Assessing lumbar paraspinal muscle cross-sectional area and fat composition with T1 versus T2-weighted magnetic resonance imaging: Reliability and concurrent validity

Purpose Studies using magnetic resonance imaging to assess lumbar multifidus cross-sectional area frequently utilize T1 or T2-weighted sequences, but seldom provide the rationale for their sequence choice. However, technical considerations between their acquisition protocols could impact on the ability to assess lumbar multifidus anatomy or its fat/muscle distinction. Our objectives were to examine the concurrent validity of lumbar multifidus morphology measures of T2 compared to T1-weighted sequences, and to assess the reliability of repeated lumbar multifidus measures. Methods The lumbar multifidus total cross-sectional area of 45 patients was measured bilaterally at L4 and L5, with histogram analysis determining the muscle/fat threshold values per muscle. Images were later re-randomized and re-assessed for intra-rater reliability. Matched images were visually rated for consistency of outlining between both image sequences. Bland-Altman bias, limits of agreement, and plots were calculated for differences in total cross-sectional area and percentage fat between and within sequences, and intra-rater reliability analysed. Results T1-weighted total cross-sectional area measures were systematically larger than T2 (0.2 cm2), with limits of agreement <±10% at both spinal levels. For percentage fat, no systematic bias occurred, but limits of agreement approached ±15%. Visually, muscle outlining was consistent between sequences, with substantial mismatches occurring in <5% of cases. Intra-rater reliability was excellent (ICC: 0.981–0.998); with bias and limits of agreement less than 1% and ±5%, respectively. Conclusion Total cross-sectional area measures and outlining of muscle boundaries were consistent between sequences, and intra-rater reliability for total cross-sectional area and percentage fat was high indicating that either MRI sequence could be used interchangeably for this purpose. However, further studies comparing the accuracy of various methods for distinguishing fat from muscle are recommended

Efficacy of MRI in primary care for patients with knee complaints due to trauma: Protocol of a randomised controlled non-inferiority trial (TACKLE trial)

Background: Patients with traumatic knee complaints regularly consult their general practitioner (GP). MRI might be a valuable diagnostic tool to assist GPs in making appropriate treatment decisions and reducing costs. Therefore, this study will assess the cost-effectiveness of referral to MRI by GPs compared with usual care, in patients with persistent traumatic knee complaints. Design and methods. This is a multi-centre, open-labelled randomised controlled non-inferiority trial in combination with a concurrent observational cohort study. Eligible patients (aged 18-45 years) have knee complaints due to trauma (or sudden onset) occurring in the preceding 6 months and consulting their GP. Participants are randomised to: 1) an MRI group, i.e. GP referral to MRI, or 2) a usual care group, i.e. no MRI. Primary outcomes are knee-related daily function, medical costs (healthcare use and productivity loss), and quality of life. Secondary outcomes are disability due to knee complaints, severity of knee pain, and patients' perceived recovery and satisfaction. Outcomes are measured at baseline and at 1.5, 3, 6, 9 and 12 months follow-up. Also collected are data on patient demographics, GPs' initial working diagnosis, GPs' preferred management at baseline, and MRI findings. Discussion. In the Netherlands, the additional diagnostic value and cost-effectiveness of direct access to knee MRI for patients presenting with traumatic knee complaints in general practice is unknown. Although GPs increasingly refer patients to MRI, the Dutch clinical guideline 'Traumatic knee complaints' for GPs does not recommend referral to MRI, mainly because the cost-effectiveness is still unknown. Trial registration. Dutch Trial Registration: NTR3689

General Practitioners Referring Adults to MR Imaging for Knee Pain: A Randomized Controlled Trial to Assess Cost-effectiveness

Analysis and support of clinical decision makin

Diagnostic Accuracy of Lumbosacral Spine Magnetic Resonance Image Reading by Chiropractors, Chiropractic Radiologists, and Medical Radiologists

Study Design. A cross-sectional diagnostic accuracy study was conducted in 2 sessions. Objective. It is important to know whether it is possible to accurately detect "specific findings" on lumbosacral magnetic resonance (MR) images and whether the results of different observers are comparable. Summary of Background Data. Health care providers frequently use magnetic resonance imaging in the diagnostic process of patients with low back pain. The use of MR scans is increasing. This leads to an increase in costs and to an increase in risk of inaccurately labeling patients with an anatomical diagnosis that might not be the actual cause of symptoms. Methods. A set of 300 blinded MR images was read by medical radiologists, chiropractors, and chiropractic radiologists in 2 sessions. Each assessor read 100 scans in round 1 and 50 scans in round 2. The reference test was an expert panel. For all analyses, the magnetic resonance imaging findings were dichotomized into "specific findings" or "no specific findings." For the agreement, percentage agreement and ê values were calculated and for validity, sensitivity, and specificity. Sensitivity analysis was done for classifications A and B (prevalence of 31% and 57%, respectively). Results. The intraobserver ê values for chiropractors, chiropractic radiologists, and medical radiologists were 0.46, 0.49, and 0.69 for A and 0.55, 0.75, and 0.64 for B, respectively. The interobserver ê values were lowest for chiropractors (0.28 for A, 0.37 for B) and highest for chiropractic radiologists (0.50 for A, 0.49 for B). The sensitivities of the medical radiologists, chiropractors, and chiropractic radiologists were 0.62, 0.71, and 0.75 for A and 0.70, 0.74, 0.84 for B, respectively. The specificities of medical radiologists, chiropractic radiologists, and chiropractors were 0.82, 0.77, and 0.70 for A and 0.74, 0.52, and 0.61 for B, respectively. Conclusion. Agreement and validity of MR image readings of chiropractors and chiropractic and medical radiologists is modest at best. This study supports recommendations in clinical guidelines against routine use of magnetic resonance imaging in patients with low back pain

‘No-reflow’ after acute myocardial infarction: direct visualisation of microvascular obstruction by gadolinium-enhanced CMR

Cardiovascular magnetic resonance is considered the standard imaging modality in clinical trials to monitor patients after acute myocardial infarction. However, limited data are available with respect to infarct size, presence and extent of microvascular injury (MVO) and changes over time, in relation to cardiac function in optimally treated patients. In the current study we prospectively investigate the change of infarct size over time, and the incidence and significance of MVO in a uniform, optimally treated patient group after AMI. (Neth Heart J 2008;16:179-81.

ScAIN nanowires: A cathodoluminescence study

Contains fulltext : 75904.pdf (publisher's version ) (Closed access)5 p

Scandium aluminum nitride nanowires

Scandium nitride (ScN) and aluminum nitride (AlN) are novel semiconducting materials with tremendous potential for optoelectronic applications. While AlN's bandgap lies in the UV at 6 eV, ScN's bandgap is around 2-2.4 eV. Combinations of these semiconductors can cover most of the visible spectrum (from the UV/violet to up to the color red). This makes the alloying of AlN with ScN an interesting alternative to AlxIn1-xN or InxGa1-xN, the latter of which is currently used for a.o. white light LEDs. The drawback of InN is its poor thermal and chemical stability, whereas ScN is extremely inert and stabile. In this chapter we will introduce the first ever semiconducting Sc x-Al1-xN alloy in the form of nanowires. These nanowires were grown on ScN films, deposited by hydride vapor phase epitaxy on silicon carbide substrates. Though their fabrication was unintentional, we can explain the growth of these ScxAl1-xN nanowires via the formation of nanosized metallic droplets of aluminum on the ScN film. These droplets then acted as catalysts under which the nanowires formed during the final stages of the growth process. The structural properties of these ScxAl1-xN nanowires on ScN films were examined by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), energy dispersive analysis of X-rays (EDX), and X-ray diffraction (XRD). The optical properties were investigated by single nanowire cathodoluminescence (CL).</p