Surgical resection criteria and neoadjuvant therapies for intrahepatic cholangiocarcinoma.

The staging of intrahepatic cholangiocarcinoma (ICC) is complex, and there is no consensus among international cancer groups on how to most appropriately select candidates with nonmetastatic disease for surgical resection. Factors contributing to a higher stage of disease include larger tumor size, multiple tumors, vascular invasion (either portal venous or arterial), biliary invasion, involvement of local hepatic structures, serosal invasion, and regional lymph node metastases. For patients selected to undergo surgery, it is well-documented that R0 resection translates to a survival benefit. Estimating the risk of post-hepatectomy liver failure and post-surgical residual liver function is vital and may preclude some patients with significant tumor burden from undergoing surgery. Numerous serum and biliary biomarkers of the disease can help detect recurrence in patients undergoing surgical resection. Systemic and locoregional neoadjuvant treatments to facilitate better surgical outcomes have yielded mixed results regarding improving resectability and overall survival. Additional research is needed to identify optimal neoadjuvant treatment approaches and to evaluate which patients will benefit most from these strategies. Therapies targeting genetic mutations and protein aberrations found by tumor molecular profiling may offer additional options for future neoadjuvant treatment.

An Unsuccessful Randomized Trial of Percutaneous vs Endoscopic Drainage of Suspected Malignant Hilar Obstruction.

Percutaneous transhepatic biliary drainage (PTBD) and endoscopic retrograde cholangiopancreatography (ERCP) are widely accepted but competing approaches for the management of malignant obstruction at the hilum of the liver. ERCP is favored in the United States on the basis of high success rates for non-hilar indications, the perceived safety and superior tissue sampling capability of ERCP relative to PTBD, and the avoidance of external drains that are undesirable to patients. A recent randomized controlled trial (RCT) comparing the 2 modalities in patients with resectable hilar cholangiocarcinoma was terminated prematurely because of higher mortality in the PTBD group.1 In contrast, most observational data suggest that PTBD is superior for achieving complete drainage.2-6 Because the preferred procedure remains uncertain, we aimed to compare PTBD and ERCP as the primary intervention in patients with cholestasis due to malignant hilar obstruction (MHO).

Association between Periprocedural Neutropenia and Early Infection-related Chest Port Removal.

Background Patients who require long-term central venous access can present for port placement with depressed immune function as a result of their treatment or disease process. At present, there is no consensus regarding whether neutropenia at the time of port placement confers a higher risk for early infection-related port removal. Purpose To compare the incidence of early infection-related chest port removal in adults when placed in neutropenic versus nonneutropenic patient groups. Materials and Methods This retrospective cohort study examined 2580 port placements in 1081 men (41.9%) and 1499 women (58.1%) at a single tertiary medical center between June 2007 and July 2017. Mean patient age ± standard deviation was 56 years ± 14 (range, 18-91 years). The electronic medical record was used to identify neutropenia (absolute neutrophil count <1500 cells/mm3) at the time of port placement and incidence of infection-related port removal. Electronic medical record follow-up was conducted for 30 days following port placement. End points were infection-related port removal or death related to port infection within 30 days. Statistical analysis compared the neutropenic (n = 159) and nonneutropenic (n = 2421) patient groups by using a χ2 test for categorical data and a Student t test for continuous variables, with a Fisher exact test to compare incidence of port removal and death related to port infection. Results Ports placed in patients with neutropenia had an infection-related removal rate of 3.8% (six of 159) versus 0.91% (22 of 2421) in patients without neutropenia (P = .003). Patients with neutropenia had a port infection-related death rate of 0.63% (one of 159) versus 0.12% (three of 2421) for patients without neutropenia (P = .22). Conclusion Neutropenia in adults at the time of implantable subcutaneous chest port placement was associated with a higher risk for early infection-related port removal. There was no difference in the incidence of death related to port infection in neutropenic or nonneutropenic populations. © RSNA, 2019 See also the editorial by Johnson in this issue.

Neutrophil/Lymphocyte Ratio Predicts Increased Risk of Immediate Progressive Disease following Chemoembolization of Hepatocellular Carcinoma.

PURPOSE: To demonstrate that patients with hepatocellular carcinoma (HCC) and elevated baseline neutrophil/lymphocyte ratio (NLR) have a significantly greater risk of progressive disease following initial transarterial chemoembolization. MATERIALS AND METHODS: A total of 190 HCC patients (149 male/41 female) treated with transarterial chemoembolization between July 2013 and July 2017 were reviewed. Mean patient age was 62. Child-Pugh grades were 132 A, 61 B, and 4 C. Tracked criteria included etiology of cirrhosis, tumor number, Barcelona Clinic Liver Cancer score, diameter of the largest 2 tumors, and presence of portal vein thrombosis. Complete blood count with differential before the procedure was used for NLR calculation. Follow-up imaging was performed 2 months after treatment. The modified response evaluation criteria in solid tumors were used to assess response. The association between baseline NLR and tumor response (ordinal modified response evaluation criteria in solid tumors categories) on 2-month follow-up imaging was evaluated using the proportional odds logistic regression model. RESULTS: A total of 194 patients (76.6%) patients had a preprocedural NLR <3.5, and 59 (23%) patients had a preprocedural NLR ≥3.5. There was a statistically significant association between baseline NLR and immediate progression on 2-month follow-up imaging (mean NLR 4.10, 2.76, 2.72, and 2.48 for progressive and stable disease and partial and complete response, respectively; odds ratio 2.1, P = .04). NLR (P = .021) and tumor multiplicity (P = .011) predicted progressive disease at 2-month imaging. CONCLUSIONS: Elevated baseline NLR is associated with higher rates of HCC tumor progression at 2-month follow-up imaging after transarterial chemoembolization.

Outpatient Transarterial Chemoembolization of Hepatocellular Carcinoma: Review of a Same-Day Discharge Strategy.

PURPOSE: To test the hypothesis that same-day discharge of selected transarterial chemoembolization patients would not increase 30-day readmission rate compared with overnight observation. MATERIALS AND METHODS: With institutional review board approval, 193 hepatocellular carcinoma patients who underwent transarterial chemoembolization from July 2013 to June 2016 were reviewed. Treatment was conventional/lipiodol transarterial chemoembolization with 50 mg doxorubicin/10 mg mitomycin-c/particles or drug-eluting embolics transarterial chemoembolization with 50-75 mg doxorubicin/vial. At 3 hours, patients tolerating oral intake and not requiring intravenous analgesics were considered for discharge. The primary outcome measure was 30-day readmission for observation versus discharge using chi-squared (χ2) analysis. The secondary aim was to identify baseline or treatment variables independently associated with readmission, including Child-Pugh class, medically managed encephalopathy or ascites, patient age (<65 vs ≥65), tumor number (1 or >1), and level of embolization (segmental vs lobar). RESULTS: Patients underwent 261 transarterial chemoembolization procedures. The 30-day readmission rate was not significantly different between observed patients (n = 179, 9.0%) and discharged patients (n = 82, 13.8%; P = .33). Readmission was not related to the selected agent (conventional/lipiodol-transarterial chemoembolization, 11.0% vs drug-eluting embolics transarterial chemoembolization, 7.5%; P = .36). Baseline variables associated with readmission were Child-Pugh B/C (χ2 = 7.9, P < .01), history of encephalopathy (χ2 = 15.4, P < 0.01), and ascites (χ2 = 4.4, P < .05). Patient age (<65 vs ≥65), tumor number (1 vs >1), and level of embolization (segmental vs lobar) were not predictive of readmission (all P > .05). CONCLUSIONS: Same-day discharge after transarterial chemoembolization does not increase the risk of 30-day readmission. Child-Pugh B/C patients, as well as those with ascites or encephalopathy, have the highest risk of readmission.

Are prophylactic antibiotics necessary prior to transarterial chemoembolization for hepatocellular carcinoma in patients with native biliary anatomy?

BACKGROUND AND OBJECTIVES: Prophylactic antibiotics are frequently administered for transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). In patients without previous biliary instrumentation, infection risk from TACE is low. We hypothesized that there is a negligible rate of infection in these patients without prophylactic antibiotics. METHODS: We reviewed consecutive patients undergoing TACE between 7/1/2013-6/15/2016. All patients had an intact Sphincter of Oddi, received no peri-procedural antibiotics, and had 30+ days follow-up. Level of arterial selection was recorded. Baseline Child-Pugh (CP) and Barcelona Clinic Liver Cancer (BCLC) scores were recorded. The primary outcome measure was the absence of clinical or imaging findings of hepatic abscess within 30 days. RESULTS: A total of 171 patients underwent 235 TACE procedures. CP scores were A (n = 109), B (n = 47), and C (n = 15). BCLC scores were 0 (n = 1), A (n = 108), B (n = 47), and C (n = 15). TACE was performed segmentally (n = 208) or lobar (n = 27). Three patients died of non-infectious causes before 30 days. No hepatic abscesses developed in evaluable patients: 0/232 infusions. CONCLUSIONS: In patients with HCC and an intact Sphincter of Oddi, TACE was performed safely without prophylactic antibiotics. The majority of the patients were BCLC and CP A/B. Additional study of BCLC and CP C patients is warranted.

Bridging and downstaging with TACE in early and intermediate stage hepatocellular carcinoma: Predictors of receiving a liver transplant.

Background and Aims: In patients with surgically unresectable early and intermediate stage hepatocellular carcinoma (HCC), only liver transplant (LT) offers a cure. Locoregional therapies, such as transarterial chemoembolization (TACE), are widely used to bridge patients waiting for an LT or downstage tumors beyond Milan Criteria (MC). However, there are no formal guidelines on the number of TACE procedures patients should receive. Our study explores the extent to which repeated TACE might offer diminishing gains toward LT. Approach: We retrospectively analyzed 324 patients with BCLC stage A and B HCC who had received TACE with the intention of disease downstaging or bridging to LT. In addition to baseline demographics, we collected data on LT status, survival, and the number of TACE procedures. Overall survival (OS) rates were estimated using the Kaplan-Meier method, and correlative studies were calculated using chi-square or Fisher's exact test. Results: Out of 324 patients, 126 (39%) received an LT, 32 (25%) of whom had responded favorably to TACE. LT significantly improved OS: HR 0.174 (0.094-0.322, P < .001). However, the LT rate significantly decreased if patients received ≥3 vs < 3 TACE procedures (21.6% vs 48.6%, P < .001). If their cancer was beyond MC after the third TACE, the LT rate was 3.7%. Conclusions: An increased number of TACE procedures may have diminishing returns in preparing patients for LT. Our study suggests that alternatives to LT, such as novel systemic therapies, should be considered for patients whose cancers are beyond MC after three TACE procedures.

Oncologic Interventions: Periprocedural Medications.

Significant advances in ablative and endovascular therapies have allowed interventional radiology to play a substantial role in the management of patients with malignant neoplasms. The evolution of these procedures and the optimization of patient outcomes and experience must take into account various elements of the periprocedural period. Some of the most important considerations within the periprocedural period are the pharmacologic agents used to avoid infectious complications, decrease pain, and manage side effects. In this article, we discuss some of the most commonly used medications in interventional oncology procedures including antibiotics, narcotics, sedatives, antiemetics, and others.

Resolution of hydronephrosis after uterine artery embolization for fibroids.

PURPOSE: To determine the prevalence, predisposing factors, and resolution of hydronephrosis among patients undergoing uterine artery embolization (UAE) for fibroids. MATERIALS AND METHODS: From October 2004 to May 2008, 1,114 patients underwent UAE at an academic medical center. Hydronephrosis was found on angiographic images in 101 patients. In 34 of these patients, 3-month ultrasound follow-up was available. The angiographic images were graded for hydronephrosis severity by three interventional radiologist reviewers. The degree of residual hydronephrosis was obtained from ultrasound images or reports in 3-month follow-up imaging. Descriptive statistics summarizing outcomes and interobserver agreement regarding hydronephrosis grade were calculated. In a parallel assessment, prospectively gathered baseline data available from 776 patients undergoing UAE were analyzed to identify predisposing factors to hydronephrosis. RESULTS: Among the 34 patients with hydronephrosis and appropriate follow-up, resolution occurred in 28 of 34 (82%) patients. Among the entire study group, 9.0% (101 of 1,114) of patients had unilateral or bilateral hydronephrosis. Hydronephrosis was less frequent in left kidneys (4.5% [35 of 776]) than right kidneys (6.3% [49 of 776]; P = .013). The mean uterine volume in the group with hydronephrosis was greater than in the group without hydronephrosis (1,041 cm(3) vs 609 cm(3); P < .0001), and the mean dominant fibroid volume was also greater (233 cm(3) vs 147 cm(3); P < .0001). CONCLUSIONS: These results suggest that UAE may result in resolution of hydronephrosis in a notable number of cases. Large uterine size and dominant fibroid size was associated with hydronephrosis.

Radiofrequency ablation of lung tumors in swine assisted by a navigation device with preprocedural volumetric planning.

PURPOSE: To develop an image guidance system that incorporates volumetric planning of spherical ablations and electromagnetic tracking of radiofrequency (RF) electrodes during insertion. MATERIALS AND METHODS: Simulated tumors were created in three live swine by percutaneously injecting agar nodules into the lung. A treatment plan was devised for each tumor with optimization software to solve the planning problem. The desired output was the minimum number of overlapping ablation spheres necessary to ablate each tumor and the margin. The insertion plan was executed with use of the electromagnetic tracking system that guided the insertion of the probe into precomputed locations. After a 72-hour survival period, animals were killed and histopathologic sections of the tissue were examined for cell viability and burn pattern analysis. RESULTS: A planning algorithm to spherically cover the tumors and the margin was computed. Electromagnetic tracking allowed successful insertion of the instrument, and impedance roll-off was reached in all ablations. Depending on their size, the tumors and the tumor margins were successfully covered with two to four ablation spheres. The image registration error was 1.0 mm +/- 0.64. The overall error of probe insertion was 9.4 mm +/- 3.0 (N = 8). Analysis of histopathologic sections confirmed successful ablations of the tissue. CONCLUSIONS: Computer-assisted RF ablation planning and electromagnetically tracked probe insertion were successful in three swine, validating the feasibility of electromagnetic tracking-assisted tumor targeting. Image misregistration caused by respiratory motion and tissue deformation contributed to the overall error of probe insertion.

Safety and Tolerability of Topotecan-Eluting Radiopaque Microspheres for Hepatic Chemoembolization in a Rabbit Preclinical Model.

PURPOSE: Topotecan is a camptothecin analogue with potential advantages over irinotecan for transarterial chemoembolization (TACE) of hepatic colorectal metastases including greater anti-neoplastic activity without enzymatic activation. The purpose of this study was to assess safety and tolerability of topotecan-loaded radiopaque microspheres (ROMTOP) administered by TACE in a rabbit model and to compare the in vitro elution of topotecan from microspheres to irinotecan. MATERIALS AND METHODS: Topotecan was loaded into radiopaque microspheres (70-150 µm, DC Bead LUMI™, Biocompatibles UK Ltd-Boston Scientific Corporation) to the maximum capacity of 80 mg/mL of microspheres. Six healthy New Zealand White rabbits underwent hepatic TACE with ROMTOP under fluoroscopic guidance until angiographic stasis. Assessment of toxicities included regular liver function tests and complete blood counts until euthanasia 28 days post-TACE. In vitro topotecan elution from the microspheres was assessed using an open-loop flow-through system and compared to irinotecan. RESULTS: The mean bead volume and topotecan dose delivered were 0.086 mL (0.076-0.105 mL) and 1.99 mg/kg (1.51-2.55 mg/kg), respectively. Aspartate aminotransferase and alanine aminotransferase were elevated post-embolization but resolved within 2 weeks. One rabbit died two days after TACE with pyloric duodenal perforation observed at necropsy, potentially due to non-target embolization. In vitro elution of topotecan from ROMTOP was complete in 10 h compared to 3 h for irinotecan-loaded microspheres. CONCLUSION: Selective embolization with ROMTOP was tolerated at a dose of 2 mg/kg (24 mg/m2) in rabbits. In vitro topotecan elution from microspheres was more prolonged compared to irinotecan.

PET/CT-guided biopsy with respiratory motion correction.

PURPOSE: Given the ability of positron emission tomography (PET) imaging to localize malignancies in heterogeneous tumors and tumors that lack an X-ray computed tomography (CT) correlate, combined PET/CT-guided biopsy may improve the diagnostic yield of biopsies. However, PET and CT images are naturally susceptible to problems due to respiratory motion, leading to imprecise tumor localization and shape distortion. To facilitate PET/CT-guided needle biopsy, we developed and investigated the feasibility of a workflow that allows to bring PET image guidance into interventional CT suite while accounting for respiratory motion. METHODS: The performance of PET/CT respiratory motion correction using registered and summed phases method was evaluated through computer simulations using the mathematical 4D extended cardiac-torso phantom, with motion simulated from real respiratory traces. The performance of PET/CT-guided biopsy procedure was evaluated through operation on a physical anthropomorphic phantom. Vials containing radiolabeled 18F-fluorodeoxyglucose were placed within the physical phantom thorax as biopsy targets. We measured the average distance between target center and the simulated biopsy location among multiple trials to evaluate the biopsy localization accuracy. RESULTS: The computer simulation results showed that the RASP method generated PET images with a significantly reduced noise of 0.10 ± 0.01 standardized uptake value (SUV) as compared to an end-of-expiration image noise of 0.34 ± 0.04 SUV. The respiratory motion increased the apparent liver lesion size from 5.4 ± 1.1 to 35.3 ± 3.0 cc. The RASP algorithm reduced this to 15.7 ± 3.7 cc. The distances between the centroids for the static image lesion and two moving lesions in the liver and lung, when reconstructed with the RASP algorithm, were 0.83 ± 0.72 mm and 0.42 ± 0.72 mm. For the ungated imaging, these values increased to 3.48 ± 1.45 mm and 2.5 ± 0.12 mm, respectively. For the ungated imaging, this increased to 1.99 ± 1.72 mm. In addition, the lesion activity estimation (e.g., SUV) was accurate and constant for images reconstructed using the RASP algorithm, whereas large activity bias and variations (± 50%) were observed for lesions in the ungated images. The physical phantom studies demonstrated a biopsy needle localization error of 2.9 ± 0.9 mm from CT. Combined with the localization errors due to respiration for the PET images from simulations, the overall estimated lesion localization error would be 3.08 mm for PET-guided biopsies images using RASP and 3.64 mm when using ungated PET images. In other words, RASP reduced the localization error by approximately 0.6 mm. The combined error analysis showed that replacing the standard end-of-expiration images with the proposed RASP method in PET/CT-guided biopsy workflow yields comparable lesion localization accuracy and reduced image noise. CONCLUSION: The RASP method can produce PET images with reduced noise, attenuation artifacts and respiratory motion, resulting in more accurate lesion localization. Testing the PET/CT-guided biopsy workflow using computer simulation and physical phantoms with respiratory motion, we demonstrated that guided biopsy procedure with the RASP method can benefit from improved PET image quality due to noise reduction, without compromising the accuracy of lesion localization.

Percutaneous transhepatic vs. endoscopic retrograde biliary drainage for suspected malignant hilar obstruction: study protocol for a randomized controlled trial.

BACKGROUND: The optimal approach to the drainage of malignant obstruction at the liver hilum remains uncertain. We aim to compare percutaneous transhepatic biliary drainage (PTBD) to endoscopic retrograde cholangiography (ERC) as the first intervention in patients with cholestasis due to suspected malignant hilar obstruction (MHO). METHODS: The INTERCPT trial is a multi-center, comparative effectiveness, randomized, superiority trial of PTBD vs. ERC for decompression of suspected MHO. One hundred and eighty-four eligible patients across medical centers in the United States, who provide informed consent, will be randomly assigned in 1:1 fashion via a web-based electronic randomization system to either ERC or PTBD as the initial drainage and, if indicated, diagnostic procedure. All subsequent clinical interventions, including crossover to the alternative procedure, will be dictated by treating physicians per usual clinical care. Enrolled subjects will be assessed for successful biliary drainage (primary outcome measure), adequate tissue diagnosis, adverse events, the need for additional procedures, hospitalizations, and oncological outcomes over a 6-month follow-up period. Subjects, treating clinicians and outcome assessors will not be blinded. DISCUSSION: The INTERCPT trial is designed to determine whether PTBD or ERC is the better initial approach when managing a patient with suspected MHO, a common clinical dilemma that has never been investigated in a randomized trial. TRIAL REGISTRATION: ClinicalTrials.gov, Identifier: NCT03172832 . Registered on 1 June 2017.

Biomedical imaging research opportunities workshop IV: a white paper.

The Fourth Biomedical Imaging Research Opportunities Workshop (BIROW IV) was held on February 24-25, 2006, in North Bethesda, MD. The workshop focused on opportunities for research and development in four areas of imaging: imaging of rodent models; imaging in drug development; imaging of chronic metabolic disease: diabetes; and image guided intervention in the fourth dimension-time. These topics were examined by four keynote speakers in plenary sessions and then discussed in breakout sessions devoted to identifying research opportunities and challenges in the individual topics. This paper synthesizes these discussions into a strategy for future research directions in biomedical imaging.

Complications of thoracic computed tomography-guided fiducial placement for the purpose of stereotactic body radiation therapy.

PURPOSE: This study examined the complication rates associated with percutaneous fiducial placement for the purpose of stereotactic body radiation therapy of primary and metastatic lung neoplasms. PATIENTS AND METHODS: This is a retrospective review of computed tomography (CT) scans and follow-up chest radiographs of 48 consecutive patients who underwent CT-guided percutaneous fiducial placement. The effect of age, sex, number of fiducials placed, and performance of a concomitant biopsy on the complication rates were assessed. RESULTS: Of 48 patients with a total of 221 fiducials placed, 16 (33%) had a procedure-related pneumothorax. There was no significant difference in pneumothorax rate based on age (P = 0.16), sex (P > 0.99), and number of fiducials placed (P = 0.21). Overall, 6 of 48 patients (12.5%) required a thoracostomy tube. Performance of a concomitant core needle biopsy at the time of fiducial placement was associated with pneumothorax rates of 64% compared with 26% without biopsies (P = 0.03). Postprocedural CT demonstrated hemorrhage in 9 patients (19%). Two patients had hemoptysis; one required admission. Patients' age, sex, number of fiducials placed, and performance of concomitant biopsy had no statistically significant implications on parenchymal hemorrhage incidence. CONCLUSION: Approximately one third of the patients develop a pneumothorax during CT-guided fiducial placement. Most are asymptomatic and do not require a thoracostomy. A concurrent biopsy at the time of fiducial placement is associated with an increased risk of pneumothorax. Hemorrhage occurs but is usually clinically insignificant.

Frequency and extent of uterine perfusion via ovarian arteries observed during uterine artery embolization for leiomyomas.

OBJECTIVE: The objective of our study was to evaluate the frequency and extent of residual uterine perfusion via the ovarian arteries after bilateral uterine artery embolization (UAE) for the treatment of symptomatic uterine leiomyomas. MATERIALS AND METHODS: One hundred forty-five consecutive patients who underwent UAE were retrospectively evaluated for blood supply to the uterus via the ovarian arteries after UAE. After completion of UAE, uterine supply from the ovarian arteries was assessed by performing abdominal aortography in all patients. Selective ovarian arteriography, in addition, was performed in some patients. The criteria used to characterize ovarian artery perfusion as seen on the aortograms were vessel size compared with a 5-French catheter and visualization and extent of flow. When the ovarian arteries visibly supplied uterine tissue, a quantification system was applied as follows: the uterus was divided in 24 segments on the basis of a clock model that was superimposed over the uterine territory in the anteroposterior projection. Depending on its distance from the midpoint of the clock, perfusion segments were labeled as central, middle, distal, or peripheral for each hour of the clock resulting in a total of 24 (12 x 2) potential segments of residually perfused uterine tissue via the ovarian arteries. RESULTS: Two hundred ninety ovarian arteries were evaluated on aortography; of these, 202 (70%) were not seen during aortography. Of the visualized ovarian arteries (n = 88), 52% (46/88) were smaller than, 25% (22/88) were equal to, and 23% (20/88) were larger than the diameter of a 5-French catheter. The aortogram revealed that 61% (54/88) of the ovarian arteries extended into the pelvis, whereas 38% (33/88 [one missing data point]) did not. Selective injections were performed in 54 ovarian arteries. Of these, 69% (37/54) of the ovarian arteries had residual fibroid perfusion from the ovarian arteries after UAE (10 left-sided, 15 right-sided, six bilateral = 37 ovarian arteries). Residual fibroid perfusion was more likely in large ovarian arteries, particularly those with rapid flow visualized extending into the pelvis. The perfusion scores ranged from one to 18 segments (< 6 segments, n = 21 ovarian arteries; 6-12 segments, n = 12; > 12 segments, n = 4). Direct communication with the uterine arteries was seen in 20 ovarian arteries, 40% (8/20) of which did not show any uterine or fibroid perfusion, suggesting that fibroid flow had been occluded by UAE. CONCLUSION: Based on aortography, the presence of residual fibroid perfusion is more likely if the ovarian arteries are large, have rapid flow, or have flow that extends into the pelvis. Selective ovarian artery evaluation may be indicated in these cases to determine the extent of residual fibroid perfusion.

Implementation of an electromagnetic tracking system for accurate intrahepatic puncture needle guidance: accuracy results in an in vitro model.

RATIONALE AND OBJECTIVES: Electromagnetic tracking potentially may be used to guide percutaneous needle-based interventional procedures. The accuracy of electromagnetic guided-needle puncture procedures has not been specifically characterized. This article reports the functional accuracy of a needle guidance system featuring real-time tracking of respiratory-related target motion. MATERIALS AND METHODS: A needle puncture algorithm based on a "free-hand" needle puncture technique for percutaneous intrahepatic portocaval systemic shunt was employed. Preoperatively obtained computed tomographic images were displayed on a graphical user interface and registered with the electromagnetically tracked needle position. The system and procedure was tested on an abdominal torso phantom containing a liver model mounted on a motor-driven platform to simulate respiratory excursion. The liver model featured two hollow tubes to simulate intrahepatic vessels. Registration and respiratory motion tracking was performed using four skin fiducials and a needle fiducial within the liver. Success rates for 15 attempts at simultaneous puncture of the two "vessels" of different luminal diameters guided by the electromagnetic tracking system were recorded. RESULTS: Successful "vessel" puncture occurred in 0%, 33%, and 53% of attempts for 3-, 5-, and 7-mm diameter "vessels," respectively. Using a two-dimensional accuracy prediction analysis, predicted accuracy exceeded actual puncture accuracy by 25%-35% for all vessel diameters. Accuracy outcome improved when depth-only errors were omitted from the analysis. CONCLUSIONS: Actual puncture success rate approximates predicted rates for target vessels 5 mm in diameter or greater when depth errors are excluded. Greater accuracy for smaller diameter vessels would be desirable for implementation in a broader range of clinical applications.

Angiographic and interventional options in obstetric and gynecologic emergencies.

This article describes the role of angiographic and interventional techniques in the management of obstetrical and gynecologic hemorrhage. The complementary role of endovascular therapy is discussed and a review of management options for both peripartum hemorrhage and gynecologic hemorrhage is presented. The article describes special management options involving angiographic techniques for placentation abnormalities and arteriovenous malformations, and discusses a limited role for embolization in the management of ectopic pregnancies. The authors also present the outcomes of embolotherapy, associated complications, and implications for future fertility. This article describes the role of embolotherapy as it has evolved over the last three decades and clarifies the endovascular management options available to patients.

Electromagnetic tracking for abdominal interventions in computer aided surgery.

Electromagnetic tracking has great potential for assisting physicians in precision placement of instruments during minimally invasive interventions in the abdomen, since electromagnetic tracking is not limited by the line-of-sight restrictions of optical tracking. A new generation of electromagnetic tracking has recently become available, with sensors small enough to be included in the tips of instruments. To fully exploit the potential of this technology, our research group has been developing a computer aided, image-guided system that uses electromagnetic tracking for visualization of the internal anatomy during abdominal interventions. As registration is a critical component in developing an accurate image-guided system, we present three registration techniques: 1) enhanced paired-point registration (time-stamp match registration and dynamic registration); 2) orientation-based registration; and 3) needle shape-based registration. Respiration compensation is another important issue, particularly in the abdomen, where respiratory motion can make precise targeting difficult. To address this problem, we propose reference tracking and affine transformation methods. Finally, we present our prototype navigation system, which integrates the registration, segmentation, path-planning and navigation functions to provide real-time image guidance in the clinical environment. The methods presented here have been tested with a respiratory phantom specially designed by our group and in swine animal studies under approved protocols. Based on these tests, we conclude that our system can provide quick and accurate localization of tracked instruments in abdominal interventions, and that it offers a user-friendly display for the physician.