Image Fusion Technology in Interventional Radiology.

Image fusion technology aims to improve patient outcomes for image-guided interventions by leveraging the strengths of multimodality imaging datasets. This most commonly involves the overlay or co-display of advanced cross-sectional imaging permitting freedom of device placement via conventional image guidance such as ultrasound, fluoroscopy, and computed tomography. This can allow the interventionalist to target and treat lesions that would otherwise be difficult or impossible to visualize and access using conventional imaging guidance. Furthermore, the use of image fusion can allow for procedures traditionally performed with cross-sectional imaging to be performed under ultrasound or fluoroscopy, by importing the data from preacquired cross-sectional imaging into the interventional procedure. This manuscript provides an overview of image fusion technologies used for interventional radiology (IR) guidance, with an emphasis on technical considerations.

Correction to: Comparing Percutaneous Transluminal Angioplasty and Stent Placement for Treatment of Subclavian Arterial Occlusive Disease: A Systematic Review and Meta-Analysis.

The original version of this paper contained an error.

CT-guided Transosseous Soft Tissue Biopsy: Techniques, Outcomes and Complications in 50 Cases.

PURPOSE: To describe the techniques, outcomes and complications of CT-guided transosseous biopsy of soft tissue lesions via multiple different routes. MATERIALS AND METHODS: Clinical and radiologic data from all consecutive soft tissue biopsies performed via a transosseous approach between April 2009 and July 2015 were retrospectively compiled. Fifty biopsies performed in 50 patients (n = 17 males, n = 33 females) were included. Biopsies were performed using a 13-gauge biopsy needle which was advanced through the selected bone to the lesion margin followed by coaxial placement of either an 18- or 20-gauge biopsy gun. Sampling accuracy was determined from the final pathology report as diagnostic or non-diagnostic. Complications included rates of pneumothorax, pneumomediastinum, hemoptysis, immediate admission, chest tube insertion, surgical consultation, 30-day readmission, fracture, osteomyelitis or tract seeding. RESULTS: Number of diagnostic samples per bone included: sternum (n = 17, 34%), rib (n = 7, 14%), scapula (n = 6, 12%), transverse process (n = 4, 8%), vertebral body (n = 4, 8%), spinous process (n = 1, 2%), ilium (n = 7, 14%), sacrum (n = 4, 8%). Complications included 10 pneumothoraces in 39 cases that crossed the pleura, 8 pneumomediastinum in 17 transsternal cases, one immediate surgical consultation and one 30-day readmission. CONCLUSION: Transosseous biopsy approach is a technically feasible means of obtaining core needle samples of soft tissue lesions. LEVEL OF EVIDENCE: Case series, IV.

Opercular Index Score: a CT angiography-based predictor of capillary robustness and neurological outcomes in the endovascular management of acute ischemic stroke.

BACKGROUND: Many CT angiography (CTA) collateral scoring systems are either subjective or complex and time consuming. OBJECTIVE: To evaluate the correlation between a CTA collateral scoring system-the Opercular Index Score (OIS)-with neurological outcomes at 90 days following endovascular treatment for acute ischemic stroke (AIS) secondary to large vessel occlusion. METHODS: Fifty-five patients with AIS due to distal internal carotid artery, M1, or proximal M2 occlusions who underwent endovascular treatment were included. OIS was retrospectively calculated from CTA images, reconstructed from CT perfusion imaging, as the ratio of opacified M3 opercular branches in the Sylvian fissure on the unaffected side to those on the stroke side and dichotomized into favorable (OIS≤2) and poor (OIS>2). The ability of OIS to predict good neurological outcomes (modified Rankin Scale score ≤2 at 90 days) was assessed using sensitivity, specificity, and area under the curve (AUC) with receiver operating characteristic analysis. RESULTS: Thirty-five patients had a favorable OIS and 20 patients had a poor OIS. Patients with favorable OIS had an 80.0% (n=28) rate of good neurological outcomes compared with 15.0% (n=3) of patients with a poor OIS (p<0.0001). On multivariate logistic regression analysis adjusting for baseline National Institutes of Health Stroke Scale score, OIS, and device used, favorable OIS was the only variable independently associated with good neurological outcome (OR=17.2, 95% CI 3.8 to 104.3) and demonstrated a sensitivity of 90.3% and specificity of 70.8% with an AUC of 0.822. CONCLUSIONS: OIS is a simple and practical non-invasive scoring system that can be used to predict collateral robustness and good neurological outcome among patients with AIS undergoing endovascular treatment.

Comparing Percutaneous Transluminal Angioplasty and Stent Placement for Treatment of Subclavian Arterial Occlusive Disease: A Systematic Review and Meta-Analysis.

BACKGROUND AND PURPOSE: Subclavian artery occlusive disease (SAOD) is often associated with cerebrovascular symptoms such as subclavian steal syndrome and stroke. We conducted a systematic review and meta-analysis to compare percutaneous transluminal angioplasty (PTA) and stent placement for the treatment of SAOD. MATERIALS AND METHODS: We searched Medline, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus through October 16, 2014. From each study, we abstracted baseline patient characteristics, study design variables, and outcome data including rates of technical success, primary patency (≤2 and >2 years follow-up), symptom resolution, and complications. Meta-analysis was performed using a random-effects model. RESULTS: A total of 35 non-comparative studies with 1726 patients were included. Technical success rate was significantly higher in the stent group than the PTA group (92.8 vs 86.8%, p = 0.007). Long-term primary patency rates (76.9 vs 79.6%, p = 0.729) and symptom resolution rates (82.2 vs 73.0%, p = 0.327) were not statistically different. There was no statistically significant difference in the rates of stroke or death. CONCLUSION: Stent placement for treatment of SAOD may be associated with higher rates of technical success but similar rates of symptom resolution and long-term outcomes. The confidence in the available estimates is low. Further comparative studies are needed to guide patients and clinicians in shared decision making.

Percutaneous Cryoablation vs Partial Nephrectomy: Cost Comparison of T1a Tumors.

PURPOSE: To compare cost of percutaneous cryoablation vs open and robot-assisted partial nephrectomy of T1a renal masses from the hospital perspective. MATERIALS AND METHODS: We retrospectively compared cost, clinical and tumor data of 37 percutaneous cryoablations to 26 open and 102 robot-assisted partial nephrectomies. Total cost was the sum of direct and indirect cost of procedural and periprocedural variables. Clinical data included demographics, Charlson Comorbidity Index (CCI), hospitalization time, complication rate, ICU admission rate, and 30-day readmission rates. Tumor data included size, RENAL nephrometry score, and malignancy rate. Student's t-test was used for continuous variables and Fisher's exact or chi-square tests for categorical data. RESULTS: Mean total cost was lower for percutaneous cryoablation than open or robot-assisted partial nephrectomy: $6067 vs $11392 or $11830 (p<0.0001) with lower cost of procedure room: $1516 vs $3272 or $3254 (p<0.0001), room and board: $95 vs $1907 or $1106 (p<0.0001), anesthesia: $684 vs $1223 or $1468 (p<0.0001), and laboratory/pathology fees: $205 vs $804 or $720 (p<0.0001). Supply and device cost was higher than open: $2596 vs $1352 (p<0.0001), but lower than robot-assisted partial nephrectomy: $3207 (p=0.002). Mean hospitalization times were lower for percutaneous cryoablation (p<0.0001), while age and CCI were higher (p<0.0001). No differences in tumor size, nephrometry score, malignancy rate complication, ICU, or 30-day readmission rates were observed. CONCLUSION: Percutaneous cryoablation can be performed at significantly lower cost than open and robotic partial nephrectomies for similar masses.

High-Intensity Focused Ultrasound: Current Status for Image-Guided Therapy.

Image-guided high-intensity focused ultrasound (HIFU) is an innovative therapeutic technology, permitting extracorporeal or endocavitary delivery of targeted thermal ablation while minimizing injury to the surrounding structures. While ultrasound-guided HIFU was the original image-guided system, MR-guided HIFU has many inherent advantages, including superior depiction of anatomic detail and superb real-time thermometry during thermoablation sessions, and it has recently demonstrated promising results in the treatment of both benign and malignant tumors. HIFU has been employed in the management of prostate cancer, hepatocellular carcinoma, uterine leiomyomas, and breast tumors, and has been associated with success in limited studies for palliative pain management in pancreatic cancer and bone tumors. Nonthermal HIFU bioeffects, including immune system modulation and targeted drug/gene therapy, are currently being explored in the preclinical realm, with an emphasis on leveraging these therapeutic effects in the care of the oncology patient. Although still in its early stages, the wide spectrum of therapeutic capabilities of HIFU offers great potential in the field of image-guided oncologic therapy.

Navigational Tools for Interventional Radiology and Interventional Oncology Applications.

The interventional radiologist is increasingly called upon to successfully access challenging biopsy and ablation targets, which may be difficult based on poor visualization, small size, or the proximity of vulnerable regional anatomy. Complex therapeutic procedures, including tumor ablation and transarterial oncologic therapies, can be associated with procedural risk, significant procedure time, and measurable radiation time. Navigation tools, including electromagnetic, optical, laser, and robotic guidance systems, as well as image fusion platforms, have the potential to facilitate these complex interventions with the potential to improve lesion targeting, reduce procedure time, and radiation dose, and thus potentially improve patient outcomes. This review will provide an overview of currently available navigational tools and their application to interventional radiology and oncology. A summary of the pertinent literature on the use of these tools to improve safety and efficacy of interventional procedures compared with conventional techniques will be presented.

Yttrium-90 Infusion: Incidence and Outcome of Delivery System Occlusions during 885 Deliveries.

PURPOSE: To evaluate the incidence, cause, and management of delivery system occlusions during yttrium-90 (90Y) microsphere infusions and to identify techniques to prevent occlusions. MATERIALS AND METHODS: A retrospective review was conducted of 885 consecutive radioembolization deliveries during 820 procedures (some with multiple deliveries) in 503 patients (mean age, 65 y; 293 male) performed between June 2001 and July 2013 at a single academic tertiary care hospital. Occlusions were reported prospectively, and procedural details were reviewed. Statistical analysis assessed associations between catheter occlusions and patient and procedural characteristics. RESULTS: Of 885 90Y microsphere deliveries, 11 resulted in occlusion (1.2%). Five occlusions were associated with contained leakage of radioactive material, and one was associated with a spill. Treatment was completed in the same day in 10 patients; repeat catheterization was required in five patients. One patient returned 1 week later to complete treatment. Occlusions were more frequent with deliveries of resin (11/492; 2.2%) versus glass (0/393; 0%) microspheres (P = .002). Occlusions were more likely to occur within the proximal portion of the delivery apparatus (P = .002). There was no significant relationship with any patient characteristics, and there was no improvement with operator experience. The most common cause of occlusion was resin microsphere delivery device failure. CONCLUSIONS: (90)Y microsphere delivery device occlusion is uncommon but does occur with resin microspheres. Understanding causes and how to troubleshoot can limit the incidence and detrimental effects.

Intractable Hiccups Due to Posterior Inferior Cerebellar Artery Aneurysm.

This is the third reported case of a posterior inferior cerebellar artery (PICA) aneurysm presenting as intractable hiccups (IH). A previously healthy 29-year-old woman was admitted with a 2-week history of hiccups occurring >100 times per minute. Symptoms persisted despite numerous noninvasive therapies. Magnetic resonance imaging and magnetic resonance angiogram of the brain showed a left PICA aneurysm that was confirmed by catheter angiography. Symptoms resolved following suboccipital craniotomy and resection. Although rare, PICA aneurysm is a potentially curable cause of IH.

Systemic mastocytosis: a rare cause of single vertebral body uptake on bone scan.

Systemic Mastocytosis is a rare condition characterized by the abnormal proliferation of Mast Cells. Presentation as a solitary vertebral body lesion is extremely uncommon and may be confused with more ominous conditions such as metastasis. Familiarity with the condition can heighten clinical suspicion, direct tissue diagnosis, guide management and indicate appropriate follow up. We present a case of a 64-year-old woman undergoing staging for recently diagnosed breast cancer who was found to have Systemic Mastocytosis of a single vertebral body.

Endovenous Laser Ablation of Perforating Veins: Feasibility, Safety, and Occlusion Rate Using a 1,470-nm Laser and Bare-Tip Fiber.

PURPOSE: To describe technical feasibility and safety of perforating vein ablation with the use of a 1,470-nm laser and bare-tip fiber in the management of chronic venous insufficiency (CVI). MATERIALS AND METHODS: A total of 171 perforating veins were ablated in 101 limbs of 87 patients (mean age, 54.4 y; 79% female). Outcomes included sonographic occlusion of ablated perforator, subjective changes of insufficiency symptoms, incidence of procedure-related side effects (pain, hyperpigmentation), and complications (burn, infection, deep vein thrombosis, paresthesia). Correlation between perforator closure and patient symptoms was assessed by Pearson χ(2) test. Factors influencing failure of perforator closure were analyzed by analysis of variance. RESULTS: Forty-nine perforating veins had previous great saphenous vein (GSV) interruption, 25 had previous small saphenous vein (SSV) interruption, 88 had previous GSV and SSV interruption, and 9 had competent saphenous systems. Ninety-one ablations were combined with microphlebectomy, 55 were combined with sclerotherapy, and 25 were performed alone. At 1 and 3 months' follow-up, 94% and 98% of ablated perforators were sonographically occluded, and 82% and 96% of patients noted complete symptom resolution, respectively. Complications included 5 cases of new-onset paresthesia and 1 case of nonocclusive deep vein thrombosis. Ablation failed in 10 perforators, and treatment failure showed significant correlations with higher clinical, etiology, anatomy, and physiology score (P = .002) and history of GSV/SSV interruption (P = .042). CONCLUSIONS: Three-month closure of perforating veins is achievable by using a 1,470-nm laser and bare-tip fiber and can be safely performed alone or in combination with microphlebectomy or sclerotherapy at all stages of CVI severity.

Safety and efficacy of angiographic occlusion of duodenal varices as an alternative to TIPS: review of 32 cases.

UNLABELLED: BACKGROUND/RATIONALE OF STUDY: Analyze safety and efficacy of angiographic-occlusion-with-sclerotherapy/embolotherapy-without-transjugular-intrahepatic-portosystemic-shunt (TIPS) for duodenal varices. Although TIPS is considered the best intermediate-to-long term therapy after failed endoscopic therapy for bleeding varices, the options are not well-defined when TIPS is relatively contraindicated, with scant data on alternative therapies due to relative rarity of duodenal varices. Prior cases were identified by computerized literature search, supplemented by one illustrative case. Favorable clinical outcome after angiography defined as no rebleeding during follow-up, without major procedural complications. RESULTS: Thirty-two cases of duodenal varices treated by angiographic-occlusion-with-sclerotherapy/embolotherapy- without-TIPS were analyzed. Patients averaged 59.5 ± 12.2 years old (female = 59%). Patients presented with melena-16, hematemesis & melena-5, large varices-5, growing varices-2, ruptured varices-1, and other- 3. Twenty-nine patients had cirrhosis; etiologies included: alcoholism-11, hepatitis C-11, primary biliary cirrhosis- 3, hepatitis B-2, Budd-Chiari-1, and idiopathic-1. Three patients did not have cirrhosis, including hepatic metastases from rectal cancer-1, Wilson's disease-1, and chronic liver dysfunction-1. Thirty-one patients underwent esophagogastroduodenoscopy before therapeutic angiography, including fifteen undergoing endoscopic variceal therapy. Therapeutic angiographic techniques included balloon-occluded retrograde-transvenous-obliteration (BRTO) with sclerotherapy and/or embolization-21, DBOE (double-balloon-occluded-embolotherapy)-5, and other-6. Twenty-eight patients (87.5%; 95%-confidence interval: 69-100%) had favorable clinical outcomes after therapeutic angiography. Three patients were therapeutic failures: rebleeding at 0, 5, or 10 days after therapy. One major complication (Enterobacter sepsis) and one minor complication occurred. CONCLUSIONS: This work suggests that angiographic-occlusion-with sclerotherapy/ embolotherapy-without-TIPS is relatively effective (~90% hemostasis-rate), and relatively safe (3% major-complication-rate). This therapy may be a useful treatment option for duodenal varices when endoscopic therapy fails and TIPS is relatively contraindicated.

Comprehensive magnetic resonance enterography of Crohn's disease in the pediatric population: technique, interpretation, and management.

Magnetic resonance enterography (MRE) plays a critical role in the management of Crohn's disease in the pediatric population. The ability to provide dynamic assessment of disease burden, complications, and therapeutic response without ionizing radiation makes it an ideal tool for younger patients requiring frequent follow-up. With a growing array of available treatment options, a sound understanding of MRE is critical in directing management aimed at curbing the physical and emotional morbidity associated with the lifelong condition. The goal of this article is to provide a practical overview of MRE in the pediatric population. This includes a review of our technique, approach to interpretation, pictorial collection of findings, and discussion of the role MRE plays in management.

Endovascular management of ureteroarterial fistula: a rare potentially life threatening cause of hematuria.

Ureteroarterial fistula is a rare, potentially life-threatening cause of hematuria characterized by an abnormal channel between a ureter and artery. The rarity of this condition, complexity of predisposing risk factors and intermittence of symptoms may delay or obscure its diagnosis. With a high index of suspicion and careful angiographic evaluation, embarking on this condition is not only possible but sets the stage for curative intervention. We report a case of a ureteroarterial fistula presenting with intermittent hematuria, successfully diagnosed at angiography and managed with endovascular stent graft placement.

Intracellular calcium signaling pathways during liver ischemia and reperfusion.

Calcium plays a major role in intracellular signaling mechanisms during ischemia reperfusion (I/R) injury of a liver cell. Under ischemic conditions, the absence of oxygen arrests oxidative phosphorylation, thereby eliminating the energy source by which hepatocellular mechanisms maintain homeostasis of calcium. This, in turn, leaves nonselective plasma membrane influx pores unopposed and results in a net increase in intracellular calcium concentrations. Subsequent reperfusion marks the onset and progression of apoptosis and necrosis, as it involves inflammatory responses as well as free-radical formation due to re-oxygenation of cells. These processes destroy the structural integrity of organelles, leading to disruptive redistribution of calcium between cellular and subcellular compartments. This initial elevation and later imbalance of intracellular calcium concentrations associated with I/R induce various molecular responses within each organelle. In the cytoplasm, a series of pro-apoptotic pathways involving various calcium sensitive enzymes are activated. The injury is further exacerbated in the endoplasmic reticulum (ER) due to the malfunction of mechanisms responsible for intracellular calcium sequestration. Both the mitochondria and the nucleus are also adversely affected, as their structural integrity and physiologic functions are disrupted. To date, however, the precise pathophysiology of these calcium-mediated signaling pathways is not fully understood due to its complex nature. This review aims to systematically examine the current literature about individual molecular signaling pathways in the cytoplasm, ER, mitochondria, and the nucleus prior to causing time-sensitive progression of permanent tissue injury.