Complications associated with the percutaneous insertion of fiducial markers in the thorax

Purpose

Radiosurgery requires precise lesion localization. Fiducial markers enable lesion tracking, but complications from insertion may occur. The purpose of this study was to describe complications of fiducial marker insertion into pulmonary lesions.

Materials and Methods

Clinical and imaging records of 28 consecutive patients with 32 lung nodules or masses who underwent insertion of a total of 59 fiducial markers before radiosurgery were retrospectively reviewed.

Results

Eighteen patients (67%) developed a pneumothorax, and six patients (22%) required a chest tube. The rates of pneumothorax were 82% and 40%, respectively, when 18-gauge and 19-gauge needles were used for marker insertion (P = 0.01). Increased rate of pneumothorax was also associated with targeting smaller lesions (P = 0.03) and tumors not in contact with the pleural surface (P = 0.04). A total of 11 fiducials (19%) migrated after insertion into the pleural space (10 markers) or into the airway (1 marker). Migration was associated with shorter distances from pleura to the marker deposition site (P = 0.04) and with fiducial placement outside of the target lesion (P = 0.03).

Conclusion

Fiducial marker placement into lung lesions is associated with a high risk of pneumothorax and a risk of fiducial migration.

Effect of advanced imaging technology on how biopsies are done and who does them

PURPOSE

To assess national levels and trends in utilization of biopsy procedures during the past decade and investigate the relative roles of biopsy approaches (open, endoscopic, and percutaneous) and physician specialties.

MATERIALS AND METHODS

Institutional review board approval was not necessary because only public domain data were used. Aggregated Medicare claims data were used to determine utilization of biopsies performed in 10 anatomic regions from 1997 to 2008. Utilization levels according to biopsy approach and anatomic region were calculated. Trends in the relative utilization of percutaneous needle biopsy (PNB) and imaging-guided percutaneous biopsy (IGPB) were assessed. The relative roles of radiologists and nonradiologists in the performance of all biopsies, PNBs, and IGPBs were evaluated.

RESULTS

Biopsy procedures with all approaches increased from 1380 to 1945 biopsies per 100,000 Medicare enrollees between 1997 and 2008, which represents a compound annual growth rate (CAGR) of 3%. Utilization of non-PNBs fell, while the absolute level and relative share of PNBs increased. In 2008, 67% of all biopsies were performed by using a percutaneous route. IGPB as a percentage of all PNBs increased over time in the regions for which data were available. Radiology was the leading specialty providing biopsy services. The total number of biopsies performed by radiologists increased at a CAGR of 8%, and radiologists' share of all biopsies increased from 35% to 56%.

CONCLUSION

During the past decade, there was continuing substitution away from invasive approaches and non-imaging-guided percutaneous approaches in favor of PNBs and IGPBs, likely related to increasing use of advanced imaging modalities for biopsy guidance. Consequently, radiologists are performing an increasing share of biopsies across all anatomic regions.

Utilization of interventional oncology treatments in the United States

PURPOSE

To report on the recent national trends in utilization of interventional oncology (IO) treatments, assess the use of these techniques relative to the utilization of alternative oncologic treatments, and provide an assessment of which specialties are providing these services.

MATERIALS AND METHODS

The Centers for Medicare and Medicaid Services Physicians/Supplier Procedure Summary Master Files from 2002 through 2008 and Limited Data Set Standard Analytical Files from 2002 through 2007 were used to determine utilization rates of ablative therapies and transarterial embolizations for malignant neoplasms and comparable surgical procedures.

RESULTS

In 2008, 10,045 IO treatments were performed in the Medicare population, or 29 per 100,000 Medicare enrollees. IO treatments of the liver constituted the largest component, at 64%, followed by the kidneys at 23%. Over a period of 6 years, growth was seen in all IO procedures except for transarterial embolizations for renal tumors. Radiologists performed 91% of all IO procedures in 2008.

CONCLUSIONS

IO utilization is modest in volume, but growing. IO treatments comprised the majority of oncologic treatments in the liver but only a small part of treatments in the kidneys and lungs. Radiologists are currently providing the vast majority of IO treatments.

Rates and predictors of plans for inferior vena cava filter retrieval in hospitalized patients

BACKGROUND

Use of inferior vena cava (IVC) filters has been increasing over time. However, because of the increased risk of deep vein thrombosis with permanent filters, placement of retrievable filters has been recommended. Little is known about the factors associated with planned retrieval of IVC filters.

OBJECTIVE

To describe rates and predictors of plans to retrieve IVC filters in hospitalized patients.

DESIGN

We identified all IVC filter placements from 2001-2006 at an academic medical center and reviewed medical charts to obtain data about patient characteristics, filter retrieval plans, and retrieval success rates. Multivariable logistic regression was used to identify independent predictors of planned filter retrieval in patients with retrievable filters.

RESULTS

Out of 240 patients who underwent placement of retrievable IVC filters, only 73 (30.4%) had documented plans for filter retrieval. Factors associated with lower rates of planned filter retrieval included a history of cancer [adjusted odds ratio (OR) and 95% confidence interval 0.2 (0.1-0.5)] and not being discharged on anticoagulants [OR 0.1 (0.1-0.3)]. In addition, 36 (21.6%) of patients without retrieval plans had no contraindications to retrieval. Of the 62 patients who underwent attempted filter retrieval, 25.8% of filters could not be successfully removed.

CONCLUSIONS

Only 30.4% of patients who underwent placement of a retrievable IVC filter had documented plans for filter removal. Although most patients had justifiable reasons for filter retention, 21.6% of patients had no clear contraindications to filter removal. Efforts to improve rates of filter retrieval in appropriate patients may help reduce the long-term complications of IVC filters.

Excellent outcome following down-staging of hepatocellular carcinoma prior to liver transplantation: an intention-to-treat analysis

We previously reported encouraging results of down-staging of hepatocellular carcinoma (HCC) to meet conventional T2 criteria (one lesion 2-5 cm or two to three lesions <3 cm) for orthotopic liver transplantation (OLT) in 30 patients as a test of concept. In this ongoing prospective study, we analyzed longer-term outcome data on HCC down-staging in a larger cohort of 61 patients with tumor stage exceeding T2 criteria who were enrolled between June 2002 and January 2007. Eligibility criteria for down-staging included: (1) one lesion >5 cm and up to 8 cm; (2) two to three lesions with at least one lesion >3 cm and not exceeding 5 cm, with total tumor diameter up to 8 cm; or (3) four to five lesions with none >3 cm, with total tumor diameter up to 8 cm. A minimum observation period of 3 months after down-staging was required before OLT. Tumor down-staging was successful in 43 patients (70.5%). Thirty-five patients (57.4%) had received OLT, including two who had undergone live-donor liver transplantation. Treatment failure was observed in 18 patients (29.5%), primarily due to tumor progression. In the explant of 35 patients who underwent OLT, 13 had complete tumor necrosis, 17 met T2 criteria, and five exceeded T2 criteria. The Kaplan-Meier intention-to-treat survival at 1 and 4 years after down-staging were 87.5% and 69.3%, respectively. The 1-year and 4-year posttransplantation survival rates were 96.2% and 92.1%, respectively. No patient had HCC recurrence after a median posttransplantation follow-up of 25 months. The only factor predicting treatment failure was pretreatment alpha-fetoprotein >1,000 ng/mL.

CONCLUSION

Successful down-staging of HCC can be achieved in the majority of carefully selected patients and is associated with excellent posttransplantation outcome.

Massive abdominal wall hemorrhage from injury to the inferior epigastric artery: a retrospective review

PURPOSE

To identify the etiology of inferior epigastric artery injury (IEAI) in patients referred to the interventional radiology service and determine the efficacy of diagnostic imaging and embolization in these patients.

MATERIALS AND METHODS

A retrospective review of patients referred to the interventional radiology departments at three university-affiliated hospitals from 1995 through 2007 was performed. Patients were identified and data were extracted from case log books and the electronic medical record.

RESULTS

Twenty IEAIs were identified in 19 patients. The etiology of arterial injury was paracentesis in eight (40%), surgical trauma in three (15%), percutaneous drain placement in three (15%), blunt trauma in two (10%), subcutaneous injection in one (5%), stabbing in one (5%), and unknown in two (10%). Fifteen of 19 patients (79%) had an underlying coagulopathy. The diagnosis was confirmed by contrast medium-enhanced computed tomography (CT) in 14 (70%), tagged red blood cell scan in two (10%), and noncontrast CT in one (5%). Three patients (15%) had no diagnostic imaging. Contrast medium-enhanced CT showed active extravasation in nine of 14 patients (64%) and 13 of 14 exhibited active extravasation on subsequent arteriography. The sensitivity and specificity of contrast medium-enhanced CT for demonstrating active arterial bleeding were 70% and 100%, respectively. All 20 IEAIs were treated with transcatheter embolization, with an overall success rate of 90% and no complications.

CONCLUSIONS

IEAI is most often an iatrogenic injury in a coagulopathic patient. Contrast medium-enhanced CT can be diagnostic for active bleeding, but in the setting of ongoing hemorrhage a negative study result should not preclude arteriography. Embolization is an effective means to control hemorrhage.

Hepatic arterial injuries after percutaneous biliary interventions in the era of laparoscopic surgery and liver transplantation: experience with 930 patients

PURPOSE

To retrospectively determine if patients with a history of intraoperative bile duct injury or liver transplantation have an increased risk for arterial injury (AI) during percutaneous transhepatic cholangiography (PTC) and percutaneous transhepatic biliary drainage (PTBD) compared with the risk of AI established in the 1970s and 1980s.

MATERIALS AND METHODS

This study was approved by the committee on human research and was deemed compliant with the Health Insurance Portability and Accountability Act. The informed consent requirement was waived. Records of 1394 procedures (307 PTCs, 1087 PTBDs) performed in 930 patients (445 male, 485 female; age range, 4 months to 99 years) over the past 13 years were retrospectively reviewed. The rate of AI was determined, and demographic, pathologic, technical, and laboratory variables were tested for association with increased risk of AI by using generalized estimating equation analysis.

RESULTS

AIs were encountered after 30 (2.2%) biliary procedures. No significant difference in the rate of AI was seen among the groups of patients with malignant biliary obstruction (1.8%), history of bile duct injury (2.2%), or complications of liver transplantation (2.6%). Patients who underwent PTBD had a higher risk of AI than did patients who underwent PTC (2.6% vs 0.7%); however, this difference was not significant (P = .06). Ongoing hemobilia was seen in 26 (87%) of the patients, which made it the most common sign of AI, and it had a 94% positive predictive value for AI. A postprocedure decrease in the hematocrit level of more than 13% was seen only in the setting of AI, and it occurred in only three (10%) of patients with AIs.

CONCLUSION

PTC and PTBD performed for management of bile duct injury and complications of liver transplantation are not associated with an increased risk of hepatic AIs compared with the risk of AI reported in the 1970s and 1980s.

Management of portal venous complications after liver transplantation

The postoperative vascular complications following liver transplantation, specifically portal venous complications, have been well documented. These complications, which include portal venous stenosis and thrombosis, can be potentially devastating and lead to graft failure. The interventional techniques in managing these complications are relatively new and have been developed only in the past 15 to 20 years. Additionally with the increasing numbers of split liver and living related transplants that are being performed, so has the incidence of portal venous complications increased. This article is a review of the current interventional techniques used in managing portal venous complications in the posttransplant patient. The topics covered include portal vein angioplasty, stenting, and thrombolysis with a description of the variety of techniques used to perform these procedures. The review also covers management of portal hypertension by creating a transjugular intrahepatic portosystemic shunt (TIPS).

Is adrenal venous sampling necessary in all patients with hyperaldosteronism before adrenalectomy?

PURPOSE

To evaluate whether selective rather than universal use of adrenal vein sampling (AVS) may be warranted in patients with hyperaldosteronism to characterize and lateralize disease before adrenalectomy.

MATERIALS AND METHODS

Fifty-nine consecutive patients with biochemically diagnosed hyperaldosteronism underwent unilateral adrenalectomy at a single center during a 10-year period. In one group (n = 30), adrenalectomy was based on computed tomography (CT) only; in another (n = 29), it was based on CT and AVS. The indication for AVS was equivocal CT finding (n = 26) or patient request (n = 3). Outcome variables were postoperative serum potassium and aldosterone levels, number of hypertensive medications, and mean arterial blood pressure at 6 months.

RESULTS

Preoperatively, both groups were matched for age, years of hypertension, mean arterial blood pressure, and number of hypertensive medications. Average tumor sizes were 2 cm (range, 1-3 cm) in the CT-only group and 1 cm (range, 0-2.5 cm) in the CT/AVS group. Unilateral tumor was identified on CT in 30 patients (100%) in the CT-only group and in 17 patients (59%) in the CT/AVS group (P < .05). Postoperatively, aldosterone levels were lower in the CT-only group (6.3 ng/dL +/- 5.9 vs 13.5 ng/dL +/- 16; P < .05). Both groups had similar improvements in mean arterial blood pressure at 6 months (92 mm Hg +/- 12 vs 96 mm Hg +/- 9; P = .14), reductions in number of hypertensive medications (to 1.1 +/- 1.3 vs 1.2 +/- 1.1; P = .4), and improvements in hypokalemia (3.8 mEq/L +/- 0.5 vs 3.8 mEq/L +/- 0.5; P = .5).

CONCLUSIONS

The clinical impact of adrenalectomy was similar in both groups. CT can be used to reliably diagnose adenomas larger than 1.0 cm. AVS should be used when CT findings are equivocal or both adrenal glands are abnormal.

Percutaneous Interventions in Subclavian Artery–to–Contralateral Subclavian Vein “Necklace” Hemodialysis Grafts: Experience in Five Patients

PURPOSE

To describe clinical outcomes of endovascular interventions in the setting of thrombosis or dysfunction of anterior chest wall ("necklace") arteriovenous (AV) hemodialysis grafts.

MATERIALS AND METHODS

Eight percutaneous interventions (balloon angioplasty, pharmacologic thrombolysis, and mechanical thrombectomy) were performed in five patients with anterior chest wall AV grafts. Primary, assisted, and secondary patencies, as well as technical success and complication rates, were determined.

RESULTS

The technical success rate of percutaneous interventions in re-establishing a normal blood flow pattern within the AV grafts was 100%. Primary patency ranged from one to 23 months (median, 5 months). Primary assisted patency and secondary patency were 36 months and 8 months, respectively, in two patients who underwent more than one intervention. Postintervention access patency ranged from 5 to 36 months (median, 9 months), whereas graft lifetime ranged from 12 to 45 months (median, 24 months). There were no complications related to revascularization procedures.

CONCLUSION

Percutaneous interventions can be performed safely and effectively in anterior chest wall AV grafts. Technical success and long-term patency rates appear to be similar to those of percutaneous interventions in upper-extremity hemodialysis AV grafts.

Safety and Efficacy of TIPS in Patients with Hemophilia and Cirrhosis

The prevalence of portal hypertension and its complications is increasing among patients with hemophilia and cirrhosis. The authors evaluated the safety and efficacy of transjugular intrahepatic postosystemic shunt (TIPS) placement in this population. A retrospective analysis was performed of adult patients who underwent TIPS placement at a single center. Four patients with hemophilia and cirrhosis were identified. Outcome measures included technical success and complications, recurrent gastrointestinal hemorrhage, shunt patency, hepatic encephalopathy, ascites control, and mortality. With periprocedural factor VIII supplementation, TIPS were placed in all patients without complications and with improvement in portal hypertension. Outcomes after TIPS placement appear to be comparable to those in patients without hemophilia.

Sharp recanalization of a short esophageal occluding stricture in a patient with epidermolysis bullosa

BACKGROUND

Although esophageal strictures caused by epidermolysis bullosa are often treated with balloon dilations, complete obstruction has few effective therapies except esophagectomy with colonic replacement.

OBJECTIVE

Resolution of esophageal obstructive lesion without surgical intervention.

DESIGN

Case study.

SETTING

Interventional radiology.

PATIENT

Epidermolysis bullosa with esophageal stricture.

INTERVENTION

Endoscopic- and guidewire-guided sharp recanalization.

MAIN OUTCOME MEASUREMENT

Radiologic evidence of stricture resolution.

RESULTS

Successful recanalization.

LIMITATIONS

Experience of operators (anesthesiologist, endoscopist, interventional radiologist).

CONCLUSIONS

Sharp recanalization of a complete stricture in patients with epidermolysis bullosa is feasible in a controlled setting.

Tesio Catheter Access for Long-term Maintenance Hemodialysis

PURPOSE

To retrospectively determine the long-term outcome (>6 months) of placement of tunneled hemodialysis catheters.

MATERIALS AND METHODS

The HIPAA-compliant study protocol was approved by the Committee on Human Research, which waived the requirement for informed consent. The records of patients who underwent hemodialysis with the Tesio system (Medcomp, Harleysville, Pa) at a single outpatient dialysis unit between March 1994 and March 2004 were reviewed. The length of catheter access and the requirements for percutaneous revision were recorded, and unassisted- and assisted-access survival times were computed by using the Kaplan-Meier method.

RESULTS

Three hundred three primary Tesio accesses were created in 200 patients (mean age, 62.3 years +/- 16.3 [standard deviation]; 102 women [51.0%]). Fifty-nine of 303 accesses (19.5%) were percutaneously revised with catheter exchange. During follow-up, 200 of 303 accesses (66.0%) were terminated (117 because they were no longer needed and 83 because of catheter malfunction), and 103 (34.0%) accesses were functioning at the time of last follow-up. The mean duration of catheter access was 247 days (range, 3-2016 days). One hundred twenty-six (41.6%) accesses remained in use for more than 6 months; 50 (16.5%), for more than 1 year; 20 (6.6%), for more than 2 years; 14 (4.6%), for more than 3 years; and five (1.7%), for more than 4 years. Assisted-access survival was 78.1%, 60.0%, 51.5%, 51.5%, and 46.8% at 6 months and 1, 2, 3, and 4 years, respectively.

CONCLUSION

Tesio catheters frequently function for periods longer than 6 months and, when necessary, they can function for many years.

Orthopedic Spinal and Hip Prostheses: Effects of Magnetic Susceptibility Artifacts during MR Arteriography and Venography of Abdomen and Pelvis

PURPOSE

To retrospectively determine if susceptibility artifacts from internal metallic spinal fixation devices and hip prostheses limit the depiction of vascular anatomy and pathologic abnormalities during magnetic resonance (MR) arteriography and venography.

MATERIALS AND METHODS

This study was approved by the Committee on Human Research of the Institutional Review Board, which waived the requirement for informed consent and deemed the study to be HIPAA compliant. Forty-two contrast material-enhanced MR angiographic examinations were performed by using a 1.5-T imager in 41 patients (16 men, 25 women; mean age, 57 years; range, 36-79 years); 33 of these examinations included both MR arteriographic and MR venographic components. On the basis of resolution, images for which more than 3 mm of vessels were affected by susceptibility artifacts were considered uninterpretable. The odds of obtaining an uninterpretable image due to metallic artifacts were calculated, and a chi(2) analysis was employed to determine significance.

RESULTS

Total hip prostheses and spinal hardware that terminated above the L5 level did not generate any appreciable artifacts at MR arteriography (P < .001) or MR venography (P = .002). In patients with hardware that extended to the sacrum, 88% of MR arteriograms were of diagnostic quality (P = .001), but only 21% of MR venograms were interpretable (P = .004). Artifacts limited the evaluation of the inferior vena cava and common iliac veins near the confluence.

CONCLUSION

Diagnostic-quality MR arteriograms and MR venograms can be obtained in patients with artificial hip prostheses and spinal hardware terminating above the L5 level, but there is 79% likelihood of obtaining a nondiagnostic MR venogram in patients with internal spinal fixation devices that extend to the sacrum.

Outcomes of Tracheobronchial Stent Placement for Benign Disease

PURPOSE

To retrospectively determine long-term outcomes in patients who have undergone tracheobronchial stent placement for benign diseases.

MATERIALS AND METHODS

Institutional Review Board approval was obtained for this retrospective HIPAA-compliant study, with waiver of informed consent. Forty patients (22 female, 18 male; mean age, 52.0 years) who were treated with metallic airway stents for benign stenosis were identified from an interventional radiology database. Causes of airway stenosis included transplant stricture (n = 13), tracheal tube injury (n = 10), inflammation (n = 6), tracheobronchomalacia (n = 4), infection (n = 3), and extrinsic compression (n = 4). Follow-up, which ranged from 6 to 2473 days, was performed by means of chart review for deceased patients and by means of clinical visit or telephone interview for surviving patients. Survival, primary patency, and assisted patency were estimated by using the Kaplan-Meier product limits method.

RESULTS

Initial technical success was achieved in all cases. Symptomatic improvement was present in 39 of 40 cases. At review, 15 patients were alive and had clinical improvement, 18 had died of comorbid causes, one had died of uncertain causes, three had undergone subsequent airway surgery, two had undergone airway stent retrieval, and one was lost to follow-up. Survival at 1, 2, 3, 4, 5, and 6 years was 79%, 76%, 51%, 47%, 38%, and 23%, respectively. Loss of primary patency was most rapid during the 1st year. With repeat intervention, assisted patency was 90% at 6.8 years.

CONCLUSION

Attrition of tracheobronchial stent patency is most rapid during the 1st year, and a high rate of long-term patency can be achieved with secondary interventions. Metallic airway stents are well-tolerated and useful adjuncts for management of select benign tracheobronchial stenoses.

A prospective study on downstaging of hepatocellular carcinoma prior to liver transplantation

In patients with hepatocellular carcinoma (HCC) exceeding conventional (T2) criteria for orthotopic liver transplantation (OLT), the feasibility and outcome following loco-regional therapy intended for tumor downstaging to meet T2 criteria for OLT are unknown. In this first prospective study on downstaging of HCC prior to OLT, the eligibility criteria for enrollment into a downstaging protocol included 1 lesion >5 cm and < or =8 cm, 2 or 3 lesions at least 1 >3 cm but < or =5 cm with total tumor diameter of < or =8 cm, or 4 or 5 nodules all < or =3 cm with total tumor diameter < or =8 cm. Patients were eligible for living-donor liver transplantation (LDLT) if tumors were downstaged to within proposed University of California, San Francisco (UCSF) criteria.13 A minimum follow-up period of 3 months after downstaging was required before cadaveric OLT or LDLT, with imaging studies meeting criteria for successful downstaging. Among the 30 patients enrolled, 21 (70%) met criteria for successful downstaging, including 16 (53%) who had subsequently received OLT (2 with LDLT), and 9 patients (30%) were classified as treatment failures. In the explant of 16 patients who underwent OLT, 7 had complete tumor necrosis, 7 met T2 criteria, but 2 exceeded T2 criteria. No HCC recurrence was observed after a median follow-up of 16 months after OLT. The Kaplan-Meier intention-to-treat survival was 89.3 and 81.8% at 1 and 2 yr, respectively. In conclusion, successful tumor downstaging can be achieved in the majority of carefully selected patients, but longer follow-up is needed to further access the risk of HCC recurrence after OLT.

Management of patients with "ex vacuo" pneumothorax after thoracentesis

RATIONALE AND OBJECTIVES

To determine clinical outcome in patients who developed "ex vacuo" pneumothorax following thoracentesis and to assess the benefit of chest tube placement for this complication.

MATERIALS AND METHODS

We retrospectively reviewed records of 282 patients who underwent 437 thoracenteses at a single institution during a 6-year period. We identified 34 patients (12.1%) who developed a pneumothorax following 39 thoracenteses (8.8%) and then identified a subset of patients with pneumothorax "ex vacuo" defined as a moderate to large hydropneumothorax or small pneumothorax persisting for more than 3 days. Patient charts were reviewed to document the treatment strategy employed and subsequent clinical outcome, which included length of hospital stay, resolution of pneumothorax, reaccumulation of pleural effusion, and overall survival.

RESULTS

Ten patients developed "ex vacuo" pneumothroax following thoracentesis. None complained of significant worsening of symptoms following thoracentesis. Seven patients were treated by observation alone and 3 patients underwent tube thorocostomy. A decrease in size of the pneumothorax was observed in only 3 patients, none of whom had a chest tube placed. Effusion completely reaccumulated in 7 patients. All 10 patients died during the follow-up period; the mean survival was 157 days (range: 13-402 days). Survival among patients treated by observation was 191.4 days versus 71.7 days for patients receiving chest tubes.

CONCLUSION

Life expectancy for most patients who develop "ex vacuo" pneumothorax following therapeutic thoracentesis is short (<6 months). Chest tube placement is not necessary in asymptomatic patients and is unlikely to provide clinical benefit.

Percutaneous Salvage of a Failing Rex Shunt

Creation of a mesenterico-left portal vein (PV) shunt with use of autologous internal jugular vein (ie, Rex shunt) is a surgical option for the treatment of symptomatic extrahepatic PV occlusion. Herein a patient is described who underwent angioplasty and stent placement across a shunt stenosis by ultrasound (US)--guided percutaneous transhepatic portal access. Follow-up US has demonstrated continued shunt patency.

Large Asymptomatic Hydropneumothorax after Thoracentesis

The interventional radiology Case Corner Series is a new feature that will be presented quarterly in JVIR. The format is uniquely designed for the busy interventional radiology practitioner. Case presentations are short and to the point. Discussions are succinct and pertinent to current practice. Each quarter, a difficult or problem case is presented and the reader is challenged with questions relevant to the case. Short answers are then provided based on referenced sources from the current literature. Cases are drawn from the interventional radiology experience at the University of California San Francisco and are edited by Jeanne M. LaBerge, MD, and Robert K. Kerlan, Jr, MD.

Combination treatment of venous thoracic outlet syndrome: Open surgical decompression and intraoperative angioplasty

OBJECTIVE

Residual subclavian vein stenosis after thoracic outlet decompression in patients with venous thoracic outlet syndrome is often treated with postoperative percutaneous angioplasty (PTA). However, interval recurrent thrombosis before postoperative angioplasty is performed can be a vexing problem. Therefore we initiated a prospective trial at 2 referral institutions to evaluate the safety and efficacy of combined thoracic outlet decompression with intraoperative PTA performed in 1 stage.

METHODS

Over 3 years 25 consecutive patients (16 women, 9 men; median age, 30 years) underwent treatment for venous thoracic outlet syndrome with a standard protocol at 2 institutions. Twenty-one patients (84%) underwent preoperative thrombolysis to treat axillosubclavian vein thrombosis. First-rib resection was performed through combined supraclavicular and infraclavicular incisions. Intraoperative venography and subclavian vein PTA were performed through a percutaneous basilic vein approach. Postoperative anticoagulation therapy was not used routinely. Venous duplex ultrasound scanning was performed postoperatively and at 1, 6, and 12 months.

RESULTS

Intraoperative venography enabled identification of residual subclavian vein stenosis in 16 patients (64%), and all underwent intraoperative PTA with 100% technical success. Postoperative duplex scans documented subclavian vein patency in 23 patients (92%). Complications included subclavian vein recurrent thrombosis in 2 patients (8%), and both underwent percutaneous mechanical thrombectomy, with restoration of patency in 1 patient. One-year primary and secondary patency rates were 92% and 96%, respectively, at life-table analysis.

CONCLUSIONS

Residual subclavian vein stenosis after operative thoracic outlet decompression is common in patients with venous thoracic outlet syndrome. Combination treatment with surgical thoracic outlet decompression and intraoperative PTA is a safe and effective means for identifying and treating residual subclavian vein stenosis. Moreover, intraoperative PTA may reduce the incidence of postoperative recurrent thrombosis and eliminate the need for venous stent placement or open venous repair.

Incidence of important hemobilia following transhepatic biliary drainage: left-sided versus right-sided approaches

Our purpose here is to describe our experience with important hemobilia following PTBD and to determine whether left-sided percutaneous transhepatic biliary drainage (PTBD) is associated with an increased incidence of important hemobilia compared to right-sided drainages. We reviewed 346 transhepatic biliary drainages over a four-year period and identified eight patients (2.3%) with important hemobilia requiring transcatheter embolization. The charts and radiographic files of these patients were reviewed. The side of the PTBD (left versus right), and the order of the biliary ductal branch entered (first, second, or third) were recorded. Of the 346 PTBDs, 269 were right-sided and 77 were left-sided. Of the eight cases of important hemobilia requiring transcatheter embolization, four followed right-sided and four followed left-sided PTBD, corresponding to a bleeding incidence of 1.5% (4/269) for right PTBD and 5.2% (4/77) for left PTBD. The higher incidence of hemobilia associated with left-sided PTBD approached, but did not reach the threshold of statistical significance (p = 0.077). In six of the eight patients requiring transcatheter embolization, first or second order biliary branches were accessed by catheter for PTBD. All patients with left-sided bleeding had first or proximal second order branches accessed by biliary drainage catheters. In conclusion, a higher incidence of hemobilia followed left-versus right-sided PTBD in this study, but the increased incidence did not reach statistical significance.

Postoperative evaluation of complex aortovisceral and aortorenal reconstructions by magnetic resonance angiography

RATIONALE AND OBJECTIVES

To assess the ability of magnetic resonance angiography (MRA) to evaluate complex vascular bypass reconstructions of the abdominal aorta and its major branches in the postoperative period.

MATERIALS AND METHODS

Thirteen patients with bypass grafts connecting the aorta to visceral, renal, and lower limb inflow vessels were evaluated with MRA. Three of these patients were also studied with digital subtraction angiography soon after MRA was completed. MRA was evaluated for its ability to detect the grafts and to determine the degree of stenosis in the graft conduit or at the anastomoses to native vessels.

RESULTS

Detection of graft conduits and anastomotic sites by MRA was 100% and 99%, respectively. Comparison with digital subtraction angiography in a subset of the patients showed a 100% agreement between the two modalities in their description of stenotic disease in graft conduits and 95% agreement in stenosis characterization at graft anastomotic sites.

CONCLUSION

MRA of complex aortic reconstructions with bypass grafts to its major abdominal branches arteries accurately describes the resulting complicated vascular anatomy and likely has a high degree of correlation to digital subtraction angiography in describing the disease within the bypass grafts.

Inferior Vena Cava Thrombosis after Transjugular Intrahepatic Portosystemic Shunt Revision with a Covered Stent

A 42-year-old woman who had undergone multiple revisions of a bare-stent transjugular intrahepatic portosystemic shunt was treated for in-stent stenosis by insertion of a polytetrafluoroethylene (PTFE)-covered stent. Immediately after revision with the covered stent, she developed inferior vena cava (IVC) thrombosis. The potential causes and implications of this complication are discussed.

Massive vaginal hemorrhage after uterine fibroid embolization

A 48-year-old woman underwent uterine fibroid embolization (UFE) for menorrhagia. One-month after the procedure she developed massive vaginal bleeding and required an emergency hysterectomy. Pathologic evaluation of the uterus revealed ulceration of the endometrium overlying the necrotic fibroid. Physicians performing UFE should be aware of this rare but potentially life-threatening complication.

Experimental renal artery embolization in a combined MR imaging/angiographic unit

PURPOSE

The purpose of this study was to use a combined x-ray angiography and MR imaging (XMR) system to manipulate intraarterial catheters and monitor the deposition of gadolinium (Gd)-impregnated embolic microspheres in vivo in a canine kidney model.

MATERIALS AND METHODS

Seven anesthetized dogs (18-28 kg) were studied. The renal arteries were catheterized under fluoroscopic guidance. Renal blood flow rates were assessed with velocity-encoded cine MR imaging before and after renal artery embolization with Gd-impregnated microspheres (300-500 and 500-700 micro m in size). The particles were injected in vivo into 14 canine renal arteries under fast dynamic T1-weighted MR imaging guidance at one frame per second. Postembolic microsphere distributions were assessed with MR imaging and digital subtraction angiography (DSA).

RESULTS

Gd-impregnated microsphere injection into the renal arteries was successful in all animals. Renal enhancement due to the deposition of the particles persisted for at least 1 hour after the injection. The distribution of MR signal enhancement in the kidneys differed for the smaller versus the larger microspheres. The 300-500- micro m microspheres deposited preferentially in the outer cortical regions, whereas the 500-700- micro m microspheres preferentially deposited in the medulla and inner cortex. Renal blood flow was significantly reduced after the administration of both the 300-500- micro m microspheres (from 3.9 to 1.0 mL/min/g) and the 500-700- micro m microspheres (from 3.5 to 0.2 mL/min/g).

CONCLUSION

MR imaging permits real-time guidance of arterial embolization with Gd-impregnated microspheres.

Hepatocellular carcinoma: regional therapy with a magnetic targeted carrier bound to doxorubicin in a dual MR imaging/ conventional angiography suite--initial experience with four patients

Four patients with inoperable hepatocellular carcinoma were treated with a magnetic targeted carrier bound to doxorubicin (MTC-DOX) by using a joint magnetic resonance (MR) imaging/conventional angiography system consisting of a 1.5-T short-bore magnet connected to a C-arm angiography unit by a sliding tabletop. Selective transcatheter delivery of the MTC-DOX to the hepatic artery was monitored by using intraprocedural MR imaging, and interim catheter manipulation was performed with fluoroscopic guidance to optimize agent delivery to the tumor and minimize delivery to normal tissue. The final fraction of treated tumor volume ranged from 0.64 to 0.91. The fraction of affected normal liver volume ranged from 0.07 to 0.30. The dual MR imaging/conventional angiography system shows promise for directing magnetically targeted tumor therapies.

Coil Embolization of a Tuboovarian Anastomosis before Uterine Artery Embolization to Prevent Nontarget Particle Embolization of the Ovary

Uterine artery embolization (UAE) is being used more frequently as a primary treatment for uterine leiomyoma. Performing UAE in women who desire future fertility is controversial because of the risks of premature menopause and the undetermined effects on pregnancy. The etiology of ovarian failure after UAE is not yet clearly defined, but one of the leading possibilities is nontarget embolization of the ovaries. In this case report, the authors describe a technique of selective coil embolization of a uterine artery-to-ovarian artery communication before UAE performed specifically to protect the ovary from nontarget embolization.

Reversal of flow in the ovarian artery during uterine artery embolization

Uterine artery embolization (UAE) is gaining increasing recognition as an effective treatment alternative to hysterectomy in select patients. As interventional radiologists gain more experience in the treatment of fibroids, new interest is being directed toward arterial communications between the uterine arteries and ovarian arteries. This case report focuses on the potentially serious complication of flow reversal up the ovarian artery into the aorta during UAE.

Percutaneous mechanical thrombectomy for the management of venous thoracic outlet syndrome

PURPOSE

To describe the successful use of percutaneous mechanical thrombectomy as an adjunct to thrombolysis for acute subclavian vein thrombosis due to venous thoracic outlet syndrome.

CASE REPORT

A 40-year-old man presented with arm swelling due to acute subclavian vein thrombosis and venous thoracic outlet syndrome. Percutaneous mechanical thrombectomy with the AngioJet device and thrombolysis were used to restore venous patency. Immediately following operative thoracic outlet decompression, the patient experienced rethrombosis, which was successfully treated using percutaneous mechanical thrombectomy. After 6 months, the patient remains symptom-free, with a patent subclavian vein by duplex ultrasonography.

CONCLUSIONS

Thrombus debulking or removal with percutaneous mechanical thrombectomy devices may reduce the amount or duration of thrombolytic therapy required, making treatment of venous thoracic outlet syndrome safer. Moreover, patients with recurrent thrombosis after thoracic outlet decompression may be safely treated with percutaneous mechanical thrombectomy, even when thrombolytic therapy is contraindicated.

Evaluation of active bleeding into hematomas by technetium-99m red blood cell scintigraphy before angiography

PURPOSE

To evaluate the utility of technetium-99m red blood cell (Tc-99m RBC) scintigraphy in the diagnosis of active hemorrhage into large intra-abdominal hematomas before arteriography.

METHODS

This retrospective case series describes four patients (1 man and 3 women) with large abdominal wall and retroperitoneal hematomas confirmed by computed tomography who underwent Tc-99m RBC scintigraphy before angiography. Arterial transcatheter embolization was performed if active hemorrhage was found.

RESULTS

Three of the patients had positive findings on Tc-99m RBC scans, which showed spreading of the labeled erythrocytes into the hematoma space. Positive scintigraphy was diagnostic for active hemorrhage and helped localize the bleeding sites. Angiography confirmed the diagnosis in all patients with positive scintigraphy and ruled out active bleeding in the patient with a negative Tc-99m-labeled RBC scan.

CONCLUSION

Tc-99m RBC scintigraphy appears to be sensitive and accurate in detecting active hemorrhage into intra-abdominal hematomas.

MR portal venography: preliminary results of fast acquisition without contrast material or breath holding

RATIONALE AND OBJECTIVES

The authors performed this study to evaluate the feasibility of using the steady-state free precession (SSFP) sequence to perform magnetic resonance (MR) venography of the portal venous system without the use of contrast material or breath holding.

MATERIALS AND METHODS

Eleven patients underwent MR venography with the SSFP technique. Coronal three-dimensional images were obtained with respiratory triggering. Contrast material and respiratory suspension were not used. All patients had recently undergone at least one other imaging study (conventional angiography, transhepatic portal venography, ultrasound, or contrast-enhanced computed tomography), and these findings were correlated with those from MR venography. The structures evaluated were the main portal vein, right portal vein, left portal vein, superior mesenteric vein, and splenic vein.

RESULTS

MR venography with SSFP accurately depicted the status of these veins in all cases except one. In this patient, MR venography depicted portal vein thrombus but could not indicate that it was tumor thrombus.

CONCLUSION

MR venography with SSFP accurately depicted the portal venous system in 10 of 11 patients without the use of respiratory suspension or contrast material.

Integrated fellowship in vascular surgery and intervention radiology: a new paradigm in vascular training

OBJECTIVE

To evaluate an integrated fellowship in vascular surgery and interventional radiology initiated to train vascular surgeons in endovascular techniques and to train radiology fellows in clinical aspects of vascular diseases.

SUMMARY BACKGROUND DATA

The rapid evolution of endovascular techniques for the treatment of vascular diseases requires that vascular surgeons develop proficiency in these techniques and that interventional radiologists develop proficiency in the clinical evaluation and management of patients who are best treated with endovascular techniques. In response to this need the authors initiated an integrated fellowship in vascular surgery and interventional radiology and now report their interim results.

METHODS

Since 1999 vascular fellows and radiology fellows performed an identical year-long fellowship in interventional radiology. During the fellowship, vascular surgery and radiology fellows perform both vascular and nonvascular interventional procedures. Both vascular surgery and radiology-based fellows spend one quarter of the year on the vascular service performing endovascular aortic aneurysm repairs and acquiring clinical experience in the vascular surgery inpatient and outpatient services. Vascular surgery fellows then complete an additional year-long fellowship in vascular surgery. To evaluate the type and number of interventional radiology procedures, the authors analyzed records of cases performed by all interventional radiology and vascular surgery fellows from a prospectively maintained database. The attitudes of vascular surgery and interventional radiology faculty and fellows toward the integrated fellowship were surveyed using a formal questionnaire.

RESULTS

During the fellowship each fellow performed an average of 1,201 procedures, including 808 vascular procedures (236 diagnostic angiograms, 70 arterial interventions, 59 diagnostic venograms, 475 venous interventions, and 43 hemodialysis graft interventions) and 393 nonvascular procedures. On average fellows performed 20 endovascular aortic aneurysm repairs per year. There was no significant difference between the vascular surgery and radiology fellows in either the spectrum or number of cases performed. Eighty-eight percent (23/26) of the questionnaires were completed and returned. Both interventional radiologists and vascular surgeons strongly supported the integrated fellowship model and favored continuation of the integrated program. Vascular surgery and interventional radiology faculty members wanted additional training in clinical vascular surgery for the radiology-based fellows. With the exception of the radiology fellows there was uniform agreement that vascular surgery fellows benefit from training in nonvascular aspects of interventional radiology.

CONCLUSIONS

Integration of vascular surgery and interventional radiology fellowships is feasible and is mutually beneficial to both disciplines. Furthermore, the integrated fellowship provides exceptional training for vascular surgery and interventional radiology fellows in all catheter-based techniques that far exceeds the minimum requirements for credentialing suggested by various professional societies. There is a clear need for cooperation and active involvement on the parts of the American Board of Radiology and the American Board of Surgery and its Vascular Board to create hybrid training programs that meet mutually agreed-on criteria that document sufficient acquisition of both the cognitive and technical skills required to manage patients undergoing endovascular procedures safely and effectively.

Benign tracheobronchial stenoses: changes in short-term and long-term pulmonary function testing after expandable metallic stent placement

PURPOSE

To determine the short- and long-term improvement in airflow dynamics in patients undergoing tracheobronchial stent placement for benign airway stenoses.

METHODS

Twenty-two patients underwent 34 tracheal and/or bronchial stent placement procedures for benign airway stenoses and had the results of pulmonary function tests available. Stent placement indications included bronchomalacia after lung transplantation (n = 11), postintubation stenoses (n = 6), relapsing polychondritis (n = 2), and 1 each of tracheomalacia, tracheal compression, and histoplasmosis. Six patients underwent more than one stent placement procedure (range: 2-7 procedures). The mean forced expiratory volume in one second (FEV(1) ), forced expiratory flow rate in the midportion of the forced vital capacity curve (FEF(25-75) ), forced vital capacity, and peak flow (PF) rate obtained before stent placement were compared with those immediately after stent placement and with those measurements most remote from stent placement using the paired two-tailed test.

RESULTS

All patients reported improved respiratory function immediately after stent placement. The mean FEV(1), FEF(25-75), and PF rate improved significantly (p < 0.001, p = 0.002, and p = 0.009, respectively) after stent placement. On long-term follow-up averaging 15 months after stent placement, these parameters declined despite patients' subjective sense of improvement. Segregating the population into transplant and nontransplant airway stenosis etiologies, however, FEF(25-75) and PF rate remained significantly improved (p = 0.045, p = 0.027, respectively), over the long term for the latter. FEV increased after subsequent stent placements for patients receiving multiple stents.

CONCLUSION

Stent placement for benign tracheobronchial stenoses provides significant immediate improvement in airflow dynamics. Long-term improvement in airflow obstruction may be expected, and additional stent placements may further improve pulmonary function.

Real-time MR properties of particulate embolic agents tested in a dynamic flow model

PURPOSE

Interventional magnetic resonance (MR)-guided transcatheter embolization could potentially limit radiation exposure and improve visualization of target organs. The feasibility of monitoring injection and distribution of embolic agents was assessed in a dynamic flow model with real-time MR imaging.

MATERIALS AND METHODS

MR-compatible flow models were constructed with use of clear plastic chambers containing 170-microm polyethylene tubular filters. Gadolinium (Gd)-impregnated polyvinyl alcohol (PVA) particles (355-500 and 500-710 microm in size) and Gd-impregnated microspheres (Embospheres, 300-500 and 500-700 microm in size) were injected into the flow circuit under real-time dynamic T1-weighted fast field echo guidance at four images per second. A dynamic steady-state free precession sequence at four images per second was used to monitor the injection of unmodified Embo-Gold 700-900- microm particles. High-resolution scans were obtained before and after each particle injection.

RESULTS

MR signal enhancement on the dynamic T1-weighted fast field echo sequence was visible during the injection of Gd-impregnated microspheres. Gd-impregnated PVA particles were not detected by this sequence. After injection, microsphere and PVA localization to the filter chambers was confirmed by the high-resolution scans. On the high-resolution sequences, relative MR signal enhancement of the microspheres was higher than that of the PVA particles. The Embo-Gold particles were minimally detectable on the dynamic sequence and undetectable by the high-resolution scan. After particle injection, direct inspection of the filter chamber showed trapping of all particle types and sizes.

CONCLUSION

Real-time MR tracking of Gd-impregnated embolic agents is possible in vitro.