Basal ganglia intensity indices and diffusion weighted imaging in manganese-exposed welders.

OBJECTIVES: Manganese exposure leads to diffuse cerebral metal deposition with the highest concentration in the globus pallidus associated with increased T1-weighted MRI signal. T1 signal intensity in extra-pallidal basal ganglia (caudate and putamen) has not been studied in occupationally exposed workers. Diffusion weighted imaging is a non-invasive measure of neuronal damage and may provide a quantification of neurotoxicity associated with welding and manganese exposure. This study investigated extra-pallidal T1 basal ganglia signal intensity as a marker of manganese exposure and basal ganglia diffusion weighted imaging abnormalities as a potential marker of neurotoxicity. METHODS: A 3T MR case:control imaging study was performed on 18 welders and 18 age- and gender-matched controls. Basal ganglia regions of interest were identified for each subject. T1-weighted intensity indices and apparent diffusion coefficients were generated for each region. RESULTS: All regional indices were higher in welders than controls (p ≤ 0.05). Combined basal ganglia (ρ = 0.610), caudate (ρ = 0.645), anterior (ρ = 0.595) and posterior putamen (ρ = 0.511) indices were more correlated with exposure than pallidal (ρ = 0.484) index. Welder apparent diffusion coefficient values were lower than controls for globus pallidus (p = 0.03) and anterior putamen (p = 0.004). CONCLUSIONS: Welders demonstrated elevated T1 indices throughout the basal ganglia. Combined basal ganglia, caudate and putamen indices were more correlated with exposure than pallidal index suggesting more inclusive basal ganglia sampling results in better exposure markers. Elevated indices were associated with diffusion weighted abnormalities in the pallidum and anterior putamen suggesting neurotoxicity in these regions.

Radiofrequency wire technique and image fusion in the creation of an endovascular bypass to treat chronic central venous occlusion.

The goal of this case report was to demonstrate the feasibility, safety, and efficacy of image fusion software to treat symptomatic central venous occlusion with radiofrequency wire after failure of conventional endovascular techniques. The complex and chronic central venous occlusion was successfully treated without complications. The combination of these techniques provided an endovascular solution and could be considered in select cases.

Cerebral mitochondrial metabolism in early Parkinson's disease.

Abnormal cerebral energy metabolism owing to dysfunction of mitochondrial electron transport has been implicated in the pathogenesis of Parkinson's disease (PD). However, in vivo data of mitochondrial dysfunction have been inconsistent. We directly investigated mitochondrial oxidative metabolism in vivo in 12 patients with early, never-medicated PD and 12 age-matched normal controls by combined measurements of the cerebral metabolic rate of oxygen (CMRO(2)) and the cerebral metabolic rate of glucose (CMRglc) with positron emission tomography. The primary analysis showed a statistically significant 24% increase in bihemispheric CMRO(2) and no change in CMRO(2)/CMRglc. These findings are inconsistent with a defect in mitochondrial oxidative phosphorylation owing to reduced activity of the mitochondrial electron transport system (ETS). Because PD symptoms were already manifest, deficient energy production owing to a reduced activity of the mitochondrial ETS cannot be a primary mechanism of neuronal death in early PD. Alternatively, this general increase in CMRO(2) could be due not to an increased metabolic demand but to an uncoupling of ATP production from oxidation in the terminal stage of oxidative phosphorylation. Whether this is the case in early PD and whether it is important in the pathogenesis of PD will require further study.

Just, in time: ethical implications of serial predictions of death and morbidity for ventilated premature infants.

OBJECTIVES: For a cohort of extremely premature, ventilated, newborn infants, we determined the power of either serial caretaker intuitions of "die before discharge" or serial illness severity scores to predict the outcomes of death in the NICU or neurologic performance at corrected age of 2 years. METHODS: We identified 268 premature infants who were admitted to our NICU in 1999-2004 and required mechanical ventilation. For each infant on each day of mechanical ventilation, we asked nurses, residents, fellows, and attending physicians the following question: "Do you think this child is going to live to go home or die before hospital discharge?" In addition, we calculated illness severity scores until either death or extubation. RESULTS: A total of 17,066 intuition profiles were obtained on 5609 days of mechanical ventilation in the NICU. One hundred (37%) of 268 profiled infants had > or = 1 intuition of die before discharge. Only 33 infants (33%) with an intuition of die actually died in the NICU. Of 48 infants with even 1 day of corroborated intuition of die in the NICU, only 7 (14%) were alive with both Mental Developmental Index and Psychomotor Developmental Index scores of > 69, and only 2 (4%) were alive with both Mental Developmental Index and Psychomotor Developmental Index Scores of > 79 at corrected age of 2 years. On day of life 1, the Score for Neonatal Acute Physiology II value for nonsurvivors (38.2 +/- 18.1) was significantly higher than that for survivors (26.3 +/- 12.7). However, this difference decreased steadily over time as scores improved for both groups. CONCLUSIONS: Illness severity scores become progressively less helpful over time in distinguishing infants who will either die in the NICU or survive with low Mental Developmental Index/Psychomotor Developmental Index scores. Serial caretaker intuitions of die before discharge also fail to identify prospective nonsurviving infants. However, corroborated intuitions of die before discharge identify a subset of infants whose likelihood of surviving to 2 years with both MDI and PDI > 80 is approximately 4%.