How to Incorporate Dual-Energy Computed Tomography Into Your Neuroradiology Practice: Questions and Answers.

Dual-energy computed tomography (DECT) has many current and evolving applications in neuroradiology including material decomposition, improving conspicuity of iodinated contrast enhancement, and artifact reduction. However, there are multiple challenges in incorporating DECT into practice including hardware selection, postprocessing software requirements, technologist and physician training, and numerous workflow issues. This article reviews in a question-and-answer format common issues that arise when incorporating DECT into a busy neuroradiology practice.

Arthroscopic Excision of Acetabular Osteoid Osteoma: Computer Tomography-Guided Approach.

Osteoid osteoma is a benign osteoblastic tumor that occurs in the subcortical shaft and metaphysis of the long bones of the lower extremities; however, intra-articular lesions are also possible. Intra-articular osteoid osteomas are rare, and clinical symptoms are often less specific and, thereby, may lead to misdiagnosis. The definitive treatment for osteoid osteoma is the excision of the nidus. We present the case of a 23-year-old man with a 4-year history of right anterior hip pain, subsequently diagnosed with a subarticular osteoid osteoma located in the right anterior acetabulum. Hip arthroscopic excision of the juxta-articular osteoid osteoma is presented as an effective treatment, with the advantage of less potential damage to normal bone and cartilage, as well as the additional benefits available with hip arthroscopy.

Arthroscopic treatment of slipped capital femoral epiphysis screw impingement and concomitant hip pathology.

Impingement caused by screws used for stabilization of slipped capital femoral epiphysis can be treated arthroscopically. Although troublesome screws have traditionally been removed by open techniques, arthroscopic removal can successfully be achieved. In addition to affording the patient the benefits of minimally invasive surgery, surgeons also have the ability to arthroscopically address any concomitant hip pathology responsible for pain, including femoroacetabular impingement and labral tears.

In vitro detection of drug-induced phospholipidosis using gene expression and fluorescent phospholipid based methodologies.

Phospholipidosis (PLD) is characterized by the excessive intracellular accumulation of phospholipids. It is well established that a large number of cationic amphiphilic drugs have the potential to induce PLD. In the present study, we describe two facile in vitro methods to determine the PLD-inducing potential of a molecule. The first approach is based on a recent study by (Sawada et al., 2005, Toxicol. Sci. 83, 282-292) in which 17 genes were identified as potential biomarkers of PLD in HepG2 cells. To confirm the utility of this gene panel, we treated HepG2 cells with PLD-positive and -negative compounds and then analyzed gene expression using real-time PCR. Our initial analysis, which used a single dose of each drug, correctly identified five of eight positive compounds and four of four negative compounds. We then increased the doses of the three false negatives (amiodarone, tamoxifen, and loratadine) and found that the changes in gene expression became large enough to correctly identify them as PLD-inducing drugs. Our results suggest that a range of concentrations should be used to increase the accuracy of prediction in this assay. Our second approach utilized a fluorescently labeled phospholipid (LipidTox) which was added to the media of growing HepG2 cells along with compounds positive and negative for PLD. Phospholipid accumulation was determined using confocal microscopy and, more quantitatively, using a 96-well plate assay and a fluorescent plate reader. Using an expanded set of compounds, we show that this assay correctly identified 100% of PLD-positive and -negative compounds. Dose-dependent increases in intracellular fluorescent phospholipid accumulation were observed. We found that this assay was less time consuming, more sensitive, and higher throughput than gene expression analysis. To our knowledge, this study represents the first validation of the use of LipidTox in identifying drugs that can induce PLD.