tance and vascular cell homeostasis were substantially

restored compared with C-Ap. At 3 months, M-Ap pre­vented restenotic lesion development and reset the inti­mal thromboresistance characteristics in places wherescars of dissection could not be detected.

CONCLUSIONS: Angioplasty with local delivery of mol­sidomine is feasible using a hydrogel-coated ballooncatheter in the atherosclerotic minipig. Molsidomine hassubstantial therapeutic effects attributable to the drug'spharmacologic properties.

Take Home Points:1. Angioplasty with local delivery of molsidomine is fea­

sible using a hydrogel-coated balloon catheter in theatherosclerotic minipig.

2. Molsidomine has substantial therapeutic effects attrib­utable to the drug's pharmacologic properties.

9:15 am

The Effect of Iodinated Contrast Media onNeutrophil Adherence to CulturedEndothelial Cellsx.x. Zhan, MD, Omaha. NE • D.K. Agrawal, PhD •

P.E. Thorpe, MD

PURPOSE: To determine if contrast media (CM) affectsneutrophil adhesion to endothelial cells (ECs).

MATERIALS AND METIlODS: Human umbilical vein ECswere incubated with 51Cr-labeled human neutrophils inthe presence of CM (diatrizoate, ioxaglate, iopamidol,and iodixanol) in three concentrations, 2, 20, 50

mgor1°mL-1. The responses were compared with iso­

osmolar glucose solutions. Neutrophil adhesion to ECmonolayer, EC structure, and cytotoxicity were evalu­ated.

RESULTS: Neutrophil adhesion significantly increased af­ter incubation in 2 mgor1omL-1 for 1 hour (P < .05) anddecreased in 50 mgor1omL-1 (P < .05). The correspond­ing glucose solution did not show any effect. All CM atmgor1omL-1 concentrations caused remarkable morpho­logic changes but not cell death. Diatrizoate and iox­agalate both had greater cytotoxic effected than did ECiodixanol and iopamidol.

CONCLUSIONS: A dose-related response was observed:Cell adhesion increased in lower concentrations and de­creased in higher concentrations of CM. This responsewas synergistic; it was not observed if ECs and neutro­phils were not exposed to CM simultaneously in a sharedenvironment. These effects may be due to CM chemo­toxicity because the corresponding glucose solution didnot effect similar changes at equal osmolar concentra­tions. Lack of cell death and altered neutrophil adhesionindicates modulation of cell adhesion molecules by CM.This could be pertinent to the pathogenesis of peripheralvascular lesions and endothelial response in patientswith immunosuppression or sepsis who receive CM.

Take Home Points: Contrast material may activate acellular response in both neutrophils and ECs and thusmodulate the expression or activation of cell adhesionmolecules.

Scientific Session 2Vascular ImagingModerator: John A Kaufman, MD Boston, MA

8:00 am

Endothelial Function in Contrast Medium-inducedNephrotoxicity

P. Drescher, MD, MS, Milwaukee, WI • D. Rauch, MD

• P.O. Ove, MD, PhD

PURPOSE: Endothelium plays a major role in regulatingvascular tone. We studied the influence of arterial endo­thelium in contrast media (CM)-induced renal vasocon­striction, an important factor in its occasional toxic effecton the kidneys.

MATERIALS AND METHODS: Isometric contractionswere studied in human and rabbit renal artery rings with

intact and denuded endothelium. The rings were stimu­lated with 1 j.lM phenylephrine as a control and increas­ing concentrations of the ionic CM diatrizoate, the non­ionic CM iohexol, and ioparnidol. To assess the pharma­cologic role of endothelium in CM-induced contractions,rings with intact and denuded endothelium were incu­bated with increasing concentrations of the nitric oxidesynthetase inhibitor Ng nitro-L-arginine methyl ester,which prevents endothelium-mediated vasomotor regu­lation, and with the nitric oxide-liberating substances

acetylcholine, molsidomine, and nitroprusside, which allenhance the endothelial effect on vascular smoothmuscle regulation.

RESULTS: Diatrizoate, iohexol, and iopamidol induceddose-dependent, reversible contractions of 35%, 20%,and 30%, respectively, of the phenylephrine control,with no difference between intact and denuded rings. Ng

nitro-L-arginine methyl ester had no effect on CM con­tractions. Contractions were inhibited dose dependently69%, 78%, and 55% by acetylcholine, molsidomine, andnitroprusside, respectively.

CONCLUSIONS: Our results show that CM-induced renalvasoconstriction is independent of the endothelium. Se­lective pharmacologic stimulation of the endothelium,however, may be useful to prevent CM-induced neph­rotoxicity.

Take Home Points:1. CM-induced renal vasoconstriction is independent of

the endothelium.

2. Selective pharmacologic stimulation of the endothe­lium may be useful to prevent CM-induced nephro­toxicity.

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8:15 am

Gadolinium-based Contrast Agents forAngiographic Use as a Safe Radiocontrast inPatients with Impaired Renal Functione.A. Bittner, MD, Los Angeles, CA • s.e. Goodwin, MD

• D. Lu, MD • TO. McNamata, MD • T joseph, MD

PURPOSE: To evaluate the potential of gadolinium­based contrast agents for use in angiographic proceduresin patients with impaired renal function.

MATERIALS AND METHODS: Five domestic swine un­derwent hepatic angiography with serial dilutions of 300mg/mL iohexol iodine contrast 000%, 50%, 25%, or12.5%), 0.5 mM/mL gadopentetate dimeglumine con­trast, and carbon dioxide angiography. All liquid contrastagents were power injected at 3 mUsecond for a totalvolume of 10 mL through a 5-F catheter. The'angiogramswere reviewed by four interventional radiologistsblinded to the protocol to determine the degree of ana­tomic detail demonstrated and the overall quality of con­trast agents compared with one another.

RESULTS: The overall quality and demonstration of ana­tomic detail found in angiograms performed with 0.5mM/mL gadopentetate dimeglumine contrast was foundconsistently to be comparable to 25% to 12.5% dilutionof the iodine-based contrast and to be superior to carbondioxide angiography.

CONCLUSIONS: Given the well-documented safety pro­file of gadolinium, it may be a clinically useful radiocon­trast agent in patients with impaired renal function.

Take Home Points:1. Gadolinium-based contrasts can produce clinically

useful angiograms that may be superior to carbondioxide angiography.

2. Gadolinium would be a safe radiocontrast agent inpatients with impaired renal function.

3. Higher concentrations of gadopentetate dimegluminemay yield improved angiographic results.

8:30 am

Computed Tomographic Angiographic Findingsof Aorta and Disease Activity in Takayasu Arteritis].H Park, Seoul, Korea • HS. Park .].W. Chung •

YB. Park • M.e. Han

PURPOSE: To analyze computed tomographic (Cn an­giographic findings of aorta in Takayasu arteritis andcorrelate them with disease activity.

MATERIALS AND METHODS: The participants were 40patients with Takayasu arteritis. There were 37 womenand 3 men, and their mean age was 38 years. The diseasewas clinically active in 25 patients and inactive in 15patients. The criterion of activity was erythrocyte sedi­mentation rate > 20 mm/hour. Spiral CT angiographywas performed to obtain transaxial images of the aorta in

three phases: before enhancement, arterial, and delayed.The mural findings of the aorta were analyzed by threeradiologists to correlate them with activity of the disease.Statistical analysis was performed using the chi-squaredtest and the Fisher exact test.

RESULTS: The CT angiographic findings before enhance­ment were high-attenuation ring (n = 26) and mural cal­cification (n = 30). Mural thickening (n = 38) was ob­served during the arterial phase. Delayed enhancement(n = 30) and low-attenuation ring (n = 12) were ob­served in the delayed phase. The characteristic findingsamong the 25 patients with active disease were earlyenhancement (n = 16) and low-attenuation ring (n = 5)during the arterial phase, and delayed enhancement (n =22), and low-attenuation ring (n = 12) during the delayedphase. Compared with the findings in 15 patients withinactive disease, early and delayed enhancement andlow-attenuation ring in the delayed phase were ob­served more frequently in 25 patients with active disease(P < .00l)

CONCLUSIONS: CT angiography shows characteristicmural findings in the aorta in persons with Takayasuarteritis. Those findings are closely correlated with clini­cal disease activity.

Take Home Points: Spiral CT angiography shows char­acteristic mural thickening of the aorta with variable en­hancement in persons with Takayasu arteritis. The find­ings suggestive of active disease are early and delayedenhancement and low-attenuation ring inside the aorticlumen.

8:45 am

Utility of Electron-Beam Computed Tomographyto Detect Pulmonary Embolisms: Validation in aPorcine ModelH Yoon, MD, PhD, Salt Lake City, UT.]. Goldin, MD,

PhD • L.D. Greesert, BS • EX. Nishimura, MD •D. Aberle, MD

PURPOSE: To determine the sensitivity of electron-beamCT (EBCn to detect pulmonary artery embolism in aporcine model.

MATERIALS AND METHODS: Under general anesthesia,four segmental branch pulmonary arteries in each of fiveswine were selectively catheterized and obstructed withgelfoam pledgetts. Emboli were confirmed by contrastangiography. Contrast-enhanced scans of the pulmonaryarteries were performed using a Siemens C-lOO EBCTscanner (Iselin, NJ) immediately after the angiogramswere taken. An imaging time of 100 ms/slice was used.Images of the pulmonary arteries were obtained with3-mm collimation. Cardiac-gated and nongated scanswere performed. Contrast injection was performed at 2or 3 mUs for a total of 60 mL for each scan. Table travelvaried between 2 and 3 mm/slice. Breath holding duringgated scans was not possible in these animals.

RESULTS: Contrast-enhanced EBCT scans permitted cor­rect identification of 18 of 20 emboli in the segmentalbranches of the pulmonary arteries for an overall sensi­tivity rate of 90%. Cardiac gating subjectively improvedimage quality but did not result in greater sensitivity fordetecting pulmonary emboli. Breath holding was notnecessary to achieve this high sensitivity.

CONCLUSION: Contrast-enhanced EBCT is a sensitivemethod to detect segmental pulmonary artery embolism.

Take Home Points:1. Contrast-enhanced EBCT is a sensitive method to de­

tect segmental pulmonary embolism.

2. Cardiac gating does not improve the sensitivity of thistechnique.

3. Breath-hold imaging is not necessary to achieve thishigh sensitivity.

9:00 am

Low-Dose Gadolinium-diethylene-triamine­pentaacetic Acid Dynamic Magnetic ResonanceImaging of Intravascular Stents

R. Tello, MD, MSME, • Boston, MA • K.R. Thomson, MD,

CHB • D. Witte, FIR • Gj. Becker, MD • B.M. Tress,MD

PURPOSE: Magnetic resonance (MR) contrast enhance­ment depends on the timing of image acquisition. Hu­man trials have shown efficacy of renal artery stents withsalvage of renal function. This study assessed the abilityof dynamic gadolinium-diethylene-triamine-pentaaceticacid (Gd-DTPA) to demonstrate renal and iliac arterystent patency compared with conventional angiographyas the gold standard.

METHODS: Eight persons with nine stents who werereferred for angiography underwent dynamic MR stud­ies, including seven with renal artery stenting (PalmazP204 or P201; Johnson & Johnson, Sydney, Australia)and one with an iliac stent. All were examined with con­ventional angiography and after dynamic Gd-DTPA in­fusion. Coronal MR images were acquired using a GESigna 15T magnet (Fast-spoiled Gradient Echo [FSPGR];TE = 4.2, TR = 68-150, flip = 75°) 0 to 600 seconds after0.1 mM/kg Gd-DTPA IV bolus injection during sequen­tial breath-hold acquisitions lasting 13 to 32 second each.

RESULTS: All nine stents were visualized with 100% ac­curate patency documentation.

CONCLUSION: FSPGR MR imaging with bolus Gd-DTPAadministration can provide adequate time and spatialresolution to demonstrate arterial stent patency.

Take Home Points: FSPGR echo MR imaging with bo­lus Gd-DTPA administration at 0.1 mM/kg can provideadequate time and spatial resolution to demonstrate ar­terial stent patency.

9:15 am

Evaluation of Neointima Proliferation and PlaqueStructure in Covered versus Uncovered NitinolStents with Intravascular UltrasoundH. Schwarzenberg, MD, Kiel, Germany • S.

Milller-HiUsbeck, MD • j. Brossmann, MD • M. Heller,

MD

PURPOSE: To evaluate neointima formation and plaquecomposition in covered (CNS) versus uncovered nitinol(UCNS) stents with intravascular ultrasound (IVUS).

MATERiALS AND METHODS: Twelve pelvic UCNSs (9.4± 1.1 mm diameter, 53 ± 19.6 mm length) in 10 patientsand 19 CNSs (4 pelvic, 15 femoral stents; 65 ± 1.6 diam­eter, 64.2 ± 28.9 mm length) in 12 patients were evalu­ated with IVUS at 12.3 ± 6.4 months (UCNS) and 10.3 ±5.6 months (CNS) after implantation. Maximum thick­ness and the area of neointima were measured. Qualita­tive analysis of plaque composition and lesion topogra­phy were also assessed.

RESULTS: Maximum stenoses of 15.1 ± 9.1% in UCNS and435 ± 26% in CNS (P < .01) were found. Maximumplaque area was 8.2 ± 6.6 mm2 (UCNS) and 25.4 ± 15.8mm2 (CNS) (P < .01). In both stent types, neointimalplaques were predominately soft and eccentric.

CONCLUSIONS: CNS showed significantly larger plaqueareas and higher graded stenoses compared with UCNS.Eccentric soft lesions are preferred in both stent types.

Take Home Points: IVUS revealed larger plaque areasand higher graded stenoses in CNSs compared withUCNSs. Eccentric soft lesions are preferred in both stenttypes.

Scientific Session 3TIPSModerator: Jeanne LaBerge, MD, San Francisco, CA

8:00 am

Treatment of Budd-chiari Syndrome with theTransjugular Intrahepatic Portosystemic ShuntZj. Haskal, MD, Philadelphia, PA • j. Weintraub, MD

PURPOSE: Use of transjugular intrahepatic portosystemicshunt (TIPS) to treat Budd-Chiari syndrome (BCS) hasgenerally been considered investigational. We evaluatedthe role of TIPS for this indication.

MATERiALS AND METHODS: Five women, ages 22-37years, with subacute (n = 4) or fulminant (n = 1) BCSunderwent TIPS placement. BCS was caused by polycy­themia vera in three, and it was idiopathic in two pa­tients. All had severe to massive ascites, and three hadmoderate or severe lower extremity edema.

RESULTS: BCS was confirmed by contrast/carbon diox­ide venography and transjugular biopsy. Portosystemicgradients were reduced from a mean of 34 mmHg

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