Dual-phase Cone-beam Computed Tomography to See, Reach, and Treat Hepatocellular Carcinoma during Drug-eluting Beads Transarterial Chemo-embolization

The advent of cone-beam computed tomography (CBCT) in the angiography suite has been revolutionary in interventional radiology. CBCT offers 3 ...

Philips Healthcare

Current methods for imaging joint motion are limited to either two-dimensional (2D) video fluoroscopy, or to animated motions from a series of static three-dimensional (3D) images. 3D movement patterns can be detected from biplane fluoroscopy images matched with computed tomography images. This involves several x-ray modalities and sophisticated 2D to 3D matching for the complex wrist joint. We present a method for the acquisition of dynamic 3D images of a moving joint. In our method a 3D-rotational x-ray (3D-RX) system is used to image a cyclically moving joint. The cyclic motion is synchronized to the x-ray acquisition to yield multiple sets of projection images, which are reconstructed to a series of time resolved 3D images, i.e., four-dimensional rotational x ray (4D-RX). To investigate the obtained image quality parameters the full width at half maximum (FWHM) of the point spread function (PSF) via the edge spread function and the contrast to noise ratio between air and phantom were determined on reconstructions of a bullet and rod phantom, using 4D-RX as well as stationary 3D-RX images. The CNR in volume reconstructions based on 251 projection images in the static situation and on 41 and 34 projection images of a moving phantom were 6.9, 3.0, and 2.9, respectively. The average FWHM of the PSF of these same images was, respectively, 1.1, 1.7, and 2.2 mm orthogonal to the motion and parallel to direction of motion 0.6, 0.7, and 1.0 mm. The main deterioration of 4D-RX images compared to 3D-RX images is due to the low number of projection images used and not to the motion of the object. Using 41 projection images seems the best setting for the current system. Experiments on a postmortem wrist show the feasibility of the method for imaging 3D dynamic joint motion. We expect that 4D-RX will pave the way to improved assessment of joint disorders by detection of 3D dynamic motion patterns in joints.

4D rotational x-ray imaging of wrist joint dynamic motion.

Recently, three-dimensional (3D) rotational x-ray imaging has been combined with navigation technology, enabling direct 3D navigation for minimally invasive image guided interventions. In this study, phantom experiments are used to determine the accuracy of such a navigation set-up for a mobile C-arm with propeller motion. After calibration of the C-arm system, the accuracy is evaluated by pinpointing divots on a special-purpose phantom with known geometry. This evaluation is performed both with and without C-arm motion in between calibration and registration for navigation. The variation caused by each of the individual transformations in the calibration and registration process is also studied. The feasibility of direct navigation on 3D rotational x-ray images for functional endoscopic sinus surgery has been evaluated in a cadaver navigation experiment. Navigation accuracy was approximately 1.0 mm, which is sufficient for functional endoscopic sinus surgery. C-arm motion in between calibration and registration slightly degraded the registration accuracy by approximately 0.3 mm. Standard deviations of each of the transformations were in the range 0.15-0.31 mm. In the cadaver experiment, the navigation images were considered in good correspondence with the endoscopic images by an experienced ENT surgeon. Availability of 3D localization information provided by the navigation system was considered valuable by the ENT surgeon.

Direct navigation on 3D rotational x-ray data acquired with a mobile propeller C-arm: accuracy and application in functional endoscopic sinus surgery.

To review the postoperative radiographic investigations of patients implanted with a cochlear implant.

Migration of the ball electrode after cochlear implantation.

We present a method for measurement dynamic in vivo carpal motion patterns. The method consists of a 4-D rotational X-ray (RX) with improved image quality and image processing for accurate detection in vivo wrist motion measurements. Dynamic 3-D imaging yields a number of volume reconstructions of the wrist at different phases of its cyclic motion. Next, the carpal reconstructions are registered to their static acquired and segmented counterpart in all phases. With this information, the relation between the applied motion and carpal kinematic behavior is acquired, i.e., the motion patterns. We investigated the precision of the image acquisition and processing and tested it on three healthy subjects. The precision of the image acquisition and image processing is in the range of submillimeters and subdegrees, respectively, which is better than existing systems and sufficient for clinical investigations. Reproducibility measurements show some more deviation ( > 1 degrees). This method was tested on four human volunteers and agrees for the greater part with previously done invasive and nondynamic measurements. In vivo motion pattern measurement with 4-D-RX imaging and processing is accurate and noninvasive. The motion patterns can reveal disorders that could not have been detected in either video fluoroscopy, computed tomography, or MRI.

Detection of in vivo dynamic 3-D motion patterns in the wrist joint.

The optimal positioning of electrode arrays in the cochlea is extremely important. Our standard approach is to use a 3-dimensional rotational x-ray for the intraoperative determination of the position of the electrode array. We wanted to see if spread of excitation (SOE) is useful for determining the electrode array position within the cochlea.

Spread of excitation measurements for the detection of electrode array foldovers: a prospective study comparing 3-dimensional rotational x-ray and intraoperative spread of excitation measurements.

With the use of conventional C-arm fluoroscopy for hand surgery, suboptimal positioning of implants, K-wires, insufficient reconstructions and joint incongruities frequently remain unrevealed We prospectively compared the performance of the surgeon interpreted from conventional methods (2D fluoroscopy and direct visual and physical inspection) versus 3D imaging as well as the occurrence of revision surgeries based on post-op radiological findings. Twenty-four intraoperative findings based on 2D fluoroscopy and findings on direct visual and physical inspections were compared with intraoperatively acquired 3D-RX scans by means of a questionnaire. Moreover, record was kept of revision surgery (minimal three months follow up) for all patients treated with the aid of 3D-RX. A clear difference in findings was observed between the performance based on fluoroscopy and direct visual and physical inspection and that based on intraoperative 3D-RX for hand surgery (p < 0.05). Post-operative radiological examinations revealed that none of the 56 patients treated with the aid of 3D-RX needed revision surgery. Intraoperative 3D-RX provides information for the hand surgeon that is additional to the information acquired with conventional fluoroscopy. Intraoperative 3D-RX provides well defined images of the positioning of osteosynthesis material, of the spatial orientation of carpals, and of reconstruction of the wrist joint.

First experiences with the use of intraoperative 3D-RX for wrist surgery.

To describe a novel technique for multimodality positron emission tomography (PET) fusion-guided interventions that combines cone-beam computed tomography (CT) with PET/CT before the procedure.

Cone-beam computed tomography fusion and navigation for real-time positron emission tomography-guided biopsies and ablations: a feasibility study.

To measure and compare individual staff radiation dose levels during interventional radiologic (IR) procedures with and without real-time feedback to evaluate whether it has any impact on staff radiation dose.

Bart Carelsen

Interventional X-ray

Philips Healthcare

Dual-phase Cone-beam Computed Tomography to See, Reach, and Treat Hepatocellular Carcinoma during Drug-eluting Beads Transarterial Chemo-embolization

Bart Carelsen

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Philips Healthcare

Dual-phase Cone-beam Computed Tomography to See, Reach, and Treat Hepatocellular Carcinoma during Drug-eluting Beads Transarterial Chemo-embolization

Interventional X-ray