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Abstract Background Altered spinal mobility is thought to be related to current or past episodes of low back pain; however evidence of that relationship in younger subjects has not been established. The purpose of this study was to compare lumbar segmental mobility in asymptomatic and symptomatic subjects during posterior to anterior (PA) manual spinal mobilization and a self-initiated prone press-up (PU) maneuver. We hypothesized that persons with central low back pain would have an altered lumbar segmental mobility pattern compared to those without pain. Method Forty-five individuals (age 32.1 ± 8.5) with non-specific low back pain and 20 persons (age 31.1 ± 7.0) without low back pain participated. Each subject underwent dynamic imaging of the lumbar spine during a PA mobilization procedure and while performing a PU. Segmental motion was quantified as the change in the intervertebral angle between the resting and end-range vertebral positions. Results The symptomatic group had a larger percentage of subjects with evidence of single level segmental hypermobility than the asymptomatic group during the PA (40.0% vs. 5%) and PU (26.7% vs. 15%) procedures. Single lumbar motion-segment analysis revealed hyper-mobility in symptomatic subjects at L5 – S1 (Chi-square = 10.0, p ≤ 0.01) and L4 – L5 (Chi-square = 4.18, p ≤ 0.05) during the PA test. Conclusion Persons with non-specific low back pain have a tendency to demonstrate single level lumbar segmental hypermobility when compared to age specific asymptomatic subjects.

Rationale and Objective: We have installed an improved x-ray/MR (XMR) truly hybrid system with higher imaging signal-to-noise ratio (SNR) and versatility than our first prototype. In our XMR design, a fixed anode x-ray fluoroscopy system is positioned between the two donut-shaped magnetic poles of a 0.5T GE Signa-SP magnet (SP-XMR). This paper describes the methods for increased compatibility between the upgraded x-ray and MR systems that have helped improve patient management. Materials and Methods: A GE OEC 9800 system (GE OEC Salt Lake City, UT) was specially reconfigured for permitting x-ray fluoroscopy inside the interventional magnet. A higher power x-ray tube, a new permanent tube mounting system, automatic exposure control (AEC), remote controlled collimators, choice of multiple frame rates, DICOM image compatibility, magnetically shimmed x-ray detector, x-ray compatible MR coil, and better RF shielding are the highlights of the new system. A total of 23 clinical procedures have been conducted with SP-XMR guidance of which five were performed using the new system. Results: The 70% increased power for fluoroscopy, and a new 6 times higher power single frame imaging mode, has improved imaging capability. The choice of multiple imaging frame rates, AEC, and collimator control allow reduction in x-ray exposure to the patient. The DICOM formatting has permitted easy transfer of clinical images over the hospital PACS network. The increased MR compatibility of the detector and the x-ray transparent MR coil has enabled faster switching between x-ray and MR imaging modes. Conclusion: The improvements introduced in our SP-XMR system have further streamlined x-ray/MR hybrid imaging. Additional clinical procedures could benefit from the new SP-XMR imaging. [Copyright &y& Elsevier]

Cryoablation is one of several minimally invasive treatments that may be suitable for a targeted treatment of prostate cancer. Because efficacy is improved when a sufficiently cold end temperature is reached, the purpose of this work was to demonstrate an image-based thermometry method that could provide temperature maps throughout the frozen tissue. In five in vivo canine prostate cryoablation experiments performed under magnetic resonance imaging guidance, two MR parameters were measured and correlated to temperature: R2* and changes in signal intensity. R2* is elevated approximately linearly as tissue temperature decreases below the freezing point, while the signal intensity decreases exponentially. In vivo temperature maps with isotherms at −5°C, −15°C, and −30°C are demonstrated. [Copyright &y& Elsevier]

Flexion and extension of the spine induce loads to the anterior or posterior spinal column and therefore may affect disc hydration. Information related to the effect of activity on hydration of intervertebral discs could lead to a better understanding of the pathophysiology and rehabilitation of low back injury. A pilot study evaluating the effect of spine position and loading on the changes of disc hydration in vivo was conducted with three volunteers without low back pain history. Spines were scanned in neutral, flexion and extension positions. MRI was repeated after 6 hours of normal activity and 4 hours of heavy activity with a weighted vest. Signal intensities of the intervertebral discs were measured at the L4-5 and L5-S1 levels. The signal intensities decreased by 9.3% at L4-5 and 8.3% at L5-S1 intervertebral discs compared to baseline after 6 hours of daily activity. The intensities decreased more (14.5% and 12.4%) with additional four hours of heavy activity. There was no change in disc signal intensity between neutral, flexion and extension of the spine. This study showed that: 1) rapid fluctuation of load such as between flexion and extension does not change disc hydration 2) prolonged loading of the spine decreases disc hydration. [ABSTRACT FROM AUTHOR]