Informatics in radiology (infoRAD): introduction to the language of three-dimensional imaging with multidetector CT.

The recent proliferation of multi-detector row computed tomography (CT) has led to an increase in the creation and interpretation of images in planes other than the traditional axial plane. Powerful three-dimensional (3D) applications improve the utility of detailed CT data but also create confusion among radiologists, technologists, and referring clinicians when trying to describe a particular method or type of image. Designing examination protocols that optimize data quality and radiation dose to the patient requires familiarity with the concepts of beam collimation and section collimation as they apply to multi-detector row CT. A basic understanding of the time-limited nature of projection data and the need for thin-section axial reconstruction for 3D applications is necessary to use the available data effectively in clinical practice. The axial reconstruction data can be used to create nonaxial two-dimensional images by means of multiplanar reformation. Multiplanar images can be thickened into slabs with projectional techniques such as average, maximum, and minimum intensity projection; ray sum; and volume rendering. By assigning a full spectrum of opacity values and applying color to the tissue classification system, volume rendering provides a robust and versatile data set for advanced imaging applications.

Percutaneous radiofrequency ablation of hepatic tumors against the diaphragm: frequency of diaphragmatic injury.

PURPOSE: To retrospectively determine the frequency of diaphragmatic injury when percutaneous hepatic radiofrequency (RF) ablation is performed adjacent to the diaphragm. MATERIALS AND METHODS: Institutional Review Board approval was obtained for our HIPAA-compliant study. Informed consent for the ablation procedure and for use of related data for future research was obtained from each patient. A retrospective review was conducted of 215 patients undergoing percutaneous RF ablation of hepatic tumors. Twenty-nine patients (21 men and eight women; age, 41-89 years) were identified with tumors abutting the diaphragm. Episodes of right shoulder pain were recorded. A panel of radiologists blinded to the patients' clinical histories reviewed their imaging for evidence of diaphragmatic injury and ablation success. A generalized estimating equation model and the Fisher exact test were used for statistical analysis. RESULTS: The 29 patients had a total of 33 tumors abutting the diaphragm. Tumor size was 1.3-5.5 cm (mean, 3.2 cm +/- 1.1). After ablation, five (17%) patients reported right shoulder pain. In four, pain was mild or moderate, with symptoms lasting 2-14 days (median, 5.5 days). Three of these showed diaphragmatic thickening on postablation computed tomographic (CT) scans. One patient had severe pain lasting 2 weeks, followed by milder pain for 2 months. This patient's postablation CT images showed focal nodular diaphragmatic thickening. This patient was treated with a multitined device; the other four, with straight-needle devices. Local tumor progression was seen in 14 tumors (42.4%). Tumors 3 cm or smaller had a much lower local progression rate than tumors larger than 3 cm (12.5% vs 70.6%). CONCLUSION: Of 29 patients who had ablation of hepatic tumors adjacent to the diaphragm, five (17%) had diaphragmatic injury, which was clinically apparent with right shoulder pain.

Digital radiography for the field: a portable prototype.

The US military has been investigating methods for improving radiographic support for field medical operations. The purpose of this project was to develop and test a portable digital radiography (DR) system to determine its feasibility for field operations. A prototype portable digital radiography device was designed and assembled using a commercially available DR sensor. The sensor and necessary hardware were mounted into a ruggedized aluminum case. The device underwent testing in the hospital and field environments. The prototype rapidly provided digital radiographs in a variety of settings. Shortcomings of the device affecting usability and reliable operation were identified. The successful construction and operation of a portable digital radiography prototype shows that such a device is feasible for field applications. The prototype requires further modification and testing to improve its usability and reliability, and to explore other potential applications, both military and civilian.