FN) and C-reactive protein (CRP) by radial immunodiffusion. Neonates with a positive blood culture had increased levels of sCD14(3.20 ± 1.26μgml^-1, p < 0.001), CRP(69 ± 46 μgml^-1, p < 0.001)and IL-6 (134 ± 150 pg ml^-1, p < 0.001), and decreased values of FN (12.3 ± 6.6 mg ml^-1, p < 0.001). TNFα levels were also high (160 ± 37 pg ml^-1), but this increase was not statistically significant. Newborn infants suspected of having sepsis but a negative blood culture had similar but milder abnormalities. Soluble CD 14 levels correlated with CRP values; however, there was no correlation between sCD 14, TNFα and IL-6. Neonates with sepsis by Gram-positive bacteria had lower sCD14 levels than patients with Gram-negative sepsis (2.63 ± 1.2 versus 4.04 ± 1.0μgml^-1, p < 0.05). In conclusion, the sCD14 level is increased in newborn infants with sepsis, and this is higher in infections by Gram-negative bacteria, suggesting a different contribution of monocyte and macrophage cells. In contrast, IL-6, TNFα, CRP and FN values are similar in infections by Gram-positive and Gram-negative bacteria.     

Social factors associated with AIDS and SARS

We conducted a survey of 928 New York City area residents to assess knowledge and worry about AIDS and SARS. Specific sociodemographic groups of persons were more likely to be less informed and more worried about contracting the diseases.