Effects of telemetric epicardial leads and ventricular catheters on arrhythmia incidence in cynomolgus monkeys.

Introduction: Utilization of implantable bio-telemetry devices represents a common approach to contemporary cardiovascular safety assessment. Depending on the specific needs of the study design, and corresponding surgical methodologies employed, application of telemetry devices may have more or less liability to interact with ongoing physiology. The potential for intrathoracic procedures (epicardial/intracardiac ECG lead arrangements, left ventricular catheterization) to influence baseline cardiovascular function, and particularly arrhythmia status is currently an important topic of consideration.

Two-year results of X-stop interspinous implant for the treatment of lumbar spinal stenosis: a prospective study.

Study Design: Prospective Observational Study.

Objective: To prospectively assess the clinical outcome of patients treated for symptomatic spinal stenosis with the X-stop device.

Summary Of Background Data: The X-stop device is used in the treatment of symptomatic lumbar spinal stenosis.

The use of pMRI to validate the identification of palpated bony landmarks.

Accurate palpation of lumbar spinous processes (SPs) is a key component of spinal assessment. It is also vital for the accurate measurement of spinal motion when using external skin marker-based measurement systems, which are being increasingly used to understand low back disorders and their management. The aim was to assess the accuracy of lumbar spinous process (SP) palpation using positional magnetic resonance imagery (MRI) (pMRI).

Low back pain: an assessment using positional MRI and MDT.

Current guidelines advise against the use of routine imaging for low back pain. Positional MRI can provide enhanced assessment of the lumbar spine in functionally loaded positions which are often relevant to the presenting clinical symptoms. The purpose of this case report is to highlight the use of positional MRI in the assessment and classification of a subject with low back pain.

Upright MRI in kinematic assessment of the ACL-deficient knee.

The ability to quantify in vivo femoro-tibial relations in the knee holds great advantage to further patient care. There is little consensus on the optimal weight-bearing environment and measurement method for MRI assessment of in vivo knee kinematics. This study set out to establish the optimal method of measuring femoro-tibial relations in an upright, weight-bearing environment in normal individuals and those with ACL deficiency.

Early MRI in the management of the clinical scaphoid fracture.

Objectives: The 'clinical scaphoid fracture' remains a common problem faced by emergency physicians. Early magnetic resonance imaging (MRI) has been used to routinely investigate such patients presenting to the emergency department of Aberdeen Royal Infirmary since 2002. The aim of this study was to evaluate the effectiveness of this strategy in the diagnosis of occult scaphoid fracture.

Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on magnetic resonance images.

Study Design: Retrospective radiologic study on a prospective patient cohort.

Objective: To devise a qualitative grading of lumbar spinal stenosis (LSS), study its reliability and clinical relevance.

Summary Of Background Data: Radiologic stenosis is assessed commonly by measuring dural sac cross-sectional area (DSCA).

The increase in dural sac area is maintained at 2 years after X-stop implantation for the treatment of spinal stenosis with no significant alteration in lumbar spine range of movement.

Background Context: The X-stop interspinous process decompression (IPD) device has been used effectively in the management of symptomatic spinal stenosis. This study examines the radiological outcomes at 2 years postoperatively after X-stop implantation.

Purpose: To measure the effect of X-stop IPD device on the dural sac and foraminal areas at 24 months postoperatively at instrumented level in symptomatic lumbar canal stenosis.

Magnetic resonance imaging and stadiometric assessment of the lumbar discs after sitting and chair-care decompression exercise: a pilot study.

Background: Sitting is associated with loss of the lumbar lordosis, intervertebral disc (IVD) compression, and height loss, possibly increasing the risk of lower back pain. With a trend toward more sitting jobs worldwide, practical strategies for preventing lumbar flattening and potentially associated low back pain (LBP) are important.

Purpose: The purpose of this study was to determine the feasibility of using upright magnetic resonance imaging (MRI) and stadiometry to measure changes in height and configuration of the lumbar spine before and after normal sitting and a seated unloading exercise intervention.

The effects of posture and subject-to-subject variations on the position, shape and volume of abdominal and thoracic organs.

In this study, the thorax and the abdomen of nine subjects were imaged in four postures using a positional MRI scanner. The four postures were seated, standing, forward-flexed and supine. They were selected to represent car occupants, pedestrians, cyclists and a typical position for medical imaging, respectively.

The intrinsic shape of the human lumbar spine in the supine, standing and sitting postures: characterization using an active shape model.

The shape of the lumbar spine in the sagittal plane varies between individuals and as a result of postural changes but it is not known how the shape in different postures is related. Sagittal images of the lumbar spines of 24 male volunteers were acquired using a positional magnetic resonance scanner. The subjects were imaged lying supine, standing and sitting.

Spontaneous cardiac arrhythmias recorded in three experimentally- and drug-naive laboratory species (canine, primate, swine) during standard pre-study screening.

Introduction: The purpose of this study was to collect and estimate the general prevalence of spontaneous irregularities in cardiac rhythms in three standard laboratory animal species: Beagle dog (N=2450), cynomolgus monkey (N=1563), and domestic swine (N=704) during standard preclinical screening.

Methods: Standard prestudy Lead II hardwire ECG tracings were collected in purpose-bred, drug-, and experimentally-naive animals following receipt from an institutionally-approved vendor and prior to placement onto general toxicology or safety pharmacology studies over the course of 18 months. The ECGs were independently reviewed by two veterinary cardiologists/internists for the presence or absence of arrhythmias (dysrhythmia), conduction disturbances, or other normal variants or clinically significant waveform changes.

The effect of axial load on the sagittal plane curvature of the upright human spine in vivo.

Determining the effect of load carriage on the human spine in vivo is important for determining spinal forces and establishing potential mechanisms of back injury. Previous studies have suggested that the natural curvature of the spine straightens under load, but are based on modelling and external measurements from the surface of the back. In the current study, an upright positional MRI scanner was used to acquire sagittal images of the lumbar and lower thoracic spine of 24 subjects.

Painful disc lesion: can modern biplanar magnetic resonance imaging replace discography?

Study Design: A new magnetic resonance imaging (MRI) classification of disc degeneration was correlated with discography. It was also studied for intraobserver and interobserver variability in interpreting disc abnormality and for the capability in predicting symptomatic disc.

Objective: To correlate the results of discography with a new MRI classification for disc degeneration and the presence of the vertebral endplate changes and the high intensity zone (HIZ).

Characterizing the shape of the lumbar spine using an active shape model: reliability and precision of the method.

Study Design: Analysis of positional magnetic resonance images of normal volunteers.

Objective: To compare the reliability and precision of an active shape model to that of conventional lordosis measurements.

Summary Of Background Data: Characterization of lumbar lordosis commonly relies on measurement of angles; these have been found to have errors of around 10 degrees .

The response of the nucleus pulposus of the lumbar intervertebral discs to functionally loaded positions.

Study Design: Asymptomatic volunteers underwent magnetic resonance imaging to investigate how different positions affect lumbar intervertebral discs.

Objective: To quantify sagittal migration of the lumbar nucleus pulposus in 6 functional positions.

Summary Of Background Data: Previous studies of the intervertebral disc response in the sagittal plane were limited to imaging of recumbent positions.

One-year results of X Stop interspinous implant for the treatment of lumbar spinal stenosis.

Study Design: Prospective observational study.

Objective: To prospectively assess the clinical outcome of patients with symptomatic lumbar spinal stenosis before and at periodic intervals after X Stop implantation and to compare the data with previous studies.

Summary Of Background Data: The X Stop Interspinous Process Distraction Device is a relatively new interspinous implant designed for patients with symptomatic spinal stenosis particularly neurogenic claudication.

Postural changes of the dural sac in the lumbar spines of asymptomatic individuals using positional stand-up magnetic resonance imaging.

Study Design: Positional magnetic resonance imaging (MRI) study of control subjects.

Objectives: To determine dimensional changes in the lumbar dural sac as a function of posture, and to establish changes between the supine, erect and seated positions.

Summary Of Background Data: Studies using computerized tomography and MRI were done to determine the mechanical effects on the lumbar spinal canal in the different positions.

Cluster analysis as a method for determining size ranges for spinal implants: disc lumbar replacement prosthesis dimensions from magnetic resonance images.

Study Design: Statistical analysis of clinical radiologic data.

Objective: To develop an objective method for finding the number of sizes for a lumbar disc replacement.

Summary Of Background Data: Cluster analysis is a well-established technique for sorting observations into clusters so that the "similarity level" is maximal if they belong to the same cluster and minimal otherwise.

Influence of X Stop on neural foramina and spinal canal area in spinal stenosis.

Study Design: Measurements of cross sections of exit foramen and spinal canal were performed before and after placement of X Stop in physiologic postures using positional MR scanner at the stenosed level in patients with lumbar spinal stenosis.

Objective: To quantify the effect of the implant in vivo on the lumbar spine at the instrumented levels in various postures.

Summary Of Background Data: Dimensions of the spinal canal and neural foramen decrease from flexion to extension.

Positional MRI changes in supine versus sitting postures in patients with degenerative lumbar spine.

Introduction: Back pain is associated with a degree of alteration in the alignment and movement of the lumbar spine. The purpose of this study is to investigate how the degree of lumbar segmental degeneration affects sagittal changes in the lumbar spine as it shifts from the supine to the sitting (load-bearing) posture.

Materials And Methods: Thirty patients with chronic low back pain were enrolled (14 male and 16 female patients); mean age 44.

The length of the cervical cord: effects of postural changes in healthy volunteers using positional magnetic resonance imaging.

Study Design: The length of the cervical cord in healthy volunteers was measured in the supine and erect position using positional magnetic resonance imaging (MRI).

Objective: To assess the relationship between the length of the cervical cord and cervical posture in healthy volunteers.

Summary Of Background Data: A number of detailed descriptions of the normal morphologic features of the cervical cord have been published.

Biomechanical aspects of the cervical cord: effects of postural changes in healthy volunteers using positional magnetic resonance imaging.

Study Design: The area in cross-sectional view of the cervical cord (ACSCC) at each disc levels was measured in supine and erect positions using positional magnetic resonance imaging (pMRI).

Objectives: To assess the relationship between ACSCC and cervical posture in healthy volunteers using pMRI.

Summary Of Background Data: There have been few detailed descriptions of the normal morphologic features of the cervical cord.

Effects of X-STOP device on sagittal lumbar spine kinematics in spinal stenosis.

The X-Stop device is designed to distract the posterior elements of the stenotic segment and place it in flexion to treat neurogenic claudication. Previous biomechanical studies on X Stop have been done in vitro on cadavers looking at disc pressures and segmental range of movements. The objective of this study is to understand the sagittal kinematics in vivo of the lumbar spine at the instrumented and adjacent levels.

Electrocardiogram, hemodynamics, and core body temperatures of the normal freely moving laboratory beagle dog by remote radiotelemetry.

Introduction: The objectives of this study were to provide baseline normative values for circadian changes in the time-series data collected over the course of a normal day in laboratory-housed dogs and to assess the relative efficiency of standard correction formulas to correct for the variations in QT intervals and heart rate functions.

Methods: One hundred and twenty-three beagle dogs (65 M, 58 F) were equipped with radiotelemetry transmitters and continuously monitored, while freely moving in their home cages. Electrocardiograms (ECGs), hemodynamic parameters (diastolic, systolic, and mean arterial pressures) as well as core body temperatures were recorded for 22 h.