Performance of Creatinine Clearance and Estimated GFR in Assessing Kidney Function in Living Donor Candidates.

BACKGROUND: Glomerular filtration rate (GFR) assessment is a key aspect in the evaluation of living kidney donor candidates; however, data on performance of commonly used methods are limited. METHODS: We examined 769 living kidney donor candidates with 24-hour urine collections assessed as accurate by comparing measured creatinine excretion rate (CER) to CER estimated using a 4-variable equation previously developed and validated using robust methodology. RESULTS: Of all collections, 42.6% would have been deemed inaccurate, mostly under-collections, using the conventional weight- and gender-based CER estimation. Creatinine clearance (CrCl) overestimated I-iothalamate GFR (iGFR), estimated GFR (eGFR), underestimated iGFR, and their average [Avg (CrCl and eGFR)] essentially eliminated the GFR bias (median bias = +2.2, -5.4, and -1.0 mL/min/1.73 m, respectively; P < 0.001). This held true for all subgroups except blacks, where all 3 measures overestimated iGFR. Avg (CrCl and eGFR) also offered modestly improved accuracy compared with CrCl alone, as measured by the proportion of values falling within 10% (50.7% versus 45.3%; P = 0.009) and 30% of iGFR (94.5% versus 89.3%; P < 0.001). CONCLUSIONS: When measured GFR is unavailable, the Avg (CrCl and eGFR) provides a better estimate of kidney function in kidney donor candidates than either measure alone, although in blacks the estimates are neither better nor worse.

Extracellular acidosis differentiates pancreatitis and pancreatic cancer in mouse models using acidoCEST MRI.

Differentiating pancreatitis from pancreatic cancer would improve diagnostic specificity, and prognosticating pancreatitis that progresses to pancreatic cancer would also improve diagnoses of pancreas pathology. The high glycolytic metabolism of pancreatic cancer can cause tumor acidosis, and different levels of pancreatitis may also have different levels of acidosis, so that extracellular acidosis may be a diagnostic biomarker for these pathologies. AcidoCEST MRI can noninvasively measure extracellular pH (pHe) in the pancreas and pancreatic tissue. We used acidoCEST MRI to measure pHe in a KC model treated with caerulein, which causes pancreatitis followed by development of pancreatic cancer. We also evaluated the KC model treated with PBS, and wild-type mice treated with caerulein or PBS as controls. The caerulein-treated KC cohort had lower pHe of 6.85-6.92 before and during the first 48 h after initiating treatment, relative to a pHe of 6.92 to 7.05 pHe units for the other cohorts. The pHe of the caerulein-treated KC cohort decreased to 6.79 units at 5 weeks when pancreatic tumors were detected with anatomical MRI, and sustained a pHe of 6.75 units at the 8-week time point. Histopathology was used to evaluate and validate the presence of tumors and inflammation in each cohort. These results showed that acidoCEST MRI can differentiate pancreatic cancer from pancreatitis in this mouse model, but does not appear to differentiate pancreatitis that progresses to pancreatic cancer vs. pancreatitis that does not progress to cancer.

Success Rate of Intra-articular Sacroiliac Joint Injection: Fluoroscopy vs Ultrasound Guidance-A Cadaveric Study.

BACKGROUND: Given the unacceptably high miss rates of non-image-guided injections into the sacroiliac joint, either fluoroscopy or ultrasound is recommended for guidance. The real success rate of both techniques was assessed by cadaver dissection. METHODS: Twenty bodies donated to science (40 joints: 15 female and 5 male) were investigated bilaterally. Fluoroscopy and a lower ultrasound-guided approach were performed in 10 bodies each. Conditions during puncture, the subjective feeling of the needle being intra-articular, and, for fluoroscopic guidance, the intra-articular spread of the contrast were assessed. First, 0.5 cc of Iopamidol was injected, followed by 2 mL of red-colored latex. The spread was investigated by dissection via anterior opening of the sacroiliac joint and the dorsal ligaments. RESULTS: Ultrasound guidance was used in 1/20 (5%, 95% CI = 0.9-23.6%) intra-articular injections. In 19/20 (95%, 95% CI = 0.9-23.6%) cases, latex spread in the interosseous sacroiliac ligament was used. Conditions of structural visibility were classified as good in 11/20 (55%, 95% CI = 34.2-74.2%) cases, puncture condition as good in 16/20 (80%, 95% CI = 58.4-91.9%) cases, and subjective feeling of the needle being intra-articular was present in 10/20 (50%, 95% CI = 34.2-74.2%) cases. Fluoroscopy showed an intra-articular injection in 10/20 (50%, 95% CI = 34.2-74.2%) cases. The structure visibility in fluoroscopy was good in 9/20 (45%, 95% CI = 25.8-65.8%), puncture conditions good in 8/20 (40%, 95% CI = 21.9-61.3%), intra-articular contrast spread visible in 10/20 (50%, 95% CI = 34.2-74.2%), and subjective feeling of being intra-articular was present in 17/20 (85%, 95% CI = 64.0-94.8%) cases. CONCLUSIONS: Fluoroscopy clearly showed a higher success rate of intra-articular sacroiliac joint injection.

Oil-based or water-based contrast for hysterosalpingography in infertile women: a cost-effectiveness analysis of a randomized controlled trial.

OBJECTIVE: To determine the cost effectiveness of the use of oil-based versus water-based contrast in infertile women undergoing hysterosalpingography (HSG). DESIGN: Economic evaluation alongside a multicenter randomized trial. SETTING: Hospitals. PATIENT(S): Infertile women with an ovulatory cycle, 18-39 years of age, low risk of tubal pathology. INTERVENTION(S): Use of oil-based versus water-based contrast during HSG. MAIN OUTCOME MEASURE(S): Costs per additional ongoing pregnancy and per live birth within 6 months of randomization, incremental cost-effective ratios (ICERs). RESULT(S): A total of 1,119 women were randomized to HSG (oil-based contrast, n = 557; water-based contrast, n = 562). After HSG, most women had no additional treatment; a minority had IUI or IVF. In the oil group, 39.7% women had an ongoing pregnancy within 6 months of randomization versus 29.1% women in the water group. There was a 10.7% increase in the live birth rate in the oil group. For ongoing pregnancy, the mean costs per couple were US$2,014 in the oil group and US$1,144 in the water group, with a corresponding ICER of US$8,198 per additional ongoing pregnancy. For live birth, the mean costs per couple were US$11,532 in the oil group and US$8,310 in the water group, with a corresponding ICER of US$30,112 per additional live birth. CONCLUSION(S): Hysterosalpingography with oil-based contrast results in higher 6-month ongoing pregnancy and live birth rate. If society is willing to pay US$8,198 for an additional ongoing pregnancy, HSG with oil-based contrast is a cost-effective strategy compared with HSG with water-based contrast for infertile, ovulatory women at low risk for tubal pathology. CLINICAL TRIAL REGISTRATION NUMBER: Dutch Trial Register, NTR 6577 (www.trialregister.nl).

Prospective comparison of gadoxetic acid-enhanced liver MRI and contrast-enhanced CT with histopathological correlation for preoperative detection of colorectal liver metastases following chemotherapy and potential impact on surgical plan.

OBJECTIVE: To prospectively compare the diagnostic performance of gadoxetic acid-enhanced MRI (EOB-MRI) and contrast-enhanced CT (CECT) for preoperative detection of colorectal liver metastases (CRLM) following chemotherapy and to evaluate the potential change in the hepatic resection plan. METHODS: 51 patients with CRLM treated with preoperative chemotherapy underwent liver imaging by EOB-MRI and CECT prospectively. Two independent blinded readers characterized hepatic lesions on each imaging modality using a 5-point scoring system. 41 patients underwent hepatic resection and histopathological evaluation. RESULTS: 151 CRLM were confirmed by histology. EOB-MRI, compared to CECT, had significantly higher sensitivity in detection of CRLM ≤1.0 cm (86% vs. 45.5%; p < 0.001), significantly lower indeterminate lesions diagnosis (7% vs. 33%; p < 0.001) and significantly higher interobserver concordance rate in characterizing the lesions ≤1.0 cm (72% vs. 51%; p = 0.041). The higher yield of EOB-MRI could have changed the surgical plan in 45% of patients. CONCLUSION: Following preoperative chemotherapy, EOB-MRI is superior to CECT in detection of small CRLM (≤1 cm) with significantly higher sensitivity and diagnostic confidence and interobserver concordance in lesion characterization. This improved diagnostic performance can alter the surgical plan in almost half of patients scheduled for liver resection.

[Unilateral periocular angioedema after application of contrast agent]. / Einseitiges periokuläres Angioödem nach Kontrastmittelgabe.

This article presents a case report of unilateral, periocular angioedema after intravenous application of a contrast agent with a temporary increase of intraocular pressure in an eye in which trabeculectomy had been carried out 5 weeks previously.

DEVELOPING A TECHNIQUE FOR ULTRASOUND-GUIDED INJECTION OF THE ADULT CANINE HIP.

An accurate method for guiding injections into the canine hip would facilitate diagnostic localization of lameness and targeted treatments. Ultrasound-guided hip injections are commonly used in humans and large animals. Aims of this prospective study were to describe ultrasound (US) anatomy of the adult canine hip and determine the feasibility and accuracy of intra-articular placement of injectate using US-guidance. Seven adult dogs were used to describe US anatomy, five dog cadavers were used to assess the feasibility of the injection technique and 11 dog cadavers were used to assess accuracy of injections. For the accuracy test, 22 joints were injected with iodinated contrast medium by three operators with different experience. With dogs in lateral recumbency, the hyperechoic femoral head surface was identified by following the femoral neck from the greater trochanter or the acetabular rim was localized by following caudally the ilium from the iliac wing. An anechoic gap between the femoral head and acetabular surface represented the joint. The capsule was visible as a triangular echoic structure and the femoral head articular cartilage appeared as an anechoic band. The needle was inserted axial to the greater trochanter and directed in a dorsolateral-ventromedial direction toward the joint space and then pushed through the capsule. Based on postinjection radiography, accuracy was 81.8% at first attempt and 100% at second attempt. This study indicated that US-guided injection is a feasible and accurate technique for injecting the adult canine hip. Future studies in live dogs are needed to assess safety and efficacy.

Low-contrast agent dose dual-energy CT monochromatic imaging in pulmonary angiography versus routine CT.

OBJECTIVE: This study aimed to retrospectively evaluate the feasibility and reliability of low-contrast agent dose dual-energy computed tomography (DECT) monochromatic imaging in pulmonary angiography. METHODS: Computed tomography pulmonary angiography was performed in 86 patients, 41 in 120-kVp computed tomography (CT) and 45 in DECT with low-contrast agent dose. The images in DECT were reconstructed at optimal kiloelectron-voltage (keV), demonstrating the best contrast-to-noise ratio between pulmonary artery and soft tissue, and at 70 keV. Image quality was compared by quantitative and subjective indexes. The radiation doses were recorded. RESULTS: Compared with 120-kVp CT, optimal keV showed superior quantitative indexes with inferior subjective image quality, whereas 70 keV demonstrated no statistical difference in quantitative indexes with superior subjective image quality. All suspicious pulmonary embolisms in DECT were diagnosed confidently by combination of 2 kinds of monochromatic imaging. The radiation dose in DECT is almost twice as 120-kVp CT. CONCLUSIONS: Low-contrast agent dose DECT monochromatic imaging in pulmonary angiography accommodates superior intravascular enhancement and contrast in pulmonary arteries, and improves diagnostic confidence with compatible radiation dose.

Time- and dose-dependent cytotoxicities of ioxitalamate and indigocarmine in human nucleus pulposus cells.

BACKGROUND CONTEXT: Ioxitalamate (Telebrix 300) is an ionic iodinated contrast medium commonly used for discography or percutaneous endoscopic lumbar discectomy (PELD), though it has side effects such as anaphylactic shock and renal toxicity. Indigocarmine is an organic compound dye with a distinctive blue color that is commonly used during PELD to stain the acidic, degenerated nucleus pulposus (NP). Although ioxitalamate and indigocarmine are widely used in spinal surgery, there have been no reports on their effects on NP cells. We studied the toxicities of both ioxitalamate and indigocarmine to NP cells. PURPOSE: To determine the toxicities of both ioxitalamate and indigocarmine to NP cells in vitro. STUDY DESIGN: In vitro, controlled study of the toxicities of both ioxitalamate and indigocarmine to human NP cells. METHODS: Nucleus pulposus cells were obtained via discectomy from lumbar disc patients and isolated. Nucleus pulposus cells were cultured in three-dimensional (3D) alginate beads with 0.001, 0.1, 10, and 100 mg/mL ioxitalamate, 0.00001, 0.001, 0.1, and 10 mg/mL indigocarmine, or a mixture of both for 1, 2, or 3 days. The living cells were analyzed with trypan blue staining. Fluorescence Activated Cell Sorting analysis using Annexin V and propidium iodide and 3D alginate bead immunostaining was performed to identify live, apoptotic, and necrotic cells. RESULTS: Ioxitalamate, indigocarmine, and their combination induced statistically significant NP cell injury that was both time- and dose dependent (p<.05). Also, at the same concentration, ioxitalamate was more cytotoxic than was indigocarmine or the combination (p<.05). All three treatments also showed dose-dependent cytotoxicity according to flow cytometry and immunostaining. CONCLUSIONS: Ioxitalamate and indigocarmine are toxic to human NP cells in vitro in a time- and dose-dependent manner. We assume that ioxitalamate and indigocarmine may have similar effects in patients undergoing discography and PELD. Thus, we suggest that ioxitalamate and indigocarmine should be used carefully at low concentrations.

Feasibility of using automated insufflated carbon dioxide (CO2) for luminal distension in 3.0T MR colonography.

PURPOSE: Primary aim of our study was to prospectively evaluate the feasibility of automated carbon dioxide (CO(2)) delivery as luminal distending agent in 3.0T MR colonography. MATERIALS AND METHODS: Rectally insufflated CO(2) was evaluated in four groups with different bowel preparation (A-D). Bowel preparation regimes were: gadolinium-based tagging (A), bowel purgation (B), barium-based tagging (C) and iodine-based tagging (D). Supine (3D)T1w-FFE and (2D)T2w-SSFSE series were acquired. Each colon was divided into six segments (cecum S1-rectum S6). Two observers independently assessed the presence of artefacts, diagnostic confidence and segmental colonic distension. Also characteristics of the residual stool (presence, composition and signal-intensity) were assessed per segment. Discomfort was assessed with questionnaires. RESULTS: Fourteen healthy subjects were included. Colonic distension by means of rectally insufflated CO(2) was not associated with susceptibility artefacts. Overall image quality was affected by the presence of bowel motion-related artefacts: none of the segments in 3DT1w-series and 10/84 (12%) colon segments in 2DT2w-series were rated artefact-free by both observers. Diagnostic confidence ratings were superior for the 2DT2w-SSFSE series. Overall bowel distension was rated adequate to optimal in 312/336 (93%) colon segments. CONCLUSION: MR colonography at 3.0T using carbon dioxide (CO(2)) for colonic distension is technically feasible. The presence of intraluminal CO(2) did not result in susceptibility artefacts, although overall image quality was influenced by artefacts.

Comparison of combined oral and i.v. contrast-enhanced versus single i.v. contrast-enhanced mdct for the detection of acute appendicitis.

OBJECTIVE: The aim of our study was to compare the diagnostic ability of oral added intravenous (IV) contrast-enhanced multidetector computed tomography (MDCT) versus only IV contrast-enhanced MDCT in diagnosing of acute appendicitis. MATERIALS AND METHODS: MDCT images of 200 patients were evaluated prospectively in this study. Patients were randomized into one of two groups: Group 1 (Gp1) patients underwent 16-MDCT performed with oral and IV contrast-enhanced and Group 2 (Gp2) subjects underwent 16-MDCT with only IV contrast-enhanced protocol. Final decision was based on histopathologic operative data and follow-up of patients. RESULTS: In Gp1, Reader1 had 96.9% and 98.5% and Reader2 had 84% and 94.7% sensitivity and specificity values respectively. For Gp2, the values for Reader1 were 81% and 94%. For Reader2 in Gp2, the values were 76% and 91%. We achieved higher sensitivity and specificity values with combined contrast administration versus only IV contrast-enhanced MDCT imaging. However, there was no statistically significant differences between two readers in the AUC values of each group for the detection of acute appendicitis. CONCLUSION: It is statistically concluded that oral contrast do not contribute to the a better accuracy. So in the routine practice, oral contrast has not to be recommended.

Accuracy of intra-articular injection of the glenohumeral joint: a modified anterior approach.

PURPOSE: This study examined the accuracy of our modified anterior approach to the glenohumeral joint using arthrography. METHODS: Two hundred fifty-six consecutive patients with adhesive capsulitis received the glenohumeral joint injection: a mixture of 1 mL of 40 mg of triamcinolone hexacetonide, 2 mL of 2% lidocaine, 3 mL of contrast medium (Ioxitalamate), and 4 mL of normal saline solution, for a total of 10 mL, through a modified anterior approach. Anteroposterior, lateral, and axial arthrography after each injection was performed to determine the accuracy and patterns of the injection. The injection was judged to be successful if some of the contrast medium was placed within the joint. RESULTS: There were 78 male and 178 female patients, and the mean age was 54 years (range, 28 to 87 years). In 232 of the 256 patients (90.6%), the injection was deemed to have reached the glenohumeral joint, and these cases were considered successful. Among these patients, the contrast medium was shown only in the joint in 189 (73.8%), whereas in 43 (16.8%) it was shown both in and out of the joint. Of the 24 misguided injections, 15 (5.9%) had anterior placement, 6 (2.3%) had posterior placement, and 2 (0.8%) had superior placement, whereas the material was located in all portions outside the joint in 1 (0.4%). CONCLUSIONS: This study showed that our modified anterior approach had an accuracy greater than 90% for the intra-articular injection of the glenohumeral joint without radiographic guidance.

Gastric emptying time of oral contrast material in children and adolescents undergoing abdominal computed tomography.

OBJECTIVES: : Considering the hazards of pulmonary aspiration of oral contrast material (OCM) during general anesthesia, we investigated the gastric emptying time (GET) of OCM in children and adolescents undergoing abdominal computed tomography (CT). PATIENTS AND METHODS: : Included in the study were 101 consecutive patients ages 3.1 to 17.9 years (mean age 12.2 +/- 3.3 years), who underwent contrast-enhanced abdominal CT for suspected acute appendicitis (n = 90), abdominal trauma (n = 10), or suspected ileus (n = 1). Oral iodinated ioxithalamate was given for bowel opacification. Background data (age, sex, weight, chronic diseases, and medication intake), time of initiation and completion of OCM, and time of CT scanning were recorded. To estimate the GET of OCM, CT images were reviewed to examine whether the stomach was empty or full of OCM at the time of imaging. RESULTS: : The Kaplan-Meier curve showed that 75% of the patients had OCM in the stomach 48 +/- 5.2 minutes after its completion, 50% after 74 +/- 7.9 minutes, and 25% after 135 +/- 32.5 minutes; 1 patient still had OCM after 162 minutes. Except for the length of time taken to drink the contrast material (< or =90 minutes was associated with slower empting of the stomach; log rank, P = 0.03), GET of OCM was not correlated with sex (P = 0.16), age (P = 0.15), weight (P = 0.13), or type of diagnosis (P = 0.41). CONCLUSIONS: : Given the variability of GET of OCM and if clinically feasible, we advocate waiting at least 3 hours between completion of OCM ingestion and general anesthesia induction.

MDCT for suspected acute appendicitis in adults: impact of oral and IV contrast media at standard-dose and simulated low-dose techniques.

OBJECTIVE: The objective of this study was to prospectively investigate the influence of oral, IV, and oral and IV contrast media on the information provided by MDCT at standard and simulated low radiation doses in adults suspected of having acute appendicitis. SUBJECTS AND METHODS: One hundred thirty-one consecutive patients (80 women, 51 men; age range, 18-87 years; mean age, 37 years) suspected of having appendicitis were randomly assigned to either ingest or not ingest iodinated contrast material. Thereafter, all patients underwent IV unenhanced and enhanced abdominopelvic MDCT with a 4 x 2.5 mm collimation at 120 kVp and 100 mAs(eff). Dose reduction corresponding to 30 mAs(eff) was simulated. Two radiologists independently read scans during separate sessions, assessed appendix visualization, and proposed a diagnosis (i.e., appendicitis or an alternative diagnosis). The final diagnosis was based on either surgical findings or clinical follow-up. Data were analyzed by factorial analysis of multiple correspondences followed by an ascending hierarchic classification method. RESULTS: Factorial analysis and ascending hierarchic classification revealed that, in terms of diagnostic correctness, reader influence predominated over the influence of IV and oral contrast media use and radiation dose but that correctness was also influenced by the patient's sex (p = 0.048) and was lower in cases of alternative diseases (p < 0.001). Visualization of the appendix depended predominantly on the reader rather than on the use of IV, oral, or oral and IV contrast agents or on radiation dose. CONCLUSION: Diagnostic correctness is much more influenced by the reader than by the use of contrast medium (oral, IV, or both) or of simulated low-radiation-dose technique.

Does nasal irrigation enter paranasal sinuses in chronic rhinosinusitis?

BACKGROUND: Nasal irrigation is widely used in treating sinonasal diseases. Not only does it remove static secretions and promote mucociliary clearance, but, in chronic rhinosinusitis, nasal flush is also a potential route for topical drug administration into paranasal sinuses. A clinical study was conducted to investigate how well nasal irrigation could reach paranasal sinuses with the ostiomeatal units blocked in chronic rhinosinusitis. This study was performed to (1) assess the ability of a nasal douche and spray to deliver a solution into the paranasal sinuses in chronic rhinosinusitis and (2) compare the performance of the two techniques. METHODS: Fourteen patients, with bilateral chronic rhinosinusitis, underwent nasal irrigation with 140 mg/mL of iodinated contrast solution by 40 mL of douching using an irrigation syringe in one side, and 10 mL of spraying in the other side. A computed tomography scan was undertaken for each patient to determine the volume and the distribution of staining in the nose and paranasal sinuses. RESULTS: Only two patients had any staining, with a small amount present in a total of three maxillary sinuses (0.10 mL, 0.04 mL, and 0.13 mL). The mean volumes of paranasal sinus staining by nasal douche and nasal spray were 0.0093 and 0.01 mL, respectively. We found that the two techniques had a similar performance. Both of them delivered only a small amount of the solution, if any, into the sinuses (with a mean difference of -0.0007 mL; 95% CI, -0.02-0.02 mL; p = 0.94). CONCLUSION: Nasal douche and spray is not effective in delivering a nasal irrigation solution into paranasal sinuses in chronic rhinosinusitis.

Feasibility and impact of the measurement of extracellular fluid volume simultaneous with GFR by 125I-iothalamate.

The feasibility, validity, and possible applications of the assessment of extracellular fluid volume (ECFV) simultaneous with glomerular filtration rate (GFR) were assessed in a series of validation studies using the constant infusion method of (125)I-iothalamate (IOT). In 48 subjects with a broad range of GFR, distribution volume (V(d)) of IOT corresponded well with V(d) bromide (16.71 +/- 3.0 and 16.73 +/- 3.2 l, respectively, not significant), with a strong correlation (r = 0.933, P < 0.01) and without systematic deviations. Reproducibility assessment in 25 healthy male subjects showed coefficients of variation of 8.6% of duplicate measurement of V(d) IOT during strictly standardized (50 mmol Na(+)/d) sodium intake. An increase in dietary sodium intake (200 mmol Na(+)/d) induced a corresponding rise in V(d) IOT of 1.11 +/- 1.5 l (P < 0.01). In 158 healthy prospective kidney donors, the impact of indexing of GFR to ECFV was analyzed. Age, gender, height, and body surface area (BSA) were determinants of GFR. Whereas GFR, GFR/BSA, and GFR/height were gender-dependent, GFR/ECFV was gender-independent and not related to height or BSA. This supports the potential of normalizing GFR by ECFV. Thus, ECFV can be simultaneously assessed with GFR by the constant infusion method using IOT. After appropriate validation, also other GFR tracers could be used for such a simultaneous estimation, providing a valuable resource of data on ECFV in renal studies and, moreover, allowing GFR to be indexed to the body fluid compartment it clears: the ECFV.

Fluid-modulated bipolar radiofrequency ablation: an ex-vivo evaluation study.

BACKGROUND: The effect of radiofrequency ablation (RFA) can be modulated by fluid injection. PURPOSE: To evaluate the potential of different fluids to modulate the effect of bipolar RFA in an ex-vivo liver model. MATERIAL AND METHODS: A bipolar RFA system with an internally cooled needle-shaped applicator (20-mm active tip) was used to induce coagulation lesions in ex-vivo porcine liver. Prior to the ablation procedure, 1-ml samples of seven different fluids were injected (0.9% saline, gadopentetate dimeglumine, ioxithalamate, 10% hydroxyethyl starch, 5% glucose, 95% ethanol, distilled water). Each fluid was used for five RF ablations. During the procedure, applied energy, impedance, and time were recorded. Additionally, temperature was measured at a fixed distance of 0.5 and 1.0 cm from the RF probe. Generator output was set to 20 W, as recommended by the vendor. Five ablation procedures without fluid injection served as the reference standard. The lesion diameters were measured, and volume and an efficiency index (coagulation volume/procedure duration) calculated and compared (ANOVA, Student-Newman-Keuls test). RESULTS: In comparison to the reference standard, fluid injection resulted in an enlargement of mean coagulation volume for all fluids. In comparison to RF ablation alone (1.42+/-0.33 cm(3)), significant increase (P<0.001) of lesion size was found using gadopentetate dimeglumine, hydroxyethyl starch, glucose, and ethanol. The largest lesions were generated using preinjection of hydroxyethyl starch. Most energy could be applied after injection of glucose. Comparing the efficiency index, no statistically significant differences were found. CONCLUSION: Besides the modulation of the electrical conductivity, the increase in thermal conductivity also contributes to the enhancement of RFA by the injection of the tested fluids. Further studies are needed to evaluate this effect for larger injection volumes under in-vivo conditions.

[Renal radionuclide scintigraphy in the evaluation of radiopaque substances on renal function].

To evaluate the nephrotoxic effect of radiopaque substances (ROS) by renal radionuclide scintigraphy, 47 patients were examined before and after coronary ventriculography. Iohexol, iobitridole, and ioxythalamate were used as ROS in 15, 18, and 14 patients, respectively. The parameters of renal filtration and excretory function were calculated during study. Ioxythalamate was shown to have a less pronounced nephrotoxic effect.