Association of smoking with abdominal adipose deposition and muscle composition in Coronary Artery Risk Development in Young Adults (CARDIA) participants at mid-life: A population-based cohort study.

BACKGROUND: Smokers have lower risk of obesity, which some consider a "beneficial" side effect of smoking. However, some studies suggest that smoking is simultaneously associated with higher central adiposity and, more specifically, ectopic adipose deposition. Little is known about the association of smoking with intermuscular adipose tissue (IMAT), an ectopic adipose depot associated with cardiovascular disease (CVD) risk and a key determinant of muscle quality and function. We tested the hypothesis that smokers have higher abdominal IMAT and lower lean muscle quality than never smokers. METHODS AND FINDINGS: We measured abdominal muscle total, lean, and adipose volumes (in cubic centimeters) and attenuation (in Hounsfield units [HU]) along with subcutaneous (SAT) and visceral adipose tissue (VAT) volumes using computed tomography (CT) in 3,020 middle-aged Coronary Artery Risk Development in Young Adults (CARDIA) participants (age 42-58, 56.3% women, 52.6% white race) at the year 25 (Y25) visit. The longitudinal CARDIA study was initiated in 1985 with the recruitment of young adult participants (aged 18-30 years) equally balanced by female and male sex and black and white race at 4 field centers located in Birmingham, AL, Chicago, IL, Minneapolis, MN, and Oakland, CA. Multivariable linear models included potential confounders such as physical activity and dietary habits along with traditional CVD risk factors. Current smokers had lower BMI than never smokers. Nevertheless, in the fully adjusted multivariable model with potential confounders, including BMI and CVD risk factors, adjusted mean (95% CI) IMAT volume was 2.66 (2.55-2.76) cm3 in current smokers (n = 524), 2.36 (2.29-2.43) cm3 in former smokers (n = 944), and 2.23 (2.18-2.29) cm3 in never smokers (n = 1,552) (p = 0.007 for comparison of former versus never smoker, and p < 0.001 for comparison of current smoker versus never and former smoker). Moreover, compared to participants who never smoked throughout life (41.6 [41.3-41.9] HU), current smokers (40.4 [39.9-40.9] HU) and former smokers (40.8 [40.5-41.2] HU) had lower lean muscle attenuation suggesting lower muscle quality in the fully adjusted model (p < 0.001 for comparison of never smokers with either of the other two strata). Among participants who had ever smoked, pack-years of smoking exposure were directly associated with IMAT volume (ß [95% CI]: 0.017 [0.010-0.025]) (p < 0.001). Despite having less SAT, current smokers also had higher VAT/SAT ratio than never smokers. These findings must be viewed with caution as residual confounding and/or reverse causation may contribute to these associations. CONCLUSIONS: We found that, compared to those who never smoked, current and former smokers had abdominal muscle composition that was higher in adipose tissue volume, a finding consistent with higher CVD risk and age-related physical deconditioning. These findings challenge the belief that smoking-associated weight loss or maintenance confers a health benefit.

Automated Characterization of Body Composition and Frailty with Clinically Acquired CT.

Quantification of fat and muscle on clinically acquired CT scans is critical for determination of body composition, a key component of health. Manual tracing has been regarded as the gold standard method of body segmentation; however, manual tracing is time-consuming. Many semi-automated/automated algorithms have been proposed to avoid the manual efforts. Previous efforts largely focused on segmenting 2D cross-sectional images (e.g., at L3/T4 vertebra locations) rather than on the whole-body volume. In this paper, we propose a fully automated 3D body composition estimation framework for segmenting the muscle and fat from abdominal CT scans. The 3D whole body segmentations were reconstructed from a slice-wise multi-atlas label fusion (MALF) based framework. First, we used a low-dimensional atlas representation to estimate each class for each axial slice. Second, the abdominal wall and psoas muscle were segmented by combining MALF with active shape models and deformable models. Third, skeletal muscle, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured to assess the areas of muscle and fat tissue. The proposed method was compared to manual segmentation and demonstrated high accuracy. Then, we evaluated the approach on 40 CT scans comparing the new method to a prior atlas-based segmentation method and achieved 0.854, 0.740, 0.887 and 0.933 on Dice similarity index for the skeletal muscle, psoas muscle, VAT and SAT, respectively. Compared with the baseline, our method showed significantly (p < 0.001) higher accuracy on skeletal muscle, VAT and SAT estimation.

Lymphedema evaluation using noninvasive 3T MR lymphangiography.

PURPOSE: To exploit the long 3.0T relaxation times and low flow velocity of lymphatic fluid to develop a noninvasive 3.0T lymphangiography sequence and evaluate its relevance in patients with lymphedema. MATERIALS AND METHODS: A 3.0T turbo-spin-echo (TSE) pulse train with long echo time (TEeffective = 600 msec; shot-duration = 13.2 msec) and TSE-factor (TSE-factor = 90) was developed and signal evolution simulated. The method was evaluated in healthy adults (n = 11) and patients with unilateral breast cancer treatment-related lymphedema (BCRL; n = 25), with a subgroup (n = 5) of BCRL participants scanned before and after manual lymphatic drainage (MLD) therapy. Maximal lymphatic vessel cross-sectional area, signal-to-noise-ratio (SNR), and results from a five-point categorical scoring system were recorded. Nonparametric tests were applied to evaluate study parameter differences between controls and patients, as well as between affected and contralateral sides in patients (significance criteria: two-sided P < 0.05). RESULTS: Patient volunteers demonstrated larger lymphatic cross-sectional areas in the affected (arm = 12.9 ± 6.3 mm2 ; torso = 17.2 ± 15.6 mm2 ) vs. contralateral (arm = 9.4 ± 3.9 mm2 ; torso = 9.1 ± 4.6 mm2 ) side; this difference was significant both for the arm (P = 0.014) and torso (P = 0.025). Affected (arm: P = 0.010; torso: P = 0.016) but not contralateral (arm: P = 0.42; torso: P = 0.71) vessel areas were significantly elevated compared with control values. Lymphatic cross-sectional areas reduced following MLD on the affected side (pre-MLD: arm = 8.8 ± 1.8 mm2 ; torso = 31.4 ± 26.0 mm2 ; post-MLD: arm = 6.6 ± 1.8 mm2 ; torso = 23.1 ± 24.3 mm2 ). This change was significant in the torso (P = 0.036). The categorical scoring was found to be less specific for detecting lateralizing disease compared to lymphatic-vessel areas. CONCLUSION: A 3.0T lymphangiography sequence is proposed, which allows for upper extremity lymph stasis to be detected in ∼10 minutes without exogenous contrast agents. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1349-1360.

Sarcopenia Does Not Affect Survival or Outcomes in Soft-Tissue Sarcoma.

Background and Objective. Sarcopenia is associated with decreased survival and increased complications in carcinoma patients. We hypothesized that sarcopenic soft-tissue sarcoma (STS) patients would have decreased survival, increased incidence of wound complications, and increased length of postresection hospital stay (LOS). Methods. A retrospective, single-center review of 137 patients treated surgically for STS was conducted. Sarcopenia was assessed by measuring the cross-sectional area of bilateral psoas muscles (total psoas muscle area, TPA) at the level of the third lumbar vertebrae on a pretreatment axial computed tomography scan. TPA was then adjusted for height (cm(2)/m(2)). The association between height-adjusted TPA and survival was assessed using Cox proportional hazard model. A logistical model was used to assess the association between height-adjusted TPA and wound complications. A linear model was used to assess the association between height-adjusted TPA and LOS. Results. Height-adjusted TPA was not an independent predictor of overall survival (p = 0.746). Patient age (p = 0.02) and tumor size (p = 0.009) and grade (p = 0.001) were independent predictors of overall survival. Height-adjusted TPA was not a predictor of increased hospital LOS (p = 0.66), greater incidence of postoperative infection (p = 0.56), or other wound complications (p = 0.14). Conclusions. Sarcopenia does not appear to impact overall survival, LOS, or wound complications in patients with STS.

Patient-specific imaging and missed tumors: a catastrophic outcome.

Patient-specific instrumentation (PSI) is a relatively new technology aimed at increasing the accuracy and efficiency of total knee arthroplasty (TKA). Its premise is reliant upon preoperative imaging techniques to acquire detailed measurements of a patient's distal femur and proximal tibia. Although a limited number of studies in the current literature have begun to critically evaluate this promising technology, a number of potential controversies exist. We present 2 patients with radiographic evidence of musculoskeletal neoplasms present on initial preoperative imaging that were not recognized prior to placement of patient-specific total knees. The expanding role of non-diagnostic imaging in TKA is examined, and we suggest guidelines for prevention of further devastating outcomes.

MRI techniques: a review and update for the orthopaedic surgeon.

MRI plays a critical role in all orthopaedic practices. A basic working knowledge of the most commonly used pulse sequences in musculoskeletal imaging and the appearance of normal tissues on those sequences is critical to confident MRI interpretation. The orthopaedic surgeon should be familiar with appropriate use of intravenous and intra-articular contrast and its limitations. Concepts key to MRI interpretation include image contrast and resolution, signal, noise, and pulse sequence. Recent advances in anatomic and functional imaging highlight the robust potential of MRI for musculoskeletal evaluation. As MRI technology evolves, the orthopaedic surgeon must stay current on these technologic advances to use this tool to its fullest potential.