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PubMed2006

Flat-panel detectors: how much better are they?

Interventional and fluoroscopic imaging procedures for pediatric patients are becoming more prevalent because of the less-invasive nature of these procedures compared to alternatives such as surgery. Flat-panel X-ray detectors (FPD) for fluoroscopy are a new technology alternative to the image intensifier/TV (II/TV) digital system that has been in use for more than two decades. Two major FPD technologies have been implemented, based on indirect conversion of X-rays to light (using an X-ray scintillator) and then to proportional charge (using a photodiode), or direct conversion of X-rays into charge (using a semiconductor material) for signal acquisition and digitization. These detectors have proved very successful for high-exposure interventional procedures but lack the image quality of the II/TV system at the lowest exposure levels common in fluoroscopy. The benefits for FPD image quality include lack of geometric distortion, little or no veiling glare, a uniform response across the field-of-view, and improved ergonomics with better patient access. Better detective quantum efficiency indicates the possibility of reducing the patient dose in accordance with ALARA principles. However, first-generation FPD devices have been implemented with less than adequate acquisition flexibility (e.g., lack of tableside controls/information, inability to easily change protocols) and the presence of residual signals from previous exposures, and additional cost of equipment and long-term maintenance have been serious impediments to purchase and implementation. Technological advances of second generation and future hybrid FPD systems should solve many current issues. The answer to the question "how much better are they?" is "significantly better", and they are certainly worth consideration for replacement or new implementation of an imaging suite for pediatric fluoroscopy.

Body Burden↗
PubMed1999

Intestinal intussusception survey about diagnostic and nonsurgical therapeutic procedures.

OBJECTIVE: To provide an overview of the diagnostic and therapeutic procedures performed by European paediatric radiologists in the management of intussusception. MATERIALS AND METHODS: A postal survey was sent to the European members of ESPR. Items surveyed included diagnostic imaging procedures (plain films, US, contrast enema [CE]), contrast medium used (barium, iodine, air, saline solution), and imaging technique used for monitoring during reduction (films, fluoroscopy, US). Multiple answers were possible. Other data, including contraindications, maximum pressure, pressure and irradiation monitoring, presence of a surgeon, sedation, number and duration of attempts, and hospitalisation were also obtained and analysed. RESULTS: There were 204 respondents (60.2 %). Regarding diagnosis, 72.5 % of respondents used plain radiographs, 93 % US, and 34 % CE. Reduction was performed using air (55 %), a barium suspension (32 %), iodinated contrast medium (24 %), or a saline solution (10 %). Reduction was monitored using fluoroscopy alone (46 %), fluoroscopy and radiographs (49.5 %), US alone (9.5 %), or a combination of radiology and US (18 %). Pressure was monitored by 81 % of respondents. Most respondents (82.4 %) used a maximum pressure between 100 and 120 mm Hg. CONCLUSIONS: US is widely used for diagnosing intussusception. For treatment, contrast medium and air reduction are used almost equally. A large number of radiologists are now performing intussusception reduction using US monitoring.

Child↗
PubMed2003

Navigation-assisted, minimally invasive implant removal following a triple pelvic osteotomy.

INTRODUCTION: Triple pelvic osteotomy is known as a surgical option in young patients suffering from severe hip dysplasia. In most patients, implant removal is performed after bony consolidation. Due to the pelvic anatomy, the conventional technique is often associated with soft-tissue damage and high X-ray exposure. Recent developments in the field of computer-assisted surgery may offer new alternatives. The aim of this case report was to investigate the feasibility of a fluoroscopy-supported navigation system for the implant removal after a triple pelvic osteotomy. MATERIALS AND METHODS: Using the BrainLAB-VectorVision, a fluoroscopy-enhanced navigation system, implants were removed in a 24-year-old female patient 14 months after a triple pelvic osteotomy. RESULTS: The navigation system showed a high feasibility in the instrument visualisation and implant localisation. The screws could be precisely located, simultaneously in different X-ray planes. The total X-ray exposure time was low, totalling 17 s. CONCLUSION: Initial experiences are very promising and show impressively the advantages of fluoroscopy-supported navigation for minimally invasive implant removal. A considerably reduced X-ray exposure for patient and surgeon is possible. The removal of the inserted screw is possible through a stitch incision, with reduced OR trauma and a quicker reconvalescence.

Adult↗
PubMed2006

Optimal target temperature for slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia.

OBJECTIVE: To define optimal target temperature for the slow pathway ablation. MATERIALS AND METHODS: In this study, 268 patients with atrioventricular nodal reentrant tachycardia (190 females; mean age, 49 +/- 14 years) who underwent slow pathway ablation using a combined electroanatomic approach were enrolled. The patients were categorized into Group 1 if target temperature was < 55 degrees C or into Group 2 if target temperature was > or = 55 degrees C. Group 2 was divided into three subgroups of 55 degrees C (Sgp-1), 60 degrees C (Sgp-2), and 65 degrees C (Sgp-3). RESULTS: Acute success rate was similar in both groups (P = 0.83). The ablation time (26.2 +/- 20 vs. 36.5 +/- 28 min; P = 0.014), fluoroscopy time (11.6 +/- 9.7 vs. 17.8 +/- 16.6 min; P = 0.035), and number of applications (4.1 +/- 3.2 vs. 9.1 +/- 6.5; P = 0.02) were lower for Group 2 than Group 1 patients. The frequency of AV or VA block, impedance rise, and coagulum formation were comparable in two groups (all P > 0.05). During mean follow-up of 14 +/- 3 months, recurrence of the arrhythmia was seen in higher proportion of Group 1 than Group 2 patients (P = 0.036). Among the Group 2 patients, there were no significant differences between the three subgroups in terms of acute success rate, fluoroscopy time, risks of AV and VA block, pericardial effusion, and recurrence (All P > 0.05). Number of applications and RF pulse duration were lower in Sgp-2 and 3 compared to Sgp-1 (All P > 0.05). Impedance rise and coagulum formation were slightly higher in Sgp-3 compared to Sgp-1 and 2 but this difference did not reach statistical significance (All P > 0.05). CONCLUSIONS: Compared to less than 55 degrees C, target temperatures > or = 55 degrees C during slow pathway ablation significantly reduces fluoroscopy time, RF pulse duration, number of RF applications, and recurrence of AVNRT without increase in risk of AV or VA block or coagulum formation.

Catheter Ablation↗
PubMed2005

Mitral valvuloplasty by inoue balloon under transthoracic echocardiographic guidance.

BACKGROUND: Mitral valvuloplasty traditionally performed under fluoroscopic guidance has emerged as an effective nonsurgical technique for the treatment of symptomatic patients with mitral stenosis. We undertook a study to evaluate the feasibility of performing valvuloplasty by the Inoue balloon solely under transthoracic echocardiographic (TTE) guidance with the backup of transesophaeal echocardiography (TEE) and fluoroscopy. METHODS: Between September 2003 and July 2004, mitral valvuloplasty using the Inoue balloon was performed solely under TTE guidance in the catheterization laboratory with backup of fluoroscopy and TEE in 75 patients (52 female patients, including 18 who were pregnant, and 23 male patients) with symptomatic mitral stenosis (New York Heart Association class II-IV) with satisfactory TTE window and valve morphology suitable for valvuloplasty. RESULTS: The procedure was technically successful (no requirement of TEE or fluoroscopy) in 68 patients (89%). TEE was required for septal puncture in 3 patients whereas fluoroscopic assistance was required to complete the procedure in 4 patients. Procedural success after valvuloplasty (doubling of mitral valve area or mean gradient across mitral valve < 5 mm Hg in absence of complications like severe mitral regurgitation or tamponade) was achieved in 70 patients. There was an increase in mean mitral valve area as assessed echocardiographically from 0.84 +/- 0.16 cm2 to 1.7 +/- 0.27 cm2 with decrease in mean diastolic gradient from 27.2 +/- 8.4 mm Hg (18-36 mm Hg) to 5.2 +/- 4.1 mm Hg (3-14 mm Hg). The mean procedure time was 27.2 +/- 8.4 minutes (15-45 minutes). Mild mitral regurgitation appeared or increased in severity to moderate degree as assessed by color Doppler during the procedure in 11 patients (14.6%) but no patient developed severe mitral regurgitation. No patient had cardiac tamponade as puncture of the septum under TTE guidance prevents inadvertent puncture of the aorta, coronary sinus, inferior vena cava, and right atrial and left atrial wall that sometimes occurs during septal puncture under fluoroscopic guidance. CONCLUSION: Balloon mitral valvuloplasty under sole TTE guidance is safe and feasible in experienced hands.

Adolescent↗
PubMed2006

Use of intra-cardiac ultrasound in the diagnosis of prosthetic valve malfunction.

A 46-year old lady was under regular follow up for aortic valve replacement done in 2002 for aortic stenosis. The valve was a Carbomedics 19 mm bi-leaflet aortic valve prosthesis for which she had adequate anticoagulation since implantation. She had a past history of end stage renal failure, type 2 diabetes, hypertension, cerebrovascular disease and systemic lupus erythematosus. She was asymptomatic and had a routine transthoracic echocardiogram performed which revealed that her aortic valve prosthesis was well seated with an elevated velocity across the valve; the aortic valve leaflets were poorly visualised but appeared to be mobile. A transoesophageal echocardiogram (TOE) confirmed the markedly increased forward velocity across the aortic valve (maximum velocity 4.6 m/s) with small aortic root raising the possibility of pressure recovery phenomenon. Once again the leaflets were not clearly seen but appeared mobile despite the use of deep trans-gastric view. Fluoroscopy was performed and revealed that one of the leaflets was not moving. The patient had an intra-cardiac ultrasound scan (ACUSON AcuNav; Siemens) with the probe of the scanner within the right atrium. A long-axis view demonstrated the prosthetic aortic valve leaflets clearly (Fig. 1). A short-axis view of the prosthetic valve revealed an echogenic area at the six o'clock position; this may be due to pannus formation (Fig. 2); colour flow across the valve during systole revealed absence of colour flow though one of the leaflets due to the leaflet being stuck (Fig. 3). The sewing cuff of the Carbomedics valve is coated with biolite carbon, which is an anti-thrombotic agent that prevents adhesion of thrombus or pannus on the sewing cuff. There are few reports of Carbomedics valve dysfunction by pannus formation in the mitral position but none in the aortic position. Fluoroscopy can be used to visualize mobility of valve leaflets but is unable to identify thrombus/pannus formation that may be causing the valve to stick. Intra-cardiac echocardiography (ICE) can provide additional information regarding potential causes of valve dysfunction such as pannus/thrombus formation. However, ICE does suffer from the same limitations as TOE in obtaining sufficiently adequate images of the aortic valve to allow appropriate assessment of leaflet motion and insight into flow channels; it is also more invasive and expensive compared with other imaging modalities. In our patient ICE provided better images than TOE, possibly due to the closer proximity of the probe to the aortic root compared with TOE. ICE is a novel tool in the assessment of prosthetic valve function, which can complement data obtained from transthoracic/transoesophageal echocardiography and fluoroscopy.

Aortic Valve Stenosis↗
PubMed2005

The role of 3-D rotational x-ray imaging in spinal trauma.

The most widely used imaging devices in trauma spine surgery are fluoroscopy and computed tomography. Both techniques have their specific pros and cons and expose both patient and operating staff to considerable radiation during image acquisition. Three-dimensional-rotational x-ray imaging (3-DRX) is a relatively new technique in which a C-arm is moved around the patient to allow for an "acquisition run" during which multiple fluoroscopy images are obtained. The images can subsequently be processed on a workstation into a 3-D volume, which can then be manipulated in a similar way to 3-D computed tomography data. The 3-DRX technique combines the advantages of both fluoroscopy and computed tomography: fast visual feedback and high resolution multiplanar reformatted images, respectively, and could be used in an intraoperative setting. In this paper some technical aspects of 3-DRX imaging and its potential role in spinal trauma treatment are presented.

Humans↗
PubMed1998

An easier method for percutaneous endoscopic gastrojejunostomy tube placement.

BACKGROUND: The current procedures for percutaneous endoscopic gastrojejunostomy (PEG-J) tube placement require fluoroscopy and are time consuming. We describe a new, simple method. METHODS: Ten patients had a PEG-J tube placed by the new method. After placement of a percutaneous endoscopic gastrostomy (PEG) tube using standard technique, the PEG tube was pushed up to the pylorus to make it easier to place the jejunal tube into the duodenum without looping in the stomach. Fluoroscopy was not used. The position of the tube was confirmed by a plain x-ray film of the abdomen. RESULTS: The mean time required for PEG placement and jejunal tube placement was 9.0 and 8.2 minutes, respectively. In all patients the tip of the jejunal tube was at the ligament of Treitz. In one patient the jejunal tube formed a loop in the duodenum, but this was reduced by spontaneous forward migration. In another patient, the tube migrated back into the stomach after 1 week. CONCLUSION: The method described allows easier PEG-J placement without fluoroscopy.

Endoscopy↗
PubMed2000

Airway foreign bodies (FB): a 10-year review.

A retrospective chart review of children who had airway foreign body removed via direct laryngoscopy and bronchoscopy (DLB) from 1987-1997 was conducted in Children's Hospital, Boston. Patient characteristics noted included age, sex, and clinical presentation. Pre-operative radiographic findings, reason for delay in evaluation, DLB findings, length of procedure, reason for repeat DLB, and types of foreign body etc. were recorded. Serious complications from aspirated foreign bodies such as severe airway obstruction and death tend to occur in infants and younger children because of their small airway size. A history compatible with foreign body aspiration dictates diagnostic endoscopy with or without radiologic confirmation. Chest and airway radiographs supplemented by fluoroscopy can increase the ratio of correct and early diagnosis. Fluoroscopy should be universally accepted as an initial diagnostic technique in airway foreign body evaluation. Fluoroscopy is not a worthwhile investigation if a preceeding chest radiograph suggests the presence of a foreign body. Long-standing airway foreign bodies are associated with considerable morbidity, and early diagnosis remains the key to successful and uncomplicated management of foreign body aspiration. Education aimed at increasing diagnostic acumen of the physicians and heightening of public awareness are the most important steps needed to reduce the morbidity and mortality. Parents should be instructed to abstain from feeding nuts and seeds to young children and to keep small, potentially ingestible objects out of their reach.

Age Distribution↗
PubMed2000

The advantages of On-line transesophageal echocardiography guide during percutaneous balloon mitral valvuloplasty.

The purpose of this study was to evaluate the potential advantages of on-line transesophageal echocardiography during percutaneous balloon mitral valvuloplasty (PBMV). One hundred thirty-four consecutive patients who underwent PBMV were included in this study. Group 1 included 64 patients who underwent PBMV under fluoroscopy guide only, and group 2 included 70 patients who underwent PBMV under on-line transesophageal echocardiography guide. Inoue balloons were used in all cases. The mitral valve area after valvuloplasty was comparable between the 2 groups. The procedure time was significantly shorter in group 2 (99 +/- 48 min vs 64 +/- 22 min, P <.0001 ), and the average fluoroscopy time was shorter in group 2 without statistical significance (30 +/- 17 min vs 19 +/- 15 min, P =.25 ). Five (7.8%) patients in group 1 and 2 (2.8%) patients in group 2 underwent surgery because of procedure-related complications. The limitation of this study was the learning curve of the operator, because the 2 groups were treated serially. In conclusion, transesophageal echocardiography can be used effectively during balloon mitral valvuloplasty, and it may help to reduce the rate of complications resulting from trans-septal catheterization and balloon valvuloplasty and to reduce procedure time and fluoroscopy time.

Adult↗
PubMedDate not supplied

Analysis of radiation scatter during angiographic procedures: evaluation of a phantom model and a modified radiation protection system.

PURPOSE: To study the radiation scattering associated with the digital subtraction angiography (DSA) unit in angiographic procedures and to design an effective radiation protection shield based on these data. MATERIALS AND METHODS: The number of scattered photons was measured at three points relative to the operator's position. Anteroposterior abdominal and lateral cranial fluoroscopy were evaluated. As protective devices, a lead curtain, sliding shields, and a brim-shaped image intensifier (II) hood were designed. RESULTS: In abdominal fluoroscopy, radiation was found to scatter to the operator's lower limbs from the underside of the catheter table, to the abdomen from the side of the patient's body, and to the head and neck from the table surface adjacent to the patient. The use of protective devices reduced exposure from 2.89 to 0.058 mR/min for the operator's lower limbs, from 0.987 to 0.069 mR/min for the operator's abdomen, and from 0.696 to 0.139 mR/ min for the operator's head and neck area. With lateral cranial fluoroscopy, radiation was detected to scatter to the operator's lower limbs from the underside of the catheter table, to the abdomen from the patient's temporal area, and to the head and neck from the patient's face. The use of protective devices reduced exposure from 0.248 to 0.010 mR/min for the operator's lower limbs, from 0.129 to 0.010 mR/min for the operator's abdomen, and from 0.162 to 0.018 mR/min for the operator's head and neck area. CONCLUSIONS: The characteristic directions of scattering to the operator were identified. An effective modified radiation protection system was designed based on this information.

Abdomen↗
PubMed2000

Regional differences in intestinal spreading and pH recovery and the impact on salmon calcitonin absorption in dogs.

PURPOSE: To investigate the regional influence of intestinal spreading and pH recovery on the performance of drug and excipient delivery systems and their impact on the oral absorption of a model peptide drug, salmon calcitonin (sCT), in conscious beagle dogs. METHODS: Male beagle dogs were surgically prepared with subdermal Intestinal Access Ports (IAP). The catheter from one port was placed in the duodenum and the other in the ileum. Fluoroscopy and Heidelberg pH capsule studies were performed to characterize intestinal spreading and pH recovery, respectively. Three treatments were performed: (1) a radiopaque dye and citric acid (CA) were infused into the intestinal segments, (2) a radiopaque powder capsule containing CA was given orally, and (3) capsules containing CA and sCT were given orally. Regular blood samples were collected and analyzed by radioimmunoassay (RIA) to determine the absorption characteristics of sCT. RESULTS: Since sCT is an excellent substrate for the pancreatic serine protease trypsin, the rate of degradation of sCT in the GI lumen is dependent upon the regional pH, activity of digestive enzymes and the concentration of sCT at the site of absorption. Fluoroscopy results clearly showed that when the radiopaque dye was infused into the duodenum and capsule disintegration occurred early, there was significant dilution and spreading of the excipients throughout a large section of the upper small intestine (USI). However, when the radiopaque dye was infused into the ileum and capsule disintegration occurred in the lower small intestine (LSI), the excipients moved along as a bolus (i.e., plug). The pH monitoring results were consistent with the fluoroscopy results. The pH dropped only momentarily and rose quickly in the USI consistent with well-stirred mixing kinetics. In the LSI, dilution and spreading were minimal and the drop in pH was greater and persisted for a longer period of time. Plasma levels of sCT were maximal when disintegration occurred in the LSI. CONCLUSIONS: Since significantly less dilution and spreading occurred in the LSI, the exposure of the intestine to pharmaceutical excipients and sCT was more concentrated resulting in a higher fraction of sCT absorbed. The results of this study demonstrate that intestinal mixing kinetics have a dramatic impact on the ability of pharmaceutical excipients to modulate the oral bioavailability of peptide drugs like sCT.

Administration, Oral↗
PubMed2002

Primary radiofrequency ablation for incessant idiopathic ventricular tachycardia.

Fascicular VT and RVOT tachycardia are sometimes difficult to induce by programmed electrical stimulation (PES), despite pharmacologic provocation. In such instances, catheter mapping is hampered and efficacy of catheter ablation is difficult to judge. The study included nine patients who presented with incessant idiopathic VT and were directly taken to the electrophysiological laboratory for RF ablation. During the same period, elective ablation was performed on 108 patients with idiopathic VT. The success rate, procedural and fluoroscopy times number of energies, and the peak temperature were evaluated and compared. Of the nine patients, seven had incessant fascicular VT and two had RVOT tachycardia. The mean VT cycle length was 356 +/- 32 ms and the earliest endocardial activation time during VT was 23.6 +/- 6 ms relative to surface QRS complexes. A fascicular potential was not seen in three of the seven patients with fascicular VT. The mean procedural time was 71 +/- 32 minutes and 144 +/- 40 minutes (P = 0.023) while the fluoroscopy time was 14.6 +/- 4.6 minutes and 30 +/- 16 minutes (P < 0.001), respectively, in the primary ablation and elective groups. The total number of RF energies delivered was 2.0 +/- 1.3 versus 7.4 +/- 5.6 (P = 0.07), respectively. The significantly increased procedural time during elective ablation was largely due to time spent in fascicular VT induction. All patients in the primary ablation group were successfully ablated and none had a recurrence. Primary ablation is a safe and effective option in patients with incessant idiopathic VT. Moreover, in fascicular VT, it is superior to elective ablation in terms of success, fluoroscopy and procedural times.

Adolescent↗
PubMed2000

[Reduction of the radiation exposure of patients caused by selected interventional and angiographic procedures].

PURPOSE: To reduce patient doses caused by selected interventional and angiographic procedures using the digital C-arm unit "Multiskop". MATERIALS AND METHODS: After a patient study done previously, physical measurements with test phantoms were carried out, and physical-technical parameters such as distance between focus and image intensifier, additional filtration, and radiation dose per image were optimised. Then, the dose-area product (DAP) and the fluoroscopic time were measured for 130 percutaneous transluminal angioplasties (PTA), 40 PTA with stent implantation, 61 embolisations, and 302 digital subtraction angiographies (DSA). In the case of 16 PTA, 9 embolisations, and 38 DSA the number of radiographs was determined, and the DAP was divided into two parts, fluoroscopy and radiography. The measuring values were compared with data of the patient study done previously. RESULTS: The median values of the DAP and the fluoroscopic time amounted to 25 Gy cm2 and 9.7 min for PTA, 97 Gy cm2 and 8.5 min for PTA with stent implantation, 88 Gy cm2 and 17.2 min for embolisation as well as 54 Gy cm2 and 2.8 min for DSA. For the relation between DAP caused by fluoroscopy and radiography, and the number of radiographs, median values of 0.76 and 63 for PTA, 0.81 and 123 for embolisation as well as 1.85 and 134 for DSA were determined. In comparison to the patient study done previously the median values of the DAP were reduced by 31% for PTA, 26% for PTA with stent implantation, 55% for embolisation, and 38% for DSA. CONCLUSIONS: The comparison between the patient studies done previously and recently indicates the great potential of dose reduction for interventional and angiographic procedures. Although the X-ray equipment is ten years old the patient dose can be reduced by organizational and physical-technical modifications to such an extent that preliminary national reference dose values will not be exceeded. For further significant dose reductions while maintaining adequate image quality it will be necessary to purchase a modern X-ray equipment with pulsed fluoroscopy and automatic filter selection.

Angiography↗
PubMed2001

Resource utilization and clinical outcomes of coronary stenting: a comparison of intravascular ultrasound and angiographical guided stent implantation.

BACKGROUND: Intravascular ultrasound (IVUS) guided stent implantation studies have demonstrated that inadequate stent implantation can occur despite achieving an optimal angiographic result. Furthermore, IVUS-guided stent implantation has been shown to improve lesional acute gain. However, it is unknown whether the use of IVUS guidance during stent implantation is associated with improved acute and long-term clinical outcomes. Moreover, the additional procedural cost and time incurred with the use of IVUS-directed stent implantation has not been evaluated. Thus the purpose of this study was to determine whether IVUS-guided stent implantation is associated with improved clinical outcomes compared with angiographically guided stent implantation and to evaluate the difference in resource utilization between these respective stent deployment strategies. METHODS: Data were collected on 278 consecutive patients in whom 455 stents were deployed in native coronary arteries. High-pressure (> or = 12 atm) balloon inflations were performed until an optimal angiographic result was obtained. In the angiographically guided group, no IVUS imaging was performed. In the IVUS-guided group, IVUS imaging and additional interventions were performed attempting to achieve full apposition, absence of edge tear, and acute gain (lesion lumen area: distal reference lumen area) > or = 0.8 in subsequent IVUS imaging. Total procedure time, fluoroscopy time, contrast media volume, number of balloons, stents, guidewires, guide catheters, and procedural cost were calculated. In hospital abrupt closure rate and 6-month major adverse cardiovascular events (cardiac death, myocardial infarction, target vessel revascularization) rate were obtained. RESULTS: A total of 178 patients underwent IVUS-guided stent placement and 100 patients underwent angiographically guided stent implantation. There was no significant difference in procedure time (107 +/- 49 vs 100 +/- 50 minutes, P = .22), fluoroscopy time (33 +/- 24 vs 30 +/- 18 minutes, P = .36), contrast volume (411 +/- 157 vs 386 +/- 181 mL, P = .23), guide catheters (1.3 +/- 0.8 vs 1.3 +/- 0.6, P = .69), guidewires (1.6 +/- 1.2 vs 1.6 +/- 1.0, P = .99), balloons (2.4 +/- 1.0 vs 2.3 +/- 1.3, P = .58), and stents (1.7 +/- 0.9 vs 1.6 +/- 0.9, P = .42). Intraprocedural cost was significantly higher in the IVUS-guided group, $4142 +/- 1547 verus $3635 +/- 1949 (P = .03), which was primarily related to the cost of the IVUS catheter. However, the in-hospital acute vessel closure rate was significantly lower in the IVUS-guided group, 0.6% versus 4% (P = .04). There was a trend toward lower target vessel revascularization rate in the IVUS-guided group (11% vs 19%, P = .08). By multivariate analysis IVUS use was demonstrated to be an independent negative predictor of cardiac death, myocardial infarction, repeat revascularization, and abrupt stent closure with a relative risk of 0.49 (95% confidence interval of 0.25 to 0.98), and P = .04. CONCLUSIONS: The use of IVUS guidance during stent implantation does not significantly increase procedure time, fluoroscopy exposure, contrast volume, or device utilization. Furthermore, despite the increase in procedural cost, IVUS-guided stent implantation is associated with a significant decrease in the in-hospital abrupt closure rate and a trend toward a lower 6-month target vessel revascularization.

Aged↗
PubMed2002

Catheter-based interventions guided solely by a new phased-array intracardiac imaging catheter: in vivo experimental studies.

BACKGROUND: Intracardiac echocardiography (ICE) has had useful but limited use during interventional procedures because of technologic limitations. We used a novel phased-array ICE device (AcuNav) with 2-dimensional sector imaging and full Doppler capability to see whether it could guide cardiac interventions without fluoroscopy. METHODS: Twelve dogs were studied, and we performed atrial septostomy, tricuspid, and pulmonary valve disruption using only ICE. Preinterventional and postinterventional anatomic and hemodynamic data were noted. RESULTS: All attempts were successful in the placement of the ICE catheter (100%). We attempted septostomy on 11 dogs and were successful 8 times (73%). Tricuspid valve disruption and balloon dilatation were performed successfully on 5 dogs (100%). We attempted pulmonary valve disruption on 4 dogs and could always correctly place the guidewire (100%). We performed pulmonary valve balloon dilatation on one dog (25%). A comprehensive echocardiographic examination was always possible. CONCLUSION: This new ICE device can guide interventions without fluoroscopy. However, further studies are needed to evaluate whether it can replace fluoroscopy.

Animals↗
PubMed2003

X-ray based imaging for computer-assisted surgery.

X-ray based imaging is routinely used for preoperative diagnosis and planning, for intraoperative guidance and control, and for the postoperative evaluation of computer-assisted surgery (CAS) in the majority of its applications. Standard radiography, fluoroscopy and computed tomography (CT) are the modalities of outstanding importance. In this report we will review the state of the art in fluoroscopy and in CT with respect to technology and physics, but -- except for detector technology -- we will neglect standard radiography. Recent technical developments which aim at providing CT capabilities for standard fluoroscopy equipment are of particular topical importance; they can significantly improve workflow in the operating room (OR). Considerations regarding x-ray doses are of high concern. Our analysis indicates that most types of applications, including CT, do not bear considerable risks. However, fluoroscopic interventions with long exposure times have to be carefully monitored.

Journal Article↗
PubMed2001

Transseptal catheterization without needle puncture.

OBJECTIVE: The aim was to see if probing the fossa ovalis for transseptal puncture during balloon mitral valvuloplasty will reduce time consumed for the procedure. DESIGN: Twenty-five patients had probing of fossa ovalis for left atrial entry (group I). In 30 patients (group II), standard needle puncture was done for left atrial entry. Puncture time and fluoroscopy time were noted and oxymetry was done. Later, a further 60 patients underwent probing of fossa ovalis for validation of the technique. RESULTS: Puncture times in groups I and II were 84.7 +/- 27.5 and 116.1 +/- 37.9 s, respectively (p < 0.02). Fluoroscopy time was 51.2 +/- 19.6 and 73.6 +/- 22.3 s in groups I and II, respectively (p < 0.03). During validation of the technique, 54 of 60 patients (90%) had successful left atrial entry through probing. Atrial level shunt was not seen. CONCLUSION: Probing the fossa achieves left atrial entry in 90% of patients. It avoids needle puncture and reduces puncture time as well as fluoroscopy time. It is a safe technique.

Adolescent↗