Donald F. Schomer

Percutaneous vertebroplasty and kyphoplasty for painful vertebral body fractures in cancer patients

Object The current North American experience with minimally invasive vertebro- and kyphoplasty is largely limited to the treatment of benign osteoporotic compression fractures. The objective of this study was to assess the safety and efficacy of these procedures for painful vertebral body (VB) fractures in cancer patients. Methods The authors reviewed a consecutive group of cancer patients (21 with myeloma and 35 with other primary malignancies) undergoing vertebro- and kyphoplasty at their institution. Ninety-seven (65 vertebro- and 32 kyphoplasty) procedures were performed in 56 patients during 58 treatment sessions. The mean patient age was 62 years (+/- 13 years [standard deviation]) and the median duration of symptoms was 3.2 months. All patients suffered intractable spinal pain secondary to VB fractures. Patients noted marked or complete pain relief after 49 procedures (84%), and no change after five procedures (9%); early postoperative Visual Analog Scale (VAS) pain scores were unavailable in four patients (7%). No patient was worse after treatment. Reductions in VAS pain scores remained significant up to 1 year (p = 0.02, Wilcoxon signed-rank test). Analgesic consumption was reduced at 1 month (p = 0.03, Wilcoxon signed-rank test). Median follow-up length was 4.5 months (range 1 day-19.7 months). Asymptomatic cement leakage occurred during vertebroplasty at six (9.2%) of 65 levels; no cement extravasation was seen during kyphoplasty. There were no deaths or complications related to the procedures. The mean percentage of restored VB height by kyphoplasty was 42 +/- 21%. Conclusions Percutaneous vertebro- and kyphoplasty provided significant pain relief in a high percentage of patients, and this appeared durable over time. The absence of cement leakage-related complications may reflect the use of 1) high-viscosity cement; 2) kyphoplasty in selected cases; and 3) relatively small volume injection. Precise indications for these techniques are evolving; however, they are safe and feasible in well-selected patients with refractory spinal pain due to myeloma bone disease or metastases.

The anatomy of the posterior communicating artery as a risk factor for ischemic cerebral infarction.

BACKGROUND After the occlusion of an internal carotid artery the principal source of collateral flow is through the arteries of the circle of Willis, but the size and patency of these arteries are quite variable. Study of the anatomy of the collateral pathways in patients with internal-carotid-artery occlusion with or without infarction in the watershed area of the deep white matter may identify patterns that afford protection from ischemic infarction. METHODS Using conventional magnetic resonance imaging and three-dimensional phase-contrast magnetic resonance angiography, we evaluated 29 consecutive patients (32 hemispheres at risk) with angiographically proved occlusion of the internal carotid artery. Four collateral pathways to the occluded vessel were evaluated: the proximal segment of the anterior cerebral artery, the posterior communicating artery, the ophthalmic artery, and leptomeningeal collateral vessels from the posterior cerebral artery. RESULTS Only features of the ipsilateral posterior communicating artery were related to the risk of watershed infarction. The presence of posterior communicating arteries measuring at least 1 mm in diameter was associated with the absence of watershed infarction (13 hemispheres, no infarcts; P < 0.001). Conversely, there were 4 watershed infarcts in the 6 hemispheres with posterior communicating arteries measuring less than 1 mm in diameter and 10 infarcts in the 13 hemispheres with no detectable flow in the ipsilateral posterior communicating artery. CONCLUSIONS A small (< 1 mm in diameter) or absent ipsilateral posterior communicating artery is a risk factor for ischemic cerebral infarction in patients with internal-carotid-artery occlusion.

GLIOMATOSIS CEREBRI: IMPROVED OUTCOME WITH RADIOTHERAPY

PURPOSE Gliomatosis cerebri is a rare, diffuse involvement of the central nervous system by a malignant glioma that permeates the brain extensively without destroying the neural architecture and involves more than two lobes. In this study, we sought to assess the role of radiotherapy (RT) and identify prognostic factors in gliomatosis cerebri. METHODS AND MATERIALS Thirty patients who received RT at a single institution and had radiographic follow-up were retrospectively reviewed with respect to outcome, radiation parameters, extent of surgery, and chemotherapy. All cases were analyzed histologically and documented. All pathology slides and radiology images were reviewed. RESULTS The median age at diagnosis was 38.6 years (range 16-68). The median follow-up was 12.8 months (range 3-110). The mean radiation dose was 54.9 Gy, given in a mean of 28 fractions. Radiographic improvement or disease stabilization was achieved in 87% of patients. Clinical improvement was observed in 70%. The median time to progression was 10 months, and it was significantly longer for patients <40 years old (p = 0.0007) and for patients having a tumor histologic subtype other than glioblastoma (p = 0.01). The median overall survival was 18 months and was also longer for patients <40 years (p = 0.0001) and for patients having nonglioblastoma histologic features (p = 0.007). Extensive surgery, administration of chemotherapy, or increased RT volume improved neither overall survival nor the time to disease progression. CONCLUSION RT is effective against gliomatosis cerebri. Patients who are young and have a nonglioblastoma tumor histologic subtype perform more favorably. In this analysis, no role for chemotherapy, extensive surgery, or whole-brain RT was found.

A review of MRI pulse sequences and techniques in neuroimaging

BACKGROUND The unmatched soft tissue contrast provided by magnetic resonance imaging (MRI) has made it the modality of choice for many neuroimaging examinations. The fact that signal intensity in MRI depends on many parameters, including spin-lattice and spin-spin relaxation times, proton density, and velocity, makes it possible to highlight various pathologies by appropriate choice of pulse sequences and pulse sequence parameters. It is somewhat overwhelming however, to filter through various pulse sequences and parameters in order to understand how their selection affects image contrast. This brief review is intended to highlight common pulse sequences and parameters as well as introduce new techniques currently being released for clinical use. MATERIALS Basic pulse sequences are described and the influence of the acquisition parameters on image contrast are illustrated. Such basic sequences include the ubiquitous spin echo, fast spin echo, and gradient echo sequences. Specialized techniques for fat suppression and magnetic resonance angiography are also presented. Currently approved contrast agents for use in MRI are briefly reviewed, and various advanced pulse sequences, such as those for diffusion and magnetization transfer contrast imaging, are briefly outlined. RESULTS The utility of basic and advanced pulse sequences are demonstrated by clinical examples and images of normal brain and spine. New sequences and techniques are briefly outlined with regard to their potential for improving neuroimaging examinations. CONCLUSIONS This brief review outlines how the choice of pulse sequence and acquisition parameters influences the resulting image contrast for a variety of basic and advanced imaging techniques.

The Joint Commission Practice Performance Evaluation: A Primer for Radiologists

As health care quality continues to move into the limelight, so do physicians. The new Joint Commission requirements (Ongoing Professional Practice Evaluation and Focused Professional Practice Evaluation) mandate continuous data-based evaluation and monitoring of physician practice performance. This task could be seen as cumbersome, but it may provide opportunities to develop quality improvement programs that demonstrate the value provided by hospital-based radiologists.

Continuous Quality Improvement Programs Provide New Opportunities to Drive Value Innovation Initiatives in Hospital-Based Radiology Practices

Imaging services constitute a huge portion of the of the total dollar investment within the health care enterprise. Accordingly, this generates competition among medical specialties organized along service lines for their pieces of the pie and increased scrutiny from third-party payers and government regulators. These market and political forces create challenge and opportunity for a hospital-based radiology practice. Clearly, change that creates or builds greater value for patients also creates sustainable competitive advantage for a radiology practice. The somewhat amorphous concept of quality constitutes a significant value driver for innovation in this scenario. Quality initiatives and programs seek to define and manage this amorphous concept and provide tools for a radiology practice to create or build more value. Leadership and the early adoption of these inevitable programs by a radiology practice strengthens relationships with hospital partners and slows the attrition of imaging service lines to competitors.

Progressive Multifocal Leukoencephalopathy with Concurrent Richter's Syndrome

Progressive multifocal leukoencephalopathy (PML) is a demyelinating infectious disease caused by the JC virus. It was originally described in patients with chronic lymphocytic leukemia (CLL). Richters syndrome, or transformation to large cell lymphoma, occurs in approximately 3% of patients with CLL, and carries a poor prognosis. We report a patient with documented PML and concurrent Richters transformation outside the central nervous system. Before establishing a definitive diagnosis of PML, radiation therapy to the presumed lymphomatous brain lesion had been considered, raising the issue of whether stereotactic brain biopsy should be considered in every patient in a similar situation. Although this is likely a rare occurrence, patients with Richters transformation documented at an extra-neural site and a brain lesion may benefit from the establishment of an infectious diagnosis which would influence therapy.

Analysis of radiology business models

As health care moves to value orientation, radiologys traditional business model faces challenges to adapt. The authors describe a strategic value framework that radiology practices can use to best position themselves in their environments. This simplified construct encourages practices to define their dominant value propositions. There are 3 main value propositions that form a conceptual triangle, whose vertices represent the low-cost provider, the product leader, and the customer intimacy models. Each vertex has been a valid market position, but each demands specific capabilities and trade-offs. The underlying concepts help practices select value propositions they can successfully deliver in their competitive environments.

Performance analysis of a new semiorthogonal spline wavelet compression algorithm for tonal medical images.

Lossy image compression is thought to be a necessity as radiology moves toward a filmless environment. Compression algorithms based on the discrete cosine transform (DCT) are limited due to the infinite support of the cosine basis function. Wavelets, basis functions that have compact or nearly compact support, are mathematically better suited for decorrelating medical image data. A lossy compression algorithm based on semiorthogonal cubic spline wavelets has been implemented and tested on six different image modalities (magnetic resonance, x-ray computed tomography, single photon emission tomography, digital fluoroscopy, computed radiography, and ultrasound). The fidelity of the reconstructed wavelet images was compared to images compressed with a DCT algorithm for compression ratios of up to 40:1. The wavelet algorithm was found to have generally lower average error metrics and higher peak-signal-to-noise ratios than the DCT algorithm.

Monte Carlo Simulation to Analyze the Cost-Benefit of Radioactive Seed Localization Versus Wire Localization for Breast-Conserving Surgery in Fee-for-Service Health Care Systems Compared With Accountable Care Organizations

OBJECTIVE In breast-conserving surgery for nonpalpable breast cancers, surgical reexcision rates are lower with radioactive seed localization (RSL) than wire localization. We evaluated the cost-benefit of switching from wire localization to RSL in two competing payment systems: a fee-for-service (FFS) system and a bundled payment system, which is typical for accountable care organizations. MATERIALS AND METHODS A Monte Carlo simulation was developed to compare the cost-benefit of RSL and wire localization. Equipment utilization, procedural workflows, and regulatory overhead differentiate the cost between RSL and wire localization. To define a distribution of possible cost scenarios, the simulation randomly varied cost drivers within fixed ranges determined by hospital data, published literature, and expert input. Each scenario was replicated 1000 times using the pseudorandom number generator within Microsoft Excel, and results were analyzed for convergence. RESULTS In a bundled payment system, RSL reduced total health care cost per patient relative to wire localization by an average of