Transrenal Ureteral Occlusion for Palliation of Refractory Urine Leaks Using Vascular Plugs and Liquid Ethylene Vinyl Alcohol.

PURPOSE: To describe outcomes of transrenal embolization with vascular plugs and ethylene vinyl alcohol (EVOH) in a case series of patients with refractory urinary leak or fistula. MATERIALS AND METHODS: Fifteen ureteral occlusions performed over 53 months in 9 consecutive patients (56% female; mean age 61 y; range, 45-80 y) were reviewed retrospectively. The main indication was palliation for refractory fistula or leak in the setting of malignancy not responding to urine diversion by percutaneous nephrostomy tube or nephroureteral stent. Transrenal ureteral occlusion was performed using EVOH injected between vascular plugs placed distal and proximal to the leak or fistula. RESULTS: Technical success was 100%. Considerable reduction of urine leak or symptoms (clinical success) was achieved in 64% of ureters after mean follow-up of 105 days (range, 0-632 d). Complete ureteral occlusion on follow-up anterograde nephrostogram (imaging success) was achieved in 60% of ureters after mean follow-up of 139 days (range, 0-643 d). One patient with distal ureterovesical junction-perineal fistula had continued leak despite complete proximal occlusion of ureter owing to retrograde urine reflux from the bladder and was treated with endoscopic injection of intramural calcium hydroxyapatite to the ureteral segment distal to the fistula. Three ureters (33%) in 2 patients with vesicovaginal fistula had recanalization, requiring additional proximal embolization, yielding secondary success rates of 91% (clinical) and 90% (imaging) per ureter. One minor urinary tract infection and no major complications occurred. CONCLUSIONS: Transrenal anterograde ureteral occlusion using EVOH between vascular plugs could be considered a relatively safe and potentially valuable treatment option for refractory ureteral fistulae.

Partial splenic embolisation using n-butyl cyanoacrylate: intraprocedural evaluation by magnetic resonance imaging.

OBJECTIVES: To evaluate the use of diffusion-weighted imaging (DWI) for estimating infarcted splenic volume during partial splenic embolisation (PSE) using n-butyl cyanoacrylate (NBCA). METHODS: Twenty consecutive patients (57.2 ± 11.7 years) with hypersplenism underwent PSE. Intrasplenic branches were embolised using NBCA via a 2.1-French microcatheter aiming at infarction of 50 to 80 % of total splenic volume. Immediately after PSE, signal intensities (SI) of embolised and non-embolised splenic parenchyma were measured on DWI. Semi-automated volumetry (SAV) on DWI was compared with conventional manual volumetry (MV) on contrast-enhanced CT 1 week after PSE. Platelet counts were recorded before and after PSE. RESULTS: The SI on DWI in the embolised parenchyma decreased significantly (P < 0.01) to 24.7 ± 8.1 % as compared to non-embolised parenchyma. SAV and MV showed a strong correlation (r = 0.913 before PSE, r = 0.935 after PSE, P < 0.01) and significant (P < 0.01) reduction of normal splenic volume was demonstrated on both SAV (71.9 ± 12.4 %) and MV (73.6 ± 9.3 %) after PSE. Based on the initial SAV, three patients (15 %) underwent additional branch embolisation to reach sufficient infarction volume. Platelet counts elevated significantly (522.8 ± 209.1 %, P < 0.01) by 2 weeks after PSE. No serious complication was observed. CONCLUSION: Immediate SI changes on DWI after PSE allowed semi-automated splenic volumetry on site. KEY POINTS: • Partial splenic embolisation (PSE) is an important interventional technique for hypersplenism • Diffusion-weighted MR reveals an immediate decrease in signal in the embolised parenchyma • Such signal reduction permits semi-automated splenic volumetry on site. • This allows precise quantification of the amount of parenchyma infarcted, avoiding additional PSE.

Carbon dioxide (CO2) vs iodinated contrast digital subtraction angiography during balloon-occluded retrograde transvenous obliteration (BRTO) using foam sclerosant for gastric varices.

PURPOSE: To compare the visualization of the target gastric varices (GV) on balloon-occluded retrograde transvenous venography (BRTV) using iodinated contrast material vs carbon dioxide (CO(2)) in preparation for subsequent balloon-occluded retrograde transvenous obliteration (BRTO) using foam sclerotherapy. MATERIALS AND METHODS: In 16 consecutive patients with nonruptured GV, BRTV was performed first using iodinated contrast material and then with CO(2). BRTV was repeated whenever there were changes in the catheter or patient position or when coil embolization of collaterals was needed. Each visualization grade of GV (grade 1 = GV only; grade 2 = GV > collaterals; 3 = GV < collaterals; grades 4-5 = collaterals only) was determined by two observers in consensus. During foam BRTO, the GV visualization grade was recorded again and confirmed by C-arm computed tomography (CT). RESULTS: In 38 pairs of BRTV, GV grades were significantly (P < .0001) lower (ie, favoring BRTO) on CO(2) BRTV (mean ± standard deviation, 1.8 ± 0.8) than on iodine BRTV (3.4 ± 0.8). GV grades on foam BRTO (1.4 ± 0.7) were similar to the grades obtained on the most recent CO(2) BRTV (1.3 ± 0.5) but were significantly smaller (P < .0001) than on iodinated BRTV (3.1 ± 0.9). GV were opacified by foam on initial C-arm CT in 14 patients (87.5%), and complete thrombosis of GV was obtained without any complication in all 16 patients (100%). CO(2) reached the GV even when iodinated contrast material could not (grade 4) in seven of our 16 patients (43.8%), leading to successful BRTO. CONCLUSIONS: CO(2) BRTV visualized GV better than did iodine BRTV and changed the management of more than 40% of patients by enabling successful foam BRTO in patients in which conventional liquid BRTO could not be performed.

Balloon-occluded retrograde transvenous obliteration of gastric varices: use of CT-guided foam sclerotherapy to optimize technique.

OBJECTIVE: Balloon-occluded retrograde transvenous obliteration has been traditionally based on liquid sclerotherapy. However, overdose and systemic spillage of liquid sclerosant can cause severe complications, such as hemolysis, which lead to hemoglobinuria, allergy, acute respiratory distress syndrome, and other disorders. The purpose of this study was to evaluate the performance of foam sclerotherapy with C-arm CT guidance to reduce the amount of sclerosant and to optimize the safety of balloon-occluded retrograde transvenous obliteration while preserving its efficacy. MATERIALS AND METHODS: Twenty consecutively registered patients with gastric varices underwent balloon-occluded retrograde transvenous obliteration with polidocanol foam. C-arm CT guidance was used to confirm gas filling of the target vessels. In this retrospective analysis of a prospectively encoded database, total net doses of polidocanol used for transvenous obliteration and of contrast medium used for venography before transvenous obliteration were compared, and subsequent complications, including hemoglobinuria, were documented. RESULTS: In all patients, foam was observed in the target vessels at C-arm CT. The mean dose of polidocanol used for balloon-occluded retrograde transvenous obliteration (3.9 ± 1.5 mL) was significantly smaller (p < 0.001) than the dose of contrast medium used for venography (16.4 ± 7.9 mL). Hemoglobinuria was found in only one patient. Except in one instance of recanalization, full variceal thrombosis was confirmed at contrast-enhanced CT 1 week after transvenous obliteration (success rate, 95%). In one patient, air migrated into the liver during transvenous obliteration but was spontaneously absorbed. No serious complication occurred. CONCLUSION: Balloon-occluded retrograde transvenous obliteration with polidocanol foam under C-arm CT guidance allowed significant reduction of sclerosant dose and resulted in a low complication rate while a high technical success rate and efficacy were maintained.

C-arm CT-guided foam sclerotherapy for the treatment of gastric varices.

The authors describe here the use of foam sclerotherapy under C-arm computed tomography (CT) guidance for the treatment of gastric varices via balloon-occluded retrograde transvenous obliteration in seven patients and percutaneous transhepatic obliteration in one patient. All gastric varices were occluded successfully after replacement of blood by foam, which was trapped in the gastric varices as shown by C-arm CT. It also helped reduce the amount of sclerosant, an issue that is associated with severe complications, such as hemolysis, allergy, acute respiratory distress syndrome, and others. Foam sclerotherapy under C-arm CT guidance is a promising tool in the therapeutic armamentarium against gastric varices.

Role of Interventional Radiology in the Management of Infection.

Interventional radiology (IR) is plays a crucial role in the management of localized infections, utilizing percutaneous access to loculated fluid collections for drainage and source control. Interventions have been developed in multiple organs and systems and used over decades, allowing the IR physician to provide patient care in many cases where surgical options are not optimal. In this review, we will examine the emergent, urgent, and routine nature of various IR procedures in the infectious context and timelines for each in regards to the decision making process. An algorithmic approach should guide the clinician's decision making for IR procedures in both large academic centers and smaller community hospitals. This approach and the pertinent procedural technique are described for multiple systems and organs including the biliary tree, gallbladder, genitourinary tract, and thoracic, abdominal, and pelvic abscesses. Increased awareness of the abilities and limitations of IR physicians in clinical scenarios needs to be implemented, to allow multispecialty input in efforts to decrease morbidity and mortality.

A systematic review on diagnostic accuracy of CT-based detection of significant coronary artery disease.

OBJECTIVES: Systematic review of diagnostic accuracy of contrast enhanced coronary computed tomography (CE-CCT). BACKGROUND: Noninvasive detection of coronary artery stenosis (CAS) by CE-CCT as an alternative to catheter-based coronary angiography (CCA) may improve patient management. METHODS: Forty-one articles published between 1997 and 2006 were included that evaluated native coronary arteries for significant stenosis and used CE-CCT as diagnostic test and CCA as reference standard. Study group characteristics, study methodology and diagnostic outcomes were extracted. Pooled summary sensitivity and specificity of CE-CCT were calculated using a random effects model (1) for all coronary segments, (2) assessable segments, and (3) per patient. RESULTS: The 41 studies totaled 2515 patients (75% males; mean age: 59 years, CAS prevalence: 59%). Analysis of all coronary segments yielded a sensitivity of 95% (80%, 89%, 86%, 98% for electron beam CT, 4/8-slice, 16-slice and 64-slice MDCT, respectively) for a specificity of 85% (77%, 84%, 95%, 91%). Analysis limited to segments deemed assessable by CT showed sensitivity of 96% (86%, 85%, 98%, 97%) for a specificity of 95% (90%, 96%, 96%, 96%). Per patient, sensitivity was 99% (90%, 97%, 99%, 98%) and specificity was 76% (59%, 81%, 83%, 92%). Heterogeneity was quantitatively important but not explainable by patient group characteristics or study methodology. CONCLUSIONS: Current diagnostic accuracy of CE-CCT is high. Advances in CT technology have resulted in increases in diagnostic accuracy and proportion of assessable coronary segments. However, per patient, accuracy may be lower and CT may have more limited clinical utility in populations at high risk for CAD.

Screening carotid sonography before elective coronary artery bypass graft surgery: who needs it.

OBJECTIVE: The purpose of this study was to determine whether selection criteria for performing carotid sonographic screening before elective coronary artery bypass graft surgery can decrease the number of negative examinations without overlooking patients with significant carotid disease. SUBJECTS AND METHODS: A history of peripheral vascular disease, a prior cerebrovascular event, smoking, diabetes, hypertension, cervical carotid disease, left main coronary disease, and patient sex were criteria prospectively gathered for 295 consecutive patients undergoing screening carotid sonography before elective coronary artery bypass surgery. Logistic regression modeling was used to determine if any single criterion or combination of criteria could be applied to decrease the number of screening examinations without sacrificing detection of significant (> or = 50% cross-sectional narrowing) carotid stenosis. RESULTS: Smoking, diabetes, hypertension, a previous cerebrovascular event, peripheral vascular disease, left main coronary artery disease, and a history of cervical carotid disease were associated with significant carotid disease (chi-square test) in our subject population. Logistic modeling showed that the probability of detecting significant carotid disease increases 2.98 times for each additional selection criterion present. Possessing at least one selection criterion would still yield 100% examination sensitivity while increasing specificity to 30.0%. CONCLUSION: Selection criteria should be applied when choosing patients for carotid sonographic screening before elective coronary artery bypass surgery. This approach would decrease the number of noncontributory examinations but would have little effect on the detection of significant carotid stenosis in this target population.

Establishing an outpatient clinic for minimally invasive vein care.

OBJECTIVE: Minimally invasive vein care procedures are less invasive than surgery and have a lower complication rate, are well tolerated by patients, and have good cosmetic results. Because radiologists have expertise in imaging-guided procedures, offering minimally invasive vein care is a logical step. CONCLUSION: Starting an effective outpatient vein care clinic involves decisions about space, equipment, and advertising. With proper staffing and rapport with patients and referring physicians, a varicose vein practice can be a profitable adjunct to any radiology practice.

The effect of hyperoxygenation on T1 relaxation time in vitro.

RATIONALE AND OBJECTIVES: Ventilation with high oxygen (O2) concentrations has been shown to decrease T1 in blood and tissues of patients. This study aims to assess the effect of hyperoxygenation on the T1 relaxation time of blood and other physiologic solutions. MATERIALS AND METHODS: Varied gaseous mixtures of O2 and air between 21% and 100% O2 were created using an experimental circuit at room temperature, and used to saturate human blood, plasma, or normal saline. The samples were studied using an 8.45-Tesla magnetic resonance (MR) system and a 1.5-Tesla clinical MR scanner. RESULTS: MR spectroscopy at 8.45 Tesla showed that the percentage of O2 chosen for saturation correlated negatively with T1 (R2 = 1.00 for blood, 0.99 for plasma, and 1.00 for normal saline). The reduction in T1 between solutions saturated with 21% and 100% O2 was 487 milliseconds (22% of the baseline T1 value) for blood, 391 milliseconds (15%) for plasma and 622 milliseconds (19%) for saline. Similarly, MR measurements at 1.5 Tesla showed T1 reduction with increasing O2 concentration. Conclusion. The decreasing T1 in blood depends strongly on the fraction of dissolved O2 in solution and is largely independent of the hemoglobin content.

Comparison of clinical and MR imaging outcomes after uterine fibroid embolization with Bead Block and Embosphere.

PURPOSE: To compare clinical and imaging outcomes after uterine fibroid embolization (UFE) with Embosphere versus Bead Block microspheres. MATERIALS AND METHODS: Our institutional review board approved this HIPAA-compliant study. We conducted a retrospective review of all consecutive UFEs performed for symptomatic uterine fibroids at our academic institution from 2001 to 2008. UFE was performed using Embosphere (n = 70) or Bead Block (n = 55) microspheres. Patient symptoms and MR images were reviewed before and following UFE. The MR images were analyzed for changes in the size and contrast enhancement of the dominant fibroid and the uterus. RESULTS: 125 patients underwent UFE. Pre-treatment characteristics (patient age, presenting symptoms, fibroid location, and volume of the largest fibroid) were similar across groups. Procedure endpoint (near-stasis, reached in 94% of cases), duration, and sedation medication doses were also similar. Clinical follow-up was available in 69 (55%) patients (mean duration: 13.6 months). Of these, 92% had clinical improvement of their main presenting symptom(s) and 3% developed early menopause. MRI follow-up was available in 105 (84%) patients (mean 7.8 months). Mean volume reduction of the largest fibroid was similar after Embosphere (48%) and Bead Block (53%, p = NS). Residual enhancement ≥ 5% in the dominant fibroid was similarly uncommon after Bead Block (19%) or Embosphere (16%, p = NS). Mean uterine volume reduction was similar across groups (38%); no myometrial infarction occurred. CONCLUSION: This retrospective study showed no superiority of Embosphere over Bead Block microspheres in terms of clinical and imaging outcomes after UFE.

Endovenous laser ablation of the small saphenous vein sparing the saphenopopliteal junction.

To assess outcomes after endovenous laser ablation (EVLA) of the small saphenous vein (SSV). Retrospective review was performed of all consecutive EVLA procedures performed over a 39-month period at three neighboring vein practices for symptomatic, duplex ultrasound-proven incompetence of the SSV. EVLA was performed under ultrasound guidance with an 810- or 980-nm diode laser in continuous mode using the pullback method while sparing the deep, most cephalad segment of the SSV near the saphenopopliteal junction. Follow-up after EVLA included patient symptoms, physical examination, and duplex ultrasound. Pretreatment variables were similar across all three practices. EVLA was performed to treat 67 incompetent SSVs in 63 patients (86% women; mean age and 95% confidence interval, 50 +/- 3 years; range, 20-82 years). Average energy delivered was 92 J/cm. Immediate technical success and occlusion of the treated vein at 1-2 weeks was 100%. Imaging follow-up length was 243 +/- 65 days (range, 3-893 days). Clinical follow-up (243 +/- 66 days) showed symptomatic improvement in 66 (99%) of 67 patients; one patient had recanalization with recurrent reflux by ultrasound (2%). Complications included one case of paresthesias lasting beyond 1 month of follow-up (2%) and three cases of superficial phlebitis (4%), but no deep vein thrombosis, skin burns, or other complications. Although ablation involved only the superficial portion of the SSV and spared its deep segment in the popliteal fossa, SSV occlusion typically extended up to the saphenopopliteal junction or to a gastrocnemial collateral, without popliteal vein involvement. EVLA of the SSV is safe and effective when the saphenopopliteal junction and popliteal fossa are avoided. This approach may help reduce the risk of paresthesias or other complications while maintaining low recanalization rates.