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Sample records for acl reconstruction methods

  1. ACL reconstruction

    MedlinePlus

    ... This increases the chance you may have a meniscus tear. ACL reconstruction may be used for these ... When other ligaments are also injured When your meniscus is torn Before surgery, talk to your health ...

  2. ACL reconstruction - discharge

    MedlinePlus

    Anterior cruciate ligament reconstruction - discharge; ACL reconstruction - discharge ... had surgery to reconstruct your anterior cruciate ligament (ACL). The surgeon drilled holes in the bones of ...

  3. ACL Reconstruction

    MedlinePlus

    ... of the major ligaments in your knee. ACL injuries most commonly occur during sports that involve sudden stops and changes in direction — such as basketball, soccer, football, tennis, downhill skiing, volleyball and gymnastics. In ...

  4. Mycotic Infection post ACL Reconstruction

    PubMed Central

    Costa-Paz, Matias; Ayerza, Miguel; Carbo, Lisandro; Sanchez, Marisa; Yacuzzi, Carlos; Muscolo, Luis

    2017-01-01

    Objectives: There are several studies in literature of septic arthritis after the ACL arthroscopic reconstruction related to bacterial germs. However, fungi infection is likely infrequent generating a massive bone loss with a catastrophic result. The purpose of this study was to describe preventive measures to decrease the mycotic infection after ACL reconstruction. Methods: Since 2005, we have diagnosed and treated 22 immunocompetent patients who underwent a surgery of an ACL lesion in other institutions in the country. Form these cases, we analyzed 19 which developed mycotic infection and an oncologic debridement was performed to control the pathology. In this series, we considered the initial surgery, the number of toilettes performed until their referral, magnitude of bone loss and final outcome. There were 5 other patients who consulted for mucormycosis, who finally were treated in other hospitals. Results: Epidemiology of mucormycosis is not clear. The exact cause is unknown due to heterogeneous data, different places and surgeons, facilities and type of surgical instruments in this series. In spite of not knowing the cause of the infection, several alternatives were evaluated in a non systematic way. Most of them related to the surgery room, sterilization place of the surgical tools, use of sterilizing liquids, cleanliness of lumen and cannulated bits. Instruments used during surgery were also evaluated: fields, shaver blades, drill types, ACL reconstruction fixation method. It is doubtful if the type of graft to reconstruct the ACL had any relation with infections. Among ideal preventive measures, the following are described: Surgery room with temperature and humidity control. Not using sterilizing liquids. Optimal preparation of surgical tools with adequate cleanliness of lumen and cannulated bits performed by adequate personnel. Sterilize in the same place where the surgery will be performed. Use of adequate instruments. The use of the central third of

  5. Transphyseal ACL Reconstruction in Skeletally Immature Patients

    PubMed Central

    Cruz, Aristides I.; Lakomkin, Nikita; Fabricant, Peter D.; Lawrence, J. Todd R.

    2016-01-01

    Background: Most studies examining the safety and efficacy of transphyseal anterior cruciate ligament (ACL) reconstruction for skeletally immature patients utilize transtibial drilling. Independent femoral tunnel drilling may impart a different pattern of distal femoral physeal involvement. Purpose: To radiographically assess differences in distal femoral physeal disruption between transtibial and independent femoral tunnel drilling. We hypothesized that more oblique tunnels associated with independent drilling involve a significantly larger area of physeal disruption compared with vertically oriented tunnels. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We analyzed skeletally immature patients aged between 10 and 15 years who underwent transphyseal ACL reconstruction utilizing an independent femoral tunnel drilling technique between January 1, 2008, and March 31, 2011. These patients were matched with a transtibial technique cohort based on age and sex. Radiographic measurements were recorded from preoperative magnetic resonance imaging and postoperative radiographs. Results: Ten patients in each group were analyzed. There were significant differences between independent drilling and transtibial drilling cohorts in the estimated area of physeal disruption (1.64 vs 0.74 cm2; P < .001), femoral tunnel angles (32.1° vs 72.8°; P < .001), and medial/lateral location of the femoral tunnel (24.2 vs 36.1 mm from lateral cortex; P = .001), respectively. There was a significant inverse correlation between femoral tunnel angle and estimated area of distal femoral physeal disruption (r = –0.8255, P = .003). Conclusion: Femoral tunnels created with an independent tunnel drilling technique disrupt a larger area of the distal femoral physis and create more eccentric tunnels compared with a transtibial technique. Clinical Relevance: As most studies noting the safety of transphyseal ACL reconstruction have utilized a central, vertical femoral tunnel

  6. PROPRIOCEPTION, BODY BALANCE AND FUNCTIONALITY IN INDIVIDUALS WITH ACL RECONSTRUCTION

    PubMed Central

    Furlanetto, Tássia Silveira; Peyré-Tartaruga, Leonardo Alexandre; do Pinho, Alexandre Severo; Bernardes, Emanuele da Silva; Zaro, Milton Antonio

    2016-01-01

    Objective : To evaluate and compare proprioception, body balance and knee functionality of individuals with or without unilateral anterior cruciate ligament (ACL) reconstruction. Methods : Forty individuals were divided in two groups: Experimental group, 20 individuals with ACL reconstruction at six months postoperative, and control group, 20 individuals with no history of lower limb pathologies. In the experimental group, we assessed lower limbs with reconstructed ACL and contralateral limb; in the control group the dominant and the non-dominant lower limbs were assessed. All subjects were submitted to joint position sense test to evaluate proprioception, postural control measure in single-limb, and step up and down (SUD) test for functional assessment. Results : There were no deficits in proprioception and postural control. In the SUD test, a 5% decrease in lift up force was found in reconstructed ACL lower limbs, however, a statistically not significant difference. The impact and step down force during the course of test were 30% greater in anatomic ACL than in control lower limbs. Conclusion : The individuals with ACL reconstruction at six months postoperative did not show changes in proprioception and postural control, but showed motor control changes, influencing knee functionality. Level of Evidence IV, Prognostic Studies. PMID:26981038

  7. Isokinetic Testing in Evaluation Rehabilitation Outcome After ACL Reconstruction

    PubMed Central

    Cvjetkovic, Dragana Dragicevic; Bijeljac, Sinisa; Palija, Stanislav; Talic, Goran; Radulovic, Tatjana Nozica; Kosanovic, Milkica Glogovac; Manojlovic, Slavko

    2015-01-01

    Introduction: Numerous rehab protocols have been used in rehabilitation after ACL reconstruction. Isokinetic testing is an objective way to evaluate dynamic stability of the knee joint that estimates the quality of rehabilitation outcome after ACL reconstruction. Our investigation goal was to show importance of isokinetic testing in evaluation thigh muscle strength in patients which underwent ACL reconstruction and rehabilitation protocol. Subjects and methods: In prospective study, we evaluated 40 subjects which were divided into two groups. Experimental group consisted of 20 recreational males which underwent ACL reconstruction with hamstring tendon and rehabilitation protocol 6 months before isokinetic testing. Control group (20 subjects) consisted of healthy recreational males. In all subjects knee muscle testing was performed on a Biodex System 4 Pro isokinetic dynamo-meter et velocities of 60°/s and 180°/s. We followed average peak torque to body weight (PT/BW) and classic H/Q ratio. In statistical analysis Student’s T test was used. Results: There were statistically significant differences between groups in all evaluated parameters except of the mean value of PT/BW of the quadriceps et velocity of 60°/s (p>0.05). Conclusion: Isokinetic testing of dynamic stabilizers of the knee is need in diagnostic and treatment thigh muscle imbalance. We believe that isokinetic testing is an objective parameter for return to sport activities after ACL reconstruction. PMID:25870471

  8. ACL reconstruction in children: a transphyseal technique.

    PubMed

    Lemaitre, G; Salle de Chou, E; Pineau, V; Rochcongar, G; Delforge, S; Bronfen, C; Haumont, T; Hulet, C

    2014-06-01

    The annual incidence of ACL tears is increasing steadily in pediatric patients. Chronic anterior instability causes meniscal lesions at a frequency that increases significantly with the injury-to-surgery interval. Conservative therapy, simple suturing, and isolated extra-articular tendon reconstruction are associated with high failure rates. Intra-articular arthroscopy-assisted tendon reconstruction is a good treatment method, although several different techniques have been described. We used a transphyseal technique with a hamstring tendon graft to treat 14 knees in 13 patients with a mean age of 13 years and 7 months. Mean injury-to-surgery interval was 6 months. Strict compliance with technical rules is required when using this technique. Bone tunnel diameter must not exceed 8 mm. Bone tunnels must be as vertical and central as possible. The fixation material must not bridge the physis (at the femur, cortical fixation; and at the tibia, fixation using a resorbable screw no longer than 25 mm combined with a staple). Meniscal lesions were present in half the knees and meniscal preservation considered mandatory. Conservative treatment of concomitant lesions was performed routinely. After a mean follow-up of 15 months, no recurrent tears or revision procedures for meniscectomy had been recorded. The IKDC grade was A or B in 93% of knees. The mean subjective IKDC score was 83.3 and the Lysholm score was in the excellent or good range in 93% of knees. Of the 14 knees, 2 exhibited signs suggesting femoral epiphysiodesis, with 4° of valgus deformity compared to the contra-lateral knee and no clinical consequences. Transphyseal reconstruction with open physes conducted in strict compliance with technical rules can be performed to control the instability and preserve the menisci. Nevertheless, this technique carries a risk of epiphysiodesis, chiefly at the femur.

  9. Risk Factors and Predictors of Subsequent ACL Injury in either Knee after ACL Reconstruction: Prospective Analysis of 2488 Primary ACL Reconstructions from the MOON Cohort

    PubMed Central

    Kaeding, Christopher C.; Pedroza, Angela D.; Reinke, Emily K.; Huston, Laura J.; Spindler, Kurt P.

    2015-01-01

    Background Anterior cruciate ligament (ACL) re-injury results in worse outcomes and increases risk of post-traumatic osteoarthritis. Objectives To identify the risk factors for both ipsilateral and contralateral ACL tears after primary ACL reconstruction (ACLR). Study Design Cohort study; Level of evidence, 3. Methods Data from the Multicenter Orthopaedic Outcomes Network (MOON), a prospective longitudinal cohort, were used to identify risk factors for ACL retear. Subjects with primary ACLR, no history of contralateral knee surgery, and a minimum of 2-year follow-up data were included. Age, sex, Marx activity score, graft type, lateral meniscus tear, medial meniscus tear, sport played at index injury, and surgical facility were evaluated to determine their contribution to both ipsilateral retear and contralateral ACL tear. Results A total of 2683 subjects with average age of 27 ± 11 years (1498 men; 56%) met all study inclusion/exclusion criteria. Overall there were 4.4% ipsilateral graft tears and 3.5% contralateral ACL tears. The odds of ipsilateral retear were 5.2 times greater for an allograft (p<0.01) compared with a bone-patellar tendon-bone (BTB) autograft; the odds of retear were not significantly different between BTB autograft and hamstring autograft (p=0.12). The odds of an ipsilateral ACL retear decreased by 0.09 for every yearly increase in age (p<0.01) and increased by 0.11 for every increased point on the Marx score (p< 0.01). The odds were not significantly influenced by sex, smoking status, sport played, medial or lateral meniscus tear, or consortium site (p>0.05). The odds of a contralateral ACL tear decreased by 0.04 for every yearly increase in age (p=0.04) and increased by 0.12 for every increased point on the Marx score (p<0.01); these odds were not significantly different between sex, smoking status, sport played, graft type, medial meniscal tear, and lateral meniscal tear (p>0.05). Conclusions Younger age, higher activity level, and

  10. ACL reconstruction with BPTB autograft and irradiated fresh frozen allograft*

    PubMed Central

    Sun, Kang; Tian, Shao-qi; Zhang, Ji-hua; Xia, Chang-suo; Zhang, Cai-long; Yu, Teng-bo

    2009-01-01

    Objective: To analyze the clinical outcomes of arthroscopic anterior cruciate ligament (ACL) reconstruction with irradiated bone-patellar tendon-bone (BPTB) allograft compared with non-irradiated allograft and autograft. Methods: All BPTB allografts were obtained from a single tissue bank and the irradiated allografts were sterilized with 2.5 mrad of irradiation prior to distribution. A total of 68 patients undergoing arthroscopic ACL reconstruction were prospectively randomized consecutively into one of the two groups (autograft and irradiated allograft groups). The same surgical technique was used in all operations done by the same senior surgeon. Before surgery and at the average of 31 months of follow-up (ranging from 24 to 47 months), patients were evaluated by the same observer according to objective and subjective clinical evaluations. Results: Of these patients, 65 (autograft 33, irradiated allograft 32) were available for full evaluation. When the irradiated allograft group was compared to the autograft group at the 31-month follow-up by the Lachman test, the anterior drawer test (ADT), the pivot shift test, and KT-2000 arthrometer test, statistically significant differences were found. Most importantly, 87.8% of patients in the autograft group and just only 31.3% in the irradiated allograft group had a side-to-side difference of less than 3 mm according to KT-2000. The failure rate of the ACL reconstruction with irradiated allograft (34.4%) was higher than that with autograft (6.1%). The anterior and rotational stabilities decreased significantly in the irradiated allograft group. According to the overall International Knee Documentation Committee (IKDC), functional and subjective evaluations, and activity level testing, no statistically significant differences were found between the two groups. Besides, patients in the irradiated allograft group had a shorter operation time and a longer duration of postoperative fever. When the patients had a fever, the

  11. Outcome of ACL Reconstruction for Chronic ACL Injury in Knees without the Posterior Horn of the Medial Meniscus: Comparison with ACL Reconstructed Knees with An Intact Medial Meniscus

    PubMed Central

    Syam, Kevin; Chouhan, Devendra K.; Dhillon, Mandeep Singh

    2017-01-01

    Purpose Cadaveric studies have shown that deficiency of the posterior horn of the medial meniscus (PHMM) increases strain on the anterior cruciate ligament (ACL) graft. However, its influence on the clinical and radiological outcome after ACL reconstruction is less discussed and hence evaluated in this study. Materials and Methods This study included 77 cases of ACL reconstruction with a minimum 18-month follow-up. Of the 77 cases, 41 patients with intact menisci were compared clinically and radiologically with 36 patients with an injury to the PHMM that required various grades of meniscectomy. The knees were evaluated using subjective International Knee Documentation Committee (IKDC) score and Orthopadische Arbeitsgruppe Knie (OAK) score. Results Cases with intact menisci showed better stability (p=0.004) at an average of 44.51 months after surgery. No significant differences were noted in the overall OAK score, subjective IKDC score, and functional OAK score (p=0.082, p=0.526, and p=0.363, respectively). The incidence of radiological osteoarthrosis was significantly higher in the posterior horn deficient knees (p=0.022). Conclusions The tendency toward relatively higher objective instability and increased incidence of osteoarthrosis in the group with absent posterior horn reinforces its importance as a secondary stabiliser of the knee. PMID:28231647

  12. ACL reconstruction in a teenage athlete with fibular hemimelia.

    PubMed

    Mascarenhas, Randy; Simon, David; Forsythe, Brian; Harner, Christopher D

    2014-03-01

    Fibular hemimelia exists as a rare cause of ACL insufficiency. This case report concerns the diagnosis and treatment of anterior cruciate ligament insufficiency in a teenage football player with fibular hemimelia. While ACL reconstruction has been described to allow activities of daily living in this patient population, this is the first report in the literature of anterior cruciate ligament reconstruction in an athlete with fibular hemimelia. We believe that ACL reconstruction is a viable and beneficial treatment option in the care of a symptomatic patient with congenital absence of the ACL and can allow athletes with this condition to return not only to their previous functional level, but also to their previous level of play.

  13. Knee extension torque variability after exercise in ACL reconstructed knees.

    PubMed

    Goetschius, John; Kuenze, Christopher M; Hart, Joseph M

    2015-08-01

    The purpose of this study was to compare knee extension torque variability in patients with ACL reconstructed knees before and after exercise. Thirty two patients with an ACL reconstructed knee (ACL-R group) and 32 healthy controls (control group) completed measures of maximal isometric knee extension torque (90° flexion) at baseline and following a 30-min exercise protocol (post-exercise). Exercise included 30-min of repeated cycles of inclined treadmill walking and hopping tasks. Dependent variables were the coefficient of variation (CV) and raw-change in CV (ΔCV): CV = (torque standard deviation/torque mean x 100), ΔCV = (post-exercise - baseline). There was a group-by-time interaction (p = 0.03) on CV. The ACL-R group demonstrated greater CV than the control group at baseline (ACL-R = 1.07 ± 0.55, control = 0.79 ± 0.42, p = 0.03) and post-exercise (ACL-R = 1.60 ± 0.91, control = 0.94 ± 0.41, p = 0.001). ΔCV was greater (p = 0.03) in the ACL-R group (0.52 ± 0.82) than control group (0.15 ± 0.46). CV significantly increased from baseline to post-exercise (p = 0.001) in the ACL-R group, while the control group did not (p = 0.06). The ACL-R group demonstrated greater knee extension torque variability than the control group. Exercise increased torque variability more in the ACL-R group than control group.

  14. Physeal Disruption During ACL Reconstruction in Skeletally Immature Patients

    PubMed Central

    Cruz, Aristides Ignacio; Lakomkin, Nikita; Fabricant, Peter D.; Lawrence, John Todd R.

    2016-01-01

    Objectives: The purpose of this study was to radiographically assess differences in distal femoral physeal disruption between transtibial and independent femoral tunnel drilling techniques following ACL reconstruction in skeletally immature patients. Methods: A retrospective, matched comparative cohort study was performed of skeletally immature patients who underwent transphyseal ACL reconstruction between January 1, 2008 and March 31, 2011. All skeletally immature patients between ten and fifteen years old who underwent independent femoral tunnel drilling and had adequate baseline and post-operative radiographs were analyzed. These patients were matched with a transtibial technique cohort based on age and sex. Demographic characteristics and peri-operative metrics were collected. Radiographic measurements were recorded from pre-operative MRI and post-operative plain radiographs. Results: Twenty patients were analyzed. Between groups, there were significant differences between independent tunnel drilling and transtibial tunnel drilling in the estimated area of physeal disruption (1.64 cm2 vs. 0.74 cm2, P<0.001), femoral (32.1º vs. 72.8º, P<0.001) and tibial (50.1º vs. 60.5º, P=0.003) tunnel angles, medial/lateral location of the femoral tunnel (24.2 mm vs. 36.1 mm from lateral cortex, P=0.001), and distance from the lateral aspect of the distal femoral physis and the femoral tunnel exit (4.7 mm vs. 26.7 mm from the perichondrial ring, P<0.001), respectively. All patients who underwent femoral tunnel drilling at an angle of less than 25º from the transverse axis experienced a greater than 6% disruption of physeal area. There was a significant inverse correlation between femoral tunnel angle and estimated area of femoral physeal involvement (r=-0.8255, P=0.003). Conclusion: With femoral tunnel drilling techniques that create more oblique tunnels, the area of distal femoral physeal damage is larger, more eccentric and closer to the perichondrial ring. Since most

  15. Partial ACL tears: anatomic reconstruction versus nonanatomic augmentation surgery.

    PubMed

    Buda, Roberto; Ruffilli, Alberto; Parma, Alessandro; Pagliazzi, Gherardo; Luciani, Deianira; Ramponi, Laura; Castagnini, Francesco; Giannini, Sandro

    2013-09-01

    Treatment of partial anterior cruciate ligament (ACL) tears requires ACL remnant preservation. The goal of this study was to compare the outcome of anatomic reconstruction of the torn bundle with nonanatomic augmentation using the over-the-top femoral route. Fifty-two athletes (mean age, 23.3 years) with partial ACL lesions underwent anatomic reconstruction (n=26) or nonanatomic augmentation (n=26). Intraoperative damage of the healthy bundle that required a standard ACL reconstruction occurred in 2 patients in the anatomic reconstruction group. International Knee Documentation Committee (IKDC) score, Tegner score, and arthrometer evaluation were used pre-operatively and at follow-up for up to 5 years postoperatively. One failure occurred in the anatomic reconstruction group. Mean IKDC subjective score at follow-up was 88.2 ± 5.7 in the anatomic reconstruction group and 90.2 ± 4.7 in the nonanatomic augmentation group. According to the IKDC objective score at final follow-up, 96% of knees in the nonanatomic augmentation group were normal vs 87.5% in the anatomic reconstruction group. No significative differences were observed between the 2 groups at final follow-up. Anteromedial bundle reconstruction showed significantly lower IKDC subjective and objective scores and higher residual instability values as evaluated with the arthrometer compared with posterolateral bundle reconstruction (P=.017). The surgical treatment of ACL partial tears is demanding. Adapted portals, perfect control of the tunnel drilling process, and intercondylar space management are required in anatomic reconstruction. The nonanatomic augmentation technique is simpler, providing excellent durable results over time with a lower complication rate. Anteromedial bundle reconstruction is associated with a poorer outcome, especially when performed with anatomic reconstruction.

  16. KNEE SYNERGISM DURING GAIT REMAIN ALTERED ONE YEAR AFTER ACL RECONSTRUCTION

    PubMed Central

    LEPORACE, GUSTAVO; METSAVAHT, LEONARDO; PEREIRA, GLAUBER RIBEIRO; OLIVEIRA, LISZT PALMEIRA DE; CRESPO, BERNARDO; BATISTA, LUIZ ALBERTO

    2016-01-01

    ABSTRACT Objective: To compare the activation of the vastus lateralis (VL) and biceps femoris (BF) muscles during gait, as well VL/BF muscular co-contraction (MCC) between healthy (CG) and anterior cruciate ligament reconstructed (ACL-R) subjects. Methods: Nineteen subjects, ten controls and nine ACL-R patients had a VL and BF electromyogram (EMG) captured to calculate the MCC ratio. A Principal Component (PC) Analysis was applied to reduce the dimensionality effect of each of the MCC, VL and BF curves for both healthy and ACL reconstructed groups. The PC scores were used to calculate the standard distance (SD). SD values were employed in order to compare each dependent variable (MCC, VL and BF) between the two groups using unpaired t-test. Results: ACL-R group presented a lower VL activation at the beginning and at the end of the gait cycle, as compared to the control group. However, no difference was found for BF or VL/BF MCC. Conclusion: The gait analysis of ACL reconstructed patients demonstrated a persistent deficit in VL activation when compared to the control group, even one year after surgery. Level of Evidence III. Case Control Study PMID:27217814

  17. Growth disturbances without growth arrest after ACL reconstruction in children.

    PubMed

    Chotel, Franck; Henry, Julien; Seil, Romain; Chouteau, Julien; Moyen, Bernard; Bérard, Jérôme

    2010-11-01

    Growth arrest is a major concern after ACL reconstruction in children. It usually occurs in patients near to closure of the growth plates. Growth disturbances without growth arrest are also possible and more vicious; the authors analyse the mechanism of two patients with growth disturbance due to overgrowth following ACL reconstruction. One was a symmetrical overgrowth process with 15 mm limb length discrepancy treated with percutaneous epiphysiodesis. Full correction at the time of skeletal maturity was achieved. The second patient developed an asymmetrical overgrowth with progressive tibial valgus deformity. This mechanism was similar to a posttraumatic tibial valgus deformity. After nonoperative treatment, a spontaneous correction of the deformity was noticed. Both children were young (7 and 10 years old) at the time of ACL reconstruction with an autologous iliotibial band graft. The clinical relevance of overgrowth disturbance is usually limited when compared to growth arrest but could require a second surgical procedure as reported in this study. Parents must be informed that even in experienced hands, and despite the use of a physeal sparing technique, this specific risk of growth disturbance is still present.

  18. From open to arthroscopic anatomical ACL-reconstructions: the long way round. A statement paper.

    PubMed

    Arnold, Markus P; Friederich, Niklaus F; Müller, Werner; Hirschmann, Michael T

    2013-07-01

    The single-incision anterior cruciate ligament (ACL) reconstruction evidently has its shortcomings. In an attempt to improve the biomechanical but also the biological state of the knees after an ACL-reconstruction, double, even triple-bundle reconstructions have been popularised recently. As a positive side effect, details concerning ACL-insertion anatomy were brought back into the focus. In our opinion it would be more straight forward and logical to replace the non-anatomical single-incision technique with a more anatomic single-bundle ACL-reconstruction technique.

  19. Return to sports after ACL reconstruction: a new functional test protocol

    PubMed Central

    Bisciotti, Gian Nicola; Quaglia, Alessandro; Belli, Andrea; Carimati, Giulia; Volpi, Piero

    2016-01-01

    Summary Background In literature, there are lack of studies proposing clear and rationally designed test battery to be performed after an ACL reconstruction. Methods From 2006 to 2015, 80 football players were subjected, after ACL reconstruction, to a newly conceived test battery analyzing: Isometric and isokinetic force production The different phases during the jump The correct control of the landing phase after jump The control of valgus during landing after jump and cutting movements. Results The isokinetic and isometric test do not show any significant relationship with the another test. The laboratory test as well the field test showed them a significant correlation. Conclusions The results showed that a normal force production during the laboratory does not guarantee an equally satisfactory production of force during the field test. Study design Case series (Level III). PMID:28217573

  20. Utilization of Modified NFL Combine Testing to Identify Functional Deficits in Athletes Following ACL Reconstruction

    PubMed Central

    MYER, GREGORY D.; SCHMITT, LAURA C.; BRENT, JENSEN L.; FORD, KEVIN R.; BARBER FOSS, KIM D.; SCHERER, BRADLEY J.; HEIDT, ROBERT S.; DIVINE, JON G.; HEWETT, TIMOTHY E.

    2012-01-01

    STUDY DESIGN Case control. OBJECTIVES To use modified NFL Combine testing methodology to test for functional deficits in athletes following anterior cruciate ligament (ACL) reconstruction following return to sport. BACKGROUND There is a need to develop objective, performance-based, on-field assessment methods designed to identify potential lower extremity performance deficits and related impairments in this population. METHODS Eighteen patients (mean ± SD age, 16.9 ± 2.1 years; height, 170.0 ± 8.7 cm; body mass, 71.9 ± 21.8 kg) who returned to their sport within a year following ACL reconstruction (95% CI: 7.8 to 11.9 months from surgery) participated (ACLR group). These individuals were asked to bring 1 or 2 teammates to serve as control participants, who were matched for sex, sport, and age (n = 20; mean ± SD age, 16.9 ± 1.1 years; height, 169.7 ± 8.4 cm; body mass, 70.1 ± 20.7 kg). Functional performance was tested using the broad jump, vertical jump, modified long shuttle, modified pro shuttle, modified agility T-test, timed hop, triple hop, single hop, and crossover hop tests. A 1-way multivariate analysis of variance (MANOVA) was used to evaluate group differences for dependent performance variables. RESULTS The functional performance measurements of skills requiring bilateral involvement of both lower extremities showed no group differences between the ACLR and control groups (P>.05). An overall group difference (P = .006) was observed for the combined limb symmetry index (LSI) measures. However, the modified double-limb performance tasks (long shuttle, modified agility T-test, and pro shuttle) were not, independently, sufficiently sensitive to detect limb deficits in individuals with ACL reconstruction. Conversely, the LSI on the distance measures of the single-limb performance tasks all provided moderate to large effect sizes to differentiate between the ACLR and control groups, as the individuals who had ACL reconstruction demonstrated involved

  1. Correlation between fixation systems elasticity and bone tunnel widening after ACL reconstruction

    PubMed Central

    Giorgio, Nicola; Moretti, Lorenzo; Pignataro, Paolo; Carrozzo, Massimiliano; Vicenti, Giovanni; Moretti, Biagio

    2016-01-01

    Summary Background Femoral and tibial tunnel widening (TW) after ACL reconstruction is a phenomenon increasing talk in the literature. It is underlying biological and mechanical causes. Objective The aim of this study was to evaluate the relationship between bone tunnel enlargement and two different ACL fixation systems. Patients and Methods 40 patient underwent ACL reconstruction with hamstring; randomly divided into group A with 20 patients treated with stiff systems (femoral Rigidfix and tibial interference screw), and into group B, with 20 patients treated with morel elastic system (femoral and tibial Tight-rope). Evaluated postoperatively with knee MRI at 40 days, 3 months, 6 months to measure bone tunnel diameters widening. Results At 40 days tunnel widening between two groups shows no statistically difference. At 3 months postoperatively, femoral bone tunnel widening amounted on average to 1.84 mm in middle of tunnel and 1 mm at the mouth in joint in group A, and respectively 3.2 mm and 2.5 mm in group B (p<0.05). Tibial tunnel widening was 1.24 mm at the mouth in joint and 1.3 mm in middle in group A and respectively 2.26 mm and 2.43 mm in group B (p<0.05). At 6 months femoral tunnel widening amounted on average to 2.45 mm in middle and 1.35 mm at the mouth in joint in group A and respectively 3.5 mm and 2.7 mm in group B (p<0.01). Tibial tunnel widening amounted on average to 1.27 at mouth in joint and 1 mm in middle of tunnel in group A and respectively 2.6 mm and 2.3 mm in group B (p<0.01). Conclusions This study results suggest elastic fixation system increases bone tunnel enlargement after ACL reconstruction with hamstring without correlation with worse clinical performance. Level of evidence IV. PMID:28217568

  2. ACL reconstruction: in vivo measurement of patellar tendon graft elongation.

    PubMed

    Berruto, M; Howe, J G; Beynnon, B D; Johnson, R J; Nichols, C E; Pope, M H

    1991-06-01

    The implantation of a free autogenous patellar tendon graft is the surgical technique that currently offers the best results in anterior cruciate ligament reconstruction. However, numerous aspects regarding both technique and postoperative rehabilitation can still be improved. The aim of this study was to measure the elongation of the patellar tendon in vivo in the operating room after reconstructive surgery, subjecting the knee to normal strain such as passive mobilization or anterior displacement of the tibia. Three volunteers were studied. Our results were different from those reported in a previous study conducted in vivo on a normal anterior cruciate ligament (ACL). In spite of the isometric position of the tendon, passive mobilization provoked a progressive increase in the elongation of the graft within each cycle of flexion-extension and between one cycle and the next. This also occurred during the Lachman test. These findings suggest that the graft undergoes a process of tensile adjustment when it is first put under strain. Continued elongation once this process appears stabilized raises doubts as to the reliability of isometric measuring devices.

  3. Degeneration in ACL Injured Knees with and without Reconstruction in Relation to Muscle Size and Fat Content—Data from the Osteoarthritis Initiative

    PubMed Central

    Baum, Thomas; Nevitt, Michael C.; Nardo, Lorenzo; Gersing, Alexandra S.; Lane, Nancy E.; McCulloch, Charles E.; Rummeny, Ernst J.; Link, Thomas M.

    2016-01-01

    Background Anterior cruciate ligaments (ACL) injuries represent a major risk factor for early osteoarthritis (OA). Purpose To evaluate the prevalence and 4-year progression of knee OA measured with 3T MR-imaging in individuals with ruptured, reconstructed or normal ACL and to assess the impact of thigh muscle characteristics. Methods A total of 54 knees (23/54 male, 31/54 female) were recruited from the Osteoarthritis Initiative (OAI). At baseline, 15/54 subjects had prevalent ACL ruptures and 15/54 subjects had prevalent ACL reconstruction (24/54 normal ACL). Western Ontario and McMasters Universities Arthritis Index (WOMAC) scores, Physical Activity Scores of the Elderly (PASE) and thigh muscle characteristics including strength, fat infiltration (Goutallier score) and thigh muscle cross-sectional area (CSA) MR measurements were obtained at baseline. Whole-organ MR-imaging Scores (WORMS) were obtained at baseline and at a 4-year follow-up time-point. Multivariate regression models, adjusting for covariates (age, gender, body mass index), were used for statistical analysis. Results At baseline, subjects with prevalent ACL ruptures had worse WORMS total scores (mean±SEM, 44.1±3.5) than subjects with ACL reconstruction (30.8±4.0; P = 0.015) and worse than subjects with normal ACL (21.3±3.0; P<0.001). Cartilage scores were worse in both femorotibial compartments in ACL injured knees than in knees with normal ACL (P<0.05). Knees with ACL reconstruction showed an increased degeneration of the medial meniscus (P = 0.036), cartilage degeneration at the medial femoral condyle (P = 0.011). In a multivariate regression model, including both ACL groups and total muscle characteristics as influence parameters, high thigh muscle CSA, high muscle/ fat ratio and low Goutallier scores were associated with less degenerative changes at the knee, independent of ACL status. Knees with ACL reconstruction showed an increased progression of cartilage degeneration at the medial tibia

  4. Pretibial Cyst Formation after ACL Reconstruction. A series of 14 cases with different etiologies

    PubMed Central

    Zicaro, Juan Pablo; Ranalletta, Maximiliano; Avila, Christian Garcia; Yacuzzi, Carlos; Costa-Paz, Matias

    2017-01-01

    Objectives: Among complications following an ACL reconstruction, the formation of a pre-tibial cyst in the site of the tibial tunnel is rare and might happen even years after surgery. The purpose of this study was to analyze 14 patients with pretibial cyst after ACL reconstruction. Methods: We retrospectively evaluated patients between 2008 and 2016. The inclusion criteria were patients who underwent an ACL reconstruction, and developed an extra-articular cyst at the tibial tunnel level. For recurrence evaluation, patients with less than one-year follow-up were excluded. A pre and postoperative clinical and radiological evaluation was performed. We analyzed the graft selection and surgical technique for ACL reconstruction, the time between primary surgery and onset of symptoms, and the clinical presentation. A pre and postoperative radiological evaluation was performed for every patient. Surgical technique for cyst excision, histological analysis and culture results were also analyzed. The recurrence rate was evaluated at final follow-up. Results: Nine patients were male, with an average age of 38 years. The average follow-up was of 35 months. All ACL reconstructions were performed using hamstrings graft and a trans-tibial technique. Tibial fixation was performed with a biodegradable screw in 9 patients, three of them associated with the use of a staple. In four patients hamstrings tibial insertion was left in situ with an open stripper and fixed in the tibia using non-absorbable Ethibond 2 sutures. The average time between primary ACL surgery and onset of the cyst was 29 months. All patients presented a palpable tumor at proximal tibia and a stable knee. The cyst size varied between 1 and 3 cm. In all cases, Rx and MRI showed a widening of the tibial tunnel, though no articular communication could be confirmed. The arthroscopic evaluation revealed no graft loosening. All cysts were approached through the previous tibial incision and staples or screws where removed

  5. Comparison of grafts for anatomical reconstruction of the ACL: patellar versus semitendinosus/gracilis☆

    PubMed Central

    Bitun, Patrícia Barros; Miranda, Carlos Roberto; Escudero, Ricardo Boso; Araf, Marcelo; de Souza, Daphnis Gonçalves

    2015-01-01

    Objective To compare the functional results from surgical treatment for anatomical reconstruction of the anterior cruciate ligament (ACL) with a single band, using two types of autologous grafts. Methods Twenty-seven patients who underwent anatomical reconstruction of the ACL by means of the Chambat technique were evaluated prospectively. They were divided into two groups: A, with 14 patients, using grafts from flexor tendons; and B, with 13 patients, using grafts from the patellar tendon. In both groups, fixation was performed using an absorbable interference screw. Results Based on the Lysholm score, group A presented a mean score of 71.6 in the first month, while B presented 75. At the end of the sixth month, both groups presented 96.6. Evaluation of the total IKDC showed that in the first month, the majority of the patients, both in group A (85.7%) and in group B (76.9%), presented a knee assessment that was close to normal. In the sixth month, 92.9% of group A had normal presentations, and 100% of group B. Conclusion According to the Lysholm functional evaluation and the IKDC subjective assessment, there was no statistically significant difference in the results between the groups, and the results were better in the sixth month. PMID:26229896

  6. Hop tests correlate with IKDC and KOOS at minimum of 2 years after primary ACL reconstruction

    PubMed Central

    Reinke, Emily K.; Lorring, Dawn; Jones, Morgan H.; Schmitz, Leah; Flanigan, David C.; An, Angel Qi; Quiram, Amanda R.; Preston, Emily; Martin, Michael; Schroeder, Bettina; Parker, Richard D.; Kaeding, Christopher C.; Borzi, Lynn; Pedroza, Angela; Huston, Laura J.; Harrell, Frank E.; Dunn, Warren R.

    2012-01-01

    Purpose The hypothesis of this study was that single-legged horizontal hop test ratios would correlate with IKDC, KOOS, and Marx activity level scores in patients 2 years after primary ACL reconstruction. Methods Individual patient-reported outcome tools and hop test ratios on 69 ACL reconstructed patients were compared using correlations and multivariable modeling. Correlations between specific questions on the IKDC and KOOS concerning the ability to jump and hop ratios were also performed. Results The triple-hop ratio was moderately but significantly correlated with the IKDC, KOOS Sports and Recreation subscale, and the KOOS Knee Related Quality of Life subscale, as well as with the specific questions related to jumping. Similar but weaker relationship patterns were found for the single-hop ratio and timed hop. No significant correlations were found for the Marx activity level or crossover-hop ratio. Multivariable modeling showed almost no significant additional contribution to predictability of the IKDC or KOOS subscores by gender, BMI, or the number of faults on either leg. Conclusions The triple-hop test is most significantly correlated with patient-reported outcome scores. Multivariable modeling indicates that less than a quarter of the variability in outcome scores can be explained by hop test results. This indicates that neither test can serve as a direct proxy for the other; however, assessment of patient physical function by either direct report using validated outcome tools or by the hop test will provide relatively comparable data. Level of evidence II. PMID:21445595

  7. Correlation between body mass index and quadrupled hamstring tendon autograft size in ACL reconstruction

    PubMed Central

    ATBAŞI, ZAFER; ERÇIN, ERSIN; ERDEM, YUSUF; EMRE, TULUHAN YUNUS; ATILLA, HALIS ATIL; PARLAK, ADEM

    2016-01-01

    Purpose the aim of this study was to assess the relationship of patient weight, height and body mass index (BMI) with the size of the quadrupled hamstring tendon used in anterior cruciate ligament (ACL) reconstruction. Methods from patient records, we retrospectively assessed the weight, height, BMI and graft sizes of 126 patients who underwent ACL reconstruction using a quadrupled hamstring tendon autograft between January 2010 and January 2013 at our institution. The data obtained from perioperative measurements were studied using correlation analysis. Results statistically significant relationships were found between patient height and graft diameter (p = 0.033, r = 0.19) and between patient weight and graft diameter (p < 0.0001, r = 0.33). No statistically significant relationships were found between graft diameter and BMI or between graft length and patient height, weight and BMI (p > 0.05). Conclusions patient height and weight were found to be related to quadrupled hamstring graft diameter in our patient population. BMI was not related to the quadrupled hamstring graft size. The exact size of the graft cannot be predicted preoperatively on the basis of these variables. Level of evidence Level IV, retrospective case series. PMID:28217655

  8. Frontal plane knee mechanics and medial cartilage MR relaxation times in individuals with ACL reconstruction : A pilot study

    PubMed Central

    Kumar, Deepak; Kothari, Abbas; Souza, Richard B.; Wu, Samuel; Ma, C. Benjamin; Li, Xiaojuan

    2014-01-01

    Background The objective of this pilot study was to evaluate cartilage T1ρ and T2 relaxation times and knee mechanics during walking and drop-landing for individuals with anterior cruciate ligament reconstruction (ACL-R). Methods Nine patients (6 men and 3 women, Age 35.8±5.4 years, BMI 23.5±2.5 kg/m2) participated 1.5±0.8 years after single-bundle two-tunnel ACL reconstruction. Peak knee adduction moment (KAM), flexion moment (KFM), extension moment (KEM), and peak varus were calculated from kinematic and kinetic data obtained during walking and drop-landing tasks. T1ρ and T2 times were calculated for medial femur (MF), and medial tibia (MT) cartilage and compared between subjects with low KAM and high KAM. Biomechanical variables were compared between limbs. Results The high KAM group had higher T1ρ for MT (p = 0.01), central MT (p = 0.05), posterior MF (p = 0.04), posterior MT (p = 0.01); and higher T2 for MT (p = 0.02), MF (p = 0.05) posterior MF (p = 0.002) and posterior MT (p = 0.01). During walking, ACL-R knees had greater flexion at initial contact (p =0.04), and lower KEM (p = 0.02). During drop-landing, the ACL-R knees had lower KAM (p = 0.03) and KFM (p = 0.002). Conclusion Patients with ACL-R who have higher KAM during walking had elevated MR relaxation times in the medial knee compartments. These data suggest that those individuals who have undergone ACL-R and have higher frontal plane loading, may be at a greater risk of knee osteoarthritis. PMID:24993277

  9. Asymmetrical lower extremity loading after ACL reconstruction: more than meets the eye.

    PubMed

    Chmielewski, Terese L

    2011-06-01

    Sports fans know that movement patterns are important for athletic performance. Similarly, clinicians know that addressing abnormal movement patterns after an anterior cruciate ligament (ACL) reconstruction is important for a successful return to sport. The kinematic (motion) component of movement patterns is more easily observed than the kinetic (forces) component, thus more commonly addressed in ACL reconstruction rehabilitation. Ignoring the kinetic component, though, could impede a successful return to sport. Asymmetrical lower extremity loading has been reported in a variety of activities following ACL reconstruction, and may contribute to both short- and long-term consequences. It is important that clinicians become aware of the potential for asymmetrical lower extremity loading to affect patient outcomes and for researchers to enlarge the body of knowledge.

  10. Anterior cruciate ligament reconstruction using cryopreserved irradiated bone-ACL-bone-allograft transplants.

    PubMed

    Goertzen, M J; Clahsen, H; Schulitz, K P

    1994-01-01

    Bone-ACL-bone allograft transplantation has been investigated as a potential solution to reconstruction of the anterior cruciate ligament (ACL). To minimize disease transmission (e.g. the acquired immuno deficiency syndrome), bony and collagenous tissues should be sterilized. Recent animal studies indicate that gamma irradiation and ethylene oxide sterilization result in diminished histological and biomechanical properties. The purpose of the present study was biomechanical and histological determination of the fate of deep-frozen gamma-irradiated (2.5 Mrad) canine bone-ACL-bone allografts with argon gas protection. Particular attention was paid to collagenous and neuroanatomical morphology 3, 6 and 12 months after implantation, by comparison to a non-irradiated control group. Sixty skeletally mature foxhounds were operated on in this study, divided up in two groups of 30 dogs each. In group A animals the ACL was replaced by a deep-frozen (-80 degrees C) bone-ACL-bone LAD-augmented allograft subjected to 2.5 Mrad gamma irradiation with argon gas protection. The animals in group B received an LAD-augmented ACL-allograft transplant without gamma irradiation. All knees from both groups were evaluated 3, 6 and 12 months after implantation in regard to biomechanical properties, collagen morphology and routine histology (haematoxylin and eosin stain, polarization microscopy), neuroanatomical morphology (silver and gold chloride stain) and microvasculature (modified Spalteholz technique). The irradiated ACL allografts withstood a maximum load that was 63.8% (718.3 N) of the maximum load of normal ACLs after 12 months. By contrast, the non-irradiated allografts failed at 69.1% (780.1 N) of the maximum load of normal control ACLs.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Gait Patterns Differ Between ACL-Reconstructed Athletes Who Pass Return-to-Sport Criteria and Those Who Fail

    PubMed Central

    Di Stasi, Stephanie L.; Logerstedt, David; Gardinier, Emily S.; Snyder-Mackler, Lynn

    2013-01-01

    Background The current standard of practice for an athlete to return to sport after anterior cruciate ligament (ACL) reconstruction is varied. Attempt to return to activity is typically advised 6 months after surgery, but functional performance deficits and gait abnormalities are often still evident and may have important implications on future function. Hypothesis When comparing the involved and uninvolved limbs, patients who failed return-to-sport (RTS) criteria would demonstrate (1) smaller peak knee angles, extensor moments, and peak power absorption at the knee of the involved limb and (2) larger peak hip angles, extensor moments, and peak power generation of the involved limb. Study Design Controlled laboratory study. Methods A total of 42 patients completed functional and biomechanical gait assessment 6 months after ACL reconstruction. Functional testing involved an isometric quadriceps strength test, 4 single-legged hop tests, and 2 self-report questionnaires. Three-dimensional motion analysis was used to measure sagittal plane kinematics and kinetics of the hip and knee. A mixed-model analysis of variance and post hoc t tests were used to compare the limb symmetry of those who passed and those who did not pass RTS criteria. Minimal clinically important differences were calculated from healthy gait data and used to further define meaningful limb asymmetries. Results Twenty of the 42 (48%) patients passed RTS criteria 6 months after ACL reconstruction. Patients who did not pass the criteria demonstrated statistically significant differences between limbs on all kinematic and kinetic variables at the knee (P ≤ .027). Clinically meaningful asymmetries at the hip were also identified in this group. Only kinetic asymmetries at the knee were identified in the patients who passed RTS criteria. Conclusion Athletes who demonstrate superior functional performance 6 months after ACL reconstruction may have fewer abnormal and asymmetrical gait behaviors than their

  12. Modified Transtibial versus Anteromedial Portal Technique in Single Bundle ACL Reconstruction

    PubMed Central

    Salinas, Emiliano Alvarez; Etcheto, Horacio Rivarola; Blanchod, Cristian Collazo; Escobar, Gonzalo; Zordan, Jesuan; Autorino, Carlos María

    2017-01-01

    Objectives: The aim of this study is to determine whether it is possible to achieves a similar anatomical placement of the femoral tunnel with a modified transtibial ACL single bundle reconstruction tecnique compared to anteromedial transportal technique. Results were evaluated by tomographic comparisons between patients from both groups. Methods: 36 patients (36 knees) who were candidates for an ACL single bundle reconstruction with patellar bone graft were included in the study. Patients were randomly allocated using a computerized sequence into two groups. 18 patients were assigned each group (modified transtibial vs AM transportal technique). Surgery was performed by the same surgical team in both groups. Femoral tunnel quadrant placement, oblicuity in the coronal and sagittal planes and diameter of the femoral tunnel were assesed tomographically blinded by two observers and statistical comparison between groups was realized. Results: Average distance measured from posterior edge of the condyle to the femoral tunnel ( measured as a proportion respect to the T line) was similar in both groups ( Group I : 32.7 % +- 5.1% ; Group 2: 32.4 % +-4.4% , p = 0.85). Average distance measured from the Blumensaat line to the femoral tunnel (measured as a proportion respect to the H line) was similar in both groups ( Group I: 28.5% 4.49 % Group II , 31.5% of 4.83% p = 0.06). Average angulation values of the femoral tunnel in the coronal plane were lower in Group I than in Group II (Group I = 34.8 ° range 32.7 ° - 38.6 ° and 41.2 ° range Group II 36.7 ° - 43.1 ° P = 0.0016 ). Average angulation values of the femoral tunnel in the sagittal plane were similar in both groups (Group I 40.2 ° range 38.4 ° - 43.4 ° ; Group II 38 1 ° range 36.6 ° - 40.2 ° p = 0.17).. The average diameter of the femoral tunnel was significantly higher in group I than in Group II (Group I 11 mm 0.84 mm and 10.2 mm Group II 0.65mm p = 0.007) . Conclusion: The modified transtibial technique

  13. The use of platelets to affect functional healing of an anterior cruciate ligament (ACL) autograft in a caprine ACL reconstruction model.

    PubMed

    Spindler, Kurt P; Murray, Martha M; Carey, James L; Zurakowski, David; Fleming, Braden C

    2009-05-01

    Many anterior cruciate ligament (ACL) reconstructions have increased laxity postoperatively. We hypothesized that enhancing an ACL graft with a collagen-platelet composite (CPC) would improve knee laxity and graft structural properties. We also hypothesized the platelet concentration in the CPC would affect these parameters. Twelve goats underwent ACL reconstruction with autologous patellar tendon graft. In six goats, a collagen-platelet composite was placed around the graft (CPC group). In the remaining six goats, the collagen scaffold only was used (COLL group). Three goats were excluded due to complications. After 6 weeks in vivo, anterior-posterior (AP) laxity and tensile properties of the ACL reconstructed knees were measured and normalized against the contralateral intact knee. At a knee flexion angle of 30 degrees, the average increase in AP laxity was 40% less in the CPC group than the COLL group (p = 0.045). At 60 degrees, the AP laxity was 30% less in the CPC group, a difference that was close to statistical significance (p = 0.080). No differences were found between treatment groups with respect to the structural properties (p > 0.30). However, there were significant correlations between serum platelet concentration and AP laxity (R2 = 0.643; p = 0.009), maximum load (R2 = 0.691; p = 0.006), and graft stiffness (R2 = 0.840; p < 0.001). In conclusion, use of a CPC to enhance healing of an allograft ACL reconstruction inversely correlated with early sagittal plane laxity and the systemic platelet count was highly predictive of ACL reconstruction graft strength and stiffness at 6 weeks. These findings emphasize the importance of further research on delineating the effect of platelets in treating of ACL injuries.

  14. The effect of platelet concentrates on graft maturation and graft-bone interface healing in ACL reconstruction in human patients

    PubMed Central

    Vavken, Patrick; Sadoghi, Patrick; Murray, Martha M

    2011-01-01

    Purpose To systematically review the current evidence for effects of platelet concentrates on (1) graft maturation and (2) graft-bone interface healing in ACL reconstruction in human, controlled trials, and for ensuing differences in clinical outcomes. Methods A systematic search of PubMed, CINAHL, EMBASE, CCTR and CDSR was performed for controlled trials of human ACL reconstruction with and without platelet concentrates. Data validity was assessed and data were collected on graft maturation, graft-bone interface healing and clinical outcome. Results Eight studies met the inclusion criteria. Seven studies reported on graft maturation with significantly better outcomes in the platelet groups in four, and large differences in means in two (underpowered) studies. Five studies report on tunnel healing, but four found no difference between groups. Three studies assessed clinical outcome but found no differences, regardless whether they had shown a benefical (1/3) or no effect (2/3) of platelets on graft and tunnel healing. Conclusion The current best evidence suggests that the addition of platelet concentrates to ACL reconstruction may have a beneficial effect on graft maturation and could improve it by 20–30% on average, but with substantial variability. The most likely mode of action is that treatment with platelets accelerates graft repopulation and remodeling, and this interpretation is supported by the existing data and biologically plausible. However, the current evidence also shows only a very limited influence of platelet concentrates on graft-bone interface healing and no significant difference in clinical outcomes. Clinical Relevance This systematic review collected evidence that the use of platelet concentrates may be a safe and inexpensive way to optimize graft maturation after ACL reconstruction, but there is no evidence for improved graft-bone interface healing or a significant difference in clinical outcomes. Level of Evidence Level IV, systematic

  15. In vivo analysis of the pivot shift phenomenon during computer navigated ACL reconstruction.

    PubMed

    Lane, Clayton G; Warren, Russell F; Stanford, Fatima C; Kendoff, Daniel; Pearle, Andrew D

    2008-05-01

    ACL insufficiency can be documented clinically with the pivot shift maneuver, but the specific pathologic kinematics of the pivot shift is difficult to quantify. Navigation provides an opportunity to analyze in vivo the motions that comprise the pivot shift and the kinematic changes that are inherent after ACL reconstruction. We hypothesized that tibial rotation, anterior tibial translation (ATT), acceleration of posterior translation (APT) and the newly described angle of P, quantified during navigated pivot shift examination, correlate with clinical grading of the pivot shift phenomena. Navigation data from 12 patients who underwent navigated ACL surgery were retrospectively reviewed. A characteristic P-shaped track of motion is recorded by the navigation software during the pivot-shift examination. The "angle of P" was developed as a means characterizing this track of motion and was measured in all cases. The tibial rotation, maximum anterior tibial translation and acceleration of posterior translation during the pivot shift were also measured. The charts of these patients were reviewed to obtain information on the clinical grading of the pivot-shift before and after ACL reconstruction. Spearman correlation analysis was then used to identify significant correlations between clinical grade of the pivot shift and the angle of p measured with computer navigation. After reconstruction, the clinical grade of the pivot shift was zero in all patients. The tibial rotation, maximum ATT, APT and the angle of p also decreased. On analysis of 24 EUAs, 12 before reconstruction and 12 after, there was excellent and significant correlation between the clinical grade of pivot shift examination and the angle of P (R2 = 0.97, p < 0.001). Only good correlation was noted between the clinical pivot shift and the rotation (R2 = 0.77, p < 0.0001), maximum ATT (R2 = 0.87, p < 0.0001) and APT (R2 = 0.81, p < 0.0001). There was a stepwise increase of 6-7 mm of translation and 5-6 degrees

  16. Bioresorbable scaffolds for anterior cruciate ligament reconstruction: do we need an off-the-shelf ACL substitute?

    PubMed

    Richmond, John C; Weitzel, Paul P

    2010-03-01

    Currently available anterior cruciate ligament (ACL) graft sources, autograft and allograft, present potential problems that a natural biomaterial ACL graft might be able to solve. Earlier efforts in the development of synthetic ACL grafts were less than optimal, and those devices have largely been abandoned. We can learn from these past failures, and potentially develop a bioresorbable scaffold for ACL reconstruction, which will provide immediate stability, promote and direct tissue in growth, and degrade at an appropriate rate, without harmful wear debris. We have developed a modified silk scaffold, which is currently being evaluated in humans in a pilot study.

  17. Knee functional recovery and limb-to-limb symmetry restoration after anterior cruciate ligament (ACL) rupture and ACL reconstruction

    NASA Astrophysics Data System (ADS)

    Nawasreh, Zakariya Hussein

    Anterior cruciate ligament (ACL) rupture is a common sport injury of young athletes who participate in jumping, cutting, and pivoting activities. Although ACL reconstruction (ACLR) surgery has the goal of enabling athletes to return to preinjury activity levels, treatment results often fall short of this goal. The outcomes after ACLR are variable and less than optimal with low rate of return to preinjury activity level and high risk for second ACL injury. Factors related to the knee functional limitations, strength deficits, and limb-to-limb movement asymmetry may be associated with poor outcomes after ACLR. Additionally, the criteria that are used to determine a patient's readiness to return to the preinjury activity level are undefined which may also be associated with poor outcomes after ACLR. The clinical decision-making to clear patients' for safe and successful return to high physical activities should be based on a universal comprehensive set of objective criteria that ensure normal knee function and limb-to-limb symmetry. A battery of return to activity criteria (RTAC) that emphases normal knee function and limb-to-limb movement symmetry has been constituted to better ensure safe and successful return to preinjury activity level. Yet, only variables related to patients' demographics, concomitant injuries, and treatment measures have been used to predict return to preinjury activity levels after ACLR. However, the ability of RTAC variables that ensure normal knee function and limb movement symmetry to predict the return to participate in the same preinjury activity level after ACLR has not been investigated. In light of this background, the first aim of the present study was to compare functional knee performance-based and patient-reported measures of those who PASS and who FAIL on RTAC at 6 months (6-M) following ACLR with those at 12 months (12-M) and 24 months (24-M) following ACLR and to determine how performance-based and patient-reported measures

  18. Persistent Biomechanical Alterations After ACL Reconstruction Are Associated With Early Cartilage Matrix Changes Detected by Quantitative MR

    PubMed Central

    Amano, Keiko; Pedoia, Valentina; Su, Favian; Souza, Richard B.; Li, Xiaojuan; Ma, C. Benjamin

    2016-01-01

    Background: The effectiveness of anterior cruciate ligament (ACL) reconstruction in preventing early osteoarthritis is debated. Restoring the original biomechanics may potentially prevent degeneration, but apparent pathomechanisms have yet to be described. Newer quantitative magnetic resonance (qMR) imaging techniques, specifically T1ρ and T2, offer novel, noninvasive methods of visualizing and quantifying early cartilage degeneration. Purpose: To determine the tibiofemoral biomechanical alterations before and after ACL reconstruction using magnetic resonance imaging (MRI) and to evaluate the association between biomechanics and cartilage degeneration using T1ρ and T2. Study Design: Cohort study; Level of evidence, 2. Methods: Knee MRIs of 51 individuals (mean age, 29.5 ± 8.4 years) with unilateral ACL injuries were obtained prior to surgery; 19 control subjects (mean age, 30.7 ± 5.3 years) were also scanned. Follow-up MRIs were obtained at 6 months and 1 year. Tibial position (TP), internal tibial rotation (ITR), and T1ρ and T2 were calculated using an in-house Matlab program. Student t tests, repeated measures, and regression models were used to compare differences between injured and uninjured sides, observe longitudinal changes, and evaluate correlations between TP, ITR, and T1ρ and T2. Results: TP was significantly more anterior on the injured side at all time points (P < .001). ITR was significantly increased on the injured side prior to surgery (P = .033). At 1 year, a more anterior TP was associated with elevated T1ρ (P = .002) and T2 (P = .026) in the posterolateral tibia and with decreased T2 in the central lateral femur (P = .048); ITR was associated with increased T1ρ in the posteromedial femur (P = .009). ITR at 6 months was associated with increased T1ρ at 1 year in the posteromedial tibia (P = .029). Conclusion: Persistent biomechanical alterations after ACL reconstruction are related to significant changes in cartilage T1ρ and T2 at 1 year

  19. Sex-specific gait adaptations prior to and up to six months after ACL reconstruction

    PubMed Central

    Stasi, Stephanie L. Di; Hartigan, Erin H.; Snyder-Mackler, Lynn

    2015-01-01

    STUDY DESIGN Controlled longitudinal laboratory study. OBJECTIVES Compare sagittal plane gait mechanics of men and women before and up to 6 months after anterior cruciate ligament reconstruction (ACLR). BACKGROUND Aberrant gait patterns are ubiquitous after anterior cruciate ligament (ACL) rupture and persist after ACLR despite skilled physical therapy. Sex influences post-operative function and second ACL injury risk, but its influence on gait adaptations after injury have not been investigated. METHODS Sagittal plane knee and hip joint excursions during midstance and internal knee and hip extension moments at peak knee flexion were collected on 12 women and 27 men using 3-dimensional gait analysis before (Screen) and after pre-operative physical therapy (Pre-sx), and 6 months after ACLR (6mo). Repeated measures analysis of variance models were used to determine whether limb asymmetries changed differently over time in men and women. RESULTS Significant time x limb x sex interactions were identified for hip and knee excursions and internal knee extension moments (P≤.007). Both sexes demonstrated smaller knee excursions on the involved compared to the uninvolved knee at each time point (P≤.007), but only women demonstrated a decrease in the involved knee excursion from pre-sx to 6mo (P=.03). Women also demonstrated smaller hip excursions (P<.001) and internal knee extension moments (P=.005) on the involved limb compared to the uninvolved limb at 6mo. Men demonstrated smaller hip excursions and knee moments on the involved limb compared to the uninvolved limb (main effects, P<.001). CONCLUSION The persistence of limb asymmetries in men and women 6 months after ACLR indicates that current rehabilitation efforts are inadequate for some individuals following ACLR. PMID:25627155

  20. Which one Enhances Muscular Performance in ACL Reconstructed Subjects

    PubMed Central

    Harput, Gulcan; Ulusoy, Burak; Atay, Ahmet Ozgur; Baltacı, Gul

    2014-01-01

    Objectives: The aim of this study was to investigate the effects of functional knee brace and kinesiotaping on muscular performance in anterior cruciate ligament reconstructed subjects who reached return to sport phase of the rehabilitation. Methods: Twenty (17 males, 3 females, Age: 24.7±7.1 years, Body weight: 74.4±12.0 kg, Height: 177.9±6.5 cm, BMI: 23.9±3.6 kg/m2) subjects who underwent anterior cruciate ligament reconstruction by using hamstring tendon auto graft were included in this study. When the subjects reached the return to sports phase of rehabilitation which was 6th months after surgery, knee muscle strength, jump performance and balance tests were performed 3 times: bare, with knee brace and with kinesio taping. The order of the tests were randomized to eliminate the effects of fatigue and motor learning. Quadriceps and hamstring muscle strength was measured on an isokinetic dynamometer at 180 °/s and 60°/s angular velocities. Vertical Jump (VJ) and One Leg Hop Tests (OLHT) were used to assess jump performance. Star Excursion Balance Test (SEBT) with anterior, posteromedial and posterolateral reach distance was used to assess the dynamic balance. When all tests were performed, the subjects were asked under which test condition they felt more confident. Repeated measures of ANOVA was used to analyze the difference among three test conditions (bare, kinesiotaping, knee brace). Bonferroni post hoc test was used for pairwise comparison. Results: SEBT posteromedial (PM)and posterolateral (PL) reach distances were found significantly different among three test conditions(PM: F(2,38)=3.42,p=0.04), PL: F(2,38)=4.37,p=0.02). Kinesiotaping increased posteromedial reach distance (p=0.03). On the other hand, brace decreased posterolateral reach distance (p=0.04). VJ and OLHT performance were also found significantly different between three test conditions (VJ: F (2,38)=3.44,p=0.04, OLHT: (F(2,38)=4.04,p=0.02). Kinesio taping increased one leg hop distance

  1. Giant Cell Tumor within the Proximal Tibia after ACL Reconstruction.

    PubMed

    Takahashi, Takashi; MacCormick, Lauren; Ellermann, Jutta; Clohisy, Denis; Marette, Shelly

    2016-01-01

    26-year-old female with prior anterior cruciate ligament reconstruction developed an enlarging lytic bone lesion around the tibial screw with sequential imaging over the course of one year demonstrating progression of this finding, which was confirmed histologically to be a giant cell tumor of bone. The lesion originated around the postoperative bed, making the diagnosis challenging during the early course of the presentation. The case demonstrates giant cell tumor which originated in the metaphysis and subsequently grew to involve the epiphysis; therefore, early course of the disease not involving the epiphysis should not exclude this diagnosis.

  2. Giant Cell Tumor within the Proximal Tibia after ACL Reconstruction

    PubMed Central

    Takahashi, Takashi; MacCormick, Lauren; Ellermann, Jutta; Clohisy, Denis; Marette, Shelly

    2016-01-01

    26-year-old female with prior anterior cruciate ligament reconstruction developed an enlarging lytic bone lesion around the tibial screw with sequential imaging over the course of one year demonstrating progression of this finding, which was confirmed histologically to be a giant cell tumor of bone. The lesion originated around the postoperative bed, making the diagnosis challenging during the early course of the presentation. The case demonstrates giant cell tumor which originated in the metaphysis and subsequently grew to involve the epiphysis; therefore, early course of the disease not involving the epiphysis should not exclude this diagnosis. PMID:26981302

  3. Anterior cruciate ligament- and hamstring tendon-derived cells: in vitro differential properties of cells involved in ACL reconstruction.

    PubMed

    Ghebes, Corina Adriana; Kelder, Cindy; Schot, Thomas; Renard, Auke J; Pakvis, Dean F M; Fernandes, Hugo; Saris, Daniel B

    2015-03-11

    Anterior cruciate ligament (ACL) reconstruction involves the replacement of the torn ligament with a new graft, often a hamstring tendon (HT). Described as similar, the ACL and HT have intrinsic differences related to their distinct anatomical locations. From a cellular perspective, identifying these differences represents a step forward in the search for new cues that enhance recovery after the reconstruction. The purpose of this study was to characterize the phenotype and multilineage potential of ACL- and HT-derived cells. ACL- and HT-derived cells were isolated from tissue harvest from patients undergoing total knee arthroplasty (TKA) or ACL reconstruction. In total, three ACL and three HT donors were investigated. Cell morphology, self-renewal potential (CFU-F), surface marker profiling, expression of tendon/ligament-related markers (PCR) and multilineage potential were analysed for both cell types; both had fibroblast-like morphology and low self-renewal potential. No differences in the expression of tendon/ligament-related genes or a selected set of surface markers were observed between the two cell types. However, differences in their multilineage potential were observed: while ACL-derived cells showed a high potential to differentiate into chondrocytes and adipocytes, but not osteoblasts, HT-derived cells showed poor potential to form adipocytes, chondrocytes and osteoblasts. Our results demonstrated that HT-derived cells have low multilineage potential compared to ACL-derived cells, further highlighting the need for extrinsic signals to fully restore the function of the ACL upon reconstruction. Copyright © 2015 John Wiley & Sons, Ltd.

  4. Assessing 3D tunnel position in ACL reconstruction using a novel single image 3D-2D registration

    NASA Astrophysics Data System (ADS)

    Kang, X.; Yau, W. P.; Otake, Y.; Cheung, P. Y. S.; Hu, Y.; Taylor, R. H.

    2012-02-01

    The routinely used procedure for evaluating tunnel positions following anterior cruciate ligament (ACL) reconstructions based on standard X-ray images is known to pose difficulties in terms of obtaining accurate measures, especially in providing three-dimensional tunnel positions. This is largely due to the variability in individual knee joint pose relative to X-ray plates. Accurate results were reported using postoperative CT. However, its extensive usage in clinical routine is hampered by its major requirement of having CT scans of individual patients, which is not available for most ACL reconstructions. These difficulties are addressed through the proposed method, which aligns a knee model to X-ray images using our novel single-image 3D-2D registration method and then estimates the 3D tunnel position. In the proposed method, the alignment is achieved by using a novel contour-based 3D-2D registration method wherein image contours are treated as a set of oriented points. However, instead of using some form of orientation weighting function and multiplying it with a distance function, we formulate the 3D-2D registration as a probability density estimation using a mixture of von Mises-Fisher-Gaussian (vMFG) distributions and solve it through an expectation maximization (EM) algorithm. Compared with the ground-truth established from postoperative CT, our registration method in an experiment using a plastic phantom showed accurate results with errors of (-0.43°+/-1.19°, 0.45°+/-2.17°, 0.23°+/-1.05°) and (0.03+/-0.55, -0.03+/-0.54, -2.73+/-1.64) mm. As for the entry point of the ACL tunnel, one of the key measurements, it was obtained with high accuracy of 0.53+/-0.30 mm distance errors.

  5. PATIENT-SPECIFIC AND SURGERY-SPECIFIC FACTORS THAT AFFECT RETURN TO SPORT AFTER ACL RECONSTRUCTION

    PubMed Central

    Lynch, Andrew; Rabuck, Stephen; Lynch, Brittany; Davin, Sarah; Irrgang, James

    2016-01-01

    Context Anterior cruciate ligament (ACL) reconstruction is frequently performed to allow individuals to return to their pre-injury levels of sports participation, however, return to pre-injury level of sport is poor and re-injury rates are unacceptably high. Re-injury is likely associated with the timeframe and guidelines for return to sport (RTS). It is imperative for clinicians to recognize risk factors for re-injury and to ensure that modifiable risk factors are addressed prior to RTS. The purpose of this commentary is to summarize the current literature on the outcomes following return to sport after ACL reconstruction and to outline the biologic and patient-specific factors that should be considered when counseling an athlete on their progression through rehabilitation. Evidence Acquisition A comprehensive literature search was performed to identify RTS criteria and RTS rates after ACL reconstruction with consideration paid to graft healing, anatomic reconstruction, and risk factors for re-injury and revision. Results were screened for relevant original research articles and review articles, from which results were summarized. Study Design Clinical Review of the Literature Results Variable RTS rates are presented in the literature due to variable definitions of RTS ranging from a high threshold (return to competition) to low threshold (physician clearance for return to play). Re-injury and contralateral injury rates are greater than the risk for primary ACL injury, which may be related to insufficient RTS guidelines based on time from surgery, which do not allow for proper healing or resolution of post-operative impairments and elimination of risk factors associated with both primary and secondary ACL injuries. Conclusions RTS rates to pre-injury level of activity after ACLR are poor and the risk for graft injury or contralateral injury requiring an additional surgery is substantial. Resolving impairments while eliminating movement patterns associated with

  6. THE ROLE AND IMPLEMENTATION OF ECCENTRIC TRAINING IN ATHLETIC REHABILITATION: TENDINOPATHY, HAMSTRING STRAINS, AND ACL RECONSTRUCTION

    PubMed Central

    Reiman, Michael

    2011-01-01

    The benefits and proposed physiological mechanisms of eccentric exercise have previously been elucidated and eccentric exercise has been used for well over seventy years. Traditionally, eccentric exercise has been used as a regular component of strength training. However, in recent years, eccentric exercise has been used in rehabilitation to manage a host of conditions. Of note, there is evidence in the literature supporting eccentric exercise for the rehabilitation of tendinopathies, muscle strains, and in anterior cruciate ligament (ACL) rehabilitation. The purpose of this Clinical Commentary is to discuss the physiologic mechanism of eccentric exercise as well as to review the literature regarding the utilization of eccentric training during rehabilitation. A secondary purpose of this commentary is to provide the reader with a framework for the implementation of eccentric training during rehabilitation of tendinopathies, muscle strains, and after ACL reconstruction. PMID:21655455

  7. Effect of Calcium Phosphate–Hybridized Tendon Graft in Anatomic Single-Bundle ACL Reconstruction in Goats

    PubMed Central

    Mutsuzaki, Hirotaka; Fujie, Hiromichi; Nakajima, Hiromi; Fukagawa, Makoto; Nomura, Shunsuke; Sakane, Masataka

    2016-01-01

    Background: We previously developed a novel technique using an alternate soaking process that improves tendon-bone healing by hybridizing the tendon graft with calcium phosphate (CaP). However, the effects of the CaP-hybridized tendon graft on anatomic single-bundle anterior cruciate ligament (ACL) reconstruction remain unclear. Purpose: To determine the effects of CaP-hybridized tendon grafts compared with untreated tendon grafts 6 months after anatomic single-bundle ACL reconstruction using a goat model. Study Design: Controlled laboratory study. Methods: Animals were divided into a CaP group (n = 5 goats) and a control group (n = 5 goats), and we analyzed (1) knee kinematics and in situ forces under applied anterior tibial loads of 50 N and internal tibial torque of 2.0 N·m in the grafts at full extension and at 60° and 90° of knee flexion, (2) the mean percentage of bone tunnel enlargement using computed tomography (CT), and (3) the histology of the tendon-bone interface. Results: The in situ forces under applied anterior tibial loads of 50 N at 60° and 90° of knee flexion in the CaP group were greater than those in the control group (P < .05). The red safranin-O–stained area, indicating glycosaminoglycans in the cartilage layers at the joint aperture sites of the anterior femoral and posterior tibial bone tunnel, was greater in the CaP group than that in the control group (P < .05). The lengths of the nonbonding gap area between the anterior femoral and posterior tibial bone tunnels in the control group were greater than those in the CaP group (P < .05). No significant difference could be detected in the mean percentage of bone tunnel enlargement between the 2 groups. Conclusion: The CaP-hybridized tendon graft enhanced tendon-bone healing at the joint aperture site in both anterior femoral and posterior tibial tunnels 6 months after anatomic single-bundle ACL reconstruction in goats. The in situ forces under applied anterior tibial loads at greater

  8. Do Newer-Generation Bioabsorbable Screws Become Incorporated into Bone at Two Years After ACL Reconstruction with Patellar Tendon Graft?

    PubMed Central

    Cox, Charles L.; Spindler, Kurt P.; Leonard, James P.; Morris, Brent J.; Dunn, Warren R.; Reinke, Emily K.

    2014-01-01

    Background: Bioabsorbable interference screws are used frequently for graft fixation in ACL (anterior cruciate ligament) reconstruction. The resorption properties of many available screws that are marketed as bioabsorbable are not well defined. The CALAXO (Smith & Nephew Endoscopy) and MILAGRO (DePuy Synthes) bioabsorbable screws contain polymers of poly(lactic-co-glycolic acid) (PLGA) plus additives to encourage osseointegration over time. The purpose of this study was to evaluate radiographic and magnetic resonance imaging (MRI) properties and compare patient-reported outcomes at a minimum of two years of follow-up after ACL reconstruction using CALAXO or MILAGRO bioabsorbable interference screws. Methods: A cohort of patients who underwent ACL reconstruction in which the fixation used was either CALAXO or MILAGRO screws returned for repeat radiographs for evaluation of tunnel widening, repeat MRI for evaluation of graft integrity and screw breakdown, and completion of the pain and symptom items of the KOOS (Knee injury and Osteoarthritis Outcome Score) questionnaire. Results: At a mean of three years (range, 2.5 to 4.0 years) after surgery, thirty-one patients with sixty-two CALAXO screws and thirty-six patients with seventy-two MILAGRO screws returned for repeat evaluation. Two blinded, independent reviewers found no significant differences between the two screw types when comparing radiographs for tibial or femoral tunnel widening or MRIs for graft integrity, tibial and femoral foreign body reactions, or femoral screw degradation. Both reviewers found a significant difference between the two screw types when comparing tibial screw degradation properties (p < 0.01). All analyzed CALAXO screws were rated as partially intact or degraded; the MILAGRO screws were more likely to be rated as intact. No significant differences were noted between the two screw types when comparing the two KOOS subscales. Conclusions: CALAXO screws in the tibial tunnel were more likely

  9. THE CLINICAL UTILITY OF FUNCTIONAL PERFORMANCE TESTS WITHIN ONE-YEAR POST-ACL RECONSTRUCTION: A SYSTEMATIC REVIEW

    PubMed Central

    Narducci, Elizabeth; Waltz, Amanda; Gorski, Katheryn; Leppla, Lucas

    2011-01-01

    Introduction: A tear of the anterior cruciate ligament (ACL) represents a significant injury for an athlete that requires substantial time away from sport, and significant rehabilitation after reconstruction. The physical therapist is responsible to determine when a patient is capable of tolerating the physical demands of daily activities and to attempt to prevent re-injury. Physical or functional performance tests (FPTs) are one mechanism used to evaluate the athlete's physical skills and capabilities prior to returning to sports participation. The purpose of this systematic review is to critically examine the clinical utility of functional performance tests used with patients less than or equal to one year post ACL reconstruction. Methods: A systematic review of the relevant literature was performed using PRISMA guidelines. A total of twelve studies were included for analysis. Results: Two independent blinded reviewers then analyzed and rated the final included articles (n=12) utilizing the Newcastle-Ottawa Scale (NOS). Percent overall agreement between raters for the NOS was 88% with a fixed-marginal kappa (κ) of 0.80. Of the 12 included articles, the FPTs were utilized as an outcome measure within the study design (41.7%) or studied as a measure of function (58.3%). Among those studies that used FPTs as a “measure of function” 71.4% studied a battery of FPTs, while 28.6% studied a single test. None of the studies utilized FPTs as a measure to determine readiness to return to sport. Discussion: FPTs are being utilized with patients, less than or equal to one year post ACL reconstruction, either as an assessment of functional performance or as an outcome measure. No studies identified a FPT or test battery that has construct or predictive validity for “return to sport” in athletic population one-year post-ACL reconstruction. The identification of the critical elements within the return to sport construct may allow lower extremity performance tests to be

  10. KNEE KINEMATICS FOLLOWING ACL RECONSTRUCTION IN FEMALES; THE EFFECT OF VISION ON PERFORMANCE DURING A CUTTING TASK

    PubMed Central

    Di Fabio, Richard P.

    2011-01-01

    Purpose/Background: Specific movement patterns have been identified as influential in ACL injury; however several key kinematic variables that might be predictive of future performance have not been fully investigated. The purpose of this research was to: 1) determine if subjects with ACL reconstruction display different displacement, velocity, and time to peak ground reaction force (GRF) during cutting activities than healthy subjects, 2) observe if subjects with visual disruption display differences in these variables, and 3) determine if visual disruption alters these variables in subjects with ACL reconstruction relative to healthy subjects. Methods: Seventeen healthy female subjects and 17 female subjects with unilateral ACL reconstruction (ACLR) performed 40 trials of a cutting movement during which knee position was measured via a 3D electromagnetic system. Visual conditions were randomized to disrupt vision for 1 second as the subject began the cutting movement, or allow full vision for movement duration. Independent variables were lead/push off leg (ACLR limb or healthy non-dominant limb) and vision (disrupted or full). 2-way ANOVAs were utilized to determine differences between knee kinematics using dependent variables of displacement (m), absolute velocity (m/sec), and time to reach peak GRF (% of cut). Results: Knee displacement was significantly less for ACLR (.76±.11; .75±.16) than non-dominant (.85±.08; .87±.12). Knee velocity was significantly slower for ACLR (.81±.14; .84±.16) than non-dominant (.92±.11; .97±.14). A significant interaction was noted for displacement and average velocity (p<.05). Time to reach peak GRF was significantly longer for ACLR (79.41±2.28) than non-dominant (76.65±4.41). Conclusions: Subjects with ACLR displayed less knee displacement, slower velocity, and an increased time to reach peak GRF relative to healthy subjects' non-dominant knee. Visual disruption appeared to have some effect on movement, as noted by

  11. Rehabilitation of Patients Following Autogenic Bone-Patellar Tendon-Bone ACL Reconstruction: A 20-Year Perspective

    PubMed Central

    De Carlo, Mark S.; McDivitt, Ryan

    2006-01-01

    Rehabilitation of patients following anterior cruciate ligament (ACL) reconstruction has undergone remarkable improvements over the past two decades. During this time, ACL research has been at the forefront of many orthopaedic and sports physical therapy clinics. With over 20 years of ACL rehabilitation experience (senior author) and prior collaboration with accelerated ACL rehabilitation pioneer K. Donald Shelbourne, the authors wish to present a unique perspective on the evolution of ACL rehabilitation. Prior to the classic article by Paulos et al in 1981,1 literature on ACL rehabilitation was quite sparse. The basis for ACL rehabilitation at this time was founded in basic science studies conducted with animal models. In an effort to protect the graft, emphasis was placed on immobilization, extension limitation, restricted weight bearing, and delayed return to activity. Despite achieving good ligamentous stability, patients often experienced a spectrum of complications. In 1990, Shelbourne and Nitz2 proposed an accelerated rehabilitation protocol following ACL reconstruction based on clinical experience. Their program emphasized delayed surgery, earlier range of motion and weight bearing, and full extension. As a result, patients experienced better clinical outcomes while maintaining knee stability. The rehabilitation program presented in this paper is still largely based on the principles of the accelerated protocol. As evidence-based practice and the call for prospective, randomized clinical research continues, the continued progress in treating patients with this injury will be enhanced. Furthermore, clinicians are urged not to lose sight of the clinical reasoning that helped evolve the ACL rehabilitation process where it is today. PMID:21522223

  12. Deficits in Quadriceps Strength and Patient-Oriented Outcomes at Return to Activity After ACL Reconstruction

    PubMed Central

    Lepley, Lindsey K.

    2015-01-01

    Context: Side-to-side quadriceps strength deficits are linked to hazardous lower extremity mechanics and reduced function at a time when individuals are returned to activity after anterior cruciate ligament (ACL) reconstruction. As a result, generalized criteria have emerged in the literature, wherein researchers are recommending that patients be cleared for participation once side-to-side differences in strength are ≤10% of the noninjured limb. Similar recommendations exist for patient-oriented outcomes (ie, self-reported function and hop tests), where deficits of ≤10% are considered ideal at return to activity. It is unclear how many studies actually achieve these clinically recommended results. Evidence Acquisition: Articles that reported quadriceps strength deficits as compared to the contralateral limb were collected from peer-reviewed sources available on Medline and Web of Science databases (1990 through August 2014). Search terms included the following: anterior cruciate ligament OR ACL AND muscle weakness, anterior cruciate ligament OR ACL AND strength; return-to-activity AND strength; anterior cruciate ligament OR ACL AND quadriceps. Study Design: Clinical review. Level of Evidence: Level 4. Results: Average side-to-side strength deficits at 6 months postreconstruction were 23% ± 8% (range, 3%-40%), while the average at 12 months postsurgery was found to be 14% ± 6% (range, 3%-28%). The average deficits in self-reported function at 6 months (mean, 14% ± 5%) and 12 months postsurgery (mean, 13% ± 6%) were also found to be >10%. Performance on hop tests was found to be less than optimal at 6 months postsurgery (mean, 11% ± 7%), but improved at 12 months postsurgery (mean, 1.3% ± 2%). Conclusion: This review provides an up-to-date account of the typical deficits in strength and patient-oriented outcomes that exist when formalized physical therapy concludes after ACL reconstruction. Based on the studies included, it seems pertinent that researchers

  13. The anatomy of the proximal tibia in pediatric and adolescent patients: implications for ACL reconstruction and prevention of physeal arrest.

    PubMed

    Shea, Kevin G; Apel, Peter J; Pfeiffer, Ronald P; Traughber, Paul D

    2007-04-01

    Although the treatment of anterior cruciate ligament (ACL) tears in skeletally immature patients is still controversial, several studies have advocated ACL reconstruction in selected patients to prevent secondary injury. The proximal tibial physis is a structure at risk during ACL reconstruction in young patients, and physeal growth complications have been reported after surgery in this area. The relationship between the ACL and the proximal tibial physeal/apophyseal regions is poorly understood. This study examined the MRI anatomy of the ACL and the proximal tibia apophysis and epiphysis. MRIs of 59 skeletally immature knees were reviewed (Average age = 12.75 years, range 6-15) to define the anatomy of the epiphyseal and apophyseal regions. Measurements were recorded in three parasagittal planes: (1) at the lateral border of the patellar tendon, (2) the lateral edge of the ACL insertion, and (3) the medial edge of the ACL insertion. A single three-dimensional (3D) computed tomography (CT) scan was used to evaluate the position of standard drill holes used in ACL reconstruction to assess for potential degree of injury to the epiphyseal and apophyseal growth plates. In the parasagittal planes, the average height of the epiphysis was 19.6, 20.7, and 21.5 mm at the lateral border of the patellar tendon, the lateral border of the ACL, and the medial border of the ACL, respectively. At the level of the same landmarks, the apophysis extended below the physis at an average of 20.2, 16.8, and 7.0 mm, respectively. Expressed as a percentage of epiphysis height this was an average of 104, 82, and 33%, respectively. Examination of 3D CT images revealed that variations in drill hole placement had effects on the volume of injury to the proximal tibial physis and apophysis. Drill holes that started more medial, distal, and with a steeper angle of inclination reduced the amount of physis and apophysis violated when compared with holes placed more lateral, proximal, and with a

  14. Combination of Eccentric Exercise and Neuromuscular Electrical Stimulation to Improve Quadriceps Function Post-ACL Reconstruction

    PubMed Central

    Lepley, Lindsey K.; Wojtys, Edward M.; Palmieri-Smith, Riann M.

    2014-01-01

    Background Neuromuscular electrical stimulation (NMES) has been shown to reduce quadriceps activation failure (QAF), and eccentric exercise has been shown lessen muscle atrophy post-ACL reconstruction. Given that these are two critical components of quadriceps strength, intervention combining these therapies may be effective at reinstituting quadriceps function post-anterior cruciate ligament (ACL) reconstruction. Objectives To evaluate the effectiveness of a combined NMES and eccentric exercise intervention to improve the recovery of quadriceps activation and strength post-reconstruction. Design Parallel longitudinal design. Setting Laboratory. Participants Thirty-six individuals post-injury were placed into four treatment groups (N&E, NMES and eccentrics; E-only, eccentrics only; N-only, NMES-only; STND, standard of care) and ten healthy controls participated. Intervention N&E and N-only received the NMES protocol 2x per week for the first six weeks post-reconstruction. N&E and E-only received the eccentric exercise protocol 2x per week beginning six weeks post-reconstruction. Main outcome measure Quadriceps activation was assessed via the superimposed burst technique and quantified via the central activation ratio. Quadriceps strength was assessed via maximal voluntary isomeric contractions (Nm/kg). Data was gathered on three occasions: pre-operative, 12-weeks-post-surgery and at return-to-play. Results No differences in pre-operative measures existed (P>0.05). E-only recovered quadriceps activation better than N-only or STND (P<0.05). N&E and E-only recovered strength better than N-only or the STND (P<0.05) and had strength values that were similar to healthy individuals at return-to-play (P>0.05). Conclusion Eccentric exercise was capable of restoring levels of quadriceps activation and strength that were similar to those of healthy adults and better than NMES alone. PMID:25819154

  15. Panoramic Measurement and Analysis of Strain Distribution in the Human ACL Using a Photoelastic Coating Method

    NASA Astrophysics Data System (ADS)

    Hirokawa, Shunji; Yamamoto, Kouji; Kawada, Takashi

    Large and highly variable deformations of the ACL cannot be adequately quantified by one-dimensional and/or localized measurements. Since the complex anatomy of the ACL makes uniform loading of all fiber bundles almost impossible, strains on specific portions being tested are considerably altered during knee movement. To observe the ACL's entire surface, we propose a photoelastic coating method. A simulator jig was used to allow a natural motion of the knee whose medial and lateral femoral bone parts were removed in order to expose the ACL for observation. The simulator jig with the knee was mounted on a universal stand which allows tilt and swivel rotations, so that the exposed ACL might be viewed from any direction. Measurements were performed on the strain distributions over the ACL at various knee angles. The panoramic images of the photoelastic fringe patterns yielded significant results. Special attention was paid for insight into the relation between strain distribution and the directions of fiber run.

  16. Persons with reconstructed ACL exhibit altered knee mechanics during high-speed maneuvers.

    PubMed

    Lee, S-P; Chow, J W; Tillman, M D

    2014-06-01

    Anterior cruciate ligament (ACL) injury is a sports trauma that causes long-term disability. The function of the knee during dynamic activities can be severely limited even after successful surgical reconstruction. This study examined the effects of approach velocity during side-step cutting on knee joint mechanics in persons with reconstructed ACL (ACLR). 22 participants (11 with unilateral ACLR, 11 matched-controls) participated. Knee joint mechanics were tested in 3 approach conditions: counter-movement, one-step, and running. Dependent variables, including peak knee flexion, extension, valgus, varus, internal rotation, external rotation angles and corresponding peak joint moments, were assessed during the stance phase of cutting. Two 2×3 ("group" by "approach condition") mixed MANOVA tests were used to examine the effects of ACLR and approach velocity on knee mechanics. ACLR participants exhibited higher knee internal rotator moment (0.22 vs. 0.13 Nm/kg, p=0.003). Inter-group comparisons revealed that the ACLR participants exhibited significantly higher abductor and internal rotator moments only in the running condition (1.86 vs. 1.16 Nm/kg, p=0.018; 0.28 vs. 0.17 Nm/kg, p=0.010, respectively). Our findings suggested that patients with ACLR may be at increased risk of re-injury when participating in high-demand physical activities. Task demand should be considered when prescribing progressive therapeutic interventions to ACLR patients.

  17. In vivo bone tunnel evaluation of nanoparticle-grafts using an ACL reconstruction rabbit model.

    PubMed

    Grant, Sheila A; Smith, Sarah E; Schmidt, Hilary; Pfeiffer, Ferris; Kuroki, Kei; Sherman, Seth; White, Richard; Grant, David A

    2017-04-01

    Acellular human gracilis tendons conjugated with gold nanoparticles (AuNP) and hydroxyapatite nanoparticles (nano-HAp) were used as a graft in an anterior cruciate ligament (ACL) reconstruction rabbit model. The ACLs of 11 New Zealand rabbits were reconstructed using grafts conjugated without nanoparticles, with AuNP only, and with both AuNP and nano-HAp. Semi-quantitative histological scoring of bone tunnel portion of grafts was performed after 14 weeks. Bone tunnels were scored for graft degeneration, graft remodeling, percentage of new host fibrous connective, collateral connection, head-to-head connection, graft collagen fiber organization, new host fibrous connective tissue organization, and graft and interface vascularity. All grafts were intact at 14 weeks. Results of bone tunnel scoring indicate remodeling in all graft types with new organized host fibrous connective tissue, head-to-head connection to bone and mild inflammation associated with remodeling. Components of the 20 nm AuNP grafts have significantly more graft degeneration, more new host fibrous connective tissue, and more vascularity compared to crosslinked grafts. Comparison between femoral and tibial tunnel scores indicate more degeneration in femoral tunnels compared to tibial tunnels. Overall results indicated potentially enhanced remodeling from the use of 20 nm AuNP grafts. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1071-1082, 2017.

  18. COMPARATIVE STUDY OF ACL RECONSTRUCTION WITH ANATOMICAL POSITIONING OF THE TUNNELS USING THE PATELLAR TENDON VERSUS HAMSTRING TENDON

    PubMed Central

    de Pádua, Vitor Barion Castro; Maldonado, Hilário; Vilela, Júlio César Rodrigues; Provenza, Alexandre Ribeira; Monteiro, Cleverson; de Oliveira Neto, Heleno Cavalcante

    2015-01-01

    Objective: To compare ACL reconstruction with anatomical positioning of the tunnels using the hamstring or patellar tendons. Methods: We prospectively evaluated 52 patients who underwent ACL reconstruction using the Chambat's technique, with anatomical positioning of the tunnels drilled outside in. They were divided into group A, with 27 patients, using the patellar tendon as a graft, and group B, with 25 patients, using the hamstring. Results: In group A 26 patients were very satisfied or satisfied and 1 unhappy, in group B. 25 patients were very satisfied or satisfied with the procedure (p = 0.990). According to the Lysholm scale, group A had a mean score of 96.11 and group B, 95.32 (p=0.594). In relation to preoperative IKDC, 100% of the patients in group A and 92% of those in group B were IKDC C or D (p = 0.221); in the assessment with a minimum of two-year follow-up, 96% of group A and 92% of group B were IKDC A or B (p = 0.256). The Lachman test, pivot shift, return to sports activities, and the comparative difference in anterior translation (RolimeterTM) also showed no statistically significant difference. In group A, 5 patients (18.5%) were unable to kneel on a hard surface, whereas no patient in group B had this complaint. Conclusion: The anterior cruciate ligament reconstruction presents similar results using the hamstring or patellar tendon with anatomical positioning of the tunnels. Drilling the femoral tunnel outside in is a reproducible and accurate option in the correct placement the femoral tunnel. PMID:27027082

  19. Quadriceps Strength Asymmetry Following ACL Reconstruction Alters Knee Joint Biomechanics and Functional Performance at Time of Return to Activity

    PubMed Central

    Palmieri-Smith, RM; Lepley, LK

    2016-01-01

    Background Quadriceps strength deficits are observed clinically following anterior cruciate injury and reconstruction and are often not overcome despite rehabilitation. Given that quadriceps strength may be important for achieving symmetrical joint biomechanics and promoting long-term joint health, determining the magnitude of strength deficits that lead to altered mechanics is critical. Purpose To determine if the magnitude of quadriceps strength asymmetry alters knee and hip biomechanical symmetry, as well as functional performance and self-reported function. Study Design Cross-Sectional study. Methods Seventy-three patients were tested at the time they were cleared for return to activity following ACL reconstruction. Quadriceps strength and activation, scores on the International Knee Documentation Committee form, the hop for distance test, and sagittal plane lower extremity biomechanics were recorded while patients completed a single-legged hop. Results Patients with high and moderate quadriceps strength symmetry had larger central activation ratios as well as greater limb symmetry indices on the hop for distance compared to patients with low quadriceps strength symmetry (P<0.05). Similarly, knee flexion angle and external moment symmetry was higher in the patients with high and moderate quadriceps symmetry compared to those with low symmetry (P<0.05). Quadriceps strength was found to be associated with sagittal plane knee angle and moment symmetry (P<0.05). Conclusion Patients with low quadriceps strength displayed greater movement asymmetries at the knee in the sagittal plane. Quadriceps strength was related to movement asymmetries and functional performance. Rehabilitation following ACL reconstruction needs to focus on maximizing quadriceps strength, which likely will lead to more symmetrical knee biomechanics. PMID:25883169

  20. In vivo bone tunnel remodeling in symptomatic patients after ACL reconstruction: a retrospective comparison of articular and extra-articular fixation

    PubMed Central

    Mathis, Dominic T.; Rasch, Helmut; Hirschmann, Michael T.

    2015-01-01

    Summary Background there is only a paucity of studies dealing with bone remodeling within the tunnels after anterior cruciate ligament (ACL) reconstruction. The objective of this study was to evaluate the influence of tendon graft type and surgical fixation technique on bone tunnel remodeling in patients with symptomatic knees after ACL reconstruction. Methods in a retrospective study 99mTc-HDP bone tracer uptake (BTU) in SPECT/CT of 57 knees with symptoms of pain and/or instability after ACL reconstruction was investigated. All 57 knees were subdivided according their anatomy (femur and tibia), fixation (articular versus extra-articular fixation) and graft types into eight groups: femoral-articular versus extra-articular fixation using bone-patellar tendon-bone (BPTB) and hamstring autografts; tibial-articular versus extra-articular fixation using patellar tendon and hamstring autografts; BTU grading for each area of the localisation scheme were recorded. Tunnel diameter and length was measured in the CT scans. Results BTU was higher for the articular fixation in the femur and for the extra-articular fixation in the tibial tunnel. Patellar tendon graft fixation showed a significantly higher BTU in the superior-lateral and posterior-central area of the tibia, meaning the areas of the tibial tunnel near the entrance into the joint. Tunnel enlargement correlated significantly with increased BTU (p<0.05). Conclusion assessment of in vivo bone tunnel remodelling in symptomatic patients after ACL reconstruction revealed different patterns of BTU with regards to graft and fixation method. PMID:26958543

  1. Calcium phosphate-hybridized tendon graft to enhance tendon-bone healing two years after ACL reconstruction in goats

    PubMed Central

    2011-01-01

    Background We developed a novel technique to improve tendon-bone attachment by hybridizing calcium phosphate (CaP) with a tendon graft using an alternate soaking process. However, the long-term result with regard to the interface between the tendon graft and the bone is unclear. Methods We analyzed bone tunnel enlargement by computed tomography and histological observation of the interface and the tendon graft with and without the CaP hybridization 2 years after anterior cruciate ligament (ACL) reconstruction in goats using EndoButton and the postscrew technique (CaP, n = 4; control, n = 4). Results The tibial bone tunnel enlargement rates in the CaP group were lower than those in the control group (p < 0.05). In the CaP group, in the femoral and tibial bone tunnels at the anterior and posterior of the joint aperture site, direct insertion-like formation that contained a cartilage layer without tidemarks was more observed at the tendon-bone interface than in the control group (p < 0.05). Moreover, the gap area between the tendon graft and the bone was more observed at the femoral bone tunnel of the joint aperture site in the control group than in the CaP group (p < 0.05). The maturation of the tendon grafts determined using the ligament tissue maturation index was similar in both groups. Conclusions The CaP-hybridized tendon graft enhanced the tendon-bone healing 2 years after ACL reconstruction in goats. The use of CaP-hybridized tendon grafts can reduce the bone tunnel enlargement and gap area associated with the direct insertion-like formation in the interface near the joint. PMID:22166674

  2. FUNCTIONAL TESTING TO DETERMINE READINESS TO DISCONTINUE BRACE USE, ONE YEAR AFTER ACL RECONSTRUCTION

    PubMed Central

    Hunter‐Giordano, Airelle; Axe, Michael J.; Snyder‐Mackler, Lynn

    2013-01-01

    Background: While the use of functional knee braces for return to sports or high level physical activity after ACL reconstruction (ACLR) is controversial, brace use is still prevalent.1,2,3,4,5 All active patients in the practice are braced after ACLR and must pass a battery of sports tests before they return to play in their brace. Criteria include a 90% score on 4 one‐legged hop tests9 burst superimposition strength test,10 Knee Outcome Survey Activities of Daily Living Scale,8 and a global rating of knee function. Purpose: The purpose of this study was to describe the use of criterion‐based guidelines to determine if athletes who had undergone an ACLR function better with or without their functional brace, one year after surgery. Study Design: Cross‐Sectional Study Methods: Sixty‐four patients post ACLR performed 4 one‐legged hop tests,9 burst superimposition strength test,10 and completed the Knee Outcome Survey Activities of Daily Living Scale,8 and a global rating of knee function one year after surgery with and without their brace. Results: Participants included 35 men and 29 women with a mean age of 25 years. The Mean Knee Outcome Survey Activities of Daily Living score was 98%, and the global rating was 97%. Of the subjects, one patient failed hop testing by at least one criterion with and without the brace. Three additional patients failed the test while braced but passed un‐braced, and one patient passed with the brace, but failed without the brace. Subjects performed significantly better un‐braced than braced in all hop tests: single leg hop braced = 101%; un‐braced = 107% (p<0.001); cross‐over hop braced = 100%; un‐braced = 105% (p<0.001); triple hop braced = 99%; un‐braced = 101% (p=0.003); timed hop braced = 98%; un‐braced = 103% (p = 0.004). Conclusions: Sixty‐two of 64 patients continued to score above return to play criteria one year after ACLR. All but two subjects in the cohort performed better un‐braced than braced

  3. Evaluation of an intact, an ACL-deficient, and a reconstructed human knee joint finite element model.

    PubMed

    Vairis, Achilles; Stefanoudakis, George; Petousis, Markos; Vidakis, Nectarios; Tsainis, Andreas-Marios; Kandyla, Betina

    2016-02-01

    The human knee joint has a three-dimensional geometry with multiple body articulations that produce complex mechanical responses under loads that occur in everyday life and sports activities. Understanding the complex mechanical interactions of these load-bearing structures is of use when the treatment of relevant diseases is evaluated and assisting devices are designed. The anterior cruciate ligament (ACL) in the knee is one of four main ligaments that connects the femur to the tibia and is often torn during sudden twisting motions, resulting in knee instability. The objective of this work is to study the mechanical behavior of the human knee joint and evaluate the differences in its response for three different states, i.e., intact, ACL-deficient, and surgically treated (reconstructed) knee. The finite element models corresponding to these states were developed. For the reconstructed model, a novel repair device was developed and patented by the author in previous work. Static load cases were applied, as have already been presented in a previous work, in order to compare the calculated results produced by the two models the ACL-deficient and the surgically reconstructed knee joint, under the exact same loading conditions. Displacements were calculated in different directions for the load cases studied and were found to be very close to those from previous modeling work and were in good agreement with experimental data presented in literature. The developed finite element model for both the intact and the ACL-deficient human knee joint is a reliable tool to study the kinematics of the human knee, as results of this study show. In addition, the reconstructed human knee joint model had kinematic behavior similar to the intact knee joint, showing that such reconstruction devices can restore human knee stability to an adequate extent.

  4. Preoperative Predictors for Noncopers to Pass Return to Sports Criteria After ACL Reconstruction

    PubMed Central

    Zeni, Joseph; Di Stasi, Stephanie; Axe, Michael J.; Snyder-Mackler, Lynn

    2013-01-01

    Less than 50% of athletes pass criteria to return to sports (RTS) 6 months after ACL reconstruction (ACLR). Using data on 38 noncopers, we hypothesized that preoperative age, quadriceps strength index (QI), and knee flexion moments (KFM) during gait would predict the ability to pass/fail RTS criteria and that preoperative quadriceps strength gains would be predictive of passing RTS criteria. Gait analysis and strength data were collected before and after a preoperative intervention and 6 months after ACLR. Age, QI, and KFM each contributed to the predictability to pass or fail RTS criteria 6 months after ACLR. Collectively, the variables predict 69% who would pass and 82% who would fail RTS criteria 6 months after ACLR. Younger athletes who have symmetrical quadriceps strength and greater KFM were more likely to pass RTS criteria. Further, 63% of those who increased preoperative quadriceps strength passed RTS criteria, whereas 73% who did not failed. Increasing quadriceps strength in noncopers before ACLR seems warranted. PMID:22983930

  5. An intelligent recovery progress evaluation system for ACL reconstructed subjects using integrated 3-D kinematics and EMG features.

    PubMed

    Malik, Owais A; Senanayake, S M N Arosha; Zaheer, Dansih

    2015-03-01

    An intelligent recovery evaluation system is presented for objective assessment and performance monitoring of anterior cruciate ligament reconstructed (ACL-R) subjects. The system acquires 3-D kinematics of tibiofemoral joint and electromyography (EMG) data from surrounding muscles during various ambulatory and balance testing activities through wireless body-mounted inertial and EMG sensors, respectively. An integrated feature set is generated based on different features extracted from data collected for each activity. The fuzzy clustering and adaptive neuro-fuzzy inference techniques are applied to these integrated feature sets in order to provide different recovery progress assessment indicators (e.g., current stage of recovery, percentage of recovery progress as compared to healthy group, etc.) for ACL-R subjects. The system was trained and tested on data collected from a group of healthy and ACL-R subjects. For recovery stage identification, the average testing accuracy of the system was found above 95% (95-99%) for ambulatory activities and above 80% (80-84%) for balance testing activities. The overall recovery evaluation performed by the proposed system was found consistent with the assessment made by the physiotherapists using standard subjective/objective scores. The validated system can potentially be used as a decision supporting tool by physiatrists, physiotherapists, and clinicians for quantitative rehabilitation analysis of ACL-R subjects in conjunction with the existing recovery monitoring systems.

  6. Lower limb asymmetry in mechanical muscle function: A comparison between ski racers with and without ACL reconstruction.

    PubMed

    Jordan, M J; Aagaard, P; Herzog, W

    2015-06-01

    Due to a high incidence of anterior cruciate ligament (ACL) re-injury in alpine ski racers, this study aims to assess functional asymmetry in the countermovement jump (CMJ), squat jump (SJ), and leg muscle mass in elite ski racers with and without anterior cruciate ligament reconstruction (ACL-R). Elite alpine skiers with ACL-R (n = 9; 26.2 ± 11.8 months post-op) and uninjured skiers (n = 9) participated in neuromuscular screening. Vertical ground reaction force during the CMJ and SJ was assessed using dual force plate methodology to obtain phase-specific bilateral asymmetry indices (AIs) for kinetic impulse (CMJ and SJ phase-specific kinetic impulse AI). Dual x-ray absorptiometry scanning was used to assess asymmetry in lower body muscle mass. Compared with controls, ACL-R skiers had increased AI in muscle mass (P < 0.001), kinetic impulse AI in the CMJ concentric phase (P < 0.05), and the final phase of the SJ (P < 0.05). Positive associations were observed between muscle mass and AI in the CMJ concentric phase (r = 0.57, P < 0.01) as well as in the late SJ phase (r = 0.66, P < 0.01). Future research is required to assess the role of the CMJ and SJ phase-specific kinetic impulse AI as a part of a multifaceted approach for improving outcome following ACL-R in elite ski racers.

  7. Evaluation of strength muscle recovery with isokinetic, squat jump and stiffness tests in athletes with ACL reconstruction: a case control study.

    PubMed

    Jacopetti, Marco; Pasquini, Andrea; Costantino, Cosimo

    2016-05-06

    BackgroundThe anterior cruciate ligament (ACL) rupture accounting for about 50% of all knee ligament injuries. The rehabilitation program requires a long time to rebuild muscle strength and to reestablish joint mobility and neuromuscular control. The purpose of the study is to evaluate the muscle strength recovery in athletes with ACL reconstruction. MethodsWe enrolled soccer atlethes, with isolated anterior cruciate ligament rupture treated with bone-patellar tendon-bone autograft artroscopic reconstruction. Each patients were evaluated comparing operated and controlateral limb by isokinetic test and triaxial accelerometer test. Isokinetic movements tested were knee flexion-extension with concentric-concentric contraction. Accelerometer test were Squat Jump Test (SJT)  and Stiffness Test (ST). Results17 subjects were selected, there was no significant difference in isokinetic quadriceps and hamstrings results in strength and endurance values. Parameters of ST were comparable between the operated and unoperated side. In SJT a significant statistical difference was in height of jump (p=0,02) no statistical difference was evidenced in the other measures.ConclusionCurrently complete recovery of symmetric explosive strength seems to be an important parameter for evaluating the performance after ACL reconstruction and the symmetry in test results jump could be associated with an adequate return to sports. In our study the explosive strenght is lower in the limb operated than the healthy one. Explosive strength recovery with pliometric training should be included in the post-surgical rehabilitation protocol and its measurement should be performed to assess the full recovery before the restart of sport activities.

  8. ACL Revision in Synthetic ACL graft failure

    PubMed Central

    Etcheto, H. Rivarola; Zordán, J.; Escobar, G.; Collazo, C.; Palanconi, M.; Autorino, C.; Salinas, E. Alvarez

    2017-01-01

    The development of synthetic grafts as an alternative to biological grafts for reconstruction of the anterior cruciate ligament dates from 1980. The interest is awakened due to the potential advantages of: The absence of morbidity associated with donor site, and early return to sport. However, this surgical technique has had multiple complications associated with graft: mechanical failures (synthetic graft failure, loss of fixation), synovial foreign body reaction, recurrent stroke, recurrent instability and ultimately, early osteoarthritis. Objectives: We describe the synthetic graft failure LCA, intraoperative findings and details of surgical technique. Methods: Patient 35 years old, with a history of ACL reconstruction four years of evolution in another health center, consultation with the Service knee arthroscopy for acute knee pain left knee during secondary sporting event to a rotation mechanism with fixed foot. On physical examination, presents and positive Lachman maneuver Pivot. Radiografia in a widening of the tibial tunnel is observed. NMR shows a discontinuity of fibers of synthetic graft. Results: First time arthroscopic revision where synthetic plastic LCA identifies with Disruption fiber pattern. Intraoperatively, hypertrophic chronic synovitis localized predominantly in intercóndilo is observed. debridement thereof is performed, and proceeds to the extraction of the synthetic ligament. Then he was made prior cruentado and revival of the edges of the tunnel, filling them with non-irradiated structural bone allograft. At four months as planned and after confirmation by studies incorporating bone graft was performed the second time with the new plastic ACL. It was planned like a primary graft surgery with autologous hamstring prepared in fourfold form, and fixation with modified transtibial technique Biotransfix system proximal and distal screw Biocomposite (arthrex®). A quadruple graft 9 mm was obtained, making good positioning of tunnels and stable

  9. Assessing the progress of rehabilitation in patients with ACL reconstruction using the International Knee Documentation Committee Subjective Knee Form

    NASA Astrophysics Data System (ADS)

    Leguizamon, J. H.; Braidot, A.; Catalfamo Formento, P.

    2011-12-01

    There are numerous assessment tools designed to provide information on the results of reconstructive surgery of anterior cruciate ligament (ACL). They are also used for monitoring progress and facilitating clinical decision-making during the rehabilitation process. A brief summary of some existing tools specifically designed to evaluate knee ligament injuries is presented in this article. Then, one of those outcome measures, the International Knee Documentation Committee Subjective Knee Form (IKDC) was applied to a group of patients (N = 10) who had undergone surgery for ACL reconstruction. The patients attended the same physiotherapy service and followed a unified rehabilitation protocol. The assessment was performed twice: four and six months after surgery. The results showed an improvement in the rehabilitation of most patients tested (verified by a difference equal to or greater than 9 points on the IKDC outcome between measurements 1 and 2). The IKDC probed to be an instrument of quick and easy application. It provided quantitative data about the progress of rehabilitation and could be applied in everyday clinical physiotherapy practice. However, the results suggested considering the IKDC as one component of an evaluation kit to make decisions regarding the progress of the rehabilitation treatment.

  10. Methods of Voice Reconstruction

    PubMed Central

    Chen, Hung-Chi; Kim Evans, Karen F.; Salgado, Christopher J.; Mardini, Samir

    2010-01-01

    This article reviews methods of voice reconstruction. Nonsurgical methods of voice reconstruction include electrolarynx, pneumatic artificial larynx, and esophageal speech. Surgical methods of voice reconstruction include neoglottis, tracheoesophageal puncture, and prosthesis. Tracheoesophageal puncture can be performed in patients with pedicled flaps such as colon interposition, jejunum, or gastric pull-up or in free flaps such as perforator flaps, jejunum, and colon flaps. Other flaps for voice reconstruction include the ileocolon flap and jejunum. Laryngeal transplantation is also reviewed. PMID:22550443

  11. The Influence of Task Complexity on Knee Joint Kinetics Following ACL Reconstruction

    PubMed Central

    Schroeder, Megan J.; Krishnan, Chandramouli; Dhaher, Yasin Y.

    2015-01-01

    Background Previous research indicates that subjects with anterior cruciate ligament reconstruction exhibit abnormal knee joint movement patterns during functional activities like walking. While the sagittal plane mechanics have been studied extensively, less is known about the secondary planes, specifically with regard to more demanding tasks. This study explored the influence of task complexity on functional joint mechanics in the context of graft-specific surgeries. Methods In 25 participants (10 hamstring tendon graft, 6 patellar tendon graft, 9 matched controls), three-dimensional joint torques were calculated using a standard inverse dynamics approach during level walking and stair descent. The stair descent task was separated into two functionally different sub-tasks—step-to-floor and step-to-step. The differences in external knee moment profiles were compared between groups; paired differences between the reconstructed and non-reconstructed knees were also assessed. Findings The reconstructed knees, irrespective of graft type, typically exhibited significantly lower peak knee flexion moments compared to control knees during stair descent, with the differences more pronounced in the step-to-step task. Frontal plane adduction torque deficits were graft-specific and limited to the hamstring tendon knees during the step-to-step task. Internal rotation torque deficits were also primarily limited to the hamstring tendon graft group during stair descent. Collectively, these results suggest that task complexity was a primary driver of differences in joint mechanics between anterior cruciate ligament reconstructed individuals and controls, and such differences were more pronounced in individuals with hamstring tendon grafts. Interpretation The mechanical environment experienced in the cartilage during repetitive, cyclical tasks such as walking and other activities of daily living has been argued to contribute to the development of degenerative changes to the joint

  12. Neuromuscular Coordination Deficit Persists 12 Months after ACL Reconstruction But Can Be Modulated by 6 Weeks of Kettlebell Training: A Case Study in Women's Elite Soccer

    PubMed Central

    Andersen, Christoffer H.; Bencke, Jesper; Ørntoft, Christina; Linnebjerg, Connie; Hölmich, Per

    2017-01-01

    The aim of the present single-case study was to investigate the effect of 6 weeks' kettlebell training on the neuromuscular risk profile for ACL injury in a high-risk athlete returning to sport after ACL reconstruction. A female elite soccer player (age 21 years) with no previous history of ACL injury went through neuromuscular screening as measured by EMG preactivity of vastus lateralis and semitendinosus during a standardized sidecutting maneuver. Subsequently, the player experienced a noncontact ACL injury. The player was screened again following postreconstruction rehabilitation, then underwent 6-week kettlebell training, and was subsequently screened again at 6-week follow-up. Prior to and after postreconstruction rehabilitation the player demonstrated a neuromuscular profile during sidecutting known to increase the risk for noncontact ACL injury, that is, reduced EMG preactivity for semitendinosus and elevated EMG preactivity for vastus lateralis. Subsequently, the 6-week kettlebell training increased semitendinosus muscle preactivity during sidecutting by 38 percentage points to a level equivalent to a neuromuscular low-risk profile. An ACL rehabilitated female athlete with a high-risk neuromuscular profile changed to low-risk in response to 6 weeks of kettlebell training. Thus, short-term kettlebell exercise with documented high levels of medial hamstring activation was found to transfer into high medial hamstring preactivation during a sidecutting maneuver. PMID:28197354

  13. Neuromuscular Coordination Deficit Persists 12 Months after ACL Reconstruction But Can Be Modulated by 6 Weeks of Kettlebell Training: A Case Study in Women's Elite Soccer.

    PubMed

    Zebis, Mette K; Andersen, Christoffer H; Bencke, Jesper; Ørntoft, Christina; Linnebjerg, Connie; Hölmich, Per; Thorborg, Kristian; Aagaard, Per; Andersen, Lars L

    2017-01-01

    The aim of the present single-case study was to investigate the effect of 6 weeks' kettlebell training on the neuromuscular risk profile for ACL injury in a high-risk athlete returning to sport after ACL reconstruction. A female elite soccer player (age 21 years) with no previous history of ACL injury went through neuromuscular screening as measured by EMG preactivity of vastus lateralis and semitendinosus during a standardized sidecutting maneuver. Subsequently, the player experienced a noncontact ACL injury. The player was screened again following postreconstruction rehabilitation, then underwent 6-week kettlebell training, and was subsequently screened again at 6-week follow-up. Prior to and after postreconstruction rehabilitation the player demonstrated a neuromuscular profile during sidecutting known to increase the risk for noncontact ACL injury, that is, reduced EMG preactivity for semitendinosus and elevated EMG preactivity for vastus lateralis. Subsequently, the 6-week kettlebell training increased semitendinosus muscle preactivity during sidecutting by 38 percentage points to a level equivalent to a neuromuscular low-risk profile. An ACL rehabilitated female athlete with a high-risk neuromuscular profile changed to low-risk in response to 6 weeks of kettlebell training. Thus, short-term kettlebell exercise with documented high levels of medial hamstring activation was found to transfer into high medial hamstring preactivation during a sidecutting maneuver.

  14. ACL Revision

    PubMed Central

    Costa-Paz, Matias; Dubois, Julieta Puig; Zicaro, Juan Pablo; Rasumoff, Alejandro; Yacuzzi, Carlos

    2017-01-01

    Objectives: The purpose of this study was to evaluate a series of patients one year after an ACL revision with clinical evaluation and MRI, to consider their condition before returning to sports activities. Methods: A descriptive, prospective and longitudinal study was performed. A series of patients who underwent an ACL revision between March 2014 and March 2015 were evaluated after one year post surgery. They were evaluated using the Lysholm score, IKDC, Tegner, artrometry and MRI (3.0 t). A signal pattern and osteointegration was determined in the MRI. Graft signal intensity of the ACL graft using the signal/noise quotient value (SNQ) was also determined to evaluate the ligamentatization process state. Results: A total of 18 male patients were evaluated with a mean age of 31 years old.Average scores were: Lysholm 88 points, IKDC 80 points, Pre-surgical Tegner 9 points and postoperative 4 points. Artrhometry (KT1000) at 20 newtons showed a side to side difference of less than 3 mm in 88%. Only 44% of patients returned to their previous sport activity one year after revision.The MRI showed a heterogeneous signal in neoligaments in 34% of patients. SNQ showed graft integration in only 28%. Synovial fluid was found in bone-graft interphase in 44% of tunnels, inferring partial osteointegration. The heterogeneous signal was present in 50% of patients who did not return to the previous sport level activity. (Fisher statistics: p = 0.043) There were no meaningful differences in patients with auto or allografts. Conclusion: Although the clinical evaluation was satisfactory, only 44% of patients returned to the previous level of sport activity one year after the ACL surgery. The ligamentatization process was found in 28% of knees evaluated with MRI one year later. Partial osteointegration is inferred in 44%. Results showed a meaningful relation between the signal of neoligaments in the MRI and the return to sport activity in said series of patients. MRI is a useful tool

  15. Patients With Ligament Hiperlaxity With Rupture Of Previous Plastic For ACL. Reconstruction With Intra-articular And Extra-articular Combined Technics

    PubMed Central

    Astore, Ignacio; Agotegaray, Juan Ignacio; Comba, Ignacio; Bisiach, Luciana

    2017-01-01

    Introduction: In cases of patients with ligament hiperlaxity with rupture of ACL, the use of a BTB graft is recommended for its reconstruction. Our job consists of the clinical and functional assessment of a group of 10 patients with ligament laxaty according to Beighton scale, who, after surgery for ACL rupture with BTB technique, suffered a rupture of the plastic. For its reconstruction a combination of intra-articular and extra-articular techniques was used with a BTB graft in the contralateral knee, associated with a modified Lemaire technique. Methods: The series consists of 10 patients, male, average age of 24.2 years, amateur athletes, operated for a second time in March, 2011 and November, 2013, with a minimum follow-up of 24 months. They were evaluated before surgery and 24 months after surgery based on Lysholm scale, IKDC evaluation form and a physical exam (Lachman - Pivot Shift). Results: After surgery, the average in Lysholm scale was of 87.6 and 86.3 for the IKDC subjetive form. In the physical exam, 8 patients showed Lachman 1+, while none of the patients showed Pivot Shift positive. 7 patients were able to return to their usual sport activities. As a postoperative disadvantage, 6 patients reported pain in the external face of the knee in the first 6 months. And 4 patients reported a subjetive loss of full extension that did not interfere with their sport activities. Conclusion: Based on our experience and literature, we believe that the combination of both techniques, intra-articular (BTB) and extra-articular (Lemaire), is a good alternative for patients with ligament laxaty, providing positive clinical and functional results.

  16. A Novel Mass-Spring-Damper Model Analysis to Identify Landing Deficits in Athletes Returning to Sport after ACL Reconstruction.

    PubMed

    Schneider, Daniel K; Gokeler, Alli; Otten, Bert; Ford, Kevin R; Hewett, Timothy E; Divine, Jon; Colosimo, Angelo J; Heidt, Robert S; Myer, Gregory D

    2016-07-19

    A mass-spring-damper model may serve as an extension of biomechanical data from three-dimensional motion analysis and epidemiological data which help to delineate populations at-risk for anterior cruciate ligament (ACL) injuries. The purpose of this study was to evaluate such a model.\\Thirty-six ACL reconstruction (ACLR) group subjects and 67 controls (CTRL) completed single-leg drop landing and single-leg broad jump tasks. Landing ground reaction force data were collected and analyzed with a mass-spring damper model. Medians, interquartile ranges, and limb symmetry indices were calculated and comparisons were made within and between groups.During a single-leg drop landing, the ACLR group had a lower spring LSI than the CTRL group (P = 0.015) and landed with decreased stiffness in the involved limb relative to the uninvolved limb (P = 0.021). The ACLR group also had an increased damping LSI relative to the CTRL group (P = 0.045). The ACLR subjects landed with increased stiffness (P = 0.006) and decreased damping (P = 0.003) in their involved limbs compared to CTRL subjects non-dominant limbs. During a single-leg forward broad jump, the ACLR group had a greater spring LSI value than the CTRL group (P = 0.045). The CTRL group also recorded decreased damping values on their non-dominant limbs compared to the involved limbs of the ACLR group (P = 0.046).Athletes who have undergone ACLR display different lower limb dynamics than healthy controls according to a mass-spring damper model. Quadriceps dominance and leg dominance are components of ACLR athletes' landing strategies and may be identified with a mass-spring-damper model and addressed during rehabilitation.

  17. Analytical Chemistry Laboratory (ACL) procedure compendium. Volume 4, Organic methods

    SciTech Connect

    Not Available

    1993-08-01

    This interim notice covers the following: extractable organic halides in solids, total organic halides, analysis by gas chromatography/Fourier transform-infrared spectroscopy, hexadecane extracts for volatile organic compounds, GC/MS analysis of VOCs, GC/MS analysis of methanol extracts of cryogenic vapor samples, screening of semivolatile organic extracts, GPC cleanup for semivolatiles, sample preparation for GC/MS for semi-VOCs, analysis for pesticides/PCBs by GC with electron capture detection, sample preparation for pesticides/PCBs in water and soil sediment, report preparation, Florisil column cleanup for pesticide/PCBs, silica gel and acid-base partition cleanup of samples for semi-VOCs, concentrate acid wash cleanup, carbon determination in solids using Coulometrics` CO{sub 2} coulometer, determination of total carbon/total organic carbon/total inorganic carbon in radioactive liquids/soils/sludges by hot persulfate method, analysis of solids for carbonates using Coulometrics` Model 5011 coulometer, and soxhlet extraction.

  18. Hamstring Contracture After ACL Reconstruction Is Associated With an Increased Risk of Cyclops Syndrome

    PubMed Central

    Pinto, Francisco Guerra; Thaunat, Mathieu; Daggett, Matt; Kajetanek, Charles; Marques, Tiago; Guimares, Tales; Quelard, Bénédicte; Sonnery-Cottet, Bertrand

    2017-01-01

    Background: Cyclops syndrome is characterized by loss of terminal knee extension due to proliferative fibrous nodule formation in the intercondylar notch. This complication occurs in the early postoperative period after anterior cruciate ligament reconstruction (ACLR). The pathogenesis of Cyclops syndrome is not well understood. Hypothesis: Persistent hamstring contracture after ACLR is associated with an increased risk of subsequent Cyclops syndrome. Study Design: Case-control study; Level of evidence, 3. Methods: The files of 45 patients who underwent arthroscopic debridement of a Cyclops lesion after ACLR were analyzed. Recorded data included demographic information and technical details of surgery. Preoperative magnetic resonance images were also analyzed, and patients with femoral bone bruising were identified. Passive and active range of motion were recorded in all patients preoperatively and at 3 and 6 weeks after surgery to address the Cyclops lesion. Passive extension deficit was evaluated in comparison with the contralateral limb and classified as secondary to hamstring contracture when contracture was observed and palpated in the prone position and when the extension deficit was reversed after exercises performed to fatigue the hamstrings. A control group was selected using a random numbers table among our entire ACLR cohort. Statistical analysis was performed to analyze differences between the 2 groups. Results: There was no significant difference between the groups with regard to age at ACLR, sex distribution, time from injury to surgery (P > .05), proportion of professional athletes, presence of femoral bone bruise, or technical aspects of surgery. The overall extension deficit incidence was significantly higher in the Cyclops group at 3 weeks (Cyclops, 71%; control, 22%) (P < .001) and at 6 weeks (Cyclops, 60%; control, 7%) (P < .001). The extension deficit related to hamstring contracture was significantly higher in the Cyclops group at 3 weeks

  19. Biomechanical Deficiencies in Women with Semitendinosus-Gracilis ACL Reconstruction During Drop Jumps

    PubMed Central

    Ortiz, Alexis; Capo-Lugo, Carmen E.; Venegas-Rios, Heidi L.

    2014-01-01

    Objective To compare landing mechanics and neuromuscular recruitment strategies between women with semitendinosus-gracilis anterior cruciate ligament reconstruction (SG-ACLr) and non-injured women during double and single-legged drop jumps. Design Cross-sectional biomechanical study Setting Single university-based biomechanics laboratory Participants Fourteen women 1–5 years post SG-ACLr and 16 non-injured women participated in this study. Methods After anthropometric measurements, warm-up, and familiarization procedures, participants performed five trials of a double and single-legged drop jumps. Main Outcome Measurements Dynamic knee valgus was measured as the distance between knee joints during the landing phase of the double-leg drop jumps. Medial knee displacement was the outcome considered during the landing phase of the single-leg drop jumps. For both drop jumps tasks neuromuscular recruitment was evaluated through rectified normalized electromyography (EMG) activity of the quadriceps and hamstrings (amplitude and latency), and quadriceps/hamstrings EMG co-contraction ratio. Results Although the SG- ACLr group demonstrated a tendency towards a greater dynamic knee valgus during both drop jumps, these differences did not reach statistical significance. EMG data revealed different neuromuscular strategies for each group depending on the specific jump. Conclusions These findings suggest that women with SG-ACLr have a tendency towards greater dynamic knee valgus which could predispose to additional knee injuries. Rehabilitation specialists need to be aware of existing kinematic and neuromuscular deficiencies years after SG-ACLr. Taking this into consideration will aid in prescribing appropriate interventions designed to prevent re-injury. PMID:25043260

  20. Continuous ACL graft, results

    PubMed Central

    Díaz, Jorge Luis; Vega, Marcelo; Matesevach, Ivan

    2017-01-01

    Objectives: describe our technique using hamstring graft that respects the proximal continuity of Semitendinosus and uses the superior biological potential of the distal periosteum., preserving and stressing the ST reinforce the retropulsión and dynamic control of external rotation of the knee. Here the technique, results, difficulties and foundations. Methods: The sample of this research was composed of 229 cases operated between 01/03/97 and 01/03/13 in Arthroscopy Private Center., 166 male and 63 female, the postop follow-up was 86 months. Evaluated with IKDC, Lysholm, Hamstring EMG. Comparative histology study in rabbits. Results: IKDC and Lysholm score showed 93% of very good results. Conclusion: Dynamic ACL reconstruction achieves a static-dynamic stabilization of the knee. Grafts have a plus in their biological potential (proximal continuity - osteo-periosteal insertion of the tendons in the femoral tunnel). The hamstring maintains its functionality (EMG). 93% satisfactory results (IKDC, Lysholm). It is a valid surgical option in ACL injuries.

  1. Efficacy of ACL injury risk screening methods in identifying high-risk landing patterns during a sport-specific task.

    PubMed

    Fox, A S; Bonacci, J; McLean, S G; Saunders, N

    2016-06-12

    Screening methods sensitive to movement strategies that increase anterior cruciate ligament (ACL) loads are likely to be effective in identifying athletes at-risk of ACL injury. Current ACL injury risk screening methods are yet to be evaluated for their ability to identify athletes' who exhibit high-risk lower limb mechanics during sport-specific maneuvers associated with ACL injury occurrences. The purpose of this study was to examine the efficacy of two ACL injury risk screening methods in identifying high-risk lower limb mechanics during a sport-specific landing task. Thirty-two female athletes were screened using the Landing Error Scoring System (LESS) and Tuck Jump Assessment. Participants' also completed a sport-specific landing task, during which three-dimensional kinematic and kinetic data were collected. One-dimensional statistical parametric mapping was used to examine the relationships between screening method scores, and the three-dimensional hip and knee joint rotation and moment data from the sport-specific landing. Higher LESS scores were associated with reduced knee flexion from 30 to 57 ms after initial contact (P = 0.003) during the sport-specific landing; however, no additional relationships were found. These findings suggest the LESS and Tuck Jump Assessment may have minimal applicability in identifying athletes' who exhibit high-risk landing postures in the sport-specific task examined.

  2. Changes of early post-traumatic osteoarthritis in an ovine model of simulated ACL reconstruction are associated with transient acute post-injury synovial inflammation and tissue catabolism.

    PubMed

    Heard, B J; Solbak, N M; Achari, Y; Chung, M; Hart, D A; Shrive, N G; Frank, C B

    2013-12-01

    The study described here tested the hypothesis that early intra-articular inflammation is associated with the development of post-traumatic osteoarthritis (PTOA) in a sheep model. We extended previously published work in which we investigated joint gross morphology and synovial mRNA expression of inflammatory and catabolic molecules 2 weeks after anatomic Anterior cruciate ligament (ACL) autograft reconstructive surgery (ACL-R). The same variables have been analyzed at 20 weeks post surgery together with new experimental variables at both time points. Animals were sacrificed at 20 weeks post ACL-R surgery and their joints graded for signs of PTOA. Synovial samples were harvested for histological grading plus mRNA and protein analysis for a panel of inflammatory and catabolic molecules. The mRNA expression levels for this panel plus connective tissue matrix turnover molecules were also investigated in cartilage samples. Results of gross morphological assessments at 20 weeks post surgery showed some changes consistent with early OA, but indicated little progression of damage from the 2 week time point. While significant alterations in mRNA levels for synovial inflammatory and catabolic molecules were detected at 2 weeks, values had normalized by 20 weeks. Similarly, all mRNA expression levels for inflammatory and catabolic molecules in articular cartilage had returned to normal levels by 20 weeks post ACL-R surgery. We conclude that synovial inflammatory processes are initiated very early after ACL-R surgery and may instigate events that lead to the gross cartilage and joint abnormalities observed as early as 2 weeks. However, the absence of sustained inflammation and joint instability may prevent OA progression.

  3. Anterolateral Ligament Reconstruction

    PubMed Central

    Zordan, J.; Etcheto, H. Rivarola; Blanchod, C. Collazo; Palanconi, M.; Salinas, E. Álvarez; Autorino, CM; Escobar, G.

    2017-01-01

    Anterior cruciate ligament (ACL) reconstruction is a common procedure in daily practice with 75 to 97% excellent long-term results. But in certain cases, some patients perceive rotational instability, for this reason the revision rate can be 10 to 15%. Objectives: evaluate functional outcome in revisions of ACL reconstruction associated with ALL. Methods: Between July 2015 and February 2016 (11 knees) Eleven Revision ACL reconstruction were performed with ALL with double incision technique performed by the same surgical team. Inclusion criteria were: ACL reconstruction failures with a grade 2 or 3 Lachman test, a grade 3 pivot-shift without other ligamentary injury lesions associated and complete range of motion. Results: The concept of rotational instability associated with ACL injury has been described more than a decade ago. However, there is no consensus on how to quantify rotational instability in ACL injuries; so when associating an extracapsular technique. Currently there is a lack of high-level evidence comparing isolated ACL repair and associated with the modified reconstruction of ALL that allows us to define therapeutic approaches. The ALL reconstruction associate an ACL reconstruction remains a matter of study. Conclusion: We obtain excellent results in antero – posterior and rotational stability after performing the procedure.

  4. The immunosuppressive effect of Siglecs on tendon-bone healing after ACL reconstruction.

    PubMed

    Hu, Jiang; Yao, Bin; Yang, Xiao; Ma, Fang

    2015-01-01

    The quality of the bone-tendon healing is very important to the surgery outcome after anterior cruciate ligament reconstruction. The necrosis of autograft and local new blood vessels occur after the surgery. The fibroblasts and mesenchymal cells presenting in the tendon-bone interface as well as the infiltrated of neutrophils and macrophages improve the biomechanical properties of the healing. We hypothesize that immunosuppressive effect of Siglecs which present on the surface of neutrophils and macrophages play the important roles to regulate acute local inflammatory reaction, maintain the physiological environment and induce the differentiation of the pluripotent cells to form the accepted histologic structure healing of the tendon-bone interface. It might be helpful to understand the mechanism of tendon-bone healing.

  5. Predictors of Revision Surgery After Primary Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Yabroudi, Mohammad A.; Björnsson, Haukur; Lynch, Andrew D.; Muller, Bart; Samuelsson, Kristian; Tarabichi, Majd; Karlsson, Jón; Fu, Freddie H.; Harner, Christopher D.; Irrgang, James J.

    2016-01-01

    Background: Revision anterior cruciate ligament (ACL) reconstruction surgery occurs in 5% to 15% of individuals undergoing ACL reconstruction. Identifying predictors for revision ACL surgery is of essence in the pursuit of creating adequate prevention programs and to identify individuals at risk for reinjury and revision. Purpose: To determine predictors of revision ACL surgery after failed primary ACL reconstruction. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 251 participants (mean age ± SD, 26.1 ± 9.9 years) who had undergone primary ACL reconstruction 1 to 5 years earlier completed a comprehensive survey to determine predictors of revision ACL surgery at a mean 3.4 ± 1.3 years after the primary ACL reconstruction. Potential predictors that were assessed included subject characteristics (age at the time of surgery, time from injury to surgery, sex, body mass index, preinjury activity level, return to sport status), details of the initial injury (mechanism; concomitant injury to other ligaments, menisci, and cartilage), surgical details of the primary reconstruction (Lachman and pivot shift tests under anesthesia, graft type, femoral drilling technique, reconstruction technique), and postoperative course (length of rehabilitation, complications). Univariate and multivariate logistic regression analyses were performed to identify factors that predicted the need for revision ACL surgery. Results: Overall, 21 (8.4%) subjects underwent revision ACL surgery. Univariate analysis showed that younger age at the time of surgery (P = .003), participation in sports at a competitive level (P = .023), and double-bundle ACL reconstruction (P = .024) predicted increased risk of revision ACL surgery. Allograft reconstructions also demonstrated a trend toward greater risk of revision ACL surgery (P = .076). No other variables were significantly associated with revision ACL surgery. Multivariate analysis revealed that revision ACL surgery was

  6. Effects of ACL reconstruction surgery on muscle activity of the lower limb during a jump-cut maneuver in males and females

    PubMed Central

    Coats-Thomas, Margaret S.; Miranda, Daniel L.; Badger, Gary J.; Fleming, Braden C.

    2013-01-01

    We compared muscle activity of the quadriceps, hamstring, and gastrocnemius muscles when ACL-intact (ACLINT) and ACL-reconstructed (ACLREC) male and female subjects performed a jump-cut task. Surface electromyography sensors were used to evaluate time to peak muscle activity and muscle activity ratios. Rectus femoris (RF) and vastus medialis (VM) peak timing was 71 ms and 78 ms earlier in ACLINT than in ACLREC subjects, respectively. Biceps femoris (BF) peak timing was 90 ms earlier in ACLINT than in ACLREC subjects and 75 ms earlier in females than in males. Medial gastrocnemius (MG) muscle peak timing was 77 ms earlier in ACLINT than in ACLREC subjects. Lateral gastrocnemius (LG) and MG muscle peak times were 106 ms and 87 ms earlier in females than in males, respectively. The RF, VM, BF and MG peaked later in ACLREC than in ACLINT subjects. There was evidence suggesting that the loading phase quadriceps:hamstring (quad:ham) muscle activity ratio was greater in ACLREC than in ACLINT subjects. Finally, the injury risk phase quad:ham muscle activity ratio was found to be 4.8 times greater in females than in males. In conclusion, there are differences in muscle activity related to ACL status and sex that could potentially help explain graft failure risk and the sex bias. PMID:23966333

  7. Anteromedial portal versus transtibial drilling techniques in ACL reconstruction: a blinded cross-sectional study at two- to five-year follow-up

    PubMed Central

    Alentorn-Geli, Eduard; Samitier, Gonzalo; Álvarez, Pedro; Steinbacher, Gilbert

    2010-01-01

    Drilling of the femoral tunnel with the transtibial (TT) technique is widely used in bone-patellar tendon-bone (BPTB) anterior cruciate ligament (ACL) reconstruction. Recent studies suggest higher knee stability with the use of the anteromedial portal (AMP). The purpose of this study was to compare functional and clinical outcomes of BPTB ACL reconstruction using the TT or the AMP technique for drilling the femoral tunnel. All ACL reconstructions between January 2003 and April 2006 were approached for eligibility. Forty-seven patients met inclusion criteria (21 TT group and 26 AMP group). Blinded assessments of IKDC score, knee stability and range of motion, one-leg hop test, mid-quadriceps circumference, VAS for satisfaction with surgery, Lysholm and Tegner scores, and SF-12 questionnaire were obtained for both groups. Data on preoperative and postoperative surgical timing were retrospectively reviewed through the charts. The AMP group demonstrated a significantly lower recovery time from surgery to walking without crutches (p < 0.01), to return to normal life (p < 0.03), to return jogging (p < 0.03), to return training (p < 0.03), and to return to play (p < 0.03). Knee stability values measured with KT-1000, Lachman test, pivot-shift sign, and objective IKDC score assessments were significantly better for the AMP compared to TT group (p < 0.002, p < 0.03, p < 0.02, p < 0.015, respectively). No differences were found for VAS for satisfaction with surgery, Lysholm, Tegner, and SF-12 between both groups. The use of the AMP technique significantly improved the anterior-posterior and rotational knee stability, IKDC scores, and recovery time from surgery compared to the TT technique. PMID:20401753

  8. Whole Body Vibration Exercise Protocol versus a Standard Exercise Protocol after ACL Reconstruction: A Clinical Randomized Controlled Trial with Short Term Follow-Up

    PubMed Central

    Berschin, Gereon; Sommer, Björn; Behrens, Antje; Sommer, Hans-Martin

    2014-01-01

    The suitability and effectiveness of whole body vibration (WBV) exercise in rehabilitation after injury of the anterior cruciate ligament (ACL) was studied using a specially designed WBV protocol. We wanted to test the hypothesis if WBV leads to superior short term results regarding neuromuscular performance (strength and coordination) and would be less time consuming than a current standard muscle strengthening protocol. In this prospective randomized controlled clinical trial, forty patients who tore their ACL and underwent subsequent ligament reconstruction were enrolled. Patients were randomized to the whole body vibration (n=20) or standard rehabilitation exercise protocol (n=20). Both protocols started in the 2nd week after surgery. Isometric and isokinetic strength measurements, clinical assessment, Lysholm score, neuromuscular performance were conducted weeks 2, 5, 8 and 11 after surgery. Time spent for rehabilitation exercise was reduced to less than a half in the WBV group. There were no statistically significant differences in terms of clinical assessment, Lysholm score, isokinetic and isometric strength. The WBV group displayed significant better results in the stability test. In conclusion, preliminary data indicate that our whole body vibration muscle exercise protocol seems to be a good alternative to a standard exercise program in ACL-rehabilitation. Despite of its significant reduced time requirement it is at least equally effective compared to a standard rehabilitation protocol. Key points In this prospective randomized controlled clinical trial, we tested the hypothesis if WBV leads to superior short term results regarding neuromuscular performance (strength and coordination) and would be less time consuming than a current standard muscle strengthening protocol in forty patients who underwent ACL reconstruction. Time spent for rehabilitation exercise was reduced to less than a half in the WBV group as compared to the standard exercise group. Both

  9. Healing of the Acutely Injured Anterior Cruciate Ligament: Functional Treatment with the ACL-Jack, a Dynamic Posterior Drawer Brace

    PubMed Central

    Reischl, Nikolaus; Rönn, Karolin; Magnusson, Robert A.; Gautier, Emanuel; Jakob, Roland P.

    2016-01-01

    Background. The injured anterior cruciate ligament (ACL) has a limited healing capacity leading to persisting instability. Hypothesis/Purpose. To study if the application of a brace, producing a dynamic posterior drawer force, after acute ACL injury reduces initial instability. Study Design. Cohort study. Methods. Patients treated with the ACL-Jack brace were compared to controls treated with primary ACL reconstruction und controls treated nonsurgically with functional rehabilitation. Measurements included anterior laxity (Rolimeter), clinical scores (Lysholm, Tegner, and IKDC), and MRI evaluation. Patients were followed up to 24 months. Results. Patients treated with the ACL-Jack brace showed a significant improvement of anterior knee laxity comparable to patients treated with ACL reconstruction, whereas laxity persisted after nonsurgical functional rehabilitation. The failure risk (secondary reconstruction necessary) of the ACL-Jack group was however 21% (18 of 86) within 24 months. Clinical scores were similar in all treatment groups. Conclusion. Treatment of acute ACL tears with the ACL-Jack brace leads to improved anterior knee laxity compared to nonsurgical treatment with functional rehabilitation. PMID:28053787

  10. Healing of the Acutely Injured Anterior Cruciate Ligament: Functional Treatment with the ACL-Jack, a Dynamic Posterior Drawer Brace.

    PubMed

    Jacobi, Matthias; Reischl, Nikolaus; Rönn, Karolin; Magnusson, Robert A; Gautier, Emanuel; Jakob, Roland P

    2016-01-01

    Background. The injured anterior cruciate ligament (ACL) has a limited healing capacity leading to persisting instability. Hypothesis/Purpose. To study if the application of a brace, producing a dynamic posterior drawer force, after acute ACL injury reduces initial instability. Study Design. Cohort study. Methods. Patients treated with the ACL-Jack brace were compared to controls treated with primary ACL reconstruction und controls treated nonsurgically with functional rehabilitation. Measurements included anterior laxity (Rolimeter), clinical scores (Lysholm, Tegner, and IKDC), and MRI evaluation. Patients were followed up to 24 months. Results. Patients treated with the ACL-Jack brace showed a significant improvement of anterior knee laxity comparable to patients treated with ACL reconstruction, whereas laxity persisted after nonsurgical functional rehabilitation. The failure risk (secondary reconstruction necessary) of the ACL-Jack group was however 21% (18 of 86) within 24 months. Clinical scores were similar in all treatment groups. Conclusion. Treatment of acute ACL tears with the ACL-Jack brace leads to improved anterior knee laxity compared to nonsurgical treatment with functional rehabilitation.

  11. ACL Injury, Return To Play And Reinjury In The Elite, Collegiate Athlete: An Analysis Of A Single, Division I NCAA Cohort

    PubMed Central

    Kamath, Ganesh V.; Murphy, Timothy; Creighton, Robert A.; Taft, Timothy N.; Spang, Jeffrey T.

    2014-01-01

    Objectives: Graft survivorship, reinjury rates, and career length are poorly understood after ACL reconstruction in the elite, NCAA Division-I athlete. The purpose of this study was to examine the outcomes of ACL reconstruction in a Division-I athlete cohort. Methods: Retrospective chart review was performed of all Division-I athletes at a single, public university from 2000 to 2009 until completion of eligibility. Athletes with a Pre-collegiate (PC) and Intra-collegiate (IC) ACL reconstruction were separated into two cohorts. Graft survivorship, reoperation rates, and career length information was collected. Results: 35 athletes were identified with a pre-collegiate (PC) ACL reconstruction; 60 with an intra-collegiate (IC) reconstruction. The PC group had a 17.1% injury rate to the original graft, with a 20.0% rate of contralateral ACL injury. For the IC group, the reinjury rates were 1.9% to the ACL graft, with a 9.2% rate of contralateral ACL injury after an IntraCollegiate ACL reconstruction. The PC group used 78% of their total eligibility (avg 3.11 yrs). Athletes in the IC group used an average of 77% of their remaining NCAA eligibility. 88.3% of the IC group played an additional non-redshirt year after their injury. Reoperation rate for the PC group was 51.4% and 20.3% for the IC group. Conclusion: Reoperation and reinjury rates are high after ACL reconstruction in the Division-I athlete. Pre-collegiate ACL reconstruction is associated with a very high rate of repeat ACL reinjury to the graft or opposite knee (37.1%). The majority of athletes are able to return to play after successful reconstruction.

  12. Bone marrow edema-like lesions (BMELs) are associated with higher T1ρ and T2 values of cartilage in anterior cruciate ligament (ACL)-reconstructed knees: a longitudinal study

    PubMed Central

    Gong, Jingshan; Pedoia, Valentina; Facchetti, Luca; Link, Thomas M.; Ma, C. Benjamin

    2016-01-01

    Background To evaluate the longitudinal changes of bone marrow edema-like lesions (BMELs) in patients after anterior cruciate ligament (ACL) reconstruction and to investigate the effect of BMELs on cartilage matrix composition changes measured using MR T1ρ and T2 mapping. Methods Patients with acute ACL tear were enrolled in a prospective study. MR imaging was performed at baseline (before surgeries) and at 6-month, 1-year and 2-year after ACL reconstruction. MR imaging included sagittal high-resolution, 3D fast spin-echo (CUBE) sequences for BMEL evaluation, and 3D T1ρ mapping and T2 mapping for cartilage assessment. BMELs were assessed using whole-organ magnetic resonance imaging score (WORMS), and the volume of BMELs was measured by a semi-automatic method. Generalized estimating equation (GEE) was used to explore association between BMELs at baseline and cartilage changes during follow-up. Results Fifty four patients were included in the present study and 39 patients had completed 2-year follow-up. BMELs were noted in 42 injured knees (77.8%) with 105 lesions and in 7 contralateral knees (13.0%) with 9 lesions (χ2=45.763, P<0.001) at the baseline. The WORMS and volume of BMELs of the injured knees were 2.36±0.65 and 386.98±382.54 mm3 (r=0.681, P<0.001), respectively. 87 BMELs were found at baseline in 34 patients (87.2%) of the 39 patients who had completed 2 years follow-up. During the follow-up, 18 (20.7%), 12 (13.8%), and 5 (5.7%) baseline lesions were still seen at 6-month, 1-year and 2-year, respectively. The changes of BMELs prevalence regarding bone compartments over time points were statistically significant (χ2=163.660, P<0.001). Except T2 value at 6 months, T1ρ and T2 values of cartilage overlying baseline BMELs in the injured knees were higher than that of anatomically matched cartilage in the contralateral knees at baseline and each follow-up time-point. In the injured knees, GEE analysis showed that baseline BMELs were significantly

  13. Comparison of traditional advanced cardiac life support (ACLS) course instruction vs. a scenario-based, performance oriented team instruction (SPOTI) method for Korean paramedic students.

    PubMed

    Lee, Christopher C; Im, Mark; Kim, Tae Min; Stapleton, Edward R; Kim, Kyuseok; Suh, Gil Joon; Singer, Adam J; Henry, Mark C

    2010-01-01

    Current Advanced Cardiac Life Support (ACLS) course instruction involves a 2-day course with traditional lectures and limited team interaction. We wish to explore the advantages of a scenario-based performance-oriented team instruction (SPOTI) method to implement core ACLS skills for non-English-speaking international paramedic students. The objective of this study was to determine if scenario-based, performance-oriented team instruction (SPOTI) improves educational outcomes for the ACLS instruction of Korean paramedic students. Thirty Korean paramedic students were randomly selected into two groups. One group of 15 students was taught the traditional ACLS course. The other 15 students were instructed using a SPOTI method. Each group was tested using ACLS megacode examinations endorsed by the American Heart Association. All 30 students passed the ACLS megacode examination. In the traditional ACLS study group an average of 85% of the core skills were met. In the SPOTI study group an average of 93% of the core skills were met. In particular, the SPOTI study group excelled at physical examination skills such as airway opening, assessment of breathing, signs of circulation, and compression rates. In addition, the SPOTI group performed with higher marks on rhythm recognition compared to the traditional group. The traditional group performed with higher marks at providing proper drug dosages compared to the SPOTI students. However, the students enrolled in the SPOTI method resulted in higher megacode core compliance scores compared to students trained in traditional ACLS course instruction. These differences did not achieve statistical significance due to the small sample size.

  14. Anterior Cruciate Ligament (ACL) Injuries

    MedlinePlus

    ... Week of Healthy Breakfasts Shyness Anterior Cruciate Ligament (ACL) Injuries KidsHealth > For Teens > Anterior Cruciate Ligament (ACL) ... and Recovery Coping With an ACL Injury About ACL Injuries A torn anterior cruciate ligament (ACL) is ...

  15. Biomechanical Outcomes After Bio-enhanced Anterior Cruciate Ligament Repair and Anterior Cruciate Ligament Reconstruction Are Equal in a Porcine Model

    PubMed Central

    Vavken, Patrick; Fleming, Braden C.; Mastrangelo, Ashley N.; Machan, Jason T.; Murray, Martha M.

    2011-01-01

    Purpose The objective of this study was to compare the biomechanical outcomes of a new method of anterior cruciate ligament (ACL) treatment, bio-enhanced ACL repair, with ACL reconstruction in a large animal model. Methods Twenty-four skeletally immature pigs underwent unilateral ACL transection and were randomly allocated to receive bio-enhanced ACL repair with a collagen-platelet composite, allograft (bone–patellar tendon– bone) reconstruction, or no further treatment (n = 8 for each group). The structural properties and anteroposterior laxity of the experimental and contralateral ACL-intact knees were measured 15 weeks postoperatively. All dependent variables were normalized to those of the contralateral knee and compared by use of generalized linear mixed models. Results After 15 weeks, bio-enhanced ACL repair and ACL reconstruction produced superior biomechanical outcomes to ACL transection. However, there were no significant differences between bio-enhanced ACL repair and ACL reconstruction for maximum load (P = .4745), maximum displacement (P = .4217), or linear stiffness (P = .6327). There were no significant differences between the 2 surgical techniques in anteroposterior laxity at 30° (P = .7947), 60° (P = .6270), or 90° (P = .9008). Conclusions Bio-enhanced ACL repair produced biomechanical results that were not different from ACL reconstruction in a skeletally immature, large animal model, although the variability associated with both procedures was large. Both procedures produced significantly improved results over ACL transection, showing that both were effective in this model. Clinical Relevance Bio-enhanced ACL repair may 1 day provide an alternative treatment option for ACL injury. PMID:22261137

  16. Enhancement of tendon-bone healing for anterior cruciate ligament (ACL) reconstruction using bone marrow-derived mesenchymal stem cells infected with BMP-2.

    PubMed

    Dong, Yu; Zhang, Qingguo; Li, Yunxia; Jiang, Jia; Chen, Shiyi

    2012-10-22

    At present, due to the growing attention focused on the issue of tendon-bone healing, we carried out an animal study of the use of genetic intervention combined with cell transplantation for the promotion of this process. Here, the efficacy of bone marrow stromal cells infected with bone morphogenetic protein-2 (BMP-2) on tendon-bone healing was determined. A eukaryotic expression vector containing the BMP-2 gene was constructed and bone marrow-derived mesenchymal stem cells (bMSCs) were infected with a lentivirus. Next, we examined the viability of the infected cells and the mRNA and protein levels of BMP-2-infected bMSCs. Gastrocnemius tendons, gastrocnemius tendons wrapped by bMSCs infected with the control virus (bMSCs+Lv-Control), and gastrocnemius tendons wrapped by bMSCs infected with the recombinant BMP-2 virus (bMSCs+Lv-BMP-2) were used to reconstruct the anterior cruciate ligament (ACL) in New Zealand white rabbits. Specimens from each group were harvested four and eight weeks postoperatively and evaluated using biomechanical and histological methods. The bMSCs were infected with the lentivirus at an efficiency close to 100%. The BMP-2 mRNA and protein levels in bMSCs were significantly increased after lentiviral infection. The bMSCs and BMP-2-infected bMSCs on the gastrocnemius tendon improved the biomechanical properties of the graft in the bone tunnel; specifically, bMSCs infected with BMP-2 had a positive effect on tendon-bone healing. In the four-week and eight-week groups, bMSCs+Lv-BMP-2 group exhibited significantly higher maximum loads of 29.3 ± 7.4 N and 45.5 ± 11.9 N, respectively, compared with the control group (19.9 ± 6.4 N and 21.9 ± 4.9 N) (P = 0.041 and P = 0.001, respectively). In the eight-week groups, the stiffness of the bMSCs+Lv-BMP-2 group (32.5 ± 7.3) was significantly higher than that of the bMSCs+Lv-Control group (22.8 ± 7.4) or control groups (12.4 ± 6.0) (p = 0.036 and 0.001, respectively). Based on the histological

  17. The effect of neuromuscular electrical stimulation on quadriceps strength and knee function in professional soccer players: return to sport after ACL reconstruction.

    PubMed

    Taradaj, J; Halski, T; Kucharzewski, M; Walewicz, K; Smykla, A; Ozon, M; Slupska, L; Dymarek, R; Ptaszkowski, K; Rajfur, J; Pasternok, M

    2013-01-01

    The aim of this study was to assess the clinical efficacy and safety of NMES program applied in male soccer players (after ACL reconstruction) on the quadriceps muscle. The 80 participants (NMES = 40, control = 40) received an exercise program, including three sessions weekly. The individuals in NMES group additionally received neuromuscular electrical stimulation procedures on both right and left quadriceps (biphasic symmetric rectangular pulses, frequency of impulses: 2500 Hz, and train of pulses frequency: 50 Hz) three times daily (3 hours of break between treatments), 3 days a week, for one month. The tensometry, muscle circumference, and goniometry pendulum test (follow-up after 1 and 3 months) were applied. The results of this study show that NMES (in presented parameters in experiment) is useful for strengthening the quadriceps muscle in soccer athletes. There is an evidence of the benefit of the NMES in restoring quadriceps muscle mass and strength of soccer players. In our study the neuromuscular electrical stimulation appeared to be safe for biomechanics of knee joint. The pathological changes in knee function were not observed. This trial is registered with Australian and New Zealand Clinical Trials Registry ACTRN12613001168741.

  18. The Effect of NeuroMuscular Electrical Stimulation on Quadriceps Strength and Knee Function in Professional Soccer Players: Return to Sport after ACL Reconstruction

    PubMed Central

    Taradaj, J.; Halski, T.; Kucharzewski, M.; Walewicz, K.; Smykla, A.; Ozon, M.; Slupska, L.; Dymarek, R.; Ptaszkowski, K.; Rajfur, J.; Pasternok, M.

    2013-01-01

    The aim of this study was to assess the clinical efficacy and safety of NMES program applied in male soccer players (after ACL reconstruction) on the quadriceps muscle. The 80 participants (NMES = 40, control = 40) received an exercise program, including three sessions weekly. The individuals in NMES group additionally received neuromuscular electrical stimulation procedures on both right and left quadriceps (biphasic symmetric rectangular pulses, frequency of impulses: 2500 Hz, and train of pulses frequency: 50 Hz) three times daily (3 hours of break between treatments), 3 days a week, for one month. The tensometry, muscle circumference, and goniometry pendulum test (follow-up after 1 and 3 months) were applied. The results of this study show that NMES (in presented parameters in experiment) is useful for strengthening the quadriceps muscle in soccer athletes. There is an evidence of the benefit of the NMES in restoring quadriceps muscle mass and strength of soccer players. In our study the neuromuscular electrical stimulation appeared to be safe for biomechanics of knee joint. The pathological changes in knee function were not observed. This trial is registered with Australian and New Zealand Clinical Trials Registry ACTRN12613001168741. PMID:24381943

  19. Incidence and Characterization of Injury to the Infrapatellar Branch of the Saphenous Nerve after ACL Reconstruction: A Prospective Study

    PubMed Central

    Cohen, Steven B.; Ciccotti, Michael C.; Dodson, Christopher C.; Tjoumakaris, Fotios P.; Salvo, John P.; Marchetto, Paul A.; Watson, Ryan A.; Salminen, Matthew Robert; Flato, Russell R.; O'Brien, Daniel Francis

    2014-01-01

    Objectives: The infrapatellar branch of the saphenous nerve is commonly injured in anterior cruciate ligament reconstruction (ACLR) causing sensory deficits around the knee. The primary purpose of this prospective study was to determine the incidence of patient reported sensory deficits around the knee following ACLR. The secondary purpose was to determine if sensory deficits caused by intraoperative injury present at 6 weeks changed in severity and total area after 6 months and 1 year postoperatively. Methods: Two-hundred and fifty patients that underwent ACLR with or without meniscal repair were prospectively enrolled. Variables for each patient included: type of graft, direction of tibial incision, number of portals, and length of surgical incision. The grafts used were categorized into three types: Allograft (allo), hamstring autograft (HS), or patella tendon autograft (BTB). At 6 weeks, patients completed a questionnaire to ascertain any sensory deficits over their knee. Patients rated their sensory deficit on a scale from 0-10 (“0” = (no deficit) to “10” (complete lack of sensation) and shaded areas on a picture of a knee split into nine rectangular segments (3 by 3 grid) to determine the location of any numbness. Patients completed the same questionnaire at 6 months and 1 year. Any patient that was noted to have no stated numbness at 6 weeks or 6 months was noted to have completed the study. A mixed effects linear regression model was used to identify variables which were predictors for the patient-reported severity of numbness. Results: Overall, 67/221 (30.3%) patients who underwent ACLR stated that they had no numbness at 6 weeks. Of those patients who reported numbness at 6 weeks, 16.6% (25/151) considered their numbness completely resolved by six months. At 1 year, 73.2% (90/123) reported their numbness had gotten better and 14.2% (18/123) considered their numbness resolved. The most common location of numbness was along the inferolateral aspect

  20. Computational methods for image reconstruction.

    PubMed

    Chung, Julianne; Ruthotto, Lars

    2017-04-01

    Reconstructing images from indirect measurements is a central problem in many applications, including the subject of this special issue, quantitative susceptibility mapping (QSM). The process of image reconstruction typically requires solving an inverse problem that is ill-posed and large-scale and thus challenging to solve. Although the research field of inverse problems is thriving and very active with diverse applications, in this part of the special issue we will focus on recent advances in inverse problems that are specific to deconvolution problems, the class of problems to which QSM belongs. We will describe analytic tools that can be used to investigate underlying ill-posedness and apply them to the QSM reconstruction problem and the related extensively studied image deblurring problem. We will discuss state-of-the-art computational tools and methods for image reconstruction, including regularization approaches and regularization parameter selection methods. We finish by outlining some of the current trends and future challenges. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Modern methods of image reconstruction.

    NASA Astrophysics Data System (ADS)

    Puetter, R. C.

    The author reviews the image restoration or reconstruction problem in its general setting. He first discusses linear methods for solving the problem of image deconvolution, i.e. the case in which the data are a convolution of a point-spread function and an underlying unblurred image. Next, non-linear methods are introduced in the context of Bayesian estimation, including maximum likelihood and maximum entropy methods. Then, the author discusses the role of language and information theory concepts for data compression and solving the inverse problem. The concept of algorithmic information content (AIC) is introduced and is shown to be crucial to achieving optimal data compression and optimized Bayesian priors for image reconstruction. The dependence of the AIC on the selection of language then suggests how efficient coordinate systems for the inverse problem may be selected. The author also introduced pixon-based image restoration and reconstruction methods. The relation between image AIC and the Bayesian incarnation of Occam's Razor is discussed, as well as the relation of multiresolution pixon languages and image fractal dimension. Also discussed is the relation of pixons to the role played by the Heisenberg uncertainty principle in statistical physics and how pixon-based image reconstruction provides a natural extension to the Akaike information criterion for maximum likelihood. The author presents practical applications of pixon-based Bayesian estimation to the restoration of astronomical images. He discusses the effects of noise, effects of finite sampling on resolution, and special problems associated with spatially correlated noise introduced by mosaicing. Comparisons to other methods demonstrate the significant improvements afforded by pixon-based methods and illustrate the science that such performance improvements allow.

  2. Physeal-Sparing Technique for Femoral Tunnel Drilling in Pediatric Anterior Cruciate Ligament Reconstruction Using a Posteromedial Portal

    PubMed Central

    Lemos, Stephen E.; Keating, Patrick M.; Scott, Timothy P.; Siwiec, Ryan M.

    2013-01-01

    Pediatric anterior cruciate ligament (ACL) tears present a technical dilemma for orthopaedic surgeons. Multiple surgical techniques have been described to protect the distal femoral and proximal tibial physes. We present an ACL reconstruction technique performed on a 12-year-old girl with open physes who sustained an ACL tear after a noncontact twisting injury while playing soccer. A hamstring autograft reconstruction was performed by use of a posteromedial portal to drill the femoral tunnel in an all-epiphyseal fashion at the anatomic footprint of the native ACL. This case provides a new surgical technique to achieve anatomic fixation for ACL reconstruction in a skeletally immature individual using a posteromedial portal to drill a physeal-sparing lateral femoral tunnel for anatomic ACL reconstruction. This advancement may make drilling the femoral tunnel less technically challenging compared with other proposed methods while maintaining the lateral wall of the distal femur. PMID:24892013

  3. Arthroscopic anatomical double bundle anterior cruciate ligament reconstruction: A prospective longitudinal study

    PubMed Central

    Devgan, Ashish; Singh, Amanpreet; Gogna, Paritosh; Singla, Rohit; Magu, Narender Kumar; Mukhopadhyay, Reetadyuti

    2015-01-01

    Background: Single bundle anterior cruciate ligament (ACL) reconstruction has been the current standard of treatment for ACL deficiency. However, a significant subset of patients continue to report residual symptoms of instability with a poor pivot control. Cadaveric biomechanical studies have shown double bundle (DB) ACL reconstructions to restore the knee kinematics better. This study evaluates the outcome of DB ACL reconstruction. Materials and Methods: 30 consecutive patients who underwent anatomic DB ACL reconstruction were included in this prospective longitudinal study. There were all males with a mean age of 25 ± 7.45 years. All patients were prospectively evaluated using GeNouRoB (GNRB) arthrometer, functional knee scores (International Knee Documentation Committee [IKDC] and Lysholm) and postoperative magnetic resonance imaging (MRI) for comparing the graft orientation and footprint of the reconstructed ACL with that of the normal knee. Results: The average followup was 36.2 months. At the time of final followup the mean Lysholm score was 93.13 ± 3.31. As per the objective IKDC score, 26 patients (86.6%) were in Group A while 4 patients (13.3%) were in Group B. The mean differential anterior tibial translation by GNRB, arthrometer was 1.07 ± 0.8 mm (range 0.1-2.3 mm). All cases had a negative pivot shift test. MRI scans of operated and the contralateral normal knee showed the mean sagittal ACL tibial angle coronal ACL tibial angle and tibial ACL footprint to be in accordance with the values of the contralateral, normal knee. Conclusion: The study demonstrates that DB ACL reconstruction restores the ACL anatomically in terms of size and angle of orientation. However, long term studies are needed to further substantiate its role in decreasing the incidence of early osteoarthritic changes compared to the conventional single bundle reconstructions. PMID:26015600

  4. Relationship of ACL Injury and Posterior Tibial Slope With Patient Age, Sex, and Race

    PubMed Central

    Waiwaiole, Alana; Gurbani, Ajay; Motamedi, Kambiz; Seeger, Leanne; Sim, Myung Shin; Nwajuaku, Patricia; Hame, Sharon L.

    2016-01-01

    Background: Posterior tibial slope (PTS) has been proposed as a potential risk factor for anterior cruciate ligament (ACL) injury; however, studies that have examined this relationship have provided inconclusive and sometimes contradictory results. Further characterization of this relationship may enable the medical community to identify individuals at greater risk for ACL injury and possibly characterize an anatomic target during surgical reconstruction. Purpose: The primary goal was to investigate the relationship between PTS and ACL injury. The secondary goal was to determine whether there are any patient factors, such as age, race, or sex, that correlate with ACL injury and PTS. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Medical records of 221 patients who underwent magnetic resonance imaging (MRI) of the knee between January 2003 and December 2009 were reviewed. Patients were separated into 2 groups: a study group of those subjects who had undergone surgery for ACL injury (n = 107) and a control group of patients diagnosed with patellofemoral syndrome (n = 114). Demographic data were collected, and MRI images from both groups were analyzed using imaging software to obtain medial and lateral tibial slope measurements. Data were then analyzed using analysis of variance (ANOVA) comparison and a multivariable regression model to determine which, if any, patient factors were related to probability of having an ACL injury. Results: ANOVA comparison demonstrated that the study group had significantly greater values for lateral PTS (6° ± 4°; P < .001) and medial PTS (7° ± 4°; P = .002) compared with controls (5° ± 3° and 5° ± 4°, respectively). After stepwise elimination of nonsignificant variables, the final multivariable logistic regression model determined that age (odds ratio [OR], 0.94; P < .001) and lateral PTS (OR, 1.12; P = .002) had statistically significant relationships with ACL injury. Medial PTS, race, and sex were not

  5. Analytical Chemistry Laboratory (ACL) procedure compendium. Volume 3, Inorganic instrumental methods

    SciTech Connect

    Not Available

    1993-08-01

    The methods cover: C in solutions, F (electrode), elements by atomic emission spectrometry, inorganic anions by ion chromatography, Hg in water/solids/sludges, As, Se, Bi, Pb, data calculations for SST (single shell tank?) samples, Sb, Tl, Ag, Pu, O/M ratio, ignition weight loss, pH value, ammonia (N), Cr(VI), alkalinity, U, C sepn. from soil/sediment/sludge, Pu purif., total N, water, C and S, surface Cl/F, leachable Cl/F, outgassing of Ge detector dewars, gas mixing, gas isotopic analysis, XRF of metals/alloys/compounds, H in Zircaloy, H/O in metals, inpurity extraction, reduced/total Fe in glass, free acid in U/Pu solns, density of solns, Kr/Xe isotopes in FFTF cover gas, H by combustion, MS of Li and Cs isotopes, MS of lanthanide isotopes, GC operation, total Na on filters, XRF spectroscopy QC, multichannel analyzer operation, total cyanide in water/solid/sludge, free cyanide in water/leachate, hydrazine conc., ICP-MS, {sup 99}Tc, U conc./isotopes, microprobe analysis of solids, gas analysis, total cyanide, H/N{sub 2}O in air, and pH in soil.

  6. Analytical Chemistry Laboratory (ACL) procedure compendium. Volume 2, Sample preparation methods

    SciTech Connect

    Not Available

    1993-08-01

    This volume contains the interim change notice for sample preparation methods. Covered are: acid digestion for metals analysis, fusion of Hanford tank waste solids, water leach of sludges/soils/other solids, extraction procedure toxicity (simulate leach in landfill), sample preparation for gamma spectroscopy, acid digestion for radiochemical analysis, leach preparation of solids for free cyanide analysis, aqueous leach of solids for anion analysis, microwave digestion of glasses and slurries for ICP/MS, toxicity characteristic leaching extraction for inorganics, leach/dissolution of activated metal for radiochemical analysis, extraction of single-shell tank (SST) samples for semi-VOC analysis, preparation and cleanup of hydrocarbon- containing samples for VOC and semi-VOC analysis, receiving of waste tank samples in onsite transfer cask, receipt and inspection of SST samples, receipt and extrusion of core samples at 325A shielded facility, cleaning and shipping of waste tank samplers, homogenization of solutions/slurries/sludges, and test sample preparation for bioassay quality control program.

  7. Method for position emission mammography image reconstruction

    DOEpatents

    Smith, Mark Frederick

    2004-10-12

    An image reconstruction method comprising accepting coincidence datat from either a data file or in real time from a pair of detector heads, culling event data that is outside a desired energy range, optionally saving the desired data for each detector position or for each pair of detector pixels on the two detector heads, and then reconstructing the image either by backprojection image reconstruction or by iterative image reconstruction. In the backprojection image reconstruction mode, rays are traced between centers of lines of response (LOR's), counts are then either allocated by nearest pixel interpolation or allocated by an overlap method and then corrected for geometric effects and attenuation and the data file updated. If the iterative image reconstruction option is selected, one implementation is to compute a grid Siddon retracing, and to perform maximum likelihood expectation maiximization (MLEM) computed by either: a) tracing parallel rays between subpixels on opposite detector heads; or b) tracing rays between randomized endpoint locations on opposite detector heads.

  8. The potential for primary repair of the ACL

    PubMed Central

    Vavken, Patrick; Murray, Martha M

    2011-01-01

    The objective of this work is to assess the feasibility of successfully repairing the torn ACL. Two major motivators for developing a new treatment for ACL injuries are the recently reported high rates of osteoarthritis after conventional ACL reconstruction as well as the problem of how to safely treat skeletally immature patients. A key factor in developing such a technique was the identification of the main inhibitor of intrinsic ACL healing – the lack of clot formation between the two torn ends of the ligament. A bioactive and biocompatible scaffold which could be placed in the wound site to enhance cellular proliferation and biosynthesis was developed. This biomaterial has shown promising functional outcomes in several large animal models of primary repair of partial and complete ACL transection over 4 to 14 weeks, suggesting potential for a successful, future clinical application. PMID:21293237

  9. Quantitative topographic anatomy of the femoral ACL footprint: a micro-CT analysis.

    PubMed

    Norman, Daniel G; Getgood, Alan; Thornby, John; Bird, Jonathan; Turley, Glen A; Spalding, Tim; Williams, Mark A

    2014-11-01

    The femoral footprint of the anterior cruciate ligament (ACL) is a much-studied anatomic structure, predominantly due to its importance during ACL reconstruction surgery. A new technique utilising high-resolution micro-computed tomography (micro-CT) is described, allowing detailed three-dimensional (3D) quantitative analysis of this structure. Seven cadaveric knees were scanned using micro-CT, yielding 3D data with a reconstructed voxel size of 60 μm. A novel method of 3D surface extraction was developed and validated, facilitating both qualitative observation of surface details and quantitative topographic assessment using colour-coded relief maps. Images were displayed on an immersive 3D visualisation wall, and ten experienced ACL clinicians were surveyed as to the presence and morphology of osseous landmarks, providing qualitative assessment of whether such features can be reliably identified for navigation during surgery. Both quantitative analysis and qualitative assessment of the footprints in this study showed significant variability in the presence and morphology of osseous landmarks, with the lateral intercondylar ridge being objectively present in four out of seven relief maps, although reportedly seen in six out of seven cases in the qualitative study, suggesting an element of subjectivity and interpretation. This is the first study to utilise micro-CT in the study of ACL anatomy.

  10. Review of NASA ACLS research

    NASA Technical Reports Server (NTRS)

    Daugherty, R. H.

    1983-01-01

    An experimental investigation was conducted to evaluate a method of maintaining stability of an air cushion vehicle and also to evaluate several concepts to brake and steer an ACLS-equipped vehicle. The investigation used a modified airboat equipped with an air cushion landing system. The pressure relief door stability concept was characterized by the ACLS pressure time histories. The pressure relief doors vented excess cavity and lobe pressures and consistently maintained vehicle heave and pitch stability. Braking concepts were characterized by the average deceleration of the vehicle. Reduced lobe flow and cavity venting braking concepts were evaluated in this program. The cavity venting concept demonstrated the best performance, producing decelerations on the test vehicle on the same order as moderate braking with conventional wheel brakes. Steering concepts were evaluated by recording the path taken while attempting to follow a prescribed maneuver. The steering concepts evaluated included using rudders only, using differential lobe flow, and using rudders combined with a lightly loaded, nonsteering center wheel. The latter concept proved to be the most accurate means of steering the vehicle on the ACLS, producing translational deviations which, while two to three times higher than those from conventional nose gear steering, were still felt to provide reasonably precise steering control for this type vehicle.

  11. Does the lateral intercondylar ridge disappear in ACL deficient patients?

    PubMed

    van Eck, Carola F; Morse, Kenneth R; Lesniak, Bryson P; Kropf, Eric J; Tranovich, Michael J; van Dijk, C Niek; Fu, Freddie H

    2010-09-01

    The aim of this study was to determine whether there is a difference in the presence of the lateral intercondylar ridge and the lateral bifurcate ridge between patients with sub-acute and chronic ACL injuries. We hypothesized that the ridges would be present less often with chronic ACL deficiency. Twenty-five patients with a chronic ACL injury were matched for age and gender to 25 patients with a sub-acute ACL injury. The lateral intercondylar ridge and lateral bifurcate ridge were scored as either present, absent, or indeterminate due to insufficient visualization by three blinded observers. The kappa for the three observers was .61 for the lateral intercondylar ridge and .58 for the lateral bifurcate ridge. The lateral intercondylar ridge was present in 88% of the sub-acute patients and 88% of the chronic patients. The lateral bifurcate ridge was present in 48% of the sub-acute and 48% of the chronic patients. This matched-pairs case-control study was unable to show a difference in the presence of the femoral bony ridges between patients with acute and chronic ACL injuries. The authors would suggest looking for the ridges as a landmark of the native ACL insertion site during ACL reconstruction in both acute and chronic ACL injuries.

  12. Mechanoreceptor Reinnervation of Autografts Versus Allografts After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Young, Simon W.; Valladares, Roberto D.; Loi, Florence; Dragoo, Jason L.

    2016-01-01

    Background: Loss of proprioceptive function occurs after anterior cruciate ligament (ACL) rupture. Clinical, motor, and proprioceptive function is known to improve after ACL reconstruction but does not return to normal. While histological studies of human ACL allografts have been unable to demonstrate mechanoreceptor reinnervation, animal data suggest that reinnervation may occur when an autograft is used. Purpose: To compare the presence or absence of mechanoreceptors between allograft versus autograft after ACL reconstruction in humans. Study Design: Cohort study; Level of evidence, 3. Methods: Ten patients with previous ACL reconstruction presenting for either revision ACL surgery or knee arthroscopy for other reasons were enrolled in a prospective, comparative study. Five patients had a previous autograft ACL and 5 patients had an allograft. Biopsies, either from intact or ruptured grafts, were taken from identical locations as close to the femoral and tibial insertions as possible. Specimens were stained with hematoxylin-eosin (H-E) and monoclonal antibodies against neurofilament protein (NFP), known to be present in mechanoreceptor tissue. Immunohistochemical examination was carried out, and the number of NFP+ neural tissue analogs was counted and compared with that of native ACL tissue. Results: The mean time between original graft and biopsy was 6.9 years (range, 0.5-15 years). Histological examination showed significantly less NFP+ neural analogs in allograft and autograft patients than control tissue (mean number of NFP+ analogs per high-power field, 0.7 ± 0.9 [allograft] and 0.5 ± 0.8 [autograft] vs 4.7 ± 0.9 [controls]; P < .0001). There was no significant difference in NFP analogs between autograft and allograft tissue. Conclusion: We found a reduced concentration of NFP+ neural analogs in ACL grafts compared with native ACL tissue. This deficit exists irrespective of whether allograft or autograft is used. These findings may explain the continued

  13. Reconstructive methods in hearing disorders - surgical methods

    PubMed Central

    Zahnert, Thomas

    2005-01-01

    Restoration of hearing is associated in many cases with resocialisation of those affected and therefore occupies an important place in a society where communication is becoming ever faster. Not all problems can be solved surgically. Even 50 years after the introduction of tympanoplasty, the hearing results are unsatisfactory and often do not reach the threshold for social hearing. The cause of this can in most cases be regarded as incomplete restoration of the mucosal function of the middle ear and tube, which leads to ventilation disorders of the ear and does not allow real vibration of the reconstructed middle ear. However, a few are also caused by the biomechanics of the reconstructed ossicular chain. There has been progress in reconstructive middle ear surgery, which applies particularly to the development of implants. Implants made of titanium, which are distinguished by outstanding biocompatibility, delicate design and by biomechanical possibilities in the reconstruction of chain function, can be regarded as a new generation. Metal implants for the first time allow a controlled close fit with the remainder of the chain and integration of micromechanical functions in the implant. Moreover, there has also been progress in microsurgery itself. This applies particularly to the operative procedures for auditory canal atresia, the restoration of the tympanic membrane and the coupling of implants. This paper gives a summary of the current state of reconstructive microsurgery paying attention to the acousto-mechanical rules. PMID:22073050

  14. Anterior cruciate ligament reconstruction and knee osteoarthritis

    PubMed Central

    Paschos, Nikolaos K

    2017-01-01

    Anterior cruciate ligament (ACL) injury is a traumatic event that can lead to significant functional impairment and inability to participate in high-level sports-related activities. ACL reconstruction is considered the treatment of choice for symptomatic ACL-deficient patients and can assist in full functional recovery. Furthermore, ACL reconstruction restores ligamentous stability to normal, and, therefore, can potentially fully reinstate kinematics of the knee joint. As a consequence, the natural history of ACL injury could be potentially reversed via ACL reconstruction. Evidence from the literature is controversial regarding the effectiveness of ACL reconstruction in preventing the development of knee cartilage degeneration. This editorial aims to present recent high-level evidence in an attempt to answer whether ACL injury inevitably leads to osteoarthritis and whether ACL reconstruction can prevent this development or not. PMID:28361013

  15. The characteristics of EEG power spectra changes after ACL rupture

    PubMed Central

    Miao, Xin; Huang, Hongshi; Hu, Xiaoqing; Li, Dai; Yu, Yuanyuan; Ao, Yingfang

    2017-01-01

    Background Reestablishing knee stability is the core of the treatment of ACL (Anterior Cruciate Ligament) injury. Some patients still have a feeling of instability of the knee after ACL injury treatment. This unstable feeling may be caused by central nervous system changes after ACL rupture. Methods To identify the central changes after ACL rupture, EEG spectra were recorded to compare ACL patients and healthy controls when they were walking, jogging, and landing. Results There was a significant increase in delta, theta, alpha and beta band power during walking, jogging and landing in ACL patients. We also found an asymmetry phenomenon of EEG only in the ACL patients, mainly in the frontal area and central-parietal area. The asymmetry of beta band power extended to the frontal and the central area during jogging and landing task. Conclusions There were significant differences in EEG power spectra between the ACL patients and healthy people. ACL patients showed high EEG band power activities and an asymmetry phenomenon. EEG power changes were affected by movements, the asymmetry extended when performing more complicated movements. PMID:28182627

  16. Shape reconstruction methods with incomplete data

    NASA Astrophysics Data System (ADS)

    Nakahata, K.; Kitahara, M.

    2000-05-01

    Linearized inverse scattering methods are applied to the shape reconstruction of defects in elastic solids. The linearized methods are based on the Born approximation in the low frequency range and the Kirchhoff approximation in the high frequency range. The experimental measurement is performed to collect the scattering data from defects. The processed data from the measurement are fed into the linearized methods and the shape of the defect is reconstructed by two linearized methods. The importance of scattering data in the low frequency range is pointed out not only for Born inversion but also for Kirchhoff inversion. In the ultrasonic measurement for the real structure, the access points of the sensor may be limited to one side of the structural surfaces and a part of the surface. From the viewpoint of application, the incomplete scattering data are used as inputs for the shape reconstruction methods and the effect of the sensing points are discussed.

  17. Relationship Between Posterior-Inferior Tibial Slope and Bilateral Noncontact ACL Injury.

    PubMed

    Hendrix, Steven T; Barrett, Austin M; Chrea, Bopha; Replogle, William H; Hydrick, Josie M; Barrett, Gene R

    2016-10-18

    Is there a correlation between increased posterior-inferior tibial slope angle and noncontact anterior cruciate ligament (ACL) injury? Does increasing the posterior-inferior tibial slope angle increase the risk of bilateral ACL injury? A computerized relational database (Access 2007; Microsoft Inc, Redmond, Washington) was used to conduct a retrospective review of patients undergoing bilateral or unilateral ACL reconstruction surgery or treatment by a single surgeon between 1995 and 2013. Included in the study were patients with bilateral and unilateral ACL injuries and patellofemoral pain syndrome with no associated ACL deficiency. Exclusion criteria included concomitant ligament injury, previous ACL reconstruction, and previous knee surgery. Also excluded were patients who did not have plain lateral radiographs. Fifty patients were randomly selected from each group. After controlling for age and Tegner activity level, the authors found that the posterior-inferior tibial slope angle was a significant predictor (P=.002) of noncontact ACL injury. Mean posterior-inferior tibial slope angle for the bilateral, unilateral, and control groups was 11.8°±2.3°, 9.3°±2.4°, and 7.5°±2.3°, respectively. In the group with unilateral ACL injury vs the group without ACL deficiency, a 1° increase in posterior-inferior tibial slope angle (P=.03) was associated with a 20% increase in unilateral ACL injury. In those with bilateral ACL injury vs those without ACL deficiency, a 1° increase in posterior-inferior tibial slope angle (P=.001) increased bilateral knee injury by 34%. The difference between the mean angles of the control group without ACL deficiency and both the bilateral injury and unilateral injury cohorts was statistically significant (P=.003). Increased posterior-inferior tibial slope angle is associated with an increased risk of noncontact bilateral and unilateral ACL injury. [Orthopedics. 201x; xx(x):xx-xx.].

  18. The effect of the variation in ACL constitutive model on joint kinematics and biomechanics under different loads: a finite element study.

    PubMed

    Wan, Chao; Hao, Zhixiu; Wen, Shizhu

    2013-04-01

    The biomechanics and function of the anterior cruciate ligament (ACL) have been widely studied using both experimental and simulation methods. It is known that a constitutive model of joint tissue is a critical factor in the numerical simulation. Some different ligament constitutive models have been presented to describe the ACL material behavior. However, the effect of the variation in the ligament constitutive model on joint kinematics and biomechanics has still not been studied. In this paper, a three-dimensional finite element model of an intact tibiofemoral joint was reconstructed. Three ACL constitutive models were compared under different joint loads (such as anterior tibial force, varus tibial torque, and valgus tibial torque) to investigate the effect of the change of the ACL constitutive model. The three constitutive models corresponded to an isotropic hyperelasticity model, a transversely isotropic hyperelasticity model with neo-Hookean ground substance description, and a transversely isotropic hyperelastic model with nonlinear ground substance description. Although the material properties of these constitutive equations were fitted on the same uniaxial tension stress-strain curve, the change of the ACL material constitutive model was found to induce altered joint kinematics and biomechanics. The effect of different ACL constitutive equations on joint kinematics depended on both deformation direction and load type. The variation in the ACL constitutive models would influence the joint kinematic results greatly in both the anterior and internal directions under anterior tibial force as well as some other deformations such as the anterior and medial tibial translations under valgus tibial torque, and the medial tibial translation and internal rotation under varus torque. It was revealed that the transversely isotropic hyperelastic model with nonlinear ground substance description (FE model III) was the best representation of the realistic ACL property by a

  19. Effect of ACL Transection on Internal Tibial Rotation in an in Vitro Simulated Pivot Landing

    PubMed Central

    Oh, Youkeun K.; Kreinbrink, Jennifer L.; Ashton-Miller, James A.; Wojtys, Edward M.

    2011-01-01

    Background: The amount of resistance provided by the ACL (anterior cruciate ligament) to axial tibial rotation remains controversial. The goal of this study was to test the primary hypotheses that ACL transection would not significantly affect tibial rotation under the large impulsive loads associated with a simulated pivot landing but would increase anterior tibial translation. Methods: Twelve cadaveric knees (mean age of donors [and standard deviation] at the time of death, 65.0 ± 10.5 years) were mounted in a custom testing apparatus to simulate a single-leg pivot landing. A compound impulsive load was applied to the distal part of the tibia with compression (∼800 N), flexion moment (∼40 N-m), and axial tibial torque (∼17 N-m) in the presence of five trans-knee muscle forces. A differential variable reluctance transducer mounted on the anteromedial aspect of the ACL measured relative strain. With the knee initially in 15° of flexion, and after five combined compression and flexion moment (baseline) loading trials, six trials were conducted with the addition of either internal or external tibial torque (internal or external loading), and then six baseline trials were performed. The ACL was then sectioned, six baseline trials were repeated, and then six trials of either the internal or the external loading condition, whichever had initially resulted in the larger relative ACL strain, were carried out. Tibiofemoral kinematics were measured optoelectronically. The results were analyzed with a nonparametric Wilcoxon signed-rank test. Results: Following ACL transection, the increase in the normalized internal tibial rotation was significant but small (0.7°/N-m ± 0.3°/N-m to 0.8°/N-m ± 0.3°/N-m, p = 0.012), while anterior tibial translation increased significantly (3.8 ± 2.9 to 7.0 ± 2.9 mm, p = 0.017). Conclusions: ACL transection leads to a small increase in internal tibial rotation, equivalent to a 13% decrease in the dynamic rotational resistance

  20. Early anterior cruciate ligament reconstruction can save meniscus without any complications

    PubMed Central

    Hur, Chang-Ik; Song, Eun-Kyoo; Kim, Sung-Kyu; Lee, Seung-Hun; Seon, Jong-Keun

    2017-01-01

    Background: Early ACL reconstruction, before retuning to activity eliminates recurrent episodes of instability and thereby decreases chances of meniscal and cartilage injury. However, there are no clear and uniform guidelines regarding the timing of ACL reconstruction or clarity in the definition of early and delayed reconstruction to reduce the complications after reconstruction in the ACL injured knee. The purpose of this study was to compare the clinical outcome, stability, muscle power, and postural control after early and delayed anterior cruciate ligament (ACL) reconstruction. Materials and Methods: Patients who had ACL reconstruction with a quadruple hamstring tendon with a minimum 2-year followup were evaluated. Early (within 3 weeks) reconstruction group was 48 knees and delayed (more than 3 months) group was 43 knees. We compared the two groups with regard to Lysholm knee score, range of motion (ROM), Lachman test, Tegner activity scale, associated meniscal or chondral injuries, and anterior laxity. We also compared muscle strength with an isokinetic dynamometer and postural control with computed dynamic posturography at the final followup. Results: While 50% of early and 70% of delayed group had meniscal injuries (P = 0.06), of which were reparable in 42% of early group and 17% of delayed group (P = 0.04). However, there was no significant difference in cartilage injury (P = 0.14). At the final followup, no significant differences were found between two groups for Lysholm score (P = 0.28), Tegner activity scale (P = 0.27), and ROM. The stabilities regarding Lachman and pivot-shift tests, and anterior laxity also showed no significant differences between two groups. The mean extension and flexion muscles power, and postural control showed no significant inter-group differences (P > 0.05). Conclusions: Early ACL reconstruction had excellent clinical results and stability as good as delayed reconstruction without the problem of knee motion, muscle power

  1. Femoral and Tibial Tunnel Diameter and Bioabsorbable Screw Findings After Double-Bundle ACL Reconstruction in 5-Year Clinical and MRI Follow-up

    PubMed Central

    Kiekara, Tommi; Paakkala, Antti; Suomalainen, Piia; Huhtala, Heini; Järvelä, Timo

    2017-01-01

    Background: Tunnel enlargement is frequently seen in short-term follow-up after anterior cruciate ligament reconstruction (ACLR). According to new evidence, tunnel enlargement may be followed by tunnel narrowing, but the long-term evolution of the tunnels is currently unknown. Hypothesis/Purpose: The hypothesis was that tunnel enlargement is followed by tunnel narrowing caused by ossification as seen in follow-up using magnetic resonance imaging (MRI). The purpose of this study was to evaluate the ossification pattern of the tunnels, the communication of the 2 femoral and 2 tibial tunnels, and screw absorption findings in MRI. Study Design: Case series; Level of evidence, 4. Methods: Thirty-one patients underwent anatomic double-bundle ACLR with hamstring grafts and bioabsorbable interference screw fixation and were followed with MRI and clinical evaluation at 2 and 5 years postoperatively. Results: The mean tunnel enlargement at 2 years was 58% and reduced to 46% at 5 years. Tunnel ossification resulted in evenly narrowed tunnels in 44%, in conical tunnels in 48%, and fully ossified tunnels in 8%. Tunnel communication increased from 13% to 23% in the femur and from 19% to 23% in the tibia between 2 and 5 years and was not associated with knee laxity. At 5 years, 54% of the screws were not visible, with 35% of the screws replaced by a cyst and 19% fully ossified. Tunnel cysts were not associated with worse patient-reported outcomes or knee laxity. Patients with a tibial anteromedial tunnel cyst had higher Lysholm scores than patients without a cyst (93 and 84, P = .03). Conclusion: Tunnel enlargement was followed by tunnel narrowing in 5-year follow-up after double-bundle ACLR. Tunnel communication and tunnel cysts were frequent MRI findings and not associated with adverse clinical evaluation results. PMID:28203605

  2. Anterior cruciate ligament reconstruction tunnel size: causes of tunnel enlargement and implications for single versus two-stage revision reconstruction.

    PubMed

    Rizer, Magda; Foremny, Gregory Brian; Rush, Augustus; Singer, Adam D; Baraga, Michael; Kaplan, Lee D; Jose, Jean

    2017-02-01

    Anterior cruciate ligament (ACL) reconstructions have increased over the past 25 years. The increased incidence of ACL reconstructions has translated into a larger number of graft failures and revision ACL procedures. It is important to understand the causes of graft failure when evaluating for a revision ACL reconstruction and to appreciate changes in tunnel anatomy over time prior to planning revision surgery. In this manuscript, tunnel size for ACL reconstruction and implications for single-stage versus two-stage revision ACL reconstruction will be discussed, as well as causes of tunnel enlargement, including mechanical and biological factors.

  3. Bridge-Enhanced ACL Repair: A Review of the Science and the Pathway through FDA Investigational Device Approval

    PubMed Central

    Proffen, Benedikt L.; Perrone, Gabriel S.; Roberts, Gordon; Murray, Martha M.

    2016-01-01

    Injuries to the anterior cruciate ligament (ACL) are currently treated with replacement of the torn ligament with a graft of tendon harvested from elsewhere in the knee. This procedure, called "ACL reconstruction," is excellent for restoring gross stability to the knee; however, there are relatively high graft failure rates in adolescent patients,4, 12, 60 and the ACL reconstruction procedure does not prevent the premature osteoarthritis seen in patients after an ACL injury.1, 46, 52 Thus, new solutions are needed for ACL injuries. Researchers have been investigating the use of scaffolds, growth factors and cells to supplement a suture repair of the ACL (bio-enhanced repair). In this paper, we will review the varied approaches, which have been investigated for stimulating ACL healing and repair in preclinical models and how one of these technologies was able to move from promising preclinical results to FDA acceptance of an Investigational Device Exemption (IDE) application for a first-in-human study. PMID:25631206

  4. Arterial complications, venous thromboembolism and deep venous thrombosis prophylaxis after anterior cruciate ligament reconstruction: A systematic review

    PubMed Central

    Janssen, Rob Paulus Augustinus; Reijman, Max; Janssen, Daan Martijn; van Mourik, Jan Bernardus Antonius

    2016-01-01

    AIM To summarize the current knowledge on vascular complications and deep venous thrombosis (DVT) prophylaxis after anterior cruciate ligament (ACL) reconstruction. METHODS A systematic review was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement. MEDLINE, EMBASE, Cochrane, Web of Science, CINAHL, PubMed publisher, and Google scholar medical literature databases were searched up to November 10, 2015. Any arthroscopic surgical method of primary or revision intra-articular ACL reconstruction of all graft types in humans was included. A risk of bias assessment was determined. RESULTS Fourty-seven studies were included in the review. Pseudaneurysms were the most frequently reported arterial complication after ACL reconstruction, irrespective of graft type or method of graft fixation with an incidence of 0.3%. The time to diagnosis of arterial complications after ACL reconstruction varied from days to mostly weeks but even years. After ACL reconstruction without thromboprophylaxis, the incidence of DVT was 9.7%, of which 2.1% was symptomatic. The incidence of pulmonary embolism was 0.1%. Tourniquet time > 2 h was related to venous thromboembolism. Thromboprophylaxis is indicated in patients with risk factors for venous thromboembolism. CONCLUSION After ACL reconstruction, the incidence of arterial complications, symptomatic DVT and pulmonary embolism was 0.3%, 2.1% and 0.1% respectively. Arterial complications may occur with all types of arthroscopic ACL reconstruction, methods of graft fixation as well as any type of graft. Patients considered to be at moderate or high risk of venous thromboembolism should routinely receive thromboprophylaxis after ACL reconstruction. PMID:27672574

  5. Parametric reconstruction method in optical tomography.

    PubMed

    Gu, Xuejun; Ren, Kui; Masciotti, James; Hielscher, Andreas H

    2006-01-01

    Optical tomography consists of reconstructing the spatial of a medium's optical properties from measurements of transmitted light on the boundary of the medium. Mathematically this problem amounts to parameter identification for the radiative transport equation (ERT) or diffusion approximation (DA). However, this type of boundary-value problem is highly ill-posed and the image reconstruction process is often unstable and non-unique. To overcome this problem, we present a parametric inverse method that considerably reduces the number of variables being reconstructed. In this way the amount of measured data is equal or larger than the number of unknowns. Using synthetic data, we show examples that demonstrate how this approach leads to improvements in imaging quality.

  6. Bullet trajectory reconstruction - Methods, accuracy and precision.

    PubMed

    Mattijssen, Erwin J A T; Kerkhoff, Wim

    2016-05-01

    Based on the spatial relation between a primary and secondary bullet defect or on the shape and dimensions of the primary bullet defect, a bullet's trajectory prior to impact can be estimated for a shooting scene reconstruction. The accuracy and precision of the estimated trajectories will vary depending on variables such as, the applied method of reconstruction, the (true) angle of incidence, the properties of the target material and the properties of the bullet upon impact. This study focused on the accuracy and precision of estimated bullet trajectories when different variants of the probing method, ellipse method, and lead-in method are applied on bullet defects resulting from shots at various angles of incidence on drywall, MDF and sheet metal. The results show that in most situations the best performance (accuracy and precision) is seen when the probing method is applied. Only for the lowest angles of incidence the performance was better when either the ellipse or lead-in method was applied. The data provided in this paper can be used to select the appropriate method(s) for reconstruction and to correct for systematic errors (accuracy) and to provide a value of the precision, by means of a confidence interval of the specific measurement.

  7. Intermediate- to Long-Term Results of Combined Anterior Cruciate Ligament Reconstruction and Autologous Chondrocyte Implantation

    PubMed Central

    Pike, Andrew N.; Bryant, Tim; Ogura, Takahiro; Minas, Tom

    2017-01-01

    Background: Cartilage injury associated with anterior cruciate ligament (ACL) ruptures is common; however, relatively few reports exist on concurrent cartilage repair with ACL reconstruction. Autologous chondrocyte implantation (ACI) has been utilized successfully for treatment of moderate to large chondral defects. Hypothesis: ACL insufficiency with relatively large chondral defects may be effectively managed with concurrent ACL reconstruction and ACI. Study Design: Case series; Level of evidence, 4. Methods: Patients undergoing concurrent ACL primary or revision reconstruction with ACI of single or multiple cartilage defects were prospectively evaluated for a minimum 2 years. Pre- and postoperative outcome measures included the modified Cincinnati Rating Scale (MCRS), Western Ontario and McMaster Universities Osteoarthritis Index, visual analog pain scales, and postsurgery satisfaction surveys. ACI graft failure or persistent pain without functional improvement were considered treatment failures. Results: Twenty-six patients were included, with 13 primary and 13 revision ACL reconstructions performed. Mean defect total surface area was 8.4 cm2, with a mean follow-up of 95 months (range, 24-240 months). MCRS improved from 3.62 ± 1.42 to 5.54 ± 2.32, Western Ontario and McMaster Universities Osteoarthritis Index from 45.31 ± 17.27 to 26.54 ± 17.71, and visual analog pain scale from 6.19 ± 1.27 to 3.65 ± 1.77 (all Ps <.001). Eight patients were clinical failures, 69% of patients were improved at final follow-up, and 92% stated they would likely undergo the procedure again. No outcome correlation was found with regard to age, body mass index, sex, defect size/number, follow-up time, or primary versus revision ACL reconstruction. In subanalysis, revision ACL reconstructions had worse preoperative MCRS scores and greater defect surface areas. However, revision MCRS score improvements were greater, resulting in similar final functional scores when compared with

  8. The effects of ACL injury on quadriceps and hamstring torque, work and power.

    PubMed

    Pincivero, Danny M; Heller, Brandan M; Hou, Su-I

    2002-09-01

    The aim of this study was to assess isokinetic torque, work and power between non-injured, ACL (anterior cruciate ligament)-deficient and ACL-reconstructed individuals. Ten healthy, non-injured individuals, seven unilateral ACL-deficient individuals and six unilateral ACL-reconstructed individuals were assessed for isokinetic quadriceps and hamstring strength at 1.05 and 3.14 rad.s-1. Peak torque, total work, average power and the ratio of peak torque to body mass were computed for both velocities. Peak torque was also corrected for body mass, using allometric modelling. The non-injured individuals showed significantly greater quadriceps peak torque to body mass ratios than the ACL-deficient and ACL-reconstructed individuals at both velocities, and greater hamstring peak torque to body mass ratios than the ACL-deficient group at 3.14 rad.s-1 (P < 0.05). The ACL-deficient individuals displayed greater quadriceps and hamstring peak torque, total work and average power than the non-injured individuals at 1.05 rad.s-1 (P < 0.05). The ACL-deficient individuals also displayed significantly greater peak torque, total work and average power than the ACL-reconstructed individuals for the quadriceps at both velocities (P < 0.05). The ACL-deficient individuals demonstrated greater hamstring peak torque and total work than the non-injured individuals at both velocities (P < 0.05). The allometrically modelled peak torques at both isokinetic velocities demonstrated that the quadriceps muscle values were significantly higher in the non-involved than the involved limb. The hamstring peak torques corrected for body mass were significantly higher in the non-involved than the involved limb only at 1.05 rad.s-1. The main finding from the present study is that isokinetic measures in ratio-scaled or absolute units yield a different outcome and, hence, interpretation compared with the allometric approach.

  9. Magnetic flux reconstruction methods for shaped tokamaks

    NASA Astrophysics Data System (ADS)

    Tsui, Chi-Wa

    1993-12-01

    The use of a variational method permits the Grad-Shafranov (GS) equation to be solved by reducing the problem of solving the two dimensional nonlinear partial differential equation to the problem of minimizing a function of several variables. This high speed algorithm approximately solves the GS equation given a parameterization of the plasma boundary and the current profile (p' and FF' functions). The current profile parameters are treated as unknowns. The goal is to reconstruct the internal magnetic flux surfaces of a tokamak plasma and the toroidal current density profile from the external magnetic measurements. This is a classic problem of inverse equilibrium determination. The current profile parameters can be evaluated by several different matching procedures. Matching of magnetic flux and field at the probe locations using the Biot-Savart law and magnetic Green's function provides a robust method of magnetic reconstruction. The matching of poloidal magnetic field on the plasma surface provides a unique method of identifying the plasma current profile. However, the power of this method is greatly compromised by the experimental errors of the magnetic signals. The Casing principle provides a very fast way to evaluate the plasma contribution to the magnetic signals. It has the potential of being a fast matching method. The performance of this method is hindered by the accuracy of the poloidal magnetic field computed from the equilibrium solver. A flux reconstruction package has been implemented which integrates a vacuum field solver using a filament model for the plasma, a multilayer perception neural network as an interface, and the volume integration of plasma current density using Green's functions as a matching method for the current profile parameters. The flux reconstruction package is applied to compare with the ASEQ and EFIT data.

  10. Magnetic flux reconstruction methods for shaped tokamaks

    SciTech Connect

    Tsui, Chi-Wa

    1993-12-01

    The use of a variational method permits the Grad-Shafranov (GS) equation to be solved by reducing the problem of solving the 2D non-linear partial differential equation to the problem of minimizing a function of several variables. This high speed algorithm approximately solves the GS equation given a parameterization of the plasma boundary and the current profile (p` and FF` functions). The author treats the current profile parameters as unknowns. The goal is to reconstruct the internal magnetic flux surfaces of a tokamak plasma and the toroidal current density profile from the external magnetic measurements. This is a classic problem of inverse equilibrium determination. The current profile parameters can be evaluated by several different matching procedures. Matching of magnetic flux and field at the probe locations using the Biot-Savart law and magnetic Green`s function provides a robust method of magnetic reconstruction. The matching of poloidal magnetic field on the plasma surface provides a unique method of identifying the plasma current profile. However, the power of this method is greatly compromised by the experimental errors of the magnetic signals. The Casing Principle provides a very fast way to evaluate the plasma contribution to the magnetic signals. It has the potential of being a fast matching method. The performance of this method is hindered by the accuracy of the poloidal magnetic field computed from the equilibrium solver. A flux reconstruction package has been implemented which integrates a vacuum field solver using a filament model for the plasma, a multi-layer perception neural network as an interface, and the volume integration of plasma current density using Green`s functions as a matching method for the current profile parameters. The flux reconstruction package is applied to compare with the ASEQ and EFIT data. The results are promising.

  11. THE EFFECT OF CONSERVATIVELY TREATED ACL INJURY ON KNEE JOINT POSITION Sense

    PubMed Central

    Herrington, Lee

    2016-01-01

    ABSTRACT Background Proprioception is critical for effective movement patterns. However, methods of proprioceptive measurement in previous research have been inconsistent and lacking in reliability statistics making it applications to clinical practice difficult. Researchers have suggested that damage to the anterior cruciate ligament (ACL) can alter proprioceptive ability due to a loss of functioning mechanoreceptors. The majority of patients opt for reconstructive surgery following this injury. However, some patients chose conservative rehabilitation options rather than surgical intervention. Purpose The purpose of this study was to determine the effect of ACL deficiency on knee joint position sense following conservative, non-operative treatment and return to physical activity. A secondary purpose was to report the reliability and measurement error of the technique used to measure joint position sense, (JPS) and comment on the clinical utility of this measurement. Study Design Observational study design using a cross-section of ACL deficient patients and matched uninjured controls. Methods Twenty active conservatively treated ACL deficient patients who had returned to physical activity and twenty active matched controls were included in the study. Knee joint position sense was measured using a seated passive-active reproductive angle technique. The average absolute angle of error score, between 10 °-30 ° of knee flexion was determined. This error score was derived from the difference between the target and repositioning angle. Results The ACL deficient patients had a greater error score (7.9 °±3.6) and hence poorer static proprioception ability that both the contra-lateral leg (2.0 °±1.6; p = 0.0001) and the control group (2.6 °±0.9; p = 0.0001). The standard error of the mean (SEM) of this JPS technique was 0.5 ° and 0.2 ° and the minimum detectable change (MDC) was 1.3 ° and 0.4 ° on asymptomatic and symptomatic subjects

  12. Magnetic Flux Reconstruction Methods for Shaped Tokamaks

    NASA Astrophysics Data System (ADS)

    Tsui, Chi-Wa.

    The use of a variational method permits the Grad -Shafranov (GS) equation to be solved by reducing the problem of solving the 2D non-linear partial differential equation to the problem of minimizing a function of several variables. This high speed algorithm approximately solves the GS equation given a pararmeterization of the plasma boundary and the current profile (p^' and FF^' functions). We treat the current profile parameters as unknowns. The goal is to reconstruct the internal magnetic flux surfaces of a tokamak plasma and the toroidal current density profile from the external magnetic measurements. This is a classic problem of inverse equilibrium determination. The current profile parameters can be evaluated by several different matching procedures. We found that the matching of magnetic flux and field at the probe locations using the Biot-Savart law and magnetic Green's function provides a robust method of magnetic reconstruction. The matching of poloidal magnetic field on the plasma surface provides a unique method of identifying the plasma current profile. However, the power of this method is greatly compromised by the experimental errors of the magnetic signals. The Casing Principle (60) provides a very fast way to evaluate the plasma contribution to the magnetic signals. It has the potential of being a fast matching method. We found that the performance of this method is hindered by the accuracy of the poloidal magnetic field computed from the equilibrium solver. A flux reconstruction package have been implemented which integrates a vacuum field solver using a filament model for the plasma, a multi-layer perceptron neural network as a interface, and the volume integration of plasma current density using Green's functions as a matching method for the current profile parameters. The flux reconstruction package is applied to compare with the ASEQ and EFIT data. The results are promising. Also, we found that some plasmas in the tokamak Alcator C-Mod lie

  13. Anatomic Anterolateral Ligament Reconstruction Improves Postoperative Clinical Outcomes Combined with Anatomic Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Qiu, Man; Zhou, Aiguo; Zhang, Jian; Jiang, Dianming

    2016-01-01

    A significant cohort of patients is plagued by postoperative rotational instability after the anatomic anterior cruciate ligament (ACL) reconstruction surgery. Anatomic anterolateral ligament (ALL) reconstruction was performed in this study with the aim to assess the clinical role of ALL in knee’s stability and joint functions. Sixty patients were recruited and divided into three groups to perform the operations of anatomic single-bundle ACL reconstruction, anatomic double-bundle ACL reconstruction, and anatomic single-bundle ACL reconstruction + anterolateral ligament reconstruction, respectively. And then postoperative knee’s stability and joint functions were evaluated to compare the clinical outcomes among the three different kind of operations. The postoperative knee’s stability and joint functions of the anatomic double-bundle ACL reconstruction group and the anatomic single-bundle ACL reconstruction + ALL reconstruction group were better than the anatomic single-bundle ACL reconstruction group. No significant difference was observed between the anatomic double-bundle ACL reconstruction group and the anatomic single-bundle ACL reconstruction + ALL reconstruction group. The anatomic anterolateral ligament reconstruction could improve the clinical outcomes after patients performed the anatomic single-bundle anterior cruciate ligament reconstruction. This indicates that the anterolateral ligament plays a crucial role in knee’s stability and joint function, especially the rotational stability. Key points Anatomic anterolateral ligament reconstruction combined with anatomic anterior cruciate ligament reconstruction was performed to treat the patients with ACL rupture. Compared to the anatomic single-bundle ACL reconstruction group, the anatomic single-bundle ACL reconstruction + ALL reconstruction group achieve a better clinical outcomes. The results suggest that the anterolateral ligament plays a crucial role in knee’s stability and joint function

  14. Computer-assisted anterior cruciate ligament reconstruction. Four generations of development and usage.

    PubMed

    Klos, Tiburtius V S

    2014-12-01

    The purpose of this paper is to review the literature about the contribution of navigation in anterior cruciate ligament (ACL) reconstruction. The evolution of computer-assisted surgery (CAS) for ACL reconstruction has undergone several steps. These steps were divided into 4 subsequent developments: (1) positioning of ACL graft placement; (2) laxity measurement of ACL reconstruction (quality control); (3) kinematic evaluation during ACL reconstruction (navigated pivot shift); (4) case-specific individual ACL reconstruction with adjustments and additional reconstruction options. CAS has shown to improve femoral tunnel positioning, even if clinical outcomes do not improve results of manual techniques. CAS technology has helped researchers better understand the effects of different ACL reconstruction techniques and bundles replacements on joint laxity and to describe tunnel positioning in relation to native ACL insertion. CAS in ACL surgery can improve results at time zero and can improve knowledge in this field.

  15. Association Between Previous Meniscal Surgery and the Incidence of Chondral Lesions at Revision Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Brophy, Robert H.; Wright, Rick W.; David, Tal S.; McCormack, Robert G.; Sekiya, Jon K.; Svoboda, Steven J.; Huston, Laura J.; Haas, Amanda K.; Steger-May, Karen

    2013-01-01

    Background Knees undergoing revision anterior cruciate ligament (ACL) reconstruction typically have more intra-articular injuries than do knees undergoing primary reconstruction. Hypothesis Previous partial meniscectomy (PM) is associated with a higher rate of chondral lesions at revision ACL reconstruction, whereas previous meniscal repair (MR) is not associated with a higher rate of chondral lesions at revision ACL reconstruction, compared with knees undergoing revision ACL with no previous meniscal surgery. Study design Cohort study (Prevalence); Level of evidence, 2. Methods Data from a multicenter cohort was reviewed to determine the history of prior meniscal surgery (PM/MR) and the presence of grade II/III/IV chondral lesions at revision ACL reconstruction. The association between previous meniscal surgery and the incidence of chondral lesions was examined. Patient age was included as a covariate to determine if surgery type contributes predictive information independent of patient age. Results The cohort included 725 ACL revision surgeries. Chondrosis was associated with patient age (P < .0001) and previous meniscal surgery (P < .0001). After adjusting for patient age, knees with previous PM were more likely to have chondrosis than knees with previous MR (P = .003) or no previous meniscal surgery (P < .0001). There was no difference between knees without previous meniscal surgery and knees with previous MR (P = .7). Previous partial meniscectomy was associated with a higher rate of chondrosis in the same compartment compared with knees without previous meniscal surgery (P < .0001) and knees with previous MR (P ≤ .03). Conclusion The status of articular cartilage at the time of revision ACL reconstruction relates to previous meniscal surgery independent of the effect of patient age. Previous partial meniscectomy is associated with a higher incidence of articular cartilage lesions, whereas previous meniscal repair is not. Although this association may

  16. KOOS Pain as a Marker for Significant Knee Pain Two and Six Years after Primary ACL Reconstruction: A Multicenter Orthopaedic Outcomes Network (MOON) Prospective Longitudinal Cohort Study

    PubMed Central

    Wasserstein, D; Huston, LJ; Nwosu, S; Spindler, KP

    2015-01-01

    Objective The prevalence of radiographic osteoarthritis (OA) after anterior cruciate ligament reconstruction (ACLR) approaches 50%, yet the prevalence of significant knee pain is unknown. We applied three different models of Knee injury and Osteoarthritis Outcome Score (KOOS) thresholds for significant knee pain to an ACLR cohort to identify prevalence and risk factors. Design Multicenter Orthopaedic Outcomes Network (MOON) prospective cohort patients with a unilateral primary ACLR and normal contralateral knee were assessed at 2 and 6 years. Independent variables included patient demographics, validated Patient Reported Outcomes (PRO; Marx activity score, KOOS), and surgical characteristics. Models included: (1) KOOS criteria for a painful knee = quality of life subscale <87.5 and ≥2 of: KOOSpain <86.1, KOOSsymptoms <85.7, KOOSADL <86.8, or KOOSsports/rec <85.0; (2) KOOSpain subscale score ≤72 (≥2 standard deviations below population mean); (3) 10-point KOOSpain drop from 2 to 6 years. Proportional odds models (alpha≤0.05) were used. Results 1,761 patients of median age 23 years, median BMI 24.8 kg/m2 and 56% male met inclusion, with 87% (1530/1761) and 86% (1506/1761) follow-up at 2 and 6 years, respectively. At 6 years, n=592 (39%), n=131 (9%) and n=169 (12%) met criteria for models #1 through #3, respectively. The most consistent and strongest independent risk factor at both time-points was subsequent ipsilateral knee surgery. Low 2-year Marx activity score increased the odds of a painful knee at 6 years. Conclusions Significant knee pain is prevalent after ACLR; with those who undergo subsequent ipsilateral surgery at greatest risk. The relationship between pain and structural OA warrants further study. PMID:26072385

  17. Effect of Timing of Surgery in Partially Injured ACLs.

    PubMed

    Li, Bin; Bai, Lunhao; Fu, Yonghui; Wang, Guangbin; He, Ming; Wang, Jiashi

    2012-05-01

    The purpose of this study was to explore the optimal timing for surgical intervention of partially injured anterior cruciate ligaments (ACL). Thirty-eight patients were divided into early (n=17) or delayed (n=21) surgery groups based on the interval between injury and surgery. Minimum follow-up was 2 years. The outcome measures used were the International Knee Documentation Committee score, Lysholm knee score, Tegner activity rating, range of motion, and arthrometer measurements. The findings of this study indicate that early surgical reconstruction of partially ruptured ACLs did not result in arthrofibrosis but may prevent secondary loosening of the intact bundles and further meniscal and chondral injury.

  18. Anterior Cruciate Ligament (ACL) Injuries

    MedlinePlus

    ... what the surgeon advises. previous continue Rehab and Recovery Recovery from ACL surgery can take from 6 months ... frequent therapy, but they won't necessarily speed recovery. In the early stages of recovery, a doctor ...

  19. Anterior cruciate ligament (ACL) injury

    MedlinePlus

    ... proper techniques when playing sports or exercising. Some college sports programs teach athletes how to reduce stress placed on the ACL. The use of knee braces during vigorous athletic activity ( ...

  20. Athletic Performance at the National Basketball Association Combine After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Mehran, Nima; Williams, Phillip N.; Keller, Robert A.; Khalil, Lafi S.; Lombardo, Stephen J.; Kharrazi, F. Daniel

    2016-01-01

    Background: Anterior cruciate ligament (ACL) injuries are significant injuries in elite-level basketball players. In-game statistical performance after ACL reconstruction has been demonstrated; however, few studies have reviewed functional performance in National Basketball Association (NBA)–caliber athletes after ACL reconstruction. Purpose: To compare NBA Combine performance of athletes after ACL reconstruction with an age-, size-, and position-matched control group of players with no previous reported knee injury requiring surgery. We hypothesized that there is no difference between the 2 groups in functional performance. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 1092 NBA-caliber players who participated in the NBA Combine between 2000 and 2015 were reviewed. Twenty-one athletes were identified as having primary ACL reconstruction prior to participation in the combine. This study group was compared with an age-, size-, and position-matched control group in objective functional performance testing, including the shuttle run test, lane agility test, three-quarter court sprint, vertical jump (no step), and maximum vertical jump (running start). Results: With regard to quickness and agility, both ACL-reconstructed athletes and controls scored an average of 11.5 seconds in the lane agility test and 3.1 seconds in the shuttle run test (P = .745 and .346, respectively). Speed and acceleration was measured by the three-quarter court sprint, in which both the study group and the control group averaged 3.3 seconds (P = .516). In the maximum vertical jump, which demonstrates an athlete’s jumping ability with a running start, the ACL reconstruction group had an average height of 33.6 inches while the controls averaged 33.9 inches (P = .548). In the standing vertical jump, the ACL reconstruction group averaged 28.2 inches while the control group averaged 29.2 inches (P = .067). Conclusion: In athletes who are able to return to sport

  1. Inverse polynomial reconstruction method in DCT domain

    NASA Astrophysics Data System (ADS)

    Dadkhahi, Hamid; Gotchev, Atanas; Egiazarian, Karen

    2012-12-01

    The discrete cosine transform (DCT) offers superior energy compaction properties for a large class of functions and has been employed as a standard tool in many signal and image processing applications. However, it suffers from spurious behavior in the vicinity of edge discontinuities in piecewise smooth signals. To leverage the sparse representation provided by the DCT, in this article, we derive a framework for the inverse polynomial reconstruction in the DCT expansion. It yields the expansion of a piecewise smooth signal in terms of polynomial coefficients, obtained from the DCT representation of the same signal. Taking advantage of this framework, we show that it is feasible to recover piecewise smooth signals from a relatively small number of DCT coefficients with high accuracy. Furthermore, automatic methods based on minimum description length principle and cross-validation are devised to select the polynomial orders, as a requirement of the inverse polynomial reconstruction method in practical applications. The developed framework can considerably enhance the performance of the DCT in sparse representation of piecewise smooth signals. Numerical results show that denoising and image approximation algorithms based on the proposed framework indicate significant improvements over wavelet counterparts for this class of signals.

  2. Accelerated augmented Lagrangian method for few-view CT reconstruction

    NASA Astrophysics Data System (ADS)

    Wu, Junfeng; Mou, Xuanqin

    2012-03-01

    Recently iterative reconstruction algorithms with total variation (TV) regularization have shown its tremendous power in image reconstruction from few-view projection data, but it is much more demanding in computation. In this paper, we propose an accelerated augmented Lagrangian method (ALM) for few-view CT reconstruction with total variation regularization. Experimental phantom results demonstrate that the proposed method not only reconstruct high quality image from few-view projection data but also converge fast to the optimal solution.

  3. Muscle function is associated with future patient-reported outcomes in young adults with ACL injury

    PubMed Central

    Flosadottir, Vala; Roos, Ewa M; Ageberg, Eva

    2016-01-01

    Background/aim Consequences of an anterior cruciate ligament (ACL) injury include worse patient-reported outcomes (PROs) and a decrease in activity level. Muscle function can be improved by targeted exercise. Our aims were to investigate cross-sectional and longitudinal associations among lower extremity muscle function and PROs after ACL injury. Methods Fifty-four participants (15 women, mean 30 years) with ACL injury or reconstruction, from the Knee Anterior Cruciate Ligament, Nonsurgical versus Surgical Treatment (KANON) trial (ISRCTN84752559), were assessed with hop performance, muscle power and postural orientation 3 years (SD 0.85) after ACL injury. PROs at 3 and 5 years after injury included Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales Function in sport and recreation (KOOS Sport/rec) and Knee-related Quality of life (KOOS QoL), KOOS item Q3 (KOOS Q3), Tegner Activity Scale and Activity Rating Scale (ARS). Partial Spearman's rank-order correlation was used to analyse correlations between muscle function and PROs, controlling for gender and treatment. Results Numerous cross-sectional correlations were observed between muscle function and PROs (rsp≈0.3–0.5, p≤0.045). Worse hop performance and worse postural orientation were associated with worse KOOS scores 2 years later (rsp≥0.280, p≤0.045). Worse muscle power was associated with lower future ARS scores (rsp=0.281, p=0.044). Conclusions The moderate associations suggest that improving muscle function during rehabilitation could improve present and future PROs. PMID:27900196

  4. Hybrid Method for Tokamak MHD Equilibrium Configuration Reconstruction

    NASA Astrophysics Data System (ADS)

    He, Hong-Da; Dong, Jia-Qi; Zhang, Jin-Hua; Jiang, Hai-Bin

    2007-02-01

    A hybrid method for tokamak MHD equilibrium configuration reconstruction is proposed and employed in the modified EFIT code. This method uses the free boundary tokamak equilibrium configuration reconstruction algorithm with one boundary point fixed. The results show that the position of the fixed point has explicit effects on the reconstructed divertor configurations. In particular, the separatrix of the reconstructed divertor configuration precisely passes the required position when the hybrid method is used in the reconstruction. The profiles of plasma parameters such as pressure and safety factor for reconstructed HL-2A tokamak configurations with the hybrid and the free boundary methods are compared. The possibility for applications of the method to swing the separatrix strike point on the divertor target plate is discussed.

  5. Investigation of a hybrid method of soft tissue graft fixation for anterior cruciate ligament reconstruction.

    PubMed

    Au, Anthony G; Otto, David D; Raso, V James; Amirfazli, Alidad

    2005-04-01

    To increase knee stability following anterior cruciate ligament (ACL) reconstruction, development of increasingly stronger and stiffer fixation is required. This study assessed the initial pullout force, stiffness of fixation, and failure modes for a novel hybrid fixation method combining periosteal and direct fixation using porcine femoral bone. A soft tissue graft was secured by combining both an interference screw and an EndoButton (Smith and Nephew Endoscopy, Andover, MA). The results were compared with the traditional direct fixation method using a titanium interference screw. Twenty porcine hindlimbs were divided into two groups. Specimens were loaded in line with the bone tunnel on a materials testing machine. Maximum pullout force of the hybrid fixation (588+/-37 N) was significantly greater than with an interference screw alone (516+/-37 N). The stiffness of the hybrid fixation (52.1+/-12.8 N/mm) was similar to that of screw fixation (56.5+/-10.2 N/mm). Graft pullout was predominant for screw fixation, whereas a combination of graft pullout and graft failure was seen for hybrid fixation. These results indicate that initial pullout force of soft tissue grafts can be increased by using the suggested novel hybrid fixation method.

  6. A Comparative Study of Different Reconstruction Schemes for a Reconstructed Discontinuous Galerkin Method on Arbitrary Grids

    SciTech Connect

    Hong Luo; Hanping Xiao; Robert Nourgaliev; Chunpei Cai

    2011-06-01

    A comparative study of different reconstruction schemes for a reconstruction-based discontinuous Galerkin, termed RDG(P1P2) method is performed for compressible flow problems on arbitrary grids. The RDG method is designed to enhance the accuracy of the discontinuous Galerkin method by increasing the order of the underlying polynomial solution via a reconstruction scheme commonly used in the finite volume method. Both Green-Gauss and least-squares reconstruction methods and a least-squares recovery method are implemented to obtain a quadratic polynomial representation of the underlying discontinuous Galerkin linear polynomial solution on each cell. These three reconstruction/recovery methods are compared for a variety of compressible flow problems on arbitrary meshes to access their accuracy and robustness. The numerical results demonstrate that all three reconstruction methods can significantly improve the accuracy of the underlying second-order DG method, although the least-squares reconstruction method provides the best performance in terms of both accuracy and robustness.

  7. A new target reconstruction method considering atmospheric refraction

    NASA Astrophysics Data System (ADS)

    Zuo, Zhengrong; Yu, Lijuan

    2015-12-01

    In this paper, a new target reconstruction method considering the atmospheric refraction is presented to improve 3D reconstruction accuracy in long rang surveillance system. The basic idea of the method is that the atmosphere between the camera and the target is partitioned into several thin layers radially in which the density is regarded as uniform; Then the reverse tracking of the light propagation path from sensor to target was carried by applying Snell's law at the interface between layers; and finally the average of the tracked target's positions from different cameras is regarded as the reconstructed position. The reconstruction experiments were carried, and the experiment results showed that the new method have much better reconstruction accuracy than the traditional stereoscopic reconstruction method.

  8. A Comparison between Clinical Results of Selective Bundle and Double Bundle Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Yoo, Yon-Sik; Song, Si Young; Yang, Cheol Jung; Ha, Jong Mun; Kim, Yoon Sang

    2016-01-01

    Purpose The purpose of this study was to compare the clinical outcomes of arthroscopic anatomical double bundle (DB) anterior cruciate ligament (ACL) reconstruction with either selective anteromedial (AM) or posterolateral (PL) bundle reconstruction while preserving a relatively healthy ACL bundle. Materials and Methods The authors evaluated 98 patients with a mean follow-up of 30.8±4.0 months who had undergone DB or selective bundle ACL reconstructions. Of these, 34 cases underwent DB ACL reconstruction (group A), 34 underwent selective AM bundle reconstruction (group B), and 30 underwent selective PL bundle reconstructions (group C). These groups were compared with respect to Lysholm and International Knee Documentation Committee (IKDC) score, side-to-side differences of anterior laxity measured by KT-2000 arthrometer at 30 lbs, and stress radiography and Lachman and pivot shift test results. Pre- and post-operative data were objectively evaluated using a statistical approach. Results The preoperative anterior instability measured by manual stress radiography at 90° of knee flexion in group A was significantly greater than that in groups B and C (all p<0.001). At last follow-up, mean side-to-side instrumented laxities measured by the KT-2000 and manual stress radiography were significantly improved from preoperative data in all groups (all p<0.001). There were no significant differences between the three groups in anterior instability measured by KT-2000 arthrometer, pivot shift, or functional scores. Conclusion Selective bundle reconstruction in partial ACL tears offers comparable clinical results to DB reconstruction in complete ACL tears. PMID:27401652

  9. The ACL Message Passing Library

    SciTech Connect

    Painter, J.; McCormick, P.; Krogh, M.; Hansen, C.; Colin de Verdiere, G.

    1995-09-01

    This paper presents the ACL (Advanced Computing Lab) Message Passing Library. It is a high throughput, low latency communications library, based on Thinking Machines Corp.`s CMMD, upon which message passing applications can be built. The library has been implemented on the Cray T3D, Thinking Machines CM-5, SGI workstations, and on top of PVM.

  10. Knee biomechanics during a jump-cut maneuver: Effects of gender & ACL surgery

    PubMed Central

    Miranda, Daniel L.; Fadale, Paul D.; Hulstyn, Michael J.; Shalvoy, Robert M.; Machan, Jason T.; Fleming, Braden C.

    2012-01-01

    Purpose The purpose of this study was to compare kinetic and knee kinematic measurements from male and female ACL-intact (ACLINT) and ACL-reconstructed (ACLREC) subjects during a jump-cut maneuver using biplanar videoradiography. Methods Twenty subjects were recruited; 10 ACLINT (5 males, 5 females) and 10 ACLREC (4 males, 6 females; five years post surgery). Each subject performed a jump-cut maneuver by landing on a single leg and performing a 45° side-step cut. Ground reaction force was measured by a force plate and expressed relative to body weight. Six-degree-of-freedom knee kinematics were determined from a biplanar videoradiography system and an optical motion capture system. Results ACLINT female subjects landed with a larger peak vertical GRF (p<0.001) compared to ACLINT male subjects. ACLINT subjects landed with a larger peak vertical GRF (p≤0.036) compared to ACLREC subjects. Regardless of ACL reconstruction status, female subjects underwent less knee flexion angle excursion (p=0.002) and had an increased average rate of anterior tibial translation (0.05±0.01%/millisecond; p=0.037) after contact compared to male subjects. Furthermore, ACLREC subjects had a lower rate of anterior tibial translation compared to ACLINT subjects (0.05±0.01%/millisecond; p=0.035). Finally, no striking differences were observed in other knee motion parameters. Conclusion Women permit a smaller amount of knee flexion angle excursion during a jump-cut maneuver, resulting in a larger peak vertical GRF and increased rate of anterior tibial translation. Notably, ACLREC subjects also perform the jump cut maneuver with lower GRF than ACLINT subjects five years post surgery. This study proposes a causal sequence whereby increased landing stiffness (larger peak vertical GRF combined with less knee flexion angle excursion) leads to an increased rate of anterior tibial translation while performing a jump-cut maneuver. PMID:23190595

  11. EFFECT OF THE GRAFTING SECTION AREA ON ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION SURGERY – HISTOLOGICAL STUDY ON DOGS

    PubMed Central

    Pereira, Ricardo Violante; Müller, Sérgio Swain; Vannini, Rodrigo; Felisbino, Sérgio Luiz; Curcelli, Emilio Carlos; Pereira, Gilberto José Caçdo; de Almeida Silvares, Paulo Roberto

    2015-01-01

    Objective: To correlate the initial grafting section area with the outcomes from anterior cruciate ligament (ACL) reconstruction surgery. Eight dogs underwent operations, divided into two groups according to graft size: Group A, 25% and Group B, 40% of the patellar ligament (PL) width. Methods: After eight months, the dogs were sacrificed for macroscopic and histological analysis on the reconstructed ligaments. Each dog's contralateral knee was used as a control. Results: In both groups, all the reconstructed ligaments were seen to be viable and hypertrophied. The morphology of the PL grafting had changed, which was observed by measuring the crimp and cellularity, and it resembled that of the ACL. Conclusion: The grafting section area did not influence the histological outcomes from ACL reconstruction surgery in dogs. PMID:27047857

  12. Infections in Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Stucken, Charlton; Garras, David N.; Shaner, Julie L.; Cohen, Steven B.

    2013-01-01

    Context: Anterior cruciate ligament (ACL) reconstruction is a safe, common, and effective method of restoring stability to the knee after injury, but evolving techniques of reconstruction carry inherent risk. Infection after ACL reconstruction, while rare, carries a high morbidity, potentially resulting in a poor clinical outcome. Evidence Acquisition: Data were obtained from previously published peer-reviewed literature through a search of the entire PubMed database (up to December 2012) as well as from textbook chapters. Results: Treatment with culture-specific antibiotics and debridement with graft retention is recommended as initial treatment, but with persistent infection, consideration should be given to graft removal. Graft type likely has no effect on infection rates. Conclusion: The early diagnosis of infection and appropriate treatment are necessary to avoid the complications of articular cartilage damage and arthrofibrosis. PMID:24427432

  13. PERI-INCISIONAL DYSESTHESIA FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION USING CENTRAL THIRD OF PATELLAR TENDON

    PubMed Central

    de Carvalho Júnior, Lúcio Honório; Machado, Soares Luiz Fernando; Gonçalves, Matheus Braga Jacques; Júnior, Paulo Randal Pires; Baumfeld, Daniel Soares; Pereira, Marcelo Lobo; Lessa, Rodrigo Rosa; Costa, Lincoln Paiva; Bisinoto, Henrique Barra

    2015-01-01

    Objective: To evaluate the prevalence and type of dysesthesia around the incision used to obtain the patellar tendon for anterior cruciate ligament (ACL) reconstruction surgery. Methods: Out of a population of 1368 ACL reconstructions using the central third of the patellar tendon, 102 patients (111 knees) were evaluated by means of telephone interview. Results: The mean follow-up was 52 months (ranging from 12 to 88 months). The patients' ages ranged from 16 to 58 years (mean: 34.7 years). There was some degree of peri-incisional dysesthesia in 66 knees (59.46%). In 40.54% of the knees, this condition was not found. In all the cases of dysesthesia, the type encountered was Highet's type II. Conclusion: Peri-incisional dysesthesia following ACL reconstruction using the central third of the patellar tendon is highly prevalent. It affected more than half of the cases in this series. PMID:27026983

  14. High resolution x-ray CMT: Reconstruction methods

    SciTech Connect

    Brown, J.K.

    1997-02-01

    This paper qualitatively discusses the primary characteristics of methods for reconstructing tomographic images from a set of projections. These reconstruction methods can be categorized as either {open_quotes}analytic{close_quotes} or {open_quotes}iterative{close_quotes} techniques. Analytic algorithms are derived from the formal inversion of equations describing the imaging process, while iterative algorithms incorporate a model of the imaging process and provide a mechanism to iteratively improve image estimates. Analytic reconstruction algorithms are typically computationally more efficient than iterative methods; however, analytic algorithms are available for a relatively limited set of imaging geometries and situations. Thus, the framework of iterative reconstruction methods is better suited for high accuracy, tomographic reconstruction codes.

  15. Long Term Gait Deviations in Anterior Cruciate Ligament Reconstructed Females

    PubMed Central

    Noehren, Brian; Wilson, Hilary; Miller, Casey; Lattermann, Christian

    2015-01-01

    Purpose Little is known of the potential long term gait alterations that occur after an anterior cruciate ligament (ACL) reconstruction. In particular, variables such as impact loading which have been previously associated with joint deterioration have not been studied in walking and running after an ACL reconstruction. The purpose of this study was to define the alterations in impact forces, loading rates, and the accompanying sagittal plane kinematic and kinetic mechanics at the time of impact between the ACL reconstructed group and a healthy control group. Methods 40 females (20 ACL reconstruction, 20 controls) participated in the study. An instrumented gait analysis was performed on all subjects. Between group and limb comparisons were made for initial vertical impact force, loading rate, sagittal plane knee and hip angles as well as moments. Results During walking and running the ACL cohort had significantly greater initial vertical impact force (p=0.002 and p= 0.001), and loading rates (p=0.03 and p= 0.01), as well as a smaller knee extensor moment and hip angle during walking (p=0.000 and p=0.01). There was a trend towards a smaller knee moment and hip angle during running (p=0.08 and p=0.06) as well as a larger hip extensor moment during walking (p=0.06) in the ACL group. No differences were found for hip extensor moment during running, knee angles between groups during walking or running. Lastly, no between limb differences were found for any variable. Conclusion Gait deviations such as elevated impact loading and loading rates do not resolve long term after the individual has resumed previous activity levels and may contribute to the greater risk of early joint degeneration in this population. PMID:23568090

  16. Compressive measurement and feature reconstruction method for autonomous star trackers

    NASA Astrophysics Data System (ADS)

    Yin, Hang; Yan, Ye; Song, Xin; Yang, Yueneng

    2016-12-01

    Compressive sensing (CS) theory provides a framework for signal reconstruction using a sub-Nyquist sampling rate. CS theory enables the reconstruction of a signal that is sparse or compressible from a small set of measurements. The current CS application in optical field mainly focuses on reconstructing the original image using optimization algorithms and conducts data processing in full-dimensional image, which cannot reduce the data processing rate. This study is based on the spatial sparsity of star image and proposes a new compressive measurement and reconstruction method that extracts the star feature from compressive data and directly reconstructs it to the original image for attitude determination. A pixel-based folding model that preserves the star feature and enables feature reconstruction is presented to encode the original pixel location into the superposed space. A feature reconstruction method is then proposed to extract the star centroid by compensating distortions and to decode the centroid without reconstructing the whole image, which reduces the sampling rate and data processing rate at the same time. The statistical results investigate the proportion of star distortion and false matching results, which verifies the correctness of the proposed method. The results also verify the robustness of the proposed method to a great extent and demonstrate that its performance can be improved by sufficient measurement in noise cases. Moreover, the result on real star images significantly ensures the correct star centroid estimation for attitude determination and confirms the feasibility of applying the proposed method in a star tracker.

  17. Reconstruction versus conservative treatment after rupture of the anterior cruciate ligament: cost effectiveness analysis

    PubMed Central

    2011-01-01

    Background The decision whether to treat conservatively or reconstruct surgically a torn anterior cruciate ligament (ACL) is an ongoing subject of debate. The high prevalence and associated public health burden of torn ACL has led to continuous efforts to determine the best therapeutic approach. A critical evaluation of benefits and expenditures of both treatment options as in a cost effectiveness analysis seems well-suited to provide valuable information for treating physicians and healthcare policymakers. Methods A literature review identified four of 7410 searched articles providing sufficient outcome probabilities for the two treatment options for modeling. A transformation key based on the expert opinions of 25 orthopedic surgeons was used to derive utilities from available evidence. The cost data for both treatment strategies were based on average figures compiled by Orthopaedic University Hospital Balgrist and reinforced by Swiss national statistics. A decision tree was constructed to derive the cost-effectiveness of each strategy, which was then tested for robustness using Monte Carlo simulation. Results Decision tree analysis revealed a cost effectiveness of 16,038 USD/0.78 QALY for ACL reconstruction and 15,466 USD/0.66 QALY for conservative treatment, implying an incremental cost effectiveness of 4,890 USD/QALY for ACL reconstruction. Sensitivity analysis of utilities did not change the trend. Conclusion ACL reconstruction for reestablishment of knee stability seems cost effective in the Swiss setting based on currently available evidence. This, however, should be reinforced with randomized controlled trials comparing the two treatment strategies. PMID:22098703

  18. An image reconstruction method (IRBis) for optical/infrared interferometry

    NASA Astrophysics Data System (ADS)

    Hofmann, K.-H.; Weigelt, G.; Schertl, D.

    2014-05-01

    Aims: We present an image reconstruction method for optical/infrared long-baseline interferometry called IRBis (image reconstruction software using the bispectrum). We describe the theory and present applications to computer-simulated interferograms. Methods: The IRBis method can reconstruct an image from measured visibilities and closure phases. The applied optimization routine ASA_CG is based on conjugate gradients. The method allows the user to implement different regularizers, apply residual ratios as an additional metric for goodness-of-fit, and use previous iteration results as a prior to force convergence. Results: We present the theory of the IRBis method and several applications of the method to computer-simulated interferograms. The image reconstruction results show the dependence of the reconstructed image on the noise in the interferograms (e.g., for ten electron read-out noise and 139 to 1219 detected photons per interferogram), the regularization method, the angular resolution, and the reconstruction parameters applied. Furthermore, we present the IRBis reconstructions submitted to the interferometric imaging beauty contest 2012 initiated by the IAU Working Group on Optical/IR Interferometry and describe the performed data processing steps.

  19. How Are We Measuring Patient Satisfaction After Anterior Cruciate Ligament Reconstruction?

    PubMed Central

    Kahlenberg, Cynthia A.; Nwachukwu, Benedict U.; Ferraro, Richard A.; Schairer, William W.; Steinhaus, Michael E.; Allen, Answorth A.

    2016-01-01

    Background: Reconstruction of the anterior cruciate ligament (ACL) is one of the most common orthopaedic operations in the United States. The long-term impact of ACL reconstruction is controversial, however, as longer term data have failed to demonstrate that ACL reconstruction helps alter the natural history of early onset osteoarthritis that occurs after ACL injury. There is significant interest in evaluating the value of ACL reconstruction surgeries. Purpose: To examine the quality of patient satisfaction reporting after ACL reconstruction surgery. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review of the MEDLINE database was performed using the PubMed interface. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines as well as the PRISMA checklist were employed. The initial search yielded 267 studies. The inclusion criteria were: English language, US patient population, clinical outcome study of ACL reconstruction surgery, and reporting of patient satisfaction included in the study. Study quality was assessed using the Newcastle-Ottawa scale. Results: A total of 22 studies met the inclusion criteria. These studies comprised a total of 1984 patients with a mean age of 31.9 years at the time of surgery and a mean follow-up period of 59.3 months. The majority of studies were evidence level 4 (n = 18; 81.8%), had a mean Newcastle-Ottawa scale score of 5.5, and were published before 2006 (n = 17; 77.3%); 5 studies (22.7%) failed to clearly describe their method for determining patient satisfaction. The most commonly used method for assessing satisfaction was a 0 to 10 satisfaction scale (n = 11; 50.0%). Among studies using a 0 to 10 scale, mean satisfaction ranged from 7.4 to 10.0. Patient-reported outcome and objective functional measures for ACL stability and knee function were positively correlated with patient satisfaction. Degenerative knee change was negatively correlated with satisfaction

  20. An alternative method of middle vault reconstruction.

    PubMed

    Gassner, Holger G; Friedman, Oren; Sherris, David A; Kern, Eugene B

    2006-01-01

    Surgery of the nasal valves is a challenging aspect of rhinoplasty surgery. The middle nasal vault assumes an important role in certain aspects of nasal valve collapse. Techniques that address pathologies of the middle vault include the placement of spreader grafts and the butterfly graft. We present an alternative technique of middle vault reconstruction that allows simultaneous repair of nasal valve collapse and creation of a smooth dorsal profile. The surgical technique is described in detail and representative cases are discussed.

  1. Single-Stage Reconstruction of Both Cruciate Ligaments

    PubMed Central

    Andreoli, Mauro; Zicaro, Juan Pablo; Yacuzzi, Carlos; Costa-Paz, Matias

    2017-01-01

    Objectives: Isolated Anterior Cruciate Ligament (ACL) and Posterior Cruciate Ligament (PCL), or central pivot lesions are rare. These are frequently associated with collateral ligaments injuries. The purpose of this retrospective study was to evaluate clinical and functional outcomes of 4 patients with acute ACL and PCL injury who underwent a simultaneous single-stage arthroscopic reconstruction. Methods: The inclusion criteria were patients with isolated ACL and PCL injuries, with a minimum follow-up of 2 years. We evaluated the type of graft used, the surgical technique and postoperative complications. The scales used for clinical evaluation were the Knee Society Score (KSS), IKDC, Lysholm and Tegner. Knee stability was assessed using the KT-1000 arthrometer. Results: Three men and one woman, with an average age of 48 years (45 to 56 years) were evaluated. Three presented a sport injury and one a car accident. Mean follow-up was 8 years. In all patients allograft was used for ligament reconstruction. Average postoperative results were: KSS 74-82, Lysholm 76, IKDC 63 and Tegner 6. KT-1000 arthrometer showed an average difference of 4mm compared to the contralateral knee. One patient underwent reintervention due to meniscal injury. Conclusion: ACL and PCL simultaneous single-stage reconstruction is a really demanding surgery. We achieved good results using allograft for both ligaments reconstruction. No clinical or functional postoperative complications were recorded.

  2. Radiation risk from fluoroscopically-assisted anterior cruciate ligament reconstruction

    PubMed Central

    Chitnavis, JP; Karthikesaligam, A; Macdonald, A; Brown, C

    2010-01-01

    INTRODUCTION Precise tunnel positioning is crucial for success in anterior cruciate ligament (ACL) reconstruction. The use of intra-operative fluoroscopy has been shown to improve the accuracy of tunnel placement. Although radiation exposure is a concern, we lack information on the radiation risk to patients undergoing fluoroscopically-assisted ACL reconstruction with a standard C-arm. The aim of our study was to determine the mean radiation doses received by our patients. PATIENTS AND METHODS Radiation doses were recorded for 18 months between 1 April 2007 and 30 September 2008 for 58 consecutive patients undergoing ACL reconstruction assisted by intra-operative fluoroscopy. Dose area product (DAP) values were used to calculate the entrance skin dose (ESD), an indicator of potential skin damage and the effective dose (ED), an indicator of long-term cancer risk, for each patient. RESULTS The median age of 58 patients included in data analysis was 28 years (range, 14–52 years), of whom 44 were male (76%). The mean ESD during intra-operative fluoroscopy was 0.0015 ± 0.0029 Gy. The mean ED was 0.001 ± 0.002 mSv. No results exceeded the threshold of 2 Gy for skin damage, and the life-time risk of developing new cancer due to intra-operative fluoroscopy is less than 0.0001%. CONCLUSIONS Radiation doses administered during fluoroscopically-assisted ACL reconstruction were safe and do not represent a contra-indication to the procedure. PMID:20501019

  3. Association Between Lateral Posterior Tibial Slope, Body Mass Index, and ACL Injury Risk

    PubMed Central

    Bojicic, Katherine M.; Beaulieu, Mélanie L.; Imaizumi Krieger, Daniel Y.; Ashton-Miller, James A.; Wojtys, Edward M.

    2017-01-01

    Background: While body mass index (BMI), a modifiable parameter, and knee morphology, a nonmodifiable parameter, have been identified as risk factors for anterior cruciate ligament (ACL) rupture, the interaction between them remains unknown. An understanding of this interaction is important because greater compressive axial force (perhaps due to greater BMI) applied to a knee that is already at an increased risk because of its geometry, such as a steep lateral posterior tibial slope, could further increase the probability of ACL injury. Purpose: To quantify the relationship between BMI and select knee morphological parameters as potential risk factors for ACL injury. Study Design: Case-control study; Level of evidence, 3. Methods: Sagittal knee magnetic resonance imaging (MRI) files from 76 ACL-injured and 42 uninjured subjects were gathered from the University of Michigan Health System’s archive. The posterior tibial slope (PTS), middle cartilage slope (MCS), posterior meniscus height (PMH), and posterior meniscus bone angle (MBA) in the lateral compartment were measured using MRI. BMI was calculated from demographic data. The association between the knee structural factors, BMI, and ACL injury risk was explored using univariate and multivariate logistic regression. Results: PTS (P = .043) and MCS (P = .037) significantly predicted ACL injury risk. As PTS and MCS increased by 1°, odds of sustaining an ACL injury increased by 12% and 13%, respectively. The multivariate logistic regression analysis, which included PTS, BMI centered around the mean (cBMI), and their interaction, showed that this interaction predicted the odds of ACL rupture (P = .050; odds ratio, 1.03). For every 1-unit increase in BMI from the average that is combined with a 1° increase in PTS, the odds of an ACL tear increased by 15%. Conclusion: An increase in BMI was associated with increased risk of ACL tear in the presence of increased lateral posterior tibial slope. Larger values of PTS or

  4. Optimization and Comparison of Different Digital Mammographic Tomosynthesis Reconstruction Methods

    DTIC Science & Technology

    2007-04-01

    likelihood iterative algorithm (MLEM) by Wu et al. [4,5], tuned-aperture computed tomography (TACT) reconstruction methods developed by Webber and...A. Karellas, S. Vedantham, S. J. Glick, C. J. D’Orsi, S. P. Baker, and R. L. Webber , “Comparison of tomosynthesis methods used with digital...L. Webber , “Evaluation of linear and nonlinear tomosynthetic reconstruction methods in digital mammography,” Acad. Radiol. 8, 219-224 (2001). 8. L

  5. An analytic reconstruction method for PET based on cubic splines

    NASA Astrophysics Data System (ADS)

    Kastis, George A.; Kyriakopoulou, Dimitra; Fokas, Athanasios S.

    2014-03-01

    PET imaging is an important nuclear medicine modality that measures in vivo distribution of imaging agents labeled with positron-emitting radionuclides. Image reconstruction is an essential component in tomographic medical imaging. In this study, we present the mathematical formulation and an improved numerical implementation of an analytic, 2D, reconstruction method called SRT, Spline Reconstruction Technique. This technique is based on the numerical evaluation of the Hilbert transform of the sinogram via an approximation in terms of 'custom made' cubic splines. It also imposes sinogram thresholding which restricts reconstruction only within object pixels. Furthermore, by utilizing certain symmetries it achieves a reconstruction time similar to that of FBP. We have implemented SRT in the software library called STIR and have evaluated this method using simulated PET data. We present reconstructed images from several phantoms. Sinograms have been generated at various Poison noise levels and 20 realizations of noise have been created at each level. In addition to visual comparisons of the reconstructed images, the contrast has been determined as a function of noise level. Further analysis includes the creation of line profiles when necessary, to determine resolution. Numerical simulations suggest that the SRT algorithm produces fast and accurate reconstructions at realistic noise levels. The contrast is over 95% in all phantoms examined and is independent of noise level.

  6. An ambulatory method of identifying anterior cruciate ligament reconstructed gait patterns.

    PubMed

    Patterson, Matthew R; Delahunt, Eamonn; Sweeney, Kevin T; Caulfield, Brian

    2014-01-07

    The use of inertial sensors to characterize pathological gait has traditionally been based on the calculation of temporal and spatial gait variables from inertial sensor data. This approach has proved successful in the identification of gait deviations in populations where substantial differences from normal gait patterns exist; such as in Parkinsonian gait. However, it is not currently clear if this approach could identify more subtle gait deviations, such as those associated with musculoskeletal injury. This study investigates whether additional analysis of inertial sensor data, based on quantification of gyroscope features of interest, would provide further discriminant capability in this regard. The tested cohort consisted of a group of anterior cruciate ligament reconstructed (ACL-R) females and a group of non-injured female controls, each performed ten walking trials. Gait performance was measured simultaneously using inertial sensors and an optoelectronic marker based system. The ACL-R group displayed kinematic and kinetic deviations from the control group, but no temporal or spatial deviations. This study demonstrates that quantification of gyroscope features can successfully identify changes associated with ACL-R gait, which was not possible using spatial or temporal variables. This finding may also have a role in other clinical applications where small gait deviations exist.

  7. Anatomically-aided PET reconstruction using the kernel method

    NASA Astrophysics Data System (ADS)

    Hutchcroft, Will; Wang, Guobao; Chen, Kevin T.; Catana, Ciprian; Qi, Jinyi

    2016-09-01

    This paper extends the kernel method that was proposed previously for dynamic PET reconstruction, to incorporate anatomical side information into the PET reconstruction model. In contrast to existing methods that incorporate anatomical information using a penalized likelihood framework, the proposed method incorporates this information in the simpler maximum likelihood (ML) formulation and is amenable to ordered subsets. The new method also does not require any segmentation of the anatomical image to obtain edge information. We compare the kernel method with the Bowsher method for anatomically-aided PET image reconstruction through a simulated data set. Computer simulations demonstrate that the kernel method offers advantages over the Bowsher method in region of interest quantification. Additionally the kernel method is applied to a 3D patient data set. The kernel method results in reduced noise at a matched contrast level compared with the conventional ML expectation maximization algorithm.

  8. Electrospinning polymer blends for biomimetic scaffolds for ACL tissue engineering

    NASA Astrophysics Data System (ADS)

    Garcia, Vanessa Lizeth

    The anterior cruciate ligament (ACL) rupture is one of the most common knee injuries. Current ACL reconstructive strategies consist of using an autograft or an allograft to replace the ligament. However, limitations have led researchers to create tissue engineered grafts, known as scaffolds, through electrospinning. Scaffolds made of natural and synthetic polymer blends have the potential to promote cell adhesion while having strong mechanical properties. However, enzymes found in the knee are known to degrade tissues and affect the healing of intra-articular injuries. Results suggest that the natural polymers used in this study modify the thermal properties and tensile strength of the synthetic polymers when blended. Scanning electron microscopy display bead-free and enzyme biodegradability of the fibers. Raman spectroscopy confirms the presence of the natural and synthetic polymers in the scaffolds while, amino acid analysis present the types of amino acids and their concentrations found in the natural polymers.

  9. Unilateral Stance Strategies of Athletes With ACL Deficiency

    PubMed Central

    Di Stasi, Stephanie L.; Hartigan, Erin H.; Snyder-Mackler, Lynn

    2013-01-01

    Aberrant movement strategies are characteristic of ACL-deficient athletes with recurrent knee instability (non-copers), and may instigate premature or accelerate joint degradation. Biomechanical evaluation of kinematic changes over time may elucidate noncopers’ responses to neuromuscular intervention and ACL reconstruction (ACLR). Forty noncopers were randomized into a perturbation group or a strength training only group. We evaluated the effects of perturbation training, and then gender on knee angle and tibial position during a unilateral standing task before and after ACLR. No statistically significant interactions were found. Before surgery, the strength training only group demonstrated knee angle asymmetry, but 6 months after ACLR, both groups presented with similar knee flexion between limbs. Aberrant and asymmetrical tibial position was found only in females following injury and ACLR. Neither treatment group showed distinct unilateral standing strategies following intervention; however, males and female noncopers appear to respond uniquely to physical therapy and surgery. PMID:22983931

  10. Reconstruction of the anterior cruciate ligament in skeletally immature patients: an individualized approach☆☆☆

    PubMed Central

    Lopes Júnior, Osmar Valadão; Saggin, Paulo Renato; Matos do Nascimento, Gilberto; Kuhn, André; Saggin, José; Inácio, André Manoel

    2014-01-01

    Objective to evaluate a series of skeletally immature patients who underwent three surgical techniques for anterior cruciate ligament (ACL) reconstruction according to each patient's growth potential. Methods a series of 23 skeletally immature patients who underwent ACL reconstruction surgery at ages ranging from 7 to 15 years was evaluated prospectively. The surgical technique was individualized according to the Tanner sexual maturity score. The surgical techniques used were transphyseal reconstruction, partial transphyseal reconstruction and extraphyseal reconstruction. Four patients underwent the extraphyseal technique, seven the partial transphyseal technique and twelve the full transphyseal technique, on the ACL. The postoperative evaluation was based on the Lysholm score, clinical analysis on the knee and the presence of angular deformity or dysmetria of the lower limb. Results the mean Lysholm score was 96.34 (±2.53). None of the patients presented differences in length and/or clinical or radiographic misalignment abnormality of the lower limbs. Conclusion ACL reconstruction using flexor tendon grafts in skeletally immature patients provided satisfactory functional results. Use of individualized surgical techniques according to growth potential did not give rise to physeal lesions capable of causing length discrepancies or misalignments of the lower limbs, even in patients with high growth potential. PMID:26229809

  11. Association Between Meniscal and Chondral Lesions and Timing of Anterior Cruciate Ligament Reconstruction

    PubMed Central

    de Campos, Gustavo Constantino; Nery, Wilton; Teixeira, Paulo Eduardo Portes; Araujo, Paulo Henrique; Alves, Wilson de Mello

    2016-01-01

    Background: Rupture of the anterior cruciate ligament (ACL) is a common sports injury and is known to be associated with an increased risk of knee osteoarthritis. Several studies have indicated that the risk of additional injuries to the menisci and articular cartilage increases with delays in the treatment of ACL tears. However, no consensus has been reached regarding the ideal timing for ACL reconstruction in terms of preventing secondary lesions. Purpose: To determine how the time elapsed between an ACL lesion and its reconstruction affects the incidence of meniscal and chondral lesions. Study Design: Case series; Level of evidence, 4. Methods: Medical records of 764 patients who underwent primary ACL reconstruction were reviewed. Data from arthroscopic findings that included information about meniscal lesions and full-thickness articular cartilage lesions at the time of surgery were collected. The association between time elapsed between ACL lesion and reconstruction surgery and incidence of articular cartilage and meniscal lesions was analyzed by chi-square or Fisher exact test. The risk of secondary lesion was calculated by odds ratios (ORs) obtained from simple logistic regression analysis. Results: A positive correlation was observed between time after injury and the presence of any articular lesions (P = .003), cartilage lesions (P = .01), and medial meniscus lesions (P < .001). When analyzing the risk of secondary lesion relative to the reference period (<2 months), it was observed that the odds of finding any articular injury at the time of ACL reconstruction increased when the time from ACL injury to surgery was between 12 and 24 months (OR = 2.62) and >24 months (OR = 5.88). Furthermore, the odds of lesions on the medial meniscus increased when the timing between injury and surgery was 6 to 12 months (OR = 2.71) and continued to increase when the timing was 12 to 24 months (OR = 3.78) and >24 months (OR = 9.07). Conclusion: Associated articular lesions

  12. A novel method of anterior lumbosacral cage reconstruction.

    PubMed

    Mathios, Dimitrios; Kaloostian, Paul Edward; Bydon, Ali; Sciubba, Daniel M; Wolinsky, Jean Paul; Gokaslan, Ziya L; Witham, Timothy F

    2014-02-01

    Reconstruction of the lumbosacral junction is a considerable challenge for spinal surgeons due to the unique anatomical constraints of this region as well as the vectors of force that are applied focally in this area. The standard cages, both expandable and nonexpendable, often fail to reconstitute the appropriate anatomical alignment of the lumbosacral junction. This inadequate reconstruction may predispose the patient to continued back pain and neurological symptoms as well as possible pseudarthrosis and instrumentation failure. The authors describe their preoperative planning and the technical characteristics of their novel reconstruction technique at the lumbosacral junction using a cage with adjustable caps. Based precisely on preoperative measurements that maintain the appropriate Cobb angle, they performed reconstruction of the lumbosacral junction in a series of 3 patients. All 3 patients had excellent installation of the cages used for reconstruction. Postoperative CT scans were used to radiographically confirm the appropriate reconstruction of the lumbosacral junction. All patients had a significant reduction in pain, had neurological improvement, and experienced no instrumentation failure at the time of latest follow-up. Taking into account the inherent morphology of the lumbosacral junction and carefully planning the technical characteristics of the cage installation preoperatively and intraoperatively, the authors achieved favorable clinical and radiographic outcomes in all 3 cases. Based on this small case series, this technique for reconstruction of the lumbosacral junction appears to be a safe and appropriate method of reconstruction of the anterior spinal column in this technically challenging region of the spine.

  13. Reconstruction methods for phase-contrast tomography

    SciTech Connect

    Raven, C.

    1997-02-01

    Phase contrast imaging with coherent x-rays can be distinguished in outline imaging and holography, depending on the wavelength {lambda}, the object size d and the object-to-detector distance r. When r << d{sup 2}{lambda}, phase contrast occurs only in regions where the refractive index fastly changes, i.e. at interfaces and edges in the sample. With increasing object-to-detector distance we come in the area of holographic imaging. The image contrast outside the shadow region of the object is due to interference of the direct, undiffracted beam and a beam diffracted by the object, or, in terms of holography, the interference of a reference wave with the object wave. Both, outline imaging and holography, offer the possibility to obtain three dimensional information of the sample in conjunction with a tomographic technique. But the data treatment and the kind of information one can obtain from the reconstruction is different.

  14. Anterior cruciate ligament- specialized post-operative return-to-sports (ACL-SPORTS) training: a randomized control trial

    PubMed Central

    2013-01-01

    Background Anterior cruciate ligament reconstruction (ACLR) is standard practice for athletes that wish to return to high-level activities; however functional outcomes after ACLR are poor. Quadriceps strength weakness, abnormal movement patterns and below normal knee function is reported in the months and years after ACLR. Second ACL injuries are common with even worse outcomes than primary ACLR. Modifiable limb-to-limb asymmetries have been identified in individuals who re-injure after primary ACLR, suggesting a neuromuscular training program is needed to improve post-operative outcomes. Pre-operative perturbation training, a neuromuscular training program, has been successful at improving limb symmetry prior to surgery, though benefits are not lasting after surgery. Implementing perturbation training after surgery may be successful in addressing post-operative deficits that contribute to poor functional outcomes and second ACL injury risk. Methods/Design 80 athletes that have undergone a unilateral ACLR and wish to return to level 1 or 2 activities will be recruited for this study and randomized to one of two treatment groups. A standard care group will receive prevention exercises, quadriceps strengthening and agility exercises, while the perturbation group will receive the same exercise program with the addition of perturbation training. The primary outcomes measures will include gait biomechanics, clinical and functional measures, and knee joint loading. Return to sport rates, return to pre-injury level of activity rates, and second injury rates will be secondary measures. Discussion The results of this ACL-Specialized Post-Operative Return To Sports (ACL-SPORTS) Training program will help clinicians to better determine an effective post-operative treatment program that will improve modifiable impairments that influence outcomes after ACLR. Trial registration Randomized Control Trial NIH 5R01AR048212-07. ClinicalTrials.gov: NCT01773317 PMID:23522373

  15. Effect of ACL graft material on joint forces during a simulated in vivo motion in the porcine knee: examining force during the initial cycles.

    PubMed

    Boguszewski, Daniel V; Wagner, Christopher T; Butler, David L; Shearn, Jason T

    2014-11-01

    This study compared three-dimensional forces in knees containing anterior cruciate ligament (ACL) graft materials versus the native porcine ACL. A six-degree-of-freedom (DOF) robot simulated gait while recording the joint forces and moments. Knees were subjected to 10 cycles of simulated gait in intact, ACL-deficient, and ACL-reconstructed knee states to examine time zero biomechanical performance. Reconstruction was performed using bone-patellar tendon-bone allograft (BPTB), reconstructive porcine tissue matrix (RTM), and an RTM-polymer hybrid (Hybrid). Forces and moments were examined about anatomic DOFs throughout the gait cycle and at three key points during gait: heel strike (HS), mid stance (MS), toe off (TO). Compared to native ACL, each graft restored antero-posterior (A-P) forces throughout gait. However, all failed to mimic normal joint forces in other DOFs. For example, each reconstructed knee showed greater compressive forces at HS and TO compared to the native ACL knee. Overall, the Hybrid graft restored more of the native ACL forces following reconstruction than did BPTB, while RTM grafts were the least successful. If early onset osteoarthritis is in part caused by altered knee kinematics, then understanding how reconstruction materials restore critical force generation during gait is an essential step in improving a patient's long-term prognosis.

  16. Yeast Ancestral Genome Reconstructions: The Possibilities of Computational Methods

    NASA Astrophysics Data System (ADS)

    Tannier, Eric

    In 2006, a debate has risen on the question of the efficiency of bioinformatics methods to reconstruct mammalian ancestral genomes. Three years later, Gordon et al. (PLoS Genetics, 5(5), 2009) chose not to use automatic methods to build up the genome of a 100 million year old Saccharomyces cerevisiae ancestor. Their manually constructed ancestor provides a reference genome to test whether automatic methods are indeed unable to approach confident reconstructions. Adapting several methodological frameworks to the same yeast gene order data, I discuss the possibilities, differences and similarities of the available algorithms for ancestral genome reconstructions. The methods can be classified into two types: local and global. Studying the properties of both helps to clarify what we can expect from their usage. Both methods propose contiguous ancestral regions that come very close (> 95% identity) to the manually predicted ancestral yeast chromosomes, with a good coverage of the extant genomes.

  17. A novel electron density reconstruction method for asymmetrical toroidal plasmas

    SciTech Connect

    Shi, N.; Ohshima, S.; Minami, T.; Nagasaki, K.; Yamamoto, S.; Mizuuchi, T.; Okada, H.; Kado, S.; Kobayashi, S.; Konoshima, S.; Sano, F.; Tanaka, K.; Ohtani, Y.; Zang, L.; Kenmochi, N.

    2014-05-15

    A novel reconstruction method is developed for acquiring the electron density profile from multi-channel interferometric measurements of strongly asymmetrical toroidal plasmas. It is based on a regularization technique, and a generalized cross-validation function is used to optimize the regularization parameter with the aid of singular value decomposition. The feasibility of method could be testified by simulated measurements based on a magnetic configuration of the flexible helical-axis heliotron device, Heliotron J, which has an asymmetrical poloidal cross section. And the successful reconstruction makes possible to construct a multi-channel Far-infrared laser interferometry on this device. The advantages of this method are demonstrated by comparison with a conventional method. The factors which may affect the accuracy of the results are investigated, and an error analysis is carried out. Based on the obtained results, the proposed method is highly promising for accurately reconstructing the electron density in the asymmetrical toroidal plasma.

  18. Revision Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Wilde, Jeffrey; Bedi, Asheesh; Altchek, David W.

    2014-01-01

    Context: Reconstruction of the anterior cruciate ligament (ACL) is one of the most common surgical procedures, with more than 200,000 ACL tears occurring annually. Although primary ACL reconstruction is a successful operation, success rates still range from 75% to 97%. Consequently, several thousand revision ACL reconstructions are performed annually and are unfortunately associated with inferior clinical outcomes when compared with primary reconstructions. Evidence Acquisition: Data were obtained from peer-reviewed literature through a search of the PubMed database (1988-2013) as well as from textbook chapters and surgical technique papers. Study Design: Clinical review. Level of Evidence: Level 4. Results: The clinical outcomes after revision ACL reconstruction are largely based on level IV case series. Much of the existing literature is heterogenous with regard to patient populations, primary and revision surgical techniques, concomitant ligamentous injuries, and additional procedures performed at the time of the revision, which limits generalizability. Nevertheless, there is a general consensus that the outcomes for revision ACL reconstruction are inferior to primary reconstruction. Conclusion: Excellent results can be achieved with regard to graft stability, return to play, and functional knee instability but are generally inferior to primary ACL reconstruction. A staged approach with autograft reconstruction is recommended in any circumstance in which a single-stage approach results in suboptimal graft selection, tunnel position, graft fixation, or biological milieu for tendon-bone healing. Strength-of-Recommendation Taxonomy (SORT): Good results may still be achieved with regard to graft stability, return to play, and functional knee instability, but results are generally inferior to primary ACL reconstruction: Level B. PMID:25364483

  19. Assessing the Accuracy of Ancestral Protein Reconstruction Methods

    PubMed Central

    Williams, Paul D; Pollock, David D; Blackburne, Benjamin P; Goldstein, Richard A

    2006-01-01

    The phylogenetic inference of ancestral protein sequences is a powerful technique for the study of molecular evolution, but any conclusions drawn from such studies are only as good as the accuracy of the reconstruction method. Every inference method leads to errors in the ancestral protein sequence, resulting in potentially misleading estimates of the ancestral protein's properties. To assess the accuracy of ancestral protein reconstruction methods, we performed computational population evolution simulations featuring near-neutral evolution under purifying selection, speciation, and divergence using an off-lattice protein model where fitness depends on the ability to be stable in a specified target structure. We were thus able to compare the thermodynamic properties of the true ancestral sequences with the properties of “ancestral sequences” inferred by maximum parsimony, maximum likelihood, and Bayesian methods. Surprisingly, we found that methods such as maximum parsimony and maximum likelihood that reconstruct a “best guess” amino acid at each position overestimate thermostability, while a Bayesian method that sometimes chooses less-probable residues from the posterior probability distribution does not. Maximum likelihood and maximum parsimony apparently tend to eliminate variants at a position that are slightly detrimental to structural stability simply because such detrimental variants are less frequent. Other properties of ancestral proteins might be similarly overestimated. This suggests that ancestral reconstruction studies require greater care to come to credible conclusions regarding functional evolution. Inferred functional patterns that mimic reconstruction bias should be reevaluated. PMID:16789817

  20. Anatomical reference point for harvesting a flexor graft during arthroscopic reconstruction of the anterior cruciate ligament☆

    PubMed Central

    de Lima Lopes, Clécio; Arantes, Gabriel; de Oliveira, Rodrigo Victor Lapenda; Pinto, Dilamar Moreira; Gonçalves, Marcelo Carvalho Krause; Gonçalves, Romeu Carvalho Krause

    2015-01-01

    Objectives To evaluate the prevalence of a vascular network adjacent to the insertion of the pes anserinus, so that it could be used as an anatomical reference point to facilitate harvesting flexor grafts for arthroscopic reconstruction of the anterior cruciate ligament (ACL). Methods Thirty patients with ACL tears who were going to undergo ACL reconstruction using the tendons of the semitendinosus and gracilis muscles as grafts were selected randomly. During the harvesting of these tendons, the presence or absence of this anatomical reference point was noted. Results All the patients presented a vascular network of greater or lesser diameter. Conclusion The vascular network seems to be a good reference point during harvesting of the tendons of the semitendinosus and gracilis muscles, for facilitating graft harvesting. PMID:26229911

  1. Anterior Cruciate Ligament Reconstruction Using a Combination of Autograft and Allograft Tendon

    PubMed Central

    Darnley, James E.; Léger-St-Jean, Benjamin; Pedroza, Angela D.; Flanigan, David C.; Kaeding, Christopher C.; Magnussen, Robert A.

    2016-01-01

    Background: Anterior cruciate ligament (ACL) reconstruction with hamstring autografts less than 8.5 mm in diameter is associated with worse patient-reported outcome scores and increased risk of revision surgery compared with reconstructions performed with larger grafts. One proposed solution to small autograft harvest is to create a hybrid graft by augmenting autografts with allograft tissue to increase graft diameter. Purpose: To compare hybrid autograft/allograft ACL reconstruction to autograft ACL reconstruction, specifically analyzing the patient-reported outcome scores and the risk of revision surgery at 2 years postoperative. Study Design: Cohort study; Level of evidence, 3. Methods: From the years 2002 to 2009, a total of 34 patients were identified from a prospectively collected database as having undergone hybrid ACL reconstruction. Twenty-seven of 34 (79.4%) patients had a 2-year follow-up. These 27 patients were matched by age (within 1 year) and sex to 27 patients who underwent hamstring autograft ACL reconstruction during the same period. At the 2-year mark, revision surgery risk and patient-reported outcome scores were compared between the 2 groups. Results: The mean age for the hybrid and matched groups (±SD) was 20.9 ± 7.0 years. Both the hybrid and control groups had 17 males and 10 females. There was no significant difference in preoperative patient-reported outcome scores, meniscus tears, or cartilage lesions between the 2 groups. Graft size was larger in the hybrid group (9.5 ± 0.6 mm) than in the autograft group (8.4 ± 0.9 mm) (P < .001). At 2 years postoperative, patient-reported outcome scores were similar between the hybrid and autograft groups. Revision surgery was required in 5 (18.5%) patients who underwent hybrid reconstruction compared with 2 (7.4%) of those who underwent autograft reconstruction (P = .26). Conclusion: Patients who undergo ACL reconstruction with hybrid hamstring grafts and hamstring autografts report similar

  2. A Comparison of Methods for Ocean Reconstruction from Sparse Observations

    NASA Astrophysics Data System (ADS)

    Streletz, G. J.; Kronenberger, M.; Weber, C.; Gebbie, G.; Hagen, H.; Garth, C.; Hamann, B.; Kreylos, O.; Kellogg, L. H.; Spero, H. J.

    2014-12-01

    We present a comparison of two methods for developing reconstructions of oceanic scalar property fields from sparse scattered observations. Observed data from deep sea core samples provide valuable information regarding the properties of oceans in the past. However, because the locations of sample sites are distributed on the ocean floor in a sparse and irregular manner, developing a global ocean reconstruction is a difficult task. Our methods include a flow-based and a moving least squares -based approximation method. The flow-based method augments the process of interpolating or approximating scattered scalar data by incorporating known flow information. The scheme exploits this additional knowledge to define a non-Euclidean distance measure between points in the spatial domain. This distance measure is used to create a reconstruction of the desired scalar field on the spatial domain. The resulting reconstruction thus incorporates information from both the scattered samples and the known flow field. The second method does not assume a known flow field, but rather works solely with the observed scattered samples. It is based on a modification of the moving least squares approach, a weighted least squares approximation method that blends local approximations into a global result. The modifications target the selection of data used for these local approximations and the construction of the weighting function. The definition of distance used in the weighting function is crucial for this method, so we use a machine learning approach to determine a set of near-optimal parameters for the weighting. We have implemented both of the reconstruction methods and have tested them using several sparse oceanographic datasets. Based upon these studies, we discuss the advantages and disadvantages of each method and suggest possible ways to combine aspects of both methods in order to achieve an overall high-quality reconstruction.

  3. The frequency split method for helical cone-beam reconstruction.

    PubMed

    Shechter, G; Köhler, Th; Altman, A; Proksa, R

    2004-08-01

    A new approximate method for the utilization of redundant data in helical cone-beam CT is presented. It is based on the observation that the original WEDGE method provides excellent image quality if only little more than 180 degrees data are used for back-projection, and that significant low-frequency artifacts appear if a larger amount of redundant data are used. This degradation is compensated by the frequency split method: The low-frequency part of the image is reconstructed using little more than 180 degrees of data, while the high frequency part is reconstructed using all data. The resulting algorithm shows no cone-beam artifacts in a simulation of a 64-row scanner. It is further shown that the frequency split method hardly degrades the signal-to-noise ratio of the reconstructed images and that it behaves robustly in the presence of motion.

  4. ACLS.

    PubMed

    Handley, A J

    2001-09-01

    It must be emphasised that the published International Guidelines 2000 contain an in-depth presentation of the scientific evidence behind advanced life support. The exact interpretation of this evidence, and the algorithms adopted by a national resuscitation council will depend upon various factors such as local interpretation of the evidence, local practice and availability of drugs. The ERC is publishing its own summaries of the guideline changes and the sequences of action for both BLS and ALS and these papers are recommended for further reading.

  5. Knee Contact Force Asymmetries in Patients Who Failed Return-to-Sport Readiness Criteria 6 Months After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Gardinier, Emily S.; Di Stasi, Stephanie; Manal, Kurt; Buchanan, Thomas S.; Snyder-Mackler, Lynn

    2015-01-01

    Background After anterior cruciate ligament (ACL) injury, contact forces are decreased in the injured knee when compared with the uninjured knee. The persistence of contact force asymmetries after ACL reconstruction may increase the risk of reinjury and may play an important role in the development of knee osteoarthritis in these patients. Functional performance may also be useful in identifying patients who demonstrate potentially harmful joint contact force asymmetries after ACL reconstruction. Hypothesis Knee joint contact force asymmetries would be present during gait after ACL reconstruction, and performance on a specific set of validated return-to-sport (RTS) readiness criteria would discriminate between those who demonstrated contact force asymmetries and those who did not. Study Design Descriptive laboratory study. Methods A total of 29 patients with ACL ruptures participated in gait analysis and RTS readiness testing 6 months after reconstruction. Muscle and joint contact forces were estimated using an electromyography (EMG)–driven musculoskeletal model of the knee. The magnitude of typical limb asymmetry in uninjured controls was used to define limits of meaningful limb asymmetry in patients after ACL reconstruction. The RTS testing included isometric quadriceps strength testing, 4 unilateral hop tests, and 2 self-report questionnaires. Paired t tests were used to assess limb symmetry for peak medial and tibiofemoral contact forces in all patients, and a mixed-design analysis of variance was used to analyze the effect of passing or failing RTS testing on contact force asymmetry. Results Among all patients, neither statistically significant nor meaningful contact force asymmetries were identified. However, patients who failed RTS testing exhibited meaningful contact force asymmetries, with tibiofemoral contact force being significantly lower for the involved knee. Conversely, patients who passed RTS testing exhibited neither significant nor meaningful

  6. Matrix-based image reconstruction methods for tomography

    SciTech Connect

    Llacer, J.; Meng, J.D.

    1984-10-01

    Matrix methods of image reconstruction have not been used, in general, because of the large size of practical matrices, ill condition upon inversion and the success of Fourier-based techniques. An exception is the work that has been done at the Lawrence Berkeley Laboratory for imaging with accelerated radioactive ions. An extension of that work into more general imaging problems shows that, with a correct formulation of the problem, positron tomography with ring geometries results in well behaved matrices which can be used for image reconstruction with no distortion of the point response in the field of view and flexibility in the design of the instrument. Maximum Likelihood Estimator methods of reconstruction, which use the system matrices tailored to specific instruments and do not need matrix inversion, are shown to result in good preliminary images. A parallel processing computer structure based on multiple inexpensive microprocessors is proposed as a system to implement the matrix-MLE methods. 14 references, 7 figures.

  7. Fast alternating projection methods for constrained tomographic reconstruction.

    PubMed

    Liu, Li; Han, Yongxin; Jin, Mingwu

    2017-01-01

    The alternating projection algorithms are easy to implement and effective for large-scale complex optimization problems, such as constrained reconstruction of X-ray computed tomography (CT). A typical method is to use projection onto convex sets (POCS) for data fidelity, nonnegative constraints combined with total variation (TV) minimization (so called TV-POCS) for sparse-view CT reconstruction. However, this type of method relies on empirically selected parameters for satisfactory reconstruction and is generally slow and lack of convergence analysis. In this work, we use a convex feasibility set approach to address the problems associated with TV-POCS and propose a framework using full sequential alternating projections or POCS (FS-POCS) to find the solution in the intersection of convex constraints of bounded TV function, bounded data fidelity error and non-negativity. The rationale behind FS-POCS is that the mathematically optimal solution of the constrained objective function may not be the physically optimal solution. The breakdown of constrained reconstruction into an intersection of several feasible sets can lead to faster convergence and better quantification of reconstruction parameters in a physical meaningful way than that in an empirical way of trial-and-error. In addition, for large-scale optimization problems, first order methods are usually used. Not only is the condition for convergence of gradient-based methods derived, but also a primal-dual hybrid gradient (PDHG) method is used for fast convergence of bounded TV. The newly proposed FS-POCS is evaluated and compared with TV-POCS and another convex feasibility projection method (CPTV) using both digital phantom and pseudo-real CT data to show its superior performance on reconstruction speed, image quality and quantification.

  8. MR Image Reconstruction Using Block Matching and Adaptive Kernel Methods

    PubMed Central

    Schmidt, Johannes F. M.; Santelli, Claudio; Kozerke, Sebastian

    2016-01-01

    An approach to Magnetic Resonance (MR) image reconstruction from undersampled data is proposed. Undersampling artifacts are removed using an iterative thresholding algorithm applied to nonlinearly transformed image block arrays. Each block array is transformed using kernel principal component analysis where the contribution of each image block to the transform depends in a nonlinear fashion on the distance to other image blocks. Elimination of undersampling artifacts is achieved by conventional principal component analysis in the nonlinear transform domain, projection onto the main components and back-mapping into the image domain. Iterative image reconstruction is performed by interleaving the proposed undersampling artifact removal step and gradient updates enforcing consistency with acquired k-space data. The algorithm is evaluated using retrospectively undersampled MR cardiac cine data and compared to k-t SPARSE-SENSE, block matching with spatial Fourier filtering and k-t ℓ1-SPIRiT reconstruction. Evaluation of image quality and root-mean-squared-error (RMSE) reveal improved image reconstruction for up to 8-fold undersampled data with the proposed approach relative to k-t SPARSE-SENSE, block matching with spatial Fourier filtering and k-t ℓ1-SPIRiT. In conclusion, block matching and kernel methods can be used for effective removal of undersampling artifacts in MR image reconstruction and outperform methods using standard compressed sensing and ℓ1-regularized parallel imaging methods. PMID:27116675

  9. A reconstructed discontinuous Galerkin method for magnetohydrodynamics on arbitrary grids

    NASA Astrophysics Data System (ADS)

    Karami Halashi, Behrouz; Luo, Hong

    2016-12-01

    A reconstructed discontinuous Galerkin (rDG) method, designed not only to enhance the accuracy of DG methods but also to ensure the nonlinear stability of the rDG method, is developed for solving the Magnetohydrodynamics (MHD) equations on arbitrary grids. In this rDG(P1P2) method, a quadratic polynomial solution (P2) is first obtained using a Hermite Weighted Essentially Non-oscillatory (WENO) reconstruction from the underlying linear polynomial (P1) discontinuous Galerkin solution to ensure linear stability of the rDG method and to improves efficiency of the underlying DG method. By taking advantage of handily available and yet invaluable information, namely the first derivatives in the DG formulation, the stencils used in reconstruction involve only Von Neumann neighborhood (adjacent face-neighboring cells) and thus are compact. The first derivatives of the quadratic polynomial solution are then reconstructed using a WENO reconstruction in order to eliminate spurious oscillations in the vicinity of strong discontinuities, thus ensuring the nonlinear stability of the rDG method. The HLLD Riemann solver introduced in the literature for one-dimensional MHD problems is adopted in normal direction to compute numerical fluxes. The divergence free constraint is satisfied using the Locally Divergence Free (LDF) approach. The developed rDG method is used to compute a variety of 2D and 3D MHD problems on arbitrary grids to demonstrate its accuracy, robustness, and non-oscillatory property. Our numerical experiments indicate that the rDG(P1P2) method is able to capture shock waves sharply essentially without any spurious oscillations, and achieve the designed third-order of accuracy: one order accuracy higher than the underlying DG method.

  10. Tomographic fluorescence reconstruction by a spectral projected gradient pursuit method

    NASA Astrophysics Data System (ADS)

    Ye, Jinzuo; An, Yu; Mao, Yamin; Jiang, Shixin; Yang, Xin; Chi, Chongwei; Tian, Jie

    2015-03-01

    In vivo fluorescence molecular imaging (FMI) has played an increasingly important role in biomedical research of preclinical area. Fluorescence molecular tomography (FMT) further upgrades the two-dimensional FMI optical information to three-dimensional fluorescent source distribution, which can greatly facilitate applications in related studies. However, FMT presents a challenging inverse problem which is quite ill-posed and ill-conditioned. Continuous efforts to develop more practical and efficient methods for FMT reconstruction are still needed. In this paper, a method based on spectral projected gradient pursuit (SPGP) has been proposed for FMT reconstruction. The proposed method was based on the directional pursuit framework. A mathematical strategy named the nonmonotone line search was associated with the SPGP method, which guaranteed the global convergence. In addition, the Barzilai-Borwein step length was utilized to build the new step length of the SPGP method, which was able to speed up the convergence of this gradient method. To evaluate the performance of the proposed method, several heterogeneous simulation experiments including multisource cases as well as comparative analyses have been conducted. The results demonstrated that, the proposed method was able to achieve satisfactory source localizations with a bias less than 1 mm; the computational efficiency of the method was one order of magnitude faster than the contrast method; and the fluorescence reconstructed by the proposed method had a higher contrast to the background than the contrast method. All the results demonstrated the potential for practical FMT applications with the proposed method.

  11. A Comparative Animal Study of Tendon Grafts Healing After Remnant-Preserving Versus Conventional Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Zhang, Lei; Jiang, Kan; Chai, Hao; Zhou, Mei; Bai, Jingping

    2016-01-01

    Background The aim of this study was to determine if anterior cruciate ligament (ACL) reconstruction by remnant preservation promotes cell proliferation, vascularization, proprioception recovery, and improved biomechanical properties of the tendon grafts. Material/Methods 75 New Zealand rabbits were randomly assigned into the control group (group A), conventional ACL reconstruction group (group B), ACL reconstruction using remnant preservation and graft through remnant sleeve technique group (group C), and ACL reconstruction using remnant preservation and remnant tensioning technique group (group D). The remnant and healing of tendon grafts in groups C and D were observed at 3, 6, and 12 weeks after surgery, and the mRNA expression levels of VEGF, NT-3 and GAP-43 in ACL (group A) or tendon graft samples (groups B, C, and D) were determined by real-time PCR. Tendon graft cell count, microvessel density (MVD), and proprioceptors were determined by H&E staining, CD34, and S-100 immunohistochemical staining. The biomechanical properties of the tendon graft at week 12 in groups B, C, and D were examined by using a tensile strength test. Results Remnant and tendon grafts were not healed at 3, 6, and 12 weeks after the operation in groups C and D. VEGF, NT-3, and GAP-43 mRNA expressions in groups B, C, and D were higher than those in group A (P<0.05), but no significant difference was observed between groups B, C, and D (P>0.05). Furthermore, tendon graft cell count, MVD, proprioception, and biomechanical properties showed no significant differences (P>0.05) among groups B, C, and D at various time points. Conclusions There was no significant difference in cell proliferation, vascularization, proprioception recovery, or biomechanical properties of the tendon grafts between remnant-preserving and conventional ACL reconstruction methods. PMID:27669454

  12. Bubble reconstruction method for wire-mesh sensors measurements

    NASA Astrophysics Data System (ADS)

    Mukin, Roman V.

    2016-08-01

    A new algorithm is presented for post-processing of void fraction measurements with wire-mesh sensors, particularly for identifying and reconstructing bubble surfaces in a two-phase flow. This method is a combination of the bubble recognition algorithm presented in Prasser (Nuclear Eng Des 237(15):1608, 2007) and Poisson surface reconstruction algorithm developed in Kazhdan et al. (Poisson surface reconstruction. In: Proceedings of the fourth eurographics symposium on geometry processing 7, 2006). To verify the proposed technique, a comparison was done of the reconstructed individual bubble shapes with those obtained numerically in Sato and Ničeno (Int J Numer Methods Fluids 70(4):441, 2012). Using the difference between reconstructed and referenced bubble shapes, the accuracy of the proposed algorithm was estimated. At the next step, the algorithm was applied to void fraction measurements performed in Ylönen (High-resolution flow structure measurements in a rod bundle (Diss., Eidgenössische Technische Hochschule ETH Zürich, Nr. 20961, 2013) by means of wire-mesh sensors in a rod bundle geometry. The reconstructed bubble shape yields bubble surface area and volume, hence its Sauter diameter d_{32} as well. Sauter diameter is proved to be more suitable for bubbles size characterization compared to volumetric diameter d_{30}, proved capable to capture the bi-disperse bubble size distribution in the flow. The effect of a spacer grid was studied as well: For the given spacer grid and considered flow rates, bubble size frequency distribution is obtained almost at the same position for all cases, approximately at d_{32} = 3.5 mm. This finding can be related to the specific geometry of the spacer grid or the air injection device applied in the experiments, or even to more fundamental properties of the bubble breakup and coagulation processes. In addition, an application of the new algorithm for reconstruction of a large air-water interface in a tube bundle is

  13. Limited Angle Reconstruction Method for Reconstructing Terrestrial Plasmaspheric Densities from EUV Images

    NASA Technical Reports Server (NTRS)

    Newman, Timothy; Santhanam, Naveen; Zhang, Huijuan; Gallagher, Dennis

    2003-01-01

    A new method for reconstructing the global 3D distribution of plasma densities in the plasmasphere from a limited number of 2D views is presented. The method is aimed at using data from the Extreme Ultra Violet (EUV) sensor on NASA s Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite. Physical properties of the plasmasphere are exploited by the method to reduce the level of inaccuracy imposed by the limited number of views. The utility of the method is demonstrated on synthetic data.

  14. Robust Methods for Sensing and Reconstructing Sparse Signals

    ERIC Educational Resources Information Center

    Carrillo, Rafael E.

    2012-01-01

    Compressed sensing (CS) is an emerging signal acquisition framework that goes against the traditional Nyquist sampling paradigm. CS demonstrates that a sparse, or compressible, signal can be acquired using a low rate acquisition process. Since noise is always present in practical data acquisition systems, sensing and reconstruction methods are…

  15. An improved reconstruction method for cosmological density fields

    NASA Technical Reports Server (NTRS)

    Gramann, Mirt

    1993-01-01

    This paper proposes some improvements to existing reconstruction methods for recovering the initial linear density and velocity fields of the universe from the present large-scale density distribution. We derive the Eulerian continuity equation in the Zel'dovich approximation and show that, by applying this equation, we can trace the evolution of the gravitational potential of the universe more exactly than is possible with previous approaches based on the Zel'dovich-Bernoulli equation. The improved reconstruction method is tested using N-body simulations. When the Zel'dovich-Bernoulli equation describes the formation of filaments, then the Zel'dovich continuity equation also follows the clustering of clumps inside the filaments. Our reconstruction method recovers the true initial gravitational potential with an rms error about 3 times smaller than previous methods. We examine the recovery of the initial distribution of Fourier components and find the scale at which the recovered phases are scrambled with respect their true initial values. Integrating the Zel'dovich continuity equation back in time, we can improve the spatial resolution of the reconstruction by a factor of about 2.

  16. 50 CFR 648.290 - Tilefish Annual Catch Limit (ACL).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... detailed review of fishery performance relative to the sector ACLs at least every 5 years. (1) If the ACL... recommendations to the MAFMC for changes in measures intended to ensure ACLs are not as frequently exceeded. (2...) Performance reviews shall not substitute for annual reviews that occur to ascertain if prior year ACLs...

  17. 50 CFR 648.290 - Tilefish Annual Catch Limit (ACL).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... detailed review of fishery performance relative to the sector ACLs at least every 5 years. (1) If the ACL... recommendations to the MAFMC for changes in measures intended to ensure ACLs are not as frequently exceeded. (2...) Performance reviews shall not substitute for annual reviews that occur to ascertain if prior year ACLs...

  18. 50 CFR 648.290 - Tilefish Annual Catch Limit (ACL).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... detailed review of fishery performance relative to the sector ACLs at least every 5 years. (1) If the ACL... recommendations to the MAFMC for changes in measures intended to ensure ACLs are not as frequently exceeded. (2...) Performance reviews shall not substitute for annual reviews that occur to ascertain if prior year ACLs...

  19. Method for image reconstruction of moving radionuclide source distribution

    DOEpatents

    Stolin, Alexander V.; McKisson, John E.; Lee, Seung Joon; Smith, Mark Frederick

    2012-12-18

    A method for image reconstruction of moving radionuclide distributions. Its particular embodiment is for single photon emission computed tomography (SPECT) imaging of awake animals, though its techniques are general enough to be applied to other moving radionuclide distributions as well. The invention eliminates motion and blurring artifacts for image reconstructions of moving source distributions. This opens new avenues in the area of small animal brain imaging with radiotracers, which can now be performed without the perturbing influences of anesthesia or physical restraint on the biological system.

  20. Endoscopic Skull Base Reconstruction: An Evolution of Materials and Methods.

    PubMed

    Sigler, Aaron C; D'Anza, Brian; Lobo, Brian C; Woodard, Troy; Recinos, Pablo F; Sindwani, Raj

    2017-03-31

    Endoscopic skull base surgery has developed rapidly over the last decade, in large part because of the expanding armamentarium of endoscopic repair techniques. This article reviews the available technologies and techniques, including vascularized and nonvascularized flaps, synthetic grafts, sealants and glues, and multilayer reconstruction. Understanding which of these repair methods is appropriate and under what circumstances is paramount to achieving success in this challenging but rewarding field. A graduated approach to skull base reconstruction is presented to provide a systematic framework to guide selection of repair technique to ensure a successful outcome while minimizing morbidity for the patient.

  1. Testing the global flow reconstruction method on coupled chaotic oscillators

    NASA Astrophysics Data System (ADS)

    Plachy, Emese; Kolláth, Zoltán

    2010-03-01

    Irregular behaviour of pulsating variable stars may occur due to low dimensional chaos. To determine the quantitative properties of the dynamics in such systems, we apply a suitable time series analysis, the global flow reconstruction method. The robustness of the reconstruction can be tested through the resultant quantities, like Lyapunov dimension and Fourier frequencies. The latter is specially important as it is directly derivable from the observed light curves. We have performed tests using coupled Rossler oscillators to investigate the possible connection between those quantities. In this paper we present our test results.

  2. 3D reconstruction methods of coronal structures by radio observations

    NASA Technical Reports Server (NTRS)

    Aschwanden, Markus J.; Bastian, T. S.; White, Stephen M.

    1992-01-01

    The ability to carry out the three dimensional (3D) reconstruction of structures in the solar corona would represent a major advance in the study of the physical properties in active regions and in flares. Methods which allow a geometric reconstruction of quasistationary coronal structures (for example active region loops) or dynamic structures (for example flaring loops) are described: stereoscopy of multi-day imaging observations by the VLA (Very Large Array); tomography of optically thin emission (in radio or soft x-rays); multifrequency band imaging by the VLA; and tracing of magnetic field lines by propagating electron beams.

  3. Functional Outcome of Transphyseal Reconstruction of the Anterior Cruciate Ligament in Skeletally Immature Patients

    PubMed Central

    Kim, Sung-Jae; Shim, Dong-Woo

    2012-01-01

    Purpose In anterior cruciate ligament (ACL) injury, conventional adult reconstruction techniques have to face the potential risk of growth disturbance or angular deformities in skeletally immature patients. The aim of this study was to evaluate the clinical outcomes of ACL reconstruction by conventional transphyseal tunnel technique. Materials and Methods On a retrospective basis, we reviewed 25 skeletally immature patients; all the patients showed skeletal maturity at last follow-up, and the mean age was 16.4 years. The average injury to surgery interval was 12.6 months. Clinical outcomes were assessed at a mean of 74.4 months postoperatively using the Lysholm Knee Scoring Scale, the Tegner activity level, the International Knee Documentation Committee (IKDC), and plain radiographs. Results All the patients had undergone transphyseal reconstruction of ACL. The mean Lysholm score was 48.36 points preoperatively and 93.32 points postoperatively; the mean Tegner activity level was changed from 3.0 points to 5.6 points. The mean IKDC level was categorized as C preoperatively and changed to A postoperatively. Conclusions Our midterm outcome at an average 6 years after surgery was satisfactory without significant leg length discrepancies or abnormal alignment of the knee joint. Transphyseal reconstruction of ACL is a good treatment modality in the skeletally immature patient. PMID:22977795

  4. Parallel MR image reconstruction using augmented Lagrangian methods.

    PubMed

    Ramani, Sathish; Fessler, Jeffrey A

    2011-03-01

    Magnetic resonance image (MRI) reconstruction using SENSitivity Encoding (SENSE) requires regularization to suppress noise and aliasing effects. Edge-preserving and sparsity-based regularization criteria can improve image quality, but they demand computation-intensive nonlinear optimization. In this paper, we present novel methods for regularized MRI reconstruction from undersampled sensitivity encoded data--SENSE-reconstruction--using the augmented Lagrangian (AL) framework for solving large-scale constrained optimization problems. We first formulate regularized SENSE-reconstruction as an unconstrained optimization task and then convert it to a set of (equivalent) constrained problems using variable splitting. We then attack these constrained versions in an AL framework using an alternating minimization method, leading to algorithms that can be implemented easily. The proposed methods are applicable to a general class of regularizers that includes popular edge-preserving (e.g., total-variation) and sparsity-promoting (e.g., l(1)-norm of wavelet coefficients) criteria and combinations thereof. Numerical experiments with synthetic and in vivo human data illustrate that the proposed AL algorithms converge faster than both general-purpose optimization algorithms such as nonlinear conjugate gradient (NCG) and state-of-the-art MFISTA.

  5. A new method of morphological comparison for bony reconstructive surgery: maxillary reconstruction using scapular tip bone

    NASA Astrophysics Data System (ADS)

    Chan, Harley; Gilbert, Ralph W.; Pagedar, Nitin A.; Daly, Michael J.; Irish, Jonathan C.; Siewerdsen, Jeffrey H.

    2010-02-01

    esthetic appearance is one of the most important factors for reconstructive surgery. The current practice of maxillary reconstruction chooses radial forearm, fibula or iliac rest osteocutaneous to recreate three-dimensional complex structures of the palate and maxilla. However, these bone flaps lack shape similarity to the palate and result in a less satisfactory esthetic. Considering similarity factors and vasculature advantages, reconstructive surgeons recently explored the use of scapular tip myo-osseous free flaps to restore the excised site. We have developed a new method that quantitatively evaluates the morphological similarity of the scapula tip bone and palate based on a diagnostic volumetric computed tomography (CT) image. This quantitative result was further interpreted as a color map that rendered on the surface of a three-dimensional computer model. For surgical planning, this color interpretation could potentially assist the surgeon to maximize the orientation of the bone flaps for best fit of the reconstruction site. With approval from the Research Ethics Board (REB) of the University Health Network, we conducted a retrospective analysis with CT image obtained from 10 patients. Each patient had a CT scans including the maxilla and chest on the same day. Based on this image set, we simulated total, subtotal and hemi palate reconstruction. The procedure of simulation included volume segmentation, conversing the segmented volume to a stereo lithography (STL) model, manual registration, computation of minimum geometric distances and curvature between STL model. Across the 10 patients data, we found the overall root-mean-square (RMS) conformance was 3.71+/- 0.16 mm

  6. Preferential Loading of the ACL Compared With the MCL During Landing

    PubMed Central

    Quatman, Carmen E.; Kiapour, Ata M.; Demetropoulos, Constantine K.; Kiapour, Ali; Wordeman, Samuel C.; Levine, Jason W.; Goel, Vijay K.; Hewett, Timothy E.

    2014-01-01

    Background Strong biomechanical and epidemiological evidence associates knee valgus collapse with isolated, noncontact anterior cruciate ligament (ACL) injuries. However, a concomitant injury to the medial collateral ligament (MCL) would be expected under valgus collapse, based on the MCL’s anatomic orientation and biomechanical role in knee stability. Purpose/Hypothesis The purpose of this study was to investigate the relative ACL to MCL strain patterns during physiological simulations of a wide range of high-risk dynamic landing scenarios. We hypothesized that both knee abduction and internal tibial rotation moments would generate a disproportionate increase in the ACL strain relative to the MCL strain. However, the physiological range of knee abduction and internal tibial rotation moments that produce ACL injuries are not of sufficient magnitude to compromise the MCL’s integrity consistently. Study Design Controlled laboratory study. Methods A novel in sim approach was used to test our hypothesis. Seventeen cadaveric lower extremities (mean age, 45 ± 7 years; 9 female and 8 male) were tested to simulate a broad range of landings after a jump under anterior tibial shear force, knee abduction, and internal tibial rotation at 25° of knee flexion. The ACL and MCL strains were quantified using differential variable reluctance transducers. An extensively validated, detailed finite element model of the lower extremity was used to help better interpret experimental findings. Results Anterior cruciate ligament failure occurred in 15 of 17 specimens (88%). Increased anterior tibial shear force and knee abduction and internal tibial rotation moments resulted in significantly higher ACL:MCL strain ratios (P < .05). Under all modes of single-planar and multiplanar loading, the ACL:MCL strain ratio remained greater than 1.7, while the relative ACL strain was significantly higher than the relative MCL strain (P < .01). Relative change in the ACL strain was demonstrated

  7. Runx2-Modified Adipose-Derived Stem Cells Promote Tendon Graft Integration in Anterior Cruciate Ligament Reconstruction.

    PubMed

    Zhang, Xin; Ma, Yong; Fu, Xin; Liu, Qiang; Shao, Zhenxing; Dai, Linghui; Pi, Yanbin; Hu, Xiaoqing; Zhang, Jiying; Duan, Xiaoning; Chen, Wenqing; Chen, Ping; Zhou, Chunyan; Ao, Yingfang

    2016-01-08

    Runx2 is a powerful osteo-inductive factor and adipose-derived stem cells (ADSCs) are multipotent. However, it is unknown whether Runx2-overexpressing ADSCs (Runx2-ADSCs) could promote anterior cruciate ligament (ACL) reconstruction. We evaluated the effect of Runx2-ADSCs on ACL reconstruction in vitro and in vivo. mRNA expressions of osteocalcin (OCN), bone sialoprotein (BSP) and collagen I (COLI) increased over time in Runx2-ADSCs. Runx2 overexpression inhibited LPL and PPARγ mRNA expressions. Runx2 induced alkaline phosphatase activity markedly. In nude mice injected with Runx2-ADSCs, promoted bone formation was detected by X-rays 8 weeks after injection. The healing of tendon-to-bone in a rabbit model of ACL reconstruction treated with Runx2-ADSCs, fibrin glue only and an RNAi targeting Runx2, was evaluated with CT 3D reconstruction, histological analysis and biomechanical methods. CT showed a greater degree of new bone formation around the bone tunnel in the group treated with Runx2-ADSCs compared with the fibrin glue group and RNAi Runx2 group. Histology showed that treatment with Runx2-ADSCs led to a rapid and significant increase at the tendon-to-bone compared with the control groups. Biomechanical tests demonstrated higher tendon pullout strength in the Runx2-ADSCs group at early time points. The healing of the attachment in ACL reconstruction was enhanced by Runx2-ADSCs.

  8. A Robust Shape Reconstruction Method for Facial Feature Point Detection.

    PubMed

    Tan, Shuqiu; Chen, Dongyi; Guo, Chenggang; Huang, Zhiqi

    2017-01-01

    Facial feature point detection has been receiving great research advances in recent years. Numerous methods have been developed and applied in practical face analysis systems. However, it is still a quite challenging task because of the large variability in expression and gestures and the existence of occlusions in real-world photo shoot. In this paper, we present a robust sparse reconstruction method for the face alignment problems. Instead of a direct regression between the feature space and the shape space, the concept of shape increment reconstruction is introduced. Moreover, a set of coupled overcomplete dictionaries termed the shape increment dictionary and the local appearance dictionary are learned in a regressive manner to select robust features and fit shape increments. Additionally, to make the learned model more generalized, we select the best matched parameter set through extensive validation tests. Experimental results on three public datasets demonstrate that the proposed method achieves a better robustness over the state-of-the-art methods.

  9. An Athlete's Nightmare: Tearing the ACL

    MedlinePlus

    ... women's knees tends to bend inward when women land." Some researchers believe that this inward bend may ... any athlete suffers ACL damage is because they land in a flat-footed position, as opposed to ...

  10. Arthroscopic Control for Safe and Secure Seating of Suspensory Devices for Femoral Fixation in Anterior Cruciate Ligament Reconstruction Using Three Different Techniques

    PubMed Central

    Kang, Seo Goo; Lee, Yong Seuk

    2017-01-01

    Purpose The purpose of this study was to evaluate the efficacy of our technique that allows direct visualization of seating of suspensory devices in anterior cruciate ligament (ACL) reconstruction. Materials and Methods Three different suspensory devices (TightRope RT, RetroButton, and EndoButton) were used in ACL reconstruction using 3 different techniques (outside-in, anteromedial [AM] portal, and transtibial techniques). Positioning of a guiding material and seating pattern of the suspensory devices were evaluated according to the surgical technique and suspensory device used. Results On the transtibial technique, 21 of total 26 cases (81%) of single bundle reconstructions and 22 of total 22 cases (100%) of double bundle reconstructions required superolateral capsulotomy where buttons were found in 21 of total 21 cases (100%) and 17 of 22 cases (77%), respectively. On the AM portal technique, all patients required capsulotomy and the button was found in only 18 of total 32 cases (56%) even after capsulotomy. On the outside-in technique, all patients required capsulotomy and the button was found in 86 of total 86 cases (100%). Conclusions Our technique for direct visualization of seating of the suspensory devices was more effective in outside-in and single bundle transtibial ACL reconstruction. However, it was less effective in double bundle transtibial and AM portal ACL reconstructions. PMID:28231646

  11. Adaptive Kaczmarz Method for Image Reconstruction in Electrical Impedance Tomography

    PubMed Central

    Li, Taoran; Kao, Tzu-Jen; Isaacson, David; Newell, Jonathan C.; Saulnier, Gary J.

    2013-01-01

    We present an adaptive Kaczmarz method for solving the inverse problem in electrical impedance tomography and determining the conductivity distribution inside an object from electrical measurements made on the surface. To best characterize an unknown conductivity distribution and avoid inverting the Jacobian-related term JTJ which could be expensive in terms of computation cost and memory in large scale problems, we propose solving the inverse problem by applying the optimal current patterns for distinguishing the actual conductivity from the conductivity estimate between each iteration of the block Kaczmarz algorithm. With a novel subset scheme, the memory-efficient reconstruction algorithm which appropriately combines the optimal current pattern generation with the Kaczmarz method can produce more accurate and stable solutions adaptively as compared to traditional Kaczmarz and Gauss-Newton type methods. Choices of initial current pattern estimates are discussed in the paper. Several reconstruction image metrics are used to quantitatively evaluate the performance of the simulation results. PMID:23718952

  12. Posteromedial Corner Reconstruction

    PubMed Central

    Ferrer, Gonzalo; Leon, Agustín; Wirth, Hans; Mena, Adolfo; Tuca, María José; Espinoza, Gonzalo

    2017-01-01

    Objective: Report the experience, after 1-year follow-up, of 30 patients who underwent anatomical knee reconstruction of posteromedial corner (PMC) injuries, using La Prade´s Technique. Methods: Retrospective cohort study of 30 consecutive patients with PMC injuries operated between November 2010 and May 2014 by the same surgical team. Inclusion criteria: patients with clinical presentation and images (stress radiographs and MRI) compatible with PMC injury, who maintained a grade III chronic instability in spite of at least 3 months of orthopedic treatment, who were reconstructed using La Prade’s anatomical technique, and completed at least 12 months of follow-up. Exclusion criteria: discordance between clinical and image studies, grade I or II medial instability, and surgery performed through a different technique. Data was collected by reviewing the electronic files and images. Functional scores (IKDC and Lysholm) were applied and registered in the preoperative evaluation, and then 6 and 12 months after surgery. Results: Thirty patients (28 men and 2 women) met the inclusion criteria. Mean age was 43 years (24-69). The vast majority (28 patients) had a high-energy mechanism of injury. Twenty patients were diagnosed in the acute setting, while 10 had a delayed diagnosis after poor results of concomitant ligament reconstructions. With the exception of 2 patients, who presented with isolated PMC injury, the majority had associated injuries as detailed: 11 cases had PMC + anterior cruciate ligament (ACL) injury, 3 patients had PMC + posterior cruciate ligament (PCL) injury, 3 patients had PMC + meniscal tears, 9 patients had PMC + ACL + PCL injuries, and there were 2 cases of PMC + ACL + PCL + lateral collateral ligament injuries. Mean time for PMC reconstruction surgery was 5 months (range 2-32). Lysholm and IKDC scores were 18,2 (2-69) and 24,3 (9,2-52,9) respectively in the preoperative setting, improving to 76,7 (44-94) and 70,7 (36,8-95,4) after 1-year follow

  13. Efficient ghost cell reconstruction for embedded boundary methods

    NASA Astrophysics Data System (ADS)

    Rapaka, Narsimha; Al-Marouf, Mohamad; Samtaney, Ravi

    2016-11-01

    A non-iterative linear reconstruction procedure for Cartesian grid embedded boundary methods is introduced. The method exploits the inherent geometrical advantage of the Cartesian grid and employs batch sorting of the ghost cells to eliminate the need for an iterative solution procedure. This reduces the computational cost of the reconstruction procedure significantly, especially for large scale problems in a parallel environment that have significant communication overhead, e.g., patch based adaptive mesh refinement (AMR) methods. In this approach, prior computation and storage of the weightage coefficients for the neighbour cells is not required which is particularly attractive for moving boundary problems and memory intensive stationary boundary problems. The method utilizes a compact and unique interpolation stencil but also provides second order spatial accuracy. It provides a single step/direct reconstruction for the ghost cells that enforces the boundary conditions on the embedded boundary. The method is extendable to higher order interpolations as well. Examples that demonstrate the advantages of the present approach are presented. Supported by the KAUST Office of Competitive Research Funds under Award No. URF/1/1394-01.

  14. Iterative reconstruction methods in X-ray CT.

    PubMed

    Beister, Marcel; Kolditz, Daniel; Kalender, Willi A

    2012-04-01

    Iterative reconstruction (IR) methods have recently re-emerged in transmission x-ray computed tomography (CT). They were successfully used in the early years of CT, but given up when the amount of measured data increased because of the higher computational demands of IR compared to analytical methods. The availability of large computational capacities in normal workstations and the ongoing efforts towards lower doses in CT have changed the situation; IR has become a hot topic for all major vendors of clinical CT systems in the past 5 years. This review strives to provide information on IR methods and aims at interested physicists and physicians already active in the field of CT. We give an overview on the terminology used and an introduction to the most important algorithmic concepts including references for further reading. As a practical example, details on a model-based iterative reconstruction algorithm implemented on a modern graphics adapter (GPU) are presented, followed by application examples for several dedicated CT scanners in order to demonstrate the performance and potential of iterative reconstruction methods. Finally, some general thoughts regarding the advantages and disadvantages of IR methods as well as open points for research in this field are discussed.

  15. Patient Outcomes and Predictors of Success After Revision Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Johnson, William R.; Makani, Amun; Wall, Andrew J.; Hosseini, Ali; Hampilos, Perry; Li, Guoan; Gill, Thomas J.

    2015-01-01

    Background: Patient outcomes and predictors of success after revision anterior cruciate ligament (ACL) reconstruction are currently limited in the literature. Existing studies either have a small study size or are difficult to interpret because of the multiple surgeons involved in the care of the study sample. Purpose: To determine patient outcomes and predictors of success or failure after a single-stage revision ACL reconstruction by a single fellowship-trained senior surgeon at a single institution. Study Design: Case series; Level of evidence, 4. Methods: A total of 78 patients who underwent revision ACL reconstruction by a single surgeon from 2010 to 2014 were contacted and available for follow-up. The mean time from revision procedure to follow-up was 52 months. Those patients who were able to participate in the study sent in a completed Tegner activity level scale, International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, and IKDC Current Health Assessment Form. The patients’ medical records were also thoroughly reviewed. Results: Five patients had subsequent failure after revision surgery. The median Tegner score was 6 at follow-up, and the mean subjective IKDC score was 72.5. There was no statistically significant difference in outcome scores when comparing revision graft type, body mass index, sex, need for bone grafting, and time from failure to revision. Patients with failures after primary ACL reconstruction secondary to a traumatic event were found to have statistically significantly higher IKDC scores (mean, 76.6) after revision when compared with nontraumatic failures (mean, 67.1), even when controlling for confounders (P < .017). Conclusion: Revision ACL reconstruction is effective in improving patient activity levels and satisfaction. However, the subjective IKDC results are quite variable and likely based on multiple factors. Patients with traumatic injuries contributing to graft failure after primary ACL reconstruction

  16. Improving automated 3D reconstruction methods via vision metrology

    NASA Astrophysics Data System (ADS)

    Toschi, Isabella; Nocerino, Erica; Hess, Mona; Menna, Fabio; Sargeant, Ben; MacDonald, Lindsay; Remondino, Fabio; Robson, Stuart

    2015-05-01

    This paper aims to provide a procedure for improving automated 3D reconstruction methods via vision metrology. The 3D reconstruction problem is generally addressed using two different approaches. On the one hand, vision metrology (VM) systems try to accurately derive 3D coordinates of few sparse object points for industrial measurement and inspection applications; on the other, recent dense image matching (DIM) algorithms are designed to produce dense point clouds for surface representations and analyses. This paper strives to demonstrate a step towards narrowing the gap between traditional VM and DIM approaches. Efforts are therefore intended to (i) test the metric performance of the automated photogrammetric 3D reconstruction procedure, (ii) enhance the accuracy of the final results and (iii) obtain statistical indicators of the quality achieved in the orientation step. VM tools are exploited to integrate their main functionalities (centroid measurement, photogrammetric network adjustment, precision assessment, etc.) into the pipeline of 3D dense reconstruction. Finally, geometric analyses and accuracy evaluations are performed on the raw output of the matching (i.e. the point clouds) by adopting a metrological approach. The latter is based on the use of known geometric shapes and quality parameters derived from VDI/VDE guidelines. Tests are carried out by imaging the calibrated Portable Metric Test Object, designed and built at University College London (UCL), UK. It allows assessment of the performance of the image orientation and matching procedures within a typical industrial scenario, characterised by poor texture and known 3D/2D shapes.

  17. Image reconstruction methods for the PBX-M pinhole camera.

    PubMed

    Holland, A; Powell, E T; Fonck, R J

    1991-09-10

    We describe two methods that have been used to reconstruct the soft x-ray emission profile of the PBX-M tokamak from the projected images recorded by the PBX-M pinhole camera [Proc. Soc. Photo-Opt. Instrum. Eng. 691, 111 (1986)]. Both methods must accurately represent the shape of the reconstructed profile while also providing a degree of immunity to noise in the data. The first method is a simple least-squares fit to the data. This has the advantage of being fast and small and thus easily implemented on the PDP-11 computer used to control the video digitizer for the pinhole camera. The second method involves the application of a maximum entropy algorithm to an overdetermined system. This has the advantage of allowing the use of a default profile. This profile contains additional knowledge about the plasma shape that can be obtained from equilibrium fits to the external magnetic measurements. Additionally the reconstruction is guaranteed positive, and the fit to the data can be relaxed by specifying both the amount and distribution of noise in the image. The algorithm described has the advantage of being considerably faster for an overdetermined system than the usual Lagrange multiplier approach to finding the maximum entropy solution [J. Opt. Soc. Am. 62, 511 (1972); Rev. Sci. Instrum. 57, 1557 (1986)].

  18. Pain Assessment After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Okoroha, Kelechi R.; Keller, Robert A.; Jung, Edward K.; Khalil, Lafi; Marshall, Nathan; Kolowich, Patricia A.; Moutzouros, Vasilios

    2016-01-01

    Background: Anterior cruciate ligament (ACL) reconstruction is a common outpatient procedure that is accompanied by significant postoperative pain. Purpose: To determine differences in acute pain levels between patients undergoing ACL reconstruction with bone–patellar tendon–bone (BTB) versus hamstring tendon (HS) autograft. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 70 patients who underwent primary ACL reconstruction using either BTB or HS autografts consented to participate. The primary outcome of the study was postoperative pain levels (visual analog scale), which were collected immediately after surgery and for 3 days postoperatively. Secondary outcome measures included opioid consumption (intravenous morphine equivalents), hours slept, patient satisfaction, reported breakthrough pain, and calls to the physician. Results: Patients treated with BTB had increased pain when compared with those treated with HS in the acute postoperative period (mean ± SD: day 0, 6.0 ± 1.7 vs 5.2 ± 2.0 [P = .066]; day 1, 5.9 ± 1.7 vs 4.9 ±1.7 [P = .024]; day 2, 5.2 ± 1.9 vs 4.1 ± 2.0 [P = .032]; day 3, 4.8 ± 2.1 vs 3.9 ± 2.3 [P = .151]). There were also significant increases in reported breakthrough pain (day 0, 76% vs 43% [P = .009]; day 1, 64% vs 35% [P = .003]) and calls to the physician due to pain (day 1, 19% vs 0% [P = .041]) in the BTB group. There were no significant differences in narcotic requirements or sleep disturbances. Overall, the BTB group reported significantly less satisfaction with pain management on days 0 and 1 (P = .024 and .027, respectively). Conclusion: A significant increase in acute postoperative pain was found when performing ACL reconstruction with BTB compared with HS. Patients treated with BTB were more likely to have breakthrough pain, decreased satisfaction with their pain management, and to contact their physician due to pain. These findings suggest a difference in early postoperative pain between the 2 most

  19. Optical Sensors and Methods for Underwater 3D Reconstruction

    PubMed Central

    Massot-Campos, Miquel; Oliver-Codina, Gabriel

    2015-01-01

    This paper presents a survey on optical sensors and methods for 3D reconstruction in underwater environments. The techniques to obtain range data have been listed and explained, together with the different sensor hardware that makes them possible. The literature has been reviewed, and a classification has been proposed for the existing solutions. New developments, commercial solutions and previous reviews in this topic have also been gathered and considered. PMID:26694389

  20. TRITON-X is most effective among three decellularization agents for ACL tissue engineering.

    PubMed

    Vavken, Patrick; Joshi, Shilpa; Murray, Martha M

    2009-12-01

    Ruptures of the anterior cruciate ligament (ACL) are still associated with high rates of long-term complications, even in patients undergoing modern, state-of-the-art replacement. Tissue-engineering approaches have been shown to be of value in improving treatment of ACL ruptures. However, the success of tissue-engineering procedures depends on the choice of an appropriate biomaterial. Decellularized ACL tissue potentially combines the structural composition of the targeted tissue with a reduced risk of graft rejection or disease transmission. In this study, we tested the effectiveness of currently available decellularization methods based on TRITON-X, sodium dodecyl sulfate (SDS), and trypsin. After identifying the most effective decellularization method, the capacity for reseeding with ACL fibroblasts was studied. All decellularization protocols reduced DNA content, with TRITON-X treatment having the greatest effect. Concurrently, decellularization did not affect tissue collagen or total protein content, but did decrease glycosaminoglycan content. TRITON-X also resulted the least glycosaminoglycan depletion. Porcine ACL tissue after decellularization with TRITON-X could be successfully reseeded with human ACL fibroblasts as demonstrated by steady DNA content and increasing pro-collagen expression.

  1. Efficient finite element method for grating profile reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, Ruming; Sun, Jiguang

    2015-12-01

    This paper concerns the reconstruction of grating profiles from scattering data. The inverse problem is formulated as an optimization problem with a regularization term. We devise an efficient finite element method (FEM) and employ a quasi-Newton method to solve it. For the direct problems, the FEM stiff and mass matrices are assembled once at the beginning of the numerical procedure. Then only minor changes are made to the mass matrix at each iteration, which significantly saves the computation cost. Numerical examples show that the method is effective and robust.

  2. Computational methods estimating uncertainties for profile reconstruction in scatterometry

    NASA Astrophysics Data System (ADS)

    Gross, H.; Rathsfeld, A.; Scholze, F.; Model, R.; Bär, M.

    2008-04-01

    The solution of the inverse problem in scatterometry, i.e. the determination of periodic surface structures from light diffraction patterns, is incomplete without knowledge of the uncertainties associated with the reconstructed surface parameters. With decreasing feature sizes of lithography masks, increasing demands on metrology techniques arise. Scatterometry as a non-imaging indirect optical method is applied to periodic line-space structures in order to determine geometric parameters like side-wall angles, heights, top and bottom widths and to evaluate the quality of the manufacturing process. The numerical simulation of the diffraction process is based on the finite element solution of the Helmholtz equation. The inverse problem seeks to reconstruct the grating geometry from measured diffraction patterns. Restricting the class of gratings and the set of measurements, this inverse problem can be reformulated as a non-linear operator equation in Euclidean spaces. The operator maps the grating parameters to the efficiencies of diffracted plane wave modes. We employ a Gauss-Newton type iterative method to solve this operator equation and end up minimizing the deviation of the measured efficiency or phase shift values from the simulated ones. The reconstruction properties and the convergence of the algorithm, however, is controlled by the local conditioning of the non-linear mapping and the uncertainties of the measured efficiencies or phase shifts. In particular, the uncertainties of the reconstructed geometric parameters essentially depend on the uncertainties of the input data and can be estimated by various methods. We compare the results obtained from a Monte Carlo procedure to the estimations gained from the approximative covariance matrix of the profile parameters close to the optimal solution and apply them to EUV masks illuminated by plane waves with wavelengths in the range of 13 nm.

  3. Reconstruction of the Sunspot Group Number: The Backbone Method

    NASA Astrophysics Data System (ADS)

    Svalgaard, Leif; Schatten, Kenneth H.

    2016-11-01

    We have reconstructed the sunspot-group count, not by comparisons with other reconstructions and correcting those where they were deemed to be deficient, but by a re-assessment of original sources. The resulting series is a pure solar index and does not rely on input from other proxies, e.g. radionuclides, auroral sightings, or geomagnetic records. "Backboning" the data sets, our chosen method, provides substance and rigidity by using long-time observers as a stiffness character. Solar activity, as defined by the Group Number, appears to reach and sustain for extended intervals of time the same level in each of the last three centuries since 1700 and the past several decades do not seem to have been exceptionally active, contrary to what is often claimed.

  4. Harmonizing multiple methods for reconstructing historical potential and reference evapotranspiration

    USGS Publications Warehouse

    Belaineh, Getachew; Sumner, David; Carter, Edward; Clapp, David

    2013-01-01

    Potential evapotranspiration (PET) and reference evapotranspiration (RET) data are usually critical components of hydrologic analysis. Many different equations are available to estimate PET and RET. Most of these equations, such as the Priestley-Taylor and Penman- Monteith methods, rely on detailed meteorological data collected at ground-based weather stations. Few weather stations collect enough data to estimate PET or RET using one of the more complex evapotranspiration equations. Currently, satellite data integrated with ground meteorological data are used with one of these evapotranspiration equations to accurately estimate PET and RET. However, earlier than the last few decades, historical reconstructions of PET and RET needed for many hydrologic analyses are limited by the paucity of satellite data and of some types of ground data. Air temperature stands out as the most generally available meteorological ground data type over the last century. Temperature-based approaches used with readily available historical temperature data offer the potential for long period-of-record PET and RET historical reconstructions. A challenge is the inconsistency between the more accurate, but more data intensive, methods appropriate for more recent periods and the less accurate, but less data intensive, methods appropriate to the more distant past. In this study, multiple methods are harmonized in a seamless reconstruction of historical PET and RET by quantifying and eliminating the biases of the simple Hargreaves-Samani method relative to the more complex and accurate Priestley-Taylor and Penman-Monteith methods. This harmonization process is used to generate long-term, internally consistent, spatiotemporal databases of PET and RET.

  5. Finite element study on the anatomic transtibial technique for single-bundle anterior cruciate ligament reconstruction.

    PubMed

    Bae, Ji Yong; Kim, Geon-Hee; Seon, Jong Keun; Jeon, Insu

    2016-05-01

    The anatomic transtibial (TT) technique is proposed as a new approach for single-bundle anterior cruciate ligament (ACL) reconstruction. Geometric models of the anatomic TT and anteromedial (AM) portal techniques were fabricated with a reconstructed knee joint model and virtual surgical operations. Grafts of 7 mm diameter were modeled and inserted into tunnels drilled in each model. In the models, the shape of the graft between the femur and the tibia, the lengths of the bone tunnels, and the femoral graft bending angles were evaluated. To evaluate the biomechanical effects of both techniques on the grafts, the contact pressures and maximum principal stresses in the grafts were calculated using the finite element method. The anatomic TT technique placed the femoral tunnel to the anatomic position of the native ACL femoral attachment site. In addition, it decreased the peak contact pressure and the maximum principal stress at the full extension position of the graft compared with the AM portal technique. The anatomic TT technique may be regarded as a superior surgical technique compared with the conventional TT and AM portal techniques. Because of the easy surgical operation involved, the technique decreases the operation time for ACL reconstruction and it provides a deformation behavior of grafts similar to that in the native ACL in a knee joint. With its few side effects, the anatomic TT technique may considerably help patients.

  6. Two-dimensional signal reconstruction: The correlation sampling method

    SciTech Connect

    Roman, H. E.

    2007-12-15

    An accurate approach for reconstructing a time-dependent two-dimensional signal from non-synchronized time series recorded at points located on a grid is discussed. The method, denoted as correlation sampling, improves the standard conditional sampling approach commonly employed in the study of turbulence in magnetoplasma devices. Its implementation is illustrated in the case of an artificial time-dependent signal constructed using a fractal algorithm that simulates a fluctuating surface. A statistical method is also discussed for distinguishing coherent (i.e., collective) from purely random (noisy) behavior for such two-dimensional fluctuating phenomena.

  7. Comparing 3D virtual methods for hemimandibular body reconstruction.

    PubMed

    Benazzi, Stefano; Fiorenza, Luca; Kozakowski, Stephanie; Kullmer, Ottmar

    2011-07-01

    Reconstruction of fractured, distorted, or missing parts in human skeleton presents an equal challenge in the fields of paleoanthropology, bioarcheology, forensics, and medicine. This is particularly important within the disciplines such as orthodontics and surgery, when dealing with mandibular defects due to tumors, developmental abnormalities, or trauma. In such cases, proper restorations of both form (for esthetic purposes) and function (restoration of articulation, occlusion, and mastication) are required. Several digital approaches based on three-dimensional (3D) digital modeling, computer-aided design (CAD)/computer-aided manufacturing techniques, and more recently geometric morphometric methods have been used to solve this problem. Nevertheless, comparisons among their outcomes are rarely provided. In this contribution, three methods for hemimandibular body reconstruction have been tested. Two bone defects were virtually simulated in a 3D digital model of a human hemimandible. Accordingly, 3D digital scaffolds were obtained using the mirror copy of the unaffected hemimandible (Method 1), the thin plate spline (TPS) interpolation (Method 2), and the combination between TPS and CAD techniques (Method 3). The mirror copy of the unaffected hemimandible does not provide a suitable solution for bone restoration. The combination between TPS interpolation and CAD techniques (Method 3) produces an almost perfect-fitting 3D digital model that can be used for biocompatible custom-made scaffolds generated by rapid prototyping technologies.

  8. Acellular Dermal Matrix as a Core Strut for Projection in Nipple Reconstruction: Approaches for Three Different Methods of Breast Reconstruction

    PubMed Central

    Park, Gui-Yong; Cho, Hee-Eun; Lee, Byung-Il; Park, Seung-Ha

    2016-01-01

    Background The objective of this paper was to describe a novel technique for improving the maintenance of nipple projection in primary nipple reconstruction by using acellular dermal matrix as a strut in one of three different configurations, according to the method of prior breast reconstruction. The struts were designed to best fill the different types of dead spaces in nipple reconstruction depending on the breast reconstruction method. Methods A total of 50 primary nipple reconstructions were performed between May 2012 and May 2015. The prior breast reconstruction methods were latissimus dorsi (LD) flap (28 cases), transverse rectus abdominis myocutaneous (TRAM) flap (10 cases), or tissue expander/implant (12 cases). The nipple reconstruction technique involved the use of local flaps, including the C-V flap or star flap. A 1×2-cm acellular dermal matrix was placed into the core with O-, I-, and L-shaped struts for prior LD, TRAM, and expander/implant methods, respectively. The projection of the reconstructed nipple was measured at the time of surgery and at 3, 6, and 9 months postoperatively. Results The nine-month average maintenance of nipple projection was 73.0%±9.67% for the LD flap group using an O-strut, 72.0%±11.53% for the TRAM flap group using an I-strut, and 69.0%±10.82% for the tissue expander/implant group using an L-strut. There were no cases of infection, wound dehiscence, or flap necrosis. Conclusions The application of an acellular dermal matrix with a different kind of strut for each of 3 breast reconstruction methods is an effective addition to current techniques for improving the maintenance of long-term projection in primary nipple reconstruction. PMID:27689049

  9. An Assessment of Iterative Reconstruction Methods for Sparse Ultrasound Imaging

    PubMed Central

    Valente, Solivan A.; Zibetti, Marcelo V. W.; Pipa, Daniel R.; Maia, Joaquim M.; Schneider, Fabio K.

    2017-01-01

    Ultrasonic image reconstruction using inverse problems has recently appeared as an alternative to enhance ultrasound imaging over beamforming methods. This approach depends on the accuracy of the acquisition model used to represent transducers, reflectivity, and medium physics. Iterative methods, well known in general sparse signal reconstruction, are also suited for imaging. In this paper, a discrete acquisition model is assessed by solving a linear system of equations by an ℓ1-regularized least-squares minimization, where the solution sparsity may be adjusted as desired. The paper surveys 11 variants of four well-known algorithms for sparse reconstruction, and assesses their optimization parameters with the goal of finding the best approach for iterative ultrasound imaging. The strategy for the model evaluation consists of using two distinct datasets. We first generate data from a synthetic phantom that mimics real targets inside a professional ultrasound phantom device. This dataset is contaminated with Gaussian noise with an estimated SNR, and all methods are assessed by their resulting images and performances. The model and methods are then assessed with real data collected by a research ultrasound platform when scanning the same phantom device, and results are compared with beamforming. A distinct real dataset is finally used to further validate the proposed modeling. Although high computational effort is required by iterative methods, results show that the discrete model may lead to images closer to ground-truth than traditional beamforming. However, computing capabilities of current platforms need to evolve before frame rates currently delivered by ultrasound equipments are achievable. PMID:28282862

  10. Tensor-based dynamic reconstruction method for electrical capacitance tomography

    NASA Astrophysics Data System (ADS)

    Lei, J.; Mu, H. P.; Liu, Q. B.; Li, Z. H.; Liu, S.; Wang, X. Y.

    2017-03-01

    Electrical capacitance tomography (ECT) is an attractive visualization measurement method, in which the acquisition of high-quality images is beneficial for the understanding of the underlying physical or chemical mechanisms of the dynamic behaviors of the measurement objects. In real-world measurement environments, imaging objects are often in a dynamic process, and the exploitation of the spatial-temporal correlations related to the dynamic nature will contribute to improving the imaging quality. Different from existing imaging methods that are often used in ECT measurements, in this paper a dynamic image sequence is stacked into a third-order tensor that consists of a low rank tensor and a sparse tensor within the framework of the multiple measurement vectors model and the multi-way data analysis method. The low rank tensor models the similar spatial distribution information among frames, which is slowly changing over time, and the sparse tensor captures the perturbations or differences introduced in each frame, which is rapidly changing over time. With the assistance of the Tikhonov regularization theory and the tensor-based multi-way data analysis method, a new cost function, with the considerations of the multi-frames measurement data, the dynamic evolution information of a time-varying imaging object and the characteristics of the low rank tensor and the sparse tensor, is proposed to convert the imaging task in the ECT measurement into a reconstruction problem of a third-order image tensor. An effective algorithm is developed to search for the optimal solution of the proposed cost function, and the images are reconstructed via a batching pattern. The feasibility and effectiveness of the developed reconstruction method are numerically validated.

  11. Reconstruction and analysis of hybrid composite shells using meshless methods

    NASA Astrophysics Data System (ADS)

    Bernardo, G. M. S.; Loja, M. A. R.

    2017-02-01

    The importance of focusing on the research of viable models to predict the behaviour of structures which may possess in some cases complex geometries is an issue that is growing in different scientific areas, ranging from the civil and mechanical engineering to the architecture or biomedical devices fields. In these cases, the research effort to find an efficient approach to fit laser scanning point clouds, to the desired surface, has been increasing, leading to the possibility of modelling as-built/as-is structures and components' features. However, combining the task of surface reconstruction and the implementation of a structural analysis model is not a trivial task. Although there are works focusing those different phases in separate, there is still an effective need to find approaches able to interconnect them in an efficient way. Therefore, achieving a representative geometric model able to be subsequently submitted to a structural analysis in a similar based platform is a fundamental step to establish an effective expeditious processing workflow. With the present work, one presents an integrated methodology based on the use of meshless approaches, to reconstruct shells described by points' clouds, and to subsequently predict their static behaviour. These methods are highly appropriate on dealing with unstructured points clouds, as they do not need to have any specific spatial or geometric requirement when implemented, depending only on the distance between the points. Details on the formulation, and a set of illustrative examples focusing the reconstruction of cylindrical and double-curvature shells, and its further analysis, are presented.

  12. An improved image reconstruction method for optical intensity correlation Imaging

    NASA Astrophysics Data System (ADS)

    Gao, Xin; Feng, Lingjie; Li, Xiyu

    2016-12-01

    The intensity correlation imaging method is a novel kind of interference imaging and it has favorable prospects in deep space recognition. However, restricted by the low detecting signal-to-noise ratio (SNR), it's usually very difficult to obtain high-quality image of deep space object like high-Earth-orbit (HEO) satellite with existing phase retrieval methods. In this paper, based on the priori intensity statistical distribution model of the object and characteristics of measurement noise distribution, an improved method of Prior Information Optimization (PIO) is proposed to reduce the ambiguous images and accelerate the phase retrieval procedure thus realizing fine image reconstruction. As the simulations and experiments show, compared to previous methods, our method could acquire higher-resolution images with less error in low SNR condition.

  13. A Robust Shape Reconstruction Method for Facial Feature Point Detection

    PubMed Central

    Huang, Zhiqi

    2017-01-01

    Facial feature point detection has been receiving great research advances in recent years. Numerous methods have been developed and applied in practical face analysis systems. However, it is still a quite challenging task because of the large variability in expression and gestures and the existence of occlusions in real-world photo shoot. In this paper, we present a robust sparse reconstruction method for the face alignment problems. Instead of a direct regression between the feature space and the shape space, the concept of shape increment reconstruction is introduced. Moreover, a set of coupled overcomplete dictionaries termed the shape increment dictionary and the local appearance dictionary are learned in a regressive manner to select robust features and fit shape increments. Additionally, to make the learned model more generalized, we select the best matched parameter set through extensive validation tests. Experimental results on three public datasets demonstrate that the proposed method achieves a better robustness over the state-of-the-art methods. PMID:28316615

  14. The impact of HGT on phylogenomic reconstruction methods.

    PubMed

    Lapierre, Pascal; Lasek-Nesselquist, Erica; Gogarten, Johann Peter

    2014-01-01

    Supermatrix and supertree analyses are frequently used to more accurately recover vertical evolutionary history but debate still exists over which method provides greater reliability. Traditional methods that resolve relationships among organisms from single genes are often unreliable because of the frequent lack of strong phylogenetic signal and the presence of systematic artifacts. Methods developed to reconstruct organismal history from multiple genes can be divided into supermatrix and supertree approaches. A supermatrix analysis consists of the concatenation of multiple genes into a single, possibly partitioned alignment, from which phylogenies are reconstructed using a variety of approaches. Supertrees build consensus trees from the topological information contained within individual gene trees. Both methods are now widely used and have been demonstrated to solve previously ambiguous or unresolved phylogenies with high statistical support. However, the amount of misleading signal needed to induce erroneous phylogenies for both strategies is still unknown. Using genome simulations, we test the accuracy of supertree and supermatrix approaches in recovering the true organismal phylogeny under increased amounts of horizontally transferred genes and changes in substitution rates. Our results show that overall, supermatrix approaches are preferable when a low amount of gene transfer is suspected to be present in the dataset, while supertrees have greater reliability in the presence of a moderate amount of misleading gene transfers. In the face of very high or very low substitution rates without horizontal gene transfers, supermatrix approaches outperform supertrees as individual gene trees remain unresolved and additional sequences contribute to a congruent phylogenetic signal.

  15. ACL Tears on The Rise Among Kids, Especially Girls

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_163730.html ACL Tears on the Rise Among Kids, Especially Girls ... A common knee injury -- an anterior cruciate ligament (ACL) tear -- has steadily increased among 6- to 18- ...

  16. Image reconstruction by the speckle-masking method.

    PubMed

    Weigelt, G; Wirnitzer, B

    1983-07-01

    Speckle masking is a method for reconstructing high-resolution images of general astronomical objects from stellar speckle interferograms. In speckle masking no unresolvable star is required within the isoplanatic patch of the object. We present digital applications of speckle masking to close spectroscopic double stars. The speckle interferograms were recorded with the European Southern Observatory's 3.6-m telescope. Diffraction-limited resolution (0.03 arc see) was achieved, which is about 30 times higher than the resolution of conventional astrophotography.

  17. Accelerated signal encoding and reconstruction using pixon method

    DOEpatents

    Puetter, Richard; Yahil, Amos; Pina, Robert

    2005-05-17

    The method identifies a Pixon element, which is a fundamental and indivisible unit of information, and a Pixon basis, which is the set of possible functions from which the Pixon elements are selected. The actual Pixon elements selected from this basis during the reconstruction process represents the smallest number of such units required to fit the data and representing the minimum number of parameters necessary to specify the image. The Pixon kernels can have arbitrary properties (e.g., shape, size, and/or position) as needed to best fit the data.

  18. Accelerated signal encoding and reconstruction using pixon method

    DOEpatents

    Puetter, Richard; Yahil, Amos

    2002-01-01

    The method identifies a Pixon element, which is a fundamental and indivisible unit of information, and a Pixon basis, which is the set of possible functions from which the Pixon elements are selected. The actual Pixon elements selected from this basis during the reconstruction process represents the smallest number of such units required to fit the data and representing the minimum number of parameters necessary to specify the image. The Pixon kernels can have arbitrary properties (e.g., shape, size, and/or position) as needed to best fit the data.

  19. Accelerated signal encoding and reconstruction using pixon method

    DOEpatents

    Puetter, Richard; Yahil, Amos

    2002-01-01

    The method identifies a Pixon element, which is a fundamental and indivisible unit of information, and a Pixon basis, which is the set of possible functions from which the Pixon elements are selected. The actual Pixon elements selected from this basis during the reconstruction process represents the smallest number of such units required to fit the data and representing the minimum number of parameters necessary to specify the image. The Pixon kernels can have arbitrary properties (e.g., shape size, and/or position) as needed to best fit the data.

  20. Increased Compliance With Supervised Rehabilitation Improves Functional Outcome and Return to Sport After Anterior Cruciate Ligament Reconstruction in Recreational Athletes

    PubMed Central

    Han, Fucai; Banerjee, Anirban; Shen, Liang; Krishna, Lingaraj

    2015-01-01

    Background: Successful return to sport is an important outcome measure after anterior cruciate ligament (ACL) reconstruction and a reason for patients’ decisions to elect surgery. Rehabilitation programs supervised by physical therapists are routinely prescribed after ACL reconstruction surgery. However, the added advantage of supervised physical therapy after ACL reconstruction is still debatable. Hypothesis: Attending more supervised physical therapy sessions after arthroscopic ACL reconstruction in recreational athletes increases their chance of successful return to sport. Study Design: Cohort study; Level of evidence, 3. Methods: The authors analyzed 93 recreational athletes who underwent arthroscopic ACL reconstruction. After arthroscopic single-bundle ACL reconstruction, patients were advised to attend 20 supervised physical therapy sessions. Patients’ demographics, surgical details, and outcome measures (Knee injury and Osteoarthritis Outcome Score [KOOS], Lysholm scale, and Short Form–36 Health Survey [SF-36]) were recorded presurgery and at 1-year follow-up. Ability to return to sports was documented through patients’ self-report. The attendance at physical therapy by each patient was obtained by examining database records and assessed as fully compliant (>15 sessions), moderately compliant (6-15 sessions), or noncompliant (<6 sessions). Results: Patients in the fully compliant group had significantly greater odds (odds ratio [OR], 18.5; 95% CI, 1.9-184.5; P = .013) of a successful return to sport as compared with the noncompliant group. Patients in the moderately compliant group also had greater odds of returning to sport as compared with the noncompliant group (OR, 4.2; 95% CI, 1.0-16.6; P = .043). Patients in the fully compliant group had significantly greater scores on the Lysholm (P < .001), KOOS Sports and Recreation subscale (P = .021), KOOS Symptoms subscale (P = .040), and SF-36 physical component summary (PCS) (P = .012) as compared with

  1. Algebraic filter approach for fast approximation of nonlinear tomographic reconstruction methods

    NASA Astrophysics Data System (ADS)

    Plantagie, Linda; Batenburg, Kees Joost

    2015-01-01

    We present a computational approach for fast approximation of nonlinear tomographic reconstruction methods by filtered backprojection (FBP) methods. Algebraic reconstruction algorithms are the methods of choice in a wide range of tomographic applications, yet they require significant computation time, restricting their usefulness. We build upon recent work on the approximation of linear algebraic reconstruction methods and extend the approach to the approximation of nonlinear reconstruction methods which are common in practice. We demonstrate that if a blueprint image is available that is sufficiently similar to the scanned object, our approach can compute reconstructions that approximate iterative nonlinear methods, yet have the same speed as FBP.

  2. A New Method for Coronal Magnetic Field Reconstruction

    NASA Astrophysics Data System (ADS)

    Yi, Sibaek; Choe, Gwangson; Lim, Daye

    2015-08-01

    We present a new, simple, variational method for reconstruction of coronal force-free magnetic fields based on vector magnetogram data. Our method employs vector potentials for magnetic field description in order to ensure the divergence-free condition. As boundary conditions, it only requires the normal components of magnetic field and current density so that the boundary conditions are not over-specified as in many other methods. The boundary normal current distribution is initially fixed once and for all and does not need continual adjustment as in stress-and-relax type methods. We have tested the computational code based on our new method in problems with known solutions and those with actual photospheric data. When solutions are fully given at all boundaries, the accuracy of our method is almost comparable to best performing methods in the market. When magnetic field data are given only at the photospheric boundary, our method excels other methods in most “figures of merit” devised by Schrijver et al. (2006). Furthermore the residual force in the solution is at least an order of magnitude smaller than that of any other method. It can also accommodate the source-surface boundary condition at the top boundary. Our method is expected to contribute to the real time monitoring of the sun required for future space weather forecasts.

  3. Local motion-compensated method for high-quality 3D coronary artery reconstruction

    PubMed Central

    Liu, Bo; Bai, Xiangzhi; Zhou, Fugen

    2016-01-01

    The 3D reconstruction of coronary artery from X-ray angiograms rotationally acquired on C-arm has great clinical value. While cardiac-gated reconstruction has shown promising results, it suffers from the problem of residual motion. This work proposed a new local motion-compensated reconstruction method to handle this issue. An initial image was firstly reconstructed using a regularized iterative reconstruction method. Then a 3D/2D registration method was proposed to estimate the residual vessel motion. Finally, the residual motion was compensated in the final reconstruction using the extended iterative reconstruction method. Through quantitative evaluation, it was found that high-quality 3D reconstruction could be obtained and the result was comparable to state-of-the-art method. PMID:28018741

  4. Local motion-compensated method for high-quality 3D coronary artery reconstruction.

    PubMed

    Liu, Bo; Bai, Xiangzhi; Zhou, Fugen

    2016-12-01

    The 3D reconstruction of coronary artery from X-ray angiograms rotationally acquired on C-arm has great clinical value. While cardiac-gated reconstruction has shown promising results, it suffers from the problem of residual motion. This work proposed a new local motion-compensated reconstruction method to handle this issue. An initial image was firstly reconstructed using a regularized iterative reconstruction method. Then a 3D/2D registration method was proposed to estimate the residual vessel motion. Finally, the residual motion was compensated in the final reconstruction using the extended iterative reconstruction method. Through quantitative evaluation, it was found that high-quality 3D reconstruction could be obtained and the result was comparable to state-of-the-art method.

  5. RELIABILITY AND VALIDITY OF A MODIFIED ISOMETRIC DYNAMOMETER IN THE ASSESSMENT OF MUSCULAR PERFORMANCE IN INDIVIDUALS WITH ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

    PubMed Central

    de Vasconcelos, Rodrigo Antunes; Bevilaqua-Grossi, Débora; Shimano, Antonio Carlos; Paccola, Cleber Jansen; Salvini, Tânia Fátima; Prado, Christiane Lanatovits; Junior, Wilson A. Mello

    2015-01-01

    Objectives: The aim of this study was to evaluate the reliability and validity of a modified isometric dynamometer (MID) in performance deficits of the knee extensor and flexor muscles in normal individuals and in those with ACL reconstructions. Methods: Sixty male subjects were invited to participate of the study, being divided into three groups with 20 subjects each: control group (GC), group of individuals with ACL reconstruction with patellar tendon graft (GTP, and group of individuals with ACL reconstruction with hamstrings graft (GTF). All individuals performed isometric tests in the MID, muscular strength deficits collected were subsequently compared to the tests performed on the Biodex System 3 operating in the isometric and isokinetic mode at speeds of 60°/s and 180o/s. Intraclass ICC correlation calculations were done in order to assess MID reliability, specificity, sensitivity and Kappa's consistency coefficient calculations, respectively, for assessing the MID's validity in detecting muscular deficits and intra- and intergroup comparisons when performing the four strength tests using the ANOVA method. Results: The modified isometric dynamometer (MID) showed excellent reliability and good validity in the assessment of the performance of the knee extensor and flexor muscles groups. In the comparison between groups, the GTP showed significantly greater deficits as compared to the GTF and GC groups. Conclusion: Isometric dynamometers connected to mechanotherapy equipments could be an alternative option to collect data concerning performance deficits of the extensor and flexor muscles groups of the knee in subjects with ACL reconstruction. PMID:27004175

  6. Post-refinement multiscale method for pin power reconstruction

    SciTech Connect

    Collins, B.; Seker, V.; Downar, T.; Xu, Y.

    2012-07-01

    The ability to accurately predict local pin powers in nuclear reactors is necessary to understand the mechanisms that cause fuel pin failure during steady state and transient operation. In the research presented here, methods are developed to improve the local solution using high order methods with boundary conditions from a low order global solution. Several different core configurations were tested to determine the improvement in the local pin powers compared to the standard techniques based on diffusion theory and pin power reconstruction (PPR). The post-refinement multiscale methods use the global solution to determine boundary conditions for the local solution. The local solution is solved using either a fixed boundary source or an albedo boundary condition; this solution is 'post-refinement' and thus has no impact on the global solution. (authors)

  7. Elastography Method for Reconstruction of Nonlinear Breast Tissue Properties

    PubMed Central

    Wang, Z. G.; Liu, Y.; Wang, G.; Sun, L. Z.

    2009-01-01

    Elastography is developed as a quantitative approach to imaging linear elastic properties of tissues to detect suspicious tumors. In this paper a nonlinear elastography method is introduced for reconstruction of complex breast tissue properties. The elastic parameters are estimated by optimally minimizing the difference between the computed forces and experimental measures. A nonlinear adjoint method is derived to calculate the gradient of the objective function, which significantly enhances the numerical efficiency and stability. Simulations are conducted on a three-dimensional heterogeneous breast phantom extracting from real imaging including fatty tissue, glandular tissue, and tumors. An exponential-form of nonlinear material model is applied. The effect of noise is taken into account. Results demonstrate that the proposed nonlinear method opens the door toward nonlinear elastography and provides guidelines for future development and clinical application in breast cancer study. PMID:19636362

  8. Reducing the Risk of ACL Injury in Female Athletes

    ERIC Educational Resources Information Center

    McDaniel, Larry W.; Rasche, Adrienna; Gaudet, Laura; Jackson, Allen

    2010-01-01

    The Anterior Cruciate Ligament (ACL) is located behind the kneecap (patella) and connects the thigh bone (femur) to the shin bone (tibia). Stabilizing the knee joint is the primary responsibility of the ACL. Injuries that affect the ACL are three to five times more common in females than males. This is a result of anatomical, biomechanical,…

  9. 50 CFR 648.120 - Scup Annual Catch Limit (ACL).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... shall recommend to the MAFMC separate ACLs for the commercial and recreational scup fisheries, the sum... and recreational fishing sector ACLs will be established consistent with the allocation guidelines... recreational sector ACLs may be established on an annual basis for up to 3 years at a time, dependent...

  10. 50 CFR 648.120 - Scup Annual Catch Limit (ACL).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... shall recommend to the MAFMC separate ACLs for the commercial and recreational scup fisheries, the sum... and recreational fishing sector ACLs will be established consistent with the allocation guidelines... recreational sector ACLs may be established on an annual basis for up to 3 years at a time, dependent...

  11. 50 CFR 648.120 - Scup Annual Catch Limit (ACL).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... shall recommend to the MAFMC separate ACLs for the commercial and recreational scup fisheries, the sum... and recreational fishing sector ACLs will be established consistent with the allocation guidelines... recreational sector ACLs may be established on an annual basis for up to 3 years at a time, dependent...

  12. Multi-rater Agreement in the Assessment of Anterior Cruciate Ligament Reconstruction Failure. A Radiographic and Video Analysis of the MARS Cohort

    PubMed Central

    Matava, Matthew J.; Arciero, Robert A.; Baumgarten, Keith M.; Carey, James L.; DeBerardino, Thomas M.; Hame, Sharon L.; Hannafin, Jo A.; Miller, Bruce S.; Nissen, Carl W.; Taft, Timothy N.; Wolf, Brian R.; Wright, Rick W.

    2015-01-01

    Background ACL reconstruction failure occurs in up to 10% of cases. Technical errors are considered the most common cause of graft failure despite the absence of validated studies. There is limited data regarding the agreement among orthopedic surgeons in terms of the etiology of primary ACL reconstruction failure and accuracy of graft tunnel placement. Purpose The purpose of this study is to test the hypothesis that experienced knee surgeons have a high level of inter-observer reliability in the agreement of the etiology of the primary ACL reconstruction failure, anatomical graft characteristics, tunnel placement. Methods Twenty cases of revision ACL reconstruction were randomly selected from the MARS database. Each case included the patient's history, standardized radiographs, and a concise 30-second arthroscopic video taken at the time of revision demonstrating the graft remnant and location of the tunnel apertures. 10 MARS surgeons not involved with the primary surgery reviewed all 20 cases. Each surgeon completed a two-part questionnaire dealing with each surgeon's training and practice as well as the placement of the femoral and tibial tunnels, condition of the primary graft, and the surgeon's opinion as to the etiology of graft failure. Inter-rater agreement was determined for each question. Inter-rater agreement was determined for each question with the kappa coefficient and prevalence adjusted bias adjusted kappa (PABAK). Results The 10 reviewers were in practice an average of 14 years. All performed at least 25 ACL reconstructions per year and 9 were fellowship-trained in sports medicine. There was wide variability in agreement among knee experts as to the specific etiology of ACL graft failure. When specifically asked about technical error as the cause for failure, inter-observer agreement was only slight (prevalence adjusted bias adjusted kappa [PABAK]: 0.26). There was fair overall agreement on ideal femoral tunnel placement (PABAK: 0.55), but only

  13. Comparison of pulse phase and thermographic signal reconstruction processing methods

    NASA Astrophysics Data System (ADS)

    Oswald-Tranta, Beata; Shepard, Steven M.

    2013-05-01

    Active thermography data for nondestructive testing has traditionally been evaluated by either visual or numerical identification of anomalous surface temperature contrast in the IR image sequence obtained as the target sample cools in response to thermal stimulation. However, in recent years, it has been demonstrated that considerably more information about the subsurface condition of a sample can be obtained by evaluating the time history of each pixel independently. In this paper, we evaluate the capabilities of two such analysis techniques, Pulse Phase Thermography (PPT) and Thermographic Signal Reconstruction (TSR) using induction and optical flash excitation. Data sequences from optical pulse and scanned induction heating are analyzed with both methods. Results are evaluated in terms of signal-tobackground ratio for a given subsurface feature. In addition to the experimental data, we present finite element simulation models with varying flaw diameter and depth, and discuss size measurement accuracy and the effect of noise on detection limits and sensitivity for both methods.

  14. Effect of ski boot rear stiffness (SBRS) on maximal ACL force during injury prone landing movements in alpine ski racing: A study with a musculoskeletal simulation model.

    PubMed

    Eberle, Robert; Heinrich, Dieter; Kaps, Peter; Oberguggenberger, Michael; Nachbauer, Werner

    2017-06-01

    A common anterior cruciate ligament (ACL) injury situation in alpine ski racing is landing back-weighted after a jump. Simulated back-weighted landing situations showed higher ACL-injury risk for increasing ski boot rear stiffness (SBRS) without considering muscles. It is well known that muscle forces affect ACL tensile forces during landing. The purpose of this study is to investigate the effect of different SBRS on the maximal ACL tensile forces during injury prone landings considering muscle forces by a two-dimensional musculoskeletal simulation model. Injury prone situations for ACL-injuries were generated by the musculoskeletal simulation model using measured kinematics of a non-injury situation and the method of Monte Carlo simulation. Subsequently, the SBRS was varied for injury prone landings. The maximal ACL tensile forces and contributing factors to the ACL forces were compared for the different SBRS. In the injury prone landings the maximal ACL tensile forces increased with increasing SBRS. It was found that the higher maximal ACL force was caused by higher forces acting on the tibia by the boot and by higher quadriceps muscle forces both due to the higher SBRS. Practical experience suggested that the reduction of SBRS is not accepted by ski racers due to performance reasons. Thus, preventive measures may concentrate on the reduction of the quadriceps muscle force during impact.

  15. Comparison of image reconstruction methods for structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Lukeš, Tomas; Hagen, Guy M.; Křížek, Pavel; Švindrych, Zdeněk.; Fliegel, Karel; Klíma, Miloš

    2014-05-01

    Structured illumination microscopy (SIM) is a recent microscopy technique that enables one to go beyond the diffraction limit using patterned illumination. The high frequency information is encoded through aliasing into the observed image. By acquiring multiple images with different illumination patterns aliased components can be separated and a highresolution image reconstructed. Here we investigate image processing methods that perform the task of high-resolution image reconstruction, namely square-law detection, scaled subtraction, super-resolution SIM (SR-SIM), and Bayesian estimation. The optical sectioning and lateral resolution improvement abilities of these algorithms were tested under various noise level conditions on simulated data and on fluorescence microscopy images of a pollen grain test sample and of a cultured cell stained for the actin cytoskeleton. In order to compare the performance of the algorithms, the following objective criteria were evaluated: Signal to Noise Ratio (SNR), Signal to Background Ratio (SBR), circular average of the power spectral density and the S3 sharpness index. The results show that SR-SIM and Bayesian estimation combine illumination patterned images more effectively and provide better lateral resolution in exchange for more complex image processing. SR-SIM requires one to precisely shift the separated spectral components to their proper positions in reciprocal space. High noise levels in the raw data can cause inaccuracies in the shifts of the spectral components which degrade the super-resolved image. Bayesian estimation has proven to be more robust to changes in noise level and illumination pattern frequency.

  16. Functional Performance Testing After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Abrams, Geoffrey D.; Harris, Joshua D.; Gupta, Anil K.; McCormick, Frank M.; Bush-Joseph, Charles A.; Verma, Nikhil N.; Cole, Brian J.; Bach, Bernard R.

    2014-01-01

    Background: When to allow an athlete to return to unrestricted sporting activity after anterior cruciate ligament (ACL) reconstruction remains controversial. Purpose: To report the results of functional performance testing reported in the literature for individuals at differing time points following ACL reconstruction and to examine differences between graft types. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review of Medline, Scopus, and Cochrane Central Register of Controlled Trials was performed using PRISMA guidelines. Inclusion criteria were English-language studies that examined any functional rehabilitation test from 6 months to 2 years following ACL reconstruction. All patient-, limb-, and knee-specific demographics were extracted from included investigations. All functional rehabilitation tests were analyzed and compared when applicable. Results: The search term returned a total of 890 potential studies, with 88 meeting inclusion and exclusion criteria. A total of 4927 patients were included, of which 66% were male. The mean patient age was 26.5 ± 3.4 years. The predominant graft choices for reconstruction were bone–patellar tendon–bone (BPTB) autograft (59.8%) and hamstring autograft (37.9%). The most commonly reported functional tests were the hop tests. The results of these functional tests, as reported in the Limb Symmetry Index (LSI), improved with increasing time, with nearly all results greater than 90% at 1 year following primary ACL reconstruction. At 6 months postoperatively, a number of isokinetic strength measurements failed to reach 80% LSI, most commonly isokinetic knee extension testing in both BPTB and hamstring autograft groups. The knee flexion strength deficit was significantly less in the BPTB autograft group as compared with those having hamstring autograft at 1 year postoperatively, while no significant differences were found in isokinetic extension strength between the 2 groups. Conclusion: Hop

  17. Three-Dimensional Reconstruction from Cone-Beam Projections for Flat and Curved Detectors: Reconstruction Method Development.

    NASA Astrophysics Data System (ADS)

    Hu, Hui

    This dissertation is principally concerned with improving the performance of a prototype image-intensifier -based cone-beam volume computed tomography system by removing or partially removing two of its restricting factors, namely, the inaccuracy of current cone-beam reconstruction algorithm and the image distortion associated with the curved detecting surface of the image intensifier. To improve the accuracy of cone-beam reconstruction, first, the currently most accurate and computationally efficient cone-beam reconstruction method, the Feldkamp algorithm, is investigated by studying the relation of an original unknown function with its Feldkamp estimate. From this study, a partial knowledge on the unknown function can be derived in the Fourier domain from its Feldkamp estimate. Then, based on the Gerchberg-Papoulis algorithm, a modified iterative algorithm efficiently incorporating the Fourier knowledge as well as the a priori spatial knowledge on the unknown function is devised and tested to improve the cone-beam reconstruction accuracy by postprocessing the Feldkamp estimate. Two methods are developed to remove the distortion associated with the curved surface of image intensifier. A calibrating method based on a rubber-sheet remapping is designed and implemented. As an alternative, the curvature can be considered in the reconstruction algorithm. As an initial effort along this direction, a generalized convolution -backprojection reconstruction algorithm for fan-beam and any circular detector arrays is derived and studied.

  18. A CLASS OF RECONSTRUCTED DISCONTINUOUS GALERKIN METHODS IN COMPUTATIONAL FLUID DYNAMICS

    SciTech Connect

    Hong Luo; Yidong Xia; Robert Nourgaliev

    2011-05-01

    A class of reconstructed discontinuous Galerkin (DG) methods is presented to solve compressible flow problems on arbitrary grids. The idea is to combine the efficiency of the reconstruction methods in finite volume methods and the accuracy of the DG methods to obtain a better numerical algorithm in computational fluid dynamics. The beauty of the resulting reconstructed discontinuous Galerkin (RDG) methods is that they provide a unified formulation for both finite volume and DG methods, and contain both classical finite volume and standard DG methods as two special cases of the RDG methods, and thus allow for a direct efficiency comparison. Both Green-Gauss and least-squares reconstruction methods and a least-squares recovery method are presented to obtain a quadratic polynomial representation of the underlying linear discontinuous Galerkin solution on each cell via a so-called in-cell reconstruction process. The devised in-cell reconstruction is aimed to augment the accuracy of the discontinuous Galerkin method by increasing the order of the underlying polynomial solution. These three reconstructed discontinuous Galerkin methods are used to compute a variety of compressible flow problems on arbitrary meshes to assess their accuracy. The numerical experiments demonstrate that all three reconstructed discontinuous Galerkin methods can significantly improve the accuracy of the underlying second-order DG method, although the least-squares reconstructed DG method provides the best performance in terms of both accuracy, efficiency, and robustness.

  19. Contact Stress and Kinematic Analysis of All-Epiphyseal and Over-the-Top Pediatric Reconstruction Techniques for the Anterior Cruciate Ligament

    PubMed Central

    McCarthy, Moira M.; Tucker, Scott; Nguyen, Joseph T.; Green, Daniel W.; Imhauser, Carl W.; Cordasco, Frank A.

    2014-01-01

    Background Anterior cruciate ligament (ACL) injuries are an increasingly recognized problem in the pediatric population. Unfortunately, outcomes with conservative treatment are extremely poor. Furthermore, adult reconstruction techniques may be inappropriate to treat skeletally immature patients due to the risk of physeal complications. “Physeal-sparing” reconstruction techniques exist but their ability to restore knee stability and contact mechanics is not well understood. Purpose (1) To assess the ability of the all-epiphyseal (AE) and over-the-top (OT) reconstructions to restore knee kinematics; (2) to assess whether these reconstructions decrease the high posterior contact stresses seen with ACL deficiency; (3) to determine whether the AE or OT produce abnormal tibiofemoral contact stresses. Hypothesis The AE reconstruction will restore contact mechanics and kinematics similarly to that of the ACL intact knee. Methods Ten fresh-frozen human cadaveric knees were tested using a robotic manipulator. Tibiofemoral motions were recorded with the ACL intact, after sectioning the ACL, and after both reconstructions in each of the 10 specimens. The AE utilized an all-inside technique with tunnels exclusively within the epiphysis and fixed with suspensory cortical fixation devices. The OT had a central and vertical tibial tunnel with an over-the-top femur position and was fixed with staples and posts on both ends. Anterior stability was assessed with 134N anterior force at 0, 15, 30, 60, and 90° of knee flexion. Rotational stability was assessed with combined 8 Nm and 4 Nm of abduction and internal rotation, respectively, at 5, 15, and 30° of knee flexion. Results Both reconstruction techniques offloaded the posterior aspect of the tibial plateau compared to the ACL deficient knee in response to both anterior loads and combined moments as demonstrated by reduced contact stresses in this region at all flexion angles. Compared to the ACL intact condition, both the AE

  20. Prehospital ACLS--does it work?

    PubMed

    Maheshwari, Alok; Mehrotra, Avanti; Gupta, Anoop K; Thakur, Ranjan K

    2002-11-01

    Cardiac disease is the most common cause of death in the United States, and sudden cardiac arrest frequently claims the lives of men and women during their most productive years. It is believed that much better survival rates can be achieved for victims of cardiac arrest through optimizing the "chain of survival" as described by the American Heart Association. The relative and incremental benefit of full prehospital ACLS over basic life support and defibrillation is unproven, however. This is an important issue in this era of cost containment. Some of the ongoing studies including the OPALS study may clarify the cost effectiveness and relative efficacy of rapid defibrillation and full ACLS programs for victims of prehospital cardiac arrest [6].

  1. ACLED Country Report: Central African Republic

    DTIC Science & Technology

    2015-01-01

    violence between January 1997 and September 2014. Almost 8,000 fatalities have occurred during this time, making it the fourteenth most fatal country in...the dataset in this regard. However, violence has escalated sharply in recent years: the majority of these events occurred since the outbreak of the...CAR) is the fifteenth most violent country in the ACLED dataset, with over 2,000 recorded events of political violence between January 1997 and

  2. Rehabilitation After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Kruse, L.M.; Gray, B.; Wright, R.W.

    2012-01-01

    Background: Rigorous rehabilitation after anterior cruciate ligament (ACL) reconstruction is necessary for a successful surgical outcome. A large number of clinical trials continue to assess aspects of this rehabilitation process. Prior systematic reviews evaluated fifty-four Level-I and II clinical trials published through 2005. Methods: Eighty-five articles from 2006 to 2010 were identified utilizing multiple search engines. Twenty-nine Level-I or II studies met inclusion criteria and were evaluated with use of the CONSORT (Consolidated Standards of Reporting Trials) criteria. Topics included in this review are postoperative bracing, accelerated strengthening, home-based rehabilitation, proprioception and neuromuscular training, and six miscellaneous topics investigated in single trials. Results: Bracing following ACL reconstruction remains neither necessary nor beneficial and adds to the cost of the procedure. Early return to sports needs further research. Home-based rehabilitation can be successful. Although neuromuscular interventions are not likely to be harmful to patients, they are also not likely to yield large improvements in outcomes or help patients return to sports faster. Thus, they should not be performed to the exclusion of strengthening and range-of-motion exercises. Vibration training may lead to faster and more complete proprioceptive recovery but further evidence is needed. Conclusions: Several new modalities for rehabilitation after ACL reconstruction may be helpful but should not be performed to the exclusion of range-of-motion, strengthening, and functional exercises. Accelerated rehabilitation does not appear to be harmful but further investigation of rehabilitation timing is warranted. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence. PMID:23032584

  3. An iterative reconstruction method of complex images using expectation maximization for radial parallel MRI

    NASA Astrophysics Data System (ADS)

    Choi, Joonsung; Kim, Dongchan; Oh, Changhyun; Han, Yeji; Park, HyunWook

    2013-05-01

    In MRI (magnetic resonance imaging), signal sampling along a radial k-space trajectory is preferred in certain applications due to its distinct advantages such as robustness to motion, and the radial sampling can be beneficial for reconstruction algorithms such as parallel MRI (pMRI) due to the incoherency. For radial MRI, the image is usually reconstructed from projection data using analytic methods such as filtered back-projection or Fourier reconstruction after gridding. However, the quality of the reconstructed image from these analytic methods can be degraded when the number of acquired projection views is insufficient. In this paper, we propose a novel reconstruction method based on the expectation maximization (EM) method, where the EM algorithm is remodeled for MRI so that complex images can be reconstructed. Then, to optimize the proposed method for radial pMRI, a reconstruction method that uses coil sensitivity information of multichannel RF coils is formulated. Experiment results from synthetic and in vivo data show that the proposed method introduces better reconstructed images than the analytic methods, even from highly subsampled data, and provides monotonic convergence properties compared to the conjugate gradient based reconstruction method.

  4. Advanced Cardiac Life Support (ACLS) utilizing Man-Tended Capability (MTC) hardware onboard Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Smith, M.; Barratt, M.; Lloyd, C.

    1992-01-01

    Because of the time and distance involved in returning a patient from space to a definitive medical care facility, the capability for Advanced Cardiac Life Support (ACLS) exists onboard Space Station Freedom. Methods: In order to evaluate the effectiveness of terrestrial ACLS protocols in microgravity, a medical team conducted simulations during parabolic flights onboard the KC-135 aircraft. The hardware planned for use during the MTC phase of the space station was utilized to increase the fidelity of the scenario and to evaluate the prototype equipment. Based on initial KC-135 testing of CPR and ACLS, changes were made to the ventricular fibrillation algorithm in order to accommodate the space environment. Other constraints to delivery of ACLS onboard the space station include crew size, minimum training, crew deconditioning, and limited supplies and equipment. Results: The delivery of ACLS in microgravity is hindered by the environment, but should be adequate. Factors specific to microgravity were identified for inclusion in the protocol including immediate restraint of the patient and early intubation to insure airway. External cardiac compressions of adequate force and frequency were administered using various methods. The more significant limiting factors appear to be crew training, crew size, and limited supplies. Conclusions: Although ACLS is possible in the microgravity environment, future evaluations are necessary to further refine the protocols. Proper patient and medical officer restraint is crucial prior to advanced procedures. Also emphasis should be placed on early intubation for airway management and drug administration. Preliminary results and further testing will be utilized in the design of medical hardware, determination of crew training, and medical operations for space station and beyond.

  5. Method of Breast Reconstruction Determines Venous Thromboembolism Risk Better Than Current Prediction Models

    PubMed Central

    Patel, Niyant V.; Wagner, Douglas S.

    2015-01-01

    Background: Venous thromboembolism (VTE) risk models including the Davison risk score and the 2005 Caprini risk assessment model have been validated in plastic surgery patients. However, their utility and predictive value in breast reconstruction has not been well described. We sought to determine the utility of current VTE risk models in this population and the VTE rate observed in various methods of breast reconstruction. Methods: A retrospective review of breast reconstructions by a single surgeon was performed. One hundred consecutive transverse rectus abdominis myocutaneous (TRAM) patients, 100 consecutive implant patients, and 100 consecutive latissimus dorsi patients were identified over a 10-year period. Patient demographics and presence of symptomatic VTE were collected. 2005 Caprini risk scores and Davison risk scores were calculated for each patient. Results: The TRAM reconstruction group was found to have a higher VTE rate (6%) than the implant (0%) and latissimus (0%) reconstruction groups (P < 0.01). Mean Davison risk scores and 2005 Caprini scores were similar across all reconstruction groups (P > 0.1). The vast majority of patients were stratified as high risk (87.3%) by the VTE risk models. However, only TRAM reconstruction patients demonstrated significant VTE risk. Conclusions: TRAM reconstruction appears to have a significantly higher risk of VTE than both implant and latissimus reconstruction. Current risk models do not effectively stratify breast reconstruction patients at risk for VTE. The method of breast reconstruction appears to have a significant role in patients’ VTE risk. PMID:26090287

  6. Thermography based diagnosis of ruptured anterior cruciate ligament (ACL) in canines

    NASA Astrophysics Data System (ADS)

    Lama, Norsang; Umbaugh, Scott E.; Mishra, Deependra; Dahal, Rohini; Marino, Dominic J.; Sackman, Joseph

    2016-09-01

    Anterior cruciate ligament (ACL) rupture in canines is a common orthopedic injury in veterinary medicine. Veterinarians use both imaging and non-imaging methods to diagnose the disease. Common imaging methods such as radiography, computed tomography (CT scan) and magnetic resonance imaging (MRI) have some disadvantages: expensive setup, high dose of radiation, and time-consuming. In this paper, we present an alternative diagnostic method based on feature extraction and pattern classification (FEPC) to diagnose abnormal patterns in ACL thermograms. The proposed method was experimented with a total of 30 thermograms for each camera view (anterior, lateral and posterior) including 14 disease and 16 non-disease cases provided from Long Island Veterinary Specialists. The normal and abnormal patterns in thermograms are analyzed in two steps: feature extraction and pattern classification. Texture features based on gray level co-occurrence matrices (GLCM), histogram features and spectral features are extracted from the color normalized thermograms and the computed feature vectors are applied to Nearest Neighbor (NN) classifier, K-Nearest Neighbor (KNN) classifier and Support Vector Machine (SVM) classifier with leave-one-out validation method. The algorithm gives the best classification success rate of 86.67% with a sensitivity of 85.71% and a specificity of 87.5% in ACL rupture detection using NN classifier for the lateral view and Norm-RGB-Lum color normalization method. Our results show that the proposed method has the potential to detect ACL rupture in canines.

  7. Simultaneous segmentation and reconstruction: A level set method approach for limited view computed tomography

    PubMed Central

    Yoon, Sungwon; Pineda, Angel R.; Fahrig, Rebecca

    2010-01-01

    Purpose: An iterative tomographic reconstruction algorithm that simultaneously segments and reconstructs the reconstruction domain is proposed and applied to tomographic reconstructions from a sparse number of projection images. Methods: The proposed algorithm uses a two-phase level set method segmentation in conjunction with an iterative tomographic reconstruction to achieve simultaneous segmentation and reconstruction. The simultaneous segmentation and reconstruction is achieved by alternating between level set function evolutions and per-region intensity value updates. To deal with the limited number of projections, a priori information about the reconstruction is enforced via penalized likelihood function. Specifically, smooth function within each region (piecewise smooth function) and bounded function intensity values for each region are assumed. Such a priori information is formulated into a quadratic objective function with linear bound constraints. The level set function evolutions are achieved by artificially time evolving the level set function in the negative gradient direction; the intensity value updates are achieved by using the gradient projection conjugate gradient algorithm. Results: The proposed simultaneous segmentation and reconstruction results were compared to “conventional” iterative reconstruction (with no segmentation), iterative reconstruction followed by segmentation, and filtered backprojection. Improvements of 6%–13% in the normalized root mean square error were observed when the proposed algorithm was applied to simulated projections of a numerical phantom and to real fan-beam projections of the Catphan phantom, both of which did not satisfy the a priori assumptions. Conclusions: The proposed simultaneous segmentation and reconstruction resulted in improved reconstruction image quality. The algorithm correctly segments the reconstruction space into regions, preserves sharp edges between different regions, and smoothes the noise

  8. Simultaneous segmentation and reconstruction: A level set method approach for limited view computed tomography

    SciTech Connect

    Yoon, Sungwon; Pineda, Angel R.; Fahrig, Rebecca

    2010-05-15

    Purpose: An iterative tomographic reconstruction algorithm that simultaneously segments and reconstructs the reconstruction domain is proposed and applied to tomographic reconstructions from a sparse number of projection images. Methods: The proposed algorithm uses a two-phase level set method segmentation in conjunction with an iterative tomographic reconstruction to achieve simultaneous segmentation and reconstruction. The simultaneous segmentation and reconstruction is achieved by alternating between level set function evolutions and per-region intensity value updates. To deal with the limited number of projections, a priori information about the reconstruction is enforced via penalized likelihood function. Specifically, smooth function within each region (piecewise smooth function) and bounded function intensity values for each region are assumed. Such a priori information is formulated into a quadratic objective function with linear bound constraints. The level set function evolutions are achieved by artificially time evolving the level set function in the negative gradient direction; the intensity value updates are achieved by using the gradient projection conjugate gradient algorithm. Results: The proposed simultaneous segmentation and reconstruction results were compared to ''conventional'' iterative reconstruction (with no segmentation), iterative reconstruction followed by segmentation, and filtered backprojection. Improvements of 6%-13% in the normalized root mean square error were observed when the proposed algorithm was applied to simulated projections of a numerical phantom and to real fan-beam projections of the Catphan phantom, both of which did not satisfy the a priori assumptions. Conclusions: The proposed simultaneous segmentation and reconstruction resulted in improved reconstruction image quality. The algorithm correctly segments the reconstruction space into regions, preserves sharp edges between different regions, and smoothes the noise

  9. Should critical care nurses be ACLS-trained?

    PubMed

    Hagyard-Wiebe, Tammy

    2007-01-01

    The aim of resuscitation is to sustain life with intact neurological functioning and the same quality of life previously experienced by the patient. Advanced cardiac life support (ACLS) was designed to achieve this aim. However the requirement for ACLS training for critical care nurses working in Canadian critical care units is inconsistent across the country. The purposes of this article are to explore the evidence surrounding ACLS training for critical care nurses and its impact on resuscitation outcomes, and to review the evidence surrounding ACLS knowledge and skill degradation with strategies to support code blue team efficiency for an effective resuscitation. Using the search terms ACLS training, resuscitation, critical care, and nursing, two databases, CINAHL and MEDLINE, were used. The evidence supports the need for ACLS training for critical care nurses. The evidence also supports organized ongoing refresher courses, multidisciplinary mock code blue practice using technologically advanced simulator mannequins, and videotaped reviews to prevent knowledge and skill degradation for effective resuscitation efforts.

  10. New method to analyze internal disruptions with tomographic reconstructions

    NASA Astrophysics Data System (ADS)

    Tanzi, C. P.; de Blank, H. J.

    1997-03-01

    Sawtooth crashes have been investigated on the Rijnhuizen Tokamak Project (RTP) [N. J. Lopes Cardozo et al., Proceedings of the 14th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Würzburg, 1992 (International Atomic Energy Agency, Vienna, 1993), Vol. 1, p. 271]. Internal disruptions in tokamak plasmas often exhibit an m=1 poloidal mode structure prior to the collapse which can be clearly identified by means of multicamera soft x-ray diagnostics. In this paper tomographic reconstructions of such m=1 modes are analyzed with a new method, based on magnetohydrodynamic (MHD) invariants computed from the two-dimensional emissivity profiles, which quantifies the amount of profile flattening not only after the crash but also during the precursor oscillations. The results are interpreted by comparing them with two models which simulate the measurements of the m=1 redistribution of soft x-ray emissivity prior to the sawtooth crash. One model is based on the magnetic reconnection model of Kadomtsev. The other involves ideal MHD motion only. In cases where differences in magnetic topology between the two models cannot be seen in the tomograms, the analysis of profile flattening has an advantage. The analysis shows that in RTP the clearly observed m=1 displacement of some sawteeth requires the presence of convective ideal MHD motion, whereas other precursors are consistent with magnetic reconnection of up to 75% of the magnetic flux within the q=1 surface. The possibility of ideal interchange combined with enhanced cross-field transport is not excluded.

  11. Evaluation of a 3D point cloud tetrahedral tomographic reconstruction method

    PubMed Central

    Pereira, N F; Sitek, A

    2011-01-01

    Tomographic reconstruction on an irregular grid may be superior to reconstruction on a regular grid. This is achieved through an appropriate choice of the image space model, the selection of an optimal set of points and the use of any available prior information during the reconstruction process. Accordingly, a number of reconstruction-related parameters must be optimized for best performance. In this work, a 3D point cloud tetrahedral mesh reconstruction method is evaluated for quantitative tasks. A linear image model is employed to obtain the reconstruction system matrix and five point generation strategies are studied. The evaluation is performed using the recovery coefficient, as well as voxel- and template-based estimates of bias and variance measures, computed over specific regions in the reconstructed image. A similar analysis is performed for regular grid reconstructions that use voxel basis functions. The maximum likelihood expectation maximization reconstruction algorithm is used. For the tetrahedral reconstructions, of the five point generation methods that are evaluated, three use image priors. For evaluation purposes, an object consisting of overlapping spheres with varying activity is simulated. The exact parallel projection data of this object are obtained analytically using a parallel projector, and multiple Poisson noise realizations of these exact data are generated and reconstructed using the different point generation strategies. The unconstrained nature of point placement in some of the irregular mesh-based reconstruction strategies has superior activity recovery for small, low-contrast image regions. The results show that, with an appropriately generated set of mesh points, the irregular grid reconstruction methods can out-perform reconstructions on a regular grid for mathematical phantoms, in terms of the performance measures evaluated. PMID:20736496

  12. Kinesiophobia After Anterior Cruciate Ligament Rupture and Reconstruction: Noncopers Versus Potential Copers

    PubMed Central

    Hartigan, Erin H.; Lynch, Andrew D.; Logerstedt, David S.; Chmielewski, Terese L.; Snyder-Mackler, Lynn

    2016-01-01

    STUDY DESIGN Secondary-analysis, longitudinal cohort study. OBJECTIVES To compare kinesiophobia levels in noncopers and potential copers at time points spanning pre– and post–anterior cruciate ligament (ACL) reconstruction and to examine the association between changes in kinesiophobia levels and clinical measures. BACKGROUND After ACL injury, a screening examination may be used to classify patients as potential copers or noncopers based on dynamic knee stability. Quadriceps strength, single-leg hop performance, and self-reported knee function are worse in noncopers. High kinesiophobia levels after ACL reconstruction are associated with poorer self-reported knee function and lower return-to-sport rates. Kinesiophobia levels have not been examined before ACL reconstruction, across the transition from presurgery to postsurgery, or based on potential coper and noncoper classification. METHODS Quadriceps strength indexes, single-leg hop score indexes, self-reported knee function (Knee Outcome Survey activities of daily living subscale, global rating scale), and kinesiophobia (Tampa Scale of Kinesiophobia [TSK-11]) scores were compiled for potential copers (n = 50) and noncopers (n = 61) from 2 clinical trial databases. A repeated-measures analysis of variance was used to compare TSK-11 scores between groups and across 4 time points (before preoperative treatment, after preoperative treatment, 6 months post–ACL reconstruction, and 12 months post–ACL reconstruction). Correlations determined the association of kinesiophobia levels with other clinical measures. RESULTS Presurgery TSK-11 scores were significantly higher in noncopers than in potential copers. Postsurgery, no group differences existed. TSK-11 scores in both groups decreased across all time points; however, TSK-11 scores decreased more in noncopers in the interval between presurgery and postsurgery. In noncopers, the decreases in TSK-11 scores from presurgery to postsurgery and after surgery were

  13. Reduction and reconstruction methods for simulation and control of fluids

    NASA Astrophysics Data System (ADS)

    Ma, Zhanhua

    In this thesis we develop model reduction/reconstruction methods that are applied to simulation and control of fluids. In the first part of the thesis, we focus on development of dimension reduction methods that compute reduced-order models (at the order of 101˜2) of systems with high-dimensional states (at the order of 105˜8) that are typical in computational fluid dynamics. The reduced-order models are then used for feedback control design for the full systems, as the control design tools are usually applicable only to systems of order up to 10 4. First, we show that a widely-used model reduction method for stable linear timeinvariant (LTI) systems, the approximate balanced truncation method (also called balanced POD), yields identical reduced-order models as Eigensystem Realization Algorithm (ERA), a well-known method in system identification. Unlike ERA, Balanced POD generates sets of modes that are useful in controller/observer design and systems analysis. On the other hand, ERA is more computationally efficient and does not need data from adjoint systems, which cannot be constructed in experiments and are often costly to construct and simulate numerically. The equivalence of ERA and balanced POD leads us to further design a version of ERA that works for unstable (linear) systems with one-dimensional unstable eigenspace and is equivalent to a recently developed version of balanced POD for unstable systems. We consider further generalization of balanced POD/ERA methods for linearized time-periodic systems around an unstable orbit. Four algorithms are presented: the lifted balanced POD/lifted ERA and the periodic balanced POD/periodic ERA. The lifting approach generates a LTI reduced-order model that updates the system once every period, and the periodic approach generates a periodic reduced-order model. By construction the lifted ERA is the most computationally efficient algorithm and it does not need adjoint data. By removing periodicity in periodic balanced

  14. Comparison of methods for the reduction of reconstructed layers in atmospheric tomography.

    PubMed

    Saxenhuber, Daniela; Auzinger, Günter; Louarn, Miska Le; Helin, Tapio

    2017-04-01

    For the new generation of extremely large telescopes (ELTs), the computational effort for adaptive optics (AO) systems is demanding even for fast reconstruction algorithms. In wide-field AO, atmospheric tomography, i.e., the reconstruction of turbulent atmospheric layers from wavefront sensor data in several directions of view, is the crucial step for an overall reconstruction. Along with the number of deformable mirrors, wavefront sensors and their resolution, as well as the guide star separation, the number of reconstruction layers contributes significantly to the numerical effort. To reduce the computational cost, a sparse reconstruction profile which still yields good reconstruction quality is needed. In this paper, we analyze existing methods and present new approaches to determine optimal layer heights and turbulence weights for the tomographic reconstruction. Two classes of methods are discussed. On the one hand, we have compression methods that downsample a given input profile to fewer layers. Among other methods, a new compression method based on discrete optimization of collecting atmospheric layers to subgroups and the compression by means of conserving turbulence moments is presented. On the other hand, we take a look at a joint optimization of tomographic reconstruction and reconstruction profile during atmospheric tomography, which is independent of any a priori information on the underlying input profile. We analyze and study the qualitative performance of these methods for different input profiles and varying fields of view in an ELT-sized multi-object AO setting on the European Southern Observatory end-to-end simulation tool OCTOPUS.

  15. Reconstruction method of compressed sensing for remote sensing images cooperating with energy compensation

    NASA Astrophysics Data System (ADS)

    He, Jinping; Ruan, Ningjuan; Zhao, Haibo; Liu, Yuchen

    2016-10-01

    Remote sensing features are varied and complicated. There is no comprehensive coverage dictionary for reconstruction. The reconstruction precision is not guaranteed. Aiming at the above problems, a novel reconstruction method with multiple compressed sensing data based on energy compensation is proposed in this paper. The multiple measured data and multiple coding matrices compose the reconstruction equation. It is locally solved through the Orthogonal Matching Pursuit (OMP) algorithm. Then the initial reconstruction image is obtained. Further assuming the local image patches have the same compensation gray value, the mathematical model of compensation value is constructed by minimizing the error of multiple estimated measured values and actual measured values. After solving the minimization, the compensation values are added to the initial reconstruction image. Then the final energy compensation image is obtained. The experiments prove that the energy compensation method is superior to those without compensation. Our method is more suitable for remote sensing features.

  16. LARS Artificial Ligament Versus ABC Purely Polyester Ligament for Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Iliadis, Dimitrios Ph.; Bourlos, Dimitrios N.; Mastrokalos, Dimitrios S.; Chronopoulos, Efstathios; Babis, George C.

    2016-01-01

    Background: Graft choice for anterior cruciate ligament (ACL) reconstruction is of critical importance. Various grafts have been used so far, with autografts long considered the optimal solution for the treatment of ACL-deficient knees. Limited data are available on the long-term survivorship of synthetic grafts. Purpose: To compare the functional outcome and survivorship of ACL reconstructions performed using the LARS (ligament augmentation and reconstruction system) ligament and the ABC (active biosynthetic composite) purely polyester ligament. Study Design: Case series; Level of evidence, 4. Methods: The results of 72 patients who underwent primary arthroscopic ACL reconstruction with the LARS ligament and 31 cases with an ABC purely polyester ligament were reviewed. The mean follow-up periods for the LARS and ABC groups were 9.5 and 5.1 years, respectively. A survivorship analysis of the 2 synthetic grafts was performed using the Kaplan-Meier method with a log-rank test (Mantel-Cox, 95% CI). Lysholm, Tegner activity, Knee injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) scores as well as laxity measurements obtained using a KT-1000 arthrometer were recorded for all intact grafts, and a Mann-Whitney U test was used for comparison reasons. Results: The rupture rates for LARS and ABC grafts were 31% (95% CI, 20%-42%) and 42% (95% CI, 25%-59%), respectively. For intact grafts, the mean Lysholm score was good for both groups (90 for the LARS group and 89 for the ABC group), with the majority of patients returning to their preinjury level of activities, and the mean IKDC score was 90 for the LARS group and 86 for the ABC group. Conclusion: The rupture rates of both LARS and ABC grafts were both high. However, the LARS ligament provided significantly better survivorship compared with the ABC ligament at short- to midterm follow-up (95% CI). PMID:27453894

  17. A novel method for the 3-D reconstruction of scoliotic ribs from frontal and lateral radiographs.

    PubMed

    Seoud, Lama; Cheriet, Farida; Labelle, Hubert; Dansereau, Jean

    2011-05-01

    Among the external manifestations of scoliosis, the rib hump, which is associated with the ribs' deformities and rotations, constitutes the most disturbing aspect of the scoliotic deformity for patients. A personalized 3-D model of the rib cage is important for a better evaluation of the deformity, and hence, a better treatment planning. A novel method for the 3-D reconstruction of the rib cage, based only on two standard radiographs, is proposed in this paper. For each rib, two points are extrapolated from the reconstructed spine, and three points are reconstructed by stereo radiography. The reconstruction is then refined using a surface approximation. The method was evaluated using clinical data of 13 patients with scoliosis. A comparison was conducted between the reconstructions obtained with the proposed method and those obtained by using a previous reconstruction method based on two frontal radiographs. A first comparison criterion was the distances between the reconstructed ribs and the surface topography of the trunk, considered as the reference modality. The correlation between ribs axial rotation and back surface rotation was also evaluated. The proposed method successfully reconstructed the ribs of the 6th-12th thoracic levels. The evaluation results showed that the 3-D configuration of the new rib reconstructions is more consistent with the surface topography and provides more accurate measurements of ribs axial rotation.

  18. Effects of electrical and electromagnetic stimulation after anterior cruciate ligament reconstruction.

    PubMed

    Currier, D P; Ray, J M; Nyland, J; Rooney, J G; Noteboom, J T; Kellogg, R

    1993-04-01

    A need exists to develop new methods of neuromuscular electrical stimulation (NMES) that are both effective and relatively pain-free. The purpose of this pilot study was to determine the effects of both NMES and a new method of electromagnetic (NMES/PEMF) stimulation for reducing girth loss and for reducing pain and muscle weakness of the knee extensor muscles in patients during the first 6 weeks after reconstructive surgery of the anterior cruciate ligament (ACL). Seventeen patients receiving ACL reconstructive surgery participated as a control group (N = 3), as an NMES group (N = 7), and with combined NMES and magnetic field stimulation (NMES/PEMF) (N = 7). Patients receiving NMES/PEMF rated each type of stimulation for perceived pain and were measured for their torque. Torque results revealed a mean decrease of 13.1% for NMES/PEMF patients. The mean percent of thigh girth decreased 8.3% for controls, 0.5% for NMES, and 2.3% for NMES/PEMF patients. The NMES/PEMF patients rated NMES as causing about twice the pain intensity as NMES/PEMF during treatments. As a result of this data, the authors conclude that both NMES and NMES/PEMF are effective in reducing girth loss and that NMES/PEMF is less painful than NMES alone in treating patients after ACL reconstruction.

  19. Return to Sports after Acute Simultaneous Reconstruction of Anterior Cruciate Ligament Injury and Grade III Medial Collateral Ligament Injury

    PubMed Central

    Bertona, Agustin; Zicaro, Juan Pablo; Viescas, Juan Manuel Gonzalez; Atala, Nicolas; Yacuzzi, Carlos; Costa-Paz, Matias

    2017-01-01

    Objectives: Combined Anterior Cruciate Ligament (ACL) injury and Medial Collateral Ligament (MCL) injury account for 20% of knee ligament lesions. Conservative treatment of MCL and surgical ACL reconstruction are generally recommended. Significant medial instability after non-surgical management of MCL can lead to ACL reconstruction failure. The optimal management for athletes with combined ACL-MCL injuries remains controversial. The purpose of this study was to analyze the functional and clinical evolution of patients who underwent combined ACL-MCL surgery and their return-to-sport level with minimum 2-years follow-up. Methods: A total of 20 athletes with acute simultaneous ACL/Grade III MCL reconstructions were treated between March 2006 and January 2014. The minimum follow-up time was 24 months. Subjective functional results (IKDC, Lysholm), range of motion, anterior-medial and rotational stability (Lachmann, Pivot Shift, valgus stress) were evaluated. The ability to return to sport (Tegner) and the level achieved was recorded. Results: All patients significantly improved functional scores and stability tests. The mean subjective IKDC score improved from 37.7 ± 12.9 (range 21-69) preoperatively to 88.21 ± 4.47 (range 80-96) postoperatively (P <0.05). The average Lysholm score was 40.44 ± 10.58 (range 27-65) preoperatively and 90.83 ± 3.38 (range 84-95) postoperatively (P <0.05). Valgus and sagittal laxity was not observed (IKDC A 92% B 8%) at final follow-up. All patients had normal/nearly normal (IKDC A or B) mobility. All patients returned to sports; 90% reached the level they had prior to the ligamentous injury. Of all competitive athletes, 66% achieved the same level of sport. Conclusion: In athletes with acute ACL-Grade III MCL lesions, an early simultaneous reconstruction can significantly improve the medial and sagittal stability of the knee. This procedure resulted in excellent functional outcomes, with return to the same level of sports in the

  20. Exploring Normalization and Network Reconstruction Methods using In Silico and In Vivo Models

    EPA Science Inventory

    Abstract: Lessons learned from the recent DREAM competitions include: The search for the best network reconstruction method continues, and we need more complete datasets with ground truth from more complex organisms. It has become obvious that the network reconstruction methods t...

  1. Stepwise method based on Wiener estimation for spectral reconstruction in spectroscopic Raman imaging.

    PubMed

    Chen, Shuo; Wang, Gang; Cui, Xiaoyu; Liu, Quan

    2017-01-23

    Raman spectroscopy has demonstrated great potential in biomedical applications. However, spectroscopic Raman imaging is limited in the investigation of fast changing phenomena because of slow data acquisition. Our previous studies have indicated that spectroscopic Raman imaging can be significantly sped up using the approach of narrow-band imaging followed by spectral reconstruction. A multi-channel system was built to demonstrate the feasibility of fast wide-field spectroscopic Raman imaging using the approach of simultaneous narrow-band image acquisition followed by spectral reconstruction based on Wiener estimation in phantoms. To further improve the accuracy of reconstructed Raman spectra, we propose a stepwise spectral reconstruction method in this study, which can be combined with the earlier developed sequential weighted Wiener estimation to improve spectral reconstruction accuracy. The stepwise spectral reconstruction method first reconstructs the fluorescence background spectrum from narrow-band measurements and then the pure Raman narrow-band measurements can be estimated by subtracting the estimated fluorescence background from the overall narrow-band measurements. Thereafter, the pure Raman spectrum can be reconstructed from the estimated pure Raman narrow-band measurements. The result indicates that the stepwise spectral reconstruction method can improve spectral reconstruction accuracy significantly when combined with sequential weighted Wiener estimation, compared with the traditional Wiener estimation. In addition, qualitatively accurate cell Raman spectra were successfully reconstructed using the stepwise spectral reconstruction method from the narrow-band measurements acquired by a four-channel wide-field Raman spectroscopic imaging system. This method can potentially facilitate the adoption of spectroscopic Raman imaging to the investigation of fast changing phenomena.

  2. New method to analyze internal disruptions with tomographic reconstructions

    SciTech Connect

    Tanzi, C.P.; de Blank, H.J.

    1997-03-01

    Sawtooth crashes have been investigated on the Rijnhuizen Tokamak Project (RTP) [N. J. Lopes Cardozo {ital et al.}, {ital Proceedings of the 14th International Conference on Plasma Physics and Controlled Nuclear Fusion Research}, W{umlt u}rzburg, 1992 (International Atomic Energy Agency, Vienna, 1993), Vol. 1, p. 271]. Internal disruptions in tokamak plasmas often exhibit an m=1 poloidal mode structure prior to the collapse which can be clearly identified by means of multicamera soft x-ray diagnostics. In this paper tomographic reconstructions of such m=1 modes are analyzed with a new method, based on magnetohydrodynamic (MHD) invariants computed from the two-dimensional emissivity profiles, which quantifies the amount of profile flattening not only after the crash but also during the precursor oscillations. The results are interpreted by comparing them with two models which simulate the measurements of the m=1 redistribution of soft x-ray emissivity prior to the sawtooth crash. One model is based on the magnetic reconnection model of Kadomtsev. The other involves ideal MHD motion only. In cases where differences in magnetic topology between the two models cannot be seen in the tomograms, the analysis of profile flattening has an advantage. The analysis shows that in RTP the clearly observed m=1 displacement of some sawteeth requires the presence of convective ideal MHD motion, whereas other precursors are consistent with magnetic reconnection of up to 75{percent} of the magnetic flux within the q=1 surface. The possibility of ideal interchange combined with enhanced cross-field transport is not excluded. {copyright} {ital 1997 American Institute of Physics.}

  3. On multigrid methods for image reconstruction from projections

    SciTech Connect

    Henson, V.E.; Robinson, B.T.; Limber, M.

    1994-12-31

    The sampled Radon transform of a 2D function can be represented as a continuous linear map R : L{sup 1} {yields} R{sup N}. The image reconstruction problem is: given a vector b {element_of} R{sup N}, find an image (or density function) u(x, y) such that Ru = b. Since in general there are infinitely many solutions, the authors pick the solution with minimal 2-norm. Numerous proposals have been made regarding how best to discretize this problem. One can, for example, select a set of functions {phi}{sub j} that span a particular subspace {Omega} {contained_in} L{sup 1}, and model R : {Omega} {yields} R{sup N}. The subspace {Omega} may be chosen as a member of a sequence of subspaces whose limit is dense in L{sup 1}. One approach to the choice of {Omega} gives rise to a natural pixel discretization of the image space. Two possible choices of the set {phi}{sub j} are the set of characteristic functions of finite-width `strips` representing energy transmission paths and the set of intersections of such strips. The authors have studied the eigenstructure of the matrices B resulting from these choices and the effect of applying a Gauss-Seidel iteration to the problem Bw = b. There exists a near null space into which the error vectors migrate with iteration, after which Gauss-Seidel iteration stalls. The authors attempt to accelerate convergence via a multilevel scheme, based on the principles of McCormick`s Multilevel Projection Method (PML). Coarsening is achieved by thickening the rays which results in a much smaller discretization of an optimal grid, and a halving of the number of variables. This approach satisfies all the requirements of the PML scheme. They have observed that a multilevel approach based on this idea accelerates convergence at least to the point where noise in the data dominates.

  4. Reconstruction method for data protection in telemedicine systems

    NASA Astrophysics Data System (ADS)

    Buldakova, T. I.; Suyatinov, S. I.

    2015-03-01

    In the report the approach to protection of transmitted data by creation of pair symmetric keys for the sensor and the receiver is offered. Since biosignals are unique for each person, their corresponding processing allows to receive necessary information for creation of cryptographic keys. Processing is based on reconstruction of the mathematical model generating time series that are diagnostically equivalent to initial biosignals. Information about the model is transmitted to the receiver, where the restoration of physiological time series is performed using the reconstructed model. Thus, information about structure and parameters of biosystem model received in the reconstruction process can be used not only for its diagnostics, but also for protection of transmitted data in telemedicine complexes.

  5. Tibiofemoral cartilage contact biomechanics in patients after reconstruction of a ruptured anterior cruciate ligament.

    PubMed

    Hosseini, Ali; Van de Velde, Samuel; Gill, Thomas J; Li, Guoan

    2012-11-01

    We investigated the in vivo cartilage contact biomechanics of the tibiofemoral joint in patients after reconstruction of a ruptured anterior cruciate ligament (ACL). A dual fluoroscopic and MR imaging technique was used to investigate the cartilage contact biomechanics of the tibiofemoral joint during in vivo weight-bearing flexion of the knee in eight patients 6 months following clinically successful reconstruction of an acute isolated ACL rupture. The location of tibiofemoral cartilage contact, size of the contact area, cartilage thickness at the contact area, and magnitude of the cartilage contact deformation of the ACL-reconstructed knees were compared with those previously measured in intact (contralateral) knees and ACL-deficient knees of the same subjects. Contact biomechanics of the tibiofemoral cartilage after ACL reconstruction were similar to those measured in intact knees. However, at lower flexion, the abnormal posterior and lateral shift of cartilage contact location to smaller regions of thinner tibial cartilage that has been described in ACL-deficient knees persisted in ACL-reconstructed knees, resulting in an increase of the magnitude of cartilage contact deformation at those flexion angles. Reconstruction of the ACL restored some of the in vivo cartilage contact biomechanics of the tibiofemoral joint to normal. Clinically, recovering anterior knee stability might be insufficient to prevent post-operative cartilage degeneration due to lack of restoration of in vivo cartilage contact biomechanics.

  6. Tibial plateau fracture following gracilis-semitendinosus anterior cruciate ligament reconstruction: The tibial tunnel stress-riser.

    PubMed

    Sundaram, R O; Cohen, D; Barton-Hanson, N

    2006-06-01

    Tibial plateau fractures following anterior cruciate ligament (ACL) reconstruction are extremely rare. This is the first reported case of a tibial plateau fracture following four-strand gracilis-semitendinosus autograft ACL reconstruction. The tibial tunnel alone may behave as a stress riser which can significantly reduce bone strength.

  7. Comparing Transtibial and Anteromedial Drilling Techniques for Single-bundle Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Sukur, Erhan; Akman, , Yunus Emre; Senel, , Ahmet; Unkar, Ethem Ayhan; Topcu, , Huseyin Nevzat; Ozturkmen, , and Yusuf

    2016-01-01

    Background: Among the many factors that determine the outcome following anterior cruciate ligament (ACL) reconstruction, the position of the femoral tunnel is known to be critically important and is still the subject of extensive research. Objective: We aimed to retrospectively compare the outcomes of arthroscopic ACL reconstruction using transtibial (TT) or anteromedial (AMP) drilling techniques for femoral tunnel placement. Methods: ACL reconstruction was performed using the TT technique in 49 patients and the AMP technique in 56 patients. Lachman and pivot-shift tests, the Lysholm Knee Scale, International Knee Documentation Committee (IKDC) score, Tegner activity scale and visual analog scale (VAS) were used for the clinical and functional evaluation of patients. Time to return to normal life and time to jogging were assessed in addition to the radiological evaluation of femoral tunnel placement. Results: In terms of the Lysholm, IKDC, Tegner score, and stability tests, no significant differences were found between the two groups (p > 0.05). Statistical analysis revealed reduced time to return to normal life and jogging in the AMP group (p < 0.05). The VAS score was also significantly reduced in the AMP group (p < 0.05). The position of the femoral tunnel was anatomically appropriate in 51 patients in the AMP group and 5 patients in the TT group. Conclusion: The AMP technique is superior to the TT technique in creating anatomical femoral tunnel placement during single-bundle ACL reconstruction and provides faster recovery in terms of return to normal life and jogging at short-term follow-up. PMID:27733884

  8. Returning to sport after anterior cruciate ligament reconstruction in amateur sports men: a retrospective study

    PubMed Central

    Notarnicola, Angela; Maccagnano, Giuseppe; Barletta, Federico; Ascatigno, Leonardo; Astuto, Leopoldo; Panella, Antonio; Tafuri, Silvio; Moretti, Biagio

    2016-01-01

    Summary Background According to the literature, 95% of professional athletes return to their sport after anterior cruciate ligament (ACL) reconstruction surgery. The main objective of this study was to verify the return to sport after ACL reconstruction in a homogenous group of amateur sportsmen and sportswomen in a series of Italian patients. Materials and methods We designed a retrospective study in which we analyzed the amateur sports patients operated for ACL reconstruction. We verified whether they had returned to sporting activities by comparing the pre- and post-operative Tegner activity scores. We then analyzed the average time to restart the sporting activity and the Lysholm and International Knee Documenting Committee (IKDC) scores. Results We analyzed 80 subjects: 47.5% restarted a sports activity, on average after eight months, with a significant reduction of their competitive level or physical commitment, as expressed by the Tegner activity score (pre-operative: 6.9; post-operative: 3.9; p<0.01). The functional knee recovery was good, as expressed by the average score of the Lyshom Knee Scoring Scale (93.5) and the IKDC (74.7). Conclusions In the literature, a return to sport for international case studies and amateur sports is higher than our data. In our population we found the lack of information provided by the medical staff at discharge and follow-up. The assessment at a short-term follow up allowed us to verify that at the end of the post-surgical rehabilitation program the patients were uninformed about the timing and the ability to resume a sporting activity. An efficacious relationship between orthopedic doctor, physiotherapist and a doctor in motorial science may ensure proper treatment the patient after ACL reconstruction. It is important to guarantee the restarting of the sports activity to have a better quality of life in amateur sports. Level of evidence: V. PMID:28217571

  9. Mid-Term Outcomes of Anterior Cruciate Ligament Reconstruction with Far Anteromedial Portal Technique

    PubMed Central

    Jeon, Yoon Sang; Choi, Sung Wook; Park, Ju Hyun; Yoon, Jae Sik; Shin, Jung Sub; Kim, Myung Ku

    2017-01-01

    Purpose The purpose of this study was to evaluate the mid-term outcomes of anatomic anterior cruciate ligament (ACL) reconstruction using two anteromedial (AM) portals by comparing with short-term follow-up results. Materials and Methods Fifty patients who were treated by ACL reconstruction using a two AM portal technique were evaluated retrospectively. The follow-up period was at least 5 years. The mean follow-up period was 68.5±13.9 months. The mid-term clinical outcomes were compared with short-term (≥12 months) results. For the assessment of knee stability, anterior tibial translation was evaluated using the Lachman test and the KT-2000. Rotational stability was evaluated using pivot shift test. For clinical assessment, the Lysholm and International Knee Documentation Committee scores were used. Results The average anterior translation was 2.1±1.4 mm at the short-term follow-up and 2.8±1.8 mm at the mid-term follow-up. Stability and midterm clinical outcomes were not significantly improved compared to the short-term follow-up results. At the mid-term follow-up, anteroposterior (AP) instability assessed by the KT-2000 was slightly increased, but still acceptable. On the other clinical physical evaluation, there was no statistically significant difference. Conclusions The short-term and mid-term outcomes of ACL reconstruction using the two AM portal technique were not significantly different except for AP stability although the value was less than 3 mm at both follow-ups. Therefore, this operative technique could be considered a satisfactory alternative for ACL reconstruction. PMID:28231644

  10. L1/2 regularization based numerical method for effective reconstruction of bioluminescence tomography

    NASA Astrophysics Data System (ADS)

    Chen, Xueli; Yang, Defu; Zhang, Qitan; Liang, Jimin

    2014-05-01

    Even though bioluminescence tomography (BLT) exhibits significant potential and wide applications in macroscopic imaging of small animals in vivo, the inverse reconstruction is still a tough problem that has plagued researchers in a related area. The ill-posedness of inverse reconstruction arises from insufficient measurements and modeling errors, so that the inverse reconstruction cannot be solved directly. In this study, an l1/2 regularization based numerical method was developed for effective reconstruction of BLT. In the method, the inverse reconstruction of BLT was constrained into an l1/2 regularization problem, and then the weighted interior-point algorithm (WIPA) was applied to solve the problem through transforming it into obtaining the solution of a series of l1 regularizers. The feasibility and effectiveness of the proposed method were demonstrated with numerical simulations on a digital mouse. Stability verification experiments further illustrated the robustness of the proposed method for different levels of Gaussian noise.

  11. Comparison of reconstruction methods and quantitative accuracy in Siemens Inveon PET scanner

    NASA Astrophysics Data System (ADS)

    Ram Yu, A.; Kim, Jin Su; Kang, Joo Hyun; Moo Lim, Sang

    2015-04-01

    PET reconstruction is key to the quantification of PET data. To our knowledge, no comparative study of reconstruction methods has been performed to date. In this study, we compared reconstruction methods with various filters in terms of their spatial resolution, non-uniformities (NU), recovery coefficients (RCs), and spillover ratios (SORs). In addition, the linearity of reconstructed radioactivity between linearity of measured and true concentrations were also assessed. A Siemens Inveon PET scanner was used in this study. Spatial resolution was measured with NEMA standard by using a 1 mm3 sized 18F point source. Image quality was assessed in terms of NU, RC and SOR. To measure the effect of reconstruction algorithms and filters, data was reconstructed using FBP, 3D reprojection algorithm (3DRP), ordered subset expectation maximization 2D (OSEM 2D), and maximum a posteriori (MAP) with various filters or smoothing factors (β). To assess the linearity of reconstructed radioactivity, image quality phantom filled with 18F was used using FBP, OSEM and MAP (β =1.5 & 5 × 10-5). The highest achievable volumetric resolution was 2.31 mm3 and the highest RCs were obtained when OSEM 2D was used. SOR was 4.87% for air and 3.97% for water, obtained OSEM 2D reconstruction was used. The measured radioactivity of reconstruction image was proportional to the injected one for radioactivity below 16 MBq/ml when FBP or OSEM 2D reconstruction methods were used. By contrast, when the MAP reconstruction method was used, activity of reconstruction image increased proportionally, regardless of the amount of injected radioactivity. When OSEM 2D or FBP were used, the measured radioactivity concentration was reduced by 53% compared with true injected radioactivity for radioactivity <16 MBq/ml. The OSEM 2D reconstruction method provides the highest achievable volumetric resolution and highest RC among all the tested methods and yields a linear relation between the measured and true

  12. INFLUENCE OF ANTERIOR PAIN ON RESULTS FROM ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

    PubMed Central

    Vasconcelos, Wilson; Santos, Claudinei; Ferracini, Antonio Marcos; Dejour, David

    2015-01-01

    Objective: To examine the impact of residual pain on functional outcomes two years after arthroscopic anterior cruciate ligament (ACL) reconstruction and compare the types of graft used during the procedure (patellar vs. flexor). Method: A retrospective epidemiological study on 129 ACL reconstructions with a mean follow-up of 28 months was conducted. The presence, intensity and location of the anterior pain were investigated. Pain provocation tests were conducted, sensitivity was analyzed and functional scores were applied (IKDC, femoropatellar and SF-36), comparing the results with the type of graft used. Results: Anterior pain was present in 28% of patients with a mean intensity of 2.9 in 10. When pain was present, the functional scores decreased significantly. Abnormalities of knee sensitivity and gait occurred frequently with use of the patellar tendon, but there was no statistical difference regarding the presence of pain. Conclusion: The presence of anterior pain in ACL reconstructions, even if minimal, has a deleterious effect on the final outcome over the medium term. Because of the influence of graft harvesting on the presence of abnormalities of knee sensitivity and gait, choosing the graft should take into account the patient's professional and sports activities. PMID:27026984

  13. The Effects of Rehabilitation Protocol on Functional Recovery After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Dragicevic-Cvjetkovic, Dragana; Jandric, Slavica; Bijeljac, Sinisa; Palija, Stanislav; Manojlovic, Slavko; Talic, Goran

    2014-01-01

    ABSTRACT Introduction: The use of rehabilitation protocol which corresponds to surgical technique results in optimal postoperative outcome and functional recovery of patients to a pre-injury level of activity. The aim of this paper is to show the effects of the official rehabilitation protocol in our Institute on functional recovery of patients after anterior cruciate ligament (ACL) reconstruction. Patients and methods: In prospective study, we evaluated 70 males after ACL reconstruction using hamstring graft. Patients were divided into two groups according to the manner of conducting the postoperative rehabilitation. Group A consisted of 35 patients that followed postoperative rehabilitation according to the rehabilitation protocol. Group B also 35 patients, which did not undergo the rehabilitation protocol. We evaluated thigh muscle circumference and modified Tegner Lysholm Score, preoperatively and postoperatively after 1,3,6 and 12 months. In the statistical analysis, the Studentov T-test was used. Results: In the first postoperative month, the difference between groups in thigh muscle circumference is statistically significant (p<0,05). This difference between groups is statistically highly significant after 3, 6, and 12 months postoperative (p<0,01). Results of the modified Tegner Lysholm Score is statistically highly significant in 1, 3 and 6 postoperative months in patients from the experimental group (p<0,01). Conclusion: The positive effects of the rehabilitation protocol results in significant increase of the thigh muscle circumference and faster functional recovery of patients after ACL reconstruction. PMID:25568570

  14. Causes of Failure of Anterior Cruciate Ligament Reconstruction and Revision Surgical Strategies

    PubMed Central

    Di Benedetto, Paolo; Di Benedetto, Enrico; Fiocchi, Andrea; Beltrame, Alessandro; Causero, Araldo

    2016-01-01

    Purpose Long-term outcomes of anterior cruciate ligament (ACL) reconstruction are good or excellent; however, 0.7%–20% of patients suffer from recurrent instability due to graft failure. The purpose of this paper was to analyse failure aetiology and the possibilities of revision surgical strategies, with a description of our experience. We obtained optimal and good results in most of our patients. Materials and Methods We retrospectively reviewed 42 patients who underwent revision surgery (43 revisions) due to relapsing instability after ACL reconstruction between 2006 and 2015. We used allografts in 39 cases and autografts in 4 cases. Results The 85.7% of the patients obtained optimal results (normal knee; group A) and the 7.2% obtained good results (nearly normal knee; group B) according to the International Knee Documentation Committee score. The most frequent failure causes were traumatic events, non-anatomic tunnel placement, and lack of graft incorporation. Conclusions A correct revision surgery requires accurate patient evaluation and knee imaging. Preoperative planning starts with the identification of the cause of failure of the primary reconstruction. Then, the most suitable procedure should be determined for each case. It is also important to accurately inform the patient of all the complexity of an ACL revision surgery even if it is a procedure with high rates of excellent and good outcomes. PMID:27894180

  15. Evaluation of Infection after Anterior Cruciate Ligament Reconstruction during a Short Period

    PubMed Central

    Kim, Hee-June; Lee, Hyun-Joo; Lee, Jong-Chul; Min, Seung-Gi; Kyung, Hee-Soo

    2017-01-01

    Purpose We encountered 7 cases (7.1%) of infection (5 deep and 2 superficial) in 98 cases of anterior cruciate ligament (ACL) reconstruction using hamstring autografts in a 17-month period. The aim of this study was to analyze the causes of infection and to introduce our treatment strategy. Materials and Methods We investigated the shelf-life of the fixation implants, the order of surgery, previous knee surgery, infectious pathogen, treatment of infection, and results of treatment. Results There was no problem with the expiration date of the fixation implants. The order of surgery was either the last or second to the last of all those performed on the same day. One patient had undergone knee surgery 8 months previously. The treatment after infection included aggressive debridement in all cases. Revision ACL reconstruction with graft removal was performed in 1 case of persistent infection with methicillin-resistant Staphylococcus aureus. All cases had satisfactory clinical results without recurrence during a mean 24.9 months of follow-up. Conclusions We could not verify the exact cause of the high incidence of infection during the 17-month period. However, preventive measures are important to decrease the incidence of infection after ACL reconstruction. PMID:28231648

  16. New perspectives on ACL injury: On the role of repetitive sub-maximal knee loading in causing ACL fatigue failure.

    PubMed

    Wojtys, Edward M; Beaulieu, Mélanie L; Ashton-Miller, James A

    2016-12-01

    In this paper, we review a series of studies that we initiated to examine mechanisms of anterior cruciate ligament (ACL) injury in the hope that these injuries, and their sequelae, can be better prevented. First, using the earliest in vitro model of a simulated single-leg jump landing or pivot cut with realistic knee loading rates and trans-knee muscle forces, we identified the worst-case dynamic knee loading that causes the greatest peak ACL strain: Combined knee compression, flexion, and internal tibial rotation. We also identified morphologic factors that help explain individual susceptibility to ACL injury. Second, using the above knee loading, we introduced a possible paradigm shift in ACL research by demonstrating that the human ACL can fail by a sudden rupture in response to repeated sub-maximal knee loading. If that load is repeated often enough over a short time interval, the failure tended to occur proximally, as observed clinically. Third, we emphasize the value of a physical exam of the hip by demonstrating how limited internal axial rotation at the hip both increases the susceptibility to ACL injury in professional athletes, and also increases peak ACL strain during simulated pivot landings, thereby further increasing the risk of ACL fatigue failure. When training at-risk athletes, particularly females with their smaller ACL cross-sections, rationing the number and intensity of worst-case knee loading cycles, such that ligament degradation is within the ACL's ability to remodel, should decrease the risk for ACL rupture due to ligament fatigue failure.© 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2059-2068, 2016.

  17. [Intra-articular reinforcement of a partially torn anterior cruciate ligament (ACL) using newly developed UHMWPE biomaterial in combination with Hexalon ACL/PCL screws: ex-vivo mechanical testing of an animal knee model].

    PubMed

    Fedorová, P; Srnec, R; Pěnčík, J; Dvořák, M; Krbec, M; Nečas, A

    2015-01-01

    PURPOSE OF THE STUDY Recent trends in the experimental surgical management of a partial anterior cruciate ligament (ACL) rupture in animals show repair of an ACL lesion using novel biomaterials both for biomechanical reinforcement of a partially unstable knee and as suitable scaffolds for bone marrow stem cell therapy in a partial ACL tear. The study deals with mechanical testing of the newly developed ultra-high-molecular-weight polyethylene (UHMWPE) biomaterial anchored to bone with Hexalon biodegradable ACL/PCL screws, as a new possibility of intra-articular reinforcement of a partial ACL tear. MATERIAL AND METHODS Two groups of ex vivo pig knee models were prepared and tested as follows: the model of an ACL tear stabilised with UHMWPE biomaterial using a Hexalon ACL/PCL screw (group 1; n = 10) and the model of an ACL tear stabilised with the traditional, and in veterinary medicine used, extracapsular technique involving a monofilament nylon fibre, a clamp and a Securos bone anchor (group 2; n = 11). The models were loaded at a standing angle of 100° and the maximum load (N) and shift (mm) values were recorded. RESULTS In group 1 the average maximal peak force was 167.6 ± 21.7 N and the shift was on average 19.0 ± 4.0 mm. In all 10 specimens, the maximum load made the UHMWPE implant break close to its fixation to the femur but the construct/fixation never failed at the site where the material was anchored to the bone. In group 2, the average maximal peak force was 207.3 ± 49.2 N and the shift was on average 24.1 ± 9.5 mm. The Securos stabilisation failed by pullout of the anchor from the femoral bone in nine out of 11 cases; the monofilament fibre ruptured in two cases. CONCLUSIONS It can be concluded that a UHMWPE substitute used in ex-vivo pig knee models has mechanical properties comparable with clinically used extracapsular Securos stabilisation and, because of its potential to carry stem cells and bioactive substances, it can meet the requirements for

  18. Image reconstruction method IRBis for optical/infrared long-baseline interferometry

    NASA Astrophysics Data System (ADS)

    Hofmann, Karl-Heinz; Heininger, Matthias; Schertl, Dieter; Weigelt, Gerd; Millour, Florentin; Berio, Philippe

    2016-07-01

    IRBis is an image reconstruction method for optical/infrared long-baseline interferometry. IRBis can reconstruct images from (a) measured visibilities and closure phases, or from (b) measured complex visibilities (i.e. the Fourier phases and visibilities). The applied optimization routine ASA CG is based on conjugate gradients. The method allows the user to implement different regularizers, as for example, maximum entropy, smoothness, total variation, etc., and apply residual ratios as an additional metric for goodness-of-fit. In addition, IRBis allows the user to change the following reconstruction parameters: (a) FOV of the area to be reconstructed, (b) the size of the pixel-grid used, (c) size of a binary mask in image space allowing reconstructed intensities < 0 within the binary mask only, (d) the strength of the regularization, etc. The two main reconstruction parameters are the size of the binary mask in image space (c) and the strength of the regularization (d). Several values of these two parameters are tested within the algorithm. The quality of the different reconstructions obtained is roughly estimated by evaluation of the differences between the measured data and the reconstructed image (using the reduced χ2 values and the residual ratios). The best-quality reconstruction and a few reconstructions sorted according to their quality are provided to the user as resulting reconstructions. We describe the theory of IRBis and will present several applications to simulated interferometric data and data of real astronomical objects: (a) We have investigated image reconstruction experiments of MATISSE target candidates by computer simulations. We have modeled gaps in a disk of a young stellar object and have simulated interferometric data (squared visibilities and closure phases) with a signal-to-noise ratio as expected for MATISSE observations. We have performed image reconstruction experiments with this model for different flux levels of the target and

  19. A Novel Parallel Method for Speckle Masking Reconstruction Using the OpenMP

    NASA Astrophysics Data System (ADS)

    Li, Xuebao; Zheng, Yanfang

    2016-08-01

    High resolution reconstruction technology is developed to help enhance the spatial resolution of observational images for ground-based solar telescopes, such as speckle masking. Near real-time reconstruction performance is achieved on a high performance cluster using the Message Passing Interface (MPI). However, much time is spent in reconstructing solar subimages in such a speckle reconstruction. We design and implement a novel parallel method for speckle masking reconstruction of solar subimage on a shared memory machine using the OpenMP. Real tests are performed to verify the correctness of our codes. We present the details of several parallel reconstruction steps. The parallel implementation between various modules shows a great speed increase as compared to single thread serial implementation, and a speedup of about 2.5 is achieved in one subimage reconstruction. The timing result for reconstructing one subimage with 256×256 pixels shows a clear advantage with greater number of threads. This novel parallel method can be valuable in real-time reconstruction of solar images, especially after porting to a high performance cluster.

  20. Anatomical reconstruction of the anterior cruciate ligament: a logical approach.

    PubMed

    Gali, Julio Cesar

    2015-01-01

    We describe the surgical approach that we have used over the last years for anterior cruciate ligament (ACL) reconstruction, highlighting the importance of arthroscopic viewing through the anteromedial portal (AMP) and femoral tunnel drilling through an accessory anteromedial portal (AMP). The AMP allows direct view of the ACL femoral insertion site on the medial aspect of the lateral femoral condyle, does not require guides for anatomic femoral tunnel reaming, prevents an additional lateral incision in the distal third of the thigh (as would be unavoidable when the outside-in technique is used) and also can be used for double-bundle ACL reconstruction.

  1. Anatomical reconstruction of the anterior cruciate ligament: a logical approach

    PubMed Central

    Gali, Julio Cesar

    2015-01-01

    We describe the surgical approach that we have used over the last years for anterior cruciate ligament (ACL) reconstruction, highlighting the importance of arthroscopic viewing through the anteromedial portal (AMP) and femoral tunnel drilling through an accessory anteromedial portal (AMP). The AMP allows direct view of the ACL femoral insertion site on the medial aspect of the lateral femoral condyle, does not require guides for anatomic femoral tunnel reaming, prevents an additional lateral incision in the distal third of the thigh (as would be unavoidable when the outside-in technique is used) and also can be used for double-bundle ACL reconstruction. PMID:26417571

  2. Diffuse optical tomography reconstruction method using ultrasound images as prior for regularization matrix

    NASA Astrophysics Data System (ADS)

    Althobaiti, Murad; Vavadi, Hamed; Zhu, Quing

    2017-02-01

    Ultrasound-guided diffuse optical tomography (DOT) is a promising imaging technique that maps hemoglobin concentrations of breast lesions to assist ultrasound (US) for cancer diagnosis and treatment monitoring. The accurate recovery of breast lesion optical properties requires an effective image reconstruction method. We introduce a reconstruction approach in which US images are encoded as prior information for regularization of the inversion matrix. The framework of this approach is based on image reconstruction package "NIRFAST." We compare this approach to the US-guided dual-zone mesh reconstruction method, which is based on Born approximation and conjugate gradient optimization developed in our laboratory. Results were evaluated using phantoms and clinical data. This method improves classification of malignant and benign lesions by increasing malignant to benign lesion absorption contrast. The results also show improvements in reconstructed lesion shapes and the spatial distribution of absorption maps.

  3. The anatomy of the anterior cruciate ligament and its relevance to the technique of reconstruction.

    PubMed

    Śmigielski, R; Zdanowicz, U; Drwięga, M; Ciszek, B; Williams, A

    2016-08-01

    Anterior cruciate ligament (ACL) reconstruction is commonly performed and has been for many years. Despite this, the technical details related to ACL anatomy, such as tunnel placement, are still a topic for debate. In this paper, we introduce the flat ribbon concept of the anatomy of the ACL, and its relevance to clinical practice. Cite this article: Bone Joint J 2016;98-B:1020-6.

  4. An automated 3D reconstruction method of UAV images

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Wang, He; Liu, Xiaoyang; Li, Feng; Sun, Guangtong; Song, Ping

    2015-10-01

    In this paper a novel fully automated 3D reconstruction approach based on low-altitude unmanned aerial vehicle system (UAVs) images will be presented, which does not require previous camera calibration or any other external prior knowledge. Dense 3D point clouds are generated by integrating orderly feature extraction, image matching, structure from motion (SfM) and multi-view stereo (MVS) algorithms, overcoming many of the cost, time limitations of rigorous photogrammetry techniques. An image topology analysis strategy is introduced to speed up large scene reconstruction by taking advantage of the flight-control data acquired by UAV. Image topology map can significantly reduce the running time of feature matching by limiting the combination of images. A high-resolution digital surface model of the study area is produced base on UAV point clouds by constructing the triangular irregular network. Experimental results show that the proposed approach is robust and feasible for automatic 3D reconstruction of low-altitude UAV images, and has great potential for the acquisition of spatial information at large scales mapping, especially suitable for rapid response and precise modelling in disaster emergency.

  5. A new nonlinear reconstruction method based on total variation regularization of neutron penumbral imaging

    SciTech Connect

    Qian Weixin; Qi Shuangxi; Wang Wanli; Cheng Jinming; Liu Dongbing

    2011-09-15

    Neutron penumbral imaging is a significant diagnostic technique in laser-driven inertial confinement fusion experiment. It is very important to develop a new reconstruction method to improve the resolution of neutron penumbral imaging. A new nonlinear reconstruction method based on total variation (TV) regularization is proposed in this paper. A TV-norm is used as regularized term to construct a smoothing functional for penumbral image reconstruction in the new method, in this way, the problem of penumbral image reconstruction is transformed to the problem of a functional minimization. In addition, a fixed point iteration scheme is introduced to solve the problem of functional minimization. The numerical experimental results show that, compared to linear reconstruction method based on Wiener filter, the TV regularized nonlinear reconstruction method is beneficial to improve the quality of reconstructed image with better performance of noise smoothing and edge preserving. Meanwhile, it can also obtain the spatial resolution with 5 {mu}m which is higher than the Wiener method.

  6. Sparse Reconstruction Techniques in Magnetic Resonance Imaging: Methods, Applications, and Challenges to Clinical Adoption.

    PubMed

    Yang, Alice C; Kretzler, Madison; Sudarski, Sonja; Gulani, Vikas; Seiberlich, Nicole

    2016-06-01

    The family of sparse reconstruction techniques, including the recently introduced compressed sensing framework, has been extensively explored to reduce scan times in magnetic resonance imaging (MRI). While there are many different methods that fall under the general umbrella of sparse reconstructions, they all rely on the idea that a priori information about the sparsity of MR images can be used to reconstruct full images from undersampled data. This review describes the basic ideas behind sparse reconstruction techniques, how they could be applied to improve MRI, and the open challenges to their general adoption in a clinical setting. The fundamental principles underlying different classes of sparse reconstructions techniques are examined, and the requirements that each make on the undersampled data outlined. Applications that could potentially benefit from the accelerations that sparse reconstructions could provide are described, and clinical studies using sparse reconstructions reviewed. Lastly, technical and clinical challenges to widespread implementation of sparse reconstruction techniques, including optimization, reconstruction times, artifact appearance, and comparison with current gold standards, are discussed.

  7. Cost of Outpatient Arthroscopic Anterior Cruciate Ligament Reconstruction Among Commercially Insured Patients in the United States, 2005-2013

    PubMed Central

    Herzog, Mackenzie M.; Marshall, Stephen W.; Lund, Jennifer L.; Pate, Virginia; Spang, Jeffrey T.

    2017-01-01

    Background: Despite the significance of anterior cruciate ligament (ACL) injuries, these conditions have been under-researched from a population-level perspective. It is important to determine the economic effect of these injuries in order to document the public health burden in the United States. Purpose: To describe the cost of outpatient arthroscopic ACL reconstruction and health care utilization among commercially insured beneficiaries in the United States. Study Design: Economic and decision analysis; Level of evidence, 3. Methods: The study used the Truven Health Analytics MarketScan Commercial Claims and Encounters database, an administrative claims database that contains a large sample (approximately 148 million) of privately insured individuals aged <65 years and enrolled in employer-sponsored plans. All claims with Current Procedural Terminology (CPT) code 29888 (arthroscopically aided ACL reconstruction or augmentation) from 2005 to 2013 were included. “Immediate procedure” cost was computed assuming a 3-day window of care centered on date of surgery. “Total health care utilization” cost was computed using a 9-month window of care (3 months preoperative and 6 months postoperative). Results: There were 229,446 outpatient arthroscopic ACL reconstructions performed over the 9-year study period. Median immediate procedure cost was $9399.49. Median total health care utilization cost was $13,403.38. Patients who underwent concomitant collateral ligament (medial [MCL], lateral [LCL]) repair or reconstruction had the highest costs for both immediate procedure ($12,473.24) and health care utilization ($17,006.34). For patients who had more than 1 reconstruction captured in the database, total health care utilization costs were higher for the second procedure than the first procedure ($16,238.43 vs $15,000.36), despite the fact that immediate procedure costs were lower for second procedures ($8685.73 vs $9445.26). Conclusion: These results provide a

  8. Landing Mechanics During Side Hopping and Crossover Hopping Maneuvers in Noninjured Women and Women With Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Ortiz, Alexis; Olson, Sharon; Trudelle-Jackson, Elaine; Rosario, Martin; Venegas, Heidi L.

    2011-01-01

    Objective To compare, landing mechanics and electromyographic activity of the lower extremities during side hopping and crossover hopping maneuvers, in noninjured women and women with anterior cruciate ligament (ACL) reconstruction. Design A case-control study. Setting A 3-dimensional motion analysis laboratory. Participants Twenty-eight young women (range, 21–35 years) (15 control subjects and 13 subjects with ACL reconstruction). Patients and Methods All participants performed a side-to-side hopping task that consisted of hopping single-legged 10 times consecutively from side to side across 2 lines marked 30 cm apart on 2 individual force plates. The task was designated as a side hopping when the hop was to the opposite side of the stance leg and as crossover hopping when the hop was toward the side of the stance leg. Main Outcome Measurements Peak hip-/knee-joint angles; peak knee extension/abduction joint moments; electromyographic studies of the gluteus maximus, gluteus medius, rectus femoris, and hamstring muscles; and quadriceps/hamstring co-contraction ratio were compared between the groups by means of 2 × 2 multivariate analysis of variance tests (group × maneuver). Results Noninjured women and women with ACL reconstruction exhibited similar hip-and knee-joint angles during both types of hopping. Hip-joint angles were greater during the crossover hopping in both groups, and knee-joint angles did not differ between the groups or hops. Knee-joint moments demonstrated a significant group × maneuver interaction. Greater knee extension and valgus moments were noted in the control group during crossover hopping, and greater knee abduction moments were noted in the ACL group during side hopping. Electromyographic data revealed no statistically significantly differences between the groups. Conclusions Women with ACL reconstruction exhibited the restoration of functional biomechanical movements such as hip-/knee-joint angles and lower extremity neuromuscular

  9. Improvement of the background optical property reconstruction of the two-layered slab sample based on a region-stepwise-reconstruction method

    NASA Astrophysics Data System (ADS)

    Liu, Ming; Qin, Zhuanping; Jia, Mengyu; Zhao, Huijuan; Gao, Feng

    2015-03-01

    Two-layered slab is a rational simplified sample to the near-infrared functional brain imaging using diffuse optical tomography (DOT).The quality of reconstructed images is substantially affected by the accuracy of the background optical properties. In this paper, region step wise reconstruction method is proposed for reconstructing the background optical properties of the two-layered slab sample with the known geometric information based on continuous wave (CW) DOT. The optical properties of the top and bottom layers are respectively reconstructed utilizing the different source-detector-separation groups according to the depth of maximum brain sensitivity of the source-detector-separation. We demonstrate the feasibility of the proposed method and investigate the application range of the source-detector-separation groups by the numerical simulations. The numerical simulation results indicate the proposed method can effectively reconstruct the background optical properties of two-layered slab sample. The relative reconstruction errors are less than 10% when the thickness of the top layer is approximate 10mm. The reconstruction of target caused by brain activation is investigated with the reconstructed optical properties as well. The quantitativeness ratio of the ROI is about 80% which is higher than that of the conventional method. The spatial resolution of the reconstructions (R) with two targets is investigated, and it demonstrates R with the proposed method is better than that with the conventional method as well.

  10. The New Method of Tsunami Source Reconstruction With r-Solution Inversion Method

    NASA Astrophysics Data System (ADS)

    Voronina, T. A.; Romanenko, A. A.

    2016-12-01

    Application of the r-solution method to reconstructing the initial tsunami waveform is discussed. This methodology is based on the inversion of remote measurements of water-level data. The wave propagation is considered within the scope of a linear shallow-water theory. The ill-posed inverse problem in question is regularized by means of a least square inversion using the truncated Singular Value Decomposition method. As a result of the numerical process, an r-solution is obtained. The method proposed allows one to control the instability of a numerical solution and to obtain an acceptable result in spite of ill posedness of the problem. Implementation of this methodology to reconstructing of the initial waveform to 2013 Solomon Islands tsunami validates the theoretical conclusion for synthetic data and a model tsunami source: the inversion result strongly depends on data noisiness, the azimuthal and temporal coverage of recording stations with respect to the source area. Furthermore, it is possible to make a preliminary selection of the most informative set of the available recording stations used in the inversion process.

  11. Clinical Results of Technique for Double Bundle Anterior Cruciate Ligament Reconstruction Using Hybrid Femoral Fixation and Retroscrew

    PubMed Central

    Kim, Doo-Sup; Yi, Chang-Ho; Chung, Hoi-Jung

    2011-01-01

    Background Anatomic anterior cruciate ligament (ACL) reconstruction has been presented as a means to more accurately restore the native anatomy of this ligament. This article describes a new method that uses a double bundle to perform ACL reconstruction and to evaluate the clinical outcome. Methods Grafts are tibialis anterior tendon allograft for anteromedial bundle (AMB) and hamstring tendon autograft without detachment of the tibial insertion for posterolateral bundle (PLB). This technique creates 2 tunnels in both the femur and tibia. Femoral fixation was done by hybrid fixation using Endobutton and Rigidfix for AMB and by biointerference screw for PLB. Tibial fixations are done by Retroscrew for AMB and by native insertion of hamstring tendon for PLB. Both bundles are independently and differently tensioned. We performed ACL reconstruction in 63 patients using our new technique. Among them, 47 participated in this study. The patients were followed up with clinical examination, Lysholm scales and International Knee Documentation Committee (IKDC) scoring system and radiological examination with a minimum 12 month follow-up duration. Results Significant improvement was seen on Lachman test and pivot-shift test between preoperative and last follow-up. Only one of participants had flexion contracture about 5 degrees at last follow-up. In anterior drawer test by KT-1000, authors found improvement from average 8.3 mm (range, 4 to 18 mm) preoperatively to average 1.4 mm (range, 0 to 6 mm) at last follow-up. Average Lysholm score of all patients was 72.7 ± 8.8 (range, 54 to 79) preoperatively and significant improvement was seen, score was 92.2 ± 5.3 (range, 74 to 97; p < 0.05) at last follow-up. Also IKDC score was normal in 35 cases, near normal in 11 cases, abnormal in 1 case at last follow-up. Conclusions Our new double bundle ACL reconstruction technique used hybrid fixation and Retroscrew had favorable outcomes. PMID:22162791

  12. Simultaneous denoising and reconstruction of 5-D seismic data via damped rank-reduction method

    NASA Astrophysics Data System (ADS)

    Chen, Yangkang; Zhang, Dong; Jin, Zhaoyu; Chen, Xiaohong; Zu, Shaohuan; Huang, Weilin; Gan, Shuwei

    2016-09-01

    The Cadzow rank-reduction method can be effectively utilized in simultaneously denoising and reconstructing 5-D seismic data that depend on four spatial dimensions. The classic version of Cadzow rank-reduction method arranges the 4-D spatial data into a level-four block Hankel/Toeplitz matrix and then applies truncated singular value decomposition (TSVD) for rank reduction. When the observed data are extremely noisy, which is often the feature of real seismic data, traditional TSVD cannot be adequate for attenuating the noise and reconstructing the signals. The reconstructed data tend to contain a significant amount of residual noise using the traditional TSVD method, which can be explained by the fact that the reconstructed data space is a mixture of both signal subspace and noise subspace. In order to better decompose the block Hankel matrix into signal and noise components, we introduced a damping operator into the traditional TSVD formula, which we call the damped rank-reduction method. The damped rank-reduction method can obtain a perfect reconstruction performance even when the observed data have extremely low signal-to-noise ratio. The feasibility of the improved 5-D seismic data reconstruction method was validated via both 5-D synthetic and field data examples. We presented comprehensive analysis of the data examples and obtained valuable experience and guidelines in better utilizing the proposed method in practice. Since the proposed method is convenient to implement and can achieve immediate improvement, we suggest its wide application in the industry.

  13. A Parallel Reconstructed Discontinuous Galerkin Method for the Compressible Flows on Aritrary Grids

    SciTech Connect

    Hong Luo; Amjad Ali; Robert Nourgaliev; Vincent A. Mousseau

    2010-01-01

    A reconstruction-based discontinuous Galerkin method is presented for the solution of the compressible Navier-Stokes equations on arbitrary grids. In this method, an in-cell reconstruction is used to obtain a higher-order polynomial representation of the underlying discontinuous Galerkin polynomial solution and an inter-cell reconstruction is used to obtain a continuous polynomial solution on the union of two neighboring, interface-sharing cells. The in-cell reconstruction is designed to enhance the accuracy of the discontinuous Galerkin method by increasing the order of the underlying polynomial solution. The inter-cell reconstruction is devised to remove an interface discontinuity of the solution and its derivatives and thus to provide a simple, accurate, consistent, and robust approximation to the viscous and heat fluxes in the Navier-Stokes equations. A parallel strategy is also devised for the resulting reconstruction discontinuous Galerkin method, which is based on domain partitioning and Single Program Multiple Data (SPMD) parallel programming model. The RDG method is used to compute a variety of compressible flow problems on arbitrary meshes to demonstrate its accuracy, efficiency, robustness, and versatility. The numerical results demonstrate that this RDG method is third-order accurate at a cost slightly higher than its underlying second-order DG method, at the same time providing a better performance than the third order DG method, in terms of both computing costs and storage requirements.

  14. [Novel method of noise power spectrum measurement for computed tomography images with adaptive iterative reconstruction method].

    PubMed

    Nishimaru, Eiji; Ichikawa, Katsuhiro; Hara, Takanori; Terakawa, Shoichi; Yokomachi, Kazushi; Fujioka, Chikako; Kiguchi, Masao; Ishifuro, Minoru

    2012-01-01

    Adaptive iterative reconstruction techniques (IRs) can decrease image noise in computed tomography (CT) and are expected to contribute to reduction of the radiation dose. To evaluate the performance of IRs, the conventional two-dimensional (2D) noise power spectrum (NPS) is widely used. However, when an IR provides an NPS value drop at all spatial frequency (which is similar to NPS changes by dose increase), the conventional method cannot evaluate the correct noise property because the conventional method does not correspond to the volume data natures of CT images. The purpose of our study was to develop a new method for NPS measurements that can be adapted to IRs. Our method utilized thick multi-planar reconstruction (MPR) images. The thick images are generally made by averaging CT volume data in a direction perpendicular to a MPR plane (e.g. z-direction for axial MPR plane). By using this averaging technique as a cutter for 3D-NPS, we can obtain adequate 2D-extracted NPS (eNPS) from 3D NPS. We applied this method to IR images generated with adaptive iterative dose reduction 3D (AIDR-3D, Toshiba) to investigate the validity of our method. A water phantom with 24 cm-diameters was scanned at 120 kV and 200 mAs with a 320-row CT (Acquilion One, Toshiba). From the results of study, the adequate thickness of MPR images for eNPS was more than 25.0 mm. Our new NPS measurement method utilizing thick MPR images was accurate and effective for evaluating noise reduction effects of IRs.

  15. A Wearable Neuromuscular Device Reduces ACL Injury Risk in Female Soccer Athletes

    PubMed Central

    Decker, Michael John; Shaw, Matthew; Maddan, Casey; Campbell, Julie; Davidson, Bradley

    2016-01-01

    Objectives: Female soccer athletes have a three-fold greater risk of sustaining an ACL injury compared with their male counterparts yet only 1 in 5 teams engage in ACL risk reduction programs due to several participation barriers. The purpose of this study was to determine the effects of a wearable neuromuscular (WNM) device on postural control, performance and ACL injury risk in female soccer athletes. Methods: Seventy-nine elite youth and collegiate female soccer athletes (age range: 12-25 y) trained with a WNM device that applied bi-lateral, topical pressure to the medial quadriceps and hamstrings muscles (Topical Gear, Austin, TX). The athletes performed 7-9 weeks of pre-season training with the WNM device consisting of strength and conditioning exercises and on-field team practices (46-64 total hours of exposure). Postural control was measured in 15 athletes with and without the WNM device before and after the training program; and performance was measured in 25 athletes without the WNM device before and after the training program. Postural control was determined from a single-leg landing on a force plate from a horizontal distance normalized to leg length. The athletes were instructed to gain their balance as fast as possible upon landing and remain balanced for 5 seconds. The peak ground reaction forces (GRF) and the medial-lateral, anterior-posterior and net center of pressure (COP) velocities and displacement ranges were calculated during 2 seconds of single-leg stance. Performance measures including speed, power and endurance were measured from the 40 yard dash, vertical jump for height and the Beep test, respectively. A two-way repeated measures ANOVA and post-hoc comparisons were used to compare the postural variables; and t-tests were used to compare the performance tests (p=.05). ACL injury rates, the absolute risk reduction (ARR) and the number needed to treat (NNT) to prevent one ACL injury were calculated between the WNM intervention group and 11

  16. Linearized image reconstruction method for ultrasound modulated electrical impedance tomography based on power density distribution

    NASA Astrophysics Data System (ADS)

    Song, Xizi; Xu, Yanbin; Dong, Feng

    2017-04-01

    Electrical resistance tomography (ERT) is a promising measurement technique with important industrial and clinical applications. However, with limited effective measurements, it suffers from poor spatial resolution due to the ill-posedness of the inverse problem. Recently, there has been an increasing research interest in hybrid imaging techniques, utilizing couplings of physical modalities, because these techniques obtain much more effective measurement information and promise high resolution. Ultrasound modulated electrical impedance tomography (UMEIT) is one of the newly developed hybrid imaging techniques, which combines electric and acoustic modalities. A linearized image reconstruction method based on power density is proposed for UMEIT. The interior data, power density distribution, is adopted to reconstruct the conductivity distribution with the proposed image reconstruction method. At the same time, relating the power density change to the change in conductivity, the Jacobian matrix is employed to make the nonlinear problem into a linear one. The analytic formulation of this Jacobian matrix is derived and its effectiveness is also verified. In addition, different excitation patterns are tested and analyzed, and opposite excitation provides the best performance with the proposed method. Also, multiple power density distributions are combined to implement image reconstruction. Finally, image reconstruction is implemented with the linear back-projection (LBP) algorithm. Compared with ERT, with the proposed image reconstruction method, UMEIT can produce reconstructed images with higher quality and better quantitative evaluation results.

  17. Iterative reconstruction methods in atmospheric tomography: FEWHA, Kaczmarz and Gradient-based algorithm

    NASA Astrophysics Data System (ADS)

    Ramlau, R.; Saxenhuber, D.; Yudytskiy, M.

    2014-07-01

    The problem of atmospheric tomography arises in ground-based telescope imaging with adaptive optics (AO), where one aims to compensate in real-time for the rapidly changing optical distortions in the atmosphere. Many of these systems depend on a sufficient reconstruction of the turbulence profiles in order to obtain a good correction. Due to steadily growing telescope sizes, there is a strong increase in the computational load for atmospheric reconstruction with current methods, first and foremost the MVM. In this paper we present and compare three novel iterative reconstruction methods. The first iterative approach is the Finite Element- Wavelet Hybrid Algorithm (FEWHA), which combines wavelet-based techniques and conjugate gradient schemes to efficiently and accurately tackle the problem of atmospheric reconstruction. The method is extremely fast, highly flexible and yields superior quality. Another novel iterative reconstruction algorithm is the three step approach which decouples the problem in the reconstruction of the incoming wavefronts, the reconstruction of the turbulent layers (atmospheric tomography) and the computation of the best mirror correction (fitting step). For the atmospheric tomography problem within the three step approach, the Kaczmarz algorithm and the Gradient-based method have been developed. We present a detailed comparison of our reconstructors both in terms of quality and speed performance in the context of a Multi-Object Adaptive Optics (MOAO) system for the E-ELT setting on OCTOPUS, the ESO end-to-end simulation tool.

  18. A general few-projection method for tomographic reconstruction of samples consisting of several distinct materials

    SciTech Connect

    Myers, Glenn R.; Thomas, C. David L.; Clement, John G.; Paganin, David M.; Gureyev, Timur E.

    2010-01-11

    We present a method for tomographic reconstruction of objects containing several distinct materials, which is capable of accurately reconstructing a sample from vastly fewer angular projections than required by conventional algorithms. The algorithm is more general than many previous discrete tomography methods, as: (i) a priori knowledge of the exact number of materials is not required; (ii) the linear attenuation coefficient of each constituent material may assume a small range of a priori unknown values. We present reconstructions from an experimental x-ray computed tomography scan of cortical bone acquired at the SPring-8 synchrotron.

  19. A general few-projection method for tomographic reconstruction of samples consisting of several distinct materials

    NASA Astrophysics Data System (ADS)

    Myers, Glenn R.; Thomas, C. David L.; Paganin, David M.; Gureyev, Timur E.; Clement, John G.

    2010-01-01

    We present a method for tomographic reconstruction of objects containing several distinct materials, which is capable of accurately reconstructing a sample from vastly fewer angular projections than required by conventional algorithms. The algorithm is more general than many previous discrete tomography methods, as: (i) a priori knowledge of the exact number of materials is not required; (ii) the linear attenuation coefficient of each constituent material may assume a small range of a priori unknown values. We present reconstructions from an experimental x-ray computed tomography scan of cortical bone acquired at the SPring-8 synchrotron.

  20. Image Reconstruction in SNR Units: A General Method for SNR Measurement

    PubMed Central

    Kellman, Peter; McVeigh, Elliot R.

    2007-01-01

    The method for phased array image reconstruction of uniform noise images may be used in conjunction with proper image scaling as a means of reconstructing images directly in SNR units. This facilitates accurate and precise SNR measurement on a per pixel basis. This method is applicable to root-sum-of-squares magnitude combining, B1-weighted combining, and parallel imaging such as SENSE. A procedure for image reconstruction and scaling is presented, and the method for SNR measurement is validated with phantom data. Alternative methods that rely on noise only regions are not appropriate for parallel imaging where the noise level is highly variable across the field-of-view. The purpose of this article is to provide a nuts and bolts procedure for calculating scale factors used for reconstructing images directly in SNR units. The procedure includes scaling for noise equivalent bandwidth of digital receivers, FFTs and associated window functions (raw data filters), and array combining. PMID:16261576

  1. Reproducibility of the Structural Connectome Reconstruction across Diffusion Methods.

    PubMed

    Prčkovska, Vesna; Rodrigues, Paulo; Puigdellivol Sanchez, Ana; Ramos, Marc; Andorra, Magi; Martinez-Heras, Eloy; Falcon, Carles; Prats-Galino, Albert; Villoslada, Pablo

    2016-01-01

    Analysis of the structural connectomes can lead to powerful insights about the brain's organization and damage. However, the accuracy and reproducibility of constructing the structural connectome done with different acquisition and reconstruction techniques is not well defined. In this work, we evaluated the reproducibility of the structural connectome techniques by performing test-retest (same day) and longitudinal studies (after 1 month) as well as analyzing graph-based measures on the data acquired from 22 healthy volunteers (6 subjects were used for the longitudinal study). We compared connectivity matrices and tract reconstructions obtained with the most typical acquisition schemes used in clinical application: diffusion tensor imaging (DTI), high angular resolution diffusion imaging (HARDI), and diffusion spectrum imaging (DSI). We observed that all techniques showed high reproducibility in the test-retest analysis (correlation >.9). However, HARDI was the only technique with low variability (2%) in the longitudinal assessment (1-month interval). The intraclass coefficient analysis showed the highest reproducibility for the DTI connectome, however, with more sparse connections than HARDI and DSI. Qualitative (neuroanatomical) assessment of selected tracts confirmed the quantitative results showing that HARDI managed to detect most of the analyzed fiber groups and fanning fibers. In conclusion, we found that HARDI acquisition showed the most balanced trade-off between high reproducibility of the connectome, higher rate of path detection and of fanning fibers, and intermediate acquisition times (10-15 minutes), although at the cost of higher appearance of aberrant fibers.

  2. Validation of plasma shape reconstruction by Cauchy condition surface method in KSTAR

    SciTech Connect

    Miyata, Y.; Suzuki, T.; Ide, S.; Hahn, S. H.; Chung, J.; Bak, J. G.; Ko, W. H.

    2014-03-15

    Cauchy Condition Surface (CCS) method is a numerical approach to reconstruct the plasma boundary and calculate the quantities related to plasma shape using the magnetic diagnostics in real time. It has been applied to the KSTAR plasma in order to establish the plasma shape reconstruction with the high elongation of plasma shape and the large effect of eddy currents flowing in the tokamak structures for the first time. For applying the CCS calculation to the KSTAR plasma, the effects by the eddy currents and the ferromagnetic materials on the plasma shape reconstruction are studied. The CCS calculation includes the effect of eddy currents and excludes the magnetic diagnostics, which is expected to be influenced largely by ferromagnetic materials. Calculations have been performed to validate the plasma shape reconstruction in 2012 KSTAR experimental campaign. Comparison between the CCS calculation and non-magnetic measurements revealed that the CCS calculation can reconstruct the accurate plasma shape even with a small I{sub P}.

  3. A systematic investigation of reflectance diffuse optical tomography using nonlinear reconstruction methods and continuous wave measurements

    PubMed Central

    Yuan, Zhen; Zhang, Jiang; Wang, Xiaodong; Li, Changqing

    2014-01-01

    We conducted a systematic investigation of the reflectance diffuse optical tomography using continuous wave (CW) measurements and nonlinear reconstruction algorithms. We illustrated and suggested how to fine-tune the nonlinear reconstruction methods in order to optimize target localization with depth-adaptive regularizations, reduce boundary noises in the reconstructed images using a logarithm based objective function, improve reconstruction quantification using transport models, and resolve crosstalk problems between absorption and scattering contrasts with the CW reflectance measurements. The upgraded nonlinear reconstruction algorithms were evaluated with a series of numerical and experimental tests, which show the potentials of the proposed approaches for imaging both absorption and scattering contrasts in the deep targets with enhanced image quality. PMID:25401014

  4. MR-guided dynamic PET reconstruction with the kernel method and spectral temporal basis functions

    NASA Astrophysics Data System (ADS)

    Novosad, Philip; Reader, Andrew J.

    2016-06-01

    Recent advances in dynamic positron emission tomography (PET) reconstruction have demonstrated that it is possible to achieve markedly improved end-point kinetic parameter maps by incorporating a temporal model of the radiotracer directly into the reconstruction algorithm. In this work we have developed a highly constrained, fully dynamic PET reconstruction algorithm incorporating both spectral analysis temporal basis functions and spatial basis functions derived from the kernel method applied to a co-registered T1-weighted magnetic resonance (MR) image. The dynamic PET image is modelled as a linear combination of spatial and temporal basis functions, and a maximum likelihood estimate for the coefficients can be found using the expectation-maximization (EM) algorithm. Following reconstruction, kinetic fitting using any temporal model of interest can be applied. Based on a BrainWeb T1-weighted MR phantom, we performed a realistic dynamic [18F]FDG simulation study with two noise levels, and investigated the quantitative performance of the proposed reconstruction algorithm, comparing it with reconstructions incorporating either spectral analysis temporal basis functions alone or kernel spatial basis functions alone, as well as with conventional frame-independent reconstruction. Compared to the other reconstruction algorithms, the proposed algorithm achieved superior performance, offering a decrease in spatially averaged pixel-level root-mean-square-error on post-reconstruction kinetic parametric maps in the grey/white matter, as well as in the tumours when they were present on the co-registered MR image. When the tumours were not visible in the MR image, reconstruction with the proposed algorithm performed similarly to reconstruction with spectral temporal basis functions and was superior to both conventional frame-independent reconstruction and frame-independent reconstruction with kernel spatial basis functions. Furthermore, we demonstrate that a joint spectral

  5. MR-guided dynamic PET reconstruction with the kernel method and spectral temporal basis functions.

    PubMed

    Novosad, Philip; Reader, Andrew J

    2016-06-21

    Recent advances in dynamic positron emission tomography (PET) reconstruction have demonstrated that it is possible to achieve markedly improved end-point kinetic parameter maps by incorporating a temporal model of the radiotracer directly into the reconstruction algorithm. In this work we have developed a highly constrained, fully dynamic PET reconstruction algorithm incorporating both spectral analysis temporal basis functions and spatial basis functions derived from the kernel method applied to a co-registered T1-weighted magnetic resonance (MR) image. The dynamic PET image is modelled as a linear combination of spatial and temporal basis functions, and a maximum likelihood estimate for the coefficients can be found using the expectation-maximization (EM) algorithm. Following reconstruction, kinetic fitting using any temporal model of interest can be applied. Based on a BrainWeb T1-weighted MR phantom, we performed a realistic dynamic [(18)F]FDG simulation study with two noise levels, and investigated the quantitative performance of the proposed reconstruction algorithm, comparing it with reconstructions incorporating either spectral analysis temporal basis functions alone or kernel spatial basis functions alone, as well as with conventional frame-independent reconstruction. Compared to the other reconstruction algorithms, the proposed algorithm achieved superior performance, offering a decrease in spatially averaged pixel-level root-mean-square-error on post-reconstruction kinetic parametric maps in the grey/white matter, as well as in the tumours when they were present on the co-registered MR image. When the tumours were not visible in the MR image, reconstruction with the proposed algorithm performed similarly to reconstruction with spectral temporal basis functions and was superior to both conventional frame-independent reconstruction and frame-independent reconstruction with kernel spatial basis functions. Furthermore, we demonstrate that a joint spectral

  6. Direct reconstruction of pharmacokinetic parameters in dynamic fluorescence molecular tomography by the augmented Lagrangian method

    NASA Astrophysics Data System (ADS)

    Zhu, Dianwen; Zhang, Wei; Zhao, Yue; Li, Changqing

    2016-03-01

    Dynamic fluorescence molecular tomography (FMT) has the potential to quantify physiological or biochemical information, known as pharmacokinetic parameters, which are important for cancer detection, drug development and delivery etc. To image those parameters, there are indirect methods, which are easier to implement but tend to provide images with low signal-to-noise ratio, and direct methods, which model all the measurement noises together and are statistically more efficient. The direct reconstruction methods in dynamic FMT have attracted a lot of attention recently. However, the coupling of tomographic image reconstruction and nonlinearity of kinetic parameter estimation due to the compartment modeling has imposed a huge computational burden to the direct reconstruction of the kinetic parameters. In this paper, we propose to take advantage of both the direct and indirect reconstruction ideas through a variable splitting strategy under the augmented Lagrangian framework. Each iteration of the direct reconstruction is split into two steps: the dynamic FMT image reconstruction and the node-wise nonlinear least squares fitting of the pharmacokinetic parameter images. Through numerical simulation studies, we have found that the proposed algorithm can achieve good reconstruction results within a small amount of time. This will be the first step for a combined dynamic PET and FMT imaging in the future.

  7. Time-frequency manifold sparse reconstruction: A novel method for bearing fault feature extraction

    NASA Astrophysics Data System (ADS)

    Ding, Xiaoxi; He, Qingbo

    2016-12-01

    In this paper, a novel transient signal reconstruction method, called time-frequency manifold (TFM) sparse reconstruction, is proposed for bearing fault feature extraction. This method introduces image sparse reconstruction into the TFM analysis framework. According to the excellent denoising performance of TFM, a more effective time-frequency (TF) dictionary can be learned from the TFM signature by image sparse decomposition based on orthogonal matching pursuit (OMP). Then, the TF distribution (TFD) of the raw signal in a reconstructed phase space would be re-expressed with the sum of learned TF atoms multiplied by corresponding coefficients. Finally, one-dimensional signal can be achieved again by the inverse process of TF analysis (TFA). Meanwhile, the amplitude information of the raw signal would be well reconstructed. The proposed technique combines the merits of the TFM in denoising and the atomic decomposition in image sparse reconstruction. Moreover, the combination makes it possible to express the nonlinear signal processing results explicitly in theory. The effectiveness of the proposed TFM sparse reconstruction method is verified by experimental analysis for bearing fault feature extraction.

  8. Stable-phase method for hierarchical annealing in the reconstruction of porous media images.

    PubMed

    Chen, Dongdong; Teng, Qizhi; He, Xiaohai; Xu, Zhi; Li, Zhengji

    2014-01-01

    In this paper, we introduce a stable-phase approach for hierarchical annealing which addresses the very large computational costs associated with simulated annealing for the reconstruction of large-scale binary porous media images. Our presented method, which uses the two-point correlation function as the morphological descriptor, involves the reconstruction of three-phase and two-phase structures. We consider reconstructing the three-phase structures based on standard annealing and the two-phase structures based on standard and hierarchical annealings. From the result of the two-dimensional (2D) reconstruction, we find that the 2D generation does not fully capture the morphological information of the original image, even though the two-point correlation function of the reconstruction is in excellent agreement with that of the reference image. For the reconstructed three-dimensional (3D) microstructure, we calculate its permeability and compare it to that of the reference 3D microstructure. The result indicates that the reconstructed structure has a lower degree of connectedness than that of the actual sandstone. We also compare the computation time of our presented method to that of the standard annealing, which shows that our presented method of orders of magnitude improves the convergence rate. That is because only a small part of the pixels in the overall hierarchy need to be considered for sampling by the annealer.

  9. Reconstruction of vibroacoustic responses of a highly nonspherical structure using Helmholtz equation least-squares method.

    PubMed

    Lu, Huancai; Wu, Sean F

    2009-03-01

    The vibroacoustic responses of a highly nonspherical vibrating object are reconstructed using Helmholtz equation least-squares (HELS) method. The objectives of this study are to examine the accuracy of reconstruction and the impacts of various parameters involved in reconstruction using HELS. The test object is a simply supported and baffled thin plate. The reason for selecting this object is that it represents a class of structures that cannot be exactly described by the spherical Hankel functions and spherical harmonics, which are taken as the basis functions in the HELS formulation, yet the analytic solutions to vibroacoustic responses of a baffled plate are readily available so the accuracy of reconstruction can be checked accurately. The input field acoustic pressures for reconstruction are generated by the Rayleigh integral. The reconstructed normal surface velocities are validated against the benchmark values, and the out-of-plane vibration patterns at several natural frequencies are compared with the natural modes of a simply supported plate. The impacts of various parameters such as number of measurement points, measurement distance, location of the origin of the coordinate system, microphone spacing, and ratio of measurement aperture size to the area of source surface of reconstruction on the resultant accuracy of reconstruction are examined.

  10. Climate space, bioclimatic envelopes and coexistence methods for the reconstruction of past climates: a method using Australian beetles and significance for Quaternary reconstruction

    NASA Astrophysics Data System (ADS)

    Porch, Nick

    2010-03-01

    If Quaternary palaeoclimatic reconstructions are to be adequately contextualised, it is vital that the nature of modern datasets and the limitations this places on interpreting Quaternary climates are made explicit - such issues are too infrequently considered. This paper describes a coexistence method for the reconstruction of past temperature and precipitation parameters in Australia, using fossil beetles. It presents the context for Quaternary palaeoclimatic reconstruction in terms of climate space, bioclimatic envelope data derived from modern beetle distributions, and the palaeoclimatic limitations of bioclimatic envelope-based reconstructions. Tests in modern climate space, using bioclimatic envelope data for 734 beetle taxa and 54 site-based assemblages from across the continent, indicate that modern seasonal, especially summer, temperatures and precipitation are accurately and, in the case of temperature, precisely reconstructed. The limitations of modern climate space, especially in terms of the limited seasonal variation in thermal regimes and subsequent lack of cold winters in the Australian region, renders winter predictions potentially unreliable when applied to the Quaternary record.

  11. Development of threedimensional optical correction method for reconstruction of flow field in droplet

    NASA Astrophysics Data System (ADS)

    Ko, Han Seo; Gim, Yeonghyeon; Kang, Seung-Hwan

    2015-11-01

    A three-dimensional optical correction method was developed to reconstruct droplet-based flow fields. For a numerical simulation, synthetic phantoms were reconstructed by a simultaneous multiplicative algebraic reconstruction technique using three projection images which were positioned at an offset angle of 45°. If the synthetic phantom in a conical object with refraction index which differs from atmosphere, the image can be distorted because a light is refracted on the surface of the conical object. Thus, the direction of the projection ray was replaced by the refracted ray which occurred on the surface of the conical object. In order to prove the method considering the distorted effect, reconstruction results of the developed method were compared with the original phantom. As a result, the reconstruction result of the method showed smaller error than that without the method. The method was applied for a Taylor cone which was caused by high voltage between a droplet and a substrate to reconstruct the three-dimensional flow fields for analysis of the characteristics of the droplet. This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Korean government (MEST) (No. 2013R1A2A2A01068653).

  12. Apparatus And Method For Reconstructing Data Using Cross-Parity Stripes On Storage Media

    DOEpatents

    Hughes, James Prescott

    2003-06-17

    An apparatus and method for reconstructing missing data using cross-parity stripes on a storage medium is provided. The apparatus and method may operate on data symbols having sizes greater than a data bit. The apparatus and method makes use of a plurality of parity stripes for reconstructing missing data stripes. The parity symbol values in the parity stripes are used as a basis for determining the value of the missing data symbol in a data stripe. A correction matrix is shifted along the data stripes, correcting missing data symbols as it is shifted. The correction is performed from the outside data stripes towards the inner data stripes to thereby use previously reconstructed data symbols to reconstruct other missing data symbols.

  13. Implementation of Open and Closed Kinetic Chain Quadriceps Strengthening Exercises after Anterior Cruciate Ligament Reconstruction.

    ERIC Educational Resources Information Center

    Ross, Michael D.; Denegar, Craig R.; Winzenried, Jay A.

    2001-01-01

    Reviews the effects of open kinetic chain (OKC) and closed kinetic chain (CKC) exercise on anterior cruciate ligament (ACL) strain and patellofemoral joint stress, suggesting a combination of the two for quadriceps strengthening after ACL reconstruction. Both OKC and CKC exercises may be modified and implemented for quadriceps strengthening after…

  14. Compensation for acoustic heterogeneities in photoacoustic computed tomography using a variable temporal data truncation reconstruction method

    NASA Astrophysics Data System (ADS)

    Poudel, Joemini; Matthews, Thomas P.; Anastasio, Mark A.; Wang, Lihong V.

    2016-03-01

    Photoacoustic computed tomography (PACT) is an emerging computed imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the absorbed optical energy density within tissue. If the object possesses spatially variant acoustic properties that are unaccounted for by the reconstruction algorithm, the estimated image can contain distortions. While reconstruction algorithms have recently been developed for compensating for this effect, they generally require the objects acoustic properties to be known a priori. To circumvent the need for detailed information regarding an objects acoustic properties, we have previously proposed a half-time reconstruction method for PACT. A half-time reconstruction method estimates the PACT image from a data set that has been temporally truncated to exclude the data components that have been strongly aberrated. In this approach, the degree of temporal truncation is the same for all measurements. However, this strategy can be improved upon it when the approximate sizes and locations of strongly heterogeneous structures such as gas voids or bones are known. In this work, we investigate PACT reconstruction algorithms that are based on a variable temporal data truncation (VTDT) approach that represents a generalization of the half-time reconstruction approach. In the VTDT approach, the degree of temporal truncation for each measurement is determined by the distance between the corresponding transducer location and the nearest known bone or gas void location. Reconstructed images from a numerical phantom is employed to demonstrate the feasibility and effectiveness of the approach.

  15. New methods for the computer-assisted 3-D reconstruction of neurons from confocal image stacks.

    PubMed

    Schmitt, Stephan; Evers, Jan Felix; Duch, Carsten; Scholz, Michael; Obermayer, Klaus

    2004-12-01

    Exact geometrical reconstructions of neuronal architecture are indispensable for the investigation of neuronal function. Neuronal shape is important for the wiring of networks, and dendritic architecture strongly affects neuronal integration and firing properties as demonstrated by modeling approaches. Confocal microscopy allows to scan neurons with submicron resolution. However, it is still a tedious task to reconstruct complex dendritic trees with fine structures just above voxel resolution. We present a framework assisting the reconstruction. User time investment is strongly reduced by automatic methods, which fit a skeleton and a surface to the data, while the user can interact and thus keeps full control to ensure a high quality reconstruction. The reconstruction process composes a successive gain of metric parameters. First, a structural description of the neuron is built, including the topology and the exact dendritic lengths and diameters. We use generalized cylinders with circular cross sections. The user provides a rough initialization by marking the branching points. The axes and radii are fitted to the data by minimizing an energy functional, which is regularized by a smoothness constraint. The investigation of proximity to other structures throughout dendritic trees requires a precise surface reconstruction. In order to achieve accuracy of 0.1 microm and below, we additionally implemented a segmentation algorithm based on geodesic active contours that allow for arbitrary cross sections and uses locally adapted thresholds. In summary, this new reconstruction tool saves time and increases quality as compared to other methods, which have previously been applied to real neurons.

  16. FUNCTIONAL PERFORMANCE AND KNEE LAXITY IN NORMAL INDIVIDUALS AND IN INDIVIDUALS SUBMITTED TO ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

    PubMed Central

    de Vasconcelos, Rodrigo Antunes; Bevilaqua-Grossi, Débora; Shimano, Antonio Carlos; Jansen Paccola, Cleber Antonio; Salvini, Tânia Fátima; Prado, Christiane Lanatovits; Mello Junior, Wilson A.

    2015-01-01

    The aim of this study was to analyze the correlation between deficits in the isokinetic peak torque of the knee extensors and flexors with hop tests, postoperative knee laxity and functional scores in normal and ACL- reconstructed subjects with patellar tendon and hamstring tendon autografts. Methods: Sixty male subjects were enrolled and subdivided into three groups: Twenty subjects without knee injuries (GC group) and two groups of 20 subjects submitted to ACL reconstruction with patellar tendon (GTP group) and hamstrings autograft (GTF group). Results: The results showed significant correlation between knee extensors peak torque and performance in the hop tests for GTF and GC groups. There are no significantly correlations between post op knee laxity and Lysholm score compared with the hop tests and peak torque deficits. Concerning the differences between groups, the GTP group showed greater peak torque deficits in knee extensors, worst Lysholm scores and higher percentage of individuals with lower limb symmetry index (ISM) < 90% in both hop tests when compared to the other two groups. Conclusion: It is not recommendable to use only one measurement instrument for the functional evaluation of ACL-reconstructed patients, because significant correlation between peak torque, subject's functional score, knee laxity and hop tests were not observed in all groups. PMID:26998464

  17. Adaptive Forward Modeling Method for Analysis and Reconstructions of Orientation Image Map

    SciTech Connect

    Frankie Li, Shiu Fai

    2014-06-01

    IceNine is a MPI-parallel orientation reconstruction and microstructure analysis code. It's primary purpose is to reconstruct a spatially resolved orientation map given a set of diffraction images from a high energy x-ray diffraction microscopy (HEDM) experiment (1). In particular, IceNine implements the adaptive version of the forward modeling method (2, 3). Part of IceNine is a library used to for conbined analysis of the microstructure with the experimentally measured diffraction signal. The libraries is also designed for tapid prototyping of new reconstruction and analysis algorithms. IceNine is also built with a simulator of diffraction images with an input microstructure.

  18. Addition of Autologous Mesenchymal Stem Cells to Whole Blood for Bio-Enhanced ACL Repair has No Benefit in the Porcine Model

    PubMed Central

    Proffen, Benedikt L.; Vavken, Patrick; Haslauer, Carla M.; Fleming, Braden C.; Harris, Chad E.; Machan, Jason T.; Murray, Martha M.

    2015-01-01

    Background Co-culture of mesenchymal stem cells (MSCs) from the retropatellar fat pad and peripheral blood has been shown to stimulate anterior cruciate ligament (ACL) fibroblast proliferation and collagen production in vitro. Current techniques of bio-enhanced ACL repair in animal studies involve adding a biologic scaffold, in this case an extracellular matrix based scaffold saturated with autologous whole blood, to a simple suture repair of the ligament. Whether the enrichment of whole blood with MSCs would further improve the in vivo results of bio-enhanced ACL repair was investigated. Hypothesis/Purpose The hypothesis was that the addition of MSCs derived from adipose tissue or peripheral blood to the blood-extracellular matrix composite, which is used in bio-enhanced ACL repair to stimulate healing, would improve the biomechanical properties of a bio-enhanced ACL repair after 15 weeks of healing. Study Design Controlled laboratory study. Methods Twenty-four adolescent Yucatan mini-pigs underwent ACL transection followed by: 1) bio-enhanced ACL repair, 2) bio-enhanced ACL repair with the addition of autologous adipose-derived MSCs and 3) bio-enhanced ACL repair with the addition of autologous peripheral blood derived MSCs. After fifteen weeks of healing, structural properties of the ACL (yield & failure load, linear stiffness) were measured. Cell and vascular density were measured in the repaired ACL via histology, and its tissue structure was qualitatively evaluated using the Advanced Ligament Maturity Index. Results After fifteen weeks of healing, there were no significant improvements in the biomechanical or histological properties with the addition of adipose-derived MSCs. The only significant change with the addition of peripheral blood MSCs was an increase in knee anteroposterior (AP) laxity when measured at 30 degrees of flexion. Conclusions These findings suggest that the addition of adipose or peripheral blood MSCs to whole blood prior to saturation of

  19. A new skin flap method for total auricular reconstruction in microtia patients with a reconstructed ear canal: extended scalp and extended mastoid postauricular skin flaps.

    PubMed

    Hwang, Euna; Kim, Young Soo; Chung, Seum

    2014-06-01

    Before visiting a plastic surgeon, some microtia patients may undergo canaloplasty for hearing improvement. In such cases, scarred tissues and the reconstructed external auditory canal in the postauricular area may cause a significant limitation in using the posterior auricular skin flap for ear reconstruction. In this article, we present a new method for auricular reconstruction in microtia patients with previous canaloplasty. By dividing a postauricular skin flap into an upper scalp extended skin flap and a lower mastoid extended skin flap at the level of a reconstructed external auditory canal, the entire anterior surface of the auricular framework can be covered with the two extended postauricular skin flaps. The reconstructed ear shows good color match and texture, with the entire anterior surface of the reconstructed ear being resurfaced with the skin flaps. Clinical question/level of evidence; therapeutic level IV.

  20. [A method for reconstruction of the A1 retinaculum in the flexor pollicis longus sheath with extensor pollicis brevis tendon].

    PubMed

    Chmiel, Z

    1996-01-01

    An original method for A1 retinaculum reconstruction of flexor pollicis longus sheath with extensor pollicis brevis tendon is presented. Reconstructed retinaculum is very strong. Loss of extensor pollicis brevis did not impaired thumb function.

  1. A penalized linear and nonlinear combined conjugate gradient method for the reconstruction of fluorescence molecular tomography.

    PubMed

    Shang, Shang; Bai, Jing; Song, Xiaolei; Wang, Hongkai; Lau, Jaclyn

    2007-01-01

    Conjugate gradient method is verified to be efficient for nonlinear optimization problems of large-dimension data. In this paper, a penalized linear and nonlinear combined conjugate gradient method for the reconstruction of fluorescence molecular tomography (FMT) is presented. The algorithm combines the linear conjugate gradient method and the nonlinear conjugate gradient method together based on a restart strategy, in order to take advantage of the two kinds of conjugate gradient methods and compensate for the disadvantages. A quadratic penalty method is adopted to gain a nonnegative constraint and reduce the illposedness of the problem. Simulation studies show that the presented algorithm is accurate, stable, and fast. It has a better performance than the conventional conjugate gradient-based reconstruction algorithms. It offers an effective approach to reconstruct fluorochrome information for FMT.

  2. DETECTORS AND EXPERIMENTAL METHODS: Decay vertex reconstruction and 3-dimensional lifetime determination at BESIII

    NASA Astrophysics Data System (ADS)

    Xu, Min; He, Kang-Lin; Zhang, Zi-Ping; Wang, Yi-Fang; Bian, Jian-Ming; Cao, Guo-Fu; Cao, Xue-Xiang; Chen, Shen-Jian; Deng, Zi-Yan; Fu, Cheng-Dong; Gao, Yuan-Ning; Han, Lei; Han, Shao-Qing; He, Miao; Hu, Ji-Feng; Hu, Xiao-Wei; Huang, Bin; Huang, Xing-Tao; Jia, Lu-Kui; Ji, Xiao-Bin; Li, Hai-Bo; Li, Wei-Dong; Liang, Yu-Tie; Liu, Chun-Xiu; Liu, Huai-Min; Liu, Ying; Liu, Yong; Luo, Tao; Lü, Qi-Wen; Ma, Qiu-Mei; Ma, Xiang; Mao, Ya-Jun; Mao, Ze-Pu; Mo, Xiao-Hu; Ning, Fei-Peng; Ping, Rong-Gang; Qiu, Jin-Fa; Song, Wen-Bo; Sun, Sheng-Sen; Sun, Xiao-Dong; Sun, Yong-Zhao; Tian, Hao-Lai; Wang, Ji-Ke; Wang, Liang-Liang; Wen, Shuo-Pin; Wu, Ling-Hui; Wu, Zhi; Xie, Yu-Guang; Yan, Jie; Yan, Liang; Yao, Jian; Yuan, Chang-Zheng; Yuan, Ye; Zhang, Chang-Chun; Zhang, Jian-Yong; Zhang, Lei; Zhang, Xue-Yao; Zhang, Yao; Zheng, Yang-Heng; Zhu, Yong-Sheng; Zou, Jia-Heng

    2009-06-01

    This paper focuses mainly on the vertex reconstruction of resonance particles with a relatively long lifetime such as K0S, Λ, as well as on lifetime measurements using a 3-dimensional fit. The kinematic constraints between the production and decay vertices and the decay vertex fitting algorithm based on the least squares method are both presented. Reconstruction efficiencies including experimental resolutions are discussed. The results and systematic errors are calculated based on a Monte Carlo simulation.

  3. Novel l2,1-norm optimization method for fluorescence molecular tomography reconstruction

    PubMed Central

    Jiang, Shixin; Liu, Jie; An, Yu; Zhang, Guanglei; Ye, Jinzuo; Mao, Yamin; He, Kunshan; Chi, Chongwei; Tian, Jie

    2016-01-01

    Fluorescence molecular tomography (FMT) is a promising tomographic method in preclinical research, which enables noninvasive real-time three-dimensional (3-D) visualization for in vivo studies. The ill-posedness of the FMT reconstruction problem is one of the many challenges in the studies of FMT. In this paper, we propose a l2,1-norm optimization method using a priori information, mainly the structured sparsity of the fluorescent regions for FMT reconstruction. Compared to standard sparsity methods, the structured sparsity methods are often superior in reconstruction accuracy since the structured sparsity utilizes correlations or structures of the reconstructed image. To solve the problem effectively, the Nesterov’s method was used to accelerate the computation. To evaluate the performance of the proposed l2,1-norm method, numerical phantom experiments and in vivo mouse experiments are conducted. The results show that the proposed method not only achieves accurate and desirable fluorescent source reconstruction, but also demonstrates enhanced robustness to noise. PMID:27375949

  4. Automatic Carrier Landing System (ACLS) Category 3 Certification Manual

    DTIC Science & Technology

    1982-07-01

    INSTRUMENT LANDING SYSTEM .... ......... J-1 APPENDIX K: FRESNEL LENS OPTICAL LANDING SYSTEM .. ......... K-I APPENDIX L: PILOT ACLS RATINGS...surface elements of the ACLS consist of the AN/SPN-42A Landing Control Central with the AN/SPN-41 Instrument Landing System and Fresnel Lens Optical...radar antennas. c. The Fresnel lens calibration pole and three hand held radios be provided. d. Instrumentation seivicing and recording playback

  5. An adaptive total variation image reconstruction method for speckles through disordered media

    NASA Astrophysics Data System (ADS)

    Gong, Changmei; Shao, Xiaopeng; Wu, Tengfei

    2013-09-01

    Multiple scattering of light in highly disordered medium can break the diffraction limit of conventional optical system combined with image reconstruction method. Once the transmission matrix of the imaging system is obtained, the target image can be reconstructed from its speckle pattern by image reconstruction algorithm. Nevertheless, the restored image attained by common image reconstruction algorithms such as Tikhonov regularization has a relatively low signal-tonoise ratio (SNR) due to the experimental noise and reconstruction noise, greatly reducing the quality of the result image. In this paper, the speckle pattern of the test image is simulated by the combination of light propagation theories and statistical optics theories. Subsequently, an adaptive total variation (ATV) algorithm—the TV minimization by augmented Lagrangian and alternating direction algorithms (TVAL3), which is based on augmented Lagrangian and alternating direction algorithm, is utilized to reconstruct the target image. Numerical simulation experimental results show that, the TVAL3 algorithm can effectively suppress the noise of the restored image and preserve more image details, thus greatly boosts the SNR of the restored image. It also indicates that, compared with the image directly formed by `clean' system, the reconstructed results can overcoming the diffraction limit of the `clean' system, therefore being conductive to the observation of cells and protein molecules in biological tissues and other structures in micro/nano scale.

  6. A Reconstructed Discontinuous Galerkin Method for the Compressible Euler Equations on Arbitrary Grids

    SciTech Connect

    Hong Luo; Luquing Luo; Robert Nourgaliev; Vincent Mousseau

    2009-06-01

    A reconstruction-based discontinuous Galerkin (DG) method is presented for the solution of the compressible Euler equations on arbitrary grids. By taking advantage of handily available and yet invaluable information, namely the derivatives, in the context of the discontinuous Galerkin methods, a solution polynomial of one degree higher is reconstructed using a least-squares method. The stencils used in the reconstruction involve only the van Neumann neighborhood (face-neighboring cells) and are compact and consistent with the underlying DG method. The resulting DG method can be regarded as an improvement of a recovery-based DG method in the sense that it shares the same nice features as the recovery-based DG method, such as high accuracy and efficiency, and yet overcomes some of its shortcomings such as a lack of flexibility, compactness, and robustness. The developed DG method is used to compute a variety of flow problems on arbitrary meshes to demonstrate the accuracy and efficiency of the method. The numerical results indicate that this reconstructed DG method is able to obtain a third-order accurate solution at a slightly higher cost than its second-order DG method and provide an increase in performance over the third order DG method in terms of computing time and storage requirement.

  7. A novel digital tomosynthesis (DTS) reconstruction method using a deformation field map.

    PubMed

    Ren, Lei; Zhang, Junan; Thongphiew, Danthai; Godfrey, Devon J; Wu, Q Jackie; Zhou, Su-Min; Yin, Fang-Fang

    2008-07-01

    We developed a novel digital tomosynthesis (DTS) reconstruction method using a deformation field map to optimally estimate volumetric information in DTS images. The deformation field map is solved by using prior information, a deformation model, and new projection data. Patients' previous cone-beam CT (CBCT) or planning CT data are used as the prior information, and the new patient volume to be reconstructed is considered as a deformation of the prior patient volume. The deformation field is solved by minimizing bending energy and maintaining new projection data fidelity using a nonlinear conjugate gradient method. The new patient DTS volume is then obtained by deforming the prior patient CBCT or CT volume according to the solution to the deformation field. This method is novel because it is the first method to combine deformable registration with limited angle image reconstruction. The method was tested in 2D cases using simulated projections of a Shepp-Logan phantom, liver, and head-and-neck patient data. The accuracy of the reconstruction was evaluated by comparing both organ volume and pixel value differences between DTS and CBCT images. In the Shepp-Logan phantom study, the reconstructed pixel signal-to-noise ratio (PSNR) for the 60 degrees DTS image reached 34.3 dB. In the liver patient study, the relative error of the liver volume reconstructed using 60 degrees projections was 3.4%. The reconstructed PSNR for the 60 degrees DTS image reached 23.5 dB. In the head-and-neck patient study, the new method using 60 degrees projections was able to reconstruct the 8.1 degrees rotation of the bony structure with 0.0 degrees error. The reconstructed PSNR for the 60 degrees DTS image reached 24.2 dB. In summary, the new reconstruction method can optimally estimate the volumetric information in DTS images using 60 degrees projections. Preliminary validation of the algorithm showed that it is both technically and clinically feasible for image guidance in radiation

  8. Reducing the effects of acoustic heterogeneity with an iterative reconstruction method from experimental data in microwave induced thermoacoustic tomography

    SciTech Connect

    Wang, Jinguo; Zhao, Zhiqin Song, Jian; Chen, Guoping; Nie, Zaiping; Liu, Qing-Huo

    2015-05-15

    Purpose: An iterative reconstruction method has been previously reported by the authors of this paper. However, the iterative reconstruction method was demonstrated by solely using the numerical simulations. It is essential to apply the iterative reconstruction method to practice conditions. The objective of this work is to validate the capability of the iterative reconstruction method for reducing the effects of acoustic heterogeneity with the experimental data in microwave induced thermoacoustic tomography. Methods: Most existing reconstruction methods need to combine the ultrasonic measurement technology to quantitatively measure the velocity distribution of heterogeneity, which increases the system complexity. Different to existing reconstruction methods, the iterative reconstruction method combines time reversal mirror technique, fast marching method, and simultaneous algebraic reconstruction technique to iteratively estimate the velocity distribution of heterogeneous tissue by solely using the measured data. Then, the estimated velocity distribution is used subsequently to reconstruct the highly accurate image of microwave absorption distribution. Experiments that a target placed in an acoustic heterogeneous environment are performed to validate the iterative reconstruction method. Results: By using the estimated velocity distribution, the target in an acoustic heterogeneous environment can be reconstructed with better shape and higher image contrast than targets that are reconstructed with a homogeneous velocity distribution. Conclusions: The distortions caused by the acoustic heterogeneity can be efficiently corrected by utilizing the velocity distribution estimated by the iterative reconstruction method. The advantage of the iterative reconstruction method over the existing correction methods is that it is successful in improving the quality of the image of microwave absorption distribution without increasing the system complexity.

  9. A Reconstructed Discontinuous Galerkin Method for the Compressible Navier-Stokes Equations on Arbitrary Grids

    SciTech Connect

    Hong Luo; Luqing Luo; Robert Nourgaliev; Vincent A. Mousseau

    2010-09-01

    A reconstruction-based discontinuous Galerkin (RDG) method is presented for the solution of the compressible Navier–Stokes equations on arbitrary grids. The RDG method, originally developed for the compressible Euler equations, is extended to discretize viscous and heat fluxes in the Navier–Stokes equations using a so-called inter-cell reconstruction, where a smooth solution is locally reconstructed using a least-squares method from the underlying discontinuous DG solution. Similar to the recovery-based DG (rDG) methods, this reconstructed DG method eliminates the introduction of ad hoc penalty or coupling terms commonly found in traditional DG methods. Unlike rDG methods, this RDG method does not need to judiciously choose a proper form of a recovered polynomial, thus is simple, flexible, and robust, and can be used on arbitrary grids. The developed RDG method is used to compute a variety of flow problems on arbitrary meshes to demonstrate its accuracy, efficiency, robustness, and versatility. The numerical results indicate that this RDG method is able to deliver the same accuracy as the well-known Bassi–Rebay II scheme, at a half of its computing costs for the discretization of the viscous fluxes in the Navier–Stokes equations, clearly demonstrating its superior performance over the existing DG methods for solving the compressible Navier–Stokes equations.

  10. A Reconstructed Discontinuous Galerkin Method for the Compressible Navier-Stokes Equations on Arbitrary Grids

    SciTech Connect

    Hong Luo; Luqing Luo; Robert Nourgaliev; Vincent A. Mousseau

    2010-01-01

    A reconstruction-based discontinuous Galerkin (RDG) method is presented for the solution of the compressible Navier-Stokes equations on arbitrary grids. The RDG method, originally developed for the compressible Euler equations, is extended to discretize viscous and heat fluxes in the Navier-Stokes equations using a so-called inter-cell reconstruction, where a smooth solution is locally reconstructed using a least-squares method from the underlying discontinuous DG solution. Similar to the recovery-based DG (rDG) methods, this reconstructed DG method eliminates the introduction of ad hoc penalty or coupling terms commonly found in traditional DG methods. Unlike rDG methods, this RDG method does not need to judiciously choose a proper form of a recovered polynomial, thus is simple, flexible, and robust, and can be used on arbitrary grids. The developed RDG method is used to compute a variety of flow problems on arbitrary meshes to demonstrate its accuracy, efficiency, robustness, and versatility. The numerical results indicate that this RDG method is able to deliver the same accuracy as the well-known Bassi-Rebay II scheme, at a half of its computing costs for the discretization of the viscous fluxes in the Navier-Stokes equations, clearly demonstrating its superior performance over the existing DG methods for solving the compressible Navier-Stokes equations.

  11. Functional results from reconstruction of the anterior cruciate ligament using the central third of the patellar ligament and flexor tendons☆

    PubMed Central

    de Souza Leao, Marcos George; Pampolha, Abelardo Gautama Moreira; Orlando Junior, Nilton

    2015-01-01

    Objectives To evaluate knee function in patients undergoing reconstruction of the anterior cruciate ligament (ACL) using the central third of the patellar ligament or the medial flexor tendons of the knee, i.e. quadruple ligaments from the semitendinosus and gracilis (ST-G), by means of the Knee Society Score (KSS) and the Lysholm scale. Methods This was a randomized prospective longitudinal study on 40 patients who underwent arthroscopic ACL reconstruction between September 2013 and August 2014. They comprised 37 males and three females, with ages ranging from 16 to 52 years. The patients were numbered randomly from 1 to 40: the even numbers underwent surgical correction using the ST-G tendons and the odd numbers, using the patellar tendon. Functional evaluations were made using the KSS and Lysholm scale, applied in the evening before the surgical procedure and six months after the operation. Results From the statistical analysis, it could be seen that the patients’ functional capacity was significantly greater after the operation than before the operation. There was strong evidence that the two forms of therapy had similar results (p = >0.05), in all the comparisons. Conclusions The results from the ACL reconstructions were similar with regard to functional recovery of the knee and improvement of quality of life, independent of the type of graft. It was not possible to identify the best method of surgical treatment. The surgeon's clinical and technical experience and the patient are the factors that determine the choice of graft type for use in ACL surgery. PMID:27218084

  12. Hydrogel fibers for ACL prosthesis: design and mechanical evaluation of PVA and PVA/UHMWPE fiber constructs.

    PubMed

    Bach, Jason S; Detrez, Fabrice; Cherkaoui, Mohammed; Cantournet, Sabine; Ku, David N; Corté, Laurent

    2013-05-31

    Prosthetic devices for anterior cruciate ligament (ACL) reconstruction have been unsuccessful due to mechanical failure or chronic inflammation. Polymer hydrogels combine biocompatibility and unique low friction properties; however, their prior use for ligament reconstruction has been restricted to coatings due to insufficient tensile mechanics. Here, we investigate new constructs of polyvinyl alcohol (PVA) hydrogel fibers. In water, these fibers swell to an equilibrium water content of 50% by weight, retaining a tensile modulus greater than 40 MPa along the fiber axis at low strain. Rope constructs were assembled for ACL replacement and mechanical properties were compared with data from the literature. Pure PVA hydrogel constructs closely reproduce the non-linear tensile stiffness of the native ACL with an ultimate strength of about 2000 N. An additional safety factor in tensile strength was achieved with composite braids by adding ultrahigh molecular weight polyethylene (UHMWPE) fibers around a core of PVA cords. Composition and braiding angle are adjusted to produce a non-linear tensile behavior within the range of the native ligament that can be predicted by a simple rope model. This design was found to sustain over one million cycles between 50 and 450 N with limited damage and less than 20% creep. The promising mechanical performances of these systems provide justification for more extensive in vivo evaluation.

  13. Knee Kinematics During Non-contact ACL Injury as Determined from Bone Bruise Location

    PubMed Central

    Kim, Sophia Y.; Spritzer, Charles E.; Utturkar, Gangadhar M.; Toth, Alison P.; Garrett, William E.; DeFrate, Louis E.

    2015-01-01

    Background The motions causing non-contact ACL injury remain unclear. Tibiofemoral bone bruises are believed to be the result of joint impact near the time of ACL rupture. The locations and frequencies of these bone bruises have been reported, but there is limited data quantifying knee position and orientation near the time of injury based on these contusions. Hypothesis Knee position and orientation near the time of non-contact ACL injury include extension and anterior tibial translation. Study Design Descriptive Laboratory Study Methods Magnetic resonance (MR) images of eight subjects with non-contact ACL injuries were acquired within one month of injury and subsequently analyzed. All subjects exhibited bruises on both the femur and tibia in both medial and lateral compartments. The outer margins of bone and the bone bruise surfaces were outlined on each image to create a 3D model of each subject’s knee in its position during MR imaging (MRI position). Numerical optimization was used to maximize overlap of the bone bruises on the femur and tibia and predict the position of injury. Flexion angle, valgus orientation, internal tibial rotation, and anterior tibial translation were measured in both the MRI position and the predicted position of injury. Differences in kinematics between the MRI position, which served as an unloaded reference, and the predicted position of injury were compared using paired t-tests. Results Flexion angle was near full extension in both the MRI position and the predicted position of injury (8° versus 12°, p=0.2). Statistically significant increases in valgus orientation (5°, p=0.003), internal tibial rotation (15°, p=0.003), and anterior tibial translation (22mm, p<0.001) were observed in the predicted position of injury relative to the MRI position. Conclusions These results suggest that for the bone bruise pattern studied, landing on an extended knee is high risk for ACL injury. Extension was accompanied by increased anterior

  14. Application of x-ray direct methods to surface reconstructions: The solution of projected superstructures

    NASA Astrophysics Data System (ADS)

    Torrelles, X.; Rius, J.; Boscherini, F.; Heun, S.; Mueller, B. H.; Ferrer, S.; Alvarez, J.; Miravitlles, C.

    1998-02-01

    The projections of surface reconstructions are normally solved from the interatomic vectors found in two-dimensional Patterson maps computed with the intensities of the in-plane superstructure reflections. Since for difficult reconstructions this procedure is not trivial, an alternative automated one based on the ``direct methods'' sum function [Rius, Miravitlles, and Allmann, Acta Crystallogr. A52, 634 (1996)] is shown. It has been applied successfully to the known c(4×2) reconstruction of Ge(001) and to the so-far unresolved In0.04Ga0.96As (001) p(4×2) surface reconstruction. For this last system we propose a modification of one of the models previously proposed for GaAs(001) whose characteristic feature is the presence of dimers along the fourfold direction.

  15. Free flaps in orbital exenteration: a safe and effective method for reconstruction.

    PubMed

    López, Fernando; Suárez, Carlos; Carnero, Susana; Martín, Clara; Camporro, Daniel; Llorente, José L

    2013-05-01

    The aim of this study was to investigate the course of reconstructive treatment and outcomes with use of free flaps after orbital exenteration for malignancy. Charts of patients who had free flap reconstruction after orbital exenteration were retrospectively reviewed and the surgical technique was evaluated. Demographics, histology, surgical management, complications, locoregional control, and survival were analyzed. We performed 22 flaps in 21 patients. Reconstruction was undertaken mainly with anterolateral thigh (56 %), radial forearm (22 %), or parascapular (22 %) free flaps. Complications occurred in 33 % of patients and the flap's success rate was 91 %. The 5-year locoregional control and survival rates were 42 and 37 %, respectively. Free tissue transfer is a reliable, safe, and effective method for repair of defects of the orbit and periorbital structures resulting from oncologic resection. The anterolateral thigh flap is a versatile option to reconstruct the many orbital defects encountered.

  16. Gender Dimorphic ACL Strain In Response to Combined Dynamic 3D Knee Joint Loading: Implications for ACL Injury Risk

    PubMed Central

    Mizuno, Kiyonori; Andrish, Jack T.; van den Bogert, Antonie J.; McLean, Scott G.

    2009-01-01

    While gender-based differences in knee joint anatomies/laxities are well documented, the potential for them to precipitate gender-dimorphic ACL loading and resultant injury risk has not been considered. To this end, we generated gender-specific models of ACL strain as a function of any six degrees of freedom (6DOF) knee joint load state via a combined cadaveric and analytical approach. Continuously varying joint forces and torques were applied to five male and five female cadaveric specimens and recorded along with synchronous knee flexion and ACL strain data. All data (~10,000 samples) were submitted to specimen-specific regression analyses, affording ACL strain predictions as a function of the combined 6 DOF knee loads. Following individual model verifications, generalized gender-specific models were generated and subjected to 6 DOF external load scenarios consistent with both a clinical examination and a dynamic sports maneuver. The ensuing model-based strain predictions were subsequently examined for gender-based discrepancies. Male and female specimen specific models predicted ACL strain within 0.51% ± 0.10% and 0.52% ± 0.07% of the measured data respectively, and explained more than 75% of the associated variance in each case. Predicted female ACL strains were also significantly larger than respective male values for both of simulated 6 DOF load scenarios. Outcomes suggest that the female ACL will rupture in response to comparatively smaller external load applications. Future work must address the underlying anatomical/laxity contributions to knee joint mechanical and resultant ACL loading, ultimately affording prevention strategies that may cater to individual joint vulnerabilities. PMID:19464897

  17. Amiodarone for ACLS: a critical evaluation.

    PubMed

    Stewart, C E

    2001-09-01

    Years ago, William Osler taught physicians, "Be not the first nor the last to adopt a therapy." This continues to be sage advice. Clinicians should be cautious in considering the use of amiodarone in a field setting for cardiac arrest until studies clearly show a benefit over drugs currently in use. The endpoint of the only cardiac arrest study available shows improved survival when amiodarone is combined with other drugs over placebo until the patient gets to the emergency department, but is not a comparison with other current drugs nor had any effect on long-term survival or functioning neurologic status. As previously cited, amiodarone was comparable with bretylium in treating recurrent VT/VF in one controlled study. Further study of this and other ACLS drugs is imperative. In summary, amiodarone should be reclassified as either a class indeterminate agent when used alone ("no harm but no benefit ... evidence insufficient to support final class decision") or a class IIb agent ("acceptable and useful ... supported by fair to good evidence") when used in addition to other therapies in the treatment of ventricular fibrillation and pulseless ventricular tachycardia. There is not sufficient evidence to move amiodarone to first-line therapy in the "out-of-hospital" cardiac arrest. This evidence may be available in the future and would then change this recommendation.

  18. Noninvasive reconstruction of cardiac transmembrane potentials using a kernelized extreme learning method

    NASA Astrophysics Data System (ADS)

    Jiang, Mingfeng; Zhang, Heng; Zhu, Lingyan; Cao, Li; Wang, Yaming; Xia, Ling; Gong, Yinglan

    2015-04-01

    Non-invasively reconstructing the cardiac transmembrane potentials (TMPs) from body surface potentials can act as a regression problem. The support vector regression (SVR) method is often used to solve the regression problem, however the computational complexity of the SVR training algorithm is usually intensive. In this paper, another learning algorithm, termed as extreme learning machine (ELM), is proposed to reconstruct the cardiac transmembrane potentials. Moreover, ELM can be extended to single-hidden layer feed forward neural networks with kernel matrix (kernelized ELM), which can achieve a good generalization performance at a fast learning speed. Based on the realistic heart-torso models, a normal and two abnormal ventricular activation cases are applied for training and testing the regression model. The experimental results show that the ELM method can perform a better regression ability than the single SVR method in terms of the TMPs reconstruction accuracy and reconstruction speed. Moreover, compared with the ELM method, the kernelized ELM method features a good approximation and generalization ability when reconstructing the TMPs.

  19. Image reconstruction in EIT with unreliable electrode data using random sample consensus method

    NASA Astrophysics Data System (ADS)

    Jeon, Min Ho; Khambampati, Anil Kumar; Kim, Bong Seok; In Kang, Suk; Kim, Kyung Youn

    2017-04-01

    In electrical impedance tomography (EIT), it is important to acquire reliable measurement data through EIT system for achieving good reconstructed image. In order to have reliable data, various methods for checking and optimizing the EIT measurement system have been studied. However, most of the methods involve additional cost for testing and the measurement setup is often evaluated before the experiment. It is useful to have a method which can detect the faulty electrode data during the experiment without any additional cost. This paper presents a method based on random sample consensus (RANSAC) to find the incorrect data on fault electrode in EIT data. RANSAC is a curve fitting method that removes the outlier data from measurement data. RANSAC method is applied with Gauss Newton (GN) method for image reconstruction of human thorax with faulty data. Numerical and phantom experiments are performed and the reconstruction performance of the proposed RANSAC method with GN is compared with conventional GN method. From the results, it can be noticed that RANSAC with GN has better reconstruction performance than conventional GN method with faulty electrode data.

  20. Hip and knee joint kinematics during a diagonal jump landing in anterior cruciate ligament reconstructed females.

    PubMed

    Delahunt, Eamonn; Prendiville, Anna; Sweeney, Lauren; Chawke, Mark; Kelleher, Judy; Patterson, Matt; Murphy, Katie

    2012-08-01

    Anterior cruciate ligament (ACL) injury is a common injury encountered by sport medicine clinicians. Surgical reconstruction is the recommended treatment of choice for those athletes wishing to return to full-contact sports participation and for sports requiring multi-directional movement patterns. The aim of ACL reconstruction is to restore knee joint mechanical stability such that the athlete can return to sporting participation. However, knowledge regarding the extent to which lower limb kinematic profiles are restored following ACL reconstruction is limited. In the present study the hip and knee joint kinematic profiles of 13 ACL reconstructed (ACL-R) and 16 non-injured control subjects were investigated during the performance of a diagonal jump landing task. The ACL-R group exhibited significantly less peak knee joint flexion (P=0.01). Significant between group differences were noted for time averaged hip joint sagittal plane (P<0.05) and transverse plane (P<0.05) kinematic profiles, as well as knee joint frontal plane (P<0.05) and sagittal plane (P<0.05) kinematic profiles. These results suggest that aberrant hip and knee joint kinematic profiles are present following ACL reconstruction, which could influence future injury risk.

  1. DETECTORS AND EXPERIMENTAL METHODS Study of low momentum track reconstruction for the BESIII main drift chamber

    NASA Astrophysics Data System (ADS)

    Jia, Lu-Kui; Mao, Ze-Pu; Li, Wei-Dong; Cao, Guo-Fu; Cao, Xue-Xiang; Deng, Zi-Yan; He, Kang-Lin; Liu, Chun-Yan; Liu, Huai-Min; Liu, Qiu-Guang; Ma, Qiu-Mei; Ma, Xiang; Qiu, Jin-Fa; Tian, Hao-Lai; Wang, Ji-Ke; Wu, Ling-Hui; Yuan, Ye; Zang, Shi-Lei; Zhang, Chang-Chun; Zhang, Lei; Zhang, Yao; Zhu, Kai; Zou, Jia-Heng

    2010-12-01

    In order to overcome the difficulty brought by the circling charged tracks with transverse momentum less than 120 MeV in the BESIII Main Drift Chamber (MDC), a specialized method called TCurlFinder was developed. This tracking method focuses on the charged track reconstruction under 120 MeV and possesses a special mechanism to reject background noise hits. The performance of the package has been carefully checked and tuned by both Monte Carlo data and real data. The study shows that this tracking method could obviously enhance the reconstruction efficiency in the low transverse momentum region, providing physics analysis with more and reliable data.

  2. An Ecological Study of Anterior Cruciate Ligament Reconstruction, Part 2

    PubMed Central

    McGrath, Timothy M.; Waddington, Gordon; Scarvell, Jennie M.; Ball, Nick; Creer, Rob; Woods, Kevin; Smith, Damian; Adams, Roger

    2017-01-01

    Background: Additional high-quality prospective studies are needed to better define the objective criteria used in relation to return-to-sport decisions after anterior cruciate ligament (ACL) reconstruction in active populations. Purpose: To investigate prospectively the relationship between functional performance test results at 24 weeks postoperative and return-to-sport activity (Tegner activity score) at 12 and 24 months, respectively, after synthetic (ligament advanced reinforcement system [LARS]) and autograft (doubled semitendinosus/gracilis [2ST/2GR]) ACL reconstructions. Study Design: Case series; Level of evidence, 4. Methods: A total of 64 patients who underwent ACL reconstruction (32 LARS, 32 2ST/2GR autograft; mean age, 27.9 years; body mass index [BMI], 24.9 kg/m2) were assessed preoperatively and at staged intervals postoperatively up to 24 weeks for isokinetic testing of quadriceps and hamstring average power per repetition at 60 deg/s and 180 deg/s, a battery of hop tests, peak vertical ground-reaction force (vGRF), and time to peak vGRF (in seconds) during a step- and jump-down task onto a force platform and peak speed (m/s) using a global positioning system (GPS unit) during a running task. A cohort of 32 healthy matched participants (mean age, 26.31 years; BMI, 25.7 kg/m2) were also tested to act as reference. Pearson correlation was calculated to assess correlation of each performance measure at 24 weeks postoperative with activity outcomes (Tegner score) at 12 and 24 months. Results: The strongest correlation between physical performance tests and return-to-sport outcomes was observed with peak speed during running. Large correlations were also observed for hamstring isokinetic power and hop test for distance. Moderate correlations were observed for timed hop, peak vGRF during a jump-down task, and quadriceps isokinetic power. No statistical correlations were observed for time to peak vGRF during a step-down and jump-down task as well as peak v

  3. Noise reduction in computed tomography using a multiplicative continuous-time image reconstruction method

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Yusaku; Kojima, Takeshi; Yoshinaga, Tetsuya

    2016-03-01

    In clinical X-ray computed tomography (CT), filtered back-projection as a transform method and iterative reconstruction such as the maximum-likelihood expectation-maximization (ML-EM) method are known methods to reconstruct tomographic images. As the other reconstruction method, we have presented a continuous-time image reconstruction (CIR) system described by a nonlinear dynamical system, based on the idea of continuous methods for solving tomographic inverse problems. Recently, we have also proposed a multiplicative CIR system described by differential equations based on the minimization of a weighted Kullback-Leibler divergence. We prove theoretically that the divergence measure decreases along the solution to the CIR system, for consistent inverse problems. In consideration of the noisy nature of projections in clinical CT, the inverse problem belongs to the category of ill-posed problems. The performance of a noise-reduction scheme for a new (previously developed) CIR system was investigated by means of numerical experiments using a circular phantom image. Compared to the conventional CIR and the ML-EM methods, the proposed CIR method has an advantage on noisy projection with lower signal-to-noise ratios in terms of the divergence measure on the actual image under the same common measure observed via the projection data. The results lead to the conclusion that the multiplicative CIR method is more effective and robust for noise reduction in CT compared to the ML-EM as well as conventional CIR methods.

  4. A Reconstructed Discontinuous Galerkin Method for the Compressible Flows on Unstructured Tetrahedral Grids

    SciTech Connect

    Hong Luo; Yidong Xia; Robert Nourgaliev; Chunpei Cai

    2011-06-01

    A reconstruction-based discontinuous Galerkin (RDG) method is presented for the solution of the compressible Navier-Stokes equations on unstructured tetrahedral grids. The RDG method, originally developed for the compressible Euler equations, is extended to discretize viscous and heat fluxes in the Navier-Stokes equations using a so-called inter-cell reconstruction, where a smooth solution is locally reconstructed using a least-squares method from the underlying discontinuous DG solution. Similar to the recovery-based DG (rDG) methods, this reconstructed DG method eliminates the introduction of ad hoc penalty or coupling terms commonly found in traditional DG methods. Unlike rDG methods, this RDG method does not need to judiciously choose a proper form of a recovered polynomial, thus is simple, flexible, and robust, and can be used on unstructured grids. The preliminary results indicate that this RDG method is stable on unstructured tetrahedral grids, and provides a viable and attractive alternative for the discretization of the viscous and heat fluxes in the Navier-Stokes equations.

  5. The Extratropical Northern Hemisphere Temperature Reconstruction during the Last Millennium Based on a Novel Method

    PubMed Central

    Xing, Pei; Chen, Xin; Luo, Yong; Nie, Suping; Zhao, Zongci; Huang, Jianbin; Wang, Shaowu

    2016-01-01

    Large-scale climate history of the past millennium reconstructed solely from tree-ring data is prone to underestimate the amplitude of low-frequency variability. In this paper, we aimed at solving this problem by utilizing a novel method termed “MDVM”, which was a combination of the ensemble empirical mode decomposition (EEMD) and variance matching techniques. We compiled a set of 211 tree-ring records from the extratropical Northern Hemisphere (30–90°N) in an effort to develop a new reconstruction of the annual mean temperature by the MDVM method. Among these dataset, a number of 126 records were screened out to reconstruct temperature variability longer than decadal scale for the period 850–2000 AD. The MDVM reconstruction depicted significant low-frequency variability in the past millennium with evident Medieval Warm Period (MWP) over the interval 950–1150 AD and pronounced Little Ice Age (LIA) cumulating in 1450–1850 AD. In the context of 1150-year reconstruction, the accelerating warming in 20th century was likely unprecedented, and the coldest decades appeared in the 1640s, 1600s and 1580s, whereas the warmest decades occurred in the 1990s, 1940s and 1930s. Additionally, the MDVM reconstruction covaried broadly with changes in natural radiative forcing, and especially showed distinct footprints of multiple volcanic eruptions in the last millennium. Comparisons of our results with previous reconstructions and model simulations showed the efficiency of the MDVM method on capturing low-frequency variability, particularly much colder signals of the LIA relative to the reference period. Our results demonstrated that the MDVM method has advantages in studying large-scale and low-frequency climate signals using pure tree-ring data. PMID:26751947

  6. Local and Non-local Regularization Techniques in Emission (PET/SPECT) Tomographic Image Reconstruction Methods.

    PubMed

    Ahmad, Munir; Shahzad, Tasawar; Masood, Khalid; Rashid, Khalid; Tanveer, Muhammad; Iqbal, Rabail; Hussain, Nasir; Shahid, Abubakar; Fazal-E-Aleem

    2016-06-01

    Emission tomographic image reconstruction is an ill-posed problem due to limited and noisy data and various image-degrading effects affecting the data and leads to noisy reconstructions. Explicit regularization, through iterative reconstruction methods, is considered better to compensate for reconstruction-based noise. Local smoothing and edge-preserving regularization methods can reduce reconstruction-based noise. However, these methods produce overly smoothed images or blocky artefacts in the final image because they can only exploit local image properties. Recently, non-local regularization techniques have been introduced, to overcome these problems, by incorporating geometrical global continuity and connectivity present in the objective image. These techniques can overcome drawbacks of local regularization methods; however, they also have certain limitations, such as choice of the regularization function, neighbourhood size or calibration of several empirical parameters involved. This work compares different local and non-local regularization techniques used in emission tomographic imaging in general and emission computed tomography in specific for improved quality of the resultant images.

  7. L{sub 1/2} regularization based numerical method for effective reconstruction of bioluminescence tomography

    SciTech Connect

    Chen, Xueli E-mail: jimleung@mail.xidian.edu.cn; Yang, Defu; Zhang, Qitan; Liang, Jimin E-mail: jimleung@mail.xidian.edu.cn

    2014-05-14

    Even though bioluminescence tomography (BLT) exhibits significant potential and wide applications in macroscopic imaging of small animals in vivo, the inverse reconstruction is still a tough problem that has plagued researchers in a related area. The ill-posedness of inverse reconstruction arises from insufficient measurements and modeling errors, so that the inverse reconstruction cannot be solved directly. In this study, an l{sub 1/2} regularization based numerical method was developed for effective reconstruction of BLT. In the method, the inverse reconstruction of BLT was constrained into an l{sub 1/2} regularization problem, and then the weighted interior-point algorithm (WIPA) was applied to solve the problem through transforming it into obtaining the solution of a series of l{sub 1} regularizers. The feasibility and effectiveness of the proposed method were demonstrated with numerical simulations on a digital mouse. Stability verification experiments further illustrated the robustness of the proposed method for different levels of Gaussian noise.

  8. A physics-based intravascular ultrasound image reconstruction method for lumen segmentation.

    PubMed

    Mendizabal-Ruiz, Gerardo; Kakadiaris, Ioannis A

    2016-08-01

    Intravascular ultrasound (IVUS) refers to the medical imaging technique consisting of a miniaturized ultrasound transducer located at the tip of a catheter that can be introduced in the blood vessels providing high-resolution, cross-sectional images of their interior. Current methods for the generation of an IVUS image reconstruction from radio frequency (RF) data do not account for the physics involved in the interaction between the IVUS ultrasound signal and the tissues of the vessel. In this paper, we present a novel method to generate an IVUS image reconstruction based on the use of a scattering model that considers the tissues of the vessel as a distribution of three-dimensional point scatterers. We evaluated the impact of employing the proposed IVUS image reconstruction method in the segmentation of the lumen/wall interface on 40MHz IVUS data using an existing automatic lumen segmentation method. We compared the results with those obtained using the B-mode reconstruction on 600 randomly selected frames from twelve pullback sequences acquired from rabbit aortas and different arteries of swine. Our results indicate the feasibility of employing the proposed IVUS image reconstruction for the segmentation of the lumen.

  9. Anterior cruciate ligament reconstruction using quadriceps tendon autograft for adolescents with open physes- a technical note

    PubMed Central

    2011-01-01

    Background One major concern in the treatment of ACL lesions in children and adolescents with open physes is the risk of iatrogenic damage to the physes and a possibly resulting growth disturbance. Purpose The primary purpose of this article is to describe our technique of a transphyseal ACL reconstruction using quadriceps tendon-bone autograft in children and adolescents with open growth plates. The secondary aim is to report our early results in terms of postoperative growth disturbances which are considered to be a major concern in this challenging group of patients. It was our hypothesis that with our proposed technique no significant growth disturbances would occur. Methods From January 1997 to December 2007 49 consecutive children and adolescents with open growth plates were treated for a torn ACL using the aforementioned surgical technique. The patients (28 males and 21 females) with a median age at surgery of 13 (range 8-15) years were retrospectively evaluated. Outcome measures were follow-up radiographs (weight-bearing long leg radiographs of the injured and uninjured knee, anteroposterior and lateral views, a tangential view of the patella and a tunnel view of the injured knee) and follow-up notes (6 weeks, 3, 6, 12 months and until closing of physes) for occurrence of any tibial and/or femoral growth changes. Results: All of the 49 patients had a sufficient clinical and radiological follow-up (minimum 5 years, rate 100%). 48 cases did not show any clinical and radiological growth disturbance. One case of growth disturbance in a 10.5 years old girl was observed. She developed a progressive valgus-flexion deformity which was attributed to a malplacement of the autograft bone block within the femoral posterolateral epiphyseal plate leading to an early localized growth stop. None of the patients were reoperated due to ACL graft failure. Five of the patients underwent revision ACL surgery due to another adequate sports trauma after the growth-stop. The

  10. Anterior cruciate ligament reconstruction: a look at prosthetics--past, present and possible future.

    PubMed

    Mascarenhas, Randy; MacDonald, Peter B

    2008-01-01

    Biological tissue autograft reconstruction using the patellar tendon or quadrupled semitendinosus/gracilis tendons has become the most popular procedure in surgical treatment of a ruptured ACL. This article provides a review of the history of the use of prosthetics with respect to ACL reconstruction grafts including Carbon Fibre, Gore-Tex and Dacron prosthetics as well as the Leeds-Keio Artificial Ligament and the Kennedy Ligament Augmentation Device (LAD). Emphasis is placed on the Ligament Advanced Reinforcement System (LARS) as preliminary investigations of its use have been encouraging. Significant progress has been made recently with respect to the understanding of ACL anatomy, composition, biomechanics, and healing processes, leading to innovative techniques using approaches based in tissue engineering principles and computer - assisted surgery. While research into improved ACL treatment options continues, the synthesis of recent advancements provides a new optimism towards the regeneration of an ACL mirroring its original stability, function, and longevity.

  11. A Comparison of Affect Ratings Obtained with Ecological Momentary Assessment and the Day Reconstruction Method

    ERIC Educational Resources Information Center

    Dockray, Samantha; Grant, Nina; Stone, Arthur A.; Kahneman, Daniel; Wardle, Jane; Steptoe, Andrew

    2010-01-01

    Measurement of affective states in everyday life is of fundamental importance in many types of quality of life, health, and psychological research. Ecological momentary assessment (EMA) is the recognized method of choice, but the respondent burden can be high. The day reconstruction method (DRM) was developed by Kahneman and colleagues ("Science,"…

  12. Phase microscopy using light-field reconstruction method for cell observation.

    PubMed

    Xiu, Peng; Zhou, Xin; Kuang, Cuifang; Xu, Yingke; Liu, Xu

    2015-08-01

    The refractive index (RI) distribution can serve as a natural label for undyed cell imaging. However, the majority of images obtained through quantitative phase microscopy is integrated along the illumination angle and cannot reflect additional information about the refractive map on a certain plane. Herein, a light-field reconstruction method to image the RI map within a depth of 0.2 μm is proposed. It records quantitative phase-delay images using a four-step phase shifting method in different directions and then reconstructs a similar scattered light field for the refractive sample on the focus plane. It can image the RI of samples, transparent cell samples in particular, in a manner similar to the observation of scattering characteristics. The light-field reconstruction method is therefore a powerful tool for use in cytobiology studies.

  13. Method and apparatus for reconstructing in-cylinder pressure and correcting for signal decay

    SciTech Connect

    Huang, Jian

    2013-03-12

    A method comprises steps for reconstructing in-cylinder pressure data from a vibration signal collected from a vibration sensor mounted on an engine component where it can generate a signal with a high signal-to-noise ratio, and correcting the vibration signal for errors introduced by vibration signal charge decay and sensor sensitivity. The correction factors are determined as a function of estimated motoring pressure and the measured vibration signal itself with each of these being associated with the same engine cycle. Accordingly, the method corrects for charge decay and changes in sensor sensitivity responsive to different engine conditions to allow greater accuracy in the reconstructed in-cylinder pressure data. An apparatus is also disclosed for practicing the disclosed method, comprising a vibration sensor, a data acquisition unit for receiving the vibration signal, a computer processing unit for processing the acquired signal and a controller for controlling the engine operation based on the reconstructed in-cylinder pressure.

  14. Correlation between the result from arthroscopic reconstruction of the anterior cruciate ligament of the knee and the return to sports activity☆

    PubMed Central

    Almeida, Alexandre; Valin, Márcio Rangel; Ferreira, Ramon; de Almeida, Nayvaldo Couto; Agostini, Ana Paula

    2014-01-01

    Objective To evaluate the return to pre-injury sports activity in a group of patients who underwent anterior cruciate ligament (ACL) reconstruction, in relation to age, sex, body mass index (BMI) and associations with upper-limb fractures. Methods A group of 265 patients who underwent ACL reconstruction using an ipsilateral graft from the thigh flexor tendons, between July 2000 and November 2007, was analyzed. Results A total of 176 patients was evaluated after a mean period of 34.95 ± 18.8 months (median: 31 months) (interquartile range: 20–48 months). The minimum evaluation period was 12 months and the maximum was 87 months. The number of patients who returned to their sports activity prior to tearing the ACL was 121/176 (68.8%). Patients under 30 years of age more frequently returned to sports activity and this was considered significant: p = 0.016; odds ratio, OR = 0.44 (95% confidence interval, CI: 0.22–0.86). Returning to previous sports activity more frequently was not considered significant for male sex (p = 0.273), individuals with BMI < 25 (p = 0.280) or patients with an ACL injury unrelated to an initial traumatic episode with upper-limb fracturing (p = 0.353). Conclusions The rate of return to the sports activity prior to ACL injury was 68.8%. It was found that patients under the age of 30 years had a significantly greater rate of return to sports activity after the surgery. In relation to sex, BMI and association with an initial traumatic episode of upper-limb fracturing, there was no statistical difference in the return to sports activity. PMID:26229807

  15. Practical methods for automated reconstruction and characterization of particles in digital in-line holograms

    NASA Astrophysics Data System (ADS)

    Fugal, Jacob P.; Schulz, Timothy J.; Shaw, Raymond A.

    2009-07-01

    Hologram reconstruction algorithms often undersample the phase in propagation kernels for typical parameters of holographic optical setups. Given in this paper is an algorithm that addresses this phase undersampling in reconstructing digital in-line holograms of particles for these typical parameters. This algorithm has a lateral sample spacing constant in reconstruction distance, has a diffraction limited resolution, and can be implemented with computational speeds comparable to the fastest of other reconstruction algorithms. This algorithm is shown to be accurate by testing with analytical solutions to the Huygens-Fresnel propagation integral. A low-pass filter can be applied to enforce a uniform minimum particle size detection limit throughout a sample volume, allowing this method to be useful in measuring particle size distributions and number densities. Tens of thousands of holograms of cloud ice particles are digitally reconstructed using the algorithm discussed. Positions of ice particles in the size range of 20 µm-1.5 mm are obtained using an algorithm that accurately finds the position of large and small particles along the optical axis. The digital reconstruction and particle characterization algorithms are implemented in an automated fashion with no user intervention on a computer cluster. Strategies for efficient algorithm implementation on a computer cluster are discussed.

  16. Neuromuscular Fatigue Alters Postural Control and Sagittal Plane Hip Biomechanics in Active Females With Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Frank, Barnett S.; Gilsdorf, Christine M.; Goerger, Benjamin M.; Prentice, William E.; Padua, Darin A.

    2014-01-01

    Background: Females with history of anterior cruciate ligament (ACL) injury and subsequent ligament reconstruction are at high risk for future ACL injury. Fatigue may influence the increased risk of future injury in females by altering lower extremity biomechanics and postural control. Hypothesis: Fatigue will promote lower extremity biomechanics and postural control deficits associated with ACL injury. Study Design: Descriptive laboratory study. Methods: Fourteen physically active females with ACL reconstruction (mean age, 19.64 ± 1.5 years; mean height, 163.52 ± 6.18 cm; mean mass, 62.6 ± 13.97 kg) volunteered for this study. Postural control and lower extremity biomechanics were assessed in the surgical limb during single-leg balance and jump-landing tasks before and after a fatigue protocol. Main outcome measures were 3-dimensional hip and knee joint angles at initial contact, peak angles, joint angular displacements and peak net joint moments, anterior tibial shear force, and vertical ground reaction force during the first 50% of the loading phase of the jump-landing task. During the single-leg stance task, the main outcome measure was center of pressure sway speed. Results: Initial contact hip flexion angle decreased (t = −2.82, P = 0.01; prefatigue, 40.98° ± 9.79°; postfatigue, 36.75° ± 8.61°) from pre- to postfatigue. Hip flexion displacement (t = 2.23, P = 0.04; prefatigue, 45.19° ± 14.1°; postfatigue, 47.48° ± 14.21°) and center of pressure sway speed (t = 3.95, P < 0.05; prefatigue, 5.18 ± 0.96 cm/s; postfatigue, 6.20 ± 1.72 cm/s) increased from pre- to postfatigue. There was a trending increase in hip flexion moment (t = 2.14, P = 0.05; prefatigue, 1.66 ± 0.68 Nm/kg/m; postfatigue, 1.91 ± 0.62 Nm/kg/m) from pre- to postfatigue. Conclusion: Fatigue may induce lower extremity biomechanics and postural control deficits that may be associated with ACL injury in physically active females with ACL reconstruction. Clinical Relevance

  17. Environment-based pin-power reconstruction method for homogeneous core calculations

    SciTech Connect

    Leroyer, H.; Brosselard, C.; Girardi, E.

    2012-07-01

    Core calculation schemes are usually based on a classical two-step approach associated with assembly and core calculations. During the first step, infinite lattice assemblies calculations relying on a fundamental mode approach are used to generate cross-sections libraries for PWRs core calculations. This fundamental mode hypothesis may be questioned when dealing with loading patterns involving several types of assemblies (UOX, MOX), burnable poisons, control rods and burn-up gradients. This paper proposes a calculation method able to take into account the heterogeneous environment of the assemblies when using homogeneous core calculations and an appropriate pin-power reconstruction. This methodology is applied to MOX assemblies, computed within an environment of UOX assemblies. The new environment-based pin-power reconstruction is then used on various clusters of 3x3 assemblies showing burn-up gradients and UOX/MOX interfaces, and compared to reference calculations performed with APOLLO-2. The results show that UOX/MOX interfaces are much better calculated with the environment-based calculation scheme when compared to the usual pin-power reconstruction method. The power peak is always better located and calculated with the environment-based pin-power reconstruction method on every cluster configuration studied. This study shows that taking into account the environment in transport calculations can significantly improve the pin-power reconstruction so far as it is consistent with the core loading pattern. (authors)

  18. Comparison of inverse methods for reconstructing the release history of a groundwater contamination source

    NASA Astrophysics Data System (ADS)

    Neupauer, Roseanna M.; Borchers, Brian; Wilson, John L.

    2000-09-01

    Inverse methods can be used to reconstruct the release history of a known source of groundwater contamination from concentration data describing the present-day spatial distribution of the contaminant plume. Using hypothetical release history functions and contaminant plumes, we evaluate the relative effectiveness of two proposed inverse methods, Tikhonov regularization (TR) and minimum relative entropy (MRE) inversion, in reconstructing the release history of a conservative contaminant in a one-dimensional domain [Skaggs and Kabala, 1994; Woodbury and Ulrych, 1996]. We also address issues of reproducibility of the solution and the appropriateness of models for simulating random measurement error. The results show that if error-free plume concentration data are available, both methods perform well in reconstructing a smooth source history function. With error-free data the MRE method is more robust than TR in reconstructing a nonsmooth source history function; however, the TR method is more robust if the data contain measurement error. Two error models were evaluated in this study, and we found that the particular error model does not affect the reliability of the solutions. The results for the TR method have somewhat greater reproducibility because, in some cases, its input parameters are less subjective than those of the MRE method; however, the MRE solution can identify regions where the data give little or no information about the source history function, while the TR solution cannot.

  19. An extended stochastic reconstruction method for catalyst layers in proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Kang, Jinfen; Moriyama, Koji; Kim, Seung Hyun

    2016-09-01

    This paper presents an extended, stochastic reconstruction method for catalyst layers (CLs) of Proton Exchange Membrane Fuel Cells (PEMFCs). The focus is placed on the reconstruction of customized, low platinum (Pt) loading CLs where the microstructure of CLs can substantially influence the performance. The sphere-based simulated annealing (SSA) method is extended to generate the CL microstructures with specified and controllable structural properties for agglomerates, ionomer, and Pt catalysts. In the present method, the agglomerate structures are controlled by employing a trial two-point correlation function used in the simulated annealing process. An off-set method is proposed to generate more realistic ionomer structures. The variations of ionomer structures at different humidity conditions are considered to mimic the swelling effects. A method to control Pt loading, distribution, and utilization is presented. The extension of the method to consider heterogeneity in structural properties, which can be found in manufactured CL samples, is presented. Various reconstructed CLs are generated to demonstrate the capability of the proposed method. Proton transport properties of the reconstructed CLs are calculated and validated with experimental data.

  20. Image reconstruction technique of electrical capacitance tomography for low-contrast dielectrics using Calderon's method

    NASA Astrophysics Data System (ADS)

    Cao, Zhang; Xu, Lijun; Wang, Huaxiang

    2009-10-01

    Calderon's method was introduced to electrical capacitance tomography in this paper. It is a direct algorithm of the image reconstruction for low-contrast dielectrics, as no matrix inversion or iterative process is needed. It was implemented through numerical integration. Since the Gauss-Legendre quadrature was applied and can be predetermined, the image reconstruction process was fast and resulted in images of high quality. Simulations were carried out to study the effect of different dielectric contrasts and different electrode numbers. Both simulated and experimental results validated the feasibility and effectiveness of Calderon's method in electrical capacitance tomography for low-contrast dielectrics.

  1. A new 3D reconstruction method of small solar system bodies

    NASA Astrophysics Data System (ADS)

    Capanna, C.; Jorda, L.; Lamy, P.; Gesquiere, G.

    2011-10-01

    The 3D reconstruction of small solar system bodies consitutes an essential step toward understanding and interpreting their physical and geological properties. We propose a new reconstruction method by photoclinometry based on the minimization of the chisquare difference between observed and synthetic images by deformation of a 3D triangular mesh. This method has been tested on images of the two asteroids (2867) Steins and (21) Lutetia observed during ESA's ROSETTA mission, and it will be applied to elaborate digital terrain models from images of the asteroid (4) Vesta, the target of NASA's DAWN spacecraft.

  2. Unhappy triad in limb reconstruction: Management by Ilizarov method

    PubMed Central

    El-Alfy, Barakat Sayed

    2017-01-01

    AIM To evaluate the results of the Ilizarov method in management of cases with bone loss, soft tissue loss and infection. METHODS Twenty eight patients with severe leg trauma complicated by bone loss, soft tissue loss and infection were managed by distraction osteogenesis in our institution. After radical debridement of all the infected and dead tissues the Ilizarov frame was applied, corticotomy was done and bone transport started. The wounds were left open to drain. Partial limb shortening was done in seven cases to reduce the size of both the skeletal and soft tissue defects. The average follow up period was 39 mo (range 27-56 mo). RESULTS The infection was eradicated in all cases. All the soft tissue defects healed during bone transport and plastic surgery was only required in 2 cases. Skeletal defects were treated in all cases. All patients required another surgery at the docking site to fashion the soft tissue and to cover the bone ends. The external fixation time ranged from 9 to 17 mo with an average of 13 mo. The complications included pin tract infection in 16 cases, wire breakage in 2 cases, unstable scar in 4 cases and chronic edema in 3 cases. According to the association for study and application of methods of Ilizarov score the bone results were excellent in 10, good in 16 and fair in 2 cases while the functional results were excellent in 8, good in 17 and fair in 3 cases. CONCLUSION Distraction osteogenesis is a good method that can treat the three problems of this triad simultaneously. PMID:28144578

  3. A comparative study of limited-angle cone-beam reconstruction methods for breast tomosynthesis

    PubMed Central

    Zhang, Yiheng; Chan, Heang-Ping; Sahiner, Berkman; Wei, Jun; Goodsitt, Mitchell M.; Hadjiiski, Lubomir M.; Ge, Jun; Zhou, Chuan

    2009-01-01

    Digital tomosynthesis mammography (DTM) is a promising new modality for breast cancer detection. In DTM, projection-view images are acquired at a limited number of angles over a limited angular range and the imaged volume is reconstructed from the two-dimensional projections, thus providing three-dimensional structural information of the breast tissue. In this work, we investigated three representative reconstruction methods for this limited-angle cone-beam tomographic problem, including the backprojection (BP) method, the simultaneous algebraic reconstruction technique (SART) and the maximum likelihood method with the convex algorithm (ML-convex). The SART and ML-convex methods were both initialized with BP results to achieve efficient reconstruction. A second generation GE prototype tomosynthesis mammography system with a stationary digital detector was used for image acquisition. Projection-view images were acquired from 21 angles in 3° increments over a ±30° angular range. We used an American College of Radiology phantom and designed three additional phantoms to evaluate the image quality and reconstruction artifacts. In addition to visual comparison of the reconstructed images of different phantom sets, we employed the contrast-to-noise ratio (CNR), a line profile of features, an artifact spread function (ASF), a relative noise power spectrum (NPS), and a line object spread function (LOSF) to quantitatively evaluate the reconstruction results. It was found that for the phantoms with homogeneous background, the BP method resulted in less noisy tomosynthesized images and higher CNR values for masses than the SART and ML-convex methods. However, the two iterative methods provided greater contrast enhancement for both masses and calcification, sharper LOSF, and reduced inter-plane blurring and artifacts with better ASF behaviors for masses. For a contrast-detail phantom with heterogeneous tissue-mimicking background, the BP method had strong blurring artifacts

  4. A pair-matched comparison of return to pivoting sports at 1 year in ACL-injured patients after a nonoperative versus operative treatment course

    PubMed Central

    Grindem, Hege; Eitzen, Ingrid; Moksnes, Håvard; Snyder-Mackler, Lynn; Risberg, May Arna

    2013-01-01

    Background The wish to return to level I pivoting sports is a major indication of ACL-reconstruction. Patients usually return to pivoting sports between 6 months and 1 year postoperatively, but no matched study has so far examined 1-year return to sport rates in nonoperatively and operatively treated ACL-injured patients. Hypothesis ACL-injured patients following a nonoperative treatment course, including recommendation of activity modification, will have lower return to pivoting sport rates than operatively treated patients 1 year after baseline testing/surgery, when matched by preinjury sports activity, age and sex. Study Design Pair-matched cohort study Methods Sixty-nine nonoperatively treated ACL-injured patients were pair-matched with 69 operatively treated patients (n=138), based on specific preinjury sport, age and sex. Nonoperatively treated patients were recommended not to return to level I sports. Patients were defined as nonoperatively or operatively treated according to their status at follow-up. The baseline and follow-up testing included registration of sports participation, KT-1000 measurements, 4 hop tests, and patient-reported outcome measures. McNemar’s test and paired t-tests or Wilcoxon’s test were used to compare outcomes of nonoperatively and operatively treated patients. Results No significant baseline differences were found. At 12.9±1.2 months (mean ± standard deviation) after baseline testing (nonoperative) and 12.7±1.2 months after surgery (operative), there was no significant difference in overall return to sport rates (nonoperative: 68.1 %, operative: 68.1 %, p=1.000), or in return to level I sport rates (nonoperative: 54.8 %, operative: 61.9 %, p=0.664). Nonoperatively treated patients who participated in level I sports prior to injury had a significantly lower return to sport rate (54.8 %) than nonoperatively treated patients who participated in level II sports (88.9 %, p=0.003). The nonoperatively treated patients had

  5. Combined Helmholtz equation-least squares method for reconstructing acoustic radiation from arbitrarily shaped objects.

    PubMed

    Wu, Sean F; Zhao, Xiang

    2002-07-01

    A combined Helmholtz equation-least squares (CHELS) method is developed for reconstructing acoustic radiation from an arbitrary object. This method combines the advantages of both the HELS method and the Helmholtz integral theory based near-field acoustic holography (NAH). As such it allows for reconstruction of the acoustic field radiated from an arbitrary object with relatively few measurements, thus significantly enhancing the reconstruction efficiency. The first step in the CHELS method is to establish the HELS formulations based on a finite number of acoustic pressure measurements taken on or beyond a hypothetical spherical surface that encloses the object under consideration. Next enough field acoustic pressures are generated using the HELS formulations and taken as the input to the Helmholtz integral formulations implemented through the boundary element method (BEM). The acoustic pressure and normal component of the velocity at the discretized nodes on the surface are then determined by solving two matrix equations using singular value decomposition (SVD) and regularization techniques. Also presented are in-depth analyses of the advantages and limitations of the CHELS method. Examples of reconstructing acoustic radiation from separable and nonseparable surfaces are demonstrated.

  6. Combined Helmholtz equation-least squares method for reconstructing acoustic radiation from arbitrarily shaped objects

    NASA Astrophysics Data System (ADS)

    Wu, Sean F.; Zhao, Xiang

    2002-07-01

    A combined Helmholtz equation-least squares (CHELS) method is developed for reconstructing acoustic radiation from an arbitrary object. This method combines the advantages of both the HELS method and the Helmholtz integral theory based near-field acoustic holography (NAH). As such it allows for reconstruction of the acoustic field radiated from an arbitrary object with relatively few measurements, thus significantly enhancing the reconstruction efficiency. The first step in the CHELS method is to establish the HELS formulations based on a finite number of acoustic pressure measurements taken on or beyond a hypothetical spherical surface that encloses the object under consideration. Next enough field acoustic pressures are generated using the HELS formulations and taken as the input to the Helmholtz integral formulations implemented through the boundary element method (BEM). The acoustic pressure and normal component of the velocity at the discretized nodes on the surface are then determined by solving two matrix equations using singular value decomposition (SVD) and regularization techniques. Also presented are in-depth analyses of the advantages and limitations of the CHELS method. Examples of reconstructing acoustic radiation from separable and nonseparable surfaces are demonstrated. copyright 2002 Acoustical Society of America.

  7. Reconstruction from Uniformly Attenuated SPECT Projection Data Using the DBH Method

    SciTech Connect

    Huang, Qiu; You, Jiangsheng; Zeng, Gengsheng L.; Gullberg, Grant T.

    2008-03-20

    An algorithm was developed for the two-dimensional (2D) reconstruction of truncated and non-truncated uniformly attenuated data acquired from single photon emission computed tomography (SPECT). The algorithm is able to reconstruct data from half-scan (180o) and short-scan (180?+fan angle) acquisitions for parallel- and fan-beam geometries, respectively, as well as data from full-scan (360o) acquisitions. The algorithm is a derivative, backprojection, and Hilbert transform (DBH) method, which involves the backprojection of differentiated projection data followed by an inversion of the finite weighted Hilbert transform. The kernel of the inverse weighted Hilbert transform is solved numerically using matrix inversion. Numerical simulations confirm that the DBH method provides accurate reconstructions from half-scan and short-scan data, even when there is truncation. However, as the attenuation increases, finer data sampling is required.

  8. Application of information theory methods to food web reconstruction

    USGS Publications Warehouse

    Moniz, L.J.; Cooch, E.G.; Ellner, S.P.; Nichols, J.D.; Nichols, J.M.

    2007-01-01

    In this paper we use information theory techniques on time series of abundances to determine the topology of a food web. At the outset, the food web participants (two consumers, two resources) are known; in addition we know that each consumer prefers one of the resources over the other. However, we do not know which consumer prefers which resource, and if this preference is absolute (i.e., whether or not the consumer will consume the non-preferred resource). Although the consumers and resources are identified at the beginning of the experiment, we also provide evidence that the consumers are not resources for each other, and the resources do not consume each other. We do show that there is significant mutual information between resources; the model is seasonally forced and some shared information between resources is expected. Similarly, because the model is seasonally forced, we expect shared information between consumers as they respond to the forcing of the resources. The model that we consider does include noise, and in an effort to demonstrate that these methods may be of some use in other than model data, we show the efficacy of our methods with decreasing time series size; in this particular case we obtain reasonably clear results with a time series length of 400 points. This approaches ecological time series lengths from real systems.

  9. Tunnel widening prevention with the allo-Achilles tendon graft in anterior cruciate ligament reconstruction: Surgical tips and short term followup

    PubMed Central

    Suh, Dong Won; Han, Seung Beom; Yeo, Woo Jin; Lee, Won Hee; Kwon, Jae Ho; Kyung, Bong Soo

    2017-01-01

    Background: Tunnel widening (TW) after anterior cruciate ligament (ACL) reconstruction can be a serious complication, and there is controversy over how to prevent it. This study aimed to suggest surgical approaches to prevent TW using an allo-Achilles tendon graft, and then to evaluate TW after these surgical tips were applied. Materials and Methods: Sixty two patients underwent ACL reconstruction with an allo-Achilles tendon graft. Four surgical approaches were used: Making a tibial tunnel by bone impaction, intraarticular reamer application, bone portion application for the femoral tunnel, and an additional bone plug application for the tibial tunnel. After more than 1-year, followup radiographs including anteroposterior and lateral views were taken in 29 patients encompassing thirty knees. The diameter of the tunnels at postoperation day 1 (POD1) and at followup was measured and compared. Results: In 18 knees (60%), there were no visible femoral tunnel margins on the radiographs at POD1 or followup. In the other 12 cases, which had visible femoral tunnel margins on followup radiographs, the mean femoral tunnel diameter was 8.6 mm. In the tibial tunnel, the mean diameters did not increase on all three levels (proximal, middle, and distal), and there was no statistically significant difference between the diameters at POD1 and followup. Conclusion: The suggested tips for surgery involving an allo-Achilles tendon graft can effectively prevent TW after ACL reconstruction according to this case series. These surgical tips can prevent TW.

  10. 3D reconstruction method from biplanar radiography using non-stereocorresponding points and elastic deformable meshes.

    PubMed

    Mitton, D; Landry, C; Véron, S; Skalli, W; Lavaste, F; De Guise, J A

    2000-03-01

    Standard 3D reconstruction of bones using stereoradiography is limited by the number of anatomical landmarks visible in more than one projection. The proposed technique enables the 3D reconstruction of additional landmarks that can be identified in only one of the radiographs. The principle of this method is the deformation of an elastic object that respects stereocorresponding and non-stereocorresponding observations available in different projections. This technique is based on the principle that any non-stereocorresponding point belongs to a line joining the X-ray source and the projection of the point in one view. The aim is to determine the 3D position of these points on their line of projection when submitted to geometrical and topological constraints. This technique is used to obtain the 3D geometry of 18 cadaveric upper cervical vertebrae. The reconstructed geometry obtained is compared with direct measurements using a magnetic digitiser. The order of precision determined with the point-to-surface distance between the reconstruction obtained with that technique and reference measurements is about 1 mm, depending on the vertebrae studied. Comparison results indicate that the obtained reconstruction is close to the actual vertebral geometry. This method can therefore be proposed to obtain the 3D geometry of vertebrae.

  11. Virtual biomechanics: a new method for online reconstruction of force from EMG recordings.

    PubMed

    de Rugy, Aymar; Loeb, Gerald E; Carroll, Timothy J

    2012-12-01

    Current methods to reconstruct muscle contributions to joint torque usually combine electromyograms (EMGs) with cadaver-based estimates of biomechanics, but both are imperfect representations of reality. Here, we describe a new method that enables online force reconstruction in which we optimize a "virtual" representation of muscle biomechanics. We first obtain tuning curves for the five major wrist muscles from the mean rectified EMG during the hold phase of an isometric aiming task when a cursor is driven by actual force recordings. We then apply a custom, gradient-descent algorithm to determine the set of "virtual pulling vectors" that best reach the target forces when combined with the observed muscle activity. When these pulling vectors are multiplied by the rectified and low-pass-filtered (1.3 Hz) EMG of the five muscles online, the reconstructed force provides a close spatiotemporal match to the true force exerted at the wrist. In three separate experiments, we demonstrate that the technique works equally well for surface and fine-wire recordings and is sensitive to biomechanical changes elicited by a modification of the forearm posture. In all conditions tested, muscle tuning curves obtained when the task was performed with feedback of reconstructed force were similar to those obtained when the task was performed with real force feedback. This online force reconstruction technique provides new avenues to study the relationship between neural control and limb biomechanics since the "virtual biomechanics" can be systematically altered at will.

  12. Comparison of the calorimetric and kinematic methods of neutrino energy reconstruction in disappearance experiments

    DOE PAGES

    Ankowski, Artur M.; Benhar, Omar; Coloma, Pilar; ...

    2015-10-22

    To be able to achieve their physics goals, future neutrino-oscillation experiments will need to reconstruct the neutrino energy with very high accuracy. In this work, we analyze how the energy reconstruction may be affected by realistic detection capabilities, such as energy resolutions, efficiencies, and thresholds. This allows us to estimate how well the detector performance needs to be determined a priori in order to avoid a sizable bias in the measurement of the relevant oscillation parameters. We compare the kinematic and calorimetric methods of energy reconstruction in the context of two νμ → νμ disappearance experiments operating in different energymore » regimes. For the calorimetric reconstruction method, we find that the detector performance has to be estimated with an O(10%) accuracy to avoid a significant bias in the extracted oscillation parameters. Thus, in the case of kinematic energy reconstruction, we observe that the results exhibit less sensitivity to an overestimation of the detector capabilities.« less

  13. Comparison of the calorimetric and kinematic methods of neutrino energy reconstruction in disappearance experiments

    SciTech Connect

    Ankowski, Artur M.; Benhar, Omar; Coloma, Pilar; Huber, Patrick; Jen, Chun -Min; Mariani, Camillo; Meloni, Davide; Vagnoni, Erica

    2015-10-22

    To be able to achieve their physics goals, future neutrino-oscillation experiments will need to reconstruct the neutrino energy with very high accuracy. In this work, we analyze how the energy reconstruction may be affected by realistic detection capabilities, such as energy resolutions, efficiencies, and thresholds. This allows us to estimate how well the detector performance needs to be determined a priori in order to avoid a sizable bias in the measurement of the relevant oscillation parameters. We compare the kinematic and calorimetric methods of energy reconstruction in the context of two νμ → νμ disappearance experiments operating in different energy regimes. For the calorimetric reconstruction method, we find that the detector performance has to be estimated with an O(10%) accuracy to avoid a significant bias in the extracted oscillation parameters. Thus, in the case of kinematic energy reconstruction, we observe that the results exhibit less sensitivity to an overestimation of the detector capabilities.

  14. Optical tomography reconstruction algorithm with the finite element method: An optimal approach with regularization tools

    SciTech Connect

    Balima, O.; Favennec, Y.; Rousse, D.

    2013-10-15

    Highlights: •New strategies to improve the accuracy of the reconstruction through mesh and finite element parameterization. •Use of gradient filtering through an alternative inner product within the adjoint method. •An integral form of the cost function is used to make the reconstruction compatible with all finite element formulations, continuous and discontinuous. •Gradient-based algorithm with the adjoint method is used for the reconstruction. -- Abstract: Optical tomography is mathematically treated as a non-linear inverse problem where the optical properties of the probed medium are recovered through the minimization of the errors between the experimental measurements and their predictions with a numerical model at the locations of the detectors. According to the ill-posed behavior of the inverse problem, some regularization tools must be performed and the Tikhonov penalization type is the most commonly used in optical tomography applications. This paper introduces an optimized approach for optical tomography reconstruction with the finite element method. An integral form of the cost function is used to take into account the surfaces of the detectors and make the reconstruction compatible with all finite element formulations, continuous and discontinuous. Through a gradient-based algorithm where the adjoint method is used to compute the gradient of the cost function, an alternative inner product is employed for preconditioning the reconstruction algorithm. Moreover, appropriate re-parameterization of the optical properties is performed. These regularization strategies are compared with the classical Tikhonov penalization one. It is shown that both the re-parameterization and the use of the Sobolev cost function gradient are efficient for solving such an ill-posed inverse problem.

  15. A regional method for craniofacial reconstruction based on coordinate adjustments and a new fusion strategy.

    PubMed

    Deng, Qingqiong; Zhou, Mingquan; Wu, Zhongke; Shui, Wuyang; Ji, Yuan; Wang, Xingce; Liu, Ching Yiu Jessica; Huang, Youliang; Jiang, Haiyan

    2016-02-01

    Craniofacial reconstruction recreates a facial outlook from the cranium based on the relationship between the face and the skull to assist identification. But craniofacial structures are very complex, and this relationship is not the same in different craniofacial regions. Several regional methods have recently been proposed, these methods segmented the face and skull into regions, and the relationship of each region is then learned independently, after that, facial regions for a given skull are estimated and finally glued together to generate a face. Most of these regional methods use vertex coordinates to represent the regions, and they define a uniform coordinate system for all of the regions. Consequently, the inconsistence in the positions of regions between different individuals is not eliminated before learning the relationships between the face and skull regions, and this reduces the accuracy of the craniofacial reconstruction. In order to solve this problem, an improved regional method is proposed in this paper involving two types of coordinate adjustments. One is the global coordinate adjustment performed on the skulls and faces with the purpose to eliminate the inconsistence of position and pose of the heads; the other is the local coordinate adjustment performed on the skull and face regions with the purpose to eliminate the inconsistence of position of these regions. After these two coordinate adjustments, partial least squares regression (PLSR) is used to estimate the relationship between the face region and the skull region. In order to obtain a more accurate reconstruction, a new fusion strategy is also proposed in the paper to maintain the reconstructed feature regions when gluing the facial regions together. This is based on the observation that the feature regions usually have less reconstruction errors compared to rest of the face. The results demonstrate that the coordinate adjustments and the new fusion strategy can significantly improve the

  16. Analysis of dental root apical morphology: a new method for dietary reconstructions in primates.

    PubMed

    Hamon, NoÉmie; Emonet, Edouard-Georges; Chaimanee, Yaowalak; Guy, Franck; Tafforeau, Paul; Jaeger, Jean-Jacques

    2012-06-01

    The reconstruction of paleo-diets is an important task in the study of fossil primates. Previously, paleo-diet reconstructions were performed using different methods based on extant primate models. In particular, dental microwear or isotopic analyses provided accurate reconstructions for some fossil primates. However, there is sometimes difficult or impossible to apply these methods to fossil material. Therefore, the development of new, independent methods of diet reconstructions is crucial to improve our knowledge of primates paleobiology and paleoecology. This study aims to investigate the correlation between tooth root apical morphology and diet in primates, and its potential for paleo-diet reconstructions. Dental roots are composed of two portions: the eruptive portion with a smooth and regular surface, and the apical penetrative portion which displays an irregular and corrugated surface. Here, the angle formed by these two portions (aPE), and the ratio of penetrative portion over total root length (PPI), are calculated for each mandibular tooth root. A strong correlation between these two variables and the proportion of some food types (fruits, leaves, seeds, animal matter, and vertebrates) in diet is found, allowing the use of tooth root apical morphology as a tool for dietary reconstructions in primates. The method was then applied to the fossil hominoid Khoratpithecus piriyai, from the Late Miocene of Thailand. The paleo-diet deduced from aPE and PPI is dominated by fruits (>50%), associated with animal matter (1-25%). Leaves, vertebrates and most probably seeds were excluded from the diet of Khoratpithecus, which is consistent with previous studies.

  17. An improved schlieren method for measurement and automatic reconstruction of the far-field focal spot

    PubMed Central

    Wang, Zhengzhou; Hu, Bingliang; Yin, Qinye

    2017-01-01

    The schlieren method of measuring far-field focal spots offers many advantages at the Shenguang III laser facility such as low cost and automatic laser-path collimation. However, current methods of far-field focal spot measurement often suffer from low precision and efficiency when the final focal spot is merged manually, thereby reducing the accuracy of reconstruction. In this paper, we introduce an improved schlieren method to construct the high dynamic-range image of far-field focal spots and improve the reconstruction accuracy and efficiency. First, a detection method based on weak light beam sampling and magnification imaging was designed; images of the main and side lobes of the focused laser irradiance in the far field were obtained using two scientific CCD cameras. Second, using a self-correlation template matching algorithm, a circle the same size as the schlieren ball was dug from the main lobe cutting image and used to change the relative region of the main lobe cutting image within a 100×100 pixel region. The position that had the largest correlation coefficient between the side lobe cutting image and the main lobe cutting image when a circle was dug was identified as the best matching point. Finally, the least squares method was used to fit the center of the side lobe schlieren small ball, and the error was less than 1 pixel. The experimental results show that this method enables the accurate, high-dynamic-range measurement of a far-field focal spot and automatic image reconstruction. Because the best matching point is obtained through image processing rather than traditional reconstruction methods based on manual splicing, this method is less sensitive to the efficiency of focal-spot reconstruction and thus offers better experimental precision. PMID:28207758

  18. A comparative study of interface reconstruction methods for multi-material ALE simulations

    SciTech Connect

    Kucharik, Milan; Garimalla, Rao; Schofield, Samuel; Shashkov, Mikhail

    2009-01-01

    In this paper we compare the performance of different methods for reconstructing interfaces in multi-material compressible flow simulations. The methods compared are a material-order-dependent Volume-of-Fluid (VOF) method, a material-order-independent VOF method based on power diagram partitioning of cells and the Moment-of-Fluid method (MOF). We demonstrate that the MOF method provides the most accurate tracking of interfaces, followed by the VOF method with the right material ordering. The material-order-independent VOF method performs some-what worse than the above two while the solutions with VOF using the wrong material order are considerably worse.

  19. A comparative study of interface reconstruction methods for multi-material ALE simulations

    SciTech Connect

    Kucharik, Milan Garimella, Rao V. Schofield, Samuel P. Shashkov, Mikhail J.

    2010-04-01

    In this paper we compare the performance of different methods for reconstructing interfaces in multi-material compressible flow simulations. The methods compared are a material-order-dependent Volume-of-Fluid (VOF) method, a material-order-independent VOF method based on power diagram partitioning of cells and the Moment-of-Fluid method (MOF). We demonstrate that the MOF method provides the most accurate tracking of interfaces, followed by the VOF method with the right material ordering. The material-order-independent VOF method performs somewhat worse than the above two while the solutions with VOF using the wrong material order are considerably worse.

  20. A continuous surface reconstruction method on point cloud captured from a 3D surface photogrammetry system

    SciTech Connect

    Liu, Wenyang; Cheung, Yam; Sabouri, Pouya; Arai, Tatsuya J.; Sawant, Amit; Ruan, Dan

    2015-11-15

    Purpose: To accurately and efficiently reconstruct a continuous surface from noisy point clouds captured by a surface photogrammetry system (VisionRT). Methods: The authors have developed a level-set based surface reconstruction method on point clouds captured by a surface photogrammetry system (VisionRT). The proposed method reconstructs an implicit and continuous representation of the underlying patient surface by optimizing a regularized fitting energy, offering extra robustness to noise and missing measurements. By contrast to explicit/discrete meshing-type schemes, their continuous representation is particularly advantageous for subsequent surface registration and motion tracking by eliminating the need for maintaining explicit point correspondences as in discrete models. The authors solve the proposed method with an efficient narrowband evolving scheme. The authors evaluated the proposed method on both phantom and human subject data with two sets of complementary experiments. In the first set of experiment, the authors generated a series of surfaces each with different black patches placed on one chest phantom. The resulting VisionRT measurements from the patched area had different degree of noise and missing levels, since VisionRT has difficulties in detecting dark surfaces. The authors applied the proposed method to point clouds acquired under these different configurations, and quantitatively evaluated reconstructed surfaces by comparing against a high-quality reference surface with respect to root mean squared error (RMSE). In the second set of experiment, the authors applied their method to 100 clinical point clouds acquired from one human subject. In the absence of ground-truth, the authors qualitatively validated reconstructed surfaces by comparing the local geometry, specifically mean curvature distributions, against that of the surface extracted from a high-quality CT obtained from the same patient. Results: On phantom point clouds, their method

  1. A continuous surface reconstruction method on point cloud captured from a 3D surface photogrammetry system

    PubMed Central

    Liu, Wenyang; Cheung, Yam; Sabouri, Pouya; Arai, Tatsuya J.; Sawant, Amit; Ruan, Dan

    2015-01-01

    Purpose: To accurately and efficiently reconstruct a continuous surface from noisy point clouds captured by a surface photogrammetry system (VisionRT). Methods: The authors have developed a level-set based surface reconstruction method on point clouds captured by a surface photogrammetry system (VisionRT). The proposed method reconstructs an implicit and continuous representation of the underlying patient surface by optimizing a regularized fitting energy, offering extra robustness to noise and missing measurements. By contrast to explicit/discrete meshing-type schemes, their continuous representation is particularly advantageous for subsequent surface registration and motion tracking by eliminating the need for maintaining explicit point correspondences as in discrete models. The authors solve the proposed method with an efficient narrowband evolving scheme. The authors evaluated the proposed method on both phantom and human subject data with two sets of complementary experiments. In the first set of experiment, the authors generated a series of surfaces each with different black patches placed on one chest phantom. The resulting VisionRT measurements from the patched area had different degree of noise and missing levels, since VisionRT has difficulties in detecting dark surfaces. The authors applied the proposed method to point clouds acquired under these different configurations, and quantitatively evaluated reconstructed surfaces by comparing against a high-quality reference surface with respect to root mean squared error (RMSE). In the second set of experiment, the authors applied their method to 100 clinical point clouds acquired from one human subject. In the absence of ground-truth, the authors qualitatively validated reconstructed surfaces by comparing the local geometry, specifically mean curvature distributions, against that of the surface extracted from a high-quality CT obtained from the same patient. Results: On phantom point clouds, their method

  2. Pantograph: A template-based method for genome-scale metabolic model reconstruction.

    PubMed

    Loira, Nicolas; Zhukova, Anna; Sherman, David James

    2015-04-01

    Genome-scale metabolic models are a powerful tool to study the inner workings of biological systems and to guide applications. The advent of cheap sequencing has brought the opportunity to create metabolic maps of biotechnologically interesting organisms. While this drives the development of new methods and automatic tools, network reconstruction remains a time-consuming process where extensive manual curation is required. This curation introduces specific knowledge about the modeled organism, either explicitly in the form of molecular processes, or indirectly in the form of annotations of the model elements. Paradoxically, this knowledge is usually lost when reconstruction of a different organism is started. We introduce the Pantograph method for metabolic model reconstruction. This method combines a template reaction knowledge base, orthology mappings between two organisms, and experimental phenotypic evidence, to build a genome-scale metabolic model for a target organism. Our method infers implicit knowledge from annotations in the template, and rewrites these inferences to include them in the resulting model of the target organism. The generated model is well suited for manual curation. Scripts for evaluating the model with respect to experimental data are automatically generated, to aid curators in iterative improvement. We present an implementation of the Pantograph method, as a toolbox for genome-scale model reconstruction, curation and validation. This open source package can be obtained from: http://pathtastic.gforge.inria.fr.

  3. Spectrum reconstruction method based on the detector response model calibrated by x-ray fluorescence.

    PubMed

    Li, Ruizhe; Li, Liang; Chen, Zhiqiang

    2017-02-07

    Accurate estimation of distortion-free spectra is important but difficult in various applications, especially for spectral computed tomography. Two key problems must be solved to reconstruct the incident spectrum. One is the acquisition of the detector energy response. It can be calculated by Monte Carlo simulation, which requires detailed modeling of the detector system and a high computational power. It can also be acquired by establishing a parametric response model and be calibrated using monochromatic x-ray sources, such as synchrotron sources or radioactive isotopes. However, these monochromatic sources are difficult to obtain. Inspired by x-ray fluorescence (XRF) spectrum modeling, we propose a feasible method to obtain the detector energy response based on an optimized parametric model for CdZnTe or CdTe detectors. The other key problem is the reconstruction of the incident spectrum with the detector response. Directly obtaining an accurate solution from noisy data is difficult because the reconstruction problem is severely ill-posed. Different from the existing spectrum stripping method, a maximum likelihood-expectation maximization iterative algorithm is developed based on the Poisson noise model of the system. Simulation and experiment results show that our method is effective for spectrum reconstruction and markedly increases the accuracy of XRF spectra compared with the spectrum stripping method. The applicability of the proposed method is discussed, and promising results are presented.

  4. Spectrum reconstruction method based on the detector response model calibrated by x-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Li, Ruizhe; Li, Liang; Chen, Zhiqiang

    2017-02-01

    Accurate estimation of distortion-free spectra is important but difficult in various applications, especially for spectral computed tomography. Two key problems must be solved to reconstruct the incident spectrum. One is the acquisition of the detector energy response. It can be calculated by Monte Carlo simulation, which requires detailed modeling of the detector system and a high computational power. It can also be acquired by establishing a parametric response model and be calibrated using monochromatic x-ray sources, such as synchrotron sources or radioactive isotopes. However, these monochromatic sources are difficult to obtain. Inspired by x-ray fluorescence (XRF) spectrum modeling, we propose a feasible method to obtain the detector energy response based on an optimized parametric model for CdZnTe or CdTe detectors. The other key problem is the reconstruction of the incident spectrum with the detector response. Directly obtaining an accurate solution from noisy data is difficult because the reconstruction problem is severely ill-posed. Different from the existing spectrum stripping method, a maximum likelihood-expectation maximization iterative algorithm is developed based on the Poisson noise model of the system. Simulation and experiment results show that our method is effective for spectrum reconstruction and markedly increases the accuracy of XRF spectra compared with the spectrum stripping method. The applicability of the proposed method is discussed, and promising results are presented.

  5. Single-cell volume estimation by applying three-dimensional reconstruction methods

    NASA Astrophysics Data System (ADS)

    Khatibi, Siamak; Allansson, Louise; Gustavsson, Tomas; Blomstrand, Fredrik; Hansson, Elisabeth; Olsson, Torsten

    1999-05-01

    We have studied three-dimensional reconstruction methods to estimate the cell volume of astroglial cells in primary culture. The studies are based on fluorescence imaging and optical sectioning. An automated image-acquisition system was developed to collect two-dimensional microscopic images. Images were reconstructed by the Linear Maximum a Posteriori method and the non-linear Maximum Likelihood Expectation Maximization (ML-EM) method. In addition, because of the high computational demand of the ML-EM algorithm, we have developed a fast variant of this method. (1) Advanced image analysis techniques were applied for accurate and automated cell volume determination. (2) The sensitivity and accuracy of the reconstruction methods were evaluated by using fluorescent micro-beads with known diameter. The algorithms were applied to fura-2-labeled astroglial cells in primary culture exposed to hypo- or hyper-osmotic stress. The results showed that the ML-EM reconstructed images are adequate for the determination of volume changes in cells or parts thereof.

  6. Reconstruction of the sound field above a reflecting plane using the equivalent source method

    NASA Astrophysics Data System (ADS)

    Bi, Chuan-Xing; Jing, Wen-Qian; Zhang, Yong-Bin; Lin, Wang-Lin

    2017-01-01

    In practical situations, vibrating objects are usually located above a reflecting plane instead of exposing to a free field. The conventional nearfield acoustic holography (NAH) sometimes fails to identify sound sources under such situations. This paper develops two kinds of equivalent source method (ESM)-based half-space NAH to reconstruct the sound field above a reflecting plane. In the first kind of method, the half-space Green's function is introduced into the ESM-based NAH, and the sound field is reconstructed based on the condition that the surface impedance of the reflecting plane is known a prior. The second kind of method regards the reflections as being radiated by equivalent sources placed under the reflecting plane, and the sound field is reconstructed by matching the pressure on the hologram surface with the equivalent sources distributed within the vibrating object and those substituting for reflections. Thus, this kind of method is independent of the surface impedance of the reflecting plane. Numerical simulations and experiments demonstrate the feasibility of these two kinds of methods for reconstructing the sound field above a reflecting plane.

  7. Phase derivative method for reconstruction of slightly off-axis digital holograms.

    PubMed

    Guo, Cheng-Shan; Wang, Ben-Yi; Sha, Bei; Lu, Yu-Jie; Xu, Ming-Yuan

    2014-12-15

    A phase derivative (PD) method is proposed for reconstruction of off-axis holograms. In this method, a phase distribution of the tested object wave constrained within 0 to pi radian is firstly worked out by a simple analytical formula; then it is corrected to its right range from -pi to pi according to the sign characteristics of its first-order derivative. A theoretical analysis indicates that this PD method is particularly suitable for reconstruction of slightly off-axis holograms because it only requires the spatial frequency of the reference beam larger than spatial frequency of the tested object wave in principle. In addition, because the PD method belongs to a pure local method with no need of any integral operation or phase shifting algorithm in process of the phase retrieval, it could have some advantages in reducing computer load and memory requirements to the image processing system. Some experimental results are given to demonstrate the feasibility of the method.

  8. An Evaluation of Phylogenetic Methods for Reconstructing Transmitted HIV Variants using Longitudinal Clonal HIV Sequence Data

    PubMed Central

    McCloskey, Rosemary M.; Liang, Richard H.; Harrigan, P. Richard; Brumme, Zabrina L.

    2014-01-01

    ABSTRACT A population of human immunodeficiency virus (HIV) within a host often descends from a single transmitted/founder virus. The high mutation rate of HIV, coupled with long delays between infection and diagnosis, make isolating and characterizing this strain a challenge. In theory, ancestral reconstruction could be used to recover this strain from sequences sampled in chronic infection; however, the accuracy of phylogenetic techniques in this context is unknown. To evaluate the accuracy of these methods, we applied ancestral reconstruction to a large panel of published longitudinal clonal and/or single-genome-amplification HIV sequence data sets with at least one intrapatient sequence set sampled within 6 months of infection or seroconversion (n = 19,486 sequences, median [interquartile range] = 49 [20 to 86] sequences/set). The consensus of the earliest sequences was used as the best possible estimate of the transmitted/founder. These sequences were compared to ancestral reconstructions from sequences sampled at later time points using both phylogenetic and phylogeny-naive methods. Overall, phylogenetic methods conferred a 16% improvement in reproducing the consensus of early sequences, compared to phylogeny-naive methods. This relative advantage increased with intrapatient sequence diversity (P < 10−5) and the time elapsed between the earliest and subsequent samples (P < 10−5). However, neither approach performed well for reconstructing ancestral indel variation, especially within indel-rich regions of the HIV genome. Although further improvements are needed, our results indicate that phylogenetic methods for ancestral reconstruction significantly outperform phylogeny-naive alternatives, and we identify experimental conditions and study designs that can enhance accuracy of transmitted/founder virus reconstruction. IMPORTANCE When HIV is transmitted into a new host, most of the viruses fail to infect host cells. Consequently, an HIV infection tends to be

  9. Management of Acute Combined ACL-Medial and Posteromedial Instability of the Knee.

    PubMed

    Medvecky, Michael J; Tomaszewski, Paul

    2015-06-01

    Medial collateral ligament (MCL) injuries are the most common ligamentous injury of the knee. The extent of injury can range from a minor first-degree (1-degree) sprain to an extensive third-degree (3-degree) sprain that can propagate across the knee, rupturing one or both cruciate ligaments, and result in a knee subluxation or dislocation. A common pattern involves the combined anterior cruciate ligament (ACL) and MCL injury that is the focus of this chapter. The vast majority of these combined medial-sided injuries are treated nonoperatively with delayed reconstruction of the ACL injury in athletically active individuals. The MCL and associated medial structures are carefully assessed on physical examination, and classification of injury is based upon abnormal limits of joint motion. In vitro cadaveric biomechanical testing has given us a better understanding of ligament deficiency and altered joint motion. Consistency in terminology is necessary for proper classification of injury and reproducible categorization of injury patterns to be able to compare both nonoperative and operative treatment of various injury patterns.

  10. Reconstruction of nonstationary sound fields based on the time domain plane wave superposition method.

    PubMed

    Zhang, Xiao-Zheng; Thomas, Jean-Hugh; Bi, Chuan-Xing; Pascal, Jean-Claude

    2012-10-01

    A time-domain plane wave superposition method is proposed to reconstruct nonstationary sound fields. In this method, the sound field is expressed as a superposition of time convolutions between the estimated time-wavenumber spectrum of the sound pressure on a virtual source plane and the time-domain propagation kernel at each wavenumber. By discretizing the time convolutions directly, the reconstruction can be carried out iteratively in the time domain, thus providing the advantage of continuously reconstructing time-dependent pressure signals. In the reconstruction process, the Tikhonov regularization is introduced at each time step to obtain a relevant estimate of the time-wavenumber spectrum on the virtual source plane. Because the double infinite integral of the two-dimensional spatial Fourier transform is discretized directly in the wavenumber domain in the proposed method, it does not need to perform the two-dimensional spatial fast Fourier transform that is generally used in time domain holography and real-time near-field acoustic holography, and therefore it avoids some errors associated with the two-dimensional spatial fast Fourier transform in theory and makes possible to use an irregular microphone array. The feasibility of the proposed method is demonstrated by numerical simulations and an experiment with two speakers.

  11. Inverse Heat Conduction Methods in the CHAR Code for Aerothermal Flight Data Reconstruction

    NASA Technical Reports Server (NTRS)

    Oliver, A. Brandon; Amar, Adam J.

    2016-01-01

    Reconstruction of flight aerothermal environments often requires the solution of an inverse heat transfer problem, which is an ill-posed problem of determining boundary conditions from discrete measurements in the interior of the domain. This paper will present the algorithms implemented in the CHAR code for use in reconstruction of EFT-1 flight data and future testing activities. Implementation details will be discussed, and alternative hybrid-methods that are permitted by the implementation will be described. Results will be presented for a number of problems.

  12. Inverse Heat Conduction Methods in the CHAR Code for Aerothermal Flight Data Reconstruction

    NASA Technical Reports Server (NTRS)

    Oliver, A Brandon; Amar, Adam J.

    2016-01-01

    Reconstruction of flight aerothermal environments often requires the solution of an inverse heat transfer problem, which is an ill-posed problem of specifying boundary conditions from discrete measurements in the interior of the domain. This paper will present the algorithms implemented in the CHAR code for use in reconstruction of EFT-1 flight data and future testing activities. Implementation nuances will be discussed, and alternative hybrid-methods that are permitted by the implementation will be described. Results will be presented for a number of one-dimensional and multi-dimensional problems

  13. A novel method for event reconstruction in Liquid Argon Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Diwan, M.; Potekhin, M.; Viren, B.; Qian, X.; Zhang, C.

    2016-10-01

    Future experiments such as the Deep Underground Neutrino Experiment (DUNE) will use very large Liquid Argon Projection Chambers (LArTPC) containing tens of kilotons of cryogenic medium. To be able to utilize sensitive volume of that size, current design employs arrays of wire electrodes grouped in readout planes, arranged with a stereo angle. This leads to certain challenges for object reconstruction due to ambiguities inherent in such a scheme. We present a novel reconstruction method (named "Wirecell") inspired by principles used in tomography, which brings the LArTPC technology closer to its full potential.

  14. A simple method of aortic valve reconstruction with fixed pericardium in children

    PubMed Central

    Hosseinpour, Amir-Reza; González-Calle, Antonio; Adsuar-Gómez, Alejandro; Santos-deSoto, José

    2013-01-01

    Aortic valve reconstruction with fixed pericardium may occasionally be very useful when treating children with aortic valve disease. This is because diseased aortic valves in children are sometimes too dysmorphic for simple repair without the addition of material, their annulus may be too small for a prosthesis, and the Ross operation may be precluded due to other congenital anomalies such as pulmonary valvar or coronary malformations. Such reconstruction is usually technically demanding and requires much precision. We describe a simple alternative method, which we have carried out in 3 patients, aged 1 week, 3 years and 12 years, respectively, with good early results. PMID:23343835

  15. Comparisons between real and complex Gauss wavelet transform methods of three-dimensional shape reconstruction

    NASA Astrophysics Data System (ADS)

    Xu, Luopeng; Dan, Youquan; Wang, Qingyuan

    2015-10-01

    The continuous wavelet transform (CWT) introduces an expandable spatial and frequency window which can overcome the inferiority of localization characteristic in Fourier transform and windowed Fourier transform. The CWT method is widely applied in the non-stationary signal analysis field including optical 3D shape reconstruction with remarkable performance. In optical 3D surface measurement, the performance of CWT for optical fringe pattern phase reconstruction usually depends on the choice of wavelet function. A large kind of wavelet functions of CWT, such as Mexican Hat wavelet, Morlet wavelet, DOG wavelet, Gabor wavelet and so on, can be generated from Gauss wavelet function. However, so far, application of the Gauss wavelet transform (GWT) method (i.e. CWT with Gauss wavelet function) in optical profilometry is few reported. In this paper, the method using GWT for optical fringe pattern phase reconstruction is presented first and the comparisons between real and complex GWT methods are discussed in detail. The examples of numerical simulations are also given and analyzed. The results show that both the real GWT method along with a Hilbert transform and the complex GWT method can realize three-dimensional surface reconstruction; and the performance of reconstruction generally depends on the frequency domain appearance of Gauss wavelet functions. For the case of optical fringe pattern of large phase variation with position, the performance of real GWT is better than that of complex one due to complex Gauss series wavelets existing frequency sidelobes. Finally, the experiments are carried out and the experimental results agree well with our theoretical analysis.

  16. A Reconstructed Discontinuous Galerkin Method for the Euler Equations on Arbitrary Grids

    SciTech Connect

    Hong Luo; Luqing Luo; Robert Nourgaliev

    2012-11-01

    A reconstruction-based discontinuous Galerkin (RDG(P1P2)) method, a variant of P1P2 method, is presented for the solution of the compressible Euler equations on arbitrary grids. In this method, an in-cell reconstruction, designed to enhance the accuracy of the discontinuous Galerkin method, is used to obtain a quadratic polynomial solution (P2) from the underlying linear polynomial (P1) discontinuous Galerkin solution using a least-squares method. The stencils used in the reconstruction involve only the von Neumann neighborhood (face-neighboring cells) and are compact and consistent with the underlying DG method. The developed RDG method is used to compute a variety of flow problems on arbitrary meshes to demonstrate its accuracy, efficiency, robustness, and versatility. The numerical results indicate that this RDG(P1P2) method is third-order accurate, and outperforms the third-order DG method (DG(P2)) in terms of both computing costs and storage requirements.

  17. Performance study of Lagrangian methods: reconstruction of large scale peculiar velocities and baryonic acoustic oscillations

    NASA Astrophysics Data System (ADS)

    Keselman, J. A.; Nusser, A.

    2017-01-01

    NoAM for "No Action Method" is a framework for reconstructing the past orbits of observed tracers of the large scale mass density field. It seeks exact solutions of the equations of motion (EoM), satisfying initial homogeneity and the final observed particle (tracer) positions. The solutions are found iteratively reaching a specified tolerance defined as the RMS of the distance between reconstructed and observed positions. Starting from a guess for the initial conditions, NoAM advances particles using standard N-body techniques for solving the EoM. Alternatively, the EoM can be replaced by any approximation such as Zel'dovich and second order perturbation theory (2LPT). NoAM is suitable for billions of particles and can easily handle non-regular volumes, redshift space, and other constraints. We implement NoAM to systematically compare Zel'dovich, 2LPT, and N-body dynamics over diverse configurations ranging from idealized high-res periodic simulation box to realistic galaxy mocks. Our findings are (i) Non-linear reconstructions with Zel'dovich, 2LPT, and full dynamics perform better than linear theory only for idealized catalogs in real space. For realistic catalogs, linear theory is the optimal choice for reconstructing velocity fields smoothed on scales {buildrel > over {˜}} 5 h^{-1}{Mpc}.(ii) all non-linear back-in-time reconstructions tested here, produce comparable enhancement of the baryonic oscillation signal in the correlation function.

  18. Three-dimensional tomographic reconstruction through two-dimensional multiresolution backprojection steps according to Marr's method

    NASA Astrophysics Data System (ADS)

    Stephanakis, Ioannis M.; Anastassopoulos, George C.

    2009-03-01

    A novel algorithm for 3-D tomographic reconstruction is proposed. The proposed algorithm is based on multiresolution techniques for local inversion of the 3-D Radon transform in confined subvolumes within the entire object space. Directional wavelet functions of the form ψm,nj(x)=2j/2ψ(2jwm,nx) are employed in a sequel of double filtering and 2-D backprojection operations performed on vertical and horizontal reconstruction planes using the method suggested by Marr and others. The densities of the 3-D object are found initially as backprojections of coarse wavelet functions of this form at directions on vertical and horizontal planes that intersect the object. As the algorithm evolves, finer planar wavelets intersecting a subvolume of medical interest within the original object may be used to reconstruct its details by double backprojection steps on vertical and horizontal planes in a similar fashion. Reduction in the complexity of the reconstruction algorithm is achieved due to the good localization properties of planar wavelets that render the details of the projections with small errors. Experimental results that illustrate multiresolution reconstruction at four successive levels of resolution are given for wavelets belonging to the Daubechies family.

  19. Fungal osteomyelitis after arthroscopic anterior cruciate ligament reconstruction: a case report with review of the literature.

    PubMed

    Sun, Lei; Zhang, Lei; Wang, Kai; Wang, Wei; Tian, Min

    2012-10-01

    Fungal osteomyelitis is a very rare complication after anterior cruciate ligament (ACL) reconstruction associated with catastrophic consequences. Herein, we present a case of such disastrous complication after ACL reconstruction. A 23-year-old man developed fever, swelling and pain of the affected knee from 18 days after arthroscopic ACL reconstruction. Therefore, he underwent arthroscopic debridement, removal of the graft and internal fixators, irrigation and suction drainage, successively. Negative results for serial bacterial cultures and smear examinations are obtained. However, computer tomography and X-ray examination showed massive bone destruction at 48 days after ACL reconstruction. As the first open debridement was performed at 50 days after ACL reconstruction, fungal infection was diagnosed based on finding Aspergillus hyphae in pathologic examination of the debrided bone sample. After the final debridement, a 12-cm bone loss in the distal femur was treated by Ilizarov's bone transport. The patient got solid arthrodesis of the affected knee without clinical infection at a year after the initial operation. In addition, a review of the literature regarding case reports of fungal osteomyelitis after ACL reconstruction is presented.

  20. The use of autologous chondrocyte implantation following and combined with anterior cruciate ligament reconstruction

    PubMed Central

    Bartlett, W.; Gooding, C. R.; Sood, M.; Skinner, J. A.; Carrington, R. W.J.; Briggs, T. W.R.; Bentley, G.

    2005-01-01

    We report our experience of using autologous chondrocyte implantation (ACI) to treat osteochondral defects of the knee in combination with anterior cruciate ligament (ACL) reconstruction. The outcome of symptomatic osteochondral lesions treated with ACI following previous successful ACL reconstruction is also reviewed. Patients were followed for a mean of 23 months. Nine patients underwent ACL reconstruction in combination with ACI. Mean modified Cincinnati knee scores improved from 42 to 69 following surgery. Seven patients described their knee as better and two as the same. A second group of nine patients underwent ACI for symptomatic articular cartilage defects following previous ACL reconstruction. In this group, the mean modified Cincinnati knee score improved from 53 to 62 after surgery. Six patients described their knee as better and three as worse. Combined treatment using ACI with ACL reconstruction is technically feasible and resulted in sustained improvement in pain and function. The results following previous ACL reconstruction also resulted in clinical improvement, although results were not as good as following the combined procedure. PMID:16320051

  1. A comparison of force reconstruction methods for a lumped mass beam

    SciTech Connect

    Bateman, V.I.; Mayes, R.L.; Carne, T.G.

    1992-11-01

    Two extensions of the force reconstruction method, the Sum of Weighted Accelerations Technique (SWAT), are presented in this paper; and the results are compared to those obtained using SWAT. SWAT requires the use of the structure`s elastic mode shapes for reconstruction of the applied force. Although based on the same theory, the two, new techniques do not rely on mode shapes to reconstruct the applied force and may be applied to structures whose mode shapes are not available. One technique uses the measured force and acceleration responses with the rigid body mode shapes to calculate the scalar weighting vector, so the technique is called SWAT-CAL (SWAT using a CALibrated force input). The second technique uses only the free-decay time response of the structure with the rigid body mode shapes to calculate the scalar weighting vector and is called SWAT-TEEM (SWAT using Time Eliminated Elastic Modes).

  2. A comparison of force reconstruction methods for a lumped mass beam

    SciTech Connect

    Bateman, V.I.; Mayes, R.L.; Carne, T.G.

    1992-01-01

    Two extensions of the force reconstruction method, the Sum of Weighted Accelerations Technique (SWAT), are presented in this paper; and the results are compared to those obtained using SWAT. SWAT requires the use of the structure's elastic mode shapes for reconstruction of the applied force. Although based on the same theory, the two, new techniques do not rely on mode shapes to reconstruct the applied force and may be applied to structures whose mode shapes are not available. One technique uses the measured force and acceleration responses with the rigid body mode shapes to calculate the scalar weighting vector, so the technique is called SWAT-CAL (SWAT using a CALibrated force input). The second technique uses only the free-decay time response of the structure with the rigid body mode shapes to calculate the scalar weighting vector and is called SWAT-TEEM (SWAT using Time Eliminated Elastic Modes).

  3. A marked bounding box method for image data reduction and reconstruction of sole patterns

    NASA Astrophysics Data System (ADS)

    Wang, Xingyue; Wu, Jianhua; Zhao, Qingmin; Cheng, Jian; Zhu, Yican

    2012-01-01

    A novel and efficient method called marked bounding box method based on marching cubes is presented for the point cloud data reduction of sole patterns. This method is characterized in that each bounding box is marked with an index during the process of data reduction and later for use of data reconstruction. The data reconstruction is implemented from the simplified data set by using triangular meshes, the indices being used to search the nearest points from adjacent bounding boxes. Afterwards, the normal vectors are estimated to determine the strength and direction of the surface reflected light. The proposed method is used in a sole pattern classification and query system which uses OpenGL under Visual C++ to render the image of sole patterns. Digital results are given to demonstrate the efficiency and novelty of our method. Finally, conclusion and discussions are made.

  4. A marked bounding box method for image data reduction and reconstruction of sole patterns

    NASA Astrophysics Data System (ADS)

    Wang, Xingyue; Wu, Jianhua; Zhao, Qingmin; Cheng, Jian; Zhu, Yican

    2011-12-01

    A novel and efficient method called marked bounding box method based on marching cubes is presented for the point cloud data reduction of sole patterns. This method is characterized in that each bounding box is marked with an index during the process of data reduction and later for use of data reconstruction. The data reconstruction is implemented from the simplified data set by using triangular meshes, the indices being used to search the nearest points from adjacent bounding boxes. Afterwards, the normal vectors are estimated to determine the strength and direction of the surface reflected light. The proposed method is used in a sole pattern classification and query system which uses OpenGL under Visual C++ to render the image of sole patterns. Digital results are given to demonstrate the efficiency and novelty of our method. Finally, conclusion and discussions are made.

  5. Method and system for progressive mesh storage and reconstruction using wavelet-encoded height fields

    NASA Technical Reports Server (NTRS)

    Baxes, Gregory A. (Inventor); Linger, Timothy C. (Inventor)

    2011-01-01

    Systems and methods are provided for progressive mesh storage and reconstruction using wavelet-encoded height fields. A method for progressive mesh storage includes reading raster height field data, and processing the raster height field data with a discrete wavelet transform to generate wavelet-encoded height fields. In another embodiment, a method for progressive mesh storage includes reading texture map data, and processing the texture map data with a discrete wavelet transform to generate wavelet-encoded texture map fields. A method for reconstructing a progressive mesh from wavelet-encoded height field data includes determining terrain blocks, and a level of detail required for each terrain block, based upon a viewpoint. Triangle strip constructs are generated from vertices of the terrain blocks, and an image is rendered utilizing the triangle strip constructs. Software products that implement these methods are provided.

  6. Method and system for progressive mesh storage and reconstruction using wavelet-encoded height fields

    NASA Technical Reports Server (NTRS)

    Baxes, Gregory A. (Inventor)

    2010-01-01

    Systems and methods are provided for progressive mesh storage and reconstruction using wavelet-encoded height fields. A method for progressive mesh storage includes reading raster height field data, and processing the raster height field data with a discrete wavelet transform to generate wavelet-encoded height fields. In another embodiment, a method for progressive mesh storage includes reading texture map data, and processing the texture map data with a discrete wavelet transform to generate wavelet-encoded texture map fields. A method for reconstructing a progressive mesh from wavelet-encoded height field data includes determining terrain blocks, and a level of detail required for each terrain block, based upon a viewpoint. Triangle strip constructs are generated from vertices of the terrain blocks, and an image is rendered utilizing the triangle strip constructs. Software products that implement these methods are provided.

  7. Femoral and Tibial Tunnel Widening following Anterior Cruciate Ligament Reconstruction using Various Modalities of Fixation: A Prospective Observational Study

    PubMed Central

    Kanthila, Mahesha; Saya, Rama Prakasha; Vidyasagar, JVS

    2016-01-01

    Introduction Bone tunnel enlargement after Anterior Cruciate Ligament Reconstruction (ACL-R) is a well-accepted phenomenon but there are very few published data comparing the extent of tunnel widening by various methods of fixation after ACL-R. Aim To compare the femoral and tibial tunnel widening following ACL-R with different methods of fixation using CT scan. Materials and Methods This one year prospective study included all patients with chronic Anterior Cruciate Ligament (ACL) injury who underwent primary arthroscopic ACL-R using tripled hamstring tendon autograft. The graft was fixed to the tibial tunnel by Interference Screw (IFS) or Suture Disc (SD) and to the femoral tunnel by IFS, SD, Cross-Pin (CP) or Endo-button CL (Smith & Nephew). The widening of the tibial and femoral tunnels in different methods of fixation was assessed by Computed Tomography (CT) at 12 months follow-up; and was compared using paired sample test. Results A total of 63 patients were included in the study of which 58 (92%) were males and 5 (8%) were females, with a mean age of 29.1 ± 5.9 years. The tibial tunnel widening at one year follow-up was 1.680 ± 1.08794 (19.37%) and 1.517 ± 0.94834 mm (17.39%) by IFS and SD methods respectively. Femoral tunnel widening at one year follow-up was 1.294 ± 0.231, 1.809 ± 0.912, 1.320 ± 0.238, 1.779 ± 0.889 mm by IFS, SD, EB, and CP methods respectively. Femoral tunnel widening following suture disc method of fixation was very highly significant (p<0.001) in comparison with other methods. Conclusion Femoral tunnel and tibial tunnel widening varies with different methods of fixation and was maximum with suture disc method compared to others at one year follow-up after ACL-R. PMID:28050456

  8. Low Dose PET Image Reconstruction with Total Variation Using Alternating Direction Method

    PubMed Central

    Yu, Xingjian; Wang, Chenye; Hu, Hongjie; Liu, Huafeng

    2016-01-01

    In this paper, a total variation (TV) minimization strategy is proposed to overcome the problem of sparse spatial resolution and large amounts of noise in low dose positron emission tomography (PET) imaging reconstruction. Two types of objective function were established based on two statistical models of measured PET data, least-square (LS) TV for the Gaussian distribution and Poisson-TV for the Poisson distribution. To efficiently obtain high quality reconstructed images, the alternating direction method (ADM) is used to solve these objective functions. As compared with the iterative shrinkage/thresholding (IST) based algorithms, the proposed ADM can make full use of the TV constraint and its convergence rate is faster. The performance of the proposed approach is validated through comparisons with the expectation-maximization (EM) method using synthetic and experimental biological data. In the comparisons, the results of both LS-TV and Poisson-TV are taken into consideration to find which models are more suitable for PET imaging, in particular low-dose PET. To evaluate the results quantitatively, we computed bias, variance, and the contrast recovery coefficient (CRC) and drew profiles of the reconstructed images produced by the different methods. The results show that both Poisson-TV and LS-TV can provide a high visual quality at a low dose level. The bias and variance of the proposed LS-TV and Poisson-TV methods are 20% to 74% less at all counting levels than those of the EM method. Poisson-TV gives the best performance in terms of high-accuracy reconstruction with the lowest bias and variance as compared to the ground truth (14.3% less bias and 21.9% less variance). In contrast, LS-TV gives the best performance in terms of the high contrast of the reconstruction with the highest CRC. PMID:28005929

  9. A practical MRI-based reconstruction method for a new endocavitary and interstitial gynaecological template

    PubMed Central

    Richart, Jose; Otal, Antonio; Rodriguez, Silvia; Nicolás, Ana Isabel; DePiaggio, Marina; Santos, Manuel; Vijande, Javier; Perez-Calatayud, Jose

    2015-01-01

    Purpose There are perineal templates for interstitial implants such as MUPIT and Syed applicators. Their limitations are the intracavitary component deficit and the necessity to use computed tomography (CT) for treatment planning since both applicators are non-magnetic resonance imaging (MRI) compatibles. To overcome these problems, a new template named Template Benidorm (TB) has been recently developed. Titanium needles are usually reconstructed based on their own artifacts, mainly in T1-weighted sequence, using the void on the tip as the needle tip position. Nevertheless, patient tissues surrounding the needles present heterogeneities that complicate the accurate identification of these artifact patterns. The purpose of this work is to improve the titanium needle reconstruction uncertainty for the TB case using a simple method based on the free needle lengths and typical MRI pellets markers. Material and methods The proposed procedure consists on the inclusion of three small A-vitamin pellets (hyperintense on MRI images) compressed by both applicator plates defining the central plane of the plate's arrangement. The needles used are typically 20 cm in length. For each needle, two points are selected defining the straight line. From such line and the plane equations, the intersection can be obtained, and using the free length (knowing the offset distance), the coordinates of the needle tip can be obtained. The method is applied in both T1W and T2W acquisition sequences. To evaluate the inter-observer variation of the method, three implants of T1W and another three of T2W have been reconstructed by two different medical physicists with experience on these reconstructions. Results and conclusions The differences observed in the positioning were significantly smaller than 1 mm in all cases. The presented algorithm also allows the use of only T2W sequence either for contouring or reconstruction purposes. The proposed method is robust and independent of the visibility

  10. Common Deficiencies in Existing Methods for Reconstructing High-Resolution Temperature Fields During the Last Millennium

    NASA Astrophysics Data System (ADS)

    Smerdon, J. E.; Kaplan, A.; Zorita, E.; Gonzalez-Rouco, F. J.; Evans, M. N.

    2009-12-01

    Paleoclimatic reconstructions of hemispheric and global surface temperatures during the last millennium vary significantly in their estimates of decadal-to-centennial variability. Although several estimates are based on spatially-resolved climate field reconstruction (CFR) methods, comparisons have been limited to mean Northern Hemisphere temperatures. Spatial skill is explicitly investigated for four CFR methods using pseudoproxy experiments derived from two millennial-length coupled Atmosphere-Ocean General Circulation Model (AOGCM) simulations. The adopted pseudoproxy network approximates the spatial distribution of a widely used multi-proxy network and the CFRs target annual temperature variability on a 5-degree latitude-longitude grid. Results indicate that the spatial skill of presently available large-scale CFRs depends on proxy type and location, target data, and the employed reconstruction methodology, although there are widespread consistencies in the general performance of all four methods. While results are somewhat sensitive to the ability of the AOGCMs to resolve ENSO and its teleconnections, important areas such as the ocean basins and much of the Southern Hemisphere are reconstructed with particularly poor skill in both model experiments. New high-resolution proxies from poorly sampled regions may be one of the best means of improving estimates of large-scale CFRs of the last millennium.

  11. A fast, accurate, and reliable reconstruction method of the lumbar spine vertebrae using positional MRI.

    PubMed

    Simons, Craig J; Cobb, Loren; Davidson, Bradley S

    2014-04-01

    In vivo measurement of lumbar spine configuration is useful for constructing quantitative biomechanical models. Positional magnetic resonance imaging (MRI) accommodates a larger range of movement in most joints than conventional MRI and does not require a supine position. However, this is achieved at the expense of image resolution and contrast. As a result, quantitative research using positional MRI has required long reconstruction times and is sensitive to incorrectly identifying the vertebral boundary due to low contrast between bone and surrounding tissue in the images. We present a semi-automated method used to obtain digitized reconstructions of lumbar vertebrae in any posture of interest. This method combines a high-resolution reference scan with a low-resolution postural scan to provide a detailed and accurate representation of the vertebrae in the posture of interest. Compared to a criterion standard, translational reconstruction error ranged from 0.7 to 1.6 mm and rotational reconstruction error ranged from 0.3 to 2.6°. Intraclass correlation coefficients indicated high interrater reliability for measurements within the imaging plane (ICC 0.97-0.99). Computational efficiency indicates that this method may be used to compile data sets large enough to account for population variance, and potentially expand the use of positional MRI as a quantitative biomechanics research tool.

  12. A Method for 3D Histopathology Reconstruction Supporting Mouse Microvasculature Analysis

    PubMed Central

    Xu, Yiwen; Pickering, J. Geoffrey; Nong, Zengxuan; Gibson, Eli; Arpino, John-Michael; Yin, Hao; Ward, Aaron D.

    2015-01-01

    Structural abnormalities of the microvasculature can impair perfusion and function. Conventional histology provides good spatial resolution with which to evaluate the microvascular structure but affords no 3-dimensional information; this limitation could lead to misinterpretations of the complex microvessel network in health and disease. The objective of this study was to develop and evaluate an accurate, fully automated 3D histology reconstruction method to visualize the arterioles and venules within the mouse hind-limb. Sections of the tibialis anterior muscle from C57BL/J6 mice (both normal and subjected to femoral artery excision) were reconstructed using pairwise rigid and affine registrations of 5 µm-thick, paraffin-embedded serial sections digitized at 0.25 µm/pixel. Low-resolution intensity-based rigid registration was used to initialize the nucleus landmark-based registration, and conventional high-resolution intensity-based registration method. The affine nucleus landmark-based registration was developed in this work and was compared to the conventional affine high-resolution intensity-based registration method. Target registration errors were measured between adjacent tissue sections (pairwise error), as well as with respect to a 3D reference reconstruction (accumulated error, to capture propagation of error through the stack of sections). Accumulated error measures were lower (p<0.01) for the nucleus landmark technique and superior vasculature continuity was observed. These findings indicate that registration based on automatic extraction and correspondence of small, homologous landmarks may support accurate 3D histology reconstruction. This technique avoids the otherwise problematic “banana-into-cylinder” effect observed using conventional methods that optimize the pairwise alignment of salient structures, forcing them to be section-orthogonal. This approach will provide a valuable tool for high-accuracy 3D histology tissue reconstructions for

  13. Quantifying Quadriceps Muscle Strength in Patients With ACL Injury, Focal Cartilage Lesions, and Degenerative Meniscus Tears

    PubMed Central

    Eitzen, Ingrid; Grindem, Hege; Nilstad, Agnethe; Moksnes, Håvard; Risberg, May Arna

    2016-01-01

    Background: Reduced quadriceps strength influences knee function and increases the risk of knee osteoarthritis. Thus, it is of significant clinical relevance to precisely quantify strength deficits in patients with knee injuries. Purpose: To evaluate isokinetic concentric quadriceps muscle strength torque values, assessed both from peak torque and at specific knee flexion joint angles, in patients with anterior cruciate ligament (ACL) injury, focal cartilage lesions, and degenerative meniscus tears. Study Design: Cohort study; Level of evidence, 3. Methods: Da