Emergency radiologic evaluation of the pediatric cervical spine can be challenging because of the confusing appearance of synchondroses, normal anatomic variants, and injuries that are unique to children. Cervical spine injuries in children are usually seen in the upper cervical region owing to the unique biomechanics and anatomy of the pediatric cervical spine. Knowledge of the normal embryologic development and anatomy of the cervical spine is important to avoid mistaking synchondroses for fractures in the setting of trauma. Familiarity with anatomic variants is also important for correct image interpretation. These variants include pseudosubluxation, absence of cervical lordosis, wedging of the C3 vertebra, widening of the predental space, prevertebral soft-tissue widening, intervertebral widening, and "pseudo-Jefferson fracture." In addition, familiarity with mechanisms of injury and appropriate imaging modalities will aid in the correct interpretation of radiologic images of the pediatric cervical spine.

PurposeThe goal of this work was to develop phantoms for the optimization of pre‐operative computed tomography (CT) scans of the prostate artery, which are used for embolization planning.MethodsAcrylonitrile butadiene styrene (ABS) pellets were doped with barium sulfate and extruded into filaments suitable for 3D printing on a fused deposition modeling (FDM) printer. Cylinder phantoms were created to evaluate radiopacity as a function of doping percentage. Small‐diameter tree phantoms were created to assess their composition and dimensional accuracy. A half‐pelvis phantom was created using clinical CT images, to assess the printer's control over cortical bone thickness and cancellous bone attenuation. CT‐derived prostate artery phantoms were created to simulate complex, contrast‐filled arteries.ResultsA linear relationship (R = 0.998) was observed between barium sulfate added (0%–10% by weight), and radiopacity (−31 to 1454 Hounsfield Units [HU]). Micro‐CT scans showed even distribution of the particles, with air pockets comprising 0.36% by volume. The small vessels were found to be oversized by a consistent amount of 0.08 mm. Micro‐CT scans revealed that the phantoms' interiors were completely filled in. The maximum HU values of cortical bone in the phantom were lower than that of the filament, a result of CT image reconstruction. Creation of cancellous bone regions with lower HU values, using the printer's infill parameter, was successful. Direct volume renderings of the pelvis and prostate artery were similar to the clinical CT, with the exception that the surfaces of the phantom objects were not as smooth.ConclusionsIt is possible to reliably create FDM 3D printer filaments with predictable radiopacity in a wide range of attenuation values, which can be used to print dimensionally accurate radiopaque objects derived from CT data. Phantoms of this type can be quickly and inexpensively developed to assess and optimize CT protocols for specific clinical applications.

Transjugular intrahepatic portosystemic shunt has evolved into an important option for management of complications of portal hypertension. The use of polytetrafluoroethylene covered stents enhances shunt patency. Hepatic encephalopathy (HE) remains a significant problem after TIPS placement. The approach to management of patients with refractory hepatic encephalopathy typically requires collaboration between different specialties. Patient selection for TIPS requires careful evaluation of risk factors for HE. TIPS procedure-related technical factors like stent size, attention to portosystemic pressure gradient reduction and use of adjunctive variceal embolization maybe important. Conservative medical therapy in combination with endovascular therapies often results in resolution or substantial reduction of symptoms. Liver transplantation is, however, the ultimate treatment.

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