Accuracy of CO2 angiography in vessel diameter assessment: a comparative study of CO2 versus iodinated contrast material in an aortoiliac flow model.

PURPOSE: Precise vessel sizing prior to endovascular intervention is critical to achievement of technical success. Diameter measurements obtained with CO2 and iodinated contrast material in an aortoiliac flow model were compared. MATERIALS AND METHODS: Aortoiliac flow was simulated in a compliant, silicone elastomer phantom of the aortoiliac system using an autoperfusion pump (flow volume, approximately 1100 mL/min; mean arterial pressure, 70-80 mm Hg at 80-90 cycles/minute) and a glycerol solution (40% by weight; viscosity 3.7 centipoise at 20 degrees C). Digital subtraction angiography was performed with the phantom in the anteroposterior (AP) plane and in three oblique planes with both CO2 and iodinated contrast material. Five sets of images for both CO2 and iodinated contrast material were obtained for each projection. Two readers independently performed vessel diameter measurements at seven sites (distal abdominal aorta, bilateral proximal and distal common iliac, and mid-external iliac arteries). The model was then evaluated with intravascular ultrasound (IVUS) using a 20-MHz imaging catheter. Actual diameter measurements were taken from the inner wall to inner wall in orthogonal planes at the same locations within the model, as described previously. Analysis was performed to determine local difference in measurements (t tests), difference when compared to the standard AP projection with iodinated contrast material (Dunnett's test) and inter-reader variability (Pitman's test). RESULTS: The contralateral iliac vessel segment did not opacify when imaging with CO2 in the 45 degrees obliquities; thus, 22 of 28 sites were available for comparison. At 18 of 22 (81.8%) sites, there was significant difference in vessel measurements (P < .01), with CO2 yielding a significantly larger diameter at 17 of 22 (77.3%) of the sites. The difference in mean diameter ranged from -1.28 to 4.47 mm. With use of the AP iodinated contrast material run as the standard, there were significant differences (P < .05) in vessel diameter at 17 of 22 (77.3%) and four of 21 (19%) sites for CO2 and iodinated contrast material respectively, with CO2 tending toward greater diameter measurements. Significant differences (P < .05) in variance between the two readers were present but occurred primarily with CO2 in the AP projection and iodinated contrast material in the 45 degrees left obliquity. With use of IVUS as the standard, there were significant differences (P < .05) in the measured vessel diameters with CO2 at nine of 22 (40.9%) of the sites and with iodinated contrast material at 17 of 28 (60.7%) of the sites. Of the measurements made with CO2, seven of nine (77.8%) of the measurements were of larger diameter than those obtained with IVUS. By contrast, of the measurements made with iodinated contrast material angiography, IVUS measured larger diameters in 16 of 17 (94.1%). CONCLUSION: CO2 angiography consistently yielded significantly larger vessel measurements when compared to both iodinated contrast angiography and WVUS. These results have important implications in regards to planning intervention based solely on CO2 angiography. Further evaluation is needed before recommending CO2 for vessel sizing in clinical practice.

Hepatic artery embolization: factors predisposing to postembolization pain and nausea.

PURPOSE: Analysis of preprocedural factors that may be helpful in predicting the severity of pain and nausea after hepatic arterial embolization (HAE) for liver neoplasms. MATERIALS AND METHODS: During a 2-year period, 62 patients (33 men, 29 women) underwent 130 palliative lobar HAEs for unresectable liver neoplasms. The hepatic lobe was embolized with 150-250-microm polyvinyl alcohol particulates with or without lipiodol and/or chemotherapeutic agents. Postembolization pain was rated at rest and during movement with use of an 11-point verbal pain scale, and postembolization nausea was assessed with use of a four-point verbal scale, each at two separate time periods. Daily morphine use was also recorded. Primary analysis was made using the first embolization procedure. One-way analysis of variance and Spearman correlation coefficients were used to identify associated predictors. Plots of the outcomes versus the pre-embolization liver function tests and sensitivities and specificities were used to identify the strength of the associations for prediction purposes. A secondary analysis was performed in patients who underwent multiple embolizations. RESULTS: No strong categorical predictors were found from the ANOVA on the severity of postembolization pain or nausea. There were significant (P < .05) associations between the pre-embolization liver function tests and the pain outcomes only. However, while these laboratory values demonstrate strong associations with resultant pain, they are not strong predictors of pain and morphine requirements for any individual patient. The morphine requirements were highly associated (P < .0001) with the pain scores at rest and with movement. The authors did not find significant differences on any of the pain outcomes or morphine requirements between the first and second embolizations. CONCLUSION: Laboratory values and patient age are not predictors for the severity of postembolization pain and nausea. Postembolization pain is a significant complication and poses a continuing challenge to the physician with regards to patient management.

Patients' perception of stopping or continuing treatment of cervical dystonia with botulinum toxin type A.

Despite widespread commercial acceptance of botulinum toxin (BTX) for idiopathic cervical dystonia (ICD), no follow up has been performed to determine when and why some patients stop therapy. It has been suggested that some patients who stop BTX treatment may do so because of permanent improvement. We surveyed 155 patients with ICD who were treated over 6 years with BTX to determine when and why patients stopped treatment with BTX, and what adverse events and changes in dose and/or frequency of treatments occurred in those who continued treatment. Of the 133 (86.6%) individuals returning the surveys, 104 continued on BTX treatment and 29 had stopped therapy. Of the 29 subjects no longer receiving BTX, 11 individuals had only received one or two injections. Prior surgical treatment for ICD did not influence their decision to stop therapy. Of those 104 of 133 continuing on BTX treatments, two thirds of the subjects reported the injections always help, whereas one quarter estimated one set of injections did not help. One third of those continuing treatment reported the first injection was most helpful, whereas another one third felt all injections were similarly effective. After an initial adjustment, BTX dosages and frequency of treatment remained stable in this group.

Brachytherapy for the prevention of stenosis in a canine hemodialysis graft model: preliminary observations.

PURPOSE: To determine whether gamma brachytherapy can prevent in-stent stenosis in hemodialysis grafts. MATERIALS AND METHODS: Six-millimeter polytetrafluoroethylene arteriovenous grafts were created bilaterally in six dogs. After 1 month, Wallstents spanning the venous anastomosis were placed to accelerate restenosis. Gamma irradiation (12 Gy) was delivered endoluminally to one of the two grafts by using an iridium 192 source; thus, each animal served as its own control. Fistulography was performed monthly for 10 months or until graft thrombosis, with measurement of stenosis at each time point. At the conclusion of the study period, the treated area was examined histologically, and a computer model was used to calculate the volume of intimal hyperplasia. RESULTS: Delayed stent migration resulted in exclusion of one dog. In the remaining five dogs; maximum stenosis across all time intervals was less for the treated side (P < .04), and the volume of intimal hyperplasia was less for the treated side (P < .045). In one animal studied at 1 year, this trend reversed in terms of percentage stenosis but not total neointimal volume. CONCLUSION: Brachytherapy with 192Ir (gamma) delivered at the time of stent placement reduces restenosis in this hemodialysis graft model, but, depending on the parameter evaluated (stenosis vs total volume of neointima), the benefit may wane or even reverse with time.

Abdominal and pelvic needle aspiration biopsies: can we perform them well when using small needles?

BACKGROUND: The aim of this study was to compare abdominal fine-needle aspirations (FNAs) performed with large (>/=20-gauge) or small (