Biomedical subjects

R Felix

Publications and source records attributed to R Felix.

At least 19 recordsLinked to original sources

PubMed2006

Pulmonary and caval blood flow patterns in patients with intracardiac and extracardiac Fontan: a magnetic resonance study.

AIMS: We compared in vivo blood flow and pulsatility after different types of Fontan operation using magnetic resonance imaging. MATERIAL AND METHODS: A total of 37 consecutive patients (mean age 19+/-7.9 years, 7.3+/-3.2 years after Fontan operation), 7 with atriopulmonary anastomosis (APC), 18 with intra-atrial lateral tunnel (LTFO) and 12 with extracardiac Fontan (ECFO) were studied using magnetic resonance phase-contrast velocity mapping. Blood flow (volume flow) in the superior vena cava (SVC), inferior vena cava (IVC) and both pulmonary arteries were measured and a pulsatility index was calculated for each vessel. RESULTS: For all modifications, the blood flow distribution between the SVC and IVC was normal (1:2). Patients with APC had a normal pulsatility, a dilated right atrium, partial backward flow in the IVC and physiological blood flow distribution between the pulmonary arteries. LTFO and ECFO patients had no retrograde flow in the IVC, equal blood flow distribution between the pulmonary arteries and very low or absent pulsatility. CONCLUSIONS: MRI allows hemodynamic quantification and characterization of various types of Fontan modifications and may be a valuable tool to predict Fontan failure. Despite showing normal pulsatility, patients with APC have right atrial dilatation and partial backward flow in the IVC, demonstrating suboptimal Fontan circulation. LTFO and ECFO both produce unidirectional antegrade flow in the IVC but pulsatility is very low or absent, which may promote poor pulmonary artery growth and increase of pulmonary vascular resistance contributing to late Fontan failure.

Adolescent↗

PubMed2006

123I-IMT SPECT for evaluation of the response to radiation therapy in high grade gliomas: a feasibility study.

Assessing response to radiation therapy in patients with high grade gliomas is needed upon making decisions toward further therapy strategies. Currently used standard imaging tools such as CT and MRI are not sensitive enough to detect early therapy effects. We prospectively investigated if single photon emission computed tomography (SPECT) using radiolabelled amino acid derivate (123)I-methyltyrosine (IMT) would be useful for this aim. 10 patients with histologically proven high grade gliomas, who were candidates for radiation therapy, were enrolled in this investigation. All patients were examined by IMT SPECT before radiation therapy and 4 weeks after the initiation of the hypofractionated application of 40 Gy. Patients were followed up for 39 months; the tumours to background ratios (T/B) for IMT under/before radiation therapy were correlated to survival times. Initially, SPECT depicted an abnormal intratumoural IMT uptake in all patients (mean T/B ratios 1.37-1.87). In four out of 10 patients, the mean T/B ratios decreased by more than 10% under radiation therapy. In six other patients, the BQ decreased by less than 10% or increased. There were no significant correlations between the degree of changes in T/B and survival (r = -0.1, p = 0.973). Serial IMT SPECT measurements allow detection of changes in amino acid accumulation in high-grade gliomas under radiation therapy. However, these changes seem to possess no prognostic value in respect to survival prediction.

Adult↗

PubMed2006

Impact of FDG-PET/MRI image fusion on the detection of pancreatic cancer.

BACKGROUND: This study assessed the value of image fusion with (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) in patients suspected of having pancreatic cancer. METHODS: 32 patients (12 women, 20 men; age 24-79 years; mean 56.6 years) were included. All patients underwent whole-body FDG-PET examinations and contrast-enhanced MRI. Image fusion used a semiautomatic voxel-based algorithm. Separate reading, side-by-side analysis and evaluation of fused PET/MRI images were performed. Results were correlated to histopathology (n = 30), or clinical follow-up (n = 2). RESULTS: 15/32 patients had pancreas cancer and 17/32 patients benign disease. The sensitivity and specificity for cancer detection by FDG-PET were 93 and 41% for visual and 86 and 58% for semiquantitative analysis whereas MRI achieved 100 and 76% respectively. Topographical assignment of PET foci by image fusion was superior to side-by-side analysis in 11/39 (28%) foci (in 8/32 patients). However, a true impact on therapeutic strategy was observed only in 1/8 patients as the presence of multiple metastases, irresectable primaries or medical reasons for inoperability prevented a curative setting. CONCLUSION: Compared to side-by-side analysis, PET/MRI image fusion improves the anatomical assignment and interpretation of FDG foci. The therapeutic benefit for the patient however is limited in patients with multiple lesions or incurable primaries.

Adenocarcinoma↗

PubMed2006

Pulmonary regurgitation is a powerful factor influencing QRS duration in patients after surgical repair of tetralogy of Fallot. A magnetic resonance imaging (MRI) study.

AIMS: QRS prolongation is a negative prognostic factor for the development of ventricular arrhythmia after repair of tetralogy of Fallot (TOF). In this MRI study, we performed a multivariate analysis to determine the influence of volumetric and functional parameters as well as time factors on QRS duration. METHODS AND RESULTS: Sixty-seven patients after surgical repair of TOF were studied using a 1.5T MRI. Measurement of the ventricles was performed with a multislice-multiphase sequence. Left and right ventricular volumes, ejection fractions (EF) and myocardial masses were determined. Pulmonary regurgitant fraction (PRF) was quantified by velocity encoded flow measurement in the main pulmonary artery. Maximum QRS duration was taken from a 12-channel ECG. Mean maximum QRS duration was 132 ms (+/- 29 ms). Mean PRF was 29.2% (+/- 13.4%). QRS duration correlated significantly with PRF (r = 0.49; p < 0.01; n = 54) and with right ventricular enddiastolic volume index (RVEDVI) (r = 0.29; p < 0.05; n = 67). Multivariate analysis revealed that the combination of PRF, postoperative period, age at surgical repair, and left ventricular (LV) enddiastolic volume are correlated with QRS prolongation. CONCLUSION: In patients after repair of TOF, pulmonary regurgitation is related to QRS prolongation. Furthermore, even LV size plays a role in the enlargement of the QRS complex.

Adolescent↗

PubMed2006

Corrections of arterial input function for dynamic H215O PET to assess perfusion of pelvic tumours: arterial blood sampling versus image extraction.

Assessment of perfusion with 15O-labelled water (H215O) requires measurement of the arterial input function (AIF). The arterial time activity curve (TAC) measured using the peripheral sampling scheme requires corrections for delay and dispersion. In this study, parametrizations with and without arterial spillover correction for fitting of the tissue curve are evaluated. Additionally, a completely noninvasive method for generation of the AIF from a dynamic positron emission tomography (PET) acquisition is applied to assess perfusion of pelvic tumours. This method uses a volume of interest (VOI) to extract the TAC from the femoral artery. The VOI TAC is corrected for spillover using a separate tissue TAC and for recovery by determining the recovery coefficient on a coregistered CT data set. The techniques were applied in five patients with pelvic tumours who underwent a total of 11 examinations. Delay and dispersion correction of the blood TAC without arterial spillover correction yielded in seven examinations solutions inconsistent with physiology. Correction of arterial spillover increased the fitting accuracy and yielded consistent results in all patients. Generation of an AIF from PET image data was investigated as an alternative to arterial blood sampling and was shown to have an intrinsic potential to determine the AIF noninvasively and reproducibly. The AIF extracted from a VOI in a dynamic PET scan was similar in shape to the blood AIF but yielded significantly higher tissue perfusion values (mean of 104.0 +/- 52.0%) and lower partition coefficients (-31.6 +/- 24.2%). The perfusion values and partition coefficients determined with the VOI technique have to be corrected in order to compare the results with those of studies using a blood AIF.

Femoral Artery↗

PubMed2006

Real time 3D (4D) ultrasound-guided percutaneous biopsy of solid tumours.

PURPOSE: The aim of the current study was to investigate the feasibility of real-time 3D (4D) ultrasound-guided biopsy. MATERIALS AND METHODS: Between 2003 and 2005, 53 patients with suspicious lymph nodes or solid tumours underwent 4D ultrasound-guided core needle biopsy using a 4D US-System (Voluson 730, GE/Kretztechnik, Austria). The results were documented prospectively and compared to a matched series of 53 conventional 2D ultrasound-guided core biopsies. RESULTS: 4D ultrasound-guided biopsy can be performed using multiplanar views or a combination of cross-sectional and rendered images. Assessment of additional 3D images during the biopsy procedure was helpful in 34 % of the cases. In the differentiation of malignant and benign lesions, 4D ultrasound guided biopsy yielded 35 true-positive results, 12 true-negative results and 5 false-negative results. The sensitivity and specificity for the diagnosis of malignancy was 87.5 % and 94.4 %, respectively (control group: 89.5 % and 94.4 %). There was one case of insufficient tissue sampling in the 4D targeting group and 2 cases in the control group. No complications were observed related to the biopsy procedure. CONCLUSIONS: 4D ultrasound-guided biopsy is feasible and can improve visualisation of biopsy procedures by multiplanar display or 3D rendering. Although the accuracy is comparable to that of conventional 2D biopsy, this technique may be helpful for biopsy of lesions with close relation to relevant anatomical structures.

Adult↗

PubMed2006

Magnetic resonance imaging of orbital tumors.

This contribution provides an overview of diseases of eye and orbit and their appearance on magnetic resonance imaging. In recent years the diagnosis of eye and orbit pathology has profited significantly from increasingly sophisticated technical developments in the field of tomographic methods. Due to the small size of the examination area the improvement in spatial resolution and soft tissue contrast leads to an increase in image quality. In most clinical questions concerning eye and orbit pathologies magnetic resonance imaging is superior to computed tomography and should be early performed.

Contrast Media↗

PubMed2006

Imaging of serotonin transporters and its blockade by citalopram in patients with major depression using a novel SPECT ligand [123I]-ADAM.

We studied the midbrain SERT availability in patients with major depression and assessed the relation of SERT occupancy by citalopram to the treatment response. 21 non-medicated patients with major depression and 13 healthy controls were examined by [(123)I]-ADAM SPECT. The midbrain SERT availability (SERT V(3)'') was calculated using individual MRI scans. In 13/21 patients SPECT was repeated 7 days after oral medication with citalopram (10 mg/day). We found no significant difference in the mean midbrain SERT availability between the studied patients with major depression and healthy controls (0.86 +/- 0.27 vs. 0.71 +/- 0.44, p = 0.069). The mean SERT occupancy accounted to 61%. The degree of SERT blockade by citalopram did not correlate with the reduction in HAMD total score. Treatment with low-dosed citalopram caused individually variable occupancy of the midbrain-SERT and a rapid clinical improvement in 54% of the investigated patients.

Adult↗

PubMed2006

[Radiation dose of the radiologist and the assistant in transarterial hepatic chemoembolization--comparison with the dose limits].

PURPOSE: To determine the values of effective dose and partial body dose for the radiologist and the assistant during transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) und to compare the doses with the dose limits. MATERIALS AND METHODS: In 65 TACE of HCC cases, values of various surface doses for the radiologist and the assistant were measured. The measurements were performed with the help of thermoluminescence dosemeters (TLD) that were attached to the eyebrows, over the lobes of the thyroid gland, to the breasts, abdomen and symphysis, and to the hands and the lower legs. The measured surface dose values were used as indicators of the exposure of the organs and tissues located near the surface, i. e. eye lens, thyroid gland, breast, testes and tibia. They were also seen as conservative estimations of tissues deep inside the body and the extremities. RESULTS: The highest surface dose for the radiologist was measured at the lower leg (0.58 +/- 0.28 mSv) and the highest surface dose for the assistant was measured at the right lower leg (0.24 +/- 0.20 mSv) since it was closer to the tube than the left side, followed by the dose values at the also unprotected areas of the eyebrows, lobes of the thyroid gland and the hands. The estimated value of the effective dose was 0.06 +/- 0.03 mSv for the radiologist and 0.04 +/- 0.01 mSv for the assistant. With regard to the relationship between the dose limits according to the German X-ray regulation and the measured values and with regard to the maximum possible number of interventions per year, the partial body dose of the red bone marrow in the lower leg provided the greatest limitation, followed by the partial body dose of the muscle in the lower leg and the effective dose. CONCLUSION: In order to meet the dose limits, especially the lower leg should be protected, and the effective dose should also be reduced.

Allied Health Occupations↗

PubMed2006

Influence of neoadjuvant radiochemotherapy combined with hyperthermia on the quality of life in rectum cancer patients.

PURPOSE: The present study compares quality of life (QoL) after neoadjuvant radiochemotherapy with or without hyperthermia in patients with advanced rectal cancer. METHODS: Between April 1994 and May 1999, 137 patients were treated by neoadjuvant radiochemotherapy with (69 patients (50.4%)) or without (68 patients (49.6%)) hyperthermia. Forty-six patients (33.6%) filled-out a 'Gastrointestinal Quality of Life Index' (GIQLI) questionnaire at four time points (before and after neoadjuvant therapy, early after surgery and after long-term follow-up) and were included in the present study. RESULTS: There were no statistically significant differences in the global GIQLI index between patients treated with neoadjuvant radiochemotherapy with and without hyperthermia at any time point. The longitudinal analysis of GIQLI values in both treatment groups showed specific profiles that were identical in both treatment groups. Occurrence of severe toxicity during the neoadjuvant therapy in both arms lead to a significant temporary reduction of QoL scores at TP2 without any detrimental long-term effects. Patients with sphincter preservation and patients with sphincter resection reported similar QoL scores during long-term follow-up. CONCLUSION: Neoadjuvant radiochemotherapy with and without hyperthermia has similar effects on the QoL of patients with locally advanced rectal cancer. The addition of hyperthermia during the neoadjuvant therapy with the potentially associated inconveniences has no negative effects on QoL.

Adult↗

PubMed2006

Magnetic resonance imaging in the assessment of cystic pancreatic lesions: differentiation of benign and malignant lesion status.

PURPOSE: To characterize cystic pancreatic lesions and tumors with magnetic resonance imaging (MRI), and to assess the value of morphological criteria in differentiating pseudocysts versus cystic tumors and benign versus malignant cystic tumors. MATERIAL AND METHODS: Twenty-three patients with cystic pancreatic tumors or lesions underwent plain and contrast-material-enhanced MRI, including magnetic resonance cholangiopancreatography (MRCP). The MR findings were characterized and analyzed by two readers, and the role of various imaging criteria and combinations thereof for final lesion assignment were assessed. Final diagnoses were obtained from the results of open surgery (n = 19) and/or biopsy (n = 4). RESULTS: Final diagnoses included cystic tumors (n = 11) and pseudocysts (n = 12). The lesions were located in the head (56%) and body or tail (44%). Lesion diameters ranged from 7 to 50 mm. Various lesion contrast enhancement patterns were observed for both benign and malignant lesions. Serous cystadenomas were located in the head, they were lobulated, and had wall diameters < or = 2 mm; with the combination of these characteristics all patients with serous cystadenoma could be identified, whereas in no other patient was this constellation observed. CONCLUSION: MRI facilitated the diagnosis of serous cystadenomas, although no definite morphologic criterion for the differentiation between pseudocysts and mucinous cystadenomas was identified. In consideration of the substantial therapeutic consequences, either diagnostics in unclear cystic pancreatic lesions should comprise cyst fluid analysis if necessary, or eligible patients should be referred for surgical resection.

Adult↗

PubMed2006

Hepatocellular carcinoma in association with hepatic focal nodular hyperplasia.

PURPOSE: To report the association between hepatocellular carcinoma (HCC) and hepatic focal nodular hyperplasia (FNH) and the possible impact on clinical decision-making with regard to resective approaches in patients with FNH. MATERIAL AND METHODS: We retrospectively analyzed the findings in 77 adult patients who underwent liver resections for FNH between October 1989 and September 2001 at our center. HCC within the confines of FNH was found in two patients. We demonstrate the magnetic resonance imaging (MRI) and macroscopic and microscopic findings. RESULTS: Presurgical MRI demonstrated heterogeneous signal characteristics of moderately hyperintense FNH on T2-weighted images and, after i.v. administration of superparamagnetic iron oxide particles, HCC in FNH was barely delineable. Both patients underwent successful right hemihepatectomy to remove the suspicious FNH with diameters of 12 and 14 cm; intralesional HCC diameters were 3 and 5 cm, respectively. Patients could be rapidly dismissed. However, one patient died after recurrence of HCC 1.5 years after surgery, whereas the other patient continues tumor-free 4 years after surgery. Alpha-feto-protein was normal in both patients. CONCLUSION: In FNH with rapid growth tendency and heterogenic MR appearance, surgical removal should be considered to overcome the risk of inadequate therapy in the very rare group of patients with HCC in association with FNH.

Carcinoma, Hepatocellular↗

PubMed2006

Magnetic resonance-guided biopsy of suspicious breast lesions with a handheld vacuum biopsy device.

PURPOSE: To evaluate a handheld vacuum-assisted device system for magnetic resonance image (MRI)-guided breast lesion biopsy. MATERIAL AND METHODS: In 32 patients, a total of 42 suspicious breast lesions (mean diameter 7.5 mm for mass lesions, 11.6 mm for non-masslike diffuse lesions) seen with MRI (no suspicious changes in breast ultrasound or mammography) were biopsied (27 lateral, 15 medial) using a 10G vacuum-assisted breast biopsy device under MR guidance. Histology of biopsy specimens was compared with final histology after surgery or follow-up in benign lesions. RESULTS: In all biopsies, technical success was achieved. Histology revealed 11 lesions with ductal carcinoma in situ (DCIS) or invasive cancer, three with intermediate lesions (LCIS) and 28 with benign breast lesions (adenosis, infected hematoma). In one patient with discordant results of MRI and histology, surgical excision revealed medullary cancer. In the follow-up (mean 18 months) of the histological benign lesions, no breast cancer development was observed. Besides minor complications (hematoma, n = 6), with no further therapeutic interventions, no complications occurred. CONCLUSION: MRI-guided breast lesion biopsy using a handheld vacuum-assisted device is a safe and effective method for the work-up of suspicious lesions seen with breast MRI without changes in mammography or ultrasound. In the case of discordant histology of vacuum biopsy and breast MRI appearance, surgical excision is recommended.

Adult↗

PubMed2006

Comparison of MR-thermography and planning calculations in phantoms.

A systematic comparison of three-dimensional MR (magnetic resonance) thermography and planning calculations in phantoms for the hyperthermia (HT) SIGMA-Eye applicator. We performed 2 x 6 experiments in a homogeneous cylindrical and a heterogeneous elliptical phantom by adjusting 82 different patterns with different phase control inside an MR tomograph (Siemens Magnetom Symphony, 1.5 Tesla). For MR thermography, we employed the proton resonance frequency shift method with a drift correction based on silicon tubes. For the planning calculations, we used the finite-difference time-domain (FDTD) method and, in addition, modeled the antennas and the transforming network. We generated regions according to a segmentation of bones and tissue, and used an interpolation technique with a subgrid of 0.5 cm size at the interfaces. A Gauss-Newton solver has been developed to adapt phases and amplitudes. A qualitative agreement between the planning program and measurements was obtained, including a correct prediction of hot spot locations. The final deviation between planning and measurement is in the range of 2-3 W/kg, i.e., below 10%. Additional HT phase and amplitude adaptation, as well as position correction of the phantom in the SIGMA-Eye, further improve the results. HT phase corrections in the range of 30-40 degrees and HT amplitude corrections of +/- 20-30% are required for the best agreement. The deviation /MR-FDTD/, and the HT phase/amplitude corrections depend on the type of phantom, certain channel groups, pattern steering, and the positioning error. Appropriate agreement between three-dimensional specific absorption rate distributions measured by MR-thermography and planning calculations is achieved, if the correct position and adapted feed point parameters are considered. As long as feed-point parameters are uncertain (i.e., cannot be directly measured during therapy), a prospective planning will remain difficult. However, we can use the information of MR thermography to better predict the patterns in the future even without the knowledge of feed-point parameters.

Algorithms↗

PubMed2006

Radiation risks for the radiologist performing transjugular intrahepatic portosystemic shunt (TIPS).

The aim of this study is to evaluate the radiation dose to the interventional radiologist in transjugular intrahepatic portosystemic shunt (TIPS) concerning the risk of cancer and deterministic radiation effects and the relation to recommended dose limits. In 18 TIPS interventions radiation doses were measured with thermoluminescence dosemeters (TLD) fixed at the eyebrow, thyroid and hand of the radiologist without special lead shielding of these body parts and at the chest, abdomen and testes under the lead apron. The doses of the eye lens, thyroid gland and hand were assumed to be equal to the corresponding surface doses. The dose at the abdomen under the lead apron was used as an estimation of the ovarian dose. Effective dose equivalent was estimated by Webster's method. The estimated effective dose equivalent was 0.087 mSv and the effective dose 0.110 mSv. The risk of fatal cancer was of 10(-6) and the risk of severe genetic defect of 10(-7) for one single intervention. The maximum permissible number of TIPS interventions was 181, otherwise the dose limit for effective dose would be exceeded. When the radiologist performed more than 372 TIPS procedures per year for many years, the dose to the lens of the eye could exceed the threshold for cataract. If the interventionist performs a large number of TIPS procedures in a year, the risk of fatal cancer and developing cataracts becomes relatively high.

Female↗

PubMed2006

[Determination of ventricular volumes in coronary artery disease: comparison of two gated SPECT analysis tools with MRI].

AIM: Comparison of two gated SPECT analysis tools -- gated SPECT quantification (GSQ) and emory cardiac toolbox (ECT) -- in patients with coronary artery disease (CAD) and severely impaired left ventricular function (preoperative: EF <35% by cardiac catheter). PATIENTS, METHODS: A total of 56 gated SPECT examinations (one-day hybrid-protocol with (201)Tl-chloride for rest and (99m)Tc-sestamibi for stress applied during low-dose dobutamine stress MR-examination; temporal resolution; 8 phases per cardiac cycle) were performed in 36 patients (31 preoperatively, 25 postoperatively) and compared with MRI in 48 cases. Left ventricular end-diastolic (LV-EDV) and end-systolic (LV-ESV) volumes as well as the left ventricular ejection fraction (LV-EF) were calculated. RESULTS: The total volumetric assessment by both analysis algorithms (n = 56) showed good intraclass correlation coefficients preoperatively (n = 31), but even better postoperatively (n = 25). The mean reconstruction time was approximately 3 minutes ( +/- 2 SD) for GSQ and 15 minutes ( +/- 5 SD) for ECT. In comparison to MRI the results of both analysis tools also correlated well, but the agreement decreased in the presence of scared tissue. The mean LV-EF (MRI) preoperatively was 30.4%, in 6/36 patients above the values calculated from cardiac catheter, postoperatively 34.6%. CONCLUSION: Both gated SPECT analysis tools showed reliable volumetric assessments in high-risk patients with CAD and severely reduced LV-EF in comparison to MRI, with advantages for GSQ in terms of postprocessing time. However, for the calculation of LV-EF a markedly lower concordance with MR-results was observed for both methods depending on the presence of myocardial scars.

Aged↗

PubMed2006

Embolization of experimental wide-necked aneurysms with iodine-containing polyvinyl alcohol solubilized in a low-angiotoxicity solvent.

BACKGROUND AND PURPOSE: To evaluate the ready-to-use iodine-containing polyvinyl alcohol (I-PVA) dissolved in the low angiotoxic solvent N-methyl pyrrolidone (NMP) for embolization of porcine wide-necked aneurysms. METHODS: Fourteen broad-based carotid sidewall aneurysms were surgically constructed in 7 swine. I-PVA (40%) in NMP was injected under temporary balloon occlusion bridging the aneurysm neck. After 4 weeks, follow-up angiography, multisection CT angiography (MSCTA), and 3T MR imaging including MR angiography (MRA) sequences were performed. Afterward, harvested aneurysms were investigated histopathologically. RESULTS: The liquid embolic was well visible under fluoroscopy and displayed a favorable precipitation pattern, allowing for controlled polymer delivery. Ten aneurysms (71%) were initially completely occluded, whereas in 1 aneurysm, a minimal polymer leakage was observed. The other 4 aneurysms (29%) were almost completely occluded. One animal suffered a lethal rebleeding from the anastomosis after uneventful embolization. Aneurysms embolized with I-PVA could be discriminated well from the parent artery without beam-hardening artifacts on MSCTA, and no susceptibility artifacts were encountered on MR imaging. Histologic examination revealed all aneurysms covered with a membrane of fibroblasts and an endothelial cell layer while a moderate intraaneurysmal inflammatory response to the polymer was observed. CONCLUSION: I-PVA dissolved in NMP has proved its effectiveness for the embolization of experimental wide-necked aneurysms. This precipitating liquid embolic offers several interesting features in that it needs no preparation before use and no radiopaque admixtures, the latter allowing for artifact-free evaluation of treated aneurysms with MSCTA and MRA. Moreover, it uses NMP as a solvent, which has only a low angiotoxicity.

Animals↗

PubMed2006

Organic solvents as vehicles for precipitating liquid embolics: a comparative angiotoxicity study with superselective injections of swine rete mirabile.

BACKGROUND AND PURPOSE: The organic solvent dimethyl-sulfoxide (DMSO), as a commonly used vehicle for nonadhesive liquid embolics, is not devoid of local angiotoxic effects. We compared microvascular toxicities of superselective infusions of DMSO with potentially more compatible solvents in swine rete mirabile. METHODS: Fourteen swine underwent angiography for superselective catheterization of 28 arteries of the rete while electrocardiography and intra-arterial pressure were continuously monitored. The investigated solvents were DMSO, dimethyl isosorbide (DMI), ethyl lactate, glycofurol 75, N-methyl pyrrolidone (NMP), and solketal. Control infusion of saline ruled out catheter induced vasospasm in all cases. Each artery of the rete was infused only once with 0.8 mL of one of the solvents over 60 seconds. Acute angiographic and hemodynamic consequences were evaluated. Blood samples were assessed for signs of intravascular hemolysis. Brains and retia were harvested for gross and histopathologic investigation. RESULTS: On the basis of the angiographic data, DMSO induced the most pronounced vasospasm with the longest recovery period of all solvents investigated. Ethyl lactate, glycofurol 75, and solketal elicited less severe vasospasms and accordingly resolved much more quickly. DMI and NMP induced only minimal vasospasms with comparably short duration. No solvent caused significant hemodynamic alterations or hemolysis. Gross inspection of brains showed no abnormalities, whereas histopathologic examination revealed mostly nonspecific findings. One rete exposed to solketal displayed possible causal histotoxic changes. CONCLUSION: DMI and NMP produced far less vasospasm than DMSO. No changes in hemodynamic or hemolytic parameters and no histopathologic findings were observed with infusion of these solvents.

Alkenes↗