Cath-Finder Catheter Tracking System: a new device for positioning of central venous catheters. Early experience from implantation of brachial portal systems

Appropriateness of Replacing Fluoroscopic Guidance With ECG-Electromagnetic Guidance for PICC Insertion: A Randomized Controlled Trial

OBJECTIVE. Coupled ECG-electromagnetic (EM) guidance shows promise for use in placement of peripherally inserted central catheters (PICCs) when compared with the classic blind technique. However, ECG-EM guidance has not been appropriately compared with the reference standard of fluoroscopy (FX) guidance. Here, we aimed to compare ECG-EM guidance with FX guidance with regard to the final tip position of PICCs. SUBJECTS AND METHODS. A total of 120 patients (age range, 19-94 years) referred for PICC placement were randomized to the ECG-EM or FX group. All interventions were performed by PICC team members who had the same standardized training and experience. Final tip position was assessed using chest radiography and was classified as optimal, suboptimal, or inadequate requiring repositioning on the basis of the distance from the PICC tip to the cavoatrial junction (CAJ). Statistical analyses were performed using the Mann-Whitney U test for final catheter tip position (mean distance from CAJ) and Fisher and chi-square tests for proportions. RESULTS. PICCs were successfully inserted in 118 patients (53 men and 65 women). Catheter tip positions were optimal or suboptimal in 100% of the FX group and 77.2% of the ECG-EM group. Furthermore, precision of placement was significantly better (p = .004) in the FX group (mean distance from the PICC tip to the CAJ = 0.83 cm) than in the ECGEM group (mean distance from the PICC tip to the CAJ = 1.37 cm). Thirteen (22.8%) of the PICCs placed using ECG-EM guidance, all of which were inserted from the left side, were qualified as inadequate requiring repositioning and required another intervention. CONCLUSION. Our results revealed significant differences in final tip position between the ECG-EM and FX guidance techniques and indicate that ECG-EM guidance cannot appropriately replace FX guidance among unselected patients. However, ECGEM guidance could be considered as an acceptable technique for patients in whom the PICC could be inserted from the right side. TRIAL REGISTRATION. ClinicalTrials.gov NCT03652727.

An algorithm for tracking microcatheters in fluoroscopy

Currently, a large number of endovascular interventions are performed for treatment of intracranial aneurysms. For these treatments, correct positioning of microcatheter tips, microguide wire tips, or coils is essential. Techniques to detect such devices may facilitate endovascular interventions. In this paper, we describe an algorithm for tracking of microcatheter tips during fluoroscopically guided neuroendovascular interventions. A sequence of fluoroscopic images (1,024 x 1,024 x 12 bits) was acquired using a C-arm angiography system as a microcatheter was passed through a carotid phantom which was on top of a head phantom. The carotid phantom was a silicone cylinder containing a simulated vessel with the shape and curvatures of the internal carotid artery. The head phantom consisted of a human skull and tissue-equivalent material. To detect the microcatheter in a given fluoroscopic frame, a background image consisting of an average of the four previous frames is subtracted from the current frame, the resulting image is filtered using a matched filter, and the position of maximum intensity in the filtered image is taken as the catheter tip position in the current frame. The distance between the tracked position and the correct position (error distance) was measured in each of the fluoroscopic images. The mean and standard deviation of the error distance values were 0.277 mm (1.59 pixels) and 0.26 mm (1.5 pixels), respectively. The error distance was less than 3 pixels in the 93.0% frames. Although the algorithm intermittently failed to correctly detect the catheter, the algorithm recovered the catheter in subsequent frames.

Microcatheter tip enhancement in fluoroscopy: a comparison of techniques

We compared three techniques for enhancement of microcatheter tips in fluoroscopic images: conventional subtraction technique (CST); averaged image subtraction technique (AIST), which we have developed; and double average filtering (DAF) technique, which uses nonlinear background estimates. A pulsed fluoroscopic image sequence was obtained as a microcatheter was passed through a carotid phantom that was on top of a head phantom. The carotid phantom was a silicone cylinder containing a simulated vessel with the shape and curvatures of the internal carotid artery. The three techniques were applied to the images of the sequence, then the catheter tip was manually identified in each image, and 100 x 100 pixel images, centered at the indicated microcatheter tip positions, were extracted for the evaluations. The signal-to-noise ratio (SNR) was calculated in each of the extracted images from which the mean value of the SNR and its standard deviation (SD) were calculated for each technique. The mean values and the standard deviations were 4.36 (SD 3.40) for CST, 6.34 (SD 3.62) for AIST, and 3.55 (SD 1.27) for DAF. AIST had a higher SNR compared to CST in almost all frames. Although DAF yielded the smallest mean SNR value, it yielded the best SNR in those frames in which the microcatheter tip did not move between frames. We conclude that AIST provides the best SNR for a moving microcatheter tip and that DAF is optimal for a temporarily stationary microcatheter tip.

Accuracy of implanted port placement with the use of the electromagnetic CathTrack catheter locator system

PURPOSE

To test whether an electromagnetic guidance system such as CathTrack would allow long-term central venous access devices to be reliably placed at a decreased cost and without radiation exposure to patients and staff. The following study was undertaken to verify accuracy of the CathTrack system for catheter placement and to develop guidelines for its use.

METHODS

Twenty-nine consecutive patients were prospectively enrolled in the study and taken to the operating room for implantation of a permanent central venous access port. By protocol, the CathTrack system was used to guide initial catheter positioning using the center of the third intercostal space along the right sternal border as the desired external target. Fluoroscopy was then used to visualize tip position and relocate the catheter tip to the exact position desired by the surgeon.

RESULTS

Catheter placement using the CathTrack system was successfully accomplished in 27 out of 29 patients. In two instances CathTrack was abandoned and fluoroscopy utilized because of difficulty in threading the initial guidewire into the superior vena cava.

CONCLUSION

The CathTrack electromagnetic locator system can be used to reliably position catheters for the establishment of long-term central venous access. Decreased cost and elimination of radiation exposure are distinct advantages of this system over fluoroscopy.

Guide-wire tracking during endovascular interventions

A method is presented to extract and track the position of a guide wire during endovascular interventions under X-ray fluoroscopy. The method can be used to improve guide-wire visualization in low-quality fluoroscopic images and to estimate the position of the guide wire in world coordinates. A two-step procedure is utilized to track the guide wire in subsequent frames. First, a rough estimate of the displacement is obtained using a template-matching procedure. Subsequently, the position of the guide wire is determined by fitting a spline to a feature image. The feature images that have been considered enhance line-like structures on: 1) the original images; 2) subtraction images; and 3) preprocessed images in which coherent structures are enhanced. In the optimization step, the influence of the scale at which the feature is calculated and the additional value of using directional information is investigated. The method is evaluated on 267 frames from ten clinical image sequences. Using the automatic method, the guide wire could be tracked in 96% of the frames, with a similar accuracy to three observers, although the position of the tip was estimated less accurately.

Comparison of vascular access devices

OBJECTIVE

To provide an overview of venous access device designs and methods of insertion and removal.

CONCLUSIONS

Venous access devices are indicated for many patients who require reliable long-term venous access. Three types of venous access devices are available including nontunneled, tunneled, and implanted ports. Since their introduction into clinical practice, the widespread use of these devices has had an enormous impact on cancer treatment by decreasing the overuse of peripheral veins while allowing for more flexibility and choice of the type of device used. Although numerous devices are available, each offers unique designs and performance expectations. Each type of device has similar features and can be used for intravenous drug and nutritional therapy, administration of blood products, and withdrawal of blood.

IMPLICATIONS FOR NURSING PRACTICE

Even if only a single device is used in a given setting, the nurse must have a basic understanding of all types of venous access devices. It is imperative that the nurse be fully cognizant of the anatomic position and structure of the major vessels associated with the central venous system, especially for the insertion of peripheral central catheters. Understanding the venous system and venous access design can assist in preventing or assessing potential complications.

Central venous brachial catheter (P.A.S. Port TM) and catheter scanning system (Cath-Finder TM)

To assess the effectiveness and safety of an implanted portal with a central venous brachial implanted catheter, P.A.S. Port TM(P-P), and the accuracy of its Cath Finder TM tracking system (C-F), (Pharmacia Deltec) vs. radiology, a phase II multicentric study was designed. The catheter was implanted in 53 oncologic patients treated with chemotherapy and the performance of the catheter was evaluated for 3 months. No problems arose during the implantation in 77% of the cases and in all cases radiologic location of the catheter tip coincided with the C-F. We can conclude that P-P is easy to implant and to maintain in the arm and that it is well tolerated by the patients. C-F is an accurate and reliable system for locating the catheter tip. The use of both systems is an attractive alternative to the standard ones.