Cardiovasc InterventRadiol (1997) 20:239-247

CardioVascular and Interventional Radiology 9 Springer-Verlag New York Inc. 1997

CIRSE '96 Summary Report Proceedings of the Annual Meeting of CIRSE Madeira, Funchal, September 8-12, 1996 Robert F. Dondelinger, Liege, Belgium Chairman of Program Committee A total of 313 oral presentations and 82 posters comprised the program of the annual meeting of CIRSE. Main highlights of the meeting were Interventional MRI; Aortic Stent Grafting; MRI and CT Vascular Imaging; TIPS and Portal Vein Interventions; Catheter Management of Gastrointestinal Hemorrhage and Trauma; Liver Tumors; Bone Interventions; Pain Therapy; and Vena Cava Filters. The most prominent features of the meeting are summarized here. Abstracts listed below refer to Cardiovascular and Interventional Radiology 19[Suppl 2], 1996.

Arterial Interventions: Angioplasty and Related Techniques Dierk Vorwerk (Aachen, Germany) More than 90 papers, six workshops, and five state-ofthe-art lectures covered the topic of arterial interventions, presenting angioplasty and related techniques. Experimental work predominantly dealt with experiments on neointimal hyperplasia or tumor ingrowth, comparing different types of stents, using antineoplastic agents attached to the stent surface and coatings. Combining different alloys to cause electrolytic effects along the stent surface was successful in reducing tissue ingrowth (Abstracts 1, 3, 4, 6). An interesting animal model for aortic aneurysms (AAA) was presented that is closer to the real pathophysiological situation and keeps lumbar arteries open, which is a major prerequisite for studying problems of collateral perfusion of the aneurysm even after exclusion (Abstract 5). A complete session was dedicated to the use of aortic stent grafts in the treatment of AAA (Abstracts 13-21). A larger patient population followed after placement of the Stentor composite graft was presented by several groups from Germany and Austria, showing consolidated results with good technical success, sufficient follow-up results, and a certain rate of late leakage. Post-implantation syndrome turned out to be a still frequent sequela of unknown origin with this type of Dacron prosthesis. No recent results were available on the new design after the change of manufacturer from Mintec to Boston Scientific. One group reported rup-

ture of sutures within the stent body that occurred during follow-up (Abstract 17). Results with other devices such as the EVT prosthesis and the Corvita tube graft, and other individual designs such as from the Maim6 group and the Stanford group, were presented on smaller numbers. Regarding arterial stenting, a large number of papers dealt with the use of various stent types in aortoiliac bifurcation and iliac occlusions, indicating no surprisingly different results with new types of stents as compared with known data for the Palmaz stent and Wallstent (Abstracts 40-51). Another session predominantly discussed use of covered stents in iliac and femoral lesions. Covered Dacron stents showed high patency in iliac arteries (Abstracts 132, 136). There are diverging results for their use in femoral lesions. While two papers reported fairly encouraging patencies of more than 60% after 2 years (Abstract 129), other authors found marked restenosis in a high number of cases (Abstracts 135,277) with a 6-month patency of 35% and 25% (Abstracts 277, 278). This excessive neointimal growth has also been proved by animal experiments (Abstracts 3, 134). Morphological changes related to the post-implantation syndrome were monitored by MRI, showing fairly extensive perigraft edema up to 4 weeks after implantation (Abstract 279). It remains to be determined what role there is for covered stents besides exclusion of aneurysms. Comparison of primary stenting versus percutaneous transluminal angioplasty (PTA) in femoropopliteal lesions did not find a benefit for stenting but a higher occlusion rate after stent placement

240 (Abstract 280). An interesting paper defined selection criteria for out-patient PTA, finding one third of patients suitable for this approach (Abstract 238). The subject will definitely be of further interest from an economic point of view. In renal artery disease, several papers dealt with the benefit of stenting over PTA for the treatment of ostial disease (Abstracts 98-102), stating that primary stenting should be recommended for this type of lesion; success rates were not improved compared with a general population of renal arterial stenosis. An interesting paper tested 10-year patency of renal arteries after PTA, showing a high rate of relapse of hypertension despite fully patent renal arteries (Abstract 104). Regarding recanalization techniques, one complete session covered thrombolysis and clot dissolution. A number of theoretical and clinical papers dealt with pulse-spray lysis, again stating a high technical success of the procedure (Abstracts 92-94). Partial recanalization causing distal embolization after succeeding PTA was described as the most relevant complication in up to 22% of cases (Abstract 93). Several other papers (Abstracts 95-97) described clinical and experimental results with hydrodynamic thrombectomy and mechanical clot dissolution in arterial thrombosis, showing promising results in most cases even in lower limb ischemia. However, in most instances additional interventions were required to complete the procedure. In conclusion, arterial interventions were again dominated by stent technique in aortoiliac disease. The presentations mainly included consolidation of data rather than genuinely new approaches or breakthroughs. Clinical experience with mechanical and mechanically accelerated thrombectomy techniques is becoming available from more centers, stating the feasibility of this concept for arterial applications also.

Venous and Pulmonary Interventions

Christoph Zollikofer (Winterthur, Switzerland) The scientific sessions on venous and pulmonary interventions included one 2-hour session on venous and pulmonary interventions (Abstracts 78-90). A further five abstracts dealt with diagnosis and treatment of varicoceles or incompetent ovarian vein (Abstracts 184, 185, 191-193). Finally, six presentations addressed the application of venous stents (Abstracts 263-267,303). Three papers dealt with central venous line access, stressing the point that it is a safe procedure even on an outpatient basis (Abstracts 80, 82, 90). One paper additionally pointed out the increased safety and success rate using ultrasound as a guiding tool (Abstract 90). A method for safe recanalization of occluded major central veins by way of guidewires for subsequent

CIRSE '96 SummaryReport central venous line placement was described (Abstract 78). Success was achieved in all patients and the method was suggested as an alternative to a translumbar, intercostal, or intrahepatic approach. A new implantable catheter port system (PIPS) was described, which can be implanted by interventional techniques. First clinical experiences with intraarterial infusion of cytostatic drugs have been promising (Abstract 81). Two papers described preliminary experiences with "breathhold" gadolinium-enhanced pulmonary MR angiography (Abstracts 84, 87). Using fast gradient hardware, pulmonary emboli may be identified as peripheral as in segmental branches and a masked comparison between MR angiography and pulmonary arteriography demonstrated a 100% sensitivity in the first preliminary study. Mortality, morbidity, and adequacy for anticoagulant therapy with associated costs using various strategies of invasive and noninvasive diagnostic tests were calculated. The authors defined three distinct groups. Group B (pulmonary angiography with or without prior perfusion-ventilation lung scans and ultrasonography of the legs) had a low mortality and morbidity rate with cost savings of approximately 40% and inappropriate therapy in less than 5% of cases. The authors concluded that an optimal diagnostic management strategy for pulmonary emboli should include pulmonary angiography. Furthermore perfusion-ventilation lung scans and ultrasonography of the legs reduced the number of patients requiring pulmonary angiography by 40%50% and proved to be cost effective. The value of spiral CT for detection of central pulmonary emboli as a cause of acute pulmonary hemoptysis was addressed before transcatheter bronchial embolization (Abstract 86). In 3 of 22 cases with acute hemoptysis, pulmonary embolism was found as the underlying cause proven by angiography. The authors concluded that spiral CT should be performed in all patients with acute hemoptysis before bronchial angiography and eventual embolization to rule out pulmonary emboli. First results with the Amplatz thrombectomy device were presented in 5 patients representing a high-risk group (Abstract 83). Good pulmonary reperfusion was achieved in only 1 patient and moderate improvement in 3 patients. The device seems to be effective in fresh clot; however, in chronic organized pulmonary embolism or older emboli the device proved not as effective as had been hoped. Catheter-directed thrombolysis for deep vein thrombosis (DVT) of the iliofemoral axis in order to reduce subsequent post-thrombotic syndrome was suggested (Abstract 88). With an average dose of 5.6 Mio units of urokinase over 2 days iliofemoral patency was achieved in 83% of cases. In half the patients stents were implanted to speed up the procedure in residual

CIRSE '96 SummaryReport venous stenosis. At follow-up a trend to less venous outflow obstruction and less venous reflux was seen. The combined treatment of sclerosing agents and embolization proved to have a 100% success rate in a prospective randomized study. By comparison two other groups of 15 patients, who each received embolization or sclerotherapy alone, had one and two relapses respectively (Abstract 184). In a second paper, spermatic vein embolization using microcoils in a distal position at the level of the inguinal ligament resulted in a 6% recurrence rate (Abstract 192). No relapse was seen after a follow-up period of 6 - 4 8 months in 17 pediatric patients (age 8 - 1 4 years) using a combination of Gelfoam plugs, hypertonic glucose, and 3% aetoxysclerol (Abstract 193). It was noteworthy that 13 of the 17 patients also had right internal spermatic vein insufficiency which was also treated. The correlation between selective spermatic vein phlebography and Doppler sonography was addressed. The study confirmed a high predictive positive value of Doppler sonography for subclinical varicoceles with no dilation of the pampiniform plexus on high-resolution ultrasound (Abstract 191). The results of ovarian vein embolization for chronic pelvic congestive syndrome were reported in 22 patients. Ten patients had significant or complete pain relief whereas 6 patients noted partial relief and 6 had little or no improvement (Abstract 185). In two papers, the use of the Palmaz stent for the treatment of malignant superior vena cava (SVC) syndrome was described with technical success in 9 4 % 100% of cases and no procedure-related complications (Abstracts 263,266). The indications for a Palmaz stent in lesions which needed more than 70 p.s.i, were discussed before the stenosis reopened on an exploratory balloon dilatation (Abstract 266). Others used Wallstents for subclavian and brachiocephalic veins of 1 0 14 nun diameter and Gianturco-R6sch stents of 2 5 - 3 0 mm diameter for the SVC in 26 patients with malignant SVC syndrome. Seventy-three percent of patients showed total and 17% partial relief of their symptoms (Abstract 264). Surgically induced suprarenal vena cava stenoses were successfully dilated with extra-large Palmaz stents of 18 mm diameter in 10 of 11 pigs (Abstract 265). There was one stent migration, and two stents where no anticoagulation was administered were occluded at 4 weeks follow-up. In all 8 pigs that had received anticoagulant therapy the vena cava remained patent. The authors concluded that extralarge Palmaz stents could overcome surgically induced fibrotic caval stenosis and remain open if anticoagulants are given. Treatment of pelvic venous spur (May-Thurner syndrome) with Wallstents as the method of choice was advocated. Seven patients with symptomatic spurs

241 (left DVT or post-thrombotic leg swelling) had been successfully treated with a 100% patency rate during the follow-up period of 1-112 months (average 29 months) (Abstract 303). The accuracy of MR venography, mediastinal phlebography and CT were prospectively compared in 13 patients with malignant SVC syndrome prior to stent placement. MR venography proved to have the highest sensitivity and specificity of 96% and 100% respectively. The authors concluded this to be the best modality for planning stent placement in malignant SVC syndrome (Abstract 267).

Embolization and Oncology Mario Bezzi (Rome, Italy) The sessions on liver tumors and oncological interventions covered various aspects, including hepatic artery infusion techniques and percutaneous ablation techniques (Abstracts 108-116, 176-183). Experience with short-term (average 4 days) percutaneous hepatic artery infusion using a left brachial artery approach was reported. Catheter placement was possible in 100% of cases, despite anatomical variants. Although systemic anticoagulation was not used, no thromboembolic complications were observed, and the use of the brachial approach enhanced patient tolerance of the procedure (Abstract 108). Permanent implantation of a catheter for hepatic arterial chemotherapy was reported by two groups. One presentation focused on the technical aspects (Abstract 109). Using a subclavian artery approach, a 0.035-inch end-hole catheter was inserted into the hepatic artery, and so was able to re-establish arterial infusion in 30 patients with dislocated surgically inserted catheters. Major complications included hepatic artery thrombosis (5 cases, 3 of them reversible with lysis and 2 with definitive termination of the therapy; leak at the level of the connection between the catheter and the subcutaneous infusion port in 11 cases). This problem has subsequently been resolved by modifying the connection. Experience with patients affected by advanced hepatocellular carcinoma (HCC) was reported (Abstract 110). A percutaneously implantable port system was used, administering the drugs in two cycles (FAM followed by EEP). The response rate was 48%, with a survival rate at 4 years of 12%. The major drawback of the treatment was the myelosuppression experienced by many patients. Three papers dealt with the clinical results of chemoembolization (TACE) of HCC. Abstract 112 reported on TACE as neo-adjuvant therapy, used to diminish the rate of tumor recurrence in patients who receive liver transplantation for HCC. In a group of 15 patients tumor recurrence and death was seen in

242 2 cases, while tumor necrosis >50% was observed in 10 of 15 livers. Four patients (27%) died of infectious complications within 40 days after transplantation; this high rate of sepsis after TACE and liver transplantation, although noteworthy, remains unexplained. In a similar study (Abstract 177) TACE was employed alone or in combination with intratumoral ethanol injection. It was noticed that recurrence after transplantation occurred only in patients in whom viable tumor tissue was still present in the treated tumor. The same group (Abstract 182), by studying the liver obtained at transplantation, demonstrated that CT performed after TACE (lipiodolCT) has a poor accuracy in detecting foci of HCC (sensitivity 73%, specificity 59%). The importance of segmental TACE, using anticancer drugs and lipiodol, was shown (Abstract 114). In tumors smaller than 3 cm, the survival rate was 83% at 3 years and 57% at 5 years. The necrotizing effect of TACE can be increased by further chemoembolization or by intratumoral injection of hot saline solution. Pharmacokinetics of lipiodol were also investigated, and one paper tried to standardize the type of emulsion to be used in TACE (Abstract 176). In an animal model (rabbits with VX2 liver tumors) several types of water and oil emulsion were tested. The results showed that large water-in-oil emulsions reduce lung uptake and yield a higher ratio of tumor to nontumorous liver lipiodol uptake. Another presentation analyzed the potential role of intratumoral injection of cytostatics in murine liver metastases (Abstract 178). It was found that mitomycin reduces tumor growth more than ethanol, and that the use of hyaluronidase does not enhance this effect. Percutaneous liver tumor ablation by physical agents was addressed by three papers. Two dealt with the technical refinement of electrodes for radiofrequency ablation (Abstracts 115, 116). Another paper reported preliminary results on the treatment of liver tumors with microwaves (Abstract 180). The best results were obtained in patients with HCC who showed no evidence of tumor during followup, while patients with metastases responded in 50% of cases only. Although the technique might be promising, longer follow-up is necessary. TIPS and Portal Vein Interventions

Jose I. Bilbao, (Pamplona, Spain) Papers on TIPS fall into three categories: general series, management of complications of TIPS, and technical aspects and results of TIPS in specific groups.

General Series The session began with the presentation of a series of 723 TIPS performed in one center (Abstract 22). The

CIRSE '96 SummaryReport experience of these authors showed how the initial indications broadened (to include portal thrombosis and Budd-Chiari syndromes) when good results were obtained. In this series, early mortality (1 month) was 3%. This mortality rate was, however, much higher (24% at 3 months) in Child B or C patients in whom TIPS was performed in an emergency operation after failure to control hemorrhage by sclerotherapy or banding (Abstract 26). The causes of death were multisystemic failure, complications of sclerotherapy (esophageal perforation), and sepsis. Various factors were shown to be responsible for a significantly lower survival (Abstract 27). Among these were portal pressure greater than 30 mmHg, ascites, albumin lower than 3 g/dl, Child class, WBC count under 7,000, and bilirubinemia of over 3 mg/dl.

Management of Complications of TIPS Several authors presented the primary and secondary patency of TIPS (Abstracts 23-25). Primary patency was 53% after 2 years, and secondary patency ranged from 75% to 86% for a similar follow-up period. It is striking that 100% of the Child A patients required some kind of re-intervention in the first 2 years of follow-up. As color Doppler ultrasound was shown to be reliable in the detection of stenosis in follow-up of TIPS, the flow readings should be taken in the intraparenchymatous stretch of the shunt (Abstract 65). A new treatment to prevent intra-shunt restenosis was presented (Abstract 29). Once the stenotic shunt is catheterized, radiotherapy is given "in situ" at 12 Gy for 15 min, and then the lesion is dilated using a balloon. Little experience is yet available, but over the 1-year follow-up period no further stenosis appeared. By using reductive prostheses, a significant reduction in the rates of encephalopathy was achieved and a marked drop in the level of ammonium was observed, while bilirubinemia remained steady (Abstract 28).

Technical Aspects and Results of TIPS in Specific Groups Given the good survival rate obtained in Japan with chemoembolization (TACE) in the treatment of hepatocarcinoma, the presence of a tumor is not an exclusion criterion for TIPS and TIPS should be performed 3 months after TACE (Abstract 27). However, it is not clear whether this treatment protocol increases the rate of pulmonary metastasis. Two series showed the application of TIPS in pediatric patients (18 patients, 15 of whom had biliary atresia) (Abstracts 52, 53). The initial success rate was 86% in one series, due to changes in the morphology and arrangement of the hepatic veins. The prostheses implanted had a caliber of

CIRSE '96 SummaryReport 6-8 ram. Due to the correct functioning of the TIPS two patients were removed from the waiting list for orthotopic liver transplantation. In patients with recent thrombosis of the portal vein (within the last 14 months), the procedure was carried out in all 11 cases without using ultrasound guidance for the puncture; the thrombus cleared up without the need for thrombolysis (Abstract 55). Although some controversy still surrounds this, where there is persistent hepatofugal flow caused by varices, even if the TIPS is patent, embolization of all the collaterals is recommended before the placement of a second parallel TIPS or overdilatation of the prosthesis (Abstract 58). Among the techniques used for guiding the needle in portal puncture, the intraportal transparietohepatic insertion of a 0.018-inch guidewire is recommended (Abstract 57). If CO2 is injected as the needle is moved forward, the puncture of a biliary radicle is detected (with a presumable higher risk of re-stenosis), which means that the needle can be relocated in a safer portal branch (Abstract 64). In cases of extrahepatic puncture of the porta, the insertion of a stent-graft may be indicated, although it has also been suggested that a further portal puncture should be performed (Abstract 59). Several series presented the results obtained when using metal prostheses and angioplasty in stenosis and short obstruction of the portal vein (Abstracts 56, 60, 61). The initial results were favorable, although it is necessary to wait for longer-term follow-up in benign stenosis. Finally, the outcome obtained with direct fibrinolysis in acute and chronic thrombosis of the portal vein was described (Abstract 61). For the former, this technique offers excellent results, while for the latter, although the outcome is positive, no case of complete lysis was achieved.

Vascular Imaging and Contrast Media

Peter E. Huppert (Tiibingen, Germany)

243 duced marked platelet degranulation, which was caused by neither ionic nor nonionic dimers (Abstract 201). Nonionic dimeric iodixanol (270 mg I/ ml) and monomeric iopromide (300 mg I/ml) provided equivalent diagnostic information during femoral digital subtraction angiography (DSA), whereas the frequency of painful adverse effects was significantly lower in the iodixanol group (0.9% vs 9.5%) (Abstract 202). Another study demonstrated sufficient diagnostic quality of peripheral runoff angiography if a volume of only 75 ml of a 30% ionic CM was injected via a specially designed aortic flush catheter (Abstract 206).

Cardiac Imaging Two papers reported on the implementation of new MRI modalities. Using a multishot segmented fatsuppressed echoplanar sequence, breathhold 3D MR angiography of proximal coronary artery segments was feasible in volunteers. Vessel delineation was impaired if perivascular fat was reduced and if the heart rate was elevated (Abstract 32). Another paper demonstrated successful assessment of myocardial function and perfusion during breathhold in corresponding regions of the left ventricle, if segmented FISP 2D cine sequences and inversion recovery Turbo FLASH 2D sequences, respectively, were used (Abstract 34). Spiral CT and MR! of coronary bypass grafts during the early postoperative period was presented in two studies showing that cross-sectional imaging provides reliable information for differentiating patency and occlusion of aortocoronary venous grafts (Abstract 39) and aortoatrial PTFE grafts (Abstract 37). However, imaging of arterial grafts was successful in < 70% of cases (Abstract 39), and the visualization of graft anastomoses was insufficient by any technique. The value of standard MRI techniques at 0.5 T was demonstrated in patients with tetralogy of Fallot and anomalies of great vessels (Abstracts 365, 366).

Contrast Media (CM) Eight papers (2%) presented CM research. Four gave experimental data contributing to the pathophysiology and protection from CM-induced nephropathy. Chronic hypertensive nephropathy and a decrease in oxygen tension in the renal cortex and outer medulla are probably important cofactors. The adenosine receptor antagonist theophylline, as well as furosemide, showed significant protective effects (Abstracts 199, 200, 204, 205). The second group of papers presented findings which added some weight to the idea that nonionic dimers are the CM of choice for vascular interventional procedures. Under in vitro conditions, the nonionic monomeric iopromide in-

Vascular Imaging Forty-four presentations (11%) reported on vascular imaging. The majority concerned MR angiography, spiral CT, and ultrasound. Eleven studies discussed new imaging modalities before and after interventions in the aorta and peripheral arteries. Two presentations (Abstracts 41,346) demonstrated tailored spiral CT to be useful for planning of stent graft repair in aortic aneurysms and during follow-up of these patients. The detection rate of ostial stenoses >70% in renal and mesenteric arteries was >80%. For imaging of peripheral arteries similar results

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were reported using conventional MR angiography and contrast-enhanced MR angiography respectively. With magnitude and ECG-gated phase contrast MR angiography, the sensitivity (specificity) in grading of stenoses was 94% (96%). Phase contrast provided superior visualization of atherosclerotic lesions before treatment, while magnitude contrast better demonstrated patency thereafter (Abstract 31). Using triple-dose contrast-enhanced MR angiography (0.3 mmol Gd-DTPA/kg, 3D time-offlight), the sensitivity (specificity) in depicting femoral stenoses >50% was 97% (86%) (Abstract 33). For detection and grading of popliteal artery entrapment, non-contrast-enhanced MR angiography seems to be of limited benefit (Abstract 222). The value of high-resolution cross-sectional MRI in peripheral vascular disease was the topic of a further two studies. In conventional systems, spatial resolution strongly depended on the gradient field strength. At 25 mT/m the pixel size was 2 0 0 - 2 9 0 #m, and nearly 20-fold lower, compared with 6 mT/ m (Abstract 38). Another study demonstrated the electro-mechanical feasibility of catheter-based endoluminal NM imaging in vitro and in vivo (Abstract 35). MRI and spiral CT of renal arteries were discussed in two papers. The intention to visualize the peripheral segment of renal arteries by a contrast-enhanced (0.4 mmol Gd-DOTA/kg) fast gradient echo technique succeeded in only 80% of cases (Abstract 105). For spiral CT the sensitivity (specificity) in depicting stenoses > 75% was 97% (92%), although it must be added that the diagnostic accuracy depended on the reader's expertise (Abstract 106). The value of contrast-enhanced fast gradient echo sequences for visualization of pulmonary circulation and pulmonary embolism was shown. Fifth- and sixthorder branches of the pulmonary vascular tree and all angiographically proven emboli were depicted (Abstracts 84, 87). MR angiography and spiral CT angiography were also studied in several other vascular territories. Spiral CT angiography was useful for detecting high-grade carotid artery stenoses (Abstract 319) and basilar artery occlusions (poster 341). MR angiography combined with MRI provided sufficient information for stent placement in malignant mediastinal vein obstructions (Abstract 267). For preoperative staging of pancreatic cancer, spiral CT will probably replace arteriography in the near future, which was demonstrated by three studies (Abstracts 36, 260, 261). The value of Doppler ultrasound was demonstrated in patients with suspected vascular pathology of the upper extremity (poster 355), during follow-up after PTA of femoral arteries (Abstract 252) and in patients with suspected arteriogenic impotence (Abstract 246).

CIRSE '96 Summary Report

Biliary Interventions

Christoph Becker (Geneva, Switzerland) As in previous years the main focus of the scientific papers presented on the topic of biliary intervention was metallic stents. Clinical results with polyurethanecoated Wallstents in 22 patients with malignant biliary obstruction were presented (Abstract 147). Primary and "assisted" patency rates at 3, 6, and 9 months were 72%, 46% and 46%, and 89%, 69% and 69%, respectively. Cholangioscopy was used to assess the stent lumen in patients who presented with occlusion. It was concluded that covering cannot prevent stent occlusion or improve long-term patency, and that the mechanisms leading to occlusion in covered stents need further investigation. Cholangioscopic findings as seen in both covered and uncovered Wallstents in 15 patients were presented (Abstract 148). Incorporation of the metallic filaments into the ductal wall was incomplete in the vast majority of cases even after 55 months, and the free metallic surface was suggested as a possible mechanism for stone formation. Both granulation tissue and tumor tissue, probably resulting from tumor ingrowth, were seen in patients with covered stents. A work-inprogress paper (Abstract 6) evaluated the ability of stent coating with a slow-release angiogenesis inhibitor bound to ethylene-vinyl-acetate to prevent reactive bile duct tissue overgrowth and malignant ingrowth. In an experimental study, metallic stents with and without coating were implanted in the bile ducts of 41 domestic pigs and in 22 rats with implanted tumor-deposits. Stent coating with angiogenesis inhibitor was effective in preventing benign granulation tissue in the pig model and tumor ingrowth into the stent lumen in the rat tumor model. Several papers reported results of percutaneous radiological treatment of benign biliary strictures. Either percutaneous balloon dilatation or metal stent placement was done in a series of 58 patients (Abstract 142). Thirty-two patients had anastomotic stenoses, 15 had postoperative bile duct stenoses, and 11 patients had inflammatory stenoses. The 2-year patency rate was 71% after balloon dilatation and 84% after stenting (p = 0.1). Recurrent stenoses were diagnosed after a mean period of 667 and 501 days, respectively. It was concluded that both methods may be used successfully. Another study evaluating the effectiveness of metallic stenting in 20 patients with benign biliary obstruction was reported (Abstract 144). Four patients had stenoses at biliodigestive anastomoses, 10 patients had postsurgical bile duct stenoses, and 6 patients had inflammatory stenoses. The mean follow-up period was 31.2 (___4.5 months). Stent occlusion was observed in 10 patients after 3-55 months, and 4 of the other 10 patients had delayed infectious complications. On the basis of

CIRSE '96 Summary Report

their small series the authors concluded that the use of the Wallstent was not advisable for treatment of benign stenoses. The need for long-term follow-up after treatment of benign biliary strictures was emphasized in a report on 180 patients (Abstract 145). Primary treatment included balloon dilatation followed by catheter stenting, whereas recurrent stenoses were treated with balloon dilatation with subsequent catheter stenting or metallic stent insertion. Long-term patency was assessed by means of life table analysis, including 156 patients who had at least 2 years of follow-up. Primary patency at 10 years was 70% and secondary patency, 75%. The success rate was 82 in Bismuth type I and II strictures and 61% in Bismuth type III or IV strictures. Results of percutaneous management of bile duct injuries due to laparoscopic cholecystectomy in 19 patients were reported (Abstract 143). Thirteen patients had bile duct injuries and presented with jaundice whereas 6 patients had postoperative fluid collections and presented with fever. Following percutaneous drainage procedures and dilatation or stenting of biliary strictures reoperation was avoided in 13 patients, whereas 6 patients still underwent surgery. A combined transhepatic-endoscopic approach to reestablish the continuity of the common bile duct after traumatic injury (n = 1) or surgical transsection (n = 4) was described (Abstract 149). Following placement of a guidewire by means of a "rendez-vous" procedure an internal-external catheter was positioned across the interrupted tract. After immediate elimination of jaundice and bile leakage the catheter remained in place over several months. Long-term follow-up will, however, be required to determine whether surgery can be avoided eventually in these patients.

Interventions in the Gastrointestinal Tract

Wojciech Cwikiel (Lund, Sweden) The use of covered esophageal stents in the palliation of malignant dysphagia has been reported by several authors. A substantial reduction of dysphagia was achieved in the majority of patients treated. Migration of covered stents was the major complication. Twentyone (16%) of 129 inserted covered stents migrated from their initial position (Abstract 67). However, 18 of the migrated stents were initially placed across the gastroesophageal junction; therefore placement of covered stents in this area is questionable. A changed design of the covered stents to ensure better proximal fixation was proposed by the authors during the discussion. Another complication reported in this paper was delayed esophageal hemorrhage, which occurred in 6.6% of patients treated by insertion of esophageal stents. In an-

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other paper (Abstract 72) the same group reported the death of a patient from esophageal hemorrhage after insertion of a covered stent. Fixation of covered stents in the esophagus is achieved by barbs sticking into the mucosa (Gianturco stents) or by sharp wires at the edges of the stent perforating the mucosa (Wallstent). In both these situations vessels in the esophageal wall or in the tumor can be damaged with resultant bleeding. The second of the abovementioned papers pointed out the great value of covered stents in the treatment of patients with esophago-respiratory fistulas; today they are the treatment of choice in this group. The observation time for patients treated with covered stents because of dysphagia is relatively short and the evaluation of long-term results should be valuable. Preliminary results of insertion of the "Esocopha coil," a self-expanding nitinol endoprosthesis which can be retrieved with relative ease, was reported (Abstract 71). This type of stent was also used in the treatment of stenoses of the gastrojejunal anastomosis. Successful treatment of malignant gastroduodenal stenoses by insertion of self-expanding stents was reported in another paper (Abstract 74). While covered stents are valuable in the treatment of patients with dysphagia and esophago-respiratory fistulas, covering of biliary stents with polyurethane does not prevent occlusion of these stents by ingrowth of tumor or granulation tissue (Abstracts 137, 138). An interesting approach to preventing ingrowth of tumor by inhibition of angiogenesis by slow release of Taxol from the coated stent has been presented in an experimental study (Abstract 6). Percutaneous treatment of iatrogenic lesions of the biliary tract has been presented by two different groups with an initial high success rate. The long-term results of percutaneous treatment of patients with benign biliary strictures are also encouraging. Secondary patency rate was 83% and 75% at 5 and 10 years, respectively, in a group of 180 patients (Abstract 135). The value of interventional management in pancreatic disease was the subject of a round-table discussion. Placement of an internal catheter connecting the pancreatic duct to the stomach with the aim of creating a pancreatic "ostium" into the gastric cavity is a new approach (Abstract 212). This procedure was performed in only 1 patient; however, this concept may be interesting to radiologists performing interventions in the gastrointestinal tract. Round Table: Interventional MRI

Rolf W. Giinther (Aachen, Germany) Panelists: G. Adam, S. Heywang-Ktbrunner, K. Kandarpa, W. Mali, G. von Schulthess Each panelist gave a brief overview of the current scientific activities at their own institution. In a state-of-

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the-art lecture preceding the panel discussion, Dr. v. Schulthess presented an overview on interventional MRI applications at Ztirich, where an open magnet has been installed. Dr. Kandarpa from Boston demonstrated the results of a remotely deployable and tunable intravascular radiofrequency coil, which can be introduced through a 9 Fr catheter. The MR images obtained from an in vitro vessel specimen were encouraging and demonstrated the possibility of visualizing vessel wall pathology. Dr. Heywang-K6brunner from Halle described her work on MR-guided breast lesion marking on a conventional high-field system. For guidance, a dedicated coil and localization system is useful; however, at the present time no perfect tool is available, as she stated. She announced a new breast biopsy device, which is still under development, allowing access to lesions close to the chest wall. Dr. Mali from Utrecht demonstrated the results of susceptibility-based catheters for intravascular use in MRI. His group has developed catheters in which the tip is marked with dysprosium spheres causing a susceptibility artifact. This allows good tip visualization using fast gradient echo techniques in flow phantoms and in vivo. Dr. Adam from Aachen demonstrated the feasibility of MR-guided biopsies on a closed 1.5-T system combined with a C-arm fluoroscopy unit. In addition, he presented a field inhomogeneity catheter for intravascular MR-guided procedures, which can be well visualized by MRI using fast gradient echo scans. The following discussion was focused on technical considerations, safety aspects and preliminary indications for MR-guided interventions. All panelists agreed that a high field strength for intravascular imaging is necessary. Moreover, it was pointed out that effective magnet shielding is desirable to enable interventional equipment to be placed close enough to the magnet. Strong gradients and good field homogeneity were also thought to be necessary for interventional MRI. Electrical safety of interventional devices such as catheters, when they are within the main magnetic field during radiofrequency deposition, remains an unsolved problem. As they act like an antenna, they may induce thermal damage in the surrounding tissues. All panelists believed that MRI is already useful for nonvascular interventions such as percutaneous biopsies of the body, breast and brain. It was also concluded that MRI offers the potential of monitoring thermal ablation, and that interventional MRI may become important for endovascular interventions such as dilatation and embolization, as in contrast to X-ray fluoroscopy it offers functional and soft tissue information. Finally, the increased concern with respect to radiation burden in long-lasting fluoroscopy-guided procedures was mentioned as an incentive to develop interventional MRI. Despite promising preliminary results, MRI has a long way to go. Technical problems such as the re-

CIRSE '96 Summary Report

duction of acoustic noise, the development of open systems with the favorable specifications and performance of closed systems, and needle and catheter development were also discussed. Clinically, the development of indications and protocols using the whole functionality of MRI for interventions were addressed as major issues for future research.

Bone Interventions, Pain Therapy, Biopsy and Drainage Luc Stockx (Leuven, Belgium) The results of acrylic vertebroplasty in spinal metastases were discussed, while in another presentation the complications of this technique were described (Abstract 158). Forty-two patients with vertebral metastases were treated with percutaneous vertebroplasty. This recently introduced technique strengthens the vertebral body by filling it with acrylic cement. Indications are vertebral instability and pain. Complete relief of symptoms was obtained in 25 of 42 cases, while partial relief was noted in 7, giving an improvement in 55%. The same technique applied in patients with vertebral hemangioma gave an improvement in respectively 90% and 96%. Complications (10%) were most frequent in metastases and consisted in transient dysphagia due to leakage of the cement. No spinal cord compression was observed. There was neither local recurrence nor tumor progression after 6 months. Surgical ablation remains the treatment of choice for aneurysmal bone cysts, while prior embolization allows better delineation and resection of the tumor with less blood loss (Abstract 157). However, three cases of aneurysmal bone cysts were presented and successfully treated with percutaneous sclerotherapy, using Ethibloc (2 cases) and methylprednisolone acetate mixed with Gelfoam powder. The author advocates this technique as a primary treatment and proposes surgery for resistant cases (Abstract 156). Experience in endovascular particle embolization and chemoembolization in 42 patients with musculoskeletal tumors was presented (Abstract 160). Patients with osteosarcoma were treated with chemoembolization; patients with metastases were treated by embolization of metastases and the primary lesion, sometimes with adjuvant chemotherapy. In benign tumors only embolization was performed. This therapy allowed pain relief and a reduction in tumor size in primary osteosarcoma, making limb salvage surgery possible in 32% of cases. In patients with metastases, treatment controlled pain, while in benign tumors the occlusion allowed less operative blood loss and reduced postoperative complication rates.

CIRSE '96 SummaryReport Results in CT-guided bone and soft-tissue biopsy were presented in 172 patients (Abstract 155). Concerning the histological diagnosis of the lesion, sensitivity and specificity were respectively 76% and 100%, with an accuracy of 78% and a morbidity of 1.2%. The authors stressed that results depend on the cumulative experience of the interventional radiologist and pathologist, and improved with time. In a paper on low-dose chemonucleolysis, intradiscal injection of 2000 units of chymopapain was shown to be successful in 72% of patients with lumbar disc herniation at 6 weeks, comparing favorably with the results of the usual dose used for chemonucleolysis (4000 units) (Abstract 162). The authors also promoted CT-guided peri-radicular infiltration with a combination of local anesthesia and steroids in the treatment of spinal nerve root irritation caused by compression in patients with a narrow neuroforamen due to postoperative fibrosis or disc herniation. Treatment with periradicular or direct intraspinal injection of 40 mg triamcinolone acetonide was performed in 61 patients with low back pain and for sciatalgia (Abstract 163). After treatment, improvement of the symptoms was achieved in 78% of patients, while at mid-term follow-up (mean 6 months) 66% of the patients presented with continuous improvement. There were no procedure-related complications. During a scientific session on biopsy and drainage, the histopathological correlation of ultrasoundguided fine needle aspiration cytology in breast lesions was presented (Abstract 207). Using a 21gauge 8 cm long needle, ultrasound-guided aspiration cytology was performed in 126 patients. True positive cytology was achieved in 86% of benign lesions and in 70.6% of malignant lesions; 7% were false positive and 11% false negative. Inconclusive cytology was found in 14% of cases. These results suggest that this technique should be used to corre-

247 late with the radiologically expected nature of the lesion and not to rule out malignancy. Using the quick-core needle in transjugular liver biopsy, a technical success rate of 97% was achieved, with a mean specimen size of 1.5 cm (Abstract 208). Diagnosis was possible in 97% of cases (108/111); the complication rate was 2.6%. These results are superior to those obtained with other biopsy systems. In a prospective randomized trial it was shown that the use of spiral CT neither improves the results nor reduces the complication rate of percutaneous transthoracic needle biopsy compared with sequential CT, and that procedure time is not decreased (Abstract 209). A laser for CT control of percutaneous intervention was shown (Abstract 210). Phantom tests showed an increase in accuracy of the puncture, which was highly significant in the case of oblique access with the gantry tilted. These results were confirmed in patients. Using a coaxial access technique for percutaneous biopsy in various lesions, based on a stylet used as a guide through an initially introduced 22 G needle and advanced toward the target, it appeared that this is a safe and effective method for biopsy sites where access is difficult (Abstract 211). The technique and results of percutaneous insertion of an internal drainage catheter for peripancreatic fluid collections in 13 patients were demonstrated on video in one paper. The effectiveness as well as the safety of this procedure was confirmed in a group of 10 patients (Abstract 213). In an animal study, Gd-DTPA was proven to be an effective contrast material in 90% ethanol (Abstract 215). The injection of the ethanol solution resulted in almost instantaneous precipitation of the tissue, which inhibited the washout of the co-administered Gd-DTPA and thus visualized the treated tissue volume. The demarcation of the necrotized tissue remained stable for at least 30 min. The data look promising for clinical use in tumor therapy.