Role of Advanced MR Imaging in Diagnosis of Neurological Malignancies: Current Status and Future Perspective.

Lesions of the central nervous system (CNS) can present with numerous and overlapping radiographical and clinical features that make diagnosis difficult based exclusively on history, physical examination, and traditional imaging modalities. Given that there are significant differences in optimal treatment protocols for these various CNS lesions, rapid and non-invasive diagnosis could lead to improved patient care. Recently, various advanced magnetic resonance imaging (MRI) techniques showed promising methods to differentiate between various tumors and lesions that conventional MRI cannot define by comparing their physiologic characteristics, such as vascularity, permeability, oxygenation, and metabolism. These advanced MRI techniques include dynamic susceptibility contrast MRI (DSC), diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) MRI, Golden-Angle Radial Sparse Parallel imaging (GRASP), Blood oxygen level-dependent functional MRI (BOLD fMRI), and arterial spin labeling (ASL) MRI. In this article, a narrative review is used to discuss the current trends in advanced MRI techniques and potential future applications in identifying difficult-to-distinguish CNS lesions. Advanced MRI techniques were found to be promising non-invasive modalities to differentiate between paraganglioma, schwannoma, and meningioma. They are also considered promising methods to differentiate gliomas from lymphoma, post-radiation changes, pseudoprogression, demyelination, and metastasis. Advanced MRI techniques allow clinicians to take advantage of intrinsic biological differences in CNS lesions to better identify the etiology of these lesions, potentially leading to more effective patient care and a decrease in unnecessary invasive procedures. More clinical studies with larger sample sizes should be encouraged to assess the significance of each advanced MRI technique and the specificity and sensitivity of each radiologic parameter.

Autoimmune diseases of the spine and spinal cord.

Magnetic resonance imaging (MRI) and clinicopathological tools have led to the identification of a wide spectrum of autoimmune entities that involve the spine. A clearer understanding of the unique imaging features of these disorders, along with their clinical presentations, will prove invaluable to clinicians and potentially limit the need for more invasive procedures such as tissue biopsies. Here, we review various autoimmune diseases affecting the spine and highlight salient imaging features that distinguish them radiologically from other disease entities.

Magnetic resonance imaging-derived relative cerebral blood volume characteristics in a case of pathologically confirmed neurocysticercosis: illustrative case.

BACKGROUND: Neurocysticercosis (NCC) is a parasitic infection of the brain caused by ingesting water or food contaminated with tapeworm eggs. When it presents as a solitary mass, differentiation from a primary brain tumor on imaging can be difficult. Magnetic resonance imaging (MRI)-derived relative cerebral blood volume (rCBV) is a newer imaging technique used to identify areas of neovascularization in tumors, which may advance the differential diagnosis. OBSERVATIONS: A 25-year-old male presented after a seizure. Computed tomography (CT) and MRI demonstrated a partially enhancing lesion with microcalcifications and vasogenic edema. Follow-up rCBV assessment demonstrated mild hyperperfusion and/or small vessels at the lesional margins consistent with either an intermediate grade glioma or infection. Given the radiological equipoise, surgical accessibility, and differential diagnosis including primary neoplasm, metastatic disease, NCC, and abscess, resection was pursued. The calcified mass was excised en bloc and was confirmed as larval-stage NCC. LESSONS: CT or MRI may not always provide sufficient information to distinguish NCC from brain tumors. Although reports have suggested that rCBV may aid in identifying NCC, here the authors describe a case of pathologically confirmed NCC in which preoperative, qualitative, standardized rCBV findings raised concern for a primary neoplasm. This case documents the first standardized rCBV values reported in a pathologically confirmed case of NCC in the United States.

Is portable ultrasonography accurate in the evaluation of Schanz pin placement during extremity fracture fixation in austere environments?

OBJECTIVE: The purpose of this study was to investigate the efficacy of ultrasonography to confirm Schanz pin placement in a cadaveric model, and the interobserver repeatability of the ultrasound methodology. DESIGN: This investigation is a repeated measures cadaveric study with multiple examiners. PARTICIPANTS: Cadaveric preparation and observations were done by an orthopaedic traumatologist and resident, and two general surgery traumatologists. INTERVENTIONS: A total of 16 Schanz pins were equally placed in bilateral femora and tibiae. Four examiners took measurements of pin protrusion beyond the distal cortices using first ultrasonography and then by direct measurement after gross dissection. MAIN OUTCOME MEASURE(S): Distal Schanz pin protrusion length measurements from both ultrasonography and direct measurement post dissection. RESULTS: Schanz pin protrusion measurements are underestimated by ultrasonography (p < 0.01) by an average of 10 percent over the range of 5 to 18 mm, and they display a proportional bias that increases the under reporting as the magnitude of pin protrusion increases. Ultrasound data demonstrate good linear correlation and closely represent actual protrusion values in the 5 to 12 mm range. Interobserver repeatability analysis demonstrated that all examiners were not statistically different in their measurements despite minimal familiarity with the ultrasound methodology (p > 0.8). CONCLUSIONS: Despite the statistical imparity of pin protrusion measurement via ultrasound compared to that of gross dissection, a consideration of the clinical relevance of ultrasound measurement bias during an austere operating theatre leads to the conclusion that ultrasonography is an adequate methodology for Schanz pin protrusion measurement.

Review of periprosthetic osteolysis in total joint arthroplasty: an emphasis on host factors and future directions.

Periprosthetic osteolysis is one of the leading causes of total joint revision procedures. If allowed to progress in the absence of radiographic diagnosis and/or proper medical treatment, osteolysis may result in aseptic loosening yielding failure of the implant and the need for complex revision arthroplasty. The purpose of this review was to assess the current understanding of periprosthetic osteolysis with an emphasis on host factors and future directions. A PubMed search was conducted using the following key words; osteolysis, periprosthetic osteolysis, osteolysis imaging. Pertinent articles, as it pertained to the outline of the review, were selected. Periprosthetic osteolysis stems from numerous risk factors. Osteolysis host characteristic risk factors include gender, body weight, and genetics. Current implant designs have reduced the incidence of this disease; however no current design has been able to replicate the in vivo characteristics and therefore development of wear particles continues to be seen. Advanced methods of imaging diagnosis are on the rise, however early imaging diagnosis is currently ineffective. Pharmacologic intervention appears to be a logical avenue for medical intervention, but no approved drug therapy to prevent or inhibit periprosthetic osteolysis is currently available. Although the rate of periprosthetic osteolysis seems to be decreasing with advances in implant design and increased knowledge of the biological process of wear particle induced osteolysis, the rapid increase in the total number of total joint arthroplasties over the next two decades means that better ways of detecting and treating periprosthetic osteolysis are greatly needed.

Percutaneous acetabuloplasty: a cadaveric study.

Periacetabular osteolysis is a common etiology of prosthesis failure in patients who undergo total hip arthroplasty. These lesions are treated by open and, more recently, percutaneous techniques. The purpose of this study was to determine the relevant surface anatomy and bony landmarks in establishing percutaneous access to periacetabular regions and identifying critical at-risk structures in establishing access. Percutaneous access to the periacetabular region was established superiorly, anteroinferiorly, and posteroinferiorly by using 5 L5-to-mid thigh fixed cadaver pelvises with latex-injected vessels using threaded guidewires. Dissection was completed to identify structures at risk, with the distance from the wires recorded to the nearest millimeter. C-arm position for the optimal visualization and placement of guidewires was recorded. Average distance from the pin and the at-risk structures ranged from 11.2 to 38.7 mm. All 3 approaches allowed for safe percutaneous access to the periacetabular regions without injuring significant anatomical structures. This study established safe starting points and orientation for guidewires and radiograph projections associated with percutaneous access to the periacetabular regions. The findings in this study will be useful for developing minimally invasive approaches to these regions for the treatment of osteolytic lesions of diverse etiology. However, a biomechanical evaluation of the impact of these bony channels on the strength of pelvis under physiological and unanticipated loading must be performed before this technique can be safely translated to clinical practice.

Predictive measures of a resident's performance on written Orthopaedic Board scores.

OBJECTIVE: Residency programs are continually attempting to predict the performance of both current and potential residents. Previous studies have supported the use of USMLE Steps 1 and 2 as predictors of Orthopaedic In-Training Examination (OITE) and eventual American Board of Orthopaedic Surgery success, while others show no significant correlation. A strong performance on OITE examinations does correlate with strong residency performance, and some believe OITE scores are good predictors of future written board success. The current study was designed to examine potential differences in resident assessment measures and their predictive value for written boards. DESIGN/METHODS: A retrospective review of resident performance data was performed for the past 10 years. Personalized information was removed by the residency coordinator. USMLE Step 1, USMLE Step 2, Orthopaedic In-Training Examination (from first to fifth years of training), and written orthopaedic specialty board scores were collected. Subsequently, the residents were separated into two groups, those scoring above the 35(th) percentile on written boards and those scoring below. Data were analyzed using correlation and regression analyses to compare and contrast the scores across all tests. RESULTS: A significant difference was seen between the groups in regard to USMLE scores for both Step 1 and 2. Also, a significant difference was found between OITE scores for both the second and fifth years. Positive correlations were found for USMLE Step 1, Step 2, OITE 2 and OITE 5 when compared to performance on written boards. One resident initially failed written boards, but passed on the second attempt This resident consistently scored in the 20(th) and 30(th) percentiles on the in-training examinations. CONCLUSIONS: USMLE Step 1 and 2 scores along with OITE scores are helpful in gauging an orthopaedic resident's performance on written boards. Lower USMLE scores along with consistently low OITE scores likely identify residents at risk of failing their written boards. Close monitoring of the annual OITE scores is recommended and may be useful to identify struggling residents. Future work involving multiple institutions is warranted and would ensure applicability of our findings to other orthopedic residency programs.

Synthesis, characterization, and structure of cyclopenta[c]thiophenes and their manganese complexes.

1,3-Diaryl-4H-cyclopenta[c]thiophenes are efficiently prepared from 1,2-diaroylcyclopentadienes by use of Lawesson's reagent. eta5-Cyclopenta[c]thienyl complexes, [Mn(eta5-SC7H3-1,3-R2)(CO)3] (R = Me, Ph), are prepared in high yield by ligand substitution reactions of [MnBr(CO)5] with [SnMe3(SC7H3-1,3-R2)]. Alternatively, thiation with P4S10/NaHCO3 converts [Mn{eta5-1,2-C5H3(COR)2)(CO)3] to [Mn(eta5-SC7H3-1,3-R2)(CO)3] (R = Ph, 4-tolyl, 4-MeOC6H4, benzo[2,3-b]thienyl). The molecular structures of complexes with R = Me, Ph show planar eta5-cyclopenta[c]thienyl ligands, with the manganese atom slightly displaced away from the ring-fusion bond.