[Computed tomography guidance: fluoroscopy and more].

Although ultrasound and magnetic resonance imaging are competitive imaging modalities for the guidance of needle-based interventions, computed tomography (CT) is the only modality suitable for image-guided interventions in all regions of the body, including the lungs and bone. The ongoing technical development of CT involves accelerated image acquisition, significantly improved spatial resolution, CT scanners with an extended gantry diameter, acceleration of the procedure through joystick control of relevant functions of interventional CT by the interventional radiologist and tube current modulation to protect the hands of the examiner and radiosensitive organs of the patient. CT fluoroscopy can be used as a real-time method (the intervention is monitored under continuous CT fluoroscopy) or as a quick check method (repeated acquisitions of individual CT fluoroscopic images after each change of needle or table position). For the two approaches, multislice CT fluoroscopy (MSCTF) technique with wide detectors is particularly useful because even in the case of needle deviation from the center slice the needle tip is simultaneously visualised in the neighboring slices. With the aid of this technique a precise placement of interventional devices is possible even in angled access routes and in the presence of pronounced respiratory organ movements. As the reduction of CT fluoroscopy time significantly reduces radiation exposure for the patient and staff, the combination of a quick check technique and a low milliampere technique with multislice CT fluoroscopy devices is advantageous.