Miriam Bredella
Publications
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2.62Impact points
Waist to hip ratio and trunk to extremity fat (DXA) are better surrogates for IMCL and for visceral fat respectively than for subcutaneous fat in adolescent girls.
Nutrition & metabolism. 01/2010; 7:86.
Increased visceral adipose tissue (VAT) and intramyocellular lipids (IMCL) are associated with increased metabolic risk. Clinical and DXA body composition measures that are associated with VAT are generally even more strongly associated with subcutaneous adipose tissue (SAT) reflecting general adipo... [more] Increased visceral adipose tissue (VAT) and intramyocellular lipids (IMCL) are associated with increased metabolic risk. Clinical and DXA body composition measures that are associated with VAT are generally even more strongly associated with subcutaneous adipose tissue (SAT) reflecting general adiposity, and thus are not specific for VAT. Measures more strongly associated with VAT than SAT (thus more specific for VAT), and predictors of IMCL have not been reported. We studied 30 girls 12-18 years; 15 obese, 15 normal-weight. The following were assessed: (1) anthropometric measures: waist circumference at the umbilicus and iliac crest (WC-UC and WC-IC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), (2) DXA measures: total fat, percent body fat (PBF), percent trunk fat (PTF), trunk-to-extremity fat ratio (TEFR), (3) MRI and 1H-MRS: VAT and SAT (L4-L5), soleus-IMCL. Group as a whole: WC, trunk fat and PBF were more strongly associated with SAT than VAT; none were specific for VAT. In contrast, PTF and TEFR were more significantly associated with VAT (r = 0.83 and 0.81 respectively, p <0.0001 for both) than SAT (r = 0.77 and 0.75, p < 0.0001 for both). Strongest associations of S-IMCL were with WHR (r = 0.66, p = 0.0004). Subgroup analysis: In obese girls, WHR and WHtR were more strongly correlated with VAT (r = 0.62 and 0.82, p = 0.04 and 0.001) than SAT (r = 0.41 and 0.73, p not significant and 0.007), and for DXA measures, PTF and TEFR were more significantly associated with VAT (r = 0.70 and 0.72, p = 0.007 and 0.006) than SAT (r = 0.52 and 0.53, p = 0.07 and 0.06). In controls, PTF and TEFR were more strongly correlated with VAT (r = 0.79, p = 0.0004 for both) than SAT (r = 0.71 and 0.72, p = 0.003 for both). WHR was associated with IMCL in obese girls (r = 0.78, p = 0.008), but not controls. Overall, WHR (anthropometry), and PTF and TEFR (DXA) are good surrogates for IMCL and for visceral fat respectively in adolescent girls.
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1.57Impact points
Reproducibility of trabecular structure analysis using flat-panel volume computed tomography.
Skeletal radiology. 06/2009;
PURPOSE: To determine inter-scan, inter-reader and intra-reader variability of trabecular structure analysis using flat-panel volume computed tomography (fp-VCT) in cadaver knee specimens. METHODS: Five explanted knee specimens were imaged at three different time points using fp-VCT. Four parameters... [more] PURPOSE: To determine inter-scan, inter-reader and intra-reader variability of trabecular structure analysis using flat-panel volume computed tomography (fp-VCT) in cadaver knee specimens. METHODS: Five explanted knee specimens were imaged at three different time points using fp-VCT. Four parameters that quantify trabecular bone structure of the proximal tibia were measured by two observers at two different time points. Bland-Altman analysis was used to compute the inter-scan, inter-observer and intra-observer variability. RESULTS: Inter-scan variability was low, with a mean difference of 0% and a standard deviation less than 8.4% for each of the four parameters. The inter-observer and intra-observer variability was less than 2.8% +/- 8.5%. CONCLUSION: Fp-VCT is a method for assessing trabecular structure parameters with low inter-scan, inter-reader and intra-reader variability.
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1.57Impact points
Medial patellar ossification after patellar instability: a radiographic finding indicative of prior patella subluxation/dislocation.
Skeletal radiology. 03/2009;
OBJECTIVE: To describe the correlation between medial patellar ossification and prior patella subluxation and/or dislocation. MATERIALS AND METHODS: A retrospective billing database search identified 544 patients who had been diagnosed with patellar instability over a 13-year period. One hundred twe... [more] OBJECTIVE: To describe the correlation between medial patellar ossification and prior patella subluxation and/or dislocation. MATERIALS AND METHODS: A retrospective billing database search identified 544 patients who had been diagnosed with patellar instability over a 13-year period. One hundred twenty-eight patients met the inclusion criteria. After review by a staff orthopedic surgeon and two musculoskeletal radiologists, 28 patients were found to have medial patellar ossification. The size and location of medial patellar ossification was recorded. RESULTS: Of the 28 patients (20 males, eight females, age 13-66 years, mean 28 years) who were found to have medial patellar ossification, 22 had radiographs, 16 had magnetic resonance imaging, and ten had both. The medial patellar ossification ranged in size from 2 to 18 mm with an average of 6.8 mm. Twelve were located in the medial patellofemoral ligament (MPFL), 14 in the medial joint capsule, and two in both the MPFL and joint capsule. Twenty-seven of 28 patients had a single ossification, and one patient had two ossifications. The timing from injury to first imaging of the lesion ranged from 10 days to a chronic history (>/=35 years) of patellar instability. CONCLUSION: Medial patellar ossification correlates with a history of prior patella subluxation and/or dislocation. The medial ossification can be seen within the MPFL or the medial joint capsule, suggesting remote injury to these structures. The presence of this lesion will prompt physicians to evaluate for patellar instability.
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4.40Impact points
Lower Growth Hormone and Higher Cortisol are Associated with Greater Visceral Adiposity, Intramyocellular Lipids and Insulin Resistance in Overweight Girls.
American journal of physiology. Endocrinology and metabolism. 07/2008;
Background: Although overweight adolescents have markedly altered body composition, insulin sensitivity and lipids, hormonal associations with these parameters have not been well characterized. Growth hormone (GH) deficiency and hypercortisolemia predispose to abdominal adiposity and insulin resista... [more] Background: Although overweight adolescents have markedly altered body composition, insulin sensitivity and lipids, hormonal associations with these parameters have not been well characterized. Growth hormone (GH) deficiency and hypercortisolemia predispose to abdominal adiposity and insulin resistance, and GH secretion is decreased in obese adults. Objective: We hypothesized that low peak GH on the GHRH-arginine stimulation test, and high cortisol in overweight adolescents would be associated with higher regional fat, insulin resistance and lipids. Design/Methods: We examined the following in 15 overweight girls and 15 bone-age-matched controls 12-18 years: (i) body composition using DXA and MR [visceral and subcutaneous adipose tissue (VAT and SAT) at L 4-5, and soleus-intramyocellular lipid (IMCL) (1H-MRS)], (ii) peak GH on the GHRH-arginine stimulation test, (iii) mean overnight GH and cortisol, (iv) 24-hour urine free cortisol (UFC), (v) fasting lipids, and (vi) an OGTT. Stepwise regression was the major tool employed to determine relationships between measured parameters. Results: Log peak GH on the GHRH-arginine test was lower (p=0.03) and log UFC higher (p=0.02) in overweight girls. Log mean cortisol (overnight sampling) was associated positively with SAT, and with BMI-SDS accounted for 92% of its variability, whereas log peak GH and BMI-SDS accounted for 88% of VAT variability, and log peak GH for 34% of the IMCL variability. Log mean cortisol was independently associated with log HOMA-IR, LDL and HDL and explained 49- 59% of the variability. Conclusions: Lower peak GH and higher UFC in overweight girls are associated with visceral adiposity, insulin resistance and lipids. Key words: Obesity, HOMA-IR, Leptin, Body composition, Lipids.
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1.57Impact points
Musculoskeletal applications of flat-panel volume CT.
Skeletal radiology. 05/2008;
Flat-panel volume computed tomography (fpVCT) is a recent development in imaging. We discuss some of the musculoskeletal applications of a high-resolution flat-panel CT scanner. FpVCT has four main advantages over conventional multidetector computed tomography (MDCT): high-resolution imaging; volume... [more] Flat-panel volume computed tomography (fpVCT) is a recent development in imaging. We discuss some of the musculoskeletal applications of a high-resolution flat-panel CT scanner. FpVCT has four main advantages over conventional multidetector computed tomography (MDCT): high-resolution imaging; volumetric coverage; dynamic imaging; omni-scanning. The overall effective dose of fpVCT is comparable to that of MDCT scanning. Although current fpVCT technology has higher spatial resolution, its contrast resolution is slightly lower than that of MDCT (5-10HU vs. 1-3HU respectively). We discuss the efficacy and potential utility of fpVCT in various applications related to musculoskeletal radiology and review some novel applications for pediatric bones, soft tissues, tumor perfusion, and imaging of tissue-engineered bone growth. We further discuss high-resolution CT and omni-scanning (combines fluoroscopic and tomographic imaging).
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1.57Impact points
MR imaging of the elbow in baseball pitchers.
Skeletal radiology. 03/2008; 37(2):115-21.
Baseball pitcher throwing biomechanics are important to understanding the pathophysiology and magnetic resonance (MR) imaging appearances of injuries in baseball pitchers. Baseball pitchers experience repetitive excessive valgus forces at the elbow. Typical injuries are secondary to medial joint dis... [more] Baseball pitcher throwing biomechanics are important to understanding the pathophysiology and magnetic resonance (MR) imaging appearances of injuries in baseball pitchers. Baseball pitchers experience repetitive excessive valgus forces at the elbow. Typical injuries are secondary to medial joint distraction, lateral joint compression, and rotatory forces at the olecranon. MR imaging is useful for evaluation of the elbow in baseball pitchers.
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1.57Impact points
Spectrum of shoulder injuries in the baseball pitcher.
Skeletal radiology. 11/2007;
This review describes a range of shoulder injuries experienced by baseball pitchers. It is estimated that more than 57% of pitchers suffer some form of shoulder injury during a playing season. Knowledge of the overhead throwing cycle is crucial for our understanding of these shoulder injuries. Baseb... [more] This review describes a range of shoulder injuries experienced by baseball pitchers. It is estimated that more than 57% of pitchers suffer some form of shoulder injury during a playing season. Knowledge of the overhead throwing cycle is crucial for our understanding of these shoulder injuries. Baseball pitchers are prone to rotator cuff tears from tensile overload and impingement. Glenoid labrum degeneration or tears are also common, due to overuse syndrome (micro-instability), internal impingement and microtrauma. An understanding of the lesions involved in overhead throwing is crucial in baseball pitchers, as long-term disability can result from these injuries, sometimes with severe financial consequences to the player.
Following (3)
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Madhusmita Misra
Massachusetts General Hospital -
Christianne Leidecker
Siemens -
Nara Mendes
Massachusetts General Hospital
7
Publications
7
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