Management of Severe Bleeding in Patients Treated With Oral Anticoagulants: Proceedings Monograph From the Emergency Medicine Cardiac Research and Education Group-International Multidisciplinary Severe Bleeding Consensus Panel October 20, 2018.

In this Emergency Medicine Cardiac Research and Education Group (EMCREG)-International Proceedings Monograph from the October 20, 2018, EMCREG-International Multidisciplinary Consensus Panel on Management of Severe Bleeding in Patients Treated With Oral Anticoagulants held in Orlando, FL, you will find a detailed discussion regarding the treatment of patients requiring anticoagulation and the reversal of anticoagulation for patients with severe bleeding. For emergency physicians, critical care physicians, hospitalists, cardiologists, internists, surgeons, and family physicians, the current approach and disease indications for treatment with anticoagulants such as coumadin, factor IIa, and factor Xa inhibitors are particularly relevant. When a patient treated with anticoagulants presents to the emergency department, intensive care unit, or operating room with severe, uncontrollable bleeding, achieving rapid, controlled hemostasis is critically important to save the patient's life. This EMCREG-International Proceedings Monograph contains multiple sections reflecting critical input from experts in Emergency Cardiovascular Care, Prehospital Emergency Medical Services, Emergency Medicine Operations, Hematology, Hospital Medicine, Neurocritical Care, Cardiovascular Critical Care, Cardiac Electrophysiology, Cardiology, Trauma and Acute Care Surgery, and Pharmacy. The first section provides a description of the current indications for the treatment of patients using oral anticoagulants including coumadin, the factor IIa (thrombin) inhibitor dabigatran, and factor Xa inhibitors such as apixaban and rivaroxaban. In the remaining sections, the treatment of patients presenting to the hospital with major bleeding becomes the focus. The replacement of blood components including red blood cells, platelets, and clotting factors is the critically important initial treatment for these individuals. Reversing the anticoagulated state is also necessary. For patients treated with coumadin, infusion of vitamin K helps to initiate the process of protein synthesis for the vitamin K-dependent coagulation proteins II, VII, IX, and X and the antithrombotic protein C and protein S. Repletion of clotting factors for the patient with 4-factor prothrombin complex concentrate, which includes factors II (prothrombin), VII, IX, and X and therapeutically effective concentrations of the regulatory proteins (protein C and S), provides real-time ability to slow bleeding. For patients treated with the thrombin inhibitor dabigatran, treatment using the highly specific, antibody-derived idarucizumab has been demonstrated to reverse the hypocoagulable state of the patient to allow blood clotting. In May 2018, andexanet alfa was approved by the US Food and Drug Administration to reverse the factor Xa anticoagulants apixaban and rivaroxaban in patients with major bleeding. Before the availability of this highly specific agent, therapy for patients treated with factor Xa inhibitors presenting with severe bleeding usually included replacement of lost blood components including red blood cells, platelets, and clotting factors and 4-factor prothrombin complex concentrate, or if not available, fresh frozen plasma. The evaluation and treatment of the patient with severe bleeding as a complication of oral anticoagulant therapy are discussed from the viewpoint of the emergency physician, neurocritical and cardiovascular critical care intensivist, hematologist, trauma and acute care surgeon, hospitalist, cardiologist, electrophysiologist, and pharmacist in an approach we hope that the reader will find extremely practical and clinically useful. The clinician learner will also find the discussion of the resumption of oral anticoagulation for the patient with severe bleeding after effective treatment important because returning the patient to an anticoagulated state as soon as feasible and safe prevents thrombotic complications. Finally, an EMCREG-International Severe Bleeding Consensus Panel algorithm for the approach to management of patients with life-threatening oral anticoagulant-associated bleeding is provided for the clinician and can be expanded in size for use in a treatment area such as the emergency department or critical care unit.

Augmented Reality on a C-Arm System: A Preclinical Assessment for Percutaneous Needle Localization.

Purpose To compare the navigational accuracy and radiation dose during needle localization of targets for augmented reality (AR) with and without motion compensation (MC) versus those for cone-beam computed tomography (CT) with real-time fluoroscopy navigation in a pig model. Materials and Methods This study was approved by the Institutional Animal Care and Use Committee. Three operators each localized 15 targets (bone fragments) approximately 7 cm deep in the paraspinal muscles of nine Yorkshire pigs by using each of the three modalities (AR with and without MC and cone-beam CT with fluoroscopy). Target depth, accuracy (distance between needle tip and target), and radiation dose (dose-area product [DAP]) were recorded for each procedure. Correlation between accuracy and depth of target was assessed by using the Pearson correlation coefficient. Two-way analysis of variance was used for differentiating accuracy and DAPs across navigation techniques and operator backgrounds. Results There was no correlation between depth of target and accuracy. There was no significant difference in accuracy between modalities (mean distance, 3.0 mm ± 1.9 [standard deviation] for cone-beam CT with fluoroscopy, 2.5 mm ± 2.0 for AR, and 3.2 mm ± 2.7 for AR with MC [P = .33]). There was, however, a significant difference in fluoroscopy radiation dose (10.4 Gy · cm(2) ± 10.6 for cone-beam CT fluoroscopy, 2.3 Gy · cm(2) ± 2.4 for AR, and 3.3 Gy · cm(2) ± 4.6 for AR with MC [P < .05]) and therefore in total procedural radiation dose (20.5 Gy · cm(2) ± 13.4 for cone-beam CT fluoroscopy, 12.6 Gy · cm(2) ± 5.3 for AR, 13.6 Gy · cm(2) ± 7.4 for AR with MC [P < .05]). Conclusion Use of an AR C-arm system reduces radiation dose while maintaining navigational accuracy compared with cone-beam CT fluoroscopy during image-guided percutaneous needle placement in a pig model. (©) RSNA, 2016 Online supplemental material is available for this article.

Real-Time In Vivo Characterization of Primary Liver Tumors With Diffuse Optical Spectroscopy During Percutaneous Needle Interventions: Feasibility Study in Woodchucks.

OBJECTIVE: This study presents the first in vivo real-time optical tissue characterization during image-guided percutaneous intervention using near-infrared diffuse optical spectroscopy sensing at the tip of a needle. The goal of this study was to indicate transition boundaries from healthy tissue to tumors, namely, hepatic carcinoma, based on the real-time feedback derived from the optical measurements. MATERIALS AND METHODS: Five woodchucks with hepatic carcinoma were used for this study. The woodchucks were imaged with contrast-enhanced cone beam computed tomography with a flat panel detector C-arm system to visualize the carcinoma in the liver. In each animal, 3 insertions were performed, starting from the skin surface toward the hepatic carcinoma under image guidance. In 2 woodchucks, each end point of the insertion was confirmed with pathologic examination of a biopsy sample. While advancing the needle in the animals under image guidance such as fluoroscopy overlaid with cone beam computed tomography slice and ultrasound, optical spectra were acquired at the distal end of the needles. Optical tissue characterization was determined by translating the acquired optical spectra into clinical parameters such as blood, water, lipid, and bile fractions; tissue oxygenation levels; and scattering amplitude related to tissue density. The Kruskal-Wallis test was used to study the difference in the derived clinical parameters from the measurements performed within the healthy tissue and the hepatic carcinoma. Kurtoses were calculated to assess the dispersion of these parameters within the healthy and carcinoma tissues. RESULTS: Blood and lipid volume fractions as well as tissue oxygenation and reduced scattering amplitude showed to be significantly different between the healthy part of the liver and the hepatic carcinoma (P < 0.05) being higher in normal liver tissue. A decrease in blood and lipid volume fractions and tissue oxygenation as well as an increase in scattering amplitude were observed when the tip of the needle crossed the margin from the healthy liver tissue to the carcinoma. The kurtosis for each derived clinical parameter was high in the hepatic tumor as compared with that in the healthy liver indicating intracarcinoma variability. CONCLUSIONS: Tissue blood content, oxygenation level, lipid content, and tissue density all showed significant differences when the needle tip was guided from the healthy tissue to the carcinoma and can therefore be used to identify tissue boundaries during percutaneous image-guided interventions.

Clinically useful dilution factors for iodine and gadolinium contrast material: an animal model of pediatric digital subtraction angiography using state-of-the-art flat-panel detectors.

BACKGROUND: Iodinated and gadolinium contrast agents pose some risk for certain pediatric patients, including allergic-like reactions, contrast-induced nephropathy (CIN) and nephrogenic systemic fibrosis (NSF). Digital flat-panel detectors enhance image quality during angiography and might allow use of more dilute contrast material to decrease risk of complications that might be dose-dependent, such as CIN and NSF. OBJECTIVE: To assess the maximum dilution factors for iodine- and gadolinium-based contrast agents suitable for vascular imaging with fluoroscopy and digital subtraction angiography (DSA) on digital flat-panel detectors in an animal model. MATERIALS AND METHODS: We performed selective catheterization of the abdominal aorta, renal artery and common carotid artery on a rabbit. In each vessel we performed fluoroscopy and DSA during contrast material injection using iodinated and gadolinium contrast material at 100%, 80%, 50%, 33% and 20% dilutions. An image quality score (0 to 3) was assigned by each of eight evaluators. Intracorrelation coefficient, paired t-test, one-way repeated analysis of variance, Spearman correlation and receiver operating characteristic curve analysis were applied to the data. RESULTS: Overall the image quality scores correlated linearly with dilution levels. For iodinated contrast material, the optimum cut-off level for DSA when a score of at least 2 is acceptable is above 33%; it is above 50% when a score of 3 is necessary. For gadolinium contrast material, the optimum cut-off for DSA images is above 50% when a score of at least 2 is acceptable and above 80% when a score of 3 is necessary. CONCLUSION: Knowledge of the relationship between image quality and contrast material dilution might allow a decrease in overall contrast load while maintaining appropriate image quality when using digital flat-panel detectors.

Intrathyroidal thymic tissue mimicking a thyroid nodule in a 4-year-old child.

A 4 year-old girl was referred for CT of her neck for suspected submental lymphadenopathy and was found to have an incidental low-attenuation thyroid mass. Subsequent thyroid ultrasound showed a heterogeneous thyroid mass with punctate areas of increased echogenicity. Cytologic examination was consistent with ectopic intrathyroidal thymic nodule. We review the presentation of ectopic thymic tissue, especially in the thyroid gland.

Varicocele retrograde embolization with boiling contrast medium and gelatin sponges in adolescent subjects: a clinically effective therapeutic alternative.

PURPOSE: Varicoceles occur in approximately 15% of adolescent male subjects and may impair future fertility. The present study describes a varicocele treatment technique involving percutaneous retrograde embolization with boiling hot contrast medium and gelatin sponge pledgets. MATERIALS AND METHODS: A retrospective review of medical records and imaging of all patients who underwent percutaneous retrograde varicocele embolization from 2005 to 2010 was performed. Pre- and postembolization symptoms, physical findings, and ultrasound findings were documented. Fifteen patients (16 embolizations) were identified, with an average age of 15.9 years (range, 12-18 y). Nine were referred because of persistent varicocele after surgical ligation. Three had grade 2 and nine had grade 3 varicoceles. Two had grade 1 varicoceles; one was painful and one was associated with poor semen quality. One varicocele was not clinically evident, but was associated with persistently decreased testicular size. Nine patients had pain or discomfort, and six had no discomfort. Clinical resolution was defined by a combination of symptom resolution and a lack of physical examination findings of varicocele or findings of treated varicocele. RESULTS: Fifteen of the 16 embolizations (94%) were technically successful. Clinical resolution was documented in 14 of 15 patients (95%); one patient experienced a recurrence at 30 months, which was successfully reembolized. One patient experienced temporary paresthesia of the left thigh. There were no major postprocedural complications. Mean follow-up duration was 11 months. CONCLUSIONS: Retrograde embolization of varicoceles in adolescent subjects with the use of boiling hot contrast medium and gelatin sponges is a promising technique that appears effective.

Complex cloacal malformations: use of rotational fluoroscopy and 3-D reconstruction in diagnosis and surgical planning.

A cloacal malformation is a congenital malformation in which the urinary tract, gynecological system and distal rectum fail to separate and form a common channel with a single perineal opening. Precise anatomical information is required to plan surgery and predict prognosis for children with this abnormality. Conventional fluoroscopic studies provide limited information, primarily due to the overlap of structures and inability to make accurate measurements. Rotational fluoroscopy and 3-D reconstruction help clarify overlapping structures and allow for precise measurement of the common channel, thereby helping to predict the complexity of the surgical case as well as the long-term prognosis regarding bowel, bladder and sexual function.

Comparison of standard, prone and cine MRI in the evaluation of tethered cord.

BACKGROUND: Tethered cord syndrome (TCS) is defined by abnormal traction on the spinal cord that confines its movement. Surgical cord release usually stops neurological deterioration; therefore, early and accurate neuroradiological diagnosis is important. Supine MRI is the imaging modality of choice, but prone MRI and cine MRI can demonstrate cord movement. OBJECTIVE: We compared the diagnostic accuracies of standard MRI, prone MRI and cine MRI in patients with clinical suspicion of TCS and evaluated inter-reader reliability for MR imaging. MATERIALS AND METHODS: Children who underwent MRI for suspicion of TCS were retrospectively identified. Supine, prone and cine MRI studies were re-read by two pediatric neuroradiologists. Conus level, filum appearance and cord movement were documented. RESULTS: Thirteen of 49 children had tethered cord documented at surgery. Conus level had the highest diagnostic accuracy (sensitivity 69-77%, specificity 94%, positive predictive value 82-83%, negative predictive value 89-92%, correct diagnosis 88-90%) and highest between-reader concordance (98%). Prone and cine MRI did not add to the accuracy of the supine imaging. CONCLUSION: Conus level provides the highest diagnostic accuracy and inter-reader reliability in TCS. Until a larger series is evaluated, it remains questionable whether prone or cine MRI provides enough additional diagnostic information to warrant routine use.

Use of an Amplatz dilator to facilitate transrectal abscess drainage in children.

Image-guided transrectal drainage is an effective treatment option for many deep pelvic abscesses in children. Currently, a variety of imaging and catheter techniques are used to access and drain these abscesses. The present report describes an approach for introducing the transrectal catheter by using transabdominal ultrasound guidance to direct transrectal advancement of an Amplatz dilator with coaxial placement of the metal cannula and inner trocar from a pigtail catheter set, followed by placement of the pigtail catheter via Seldinger technique. This approach eliminates some of the limitations of other transrectal techniques. The present report describes a single-institutional experience with this technique in 13 patients.

Cardiovascular anomalies in Turner syndrome: spectrum, prevalence, and cardiac MRI findings in a pediatric and young adult population.

OBJECTIVE: Turner syndrome affects one in 2,500 girls and women and is associated with cardiovascular anomalies. Visualizing the descending thoracic aorta in adults with Turner syndrome with echocardiography is difficult. Therefore, cardiac MRI is the preferred imaging modality for surveillance. Our goals were to use cardiac MRI describe the spectrum and frequency of cardiovascular abnormalities and to evaluate aortic dilatation and associated abnormalities in pediatric patients with Turner syndrome. MATERIALS AND METHODS: The cases of 51 patients with Turner syndrome (median age, 18.4 years; range, 6-36 years) were evaluated with cardiac MRI. The characteristics assessed included aortic structure, elongation of the transverse aortic arch, aortic diameter at multiple locations, and coarctation of the aorta (CoA). Additional evaluations were made for presence of bicuspid aortic valve (BAV), and partial anomalous pulmonary venous return (PAPVR). Associations between the cardiac MRI data and the following factors were assessed: age, karyotype, body surface area, blood pressure, and ventricular sizes and function. RESULTS: Sixteen patients (31.4%) had elongation of the transverse aortic arch, eight (15.7%) had CoA, 20 (39.2%) had BAV, and eight (15.7%) had PAPVR. Aortic dilatation was most common at the aortic sinus (30%). Elongation of the transverse aortic arch was associated with CoA (p < 0.01) and BAV (p < 0.05). Patients with elongation of the transverse aortic arch had dilated aortic sinus (p < 0.05). Patients with PAPVR had increased right heart mass (p < 0.05), increased ratio of main pulmonary artery to aortic valve blood flow (p = 0.0014), and increased right ventricular volume (p < 0.05). CONCLUSION: Cardiovascular anomalies in pediatric patients with Turner syndrome include aortic abnormalities and PAPVR. The significant association between elongation of the transverse aortic arch and CoA, BAV, and aortic sinus dilatation may contribute to increased risk of aortic dissection. The presence of PAPVR can be hemodynamically significant. These findings indicate that periodic cardiac MRI screening of persons with Turner syndrome is beneficial.

Subcutaneous epidermal inclusion cysts: ultrasound (US) and MR imaging findings.

OBJECTIVE: To describe the characteristic US and MR findings of subcutaneous epidermal inclusion cysts. MATERIALS AND METHODS: Seventy-nine patients with subcutaneous epidermal inclusion cysts underwent US (n = 70), MR (n = 7), or both (n = 2). On US, the margin, shape, echogenicity, through-transmission, wall, internal debris and vascularity were evaluated. On MR, the shape, wall, signal intensity, internal debris, and enhancement pattern were evaluated. RESULTS: On US, characteristic findings were well circumscribed (n = 69, 96%), ovoid-shaped (n = 56, 78%), heterogeneously and mildly echogenic (n = 66, 92%), increased through-transmission (n = 66, 92%) and low echoic rim (n = 48, 67%). Internal debris was seen in 31 cases (43%) and often contained linear echogenic reflections (n = 12, 17%), dark clefts (n = 13, 18%), or a mixture (n = 5, 7%). Most masses showed no Doppler flow (n = 70, 97%). On MR, all cases demonstrated a well-demarcated oval-shaped mass with a surrounding rim. On T1-weighted image (WI), the mass showed slightly high T1 signal in 4/9 (44%) and iso-signal in 5/9 (56%). On T2WI, the mass showed high signal in 6/9 (67%), intermediate in 2/9 (22%), and a target appearance in 1/9 (11%). Internal linear dark T2 signal debris was observed in 4/9 (44%). All lesions showed peripheral rim enhancement without central enhancement. CONCLUSIONS: On US, subcutaneous epidermal inclusion cysts are usually well-circumscribed, oval-shaped, mildly echogenic masses with occasional linear anechoic and/or echogenic reflections, increased through-transmission, hypoechoic rim and no Doppler flow. On MR, an intermediate to high T2 signal mass with occasional low signal debris and no central enhancement can strengthen the diagnosis.

T2 relaxation time changes in distal femoral articular cartilage in children with juvenile idiopathic arthritis: a 3-year longitudinal study.

OBJECTIVE: Increased cartilage T2 relaxation time is thought to be an early marker of disease progression in juvenile idiopathic arthritis, because it can identify microstructural changes before damage becomes visible. The purpose of this study was to investigate longitudinal changes in T2 relaxation time mapping (i.e., T2 map) in children with early juvenile idiopathic arthritis and to compare with changes in clinical assessments. SUBJECTS AND METHODS: Twenty children (age range, 6.4-16 years) with early juvenile idiopathic arthritis completed at least four evaluations with T2 maps and clinical assessments: at enrollment, at 3 months, and at 1, 2, and 3 years. Sagittal T2 maps of distal femoral cartilage were generated, a region of interest was selected, and a T2 relaxation time profile was generated. The area under the curve from the T2 profile (i.e., T2 value) was correlated with patient age and sex and the following clinical assessments: total knee score, Childhood Health Assessment Questionnaire, physician global assessment, parent global assessment, and total number of active joints. RESULTS: There was a significant increase in mean T2 values from 3 months to 2 years (p < 0.05). There was a significant decrease in mean Childhood Health Assessment Questionnaire values between enrollment and 2 years (p < 0.05) and a significant decrease in parent global assessment, physician global assessment, total number of active joints, and total knee score values between enrollment and 1 year (p < 0.05). There were no statistically significant correlations between T2 values and patient age, sex, or clinical assessments. CONCLUSION: In patients with early juvenile idiopathic arthritis, T2 maps showed increased T2 values from the 3-month to 2-year follow-up, during which time the clinical assessments improved. This increase likely represents progressive microstructural changes, even though clinical symptoms improved with treatment.

T2 mapping in Duchenne muscular dystrophy: distribution of disease activity and correlation with clinical assessments.

PURPOSE: To analyze T2 maps of pelvic and thigh muscles in Duchenne muscular dystrophy (DMD), to identify the most severely affected muscle, and to correlate the T2 of muscle with the grade of fatty infiltration at nonquantitative magnetic resonance (MR) imaging and results of clinical assessment. MATERIALS AND METHODS: This prospective study was HIPAA compliant and was approved by the institutional review board; written consent was obtained from all participants' parents or guardians. Thirty-four boys with DMD (mean age, 8.4 years) were evaluated clinically (age, clinical function score, timed Gower score, time to run 30 feet, and serum creatine kinase [CK] level) and with nonquantitative MR imaging and axial T2 mapping from the iliac crest to the mid thigh. The T2 maps and mean T2 of 18 muscles in the pelvis and thighs were analyzed to identify the most severely involved muscle. The amount of fatty infiltration was assigned a grade of zero to four for all pelvic and thigh muscles by using T1-weighted nonquantitative MR images. The Spearman correlation coefficients model was used to correlate the mean T2, nonquantitative MR imaging score and clinical assessments. RESULTS: The gluteus maximus muscle had the highest T2. The mean T2 for this muscle showed a significant correlation with the nonquantitative MR imaging score for fatty infiltration (P < .001) and with all clinical assessments except CK level. CONCLUSION: Gluteus maximus muscles are most severely affected in patients with DMD. The T2 of the gluteus maximus muscle can be used as a quantitative and objective measure of disease severity.

Image gently: a web-based practice quality improvement program in CT safety for children.

OBJECTIVE: Radiologists want to improve quality and safety to benefit their pediatric patients and to comply with new requirements of the American Board of Radiology for maintenance of certification. The purpose for this article is to describe the development, construction, and content of a free, Web-based practice quality improvement (PQI) module in CT safety for children. CONCLUSION: We describe an online tutorial accessible on the Image Gently Website that enables radiologists nationwide to perform PQI in CT safety for pediatric patients.

MR imaging assessment of the lateral head of the gastrocnemius muscle: prevalence of segmental anomalous origins in children and young adults.

BACKGROUND: Variations in the lower extremity musculature have been identified, including an anomalous origin of the medial head of the gastrocnemius muscle. Anomalies of the lateral head of the gastrocnemius muscle (LGN) have been less frequently described, especially in children. OBJECTIVE: To describe the MR imaging appearance, frequency and clinical symptoms associated with anatomic variations of the LGN in children and young adults. MATERIALS AND METHODS: A retrospective review of 465 knee MR imaging examinations was performed. The site of origin of the LGN was identified as either normal, lateral segmental anomalous origin (LSAO), or medial accessory anomalous origin (MAAO). The clinical indication for imaging was recorded. RESULTS: An anatomic variation of the LGN was identified in 16 patients (3.4%). Nine patients had LSAO, and five of these had symptoms referable to or abnormalities of the patella. Seven patients had MAAO, and three of these had chronic nontraumatic knee pain. CONCLUSION: Anatomic variations of the LGN are not rare in young patients, occurring with a frequency of 3.4% in our series. It is unknown whether these anomalies play a role in the etiology of patellofemoral pain or unexplained joint pain in children.

Efficacy of a radiation safety education initiative in reducing radiation exposure in the pediatric IR suite.

BACKGROUND: The use of ionizing radiation is essential for diagnostic and therapeutic imaging in the interventional radiology (IR) suite. As the complexity of procedures increases, radiation exposure risk increases. We believed that reinforcing staff education and awareness would help optimize radiation safety. OBJECTIVE: To evaluate the effect of a radiation safety education initiative on IR staff radiation safety practices and patient radiation exposure. MATERIALS AND METHODS: After each fluoroscopic procedure performed in the IR suite during a 4-month period, dose-area product (DAP), fluoroscopy time, and use of shielding equipment (leaded eyeglasses and hanging lead shield) by IR physicians were recorded. A lecture and article were then given to IR physicians and technologists that reviewed ALARA principles for optimizing radiation dose. During the following 4 months, those same parameters were recorded after each procedure. RESULTS: Before education 432 procedures were performed and after education 616 procedures were performed. Physician use of leaded eyeglasses and hanging shield increased significantly after education. DAP and fluoroscopy time decreased significantly for uncomplicated peripherally inserted central catheters (PICC) procedures and non-PICC procedures after education, but did not change for complicated PICC procedures. CONCLUSION: Staff radiation safety education can improve IR radiation safety practices and thus decrease exposure to radiation of both staff and patients.

Live 3D guidance in the interventional radiology suite.

OBJECTIVE: The development of a C-arm cone-beam CT unit coupled with flat detectors has markedly increased anatomic visualization capabilities for interventional radiology procedures. We present technology in which fluoroscopy and 3D imaging from a cone-beam CT-flat-detector C-arm unit are combined with an integrated tracking and navigation system. A description of the technology and representative clinical cases are presented. CONCLUSION: This new combination further increases interventional radiologic capabilities because it provides real-time procedural evaluation and tracking.

Embolization of an arterioportal fistula by injection of D-stat into the portal venous outflow.

Arterioportal fistulas may occur in liver transplant recipients after percutaneous biopsy. This report describes a case in which a 13-year-old liver transplant patient developed an arterioportal fistula after multiple liver biopsies and underwent coil embolization; however, at that time, there were at least two small arterial feeders that were not amenable to subselection. He later developed recurrent variceal bleeding, and repeat angiogram revealed multiple tiny serpentine feeding arteries. Because these arteries could not be subselectively catheterized, the collagen-thrombin mixture, D-Stat, was used to occlude the portal venous outflow of the arterioportal fistula. Subsequent angiography demonstrated successful complete occlusion of the arterioportal fistula.