Accuracy Of Catheter Placement Research Articles

Cardiac Conduction System: Anatomic Landmarks Relevant to Interventional Electrophysiologic Techniques Demonstrated with 64-Detector CT

The rapid development of clinical cardiac electrophysiology has triggered a renewed interest in the anatomy of the heart. A thorough knowledge of cardiac anatomy is a prerequisite for successful electrophysiologic procedures. Accurate description of the cardiac anatomy requires the use of a common language in describing this anatomy, as well as close interaction between radiologists, cardiologists, and surgeons. Given its capacity to provide relevant anatomic information in exquisite detail, multidetector computed tomography (CT) has the potential to allow faster and more accurate placement of intracardiac ablation catheters and pacemaker leads relative to the anatomy of interest. High-resolution reformatted images from 64-detector CT data provide accurate anatomic information for locating important landmarks relative to the cardiac conduction system or to current electrophysiologic interventions and cardiac resynchronization therapy.

Accurate placement of cerebrospinal fluid shunt ventricular catheters with real-time ultrasound guidance in older children without patent fontanelles

The authors present a technique in which real-time ultrasound monitoring is used to aid the insertion of cerebrospinal fluid (CSF) shunt ventricular catheters in children without patent fontanelles. Experience with the technique is reviewed. Intraoperative ultrasound is used to identify the compartments of the lateral ventricles and the choroid plexus prior to catheter insertion. Distance and trajectory to the best location for the hole-bearing segment of the catheter are determined and the catheter is inserted while real-time ultrasound monitoring is performed. Ten pediatric patients without open fontanelles underwent CSF shunt placement with the aid of transcranial ultrasound guidance between July and December 2006. After enlarging an occipital or frontal bur hole to a diameter of 2 cm to accommodate a small-footprint ultrasound probe, a ventricular catheter was carefully advanced into the frontal or occipital horn of the lateral ventricle while continuous ultrasound monitoring was performed. All catheters were inserted with a single pass through the brain. The final position of the ventricular catheter was visualized using intraoperative ultrasound. Postoperative computed tomography scans revealed all ventricular catheters placed accurately into the intended compartment of the ventricular system (for example, frontal horn or trigone). No procedure-related complications were noted. Real-time transcranial ultrasound monitoring through an enlarged bur hole is a feasible, safe, and effective technique for the placement of ventricular catheters in pediatric patients without a patent fontanelle.

VENTRICULAR CATHETER PLACEMENT WITH A FRAMELESS NEURONAVIGATIONAL SYSTEM

Accurate placement of ventricular catheters decreases the incidence of proximal catheter failure. The use of a frameless, interactive neuronavigational system can optimize catheter placement. Thirty-four ventricular catheters were placed using a Medtronic electromagnetic frameless neuronavigational system (Medtronic Navigation, Inc., Louisville, CO) during a 12-month period. The patients ranged in age from 11 months to 79 years; the mean age was 40.8 years. Nineteen male and 12 female patients participated in the study. The indications for ventricular catheter placement included obstructive hydrocephalus, normal pressure hydrocephalus, pseudotumor cerebri, intrathecal therapy, and tumor cyst aspiration. No proximal failures have been reported to date. One infection necessitated shunt removal. Three postoperative deaths occurred because of non-catheter-related events. Frameless neuronavigation in the placement of ventricular catheters assures accurate catheter placement, thereby decreasing the incidence of proximal catheter failure. The absence of rigid head fixation allows additional cohorts to benefit from the apparatus. The use of the electromagnetic system provides a safe, simple, and easy adjunct to optimal catheter placement.

Perineural Infusion of Local Anesthetics

Perineural Infusion of Local Anesthetics

Endoscopic placement of flatus tube using "lasso" technique with snare wire

A 55-year old man presented with acute sigmoid volvulus. The distal level of obstruction was above the level which could be reached by the rigid sigmoidoscope to allow decompression, and so a flatus tube was "lassoed" onto the side of a flexible endoscope which allowed accurate placement under direct vision. This technique allows accurate placement of catheters, feeding tubes and other devices endoscopically, which cannot be placed through the instrument channel of the endoscope.

PII: S0090-3019(05)00196-5

Ommaya reservoirs are used for administration of intrathecal chemotherapy and cerebrospinal fluid sampling. Ventricular catheter placement for these purposes requires a high degree of accuracy. Various options exist to optimize catheter placement. We analyze a cohort of patients receiving catheters using 2 different technologies.Retrospective chart review was performed on patients undergoing Ommaya reservoir placement between 2011 and 2014. Most procedures were assisted by either frameless stereotactic neuronavigation or fluoroscopic guidance with pneumoencephalogram. Catheter accuracy, revision rates, perioperative complications, and operative time were measured. Preoperative similarities and differences in diagnosis, demographics, and ventricular size were also recorded to avoid a biased assessment of our results.One-hundred and forty-five patients were included, 57 using fluoroscopic guidance and 88 using frameless stereotaxy. Common diagnoses in both groups were lymphoma and leptomeningeal disease. Qualitative measures of catheter placement accuracy showed no significant difference between the 2 groups. Proximity to the foramen of Monro favored fluoroscopy by a small margin (8.6 mm vs. 10.2 mm, P = 0.03). Overall revision rates were not significantly different between the groups (3.5% vs. 4.5%, P = 1.00). Early surgical complications occurred in 6.8% of the frameless stereotaxy group and 1.8% of the fluoroscopy group (P = 0.25).Ommaya reservoirs can be placed accurately using different methods. Although there are slight differences between fluoroscopy and frameless stereotaxy in quantitative accuracy and procedure time, there is no significant advantage of 1 method over the other when evaluating revision or complication rates. Technique familiarity and surgeon preference may dictate the preferred procedure.

Ventricular catheter placement in children with hydrocephalus and small ventricles: the use of a frameless neuronavigation system.

Accurate placement of ventricular catheters in children with small ventricles can be difficult. Too often, shunt catheters are misplaced with regard to optimal position and trajectory. The objective of this study was to determine whether neuronavigation-guided free-hand placement of ventricular catheters is an effective adjunct for children with hydrocephalus and small ventricles. Nine children with hydrocephalus (ages 1-12 years) participated in this study. Four children were diagnosed as suffering from slit ventricle syndrome and 5 children had small to mildly dilated ventricles. Of the 9 shunted children, 6 underwent previous shunt placements, and 1 child previously underwent an endoscopic third ventriculostomy. In 8 children the primary procedure was insertion of ventricular catheters using a frameless neuronavigation system. In 1 child, the neuronavigation system was used after failure to insert the ventricular catheter using a standard technique. All children showed significant improvement of their symptoms and signs following the procedure and none of them required shunt revision during the follow up period (mean 8+/-5 months). The usage of a neuronavigation system is safe and may be beneficial for optimal positioning and trajectory of ventricular catheters in children with small ventricles or an abnormal ventricular anatomy.

High dose rate brachytherapy boost treatment in radical radiotherapy for prostate cancer

The natural history of prostate cancer is for early invasion of the prostatic capsule and seminal vesicles. This will be present in the majority of patients presenting with a prostate specific antigen (PSA) >10 or Gleason score >7. In these patients a combination of external beam treatment to provide a regional dose of radiation followed by a high dose rate afterloading brachytherapy boost to enable conformal dose escalation within the prostate gland presents an attractive option in local treatment. Accurate placement of catheters is now possible using transrectal ultrasound to provide high quality implants. A number of centres have now developed this technique as a routine clinical tool. There remains variation in the optimal dose fractionation with a range of BED 10 values from 100 to 77 and BED 3 values from 246.6 to 122.5. This does not, however, take into account geometric variations in dose distribution exploiting the physical advantage of BT in achieving a rapid dose fall off close to critical structures such as the rectum. Early results show PSA response levels of around 90% with grade III toxicity in 5–9% of patients. Critical evaluation of this technique in prospective, randomized trials is required.

Accuracy of fluoroscopic localization of the Crista terminalis documented by intracardiac echocardiography.

The crista terminalis is an important anatomic target for ablation of atrial arrhythmias. We determined the accuracy of catheter placement guided by fluoroscopy alone when directed to 24 sites along the crista terminalis in 6 patients. The sites selected included the most medial superior, most lateral superior, mid lateral, and most inferolateral sites along the crista terminalis in each patient. These sites were selected because of their recognized importance in sinus node and/or atrial tachycardia ablation and the importance of avoiding caval structures when targeting the most superior and/or inferior right atrium. The position of the catheter tip was documented using a catheter based ultrasound transducer in the right atrium or vena cava. The operator was blinded to the intracardiac echocardiographic (ICE) results until reviewing the images after the procedure in each patient. The catheter tip, guided by fluoroscopy alone, was identified by ICE to be within the right atrium and within 1cm of the crista terminalis at only 10 of the 24 sites (42%). Importantly, when targeting the most superior and inferior sites along the crista terminalis, the catheter tip, guided by fluoroscopy, was noted to be adjacent to the venous junction with the right atrium but actually located in the superior or inferior vena cava at 5 of the 18 such sites. The catheter was positioned appropriately (within 1 cm of the crista and within the right atrium) guided by fluoroscopy alone when targeting 1 of the 12 sites in the first 3 patients versus 9 of 12 sites in the last 3 patients, p<0.05. In conclusion, it appears that using fluoroscopic guidance alone: 1) localization of the crista terminalis is frequently inaccurate and 2) catheter positioning in the superior/inferior vena cava is commonly noted when targeting very superior and inferior sites along the crista terminalis. A learning curve, assisted by review of ICE recordings after each procedure, appears to improve the accuracy of catheter placement by fluoroscopy alone but still does not result in uniform success. ICE appears to facilitate and ensure accurate targeting of specific anatomic sites along the crista terminalis and thus may serve as an important adjunctive imaging technique in electrophysiology.

Abdominal and Pelvic Therapeutic Procedures Using CT-Fluoroscopic Guidance

CT fluoroscopy (CTF) technology has been used for guidance of percutaneous interventional procedures at our institution since 1996. Since that time, we have performed over 120 therapeutic procedures of the abdomen and pelvis using the Toshiba Xpress/SX continuous imaging CTF system. Procedures discussed in this review include fluid collection aspiration and drainage, chemoneurolysis, and tumor chemoablation. CTF facilitates accurate and rapid placement of needles, guidewires, and drainage catheters. In addition, the ability to constantly monitor instrument placement allows percutaneous procedures to be performed in a very safe manner. Limitations on image quality using a low millamperage technique are less important when performing fluid collection drainages than when accessing tumor lesions within solid organs such as the liver for chemoablation.

Stereolithographic modelling as an aid to orbital brachytherapy

Purpose: This paper describes the technique of stereolithographic biomodelling and its application to a patient who was treated using orbital brachytherapy.Methods and Materials: The process uses a moving laser beam, directed by a computer, to draw cross-sections of the model onto the surface of photo-curable liquid plastic. Using a stereolithographic apparatus (SLA), solid or surface data is sliced by software into very thin cross-sections. A helium cadmium (HeCd) laser then generates a small intense spot of ultraviolet (UV) light that is moved across the top of a vat of liquid photo monomer by a computerised optical scanning system. The laser polymerises the liquid into a solid where it touches, precisely printing each cross-section. A vertical elevator lowers the newly formed layer, and a recoating and levelling system establishes the next layer’s thickness. Successive cross-sections (0.25 mm thick), each one adhering to the one below, are built one on top of the other, to form the part from the bottom up. The biomodel allowed the implant to be planned in detail prior to the surgery. The accurate placement of brachytherapy catheters was assured, and the dosimetry could be determined and optimised prior to the definitive procedure.Conclusions: Stereolithography is a useful technique in the area of orbital brachytherapy. It allows the implant to to be carried out with greater accuracy and confidence. For the patient, it minimises the risk to the eye and provides them with a greater understanding of the procedure.

Accurate placement of central venous catheters in pediatric patients using endocavitary electrocardiography: Reassessment of a personal technique

To avoid the need for radiological control in the assessment of the proper location of central venous catheters (CVC), a particular use of endocavitary electrocardiography (EC-ECG) was proposed 10 years ago. The aim of this study is to reassess our experience with this method. EC-ECG assumes that the CVC, when filled with normosaline and connected to a standard electrocardiograph, behaves like an exploring electrode. The approach of the catheter tip to the right atrium is then detected by a slightly increasing negative P wave. When the tip reaches the exact level of the sinus node, the P wave suddenly deepens. After a preliminary test of the reliability of the technique versus the standard method in 50 CVC placements verified by both EC-ECG and chest x-ray, we have placed 807 CVCs in children using EC-ECG only. There have been no false-positive and one false-negative test result (lead connector misplacement). In 17 cases in which intrinsic deflection was not detected, the catheter tip was found to be wrongly positioned; all the remainder CVCs have been successfully positioned. For 10 years this technique has proved to be a simple, safe, quick, inexpensive and highly reliable method to assess the correct positioning of the CVC.

Ultrasonic imaging as an adjunct to femoral venous catheterization in children.

Central venous catheterization is critically important to the management of burned children, but major morbidity is associated with the technical misadventures that can occur when inserting these devices. We used a bedside ultrasound device to facilitate placement of femoral venous catheters in eight edematous children with an average age of 7.0 years, weight of 23 kg, and burn size of 54%. To our knowledge, this is the first report of this technique in children. All children had central venous catheters placed in the femoral position requiring an average of 2 (range, 1 to 4) venepuncture attempts. There were no mechanical complications. We found the needle guide too cumbersome for our small patients, but found that the ability to mark the anatomy with a pen facilitated accurate catheter placement. In most patients, standard external anatomic landmarks are adequate for accurate catheter placement, however, in this initial experience, we found bedside ultrasound imaging to be a useful adjunct in selected patients with massive soft tissue edema.

Neuroanatomical and cranial geometry of the frontal horn of the lateral ventricle

In common practice ventricular catheterisation is dependent on accurate targeting of the lateral ventricles from external cranial landmarks. A ventricular catheter guide has been developed for rapid and accurate placement of ventricular catheters using a percutaneous technique and a narrow twist drill. Correct intraventricular placement is dependent on the width of the lateral ventricle and its distance from the midline, as well as depth from the cranial surface. In the present report data is presented obtained from coronal MRI studies describing the relationship between ventricular anatomy and cranial geometry. Within the frontal quadrant the centre of the frontal horn projection to the cranial surface where right angle intersection with the ventricle occurs is 3.28 cm (standard deviation, s.d. = 0.26) from the midline, at which point the mean depth from skin surface to the frontal horn is 5.97 cm (s.d. = 0.21). Optimal criteria for frontal ventriculostomy therefore comprises ventricular catheter passage at right angles to the scalp, approximately 3 cm from the midline to a depth of 6 cm from the skin where ventricular CSF should be encountered.

Intravascular MR tracking catheter: preliminary experimental evaluation.

This article reports on the preliminary evaluation of a new technique for guiding intravascular interventional procedures with MR imaging. Active real-time position monitoring of catheters with MR imaging is made possible by incorporating a small RF coil into the tip of the catheter. The purpose of this study was to evaluate the practicability and localizing precision of this MR catheter tracking technique in vitro and in vivo in comparison with fluoroscopy. Feed cables employing a 0.9-mm-diameter coaxial cable, a 0.5-mm-diameter partially shielded coaxial cable, and a twisted pair cable attaching RF coils at the catheter tip to a coaxial plug at the catheter base were assessed. Further, miniature copper loop RF coils of two, three, and four turns were tested. In vitro validation of MR tracking was achieved by using a phantom consisting of a water-filled harvested segment of human aorta and iliac arteries embedded in gel. Accuracy of catheter placement was compared with MR and fluoroscopy. Subsequently, the MR tracking technique was evaluated in a swine model using a prototype 5-French MR tracking catheter. A fully shielded coaxial cable was found to be crucial for localizing the attached RF coil by means of the tracking technique. The number of coil turns had a lesser impact. Positions of the catheter tip measured with the MR technique and with fluoroscopy correlated well (r > .98), with a 6-mm 95% confidence interval of positional differences. Active real-time tracking of the coil-tipped catheters was achieved both in vitro and in vivo. The 5-French tracking catheter was successfully placed in the splenic and renal arteries of the swine. Robust in vivo tracking and accurate placement of catheters equipped with miniature RF coils are possible with MR imaging.

A guide to placement of parietooccipital ventricular catheters. Technical note.

Accurate placement of parietooccipital ventricular catheters can be difficult and frustrating. To minimize the morbidity of the procedure and lengthen the duration of shunt function, the catheter tip should lie in the ipsilateral frontal horn. The authors describe a posterior ventricular guide (PVG) for placement of parietooccipital catheters that operates by mechanically coupling the posterior burr hole to the anterior target point. In a series of 38 patients who underwent ventriculoperitoneal shunting with the assistance of the guide, postoperative computerized tomography (CT) scanning revealed that 35 (92.0%) had accurate catheter placement. In comparison, a retrospective review of free-hand posterior catheter placement revealed good catheter position in only 22 of 43 patients (51.1%). The use of the guide added less than 5 minutes to the entire procedure, and there were no complications related to its use. The PVG is a simple and useful tool that aids in the placement of parietooccipital ventricular catheters.

Peripheral Transluminal Angioplasty under Ultrasound Guidance: Initial Clinical Experience and Prevalence of Lower Limb Lesions Amenable to Ultrasound-Guided Angioplasty

Purpose: Currently, endovascular techniques require monitoring by radiographic imaging for accurate catheter placement. The aim of this study was first to determine the feasibility of angioplasty under ultrasound guidance using a special catheter system. Based on this outcome, the second goal was to investigate the prevalence of lesions amenable to ultrasound-guided angioplasty. Methods: A balloon catheter system (Echomark) has been developed, which allows accurate catheter guidance by ultrasound imaging. An ultrasound-sensitive piezoelectric sensor positioned in the middle of the balloon portion of the angioplasty catheter is interfaced to an external duplex scanner via the catheter system. The exact position of the balloon relative to the transducer is calculated and reproduced on the screen of the duplex scanner to guide balloon positioning. In the feasibility assessment of the procedure, 16 patients with disabling claudication and rest pain were selected for balloon angioplasty under ultrasound guidance based on arteriographic and hemodynamic lesion criteria of &gt; 50% stenosis with a peak systolic velocity ratio &gt; 2.5 in a lesion &lt; 4 cm long that could be imaged by duplex ultrasonography. A fall in the peak systolic velocity ratio below 2.0 was selected for a procedural endpoint corresponding to &lt; 30% residual stenosis on the completion angiogram. In the second part of the study, the prevalence of stenoses amenable to ultrasound-guided angioplasty was studied in 80 patients presenting with symptoms of peripheral arterial disease. Results: In the feasibility study, 20 stenoses (5 common iliac, 6 external iliac, and 8 superficial femoral arteries and 1 graft) meeting the inclusion criteria were subjected to ultrasound-guided angioplasty with confirmation by completion angiography. The procedure was possible in 18 (90%) of the 20 stenoses. The two failures occurred in iliac arteries that could not be imaged by duplex scanning due to obesity, bowel gas, and/or vessel wall calcification. In one case, the peak systolic velocity ratio exceeded 2.5 despite a satisfactory control arteriogram; redilation was performed, and the ratio fell below 2.0. In the second part of the study, 21 (26.2%) of the 80 patients had 29 stenoses that were amenable to angioplasty according to angiographic criteria (&gt; 50% stenosis and &lt; 4 cm length). All these stenoses were evaluated with duplex scanning to determine their suitability for angioplasty under ultrasound guidance. Twenty-three (79%) of the 29 lesions selected for angioplasty were well visualized by duplex, and angioplasty would have been possible based on our initial clinical experience. Conclusions: Angioplasty under ultrasound control is a feasible technique for peripheral lesions. Ultrasound allows monitoring of both anatomical and hemodynamic parameters during angioplasty and thus provides a procedural endpoint that correlates to the control angiogram. A large proportion (79%) of stenoses deemed suitable for angioplasty can be well visualized by ultrasound, but obesity, vessel wall calcification, and bowel gas may limit the ability to obtain a satisfactory ultrasound image. Ultrasound-guided angioplasty is a potentially useful procedure that warrants further investigation.

Peripheral transluminal angioplasty under ultrasound guidance: initial clinical experience and prevalence of lower limb lesions amenable to ultrasound-guided angioplasty.

Currently, endovascular techniques require monitoring by radiographic imaging for accurate catheter placement. The aim of this study was first to determine the feasibility of angioplasty under ultrasound guidance using a special catheter system. Based on this outcome, the second goal was to investigate the prevalence of lesions amenable to ultrasound-guided angioplasty. A balloon catheter system (Echomark) has been developed, which allows accurate catheter guidance by ultrasound imaging. An ultrasound-sensitive piezoelectric sensor positioned in the middle of the balloon portion of the angioplasty catheter is interfaced to an external duplex scanner via the catheter system. The exact position of the balloon relative to the transducer is calculated and reproduced on the screen of the duplex scanner to guide balloon positioning. In the feasibility assessment of the procedure, 16 patients with disabling claudication and rest pain were selected for balloon angioplasty under ultrasound guidance based on arteriographic and hemodynamic lesion criteria of > 50% stenosis with a peak systolic velocity ration > 2.5 in a lesion < 4 cm long that could be imaged by duplex ultrasonography. A fall in the peak systolic velocity ratio below 2.0 was selected for a procedural endpoint corresponding to < 30% residual stenosis on the completion angiogram. In the second part of the study, the prevalence of stenoses amenable to ultrasound-guided angioplasty was studied in 80 patients presenting with symptoms of peripheral arterial disease. In the feasibility study, 20 stenoses (5 common iliac, 6 external iliac, and 8 superficial femoral arteries and 1 graft) meeting the inclusion criteria were subjected to ultrasound-guided angioplasty with confirmation by completion angiography. The procedure was possible in 18 (90%) of the 20 stenoses. The two failures occurred in iliac arteries that could not be imaged by duplex scanning due to obesity, bowel gas, and/or vessel wall calcification. In one case, the peak systolic velocity ratio exceeded 2.5 despite a satisfactory control arteriogram; redilation was performed, and the ratio fell below 2.0. In the second part of the study, 21 (26.2%) of the 80 patients had 29 stenoses that were amenable to angioplasty according to angiographic criteria (> 50% stenosis and < 4 cm length). All these stenoses were evaluated with duplex scanning to determine their suitability for angioplasty under ultrasound guidance. Twenty-three (79%) of the 29 lesions selected for angioplasty were well visualized by duplex, and angioplasty would have been possible based on our initial clinical experience. Angioplasty under ultrasound control is a feasible technique for peripheral lesions. Ultrasound allows monitoring of both anatomical and hemodynamic parameters during angioplasty and thus provides a procedural endpoint that correlates to the control angiogram. A large proportion (79%) of stenoses deemed suitable for angioplasty can be well visualized by ultrasound, but obesity, vessel wall calcification, and bowel gas may limit the ability to obtain a satisfactory ultrasound image. Ultrasound-guided angioplasty is a potentially useful procedure that warrants further investigation.

Resolution of pace mapping stimulus site separation using body surface potentials.

Several studies have related 12-lead ECG waveform during ventricular tachycardia to ECG waveform during ventricular pacing to identify ablation sites for therapy of ventricular tachycardia. QRS isopotential maps and QRS isointegral maps derived from body surface isopotential maps have also been correlated with left ventricular pacing sites with the same objective. The comparison process used is subjective and only semiquantitative. Improved accuracy of catheter placement may improve success rates of ablation therapy. This animal study was performed to determine the spatial resolution with which left ventricular pacing sites could be distinguished by body surface isopotential mapping. Potentials were recorded from 64 evenly spaced thoracic leads. Hexapolar or octapolar pacing catheters with 2-mm interelectrode spacing were placed percutaneously in the left ventricle in each of six dogs, and bipolar endocardial pacing was performed using each pair of adjacent electrodes. QRS isopotential maps of each pacing site for each catheter placement were cross-correlated by computer. Difference maps for each pair of pacing sites were calculated lead by lead and time instant by time instant, and root-mean-square voltage differences were calculated. Results indicated that correlation coefficients and root-mean-square error of voltage differences monotonically decrease and increase, respectively, with stimulus site separation. Both measures were significantly different (P < .05) for separations of 4 mm or more. A method of quantitative comparison of body surface potential maps can be used in normal hearts to localize ventricular pacing sites within a 4-mm range. The method may have utility in determining potential ablation sites for therapy of ventricular tachycardia or preexcitation syndromes.

Accurate Placement of Central Venous Catheters

MCGEE, WILLIAM T.; ACKERMAN, BARBARA L.; ROUBEN, LAWRENCE R.; PRASAD, VEMULAPALI M.; BANDI, VENKATTA; MALLORY, DOUGLAS L. Author Information