Osteosarcoma: review of the various types with emphasis on recent advancements in imaging.

Osteosarcoma is the classic malignant osteoid-forming bone tumor. The typical clinical presentation, histology, imaging findings, treatment, and prognosis for each subtype of osteosarcoma is provided. Particular emphasis is placed on more current magnetic resonance imaging and nuclear medicine imaging techniques that may soon improve the ability to determine the most appropriate therapy and ultimately improve patient survival.

Oral cavity and oropharyngeal squamous cell cancer: key imaging findings for staging and treatment planning.

The imaging findings in squamous cell carcinoma (SCC) of the oral cavity and oropharynx vary widely, depending on the site of origin of the primary tumor and the extent of its involvement of other regions. Knowledge of the complex anatomy of the oral cavity and oropharynx, as well as the most common routes by which SCC spreads from various anatomic sites, allows the radiologist to accurately determine the extent of disease and help clinicians plan appropriate treatment. SCCs that originate in the oral cavity tend to behave differently than those that originate in the oropharynx, with the latter group exhibiting more aggressive growth. Furthermore, primary tumors in certain anatomic subsites within the oral cavity or oropharynx have a greater propensity to spread by direct extension along muscle, bone, or neurovascular bundles or to be disseminated along lymphatic drainage pathways to regional or distant nodes. Imaging findings of deep muscular, neurovascular, osseous, or nodal involvement are indicative of an advanced stage of disease for which management options are limited.

A cruel twist: post-operative cecal volvulus.

Cecal volvulus is an uncommon cause of intestinal obstruction, accounting for less than 1% of cases in Western countries. In the literature, it has been described as a complication following numerous common surgeries as well as a number of minimally invasive procedures. Presumably, it is more likely to occur following any surgical procedure which might require some degree of medial visceral rotation or disruption of the fusion plane between the cecum or ascending colon with the lateral peritoneum, providing sufficient mobility to allow for cecal volvulization to occur. In addition, cadaver and autopsy studies have also suggested that 10-20% of the population may have sufficient mobility of the colon to allow for volvulization. We present a review of the literature pertaining to the diagnosis and management of cecal volvulus as well as the case of J.R., a 78-year-old male with cecal volvulus six days following a right radical nephrectomy for renal cell carcinoma.

Characterization of the relation between CT technical parameters and accuracy of quantification of lung attenuation on quantitative chest CT.

OBJECTIVE: The purpose of this study was to assess the compromise between CT technical parameters and the accuracy of CT quantification of lung attenuation. MATERIALS AND METHODS: Materials that simulate water (0 H), healthy lung (-650 H), borderline emphysematous lung (-820 H), and severely emphysematous lung (-1,000 H) were placed at both the base and the apex of the lung of an anthropomorphic phantom and outside the phantom. Transaxial CT images through the samples were obtained while the effective tube current was varied from 440 to 10 mAs, kilovoltage from 140 to 80 kVp, and slice thickness from 0.625 to 10 mm. Mean +/- SD attenuation within the samples and the standard quantitative chest CT measurements, the percentage of pixels with attenuation less than -910 H and 15th percentile of attenuation, were computed. RESULTS: Outside the phantom, variations in CT parameters produced less than 2.0% error in all measurements. Within the anthropomorphic phantom at 30 mAs, error in measurements was much larger, ranging from zero to 200%. Below approximately 80 mAs, mean attenuation became increasingly biased. The effects were most pronounced at the apex of the lungs. Mean attenuation of the borderline emphysematous sample of apex decreased 55 H as the tube current was decreased from 300 to 30 mAs. Both the 15th percentile of attenuation and percentage of pixels with less than -910 H attenuation were more sensitive to variations in effective tube current than was mean attenuation. For example, the -820 H sample should have 0% of pixels less than -910 H, which was true at 400 mA. At 30 mA in the lung apex, however, the measurement was highly inaccurate, 51% of pixels being below this value. Decreased kilovoltage and slice thickness had analogous, but lesser, effects. CONCLUSION: The accuracy of quantitative chest CT is determined by the CT acquisition parameters. There can be significant decreases in accuracy at less than 80 mAs for thin slices in an anthropomorphic phantom, the most pronounced effects occurring in the lung apex.

Perioperative evaluation in Herlyn-Werner-Wunderlich syndrome.

BACKGROUND: Herlyn-Werner-Wunderlich syndrome is defined by uterine didelphys, obstructed hemivagina, and ipsilateral renal agenesis. We report the presentation, radiographic findings, and outcomes of three patients with Herlyn-Werner-Wunderlich syndrome who underwent surgical management at a tertiary care academic medical center. CASES: Two patients were diagnosed by magnetic resonance imaging and one by ultrasonography. All three underwent successful transvaginal septoplasty and drainage of the hematocolpos and hematometra. One required septoplasty revision with temporary vaginal stent placement. CONCLUSION: Herlyn-Werner-Wunderlich syndrome is a rare condition. The most urgent concern is the obstruction of menstrual effluent. Unlike an isolated transverse vaginal septum, the vaginal septum with Herlyn-Werner-Wunderlich syndrome is parallel to the patent vaginal canal, less pliable, and closer to the cervix. These anatomical differences result in pronounced distortion with significant diagnostic and surgical challenges.

Adenosine nucleotides and the regulation of GRP94-client protein interactions.

The molecular chaperone heat shock protein 90 (Hsp90) serves essential roles in the regulation of signaling protein function, trafficking, and turnover. Hsp90 function is intimately linked to intrinsic ATP binding and hydrolysis activities, the latter of which is under the regulatory control of accessory factors. Glucose-regulated protein of 94 kDa (GRP94), the endoplasmic reticulum Hsp90, is highly homologous to cytosolic Hsp90. However, neither accessory factors nor adenosine nucleotides have been clearly implicated in the regulation of GRP94-client protein interactions. In the current study, the structural and regulatory consequences of adenosine nucleotide binding to GRP94 were investigated. We report that apo-GRP94 undergoes a time- and temperature-dependent tertiary conformational change that exposes a site(s) of protein-protein interaction; ATP, ADP, and radicicol markedly suppress this conformational change. In concert with these findings, ATP and ADP act identically to suppress GRP94 homooligomerization, as well as both local and global conformational activity. To identify a role(s) for ATP or ADP in the regulation of GRP94-client protein interactions, immunoglobulin (Ig) heavy chain folding intermediates containing bound GRP94 and immunoglobulin binding protein (BiP) were isolated from myeloma cells, and the effects of adenosine nucleotides on chaperone-Ig heavy chain interactions were examined. Whereas ATP elicited efficient release of BiP from both wild-type and mutant Ig heavy chain intermediates, GRP94 remained in stable association with Ig heavy chains in the presence of ATP or ADP. On the basis of these data, we propose that structural maturation of the client protein substrate, rather than ATP binding or hydrolysis, serves as the primary signal for dissociation of GRP94-client protein complexes.