[Application of C-arm computed tomography in cardiology]. / Kardiale Anwendung der C-Arm-Computertomographie.

C-arm computed tomography is currently being introduced into cardiac imaging and offers the potential for three-dimensional imaging of the cardiac anatomy within the interventional environment. This detailed view is necessary to support complex interventional strategies, such as transcutaneous valve replacement, interventional therapy of atrial fibrillation, implantation of biventricular pacemakers and assessment of myocardial perfusion. Currently, the major limitation of this technology is its insufficient temporal resolution which limits the visualization of fast moving parts of the heart.

[C-arm CT for chemo-embolization of liver tumors]. / C-Arm-CT bei der Chemoembolisation von Lebertumoren.

Local efficacy of transarterial chemo-embolization (TACE) is enhanced if selective treatment is performed. Selectivity of TACE mainly depends on vascular anatomy but also on the identification and catheterization of tumor feeding arteries. Correlation of vascular territories and target tumor volume in angiographic projection images is more difficult if tumors are not hypervascularized and contrast of liver parenchyma is inhomogeneous.C-arm CT offers the option of selective perfusion imaging via tumor-feeding arteries. This allows the comparison of perfusion images and baseline cross-sectional imaging to evaluate if tumors are covered completely by local treatment and to change the catheter position if necessary. Furthermore the uptake of embolization material, such as lipiodol can be checked by C-arm CT.In a prospective study of 75 TACE of liver tumors and liver metastases we evaluated the appropriateness of 85 catheter positions ready for delivery by perfusion C-arm CT and compared the diagnostic confidence of angiography and perfusion C-arm CT in terms of judgment of correct catheter position for the planned treatment. Diagnostic confidence was improved by perfusion C-arm CT in 55% of cases and in 11 cases (13%) catheter positions were inappropriate and had to be corrected. The reasons for catheter repositioning were incomplete coverage of the target tumor by perfusion volume (mismatch) in 6 cases, inappropriate perfusion of adjacent liver parenchyma in 2 cases and non-selective tumor perfusion via collateral arteries in 3 cases. C-arm CT allowed sufficient visualization of uptake of lipiodol in all cases evaluated.The diagnostic benefit of C-arm CT increases if tumors are treated more selectively, are not strongly hypervascular, are located centrally and if the enhancement of liver parenchyma is inhomogeneous. C-arm CT causes additional working time and contrast load, which is relatively low compared to angiography. Radiation exposure of 151 microGy per C-arm series necessitates careful and therapy-oriented assessment of indications.

[C-arm CT for planning and guidance of extrahepatic embolizations]. / C-Arm-CT zur Planung und Steuerung extrahepatischer Embolisationen.

Interventional radiological vascular embolizations are complex procedures that require exact imaging of the target region to facilitate safe and effective treatment. The purpose of this paper is to present the technique and feasibility of flat detector C-arm computed tomography (C-arm CT) for control and guidance of extrahepatic abdominal embolization procedures. C-arm CT images can provide important information on both vascular and cross-sectional anatomy of the target region, help in determining therapy endpoints and provide follow-up during and immediately after the abdominal interventions.The cases presented demonstrate that C-arm CT images are beneficial for abdominal embolization procedures and facilitate precise treatment.

[C-arm CT-guided 3D navigation of percutaneous interventions]. / C-Bogen-CT-unterstützte 3D-Navigation perkutaner Interventionen.

So far C-arm CT images were predominantly used for a precise guidance of an endovascular or intra-arterial therapy. A novel combined 3D-navigation C-arm system now also allows cross-sectional and fluoroscopy controlled interventions. Studies have reported about successful CT-image guided navigation with C-arm systems in vertebroplasty. Insertion of the radiofrequency ablation probe is also conceivable for lung and liver tumors that had been labelled with lipiodol. In the future C-arm CT based navigation systems will probably allow simplified and safer complex interventions and simultaneously reduce radiation exposure.

Catheter-based intraluminal optical coherence tomography versus endoluminal ultrasonography of porcine ureter ex vivo.

OBJECTIVES: To compare the distinction of tissue layers of porcine ureters ex vivo between optical coherence tomography (OCT) and endoluminal ultrasonography (ELUS). Catheter-guided OCT is a new method of intraluminal microstructural imaging, with a spatial resolution of 10-20 mum. METHODS: Porcine ureters and kidneys were obtained fresh from the municipal slaughtery, cannulated with a 7F catheter sheath, flushed with normal saline solution, and marked on the outside with surgical suture. Between the marked positions, images were obtained from within the ureter lumen using OCT (M1, Lightlab, Westport, MA) and ELUS at 40 MHz. The distinction of the urothelium, lamina propria, and inner and outer muscle layers was rated as possible (1) or impossible (0) by 2 independent observers (O1, O2). The rates of distinction were compared between OCT and ELUS image quadrants using the chi(2) test. RESULTS: Of the 224 OCT image quadrants and 144 ELUS image quadrants, OCT was superior to ELUS in the distinction of any wall layers (O1, chi(2)P = 68.1051, P < .001; O2, chi(2)P = 66.1630, P < .001), urothelium and lamina propria (O1, chi(2)P = 200.0750, P < .001; O2, chi(2)P = 240.0024, P < .001), and lamina propria and muscle layer (O1, chi(2)P = 38.8411, P < .001; O2, chi(2)P = 24.7536, P < .001) but was inconclusive for the inner and outer muscle layer (O1, chi(2)P = 260.3004, P < .001; O2, chi(2)P = 0.4992, P > .25). CONCLUSIONS: OCT was able to distinguish significantly better than ELUS between different wall layers of porcine ureter ex vivo. The feasibility of OCT in vivo and in the presence of pathologic wall thickening of the ureter remains to be demonstrated.

Investigation on radiofrequency and laser (980 nm) effects after endoluminal treatment of saphenous vein insufficiency in an ex-vivo model.

OBJECTIVES: An ex-vivo model for the experimental evaluation of endoluminal thermal procedures for occlusion of saphenous veins was developed. Radiofrequency obliteration (RFO) and endovenous laser therapy (ELT) were compared using this model. DESIGN: Experimental ex-vivo treatment study. MATERIALS AND METHODS: The model consists of the subcutaneous foot veins from freshly slaughtered cows which were reperfused in situ with heparinised bovine blood. The veins were treated with either radiofrequency (RFO n=5) or with endoluminal 980 nm laser light (ELT n=5) using a continuous pull-back for RFO and a stepwise illumination and pull-back protocol for ELT. Immediately after treatment perivenous tissue and veins were examined macroscopically. In a second study the same treatment parameters were used in four further vein segments with RFO (n=2) and ELT (n=2). These vein segments were examined microscopically in HE-stained histological sections. RESULTS: Induration of the vessel wall and contraction of the vessel lumen were observed after RFO. Laser treatment produced carbonised lesions of the vein wall. After 12-24 laser exposures these lesions often became transmural, causing complete perforation of the vessel wall. Histological evaluation after radiofrequency treatment demonstrated homogenous circular thermal tissue alteration with disintegration of intima and media structures. Histological evaluation after endovenous laser treatment showed large variations of thermal tissue effects. Tissue effects ranged from major tissue ablation and vessel wall disruption to minor effects located between laser exposures and on the opposite vessel wall. CONCLUSIONS: Our model is suitable for systematic scientific evaluation of endovenous thermal occlusion procedures. Our first results and theoretical considerations indicate that endovenous laser treatment should be modified in order to ensure controlled homogenous circular thermal damage, avoiding vessel wall perforation and damage to perivascular structures.

[Intravascular optical coherence tomography: differentiation of atherosclerotic plaques and quantification of vessel dimensions in crural arterial specimens]. / Intravaskuläre optische Kohärenztomographie: Unterscheidung verschiedener Plaquetypen und Vermessung von Gefässdimensionen in atherosklerotischen Unterschenkelarterien.

PURPOSE: Intravascular optical coherence tomography (OCT) is a new technique based on infrared light that visualizes the arteries with a resolution of 10-20 microm. Intravascular ultrasound (IVUS) is the current in vivo reference standard and provides a resolution of 100-150 microm. This study compared OCT to IVUS and histopathology with respect to the ability to differentiate atherosclerotic plaques and quantify vascular dimensions in peripheral crural arteries ex vivo. MATERIALS AND METHODS: 50 segments of atherosclerotic arteries derived from five amputated human lower extremities were examined. The different plaque types (fibrous, high-lipid content, calcified) were assigned by two independent examiners, and the sensitivity and specificity of OCT in comparison with histopathology as well as intra- and interobserver consensus were calculated. A comparison of OCT with IVUS addressed the parameters: luminal area (LA), vascular wall area (VA) and plaque area (PA). RESULTS: When comparing OCT and histopathology with respect to the differentiation of various plaque types, sensitivities of 81 % and specificities of 89 % for fibrous plaques, of 100 % and 93 % for lipid-rich plaques and of 80 % and 89 % for calcified plaques were achieved (overall correlation 83 %). Intra- and interobserver consensus was very high (kappa = 0.86 and kappa = 0.89, p < 0.001, respectively). There was also a high correlation between quantitative measurements (Bland-Altman plot [LA]: mean bias, 0.1 mm(2) accuracy +/- 1.8 mm(2), r = 0.95 [p < 0.001] Bland-Altman plot [VA]: mean bias, 0.3 mm(2) accuracy +/- 2.3 mm(2), r = 0.94 [p < 0.001] Bland-Altman plot [PA]: mean bias, 0.4 mm(2) accuracy +/- 2.3 mm(2), r = 0.80 [p < 0.01]. CONCLUSION: OCT allows the differentiation of atherosclerotic plaque types in crural arteries with high accuracy compared to histopathology. Quantitative measurements show a high correlation with IVUS, the current reference standard.

Acute limb ischemia after femoral arterial closure with a vascular sealing device: successful endovascular treatment.

We report on successful catheter therapy of acute occlusions of popliteal and crural arteries due to distal embolization from a vascular sealing device. A 45 years-old male patient underwent percutaneous coronary angiography. After primary successful closure of the right femoral artery by a sealing device the patient developed acute ipsilateral lower limb ischemia, most probably due to embolization of a collagen/thrombin plug. Occlusions of the popliteal and crural vessels were successfully treated by percutaneous thrombectomy, thrombolysis and ballon angioplasty. Combined percutaneous catheter therapy is a therapeutic option for occlusions of popliteal and crural vessels due to embolization from a vascular sealing device.

[Value of MR angiography in follow-up after cruro-pedal bypass surgery]. / Wertigkeit der MR-Angiographie im follow-up nach cruro-pedalen Bypassanlagen.

Patients after crural or pedal revascularization need a consequent surveillance to prevent graft failure. We compared the results of the clinical examination including duplexscanning with contrast-enhanced magnetic resonance angiography (MRA). 26 bypass grafts were evaluated for potential stenosis in five locations. Using both techniques, 93 of 109 locations were classified identically. 10 of 16 locations which were categorized differently were reviewed angiographically (DSA). In contrast to duplexscanning, MRA detected 3 high grade stenosis, which had to be dilatated percutaneously. MRA should be used regularly in surveillance programs of distal bypass grafting.

A severe case of pneumatosis cystoides intestinalis with massive accumulation of gas outside the gastrointestinum.

We report an unusually severe case of pneumatosis cystoides intestinalis in an adult female patient undergoing chemotherapy for lymphoblastic crisis in chronic myelogenous leukemia. An impressive accumulation of gas was not only detected within the intestinal wall and mesentery but also in the peritoneum, retroperitoneum, mediastinum and cervical subcutaneous tissue. The patient was almost asymptomatic and fully recovered within a few days of treatment. In addition to chemotherapy, the patient was receiving trimethoprim/sulfamethoxazole for pneumocystis carinii pneumonia and lactulose for constipation. Mucosal damage due to chemotherapy and depletion of tetrahydrofolic acid, changes in bowel flora induced by antibiotic treatment, and the intake of unabsorbable carbohydrates may be responsible for the severity of the disease.

Continuous-wave and passively Q-switched cladding-pumped planar waveguide lasers.

Greater than 12 W of average output power has been generated from a diode-pumped Yb:YAG cladding-pumped planar waveguide laser. The laser radiation developed is linearly polarized and diffraction limited in the guiding dimension. A slope efficiency of 0.5 W/W with a peak optical-optical conversion efficiency of 0.31 W/W is achieved. In a related structure, greater than 8 W of Q -switched average output power has been generated from a Nd:YAG cladding-pumped planar waveguide laser by incorporation of a Cr(4+): YAG passive Q switch monolithically into the waveguide structure. Pulse widths of 3 ns and pulse-repetition frequencies as high as 80 kHz have been demonstrated. A slope efficiency of 0.28 W/W with a peak optical-optical conversion efficiency of 0.21 W/W is achieved.

Endoluminal repair of peripheral arterial aneurysms: 4-year experience with the cragg endopro system I.

PURPOSE: To assess the efficiency and long-term patency of the Cragg EndoPro System I in patients with peripheral arterial aneurysms. MATERIALS AND METHODS: In 10 patients, 13 stent-grafts were used to treat 15 arterial aneurysms. Aneurysms were located in the common iliac (n = 4), superficial femoral (n = 4), popliteal (n = 3), and subclavian arteries (n = 2), and in a femoropopliteal bypass-graft (n = 2). Follow-up ranged between 2 and 46 months (mean, 36 months). Examination included clinical status, color-coded duplex sonography, computed tomography angiography, and intra-arterial digital subtraction angiography (DSA). RESULTS: Technical success was achieved in all patients. Primary patency was four of four in iliac vessels and three of nine in non-iliac vessels; secondary patency in noniliac vessels was four of nine. Repairs included one local lysis, four percutaneous transluminal angioplasties, one surgical thrombectomy, and one bypass surgery. Stent wire disintegration was detected in one of four iliac stent-grafts and in seven of nine noniliac stent-grafts. In noniliac grafts, significant stenoses occurred in three of nine; occlusion occurred in five of nine. One complication at the iliac level was a vessel wall penetration at the proximal stent edge, with development of a new aneurysmal formation. No late endoleaks were found. CONCLUSION: Exclusion of peripheral arterial aneurysms with stent-grafts is feasible. Long-term results are excellent in iliac vessels. Mechanical weakness of the stent assembly and frequent re-stenoses or occlusions are significant drawbacks in noniliac vessels with low patency rates.

Improved control of nausea and emesis with a new bromazepam-containing ondansetron regimen in ovarian cancer patients receiving chemotherapy with carboplatin and cyclophosphamide.

BACKGROUND: Ondansetron was found to be effective as an antiemetic in numerous clinical trials of highly emetogenic combination-chemotherapy regimens that included cisplatin. Its role in milder emetogenic regimes has not been fully defined. METHODS: This study investigated the efficacy of two different antiemetic regimes in thirty-five patients with ovarian cancer receiving 68 cycles of chemotherapy with carboplatin (350 mg/m2) and cyclophosphamide (600 mg/m2). Ondansetron (3 x 8 mg i.v.) was compared to a bromazepam-containing ondansetron regimen. RESULTS: Nausea was absent in 65% of chemotherapy courses in patients receiving the combination of ondansetron and bromazepam and in 38% of chemotherapy courses in patients receiving ondansetron alone. Complete control of emesis was achieved in 93% of the courses in patients receiving the combination and in 81% of the courses using ondansetron alone. CONCLUSIONS: The addition of bromazepam to ondansetron, and the extension of antiemetic prophylaxis to the day before and the day after chemotherapy improves the control of nausea and emesis compared to ondansetron monotherapy in patients with ovarian cancer.

Myocardial contrast echocardiography for assessment of papaverine vasodilator response in patients with angiographically normal coronary arteries and in patients after orthotopic heart transplantation.

Myocardial contrast echocardiography has the potential for assessing changes in regional myocardial perfusion. We used this method to compare papaverine vasodilator response in 10 patients after orthotopic heart transplantation without acute rejection of left ventricular hypertrophy (HTX) and in 15 patients with angiographically normal coronary arteries (control group). Injections of 2 ml of sonicated iopromid (9 paired injections in HTX and 24 paired injections in the control group) were performed before and after intracoronary application of papaverine (8 or 10 mg) into the left or right coronary artery. From regional time-intensity curves, alpha (variable of curve width), area under the curve (area), peak contrast intensity (Imax) and contrast decay half-time (T1/2) were derived by from a gamma variate function. T1/2 increased from 4.2 +/- 1.2 to 7.2 +/- 4.0 s (p < 0.01) after papaverine in HTX compared to a change from 4.8 +/- 1.0 to 6.0 +/- 1.7 s (p < 0.001) in normal subjects. Alpha decreased in HTX from 0.44 +/- 0.15 to 0.27 +/- 0.10 s-1 (p < 0.01) after intracoronary papaverine injection. In the control group alpha was 0.37 +/- 0.08 s-1 at rest compared to 0.30 +/- 0.08 s-1 at hyperemic conditions (p < 0.002). Area increased in HTX from 444 +/- 261 to 910 +/- 732 U.s (p < 0.01) and in normal subjects from 352 +/- 171 to 585 +/- 262 U.s (p < 0.001). Hyperemic to baseline flow ratios for area varied from 0.9 to 3.8 (mean 2.17 +/- 1.11) in HTX compared to 1.76 +/- 0.52 (1.03 to 2.71) in normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

[Contrast echocardiography in the evaluation of myocardial flow reserve]. / Kontrastechokardiographie zur Beurteilung der myokardialen Flussreserve.

In order to determine whether changes in myocardial perfusion can be assessed by myocardial contrast echocardiography, intracoronary injections of 2 ml of sonicated iopromid were performed before and 30 to 45 s after application of papaverine in 31 patients (mean age 58 years). 13 patients showed coronary artery disease (KHE), 6 patients hypertensive heart disease (HHE), and 12 patients had no proven heart disease (KTR). Contrast decay-halftime (T/2), maximal video-intensity (Imax) and area under the curve (Area) were derived by computer-assisted videodensitometry. After papaverine KTR showed a significant increase of T/2 (from 5.1 +/- 1.5 to 6.8 +/- 3.2 s, p < 0.05), of Imax (from 36 +/- 13 to 52 +/- 16 E, p < 0.002) and of Area (from 203 +/- 95 to 379 +/- 188 E*s, p < 0.002) compared to baseline values. In this group the ratios of hyperemia to baseline flow conditions were 1.5 +/- 0.4 (from 1.0 to 2.4) for Imax and 1.9 +/- 0.9 (from 1.1 to 3.9) for Area. In HHE and KHE, hyperemia induced no significant changes of T/2, Imax and Area. Heart rate was increased by 4.3% and mean aortic pressure was decreased by 6.2% in all groups after papaverine. Double-product was not altered significantly in any group. Myocardial contrast echocardiography revealed a significant increase in variables of contrast wash-out curves only in patients without proven heart disease. In contrast, no relevant changes of T/2, Imax and Area on average were observed in patients with coronary and hypertensive heart disease. Thus, myocardial contrast echocardiography seems to be suitable to document a reduced papaverine vasodilator response in these patients.

Reproducibility of myocardial contrast echocardiography in human studies.

Experimental and clinical studies were performed to assess the ability of myocardial contrast echocardiography for quantitation of regional myocardial blood flow. To evaluate whether myocardial contrast echocardiography is a reproducible technique in humans, 18 nonselected patients undergoing coronary angiography were studied. A total of 107 intracoronary injections into either the left or the right coronary artery were analyzed by computer assisted videodensitometry for peak intensity, contrast decay half-time, and area under the curve. By means of these parameters intraobserver, interobserver, and interinjection variability were determined. Intraobserver measurements showed lowest variability with correlation coefficients of 0.83 for contrast decay half-time, 0.93 for peak intensity, and 0.95 for area under the curve. Mean percent error varied between 6.8% (peak intensity) and 11.2% (area under the curve). The correlation coefficients for interobserver variability ranged from 0.73 for area under the curve to 0.97 for peak intensity. Mean percent error revealed a range between 7.5% for peak intensity and 19% for area under the curve. For interinjection variability, the correlation coefficient for contrast decay half-time was lower (0.56) than for peak intensity (0.73) and area under the curve (0.84). Mean percent error were higher than for intraobserver and interobserver variability (range 24.1% to 34.2%). Thus, intraobserver and interobserver variability for parameters derived from time-intensity curves after intracoronary injection of echo contrast agent in humans are sufficient and comparable to data from animal studies. Interinjection variability, however, showed a higher mean percent error.(ABSTRACT TRUNCATED AT 250 WORDS)

[Myocardial contrast echocardiography for the follow-up after percutaneous transluminal coronary angioplasty]. / Myokardiale Kontrastechokardiographie zur Verlaufskontrolle nach perkutaner transluminaler Koronarangioplastie.

Myocardial contrast echocardiography was performed, before and after successful elective percutaneous transluminal angioplasty (PTCA) of a main coronary artery, in 35 patients (31 men, 4 women; mean age 56 +/- 6 years). After intracoronary injection of microbubbles-containing 2 ml iopromide, contrast half-life (t/2) and maximal echo-intensity (Imax) in the myocardial region supplied by the target vessel were measured. While t/2 decreased from 8.3 +/- 5.4 s to 5.7 +/- 3.3 s (P less than 0.0002), mean Imax remained unchanged (27.4 +/- 10.7 vs 26.1 +/- 10.1 grey value units). Repeat cardiac catheterization with contrast echocardiography was performed a mean of 37 weeks (7-53) later in 13 of 35 patients with optimal echo image quality. Re-stenosis of at least 75% was demonstrated in six patients, while in seven vessel diameter had decreased by less than 30%. In all patients with re-stenosis t/2 had increased by about 20 to 100% of the initial value. It was always over 5 s (mean 6.2 +/- 1.6 s before, 4.7 +/- 1.7 after PTCA, and 6.2 +/- 1.2 s at the end of the follow-up). In one patient a prolonged t/2 persisted due to vessel dissection. Mean t/2 remained unchanged in patients without re-stenosis (5.6 +/- 2.1 s before, 3.5 +/- 1.15 s immediately after PTCA, and 3.6 +/- 1.25 s at the follow-up examination). These data suggest that contrast half-life is suitable for demonstrating changes in myocardial perfusion after PTCA.

The IgA immune system in epileptics on anticonvulsant therapy.

Disturbances in IgA have often been reported in white epileptics on anticonvulsant therapy. The clinical significance of these disorders is of interest as this aspect does not appear to have been sufficiently explored. In a previous study neither African nor Caucasian epileptics on treatment showed a deficiency of serum IgA. Since secretory IgA is the main defence factor in protecting mucosal surfaces, the object of the present study was simultaneously to determine serum and salivary IgA in suitable subjects and to monitor related clinical events. A similar elevation of salivary IgA level was found in Black and White epileptics on treatment. Clinical events were rare and were not related either to serum or secretory IgA concentrations. It is concluded that at present epileptics do not seem to require special immunological or clinical monitoring.

IgA in epileptics receiving anticonvulsant therapy.

Epilepsy is a common disorder and requires long-term drug treatment. Epileptics on anticonvulsant therapy have often been reported to have a depressed immune system, especially an IgA deficiency. An association with clinical manifestations has not yet been clearly explored. So far investigations have been performed in Whites only. The objectives of this study were to assess if there is a racial difference in the immune response to anticonvulsants between Blacks and Whites and to establish the clinical significance of the IgA deficiency. Our results showed normal IgA values in Black and White epileptics on anticonvulsant therapy. This implies, at least at the present stage, that patients do not require immunological monitoring or protective measurements. Further studies including the determination of secretory IgA might help to explain the discrepancy between our findings and the literature and should provide deeper insight into the correlation between potential immune disturbances and clinical implications.