Xe gases were measured in the lungs of rabbits with elastase-induced emphysema and correlated against the mean chord length from lung histology. In vivo measurements were performed at baseline and 2, 4, 6, and 8 wk after instillation of elastase (mild and moderate emphysema groups) or saline (control group). ADCs were determined from acquisitions that used two b values. To investigate the effect of b value on the results, b-value pairs of 0 and 1.6 s/cm 2 and 0 and 4.0 s/cm 2 were used for 3 He, and b-value pairs of 0 and 5.0 s/cm 2 and 0 and 10.0 s/cm 2 were used for 129 Xe. At 8 wk after instillation, the rabbits were euthanized, and the lungs were analyzed histologically and morphometrically. ADCs for the rabbits in the control group did not change significantly from baseline to week 8, whereas ADCs for the rabbits in the emphysema groups increased significantly (P Ͻ 0.05) for all gas and b-value combinations except 129 Xe with the b-value pair of 0 and 5.0 s/cm 2 . The largest percent change in mean ADC from baseline to week 8 (15.3%) occurred with 3 He and the b-value pair of 0 and 1.6 s/cm 2 for rabbits in the moderate emphysema group. ADCs (all b values) were strongly correlated (r ϭ 0.62-0.80, P Ͻ 0.001) with mean chord lengths from histology. These results further support the ability of diffusion-weighted MRI with hyperpolarized gases to detect regional and global structural changes of emphysema within the lung.hyperpolarized gas magnetic resonance imaging; elastase MORE THAN 3,100,000 Americans suffer from emphysema, which is a component of chronic obstructive pulmonary disease (COPD). COPD and other forms of lower respiratory diseases, excluding asthma, represented the fourth-leading cause of death in the United States in 2002, claiming the lives of Ͼ124,000 people (1, 2). Pulmonary function tests are frequently used for the detection and assessment of emphysema. Patients with emphysema have a decreased expiratory flow rate, but 30% of lung capacity can be lost before changes appear in pulmonary function tests (22). Furthermore, the measurements are effort dependent, resulting in a relatively large intraindividual variability. High-resolution CT has been used to assess emphysematous change in the lung. In fact, CT was able to detect a decrease in the rate of decline of lung function in patients with ␣ 1 -antitrypsin deficiency who were treated with ␣ 1 -antitrypsin, whereas no significant change was seen with spirometry (20). Thus CT has been proposed as a potential biomarker for emphysema (3). Because of the tissue destruction that occurs in emphysema, emphysematous regions of the lung have less lung tissue per unit volume than normal lung, so they exhibit lower attenuation on CT. However, other processes in the lung can reduce CT attenuation, including reduced perfusion and air trapping (23). Furthermore, the relatively high radiation dose of a chest CT scan may limit its use for repeated scans in longitudinal studies and clinical trials (4). Hyperpolarized 3 He and 129 Xe are gaseous contrast agent...

OBJECTIVETo compare efficiency of nonmydriatic ultrawide field retinal imaging (UWFI) and nonmydriatic fundus photography (NMFP) in a diabetic retinopathy (DR) ocular telehealth program. RESEARCH DESIGN AND METHODSPatients in this retrospective, comparative cohort study underwent NMFP and UWFI between 1 November 2011 and 1 November 2012. Images were evaluated for DR and diabetic macular edema (DME) by certified graders using a standard protocol at a centralized reading center. Identification of DR, image evaluation time, and rate of ungradable eyes were compared. RESULTSNMFP and UWFI were performed in 1,633 and 2,170 consecutive patients, respectively. No statistically significant differences were found between groups regarding age, diabetes duration, sex, ethnicity, or insulin use. The ungradable rate per patient for DR (2.9 vs. 9.9%, P < 0.0001) and DME (3.8 vs. 8.8%, P < 0.0001) was lower with UWFI than with NMFP. With UWFI, the median image evaluation time per patient was reduced from 12.8 to 9.2 min (P < 0.0001). The identification of patients with DR (38.4 vs. 33.8%) and vision-threatening DR (14.5 vs. 11.9%) was increased with UWFI versus NMFP. In a consecutive subgroup of 502 eyes of 301 patients with DR, the distribution of peripheral retinal lesions outside Early Treatment Diabetic Retinopathy Study fields suggested a more severe DR level in 9.0% (45 eyes). CONCLUSIONSIn a standardized DR ocular telehealth program, nonmydriatic UWFI reduced the ungradable rate by 71% (to <3%) and reduced image evaluation time by 28%. DR was identified 17% more frequently after UWFI, and DR peripheral lesions suggested a more severe DR level in 9%. These data suggest that UWFI may improve efficiency of ocular telehealth programs evaluating DR and DME.

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Background: The effect of concussions on professional athletes has been investigated in many sports. However, few studies have evaluated concussions in National Basketball Association (NBA) players. Hypothesis: We hypothesized that concussion incidence has increased, yet the return-to-play (RTP) rate will remain high following the institution of the NBA concussion policy (NBACP). We also hypothesized that the incidence of repeat concussions will be similar to first occurrences and that player performance and game availability will not be significantly affected by sustaining a concussion. Study Design: Descriptive epidemiology study. Methods: Publicly available records were searched to identify all concussions from NBA seasons 1999-2000 to 2017-2018. Player demographics and information regarding career history were tabulated. Incidence of concussion and RTP timing were evaluated before and after institution of the NBACP (2011). Minutes per game and game score per minute were evaluated pre- versus postconcussion. Player availability and performance were also compared with an age-, body mass index–, position-, and experience-matched control group of players who did not sustain a concussion. Results: A total of 189 concussions were reported in the NBA from 1999 to 2018, with a mean ± SD incidence of 9.7 ± 7.3 concussions per season. Following implementation of the NBACP, incidence significantly increased from 5.7 ± 2.8 to 16.7 ± 7.5 concussions per season ( P = .007). All players returned to play following first-time concussion after missing 7.7 ± 8.6 days and 3.5 ± 4.1 games. RTP time was not significantly different after implementation of the NBACP (games missed, P = .24; days missed, P = .27), and there was no difference in concussion-free time interval ( P = .29). Game score per minute and minutes per game were not significantly affected by sustaining a concussion (both P > .05). Conclusion: Concussion incidence in NBA players is approximately 17 instances per season since the 2011 institution of a league-wide concussion policy. The number of reported concussions significantly increased following the policy, in line with trends seen in other professional sports leagues. Players have retained a high rate of RTP after 3 to 4 missed games. Player performance and availability are not affected by sustaining a concussion following successful RTP.

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Background: Low-load blood flow restriction (BFR) training has attracted attention as a potentially effective method of perioperative clinical rehabilitation for patients undergoing orthopaedic procedures. Purpose: To (1) compare the effectiveness of low-load BFR training in conjunction with a standard rehabilitation protocol, pre- and postoperatively, and non-BFR interventions in patients undergoing anterior cruciate ligament reconstruction (ACLR) and (2) evaluate protocols for implementing BFR perioperatively for patients undergoing ACLR. Study Design: Systematic review; Level of evidence, 2. Methods: A systematic review of the 3 medical literature databases was conducted to identify all level 1 and 2 clinical trials published since 1990 on BFR in patients undergoing ACLR. Patient demographics from included studies were pooled. Outcome data were documented, including muscle strength and size, and perceived pain and exertion. A descriptive analysis of outcomes from BFR and non-BFR interventions was performed. Results: A total of 6 studies (154 patients; 66.2% male; mean ± SD age, 24.2 ± 3.68 years) were included. Of these, 2 studies examined low-load BFR as a preoperative intervention, 1 of which observed a significant increase in muscle isometric endurance ( P = .014), surface electromyography of the vastus medialis ( P < .001), and muscle blood flow to the vastus lateralis at final follow-up ( P < .001) as compared with patients undergoing sham BFR. Four studies investigated low-load BFR as a postoperative intervention, and they observed significant benefits in muscle hypertrophy, as measured by cross-sectional area; strength, as measured by extensor torque; and subjective outcomes, as measured by subjective knee pain during session, over traditional low-load resistance training (all P < .05). BFR occlusion periods ranged from 3 to 5 minutes, with rest periods ranging from 45 seconds to 3 minutes. Conclusion: This systematic review found evidence on the topic of BFR rehabilitation after ACLR to be sparse and heterogeneous likely because of the relatively recent onset of its popularity. While a few authors have demonstrated the potential strength and hypertrophy benefits of perioperative BFR, future investigations with standardized outcomes, long-term follow-up, and more robust sample sizes are required to draw more definitive conclusions.

OBJECTIVETo evaluate the ability of trained nonphysician retinal imagers to perform diabetic retinopathy (DR) evaluation at the time of ultrawide field retinal (UWF) imaging in a teleophthalmology program. RESEARCH DESIGN AND METHODSClinic patients with diabetes received Joslin Vision Network protocol retinal imaging as part of their standard medical care. Retinal imagers evaluated UWF images for referable DR at the time of image capture. Training of the imagers included 4 h of standardized didactic lectures and 12 h of guided image review. Real-time evaluations were compared with standard masked gradings performed at a centralized reading center. RESULTSA total of 3,978 eyes of 1,989 consecutive patients were imaged and evaluated. By reading center evaluation, 3,769 eyes (94.7%) were gradable for DR, 1,376 (36.5%) had DR, and 580 (15.3%) had referable DR. Compared with the reading center, real-time image evaluation had a sensitivity and specificity for identifying more than minimal DR of 0.95 (95% CI 0.94-0.97) and 0.84 (0.82-0.85), respectively, and 0.99 (0.97-1.00) and 0.76 (0.75-0.78), respectively, for detecting referable DR. Only three patients with referable DR were not identified by imager evaluation. CONCLUSIONSPoint-of-care evaluation of UWF images by nonphysician imagers following standardized acquisition and evaluation protocols within an established teleophthalmology program had good sensitivity and specificity for detection of DR and for identification of referable retinal disease. With immediate image evaluation, <0.1% of patients with referable DR would be missed, reading center image grading burden would be reduced by 60%, and patient feedback would be expedited.Patients with diabetes require lifelong ophthalmic care that generally includes an annual retinal evaluation (1). Given the rapidly growing population affected by diabetes, a 20-year estimate of .2.7 million eyes worldwide will need to be evaluated each day just to fulfill these needs (2). This enormous task is unlikely to be accomplished by the current approaches of diabetes eye care programs. Despite more than one decade of research, no real-time, fully automated retinal image analysis system is currently in active clinical use (2). Until such capability exists, other approaches to speed efficiency of current programs without sacrificing accuracy are urgently needed.