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Gene therapy is an exciting frontier in medicine today. Radiologists will be involved in tracking the effects of these new therapies through imaging. Vascular and interventional radiology techniques also are ideally suited for minimally invasive, readily monitored gene delivery. Gene therapy is accomplished through gene augmentation or gene blocking. The latter is accomplished through antisense oligonucleotides or transcription factor decoys. Vectors are agents that facilitate gene delivery and expression and can be viral or nonviral. The vascular wall is an ideal target for gene therapy because of its central role in many biologic processes and its ready accessibility. Recombinant genes can be delivered ex vivo and in vivo, with the latter approaches involving open surgical, percutaneous injection, and endovascular catheter-based methods. Perforated, hydrogel-coated, and double balloon catheters have been used with varying success. Optimal catheter systems for gene transfer will enable delivery of the vector to the precise anatomic location with transfection limited to the cells of interest and will minimize shedding of the vector to distal sites, systemic effects of the therapeutic agent, and morbidity from the delivery method. Radiologists must become familiar with the basic rationale, strategies, and mechanisms of gene therapy and involved in its clinical trials to ensure an active role in this field.

Aortic or brachiocephalic vessel injuries secondary to blunt thoracic trauma are relatively common and can occur throughout the length of the thoracic aorta or in various locations in the brachiocephalic vessels. Aortography remains the standard of reference for the diagnosis of these injuries despite recent technologic advances in other imaging modalities. The classic aortographic finding in aortic or brachiocephalic vessel injury consists of a large false aneurysm, typically protruding from the medial aspect of the aortic isthmus. However, intrathoracic aortic or brachiocephalic vessel injury can and does occur at any intrathoracic location and may exhibit a wide variety of radiographic appearances, thereby presenting a diagnostic challenge even for experienced trauma angiographers. Large false aneurysms may appear oval or rounded, tubular, or asymmetrically globular and may manifest in unusual locations such as the ascending aorta. Although smaller, irregularly shaped false aneurysms at atypical locations may be obscure or mimic ductus diverticula, their irregular, sharp margins allow them to be distinguished as injuries. The subtlety of aortic or brachiocephalic vessel injuries necessitates a high degree of suspicion along with meticulous imaging technique in all cases and the use of additional projections in equivocal cases for definitive diagnosis.

Laceration of the thoracic aorta or brachiocephalic vessels due to blunt trauma is relatively common. In such cases, prompt and accurate diagnosis followed by timely surgery is essential. These injuries typically occur at the aortic isthmus and can usually be readily identified at aortography, which remains the standard of reference for diagnosis. However, numerous anatomic variants that manifest as "lumps" or "bumps" on aortograms can mimic true vascular injury, thereby leading to false-positive or false-negative diagnosis. These variants include aortic spindle, classic or atypical ductal diverticula, and infundibula of the brachiocephalic arteries and adjacent branches or of the right third intercostal artery. Ductus diverticula typically occur at the isthmus and have smooth, uninterrupted margins with gently sloping shoulders. Infundibula are also smoothly marginated but can occur in a variety of locations and generally taper into one or more vessels at their apex. Knowledge of the imaging appearances of these anatomic variants is necessary for correct interpretation of aortograms of the aorta and brachiocephalic vessels in blunt trauma patients.