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Scientific Session 11 Oncology: Bone/Lung/Prostate Ablation Saturday, March 3, 2007 1:30 PM - 3:30 PM Room: 205 1:30 PM Abstract No. 96 FEATURED ABSTRACT Radiofrequency Ablation of Osteoid Osteomas: Techni- cal, Clinical and Imaging Outcomes. E.B. Hayeems, University Health Network and Mount Sinai Hospital, Toronto, ON, Canada J.R. Kachura PURPOSE: To report our experience with radiofrequency ablation of osteoid osteomas. MATERIALS AND METHODS: From September 2004 to July 2006, 27 CT-guided radiofrequency ablation (RFA) procedures were performed on 26 patients (19M/7F) with symptomatic osteoid osteomas. Mean age was 29 years (17-62). 23 patients had lower extremity or pelvic lesions, and 3 had upper extremity or scapular lesions. 15 patients underwent general anesthesia, 3 had general anesthesia combined with a nerve block and 8 had epidural anesthesia during their ablation procedures. 4 different types of probes and generators were used in this experience. Clinical and imaging follow-up time ranged from 1 day to 1 year. Fol- low-up imaging was performed with gadolinium-enhanced MR imaging at one month post procedure. RESULTS: 100% (27/27) of the procedures were technically successful with CT evidence of the ablation probe centered within the nidus of the lesion. 4 patients were lost to clinical or imaging follow-up. No periprocedural or post procedure complications were noted in the remaining patients. 86% (19/22) of patients had clinical resolution of their pain post procedure. 3 patients (14%) had no significant reduction in their pain post procedure. One of these patients elected to have a repeat RFA of her osteoid osteoma which resulted in immediate resolution of pain as well as no recurrence of symptoms at 6 months post procedure. In 88% (7/8) of patients who underwent gadolinium enhanced MR imaging at 1 month post procedure there was no evidence of en- hancement of the nidus. All of these patients were symptom free at the time of their follow-up imaging. The patient who underwent a repeat procedure had evidence of enhancement of the nidus on the gadolinium-enhanced MR images fol- lowing her first ablation procedure. CONCLUSION: RFA is a safe and effective treatment for osteoid osteomas. Follow-up imaging with gadolinium-en- hanced MR imaging is a good predictor of symptomatic relief post ablation. 1:45 PM Abstract No. 97 Radiofrequency Ablation for the Treatment of Bone Metastasis Adjacent to Nerve under Temperature Mon- itoring. A. Nakatsuka, Mie Univ. School of Med., Tsu, Edobashi, Mie Pref., Japan K. Yamakado H. Takaki J. Uraki K. Takeda PURPOSE: Radiofrequency (RF) has proved to be a useful treatment in patients with bone metastasis. However, the risk of neural damage limits the use of RF ablation. This prospective study was undertaken to assess the feasibility, effectiveness and safety of RF ablation under real-time temperature monitoring for the treatment of bone metastases adjacent to nerves. MATERIALS AND METHODS: Thirteen patients with 14 bone metastases adjacent to nerves received RF ablation. Tumor location was vertebral body or pedicle in 12 lesions, iliac bone in one patient, and femoral bone in one patient. The max. tumor diameter ranged from 1 cm to 8 cm (mean 4.6 cm). Distance between bone metastasis and nerve ranged from 0.1 to 1.7 cm (mean 0.4 cm). All procedures were done under real-time CT fluoroscopic guidance. After the internally cooled-tip RF electrode was placed in the tumor, the thermocouple was placed between the tumor and the nerve (extradural or intradural space). Then, RF energy was applied for 5 minutes under real-time temperature mon- itoring. When temperature around the nerve rose up to 45°C, RF ablation was immediately stopped. Pain relief was evaluated in 8 patients with painful lesions using the visual analogue scale (VAS) score (0-10). Local therapeutic ef- fects were evaluated on contrast-enhanced MR imaging. Free of tumor enhancement was considered to be necrosis. RESULTS: Temperature around the nerves did not rise up to 45°C and RF ablation was done for 5 minutes in 11 lesions (79%). In the other 3 lesions, temperature around the nerve rose up to 45°C and RF ablation was stopped 3-5 minutes (mean, 3.7 minutes) after the initiation. Transient neural damage that resolved in 2 days occurred in one of 3 patients in whom temperature around the nerve rose up to 45°C. Pain was relieved within a week in all 8 patients who had experienced pain. The mean VAS scores were significantly decreased from 7.5 2.7 to 2.7 2 (P 0.01). Contrast- enhanced MR imaging showed the mean tumor necrosis rates was 71 29% (range; 22%-100%). CONCLUSION: The technique presented here appears to be a practical, safe, and effective technique for preventing severe nerve injury in thermal ablation therapy in patients with bone neoplasms adjacent to nerves. 1:57 PM Abstract No. 98 [R/F] Radiofrequency Ablation of Bone with Cooled Probes and Impedance Control Energy Delivery in a Pig Model. C.P. Cantwell, Mater Misericordiae University Hospital, Dublin, Ireland R. Flavin K. Sheehan R. Deane P. Dervan J. O’Byrne, et al. PURPOSE: Determine the coronal marrow ablation length and detect cortical bone effects after radiofrequency abla- tion of bone in a pig model. MATERIALS AND METHODS: 12 pigs underwent radio- frequency ablation with a 1 or 2 cm cooled probe of the mid diaphyseal point of their long bones at one, seven or 28 days before euthanasia. 12 minutes of impedance control radio- frequency energy was delivered at maximum output from a 200 W generator. Pigs were imaged with axial and coronal (TSE) T1 and T2 weighted frequency selective fat suppres- sion (SPIR). A radiologist blinded to the timing of the treatment and the results of other imaging sequences mea- sured the coronal ablation zone length and cortical thick- ness. RESULTS: On SPIR the zone of marrow ablation was low signal surrounded by a high signal band. On T1 the zone of Scientific Sessions SATURDAY S37

Oncology: Bone/lung/prostate ablation

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Scientific Session 11

Oncology: Bone/Lung/ProstateAblation

Saturday, March 3, 20071:30 PM - 3:30 PMRoom: 2051:30 PM Abstract No. 96FEATURED ABSTRACTRadiofrequency Ablation of Osteoid Osteomas: Techni-cal, Clinical and Imaging Outcomes.E.B. Hayeems, University Health Network and Mount SinaiHospital, Toronto, ON, Canada � J.R. Kachura

PURPOSE: To report our experience with radiofrequencyablation of osteoid osteomas.

MATERIALS AND METHODS: From September 2004 toJuly 2006, 27 CT-guided radiofrequency ablation (RFA)procedures were performed on 26 patients (19M/7F) withsymptomatic osteoid osteomas. Mean age was 29 years(17-62). 23 patients had lower extremity or pelvic lesions,and 3 had upper extremity or scapular lesions. 15 patientsunderwent general anesthesia, 3 had general anesthesiacombined with a nerve block and 8 had epidural anesthesiaduring their ablation procedures. 4 different types of probesand generators were used in this experience. Clinical andimaging follow-up time ranged from 1 day to 1 year. Fol-low-up imaging was performed with gadolinium-enhancedMR imaging at one month post procedure.

RESULTS: 100% (27/27) of the procedures were technicallysuccessful with CT evidence of the ablation probe centeredwithin the nidus of the lesion. 4 patients were lost to clinicalor imaging follow-up. No periprocedural or post procedurecomplications were noted in the remaining patients. 86%(19/22) of patients had clinical resolution of their pain postprocedure. 3 patients (14%) had no significant reduction intheir pain post procedure. One of these patients elected tohave a repeat RFA of her osteoid osteoma which resulted inimmediate resolution of pain as well as no recurrence ofsymptoms at 6 months post procedure. In 88% (7/8) ofpatients who underwent gadolinium enhanced MR imagingat 1 month post procedure there was no evidence of en-hancement of the nidus. All of these patients were symptomfree at the time of their follow-up imaging. The patient whounderwent a repeat procedure had evidence of enhancementof the nidus on the gadolinium-enhanced MR images fol-lowing her first ablation procedure.

CONCLUSION: RFA is a safe and effective treatment forosteoid osteomas. Follow-up imaging with gadolinium-en-hanced MR imaging is a good predictor of symptomaticrelief post ablation.

1:45 PM Abstract No. 97

Radiofrequency Ablation for the Treatment of BoneMetastasis Adjacent to Nerve under Temperature Mon-itoring.A. Nakatsuka, Mie Univ. School of Med., Tsu, Edobashi,Mie Pref., Japan � K. Yamakado � H. Takaki � J. Uraki � K.Takeda

PURPOSE: Radiofrequency (RF) has proved to be a usefultreatment in patients with bone metastasis. However, therisk of neural damage limits the use of RF ablation. Thisprospective study was undertaken to assess the feasibility,effectiveness and safety of RF ablation under real-timetemperature monitoring for the treatment of bone metastasesadjacent to nerves.

MATERIALS AND METHODS: Thirteen patients with 14bone metastases adjacent to nerves received RF ablation.Tumor location was vertebral body or pedicle in 12 lesions,iliac bone in one patient, and femoral bone in one patient.The max. tumor diameter ranged from 1 cm to 8 cm (mean4.6 cm). Distance between bone metastasis and nerveranged from 0.1 to 1.7 cm (mean 0.4 cm). All procedureswere done under real-time CT fluoroscopic guidance. Afterthe internally cooled-tip RF electrode was placed in thetumor, the thermocouple was placed between the tumor andthe nerve (extradural or intradural space). Then, RF energywas applied for 5 minutes under real-time temperature mon-itoring. When temperature around the nerve rose up to45°C, RF ablation was immediately stopped. Pain relief wasevaluated in 8 patients with painful lesions using the visualanalogue scale (VAS) score (0-10). Local therapeutic ef-fects were evaluated on contrast-enhanced MR imaging.Free of tumor enhancement was considered to be necrosis.

RESULTS: Temperature around the nerves did not rise up to45°C and RF ablation was done for 5 minutes in 11 lesions(79%). In the other 3 lesions, temperature around the nerverose up to 45°C and RF ablation was stopped 3-5 minutes(mean, 3.7 minutes) after the initiation. Transient neuraldamage that resolved in 2 days occurred in one of 3 patientsin whom temperature around the nerve rose up to 45°C.Pain was relieved within a week in all 8 patients who hadexperienced pain. The mean VAS scores were significantlydecreased from 7.5 � 2.7 to 2.7 � 2 (P � 0.01). Contrast-enhanced MR imaging showed the mean tumor necrosisrates was 71 � 29% (range; 22%-100%).

CONCLUSION: The technique presented here appears to bea practical, safe, and effective technique for preventingsevere nerve injury in thermal ablation therapy in patientswith bone neoplasms adjacent to nerves.

1:57 PM Abstract No. 98[R/F]Radiofrequency Ablation of Bone with Cooled Probesand Impedance Control Energy Delivery in a Pig Model.C.P. Cantwell, Mater Misericordiae University Hospital,Dublin, Ireland � R. Flavin � K. Sheehan � R. Deane � P.Dervan � J. O’Byrne, et al.

PURPOSE: Determine the coronal marrow ablation lengthand detect cortical bone effects after radiofrequency abla-tion of bone in a pig model.

MATERIALS AND METHODS: 12 pigs underwent radio-frequency ablation with a 1 or 2 cm cooled probe of the middiaphyseal point of their long bones at one, seven or 28 daysbefore euthanasia. 12 minutes of impedance control radio-frequency energy was delivered at maximum output from a200 W generator. Pigs were imaged with axial and coronal(TSE) T1 and T2 weighted frequency selective fat suppres-sion (SPIR). A radiologist blinded to the timing of thetreatment and the results of other imaging sequences mea-sured the coronal ablation zone length and cortical thick-ness.

RESULTS: On SPIR the zone of marrow ablation was lowsignal surrounded by a high signal band. On T1 the zone of

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marrow ablation was heterogeneously isointense sur-rounded by a low signal band. The mean (� standarddeviation) coronal measure of the marrow zone of ablationon SPIR imaging at 28 days with a 1 and 2 cm probe was47.1 � 8.6 mm and 51.3 � 6.5 mm, respectively. 2 humeralfractures were experienced at 21 and 28 days after therapy.Thinning of the cortex adjacent to the probe insertion sitewas identified in the humeral group only.

CONCLUSION: The coronal measurement of the marrowsignal change with a 2 cm probe and this energy deliveryprotocol is larger than that with a 1 cm probe. The marrowsignal change with this energy delivery protocol is largerthan the reported data for temperature controlled protocols.Radiofrequency ablation leads to significant cortical thin-ning at the site of probe insertion and bone weakening if a2 cm probe is used in the humerus of pigs.

2:09 PM Abstract No. 99

Complication Following Lung Radio-Frequency (RF)Ablation: Relationship with Radiotherapy.M. Nomura, Mie University Hospital, 2-174 Edobashi, Tsu,Mie, Japan � K. Yamakado � Y. Nomoto � A. Nakatsuka � H.Takaki � K. Takeda

PURPOSE: Lung cancer is the commonest cause of cancerdeath in both sexes worldwide with most often advancedand incurable disease at time of diagnosis. And lung is acommon site of metastases for various malignancies butsurgery for lung metastases is accepted in selected patients.Chemotherapy or radiotherapy or both have been done forinoperable lung neoplasm, but it has not satisfactorily af-fected the outcome. Recently lung RFA attracts attention asa relatively safe, effective and repeatable treatment option.The purpose of this study is to investigate major complica-tions of lung radio-frequency (RF) ablation in patients withprimary or secondary lung tumor, especially the relationshipwith radiotherapy.

MATERIALS AND METHODS: Lung RF ablation was donein 132 patients with 324 sessions from January 2002 toMarch 2006. Sixteen patients (12%) had primary lung can-cer and 116 patients (88%) had lung metastases. Twentypatients had undergone lung resection, 15 radiotherapy, and3 both before RF ablation. Incidence of mortality and majorcomplications that required treatments were reported. TheC-reactive protein (CRP) levels were evaluated whetherprevious treatments have relationships with severe lunginflammation after RF ablation.

RESULTS: Fatal interstitial pneumonia developed in 2 pa-tients (0.6%). Both patients had undergone lung resectionand radiotherapy before RF ablation. Major complicationsincluded 109 sessions (34%). Chest tubes were placed dueto pneumothorax in 38 sessions (12%), due to pleuritis in 12sessions (3.7%), due to empyema in 2 sessions (0.6%).Chest wall tumor dissemination was found in 1 session(0.3%). The mean CRP level was significantly higher inpatents who had received radiotherapy (average 12.0 mg/dL) than those with lung resection (average 3.9 mg/dL) andthose with no previous treatments (average 3.3 mg/dL).

CONCLUSION: Lung RF ablation is a relatively safe pro-cedure. Combination of radiotherapy and RF ablation can bea risk factor for severe inflammation in the lung. There area lot of matters that have yet to be made clear, but we cansay that attention should be paid to indicate lung RF abla-tion in patients who have received radiotherapy before.

2:21 PM Abstract No. 100

Long-Term Follow-up after Percutaneous PulmonaryRadiofrequency Ablation.M.A. Rehim, Institut Gustave Roussy, Villejuif, Val DeMarne, France � J. Palussiere � A. Auperin � L. Hechelham-mer � J. Cazojust � T. De Baere

PURPOSE: To evaluate the long-term survival and outcomeafter radiofrequency ablation (RFA) of lung tumors.

MATERIALS AND METHODS: 89 patients (55% male)aged 27-85 years (mean � 62) with 134 lung tumors (16primaries, 118 metastases) were treated with CT-guidedRFA using expandable needles between January 2002 andAugust 2006 in two French centers. RFA was evaluated byCT at 2, 4, 6 and then every three months.

RESULTS: RFA was technically possible in all but onepatient. After 99 sessions of RFA, incidental image findingswere 37 pneumothoraces, 13 alveolar hemorrhages whichdid not need treatment. Complications were 8 pneumotho-races requiring drainage, 4 pneumonias, 2 septicemias, oneskin burn and one pseudo-membranous colitis. After medianfollow-up of 2 years (6 months -4 years), the estimatedsurvival rate at 2 years was 70%. The rate of incompletelocal treatment (ILT) was 8%/13% per tumor, 11%/21% perpatient at one/two years, respectively. ILT rate at 2 years forthe 95 tumors less than 2 cm was 9%. ILT rate for the 39tumors more than 2 cm was 25%. ILT rate was statisticallysignificant between the two groups (log rank test p �0.057).

CONCLUSION: Pulmonary RFA shows promising long-term success rates for local control, and two-year survivalclose to what is reported in surgical series. Tumor size lessthan 2 cm in diameter has a lower rate of local recurrence.

2:33 PM Abstract No. 101

The Study about the Factor of Local Recurrence afterRF Ablation for Small Lung Malignancies.T. Matsuoka, Osaka City University, Graduate School ofMedicine, Osaka, Japan � M. Toyoshima � T. Okuma � A.Yamamoto � Y. Oyama � K. Nakamura, et al.

PURPOSE: Radiofrequency (RF) ablation is considered asradical treatment of small lung malignancies. This studyinvestigates the factors of local recurrence after RF ablationfor primary and metastatic lung malignancies smaller than 3cm in diameter.

MATERIALS AND METHODS: 52 nodules (5-29 mm,mean 17.3 mm, primary 16, metastases 36) in 29 patientswere treated by RF ablation under CT guidance usingLeVeen needle 2 or 3 cm in diameter and were observedmore than six months after the procedure from June 2000 toSeptember 2006. The procedure was started at 10-30 wattsby gradually increasing output until roll off (sudden rise ofimpedance meaning tissue coagulation) was achieved. Themaximum power was kept under 80 watts and the procedurewas canceled when roll off was not completed even if itpassed for 30 minutes. The entire tumor was ablated usingan overlapping technique with aiming 5 mm of safety mar-gin. CT was performed every 2 or 3 months after theprocedure and the largest diameter (LD) of ablated areaconsisting of the lesion and surrounding lung tissue wasmeasured. It was judged as a recurrence when LD whichhad reduced with time turned in increase.

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RESULTS: In 43 nodules, roll off was achieved in allablated areas and in 9 nodules, roll off was not achieved ina part of the nodule. The causes why roll off was notachieved were severe pain in five patients, cough in one andunknown in three. The mean follow-up periods were 16.6months (6-48 months). Local tumor progression was ob-served in 14 of 52 patients. Recurrence was detected at lessthan 6 months in 4 nodules, 6-9 months in 5, 9-12 monthsin 3 and more than 12 months in 2. Local tumor control wasobtained in 73% of patients. The group in which roll off wasachieved in the whole lesion had a significantly higher localcontrol rate of 83.7% (36/43) than non roll off group of22.2% (2/9). In 7 nodules, recurrence occurred although rolloff was achieved in all of the ablated area. Inadequate safetymargin was thought as a cause of recurrence in 5 nodulesand causes were unknown in 2 nodules.

CONCLUSION: To improve the local control rate, it isimportant to achieve roll off in all of the nodule with anadequate safety margin.

2:45 PM Abstract No. 102

The “Male Lumpectomy”: Focal Therapy for ProstateCancer Using Cryoablation Results in 112 Patients.G. Onik, Celebration Health/Florida Hospital, Celebra-tion, FL, USA

PURPOSE: The use of “lumpectomy” has revolutionizedmanagement of breast cancer. Lumpectomy showed thatquality of life issues can successfully be addressed withoutcompromising treatment efficacy. Traditional thinking heldthat prostate cancer was multifocal and therefore not ame-nable to a similar focal treatment approach. Pathologicliterature, however, indicates that up to 70% of PCa patientsmight be successfully treated with a limited “lumpectomy”.In this paper we report the results of focal therapy forprostate cancer using cryoablation.

MATERIALS AND METHODS: Staging biopsies were car-ried out using a brachytherapy grid under US guidance.Biopsy samples of the prostate were obtained every 5 mil-limeters throughout its volume and the location of eachbiopsy recorded. Cryoablation using the usual methods wascarried out to encompass just the known area of tumor basedon the mapping biopsies. Postoperatively, PSA levels wereobtained every 3 months for two years and then every 6months thereafter. The first 26 patients with stable PSAlevels routinely underwent biopsy at one year.

RESULTS: Between 6/95 and 8/06, 112 patients had focalcryoablation. 55 patients have at least 1 year follow-up. Ofthese 55 patients, follow-up ranged from 1 year- 11 yearswith a mean of 3.6 years. 52 of 55 patients (95%) havestable PSAs (ASTRO criteria) with no evidence for cancer,despite 29 patients being medium to high risk for recur-rence. Of the 26 patients with stable PSAs who underwentroutine biopsies, all were negative. No local recurrenceswere noted in areas treated. Potency was maintained in 44 of51 patients (86%) who were potent prior to cryoablation. Of111 patients without previous prostate surgery or radiationtherapy, all were continent.

CONCLUSION: These preliminary results indicate a “malelumpectomy” in which only the prostate tumor region itselfis destroyed, appears to preserve potency in a majority ofpatients and limits other complications (particularly incon-tinence), without compromising cancer control. These re-sults show this approach could have a profound effect on

prostate cancer management and therefore warrants furtherlarge-scale controlled trials.

2:57 PM Abstract No. 103

Percutaneous Ultrasound-guided Ablation of ProstateUsing Irreversible Electroporation (IRE).G. Onik, Celebration Health/Florida Hospital, Celebra-tion, FL, USA � P. Mikus � B. Rubinsky

PURPOSE: Ablation of prostate cancer using cryotherapy isefficacious treatment for primary prostate cancer. With itsapproval by Medicare reimbursement in June 2000, it tookits place beside radiation and radical prostatectomy as anon-investigational procedure. The use of thermal energy(cryo, RF, Laser, microwave) to ablate prostate tissue hasinherent qualities that limits its clinical usefulness, however.For instance, tumors adjacent to vessels can recur due to thevessel heat sink effect. Additional limitations, such as theextremely slow resolution of treated lesions and the collat-eral destruction of nearby structures such as the urethra andrectum, limit the applications of thermal tumor ablation.Irreversible Electroporation (IRE) consists of applying mi-crosecond pulses of direct current to create holes in the cellmembrane. Due to the short duration of the pulses, thermalchanges are not encountered and blood flow has no effect.The preliminary animal results presented in this paper willhighlight the potential advantages of such an approach toprostate tissue destruction.

MATERIALS AND METHODS: IRE was performed using18-gauge stainless steel electrodes on 3 male dogs. Abla-tions were carried out in the prostate using TRUS monitor-ing. The pulses was delivered transperineally using a DCgenerator (Oncobionic Inc.) in a bipolar manner betweentwo electrodes at 1 kV and in one animal a single bipolarelectrode was delivered transrectally. Animals were sacri-ficed at 24 hours and the prostate was examined usingstandard H and E staining.

RESULTS: All animals survived the procedure. IRE lesionscreated were approximately 1 cm in diameter. Unique char-acteristics of IRE lesions demonstrated on pathology in-cluded: 1) uniform destruction to the margin of the lesion. 2)discrete zone of transition from normal to ablated tissue 3)complete ablation adjacent to vessels. 4) No evidence fordestruction of the collagenous structures such as urethra.

CONCLUSION: IRE represent a non-thermal ablation mo-dality which may have distinct advantages in the prostate. Itcan be delivered transrectally and creates a very distinctzone of destruction making it an ideal platform for focaldestruction of prostate cancer.

3:09 PM Abstract No. 104

Paravertebral Block Anesthesia When Performing Ra-diofrequency Ablation.M.L. Montgomery, Texas A&M College of Medicine, Tem-ple, TX, � W.C. Culp � C.D. Brooks � M.N. Payne � P.A. Neese� D.K. McDonald

PURPOSE: Adequate pain control when performing radio-frequency ablation (RFA) can be a challenge to the inter-ventional radiologist. The purpose of this study is to eval-uate the usefulness of adding a paravertebral block to theconscious sedation medication regimen before RFA. Thisstudy will also review a single center’s techniques andstrategies for performing conscious sedation during RFA forabdominal malignancies.

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MATERIALS AND METHODS: 42 procedures treated withRFA over 1.5 years involving kidney, liver and adrenalmalignancies were assessed. Dosages of sedatives in proce-dures with and without paravertebral blocks were compared.Pain thresholds were assessed. Performance of paravertebralblocks was further subdivided into those performed with theanesthesiologist using nerve stimulation guidance and thoseby the interventional radiologist using image guidance.

RESULTS: 25 procedures were performed without paraver-tebral blocks and 17 with paravertebral blocks. The averagedose of midazolam and fentanyl per procedure without ablock was 5.4 mg and 265 mcg, respectively. The averagedose of midazolam and fentanyl with a paravertebral blockwas 4.1 mg and 201 mcg, respectively. 4 paravertebralblocks were performed by the anesthesiologist using nervestimulation guidance. Of those performed by the anesthesi-ologist, the average dose of midazolam and fentanyl was 3.7mg and 125 mcg. In 15 of 25 (60%) procedures performedwithout a block, patient’s procedural pain was well con-trolled with conscious sedation alone. In 13 of 17 (76%)procedures, patients reported no significant pain when aparavertebral block was utilized. 100% of patients who hadnerve stimulation guidance for needle placement by theanesthesiologist stated they received adequate pain control.

CONCLUSION: The addition of a paravertebral block be-fore performing RFA with conscious sedation resulted in anincrease patient satisfaction rate as well as a slight decreasein the dosage of medication needed during RFA. Blocksperformed by the anesthesiologist using nerve stimulationtechniques were helpful in all cases. Paravertebral blocksproved to be a useful technique and should be consideredbefore performing radiofrequency ablation.

3:21 PM Abstract No. 105

RF Ablation for the Treatment of Both Lung and LiverMetastasis from Colorectal Carcinoma: A ProspectiveStudy.H. Takaki, Mie University School of Medicene, Tsu, Mie,Japan � K. Yamakado � A. Nakatsuka � K. Takeda

PURPOSE: This study was prospectively undertaken toevaluate the clinical utility of radiofrequency (RF) ablationin patients with colorectal cancer who had both lung andliver metastasis.

MATERIALS AND METHODS: Seven patients who met thefollowing criterion were included in this study: 1) completeresection of primary lesions, 2) metachronous lung and livermetastasis or synchronous metastasis treated by RF abla-tion, 3) maximum tumor size of 3 cm with a tumor numberof 5 or less in each organ, 4) no metastasis other than lungand liver. There were 12 liver metastases and 13 metastasesat the time of RF ablation. The mean tumor size was 1.9 �0.6 cm. RF ablation was done under the CT fluoroscopicguide. Appearance of low or high density covering livermetastasis and ground-glass opacity covering lung metasta-sis on CT images acquired immediately after RF ablationwas considered to be technical success. Technical effective-ness was defined as absence of tumor enhancement of livermetastasis on contrast-enhanced CT obtained 1 week afterliver RF ablation and absence of FDG accumulation in thelung metastasis on FDG-PET study 3 months after lung RFablation.

RESULTS: Interval between the first RF ablation and thelast RF ablation ranged from 0-40 months (mean, 17months). Technical successful was achieved in all patients

(7/7, 100%). Technical effectiveness was also achievedafter 16 RF sessions in all patients. Local tumor progressionwas not found during the mean follow-up period of 30months (range: 18-49 months). However, new tumors ap-peared in the lung (n � 2), liver (n � 2), and lymph node(n � 2) in 4 patients (4/7, 57%) and 1 patient died of tumorprogression. The median survival time and the 4-year sur-vival rate were 28 months and 100% after the initial RFablation, and 12 months and 100% after the last RF ablation.

CONCLUSION: This study shows that RF ablation can be auseful therapeutic option in patients with colorectal cancerwho have both lung and liver metastasis.

Scientific Session 12Room: 210Arterial Interventions: Peripheral

Saturday, March 3, 20071:30 PM - 3:30 PM

1:30 PM Abstract No. 106

Percutaneous Reconstruction of the Aortic Bifurcationwith Nitinol Stents: Short and Mid-Term Results.I.K. Tesdal, Klinikum Friedrichshafen, Friedrichshafen,Baden Wurtemberg, Germany � M. Wikstrom � P. Vogel

PURPOSE: A prospective study of feasibility and efficacyof stent angioplasty at the aortic bifurcation using nitinolstents.

MATERIALS AND METHODS: From October 2000 to De-cember 2005, 49 consecutive patients underwent primarystent placement at the aortic bifurcation. The main indica-tion was intermittent claudication (n � 45). According toSCVIR (now SIR) classification 19 patients had grade 4, 17grade III, and 13 grade II lesions. After predilation weplaced 99 self-expanding nitinol stents (Symphony stent),and 5 balloon-expandable stents. All patients were fol-lowed-up by physical examination and Doppler sonography(range, 6-58 months). Estimates for the cumulative patency,survival and restenosis rates were calculated by using lifetable analysis.

RESULTS: Forty-eight of 49 patients had successful stentplacement. Residual stenosis was seen in 5 patients, and wastreated by combining self-expanding and balloon-expand-able stents. Complications were seen in 3 patients, and onepatient required surgery (hematoma). Restenosis occurred infour patients. The primary patency rates after 6, 12, 24 and48 months were 96%, 96%, 92% and 82%, respectively.

CONCLUSION: Primary placement of nitinol stents inchronic stenoses and occlusions of the aortic bifurcationgives high immediate and mid-term success rates. Due toextensive calcified lesions a combination with balloon-ex-pandable stents is necessary in about 10% of patients.

1:42 PM Abstract No. 107

Viabahn-Assisted Subintimal Recanalization (VASIR)of Superficial Femoral Artery Occlusions.M.J. Verta, Endovascular Center, Evanston NorthwesternHealthcare, Evanston, IL, USA � J.R. Schneider � M. Alonzo� D. Hahn

PURPOSE: To evaluate VASIR in long recanalizations ofthe superficial femoral artery (SFA).

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