Ferromagnetic materials in patients: detection before MR imaging

A number of surgical clips and other metallic materials embedded within patients have ferromagnetic properties that present a potential hazard when in the strong fields associated with magnetic resonance imaging. Several types of magnetometers and metal detectors were investigated as possible pre-imaging screening devices. The sensitivities and costs of these devices are given.     

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Current aspects of forensic lawFrom October 2004 to March 2005

     

Attempted replication of reported chronic obstructive pulmonary disease candidate gene associations

Case-control studies have successfully identified many significant genetic associations for complex diseases, but lack of replication has been a criticism of case-control genetic association studies in general. We selected 12 candidate genes with reported associations to chronic obstructive pulmonary disease (COPD) and genotyped 29 polymorphisms in a family-based study and in a case-control study. In the Boston Early-Onset COPD Study families, significant associations with quantitative and/or qualitative COPD-related phenotypes were found for the tumor necrosis factor (TNF)-alpha -308G>A promoter polymorphism (P < 0.02), a coding variant in surfactant protein B (SFTPB Thr131Ile) (P = 0.03), and the (GT)(31) allele of the heme oxygenase (HMOX1) promoter short tandem repeat (P = 0.02). In the case-control study, the SFTPB Thr131Ile polymorphism was associated with COPD, but only in the presence of a gene-by-environment interaction term (P = 0.01 for both main effect and interaction). The 30-repeat, but not the 31-repeat, allele of HMOX1 was associated (P = 0.04). The TNF -308G>A polymorphism was not significant. In addition, the microsomal epoxide hydrolase "fast" allele (EPHX1 His139Arg) was significantly associated in the case-control study (P = 0.03). Although some evidence for replication was found for SFTPB and HMOX1, none of the previously published COPD genetic associations was convincingly replicated across both study designs.     

The effects of low-intensity ultrasound on medial collateral ligament healing in the rabbit model

BACKGROUND: Ruptured medial collateral ligaments are capable of healing over time, but biomechanical and biochemical properties remain inferior to normal tissue. Low-intensity ultrasound may improve healing. HYPOTHESIS: Medial collateral ligaments treated with ultrasound will demonstrate superior healing. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-one late-adolescent male rabbits underwent bilateral ligament transection. One ligament from each rabbit received ultrasound treatment every other day for 6 total treatments. Contralateral ligaments received sham treatments. After 3 or 6 weeks, ligaments were evaluated biomechanically and assayed for collagen concentration and the relative proportions of types I and III collagen. RESULTS: Areas of sonicated specimens were significantly larger (10.6% +/- 4.90%) at 6 weeks. Ultimate load (39.5% +/- 17.0%), ultimate displacement (24.5% +/- 8.0%), and energy absorption (69.1% +/- 22.0%) were significantly higher for sonicated specimens at 6 weeks. No significant biomechanical differences were observed at 3 weeks. The relative proportion of type I collagen was significantly higher in sonicated ligaments at 3 weeks (8.61% +/- 4.0%) and 6 weeks (6.91% +/- 3.0%). No significant differences in collagen concentration were observed at either 3 or 6 weeks. CONCLUSION: Subtle improvement with ultrasound treatment may be apparent by 3 weeks after injury, suggested by increased proportion of type I collagen. Ultrasound appears to improve some structural properties and to modestly increase scar cross-sectional area and type I collagen present at 6 weeks after injury in this model. CLINICAL RELEVANCE: Ultrasound treatments after ligament injury may facilitate earlier return to activities and decrease risk of reinjury.     

Tolerance of MRI vs. SPECT myocardial perfusion studies--a patient survey

PURPOSE: To compare patients' perceived satisfaction and tolerance of magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) myocardial perfusion imaging. MATERIALS AND METHODS: A questionnaire was sent retrospectively to 41 patients who had undergone both SPECT and MRI myocardial perfusion scans at our institution. The questionnaire assessed SPECT and MRI separately, and in a separate section compared the tests directly. The answers were scored and analyzed for statistical significance by the use of Wilcoxon signed-ranks and chi2 tests. RESULTS: Thirty-five completed questionnaires were returned. In a direct comparison, 12 patients (34%) preferred MRI overall, nine (26%) preferred SPECT, and 14 (40%) expressed no preference. The ratings for the overall comfort of the scans were similar, with a score of 5.8 for SPECT and 5.7 for MRI (on a scale of 1-10). More patients stated a preference for MRI on scan comfort, duration, and safety (no statistical significance), but it was less well rated than SPECT for space on the scanner (P = 0.008). Three patients (9%) stated that they would not have an MRI scan again, while two patients (6%) said they would not repeat a SPECT scan. CONCLUSION: MRI myocardial perfusion imaging represents an acceptable alternative to SPECT with respect to patient tolerance and satisfaction.     

Gait termination in young and older adults: effects of stopping stimulus probability and stimulus delay

Sixteen young (25±2.6 years) and 16 older individuals (69±4.4 years) walked normally then terminated walking rapidly. A visual stopping stimulus was presented 10 ms following ground contact (short delay) and in another condition, at 450 ms prior to toe-off (long delay). Stimulus probability was either high (80% of trials) or low (10%). The younger group stopped faster (463 vs. 574 ms) despite also walking faster (1.29 vs. 1.17 m s⁻¹). Longer delay decreased one-step responses but older participants used significantly more (slower) two-step stopping, which increased stopping time and distance. The additional step may have been pre-planned to maintain medial–lateral stability.     

COLAL-PRED Alizyme

COLAL-PRED (prednisolone sodium metasulfobenzoate), which is targeted to the colon by COLAL colonic drug delivery technology, is being developed by Alizyme for the potential treatment of inflammatory bowel disease. Alizyme expect to initiate a phase III trial in 2005.