SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
A 40-year-old woman presented a 6-week history of "fluttering" in her chest. A diagnosis of bilateral diaphragmatic myoclonus was made by fluoroscopy and electromyography of both hemidiaphragms. No central or peripheral cause was identified, but treatment with intravenous phenytoin had an immediate effect. With therapy, she has been symptom free for 12 months.
In this investigation, we studied the feasibility of 3D-reconstruction from 2D cross-sectional intracoronary ultrasound images. A computer-aided, automated 3D-reconstruction was used to generate cylindrical and sagittal format of vessels in vitro (n = 9) and in vivo (n = 48). Ultrasound 2D-images were acquired with a 20 MHz mechanical intracoronary ultrasound catheter (Boston Scientific). A slow pullback (about 1 mm/s) of the catheter was performed during continuous recording of the ultrasound images. The recorded 2D-images were then fed to an image processing computer. Correction and scaling of the axial vessel dimensions was performed by the assessment of the catheter position in the simultaneously recorded biplane fluoroscopy. Digitized data were then processed to 3D-images with use of voxel space modeling. The 3D-views from any plane can be reconstructed. The in-vitro study demonstrated that the reconstructed images were able to correctly portray the pathological changes of the vessel wall in all specimen as proved by pathologic examination. In the in-vivo study, 3D-reconstruction provided not only a spatial visualization of the coronary arterial disorders (such as coronary aneurysm, coronary dissection, spontaneous plaque rupture etc.) but also provides the potential to quantify the mass of lesions. By combining sagittal and cylindrical views, 3D-reconstruction enables longitudinal and orthogonal imaging of the both the vessel lumen and vessel wall, therefore, it has the advantage of cross-sectional viewing as obtained from intracoronary ultrasound and the longitudinal viewing as derived from coronary angiography. These preliminary results of the study indicate that 3D-reconstruction of coronary segments is a promising technique for studying coronary artery disease. Analysis can be based not only on single or multiple cross-sectional images but also on vessel segments facilitating serial studies as for instance studies assessing the progression and regression of atherosclerosis.
Percutaneous gastrostomy, utilizing a dedicated catheterization kit, with a combination of ultrasonographic (US) and fluoroscopic guidance, was carried out in 27 patients. The main indication for gastrostomy was the need for nutritional support in malignant esophageal stricture. After distending the stomach with water via a nasogastric tube, the gastric antrum was punctured under US guidance and a guide wire was inserted, followed by fluoroscopically guided tract dilatation and insertion of a 2.5-mm Cope-loop catheter. In all patients but one (96%) the procedure was successfully completed in one or 2 attempts. Two complications occurred: one case of a small subcutaneous abscess near the puncture site, and one late incident of dislodgement of a catheter without string-loop fixation, which had been inserted at a catheter exchange after 6 weeks. Percutaneous gastrostomy guided by US and fluoroscopy is a safe and efficacious alternative to endoscopic and surgical gastrostomy.
A retrospective analysis of fluoroscopy-assisted plantar fasciotomy/calcaneal exostectomy is presented. The study included 34 patients whose symptoms were all improved to some degree by the procedure. On a five-point scale, the average improvement of preoperative symptoms was 3.2. There were a total of eight complications. The time it took to return to normal activities and until the pain became less than preoperatively was found to be decreased when compared with traditional methods. This technique, using a single, plantar medial, small incision should be considered as an option in the treatment of recalcitrant plantar fasciitis/heel spur syndrome.
We describe the technique of percutaneous vertebroplasty using methyl methacrylate. We injected under the guidance of CT and fluoroscopy a group of 10 patients with back pain caused by a variety of vertebral lesions including severe osteoporosis (n = 4), hemangiomas (n = 5) and metastasis (n = 1). Over varying periods of follow-up (ranging from 4 to 17 months) none of the injected vertebral bodies demonstrated compression. All patients had relief of back pain; none had complications related to the technique. We emphasize that the efficacy of this technique in preventing vertebral collapse could not be evaluated in this small sample; a well-controlled study would be required to determine the proper indications and efficacy of this treatment.
Endoscopic nasobiliary drainage without the aid of fluoroscopy, as an emergency procedure, was performed successfully in four patients with severe calculous cholangitis. There were no complications. All the patients improved and three were taken for definitive surgery later.
OBJECTIVE: To evaluate the frequency and sites of communication among the antebrachiocarpal, middle carpal, and carpometacarpal joints in cattle. ANIMALS: 137 limbs were obtained from 72 fresh bovine cadavers submitted for necropsy because of problems unrelated to the carpus. PROCEDURE: 1 of the 3 injection sites was randomly assigned to both carpi of each ox, and a mixture of latex and barium sulfate was injected into the joint. Communication between 2 or more joints was determined by the presence of latex and contrast material in a joint adjacent to the injected joint by examination of frozen sections, positive-contrast arthrography, and fluoroscopy. RESULTS: Communication existed among the 3 joints in 18 specimens (13.1%). The middle carpal joint and the carpometacarpal joint always communicated. The antebrachiocarpal joint communicated with the middle carpal joint between the ulnar and intermediate carpal bones. The middle carpal and carpometacarpal joints always communicated between the fourth and fused second and third carpal bones. In a few specimens, additional sites of communication were identified at the palmar aspect of the fourth carpal bone and the fused second and third carpal bones. CONCLUSIONS AND CLINICAL RELEVANCE: Individual anatomic variation of the carpus in cattle should be considered when diagnostic or treatment protocols are established.
A new CT system that permits real-time monitoring of CT images was developed. Phantom and volunteer studies revealed that the images were displayed at a rate of six per second with a delay time of 0.83 second with clinically sufficient resolution (256 x 256) using the newly developed fast image processor and partial-reconstruction algorithm. The clinical trial of stereotactic aspiration of intracerebral hematoma was successful. The initial trial with CT fluoroscopy revealed potential usefulness of the system in biopsy and other CT-guided interventions.
Breast cancer has occurred in excess among women exposed briefly to atomic bomb radiation and among those exposed repeatedly over many years to medical radiation for tuberculosis (TB). The excess relative risk of breast cancer incidence in the Japanese atomic bomb survivors, however, is significantly higher (two-sided P = 0.04) than that in the Massachusetts TB fluoroscopy patients. The best estimate of the ratio between the excess relative risk coefficients for the Japanese and Massachusetts cohorts is 2.11 (95% CI 1.05, 4.95). However, this higher relative excess risk is attributable to the lower baseline risk of breast cancer among Japanese women compared with the Massachusetts women, and the excess absolute breast cancer risks in the two data sets are statistically indistinguishable (two-sided P = 0.32). The best estimate of the ratio between the excess absolute risk coefficients among Japanese and Massachusetts women is 0.73 (95% CI 0.41, 1.44). After childhood exposures, an early onset of radiation-induced breast cancer was seen among Japanese atomic bomb survivors but not among the Massachusetts women. There are some indications (two-sided P = 0.04) of differences in the patterns of risk over time since exposure between these groups exposed in childhood. However, in general there are no marked differences between the Massachusetts and Japanese data sets in the age and time distribution of risk of radiation-induced breast cancer. These data provide little evidence for a reduction of breast cancer risk after fractionated irradiation.
UNLABELLED: Epidural steroids are commonly administered in the treatment of "failed back surgery syndrome." Because patient response is dependent on accurate steroid placement, fluoroscopic guidance has been advocated. However, because of ever-increasing medical expenditures, the cost-benefit of routine fluoroscopy should be critically evaluated. Therefore, 50 patients were enrolled into this institutional review board-approved, prospective, controlled, single-blinded study. At a predetermined intervertebral level, the epidural space was identified using an air loss of resistance technique. Thereafter, an epidural catheter was inserted 2 cm through the epidural needle. To determine the accuracy of the clinical placement, contrast medium was administered through the epidural catheter; antero-posterior and lateral lumbar spine radiographs were then obtained. The number of attempts required to successfully locate the epidural space, the reliability of the air loss of resistance technique in indicating successful epidural penetration in failed back surgery syndrome, the ability of the clinician to accurately predict the intervertebral space at which the epidural injection was performed, and the spread of contrast medium within the epidural space were recorded. A total of 48 epidurograms were performed. The number of attempts to successfully enter the epidural space was 2 +/- 1. In 44 cases, the radiological studies confirmed the clinical impression that the epidural space had been successfully identified. In three patients, the epidural catheter was in the paravertebral tissue. One myelogram was recorded. In 25 patients, the epidural catheter did not pass through the predetermined intervertebral space. In 35 cases, the contrast medium did not reach the level of pathology. IMPLICATIONS: The clinical sign of loss of resistance is a reliable indicator of epidural space penetration in most cases of "failed back surgery syndrome." However, surface anatomy is unreliable and may result in inaccurate steroid placement. Finally, despite accurate placement, the depot-steroid solution will spread to reach the level of pathology in only 26% of cases.
Percutaneous placement of an inferior vena cava filter is a means for long-term prevention of pulmonary thromboembolism. In this study we investigated the magnetic resonance (MR) imaging properties of a Nitinol vena cava filter, in various anatomic and angiographic scans, as well as the feasibility of placing this filter under near real-time, high-resolution MR fluoroscopy. We made use of the passive tracking strategy, with on-line image processing and visualization, both in vitro and in a pig. The artifacts provoked by the metallic filter were such that the position and orientation of the filter were well depicted in all scans. Considerable radiofrequency caging obscured the interior of the filter. Our experiments showed that an MR-guided vena cava filter placement, with sufficient temporal and spatial resolution, is possible. Three-dimensional phase contrast MRA allowed direct evaluation of the filter placement procedure, without the use of contrast agent.
BACKGROUND: This study was undertaken to evaluate the potential benefits of using an electromagnetic detection system to guide the intraoperative placement of chronic venous access devices (CVADs). STUDY DESIGN: An electromagnetic detection system was used to guide catheter placement during 54 procedures. Surgery and radiation exposure times were recorded. An oncology nursing follow-up questionnaire assessed device function. A cost analysis was performed. Outcomes were compared to similar data from a fluoroscopic historical control group. RESULTS: Eight study patients required intraoperative fluoroscopy; in 46 procedures (85%) the electromagnetic detection system was the sole modality employed to guide CVAD placement. One line was subsequently found in the internal mammary vein (2% false negative rate). Mean surgery times for placement of CVADs were 79.5 and 84.5 minutes for the study and control groups (p = NS). Mean radiation exposure rates were 0.16 and 0.86 minutes per patient for the study and control groups (p < 0.01). There was no significant difference in device function between groups. Major complications in the study group were rare. Mean cost of CVAD placement was $1993 and $2517 for the study and control groups (p = 0.005), respectively. CONCLUSIONS: The use of the electromagnetic detection system resulted in accurate placement of chest wall CVADs in the majority of patients. This resulted in significant reductions in radiation exposure and cost of CVAD placement.
We examined the efficacy of percutaneous cervical cordotomy (PCC) and subarachnoid phenol block using fluoroscopy (SAPB-F) for control of chest and/or back pain from costopleural syndrome. The efficacy of each block was evaluated by changes in pain score (PS), analgesic dose and performance status 1 week after the block, as well as by the complications. Between 1980 and 1986, PCC was performed in 10 patients. SAPB-F was performed in 13 patients between 1987 and 1991. Pain was not well controlled by analgesics in any of these patients. For PCC the follow-up period was 94.7 +/- 71.1 days. PS (VAS, 0-10) reduced from 8.5 +/- 0.9 to 3.0 +/- 2.7. No analgesics were needed in 4 patients. Pain recurred in 1 patient. Hemiparesis occurred in 2 patients. General fatigue occurred in 6 patients. In 4 patients with these complications performance status deteriorated and did not recover during the follow-up period. For SAPB-F the follow-up period was 71.8 +/- 44.0 days. SAPB-F was designed to achieve selective phenol deposit at the targeted nerve root. PS decreased from 7.5 +/- 1.9 to 2.7 +/- 2.6. No analgesics were needed in 5 patients. Pain recurred in 3 patients. There were no complications and no changes in performance status. From this study we concluded that PCC is an effective method of pain control for costopleural syndrome, but a risk of serious complications is involved. SAPB-F is an effective and safe method and should be the first choice of nociceptive pathway block.
Prosthetic heart valve thrombosis (PVT) is a rare but potentially life-threatening complication of heart valve replacement. An effective, quick, and easy diagnostic method is highly desirable. We evaluated the diagnostic efficacy of cine-fluoroscopy (CF), transthoracic (TTE), and transesophageal (TEE) echocardiography in 82 consecutive patients with mechanical valves and suspected PVT. Criteria for PVT were: leaflet(s) motion restriction at CF, increased Doppler gradients at TTE, and evidence of thrombi at TEE. Patients were divided in 4 groups (A, B, C, and D) according to results of CF and TTE. Group A was composed of 24 patients with positive CF and TTE. Thrombi were detected by TEE in all cases, suggesting that when both are positive, CF and TTE correctly identified PVT in all patients so that TEE may be deferred. Group B was composed of 12 patients with positive CF and negative TTE; TEE showed PVT in 4 patients (33%). These patients had very slight leaflet motion restriction as in the case of initial PVT. This suggests that CF compared with Doppler may identify patients with "hemodynamically significant" PVT. The remaining 8 patients in this group had monocuspid prostheses with negative TEE, suggesting that abnormal leaflet motion at CF may be due to functional changes. Therefore, TEE should always be performed in case of monocuspid prostheses with isolated CF abnormalities. Group C was composed of 18 asymptomatic patients with small-sized aortic prostheses and very high Doppler gradients on routine TTE. CF showed normal leaflet motion and TEE ruled out PVT in all cases outlining the diagnostic role of CF in this particular subset. Finally, group D was composed of 28 patients with negative CF and TTE. TEE did not show thrombi in 24 of 28 patients (86%), confirming that, when both yield negative results, CF and TTE are reliable methods to rule out valve thrombosis in most cases. However, in 4 of 28 patients (14%) TEE showed "nonobstructive" prosthetic thrombosis: these patients had mitral prostheses, chronic atrial fibrillation, and 3 of 4 had systemic embolisms. Thus, TEE should be performed in selected patients despite negative CF and TTE results. Sensitivity, specificity, and positive and negative predictive values were 87%, 78%, 80%, and 91% for CF and 75%, 64%, 57%, and 78% for TTE, respectively. CF and TTE correctly identified PVT in 70 of 82 patients (85%). TEE was actually required in 15% of the cases. Thus, CF and TTE are quick, effective, and complementary diagnostic tools to diagnose PVT in most patients. TEE still remains the gold standard technique in selected cases.
A new direct anatomic two-incision approach for total hip replacement without the use of fluoroscopy is described. The anterior incision is the distal one third of a Smith-Peterson approach and the posterior incision is the proximal one third of the Moore approach. It has been used on 142 unselected consecutive.
Interventional devices used in radiology often have dimensions on the order of a pixel, and radiologists resort to image magnification to better visualize such small devices. Traditional image intensifier (II) systems use analog magnification with x-ray exposure inversely proportional to the area of field of view (FOV) so as to maintain light output for the camera. Analog magnification is impossible with flat panel (FP) detectors, and images must be magnified using digital interpolation that does not reduce the pixel partial area effect for small devices. We quantitatively investigated image quality of digital and analog magnification using a clinically relevant task of detecting a partially deployed stent in x-ray fluoroscopy image sequences that were created using realistic detector models. Using the standard exposure strategy for II analog magnification, exposure was increased from a nominal 43.65 nGy (5.0 microR) per frame at 23 cm FOV to 79.9 nGy (9.15 microR) per frame and 117.81 nGy (13.49 microR) per frame at 17 cm and 14 cm FOV, respectively. Contrast sensitivity improved significantly (p<0.1) by 43.5+/-6.5% and 64.1+/-7.3% with the 17 cm and 14 cm FOV, respectively. Exposure for digitally magnified images was varied in an adaptive forced choice experiment so as to match performance with II analog magnification. For digital magnification, bilinear interpolation was used to give magnified stents sizes equivalent to those in the analog magnified images. For equivalent image quality, FP required 34.87+/-2.59, 80.16+/-5.37, and 84.08+/-5.59 nGy per frame at normal, and the two magnification modes, respectively. Hence, FP with digital magnification gives significant (p<0.1) dose savings of 20+/-6% and 27+/-5% at the normal and highest magnification modes, respectively. Digitally magnified II images required exposures of 110.85+/-8.07 and 103.34+/-5.90 nGy per frame for the two magnifications levels, respectively, giving no significant (p>0.1) dose savings. A spatiotemporal human observer model based on signal detection theory successfully predicted the human data and was used to predict other conditions associated with image magnification. Model predictions quantitatively showed that magnification is most useful when signal size is relatively small and that FP digital magnification can improve image quality for the stent deployment task without increasing exposure. In conclusion, the results show that FP digital magnification can be useful and dose efficient as compared to analog magnification.
The authors have investigated the effect of 5 frames/s television fluoroscopy on the time required to selectively catheterize five test arteries in an angiographic phantom. Here, 5 frames/s acquisition was accomplished by sampling frames from a 30 frames/s video signal. Sampled frames were stored in a video memory which provided continuous display to the fluoroscopist between samples. The test phantom was a plastic model of an aorta with branching vessels immersed in an isodense suspension of barium in water. For four of the five vessels there was no significant difference in time required for catheter placement between 30 frames/s and 5 frames/s.
BACKGROUND: Tracheobronchial stenting is performed increasingly often. Fluoroscopic control, which leads to significant radiation exposure for patients and staff, is recommended for the placement of metal stents. METHODS: All consecutive patients referred to two airway centers in need of airway stenting who received stents (Ultraflex; Boston Scientific, Natick, MA) underwent placement using endoscopic guidance only. All data were collected in an ongoing continuous database. RESULTS: One hundred stents were placed in 96 patients for central airway obstruction, and the data were reviewed. Stents were placed in all locations within the central airways for a variety of indications but mainly for malignant obstruction. No complications occurred, and all stents were placed satisfactorily. CONCLUSION: At centers with dedicated airway teams, Ultraflex stents can be quickly and safely inserted without the need for fluoroscopy. This saves radiation exposure to patients and to staff and may lead to a more cost-effective procedure.