Accurate state estimation from uncertain data and models: an application of data assimilation to mathematical models of human brain tumors

<p>Abstract</p> <p>Background</p> <p>Data assimilation refers to methods for updating the state vector (initial condition) of a complex spatiotemporal model (such as a numerical weather model) by combining new observations with one or more prior forecasts. We consider the potential feasibility of this approach for making short-term (60-day) forecasts of the growth and spread of a malignant brain cancer (glioblastoma multiforme) in individual patient cases, where the observations are synthetic magnetic resonance images of a hypothetical tumor.</p> <p>Results</p> <p>We apply a modern state estimation algorithm (the Local Ensemble Transform Kalman Filter), previously developed for numerical weather prediction, to two different mathematical models of glioblastoma, taking into account likely errors in model parameters and measurement uncertainties in magnetic resonance imaging. The filter can accurately shadow the growth of a representative synthetic tumor for 360 days (six 60-day forecast/update cycles) in the presence of a moderate degree of systematic model error and measurement noise.</p> <p>Conclusions</p> <p>The mathematical methodology described here may prove useful for other modeling efforts in biology and oncology. An accurate forecast system for glioblastoma may prove useful in clinical settings for treatment planning and patient counseling.</p> <p>Reviewers</p> <p>This article was reviewed by Anthony Almudevar, Tomas Radivoyevitch, and Kristin Swanson (nominated by Georg Luebeck).</p

Sulforhodamine 101 selectively labels human astrocytoma cells in an animal model of glioblastoma

AbstractSulforhodamine 101 (SR101) is a useful tool for immediate staining of astrocytes. We hypothesized that if the selectivity of SR101was maintained in astrocytoma cells, it could prove useful for glioma research. Cultured astrocytoma cells and acute slices from orthotopic human glioma (n=9) and lymphoma (n=6) xenografts were incubated with SR101 and imaged with confocal microscopy. A subset of slices (n=18) were counter-immunostained with glial fibrillary acidic protein and CD20 for stereological assessment of SR101 co-localization. SR101 differentiated astrocytic tumor cells from lymphoma cells. In acute slices, SR101 labeled 86.50% (±1.86; p<0.0001) of astrocytoma cells and 2.19% (±0.47; p<0.0001) of lymphoma cells. SR101-labeled astrocytoma cells had a distinct morphology when compared with in vivo astrocytes. Immediate imaging of human astrocytoma cells in vitro and in ex vivo rodent xenograft tissue labeled with SR101 can identify astrocytic tumor cells and help visualize the tumor margin. These features are useful in studying astrocytoma in the laboratory and may have clinical applications

Pharmacologic and Cell-Based Therapies for Acute Spinal Cord Injury

This article provides a review of current pharmacologic and cell-based modalities used for the management of acute spinal cord injury (SCI). The literature search was focused on clinical trials performed in the United States and Canada. Despite the significant advance in research, there is no definitive treatment option for SCI. Instead, existing pharmacologic and cell-based modalities provide only minimal neurologic recovery benefits. This can be attributed to the complex pathophysiology of SCI and spinal cord regeneration. Further research is imperative to better understand these mechanisms and discover definitive treatment modalities

Placement of Guide-Wireless Sharp Percutaneous Pedicle Screws Utilizing Computed Tomography-Navigation and Sentinel Fluoroscopy: 2-Dimensional Operative Video

Many established techniques exist for minimally invasive pedicle screw placement. Nearly all techniques incorporate the use of a Kershner wire (K-wire) at various points in the work-flow. The use of a K-wire adds an additional step. If its position is lost, it requires repeating all previous steps, and placement is not without complication. The use of a guide-wireless sharp screws allows the surgeon to place a pedicle screw in 1 step with several fluid maneuvers.1 The patient underwent Institutional Review Board-approved consent for this study. Following traditional computed tomography-based navigation, a stab incision is made, followed by fascial dissection with monopolar cautery. The sharp screw is placed percutaneously at the facet-transverse process junction. The precise entry point is confirmed with navigation, followed by a sentinel anterior-posterior fluoroscopic image, verifying the accuracy of the navigation. The cortical bone is traversed by malleting the sharp tip through the cortex. When the cancellous bone is engaged, the screw is then advanced through the pedicle. This set of steps allows for safe, efficient placement of percutaneous pedicle screws without the need for a guidewire. Mal-placement regarding sharp pedicle screw insertion is similar to K-wire-dependent screw placement. Surgeons must be cognoscente of exceptionally sclerotic bone, which can prove difficult to cannulate. Conversely, osteoporotic bone that is liable to a cortical pedicle breach, transverse process fracture, and/or maltrajectory are all considerations when placing a K-wireless, sharp pedicle screw. Anterior-posterior fluoroscopy is utilized to confirm accuracy of image-guided navigation and mitigate malplacement of pedicle screws

Cerebral herniation as a complication of chest tube drainage of cerebrospinal fluid after injury to the spine

BACKGROUND: Patients with concomitant injuries to the thorax and thecal sac requiring chest tube drainage are at risk for cerebral herniation caused by overdrainage of cerebrospinal fluid (CSF). CASE DESCRIPTION: A 40-year-old man presented to the trauma service awake, alert, and oriented with an isolated gunshot wound to the midaxillary line through the tenth intercostal space and a complete spinal cord injury at T12. The patient was stabilized and intubated. A chest tube was placed, and he was transferred to the neurologic intensive care unit. The patient was found to be comatose with complete absence of brainstem reflexes 3 hours after admission. RESULTS: Magnetic resonance imaging (MRI) and autopsy revealed diffuse cerebral edema, occlusion of the bilateral posterior cerebral arteries, and tonsillar herniation extending several centimeters below the foramen magnum, with petechial hemorrhages and absence of gliosis. CONCLUSIONS: To the authors\u27 knowledge, this case represents the first report of cerebral herniation secondary to chest tube drainage of a CSF leak caused by traumatic injury to the thecal sac

Thoracic meningioma with ossification: Case report

BACKGROUND: The incidence of spinal meningiomas is 0.33/100000 population, and ossified spinal meningiomas are even less commonly encountered. CASE DESCRIPTION: A 64-year-old male presented with a progressive T4-level thoracic myelopathy. MR imaging revealed an intradural extramedullary mass that significantly compressed the spinal cord. The accompanying CT demonstrated hyperdensities within the lesion consistent with punctate calcification vs. ossification (i.e. consistent with histological bone formations within tumor). The patient underwent complete resection of the tumor resulting in a full recovery of neurological function within 6 postoperative weeks. The pathological specimen showed findings consistent with an ossified spinal meningioma. CONCLUSION: Here, we identified a rare case of an ossified thoracic T4 meningioma occurring in a 64-year-old male

Use of a tubular retractor for transoral odontoidectomy of upper cervical epidural phlegmon extraction and abscess drainage

Anterior epidural abscess of the superior cervical cord with odontoid osteomyelitis is a rare but potentially devastating condition due to the potential for severe and irreversible neurological injury. Early and aggressive neurosurgical intervention and medical management is usually indicated in cases with symptomatic spinal cord compression and may be associated with superior clinical outcomes. Access to the craniovertebral junction for decompression of the upper cervical cord is complicated by the proximity of critical anatomical structures. The transoral approach is considered to be the standard for treating lesions of the odontoid and anterior epidural space of the superior cervical spine. The use of a tubular retractor for procedures of the craniovertebral junction has been described for several approaches to this region but its use has yet to be described for the transoral approach in a live patient. This report describes the novel use of a tubular retractor for cervicomedullary decompression via transoral odontoidectomy for abscess drainage and phlegmon resection in a patient with progressive cervical myelopathy. The tubular retractor serves to retract the pharyngeal wall flaps and expose the anterior arch of C1, odontoid, and inferior clivus. This variation of the transoral approach eliminates the need for stay sutures for these purposes and may be used for lesions of the odontoid and anterior epidural space of the superior cervical spine.Open Access Article. UA Open Access Publishing Fund.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]