William T Kuo

Stanford University, Stanford, California, United States

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Publications (41)170.05 Total impact

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    ABSTRACT: Purpose To study the comparative short-term safety and efficacy of transcatheter arterial chemoembolization (TACE) with drug-eluting LC Beads loaded with doxorubicin (DEBDOX), doxorubicin-eluting QuadraSpheres (hqTACE), and conventional TACE using ethiodized oil for superselective C-arm computed tomography (CT)-guided treatment of hepatocellular carcinoma (HCC) after the onset of drug shortages. Materials and Methods From March 2010 to March 2011, 166 patients with HCC were treated with 232 superselective TACE procedures using C-arm cone-beam CT at one institution. Patients underwent treatment depending on the availability of materials after the onset of drug shortages. Conventional TACE with doxorubicin, cisplatin, and Ethiodol was performed for 159 procedures, DEBDOX TACE was performed for 47, and hqTACE was performed for 26. Toxicity and objective response were compared at 3 months after treatment. Data were stratified for the high-risk population (Child-Pugh class B, performance status 1, bilobar disease, and/or post-resection recurrence) and initial versus repeat treatment. Kruskal-Wallis H test, Mann-Whitney U test, and Fisher exact test were used to compare the groups, with Bonferroni correction where needed. Results Whole liver response rates trended higher for conventional TACE (conventional TACE, 65.4%; DEBDOX, 63.8%; hqTACE, 53.8%) (P = .085). Only minor trends for differences in toxicity were observed between the three groups. Low-risk patients had higher whole liver (P = .001) and treated lesion (P = .007) response rates when treated with conventional TACE, but no significant differences were seen for DEBDOX and hqTACE. Treatment-naive patients also had higher whole liver (P = .012) and treated lesion (P = .056) response rates. No advantages for drug-eluting microspheres were found. Conclusion Within statistical power limitations, overall toxicity and efficacy were equivalent in patients treated with LC Beads, QuadraSpheres, or ethiodized oil emulsions, including in high-risk patients, when performed superselectively with cone-beam C-arm CT guidance. (©) RSNA, 2015.
    No preview · Article · Sep 2015 · Radiology
  • William T. Kuo · Miguel A. De Gregorio

    No preview · Article · Sep 2015 · Chest
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    ABSTRACT: Systemic thrombolysis for acute PE carries up to a 20% risk of major bleeding, including a 2-5% risk of hemorrhagic stroke. We evaluated the safety and effectiveness of catheter-directed therapy (CDT) as an alternative treatment for acute PE. One hundred one consecutive patients receiving CDT for acute PE were prospectively enrolled in a multicenter registry. Massive PE (n=28) and submassive PE (n=73) were treated with immediate catheter-directed mechanical or pharmacomechanical thrombectomy and/or catheter-directed thrombolysis via low-dose hourly drug infusion with tPA or urokinase. Clinical success was defined as meeting all criteria: stabilization of hemodynamics, improvement in pulmonary hypertension and/or right heart strain, and survival to hospital discharge. Primary safety outcomes were major procedure-related complications and major bleeding events. There were 53 men and 48 women with average age of 60 years (range, 22-86 years) and mean BMI of 31.03±7.20 kg/m2. The average thrombolytic doses were 28.0±11 mg tPA (n=76) and 2,697,101±936,287 IU for urokinase (n=23). Clinical success was achieved in 24/28 (85.7%)(95% CI, 67.3%-96.0%) patients with massive PE and 71/73 (97.3%)(95% CI, 90.5%-99.7%) with submassive PE. The mean PA pressure improved from 51.17±14.06 mmHg to 37.23±15.81 mmHg (n=92)(P<0.0001). Among patients monitored with follow-up echocardiography, 57/64 (89.1%)(95% CI, 78.8%-95.5%)(p<0.0001) showed improvement in right heart strain. There were no major procedure-related complications, no major hemorrhages, and no hemorrhagic strokes. Catheter-directed therapy improves clinical outcomes in acute PE patients while minimizing the risk of major bleeding. At experienced centers, CDT is a safe and effective treatment for both acute massive and submassive PE. NCT01097928, available at http://clinicaltrials.gov/show/NCT01097928.
    No preview · Article · Apr 2015 · Chest
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    ABSTRACT: The purpose of the study is to evaluate the influence of respiratory-induced vena caval hemodynamic changes on filter migration/penetration. After placement of either a Gunther Tulip or Celect IVC filter, 101 consecutive patients scheduled for filter retrieval were prospectively enrolled in this study. Pre-retrieval CT scans were used to assess filter complications and to calculate cross-sectional area in three locations: at level of filter strut fixation, 3 cm above and 3 cm below. A 3D finite element simulation was constructed on these data and direct IVC pressure was recorded during filter retrieval. Cross-sectional areas and pressures of the vena cava were measured during neutral breathing and in Valsalva maneuver and identified filter complications were recorded. A statistical analysis of these variables was then performed. During Valsalva maneuvers, a 60 % decrease of the IVC cross-sectional area and a fivefold increase in the IVC pressure were identified (p < 0.001). There was a statistically significant difference in the reduction of the cross-sectional area at the filter strut level (p < 0.001) in patient with filter penetration. Difficulty in filter retrieval was higher in penetrated or tilted filters (p < 0.001; p = 0.005). 3D computational models showed significant IVC deformation around the filter during Valsalva maneuver. Caval morphology and hemodynamics are clearly affected by Valsalva maneuvers. A physiological reduction of IVC cross-sectional area is associated with higher risk of filter penetration, despite short dwell times. Physiologic data should be used to improve future filter designs to remain safely implanted over longer dwell times.
    Full-text · Article · Mar 2015 · CardioVascular and Interventional Radiology
  • William T Kuo · Scott W Robertson
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    ABSTRACT: A 46-year-old woman underwent inferior vena cava filter placement before bariatric surgery and returned within 6 months for routine removal. She complained of a 1-week history of severe chest pain, and during retrieval, two fractured filter components were identified including one arm in the right ventricle. The filter body and one fragment were successfully retrieved, but the fragment in the right ventricle was refractory to percutaneous retrieval. During open-heart surgery, the fragment was found traversing through the ventricular wall resulting in cardiac tamponade. Electron microscopic fragment analysis revealed high-cycle metal fatigue indicating the filter design failed to withstand this patient's natural inferior vena cava biomechanical motions. Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Jan 2015 · Journal of vascular and interventional radiology: JVIR
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    ABSTRACT: To optimize surveillance schedules for the detection of recurrent hepatocellular carcinoma (HCC) after liver-directed therapy. New methods have emerged that allow quantitative analysis and optimization of surveillance schedules for diseases with substantial rates of recurrence such as HCC. These methods were applied to 1,766 consecutive chemoembolization, radioembolization, and radiofrequency ablation procedures performed on 910 patients between 2006 and 2011. Computed tomography or magnetic resonance imaging performed just before repeat therapy was set as the time of "recurrence," which included residual and locally recurrent tumor as well as new liver tumors. Time-to-recurrence distribution was estimated by Kaplan-Meier method. Average diagnostic delay (time between recurrence and detection) was calculated for each proposed surveillance schedule using the time-to-recurrence distribution. An optimized surveillance schedule could then be derived to minimize the average diagnostic delay. Recurrence is 6.5 times more likely in the first year after treatment than in the second. Therefore, screening should be much more frequent in the first year. For eight time points in the first 2 years of follow-up, the optimal schedule is 2, 4, 6, 8, 11, 14, 18, and 24 months. This schedule reduces diagnostic delay compared with published schedules and is cost-effective. The calculated optimal surveillance schedules include shorter-interval follow-up when there is a higher probability of recurrence and longer-interval follow-up when there is a lower probability. Cost can be optimized for a specified acceptable diagnostic delay or diagnostic delay can be optimized within a specified acceptable cost. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Nov 2014 · Journal of vascular and interventional radiology: JVIR
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    ABSTRACT: Aim: To study changes produced within the inferior vena cava (IVC) during respiratory movements and identify their possible clinical implications. Methods: This study included 100 patients (46 women; 54 men) over 18 years of age who required an abdominal computed tomography (CT) and central venous access. IVC cross-sectional areas were measured on CT scans at three levels, suprarenal (SR), juxtarenal (JR) and infrarenal (IR), during neutral breathing and again during the Valsalva maneuver. All patients were instructed on how to perform a correct Valsalva maneuver. In order to reduce the total radiation dose in our patients, low-dose CT protocols were used in all patients. The venous blood pressure (systolic, diastolic and mean) was invasively measured at the same three levels with neutral breathing and the Valsalva maneuver during venous port implantation. From CT scans, three-dimensional models of the IVC were constructed and a collapsibility index was calculated for each patient. These data were then correlated with venous pressures and cross-sectional areas. Results: The mean patient age was 51.64 ± 12.01 years. The areas of the ellipse in neutral breathing were 394.49 ± 85.83 (SR), 380.10 ± 74.55 (JR), and 342.72 ± 49.77 mm(2) (IR), and 87.46 ± 18.35 (SR), 92.64 ± 15.36 (JR) and 70.05 ± 9.64 mm(2) (IR) during the Valsalva (Ps < 0.001). There was a correlation between areas in neutral breathing and in the Valsalva maneuver (P < 0.05 in all areas). Large areas decreased more than smaller areas. The collapsibility indices were 0.49 ± 0.06 (SR), 0.50 ± 0.04 (JR) and 0.50 ± 0.04 (IR), with no significant differences in any region. Reconstructed three-dimensional models showed a flattening of the IVC during Valsalva, adopting an ellipsoid cross-sectional shape. The mean pressures with neutral breathing were 9.44 ± 1.78 (SR), 9.40 ± 1.44 (JR) and 8.84 ± 1.03 mmHg (IR), and 81.08 ± 21.82 (SR), 79.88 ± 19.01 (JR) and 74.04 ± 16.56 mmHg (IR) during Valsalva (Ps < 0.001). There was a negative correlation between cross-sectional caval area and venous blood pressure, but this was not statistically significant in any of the cases. There was a significant correlation between diastolic and mean pressures measured during neutral breathing and in Valsalva. Conclusion: Respiratory movements have a major influence on IVC dynamics. The increase in intracaval pressure during Valsalva results in a significant decrease in the IVC cross-sectional area.
    Full-text · Article · Oct 2014
  • William T Kuo · Steven E Deso · Scott W Robertson
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    ABSTRACT: A 48-year-old man presented with symptomatic inferior vena cava (IVC) occlusion from a chronically thrombosed and embedded Vena Tech LGM filter resulting in exercise intolerance from diminished cardiac preload and postthrombotic syndrome from chronic venous insufficiency. The patient was treated using a new PRIME technique-Piecemeal Removal by Intentional MEchanical fracture-to achieve successful filter retrieval 16 years after implantation. Removal of the obstructing filter permitted endovascular IVC recanalization with restoration of venous outflow and alleviation of venous obstructive symptoms. Cardiac preload was restored, allowing the patient to resume long-distance running, and he successfully completed a half-marathon 3 months after treatment.
    No preview · Article · Nov 2013 · Journal of vascular and interventional radiology: JVIR
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    ABSTRACT: BACKGROUND: ALTHOUGH CHRONICALLY IMPLANTED INFERIOR VENA CAVA FILTERS MAY RESULT IN FILTER-RELATED MORBIDITY, THERE IS CURRENTLY NO ROUTINE OPTION FOR REMOVING SUCH FILTERS WHEN THEY BECOME FIRMLY EMBEDDED ALONG THE VENA CAVA ENDOTHELIUM.METHODS AND RESULTS: DURING A 3-YEAR PERIOD, 100 CONSECUTIVE PATIENTS WERE PROSPECTIVELY ENROLLED IN A SINGLE-CENTER STUDY. THERE WERE 42 MEN AND 58 WOMEN (MEAN AGE, 46 YEARS; LIMITS, 1876 YEARS). RETRIEVAL INDICATIONS INCLUDED FILTER-RELATED ACUTE INFERIOR VENA CAVA THROMBOSIS, CHRONIC INFERIOR VENA CAVA OCCLUSION, AND PAIN FROM RETROPERITONEAL OR BOWEL PENETRATION. FILTER RETRIEVAL WAS ALSO PERFORMED TO PREVENT RISKS FROM PROLONGED IMPLANTATION AND TO POTENTIALLY ELIMINATE THE NEED FOR LIFELONG ANTICOAGULATION. AFTER STANDARD METHODS FAILED, PHOTOTHERMAL TISSUE ABLATION WAS ATTEMPTED WITH A LASER SHEATH POWERED BY A 308-NM XENON CHLORIDE EXCIMER LASER. APPLIED FORCES WERE RECORDED WITH A DIGITAL TENSION METER BEFORE AND DURING LASER ACTIVATION. LASER-ASSISTED RETRIEVAL WAS SUCCESSFUL IN 98.0% (95% CONFIDENCE INTERVAL [CI], 93.0%99.8%) WITH MEAN IMPLANTATION OF 855 DAYS (LIMITS, 376663 DAYS; 18 YEARS). GNTHER-TULIP (N=34), CELECT (N=12), OPTION (N=17), OPTEASE (N=20, 1 FAILURE), TRAPEASE (N=6, 1 FAILURE), SIMON-NITINOL (N=1), 12F STAINLESS STEEL GREENFIELD (N=4), AND TITANIUM GREENFIELD (N=6). THE AVERAGE FORCE DURING FAILED STANDARD RETRIEVALS WAS 7.2 VERSUS 4.6 POUNDS DURING LASER-ASSISTED RETRIEVALS (P0.0001). THE MAJOR COMPLICATION RATE WAS 3.0% (95% CI, 0.6%8.5%), THE MINOR COMPLICATION RATE WAS 7.0% (95% CI, 0.3%13.9%), AND THERE WERE 4 ADVERSE EVENTS (2 COAGULOPATHIC HEMORRHAGES, 1 RENAL INFARCTION, AND 1 CHOLECYSTITIS; 4.0%; 95% CI, 1.1%9.9%) AT MEAN FOLLOW-UP OF 500 DAYS (LIMITS, 841079 DAYS). SCAR TISSUE ABLATION WAS HISTOLOGICALLY CONFIRMED IN 96.0% (95% CI, 89.9%98.9%). SUCCESSFUL RETRIEVAL ALLOWED CESSATION OF ANTICOAGULATION IN 30 OF 30 (100%) PATIENTS AND ALLEVIATED MORBIDITY IN 23 OF 24 PATIENTS (96%).CONCLUSIONS: EXCIMER LASERASSISTED REMOVAL IS EFFECTIVE IN REMOVING EMBEDDED INFERIOR VENA CAVA FILTERS REFRACTORY TO STANDARD RETRIEVAL AND HIGH FORCE. THIS METHOD CAN BE SAFELY USED TO PREVENT AND ALLEVIATE FILTER-RELATED MORBIDITY.CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01158482.
    Preview · Article · Sep 2013 · Circulation Cardiovascular Interventions
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    ABSTRACT: Purpose: To evaluate clinical outcomes, characterize adherent tissue, and analyze inferior vena cava (IVC) filter fractures in patients undergoing complex retrieval for management of filter-related complications. To elucidate mechanisms of filter fracture by radiographic and electron microscopic (EM) evaluation. Materials and methods: Over 2.5 years, 50 consecutive patients with fractured and/or penetrating filter components were prospectively enrolled into a single-center study. There were 19 men and 31 women (mean age, 42 y; range, 15-73 y). All patients underwent complex filter retrieval after failure of standard methods, and retrieval indications along with resultant clinical outcomes were evaluated. Specimens with adherent tissue underwent histologic analysis, and all fractured components were studied with EM. Results: Retrieval was successful in all 50 cases (mean implantation, 815 d; range, 20-2,599 d) among the following filters: G2X (n = 23),G2 (n = 9), Eclipse (n = 3), Recovery (n = 4), ALN (n = 1), Celect (n = 7), OptEase (n = 2), and Simon Nitinol (n = 1). Mean indwell time in fractured filters (n = 31) was 1,082 days, versus 408 days in nonfractured filters (n = 19; P = .00169). Neointimal hyperplasia/fibrosis was seen in 46 of 48 specimens with adherent tissue (96%). Among 61 fractured components from conical filters, 35 had extravascular penetration whereas 26 remained intravascular (11 free-floating in IVC, 15 embolized centrally), and EM revealed fracture modes of high-cycle fatigue (n = 53), overload (n = 6), and indeterminate (n = 2). Following retrieval, previously prescribed lifelong anticoagulation was discontinued in 30 of 31 patients (97%). Filter-related symptoms from IVC occlusion, component embolization, and penetration-induced abdominal pain, duodenal injury, and/or small-bowel volvulus were alleviated in all 26 cases (100%). There were no long-term complications at a mean follow-up of 371 days (range, 67-878 d). Conclusions: The risk of filter fracture increases after 408 days (ie,>1 y) of implantation and is associated with symptomatic extravascular penetration and/or intravascular embolization. Complex methods can be used to safely remove these devices, alleviate filter-related morbidity, and allow cessation of anticoagulation.
    No preview · Article · Mar 2013 · Journal of vascular and interventional radiology: JVIR
  • William T Kuo

    No preview · Article · Jan 2013 · Journal of vascular and interventional radiology: JVIR
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    ABSTRACT: Compression of the left common iliac vein (CIV; LCIV) is a known risk factor for lower-extremity deep vein thrombosis (DVT). This study was performed to model the probability of DVT based on LCIV diameter and apply this to a quantitative DVT risk factor scoring system. Medical records were used to identify female patients younger than 45 years of age who were diagnosed with lower-extremity DVT (n = 21) and age-matched control subjects (n = 26) who presented to the emergency department with abdominal pain. Minimum CIV diameters were measured on computed tomography. Based on published reporting standards, 13 risk factors were scored for patients diagnosed with left-sided DVT and for control subjects. The association between vein diameter and DVT was examined by Mann-Whitney test. Odds of DVT based on vein diameter was assessed by logistic regression. Mean minimum LCIV diameters were 4.0 mm for patients with DVT and 6.5 mm for patients without DVT (P = .001). The odds of left DVT increased by a factor of 1.68 for each millimeter decrease in LCIV diameter (odds ratio = 1.68; P = .006; 95% confidence interval, 1.16-2.43). As the risk factor score increased, the relationship between diameter and risk for DVT became stronger; identical LCIV diameters were associated wtih a higher probability of developing DVT if the risk factor score was higher. Stenosis of the LCIV was found to be a strong independent risk factor for development of DVT. Moreover, each millimeter decrease in CIV diameter increased the odds of DVT by a factor of 1.68.
    No preview · Article · Nov 2012 · Journal of vascular and interventional radiology: JVIR
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    ABSTRACT: To determine the feasibility and efficacy of applying an established innovation process to an active academic interventional radiology (IR) practice. The Stanford Biodesign Medical Technology Innovation Process was used as the innovation template. Over a 4-month period, seven IR faculty and four IR fellow physicians recorded observations. These observations were converted into need statements. One particular need relating to gastrostomy tubes was diligently screened and was the subject of a single formal brainstorming session. Investigators collected 82 observations, 34 by faculty and 48 by fellows. The categories that generated the most observations were enteral feeding (n = 9, 11%), biopsy (n = 8, 10%), chest tubes (n = 6, 7%), chemoembolization and radioembolization (n = 6, 7%), and biliary interventions (n = 5, 6%). The output from the screening on the gastrostomy tube need was a specification sheet that served as a guidance document for the subsequent brainstorming session. The brainstorming session produced 10 concepts under three separate categories. This formalized innovation process generated numerous observations and ultimately 10 concepts to potentially to solve a significant clinical need, suggesting that a structured process can help guide an IR practice interested in medical innovation.
    No preview · Article · Apr 2012 · Journal of vascular and interventional radiology: JVIR
  • William T Kuo
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    ABSTRACT: Acute pulmonary embolism (PE) is the third most common cause of death among hospitalized patients. Treatment escalation beyond anticoagulation therapy is necessary in patients with massive PE (defined by hemodynamic shock) as well as in many patients with submassive PE (defined by right ventricular strain). The best current evidence suggests that modern catheter-directed therapy to achieve rapid central clot debulking should be considered as an early or first-line treatment option for patients with acute massive PE; and emerging evidence suggests a catheter-directed thrombolytic infusion should be considered as adjunctive therapy for many patients with acute submassive PE. This article reviews the current approach to endovascular therapy for acute PE in the context of appropriate diagnosis, risk stratification, and management of acute massive and acute submassive PE.
    No preview · Article · Dec 2011 · Journal of vascular and interventional radiology: JVIR
  • Lawrence V Hofmann · William T Kuo

    No preview · Article · Dec 2011 · The Lancet
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    ABSTRACT: To review the clinical course of patients with acute cholecystitis treated by percutaneous cholecystostomy, and to identify risk factors retrospectively that predict outcome. A total of 106 patients diagnosed with acute cholecystitis were treated by percutaneous cholecystostomy during a 10-year period. Seventy-one (67%) presented to the emergency department (ED) specifically for acute cholecystitis, and 35 (23%) were inpatients previously admitted for other conditions. Outcomes of the two groups were compared with respect to severity of illness, leukocytosis, bile culture, liver function tests, imaging features, time intervals from onset of symptoms to medical and percutaneous intervention, and whether surgical cholecystectomy was later performed. Overall, 72 patients (68%) showed an improvement clinically, whereas 34 (32%) showed no improvement or a clinically worsened condition after cholecystostomy. Patients who presented to the ED primarily with acute cholecystitis fared better (84% of patients showed improvement) than inpatients (34% showed improvement; P < .0001). Gallstones were identified in 54% of patients who presented to the ED, whereas acalculous cholecystitis was more commonly diagnosed in inpatients (54%). Patients with sepsis had worse outcomes overall (P < .0001). Bacterial bile cultures were analyzed in 95% of patients and showed positive results in 52%, with no overall effect on outcome. There was no correlation between the time of onset of symptoms until antibiotic therapy or cholecystostomy in either group. Long-term outcomes for both groups were better for those who later underwent cholecystectomy (P < .0001). Outcomes after percutaneous cholecystostomy for acute cholecystitis are better when the disease is primary and not precipitated by concurrent illness.
    No preview · Article · Nov 2011 · Journal of vascular and interventional radiology: JVIR
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    ABSTRACT: To perform embolization of parasitized extrahepatic arteries (EHAs) before radioembolization to reestablish intrahepatic arterial supply to large, peripheral tumors, and to evaluate the technical and clinical outcomes of this intervention. Among 201 patients retrospectively analyzed, embolization of 73 parasitized EHAs in 35 patients was performed. Most embolization procedures were performed during preparatory angiography using large particles and coils. Digital subtraction angiography (DSA), C-arm computed tomography (CT), and technetium-99m macroaggregated albumin ((99m)TcMAA) scintigraphy were used to evaluate the immediate perfusion via intrahepatic collateral channels of target tumor areas previously supplied by parasitized EHAs. Follow-up imaging of differential regional tumor response was used to evaluate microsphere distribution and clinical outcome. After embolization, reestablishment of intrahepatic arterial supply was confirmed by both DSA and C-arm CT in 94% of territories and by scintigraphy in 96%. In 32% of patients, the differential response of treatment could not be evaluated because of uniform disease progression. However, symmetric regional tumor response in 94% of evaluable patients indicated successful delivery of microspheres to the territories previously supplied by parasitized EHAs. Reestablishment of intrahepatic arterial inflow to hepatic tumors by embolization of parasitized EHAs is safe and effective and results in successful delivery of yttrium-90 microspheres to tumors previously perfused by parasitized EHAs.
    No preview · Article · Oct 2011 · Journal of vascular and interventional radiology: JVIR
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    ABSTRACT: Before yttrium-90 ((90)Y) radioembolization administration, the authors consolidated arterial inflow by embolizing variant hepatic arteries (HAs) to make microsphere delivery simpler and safer. The present study reviews the technical and clinical success of these consolidation procedures. Preparatory and treatment angiograms were retrospectively analyzed for 201 patients. Variant HAs were coil-embolized during preparatory angiography to simplify arterial anatomy. Collateral arterial perfusion of territories previously supplied by variant HAs was evaluated by digital subtraction angiography (DSA), C-arm computed tomography (CT), and technetium-99m ((99m)Tc)-macroaggregated albumin (MAA) scintigraphy, and by follow-up evaluation of regional tumor response. A total of 47 variant HAs were embolized in 43 patients. After embolization of variant HAs, cross-perfusion into the embolized territory was depicted by DSA and by C-arm CT in 100% of patients and by (99m)Tc-MAA scintigraphy in 92.7%. Uniform progressive disease prevented evaluation in 33% of patients, but regional tumor response in patients who responded supported successful delivery of microspheres to the embolized territories in 95.5% of evaluable patients. Embolization of variant HAs for consolidation of hepatic supply in preparation for (90)Y radioembolization promotes treatment of affected territories via intrahepatic collateral channels.
    No preview · Article · Oct 2011 · Journal of vascular and interventional radiology: JVIR
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    ABSTRACT: To prospectively evaluate the impact of C-arm CT on radiation exposure to hepatocellular carcinoma (HCC) patients treated by chemoembolization. Patients with HCC (N = 87) underwent digital subtraction angiography (DSA; control group) or combined C-arm CT/DSA (test group) for chemoembolization. Dose-area product (DAP) and cumulative dose (CD) were measured for guidance and treatment verification. Contrast agent volume and C-arm CT utility were also measured. The marginal DAP increase in the test group was offset by a substantial (50%) decrease in CD from DSA. Use of C-arm CT allowed reduction of DAP and CD from DSA imaging (P = .007 and P = .017). Experienced operators were more efficient in substituting C-arm CT for DSA, resulting in a negligible increase (7.5%) in total DAP for guidance, compared with an increase of 34% for all operators (P = .03). For treatment verification, DAP from C-arm CT exceeded that from DSA, approaching that of conventional CT. The test group used less contrast medium (P = .001), and C-arm CT provided critical or supplemental information in 20% and 17% of patients, respectively. Routine use of C-arm CT can increase stochastic risk (DAP) but decrease deterministic risk (CD) from DSA. However, the increase in DAP is operator-dependent, thus, with experience, it can be reduced to under 10%. C-arm CT provides information not provided by DSA in 33% of patients, while decreasing the use of iodinated contrast medium. As with all radiation-emitting modalities, C-arm CT should be used judiciously.
    No preview · Article · Aug 2011 · Journal of vascular and interventional radiology: JVIR
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    ABSTRACT: Patients with autogenous native vessel portosystemic shunts, whether surgical or congenital, may experience complications of excess shunt flow, including hepatopulmonary syndrome (HPS), hepatic encephalopathy (HE), and hepatic insufficiency. The authors explored endovascular reduction or occlusion of autogenous portosystemic shunts using methods commonly employed in transjugular intrahepatic portosystemic shunt (TIPS) reduction in four pediatric patients. Before treatment, the patients had hypoplastic, atrophic, or thrombosed portal veins. Following intervention, symptoms of overshunting resolved or improved in all patients without major complications. The innate plasticity of the pediatric portal venous system allowed for hypertrophy or development and maturation of cavernous transformations to accommodate increased hepatopetal blood flow and pressure.
    No preview · Article · Aug 2011 · Journal of vascular and interventional radiology: JVIR

Publication Stats

661 Citations
170.05 Total Impact Points

Institutions

  • 2007-2015
    • Stanford University
      • • Department of Radiology
      • • Division of Interventional Radiology
      Stanford, California, United States
  • 2014
    • University of Zaragoza
      Caesaraugusta, Aragon, Spain
  • 2012
    • Stanford Medicine
      • Division of Interventional Radiology
      Stanford, California, United States