Objective
Patellar maltracking is an important subset of patellofemoral pain syndrome. We hypothesize that maltracking patients have an increased incidence of extensor mechanism dysfunction due to ...repetitive attempts at stabilization of the patella. Our purpose is to delineate imaging features to identify maltracking patients at risk for extensor mechanism tendinopathy.
Materials and methods
Retrospective review of knee MRIs performed for anterior knee pain over a year was conducted to identify 218 studies with imaging findings of maltracking. The cases were evaluated for the presence and degree of patellar and quadriceps tendinopathy, tibial tuberosity-trochlear groove distance (TT-TG) and the distribution and grade of patellofemoral chondrosis. Cases were compared to 100 healthy, age-matched control knee MRIs.
Results
The mean age of maltracking patients with either patellar or quadriceps tendinosis was 41.2 years versus 48.2 years in the control population (
p
= 0.037). The TT-TG was significantly higher in maltracking patients with either patellar or quadriceps tendinosis at 16.49 mm versus 14.99 mm (
p
= 0.006
).
Maltrackers with isolated lateral patellofemoral chondrosis had a higher mean TT-TG at 17.4 mm versus 15.4 mm (
p
= 0.007). Extensor mechanism tendinosis was increased in the maltracking population compared to the controls at 57.8% versus 27.3% (
p
= 0.004).
Conclusion
Extensor mechanism tendinosis is more common in the maltracking population and occurs at a younger age. TT-TG distance is significantly increased in patients with extensor mechanism dysfunction and in patients with isolated lateral patellofemoral chondrosis. TT-TG measurement can be used independently to identifying maltrackers who may be at risk for future complications.
► Microwave-assisted pyrolysis of corn stover was studied in a bench-top system. ► Exothermic reactions were observed during microwave-assisted pyrolysis. ► Exothermic reactions can sustain the ...pyrolysis reactions without external heat. ► Liquids were collected at different times to extract desirable products.
Microwave-Assisted Pyrolysis (MAP) is a highly scalable process that has the potential to realize the Distributed Biomass Energy Production System (DBEPS) concept. This study was to illustrate the heating properties of MAP when applied to biomass, and to demonstrate the feasibility of manipulating the heating operation to fully utilize exothermic reactions as a means to save energy. Alternate microwave heating of corn stover revealed exothermic reactions occurring in temperature ranges of 188.4–224.0°C and 367.0–387.0°C. These exothermic reactions can potentially sustain the pyrolysis reactions in the absence of external heat sources, indicating that alternative dielectric heating is a practical energy-saving operation mode for MAP. Analysis of the liquid products obtained from different heating intervals suggests that it is possible to selectively extract the primary pyrolysis products by collecting the condensables at specific heating times. The solid chars produced during MAP have desirable microwave absorbent properties and could be recycled in the MAP process.
Advanced MR imaging of the cruciate ligaments Roberts, Catherine C; Towers, Jeffrey D; Spangehl, Mark J ...
Magnetic resonance imaging clinics of North America,
02/2007, Letnik:
15, Številka:
1
Journal Article
Recenzirano
The anterior and posterior cruciate ligaments are crucial stabilizers of the knee. These ligaments are named by the location of their tibial attachments. Each ligament is composed of separate ...functional bundles that differ in size but are equally important in function. MR imaging is accurate and sensitive, making it the imaging technique of choice for evaluating these ligaments. Acute and chronic injuries involving the cruciate ligaments have typical appearances and associated findings. MR imaging interpretation must take into account atypical injuries and imaging pitfalls. Knowledge of normal ligament reconstruction techniques allows differentiation of the normal postoperative appearance from reconstruction failure and complications. Ligament reconstruction techniques, complications, and appearances are reviewed in this article.
Postdiscography infection is an uncommon complication. Magnetic resonance (MR) imaging is often the modality of choice for evaluating spinal infection. Discography entails disc access and fluid ...injection that could alter the baseline MR imaging appearance of the spine and be confounded for infection. Our purpose was to describe the MR imaging findings of the lumbar spine subsequent to uncomplicated discography and to determine if this may mimic infection.
In a prospective cohort study of eight adults (age 22-64 years, mean 45 years) with 22 intradiscal injections, all subjects underwent routine unenhanced and contrast-enhanced MR imaging during the 2-3 week interval postdiscography. A subset of four returned for additional MR imaging during the 4-8 week interval postdiscography. MR images were reviewed for intradiscal, endplate, marrow, and epidural findings and then compared with prediscography examinations. Infection was excluded by clinical documentation.
Postdiscography MR imaging showed that almost all levels were similar to baseline prediscography examinations. No levels developed new vertebral marrow edema, fluid-like intradiscal signal, endplate irregularity, or epidural abnormality. Two subjects simulated potential discitis, but these findings were unchanged from prediscography and were related to prior surgery.
Uncomplicated lumbar spine discography does not cause MR imaging changes that simulate discitis.
Urban climates are driven by micro-meteorological processes associated with the complex urban form, materials, and land cover patterns. Given its close link to the surface energy balance, surface ...temperature observations are key to the improvement and evaluation of models. This work contributes to the application of ground-based thermography in urban settings as an observational method to further our understanding of urban climate processes. In this thesis, ground-based thermography observations are collected and interpreted in a unique way so that they are relatable to scales used by urban climate models and earth observation (EO) satellites. At two measurement sites (simplified outdoor scale model and complex central urban setting), variations in surface temperature are quantitatively linked to micro-scale features such as shadow patterns and material characteristics at unprecedented levels of detail. Previous studies with low level of detail have inferred these properties. The detected upwelling longwave radiation is corrected to surface temperature (Ts) using a novel, high-resolution three-dimensional (3D) radiative transfer (RT) approach. From multi-day observational evaluation, the atmospheric correction has 0.39 K mean absolute error. Ground-based observations are combined with a comprehensive 3D radiative transfer model, enabling detailed simulation of EO land surface temperature (TsEO). For a mainly clear-sky summer day, TsEO at night underestimates the unbiased “complete” surface temperature (Tc) by 0.5 – 1 K, is similar to Tc during morning and evening, and for other times varies significantly with view angle (up to 5.1 K). Generally, view angle variation is smaller than prior studies as they typically use simpler geometry and temperature descriptions, and lack vegetation. Here, the observational basis and high-resolution modelling in a real central urban setting serves as a benchmark for future improvements of simplified model parameterisations.
Purpose
: To update our experience using postoperative irradiation in selected patients with carcinomas of the parotid gland. Outcomes of treatment with a focus on the effectiveness of the two ...primary techniques of radiation used for treating these tumors were evaluated.
Methods and Materials
: A retrospective analysis of 166 patients with parotid gland malignancies treated in the Department of Radiotherapy at the University of Texas M. D. Anderson Cancer Center between 1965–1989 was performed. All patients were treated following surgery and did not have macroscopic disease at the time of their radiation. The most common histologies were mucoepidermoid carcinoma (28%) and adenocarcinoma (27%). Pathologic features constituting indications for postoperative radiotherapy included: inadequate margins, 104 (63%) cases; extraglandular disease extension, 82 (49%); perineural invasion 57 (34%); and nodal disease 43 (26%). Radiation was delivered through an ipsilateral field of predominantly high energy electrons in 142 patients (86%). Wedged paired
60Co fields were used to treat 19 patients. The median dose was 60 Gy, typically delivered at 2 Gy per fraction. The median follow-up time for surviving patients was 155 months.
Results
: Forty-seven (29%) patients had disease recurrence, of whom 15 (9%) had disease recur locally and 10 (6%) regionally (neck). There was no association between the dose of radiation and local failure, except for a trend for patients with positive margins and/or named nerve involvement to have improved local control if they received doses >60 Gy. There was no difference in failure rates in patients treated with wedged pair techniques or ipsilateral fields, but there was a higher complication rate in the former. Overall, 37 patients (22%) developed chronic sequelae attributed to radiation. Twelve patients developed decreased hearing, and 15 patients developed soft tissue or bone necrosis or exposure.
Conclusions
: Local and regional control rates for high risk patients with parotid gland carcinomas treated with radiation following surgery were excellent. The technique of using an ipsilateral field encompassing the parotid bed and treated with high energy electrons often mixed with photons was effective minimal severe late toxicity. The moderate complication rate experienced in this series can be further reduced using modern techniques as described.
To compare, in a cadaveric model, magnetic resonance (MR) imaging techniques with differing contrast and spatial resolution properties in the evaluation of disruption of the lateral ulnar collateral ...ligament (LUCL) at the elbow.
LUCL tears were surgically created in eight of 28 cadaveric elbow specimens. All specimens underwent 1.5-T MR imaging with the following pulse sequences: T1-weighted spin echo (SE), intermediate-weighted fast SE, fat-suppressed T2-weighted fast SE, gradient-recalled echo (GRE) with high spatial resolution, intermediate-weighted fast SE with high spatial resolution, and fat-suppressed T1-weighted SE with intraarticular administration of gadopentetate dimeglumine (MR arthrography). All images were obtained in the oblique coronal plane. Two radiologists independently graded the LUCL with separate and side-by-side assessment.
Areas under the receiver operating characteristic curve were as follows for readers A and B, respectively: T1-weighted SE imaging, 0.64 and 0.62; intermediate-weighted fast SE imaging, 0.87 and 0.67; T2-weighted fast SE imaging, 0.68 and 0.69; GRE imaging, 0.56 and 0.68; MR arthrography, 0.84 and 0.85; and intermediate-weighted imaging with high spatial resolution, 0.92 and 0.88. Interobserver reliability was poor with T1-weighted SE imaging (kappa = 0.13) and GRE imaging (kappa = 0.18), fair with T2-weighted fast SE imaging (kappa = 0.36), and moderate with MR arthrography (kappa = 0.46), intermediate-weighted fast SE imaging (kappa = 0.55), and intermediate-weighted imaging with high spatial resolution (kappa = 0.59).
Intermediate-weighted imaging with high spatial resolution and MR arthrography showed the greatest overall ability to enable the diagnosis of LUCL tears.
Spotted wing drosophila,
Drosophila suzukii
, is an invasive insect that attacks ripe, small fruit such as raspberries, blackberries and blueberries. Little is known about its foraging ecology and ...current trapping methods and monitoring systems are ineffective at commercial scales. In semi-field studies, we evaluated adult alightment and ovipositional preference within and among raspberry plants using sentinel Tangletrap-coated and clean raspberry fruit, respectively, positioned within the exterior and interior plant canopy at four different heights (60, 85, 110 and 135 cm from the base) and conducted in field cages using sexually mature adults. Alightment of adults on Tangle-trap-coated fruit indicated a preference for fruit positioned at lower heights and/or interior locations based on significantly greater numbers being captured on sentinel sticky-coated berries at the two lowest heights. Oviposition in clean raspberry fruit also yielded a similar pattern. In mark-release-recapture studies conducted in the field, spotted wing drosophila prefer sentinel sticky fruit positioned on exterior rows as they alighted on these berries in significantly greater numbers than fruit at in the central portion of the plot. Likewise, in field trials with wild fly populations, infestations were significantly greater in edge rows compared with interior rows. Collectively, our results suggest that monitoring and behaviorally based management strategies may be more effective if they target adults foraging in the lower canopy of small fruit plants located on the crop perimeter.
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