Transaction-neutral implanted data collection interface as EMR driver: a model for emerging distributed medical technologies.

Electronic Medical Record (EMR) and Electronic Health Record (EHR) adoption continues to lag across the US. Cost, inconsistent formats, and concerns about control of patient information are among the most common reasons for non-adoption in physician practice settings. The emergence of wearable and implanted mobile technologies, employed in distributed environments, promises a fundamentally different information infrastructure, which could serve to minimize existing adoption resistance. Proposed here is one technology model for overcoming adoption inconsistency and high organization-specific implementation costs, using seamless, patient controlled data collection. While the conceptual applications employed in this technology set are provided by way of illustration, they may also serve as a transformative model for emerging EMR/EHR requirements.

Technology assessment of resources for the emerging US e-health infrastructure: a proposed interoperability model.

Recent mandates in the USA related to the creation of a National Health Information Infrastructure (NHII) highlight the need for seamless interconnection of healthcare providers. As a necessary precondition, however, an interoperable infrastructure is needed to help clinicians get access to critical healthcare information upon which their clinical and/or treatment decisions can be based. Relatively little has been done to identify or assess commercially available technologies that might work together to meet the required interoperability requirements. In this exploratory technology assessment we examine three core technologies that could serve as a foundation for secure NHII interoperability: Source-Independent Access Control (SIAC), vault process technology and database-independent multimedia capability.

Quantifying the effect of posture on intracranial physiology in humans by MRI flow studies.

PURPOSE: To quantify the effect of posture on intracranial physiology in humans by MRI, and demonstrate the relationship between intracranial compliance (ICC) and pressure (ICP), and the pulsatility of blood and CSF flows. MATERIALS AND METHODS: Ten healthy volunteers (29+/-7 years old) were scanned in the supine and sitting positions using a vertical gap MRI scanner. Pulsatile blood and CSF flows into and out from the brain were visualized and quantified using time-of-flight (TOF) and cine phase-contrast techniques, respectively. The total cerebral blood flow (tCBF), venous outflow, ICC, and ICP for the two postures were then calculated from the arterial, venous, and CSF volumetric flow rate waveforms using a previously described method. RESULTS: In the upright posture, venous outflow is considerably less pulsatile (57%) and occurs predominantly through the vertebral plexus, while in the supine posture venous outflow occurs predominantly through the internal jugular veins. A slightly lower tCBF (12%), a considerably smaller CSF volume oscillating between the cranium and the spinal canal (48%), and a much larger ICC (2.8-fold) with a corresponding decrease in the MRI-derived ICP values were measured in the sitting position. CONCLUSION: The effect of posture on intracranial physiology can be quantified by MRI because posture-related changes in ICC and ICP strongly affect the dynamics of cerebral blood and CSF flows. This study provides important insight into the coupling that exists between arterial, venous, and CSF flow dynamics, and how it is affected by posture.

Magnetic resonance imaging-based measurements of cerebrospinal fluid and blood flow as indicators of intracranial compliance in patients with Chiari malformation.

OBJECT: The diagnosis of Chiari malformation (CM) is based on the degree of tonsilar herniation, although this finding does not necessarily correlate with the presence or absence of symptoms. Intracranial compliance (ICC) and local craniocervical hydrodynamic parameters derived using magnetic resonance (MR) imaging flow measurements were assessed in symptomatic patients and control volunteers to evaluate the role of these factors in the associated pathophysiology. METHODS: Seventeen healthy volunteers and 34 symptomatic patients with CM were studied using a 1.5-tesla MR imager. Cine phase-contrast images of blood and cerebrospinal fluid (CSF) flow to and from the cranium were used to quantify local hydrodynamic parameters (for example, cord displacement and systolic CSF velocity and flow rates) and ICC. The ICC was derived using a previously described method that measures the small, natural changes in intracranial volume and pressure with each cardiac cycle. Differences in the average cord displacement and systolic CSF velocity and flow, comparing healthy volunteers and patients with CM were not statistically significant. Note, however, that a statistically significant lower ICC (20%) was observed in patients compared with controls. CONCLUSIONS: Previous investigators have focused on CSF flow velocities and cord displacement to explain the pathogenesis of CM. Analysis of results have indicated that ICC is more sensitive than local hydrodynamic parameters to changes in the craniospinal biomechanical properties in symptomatic patients. The authors concluded that decreased ICC better explains CM pathophysiology than local hydrodynamic parameters such as cervical CSF velocities and cord displacement. Low ICC also better explains the onset of symptoms in adulthood given the decline in ICC with aging.

Evaluating the effect of decompression surgery on cerebrospinal fluid flow and intracranial compliance in patients with chiari malformation with magnetic resonance imaging flow studies.

OBJECTIVE: To quantify the effect of decompression surgery on craniocervical junction hydrodynamics and on global intracranial compliance (ICC) in patients with Chiari I malformation by use of magnetic resonance measurements of cerebrospinal fluid and blood flow. Studying the effect of decompression surgery may improve our understanding of the pathophysiological characteristics of Chiari I malformation and aid in identifying patients who will benefit from the procedure. METHODS: Twelve patients were studied with a 1.5-T magnetic resonance imaging scanner before and after decompression surgery. Cine phase contrast magnetic resonance images were used to quantify maximum cord displacement, maximum systolic cerebrospinal fluid velocity and volumetric flow rate, and overall ICC. ICC was derived by use of a previously reported method that measures small changes in intracranial volume and pressure that occur naturally with each cardiac cycle. RESULTS: After surgery, changes were documented both in the local hydrodynamic parameters and in ICC. However, only the change in ICC, an average increase of more than 60%, was statistically significant. Increased ICC, which was associated with improved outcome, was measured in 10 of the 12 patients, no significant change was documented in 1 patient, and decreased ICC was measured in 1 patient whose symptoms persisted after surgery. CONCLUSION: An increase in the overall compliance of the intracranial compartment is the most significant and consistent change measured after decompression surgery. Changes in cord displacement, cerebrospinal fluid velocities, and flow in the craniospinal junction were less consistent and less affected by the operation. Thus, ICC may play an important role in the outcome of decompression surgery related to improving symptoms and restoring normal neurological hydrodynamics in patients with Chiari I malformations.

Brain tumor demarcation by applying a LAMSTAR neural network to spectroscopy data.

The application of optical spectroscopy for intra-operatively delineating brain tumors has been studied in this paper. The classification of tissue as normal, tumor and boundary is done using the LAMSTAR neural network (NN). The objective is to combine both fluorescence and reflectance as attributes to be used for the demarcation, thus giving the identification greater specificity and sensitivity. The input word has seven sub-words, five with autofluorescence parameters and two with reflectance values. The mean and standard deviation for the fluorescence parameters that were used for setting the weights of the NN were obtained from previous work. The reflectance value was used with the fluorescence parameters through a two-step discrimination algorithm. The neural network was trained with 10 sets of each tumor, normal and boundary type of tissue parameters. The network was then tested with 15 complete input sets and 10 incomplete sets for the identification. A 100% success rate was obtained for the complete testing sets and 80% for the incomplete ones. The most significant self-organizing map layers of the network were also identified for each decision. A sensitivity of 97.1% and specificity of 94.73% were achieved, which is much higher than earlier published results of 89 and 76%, respectively.

Noninvasive intracranial compliance and pressure based on dynamic magnetic resonance imaging of blood flow and cerebrospinal fluid flow: review of principles, implementation, and other noninvasive approaches.

Current techniques for intracranial pressure (ICP) measurement are invasive. All require a surgical procedure for placement of a pressure probe in the central nervous system and, as such, are associated with risk and morbidity. These considerations have driven investigators to develop noninvasive techniques for pressure estimation. A recently developed magnetic resonance (MR) imaging-based method to measure intracranial compliance and pressure is described. In this method the small changes in intracranial volume and ICP that occur naturally with each cardiac cycle are considered. The pressure change during the cardiac cycle is derived from the cerebrospinal fluid (CSF) pressure gradient waveform calculated from the CSF velocities. The intracranial volume change is determined by the instantaneous differences between arterial blood inflow, venous blood outflow, and CSF volumetric flow rates into and out of the cranial vault. Elastance (the inverse of compliance) is derived from the ratio of the measured pressure and volume changes. A mean ICP value is then derived based on a linear relationship that exists between intracranial elastance and ICP. The method has been validated in baboons, flow phantoms, and computer simulations. To date studies in humans demonstrate good measurement reproducibility and reliability. Several other noninvasive approaches for ICP measurement, mostly nonimaging based, are also reviewed. Magnetic resonance imaging-based ICP measurement may prove valuable in the diagnosis and serial evaluation of patients with a variety of disorders associated with alterations in ICP.