Radiation Exposure and Contrast Agent Reduction During Transcatheter Aortic Valve Implantation: An Ongoing Experience.

OBJECTIVES: To determine the patient radiation exposure and contrast agent variation during transcatheter aortic valve implantation (TAVI) procedures resulting from technological improvements. METHODS: TAVI procedures from January 2008 to July 2015 were analyzed in three different time periods: 1st period, when the angiography was equipped with an image intensifier technology; 2nd period, starting with the installation of a new angiography system with flat-panel detector (FPD) technology; and 3rd period, starting with the systematic use of preprocedural multidetector computed tomography (MDCT) to individualize optimal fluoroscopic projections for the aortic prosthesis implantation. RESULTS: Significant differences were found in contrast volume (198 ± 99 mL vs 139 ± 74 mL; P<.001), kerma area product (211 ± 135 Gy•cm² vs 147 ± 120 Gy•cm²; P<.001) and effective dose (42 ± 27 mSv vs 29 ± 24 mSv; P<.001) between the 1st and 2nd periods, respectively. The reduction continued between the 2nd and 3rd periods for contrast volume (139 ± 74 mL vs 110 ± 61 mL; P<.001), kerma area product (147 ± 120 Gy•cm² vs 111 ± 69 Gy•cm²; P<.001), and effective dose (29 ± 24 mSv vs 22 ± 11 mSv; P<.001), respectively. CONCLUSIONS: The present study suggests that the appropriate use of FPD technology and preprocedural MDCT to individualize fluoroscopic implant projections for TAVI temporally reduced the amount of radiation and contrast agent administered over time.

[Development of Digital Subtraction Angiography Method for Pediatric Cardiac Angiography Using Subtraction Technique with Heart Rate].

Digital subtraction angiography (DSA) has been used in head and abdomen. However, in recent years, the use of cardiac DSA has been reported. In this report, we discuss the development of a DSA method with heart rate to clearly visualize blood vessels of pediatric patients. The patients included five children who underwent pulmonary artery angioplasty. We used a process to resize the original images and performed two kinds of subtraction methods as well as visually evaluated the images and performed comparisons between pairs of images using the Scheffe's method. Subtraction techniques were used to eliminate motion artifacts of the heart, thoracic vertebra, ribs, and diaphragm. Visualization of the image of blood vessels of pulmonary arteries using the subtraction technique with heart rate was superior to the visualization of the conventional DSA images of peripheral blood vessels of the lung and pulmonary arteries. Use of subtraction technique with heart rate makes it possible to obtain more detailed information on pediatric cardiac angiography images noninvasively.

Dosimetry of Pediatric PET/CT.

The use of PET/CT in children has grown substantially in the past few years. There is also an increased interest in keeping the radiation dose to children from CT as low as is clinically practical. This article reviews the physical aspects of both PET and CT separately and how CT is used in the context of PET/CT to provide the practical insight necessary to approach this issue. Understanding radiation dosimetry and its potential for deleterious health effects, having knowledge of the magnitude of the effective dose and the dose to specific organs from PET and CT, and considering the role of CT in the context of PET/CT will allow the reader to reduce the radiation dose to the patient without compromising the quality of the patient's care.

What technical barriers exist for real-time fluoroscopic and video image overlay in robotic surgery?

BACKGROUND: A hypothetical advantage of the da Vinci console is its ability to integrate multiple visual data sources. Current platforms for augmented reality surgery fuse pre-operative radiographic studies but are limited with their ability to update with intra-operative imaging. The aim of our study was to evaluate the feasibility of real-time radiographic image overlay with current technology. METHODS: S-video composite output from a fluoroscopic C-arm was superimposed onto the video output of the da Vinci device. Image superimposition disparity measurements were evaluated in a bench model. The feasibility of robotic dissection assisted by real-time cholangiogram and intravenous pyelogram was evaluated. RESULTS: Image alignment resulted in a radiographic blind spot and image disparity with severely limited application in an in vivo model. CONCLUSIONS: External collisions of the robotic device and visual disparity in multiple planes negate the current implementation of fluoroscopic overlay and will require more elegant methods of computer-assisted registration.

[Complications of intravenous digital subtraction angiography--results in 500 patients]. / Komplikationen der IV-DSA--Ergebnisse bei 500 Patienten.

500 patients were studied respectively for complications of intravenous digital subtraction angiography (IV-DSA) performed with non-ionic contrast media, using a central venous injection technique. In 21 patients (4.2%) during or shortly after the procedure 23 systemic, 1 neurologic, and 7 local complications occurred. In addition 1 patient developed acute renal failure 26 hours after the IV-DSA, whereas 4 patients later showed on thromboses of the catheterised vein. No permanent neurologic or systemic complications and severe allergic reactions were seen.

Utility of DSA in the evaluation of haemodialysis access fistulas.

Results of 39 intravenous and intraarterial DSA studies of haemodialysis access fistula are presented. Advantages of DSA versus conventional fistulography and xeroangiography are discussed. Digital subtraction angiography represents an accurate, time-saving and low complication approach to the evaluation of failing dialysis access fistulas.

Somatic and genetic radiation exposure of the patient in digital subtraction angiography (DSA)

The somatic and genetic radiation exposure of patients undergoing Digital Subtraction Angiography (DSA) and traditional Film Arteriography (FA) of cranial, cervical, thoracic and abdominal vascular territories are compared. The radiation doses absorbed within the critical organs--red bone marrow, lung, thyroid gland and female breast--and in the gonads were measured using an anthropomorphic Alderson phantom. A Somatic Dose Index was calculated in order to estimate the somatic radiation risk. The somatic radiation exposure depends upon the location of the critical organs with respect to the entrance site of the x-ray beam, and can be reduced by an appropriate choice of the angiographic projection. Under this condition, the radiation exposure of the patient during DSA can be lower than during FA. For renal DSA an a.p. projection, the use of an abdominal compression device and careful caudal shielding of the field are advocated.

Carotid digital subtraction angiography: the comparative roles of intra-arterial and intravenous imaging.

Intravenous digital subtraction angiography (IV DSA) has assumed a major role in the evaluation of occlusive cerebrovascular disease. However, an increasing incidence of inadequate and inaccurate IV DSA studies led us to use intra-arterial DSA (IA DSA) with greater frequency in the assessment of carotid artery disease. This study was performed to establish the optimal role of these two procedures in the diagnosis and management of carotid atherosclerosis. One hundred forty-eight patients who underwent carotid endarterectomy were assessed before operation with IV DSA (54 patients), IA DSA (41 patients), or conventional angiography (CA) (53 patients). Studies were reviewed for technical adequacy, extent of carotid visualization, contrast volume, incidence of complications, and necessity for further angiography. Subsequently the endarterectomy specimen was used to determine the accuracy of each imaging technique. The accuracy of IA DSA (94%) was significantly greater than that of IV DSA (68%) and no less than that of CA (97%) (p less than 0.0005). Only two IA DSA studies were technically inadequate (4%) compared with 26 of 65 (40%) IV DSA studies (p less than 0.0005). IA DSA consistently required less contrast agent (88 ml versus 144 ml) than did IV DSA (p less than 0.0005) but the extent of vessel visualization was greater. There was no difference in the complication rates of IV DSA and IA DSA, but both were less than that of CA (p less than 0.05). These data show IA DSA to be superior to IV DSA in the evaluation of carotid artery disease. IA DSA is now our preferred method of study and has increasingly supplanted CA techniques as well.