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Background: Osteoporosis (OP) and osteomalacia (OM) are metabolic bone diseases characterized by mineral and matrix density changes. Quantitative bone matrix density differentiates OM from OP. MRI is a noninvasive and nonionizing imaging technique that can measure bone matrix density quantitatively in ex vivo and in vivo., Purpose: To demonstrate water + fat suppressed 1 H MRI to compute bone matrix density in ex vivo rat femurs in the preclinical model., Study Type: Prospective., Animal Model: Fifteen skeletally mature female Sprague-Dawley rats, five per group (normal, ovariectomized (OVX), partially nephrectomized/vitamin D (Vit-D) deficient), 250-275 g, ∼15 weeks old., Field Strength/sequence: 7T, zero echo time sequence with water + fat (VAPOR) suppression capability, μCT imaging, and gravimetric measurements., Assessment: Cortical and trabecular bone segments from normal and disease models were scanned in the same coil along with a dual calibration phantom for quantitative assessment of bone matrix density., Statistical Tests: ANOVA and linear regression were used for data analysis, with P-values <0.05 statistically significant., Results: The MRI-derived three-density PEG pellet densities have a strong linear relationship with physical density measures (r 2  = 0.99). The Vit-D group had the lowest bone matrix density for cortical bone (0.47 ± 0.16 g cm -3 ), whereas the OVX had the lowest bone matrix density for trabecular bone (0.26 ± 0.04 g cm -3 ). Gravimetry results confirmed these MRI-based observations for Vit-D cortical (0.51 ± 0.07 g cm -3 ) and OVX trabecular (0.26 ± 0.03 g cm -3 ) bone groups., Data Conclusion: Rat femur images were obtained using a modified pulse sequence and a custom-designed double-tuned ( 1 H/ 31 P) transmit-receive solenoid-coil on a 7T preclinical MRI scanner. Phantom experiments confirmed a strong linear relation between MRI-derived and physical density measures and quantitative bone matrix densities in rat femurs from normal, OVX, and Vit-D deficient/partially nephrectomized animals were computed., Level of Evidence: 2 TECHNICAL EFFICACY: Stage 2., (© 2024 International Society for Magnetic Resonance in Medicine.)

We measured the total daily urinary cortisol produced by each of 8 patients with multiple sclerosis during intravenous therapy with adrenocorticotropic hormone (ACTH). Results indicated marked daily variation from patient to patient as well as in the same patient, suggesting that ACTH infusions do not result in reliable, consistent, high-level production of cortisol. We attempted to express the quantity of cortisol produced as an equivalent amount or oral prednisone. This comparison is difficult to make; but, given certain assumptions, the figures suggest that 40 U or 80 U ACTH infusions do not elicit the quantities of steroid generally considered to be indicated for the therapy of major allergic, autoimmune, or neoplastic diseases.

Operating room personnel were studied for evidence of acute reversible or chronic cumulative cognitive dysfunction as measured by psychometric testing. In comparison with matched controls, no acute reversible deficits were noted in a relatively unpolluted operating room environment. There were only 2 marginally significant test differences between the control and operating room groups; however, control subjects did better than operating room personnel on 16 of 18 tests at both the beginning and end of the work week. Analyses of the deficit patterns and correlations with years of operating room exposure only weakly support the hypothesis that the test differences are due to toxic exposure.