C-arm cone beam computed tomographic needle path overlay for fluoroscopic-guided placement of translumbar central venous catheters

Cone-beam computed tomography-assisted percutaneous gastrostomy tube insertion in children with challenging anatomy

BACKGROUND

Percutaneous radiological gastrostomy tube insertion is a common procedure in children. An approach using ultrasound and fluoroscopy may not be feasible in patients with challenging anatomy; therefore, advanced techniques or other imaging modalities may be required.

OBJECTIVE

To describe our experience using cone-beam computed tomography (CT)-assisted percutaneous gastrostomy insertion in pediatric patients with challenging anatomy.

MATERIALS AND METHODS

A retrospective review was performed in children who underwent cone-beam CT-assisted percutaneous radiologic gastrostomy between January 2015 and July 2019. Indications, technique, outcomes, complications, and radiation dose (reference-point air kerma, air kerma area product) were assessed through chart and imaging review. Descriptive statistics only were used.

RESULTS

Twenty-seven procedures were attempted in 26 patients. Reasons for utilizing cone-beam CT guidance were high-positioned stomach (n = 10), interposing bowel loops and liver (n = 19), omphalocele (n = 1), severe scoliosis (n = 1), and ventriculoperitoneal shunt (n = 1). Technical success was 85% (23/27). Mean procedure time was 96 min (range 50-131 min). No safe access route into the stomach was encountered in four patients; three were referred for surgical gastrostomy and one had a successful re-attempt. Radiation dose data was obtained from 19 procedures (17 successful) with a total dose in successful procedures ranging from 8.1 to 63.6 mGy (average 26.2 mGy, median 24.9 mGy). The number of cone-beam CT acquisitions per procedure ranged from 1 to 4. Major complication frequency was 11% (3/27) (bleeding, peritonitis, and aspiration pneumonia); minor complication frequency was 3.7% (1/27).

CONCLUSION

This study shows that cone-beam CT guidance can be useful for assisting percutaneous radiologic gastrostomy in children with challenging anatomy.

Real-time three-dimensional fluoroscopy-navigated percutaneous pelvic screw placement for fragility fractures of the pelvis in the hybrid operating room

BACKGROUND

The prognosis of conservative treatment for fragility fracture of the pelvis (FFP) in the older patients remains poor. Percutaneous pelvic screw placement (PPSP), which aids in the treatment of FFP, can be challenging to perform using fluoroscopy alone because of the proximity of blood vessels and neuroforamina. Hence, this study aimed to investigate the accuracy and clinical outcomes of PPSP using real-time 3D fluoroscopic navigation for FFP in the hybrid operating room.

METHODS

This study included 41 patients with FFP who underwent PPSP in a hybrid operating room between April 2016 and December 2020. Intraoperative C-arm cone-beam CT was performed under general anesthesia. Guidewire trajectory was planned using a needle guidance system. The guidewire was inserted along the overlaid trajectory using 3D fluoroscopic navigation, and a 6.5 mm cannulated cancellous screw (CCS) was placed. The clinical outcomes and accuracy of the screw placement were then investigated.

RESULTS

A total of 121 screws were placed. The mean operative time was 84 ± 38.7 minutes, and the mean blood loss was 7.6 ± 3.8 g. The mean time to wheelchair transfer was 2 days postoperatively. Pain was relieved in 35 patients. Gait ability from preoperative and latest follow-up after surgery was maintained in 30 (73%) patients. All 41 patients achieved bone union. Of the 121 screws, 119 were grade 0 with no misplacement; only 2 patients had grade 1 perforations.

CONCLUSION

PPSP using real-time 3D fluoroscopic navigation in a hybrid operating room was accurate and useful for early mobilization and pain relief among older patients with FFP with an already-installed needle biopsy application.

Central venous access port placement by translumbar approach using angio-CT unit in patients with superior vena cava syndrome

PURPOSE

To evaluate the clinical results of central venous access port (CV port) placement by translumbar inferior vena cava cannulation using angio-CT unit for cancer patients with superior vena cava syndrome.

MATERIALS AND METHODS

A CV port was placed by translumbar inferior vena cava cannulation using an angio-CT unit, in 14 consecutive patients. All patients had occlusion or advanced stenosis of the superior vena cava due to cancer progression.

RESULTS

The technical success rate of the percutaneous translumbar CV port placement was 100%. The only complication related to port placement was bleeding in the right iliopsoas muscle seen on CT in one patient, but it stopped with conservative treatment. The mean initial device service interval was 125 days (range 6-448 days). Complications in the chronic phase occurred in two patients, one with catheter-related infection and the other with catheter breakage, for a rate of 0.44/1000 catheter days. In the patient with the broken catheter, the port chamber placement site was cut and replaced with a new catheter by guidewire exchange.

CONCLUSIONS

CV port placement with translumbar inferior vena cava cannulation using an angio-CT unit for cancer patients with superior vena cava syndrome was safe and effective.

Cone beam computed tomography and its image guidance technology during percutaneous nucleoplasty procedures at L5/S1 lumbar level

OBJECTIVE

To demonstrate the feasibility of percutaneous nucleoplasty procedures at L5/S1 level using cone beam CT (CBCT) and its associated image guidance technology for the treatment of lumbar disc herniation (LDH).

MATERIALS AND METHODS

We retrospectively reviewed 25 cases (20 men, 5 women) of LDH at L5/S1 levels. CBCT as guidance imaging was chosen after a first unsuccessful fluoroscopy attempt that was related to complex anatomy (n = 15), rapid pathological changes due to degenerative diseases (n = 7) or both (n = 3). Technical success, defined as correct needle positioning in the target LDH, and safety were evaluated; overall procedure time and radiation dose were registered. A visual analog scale (VAS) was used to evaluate pain and discomfort pre-intervention after 1 week and 1, 3, and 6 months after the procedure.

RESULTS

Technical success was 100 %; using CBCT as guidance imaging the needle was correctly positioned at the first attempt in 20 out of 25 patients. Neither major nor minor complications were registered during or after the procedure. The average procedure time was 11 min and 56 s (range, 9-15 min), whereas mean procedural radiation dose was 46.25 Gy.cm² (range 38.10-52.84 Gy.cm²), and mean fluoroscopy time was 5 min 34 s (range 3 min 40 s to 6 min 55 s). The VAS pain score decreased significantly from 7.6 preoperatively to 3.9 at 1 week, 2.8 at 1 month, 2.1 at 3 months, and 1.6 at 6 months postoperatively.

CONCLUSIONS

CBCT-guided percutaneous nucleoplasty is a highly effective technique for LDH with acceptable procedure time and radiation dose.

Multimodality fusion imaging in abdominal and pelvic malignancies: current applications and future perspectives

Medicine is evolving toward personalized care and this development entails the integration, amalgamation, and synchronized analysis of data from multiple sources. Multimodality fusion imaging refers to the simultaneous visualization of spatially aligned and juxtaposed medical images obtained by two or more image modalities. PET/MRI scanners and MMFI platforms are able to improve the diagnostic workflow in oncologic patients and provide exquisite images that aid physicians in the molecular profiling and characterization of tissues. Advanced navigation platforms involving real-time ultrasound are promising tools for guiding personalized and tailored mini-invasive interventional procedures on technically challenging targets. The main objective of the present essay was to describe the current applications and future perspectives of multimodality fusion imaging for both diagnostic and interventional purposes in the field of abdominal and pelvic malignancies. We also outlined the technical differences between fusion imaging achieved by means of simultaneous bimodal acquisition (i.e., integrated PET/MRI scanners), retrospective co-registration, and multimodality fusion imaging involving ultrafast or real-time imaging modalities.

Radiation exposure of abdominal cone beam computed tomography

PURPOSE

To evaluate patients radiation exposure of abdominal C-arm cone beam computed tomography (CBCT).

METHODS

This prospective study was approved by the institutional review board; written, informed consent was waived. Radiation exposure of abdominal CBCT was evaluated in 40 patients who underwent CBCT during endovascular interventions. Dose area product (DAP) of CBCT was documented and effective dose (ED) was estimated based on organ doses using dedicated Monte Carlo simulation software with consideration of X-ray field location and patients' individual body weight and height. Weight-dependent ED per DAP conversion factors were calculated. CBCT radiation dose was compared to radiation dose of procedural fluoroscopy. CBCT dose-related risk for cancer was assessed.

RESULTS

Mean ED of abdominal CBCT was 4.3 mSv (95 % confidence interval [CI] 3.9; 4.8 mSv, range 1.1-7.4 mSv). ED was significantly higher in the upper than in the lower abdomen (p = 0.003) and increased with patients' weight (r = 0.55, slope = 0.045 mSv/kg, p < 0.001). Radiation exposure of CBCT corresponded to the radiation exposure of on average 7.2 fluoroscopy minutes (95 % CI 5.5; 8.8 min) in the same region of interest. Lifetime risk of exposure related cancer death was 0.033 % or less depending on age and weight.

CONCLUSIONS

Mean ED of abdominal CBCT was 4.3 mSv depending on X-ray field location and body weight.

C-arm Cone Beam Computed Tomography: A New Tool in the Interventional Suite

Introduction: C-arm Cone Beam CT (CBCT) is a technology that is being integrated into many of the newer angiography systems in the interventional suite. Due to its ability to provide cross sectional imaging, it has opened a myriad of opportunities for creating new clinical applications. We review the technical aspects, current reported clinical applications and potential benefits of this technology. Materials and Methods: Searches were made via PubMed using the string “CBCT”, “Cone Beam CT”, “Cone Beam Computed Tomography” and “C-arm Cone Beam Computed Tomography”. All relevant articles in the results were reviewed. Results: CBCT clinical applications have been reported in both vascular and non-vascular interventions. They encompass many aspects of a procedure including preprocedural planning, intraprocedural guidance and postprocedural assessment. As a result, they have allowed the interventionalist to be safer and more accurate in performing image guided procedures. There are however several technical limitations. The quality of images produced is not comparable to conventional computed tomography (CT). Radiation doses are also difficult to quantify when compared to CT and fluoroscopy. Conclusion: CBCT technology in the interventional suite has contributed significant benefits to the patient despite its current limitations. It is a tool that will evolve and potentially become an integral part of imaging guidance for intervention. Key words: Angiogram, Biopsy, Embolisation, Intervention, Stenting, Vascular

Image fusion during vascular and nonvascular image-guided procedures

Image fusion may be useful in any procedure where previous imaging such as positron emission tomography, magnetic resonance imaging, or contrast-enhanced computed tomography (CT) defines information that is referenced to the procedural imaging, to the needle or catheter, or to an ultrasound transducer. Fusion of prior and intraoperative imaging provides real-time feedback on tumor location or margin, metabolic activity, device location, or vessel location. Multimodality image fusion in interventional radiology was initially introduced for biopsies and ablations, especially for lesions only seen on arterial phase CT, magnetic resonance imaging, or positron emission tomography/CT but has more recently been applied to other vascular and nonvascular procedures. Two different types of platforms are commonly used for image fusion and navigation: (1) electromagnetic tracking and (2) cone-beam CT. Both technologies would be reviewed as well as their strengths and weaknesses, indications, when to use one vs the other, tips and guidance to streamline use, and early evidence defining clinical benefits of these rapidly evolving, commercially available and emerging techniques.

Cone beam CT guidance provides superior accuracy for complex needle paths compared with CT guidance

OBJECTIVE

To determine the accuracy of cone beam CT (CBCT) guidance and CT guidance in reaching small targets in relation to needle path complexity in a phantom.

METHODS

CBCT guidance combines three-dimensional CBCT imaging with fluoroscopy overlay and needle planning software to provide real-time needle guidance. The accuracy of needle positioning, quantified as deviation from a target, was assessed for inplane, angulated and double angulated needle paths. Four interventional radiologists reached four targets along the three paths using CBCT and CT guidance. Accuracies were compared between CBCT and CT for each needle path and between the three approaches within both modalities. The effect of user experience in CBCT guidance was also assessed.

RESULTS

Accuracies for CBCT were significantly better than CT for the double angulated needle path (2.2 vs 6.7 mm, p<0.001) for all radiologists. CBCT guidance showed no significant differences between the three approaches. For CT, deviations increased with increasing needle path complexity from 3.3 mm for the inplane placements to 4.4 mm (p=0.007) and 6.7 mm (p<0.001) for the angulated and double angulated CT-guided needle placements, respectively. For double angulated needle paths, experienced CBCT users showed consistently higher accuracies than trained users [1.8 mm (range 1.2-2.2) vs 3.3 mm (range 2.1-7.2) deviation from target, respectively; p=0.003].

CONCLUSION

In terms of accuracy, CBCT is the preferred modality, irrespective of the level of user experience, for more difficult guidance procedures requiring double angulated needle paths as in oncological interventions.

ADVANCES IN KNOWLEDGE

Accuracy of CBCT guidance has not been discussed before. CBCT guidance allows accurate needle placement irrespective of needle path complexity. For angulated and double-angulated needle paths, CBCT is more accurate than CT guidance.

Efficacy of DynaCT for surgical navigation during complex laparoscopic surgery: an initial experience

BACKGROUND

Precise understanding of surgical anatomy is required during complex laparoscopic surgery (CLS). The purpose of this study was to present our initial operative experience with CLS facilitated by surgical navigation through DynaCT technology.

METHODS

Intraoperative computed tomography (CT) images of two CLS cases were obtained by a C-arm DynaCT system (Artis Zeego, Siemens Healthcare, Erlangen, Germany). Image reconstruction was performed on a workstation to define particular anatomical structures of the target tumor. The reconstructed CT images were repeatedly displayed on a submonitor. The surgeon then compared the CT images with a laparoscopic image of the surgical field, thus providing a virtual map to the surgeon.

RESULTS

Using the near-real-time surgical navigation system, the surgeon could visualize the surgical anatomy and easily perform the CLS. All procedures were performed successfully with a satisfactory diagnostic yield.

CONCLUSION

This novel technology has great potential for application in CLS because it enables generation of accurate depictions of small target tumors and increases the surgeon's confidence during the procedure.

Multimodality image fusion-guided procedures: technique, accuracy, and applications

Personalized therapies play an increasingly critical role in cancer care: Image guidance with multimodality image fusion facilitates the targeting of specific tissue for tissue characterization and plays a role in drug discovery and optimization of tailored therapies. Positron-emission tomography (PET), magnetic resonance imaging (MRI), and contrast-enhanced computed tomography (CT) may offer additional information not otherwise available to the operator during minimally invasive image-guided procedures, such as biopsy and ablation. With use of multimodality image fusion for image-guided interventions, navigation with advanced modalities does not require the physical presence of the PET, MRI, or CT imaging system. Several commercially available methods of image-fusion and device navigation are reviewed along with an explanation of common tracking hardware and software. An overview of current clinical applications for multimodality navigation is provided.

Laparoscopic radical nephrectomy under near real-time three-dimensional surgical navigation with C-arm cone beam computed tomography

OBJECTIVE

The aim of this study was to demonstrate the advantages of C-arm cone beam computed tomography for imaging guidance of laparoscopic radical nephrectomy (LRN).

METHODS

Four patients referred to the authors' institution for LRN were included in this study. To visualize the renal vascular anatomy, the Iopamiron 300 contrast agent was injected intravenously. The surgeon could adjust the viewing angle of the images and rotate the reconstructed three-dimensional (3D) image manually by using a mouse-like controller. Using the near real-time 3D navigation images, the surgeon was able to recognize the renal vascular anatomy, and more easily perform the LRN.

RESULTS

All procedures were successfully performed with a satisfactory diagnostic yield or therapeutic effect without procedure-related complications.

CONCLUSION

This novel technology has great potential for application in LRN because it enables accurate depiction of the renal vessels and increases surgeon confidence.

Interventional spinal procedures guided and controlled by a 3D rotational angiographic unit

OBJECTIVE

The aim of this paper is to demonstrate the usefulness of 2D multiplanar reformatting images (MPR) obtained from rotational acquisitions with cone-beam computed tomography technology during percutaneous extra-vascular spinal procedures performed in the angiography suite.

METHODS

We used a 3D rotational angiographic unit with a flat panel detector. MPR images were obtained from a rotational acquisition of 8 s (240 images at 30 fps), tube rotation of 180° and after post-processing of 5 s by a local work-station. Multislice CT (MSCT) is the best guidance system for spinal approaches permitting direct tomographic visualization of each spinal structure. Many operators, however, are trained with fluoroscopy, it is less expensive, allows real-time guidance, and in many centers the angiography suite is more frequently available for percutaneous procedures. We present our 6-year experience in fluoroscopy-guided spinal procedures, which were performed under different conditions using MPR images. We illustrate cases of vertebroplasty, epidural injections, selective foraminal nerve root block, facet block, percutaneous treatment of disc herniation and spine biopsy, all performed with the help of MPR images for guidance and control in the event of difficult or anatomically complex access.

RESULTS AND CONCLUSION

The integrated use of "CT-like" MPR images allows the execution of spinal procedures under fluoroscopy guidance alone in all cases of dorso-lumbar access, with evident limitation of risks and complications, and without need for recourse to MSCT guidance, thus eliminating CT-room time (often bearing high diagnostic charges), and avoiding organizational problems for procedures that need, for example, combined use of a C-arm in the CT room.

C-arm cone-beam CT-guided percutaneous transthoracic lung biopsy: usefulness in evaluation of small pulmonary nodules

OBJECTIVE

The purpose of this study was to evaluate the usefulness of C-arm conebeam CT-guided percutaneous transthoracic lung biopsy of small (≤ 2 cm) lung nodules.

MATERIALS AND METHODS

Twenty-seven patients who underwent C-arm cone-beam CT-guided percutaneous transthoracic lung biopsy of small (≤ 2 cm) lung nodules were enrolled in the study. The mean nodule size was 13 ± 4 mm in diameter. These lesions were divided into two groups according to size: 10 lesions 1 cm or smaller and 17 lesions larger than 1 cm. The diagnostic accuracy, sensitivity, and specificity in the two groups were compared by use of Fisher's exact test. Radiation dose in a female humanoid phantom was measured with radiophotoluminescent glass dosimeters. The average patient dose was calculated.

RESULTS

Eighteen malignant (67%) and eight benign (30%) nodules and one (3%) indeterminate nodule were found. The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 94%, 89%, 94%, 89%, and 92%. The sensitivity, specificity, and accuracy were 100%, 75%, and 90% for the lesions 1 cm or smaller and 91%, 100%, and 94% for the lesions larger than 1 cm. The accuracy, sensitivity, and specificity did not differ significantly between the groups (all p > 0.05, Fisher's exact test). The average radiation dose among 27 patients was 4.6 mSv (range, 2.19-9.37).

CONCLUSION

C-arm cone-beam CT-guided percutaneous transthoracic lung biopsy is a useful diagnostic technique in the evaluation of small lung nodules.

Electromagnetic navigation for thoracic aortic stent-graft deployment: a pilot study in swine

PURPOSE

To determine the feasibility of electromagnetic tracking as a method to augment conventional imaging guidance for the safe delivery, precise positioning, and accurate deployment of thoracic aortic endografts.

MATERIALS AND METHODS

Custom guide wires were fabricated, and the delivery catheters for thoracic aortic endoprostheses were retrofitted with integrated electromagnetic coil sensors to enable real-time endovascular tracking. Preprocedure thoracic computed tomographic (CT) angiograms were obtained after the placement of fiducial skin patches on the chest wall of three anesthetized swine, enabling automatic registration. The stent-graft deployment location target near the subclavian artery was selected on the preprocedure CT angiogram. Two steps were analyzed: advancing a tracked glidewire to the aortic arch and positioning the tracked stent-graft assembly by using electromagnetic guidance alone. Multiple CT scans were obtained to evaluate the accuracy of the electromagnetic tracking system by measuring the target registration error, which compared the actual position of the tracked devices to the displayed "virtual" electromagnetic-tracked position. Postdeployment CT angiography and necropsy helped confirm stent-graft position and subclavian artery patency.

RESULTS

A stent-graft was successfully delivered and deployed in each of the three animals by using real-time electromagnetic tracking alone. The mean fiducial registration error with autoregistration was 1.5 mm. Sixteen comparative scans were obtained to determine the target registration error, which was 4.3 mm +/- 0.97 (range, 3.0-6.0 mm) for the glidewire sensor coil. The mean target registration error for the stent-graft delivery catheter sensor coil was 2.6 mm +/- 0.7 (range, 1.9-3.8 mm). The mean deployment error for the stent-graft, defined as deployment deviation from the target, was 2.6 mm +/- 3.0.

CONCLUSIONS

Delivery and deployment of customized thoracic stent-grafts with use of electromagnetic tracking alone is feasible and accurate in swine. Combining endovascular electromagnetic tracking with conventional fluoroscopy may further improve accuracy and be a more realistic multimodality approach.

C-arm cone beam CT for hepatic tumor ablation under real-time 3D imaging

OBJECTIVE

We describe our experience with the application of a novel technology in which fluoroscopy and 3D imaging from C-arm cone beam CT systems are combined with integrated navigation software.

CONCLUSION

We applied this technology to five cases in which radiofrequency ablation was performed for hepatocellular carcinoma. Technical success was achieved without treatment-related complications in all cases. We conclude that this novel technology is potentially useful for targeting hepatic lesions.

C-arm cone beam computed tomography needle path overlay for fluoroscopic guided vertebroplasty

STUDY DESIGN

Retrospective review.

OBJECTIVE

To report our early clinical experience using C-arm cone beam computed tomography (C-arm CBCT) with fluoroscopic overlay for needle guidance during vertebroplasty.

SUMMARY OF BACKGROUND DATA

C-arm CBCT is advanced three-dimensional (3-D) imaging technology that is currently available on state-of-the-art flat panel based angiography systems. The imaging information provided by C-arm CBCT allows for the acquisition and reconstruction of "CT-like" images in flat panel based angiography/interventional suites. As part of the evolution of this technology, enhancements allowing the overlay of cross-sectional imaging information can now be integrated with real time fluoroscopy. We report our early clinical experience with C-arm CBCT with fluoroscopic overlay for needle guidance during vertebroplasty.

METHODS

This is a retrospective review of 10 consecutive oncology patients who underwent vertebroplasty of 13 vertebral levels using C-arm CBCT with fluoroscopic overlay for needle guidance from November 2007 to December 2008. Procedural data including vertebral level, approach (transpedicular vs. extrapedicular), access (bilateral vs. unilateral) and complications were recorded. Technical success with the overlay technology was assessed based on accuracy which consisted of 4 measured parameters: distance from target to needle tip, distance from planned path to needle tip, distance from midline to needle tip, and distance from the anterior 1/3 of the vertebral body to needle tip. Success within each parameter required that the distance between the needle tip and parameter being evaluated be no more than 5 mm on multiplanar CBCT or fluoroscopy.

RESULTS

Imaging data for 12 vertebral levels was available for review. All vertebral levels were treated using unilateral access and 9 levels were treated with an extrapedicular approach. Technical success rates were 92% for both distance from planned path and distance from midline to final needle tip, 100% when distance from needle tip to the anterior 1/3 border of the vertebral body was measured, and 75% when distance from target to needle tip was measured. There were no major complications. Minor complications consisted of 3 cases (25%) of cement extravasation.

CONCLUSION

C-arm CBCT with needle path overlay for fluoroscopic guided vertebroplasty is feasible and allows for reliable unilateral therapy of both lumbar and thoracic vertebral bodies. Extrapedicular approaches were performed safely and with good accuracy of reaching the targets.