Purpose To determine the reproducibility of proton MR spectroscopy (1H-MRS) for assessing vertebral bone marrow adiposity at 3 Tesla (T); to evaluate variation of marrow adiposity at different vertebral levels; and to demonstrate the feasibility of using 1H-MRS at 3 T for evaluating marrow adiposity in subjects with low bone density. Materials and Methods Single voxel MRS was acquired at vertebral body L1 to L4 at 3 T in 51 post-menopausal females including healthy controls (n = 13) and patients with osteoporosis/osteopenia (n = 38). Marrow fat contents were compared between vertebral levels and between groups using analysis of variance (ANOVA). Six subjects were scanned twice to evaluate technique reproducibility. Results The average coefficient of variation of vertebral marrow fat content quantification was 1.7%. Marrow fat content significantly increased from L1 to L4. The average fat content was significantly elevated in patients with osteoporosis/osteopenia and in patients with diabetes compared to controls, adjusted for age and body mass index (BMI) (P < 0.05). Conclusions In vivo MRS at high field strength provides reliable measurement of marrow adiposity with excellent reproducibility and can be a valuable tool for providing complementary information on bone quality and potentially also fracture risk.
Older women with type 2 diabetes mellitus (DM) have higher bone mineral density (BMD) but also have higher rates of fracture compared to those without DM. Limited evidence suggests that DM may also be associated with more rapid bone loss. To determine if bone loss rates differ by DM status in older women, we analyzed BMD data in the Study of Osteoporotic Fractures (SOF) between 1986 and 1998. SOF participants were women ≥65 years at baseline who were recruited from four regions in the U.S. DM was ascertained by self-report. BMD was measured with dual-energy x-ray absorptiometry (DXA) at baseline and at least one follow-up visit at the hip (N = 6624) and calcaneus (N = 6700) and, on a subset of women, at the spine (N = 396) and distal radius (N = 306). Annualized percent change in BMD was compared by DM status, using random effects models. Of 6,867 women with at least one follow-up DXA scan, 409 had DM at baseline. Mean age was 70.8 (SD 4.7) years. Baseline BMD was higher in women with DM at all measured sites. In models adjusted for age and clinic, women with prevalent DM lost bone more rapidly than those without DM at the femoral neck (−0.96 vs. −0.59%/year, p < 0.001), total hip (−0.98 vs. −0.70%/year, p < 0.001), calcaneus (−1.64 vs. −1.40%/year, p = 0.005), and spine (−0.33 vs. +0.33%/year, p = 0.033), but not at the distal radius (−0.97 vs. −0.90%/year, p = 0.91). These findings suggest that despite higher baseline BMD, older women with DM experience more rapid bone loss than those without DM at the hip, spine, and calcaneus, but not the radius. Higher rates of bone loss may partially explain higher fracture rates in older women with DM.
Acute Respiratory Distress Syndrome (ARDS) has been reported rarely in pheochromocytoma, occurring spontaneously or after therapy with 131I-meta-iodobenzylguanidine (131I-MIBG). Our objective was to determine whether proteinuria is associated with an increased risk of ARDS. This was a retrospective analysis of a prospective cohort study of 64 patients with metastatic pheochromocytoma or paraganglioma treated with 131I-MIBG on institutional protocols. Proteinuria was defined as at least one urinalysis positive for at least trace protein within 1 month prior to 131I-MIBG or within 1 month prior to spontaneous ARDS. Proportions were compared using Fisher's exact test. Urinalyses within the defined time period were available for 48 patients, 8 of whom had proteinuria. Of the 8 patients with proteinuria, 5 developed ARDS: 3 within 10 days following 131I-MIBG, two 6 months following 131I-MIBG. Both patients who developed ARDS 6 months after 131I-MIBG had proteinuria within 1 month before apparently spontaneous ARDS. None of the 40 patients whose urinalyses were all negative for protein developed ARDS. None of the 16 patients with missing urinalyses developed ARDS. Patients with antecedent proteinuria were more likely to develop ARDS than those without proteinuria (63% vs. 0%; p<0.0001). The following variables were not significantly associated with ARDS: 131I-MIBG activities administered, number of 131I-MIBG administrations, age, hypertension, or secretion of catecholamines or metanephrines. In patients with metastatic pheochromocytoma or paraganglioma, proteinuria is associated with ARDS and urine protein should be examined prior to administering 131I-MIBG.
We present the case of a 59-year-old woman with a history of plastic surgery at the forehead who complained of progressive indentations at the frontal skull. CT and MR scans revealed significant bone thinning, presenting as lytic skull lesions, which progressed over a period of 3 years. Biopsies were obtained from the lytic lesions and histology showed fibrotic tissue, synthetic residue of previous cosmetic procedure, and no evidence of infection or neoplasm. Progressive cranial bone resorption places the patient at increased risk for cerebral injury. This case highlights a potential complication after cosmetic facial surgery, with bony resorption resulting in both skull deformation and increased risk for cerebral injury.
We evaluated an African American woman referred in 1986 at age 33 years because of renal potassium and calcium wasting and chronic hip pain. She presented normotensive, hypokalemic, hypocalcemic, normophosphatemic, and hypercalciuric. Marked hyperparathyroidism was evident. Urinary cyclic adenosine monophosphate (cAMP) excretion did not increase in response to parathyroid hormone (PTH) infusion, indicating renal resistance to PTH. X-rays and bone biopsy revealed severe osteitis fibrosa cystica, confirming skeletal responsiveness to PTH. Renal potassium wasting, suppressed plasma renin activity, and elevated plasma and urinary aldosterone levels accompanied her hypokalemia, suggesting primary hyperaldosteronism. Hypokalemia resolved with spironolactone and, when combined with dietary sodium restriction, urinary calcium excretion fell and hypocalcemia improved, in accord with the known positive association between sodium intake and calcium excretion. Calcitriol and oral calcium supplements did not suppress the chronic hyperparathyroidism nor did they reduce aldosterone levels. Over time, hyperparathyroid bone disease progressed with pathologic fractures and persistent pain. In 2004, PTH levels increased further in association with worsening chronic kidney disease. Eventually hypercalcemia and hypertension developed. Localizing studies in 2005 suggested a left inferior parathyroid tumor. After having consistently declined, the patient finally agreed to neck exploration in January 2009. Four hyperplastic parathyroid glands were removed, followed immediately by severe hypocalcemia, attributed to ''hungry bone syndrome'' and hypoparathyroidism, which required prolonged hospitalization, calcium infusions, and oral calcitriol. Although her bone pain resolved, hyperaldosteronism persisted. ß
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